1
|
Niraula D, El Naqa I, Tuszynski JA, Gatenby RA. Modeling non-genetic information dynamics in cells using reservoir computing. iScience 2024; 27:109614. [PMID: 38632985 PMCID: PMC11022048 DOI: 10.1016/j.isci.2024.109614] [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: 01/10/2024] [Revised: 03/15/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
Virtually all cells use energy-driven, ion-specific membrane pumps to maintain large transmembrane gradients of Na+, K+, Cl-, Mg++, and Ca++, but the corresponding evolutionary benefit remains unclear. We propose that these gradients enable a dynamic and versatile biological system that acquires, analyzes, and responds to environmental information. We hypothesize that environmental signals are transmitted into the cell by ion fluxes along pre-existing gradients through gated ion-specific membrane channels. The consequent changes in cytoplasmic ion concentration can generate a local response or orchestrate global/regional cellular dynamics through wire-like ion fluxes along pre-existing and self-assembling cytoskeleton to engage the endoplasmic reticulum, mitochondria, and nucleus.
Collapse
Affiliation(s)
- Dipesh Niraula
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, USA
| | - Issam El Naqa
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, USA
| | - Jack Adam Tuszynski
- Departments of Physics and Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Data Science and Engineering, The Silesian University of Technology, 44-100 Gliwice, Poland
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin 10129, Italy
| | - Robert A. Gatenby
- Departments of Radiology and Integrated Mathematical Oncology, Moffitt Cancer Center, Tampa, FL, USA
| |
Collapse
|
2
|
Liu XH, Chen HK, Luo J, He XP, Zhang WL, Chen Y, Li XJ, Lan QW, Ma XM, Guo XG. Potassium affects the association between dietary intake of vitamin C and NAFLD among adults in the United States. PLoS One 2024; 19:e0295986. [PMID: 38635545 PMCID: PMC11025862 DOI: 10.1371/journal.pone.0295986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 12/01/2023] [Indexed: 04/20/2024] Open
Abstract
INTRODUCTION Although the association between nonalcoholic fatty liver disease (NAFLD) and vitamin C has been well studied, the effects of dietary potassium intake on this relationship are still unclear. Thus, this study aimed to determine the effects of dietary potassium intake on the association between vitamin C and NAFLD. METHODS We performed a cross-sectional learn about with 9443 contributors the usage of 2007-2018 NHANES data. Multiple logistic regression evaluation has been utilized to check out the affiliation of dietary vitamin C intake with NAFLD and advanced hepatic fibrosis (AHF). Subsequently, we plotted a smoothed match curve to visualize the association. Especially, the analysis of AHF was conducted among the NAFLD population. In addition, stratified evaluation used to be developed primarily based on demographic variables to verify the steadiness of the results. Effect amendment by way of dietary potassium intake used to be assessed via interplay checks between vitamin C and NAFLD in the multivariable linear regression. RESULTS In this cross-sectional study, we found that vitamin C was negatively related to NAFLD and AHF. The relationship between vitamin C and NAFLD was different in the low, middle and high potassium intake groups. Furthermore, potassium intake significantly modified the negative relationship between vitamin C and NAFLD in most of the models. CONCLUSION Our research showed that potassium and vitamin C have an interactive effect in reducing NAFLD, which may have great importance for clinical medication.
Collapse
Affiliation(s)
- Xu-Hua Liu
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
| | - Hao-Kai Chen
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
| | - Jing Luo
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
| | - Xiang-Ping He
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Chinese and Western Clinical Medicine, The Chinese and Western Clinical School of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Wan-Lin Zhang
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The First Clinical School of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yue Chen
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Anesthesia, The Second Clinical School of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xiu-Juan Li
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
| | - Qi-Wen Lan
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Medical Imageology, The Second Clinical School of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xiao-Man Ma
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
| | - Xu-Guang Guo
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, King Med School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| |
Collapse
|
3
|
Du X, Butler AG, Chen HY. Cell-cell interaction in the pathogenesis of inherited retinal diseases. Front Cell Dev Biol 2024; 12:1332944. [PMID: 38500685 PMCID: PMC10944940 DOI: 10.3389/fcell.2024.1332944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/06/2024] [Indexed: 03/20/2024] Open
Abstract
The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.
Collapse
Affiliation(s)
| | | | - Holly Y. Chen
- Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
4
|
Moon DO. Exploring the Role of Surface and Mitochondrial ATP-Sensitive Potassium Channels in Cancer: From Cellular Functions to Therapeutic Potentials. Int J Mol Sci 2024; 25:2129. [PMID: 38396807 PMCID: PMC10888650 DOI: 10.3390/ijms25042129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
ATP-sensitive potassium (KATP) channels are found in plasma membranes and mitochondria. These channels are a type of ion channel that is regulated by the intracellular concentration of adenosine triphosphate (ATP) and other nucleotides. In cell membranes, they play a crucial role in linking metabolic activity to electrical activity, especially in tissues like the heart and pancreas. In mitochondria, KATP channels are involved in protecting cells against ischemic damage and regulating mitochondrial function. This review delves into the role of KATP channels in cancer biology, underscoring their critical function. Notably responsive to changes in cellular metabolism, KATP channels link metabolic states to electrical activity, a feature that becomes particularly significant in cancer cells. These cells, characterized by uncontrolled growth, necessitate unique metabolic and signaling pathways, differing fundamentally from normal cells. Our review explores the intricate roles of KATP channels in influencing the metabolic and ionic balance within cancerous cells, detailing their structural and operational mechanisms. We highlight the channels' impact on cancer cell survival, proliferation, and the potential of KATP channels as therapeutic targets in oncology. This includes the challenges in targeting these channels due to their widespread presence in various tissues and the need for personalized treatment strategies. By integrating molecular biology, physiology, and pharmacology perspectives, the review aims to enhance the understanding of cancer as a complex metabolic disease and to open new research and treatment avenues by focusing on KATP channels. This comprehensive approach provides valuable insights into the potential of KATP channels in developing innovative cancer treatments.
Collapse
Affiliation(s)
- Dong-Oh Moon
- Department of Biology Education, Daegu University, 201, Daegudae-ro, Gyeongsan-si 38453, Gyeongsangbuk-do, Republic of Korea
| |
Collapse
|
5
|
Marakhova II, Yurinskaya VE, Domnina AP. The Role of Intracellular Potassium in Cell Quiescence, Proliferation, and Death. Int J Mol Sci 2024; 25:884. [PMID: 38255956 PMCID: PMC10815214 DOI: 10.3390/ijms25020884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/28/2023] [Accepted: 01/06/2024] [Indexed: 01/24/2024] Open
Abstract
This brief review explores the role of intracellular K+ during the transition of cells from quiescence to proliferation and the induction of apoptosis. We focus on the relationship between intracellular K+ and the growth and proliferation rates of different cells, including transformed cells in culture as well as human quiescent T cells and mesenchymal stem cells, and analyze the concomitant changes in K+ and water content in both proliferating and apoptotic cells. Evidence is discussed indicating that during the initiation of cell proliferation and apoptosis changes in the K+ content in cells occur in parallel with changes in water content and therefore do not lead to significant changes in the intracellular K+ concentration. We conclude that K+, as a dominant intracellular ion, is involved in the regulation of cell volume during the transit from quiescence, and the content of K+ and water in dividing cells is higher than in quiescent or differentiated cells, which can be considered to be a hallmark of cell proliferation and transformation.
Collapse
Affiliation(s)
- Irina I. Marakhova
- Department of Intracellular Signalling and Transport, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Avenue 4, 194064 Saint-Petersburg, Russia
| | - Valentina E. Yurinskaya
- Department of Molecular Cell Physiology, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Avenue 4, 194064 Saint-Petersburg, Russia
| | - Alisa P. Domnina
- Department of Intracellular Signalling and Transport, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Avenue 4, 194064 Saint-Petersburg, Russia
| |
Collapse
|
6
|
Hassan WM, Al-Dbass A, Al-Ayadhi L, Bhat RS, El-Ansary A. Discriminant analysis and binary logistic regression enable more accurate prediction of autism spectrum disorder than principal component analysis. Sci Rep 2022; 12:3764. [PMID: 35260688 PMCID: PMC8904630 DOI: 10.1038/s41598-022-07829-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction and restricted, repetitive behavior. Multiple studies have suggested mitochondrial dysfunction, glutamate excitotoxicity, and impaired detoxification mechanism as accepted etiological mechanisms of ASD that can be targeted for therapeutic intervention. In the current study, blood samples were collected from 40 people with autism and 40 control participants after informed consent and full approval from the Institutional Review Board of King Saud University. Sodium (Na+), Potassium (K+), lactate dehydrogenase (LDH), glutathione-s-transferase (GST), and mitochondrial respiratory chain complex I (MRC1) were measured in plasma of both groups. Predictive models were established to discriminate individuals with ASD from controls. The predictive power of these five variables, individually and in combination, was compared using the area under a ROC curve (AUC). We compared the performance of principal component analysis (PCA), discriminant analysis (DA), and binary logistic regression (BLR) as ways to combine single variables and create the predictive models. K+ had the highest AUC (0.801) of any single variable, followed by GST, LDH, Na+, and MRC1, respectively. Combining the five variables resulted in higher AUCs than those obtained using single variables across all models. Both DA and BLR were superior to PCA and comparable to each other. In our study, the combination of Na+, K+, LDH, GST, and MRC1 showed the highest promise in discriminating individuals with autism from controls. These results provide a platform that can potentially be used to verify the efficacy of our models with a larger sample size or evaluate other biomarkers.
Collapse
Affiliation(s)
- Wail M Hassan
- Department of Biomedical Sciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Abeer Al-Dbass
- Biochemistry Department, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Laila Al-Ayadhi
- Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.,Autism Research and Treatment Center, Riyadh, Saudi Arabia
| | - Ramesa Shafi Bhat
- Biochemistry Department, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Afaf El-Ansary
- Autism Research and Treatment Center, Riyadh, Saudi Arabia. .,Central Research Laboratory, Female Centre for Scientific and Medical Studies, King Saud University, Riyadh, Saudi Arabia.
| |
Collapse
|
7
|
Nomiri S, Hoshyar R, Chamani E, Rezaei Z, Salmani F, Larki P, Tavakoli T, Gholipour F, Tabrizi NJ, Derakhshani A, Santarpia M, Franchina T, Brunetti O, Silvestris N, Safarpour H. Prediction and validation of GUCA2B as the hub-gene in colorectal cancer based on co-expression network analysis: In-silico and in-vivo study. Biomed Pharmacother 2022; 147:112691. [PMID: 35151227 DOI: 10.1016/j.biopha.2022.112691] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Several serious attempts to treat colorectal cancer have been made in recent decades. However, no effective treatment has yet been discovered due to the complexities of its etiology. METHODS we used Weighted Gene Co-expression Network Analysis (WGCNA) to identify key modules, hub-genes, and mRNA-miRNA regulatory networks associated with CRC. Next, enrichment analysis of modules has been performed using Cluepedia. Next, quantitative real-time PCR (RT-qPCR) was used to validate the expression of selected hub-genes in CRC tissues. RESULTS Based on the WGCNA results, the brown module had a significant positive correlation (r = 0.98, p-value=9e-07) with CRC. Using the survival and DEGs analyses, 22 genes were identified as hub-genes. Next, three candidate hub-genes were selected for RT-qPCR validation, and 22 pairs of cancerous and non-cancerous tissues were collected from CRC patients referred to the Gastroenterology and Liver Clinic. The RT-qPCR results revealed that the expression of GUCA2B was significantly reduced in CRC tissues, which is consistent with the results of differential expression analysis. Finally, top miRNAs correlated with GUCA2B were identified, and ROC analyses revealed that GUCA2B has a high diagnostic performance for CRC. CONCLUSIONS The current study discovered key modules and GUCA2B as a hub-gene associated with CRC, providing references to understand the pathogenesis and be considered a novel candidate to CRC target therapy.
Collapse
Affiliation(s)
- Samira Nomiri
- Department of Clinical Biochemistry, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Reyhane Hoshyar
- Department of Clinical Biochemistry, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Elham Chamani
- Department of Clinical Biochemistry, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Zohreh Rezaei
- Department of Biology, Faculty of Sciences, University of Sistan and Balouchestan, Zahedan, Iran
| | - Fatemeh Salmani
- Department of Epidemiology and Biostatistics, Social Determinants of Health Research Center, Faculty of Health, Birjand University of Medical Sciences, Birjand, Iran
| | - Pegah Larki
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tahmine Tavakoli
- Cardiovascular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Faranak Gholipour
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Neda Jalili Tabrizi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Afshin Derakhshani
- Laboratory of Experimental Pharmacology, IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy
| | - Mariacarmela Santarpia
- Medical Oncology Unit, Department of Human Pathology "G. Barresi", University of Messina, Messina, Italy
| | - Tindara Franchina
- Medical Oncology Unit, Department of Human Pathology "G. Barresi", University of Messina, Messina, Italy
| | - Oronzo Brunetti
- Medical Oncology Unit, IRCCS Istituto Tumori "Giovanni Paolo II" of Bari, Bari, Italy
| | - Nicola Silvestris
- Medical Oncology Unit, IRCCS Istituto Tumori "Giovanni Paolo II" of Bari, Bari, Italy; Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari, Bari, Italy.
| | - Hossein Safarpour
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran.
| |
Collapse
|
8
|
Roufayel R, Younes K, Al-Sabi A, Murshid N. BH3-Only Proteins Noxa and Puma Are Key Regulators of Induced Apoptosis. Life (Basel) 2022; 12:life12020256. [PMID: 35207544 PMCID: PMC8875537 DOI: 10.3390/life12020256] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 12/29/2022] Open
Abstract
Apoptosis is an evolutionarily conserved and tightly regulated cell death pathway. Physiological cell death is important for maintaining homeostasis and optimal biological conditions by continuous elimination of undesired or superfluous cells. The BH3-only pro-apoptotic members are strong inducers of apoptosis. The pro-apoptotic BH3-only protein Noxa activates multiple death pathways by inhibiting the anti-apoptotic Bcl-2 family protein, Mcl-1, and other protein members leading to Bax and Bak activation and MOMP. On the other hand, Puma is induced by p53-dependent and p53-independent apoptotic stimuli in several cancer cell lines. Moreover, this protein is involved in several physiological and pathological processes, such as immunity, cancer, and neurodegenerative diseases. Future heat shock research could disclose the effect of hyperthermia on both Noxa and BH3-only proteins. This suggests post-transcriptional mechanisms controlling the translation of both Puma and Noxa mRNA in heat-shocked cells. This study was also the chance to recapitulate the different reactional mechanisms investigated for caspases.
Collapse
|
9
|
Joshi S, Ghosh P, Barage S, Basu B, Deobagkar DD. Genome-wide lone strand adenine methylation in Deinococcus radiodurans R1: Regulation of gene expression through DR0643-dependent adenine methylation. Microbiol Res 2022; 257:126964. [PMID: 35042054 DOI: 10.1016/j.micres.2022.126964] [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: 05/24/2021] [Revised: 12/19/2021] [Accepted: 01/11/2022] [Indexed: 10/19/2022]
Abstract
DNA methylation is a covalent modification of adenine or cytosine in the genome of an organism and is found in diverse microbes including the radiation resistant bacterium Deinococcus radiodurans R1. Although earlier findings have confirmed repression or de-repression of certain genes in adenine methyltransferase (DR_0643/Dam1DR) deficient D. radiodurans mutant however, the overall regulatory aspects of Dam1DR-mediated adenine methylation remain mostly unexplored. In the present study, we compared the genome-wide methylome and the corresponding transcriptome of D. radiodurans WT and Δdam1 mutant to explore the correlation between methylation and gene expression. In D. radiodurans, deletion of DR_0643 ORF (Δdam1) led to hypomethylation of 512 genes resulting in differential expression of 168 genes (99 genes are upregulated and 69 genes are downregulated). The modification patterns deduced for Dam1DR (DR_0643) and Dam2DR (DR_2267) were non-palindromic and atypical. Moreover, we observed methylation at opportunistic sites that show adenine methylation only in D. radiodurans Δdam1 and not in D. radiodurans WT. Correlation between the methylome and transcriptome suggests that hypomethylation at Dam1DR specific sites had both negative as well as a positive effects on gene expression. Pathways such as amino acid metabolism, transport, oxidative phosphorylation, quorum sensing, signal transduction, two-component system, glycolysis/gluconeogenesis, TCA cycle, glyoxylate and dicarboxylate metabolism were modulated by Dam1DR-mediated adenine methylation in D. radiodurans. Processes such as DNA repair, recombination, ATPase and transmembrane transporter activity were enriched when Dam1DR mutant was subjected to radiation stress. We further evaluated the molecular interactions and mode of binding between Dam1DR protein and S-adenosyl methionine using molecular docking followed by MD simulation. To get a better insight into the methylation mechanism, the Dam1DR-SAM complex was also docked with a DNA molecule to elucidate DNA-Dam1DR structural interaction during methyl-group transfer reaction. In summary, our work presents comprehensive and integrative approaches to investigate both functional and structural aspects of DNA adenine methyltransferase (Dam1DR) in D. radiodurans biology.
Collapse
Affiliation(s)
- Suraj Joshi
- Molecular Biology Research Laboratory, Department of Zoology, Savitribai Phule Pune University, Pune, India; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Bioinformatics Centre, Savitribai Phule Pune University, Pune, India
| | - Payel Ghosh
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, India.
| | - Sagar Barage
- Amity Institute of Biotechnology, Amity University, Mumbai - Pune Expressway, Bhatan, Post-Somathne, Panvel, Maharashtra, 410206, India
| | - Bhakti Basu
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Deepti D Deobagkar
- Molecular Biology Research Laboratory, Department of Zoology, Savitribai Phule Pune University, Pune, India.
| |
Collapse
|
10
|
Bustamante HA, Ehrich MF, Klein BG. Intracellular potassium depletion enhances apoptosis induced by staurosporine in cultured trigeminal satellite glial cells. Somatosens Mot Res 2021; 38:194-201. [PMID: 34187291 DOI: 10.1080/08990220.2021.1941843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Satellite glial cells (SGC) surrounding neurons in sensory ganglia can buffer extracellular potassium, regulating the excitability of injured neurons and possibly influencing a shift from acute to neuropathic pain. SGC apoptosis may be a key component in this process. This work evaluated induction or enhancement of apoptosis in cultured trigeminal SGC following changes in intracellular potassium [K]ic. MATERIALS AND METHODS We developed SGC primary cultures from rat trigeminal ganglia (TG). Purity of our cultures was confirmed using immunofluorescence and western blot analysis for the presence of the specific marker of SGC, glutamine synthetase (GS). SGC [K]ic was depleted using hypo-osmotic shock and 4 mM bumetanide plus 10 mM ouabain. [K]ic was measured using the K+ fluorescent indicator potassium benzofuran isophthalate (PBFI-AM). RESULTS SGC tested positive for GS and hypo-osmotic shock induced a significant decrease in [K]ic at every evaluated time. Cells were then incubated for 5 h with either 2 mM staurosporine (STS) or 20 ng/ml of TNF-α and evaluated for early apoptosis and late apoptosis/necrosis by flow cytometry using annexin V and propidium iodide. A significant increase in early apoptosis, from 16 to 38%, was detected in SGC with depleted [K]ic after incubation with STS. In contrast, TNF-α did not increase early apoptosis in normal or [K]ic depleted SGC. CONCLUSION Hypo-osmotic shock induced a decrease in intracellular potassium in cultured trigeminal SGC and this enhanced apoptosis induced by STS that is associated with the mitochondrial pathway. These results suggest that K+ dysregulation may underlie apoptosis in trigeminal SGC.
Collapse
Affiliation(s)
- Hedie A Bustamante
- Faculty of Veterinary Sciences, Veterinary Clinical Sciences Institute, Universidad Austral de Chile, Valdivia, Chile
| | - Marion F Ehrich
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Bradley G Klein
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| |
Collapse
|
11
|
Quo vadis Cardiac Glycoside Research? Toxins (Basel) 2021; 13:toxins13050344. [PMID: 34064873 PMCID: PMC8151307 DOI: 10.3390/toxins13050344] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 12/16/2022] Open
Abstract
Cardiac glycosides (CGs), toxins well-known for numerous human and cattle poisoning, are natural compounds, the biosynthesis of which occurs in various plants and animals as a self-protective mechanism to prevent grazing and predation. Interestingly, some insect species can take advantage of the CG’s toxicity and by absorbing them, they are also protected from predation. The mechanism of action of CG’s toxicity is inhibition of Na+/K+-ATPase (the sodium-potassium pump, NKA), which disrupts the ionic homeostasis leading to elevated Ca2+ concentration resulting in cell death. Thus, NKA serves as a molecular target for CGs (although it is not the only one) and even though CGs are toxic for humans and some animals, they can also be used as remedies for various diseases, such as cardiovascular ones, and possibly cancer. Although the anticancer mechanism of CGs has not been fully elucidated, yet, it is thought to be connected with the second role of NKA being a receptor that can induce several cell signaling cascades and even serve as a growth factor and, thus, inhibit cancer cell proliferation at low nontoxic concentrations. These growth inhibitory effects are often observed only in cancer cells, thereby, offering a possibility for CGs to be repositioned for cancer treatment serving not only as chemotherapeutic agents but also as immunogenic cell death triggers. Therefore, here, we report on CG’s chemical structures, production optimization, and biological activity with possible use in cancer therapy, as well as, discuss their antiviral potential which was discovered quite recently. Special attention has been devoted to digitoxin, digoxin, and ouabain.
Collapse
|
12
|
Sergeeva EG, Rosenberg PA, Benowitz LI. Non-Cell-Autonomous Regulation of Optic Nerve Regeneration by Amacrine Cells. Front Cell Neurosci 2021; 15:666798. [PMID: 33935656 PMCID: PMC8085350 DOI: 10.3389/fncel.2021.666798] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Visual information is conveyed from the eye to the brain through the axons of retinal ganglion cells (RGCs) that course through the optic nerve and synapse onto neurons in multiple subcortical visual relay areas. RGCs cannot regenerate their axons once they are damaged, similar to most mature neurons in the central nervous system (CNS), and soon undergo cell death. These phenomena of neurodegeneration and regenerative failure are widely viewed as being determined by cell-intrinsic mechanisms within RGCs or to be influenced by the extracellular environment, including glial or inflammatory cells. However, a new concept is emerging that the death or survival of RGCs and their ability to regenerate axons are also influenced by the complex circuitry of the retina and that the activation of a multicellular signaling cascade involving changes in inhibitory interneurons - the amacrine cells (AC) - contributes to the fate of RGCs. Here, we review our current understanding of the role that interneurons play in cell survival and axon regeneration after optic nerve injury.
Collapse
Affiliation(s)
- Elena G. Sergeeva
- Department of Neurology, Boston Children’s Hospital, Boston, MA, United States
- Kirby Center for Neuroscience, Boston Children’s Hospital, Boston, MA, United States
- Department of Neurology, Harvard Medical School, Boston, MA, United States
| | - Paul A. Rosenberg
- Department of Neurology, Boston Children’s Hospital, Boston, MA, United States
- Kirby Center for Neuroscience, Boston Children’s Hospital, Boston, MA, United States
- Department of Neurology, Harvard Medical School, Boston, MA, United States
| | - Larry I. Benowitz
- Kirby Center for Neuroscience, Boston Children’s Hospital, Boston, MA, United States
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children’s Hospital, Boston, MA, United States
- Department of Neurosurgery, Boston Children’s Hospital, Boston, MA, United States
- Department of Neurosurgery, Harvard Medical School, Boston, MA, United States
- Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
13
|
Hu S, Han R, Chen L, Qin W, Xu X, Shi J, Zhu X, Zhang M, Zeng C, Tang Z, Bao H, Liu Z. Upregulated LRRC55 promotes BK channel activation and aggravates cell injury in podocytes. J Exp Med 2021; 218:e20192373. [PMID: 33346797 PMCID: PMC7756252 DOI: 10.1084/jem.20192373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/27/2020] [Accepted: 09/16/2020] [Indexed: 12/15/2022] Open
Abstract
Podocyte injury is a common hallmark in various glomerular diseases. The level of LRRC55 was increased in podocytes of patients with focal segmental glomerulosclerosis (FSGS), diabetic nephropathy (DN), and membranous nephropathy (MN). Upregulated LRRC55 and increased intracellular Ca2+ led to BK channel activation and the loss of intracellular potassium, resulting in apoptosome formation and caspase-3 activation in angiotensin II (Ang II)-treated podocytes. Knockout of Lrrc55 or the BK channel prevented the BK current and ameliorated podocyte injury in Ang II-treated mice. Upstream, NFATc3 regulated the expression of LRRC55. Increased LRRC55 expression in podocytes was also evident in animal models of FSGS, DN, and MN. Treatment with losartan or LRRC55 siRNA suppressed LRRC55 expression, prevented BK channel activation, and attenuated podocyte injury in animal models of FSGS, DN, and MN. In conclusion, upregulated LRRC55 promotes BK channel activation and aggravates cell injury in podocytes in FSGS, DN, and MN. LRRC55 inhibition may represent a new therapeutic approach for podocyte injury.
Collapse
Affiliation(s)
- Shuai Hu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Runhong Han
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Long Chen
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Weisong Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiaodong Xu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jingsong Shi
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiaodong Zhu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Mingchao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Caihong Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zheng Tang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Hao Bao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| |
Collapse
|
14
|
Micro x-ray fluorescence analysis of trace element distribution in frozen hydrated HeLa cells at the P06 beamline at Petra III. Biointerphases 2021; 16:011004. [PMID: 33706519 DOI: 10.1116/6.0000593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
X-ray fluorescence analysis enables the study of trace element distributions in biological specimens. When this analysis is done under cryogenic conditions, cells are cryofixed as closely as possible to their natural physiological state, and the corresponding intracellular elemental densities can be analyzed. Details about the experimental setup used for analysis at the P06 beamline at Petra III, DESY and the used cryo-transfer system are described in this work. The system was applied to analyze the elemental distribution in single HeLa cells, a cell line frequently used in a wide range of biological applications. Cells adhered to silicon nitride substrates were cryoprotected within an amorphous ice matrix. Using a continuous scanning scheme and a KB x-ray focus, the distribution of elements in the cells was studied. We were able to image the intracellular potassium and zinc levels in HeLa cells as two key elements relevant for the physiology of cells.
Collapse
|
15
|
Planeta K, Setkowicz Z, Janik-Olchawa N, Matusiak K, Ryszawy D, Drozdz A, Janeczko K, Ostachowicz B, Chwiej J. Comparison of Elemental Anomalies Following Implantation of Different Cell Lines of Glioblastoma Multiforme in the Rat Brain: A Total Reflection X-ray Fluorescence Spectroscopy Study. ACS Chem Neurosci 2020; 11:4447-4459. [PMID: 33205959 PMCID: PMC7747222 DOI: 10.1021/acschemneuro.0c00648] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/09/2020] [Indexed: 12/20/2022] Open
Abstract
Glioblastoma multiforme (GBM) is a primary brain tumor with a very high degree of malignancy and is classified by WHO as a glioma IV. At present, the treatment of patients suffering from GBM is based on surgical resection of the tumor with maximal protection of surrounding tissues followed by radio- and pharmacological therapy using temozolomide as the most frequently recommended drug. This strategy, however, does not guarantee success and has devastating consequences. Testing of new substances or therapies having potential in the treatment of GBM as well as detection of their side effects cannot be done on humans. Animal models of the disease are usually used for these purposes, and one possibility is the implantation of human tumor cells into rodent brains. Such a solution was used in the present study the purpose of which was comparison of elemental anomalies appearing in the brain as a result of implantation of different glioblastoma cell lines. These were two commercially available cell lines (U87MG and T98G), as well as tumor cells taken directly from a patient diagnosed with GBM. Using total reflection X-ray fluorescence we determined the contents of P, S, K, Ca, Fe, Cu, Zn, and Se in implanted-left and intact-right brain hemispheres. The number of elemental anomalies registered for both hemispheres was positively correlated with the invasiveness of GBM cells and was the highest for animals subjected to U87MG cell implantation, which presented significant decrease of P, K, and Cu levels and an increase of Se concentration within the left hemisphere. The abnormality common for all three groups of animals subjected to glioma cell implantation was increased Fe level in the brain, which may result from higher blood supply or the presence of hemorrhaging regions. In the case of the intact hemisphere, elevated Fe concentration may also indicate higher neuronal activity caused by taking over some functions of the left hemisphere impaired as a result of tumor growth.
Collapse
Affiliation(s)
- Karolina Planeta
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| | - Zuzanna Setkowicz
- Jagiellonian
University, Institute of Zoology
and Biomedical Research, Krakow 31-007, Poland
| | - Natalia Janik-Olchawa
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| | - Katarzyna Matusiak
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| | - Damian Ryszawy
- Jagiellonian
University, Faculty of Biochemistry,
Biophysics, and Biotechnology, Krakow 31-007, Poland
| | - Agnieszka Drozdz
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| | - Krzysztof Janeczko
- Jagiellonian
University, Institute of Zoology
and Biomedical Research, Krakow 31-007, Poland
| | - Beata Ostachowicz
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| | - Joanna Chwiej
- AGH
University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow 30-059, Poland
| |
Collapse
|
16
|
Luo L, Wang J, Ding D, Hasan MN, Yang SS, Lin SH, Schreppel P, Sun B, Yin Y, Erker T, Sun D. Role of NKCC1 Activity in Glioma K + Homeostasis and Cell Growth: New Insights With the Bumetanide-Derivative STS66. Front Physiol 2020; 11:911. [PMID: 32848856 PMCID: PMC7413028 DOI: 10.3389/fphys.2020.00911] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/08/2020] [Indexed: 12/01/2022] Open
Abstract
Introduction: Na+-K+-2Cl− cotransporter isoform 1 (NKCC1) is important in regulating intracellular K+ and Cl− homeostasis and cell volume. In this study, we investigated a role of NKCC1 in regulating glioma K+ influx and proliferation in response to apoptosis inducing chemotherapeutic drug temozolomide (TMZ). The efficacy of a new bumetanide (BMT)-derivative NKCC1 inhibitor STS66 [3-(butylamino)-2-phenoxy-5-[(2, 2, 2-trifluoroethylamino) methyl] benzenesulfonamide] in blocking NKCC1 activity was compared with well-established NKCC1 inhibitor BMT. Methods: NKCC1 activity in cultured mouse GL26 and SB28-GFP glioma cells was measured by Rb+ (K+) influx. The WNK1-SPAK/OSR1-NKCC1 signaling and AKT/ERK-mTOR signaling protein expression and activation were assessed by immunoblotting. Cell growth was determined by bromodeoxyuridine (BrdU) incorporation assay, MTT proliferation assay, and cell cycle analysis. Impact of STS66 and BMT on cell Rb+ influx and growth was measured in glioma cells treated with or without TMZ. Results: Rb+ influx assay showed that 10 μM BMT markedly decreased the total Rb+ influx and no additional inhibition detected at >10 μM BMT. In contrast, the maximum effects of STS66 on Rb+ influx inhibition were at 40–60 μM. Both BMT and STS66 reduced TMZ-mediated NKCC1 activation and protein upregulation. Glioma cell growth can be reduced by STS66. The most robust inhibition of glioma growth, cell cycle, and AKT/ERK signaling was achieved by the TMZ + STS66 treatment. Conclusion: The new BMT-derivative NKCC1 inhibitor STS66 is more effective than BMT in reducing glioma cell growth in part by inhibiting NKCC1-mediated K+ influx. TMZ + STS66 combination treatment reduces glioma cell growth via inhibiting cell cycle and AKT-ERK signaling.
Collapse
Affiliation(s)
- Lanxin Luo
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States
| | - Jun Wang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, China
| | - Dawei Ding
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States
| | - Md Nabiul Hasan
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sung-Sen Yang
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Philipp Schreppel
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Baoshan Sun
- Pólo Dois Portos, Instituto National de Investigação Agrária e Veterinária, I.P., Quinta da Almoinha, Dois Portos, Portugal
| | - Yan Yin
- Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, China
| | - Thomas Erker
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, United States
| |
Collapse
|
17
|
Aizenman E, Loring RH, Reynolds IJ, Rosenberg PA. The Redox Biology of Excitotoxic Processes: The NMDA Receptor, TOPA Quinone, and the Oxidative Liberation of Intracellular Zinc. Front Neurosci 2020; 14:778. [PMID: 32792905 PMCID: PMC7393236 DOI: 10.3389/fnins.2020.00778] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/02/2020] [Indexed: 12/14/2022] Open
Abstract
This special issue of Frontiers in Neuroscience-Neurodegeneration celebrates the 50th anniversary of John Olney's seminal work introducing the concept of excitotoxicity as a mechanism for neuronal cell death. Since that time, fundamental research on the pathophysiological activation of glutamate receptors has played a central role in our understanding of excitotoxic cellular signaling pathways, leading to the discovery of many potential therapeutic targets in the treatment of acute or chronic/progressive neurodegenerative disorders. Importantly, excitotoxic signaling processes have been found repeatedly to be closely intertwined with oxidative cellular cascades. With this in mind, this review looks back at long-standing collaborative efforts by the authors linking cellular redox status and glutamate neurotoxicity, focusing first on the discovery of the redox modulatory site of the N-methyl-D-aspartate (NMDA) receptor, followed by the study of the oxidative conversion of 3,4-dihydroxyphenylalanine (DOPA) to the non-NMDA receptor agonist and neurotoxin 2,4,5-trihydroxyphenylalanine (TOPA) quinone. Finally, we summarize our work linking oxidative injury to the liberation of zinc from intracellular metal binding proteins, leading to the uncovering of a signaling mechanism connecting excitotoxicity with zinc-activated cell death-signaling cascades.
Collapse
Affiliation(s)
- Elias Aizenman
- Department of Neurobiology, Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ralph H. Loring
- Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, Boston, MA, United States
| | | | - Paul A. Rosenberg
- Program in Neuroscience, F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
18
|
Chow LWC, Leung YM. The versatile Kv channels in the nervous system: actions beyond action potentials. Cell Mol Life Sci 2020; 77:2473-2482. [PMID: 31894358 PMCID: PMC11104815 DOI: 10.1007/s00018-019-03415-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/16/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022]
Abstract
Voltage-gated K+ (Kv) channel opening repolarizes excitable cells by allowing K+ efflux. Over the last two decades, multiple Kv functions in the nervous system have been found to be unrelated to or beyond the immediate control of excitability, such as shaping action potential contours or regulation of inter-spike frequency. These functions include neuronal exocytosis and neurite formation, neuronal cell death, regulation of astrocyte Ca2+, glial cell and glioma proliferation. Some of these functions have been shown to be independent of K+ conduction, that is, they suggest the non-canonical functions of Kv channels. In this review, we focus on neuronal or glial plasmalemmal Kv channel functions which are unrelated to shaping action potentials or immediate control of excitability. Similar functions in other cell types will be discussed to some extent in appropriate contexts.
Collapse
Affiliation(s)
- Louis W C Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
- UNIMED Medical Institute, Hong Kong, China
- Organisation for Oncology and Translational Research, Hong Kong, China
| | - Yuk- Man Leung
- Department of Physiology, China Medical University, Taichung, 40402, Taiwan.
| |
Collapse
|
19
|
Scorpion Toxins and Ion Channels: Potential Applications in Cancer Therapy. Toxins (Basel) 2020; 12:toxins12050326. [PMID: 32429050 PMCID: PMC7290751 DOI: 10.3390/toxins12050326] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/24/2022] Open
Abstract
Apoptosis, a genetically directed process of cell death, has been studied for many years, and the biochemical mechanisms that surround it are well known and described. There are at least three pathways by which apoptosis occurs, and each pathway depends on extra or intracellular processes for activation. Apoptosis is a vital process, but disturbances in proliferation and cell death rates can lead to the development of diseases like cancer. Several compounds, isolated from scorpion venoms, exhibit inhibitory effects on different cancer cells. Indeed, some of these compounds can differentiate between healthy and cancer cells within the same tissue. During the carcinogenic process, morphological, biochemical, and biological changes occur that enable these compounds to modulate cancer but not healthy cells. This review highlights cancer cell features that enable modulation by scorpion neurotoxins. The properties of the isolated scorpion neurotoxins in cancer cells and the potential uses of these compounds as alternative treatments for cancer are discussed.
Collapse
|
20
|
Cytosolic Acidification Is the First Transduction Signal of Lactoferrin-induced Regulated Cell Death Pathway. Int J Mol Sci 2019; 20:ijms20235838. [PMID: 31757076 PMCID: PMC6928705 DOI: 10.3390/ijms20235838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 01/04/2023] Open
Abstract
In yeast, we reported the critical role of K+-efflux for the progress of the regulated cell death (RCD) induced by human lactoferrin (hLf), an antimicrobial protein of the innate immune system that blocks Pma1p H+-ATPase. In the present study, the K+ channel Tok1p was identified as the K+ channel-mediating K+-efflux, as indicated by the protective effect of extracellular K+ (30 mM), K+-channel blockers, and the greater hLf-resistance of TOK1-disrupted strains. K+-depletion was necessary but not sufficient to induce RCD as inferred from the effects of valinomycin, NH4Cl or nigericin which released a percentage of K+ similar to that released by lactoferrin without affecting cell viability. Cytosolic pH of hLf-treated cells decreased transiently (0.3 pH units) and its inhibition prevented the RCD process, indicating that cytosolic acidification was a necessary and sufficient triggering signal. The blocking effect of lactoferrin on Pma1p H+-ATPase caused a transitory decrease of cytosolic pH, and the subsequent membrane depolarization activated the voltage-gated K+ channel, Tok1p, allowing an electrogenic K+-efflux. These ionic events, cytosolic accumulation of H+ followed by K+-efflux, constituted the initiating signals of this mitochondria-mediated cell death. These findings suggest, for the first time, the existence of an ionic signaling pathway in RCD.
Collapse
|
21
|
Live cell imaging of signaling and metabolic activities. Pharmacol Ther 2019; 202:98-119. [DOI: 10.1016/j.pharmthera.2019.06.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/31/2019] [Indexed: 12/15/2022]
|
22
|
Wang W, Ma Y, He J, Qi H, Xiao F, He S. Gene regulation for the extreme resistance to ionizing radiation of Deinococcus radiodurans. Gene 2019; 715:144008. [DOI: 10.1016/j.gene.2019.144008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/24/2019] [Accepted: 07/24/2019] [Indexed: 01/05/2023]
|
23
|
Yeh CY, Ye Z, Moutal A, Gaur S, Henton AM, Kouvaros S, Saloman JL, Hartnett-Scott KA, Tzounopoulos T, Khanna R, Aizenman E, Camacho CJ. Defining the Kv2.1-syntaxin molecular interaction identifies a first-in-class small molecule neuroprotectant. Proc Natl Acad Sci U S A 2019; 116:15696-15705. [PMID: 31308225 PMCID: PMC6681760 DOI: 10.1073/pnas.1903401116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The neuronal cell death-promoting loss of cytoplasmic K+ following injury is mediated by an increase in Kv2.1 potassium channels in the plasma membrane. This phenomenon relies on Kv2.1 binding to syntaxin 1A via 9 amino acids within the channel intrinsically disordered C terminus. Preventing this interaction with a cell and blood-brain barrier-permeant peptide is neuroprotective in an in vivo stroke model. Here a rational approach was applied to define the key molecular interactions between syntaxin and Kv2.1, some of which are shared with mammalian uncoordinated-18 (munc18). Armed with this information, we found a small molecule Kv2.1-syntaxin-binding inhibitor (cpd5) that improves cortical neuron survival by suppressing SNARE-dependent enhancement of Kv2.1-mediated currents following excitotoxic injury. We validated that cpd5 selectively displaces Kv2.1-syntaxin-binding peptides from syntaxin and, at higher concentrations, munc18, but without affecting either synaptic or neuronal intrinsic properties in brain tissue slices at neuroprotective concentrations. Collectively, our findings provide insight into the role of syntaxin in neuronal cell death and validate an important target for neuroprotection.
Collapse
Affiliation(s)
- Chung-Yang Yeh
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Zhaofeng Ye
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- School of Medicine, Tsinghua University, Beijing 100871, China
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724
| | - Shivani Gaur
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Amanda M Henton
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Stylianos Kouvaros
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jami L Saloman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Karen A Hartnett-Scott
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Thanos Tzounopoulos
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261;
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Carlos J Camacho
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261;
| |
Collapse
|
24
|
Tan XF, Qin T, Li N, Yang YG, Zheng JH, Xie L, Chen MH. High-potassium preconditioning enhances tolerance to focal cerebral ischemia-reperfusion injury through anti-apoptotic effects in male rats. J Neurosci Res 2019; 97:1253-1265. [PMID: 31240758 DOI: 10.1002/jnr.24483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/16/2019] [Accepted: 05/30/2019] [Indexed: 11/07/2022]
Abstract
Imbalances between cellular K+ efflux and influx are considered to be involved in cerebral ischemia-reperfusion (I/R) injury. High-potassium pretreatment alleviates this injury, but the underlying molecular mechanism is unclear. In this study, we sought to investigate whether high-potassium preconditioning enhances cerebral tolerance to I/R injury through an anti-apoptotic mechanism. Adult male Sprague-Dawley rats were randomly divided into four groups (n = 40/group): a sham-operated group, normal saline group (3.2 ml/kg saline, intravenous (IV)), and low-dose and high-dose potassium chloride (KCl) groups (40 and 80 mg/kg KCl solution, IV, respectively). Subsequently, the rats underwent 90 min of middle cerebral artery occlusion (MCAO) followed by 24 hr of reperfusion (MCAO/R). Neurological deficit scores, 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin and eosin staining, and TUNEL assay were used to assess neural injury. The expression of apoptotic proteins, brain potassium levels, mitochondrial function and oxidative stress were detected to explore the potential mechanism. After 24 hr of reperfusion, in both KCl treatment groups, neurological deficits and the cerebral infarct volume were reduced, and the apoptosis index of neurons was decreased. Furthermore, high-potassium preconditioning increased brain K+ , adenosine triphosphate (ATP), cytochrome c oxidase (COX) levels, reduced malondialdehyde level, improved Na+ /K+ -ATPase, succinic dehydrogenase and superoxide dismutase activities, upregulated anti-apoptotic protein expression, and downregulated pro-apoptotic protein expression. This study suggests that high-potassium preconditioning enhanced cerebral tolerance to I/R injury in a rat MCAO/R model. The protective mechanism may involve apoptosis inhibition via preservation of intracellular K+ and improvement of mitochondrial function.
Collapse
Affiliation(s)
- Xiao-Feng Tan
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Tao Qin
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Nuo Li
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Ye-Gui Yang
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jun-Hui Zheng
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Lu Xie
- The Department of Physiology, School of Pre-Clinical Science, Guangxi Medical University, Nanning, China
| | - Meng-Hua Chen
- The Intensive Care Unit, the Second Affiliated Hospital of Guangxi Medical University, Nanning, China
| |
Collapse
|
25
|
|
26
|
|
27
|
Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells. Sci Rep 2018; 8:17818. [PMID: 30546044 PMCID: PMC6292909 DOI: 10.1038/s41598-018-36127-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/09/2018] [Indexed: 01/29/2023] Open
Abstract
In mammalian cells cytoplasm ion concentrations and hence cytoplasm conductivity is an important indicator of their physiological state. Changes in the cytoplasm conductivity has been associated with physiological changes such as progression of cancer and apoptosis. In this work, a model that predicts the effects of physiological changes in ion transport on the cytoplasm conductivity of Chinese hamster ovary (CHO) cells is demonstrated. We determined CHO-specific model parameters, Na+/K+ ATPase pumps and ion channels densities, using a flux assay approach. The obtained sodium (PNa), potassium (PK) and chloride (PCl) permeability and Na+/K+ ATPase pump density were estimated to be 5.6 × 10-8 cm/s, 5.6 × 10-8 cm/s, 3.2 × 10-7 cm/s and 2.56 × 10-11 mol/cm2, respectively. The model was tested by comparing the model predictions with the experimentally determined temporal changes in the cytoplasm conductivity of Na+/K+ ATPase pump inhibited CHO cells. Cells' Na+/K+ ATPase pumps were inhibited using 5 mM Ouabain and the temporal behavior of their cytoplasm conductivity was measured using dielectrophoresis cytometry. The measured results are in close agreement with the model-calculated values. This model will provide insight on the effects of processes such as apoptosis or external media ion concentration on the cytoplasm conductivity of mammalian cells.
Collapse
|
28
|
da Fonseca CAR, Paltian J, Dos Reis AS, Bortolatto CF, Wilhelm EA, Luchese C. Na +/K +-ATPase, acetylcholinesterase and glutathione S-transferase activities as new markers of postmortem interval in Swiss mice. Leg Med (Tokyo) 2018; 36:67-72. [PMID: 30415194 DOI: 10.1016/j.legalmed.2018.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/12/2018] [Accepted: 11/02/2018] [Indexed: 12/20/2022]
Abstract
Determining precisely the postmortem interval (PMI) is a key parameter for forensic researches, given that various physical, biochemical and metabolic changes begin to occur in the body after death. In the present study, the Na+/K+-ATPase, glutathione S-transferase (GST) and acetylcholinesterase (AChE) activities were evaluated. For this, male adult Swiss mice were killed by isoflurane inhalation anesthesia and divided into four groups according to time of death (0, 6, 24 and 48 h). The brain, liver, kidney and skeletal muscle tissues were removed. Our results revealed that at the time of 6 h, there was a decrease on Na+/K+-ATPase and GST activities in the brain and liver tissues, respectively. In addition, at this time point, an increase on renal GST activity was verified. At the time of 24 h, an increase on the cerebral AChE and renal GST activities was observed, while the cerebral Na+/K+-ATPase activity was decreased. Forty-eight hours after death, cerebral Na+/K+-ATPase and renal GST activities remained decreased and increased, respectively. In addition, no alteration was observed on the GST activity in the skeletal muscle and brain (in PMIs evaluated). The present study revealed that the brain and kidney (at the times of 24 and 48 h) were the tissues that suffered the most changes in almost all the enzymes evaluated. Our results demonstrated that enzyme activity assessments are reliable, easy-to-perform and low-cost determinations, and could be promising postmortem markers.
Collapse
Affiliation(s)
- Caren A R da Fonseca
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil; Curso de Bacharelado em Química Forense, Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil
| | - Jaini Paltian
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil; Curso de Bacharelado em Química Forense, Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil
| | - Angélica S Dos Reis
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil
| | - Cristiani F Bortolatto
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil
| | - Ethel A Wilhelm
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil; Curso de Bacharelado em Química Forense, Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil.
| | - Cristiane Luchese
- Programa de Pós-graduação em Bioquímica e Bioprospecção, Laboratório de Pesquisa em Farmacologia Bioquímica (LaFarBio), Grupo de Pesquisa em Neurobiotecnologia (GPN), Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), CEP 96010-900 Pelotas, RS, Brazil.
| |
Collapse
|
29
|
Justice JA, Manjooran DT, Yeh CY, Hartnett-Scott KA, Schulien AJ, Kosobucki GJ, Mammen S, Palladino MJ, Aizenman E. Molecular Neuroprotection Induced by Zinc-Dependent Expression of Hepatitis C-Derived Protein NS5A Targeting Kv2.1 Potassium Channels. J Pharmacol Exp Ther 2018; 367:348-355. [PMID: 30190339 PMCID: PMC6193254 DOI: 10.1124/jpet.118.252338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/06/2018] [Indexed: 12/20/2022] Open
Abstract
We present the design of an innovative molecular neuroprotective strategy and provide proof-of-concept for its implementation, relying on the injury-mediated activation of an ectopic gene construct. As oxidative injury leads to the intracellular liberation of zinc, we hypothesize that tapping onto the zinc-activated metal regulatory element (MRE) transcription factor 1 system to drive expression of the Kv2.1-targeted hepatitis C protein NS5A (hepatitis C nonstructural protein 5A) will provide neuroprotection by preventing cell death-enabling cellular potassium loss in rat cortical neurons in vitro. Indeed, using biochemical and morphologic assays, we demonstrate rapid expression of MRE-driven products in neurons. Further, we report that MRE-driven NS5A expression, induced by a slowly evolving excitotoxic stimulus, functionally blocks injurious, enhanced Kv2.1 potassium whole-cell currents and improves neuronal viability. We suggest this form of "on-demand" neuroprotection could provide the basis for a tenable therapeutic strategy to prevent neuronal cell death in neurodegeneration.
Collapse
Affiliation(s)
- Jason A Justice
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Daniel T Manjooran
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Chung-Yang Yeh
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Karen A Hartnett-Scott
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Anthony J Schulien
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gabrielle J Kosobucki
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Shalom Mammen
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Michael J Palladino
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Elias Aizenman
- Departments of Neurobiology (J.A.J., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., E.A.) and Pharmacology and Chemical Biology (D.T.M., M.J.P.) and Pittsburgh Institute for Neurodegenerative Diseases (J.A.J., D.T.M., C.-Y.Y., K.A.H.-S., A.J.S., G.J.K., S.M., M.J.P., E.A.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| |
Collapse
|
30
|
Landry DA, Rossi-Perazza L, Lafontaine S, Sirard MA. Expression of atresia biomarkers in granulosa cells after ovarian stimulation in heifers. Reproduction 2018; 156:239-248. [DOI: 10.1530/rep-18-0186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/15/2018] [Indexed: 11/08/2022]
Abstract
The use of younger gamete donors in dairy cattle genetic selection programs significantly accelerates genetic gains by decreasing the interval between generations. Ovarian stimulation (OS) and the practice of follicle-stimulating hormone (FSH) withdrawal, also known as coasting, are intensively used in pre-pubertal heifers without detrimental effects on subsequent reproductive performance but generally with lower embryo yields. However, recent data from embryo transfer programs showed similar embryo yields in younger and sexually mature animals but with a significant difference in the coasting period. The aim of the present study was to identify a set of granulosa cell biomarkers capable of distinguishing optimal follicle differentiation from late differentiation and atresia in order to assess the differences in coasting dynamics between pre- and post-pubertal donors. We integrated transcriptomic data sets from a public depository and used vote counting meta-analysis in order to elucidate the molecular changes occurring in granulosa cells during late follicle differentiation and atresia. The meta-analysis revealed the gene expression associated with follicle demise, and most importantly, identified potential biomarkers of that status in bovine granulosa cells. The comparison of the expression of six biomarkers between pre- and post-pubertal donors revealed that younger donors had more signs of atresia after the same period of coasting. We found different follicular dynamics following coasting in younger donors. It is possible that younger donors are less capable to sustain follicular survival most likely due to insufficient luteinizing hormone signaling. In summary, the pre-pubertal status influences follicular dynamics and reduces the oocyte developmental competence curve following OS and FSH withdrawal in heifers.
Collapse
|
31
|
Chow LW, Cheng KS, Wong KL, Leung YM. Voltage-gated K + channels promote BT-474 breast cancer cell migration. Chin J Cancer Res 2018; 30:613-622. [PMID: 30700930 PMCID: PMC6328511 DOI: 10.21147/j.issn.1000-9604.2018.06.06] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Objective A variety of ion channels have been implicated in breast cancer proliferation and metastasis. Voltage-gated K+ (Kv) channels not only cause repolarization in excitable cells, but are also involved in multiple cellular functions in non-excitable cells. In this study we investigated the role of Kv channels in migration of BT474 breast cancer cells. Methods Transwell technique was used to separate migratory cells from non-migratory ones and these two groups of cells were subject to electrophysiological examinations and microfluorimetric measurements for cytosolic Ca2+. Cell migration was examined in the absence or presence of Kv channel blockers. Results When compared with non-migratory cells, migratory cells had much higher Kv current densities, but rather unexpectedly, more depolarized membrane potential and reduced Ca2+ influx. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed the presence of Kv1.1, Kv1.3, Kv1.5, Kv2.1, Kv3.3, Kv3.4 and Kv4.3 channels. Cell migration was markedly inhibited by tetraethylammonium (TEA), a delayed rectifier Kv channel blocker, but not by 4-aminopyridine, an A-type Kv channel blocker. Conclusions Taken together, our results show that increased Kv channel expression played a role in BT474 cell migration, and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer metastasis. The mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Ca2+ influx.
Collapse
Affiliation(s)
- Louis Wc Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, Macau 999078, China.,UNIMED Medical Institute, Hong Kong 999077, China.,Organisation for Oncology and Translational Research, Hong Kong 999077, China
| | - Ka-Shun Cheng
- Department of Anesthesiology, China Medical University Hospital, Taichung 40447, Taiwan, China.,Department of Anesthesiology, the Qingdao University Yuhuangding Hospital, Yantai 264000, China
| | - Kar-Lok Wong
- Department of Anesthesiology, China Medical University Hospital, Taichung 40447, Taiwan, China
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung 40402, Taiwan, China
| |
Collapse
|
32
|
Dani P, Ujaoney AK, Apte SK, Basu B. Regulation of potassium dependent ATPase (kdp) operon of Deinococcus radiodurans. PLoS One 2017; 12:e0188998. [PMID: 29206865 PMCID: PMC5716572 DOI: 10.1371/journal.pone.0188998] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/16/2017] [Indexed: 11/19/2022] Open
Abstract
The genome of D. radiodurans harbors genes for structural and regulatory proteins of Kdp ATPase, in an operon pattern, on Mega plasmid 1. Organization of its two-component regulatory genes is unique. Here we demonstrate that both, the structural as well as regulatory components of the kdp operon of D. radiodurans are expressed quickly as the cells experience potassium limitation but are not expressed upon increase in osmolarity. The cognate DNA binding response regulator (RR) effects the expression of kdp operon during potassium deficiency through specific interaction with the kdp promoter. Deletion of the gene encoding RR protein renders the mutant D. radiodurans (ΔRR) unable to express kdp operon under potassium limitation. The ΔRR D. radiodurans displays no growth defect when grown on rich media or when exposed to oxidative or heat stress but shows reduced growth following gamma irradiation. The study elucidates the functional and regulatory aspects of the novel kdp operon of this extremophile, for the first time.
Collapse
Affiliation(s)
- Pratiksha Dani
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Aman Kumar Ujaoney
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - Shree Kumar Apte
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - Bhakti Basu
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
- * E-mail:
| |
Collapse
|
33
|
Adem GD, Roy SJ, Huang Y, Chen ZH, Wang F, Zhou M, Bowman JP, Holford P, Shabala S. Expressing Arabidopsis thaliana V-ATPase subunit C in barley (Hordeum vulgare) improves plant performance under saline condition by enabling better osmotic adjustment. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:1147-1159. [PMID: 32480640 DOI: 10.1071/fp17133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/28/2017] [Indexed: 06/11/2023]
Abstract
Salinity is a global problem affecting agriculture that results in an estimated US$27 billion loss in revenue per year. Overexpression of vacuolar ATPase subunits has been shown to be beneficial in improving plant performance under saline conditions. Most studies, however, have not shown whether overexpression of genes encoding ATPase subunits results in improvements in grain yield, and have not investigated the physiological mechanisms behind the improvement in plant growth. In this study, we constitutively expressed Arabidopsis Vacuolar ATPase subunit C (AtVHA-C) in barley. Transgenic plants were assessed for agronomical and physiological characteristics, such as fresh and dry biomass, leaf pigment content, stomatal conductance, grain yield, and leaf Na+ and K+ concentration, when grown in either 0 or 300mM NaCl. When compared with non-transformed barley, AtVHA-C expressing barley lines had a smaller reduction in both biomass and grain yield under salinity stress. The transgenic lines accumulated Na+ and K+ in leaves for osmotic adjustment. This in turn saves energy consumed in the synthesis of organic osmolytes that otherwise would be needed for osmotic adjustment.
Collapse
Affiliation(s)
- Getnet D Adem
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia
| | - Stuart J Roy
- Australian Centre for Plant Functional Genomics, Private Mail Bag 1, Glen Osmond, SA 5064, Australia
| | - Yuqing Huang
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Zhong-Hua Chen
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Feifei Wang
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia
| | - Meixue Zhou
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia
| | - John P Bowman
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia
| | - Paul Holford
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Sergey Shabala
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia
| |
Collapse
|
34
|
Targeting a Potassium Channel/Syntaxin Interaction Ameliorates Cell Death in Ischemic Stroke. J Neurosci 2017; 37:5648-5658. [PMID: 28483976 DOI: 10.1523/jneurosci.3811-16.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/25/2017] [Accepted: 05/01/2017] [Indexed: 12/12/2022] Open
Abstract
The voltage-gated K+ channel Kv2.1 has been intimately linked with neuronal apoptosis. After ischemic, oxidative, or inflammatory insults, Kv2.1 mediates a pronounced, delayed enhancement of K+ efflux, generating an optimal intracellular environment for caspase and nuclease activity, key components of programmed cell death. This apoptosis-enabling mechanism is initiated via Zn2+-dependent dual phosphorylation of Kv2.1, increasing the interaction between the channel's intracellular C-terminus domain and the SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor) protein syntaxin 1A. Subsequently, an upregulation of de novo channel insertion into the plasma membrane leads to the critical enhancement of K+ efflux in damaged neurons. Here, we investigated whether a strategy designed to interfere with the cell death-facilitating properties of Kv2.1, specifically its interaction with syntaxin 1A, could lead to neuroprotection following ischemic injury in vivo The minimal syntaxin 1A-binding sequence of Kv2.1 C terminus (C1aB) was first identified via a far-Western peptide screen and used to create a protherapeutic product by conjugating C1aB to a cell-penetrating domain. The resulting peptide (TAT-C1aB) suppressed enhanced whole-cell K+ currents produced by a mutated form of Kv2.1 mimicking apoptosis in a mammalian expression system, and protected cortical neurons from slow excitotoxic injury in vitro, without influencing NMDA-induced intracellular calcium responses. Importantly, intraperitoneal administration of TAT-C1aB in mice following transient middle cerebral artery occlusion significantly reduced ischemic stroke damage and improved neurological outcome. These results provide strong evidence that targeting the proapoptotic function of Kv2.1 is an effective and highly promising neuroprotective strategy.SIGNIFICANCE STATEMENT Kv2.1 is a critical regulator of apoptosis in central neurons. It has not been determined, however, whether the cell death-enabling function of this K+ channel can be selectively targeted to improve neuronal survival following injury in vivo The experiments presented here demonstrate that the cell death-specific role of Kv2.1 can be uniquely modulated to provide neuroprotection in an animal model of acute ischemic stroke. We thus reveal a novel therapeutic strategy for neurological disorders that are accompanied by Kv2.1-facilitated forms of cell death.
Collapse
|
35
|
Justice JA, Schulien AJ, He K, Hartnett KA, Aizenman E, Shah NH. Disruption of K V2.1 somato-dendritic clusters prevents the apoptogenic increase of potassium currents. Neuroscience 2017; 354:158-167. [PMID: 28461216 DOI: 10.1016/j.neuroscience.2017.04.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/01/2017] [Accepted: 04/21/2017] [Indexed: 12/27/2022]
Abstract
As the predominant mediator of the delayed rectifier current, KV2.1 is an important regulator of neuronal excitability. KV2.1, however, also plays a well-established role in apoptotic cell death. Apoptogenic stimuli induce syntaxin-dependent trafficking of KV2.1, resulting in an augmented delayed rectifier current that acts as a conduit for K+ efflux required for pro-apoptotic protease/nuclease activation. Recent evidence suggests that KV2.1 somato-dendritic clusters regulate the formation of endoplasmic reticulum-plasma membrane junctions that function as scaffolding sites for plasma membrane trafficking of ion channels, including KV2.1. However, it is unknown whether KV2.1 somato-dendritic clusters are required for apoptogenic trafficking of KV2.1. By overexpression of a protein derived from the C-terminus of the cognate channel KV2.2 (KV2.2CT), we induced calcineurin-independent disruption of KV2.1 somato-dendritic clusters in rat cortical neurons, without altering the electrophysiological properties of the channel. We observed that KV2.2CT-expressing neurons are less susceptible to oxidative stress-induced cell death. Critically, expression of KV2.2CT effectively blocked the increased current density of the delayed rectifier current associated with oxidative injury, supporting a vital role of KV2.1-somato-dendritic clusters in apoptogenic increases in KV2.1-mediated currents.
Collapse
Affiliation(s)
- Jason A Justice
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
| | - Anthony J Schulien
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Kai He
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Karen A Hartnett
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Elias Aizenman
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Niyathi H Shah
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| |
Collapse
|
36
|
Mulhall HJ, Cardnell A, Hoettges KF, Labeed FH, Hughes MP. Apoptosis progression studied using parallel dielectrophoresis electrophysiological analysis and flow cytometry. Integr Biol (Camb) 2016; 7:1396-401. [PMID: 26235126 DOI: 10.1039/c5ib00109a] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Apoptosis is characterised by many cellular events, but the standard Annexin-V assay identifies two; the transfer of the phospholipid phosphatidylserine (PS) from inner to outer leaflets of the plasma membrane, acting as an "eat me" signal to macrophages, and the permeabilisation of the plasma membrane. In this paper we compare the results from the Annexin-V assay with electrophysiology data obtained in parallel using dielectrophoresis, which highlights two changes in cell electrophysiology; a change in cytoplasmic conductivity which correlates with PS expression, and a membrane conductance spike that correlates with permeabilisation. Combining results from both methods shows a strong inverse relationship between conductivity and PS externalisation. One mechanism which may explain this correlation is related to intracellular Ca(2+), which is known to increase early in apoptosis. PS expression occurs when enzymes called scramblases swap external and internal phospholipids, and which are usually activated by Ca(2+), whilst the change in cytoplasmic conductivity may be due to K(+) efflux from intermediate conductance (IK) ion channels that are also activated by Ca(2+).
Collapse
Affiliation(s)
- H J Mulhall
- Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| | - A Cardnell
- Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| | - K F Hoettges
- Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| | - F H Labeed
- Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| | - M P Hughes
- Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| |
Collapse
|
37
|
Salido M, Vilches J. Intracellular Elemental Patterns of Apoptosis Resistance in Transdifferentiated Androgen-Dependent Prostatic Carcinoma Cells. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:865-877. [PMID: 27487730 DOI: 10.1017/s1431927616011454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The acquisition of neuroendocrine (NE) characteristics by prostate cancer (PC) cells relates to tumor progression and hormone resistance. PC cells may survive and function in androgen-deprived environments, where they could establish paracrine signaling networks, providing stimuli for the propagation of local carcinoma cells. We previously demonstrated, using electron probe X-ray microanalysis (EPXMA), in LNCaP, PC-3, and Du 145 cell lines that apoptosis is associated with intracellular elemental changes, and that the NE secretory products, bombesin and calcitonin, inhibit etoposide-induced apoptosis, as well as some of these elemental changes. In this study, LNCaP cells were induced in vitro to transdifferentiate under androgen deprivation, to mimic the role of NE cells in the apoptotic activity of transdifferentiated androgen-dependent PC cells. Changes in intracellular ion content associated with apoptosis, assessed by EPXMA, demonstrate that the transdifferentiated LNCaP cells are resistant to etoposide-induced apoptosis and also to the etoposide-induced elemental changes. The aggressive malignant potential of PC with neuroendocrine differentiation, associated with hormonal independence, is partly because of the ability that most NE tumor cells have to escape apoptosis, which can enhance the malignant properties of tumor cells and may have therapeutic implications as tumor cells are usually resistant to cytotoxic drugs as etoposide.
Collapse
Affiliation(s)
- Mercedes Salido
- Department of Histology,Servicio Central de Investigacion Biomedica y en Ciencias de la Salud (SC-IBM),School of Medicine,University of Cadiz,c/Dr. Marañon,3. 11002 Cádiz,Spain
| | - Jose Vilches
- Department of Histology,Servicio Central de Investigacion Biomedica y en Ciencias de la Salud (SC-IBM),School of Medicine,University of Cadiz,c/Dr. Marañon,3. 11002 Cádiz,Spain
| |
Collapse
|
38
|
Abstract
Activation of ion channels and pores are essential steps during regulated cell death. Channels and pores participate in execution of apoptosis, necroptosis and other forms of caspase-independent cell death. Within the program of regulated cell death, these channels are strategically located. Ion channels can shrink cells and drive them towards apoptosis, resulting in silent, i.e. immunologically unrecognized cell death. Alternatively, activation of channels can induce cell swelling, disintegration of the cell membrane, and highly immunogenic necrotic cell death. The underlying cell death pathways are not strictly separated as identical stimuli may induce cell shrinkage and apoptosis when applied at low strength, but may also cause cell swelling at pronounced stimulation, resulting in regulated necrosis. Nevertheless, the precise role of ion channels during regulated cell death is far from being understood, as identical channels may support regulated death in some cell types, but may cause cell proliferation, cancer development, and metastasis in others. Along this line, the phospholipid scramblase and Cl(-)/nonselective channel anoctamin 6 (ANO6) shows interesting features, as it participates in apoptotic cell death during lower levels of activation, thereby inducing cell shrinkage. At strong activation, e.g. by stimulation of purinergic P2Y7 receptors, it participates in pore formation, causes massive membrane blebbing, cell swelling, and membrane disintegration. The LRRC8 proteins deserve much attention as they were found to have a major role in volume regulation, apoptotic cell shrinkage and resistance towards anticancer drugs.
Collapse
Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
| |
Collapse
|
39
|
Alterations of proteins in MDCK cells during acute potassium deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:683-696. [DOI: 10.1016/j.bbapap.2016.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/05/2016] [Accepted: 03/10/2016] [Indexed: 11/18/2022]
|
40
|
Frajese GV, Benvenuto M, Fantini M, Ambrosin E, Sacchetti P, Masuelli L, Giganti MG, Modesti A, Bei R. Potassium increases the antitumor effects of ascorbic acid in breast cancer cell lines in vitro. Oncol Lett 2016; 11:4224-4234. [PMID: 27313770 DOI: 10.3892/ol.2016.4506] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 02/08/2016] [Indexed: 12/17/2022] Open
Abstract
Ascorbic acid (A) has been demonstrated to exhibit anti-cancer activity in association with chemotherapeutic agents. Potassium (K) is a regulator of cellular proliferation. In the present study, the biological effects of A and K bicarbonate, alone or in combination (A+K), on breast cancer cell lines were evaluated. The survival of cancer cells was determined by sulforhodamine B cell proliferation assay, while analysis of the cell cycle distribution was conducted via fluorescence-activated cell sorting. In addition, the expression of signaling proteins was analyzed upon treatment. The results indicated that there was a heterogeneous response of the different cell lines to A and K, and the best effects were achieved by A+K and A treatment. The interaction between A+K indicated an additive or synergistic effect. In addition, A+K increased the percentage of cells in the sub-G1 phase of the cell cycle, and was the most effective treatment in activating the degradation of poly(adenosine diphosphate-ribose) polymerase-1. In the breast cancer cell line MCF-7, A+K induced the appearance of the 18 kDa isoform of B-cell lymphoma-2-associated X protein (Bax), which is a more potent inducer of apoptosis than the full-length Bax-p21. The effects of A and K on the phosphorylation of extracellular signal-regulated kinase (ERK)1 and ERK2 were heterogeneous. In addition, treatment with K, A and A+K inhibited the expression of nuclear factor-κB. Overall, the results of the present study indicated that K potentiated the anti-tumoral effects of A in breast cancer cells in vitro.
Collapse
Affiliation(s)
- Giovanni Vanni Frajese
- Department of Sports Science, Human and Health, University of Rome 'Foro Italico', Rome I-00135, Italy
| | - Monica Benvenuto
- Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Rome I-00133, Italy
| | - Massimo Fantini
- Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Rome I-00133, Italy
| | - Elena Ambrosin
- Department of Sports Science, Human and Health, University of Rome 'Foro Italico', Rome I-00135, Italy
| | - Pamela Sacchetti
- Department of Experimental Medicine, University of Rome 'Sapienza', Rome I-00185, Italy
| | - Laura Masuelli
- Department of Experimental Medicine, University of Rome 'Sapienza', Rome I-00185, Italy
| | - Maria Gabriella Giganti
- Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Rome I-00133, Italy
| | - Andrea Modesti
- Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Rome I-00133, Italy
| | - Roberto Bei
- Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Rome I-00133, Italy
| |
Collapse
|
41
|
Shabala S, Bose J, Fuglsang AT, Pottosin I. On a quest for stress tolerance genes: membrane transporters in sensing and adapting to hostile soils. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1015-31. [PMID: 26507891 DOI: 10.1093/jxb/erv465] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Abiotic stresses such as salinity, drought, and flooding severely limit food and fibre production and result in penalties of in excess of US$100 billion per annum to the agricultural sector. Improved abiotic stress tolerance to these environmental constraints via traditional or molecular breeding practices requires a good understanding of the physiological and molecular mechanisms behind roots sensing of hostile soils, as well as downstream signalling cascades to effectors mediating plant adaptive responses to the environment. In this review, we discuss some common mechanisms conferring plant tolerance to these three major abiotic stresses. Central to our discussion are: (i) the essentiality of membrane potential maintenance and ATP production/availability and its use for metabolic versus adaptive responses; (ii) reactive oxygen species and Ca(2+) 'signatures' mediating stress signalling; and (iii) cytosolic K(+) as the common denominator of plant adaptive responses. We discuss in detail how key plasma membrane and tonoplast transporters are regulated by various signalling molecules and processes observed in plants under stress conditions (e.g. changes in membrane potential; cytosolic pH and Ca(2+); reactive oxygen species; polyamines; abscisic acid) and how these stress-induced changes are related to expression and activity of specific ion transporters. The reported results are then discussed in the context of strategies for breeding crops with improved abiotic stress tolerance. We also discuss a classical trade-off between tolerance and yield, and possible avenues for resolving this dilemma.
Collapse
Affiliation(s)
- Sergey Shabala
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia
| | - Jayakumar Bose
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia
| | - Anja Thoe Fuglsang
- Department of Plant and Environmental Science, University of Copenhagen, DK-1871 Frederiksberg, Denmark
| | - Igor Pottosin
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, 28045 Colima, México
| |
Collapse
|
42
|
Volkov V. Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes. FRONTIERS IN PLANT SCIENCE 2015; 6:873. [PMID: 26579140 PMCID: PMC4621421 DOI: 10.3389/fpls.2015.00873] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/01/2015] [Indexed: 05/18/2023]
Abstract
Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowledge about mechanisms of ion transport and individual genes of ion transport proteins. Initially, the Review describes methods to measure ion fluxes, the independent set of techniques ensures robust and reliable basement for quantitative approach. The Review briefly summarizes current data concerning Na(+) and K(+) concentrations in cells, refers to primary thermodynamics of ion transport and gives special attention to individual ion channels and transporters. Simplified scheme of a plant cell with known transport systems at the plasma membrane and tonoplast helps to imagine the complexity of ion transport and allows choosing specific transporters for modulating ion transport. The complexity is enhanced by the influence of cell size and cell wall on ion transport. Special attention is given to ion transporters and to potassium and sodium transport by HKT, HAK, NHX, and SOS1 proteins. Comparison between non-selective cation channels and ion transporters reveals potential importance of ion transporters and the balance between the two pathways of ion transport. Further on the Review describes in detail several successful attempts to overexpress or knockout ion transporters for changing salinity tolerance. Future perspectives are questioned with more attention given to promising candidate ion channels and transporters for altered expression. Potential direction of increasing salinity tolerance by modifying ion channels and transporters using single point mutations is discussed and questioned. An alternative approach from synthetic biology is to create new regulation networks using novel transport proteins with desired properties for transforming agricultural crops. The approach had not been widely used earlier; it leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis. Summarizing, several potential ways are aimed at required increase in salinity tolerance of plants of interest.
Collapse
Affiliation(s)
- Vadim Volkov
- Faculty of Life Sciences and Computing, London Metropolitan UniversityLondon, UK
| |
Collapse
|
43
|
Peter T, Bissinger R, Lang F. Erythrocyte Shrinkage and Cell Membrane Scrambling after Exposure to the Ionophore Nonactin. Basic Clin Pharmacol Toxicol 2015; 118:107-12. [DOI: 10.1111/bcpt.12455] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/09/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Thomas Peter
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Rosi Bissinger
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Florian Lang
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| |
Collapse
|
44
|
Atwell BJ, Greenway H, Colmer TD. Efficient use of energy in anoxia-tolerant plants with focus on germinating rice seedlings. THE NEW PHYTOLOGIST 2015; 206:36-56. [PMID: 25472708 DOI: 10.1111/nph.13173] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/09/2014] [Indexed: 05/08/2023]
Abstract
Anoxia tolerance in plants is distinguished by direction of the sparse supply of energy to processes crucial to cell maintenance and sometimes to growth, as in rice seedlings. In anoxic rice coleoptiles energy is used to synthesise proteins, take up K(+) , synthesise cell walls and lipids, and in cell maintenance. Maintenance of electrochemical H(+) gradients across the tonoplast and plasma membrane is crucial for solute compartmentation and thus survival. These gradients sustain some H(+) -solute cotransport and regulate cytoplasmic pH. Pyrophosphate (PPi ), the alternative energy donor to ATP, allows direction of energy to the vacuolar H(+) -PPi ase, sustaining H(+) gradients across the tonoplast. When energy production is critically low, operation of a biochemical pHstat allows H(+) -solute cotransport across plasma membranes to continue for at least for 18 h. In active (e.g. growing) cells, PPi produced during substantial polymer synthesis allows conversion of PPi to ATP by PPi -phosphofructokinase (PFK). In quiescent cells with little polymer synthesis and associated PPi formation, the PPi required by the vacuolar H(+) -PPi ase and UDPG pyrophosphorylase involved in sucrose mobilisation via sucrose synthase might be produced by conversion of ATP to PPi through reversible glycolytic enzymes, presumably pyruvate orthophosphate dikinase. These hypotheses need testing with species characterised by contrasting anoxia tolerance.
Collapse
Affiliation(s)
- Brian J Atwell
- Department of Biological Sciences, Faculty of Science, Macquarie University, Sydney, 2109, NSW, Australia
| | - Hank Greenway
- School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
| | - Timothy D Colmer
- School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
| |
Collapse
|
45
|
Hoang TML, Williams B, Khanna H, Dale J, Mundree SG. Physiological basis of salt stress tolerance in rice expressing the antiapoptotic gene SfIAP. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:1168-1177. [PMID: 32481066 DOI: 10.1071/fp13308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/20/2014] [Indexed: 06/11/2023]
Abstract
Programmed cell death-associated genes, especially antiapoptosis-related genes have been reported to confer tolerance to a wide range of biotic and abiotic stresses in dicotyledonous plants such as tobacco (Nicotiana tabacum L.) and tomato (Solanum lycopersicum L.). This is the first time the antiapoptotic gene SfIAP was transformed into a monocotyledonous representative: rice (Oryza sativa L.). Transgenic rice strains expressing SfIAP were generated by the Agrobacterium-mediated transformation method and rice embryogenic calli, and assessed for their ability to confer tolerance to salt stress at both the seedling and reproductive stages using a combination of molecular, agronomical, physiological and biochemical techniques. The results show that plants expressing SfIAP have higher salt tolerance levels in comparison to the wild-type and vector controls. By preventing cell death at the onset of salt stress and maintaining the cell membrane's integrity, SfIAP transgenic rice plants can retain plant water status, ion homeostasis, photosynthetic efficiency and growth to combat salinity successfully.
Collapse
Affiliation(s)
- Thi My Linh Hoang
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, PO Box 2434, Brisbane, Qld 4001, Australia
| | - Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, PO Box 2434, Brisbane, Qld 4001, Australia
| | - Harjeet Khanna
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, PO Box 2434, Brisbane, Qld 4001, Australia
| | - James Dale
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, PO Box 2434, Brisbane, Qld 4001, Australia
| | - Sagadevan G Mundree
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, PO Box 2434, Brisbane, Qld 4001, Australia
| |
Collapse
|
46
|
Shabala S, Shabala L, Barcelo J, Poschenrieder C. Membrane transporters mediating root signalling and adaptive responses to oxygen deprivation and soil flooding. PLANT, CELL & ENVIRONMENT 2014; 37:2216-33. [PMID: 24689809 DOI: 10.1111/pce.12339] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 05/20/2023]
Abstract
This review provides a comprehensive assessment of a previously unexplored topic: elucidating the role that plasma- and organelle-based membrane transporters play in plant-adaptive responses to flooding. We show that energy availability and metabolic shifts under hypoxia and anoxia are critical in regulating membrane-transport activity. We illustrate the high tissue and time dependence of this regulation, reveal the molecular identity of transporters involved and discuss the modes of their regulation. We show that both reduced oxygen availability and accumulation of transition metals in flooded roots result in a reduction in the cytosolic K(+) pool, ultimately determining the cell's fate and transition to programmed cell death (PCD). This process can be strongly affected by hypoxia-induced changes in the amino acid pool profile and, specifically, ϒ-amino butyric acid (GABA) accumulation. It is suggested that GABA plays an important regulatory role, allowing plants to proceed with H2 O2 signalling to activate a cascade of genes that mediate plant adaptation to flooding while at the same time, preventing the cell from entering a 'suicide program'. We conclude that progress in crop breeding for flooding tolerance can only be achieved by pyramiding the numerous physiological traits that confer efficient energy maintenance, cytosolic ion homeostasis, and reactive oxygen species (ROS) control and detoxification.
Collapse
Affiliation(s)
- Sergey Shabala
- School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia
| | | | | | | |
Collapse
|
47
|
Zeng F, Konnerup D, Shabala L, Zhou M, Colmer TD, Zhang G, Shabala S. Linking oxygen availability with membrane potential maintenance and K+ retention of barley roots: implications for waterlogging stress tolerance. PLANT, CELL & ENVIRONMENT 2014; 37:2325-38. [PMID: 25132404 DOI: 10.1111/pce.12422] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 05/24/2023]
Abstract
Oxygen deprivation is a key determinant of root growth and functioning under waterlogging. In this work, changes in net K(+) flux and membrane potential (MP) of root cells were measured from elongation and mature zones of two barley varieties under hypoxia and anoxia conditions in the medium, and as influenced by ability to transport O2 from the shoot. We show that O2 deprivation results in an immediate K(+) loss from roots, in a tissue- and time-specific manner, affecting root K(+) homeostasis. Both anoxia and hypoxia induced transient membrane depolarization; the extent of this depolarization varied depending on severity of O2 stress and was less pronounced in a waterlogging-tolerant variety. Intact roots of barley were capable of maintaining H(+) -pumping activity under hypoxic conditions while disrupting O2 transport from shoot to root resulted in more pronounced membrane depolarization under O2 -limited conditions and in anoxia a rapid loss of the cell viability. It is concluded that the ability of root cells to maintain MP and cytosolic K(+) homeostasis is central to plant performance under waterlogging, and efficient O2 transport from the shoot may enable operation of the plasma membrane H(+) -ATPase in roots even under conditions of severe O2 limitation in the soil solution.
Collapse
Affiliation(s)
- Fanrong Zeng
- School of Land and Food, University of Tasmania, Hobart, Tasmania, 7001, Australia; Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | | | | | | | | | | | | |
Collapse
|
48
|
Chen D, Song M, Mohamad O, Yu SP. Inhibition of Na+/K+-ATPase induces hybrid cell death and enhanced sensitivity to chemotherapy in human glioblastoma cells. BMC Cancer 2014; 14:716. [PMID: 25255962 PMCID: PMC4190379 DOI: 10.1186/1471-2407-14-716] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/22/2014] [Indexed: 11/10/2022] Open
Abstract
Background Glioblastoma multiforme (GBM) is very difficult to treat with conventional anti-cancer/anti-apoptotic drugs. We tested the hypothesis that inhibition of Na+/K+-ATPase causes a mixed or hybrid form of concurrent apoptosis and necrosis and therefore should enhance anti-cancer effects of chemotherapy on glioblastoma cells. Methods In human LN229 and drug-resistant T98G glioblastoma cell cultures, cell death and signal pathways were measured using immunocytochemistry and Western blotting. Fluorescent dyes were applied to measure intracellular Ca2+, Na+ and K+ changes. Results The specific Na+/K+-ATPase blocker ouabain (0.1 - 10 μM) induced cell death and disruption of K+ homeostasis in a time- and concentration-dependent manner. Annexin-V translocation and caspase-3 activation indicated an apoptotic component in ouabain cytoxicity, which was accompanied with reduced Bcl-2 expression and mitochondrial membrane potential. Ouabain-induced cell death was partially attenuated by the caspase inhibitor Z-VAD (100 μM). Consistently, the K+ ionophore valinomycin initiated apoptosis in LN229 cells in a K+ efflux-dependent manner. Ouabain caused an initial cell swell, which was followed by a sustained cell volume decrease. Electron microscopy revealed ultrastructural features of both apoptotic and necrotic alterations in the same cells. Finally, human T98G glioblastoma cells that are resistant to the chemotherapy drug temozolomide (TMZ) showed a unique high expression of the Na+/K+-ATPase α2 and α3 subunits compared to the TMZ-sensitive cell line LN229 and normal human astrocytes. At low concentrations, ouabain selectively killed T98G cells. Knocking down the α3 subunit sensitized T98G cells to TMZ and caused more cell death. Conclusion This study suggests that inhibition of Na+/K+-ATPase triggers hybrid cell death and serves as an underlying mechanism for an enhanced chemotherapy effect on glioblastoma cells. Electronic supplementary material The online version of this article (doi:10.1186/1471-2407-14-716) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | | | | | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
49
|
Malik A, Bissinger R, Jilani K, Lang F. Stimulation of erythrocyte cell membrane scrambling by nystatin. Basic Clin Pharmacol Toxicol 2014; 116:47-52. [PMID: 24894380 DOI: 10.1111/bcpt.12279] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/26/2014] [Indexed: 12/11/2022]
Abstract
The antifungal ionophore nystatin dissipates the Na(+) and K(+) gradients across the cell membrane, leading to cellular gain of Na(+) and cellular loss of K(+) . The increase of cellular Na(+) concentration may result in Ca(2+) accumulation in exchange for Na(+) . Increase of cytosolic Ca(2+) activity ([Ca(2+) ]i ) and loss of cellular K(+) foster apoptosis-like suicidal erythrocyte death or eryptosis, which is characterised by cell shrinkage and cell membrane scrambling leading to phosphatidylserine exposure at the erythrocyte surface. The present study explored whether nystatin stimulates eryptosis. Cell volume was estimated from forward scatter (FSC), phosphatidylserine exposure from annexin V binding and [Ca(2+) ]i from Fluo3-fluorescence in flow cytometry. A 48-hr exposure to nystatin (15 μg/ml) was followed by a significant increase of [Ca(2+) ]i , a significant increase of annexin V binding and a significant decrease of FSC. The annexin V binding after nystatin treatment was significantly blunted in the nominal absence of extracellular Ca(2+) . Partial replacement of extracellular Na(+) with extracellular K(+) blunted the nystatin-induced erythrocyte shrinkage but increased [Ca(2+) ]i and annexin V binding. Nystatin triggers cell membrane scrambling, an effect at least partially due to entry of extracellular Ca(2+) .
Collapse
Affiliation(s)
- Abaid Malik
- Department of Physiology, University of Tuebingen, Tuebingen, Germany
| | | | | | | |
Collapse
|
50
|
Shabala S, Pottosin I. Regulation of potassium transport in plants under hostile conditions: implications for abiotic and biotic stress tolerance. PHYSIOLOGIA PLANTARUM 2014; 151:257-79. [PMID: 24506225 DOI: 10.1111/ppl.12165] [Citation(s) in RCA: 274] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/15/2013] [Accepted: 01/13/2014] [Indexed: 05/18/2023]
Abstract
Intracellular potassium homeostasis is a prerequisite for the optimal operation of plant metabolic machinery and plant's overall performance. It is controlled by K(+) uptake, efflux and intracellular and long-distance relocation, mediated by a large number of K(+) -selective and non-selective channels and transporters located at both plasma and vacuolar membranes. All abiotic and biotic stresses result in a significant disturbance to intracellular potassium homeostasis. In this work, we discuss molecular mechanisms and messengers mediating potassium transport and homeostasis focusing on four major environmental stresses: salinity, drought, flooding and biotic factors. We argue that cytosolic K(+) content may be considered as one of the 'master switches' enabling plant transition from the normal metabolism to 'hibernated state' during first hours after the stress exposure and then to a recovery phase. We show that all these stresses trigger substantial disturbance to K(+) homeostasis and provoke a feedback control on K(+) channels and transporters expression and post-translational regulation of their activity, optimizing K(+) absorption and usage, and, at the extreme end, assisting the programmed cell death. We discuss specific modes of regulation of the activity of K(+) channels and transporters by membrane voltage, intracellular Ca(2+) , reactive oxygen species, polyamines, phytohormones and gasotransmitters, and link this regulation with plant-adaptive responses to hostile environments.
Collapse
Affiliation(s)
- Sergey Shabala
- School of Agricultural Science, University of Tasmania, Hobart, Tas, 7001, Australia
| | | |
Collapse
|