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Goldmann O, Medina E. Revisiting Pathogen Exploitation of Clathrin-Independent Endocytosis: Mechanisms and Implications. Cells 2025; 14:731. [PMID: 40422234 DOI: 10.3390/cells14100731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2025] [Revised: 05/04/2025] [Accepted: 05/13/2025] [Indexed: 05/28/2025] Open
Abstract
Endocytosis is a specialized transport mechanism in which the cell membrane folds inward to enclose large molecules, fluids, or particles, forming vesicles that are transported within the cell. It plays a crucial role in nutrient uptake, immune responses, and cellular communication. However, many pathogens exploit the endocytic pathway to invade and survive within host cells, allowing them to evade the immune system and establish infection. Endocytosis can be classified as clathrin-mediated (CME) or clathrin-independent (CIE), based on the mechanism of vesicle formation. Unlike CME, which involves the formation of clathrin-coated vesicles that bud from the plasma membrane, CIE does not rely on clathrin-coated vesicles. Instead, other mechanisms facilitate membrane invagination and vesicle formation. CIE encompasses a variety of pathways, including caveolin-mediated, Arf6-dependent, and flotillin-dependent pathways. In this review, we discuss key features of CIE pathways, including cargo selection, vesicle formation, routes taken by internalized cargo, and the regulatory mechanisms governing CIE. Many viruses and bacteria hijack host cell CIE mechanisms to facilitate intracellular trafficking and persistence. We also revisit the exploitation of CIE by bacterial and viral pathogens, highlighting recent discoveries in entry mechanisms, intracellular fate, and host-pathogen interactions. Understanding how pathogens manipulate CIE in host cells can inform the development of novel antimicrobial and immunomodulatory interventions, offering new avenues for disease prevention and treatment.
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Affiliation(s)
- Oliver Goldmann
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Eva Medina
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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Tao Y, Ji H, Hu W, Jiang G, Yang F, Peng X, Zhang X, Yin Y, Yuan Z, Chen D. SMARCC1 promotes M2 macrophage polarization and reduces ferroptosis in lung cancer by activating FLOT1 transcription. J Mol Med (Berl) 2025; 103:453-467. [PMID: 40108025 DOI: 10.1007/s00109-025-02531-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2025] [Revised: 03/05/2025] [Accepted: 03/10/2025] [Indexed: 03/22/2025]
Abstract
Grounded on the bioinformatics insights, this study explores the role of flotillin 1 (FLOT1) in modulating macrophage phenotype and immune evasion in lung cancer cells. The bioinformatics analyses revealed positive correlations between FLOT1 expression and infiltration of M2 macrophages, neutrophils, dendritic cells, and CD4 memory T cells. Furthermore, elevated FLOT1 expression was associated with a poor prognosis in lung cancer patients. Analysis of tumor and adjacent non-tumor tissues from 53 lung cancer patients revealed significantly higher immunohistochemical staining of FLOT1 in tumor tissues, showing positive correlation with the staining intensity of PD-L1. Additionally, staining intensities for markers of M2 macrophages (Arg1), CD4 memory T cells (CD4), dendritic cells (CD83), and neutrophils (CD177) were significantly higher in tumor tissues with high FLOT1 levels. Silencing of FLOT1 was induced in two lung cancer cell lines. Co-culturing in conditioned media of the FLOT1-silenced cancer cells led to reduced chemotactic migration and M2 skewing of macrophages in vitro. Using xenograft models, we observed that FLOT1 silencing weakened tumorigenic activity of A549 cells in mice and reduced M2 macrophage infiltration in tumors. SWI/SNF related BAF chromatin remodeling complex subunit C1 (SMARCC1) was identified as a transcription factor that activated FLOT1 transcription by binding to its promoter. Knockdown of SMARCC1 in lung cancer cells similarly reduced the migration and M2 polarization of macrophages as well as weakened tumorigenesis in mice. However, these effects were counteracted by FLOT1 overexpression. Further analysis of the downstream effectors of the SMARCC1/FLOT1 cascade revealed the enrichment of these factors in ferroptosis-related pathways. Mechanistically, SMARCC1 knockdown led to a decreased GSH:GSSG ratio and increased lipid peroxidation in macrophages, while FLOT1 overexpression restored these changes. Transmission electron microscopic observation revealed typical features of ferroptosis-resistant mitochondria following SMARCC1 knockdown, including fragmented or reduced cristae and increased outer membrane integrity. These mitochondrial changes were mitigated by FLOT1 overexpression. In conclusion, SMARCC1 promotes immune evasion in lung cancer by activating FLOT1 transcription. This activation enhances recruitment and M2 polarization of macrophages, and increases PD-L1 expression, reduces ferroptosis. These findings provide valuable insights into the molecular mechanisms of immune evasion and suggest potential therapeutic targets for lung cancer treatment. KEY MESSAGES: • FLOT1 is associated with poor prognosis in lung cancer patients. • Association between FLOT1 and immune cell infiltration in lung cancer. • Silencing FLOT1 inhibits the recruitment of macrophages by lung cancer cells. • SMARCC1 is highly expressed in lung cancer and promotes the transcription of FLOT1. • FLOT1 overexpression rescues the inhibitory effect of SMARCC1 knockdown on M2 macrophage infiltration and activation of Ferroptosis.
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Affiliation(s)
- Youliang Tao
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Huafeng Ji
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Wensheng Hu
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Guojun Jiang
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Fangding Yang
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Xu Peng
- Department of Orthopedics, The First People's Hospital of Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Xu Zhang
- Department of General Surgery, The First People's Hospital of Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Yuqin Yin
- Department of Nephrology, The First People's Hospital of Lin'an District, Hangzhou, 311300, China
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China
| | - Zhize Yuan
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, 507 Zhengmin Rd, Shanghai, 200433, China.
| | - Dukai Chen
- Department of Thoracic Surgery, The First People's Hospital of Hangzhou Lin'an District, Hangzhou Medical College, No. 360, Yikang Street, Lin'an District, Hangzhou, 311300, China.
- Lin'an Peoples' Hospital Affiliated to Hangzhou Medical College, Hangzhou, 311300, China.
- Lin'an District of Zhejiang Provincial People's Hospital, Hangzhou, 311300, China.
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Wang Y, Miao Z, Qin X, Yang Y, Wu S, Miao Q, Li B, Zhang M, Wu P, Han Y, Li B. Transcriptomic landscape based on annotated clinical features reveals PLPP2 involvement in lipid raft-mediated proliferation signature of early-stage lung adenocarcinoma. J Exp Clin Cancer Res 2023; 42:315. [PMID: 37996944 PMCID: PMC10666437 DOI: 10.1186/s13046-023-02877-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 10/29/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND Image-based screening improves the detection of early-stage lung adenocarcinoma (LUAD)but also highlights the issue of high false-positive diagnoses, which puts patients at a risk of unnecessary over-treatment. Therefore, more precise discrimination criteria are required to ensure that patients with early-stage LUAD receive appropriate treatments. METHODS We integrated 158 early-stage LUAD cases from 2 independent cohorts, including 30 matched resected specimens with complete radiological and pathological information, and 128 retrospective pathological pair-samples with partial follow-up data. This integration allowed us to conduct a correlation analysis between clinical phenotype and transcriptome landscape. Immunohistochemistry was performed using tissue microarrays to examine the expression of phospholipid phosphatase 2 (PLPP2) and lipid-raft markers. Lipidomics analysis was used to determine the changes of lipid components in PLPP2-overexpressed cells. To assess the effects of PLPP2 on the malignant phenotypes of LUAD cells, we conducted mice tumor-bearing experiments and in vitro cellular experiments by knocking down PLPP2 and inhibiting lipid raft synthesis with MβCD, respectively. RESULTS Bioinformatics analysis indicated that the co-occurrence of lipid raft formation and rapid cell proliferation might exhibit synergistic effects in driving oncogenesis from lung preneoplasia to adenocarcinoma. The enhanced activation of the cell cycle promoted the transition from non-invasive to invasive status in early-stage LUAD, which was related to an increase in lipid rafts within LUAD cells. PLPP2 participated in lipid raft formation by altering the component contents of lipid rafts, such as esters, sphingomyelin, and sphingosine. Furthermore, elevated PLPP2 levels were identified as an independent prognostic risk factor for LUAD patients. Further results from in vivo and in vitro experiments confirmed that PLPP2 could induce excessive cell proliferation by enhancing lipid raft formation in LUAD cells. CONCLUSIONS Our study has revealed the characteristics of gene expression profiles in early-stage LUAD patients with the different radiological and pathological subtypes, as well as deciphered transcriptomic evolution trajectory from preneoplasia to invasive LUAD. Furthermore, it suggests that PLPP2-mediated lipid raft synthesis may be a significant biological event in the initiation of early-stage LUAD, offering a potential target for more precise diagnosis and therapy in clinical settings.
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Affiliation(s)
- Yibei Wang
- Department of Developmental Cell Biology, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning, 110122, P. R. China
- Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, P. R. China
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
| | - Ziwei Miao
- Department of Developmental Cell Biology, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning, 110122, P. R. China
| | - Xiaoxue Qin
- Department of Developmental Cell Biology, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning, 110122, P. R. China
| | - Yi Yang
- Department of Laboratory Animals, China Medical University, Shenyang, China
| | - Si Wu
- Department of Biobank, Shengjing Hospital of China Medical University, Shenyang, China
| | - Qi Miao
- Department of Radiology, The First Hospital of China Medical University, Shenyang, China
| | - Beibei Li
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Mingyu Zhang
- Department of Developmental Cell Biology, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning, 110122, P. R. China
| | - Pengfei Wu
- Department of Neurosurgery, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, P. R. China.
| | - Yun Han
- Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, P. R. China.
| | - Bo Li
- Department of Developmental Cell Biology, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning, 110122, P. R. China.
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The Lipid Raft-Associated Protein Stomatin Is Required for Accumulation of Dectin-1 in the Phagosomal Membrane and for Full Activity of Macrophages against Aspergillus fumigatus. mSphere 2023; 8:e0052322. [PMID: 36719247 PMCID: PMC9942578 DOI: 10.1128/msphere.00523-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Alveolar macrophages belong to the first line of defense against inhaled conidia of the human-pathogenic fungus Aspergillus fumigatus. In lung alveoli, they contribute to phagocytosis and elimination of conidia. As a counterdefense, conidia have a gray-green pigment that enables them to survive in phagosomes of macrophages for some time. Previously, we showed that this conidial pigment interferes with the formation of flotillin-dependent lipid raft microdomains in the phagosomal membrane, thereby preventing the formation of functional phagolysosomes. Besides flotillins, stomatin is a major component of lipid rafts and can be targeted to the membrane. However, only limited information on stomatin is available, in particular on its role in defense against pathogens. To determine the function of this integral membrane protein, a stomatin-deficient macrophage line was generated by CRISPR/Cas9 gene editing. Immunofluorescence microscopy and flow cytometry revealed that stomatin contributes to the phagocytosis of conidia and is important for recruitment of the β-glucan receptor dectin-1 to both the cytoplasmic membrane and phagosomal membrane. In stomatin knockout cells, fusion of phagosomes and lysosomes, recruitment of the vATPase to phagosomes, and tumor necrosis factor alpha (TNF-α) levels were reduced when cells were infected with pigmentless conidia. Thus, our data suggest that stomatin is involved in maturation of phagosomes via fostering fusion of phagosomes with lysosomes. IMPORTANCE Stomatin is an integral membrane protein that contributes to the uptake of microbes, e.g., spores of the human-pathogenic fungus Aspergillus fumigatus. By generation of a stomatin-deficient macrophage line by advanced genetic engineering, we found that stomatin is involved in the recruitment of the β-glucan receptor dectin-1 to the phagosomal membrane of macrophages. Furthermore, stomatin is involved in maturation of phagosomes via fostering fusion of phagosomes with lysosomes. The data provide new insights on the important role of stomatin in the immune response against human-pathogenic fungi.
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Wang R, Chen Z, Zhang Y, Xiao S, Zhang W, Hu X, Xiao Q, Liu Q, Wang X. Flotillin-1 is a prognostic biomarker for glioblastoma and promotes cancer development through enhancing invasion and altering tumour microenvironment. J Cell Mol Med 2023; 27:392-402. [PMID: 36647700 PMCID: PMC9889621 DOI: 10.1111/jcmm.17660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/18/2022] [Accepted: 12/25/2022] [Indexed: 01/18/2023] Open
Abstract
Flotillin-1(FLOT1) has long been recognized as a tumour-promoting gene in several types of cancer. However, the expression and function of FLOT1 in glioblastomas (GBM) has not been elucidated. Here, in this study, we find that the expression level of FLOT1 in GBM tissue was much higher than that in normal brain, and the expression was even higher in the more aggressive subtypes and IDH status of glioma. Kaplan-Meier survival revealed that high FLOT1 expression is closely associated with poor outcome in GBM patients. FLOT1 knockdown markedly reduced the proliferation, migration and invasiveness of GBM cells, while FLOT1 overexpression significantly increases GBM cell proliferation, migration and invasiveness. Mechanistically, FLOT1 expression may play a potential role in the microenvironment of GBM. Therefore, FLOT1 promotes GBM proliferation and invasion in vitro and in vivo and may serve as a biomarker of prognosis and therapeutic potential in the fight against GBM.
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Affiliation(s)
- Ran Wang
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina,The Hunan Provincial Key Lab of Precision Diagnosis and Treatment for Gastrointestinal Tumor, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Zhikang Chen
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina,The Hunan Provincial Key Lab of Precision Diagnosis and Treatment for Gastrointestinal Tumor, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Yi Zhang
- Department of Neurosurgery, Dengzhou People's HospitalDengzhouHenanChina
| | - Shihan Xiao
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Wuming Zhang
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Xianqin Hu
- Department of Colorectal and Anus Surgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Qun Xiao
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Qing Liu
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Xiangyu Wang
- Department of Neurosurgery, Xiangya HospitalCentral South UniversityChangshaHunanChina
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6
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Isik OA, Cizmecioglu O. Rafting on the Plasma Membrane: Lipid Rafts in Signaling and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1436:87-108. [PMID: 36648750 DOI: 10.1007/5584_2022_759] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The plasma membrane is not a uniform phospholipid bilayer; it has specialized membrane nano- or microdomains called lipid rafts. Lipid rafts are small cholesterol and sphingolipid-rich plasma membrane islands. Although their existence was long debated, their presence in the plasma membrane of living cells is now well accepted with the advent of super-resolution imaging techniques. It is interesting to note that lipid rafts function to compartmentalize receptors and their regulators and substantially modulate cellular signaling. In this review, we will examine the role of lipid rafts and caveolae-lipid raft-like microdomains with a distinct 3D morphology-in cellular signaling. Moreover, we will investigate how raft compartmentalized signaling regulates diverse physiological processes such as proliferation, apoptosis, immune signaling, and development. Also, the deregulation of lipid raft-mediated signaling during tumorigenesis and metastasis will be explored.
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Affiliation(s)
- Ozlem Aybuke Isik
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Onur Cizmecioglu
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
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7
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Hou L, Du J, Ren Q, Zhu L, Zhao X, Kong X, Gu W, Wang L, Meng Q. Ubiquitin-modified proteome analysis of Eriocheir sinensis hemocytes during Spiroplasma eriocheiris infection. FISH & SHELLFISH IMMUNOLOGY 2022; 125:109-119. [PMID: 35500876 DOI: 10.1016/j.fsi.2022.04.046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Abstract
Spiroplasma eriocheiris, the pathogen of Eriocheir sinensis tremor disease (TD), has bring a huge economic loss to China aquaculture. The hemocytes of crab as the first target cells of S. eriocheiris, but the interactive relationship between the E. sinensis and this pathogen not particularly clear. The present study is the first time to analysis the role of protein ubiquitination in the process of E. sinensis hemocytes response S. eriocheiris infection. By applying label-free quantitative liquid chromatography with tandem mass spectrometry proteomics, 950 lysine ubiquitination sites and 803 ubiquitination peptides on 458 proteins were identified, of which 48 ubiquitination sites on 40 proteins were quantified as significantly changed after the S. eriocheiris infection. Bioinformatics analysis of ubiquitination different proteins suggested many biological process and pathways were participated in the interaction between S. eriocheiris and host cell, such as ubiquitin system, endocytosis, prophenoloxidase system (proPO system), cell apoptosis, glycolysis. Our study can enhance our understanding of interaction between the crab and S. eriocheiris, and also provides basis to study the role of protein ubiquitination in other crustacean innate immune system.
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Affiliation(s)
- Libo Hou
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Jie Du
- Animal Husbandry and Veterinary College, Jiangsu Vocational College of Agriculture and Forestry, Jurong, Jiangsu, 212400, China
| | - Qiulin Ren
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Lei Zhu
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Xianliang Zhao
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Xianghui Kong
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, 453007, China
| | - Wei Gu
- Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, 2 Xuelin Road, Nanjing, 210046, China
| | - Li Wang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, China.
| | - Qingguo Meng
- Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, 2 Xuelin Road, Nanjing, 210046, China.
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Wåhlén E, Olsson F, Söderberg O, Lennartsson J, Heldin J. Differential impact of lipid raft depletion on platelet-derived growth factor (PDGF)-induced ERK1/2 MAP-kinase, SRC and AKT signaling. Cell Signal 2022; 96:110356. [DOI: 10.1016/j.cellsig.2022.110356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/04/2022] [Accepted: 05/12/2022] [Indexed: 11/16/2022]
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Ma C, Wang C, Luo D, Yan L, Yang W, Li N, Gao N. Structural insights into the membrane microdomain organization by SPFH family proteins. Cell Res 2022; 32:176-189. [PMID: 34975153 PMCID: PMC8807802 DOI: 10.1038/s41422-021-00598-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 11/09/2021] [Indexed: 02/03/2023] Open
Abstract
The lateral segregation of membrane constituents into functional microdomains, conceptually known as lipid raft, is a universal organization principle for cellular membranes in both prokaryotes and eukaryotes. The widespread Stomatin, Prohibitin, Flotillin, and HflK/C (SPFH) family proteins are enriched in functional membrane microdomains at various subcellular locations, and therefore were hypothesized to play a scaffolding role in microdomain formation. In addition, many SPFH proteins are also implicated in highly specific processes occurring on the membrane. However, none of these functions is understood at the molecular level. Here we report the structure of a supramolecular complex that is isolated from bacterial membrane microdomains and contains two SPFH proteins (HflK and HflC) and a membrane-anchored AAA+ protease FtsH. HflK and HflC form a circular 24-mer assembly, featuring a laterally segregated membrane microdomain (20 nm in diameter) bordered by transmembrane domains of HflK/C and a completely sealed periplasmic vault. Four FtsH hexamers are embedded inside this microdomain through interactions with the inner surface of the vault. These observations provide a mechanistic explanation for the role of HflK/C and their mitochondrial homologs prohibitins in regulating membrane-bound AAA+ proteases, and suggest a general model for the organization and functionalization of membrane microdomains by SPFH proteins.
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Affiliation(s)
- Chengying Ma
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Chengkun Wang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Dingyi Luo
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Lu Yan
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Wenxian Yang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ningning Li
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319National Biomedical Imaging Center, Peking University, Beijing, China
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Li B, Qin Y, Yu X, Xu X, Yu W. Lipid raft involvement in signal transduction in cancer cell survival, cell death and metastasis. Cell Prolif 2022; 55:e13167. [PMID: 34939255 PMCID: PMC8780926 DOI: 10.1111/cpr.13167] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/08/2021] [Accepted: 11/30/2021] [Indexed: 12/19/2022] Open
Abstract
Lipid rafts are cholesterol- and sphingolipid-enriched specialized membrane domains within the plasma membrane. Lipid rafts regulate the density and activity of signal receptors by compartmentalizing them, promoting signalling cascades that play important roles in the survival, death and metastasis of cancer cells. In this review, we emphasize the current concept initially postulated by F. Mollinedo and C. Gajate on the importance of lipid rafts in cancer survival, death and metastasis by describing representative signalling pathways, including the IGF system and the PI3K/AKT, Fas/CD95, VEGF/VEGFR2 and CD44 signalling pathways, and we also discuss the concept of CASMER (cluster of apoptotic signalling molecule-enriched rafts), coined, originally introduced and further advanced by F. Mollinedo and C. Gajate in the period 2005-2010. Then, we summarize relevant research progress and suggest that lipid rafts play important roles in the survival, death and metastasis of cancer cells, making them promising targets for cancer therapy.
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Affiliation(s)
- Borui Li
- Department of Pancreatic SurgeryFudan University Shanghai Cancer CenterShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Pancreatic Cancer InstituteShanghaiChina
- Pancreatic Cancer InstituteFudan UniversityShanghaiChina
| | - Yi Qin
- Department of Pancreatic SurgeryFudan University Shanghai Cancer CenterShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Pancreatic Cancer InstituteShanghaiChina
- Pancreatic Cancer InstituteFudan UniversityShanghaiChina
| | - Xianjun Yu
- Department of Pancreatic SurgeryFudan University Shanghai Cancer CenterShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Pancreatic Cancer InstituteShanghaiChina
- Pancreatic Cancer InstituteFudan UniversityShanghaiChina
| | - Xiaowu Xu
- Department of Pancreatic SurgeryFudan University Shanghai Cancer CenterShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Pancreatic Cancer InstituteShanghaiChina
- Pancreatic Cancer InstituteFudan UniversityShanghaiChina
| | - Wenyan Yu
- Department of Pancreatic SurgeryFudan University Shanghai Cancer CenterShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Pancreatic Cancer InstituteShanghaiChina
- Pancreatic Cancer InstituteFudan UniversityShanghaiChina
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11
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Nishimura Y, Yamakawa D, Uchida K, Shiromizu T, Watanabe M, Inagaki M. Primary cilia and lipid raft dynamics. Open Biol 2021; 11:210130. [PMID: 34428960 PMCID: PMC8385361 DOI: 10.1098/rsob.210130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Primary cilia, antenna-like structures of the plasma membrane, detect various extracellular cues and transduce signals into the cell to regulate a wide range of functions. Lipid rafts, plasma membrane microdomains enriched in cholesterol, sphingolipids and specific proteins, are also signalling hubs involved in a myriad of physiological functions. Although impairment of primary cilia and lipid rafts is associated with various diseases, the relationship between primary cilia and lipid rafts is poorly understood. Here, we review a newly discovered interaction between primary cilia and lipid raft dynamics that occurs during Akt signalling in adipogenesis. We also discuss the relationship between primary cilia and lipid raft-mediated Akt signalling in cancer biology. This review provides a novel perspective on primary cilia in the regulation of lipid raft dynamics.
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Affiliation(s)
- Yuhei Nishimura
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Daishi Yamakawa
- Department of Physiology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Katsunori Uchida
- Department of Oncologic Pathology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Takashi Shiromizu
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Masatoshi Watanabe
- Department of Oncologic Pathology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Masaki Inagaki
- Department of Physiology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
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12
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Zhu J, Eid FE, Tong L, Zhao W, Wang W, Heath LS, Kang L, Cui F. Characterization of protein-protein interactions between rice viruses and vector insects. INSECT SCIENCE 2021; 28:976-986. [PMID: 32537916 DOI: 10.1111/1744-7917.12840] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Planthoppers are the most notorious rice pests, because they transmit various rice viruses in a persistent-propagative manner. Protein-protein interactions (PPIs) between virus and vector are crucial for virus transmission by vector insects. However, the number of known PPIs for pairs of rice viruses and planthoppers is restricted by low throughput research methods. In this study, we applied DeNovo, a virus-host sequence-based PPI predictor, to predict potential PPIs at a genome-wide scale between three planthoppers and five rice viruses. PPIs were identified at two different confidence thresholds, referred to as low and high modes. The number of PPIs for the five planthopper-virus pairs ranged from 506 to 1985 in the low mode and from 1254 to 4286 in the high mode. After eliminating the "one-too-many" redundant interacting information, the PPIs with unique planthopper proteins were reduced to 343-724 in the low mode and 758-1671 in the high mode. Homologous analysis showed that 11 sets and 31 sets of homologous planthopper proteins were shared by all planthopper-virus interactions in the two modes, indicating that they are potential conserved vector factors essential for transmission of rice viruses. Ten PPIs between small brown planthopper and rice stripe virus (RSV) were verified using glutathione-S-transferase (GST)/His-pull down or co-immunoprecipitation assay. Five of the ten PPIs were proven positive, and three of the five SBPH proteins were confirmed to interact with RSV. The predicted PPIs provide new clues for further studies of the complicated relationship between rice viruses and their vector insects.
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Affiliation(s)
- Junjie Zhu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | | | - Lu Tong
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Wan Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Wei Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Lenwood S Heath
- Department of Computer Science, Virginia Tech, Blacksburg, VA, United States
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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13
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Flotillin-Dependent Membrane Microdomains Are Required for Functional Phagolysosomes against Fungal Infections. Cell Rep 2021; 32:108017. [PMID: 32814035 PMCID: PMC10054021 DOI: 10.1016/j.celrep.2020.108017] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/03/2020] [Accepted: 07/17/2020] [Indexed: 11/23/2022] Open
Abstract
Lipid rafts form signaling platforms on biological membranes with incompletely characterized role in immune response to infection. Here we report that lipid-raft microdomains are essential components of phagolysosomal membranes of macrophages and depend on flotillins. Genetic deletion of flotillins demonstrates that the assembly of both major defense complexes vATPase and NADPH oxidase requires membrane microdomains. Furthermore, we describe a virulence mechanism leading to dysregulation of membrane microdomains by melanized wild-type conidia of the important human-pathogenic fungus Aspergillus fumigatus resulting in reduced phagolysosomal acidification. We show that phagolysosomes with ingested melanized conidia contain a reduced amount of free Ca2+ ions and that inhibition of Ca2+-dependent calmodulin activity led to reduced lipid-raft formation. We identify a single-nucleotide polymorphism in the human FLOT1 gene resulting in heightened susceptibility for invasive aspergillosis in hematopoietic stem cell transplant recipients. Collectively, flotillin-dependent microdomains on the phagolysosomal membrane play an essential role in protective antifungal immunity.
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14
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Song T, Hu Z, Liu J, Huang W. FLOT2 upregulation promotes growth and invasion by interacting and stabilizing EphA2 in gliomas. Biochem Biophys Res Commun 2021; 548:67-73. [PMID: 33631676 DOI: 10.1016/j.bbrc.2021.02.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 12/13/2022]
Abstract
The expression and roles of FLOT2, especially for its underlying mechanism, in gliomas have been rarely revealed. In this study, upregulations of both FLOT2 and EphA2 in gliomas tissues were validated by immunohistochemistry (IHC) staining and Western blot. FLOT2 silencing notably inhibited the growth and invasion of gliomas cells. Simultaneously, FLOT2 depletion suppressed Akt and NF-κB activities, induced apoptosis, cell cycle arrest, and epithelial-mesenchymal transition (EMT) inhibition, demonstrated by expression alterations of key proteins of the above processes. Mechanistically, FLOT2 could maintain EphA2 stability viainteraction, and restoration of EphA2 could remarkably release the suppressive effects on gliomas cells induced by FLOT2 knockdown. Lastly, FLOT2 and EphA2, whose protein and mRNA levels are both positively correlated in gliomas, shows significant association with clinical characteristics like Ki67 intensity, p53 expression, and tumor stage in patients with gliomas. In conclusion, our results reveal the upregulation, oncogenic roles of FLOT2, and the corresponding underlying mechanism in gliomas, highlighting that the FLOT2-EphA2 axis is served as a promising therapeutic target for gliomas.
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Affiliation(s)
- Tao Song
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhongxu Hu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jie Liu
- Department of Pathology, Changsha Central Hospital, Changsha, Hunan, China
| | - Wei Huang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China; Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Changsha, Hunan, China.
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15
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Nagano T, Iwasaki T, Onishi K, Awai Y, Terachi A, Kuwaba S, Asano S, Katasho R, Nagai K, Nakashima A, Kikkawa U, Kamada S. LY6D-induced macropinocytosis as a survival mechanism of senescent cells. J Biol Chem 2021; 296:100049. [PMID: 33168631 PMCID: PMC7948989 DOI: 10.1074/jbc.ra120.013500] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 10/23/2020] [Accepted: 11/09/2020] [Indexed: 01/16/2023] Open
Abstract
Although senescent cells display various morphological changes including vacuole formation, it is still unclear how these processes are regulated. We have recently identified the gene, lymphocyte antigen 6 complex, locus D (LY6D), to be upregulated specifically in senescent cells. LY6D is a glycosylphosphatidylinositol-anchored cell-surface protein whose function remains unknown. Here, we analyzed the functional relationship between LY6D and the senescence processes. We found that overexpression of LY6D induced vacuole formation and knockdown of LY6D suppressed the senescence-associated vacuole formation. The LY6D-induced vacuoles were derived from macropinocytosis, a distinct form of endocytosis. Furthermore, Src family kinases and Ras were found to be recruited to membrane lipid rafts in an LY6D-dependent manner, and inhibition of their activity impaired the LY6D-induced macropinocytosis. Finally, reduction of senescent-cell survival induced by glutamine deprivation was recovered by albumin supplementation to the culture media in an LY6D-dependent manner. Because macropinocytosis acts as an amino acid supply route, these results suggest that LY6D-mediated macropinocytosis contributes to senescent-cell survival through the incorporation of extracellular nutrients.
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Affiliation(s)
- Taiki Nagano
- Biosignal Research Center, Kobe University, Kobe, Japan
| | - Tetsushi Iwasaki
- Biosignal Research Center, Kobe University, Kobe, Japan; Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan; Department of Biology, Faculty of Science, Kobe University, Kobe, Japan
| | - Kengo Onishi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Yuto Awai
- Department of Biology, Faculty of Science, Kobe University, Kobe, Japan
| | - Anju Terachi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Shione Kuwaba
- Department of Biology, Faculty of Science, Kobe University, Kobe, Japan
| | - Shota Asano
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Ryoko Katasho
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Kiyoko Nagai
- Biosignal Research Center, Kobe University, Kobe, Japan
| | - Akio Nakashima
- Biosignal Research Center, Kobe University, Kobe, Japan; Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Ushio Kikkawa
- Biosignal Research Center, Kobe University, Kobe, Japan; Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Shinji Kamada
- Biosignal Research Center, Kobe University, Kobe, Japan; Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan; Department of Biology, Faculty of Science, Kobe University, Kobe, Japan.
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16
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Nho K, Nudelman K, Allen M, Hodges A, Kim S, Risacher SL, Apostolova LG, Lin K, Lunnon K, Wang X, Burgess JD, Ertekin-Taner N, Petersen RC, Wang L, Qi Z, He A, Neuhaus I, Patel V, Foroud T, Faber KM, Lovestone S, Simmons A, Weiner MW, Saykin AJ. Genome-wide transcriptome analysis identifies novel dysregulated genes implicated in Alzheimer's pathology. Alzheimers Dement 2020; 16:1213-1223. [PMID: 32755048 DOI: 10.1002/alz.12092] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 01/23/2020] [Accepted: 02/21/2020] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Abnormal gene expression patterns may contribute to the onset and progression of late-onset Alzheimer's disease (LOAD). METHODS We performed transcriptome-wide meta-analysis (N = 1440) of blood-based microarray gene expression profiles as well as neuroimaging and cerebrospinal fluid (CSF) endophenotype analysis. RESULTS We identified and replicated five genes (CREB5, CD46, TMBIM6, IRAK3, and RPAIN) as significantly dysregulated in LOAD. The most significantly altered gene, CREB5, was also associated with brain atrophy and increased amyloid beta (Aβ) accumulation, especially in the entorhinal cortex region. cis-expression quantitative trait loci mapping analysis of CREB5 detected five significant associations (P < 5 × 10-8 ), where rs56388170 (most significant) was also significantly associated with global cortical Aβ deposition measured by [18 F]Florbetapir positron emission tomography and CSF Aβ1-42 . DISCUSSION RNA from peripheral blood indicated a differential gene expression pattern in LOAD. Genes identified have been implicated in biological processes relevant to Alzheimer's disease. CREB, in particular, plays a key role in nervous system development, cell survival, plasticity, and learning and memory.
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Affiliation(s)
- Kwangsik Nho
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Kelly Nudelman
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.,National Centralized Repository for Alzheimer's Disease and Related Dementias, Indiana University, Indiana
| | - Mariet Allen
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida
| | - Angela Hodges
- Psychology & Neuroscience, Institute of Psychiatry, King's college London, London, UK
| | - Sungeun Kim
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Electrical and Computer Engineering, State University of New York, Oswego, New York
| | - Shannon L Risacher
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Liana G Apostolova
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Kuang Lin
- Psychology & Neuroscience, Institute of Psychiatry, King's college London, London, UK
| | | | - Xue Wang
- Department of Health Sciences Research, Mayo Clinic Florida, Jacksonville, Florida
| | - Jeremy D Burgess
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida
| | - Nilüfer Ertekin-Taner
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida.,Department of Neurology, Mayo Clinic Florida, Jacksonville, Florida
| | - Ronald C Petersen
- Department of Neurology, Mayo Clinic Minnesota, Rochester, Minnesota
| | - Lisu Wang
- Bristol-Meyers Squibb, Wallingford, Connecticut
| | - Zhenhao Qi
- Bristol-Meyers Squibb, Wallingford, Connecticut
| | - Aiqing He
- Bristol-Meyers Squibb, Wallingford, Connecticut
| | | | | | - Tatiana Foroud
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.,National Centralized Repository for Alzheimer's Disease and Related Dementias, Indiana University, Indiana
| | - Kelley M Faber
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.,National Centralized Repository for Alzheimer's Disease and Related Dementias, Indiana University, Indiana
| | | | - Andrew Simmons
- Psychology & Neuroscience, Institute of Psychiatry, King's college London, London, UK
| | - Michael W Weiner
- Departments of Radiology, Medicine, and Psychiatry, University of California-San Francisco, San Francisco, California.,Department of Veterans Affairs Medical Center, San Francisco, California
| | - Andrew J Saykin
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
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17
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Bosmani C, Leuba F, Hanna N, Bach F, Burdet F, Pagni M, Hagedorn M, Soldati T. Vacuolins and myosin VII are required for phagocytic uptake and phagosomal membrane recycling in Dictyostelium discoideum. J Cell Sci 2020; 133:jcs242974. [PMID: 32482795 DOI: 10.1242/jcs.242974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/18/2020] [Indexed: 12/17/2022] Open
Abstract
Flotillins are lipid raft residents involved in membrane trafficking and recycling of plasma membrane proteins. Dictyostelium discoideum uses phagocytosis to kill, digest and feed on bacteria. It possesses three flotillin-like vacuolins that are strongly associated with membranes and that gradually accumulate on maturing phagosomes. Absence of vacuolins reduced adhesion and particle recognition resulting in a drastic reduction in the uptake of various types of particles. This was caused by a block in the recycling of plasma membrane components and the absence of their specific cortex-associated proteins. In addition, absence of vacuolins also impaired phagolysosome biogenesis, without significantly impacting killing and digestion of a range of bacteria. Strikingly, both absence and overexpression of vacuolins induced a strong downregulation of myosin VII (also known as MyoI) expression, as well as its binding partner talin A. Episomal expression of myosin VII fully rescued defects in uptake and adhesion but not in phagosome maturation. These results suggest a dual role for vacuolins: a novel mechanism involving membrane microdomains and myosin VII-talin A in clustering phagosomal receptors and adhesion molecules at the plasma membrane, and a role in phagolysosomal biogenesis.
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Affiliation(s)
- Cristina Bosmani
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Florence Leuba
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Nabil Hanna
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
| | - Frauke Bach
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany
| | - Frédéric Burdet
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Monica Hagedorn
- Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany
| | - Thierry Soldati
- Départment de Biochimie, Faculté des Sciences, Université de Genève, CH-1205 Geneva, Switzerland
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18
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Lv D, Xiang Y, Yang Q, Yao J, Dong Q. Long Non-Coding RNA TUG1 Promotes Cell Proliferation and Inhibits Cell Apoptosis, Autophagy in Clear Cell Renal Cell Carcinoma via MiR-31-5p/FLOT1 Axis. Onco Targets Ther 2020; 13:5857-5868. [PMID: 32606796 PMCID: PMC7311099 DOI: 10.2147/ott.s254634] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/27/2020] [Indexed: 02/05/2023] Open
Abstract
Purpose Clear cell renal cell carcinoma (ccRCC) is a common urological carcinoma in adults. Long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) has been reported to be involved in the progression of diverse human cancers, including renal cell carcinoma (RCC). However, the biological mechanism of TUG1 was rarely reported in ccRCC. Methods The levels of TUG1, microRNA miR-31-5p and flotillin 1 (FLOT1) in ccRCC tissues and cells were detected by qRT-PCR. The interactions between miR-31-5p and TUG1 or FLOT1 were predicted by starBase v2.0 and TargetScan, respectively, which were further validated by RIP assay and RNA pull-down assay. Cell counting kit-8 (CCK-8), flow cytometry and Western blot were used to assess the effects of TUG1 on cell viability, apoptosis rate and the relative protein expression levels in ccRCC cells. In addition, the xenograft tumor assay was conducted to further verify the functions of TUG1 in ccRCC in vivo. Results TUG1 was dramatically up-regulated in ccRCC tissues and cells. TUG1 silencing inhibited cell proliferation and promoted cell apoptosis, autophagy in 786-0 and A498 cells. In addition, TUG1 depletion repressed tumor growth in vivo. Moreover, miR-31-5p was validated as a direct target of TUG1, and microRNA miR-31-5p inhibitor mitigated the effects of TUG1 knockdown on ccRCC progression. Furthermore, FLOT1 was verified to be negatively interacted with miR-31-5p. FLOT1 overexpression attenuated miR-31-5p-mediated inhibitory effect on cell proliferation and promotion effects on cell apoptosis, autophagy. The restoration experiment implicated that TUG1 positively modulated FLOT1 expression by sponging miR-31-5p. Conclusion All data demonstrated that TUG1 promotes cell proliferation and inhibits cell apoptosis and autophagy in ccRCC by miR-31-5p/FLOT1 axis, which may provide a therapeutic target for ccRCC patients.
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Affiliation(s)
- Dong Lv
- Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.,Department of Urology, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Ying Xiang
- Department of Urology, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Qi Yang
- Department of Urology, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Juncheng Yao
- Department of Urology, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Qiang Dong
- Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China
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19
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Badierah RA, Uversky VN, Redwan EM. Dancing with Trojan horses: an interplay between the extracellular vesicles and viruses. J Biomol Struct Dyn 2020; 39:3034-3060. [DOI: 10.1080/07391102.2020.1756409] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Raied A. Badierah
- Biological Science Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
- Molecular Diagnostic Laboratory, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vladimir N. Uversky
- Biological Science Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Federal Research Center ‘Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences’, Pushchino, Moscow Region, Russia
| | - Elrashdy M. Redwan
- Biological Science Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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20
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Lv X, Jin K, Wu Y, Zhang C, Cui S, Zhu X, Li J, Du G, Liu L. Enzyme assembly guided by SPFH-induced functional inclusion bodies for enhanced cascade biocatalysis. Biotechnol Bioeng 2020; 117:1446-1457. [PMID: 32043560 DOI: 10.1002/bit.27304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/05/2020] [Accepted: 02/09/2020] [Indexed: 01/01/2023]
Abstract
Enzyme clustering into compact agglomerates could accelerate the processing of intermediates to enhance metabolic pathway flux. However, enzyme clustering is still a challenging task due to the lack of universal assembly strategy applicable to all enzymes. Therefore, we proposed an alternative enzyme assembly strategy based on functional inclusion bodies. First, functional inclusion bodies in cells were formed by the fusion expression of stomatin/prohibitin/flotillin/HflK/C (SPFH) domain and enhanced green fluorescent protein, as observed visually and by transmission electron microscopy. The formation of SPFH-induced functional inclusion bodies enhanced intermolecular polymerization as revealed by further analysis combined with Förster resonance energy transfer and bimolecular fluorescent complimentary. Finally, the functional inclusion bodies significantly improved the enzymatic catalysis in living cells, as proven by the examples with whole-cell biocatalysis of phenyllactic acid by Escherichia coli, and the production of N-acetylglucosamine by Bacillus subtilis. Our findings suggest that SPFH-induced functional inclusion bodies can enhance the cascade reaction of enzymes, to serve as a potential universal strategy for the construction of efficient microbial cell factories.
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Affiliation(s)
- Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Ke Jin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Yaokang Wu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Cheng Zhang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Shixiu Cui
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Xiaonan Zhu
- School of Bioengineering, Jiangnan University, Wuxi, China
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Guocheng Du
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
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21
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Daněk M, Angelini J, Malínská K, Andrejch J, Amlerová Z, Kocourková D, Brouzdová J, Valentová O, Martinec J, Petrášek J. Cell wall contributes to the stability of plasma membrane nanodomain organization of Arabidopsis thaliana FLOTILLIN2 and HYPERSENSITIVE INDUCED REACTION1 proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:619-636. [PMID: 31610051 DOI: 10.1111/tpj.14566] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/11/2019] [Accepted: 09/17/2019] [Indexed: 05/24/2023]
Abstract
Current models of plasma membrane (PM) postulate its organization in various nano- and micro-domains with distinct protein and lipid composition. While metazoan PM nanodomains usually display high lateral mobility, the dynamics of plant nanodomains is often highly spatially restricted. Here we have focused on the determination of the PM distribution in nanodomains for Arabidopsis thaliana flotillin (AtFLOT) and hypersensitive induced reaction proteins (AtHIR), previously shown to be involved in response to extracellular stimuli. Using in vivo laser scanning and spinning disc confocal microscopy in Arabidopsis thaliana we present here their nanodomain localization in various epidermal cell types. Fluorescence recovery after photobleaching (FRAP) and kymographic analysis revealed that PM-associated AtFLOTs contain significantly higher immobile fraction than AtHIRs. In addition, much lower immobile fractions have been found in tonoplast pool of AtHIR3. Although members of both groups of proteins were spatially restricted in their PM distribution by corrals co-aligning with microtubules (MTs), pharmacological treatments showed no or very low role of actin and microtubular cytoskeleton for clustering of AtFLOT and AtHIR into nanodomains. Finally, pharmacological alteration of cell wall (CW) synthesis and structure resulted in changes in lateral mobility of AtFLOT2 and AtHIR1. Accordingly, partial enzymatic CW removal increased the overall dynamics as well as individual nanodomain mobility of these two proteins. Such structural links to CW could play an important role in their correct positioning during PM communication with extracellular environment.
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Affiliation(s)
- Michal Daněk
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
| | - Jindřiška Angelini
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28, Prague 6, Czech Republic
| | - Kateřina Malínská
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Jan Andrejch
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28, Prague 6, Czech Republic
| | - Zuzana Amlerová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28, Prague 6, Czech Republic
| | - Daniela Kocourková
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Jitka Brouzdová
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Olga Valentová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28, Prague 6, Czech Republic
| | - Jan Martinec
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Jan Petrášek
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
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22
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Yokoyama H, Matsui I. The lipid raft markers stomatin, prohibitin, flotillin, and HflK/C (SPFH)-domain proteins form an operon with NfeD proteins and function with apolar polyisoprenoid lipids. Crit Rev Microbiol 2020; 46:38-48. [PMID: 31983249 DOI: 10.1080/1040841x.2020.1716682] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SPFH-domain proteins are found in almost all organisms across three domains: archaea, bacteria, and eukaryotes. In eukaryotic organelles, their subfamilies exhibit overlapping distribution and functions; thus, the rationality of annotation to discriminate these subfamilies remains unclear. In this review, the binding ability of prokaryotic SPFH-domain proteins towards nonpolar polyisoprenoides such as squalene and lycopene, rather than cholesterol, is discussed. The hydrophobic region at the C-terminus of SPFH-domain proteins constitutes the main region that binds apolar polyisoprenoid lipids as well as cholesterol and substantively contributes towards lipid raft formation as these regions are self-assembled together with specific lipids. Because the scaffolding proteins caveolins show common topological properties with SPFH-domain proteins such as stomatin and flotillin, the α-helical segments of stomatin proteins can flexibly move along with the membrane surface, with such movement potentially leading to membrane bending via lipid raft clustering through the formation of high order homo-oligomeric complexes of SPFH-domain proteins. We also discuss the functional significance and ancient origin of SPFH-domain proteins and the NfeD protein (STOPP) operon, which can be traced back to the ancient living cells that diverged and evolved to archaea and bacteria. Based on the molecular mechanism whereby the STOPP-protease degrades the C-terminal hydrophobic clusters of SPFH-domain proteins, it is conceivable that STOPP-protease might control the physicochemical properties of lipid rafts.
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Affiliation(s)
- Hideshi Yokoyama
- Department of Medical and Life Sciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Ikuo Matsui
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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23
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Thalwieser Z, Király N, Fonódi M, Csortos C, Boratkó A. Protein phosphatase 2A-mediated flotillin-1 dephosphorylation up-regulates endothelial cell migration and angiogenesis regulation. J Biol Chem 2019; 294:20196-20206. [PMID: 31753918 DOI: 10.1074/jbc.ra119.007980] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Endothelial cells have key functions in endothelial barrier integrity and in responses to angiogenic signals that promote cell proliferation, cell migration, cytoskeletal reorganization, and formation of new blood vessels. These functions highly depend on protein-protein interactions in cell-cell junction and cell attachment complexes and on interactions with cytoskeletal proteins. Protein phosphatase 2A (PP2A) dephosphorylates several target proteins involved in cytoskeletal dynamics and cell adhesion. Our goal was to find new interacting and substrate proteins of the PP2A-B55α holoenzyme in bovine pulmonary endothelial cells. Using LC-MS/MS analysis, we identified flotillin-1 as a protein that binds recombinant GSH S-transferase-tagged PP2A-B55α. Immunoprecipitation experiments, proximity ligation assays, and immunofluorescent staining confirmed the interaction between these two endogenous proteins in endothelial cells. Originally, flotillins were described as regulatory proteins for axon regeneration, but they appear to function in many cellular processes, such as membrane receptor signaling, endocytosis, and cell adhesion. Ser315 is a known PKC-targeted site in flotillin-1. Utilizing phosphomutants of flotillin-1 and the NanoBiT luciferase assay, we show here that phosphorylation/dephosphorylation of Ser315 in flotillin-1 significantly affects its interaction with PP2A-B55α and that PP2A-B55α dephosphorylates phospho-Ser315 Spreading, attachment, migration, and in vitro tube formation rates of S315A variant-overexpressing cells were faster than those of nontransfected or S315D-transfected cells. These results indicate that the PP2A-flotillin-1 interaction identified here affects major physiological activities of pulmonary endothelial cells.
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Affiliation(s)
- Zsófia Thalwieser
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Nikolett Király
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Márton Fonódi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Csilla Csortos
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Anita Boratkó
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
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24
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Ficht X, Ruef N, Stolp B, Samson GPB, Moalli F, Page N, Merkler D, Nichols BJ, Diz-Muñoz A, Legler DF, Niggli V, Stein JV. In Vivo Function of the Lipid Raft Protein Flotillin-1 during CD8 + T Cell-Mediated Host Surveillance. THE JOURNAL OF IMMUNOLOGY 2019; 203:2377-2387. [PMID: 31548330 DOI: 10.4049/jimmunol.1900075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 08/24/2019] [Indexed: 01/12/2023]
Abstract
Flotillin-1 (Flot1) is an evolutionary conserved, ubiquitously expressed lipid raft-associated scaffolding protein. Migration of Flot1-deficient neutrophils is impaired because of a decrease in myosin II-mediated contractility. Flot1 also accumulates in the uropod of polarized T cells, suggesting an analogous role in T cell migration. In this study, we analyzed morphology and migration parameters of murine wild-type and Flot1-/- CD8+ T cells using in vitro assays and intravital two-photon microscopy of lymphoid and nonlymphoid tissues. Flot1-/- CD8+ T cells displayed significant alterations in cell shape and motility parameters in vivo but showed comparable homing to lymphoid organs and intact in vitro migration to chemokines. Furthermore, their clonal expansion and infiltration into nonlymphoid tissues during primary and secondary antiviral immune responses was comparable to wild-type CD8+ T cells. Taken together, Flot1 plays a detectable but unexpectedly minor role for CD8+ T cell behavior under physiological conditions.
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Affiliation(s)
- Xenia Ficht
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland
| | - Nora Ruef
- Department of Oncology, Microbiology and Immunology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Bettina Stolp
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland.,Department for Infectious Diseases, Integrative Virology, Center for Integrative Infectious Disease Research, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Guerric P B Samson
- Biotechnology Institute Thurgau at the University of Konstanz, 8280 Kreuzlingen, Switzerland
| | - Federica Moalli
- Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland.,Scientific Institute for Research and Healthcare, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Nicolas Page
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland
| | - Doron Merkler
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland
| | - Ben J Nichols
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; and
| | - Daniel F Legler
- Biotechnology Institute Thurgau at the University of Konstanz, 8280 Kreuzlingen, Switzerland
| | - Verena Niggli
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
| | - Jens V Stein
- Department of Oncology, Microbiology and Immunology, University of Fribourg, 1700 Fribourg, Switzerland;
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Lin CY, Lai HL, Chen HM, Siew JJ, Hsiao CT, Chang HC, Liao KS, Tsai SC, Wu CY, Kitajima K, Sato C, Khoo KH, Chern Y. Functional roles of ST8SIA3-mediated sialylation of striatal dopamine D 2 and adenosine A 2A receptors. Transl Psychiatry 2019; 9:209. [PMID: 31455764 PMCID: PMC6712005 DOI: 10.1038/s41398-019-0529-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/22/2019] [Accepted: 06/20/2019] [Indexed: 01/20/2023] Open
Abstract
Sialic acids are typically added to the end of glycoconjugates by sialyltransferases. Among the six ST8 α-N-acetyl-neuraminide α-2,8-sialyltransferases (ST8SIA) existing in adult brains, ST8SIA2 is a schizophrenia-associated gene. However, the in vivo substrates and physiological functions of most sialyltransferases are currently unknown. The ST8SIA3 is enriched in the striatum. Here, we showed that ablation of St8sia3 in mice (St8sia3-KO) led to fewer disialylated and trisialylated terminal glycotopes in the striatum of St8sia3-KO mice. Moreover, the apparent sizes of several striatum-enriched G-protein-coupled receptors (GPCRs) (including the adenosine A2A receptor (A2AR) and dopamine D1/D2 receptors (D1R and D2R)) were smaller in St8sia3-KO mice than in WT mice. A sialidase treatment removed the differences in the sizes of these molecules between St8sia3-KO and WT mice, confirming the involvement of sialylation. Expression of ST8SIA3 in the striatum of St8sia3-KO mice using adeno-associated viruses normalized the sizes of these proteins, demonstrating a direct role of ST8SIA3. The lack of ST8SIA3-mediated sialylation altered the distribution of these proteins in lipid rafts and the interaction between D2R and A2AR. Locomotor activity assays revealed altered pharmacological responses of St8sia3-KO mice to drugs targeting these receptors and verified that a greater population of D2R formed heteromers with A2AR in the striatum of St8sia3-KO mice. Since the A2AR-D2R heteromer is an important drug target for several basal ganglia diseases (such as schizophrenia and Parkinson's disease), the present study not only reveals a crucial role for ST8SIA3 in striatal functions but also provides a new drug target for basal ganglia-related diseases.
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Affiliation(s)
- Chien-Yu Lin
- 0000 0001 2287 1366grid.28665.3fInstitute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsing-Lin Lai
- 0000 0001 2287 1366grid.28665.3fInstitute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hui-Mei Chen
- 0000 0001 2287 1366grid.28665.3fInstitute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jian-Jing Siew
- 0000 0001 2287 1366grid.28665.3fInstitute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan ,0000 0001 0425 5914grid.260770.4Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Cheng-Te Hsiao
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hua-Chien Chang
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kuo-Shiang Liao
- 0000 0001 2287 1366grid.28665.3fGenomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Shih-Chieh Tsai
- grid.36020.37Department of Research and Development, National Laboratory Animal Center, National Applied Research Laboratories, Taipei and Tainan, Taipei, Taiwan
| | - Chung-Yi Wu
- 0000 0001 2287 1366grid.28665.3fGenomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Ken Kitajima
- 0000 0001 0943 978Xgrid.27476.30Bioscience and Biotechnology Center, Nagoya University, Nagoya, 464-860 Japan
| | - Chihiro Sato
- 0000 0001 0943 978Xgrid.27476.30Bioscience and Biotechnology Center, Nagoya University, Nagoya, 464-860 Japan
| | - Kay-Hooi Khoo
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
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26
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Dietary Fatty Acids Affect Red Blood Cell Membrane Composition and Red Blood Cell ATP Release in Dairy Cows. Int J Mol Sci 2019; 20:ijms20112769. [PMID: 31195708 PMCID: PMC6600345 DOI: 10.3390/ijms20112769] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/29/2019] [Accepted: 06/04/2019] [Indexed: 12/29/2022] Open
Abstract
Diets of dairy cows are often based on maize silage (MS), delivering lower amounts of n-3 fatty acids (FA) compared to grass silage-based diets. The fatty acid composition of the cell membrane can affect the cell function. We evaluated the effects of an MS-based diet on bovine red blood cell (RBC) membrane FA composition and dietary effects on controlled ATP release of RBC. In trial 1, German Holstein cows were fed an MS-based total mixed ration for 24 weeks. The FA composition of RBC membranes from repeatedly taken blood samples was analysed in addition to the abundance of the RBC membrane protein flotillin-1, which is involved in, for example, cell signalling. In trial 2, four rumen fistulated MS-fed cows were abomasally infused in a 4 × 4 Latin square model with three successively increasing lipid dosages (coconut oil, linseed–safflower oil mix (EFA; rich in n-3 FA), Lutalin®, providing conjugated linoleic acids (CLA) or the combination of the supplements, EFA + CLA) for six weeks, followed by a three-week washout period. In trial 2, we analysed RBC ATP release, flotillin-1, and the membrane protein abundance of pannexin-1, which is involved in ATP release as the last part of a signalling cascade. In trial 1, the total amount of n-3 FA in RBC membranes decreased and the flotillin-1 abundance increased over time. In trial 2, the RBC n-3 FA amount was higher after the six-week infusion period of EFA or EFA + CLA. Furthermore, depending on the dosage of FA, the ATP release from RBC increased. The abundance of flotillin-1 and pannexin-1 was not affected in trial 2. It is concluded that changes of the membrane FA composition influence the RBC function, leading to altered ATP release from intact bovine RBC.
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27
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Baig N, Li Z, Lu J, Chen H, Yu S, Li T, Niu Z, Niu J. Clinical significance and comparison of flotillin 1 expression in left and right colon cancer. Oncol Lett 2019; 18:997-1004. [PMID: 31423159 PMCID: PMC6607386 DOI: 10.3892/ol.2019.10401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 09/28/2018] [Indexed: 12/29/2022] Open
Abstract
Flotillin 1 (FLOT1) is increasingly implicated in various types of cancer, and has been reported to influence tumorigenesis and cancer progression, leading to poor prognosis for survival time; however, its expression in colorectal cancer (CRC) and its influence on various clinicopathological parameters of this disease remain unknown. In the present study, FLOT1 expression and its effect on different clinicopathological parameters were assessed immunohistochemically and histologically in 81 CRC and 81 non-tumorous colon tissue samples. The immunohistochemical staining was scored semi-quantitatively. The association of FLOT1 expression with various parameters and its effect on overall survival time was also assessed. FLOT1 was upregulated in the CRC tissue, with increased expression in the right colon tissue samples compared with those of left colon. Increased FLOT1 expression in CRC tissue samples was associated with tumor volume, differentiation, tumor grade and poor overall survival time. In the right colon tissue samples in particular, there was a notable association with tumor volume and grade, indicating its effect on proliferation and tumor stage at this site. A multivariate Cox regression hazard analysis revealed that only tumor grade and differentiation were the independent predictors of overall survival time in patients with CRC. Together, the results of the present study suggest that FLOT1 serves important functions in the proliferation and progression of CRC, contributes to decreased survival time, and may serve as a novel therapeutic target for the treatment of CRC.
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Affiliation(s)
- Nadia Baig
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Zequn Li
- Department of Gastrointestinal Surgery, Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
| | - Jing Lu
- Department of Chemotherapy, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Haibin Chen
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Songyang Yu
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Tianen Li
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Zhaojian Niu
- Department of Gastrointestinal Surgery, Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
| | - Jun Niu
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
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28
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Bai C, Kang N, Zhao J, Dai J, Gao H, Chen Y, Dong H, Huang C, Dong Q. Cryopreservation disrupts lipid rafts and heat shock proteins in yellow catfish sperm. Cryobiology 2019; 87:32-39. [PMID: 30876909 DOI: 10.1016/j.cryobiol.2019.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 11/25/2022]
Abstract
Lipid rafts and associated membrane proteins (flotillin, caveolin) play important roles in cell signaling and sperm fertilization while heat shock proteins (Hsp) ensure properly protein folding to fulfill their physiological functions. The markedly reduced fertility in thawed sperm after cryopreservation could result from disrupted membrane lipid rafts and these proteins. To explore the effect of sperm cryopreservation on lipid rafts and heat shock proteins, we compared lipid raft integrity, and the expression levels of lipid raft associated proteins (Flot-1, Flot-2, Cav-1) as well as heat shock proteins (Hsp90, Hsp70) in fresh and thawed sperm cryopreserved under different scenarios in yellow catfish. We found higher lipid raft integrity, higher protein expression levels of Flot-1, Flot-2, Cav-1, Hsp90, and Hsp70 in fresh sperm samples than in thawed sperm samples, in thawed sperm samples cryopreserved with optimal cooling rate than those cryopreserved with sub-optimal cooling rate, and in thawed sperm samples cryopreserved with extenders supplemented with cholesterol than those supplemented with methyl-β-cyclodextrin (for cholesterol removal). Our findings indicate that lipid raft integrity, and expression levels of Flot-1, Flot-2, Cav-1, Hsp90, and Hsp70 are clearly associated with sperm quality, and together they may play a cumulative role in reduced fertility associated with thawed sperm in aquatic species.
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Affiliation(s)
- Chenglian Bai
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325035, PR China; Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Ning Kang
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Junping Zhao
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Jun Dai
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Hui Gao
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325035, PR China; Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Yuanhong Chen
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Haojia Dong
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Changjiang Huang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325035, PR China; Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Qiaoxiang Dong
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325035, PR China; Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou 325035, PR China.
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29
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Individual differences in EPA and DHA content of Atlantic salmon are associated with gene expression of key metabolic processes. Sci Rep 2019; 9:3889. [PMID: 30846825 PMCID: PMC6405848 DOI: 10.1038/s41598-019-40391-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/14/2019] [Indexed: 12/12/2022] Open
Abstract
The aim of this study was to explore how individual differences in content of the omega-3 fatty acids EPA and DHA in skeletal muscle of slaughter-sized Atlantic salmon, are associated with expression of genes involved in key metabolic processes. All experimental fish were fed the same diet throughout life and fasted for 14 days prior to slaughter. Still, there were relatively large individual variations in EPA and DHA content of skeletal muscle. Higher DHA content was concurrent with increased expression of genes of the glycolytic pathway and the production of pyruvate and lactate, whereas EPA was associated with increased expression of pentose phosphate pathway and glycogen breakdown genes. Furthermore, EPA, but not DHA, was associated with expression of genes involved in insulin signaling. Expression of genes specific for skeletal muscle function were positively associated with both EPA and DHA. EPA and DHA were also associated with expression of genes related to eicosanoid and resolvin production. EPA was negatively associated with expression of genes involved in lipid catabolism. Thus, a possible reason why some individuals have a higher level of EPA in the skeletal muscle is that they deposit - rather than oxidize - EPA for energy.
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30
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Insufficient radiofrequency ablation promotes the metastasis of residual hepatocellular carcinoma cells via upregulating flotillin proteins. J Cancer Res Clin Oncol 2019; 145:895-907. [PMID: 30820716 PMCID: PMC6435628 DOI: 10.1007/s00432-019-02852-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 01/24/2019] [Indexed: 12/27/2022]
Abstract
Purpose Radiofrequency ablation (RFA) therapy has proven to be effective and feasible for early-stage hepatocellular carcinoma (HCC); however, rapid progression of residual tumor cells after RFA has been confirmed, but the molecular mechanisms of this phenomenon are poorly understood. This study evaluated the effect of the lipid raft proteins known as flotillins on the invasive and metastatic potential of residual HCC. Methods The human HCC cell line HCCLM3 was used to establish insufficient RFA models in vivo and in vitro. Changes in cellular morphology, soft agar colony formation, motility, metastasis, and epithelial–mesenchymal transition (EMT) markers after insufficient RFA intervention in vitro and in vivo were detected by real-time PCR, western blotting, immunohistochemistry and transwell assays. Results The results showed that flotillin-1 and flotillin-2 expression were upregulated in HCCLM3 cells following 45 °C heat treatment and in residual HCCLM3 xenografts cells after insufficient RFA. Knocking down flotillin-1 or flotillin-2 in HCCLM3 cells by shRNA significantly lowered insufficient RFA-induced tumor growth, EMT changes, and metastasis in vitro and in vivo. Furthermore, mechanism studies indicated that flotillins altered the EMT status and metastatic potential of heat-treated HCCLM3 cells by activating the Akt/Wnt/β-catenin signaling pathway. Conclusions Our findings present new evidence that flotillins play a key role in the aggressive behaviors of residual cancer cells after insufficient RFA and provide new insights into the regulatory mechanism of Wnt/β-catenin signaling. Electronic supplementary material The online version of this article (10.1007/s00432-019-02852-z) contains supplementary material, which is available to authorized users.
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31
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Li T, Cao C, Xiong Q, Liu D. FLOT2 overexpression is associated with the progression and prognosis of human colorectal cancer. Oncol Lett 2019; 17:2802-2808. [PMID: 30854055 PMCID: PMC6365903 DOI: 10.3892/ol.2019.9882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
Altered expression of flotillin-2 (FLOT2) has been identified in certain types of cancer, including breast cancer and melanoma; however, to the best of our knowledge, the association between the FLOT2 expression level and colorectal cancer (CRC) remains to be determined. The aim of the present study was to investigate the clinical and prognostic significance of FLOT2 in CRC. The expression of FLOT2 was determined in seven CRC cell lines and one normal colon cell line, and it was identified that FLOT2 was increased in CRC cell lines, suggesting that FLOT2 exhibited an association with CRCs. In addition, FLOT2 protein levels were investigated in primary CRC tissues and corresponding non-cancerous colon tissues from 8 patients. Compared with non-cancerous tissues, FLOT2 protein was apparently upregulated in CRC tissues. To validate this result, an immunohistochemistry assay was performed and it was identified that FLOT2 levels were increased in CRC tissues. Clinical analysis identified that increased expression of FLOT2 was associated with the depth of invasion, lymph node metastasis, distant metastasis and American Joint Committee on Cancer stage of CRCs. Furthermore, multivariate analysis using the Cox regression model indicated that increased FLOT2 expression was an independent prognostic factor in patients with CRC (P=0.013). Taken together, the results of the present study suggest that overexpression of FLOT2 contributes to the progression of CRC and indicate that FLOT2 is a novel target for the treatment of CRC.
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Affiliation(s)
- Taiyuan Li
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Chuanlin Cao
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Qiangqiang Xiong
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Dongning Liu
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
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Rudd AK, Brea RJ, Devaraj NK. Amphiphile-Mediated Depalmitoylation of Proteins in Living Cells. J Am Chem Soc 2018; 140:17374-17378. [PMID: 30516377 DOI: 10.1021/jacs.8b10806] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Post-translational S-palmitoylation plays a central role in protein localization, trafficking, stability, aggregation, and cell signaling. Dysregulation of palmitoylation pathways in cells can alter protein function and is the cause of several diseases. Considering the biological and clinical importance of S-palmitoylation, tools for direct, in vivo modulation of this lipid modification would be extremely valuable. Here, we describe a method for the cleavage of native S-palmitoyl groups from proteins in living cells. Using a cell permeable, cysteine-functionalized amphiphile, we demonstrate the direct depalmitoylation of cellular proteins. We show that amphiphile-mediated depalmitoylation (AMD) can effectively cleave S-palmitoyl groups from the native GTPase HRas and successfully depalmitoylate mislocalized proteins in an infantile neuronal ceroid lipofuscinosis (INCL) disease model. AMD enables direct and facile depalmitoylation of proteins in live cells and has potential therapeutic applications for diseases such as INCL, where native protein thioesterase activity is deficient.
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Affiliation(s)
- Andrew K Rudd
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Roberto J Brea
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Neal K Devaraj
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
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Kessler EL, van Stuijvenberg L, van Bavel JJA, van Bennekom J, Zwartsen A, Rivaud MR, Vink A, Efimov IR, Postma AV, van Tintelen JP, Remme CA, Vos MA, Banning A, de Boer TP, Tikkanen R, van Veen TAB. Flotillins in the intercalated disc are potential modulators of cardiac excitability. J Mol Cell Cardiol 2018; 126:86-95. [PMID: 30452906 DOI: 10.1016/j.yjmcc.2018.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 01/24/2023]
Abstract
BACKGROUND The intercalated disc (ID) is important for cardiac remodeling and has become a subject of intensive research efforts. However, as yet the composition of the ID has still not been conclusively resolved and the role of many proteins identified in the ID, like Flotillin-2, is often unknown. The Flotillin proteins are known to be involved in the stabilization of cadherins and desmosomes in the epidermis and upon cancer development. However, their role in the heart has so far not been investigated. Therefore, in this study, we aimed at identifying the role of Flotillin-1 and Flotillin-2 in the cardiac ID. METHODS Location of Flotillins in human and murine cardiac tissue was evaluated by fluorescent immunolabeling and co-immunoprecipitation. In addition, the effect of Flotillin knockout (KO) on proteins of the ID and in electrical excitation and conduction was investigated in cardiac samples of wildtype (WT), Flotillin-1 KO, Flotilin-2 KO and Flotilin-1/2 double KO mice. Consequences of Flotillin knockdown (KD) on cardiac function were studied (patch clamp and Multi Electrode Array (MEA)) in neonatal rat cardiomyocytes (NRCMs) transfected with siRNAs against Flotillin-1 and/or Flotillin-2. RESULTS First, we confirmed presence in the ID and mutual binding of Flotillin-1 and Flotillin-2 in murine and human cardiac tissue. Flotillin KO mice did not show cardiac fibrosis, nor hypertrophy or changes in expression of the desmosomal ID proteins. However, protein expression of the cardiac sodium channel NaV1.5 was significantly decreased in Flotillin-1 and Flotillin-1/2 KO mice compared to WT mice. In addition, sodium current density showed a significant decrease upon Flotillin-1/2 KD in NRCMs as compared to scrambled siRNA-transfected NRCMs. MEA recordings of Flotillin-2 KD NRCM cultures showed a significantly decreased spike amplitude and a tendency of a reduced spike slope when compared to control and scrambled siRNA-transfected cultures. CONCLUSIONS In this study, we demonstrate the presence of Flotillin-1, in addition to Flotillin-2 in the cardiac ID. Our findings indicate a modulatory role of Flotillins on NaV1.5 expression at the ID, with potential consequences for cardiac excitation.
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Affiliation(s)
- Elise L Kessler
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Leonie van Stuijvenberg
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Joanne J A van Bavel
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Joëlle van Bennekom
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Anne Zwartsen
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands; Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Mathilde R Rivaud
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Aryan Vink
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Alex V Postma
- Department of Clinical Genetics, Amsterdam University Medical Center, Location AMC, the Netherlands
| | - J Peter van Tintelen
- Department of Clinical Genetics, Amsterdam University Medical Center, Location AMC, the Netherlands; Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Carol A Remme
- Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, the Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Germany
| | - Teun P de Boer
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Germany
| | - Toon A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
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Petrova V, Eva R. The Virtuous Cycle of Axon Growth: Axonal Transport of Growth-Promoting Machinery as an Intrinsic Determinant of Axon Regeneration. Dev Neurobiol 2018; 78:898-925. [PMID: 29989351 DOI: 10.1002/dneu.22608] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 02/02/2023]
Abstract
Injury to the brain and spinal cord has devastating consequences because adult central nervous system (CNS) axons fail to regenerate. Injury to the peripheral nervous system (PNS) has a better prognosis, because adult PNS neurons support robust axon regeneration over long distances. CNS axons have some regenerative capacity during development, but this is lost with maturity. Two reasons for the failure of CNS regeneration are extrinsic inhibitory molecules, and a weak intrinsic capacity for growth. Extrinsic inhibitory molecules have been well characterized, but less is known about the neuron-intrinsic mechanisms which prevent axon re-growth. Key signaling pathways and genetic/epigenetic factors have been identified which can enhance regenerative capacity, but the precise cellular mechanisms mediating their actions have not been characterized. Recent studies suggest that an important prerequisite for regeneration is an efficient supply of growth-promoting machinery to the axon; however, this appears to be lacking from non-regenerative axons in the adult CNS. In the first part of this review, we summarize the evidence linking axon transport to axon regeneration. We discuss the developmental decline in axon regeneration capacity in the CNS, and comment on how this is paralleled by a similar decline in the selective axonal transport of regeneration-associated receptors such as integrins and growth factor receptors. In the second part, we discuss the mechanisms regulating selective polarized transport within neurons, how these relate to the intrinsic control of axon regeneration, and whether they can be targeted to enhance regenerative capacity. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000-000, 2018.
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Affiliation(s)
- Veselina Petrova
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 OPY, United Kingdom
| | - Richard Eva
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 OPY, United Kingdom
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Santos AL, Preta G. Lipids in the cell: organisation regulates function. Cell Mol Life Sci 2018; 75:1909-1927. [PMID: 29427074 PMCID: PMC11105414 DOI: 10.1007/s00018-018-2765-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/04/2018] [Accepted: 01/29/2018] [Indexed: 12/19/2022]
Abstract
Lipids are fundamental building blocks of all cells and play important roles in the pathogenesis of different diseases, including inflammation, autoimmune disease, cancer, and neurodegeneration. The lipid composition of different organelles can vary substantially from cell to cell, but increasing evidence demonstrates that lipids become organised specifically in each compartment, and this organisation is essential for regulating cell function. For example, lipid microdomains in the plasma membrane, known as lipid rafts, are platforms for concentrating protein receptors and can influence intra-cellular signalling. Lipid organisation is tightly regulated and can be observed across different model organisms, including bacteria, yeast, Drosophila, and Caenorhabditis elegans, suggesting that lipid organisation is evolutionarily conserved. In this review, we summarise the importance and function of specific lipid domains in main cellular organelles and discuss recent advances that investigate how these specific and highly regulated structures contribute to diverse biological processes.
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Affiliation(s)
- Ana L Santos
- Institut National de la Santé et de la Recherche Médicale, U1001 and Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Giulio Preta
- Institute of Biochemistry, Vilnius University, Sauletekio 7, LT-10257, Vilnius, Lithuania.
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Lu SM, Fairn GD. Mesoscale organization of domains in the plasma membrane - beyond the lipid raft. Crit Rev Biochem Mol Biol 2018; 53:192-207. [PMID: 29457544 DOI: 10.1080/10409238.2018.1436515] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The plasma membrane is compartmentalized into several distinct regions or domains, which show a broad diversity in both size and lifetime. The segregation of lipids and membrane proteins is thought to be driven by the lipid composition itself, lipid-protein interactions and diffusional barriers. With regards to the lipid composition, the immiscibility of certain classes of lipids underlies the "lipid raft" concept of plasmalemmal compartmentalization. Historically, lipid rafts have been described as cholesterol and (glyco)sphingolipid-rich regions of the plasma membrane that exist as a liquid-ordered phase that are resistant to extraction with non-ionic detergents. Over the years the interest in lipid rafts grew as did the challenges with studying these nanodomains. The term lipid raft has fallen out of favor with many scientists and instead the terms "membrane raft" or "membrane nanodomain" are preferred as they connote the heterogeneity and dynamic nature of the lipid-protein assemblies. In this article, we will discuss the classical lipid raft hypothesis and its limitations. This review will also discuss alternative models of lipid-protein interactions, annular lipid shells, and larger membrane clusters. We will also discuss the mesoscale organization of plasmalemmal domains including visible structures such as clathrin-coated pits and caveolae.
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Affiliation(s)
- Stella M Lu
- a Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto , Canada.,b Department of Biochemistry , University of Toronto , Toronto , Canada
| | - Gregory D Fairn
- a Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto , Canada.,b Department of Biochemistry , University of Toronto , Toronto , Canada.,c Department of Surgery , University of Toronto , Toronto , Canada
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Mielich-Süss B, Wagner RM, Mietrach N, Hertlein T, Marincola G, Ohlsen K, Geibel S, Lopez D. Flotillin scaffold activity contributes to type VII secretion system assembly in Staphylococcus aureus. PLoS Pathog 2017; 13:e1006728. [PMID: 29166667 PMCID: PMC5718613 DOI: 10.1371/journal.ppat.1006728] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 12/06/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
Scaffold proteins are ubiquitous chaperones that promote efficient interactions between partners of multi-enzymatic protein complexes; although they are well studied in eukaryotes, their role in prokaryotic systems is poorly understood. Bacterial membranes have functional membrane microdomains (FMM), a structure homologous to eukaryotic lipid rafts. Similar to their eukaryotic counterparts, bacterial FMM harbor a scaffold protein termed flotillin that is thought to promote interactions between proteins spatially confined to the FMM. Here we used biochemical approaches to define the scaffold activity of the flotillin homolog FloA of the human pathogen Staphylococcus aureus, using assembly of interacting protein partners of the type VII secretion system (T7SS) as a case study. Staphylococcus aureus cells that lacked FloA showed reduced T7SS function, and thus reduced secretion of T7SS-related effectors, probably due to the supporting scaffold activity of flotillin. We found that the presence of flotillin mediates intermolecular interactions of T7SS proteins. We tested several small molecules that interfere with flotillin scaffold activity, which perturbed T7SS activity in vitro and in vivo. Our results suggest that flotillin assists in the assembly of S. aureus membrane components that participate in infection and influences the infective potential of this pathogen. The recently discovered functional membrane microdomains (FMM) of prokaryotic cells contain a protein homologous to the scaffold protein flotillin found in eukaryotic lipid rafts. It remains to be elucidated whether, like their eukaryotic counterparts, flotillin homolog proteins have a scaffold function in bacteria. Here we show that the Staphylococcus aureus flotillin FloA acts as a scaffold protein, to promote more efficient assembly of membrane-associated protein interacting partners of multi-enzyme complexes. In a case study, we provide biochemical evidence that FloA participates in assembly of the Type VII secretion system and thus contributes to S. aureus infective potential. Targeted dispersion of FMM-related processes using anti-FMM molecules opens up new perspectives for microbial therapies to treat persistent S. aureus infections.
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Affiliation(s)
- Benjamin Mielich-Süss
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
| | - Rabea M. Wagner
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
- National Center for Biotechnology, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Nicole Mietrach
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
- Rudolf Virchow Center - DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Tobias Hertlein
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
| | - Gabriella Marincola
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
| | - Knut Ohlsen
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
| | - Sebastian Geibel
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
- Rudolf Virchow Center - DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Daniel Lopez
- Research Center for Infectious Diseases ZINF, University of Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology IMIB, University of Würzburg, Würzburg, Germany
- National Center for Biotechnology, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
- * E-mail:
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Chen K, Wu Q, Hu K, Yang C, Wu X, Cheung P, Williams KJ. Suppression of Hepatic FLOT1 (Flotillin-1) by Type 2 Diabetes Mellitus Impairs the Disposal of Remnant Lipoproteins via Syndecan-1. Arterioscler Thromb Vasc Biol 2017; 38:102-113. [PMID: 29162604 DOI: 10.1161/atvbaha.117.310358] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 11/07/2017] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Type 2 diabetes mellitus (T2DM) and the atherometabolic syndrome exhibit a deadly dyslipoproteinemia that arises in part from impaired hepatic disposal of C-TRLs (cholesterol- and triglyceride-rich remnant apoB [apolipoprotein B] lipoproteins). We previously identified syndecan-1 as a receptor for C-TRLs that directly mediates endocytosis via rafts, independent from coated pits. Caveolins and flotillins form rafts but facilitate distinct endocytotic pathways. We now investigated their participation in syndecan-1-mediated disposal of C-TRLs and their expression in T2DM liver. APPROACH AND RESULTS In cultured liver cells and nondiabetic murine livers, we found that syndecan-1 coimmunoprecipitates with FLOT1 (flotillin-1) but not with CAV1 (caveolin-1). Binding of C-TRLs to syndecan-1 on the surface of liver cells enhanced syndecan-1/FLOT1 association. The 2 molecules then trafficked together into the lysosomes, implying limited if any recycling back to the cell surface. The interaction requires the transmembrane/cytoplasmic region of syndecan-1 and the N-terminal hydrophobic domain of FLOT1. Knockdown of FLOT1 in cultured liver cells substantially inhibited syndecan-1 endocytosis. Livers from obese, T2DM KKAy mice exhibited 60% to 70% less FLOT1 protein and mRNA than in nondiabetic KK livers. An adenoviral construct to enhance hepatic expression of wild-type FLOT1 in T2DM mice normalized plasma triglycerides, whereas a mutant FLOT1 missing its N-terminal hydrophobic domain had no effect. Moreover, the adenoviral vector for wild-type FLOT1 lowered plasma triglyceride excursions and normalized retinyl excursions in T2DM KKAy mice after a corn oil gavage, without affecting postprandial production of C-TRLs. CONCLUSIONS FLOT1 is a novel participant in the disposal of harmful C-TRLs via syndecan-1. Low expression of FLOT1 in T2DM liver may contribute to metabolic dyslipoproteinemia.
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Affiliation(s)
- Keyang Chen
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.).
| | - Qingsi Wu
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.)
| | - Kongwang Hu
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.)
| | - Chengwei Yang
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.)
| | - Xiangdong Wu
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.)
| | - Peter Cheung
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.)
| | - Kevin Jon Williams
- From the School of Public Health (K.C., Q.W., C.Y.) and Department of Surgery, The First Affiliated Hospital (K.H.), Anhui Medical University, Hefei, China; Section of Endocrinology, Diabetes, & Metabolism, Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (K.C., X.W., P.C., K.J.W.); and Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Sweden (K.J.W.).
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Koch G, Wermser C, Acosta IC, Kricks L, Stengel ST, Yepes A, Lopez D. Attenuating Staphylococcus aureus Virulence by Targeting Flotillin Protein Scaffold Activity. Cell Chem Biol 2017; 24:845-857.e6. [PMID: 28669526 DOI: 10.1016/j.chembiol.2017.05.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/11/2017] [Accepted: 05/30/2017] [Indexed: 01/13/2023]
Abstract
Scaffold proteins are ubiquitous chaperones that bind proteins and facilitate physical interaction of multi-enzyme complexes. Here we used a biochemical approach to dissect the scaffold activity of the flotillin-homolog protein FloA of the multi-drug-resistant human pathogen Staphylococcus aureus. We show that FloA promotes oligomerization of membrane protein complexes, such as the membrane-associated RNase Rny, which forms part of the RNA-degradation machinery called the degradosome. Cells lacking FloA had reduced Rny function and a consequent increase in the targeted sRNA transcripts that negatively regulate S. aureus toxin expression. Small molecules that altered FloA oligomerization also reduced Rny function and decreased the virulence potential of S. aureus in vitro, as well as in vivo, using invertebrate and murine infection models. Our results suggest that flotillin assists in the assembly of protein complexes involved in S. aureus virulence, and could thus be an attractive target for the development of new antimicrobial therapies.
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Affiliation(s)
- Gudrun Koch
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Charlotte Wermser
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Ivan C Acosta
- National Centre for Biotechnology (CNB), Spanish Research Council (CSIC), Darwin 3, Madrid 28049, Spain
| | - Lara Kricks
- National Centre for Biotechnology (CNB), Spanish Research Council (CSIC), Darwin 3, Madrid 28049, Spain
| | - Stephanie T Stengel
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Ana Yepes
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Daniel Lopez
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany; National Centre for Biotechnology (CNB), Spanish Research Council (CSIC), Darwin 3, Madrid 28049, Spain.
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40
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Liang Z, Wang X, Xu X, Xie B, Ji A, Meng S, Li S, Zhu Y, Wu J, Hu Z, Lin Y, Zheng X, Xie L, Liu B. MicroRNA-608 inhibits proliferation of bladder cancer via AKT/FOXO3a signaling pathway. Mol Cancer 2017; 16:96. [PMID: 28549468 PMCID: PMC5446711 DOI: 10.1186/s12943-017-0664-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/18/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Current evidence indicates that miR-608 is widely down-regulated in various malignant tumors including liver cancer, colon cancer, lung cancer and glioma, and acts as a tumor suppressor by inhibiting cell proliferation, invasion and migration or by promoting apoptosis. The specific biological function of miR-608 in bladder cancer is still unknown. METHODS qRT-PCR and Chromogenic in Situ Hybridization (CISH) was conducted to assess the expression of miR-608 in paired BCa tissues and adjacent non-tumor bladder urothelial tissues. Bisulfite sequencing PCR was used for DNA methylation analysis. CCK-8, colony formation and flow cytometry assays were performed, and a xenograft model was studied. Immunohistochemistry staining was performed with peroxidase and DAB. The target of miR-608 was validated with a dual-luciferase reporter assay, quantitative RT-PCR, and Western blotting. RESULTS miR-608 is frequently down-regulated in human BCa tissues. The methylation status of CpG islands is involved in the regulation of miR-608 expression. Overexpression of miR-608 inhibits the proliferation and tumorigenesis of BCa cells in vitro and in vivo. Additionally, up-regulation of miR-608 in BCa cells induces G1-phase arrest through AKT/FOXO3a signaling. In contrast, down-regulation of miR-608 promotes proliferation and cell cycle progression in BCa cells. Moreover, the expression of FLOT1 was directly inhibited by miR-608, the down-regulation of FLOT1 induced by siFLOT1 could be significantly reversed by miR-608 inhibitor. Similarly, the up-regulation of FLOT1 by FLOT1 overexpression plasmid (pFLOT1) could also reverse the suppressed cell proliferation caused by miR-608. CONCLUSIONS miR-608 is a potential tumor suppressor in BCa, and the restoration of miR-608 might be a promising therapeutic option for BCa.
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Affiliation(s)
- Zhen Liang
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Xiao Wang
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Xin Xu
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Bo Xie
- Department of Urology, TongDe Hospital of Zhejiang Province, Hangzhou, China
| | - Alin Ji
- Department of Urology, Zhejiang Provincial People’s Hospital, Hangzhou, China
| | - Shuai Meng
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Shiqi Li
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Yi Zhu
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Jian Wu
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Zhenghui Hu
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Yiwei Lin
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Xiangyi Zheng
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Liping Xie
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
| | - Ben Liu
- Department of Urology, the First Affiliated Hospital, Zhejiang University, School of Medicine, 79, Qingchun Road, 310003 Hangzhou, Zhejiang China
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Wei G, Xu Y, Peng T, Yan J. miR-133 involves in lung adenocarcinoma cell metastasis by targeting FLOT2. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 46:224-230. [PMID: 28503944 DOI: 10.1080/21691401.2017.1324467] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Dysregulated microRNAs (miRNAs) reported to involve into the oncogenesis and progression in various human cancers. However, the roles and mechanism of miR-133 in lung adenocarcinoma remain largely unclear. METHODS In this study, qPCR assay and western blot were used to detect the expression levels of miR-133, Akt and FLOT2. Luciferase reporter assay was used to identify the target role of miR-133 on FLOT2. The cell invasion and the migration capability were performed using the transwell invasion assay and wound healing assay. RESULTS We found that miR-133 expression levels were downregulated in human lung adenocarcinoma specimens and cell lines compared with the adjacent normal tissues and normal human bronchial epithelial cell. miR-133 significantly suppressed metastasis of lung adenocarcinoma cells in vitro. Furthermore, FLOT2 (flotillin-2) identified as a direct target of miR-133, and FLOT2 expression levels were inversely correlated with miR-133 expression levels in human lung adenocarcinoma specimens. And the restoration studies suggested FGF2 as a downstream effector of miR-133 which acted through Akt signalling pathway. CONCLUSIONS Our study revealed the mechanism that miR-133 suppresses lung adenocarcinoma metastasis by targeting FLOT2 via Akt signalling pathway, implicating a potential prognostic biomarker and therapeutic target for lung adenocarcinoma treatment.
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Affiliation(s)
- Guangxia Wei
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Yahuan Xu
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Tao Peng
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
| | - Jie Yan
- a Department of Cardiothoracic Surgery , Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group , Huangshi , Hubei Province , China
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42
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Calpain inhibition prevents flotillin re-ordering and Src family activation during capacitation. Cell Tissue Res 2017; 369:395-412. [DOI: 10.1007/s00441-017-2591-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/17/2017] [Indexed: 01/08/2023]
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43
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Ou YX, Liu FT, Chen FY, Zhu ZM. Prognostic value of Flotillin-1 expression in patients with solid tumors. Oncotarget 2017; 8:52665-52677. [PMID: 28881760 PMCID: PMC5581059 DOI: 10.18632/oncotarget.17075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/16/2017] [Indexed: 12/01/2022] Open
Abstract
Background In numerous studies, Flotillin-1 was reported to be involved in tumor progression, indicating prognosis in various types of cancer. However, the results were inconsistent. Results A total of 2473 patients from 13 articles were included. The results indicated that: (1) Patients detected with high expression level of Flotillin-1 protein had a significantly shorter OS (HR =1.64; 95%CI: 1.39-1.88), statistical significance was also observed in subgroup meta-analyses stratified by the cancer type, nationality, detecting method, cutoff value, analysis type, sample size and publication date. (2) Patients with high Flotillin-1 protein expression level had a poorer DFS (HR = 2.49; 95%CI: 1.64-3.35), a worse RFS(HR = 3.26; 95%CI: 1.10-5.43) and a potential shorter PFS(HR = 1.84; 95%CI: 0.81-2.87). (3) The pooled odds ratios (ORs) showed that increased Flotillin-1 level was also related to lymph node metastasis (OR =6.30; 95% CI: 3.15-12.59), distant metastasis (OR =6.02; 95% CI: 1.50-24.06) and more advanced TNM stage (OR =4.69; 95% CI: 2.74-8.03). Materials and methods A comprehensive retrieval was performed in multiple databases, including PubMed, Embase, Web of Science and CNKI. The relevant articles were screened for investigating the association between increased Flotillin-1 expression level and prognosis. Additionally, clinicopathological features data was also extracted from these studies. Conclusions High expression level of Flotillin-1 protein was correlated with poorer clinical outcome. It might serve as a prognostic biomarker and a potential predictive factor of clinicopathology in various tumors. Further well-designed clinical studies should be performed to verify the clinical utility of Flotillin-1 in human solid tumors.
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Affiliation(s)
- Yang-Xi Ou
- Department of General Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330000, Jiangxi Province, P. R. China
| | - Fang-Teng Liu
- Department of General Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330000, Jiangxi Province, P. R. China.,Jiangxi Medical College, Nanchang University, Nanchang 330006, Jiangxi Province, P. R. China
| | - Fang-Ying Chen
- The Health Centers of Fengzhou Town, Quanzhou 36200, Fujian Province, P. R. China
| | - Zheng-Ming Zhu
- Department of General Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330000, Jiangxi Province, P. R. China
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Lopez D, Koch G. Exploring functional membrane microdomains in bacteria: an overview. Curr Opin Microbiol 2017; 36:76-84. [PMID: 28237903 DOI: 10.1016/j.mib.2017.02.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/01/2017] [Indexed: 01/08/2023]
Abstract
Recent studies show that internal organization of bacterial cells is more complex than previously appreciated. A clear example of this is the assembly of the nanoscale membrane platforms termed functional membrane microdomains. The lipid composition of these regions differs from that of the surrounding membrane; these domains confine a set of proteins involved in specific cellular processes such as protease secretion and signal transduction. It is currently thought that functional membrane microdomains act as oligomerization platforms and promote efficient oligomerization of interacting protein partners in bacterial membranes. In this review, we highlight the most noteworthy achievements, challenges and controversies of this emerging research field over the past five years.
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Affiliation(s)
- Daniel Lopez
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany; Spanish National Centre for Biotechnology (CNB), Madrid 28049, Spain.
| | - Gudrun Koch
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany; Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
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45
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MiR-485 inhibits metastasis and EMT of lung adenocarcinoma by targeting Flot2. Biochem Biophys Res Commun 2016; 477:521-526. [DOI: 10.1016/j.bbrc.2016.04.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/09/2016] [Indexed: 01/24/2023]
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Functional Membrane Microdomains Organize Signaling Networks in Bacteria. J Membr Biol 2016; 250:367-378. [PMID: 27566471 DOI: 10.1007/s00232-016-9923-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 08/16/2016] [Indexed: 11/27/2022]
Abstract
Membrane organization is usually associated with the correct function of a number of cellular processes in eukaryotic cells as diverse as signal transduction, protein sorting, membrane trafficking, or pathogen invasion. It has been recently discovered that bacterial membranes are able to compartmentalize their signal transduction pathways in functional membrane microdomains (FMMs). In this review article, we discuss the biological significance of the existence of FMMs in bacteria and comment on possible beneficial roles that FMMs play on the harbored signal transduction cascades. Moreover, four different membrane-associated signal transduction cascades whose functions are linked to the integrity of FMMs are introduced, and the specific role that FMMs play in stabilizing and promoting interactions of their signaling components is discussed. Altogether, FMMs seem to play a relevant role in promoting more efficient activation of signal transduction cascades in bacterial cells and show that bacteria are more sophisticated organisms than previously appreciated.
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Dempwolff F, Schmidt FK, Hervás AB, Stroh A, Rösch TC, Riese CN, Dersch S, Heimerl T, Lucena D, Hülsbusch N, Stuermer CAO, Takeshita N, Fischer R, Eckhardt B, Graumann PL. Super Resolution Fluorescence Microscopy and Tracking of Bacterial Flotillin (Reggie) Paralogs Provide Evidence for Defined-Sized Protein Microdomains within the Bacterial Membrane but Absence of Clusters Containing Detergent-Resistant Proteins. PLoS Genet 2016; 12:e1006116. [PMID: 27362352 PMCID: PMC4928834 DOI: 10.1371/journal.pgen.1006116] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 05/20/2016] [Indexed: 12/14/2022] Open
Abstract
Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro—and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds. Many membrane proteins are not uniformly distributed within biological membranes, and may prefer specific lipid environments to function optimally. Using super resolution fluorescence microscopy, we show that several Bacillus subtilis membrane proteins indeed cluster into structures of 60 to 110 nm, verifying the existence of defined-size protein microdomains. Biochemical co-isolation of specific membrane proteins and flotillins, a family of proteins highly conserved between eukaryotic and bacterial cells, suggested that common “functional” microdomains exist, containing so-called “detergent-resistant” membrane proteins, that are centered by flotillins. Through high speed tracking of Bacillus subtilis FloA and FloT we show that both proteins are not present in the same microdomain, but move through the membrane with different velocities. Dual colour time lapse microscopy showed that contrarily to vertebrate flotillins, bacterial flotillins do not move together with detergent-resistant proteins, ruling out the existence of coclusters. The lack of both flotillins, but not of a single one, leads to striking defects in cell shape and in cell growth, indicating important overlapping functions of flotillin paralogs. Our data show that FloA and FloT perform spatially distinct functions, possibly in the insertion of membrane proteins that require a specific lipid environment, based on a close connection between FloA and FloT with the Sec membrane insertion machinery, but do not act as scaffolds for detergent resistant proteins. Our tracking analyses provide an important basis for the understanding of interactions between membrane proteins in living cells.
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Affiliation(s)
- Felix Dempwolff
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Felix K. Schmidt
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Physics, Philipps Universität Marburg, Marburg, Germany
| | - Ana B. Hervás
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Alex Stroh
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Thomas C. Rösch
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Cornelius N. Riese
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Biology, Philipps Universität Marburg, Marburg, Germany
| | - Simon Dersch
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Thomas Heimerl
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Biology, Philipps Universität Marburg, Marburg, Germany
| | - Daniella Lucena
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Nikola Hülsbusch
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Norio Takeshita
- University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Ibaraki, Japan
- Department of Microbiology, Institute for Applied Bioscience, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Reinhard Fischer
- Department of Microbiology, Institute for Applied Bioscience, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Bruno Eckhardt
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Physics, Philipps Universität Marburg, Marburg, Germany
| | - Peter L. Graumann
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Marburg, Germany
- Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
- * E-mail:
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Somani VK, Aggarwal S, Singh D, Prasad T, Bhatnagar R. Identification of Novel Raft Marker Protein, FlotP in Bacillus anthracis. Front Microbiol 2016; 7:169. [PMID: 26925042 PMCID: PMC4756111 DOI: 10.3389/fmicb.2016.00169] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 02/01/2016] [Indexed: 01/14/2023] Open
Abstract
Lipid rafts are dynamic, nanoscale assemblies of specific proteins and lipids, distributed heterogeneously on eukaryotic membrane. Flotillin-1, a conserved eukaryotic raft marker protein (RMP) harbor SPFH (Stomatin, Prohibitin, Flotillin, and HflK/C) and oligomerization domains to regulate various cellular processes through its interactions with other signaling or transport proteins. Rafts were thought to be absent in prokaryotes hitherto, but recent report of its presence and significance in physiology of Bacillus subtilis prompted us to investigate the same in pathogenic bacteria (PB) also. In prokaryotes, proteins of SPFH2a subfamily show highest identity to SPFH domain of Flotillin-1. Moreover, bacterial genome organization revealed that Flotillin homolog harboring SPFH2a domain exists in an operon with an upstream gene containing NFeD domain. Here, presence of RMP in PB was initially investigated in silico by analyzing the presence of SPFH2a, oligomerization domains in the concerned gene and NfeD domain in the adjacent upstream gene. After investigating 300 PB, four were found to harbor RMP. Among them, domains of Bas0525 (FlotP) of Bacillus anthracis (BA) showed highest identity with characteristic domains of RMP. Considering the global threat of BA as the bioterror agent, it was selected as a model for further in vitro characterization of rafts in PB. In silico and in vitro analysis showed significant similarity of FlotP with numerous attributes of Flotillin-1. Its punctate distribution on membrane with exclusive localization in detergent resistant membrane fraction; strongly favors presence of raft with RMP FlotP in BA. Furthermore, significant effect of Zaragozic acid (ZA), a raft associated lipid biosynthesis inhibitor, on several patho-physiological attributes of BA such as growth, morphology, membrane rigidity etc., were also observed. Specifically, a considerable decrease in membrane rigidity, strongly recommended presence of an unknown raft associated lipid molecule on membrane of BA. In addition, treatment with ZA decreased secretion of anthrax toxins and FlotP expression, suggesting potential role of raft in pathogenesis and physiology of BA. Thus, the present study not only suggest the existence and role of raft like entity in pathophysiology of BA but also its possible use for the development of novel drugs or vaccines against anthrax.
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Affiliation(s)
- Vikas K Somani
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University New Delhi, India
| | - Somya Aggarwal
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University New Delhi, India
| | - Damini Singh
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University New Delhi, India
| | | | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University New Delhi, India
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49
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Li Q, Peng J, Li X, Leng A, Liu T. miR-449a targets Flot2 and inhibits gastric cancer invasion by inhibiting TGF-β-mediated EMT. Diagn Pathol 2015; 10:202. [PMID: 26576674 PMCID: PMC4650491 DOI: 10.1186/s13000-015-0435-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/17/2015] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Flot2, a highly conserved protein of the SPFH domain containing proteins family, has recently been identified as oncogene to be involved in the tumorigenesis and metastasis of several cancers including gastric cancer. However, the underlying molecular mechanism of Flot2 in gastric cancer (GC) is largely unknown. METHODS qRT-PCR and western blot was performed to detect miR-449a and Flot2 expression in GC cell lines and Normal human gastric epithelial cells. Then, luciferase reporter assay was used to elucidate whether Flot2 is a target gene of miR-449a. Finally, the roles and mechanism of miR-449a in regulation of tumor invasion were further investigated. RESULTS In this study, miR-449a expression was downregulated and Flot2 was upregulated in all GC cell lines as compared with that in GES-1. luciferase reporter assay identified Flot2 as a novel direct target of miR-449a. miR-449a regulated GC cell invasion by suppressing Flot2 expression. Expression analysis of a set of epithelial-mesenchymal transition (EMT) markers showed that miR-449a reduced the expression of mesenchymal markers (vimentin and N-cadherin) and induced the expression of epithelial marker (E-cadherin), which was consistent with silenced Flot2. Moreover, Flot2 is necessary for TGF-β-induced EMT in GC cells. CONCLUSIONS Our results demonstrated that miR-449a suppressed Flot2 expression results in decreased cell invasion through repressing TGF-β-mediated-EMT, and provides a new theoretical basis to further investigate miR-449a-regulated Flot2 as a potential biomarker and a promising approach for GC treatment.
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Affiliation(s)
- Qian Li
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P. R. China.
| | - Jie Peng
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P. R. China.
| | - Xinhua Li
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P. R. China.
| | - Aimin Leng
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P. R. China.
| | - Ting Liu
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P. R. China.
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Lopez D. Molecular composition of functional microdomains in bacterial membranes. Chem Phys Lipids 2015; 192:3-11. [PMID: 26320704 DOI: 10.1016/j.chemphyslip.2015.08.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 08/10/2015] [Accepted: 08/24/2015] [Indexed: 12/14/2022]
Abstract
Membranes of eukaryotic cells organize a number of proteins related to signal transduction and membrane trafficking into microdomains, which are enriched in particular lipids, like cholesterol and sphingolipids and are commonly referred as to lipid rafts or membrane rafts. The existence of this type of signaling platforms was traditionally associated with eukaryotic membranes because prokaryotic cells were considered too simple organisms to require a sophisticated organization of their signaling networks. However, the research that have been performed during last years have shown that bacteria organize many signaling transduction processes in Functional Membrane Microdomains (FMMs), which are similar to the lipid rafts that are found in eukaryotic cells. The current knowledge of the existence of FMMs in bacteria is described in this review and the specific structural and biological properties of these membrane microdomains are introduced. The organization of FMMs in bacterial membranes reveals an unexpected level of sophistication in signaling transduction and membrane organization that is unprecedented in bacteria, suggesting that bacteria as more complex organisms than previously considered.
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Affiliation(s)
- Daniel Lopez
- Research Center for Infectious Diseases (ZINF), Institute for Molecular Infection Biology (IMIB), University of Würzburg, Josef-Schneider Strasse (2), 97080 Würzburg, Germany; Spanish National Center for Biotechnology (CNB), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain.
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