1
|
Dicks EM, Tyrer JP, Ezquina S, Jones M, Baierl J, Peng PC, Diaz M, Goode E, Winham SJ, Dörk T, Van Gorp T, De Fazio A, Bowtell D, Odunsi K, Moysich K, Pavanello M, Campbell I, Brenton JD, Ramus SJ, Gayther SA, Pharoah PDP. Exome sequencing identifies HELB as a novel susceptibility gene for non-mucinous, non-high-grade-serous epithelial ovarian cancer. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.02.24304968. [PMID: 38633804 PMCID: PMC11023670 DOI: 10.1101/2024.04.02.24304968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Rare, germline loss-of-function variants in a handful of genes that encode DNA repair proteins have been shown to be associated with epithelial ovarian cancer with a stronger association for the high-grade serous hiostotype. The aim of this study was to collate exome sequencing data from multiple epithelial ovarian cancer case cohorts and controls in order to systematically evaluate the role of coding, loss-of-function variants across the genome in epithelial ovarian cancer risk. We assembled exome data for a total of 2,573 non-mucinous cases (1,876 high-grade serous and 697 non-high grade serous) and 13,925 controls. Harmonised variant calling and quality control filtering was applied across the different data sets. We carried out a gene-by-gene simple burden test for association of rare loss-of-function variants (minor allele frequency < 0.1%) with all non-mucinous ovarian cancer, high grade serous ovarian cancer and non-high grade serous ovarian cancer using logistic regression adjusted for the top four principal components to account for cryptic population structure and genetic ancestry. Seven of the top 10 associated genes were associations of the known ovarian cancer susceptibility genes BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, MSH6 and PALB2 (false discovery probability < 0.1). A further four genes (HELB, OR2T35, NBN and MYO1A) had a false discovery rate of less than 0.1. Of these, HELB was most strongly associated with the non-high grade serous histotype (P = 1.3×10-6, FDR = 9.1×10-4). Further support for this association comes from the observation that loss of function variants in this gene are also associated with age at natural menopause and Mendelian randomisation analysis shows an association between genetically predicted age at natural menopause and endometrioid ovarian cancer, but not high-grade serous ovarian cancer.
Collapse
Affiliation(s)
- Ed M Dicks
- Department of Public Health and Primary Care, University of Cambridge, UK
| | - Jonthan P Tyrer
- Department of Public Health and Primary Care, University of Cambridge, UK
| | - Suzana Ezquina
- Department of Public Health and Primary Care, University of Cambridge, UK
| | - Michelle Jones
- Department of Biomedical Sciences, Cedars-Sinai Medical Centre, Los Angeles, USA
| | - John Baierl
- Department of Computational Biomedicine, Cedars-Sinai Medical Centre, Los Angeles, USA
| | - Pei-Chen Peng
- Department of Computational Biomedicine, Cedars-Sinai Medical Centre, Los Angeles, USA
| | - Michael Diaz
- Department of Biomedical Sciences, Cedars-Sinai Medical Centre, Los Angeles, USA
| | | | | | - Thilo Dörk
- Gynaecology Research Unit, Hannover Medical School, Hannover, Germany
| | - Toon Van Gorp
- Department of Gynaecology and Obstetrics, University Hospitals Leuven, Leuven, Belgium
| | - Ana De Fazio
- Centre for Cancer Research, The Westmead Institute for Medical Research, The Daffodil Centre, The University of Sydney, a joint venture with Cancer Council NSW and Department of Gynaecological Oncology, Westmead Hospital, Sydney, New South Wales, Australia
| | - David Bowtell
- Cancer Genomics and Genetics and Women's Cancer Programs, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Kunle Odunsi
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, IL, USA
| | - Kirsten Moysich
- Division of Cancer Prevention and Control, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Marina Pavanello
- School of Clinical Medicine, Faculty of Medicine and Health, University of NSW, Sydney, NSW, Australia Center for Research in Immuno-Oncology, Albert Einstein Israelite Hospital, São Paulo, SP, Brazil
| | - Ian Campbell
- Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, Melbourne, Australia
| | | | - Susan J Ramus
- School of Clinical Medicine, Faculty of Medicine and Health, University of NSW, Sydney, NSW, Australia Adult Cancer Program, Lowy Cancer Research Centre, University of NSW, Sydney, NSW, Australia
| | - Simon A Gayther
- Department of Biomedical Sciences, Cedars-Sinai Medical Centre, Los Angeles, USA
| | - Paul D P Pharoah
- Department of Computational Biomedicine, Cedars-Sinai Medical Centre, Los Angeles, USA
| |
Collapse
|
2
|
Xie H, Weinstein H. Allosterically coupled conformational dynamics in solution prepare the sterol transfer protein StarD4 to release its cargo upon interaction with target membranes. Front Mol Biosci 2023; 10:1197154. [PMID: 37275961 PMCID: PMC10232897 DOI: 10.3389/fmolb.2023.1197154] [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: 03/30/2023] [Accepted: 05/04/2023] [Indexed: 06/07/2023] Open
Abstract
Complex mechanisms regulate the cellular distribution of cholesterol, a critical component of eukaryote membranes involved in regulation of membrane protein functions directly and through the physiochemical properties of membranes. StarD4, a member of the steroidogenic acute regulator-related lipid-transfer (StART) domain (StARD)-containing protein family, is a highly efficient sterol-specific transfer protein involved in cholesterol homeostasis. Its mechanism of cargo loading and release remains unknown despite recent insights into the key role of phosphatidylinositol phosphates in modulating its interactions with target membranes. We have used large-scale atomistic Molecular dynamics (MD) simulations to study how the dynamics of cholesterol bound to the StarD4 protein can affect interaction with target membranes, and cargo delivery. We identify the two major cholesterol (CHL) binding modes in the hydrophobic pocket of StarD4, one near S136&S147 (the Ser-mode), and another closer to the putative release gate located near W171, R92&Y117 (the Trp-mode). We show that conformational changes of StarD4 associated directly with the transition between these binding modes facilitate the opening of the gate. To understand the dynamics of this connection we apply a machine-learning algorithm for the detection of rare events in MD trajectories (RED), which reveals the structural motifs involved in the opening of a front gate and a back corridor in the StarD4 structure occurring together with the spontaneous transition of CHL from the Ser-mode of binding to the Trp-mode. Further analysis of MD trajectory data with the information-theory based NbIT method reveals the allosteric network connecting the CHL binding site to the functionally important structural components of the gate and corridor. Mutations of residues in the allosteric network are shown to affect the performance of the allosteric connection. These findings outline an allosteric mechanism which prepares the CHL-bound StarD4 to release and deliver the cargo when it is bound to the target membrane.
Collapse
Affiliation(s)
- Hengyi Xie
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, United States
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, United States
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, United States
| |
Collapse
|
3
|
Krishnamurthy S, Maru P, Wang Y, Bitew MA, Mukhopadhyay D, Yamaryo-Botté Y, Paredes-Santos TC, Sangaré LO, Swale C, Botté CY, Saeij JPJ. CRISPR Screens Identify Toxoplasma Genes That Determine Parasite Fitness in Interferon Gamma-Stimulated Human Cells. mBio 2023; 14:e0006023. [PMID: 36916910 PMCID: PMC10128063 DOI: 10.1128/mbio.00060-23] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 01/11/2023] [Indexed: 03/16/2023] Open
Abstract
Toxoplasma virulence depends on its ability to evade or survive the toxoplasmacidal mechanisms induced by interferon gamma (IFNγ). While many Toxoplasma genes involved in the evasion of the murine IFNγ response have been identified, genes required to survive the human IFNγ response are largely unknown. In this study, we used a genome-wide loss-of-function screen to identify Toxoplasma genes important for parasite fitness in IFNγ-stimulated primary human fibroblasts. We generated gene knockouts for the top six hits from the screen and confirmed their importance for parasite growth in IFNγ-stimulated human fibroblasts. Of these six genes, three have homology to GRA32, localize to dense granules, and coimmunoprecipitate with each other and GRA32, suggesting they might form a complex. Deletion of individual members of this complex leads to early parasite egress in IFNγ-stimulated cells. Thus, prevention of early egress is an important Toxoplasma fitness determinant in IFNγ-stimulated human cells. IMPORTANCE Toxoplasma infection causes serious complications in immunocompromised individuals and in the developing fetus. During infection, certain immune cells release a protein called interferon gamma that activates cells to destroy the parasite or inhibit its growth. While most Toxoplasma parasites are cleared by this immune response, some can survive by blocking or evading the IFNγ-induced restrictive environment. Many Toxoplasma genes that determine parasite survival in IFNγ-activated murine cells are known but parasite genes conferring fitness in IFNγ-activated human cells are largely unknown. Using a Toxoplasma adapted genome-wide loss-of-function screen, we identified many Toxoplasma genes that determine parasite fitness in IFNγ-activated human cells. The gene products of four top hits play a role in preventing early parasite egress in IFNγ-stimulated human cells. Understanding how IFNγ-stimulated human cells inhibit Toxoplasma growth and how Toxoplasma counteracts this, could lead to the development of novel therapeutics.
Collapse
Affiliation(s)
- Shruthi Krishnamurthy
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Yifan Wang
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Debanjan Mukhopadhyay
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Yoshiki Yamaryo-Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Batiment Jean Roget, Grenoble, France
| | - Tatiana C. Paredes-Santos
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Lamba O. Sangaré
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Cyrille Y. Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Batiment Jean Roget, Grenoble, France
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| |
Collapse
|
4
|
Yue X, Kong Y, Zhang Y, Sun M, Liu S, Wu Z, Gao L, Liang X, Ma C. SREBF2-STARD4 axis confers sorafenib resistance in hepatocellular carcinoma by regulating mitochondrial cholesterol homeostasis. Cancer Sci 2022; 114:477-489. [PMID: 35642354 PMCID: PMC9899602 DOI: 10.1111/cas.15449] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/21/2022] [Accepted: 05/26/2022] [Indexed: 01/07/2023] Open
Abstract
Sorafenib resistance limits its survival benefit for treatment of hepatocellular carcinoma (HCC). Cholesterol metabolism is dysregulated in HCC, and its role in sorafenib resistance of HCC has not been fully elucidated. Aiming to elucidate this, in vitro and in vivo sorafenib resistant models were established. Sterol regulatory element binding transcription factor 2 (SREBF2), the key regulator of cholesterol metabolism, was activated in sorafenib resistant HepG2 and Huh7 cells. Knockdown of SREBF2 resensitized sorafenib resistant cells and xenografts tumors to sorafenib. Further study showed that SREBF2 positively correlated with StAR related lipid transfer domain containing 4 (STARD4) in our sorafenib resistant models and publicly available datasets. STARD4, mediating cholesterol trafficking, not only promoted proliferation and migration of HepG2 and Huh7 cells, but also increased sorafenib resistance in liver cancer. Mechanically, SREBF2 promoted expression of STARD4 by directly binding to its promoter region, leading to increased mitochondrial cholesterol levels and inhibition of mitochondrial cytochrome c release. Importantly, knockdown of SREBF2 or STARD4 decreased mitochondrial cholesterol levels and increased mitochondrial cytochrome c release, respectively. Moreover, overexpression of STARD4 reversed the effect of SREBF2 knockdown on mitochondrial cytochrome c release and sorafenib resistance. In conclusion, SREBF2 promotes STARD4 transcription, which in turn contributes to mitochondrial cholesterol transport and sorafenib resistance in HCC. Therefore, targeting the SREBF2-STARD4 axis would be beneficial to a subset of HCC patients with sorafenib resistance.
Collapse
Affiliation(s)
- Xuetian Yue
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Youzi Kong
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Yankun Zhang
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Min Sun
- Department of Hernia and Abdominal Wall Surgery, General Surgery, Qilu Hospital, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Shuyue Liu
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Zhuanchang Wu
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Lifen Gao
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Xiaohong Liang
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Chunhong Ma
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| |
Collapse
|
5
|
Mukherjee T, Subedi B, Khosla A, Begler EM, Stephens PM, Warner AL, Lerma-Reyes R, Thompson KA, Gunewardena S, Schrick K. The START domain mediates Arabidopsis GLABRA2 dimerization and turnover independently of homeodomain DNA binding. PLANT PHYSIOLOGY 2022; 190:2315-2334. [PMID: 35984304 PMCID: PMC9706451 DOI: 10.1093/plphys/kiac383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/09/2022] [Indexed: 05/08/2023]
Abstract
Class IV homeodomain leucine-zipper transcription factors (HD-Zip IV TFs) are key regulators of epidermal differentiation that are characterized by a DNA-binding HD in conjunction with a lipid-binding domain termed steroidogenic acute regulatory-related lipid transfer (START). Previous work established that the START domain of GLABRA2 (GL2), a HD-Zip IV member from Arabidopsis (Arabidopsis thaliana), is required for TF activity. Here, we addressed the functions and possible interactions of START and the HD in DNA binding, dimerization, and protein turnover. Deletion analysis of the HD and missense mutations of a conserved lysine (K146) resulted in phenotypic defects in leaf trichomes, root hairs, and seed mucilage, similar to those observed for START domain mutants, despite nuclear localization of the respective proteins. In vitro and in vivo experiments demonstrated that while HD mutations impair binding to target DNA, the START domain is dispensable for DNA binding. Vice versa, protein interaction assays revealed impaired GL2 dimerization for multiple alleles of START mutants, but not HD mutants. Using in vivo cycloheximide chase experiments, we provided evidence for the role of START, but not HD, in maintaining protein stability. This work advances our mechanistic understanding of HD-Zip TFs as multidomain regulators of epidermal development in plants.
Collapse
Affiliation(s)
- Thiya Mukherjee
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Molecular, Cellular and Developmental Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Donald Danforth Plant Science Center, Olivette, Missouri 63132, USA
| | - Bibek Subedi
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Molecular, Cellular and Developmental Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Aashima Khosla
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Molecular, Cellular and Developmental Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Erika M Begler
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Preston M Stephens
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Adara L Warner
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Ruben Lerma-Reyes
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Interdepartmental Genetics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Kyle A Thompson
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - Sumedha Gunewardena
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - Kathrin Schrick
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
- Molecular, Cellular and Developmental Biology, Kansas State University, Manhattan, Kansas 66506, USA
| |
Collapse
|
6
|
Wei X, Yin F, Wu M, Xie Q, Zhao X, Zhu C, Xie R, Chen C, Liu M, Wang X, Ren R, Kang G, Zhu C, Cong J, Wang H, Wang X. G protein-coupled receptor 35 attenuates nonalcoholic steatohepatitis by reprogramming cholesterol homeostasis in hepatocytes. Acta Pharm Sin B 2022; 13:1128-1144. [PMID: 36970193 PMCID: PMC10031266 DOI: 10.1016/j.apsb.2022.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/08/2022] [Accepted: 08/18/2022] [Indexed: 11/15/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Fat accumulation "sensitizes" the liver to insult and leads to nonalcoholic steatohepatitis (NASH). G protein-coupled receptor 35 (GPR35) is involved in metabolic stresses, but its role in NAFLD is unknown. We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis. Specifically, we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose (HFCF) diet-induced steatohepatitis, whereas loss of GPR35 had the opposite effect. Administration of the GPR35 agonist kynurenic acid (Kyna) suppressed HFCF diet-induced steatohepatitis in mice. Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4 (STARD4) through the ERK1/2 signaling pathway, ultimately resulting in hepatic cholesterol esterification and bile acid synthesis (BAS). The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and CYP8B1, promoting the conversion of cholesterol to bile acid. The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice. STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice. Our findings indicate that the GPR35-STARD4 axis is a promising therapeutic target for NAFLD.
Collapse
Affiliation(s)
- Xiaoli Wei
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
| | - Fan Yin
- Department of Pharmacy, Huainan First People's Hospital, the First Affiliated Hospital of Anhui University of Science and Technology, Huainan 232001, China
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
| | - Miaomiao Wu
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
| | - Qianqian Xie
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Xueqin Zhao
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Cheng Zhu
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
| | - Ruiqian Xie
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Chongqing Chen
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Menghua Liu
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Xueying Wang
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
| | - Ruixue Ren
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
| | - Guijie Kang
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Chenwen Zhu
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
| | - Jingjing Cong
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
| | - Hua Wang
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei 230036, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
- Corresponding authors.
| | - Xuefu Wang
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei 230032, China
- Corresponding authors.
| |
Collapse
|
7
|
Depta L, Whitmarsh-Everiss T, Laraia L. Structure, function and small molecule modulation of intracellular sterol transport proteins. Bioorg Med Chem 2022; 68:116856. [PMID: 35716590 DOI: 10.1016/j.bmc.2022.116856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/23/2022] [Indexed: 11/02/2022]
Abstract
Intracellular sterol transport proteins (STPs) are crucial for maintaining cellular lipid homeostasis by regulating local sterol pools. Despite structural similarities in their sterol binding domains, STPs have different substrate specificities, intracellular localisation and biological functions. In this review, we highlight recent advances in the determination of STP structures and how this regulates their lipid specificities. Furthermore, we cover the important discoveries relating to the intracellular localisation of STPs, and the organelles between which lipid transport is carried out, giving rise to specific functions in health and disease. Finally, serendipitous and targeted efforts to identify small molecule modulators of STPs, as well as their ability to act as tool compounds and potential therapeutics, will be discussed.
Collapse
Affiliation(s)
- Laura Depta
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Thomas Whitmarsh-Everiss
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Luca Laraia
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark.
| |
Collapse
|
8
|
Phosphatidylinositol phosphates modulate interactions between the StarD4 sterol trafficking protein and lipid membranes. J Biol Chem 2022; 298:102058. [PMID: 35605664 PMCID: PMC9207681 DOI: 10.1016/j.jbc.2022.102058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/12/2022] [Accepted: 05/18/2022] [Indexed: 11/22/2022] Open
Abstract
There is substantial evidence for extensive nonvesicular sterol transport in cells. For example, lipid transfer by the steroidogenic acute regulator-related proteins (StarD) containing a StarT domain has been shown to involve several pathways of nonvesicular trafficking. Among the soluble StarT domain–containing proteins, StarD4 is expressed in most tissues and has been shown to be an effective sterol transfer protein. However, it was unclear whether the lipid composition of donor or acceptor membranes played a role in modulating StarD4-mediated transport. Here, we used fluorescence-based assays to demonstrate a phosphatidylinositol phosphate (PIP)-selective mechanism by which StarD4 can preferentially extract sterol from liposome membranes containing certain PIPs (especially, PI(4,5)P2 and to a lesser degree PI(3,5)P2). Monophosphorylated PIPs and other anionic lipids had a smaller effect on sterol transport. This enhancement of transport was less effective when the same PIPs were present in the acceptor membranes. Furthermore, using molecular dynamics (MD) simulations, we mapped the key interaction sites of StarD4 with PIP-containing membranes and identified residues that are important for this interaction and for accelerated sterol transport activity. We show that StarD4 recognizes membrane-specific PIPs through specific interaction with the geometry of the PIP headgroup as well as the surrounding membrane environment. Finally, we also observed that StarD4 can deform membranes upon longer incubations. Taken together, these results suggest a mechanism by which PIPs modulate cholesterol transfer activity via StarD4.
Collapse
|
9
|
Adipogenesis of ear mesenchymal stem cells (EMSCs): adipose biomarker-based assessment of genetic variation, adipocyte function, and brown/brite differentiation. Mol Cell Biochem 2022; 477:1053-1063. [PMID: 34997885 DOI: 10.1007/s11010-021-04350-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 12/23/2021] [Indexed: 10/19/2022]
Abstract
Ear mesenchymal stem cells (EMSCs) have been investigated to differentiate into adipocytes, chondrocytes, and muscle cells in vitro. However, the factors controlling adipogenesis of this stem cell population in vitro, function, and type of adipocytes raised from them are still unclear. Here we found that genetics have a modest effect on adipogenic capacity of EMSCs. Adipocytes differentiated from EMSCs have a potential function in lipid metabolism as indicated by expression of lipogenic genes and this function of EMSC adipocytes is regulated by genetics. EMSCs failed to be differentiated into brite/brown adipocytes due to their lack of a thermogenic program, but adipocytes raised from EMSCs showed a fate of white adipocytes. Overall, our data suggest that EMSCs differentiate into functional white adipocytes in vitro and this is genetic-dependent.
Collapse
|
10
|
Asif K, Memeo L, Palazzolo S, Frión-Herrera Y, Parisi S, Caligiuri I, Canzonieri V, Granchi C, Tuccinardi T, Rizzolio F. STARD3: A Prospective Target for Cancer Therapy. Cancers (Basel) 2021; 13:4693. [PMID: 34572920 PMCID: PMC8472075 DOI: 10.3390/cancers13184693] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/10/2021] [Indexed: 12/24/2022] Open
Abstract
Cancer is one of the major causes of death in developed countries and current therapies are based on surgery, chemotherapeutic agents, and radiation. To overcome side effects induced by chemo- and radiotherapy, in recent decades, targeted therapies have been proposed in second and even first lines. Targeted drugs act on the essential pathways involved in tumor induction, progression, and metastasis, basically all the hallmark of cancers. Among emerging pathways, the cholesterol metabolic pathway is a strong candidate for this purpose. Cancer cells have an accelerated metabolic rate and require a continuous supply of cholesterol for cell division and membrane renewal. Steroidogenic acute regulatory related lipid transfer (START) proteins are a family of proteins involved in the transfer of lipids and some of them are important in non-vesicular cholesterol transportation within the cell. The alteration of their expression levels is implicated in several diseases, including cancers. In this review, we report the latest discoveries on StAR-related lipid transfer protein domain 3 (STARD3), a member of the START family, which has a potential role in cancer, focusing on the structural and biochemical characteristics and mechanisms that regulate its activity. The role of the STARD3 protein as a molecular target for the development of cancer therapies is also discussed. As STARD3 is a key protein in the cholesterol movement in cancer cells, it is of interest to identify inhibitors able to block its activity.
Collapse
Affiliation(s)
- Kanwal Asif
- Department of Molecular Sciences and Nanosystems, PhD School in Science and Technology of Bio and Nanomaterials, Ca’ Foscari University of Venice, 30172 Venice, Italy;
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
| | - Lorenzo Memeo
- Department of Experimental Oncology, Mediterranean Institute of Oncology, 95029 Catania, Italy;
| | - Stefano Palazzolo
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
| | - Yahima Frión-Herrera
- Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, 30172 Venice, Italy; or
| | - Salvatore Parisi
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
| | - Isabella Caligiuri
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
| | - Vincenzo Canzonieri
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy
| | - Carlotta Granchi
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (C.G.); (T.T.)
| | - Tiziano Tuccinardi
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy; (C.G.); (T.T.)
| | - Flavio Rizzolio
- Pathology Unit, Centro di Riferimento Oncologico di Aviano (C.R.O.) IRCCS, 33081 Aviano, Italy; (S.P.); (S.P.); (V.C.)
- Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, 30172 Venice, Italy; or
| |
Collapse
|
11
|
The Expanding Role of Mitochondria, Autophagy and Lipophagy in Steroidogenesis. Cells 2021; 10:cells10081851. [PMID: 34440620 PMCID: PMC8391558 DOI: 10.3390/cells10081851] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
The fundamental framework of steroidogenesis is similar across steroidogenic cells, especially in initial mitochondrial steps. For instance, the START domain containing protein-mediated cholesterol transport to the mitochondria, and its conversion to pregnenolone by the enzyme P450scc, is conserved across steroidogenic cells. The enzyme P450scc localizes to the inner mitochondrial membrane, which makes the mitochondria essential for steroidogenesis. Despite this commonality, mitochondrial structure, number, and dynamics vary substantially between different steroidogenic cell types, indicating implications beyond pregnenolone biosynthesis. This review aims to focus on the growing roles of mitochondria, autophagy and lipophagy in cholesterol uptake, trafficking and homeostasis in steroidogenic cells and consequently in steroidogenesis. We will focus on these aspects in the context of the physiological need for different steroid hormones and cell-intrinsic inherent features in different steroidogenic cell types beyond mitochondria as a mere site for the beginning of steroidogenesis. The overall goal is to provide an authentic and comprehensive review on the expanding role of steroidogenic cell-intrinsic processes in cholesterol homeostasis and steroidogenesis, and to bring attention to the scientific community working in this field on these promising advancements. Moreover, we will discuss a novel mitochondrial player, prohibitin, and its potential role in steroidogenic mitochondria and cells, and consequently, in steroidogenesis.
Collapse
|
12
|
Vetrici MA, Yevtushenko DP, Misra S. Douglas-fir LEAFY COTYLEDON1 ( PmLEC1) is an active transcription factor during zygotic and somatic embryogenesis. PLANT DIRECT 2021; 5:e00333. [PMID: 34355111 PMCID: PMC8320655 DOI: 10.1002/pld3.333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
Douglas-fir (Pseudotsuga menziesii) is one of the world's premier lumber species and somatic embryogenesis (SE) is the most promising method for rapid propagation of superior tree genotypes. The development and optimization of SE protocols in conifers is hindered by a lack of knowledge of the molecular basis of embryogenesis and limited sequence data. In Arabidopsis, the LEAFY COTYLEDON1 (AtLEC1) gene is a master regulator of embryogenesis that induces SE when expressed ectopically. We isolated the LEC1 homologue from Douglas-fir, designated as PmLEC1. PmLEC1 expression in somatic embryos and developing seeds demonstrated a unique, alternating pattern of expression with the highest levels during early stages of embryogenesis. PmLEC1 protein accumulation during seed development correlated with its transcriptional levels during early embryogenesis; however, substantial protein levels persisted until 2 weeks on germination medium. Treatment of mature, stratified seeds with 2,4-epibrassinolide, sorbitol, mannitol, or NaCl upregulated PmLEC1 expression, which may provide strategies to induce SE from mature tissues. Sequence analysis of the PmLEC1 gene revealed a 5' UTR intron containing binding sites for transcription factors (TFs), such as ABI3, LEC2, FUS3, and AGL15, which are critical regulators of embryogenesis in angiosperms. Regulatory elements for these and other seed-specific TFs and biotic and abiotic signals were identified within the PmLEC1 locus. Most importantly, functional analysis of PmLEC1 showed that it rescued the Arabidopsis lec1-1 null mutant and, in the T2 generation, led to the development of embryo-like structures, indicating a key role of PmLEC1 in the regulation of embryogenesis.
Collapse
Affiliation(s)
- Mariana A. Vetrici
- Department of Biological SciencesUniversity of LethbridgeLethbridgeABCanada
- Centre for Forest BiologyDepartment of Biochemistry & MicrobiologyUniversity of VictoriaVictoriaBCCanada
| | | | - Santosh Misra
- Centre for Forest BiologyDepartment of Biochemistry & MicrobiologyUniversity of VictoriaVictoriaBCCanada
| |
Collapse
|
13
|
Müller SJ, Schurz H, Tromp G, van der Spuy GD, Hoal EG, van Helden PD, Owusu-Dabo E, Meyer CG, Muntau B, Thye T, Niemann S, Warren RM, Streicher E, Möller M, Kinnear C. A multi-phenotype genome-wide association study of clades causing tuberculosis in a Ghanaian- and South African cohort. Genomics 2021; 113:1802-1815. [PMID: 33862184 DOI: 10.1016/j.ygeno.2021.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 03/26/2021] [Accepted: 04/11/2021] [Indexed: 01/31/2023]
Abstract
Despite decades of research and advancements in diagnostics and treatment, tuberculosis remains a major public health concern. New computational methods are needed to interrogate the intersection of host- and bacterial genomes. Paired host genotype datum and infecting bacterial isolate information were analysed for associations using a multinomial logistic regression framework implemented in SNPTest. A cohort of 853 admixed South African participants and a Ghanaian cohort of 1359 participants were included. Two directly genotyped variants, namely rs529920 and rs41472447, were identified in the Ghanaian cohort as being statistically significantly associated with risk for infection with strains of different members of the MTBC. Thus, a multinomial logistic regression using paired host-pathogen data may prove valuable for investigating the complex relationships driving infectious disease.
Collapse
Affiliation(s)
- Stephanie J Müller
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa; South African Tuberculosis Bioinformatics Initiative (SATBBI), Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
| | - Haiko Schurz
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa; South African Tuberculosis Bioinformatics Initiative (SATBBI), Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Gerard Tromp
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa; South African Tuberculosis Bioinformatics Initiative (SATBBI), Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Gian D van der Spuy
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa; South African Tuberculosis Bioinformatics Initiative (SATBBI), Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Eileen G Hoal
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Paul D van Helden
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Ellis Owusu-Dabo
- School of Public Health, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Christian G Meyer
- Institute of Tropical Medicine, Eberhard-Karls University, Tübingen, Germany; Faculty of Medicine, Duy Tan University, Da Nang, Vietnam
| | - Birgit Muntau
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Thorsten Thye
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefan Niemann
- German Centre for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel, Borstel, Germany
| | - Robin M Warren
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Elizabeth Streicher
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Marlo Möller
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Craig Kinnear
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| |
Collapse
|
14
|
Miyamoto S, Lima RS, Inague A, Viviani LG. Electrophilic oxysterols: generation, measurement and protein modification. Free Radic Res 2021; 55:416-440. [PMID: 33494620 DOI: 10.1080/10715762.2021.1879387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholesterol is an essential component of mammalian plasma membranes. Alterations in sterol metabolism or oxidation have been linked to various pathological conditions, including cardiovascular diseases, cancer, and neurodegenerative disorders. Unsaturated sterols are vulnerable to oxidation induced by singlet oxygen and other reactive oxygen species. This process yields reactive sterol oxidation products, including hydroperoxides, epoxides as well as aldehydes. These oxysterols, in particular those with high electrophilicity, can modify nucleophilic sites in biomolecules and affect many cellular functions. Here, we review the generation and measurement of reactive sterol oxidation products with emphasis on cholesterol hydroperoxides and aldehyde derivatives (electrophilic oxysterols) and their effects on protein modifications.
Collapse
Affiliation(s)
- Sayuri Miyamoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Rodrigo S Lima
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Alex Inague
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Lucas G Viviani
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| |
Collapse
|
15
|
Zhang M, Xiang Z, Wang F, Shan R, Li L, Chen J, Liu BA, Huang J, Sun LQ, Zhou WB. STARD4 promotes breast cancer cell malignancy. Oncol Rep 2020; 44:2487-2502. [PMID: 33125124 PMCID: PMC7610339 DOI: 10.3892/or.2020.7802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 08/24/2020] [Indexed: 12/24/2022] Open
Abstract
Breast cancer (BRCA) is one of the most common malignancies encountered in women worldwide. Lipid metabolism has been found to be involved in cancer progression. Steroidogenic acute regulatory protein-related lipid transfer 4 (STARD4) is an important cholesterol transporter involved in the regulatory mechanism of intracellular cholesterol homeostasis. However, to the best of our knowledge, the molecular functions of STARD4 in BRCA are unclear. Immunohistochemical staining and public dataset analysis were performed to investigate the expression levels of STARD4 in BRCA. In the present study, high expression of STARD4 was identified in BRCA samples and higher STARD4 expression was significantly associated with shorter distant metastasis-free survival time in patients with BRCA, which indicated that STARD4 may be associated with BRCA progression. Cell cytometry system Celigo® analysis, Cell Counting K-8 assays, flow cytometry, wound healing assays and transwell assays were used to investigate the effects of STARD4 knockdown on proliferation, cell cycle, apoptosis and migration in BRCA cells. Loss-of-function assays demonstrated that STARD4 acted as an oncogene to promote proliferation and cell cycle progression, while suppressing apoptosis in BRCA cells in vitro and in vivo. Furthermore, knockdown of STARD4 significantly suppressed BRCA metastasis. To assess the mechanism of action of STARD4, microarray analysis was performed following STARD4 knockdown in MDA-MB-231 cells. The data were analyzed in detail using bioinformatics, and a series of genes, including E74 like ETS transcription factor 1, cAMP responsive element binding protein 1 and p21 (RAC1) activated kinase 2, which have been previously reported to be crucial genes implicated in the malignant phenotype of cancer cells, were identified to be regulated by STARD4. Loss-of function assays demonstrated that knockdown of STARD4 suppressed BRCA proliferation and migration. These findings suggested that STARD4 had an oncogenic effect in human BRCA progression.
Collapse
Affiliation(s)
- Min Zhang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Zhen Xiang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Feng Wang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Rong Shan
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Ling Li
- Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Juan Chen
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Bao-An Liu
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Juan Huang
- Hunan Province Clinic Meditech Research Center for Breast Cancer, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Lun-Quan Sun
- Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Wei-Bing Zhou
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| |
Collapse
|
16
|
Mandal SC, Tripathy PS, Khatei A, Behera DU, Ghosh A, Pandey PK, Parhi J. Genetics of colour variation in wild versus cultured queen loach, Botia dario (Hamilton, 1822). Genomics 2020; 112:3256-3267. [DOI: 10.1016/j.ygeno.2020.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/28/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
|
17
|
Katharopoulos E, Di Iorgi N, Fernandez-Alvarez P, Pandey AV, Groessl M, Dubey S, Camats N, Napoli F, Patti G, Lezzi M, Maghnie M, Flück CE. Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia. Int J Mol Sci 2020; 21:E6185. [PMID: 32867102 PMCID: PMC7504070 DOI: 10.3390/ijms21176185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 11/23/2022] Open
Abstract
Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH.
Collapse
Affiliation(s)
- Efstathios Katharopoulos
- Department of Paediatrics, Division of Endocrinology, Diabetology & Metabolism, Bern University Hospital, 3010 Bern, Switzerland; (E.K.); (A.V.P.); (S.D.)
- Department of Biomedical Research, Bern University Hospital and University of Bern, 3010 Bern, Switzerland;
- Graduate School Bern, University of Bern, 3012 Bern, Switzerland
| | - Natascia Di Iorgi
- Department of Paediatrics, Istituto Giannina Gaslini, University of Genoa, 16147 Genoa, Italy; (N.D.I.); (F.N.); (G.P.); (M.L.); (M.M.)
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16147 Genoa, Italy
| | - Paula Fernandez-Alvarez
- Department of Clinical and Molecular Genetics and Rare Disease Unit, University Hospital Vall d’Hebron, 08035 Barcelona, Spain;
| | - Amit V. Pandey
- Department of Paediatrics, Division of Endocrinology, Diabetology & Metabolism, Bern University Hospital, 3010 Bern, Switzerland; (E.K.); (A.V.P.); (S.D.)
- Department of Biomedical Research, Bern University Hospital and University of Bern, 3010 Bern, Switzerland;
| | - Michael Groessl
- Department of Biomedical Research, Bern University Hospital and University of Bern, 3010 Bern, Switzerland;
- Department of Nephrology and Hypertension, Bern University Hospital, 3010 Bern, Switzerland
| | - Shraddha Dubey
- Department of Paediatrics, Division of Endocrinology, Diabetology & Metabolism, Bern University Hospital, 3010 Bern, Switzerland; (E.K.); (A.V.P.); (S.D.)
- Department of Biomedical Research, Bern University Hospital and University of Bern, 3010 Bern, Switzerland;
| | - Núria Camats
- Growth and Development Research Unit, Vall d’Hebron Research Institute (VHIR), Centre of Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 08035 Barcelona, Spain;
| | - Flavia Napoli
- Department of Paediatrics, Istituto Giannina Gaslini, University of Genoa, 16147 Genoa, Italy; (N.D.I.); (F.N.); (G.P.); (M.L.); (M.M.)
| | - Giuseppa Patti
- Department of Paediatrics, Istituto Giannina Gaslini, University of Genoa, 16147 Genoa, Italy; (N.D.I.); (F.N.); (G.P.); (M.L.); (M.M.)
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16147 Genoa, Italy
| | - Marilea Lezzi
- Department of Paediatrics, Istituto Giannina Gaslini, University of Genoa, 16147 Genoa, Italy; (N.D.I.); (F.N.); (G.P.); (M.L.); (M.M.)
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16147 Genoa, Italy
| | - Mohamad Maghnie
- Department of Paediatrics, Istituto Giannina Gaslini, University of Genoa, 16147 Genoa, Italy; (N.D.I.); (F.N.); (G.P.); (M.L.); (M.M.)
| | - Christa E. Flück
- Department of Paediatrics, Division of Endocrinology, Diabetology & Metabolism, Bern University Hospital, 3010 Bern, Switzerland; (E.K.); (A.V.P.); (S.D.)
- Department of Biomedical Research, Bern University Hospital and University of Bern, 3010 Bern, Switzerland;
| |
Collapse
|
18
|
Clark BJ. The START-domain proteins in intracellular lipid transport and beyond. Mol Cell Endocrinol 2020; 504:110704. [PMID: 31927098 DOI: 10.1016/j.mce.2020.110704] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 12/17/2022]
Abstract
The Steroidogenic Acute Regulatory Protein-related Lipid Transfer (START) domain is a ~210 amino acid sequence that folds into an α/β helix-grip structure forming a hydrophobic pocket for lipid binding. The helix-grip fold structure defines a large superfamily of proteins, and this review focuses on the mammalian START domain family members that include single START domain proteins with identified ligands, and larger multi-domain proteins that may have novel roles in metabolism. Much of our understanding of the mammalian START domain proteins in lipid transport and changes in metabolism has advanced through studies using knockout mouse models, although for some of these proteins the identity and/or physiological role of ligand binding remains unknown. The findings that helped define START domain lipid-binding specificity, lipid transport, and changes in metabolism are presented to highlight that fundamental questions remain regarding the biological function(s) for START domain-containing proteins.
Collapse
Affiliation(s)
- Barbara J Clark
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
| |
Collapse
|
19
|
Chen S, Wang Y, Zhang L, Hu Y, Gu C, Wen Y, Gu A, Zhang J, Wang Y. SREBP2-STARD4 is involved in synthesis of cholesteryl ester stimulated by mono-butyl phthalate in MLTC-1 cells. ENVIRONMENTAL TOXICOLOGY 2020; 35:377-384. [PMID: 31705742 DOI: 10.1002/tox.22874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/24/2019] [Accepted: 10/26/2019] [Indexed: 06/10/2023]
Abstract
Sterol is synthesized from cholesterol which is from the hydrolysis of stored cholesteryl esters. The process of maintaining cholesterol homeostasis is regulated by SREBP2-STARD4. Lots of researches demonstrated that male steroidogenesis could be interfered by di-n-butyl phthalate (DBP) or monobutyl phthalate (MBP). However, mechanisms of MBP exposure in this process have not been uncovered clearly. The objectiveof this study was to explore roles of SREBP2 and STARD4 in cholesteryl estersynthesis stimulated by MBP in mouse Leydig tumor cells (MLTC-1). MLTC-1 exposedto 10-8, 10-7, 10-6, 10-5 M MBP showed that levels of cholestery ester were increased significantly at 10-7 M MBP. Besides, cholesteryl ester synthesis stimulated by MBP was down-regulate when STARD4 or SREBP2 were inhibited. Activity of SREBP2 binding to the promoter of STARD4 was increased after MBP exposure. This study suggests that MBP can increase cholesteryl ester synthesis through SREBP2-STARD4 signal pathway in MLTC-1 cells.
Collapse
Affiliation(s)
- Shanshan Chen
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
| | - Yidi Wang
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
| | - Lulu Zhang
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
- Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, Nanjing Medical University, Nanjing, China
| | - Yanhui Hu
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
- Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, Nanjing Medical University, Nanjing, China
| | - Chenxi Gu
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
| | - Yun Wen
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
| | - Aihua Gu
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
| | - Jingshu Zhang
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
- Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, Nanjing Medical University, Nanjing, China
| | - Yubang Wang
- The Key Laboratory of Modern Toxicology, Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- The Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China
- Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, Nanjing Medical University, Nanjing, China
| |
Collapse
|
20
|
Iaea DB, Spahr ZR, Singh RK, Chan RB, Zhou B, Bareja R, Elemento O, Di Paolo G, Zhang X, Maxfield FR. Stable reduction of STARD4 alters cholesterol regulation and lipid homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158609. [PMID: 31917335 DOI: 10.1016/j.bbalip.2020.158609] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/18/2019] [Accepted: 12/31/2019] [Indexed: 12/20/2022]
Abstract
STARD4, a member of the evolutionarily conserved START gene family, is a soluble sterol transport protein implicated in cholesterol sensing and maintenance of cellular homeostasis. STARD4 is widely expressed and has been shown to transfer sterol between liposomes as well as organelles in cells. However, STARD4 knockout mice lack an obvious phenotype, so the overall role of STARD4 is unclear. To model long term depletion of STARD4 in cells, we use short hairpin RNA technology to stably decrease STARD4 expression in human U2OS osteosarcoma cells (STARD4-KD). We show that STARD4-KD cells display increased total cholesterol, slower cholesterol trafficking between the plasma membrane and the endocytic recycling compartment, and increased plasma membrane fluidity. These effects can all be rescued by transient expression of a short hairpin RNA-resistant STARD4 construct. Some of the cholesterol increase was due to excess storage in late endosomes or lysosomes. To understand the effects of reduced STARD4, we carried out transcriptional and lipidomic profiling of control and STARD4-KD cells. Reduction of STARD4 activates compensatory mechanisms that alter membrane composition and lipid homeostasis. Based on these observations, we propose that STARD4 functions as a critical sterol transport protein involved in sterol sensing and maintaining lipid homeostasis.
Collapse
Affiliation(s)
- David B Iaea
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA; Weill Cornell Medical College, Rockefeller University, Memorial Sloan-Kettering Cancer Center Tri-Institutional Chemical Biology Program, New York, NY 10065, USA
| | - Zachary R Spahr
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA
| | - Rajesh K Singh
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA
| | - Robin B Chan
- Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
| | - Bowen Zhou
- Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
| | - Rohan Bareja
- Institute for Computational Biomedicine, Department of Physiology and Biophysics, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA
| | - Olivier Elemento
- Institute for Computational Biomedicine, Department of Physiology and Biophysics, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA
| | - Gilbert Di Paolo
- Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
| | - Xiaoxue Zhang
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA; Weill Cornell Medical College, Rockefeller University, Memorial Sloan-Kettering Cancer Center Tri-Institutional Chemical Biology Program, New York, NY 10065, USA.
| |
Collapse
|
21
|
Abstract
Synthesis and regulation of lipid levels and identities is critical for a wide variety of cellular functions, including structural and morphological properties of organelles, energy storage, signaling, and stability and function of membrane proteins. Proteolytic cleavage events regulate and/or influence some of these lipid metabolic processes and as a result help modulate their pleiotropic cellular functions. Proteins involved in lipid regulation are proteolytically cleaved for the purpose of their relocalization, processing, turnover, and quality control, among others. The scope of this review includes proteolytic events governing cellular lipid dynamics. After an initial discussion of the classic example of sterol regulatory element-binding proteins, our focus will shift to the mitochondrion, where a range of proteolytic events are critical for normal mitochondrial phospholipid metabolism and enforcing quality control therein. Recently, mitochondrial phospholipid metabolic pathways have been implicated as important for the proliferative capacity of cancers. Thus, the assorted proteases that regulate, monitor, or influence the activity of proteins that are important for phospholipid metabolism represent attractive targets to be manipulated for research purposes and clinical applications.
Collapse
Affiliation(s)
- Pingdewinde N. Sam
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Erica Avery
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Steven M. Claypool
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| |
Collapse
|
22
|
Naito T, Ercan B, Krshnan L, Triebl A, Koh DHZ, Wei FY, Tomizawa K, Torta FT, Wenk MR, Saheki Y. Movement of accessible plasma membrane cholesterol by the GRAMD1 lipid transfer protein complex. eLife 2019; 8:51401. [PMID: 31724953 PMCID: PMC6905856 DOI: 10.7554/elife.51401] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/13/2019] [Indexed: 12/18/2022] Open
Abstract
Cholesterol is a major structural component of the plasma membrane (PM). The majority of PM cholesterol forms complexes with other PM lipids, making it inaccessible for intracellular transport. Transition of PM cholesterol between accessible and inaccessible pools maintains cellular homeostasis, but how cells monitor the accessibility of PM cholesterol remains unclear. We show that endoplasmic reticulum (ER)-anchored lipid transfer proteins, the GRAMD1s, sense and transport accessible PM cholesterol to the ER. GRAMD1s bind to one another and populate ER-PM contacts by sensing a transient expansion of the accessible pool of PM cholesterol via their GRAM domains. They then facilitate the transport of this cholesterol via their StART-like domains. Cells that lack all three GRAMD1s exhibit striking expansion of the accessible pool of PM cholesterol as a result of less efficient PM to ER transport of accessible cholesterol. Thus, GRAMD1s facilitate the movement of accessible PM cholesterol to the ER in order to counteract an acute increase of PM cholesterol, thereby activating non-vesicular cholesterol transport. The human body contains trillions of cells. At the outer edge of each cell is the plasma membrane, which protects the cell from the external environment. This membrane is mostly made of fatty molecules known as lipids and about half of these lipids are specifically cholesterol. Human cells can either take up cholesterol that were obtained via the diet or produce it within a compartment of the cell called the endoplasmic reticulum. Cells need to monitor the cholesterol levels in both the endoplasmic reticulum and the plasma membrane in order to regulate the uptake or production of this lipid. For example, if there is too much of cholesterol in the plasma membrane, then the cell transports some to the endoplasmic reticulum to tell it to shut down cholesterol production. However, how these different areas of the cell communicate with each other, and transport cholesterol, has remained unclear. Naito et al. set out to look for key regulators of cholesterol transport and identified a group of endoplasmic reticulum proteins called GRAMD1 proteins. Cholesterol in the plasma membrane is either accessible or inaccessible, meaning it either can or cannot be moved back into the cell. The GRAMD1 proteins sense accessible cholesterol, and experiments with human cells grown in the laboratory showed that, specifically, the GRAMD1 proteins work together in a complex to sense accessible cholesterol at or near the plasma membrane. One particular part of the protein senses when the amount of accessible cholesterol reaches a certain level at the plasma membrane; when this threshold is reached, the complex flips a switch to start the transport of cholesterol to the endoplasmic reticulum and tell it to shut down cholesterol production. This coupling of sensing and transporting lipids by one protein complex also helps maintain the right ratio of accessible and inaccessible cholesterol in the plasma membrane to prevent cells from activating unwanted cell-signaling events. Getting rid of the GRAMD1 proteins in cells, or removing sensing part of these proteins, leads to inefficient transport of cholesterol. A better understanding of how GRAMD1 proteins sense the accessibility of cholesterol could potentially help identify new approaches to control cholesterol transport inside cells. This may in turn eventually lead to new treatments that counteract the defects in cholesterol metabolism seen in some forms of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease.
Collapse
Affiliation(s)
- Tomoki Naito
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Bilge Ercan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Logesvaran Krshnan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Alexander Triebl
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Dylan Hong Zheng Koh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Federico Tesio Torta
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Markus R Wenk
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| |
Collapse
|
23
|
Tugaeva KV, Sluchanko NN. Steroidogenic Acute Regulatory Protein: Structure, Functioning, and Regulation. BIOCHEMISTRY (MOSCOW) 2019; 84:S233-S253. [PMID: 31213205 DOI: 10.1134/s0006297919140141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Steroidogenesis takes place mainly in adrenal and gonadal cells that produce a variety of structurally similar hormones regulating numerous body functions. The rate-limiting stage of steroidogenesis is cholesterol delivery to the inner mitochondrial membrane, where it is converted by cytochrome P450scc into pregnenolone, a common precursor of all steroid hormones. The major role of supplying mitochondria with cholesterol belongs to steroidogenic acute regulatory protein (STARD1). STARD1, which is synthesized de novo as a precursor containing mitochondrial localization sequence and sterol-binding domain, significantly accelerates cholesterol transport and production of pregnenolone. Despite a tremendous interest in STARD1 fueled by its involvement in hereditary diseases and extensive efforts of numerous laboratories worldwide, many aspects of STARD1 structure, functioning, and regulation remain obscure and debatable. This review presents current concepts on the structure of STARD1 and other lipid transfer proteins, the role of STARD1 in steroidogenesis, and the mechanism of its functioning, as well as identifies the most controversial and least studied questions related to the activity of this protein.
Collapse
Affiliation(s)
- K V Tugaeva
- Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia. .,Lomonosov Moscow State University, Biological Faculty, Department of Biochemistry, Moscow, 119234, Russia
| | - N N Sluchanko
- Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia. .,Lomonosov Moscow State University, Biological Faculty, Department of Biophysics, Moscow, 119991, Russia
| |
Collapse
|
24
|
Rodriguez-Agudo D, Malacrida L, Kakiyama G, Sparrer T, Fortes C, Maceyka M, Subler MA, Windle JJ, Gratton E, Pandak WM, Gil G. StarD5: an ER stress protein regulates plasma membrane and intracellular cholesterol homeostasis. J Lipid Res 2019; 60:1087-1098. [PMID: 31015253 PMCID: PMC6547630 DOI: 10.1194/jlr.m091967] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/08/2019] [Indexed: 01/01/2023] Open
Abstract
How plasma membrane (PM) cholesterol is controlled is poorly understood. Ablation of the gene encoding the ER stress steroidogenic acute regulatory-related lipid transfer domain (StarD)5 leads to a decrease in PM cholesterol content, a decrease in cholesterol efflux, and an increase in intracellular neutral lipid accumulation in macrophages, the major cell type that expresses StarD5. ER stress increases StarD5 expression in mouse hepatocytes, which results in an increase in accessible PM cholesterol in WT but not in StarD5-/- hepatocytes. StarD5-/- mice store higher levels of cholesterol and triglycerides, which leads to altered expression of cholesterol-regulated genes. In vitro, a recombinant GST-StarD5 protein transfers cholesterol between synthetic liposomes. StarD5 overexpression leads to a marked increase in PM cholesterol. Phasor analysis of 6-dodecanoyl-2-dimethylaminonaphthalene fluorescence lifetime imaging microscopy data revealed an increase in PM fluidity in StarD5-/- macrophages. Taken together, these studies show that StarD5 is a stress-responsive protein that regulates PM cholesterol and intracellular cholesterol homeostasis.
Collapse
Affiliation(s)
- Daniel Rodriguez-Agudo
- Departments of Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- McGuire Veterans Affairs Medical Center, Richmond, VA 23248
| | - Leonel Malacrida
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California at Irvine, Irvine, CA 92697
- Area de Investigación Respiratoria, Departamento de Fisiopatologia, Hospital de Clinicas, Facultad de Medicina, Universidad de la Republica, Montevideo, Uruguay
| | - Genta Kakiyama
- Departments of Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- McGuire Veterans Affairs Medical Center, Richmond, VA 23248
| | - Tavis Sparrer
- Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Carolina Fortes
- Departments of Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- Departmento de Biologia Molecular y Bioquimica, Universidad de Malaga, Malaga, Spain
| | - Michael Maceyka
- Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Mark A Subler
- Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Jolene J Windle
- Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California at Irvine, Irvine, CA 92697
| | - William M Pandak
- Departments of Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- McGuire Veterans Affairs Medical Center, Richmond, VA 23248
| | - Gregorio Gil
- Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
- Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| |
Collapse
|
25
|
Luo J, Jiang LY, Yang H, Song BL. Intracellular Cholesterol Transport by Sterol Transfer Proteins at Membrane Contact Sites. Trends Biochem Sci 2019; 44:273-292. [DOI: 10.1016/j.tibs.2018.10.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/06/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022]
|
26
|
Analysis of diet-induced differential methylation, expression, and interactions of lncRNA and protein-coding genes in mouse liver. Sci Rep 2018; 8:11537. [PMID: 30069000 PMCID: PMC6070528 DOI: 10.1038/s41598-018-29993-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/29/2018] [Indexed: 12/11/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) regulate expression of protein-coding genes in cis through chromatin modifications including DNA methylation. Here we interrogated whether lncRNA genes may regulate transcription and methylation of their flanking or overlapping protein-coding genes in livers of mice exposed to a 12-week cholesterol-rich Western-style high fat diet (HFD) relative to a standard diet (STD). Deconvolution analysis of cell type-specific marker gene expression suggested similar hepatic cell type composition in HFD and STD livers. RNA-seq and validation by nCounter technology revealed differential expression of 14 lncRNA genes and 395 protein-coding genes enriched for functions in steroid/cholesterol synthesis, fatty acid metabolism, lipid localization, and circadian rhythm. While lncRNA and protein-coding genes were co-expressed in 53 lncRNA/protein-coding gene pairs, both were differentially expressed only in 4 lncRNA/protein-coding gene pairs, none of which included protein-coding genes in overrepresented pathways. Furthermore, 5-methylcytosine DNA immunoprecipitation sequencing and targeted bisulfite sequencing revealed no differential DNA methylation of genes in overrepresented pathways. These results suggest lncRNA/protein-coding gene interactions in cis play a minor role mediating hepatic expression of lipid metabolism/localization and circadian clock genes in response to chronic HFD feeding.
Collapse
|
27
|
Kumar KK, Devi BU, Neeraja P. Molecular activities and ligand-binding specificities of StAR-related lipid transfer domains: exploring integrated in silico methods and ensemble-docking approaches. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2018; 29:483-501. [PMID: 29688061 DOI: 10.1080/1062936x.2018.1462847] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
In this study, cholesterol biotransformation gene-set of human steroidogenic acute regulatory protein-related lipid transfer (START) domains were evaluated from high-throughput gene screening approaches. It was shown that STARD1, STARD3 and STARD4 proteins are better effective transporters of cholesterol than STARD5 and STARD6 domains. Docking studies show a strong agreement with gene ontology enrichment data. According to both complementary strategies, it was found that only STARD1, STARD3 and STARD4 are potentially involved in cholesterol biotransformation in mitochondria through Ω1-loop of C-terminal α4-helical domain. Ensemble docking assessment for a set of selected chemicals of protein-chemical networks has shown possible binding probabilities with START domains. Among those, reproductive toxicity evoked drugs (mifepristone), insecticides (rotenone), tobacco pulmonary carcinogens (benzo(a)pyrene) and endocrine disruptor chemicals (EDCs) including perfluorooctanesulfonic acid (PFOS) and aflatoxin B1 (AFB1) potentially bound with novel hotspot residues of the α4-helical domain. Compound representation space and clustering approaches reveal that the START proteins show more sensitivity with these lead scaffolds, so they could provide probable barrier assets in cholesterol and steroidogenic acute regulatory (StAR) binding and leads adverse consequences in steroidogenesis. These findings indicate potential START domains and their binding levels with toxic chemicals; sorted viewpoints could be useful as a promising way to identify chemicals with related steroidogenisis impacts on human health.
Collapse
Affiliation(s)
- K Kranthi Kumar
- a Department of Zoology , Sri Venkateswara University , Tirupati , 517502 - A.P . India
| | - B Uma Devi
- a Department of Zoology , Sri Venkateswara University , Tirupati , 517502 - A.P . India
| | - P Neeraja
- a Department of Zoology , Sri Venkateswara University , Tirupati , 517502 - A.P . India
| |
Collapse
|
28
|
Implication of STARD5 and cholesterol homeostasis disturbance in the endoplasmic reticulum stress-related response induced by pro-apoptotic aminosteroid RM-133. Pharmacol Res 2017; 128:52-60. [PMID: 29287690 DOI: 10.1016/j.phrs.2017.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 12/15/2017] [Accepted: 12/22/2017] [Indexed: 01/13/2023]
Abstract
The aminosteroid derivative RM-133 is an effective anticancer molecule for which proof of concept has been achieved in several mouse xenograph models (HL-60, MCF-7, PANC-1 and OVCAR-3). To promote this new family of molecules toward a clinical phase 1 trial, the mechanism of action governing the anticancer properties of the representative candidate RM-133 needs to be characterized. In vitro experiments were first used to determine that RM-133 causes apoptosis in cancer cells. Then, using proteomic and transcriptomic experiments, RM-133 cytotoxicity was proven to be achieved via the endoplasmic reticulum (ER)-related apoptosis, which characterizes RM-133 as an endoplasmic reticulum stress aggravator (ERSA) anticancer drug. Furthermore, an shRNA-genome-wide screening has permitted to identify the steroidogenic acute regulator-related lipid transfer protein 5 (STARD5) as a major player in the RM-133 ER-related apoptosis mechanism, which was validated by an in vitro binding experiment. Altogether, the results presented herein suggest that RM-133 provokes a disturbance of cholesterol homeostasis via the implication of STARD5, which delivers an ERSA molecule to the ER. These results will be a springboard for RM-133 in its path toward clinical use.
Collapse
|
29
|
Kranc W, Brązert M, Ożegowska K, Nawrocki MJ, Budna J, Celichowski P, Dyszkiewicz-Konwińska M, Jankowski M, Jeseta M, Pawelczyk L, Bruska M, Nowicki M, Zabel M, Kempisty B. Expression Profile of Genes Regulating Steroid Biosynthesis and Metabolism in Human Ovarian Granulosa Cells-A Primary Culture Approach. Int J Mol Sci 2017; 18:ijms18122673. [PMID: 29232835 PMCID: PMC5751275 DOI: 10.3390/ijms18122673] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/04/2017] [Accepted: 12/08/2017] [Indexed: 01/22/2023] Open
Abstract
Because of the deep involvement of granulosa cells in the processes surrounding the cycles of menstruation and reproduction, there is a great need for a deeper understanding of the ways in which they function during the various stages of those cycles. One of the main ways in which the granulosa cells influence the numerous sex associated processes is hormonal interaction. Expression of steroid sex hormones influences a range of both primary and secondary sexual characteristics, as well as regulate the processes of oogenesis, folliculogenesis, ovulation, and pregnancy. Understanding of the exact molecular mechanisms underlying those processes could not only provide us with deep insight into the regulation of the reproductive cycle, but also create new clinical advantages in detection and treatment of various diseases associated with sex hormone abnormalities. We have used the microarray approach validated by RT-qPCR, to analyze the patterns of gene expression in primary cultures of human granulosa cells at days 1, 7, 15, and 30 of said cultures. We have especially focused on genes belonging to ontology groups associated with steroid biosynthesis and metabolism, namely “Regulation of steroid biosynthesis process” and “Regulation of steroid metabolic process”. Eleven genes have been chosen, as they exhibited major change under a culture condition. Out of those, ten genes, namely STAR, SCAP, POR, SREBF1, GFI1, SEC14L2, STARD4, INSIG1, DHCR7, and IL1B, belong to both groups. Patterns of expression of those genes were analyzed, along with brief description of their functions. That analysis helped us achieve a better understanding of the exact molecular processes underlying steroid biosynthesis and metabolism in human granulosa cells.
Collapse
Affiliation(s)
- Wiesława Kranc
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Maciej Brązert
- Division of Infertility and Reproductive Endocrinology, Department of Gynecology, Obstetrics and Gynecological Oncology, Poznan University of Medical Sciences, 60-101 Poznan, Poland.
| | - Katarzyna Ożegowska
- Division of Infertility and Reproductive Endocrinology, Department of Gynecology, Obstetrics and Gynecological Oncology, Poznan University of Medical Sciences, 60-101 Poznan, Poland.
| | - Mariusz J Nawrocki
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Joanna Budna
- Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Piotr Celichowski
- Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Marta Dyszkiewicz-Konwińska
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
- Department of Biomaterials and Experimental Dentistry, Poznan University of Medical Sciences, 60-812 Poznan, Poland.
| | - Maurycy Jankowski
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Michal Jeseta
- Department of Obstetrics and Gynecology, University Hospital and Masaryk University, 625 00 Brno, Czech Republic.
| | - Leszek Pawelczyk
- Division of Infertility and Reproductive Endocrinology, Department of Gynecology, Obstetrics and Gynecological Oncology, Poznan University of Medical Sciences, 60-101 Poznan, Poland.
| | - Małgorzata Bruska
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Michał Nowicki
- Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
| | - Maciej Zabel
- Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
- Department of Histology and Embryology, Wroclaw Medical University, 50-368 Wroclaw, Poland.
| | - Bartosz Kempisty
- Department of Anatomy, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
- Department of Histology and Embryology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
- Department of Obstetrics and Gynecology, University Hospital and Masaryk University, 625 00 Brno, Czech Republic.
| |
Collapse
|
30
|
Identification of genome-wide SNP-SNP interactions associated with important traits in chicken. BMC Genomics 2017; 18:892. [PMID: 29162033 PMCID: PMC5698929 DOI: 10.1186/s12864-017-4252-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND In addition to additive genetic effects, epistatic interactions can play key roles in the control of phenotypic variation of traits of interest. In the current study, 475 male birds from lean and fat chicken lines were utilized as a resource population to detect significant epistatic effects associated with growth and carcass traits. RESULTS A total of 421 significant epistatic effects were associated with testis weight (TeW), from which 11 sub-networks (Sub-network1 to Sub-network11) were constructed. In Sub-network1, which was the biggest network, there was an interaction between GGA21 and GGAZ. Three genes on GGA21 (SDHB, PARK7 and VAMP3) and nine genes (AGTPBP1, CAMK4, CDC14B, FANCC, FBP1, GNAQ, PTCH1, ROR2 and STARD4) on GGAZ that might be potentially important candidate genes for testis growth and development were detected based on the annotated gene function. In Sub-network2, there was a SNP on GGA19 that interacted with 8 SNPs located on GGA10. The SNP (Gga_rs15834332) on GGA19 was located between C-C motif chemokine ligand 5 (CCL5) and MIR142. There were 32 Refgenes on GGA10, including TCF12 which is predicted to be a target gene of miR-142-5p. We hypothesize that miR-142-5p and TCF12 may interact with one another to regulate testis growth and development. Two genes (CDH12 and WNT8A) in the same cadherin signaling pathway were implicated as potentially important genes in the control of metatarsus circumference (MeC). There were no significant epistatic effects identified for the other carcass and growth traits, e.g. heart weight (HW), liver weight (LW), spleen weight (SW), muscular and glandular stomach weight (MGSW), carcass weight (CW), body weight (BW1, BW3, BW5, BW7), chest width (ChWi), metatarsus length (MeL). CONCLUSIONS The results of the current study are helpful to better understand the genetic basis of carcass and growth traits, especially for testis growth and development in broilers.
Collapse
|
31
|
Stefan CJ, Trimble WS, Grinstein S, Drin G, Reinisch K, De Camilli P, Cohen S, Valm AM, Lippincott-Schwartz J, Levine TP, Iaea DB, Maxfield FR, Futter CE, Eden ER, Judith D, van Vliet AR, Agostinis P, Tooze SA, Sugiura A, McBride HM. Membrane dynamics and organelle biogenesis-lipid pipelines and vesicular carriers. BMC Biol 2017; 15:102. [PMID: 29089042 PMCID: PMC5663033 DOI: 10.1186/s12915-017-0432-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Discoveries spanning several decades have pointed to vital membrane lipid trafficking pathways involving both vesicular and non-vesicular carriers. But the relative contributions for distinct membrane delivery pathways in cell growth and organelle biogenesis continue to be a puzzle. This is because lipids flow from many sources and across many paths via transport vesicles, non-vesicular transfer proteins, and dynamic interactions between organelles at membrane contact sites. This forum presents our latest understanding, appreciation, and queries regarding the lipid transport mechanisms necessary to drive membrane expansion during organelle biogenesis and cell growth.
Collapse
Affiliation(s)
- Christopher J. Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - William S. Trimble
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Guillaume Drin
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Karin Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Pietro De Camilli
- Department of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Kavli Institute for Neuroscience and Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510 USA
| | | | | | | | - Tim P. Levine
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - David B. Iaea
- Genentech, 1 DNA Way, South San Francisco, CA 94080 USA
| | - Frederick R. Maxfield
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065 USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Emily R. Eden
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Delphine Judith
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Alexander R. van Vliet
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Ayumu Sugiura
- Kobe University Graduate School of Medicine, 1-5-6 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 Japan
| | - Heidi M. McBride
- Montreal Neurological Institute, McGill University, 3801 University Avenue, Montreal, Quebec H3A 2B4 Canada
| |
Collapse
|
32
|
Iaea DB, Mao S, Lund FW, Maxfield FR. Role of STARD4 in sterol transport between the endocytic recycling compartment and the plasma membrane. Mol Biol Cell 2017; 28:1111-1122. [PMID: 28209730 PMCID: PMC5391187 DOI: 10.1091/mbc.e16-07-0499] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/03/2017] [Accepted: 02/08/2017] [Indexed: 11/23/2022] Open
Abstract
The kinetics of sterol transport between the plasma membrane and the endocytic recycling compartment is measured using fluorescence microscopy. STARD4, a small, soluble sterol transport protein, is responsible for 25% of the total transport and 33% of nonvesicular transport. Elevated cholesterol dramatically increases sterol transport rate constants. Cholesterol is an essential constituent of membranes in mammalian cells. The plasma membrane and the endocytic recycling compartment (ERC) are both highly enriched in cholesterol. The abundance and distribution of cholesterol among organelles are tightly controlled by a combination of mechanisms involving vesicular and nonvesicular sterol transport processes. Using the fluorescent cholesterol analogue dehydroergosterol, we examined sterol transport between the plasma membrane and the ERC using fluorescence recovery after photobleaching and a novel sterol efflux assay. We found that sterol transport between these organelles in a U2OS cell line has a t1/2 =12–15 min. Approximately 70% of sterol transport is ATP independent and therefore is nonvesicular. Increasing cellular cholesterol levels dramatically increases bidirectional transport rate constants, but decreases in cholesterol levels have only a modest effect. A soluble sterol transport protein, STARD4, accounts for ∼25% of total sterol transport and ∼33% of nonvesicular sterol transport between the plasma membrane and ERC. This study shows that nonvesicular sterol transport mechanisms and STARD4 in particular account for a large fraction of sterol transport between the plasma membrane and the ERC.
Collapse
Affiliation(s)
- David B Iaea
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065.,Weill Cornell Medical College, Rockefeller University, and Memorial Sloan-Kettering Cancer Center Tri-Institutional Chemical Biology Program, New York, NY 10065
| | - Shu Mao
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Frederik W Lund
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065 .,Weill Cornell Medical College, Rockefeller University, and Memorial Sloan-Kettering Cancer Center Tri-Institutional Chemical Biology Program, New York, NY 10065
| |
Collapse
|
33
|
Tsai YY, Rainey WE, Bollag WB. Very low-density lipoprotein (VLDL)-induced signals mediating aldosterone production. J Endocrinol 2017; 232:R115-R129. [PMID: 27913572 PMCID: PMC8310676 DOI: 10.1530/joe-16-0237] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 01/14/2023]
Abstract
Aldosterone, secreted by the adrenal zona glomerulosa, enhances sodium retention, thus increasing blood volume and pressure. Excessive production of aldosterone results in high blood pressure and contributes to cardiovascular and renal disease, stroke and visual loss. Hypertension is also associated with obesity, which is correlated with other serious health risks as well. Although weight gain is associated with increased blood pressure, the mechanism by which excess fat deposits increase blood pressure remains unclear. Several studies have suggested that aldosterone levels are elevated with obesity and may represent a link between obesity and hypertension. In addition to hypertension, obese patients typically have dyslipidemia, including elevated serum levels of very low-density lipoprotein (VLDL). VLDL, which functions to transport triglycerides from the liver to peripheral tissues, has been demonstrated to stimulate aldosterone production. Recent studies suggest that the signaling pathways activated by VLDL are similar to those utilized by AngII. Thus, VLDL increases cytosolic calcium levels and stimulates phospholipase D (PLD) activity to result in the induction of steroidogenic acute regulatory (StAR) protein and aldosterone synthase (CYP11B2) expression. These effects seem to be mediated by the ability of VLDL to increase the phosphorylation (activation) of their regulatory transcription factors, such as the cAMP response element-binding (CREB) protein family of transcription factors. Thus, research into the pathways by which VLDL stimulates aldosterone production may identify novel targets for the development of therapies for the treatment of hypertension, particularly those associated with obesity, and other aldosterone-modulated pathologies.
Collapse
Affiliation(s)
- Ying-Ying Tsai
- Department of PhysiologyMedical College of Georgia at Augusta University (formerly Georgia Regents University), Augusta, Georgia, USA
| | - William E Rainey
- Departments of Molecular & Integrative Physiology and Internal MedicineUniversity of Michigan, Ann Arbor, Michigan, USA
| | - Wendy B Bollag
- Department of PhysiologyMedical College of Georgia at Augusta University (formerly Georgia Regents University), Augusta, Georgia, USA
- Charlie Norwood VA Medical CenterOne Freedom Way, Augusta, Georgia, USA
| |
Collapse
|
34
|
Miller WL. Disorders in the initial steps of steroid hormone synthesis. J Steroid Biochem Mol Biol 2017; 165:18-37. [PMID: 26960203 DOI: 10.1016/j.jsbmb.2016.03.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 12/29/2022]
Abstract
Steroidogenesis begins with cellular internalization of low-density lipoprotein particles and subsequent intracellular processing of cholesterol. Disorders in these steps include Adrenoleukodystrophy, Wolman Disease and its milder variant Cholesterol Ester Storage Disease, and Niemann-Pick Type C Disease, all of which may present with adrenal insufficiency. The means by which cholesterol is directed to steroidogenic mitochondria remains incompletely understood. Once cholesterol reaches the outer mitochondrial membrane, its delivery to the inner mitochondrial membrane is regulated by the steroidogenic acute regulatory protein (StAR). Severe StAR mutations cause classic congenital lipoid adrenal hyperplasia, characterized by lipid accumulation in the adrenal, adrenal insufficiency, and disordered sexual development in 46,XY individuals. The lipoid CAH phenotype, including spontaneous puberty in 46,XX females, is explained by a two-hit model. StAR mutations that retain partial function cause a milder, non-classic disease characterized by glucocorticoid deficiency, with lesser disorders of mineralocorticoid and sex steroid synthesis. Once inside the mitochondria, cholesterol is converted to pregnenolone by the cholesterol side-chain cleavage enzyme, P450scc, encoded by the CYP11A1 gene. Rare patients with mutations of P450scc are clinically and hormonally indistinguishable from those with lipoid CAH, and may also present as milder non-classic disease. Patients with P450scc defects do not have the massive adrenal hyperplasia that characterizes lipoid CAH, but adrenal imaging may occasionally fail to distinguish these, necessitating DNA sequencing.
Collapse
Affiliation(s)
- Walter L Miller
- Center for Reproductive Sciences, University of California, San Francisco, CA 94143-0556, United States.
| |
Collapse
|
35
|
Khoury K, Barbar E, Ainmelk Y, Ouellet A, Lavigne P, LeHoux JG. Thirty-Eight-Year Follow-Up of Two Sibling Lipoid Congenital Adrenal Hyperplasia Patients Due to Homozygous Steroidogenic Acute Regulatory (STARD1) Protein Mutation. Molecular Structure and Modeling of the STARD1 L275P Mutation. Front Neurosci 2016; 10:527. [PMID: 27917104 PMCID: PMC5116571 DOI: 10.3389/fnins.2016.00527] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/31/2016] [Indexed: 11/13/2022] Open
Abstract
Objective: Review the impact of StAR (STARD1) mutations on steroidogenesis and fertility in LCAH patients. Examine the endocrine mechanisms underlying the pathology of the disorder and the appropriate therapy for promoting fertility and pregnancies. Design: Published data in the literature and a detailed 38-year follow-up of two sibling LCAH patients. Molecular structure and modeling of the STARD1 L275P mutation. Setting: University hospital. Patients: Patient A (46,XY female phenotype) and patient B (46,XX female) with LCAH bearing the L275P mutation in STARD1. Interventions: Since early-age diagnosis, both patients underwent corticoid replacement therapy. Patient A received estrogen therapy at pubertal age. Clomiphene therapy was given to Patient B to induce ovulation. Pregnancies were protected with progesterone administration. Main Outcome Measures: Clinical and molecular assessment of adrenal and gonadal functions. Results: Both patients have classic manifestations of corticosteroid deficiency observed in LCAH. Time of onset and severity were different. Patient A developed into a female phenotype due to early and severe damage of Leydig cells. Patient B started a progressive pubertal development, menarche and regular non-ovulatory cycle. She was able to have successful pregnancies. Conclusions: Understanding the molecular structure and function of STARD1 in all steroidogenic tissues is the key for comprehending the heterogeneous clinical manifestations of LCAH, and the development of an appropriate strategy for the induction of ovulation and protecting pregnancies in this disease.
Collapse
Affiliation(s)
- Khalil Khoury
- Department of Pediatrics, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Elie Barbar
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Youssef Ainmelk
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Annie Ouellet
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Pierre Lavigne
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Jean-Guy LeHoux
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| |
Collapse
|
36
|
Garg D, Merhi Z. Relationship between Advanced Glycation End Products and Steroidogenesis in PCOS. Reprod Biol Endocrinol 2016; 14:71. [PMID: 27769286 PMCID: PMC5073880 DOI: 10.1186/s12958-016-0205-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/14/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Women with PCOS have elevated levels of the harmful Advanced Glycation End Products (AGEs), which are highly reactive molecules formed after glycation of lipids and proteins. Additionally, AGEs accumulate in the ovaries of women with PCOS potentially contributing to the well-documented abnormal steroidogenesis and folliculogenesis. MAIN BODY A systematic review of articles and abstracts available in PubMed was conducted and presented in a systemic manner. This article reports changes in steroidogenic enzyme activity in granulosa and theca cells in PCOS and PCOS-models. It also described the changes in AGEs and their receptors in the ovaries of women with PCOS and presents the underlying mechanism(s) whereby AGEs could be responsible for the PCOS-related changes in granulosa and theca cell function thus adversely impacting steroidogenesis and follicular development. AGEs are associated with hyperandrogenism in PCOS possibly by altering the activity of various enzymes such as cholesterol side-chain cleavage enzyme cytochrome P450, steroidogenic acute regulatory protein, 17α-hydroxylase, and 3β-hydroxysteroid dehydrogenase. AGEs also affect luteinizing hormone receptor and anti-Mullerian hormone receptor expression as well as their signaling pathways in granulosa cells. CONCLUSIONS A better understanding of how AGEs alter granulosa and theca cell function is likely to contribute meaningfully to a conceptual framework whereby new interventions to prevent and/or treat ovarian dysfunction in PCOS can ultimately be developed.
Collapse
Affiliation(s)
- Deepika Garg
- Department of Obstetrics and Gynecology, Maimonides Medical Center, Brooklyn, NY 11219 USA
| | - Zaher Merhi
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, NYU School of Medicine, 180 Varick Street, sixth floor, New York City, NY 11014 USA
| |
Collapse
|
37
|
Intracellular cholesterol transport proteins: roles in health and disease. Clin Sci (Lond) 2016; 130:1843-59. [DOI: 10.1042/cs20160339] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/12/2016] [Indexed: 12/13/2022]
Abstract
Effective cholesterol homoeostasis is essential in maintaining cellular function, and this is achieved by a network of lipid-responsive nuclear transcription factors, and enzymes, receptors and transporters subject to post-transcriptional and post-translational regulation, whereas loss of these elegant, tightly regulated homoeostatic responses is integral to disease pathologies. Recent data suggest that sterol-binding sensors, exchangers and transporters contribute to regulation of cellular cholesterol homoeostasis and that genetic overexpression or deletion, or mutations, in a number of these proteins are linked with diseases, including atherosclerosis, dyslipidaemia, diabetes, congenital lipoid adrenal hyperplasia, cancer, autosomal dominant hearing loss and male infertility. This review focuses on current evidence exploring the function of members of the ‘START’ (steroidogenic acute regulatory protein-related lipid transfer) and ‘ORP’ (oxysterol-binding protein-related proteins) families of sterol-binding proteins in sterol homoeostasis in eukaryotic cells, and the evidence that they represent valid therapeutic targets to alleviate human disease.
Collapse
|
38
|
Elustondo P, Martin LA, Karten B. Mitochondrial cholesterol import. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:90-101. [PMID: 27565112 DOI: 10.1016/j.bbalip.2016.08.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023]
Abstract
All animal subcellular membranes require cholesterol, which influences membrane fluidity and permeability, fission and fusion processes, and membrane protein function. The distribution of cholesterol among subcellular membranes is highly heterogeneous and the cholesterol content of each membrane must be carefully regulated. Compared to other subcellular membranes, mitochondrial membranes are cholesterol-poor, particularly the inner mitochondrial membrane (IMM). As a result, steroidogenesis can be controlled through the delivery of cholesterol to the IMM, where it is converted to pregnenolone. The low basal levels of cholesterol also make mitochondria sensitive to changes in cholesterol content, which can have a relatively large impact on the biophysical and functional characteristics of mitochondrial membranes. Increased mitochondrial cholesterol levels have been observed in diverse pathological conditions including cancer, steatohepatitis, Alzheimer disease and Niemann-Pick Type C1-deficiency, and are associated with increased oxidative stress, impaired oxidative phosphorylation, and changes in the susceptibility to apoptosis, among other alterations in mitochondrial function. Mitochondria are not included in the vesicular trafficking network; therefore, cholesterol transport to mitochondria is mostly achieved through the activity of lipid transfer proteins at membrane contact sites or by cytosolic, diffusible lipid transfer proteins. Here we will give an overview of the main mechanisms involved in mitochondrial cholesterol import, focusing on the steroidogenic acute regulatory protein StAR/STARD1 and other members of the StAR-related lipid transfer (START) domain protein family, and we will discuss how changes in mitochondrial cholesterol levels can arise and affect mitochondrial function. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Collapse
Affiliation(s)
- Pia Elustondo
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Laura A Martin
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Barbara Karten
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| |
Collapse
|
39
|
Nielsen AY, Gjerstorff MF. Ectopic Expression of Testis Germ Cell Proteins in Cancer and Its Potential Role in Genomic Instability. Int J Mol Sci 2016; 17:E890. [PMID: 27275820 PMCID: PMC4926424 DOI: 10.3390/ijms17060890] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/23/2016] [Accepted: 06/01/2016] [Indexed: 12/18/2022] Open
Abstract
Genomic instability is a hallmark of human cancer and an enabling factor for the genetic alterations that drive cancer development. The processes involved in genomic instability resemble those of meiosis, where genetic material is interchanged between homologous chromosomes. In most types of human cancer, epigenetic changes, including hypomethylation of gene promoters, lead to the ectopic expression of a large number of proteins normally restricted to the germ cells of the testis. Due to the similarities between meiosis and genomic instability, it has been proposed that activation of meiotic programs may drive genomic instability in cancer cells. Some germ cell proteins with ectopic expression in cancer cells indeed seem to promote genomic instability, while others reduce polyploidy and maintain mitotic fidelity. Furthermore, oncogenic germ cell proteins may indirectly contribute to genomic instability through induction of replication stress, similar to classic oncogenes. Thus, current evidence suggests that testis germ cell proteins are implicated in cancer development by regulating genomic instability during tumorigenesis, and these proteins therefore represent promising targets for novel therapeutic strategies.
Collapse
Affiliation(s)
- Aaraby Yoheswaran Nielsen
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, Odense DK-5000, Denmark.
| | - Morten Frier Gjerstorff
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, Odense DK-5000, Denmark.
| |
Collapse
|
40
|
Maxfield FR, Iaea DB, Pipalia NH. Role of STARD4 and NPC1 in intracellular sterol transport. Biochem Cell Biol 2016; 94:499-506. [PMID: 27421092 DOI: 10.1139/bcb-2015-0154] [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] [Indexed: 12/15/2022] Open
Abstract
Cholesterol plays an important role in determining the biophysical properties of membranes in mammalian cells, and the concentration of cholesterol in membranes is tightly regulated. Cholesterol moves among membrane organelles by a combination of vesicular and nonvesicular transport pathways, but the details of these transport pathways are not well understood. In this review, we discuss the mechanisms for nonvesicular sterol transport with an emphasis on the role of STARD4, a small, soluble, cytoplasmic sterol transport protein. STARD4 can rapidly equilibrate sterol between membranes, especially membranes with anionic lipid headgroups. We also discuss the sterol transport in late endosomes and lysosomes, which is mediated by a soluble protein, NPC2, and a membrane protein, NPC1. Homozygous mutations in these proteins lead to a lysosomal lipid storage disorder, Niemann-Pick disease type C. Many of the disease-causing mutations in NPC1 are associated with degradation of the mutant NPC1 proteins in the endoplasmic reticulum. Several histone deacetylase inhibitors have been found to rescue the premature degradation of the mutant NPC1 proteins, and one of these is now in a small clinical trial.
Collapse
Affiliation(s)
- Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.,Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - David B Iaea
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.,Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Nina H Pipalia
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.,Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| |
Collapse
|
41
|
Abstract
Sterols are a critical component of cell membranes of eukaryotes. In mammalian cells there is approximately a six-fold range in the cholesterol content in various organelles. The cholesterol content of membranes plays an important role in organizing membranes for signal transduction and protein trafficking as well as in modulating the physiochemical properties of membranes. Cholesterol trafficking among organelles is highly dynamic and is mediated by both vesicular and non-vesicular processes. Several proteins have been proposed to mediate inter-organelle trafficking of cholesterol. However, several aspects of the mechanisms involved in regulating trafficking and distribution of cholesterol remain to be elucidated. In the present chapter, we discuss the cellular mechanisms involved in cholesterol distribution and the trafficking processes involved in maintaining sterol homoeostasis.
Collapse
|
42
|
Abstract
The steroidogenic acute regulatory protein-related lipid transfer (START) domain family is defined by a conserved 210-amino acid sequence that folds into an α/β helix-grip structure. Members of this protein family bind a variety of ligands, including cholesterol, phospholipids, sphingolipids, and bile acids, with putative roles in nonvesicular lipid transport, metabolism, and cell signaling. Among the soluble START proteins, STARD4 is expressed in most tissues and has previously been shown to transfer sterol, but the molecular mechanisms of membrane interaction and sterol binding remain unclear. In this work, we use biochemical techniques to characterize regions of STARD4 and determine their role in membrane interaction and sterol binding. Our results show that STARD4 interacts with anionic membranes through a surface-exposed basic patch and that introducing a mutation (L124D) into the Omega-1 (Ω1) loop, which covers the sterol binding pocket, attenuates sterol transfer activity. To gain insight into the attenuating mechanism of the L124D mutation, we conducted structural and biophysical studies of wild-type and L124D STARD4. These studies show that the L124D mutation reduces the conformational flexibility of the protein, resulting in a diminished level of membrane interaction and sterol transfer. These studies also reveal that the C-terminal α-helix, and not the Ω1 loop, partitions into the membrane bilayer. On the basis of these observations, we propose a model of STARD4 membrane interaction and sterol binding and release that requires dynamic movement of both the Ω1 loop and membrane insertion of the C-terminal α-helix.
Collapse
Affiliation(s)
- David
B. Iaea
- Department
of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, United States,Weill Cornell Medical
College, Rockefeller University, and Memorial Sloan-Kettering Cancer
Center Tri-Institutional Chemical Biology Program, New York, New York 10065, United States
| | - Igor Dikiy
- Department
of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, United States
| | - Irene Kiburu
- Department
of Physiology and Biophysics, Weill Cornell
Medical College, 1300
York Avenue, New York, New
York 10065, United
States
| | - David Eliezer
- Department
of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, United States,Weill Cornell Medical
College, Rockefeller University, and Memorial Sloan-Kettering Cancer
Center Tri-Institutional Chemical Biology Program, New York, New York 10065, United States
| | - Frederick R. Maxfield
- Department
of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, United States,Weill Cornell Medical
College, Rockefeller University, and Memorial Sloan-Kettering Cancer
Center Tri-Institutional Chemical Biology Program, New York, New York 10065, United States,E-mail: . Telephone: (212) 746-6405. Fax: (212) 746-8875
| |
Collapse
|
43
|
Létourneau D, Lefebvre A, Lavigne P, LeHoux JG. The binding site specificity of STARD4 subfamily: Breaking the cholesterol paradigm. Mol Cell Endocrinol 2015; 408:53-61. [PMID: 25542846 DOI: 10.1016/j.mce.2014.12.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 11/16/2022]
Abstract
Steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domain proteins display diverse expression patterns and cellular localisations. They bind a large variety of lipids and sterols and are involved in lipid metabolism, lipid transfer and cell signalling. The START domain tertiary structure is an α-helix/β-grip fold module of approximately 210 amino acids delimiting an internal cavity forming the binding site. However, the determinants that dictate ligand specificity and the mechanism of ligand entry and exit are ill-defined. Herein, we review and discuss the current knowledge on ligand specificity and binding mechanism of START domains. More specifically, we highlight that the conserved residues of STARD1, STARD3, STARD4, STARD5 and STARD6 START domains binding sterol play an important structural role for the global protein fold, whereas the residues forming the cavity that fits the shape of their respective ligand are divergent, suggesting their participation in ligand specificity. We also explore the potential binding of steroids to STARD6 in the context of ligand selectivity.
Collapse
Affiliation(s)
- Danny Létourneau
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Andrée Lefebvre
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Pierre Lavigne
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Guy LeHoux
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
| |
Collapse
|
44
|
Izem L, Greene DJ, Bialkowska K, Morton RE. Overexpression of full-length cholesteryl ester transfer protein in SW872 cells reduces lipid accumulation. J Lipid Res 2015; 56:515-525. [PMID: 25593327 DOI: 10.1194/jlr.m053678] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cells produce two cholesteryl ester transfer protein (CETP) isoforms, full-length and a shorter variant produced by alternative splicing. Blocking synthesis of both isoforms disrupts lipid metabolism and storage. To further define the role of CETP in cellular lipid metabolism, we stably overexpressed full-length CETP in SW872 cells. These CETP(+) cells had several-fold higher intracellular CETP and accumulated 50% less TG due to a 26% decrease in TG synthesis and 2.5-fold higher TG turnover rate. Reduced TG synthesis was due to decreased fatty acid uptake and impaired conversion of diglyceride to TG even though diacylglycerol acyltransferase activity was normal. Sterol-regulatory element binding protein 1 mRNA levels were normal, and although PPARγ expression was reduced, the expression of several of its target genes including adipocyte triglyceride lipase, FASN, and APOE was normal. CETP(+) cells contained smaller lipid droplets, consistent with their higher levels of perilipin protein family (PLIN) 3 compared with PLIN1 and PLIN2. Intracellular CETP was mostly associated with the endoplasmic reticulum, although CETP near lipid droplets poorly colocalized with this membrane. A small pool of CETP resided in the cytoplasm, and a subfraction coisolated with lipid droplets. These data show that overexpression of full-length CETP disrupts lipid homeostasis resulting in the formation of smaller, more metabolically active lipid droplets.
Collapse
Affiliation(s)
- Lahoucine Izem
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Diane J Greene
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Katarzyna Bialkowska
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - Richard E Morton
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195.
| |
Collapse
|
45
|
Mitochondrial cholesterol: mechanisms of import and effects on mitochondrial function. J Bioenerg Biomembr 2014; 48:137-51. [PMID: 25425472 DOI: 10.1007/s10863-014-9592-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/14/2014] [Indexed: 12/23/2022]
Abstract
Mitochondria require cholesterol for biogenesis and membrane maintenance, and for the synthesis of steroids, oxysterols and hepatic bile acids. Multiple pathways mediate the transport of cholesterol from different subcellular pools to mitochondria. In steroidogenic cells, the steroidogenic acute regulatory protein (StAR) interacts with a mitochondrial protein complex to mediate cholesterol delivery to the inner mitochondrial membrane for conversion to pregnenolone. In non-steroidogenic cells, several members of a protein family defined by the presence of a StAR-related lipid transfer (START) domain play key roles in the delivery of cholesterol to mitochondrial membranes. Subdomains of the endoplasmic reticulum (ER), termed mitochondria-associated ER membranes (MAM), form membrane contact sites with mitochondria and may contribute to the transport of ER cholesterol to mitochondria, either independently or in conjunction with lipid-transfer proteins. Model systems of mitochondria enriched with cholesterol in vitro and mitochondria isolated from cells with (patho)physiological mitochondrial cholesterol accumulation clearly demonstrate that mitochondrial cholesterol levels affect mitochondrial function. Increased mitochondrial cholesterol levels have been observed in several diseases, including cancer, ischemia, steatohepatitis and neurodegenerative diseases, and influence disease pathology. Hence, a deeper understanding of the mechanisms maintaining mitochondrial cholesterol homeostasis may reveal additional targets for therapeutic intervention. Here we give a brief overview of mitochondrial cholesterol import in steroidogenic cells, and then focus on cholesterol trafficking pathways that deliver cholesterol to mitochondrial membranes in non-steroidogenic cells. We also briefly discuss the consequences of increased mitochondrial cholesterol levels on mitochondrial function and their potential role in disease pathology.
Collapse
|
46
|
Yamaguchi T, Koizumi K, Arai M, Tamura K, Iijima T, Horiguchi SI, Miyaki M. A large deletion of chromosome 5q22.1-22.2 associated with sparse type of familial adenomatous polyposis: report of a case. Jpn J Clin Oncol 2014; 44:1243-7. [PMID: 25324480 DOI: 10.1093/jjco/hyu150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The proband was a 32-year-old man with sparse type of familial adenomatous polyposis with fundic gland and duodenal polyps and congenital hypertrophy of the retinal pigment epithelium without osteoma, dental abnormalities and desmoid tumors. Direct DNA sequencing did not detect germline mutations in any APC exon. However, using the multiplex ligation-dependent probe amplification method, we detected germline deletions of all APC exons. Using dual-color fluorescence in situ hybridization, we identified germline deletion of locus 5q22.1-22.2 that includes APC. Analysis of colorectal tumors identified somatic APC mutations in the cluster region in all polyps, but no loss of heterozygosity was detected in any polyp.
Collapse
Affiliation(s)
- Tatsuro Yamaguchi
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Koichi Koizumi
- Department of Gastroenterology, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Masami Arai
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Kazuo Tamura
- Major in Science, Graduate School of Science and Engineering Research, Kinki University, Higashiosaka
| | - Takeru Iijima
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| | - Shin-Ichiro Horiguchi
- Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan
| | - Michiko Miyaki
- Hereditary Tumor Research Project, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo
| |
Collapse
|
47
|
Hu S, Liu H, Pan Z, Xia L, Dong X, Li L, Xu F, He H, Wang J. Molecular cloning, expression profile and transcriptional modulation of two splice variants of very low density lipoprotein receptor during ovarian follicle development in geese (Anser cygnoide). Anim Reprod Sci 2014; 149:281-96. [DOI: 10.1016/j.anireprosci.2014.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 10/25/2022]
|
48
|
Zaidi SK, Shen WJ, Bittner S, Bittner A, McLean MP, Han J, Davis RJ, Kraemer FB, Azhar S. p38 MAPK regulates steroidogenesis through transcriptional repression of STAR gene. J Mol Endocrinol 2014; 53:1-16. [PMID: 24780837 PMCID: PMC4077990 DOI: 10.1530/jme-13-0287] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
STAR/StarD1, part of a protein complex, mediates the transport of cholesterol from the outer to inner mitochondrial membrane, which is the rate-limiting step for steroidogenesis, and where steroid hormone synthesis begins. Herein, we examined the role of oxidant-sensitive p38 MAPKs in the regulation of STAR gene transcription, using model steroidogenic cell lines. Our data indicate that oxidant activation of p38 MAPK exhibits a negative regulatory role in the induction of functional expression of STAR, as evidenced by enhanced induction of STAR (mRNA/protein) expression and increased steroidogenesis during pharmacological inhibition of p38 MAPK or in cells with increased transient overexpression of a dominant-negative (dn) form of p38 MAPKα or p38 MAPKβ. Studies with rat Star-promoter demonstrated that overexpression of p38 MAPKα-wt, -β, or -γ significantly reduced both basal and cAMP-sensitive promoter activity. In contrast, overexpression of p38 MAPKα-dn, -β, or -γ enhanced the Star promoter activity under basal conditions and in response to cAMP stimulation. Use of various constitutively active and dn constructs and designer knock-out cell lines demonstrated that MKK3 and MKK6, the upstream activators of p38 MAPKs, play a role in p38 MAPKα-mediated inhibition of Star promoter activity. In addition, our studies raised the possibility of CREB being a potential target of the p38 MAPK inhibitory effect on Star promoter activity. Collectively, these data provide novel mechanistic information about how oxidant-sensitive p38 MAPKs, particularly p38 MAPKα, contribute to the negative regulation of Star gene expression and inhibit steroidogenesis.
Collapse
Affiliation(s)
- Syed Kashif Zaidi
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USAGeriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Wen-Jun Shen
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USAGeriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Stefanie Bittner
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Alex Bittner
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Mark P McLean
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Jiahuai Han
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Roger J Davis
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Fredric B Kraemer
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USAGeriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Salman Azhar
- Geriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USAGeriatric ResearchEducation and Clinical Center (GRECC-182B), VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, California 94304, USADivision of EndocrinologyDivision of Gastroenterology and HepatologyStanford University, Stanford, California 94305, USADepartment of Obstetrics and GynecologyUniversity of South Florida College of Medicine, Tampa, Florida 33612, USAState Key Laboratory of Cellular Stress BiologySchool of Life Sciences, Xiamen University, Xiamen, Fujian 361005, ChinaProgram in Molecular MedicineUniversity of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| |
Collapse
|
49
|
Midzak A, Papadopoulos V. Binding domain-driven intracellular trafficking of sterols for synthesis of steroid hormones, bile acids and oxysterols. Traffic 2014; 15:895-914. [PMID: 24890942 DOI: 10.1111/tra.12177] [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: 04/25/2014] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 12/16/2022]
Abstract
Steroid hormones, bioactive oxysterols and bile acids are all derived from the biological metabolism of lipid cholesterol. The enzymatic pathways generating these compounds have been an area of intense research for almost a century, as cholesterol and its metabolites have substantial impacts on human health. Owing to its high degree of hydrophobicity and the chemical properties that it confers to biological membranes, the distribution of cholesterol in cells is tightly controlled, with subcellular organelles exhibiting highly divergent levels of cholesterol. The manners in which cells maintain such sterol distributions are of great interest in the study of steroid and bile acid synthesis, as limiting cholesterol substrate to the enzymatic pathways is the principal mechanism by which production of steroids and bile acids is regulated. The mechanisms by which cholesterol moves within cells, however, remain poorly understood. In this review, we examine the subcellular machinery involved in cholesterol metabolism to steroid hormones and bile acid, relating it to both lipid- and protein-based mechanisms facilitating intracellular and intraorganellar cholesterol movement and delivery to these pathways. In particular, we examine evidence for the involvement of specific protein domains involved in cholesterol binding, which impact cholesterol movement and metabolism in steroidogenesis and bile acid synthesis. A better understanding of the physical mechanisms by which these protein- and lipid-based systems function is of fundamental importance to understanding physiological homeostasis and its perturbation.
Collapse
Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | | |
Collapse
|
50
|
Chang IY, Ohn T, Jeon YJ, Lee KH, Kim JW, Kim IY, Yoon SP. A comparison of the steroidogenic acute regulatory protein-related lipid transfer (START) domain-containing 6 on the brain and testes between young and aged rats. Acta Histochem 2014; 116:551-8. [PMID: 24360190 DOI: 10.1016/j.acthis.2013.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 11/24/2022]
Abstract
The START domain-containing 6 (StarD6) was originally reported to play a role during male germ cell maturation. We have since reported on StarD6 in the developing hypothyroid rat brain. Therefore, we investigated qualitative and quantitative changes of StarD6 in the aging rat brain and testes of male Sprague-Dawley rats. Serum testosterone levels decreased with aging and total protein levels of StarD6 in the testes decreased. While the immunolocalization of StarD6 in the spermatocytes decreased, cytoplasmic localization appeared in the aged testes. Compared with young rats, aged rats showed decreased StarD6 in the cerebrum and cerebellum without changes in immunolocalization in the cortical neurons of the cerebral cortex and Purkinje cells of the cerebellar cortex. Aged rats also showed increases in StarD6 in the hippocampus with changes in its immunolocalization from the Stratum pyramidale to the Stratum radiatum and Stratum lacunosum-moleculare. Taken together, StarD6 decreased with aging in the testes, which implies that StarD6 might play a role in impaired spermatogenesis in the aged rat. StarD6 decreased in the cerebrum and the cerebellum, but slightly increased in the hippocampus, which suggests that StarD6 might also play a role for neurosteroidogenesis in the hippocampus of aged rats.
Collapse
|