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Egly CL, Barny LA, Do T, McDonald EF, Knollmann BC, Plate L. The proteostasis interactomes of trafficking-deficient variants of the voltage-gated potassium channel K V11.1 associated with long QT syndrome. J Biol Chem 2024; 300:107465. [PMID: 38876300 PMCID: PMC11284683 DOI: 10.1016/j.jbc.2024.107465] [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: 03/28/2024] [Revised: 05/16/2024] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
The voltage-gated potassium ion channel KV11.1 plays a critical role in cardiac repolarization. Genetic variants that render Kv11.1 dysfunctional cause long QT syndrome (LQTS), which is associated with fatal arrhythmias. Approximately 90% of LQTS-associated variants cause intracellular protein transport (trafficking) dysfunction, which pharmacological chaperones like E-4031 can rescue. Protein folding and trafficking decisions are regulated by chaperones, protein quality control factors, and trafficking machinery comprising the cellular proteostasis network. Here, we test whether trafficking dysfunction is associated with alterations in the proteostasis network of pathogenic Kv11.1 variants and whether pharmacological chaperones can normalize the proteostasis network of responsive variants. We used affinity-purification coupled with tandem mass tag-based quantitative mass spectrometry to assess protein interaction changes of WT KV11.1 or trafficking-deficient channel variants in the presence or absence of E-4031. We identified 572 core KV11.1 protein interactors. Trafficking-deficient variants KV11.1-G601S and KV11.1-G601S-G965∗ had significantly increased interactions with proteins responsible for folding, trafficking, and degradation compared to WT. We confirmed previous findings that the proteasome is critical for KV11.1 degradation. Our report provides the first comprehensive characterization of protein quality control mechanisms of KV11.1. We find extensive interactome remodeling associated with trafficking-deficient KV11.1 variants and with pharmacological chaperone rescue of KV11.1 cell surface expression. The identified protein interactions could be targeted therapeutically to improve KV11.1 trafficking and treat LQTS.
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Affiliation(s)
- Christian L Egly
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA
| | - Lea A Barny
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Tri Do
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA
| | - Eli F McDonald
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Björn C Knollmann
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA.
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Egly CL, Barny L, Do T, McDonald EF, Plate L, Knollmann BC. The proteostasis interactomes of trafficking-deficient K V 11.1 variants associated with Long QT Syndrome and pharmacological chaperone rescue. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.574410. [PMID: 38352392 PMCID: PMC10862811 DOI: 10.1101/2024.01.31.574410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Introduction The voltage gated potassium ion channel K V 11.1 plays a critical role in cardiac repolarization. Genetic variants that render Kv11.1 dysfunctional cause Long QT Syndrome (LQTS), which is associated with fatal arrhythmias. Approximately 90% of LQTS-associated variants cause intracellular protein transport (trafficking) dysfunction, which can be rescued by pharmacological chaperones like E-4031. Protein folding and trafficking decisions are regulated by chaperones, protein quality control factors, and trafficking machinery, comprising the cellular proteostasis network. Here, we test whether trafficking dysfunction is associated with alterations in the proteostasis network of pathogenic Kv11.1 variants, and whether pharmacological chaperones can normalize the proteostasis network of responsive variants. Methods We used affinity-purification coupled with tandem mass tag-based quantitative mass spectrometry to assess protein interaction changes in human embryonic kidney (HEK293) cells expressing wild-type (WT) K V 11.1 or trafficking-deficient channel variants in the presence or absence of E-4031. Resultsa We identified 573 core K V 11.1 protein interactors. Both variants K V 11.1-G601S and K V 11.1-G601S-G965* had significantly increased interactions with proteins responsible for folding, trafficking, and degradation compared to WT. We found that proteasomal degradation is a key component for K V 11.1 degradation and that the K V 11.1-G601S-G965* variant was more responsive to E-4031 treatment. This suggests a role in the C-terminal domain and the ER retention motif of K V 11.1 in regulating trafficking. Conclusion Our report characterizes the proteostasis network of K V 11.1, two trafficking deficient K V 11.1 variants, and variants treated with a pharmacological chaperone. The identified protein interactions could be targeted therapeutically to improve K V 11.1 trafficking and treat Long QT Syndrome.
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Pant P, Chitme H, Sircar R, Prasad R, Prasad HO. Genome-wide association study for single nucleotide polymorphism associated with mural and cumulus granulosa cells of PCOS (polycystic ovary syndrome) and non-PCOS patients. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2023. [DOI: 10.1186/s43094-023-00475-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
Abstract
Background
The genetic make-up of local granulosa cells and their function in the pathophysiology of polycystic ovary syndrome (PCOS) is crucial to a full comprehension of the disorder. The major purpose of this study was to compare the Single Nucleotide Polymorphism (SNP) of cumulus granulosa cells (CGCs) and mural granulosa cells (MGCs) between healthy individuals and women with PCOS using genome-wide association analysis (GWA). A case–control study was conducted in a total of 24 women diagnosed with PCOS and 24 healthy non-PCOS women of reproductive age aggregated into 4 samples of 6 patients each. GWA studies entail several processes, such as cell separation, cellular DNA extraction, library preparation followed by interpretation using bioinformatics databases. SNP locations were identified by reference gene also involves the use of Matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) (MALDI-TOF-MS) for the first sorting. Hybridization with the gene chip was followed by reading the SNP genotypes according to the publications in the literature. TASSEL (Trait Analysis by aSSociation, Evolution and Linkage) program and methods were used for GWA studies.
Results
An aggregate of 21,039 SNP calls were obtained from our samples. Genes of autoimmune illnesses, obesity, inflammatory illnesses, nervous system diseases such as retinitis pigmentosa, autism, neural tube defects, and Alzheimer's disease; and various malignancies such as lung cancer, colorectal cancer, breast cancer were also identified in these cells. Gene ranking score reveals that granulosa cells carry key genes of neurological system and reproductive systems especially in brain and testis, respectively.
Conclusions
Mural and Cumulus Granulosa cells were shown to have the PCOS directly and indirectly related genes MMP9, PRKAA2, COMT and HP. We found that the expression of ARID4B, MUC5AC, NID2, CREBBP, GNB1, KIF2C, COL18A1, and HNRNPC by these cells may contribute to PCOS.
Graphical abstract
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Nguyen NH, Brodsky JL. The cellular pathways that maintain the quality control and transport of diverse potassium channels. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194908. [PMID: 36638864 PMCID: PMC9908860 DOI: 10.1016/j.bbagrm.2023.194908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
Potassium channels are multi-subunit transmembrane proteins that permit the selective passage of potassium and play fundamental roles in physiological processes, such as action potentials in the nervous system and organismal salt and water homeostasis, which is mediated by the kidney. Like all ion channels, newly translated potassium channels enter the endoplasmic reticulum (ER) and undergo the error-prone process of acquiring post-translational modifications, folding into their native conformations, assembling with other subunits, and trafficking through the secretory pathway to reach their final destinations, most commonly the plasma membrane. Disruptions in these processes can result in detrimental consequences, including various human diseases. Thus, multiple quality control checkpoints evolved to guide potassium channels through the secretory pathway and clear potentially toxic, aggregation-prone misfolded species. We will summarize current knowledge on the mechanisms underlying potassium channel quality control in the secretory pathway, highlight diseases associated with channel misfolding, and suggest potential therapeutic routes.
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Affiliation(s)
- Nga H Nguyen
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA.
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Cai D, Zheng Z, Jin X, Fu Y, Cen L, Ye J, Song Y, Lian J. The Advantages, Challenges, and Future of Human-Induced Pluripotent Stem Cell Lines in Type 2 Long QT Syndrome. J Cardiovasc Transl Res 2023; 16:209-220. [PMID: 35976484 DOI: 10.1007/s12265-022-10298-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/23/2022] [Indexed: 02/05/2023]
Abstract
Type 2 long QT syndrome (LQT2) is the second most common subtype of long QT syndrome and is caused by mutations in KCHN2 encoding the rapidly activating delayed rectifier potassium channel vital for ventricular repolarization. Sudden cardiac death is a sentinel event of LQT2. Preclinical diagnosis by genetic testing is potentially life-saving.Traditional LQT2 models cannot wholly recapitulate genetic and phenotypic features; therefore, there is a demand for a reliable experimental model. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) meet this challenge. This review introduces the advantages of the hiPSC-CM model over the traditional model and discusses how hiPSC-CM and gene editing are used to decipher mechanisms of LQT2, screen for cardiotoxicity, and identify therapeutic strategies, thus promoting the realization of precision medicine for LQT2 patients.
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Affiliation(s)
- Dihui Cai
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
| | - Zequn Zheng
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
- Department of Cardiovascular, First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Xiaojun Jin
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
| | - Yin Fu
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
| | - Lichao Cen
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
| | - Jiachun Ye
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China
| | - Yongfei Song
- Department of Cardiovascular, Ningbo Institute of Innovation for Combined Medicine and Engineering, Ningbo, China
| | - Jiangfang Lian
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo University, Zhejiang Province, Ningbo, China.
- Department of Cardiovascular, Ningbo Institute of Innovation for Combined Medicine and Engineering, Ningbo, China.
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Karlova M, Abramochkin DV, Pustovit KB, Nesterova T, Novoseletsky V, Loussouarn G, Zaklyazminskaya E, Sokolova OS. Disruption of a Conservative Motif in the C-Terminal Loop of the KCNQ1 Channel Causes LQT Syndrome. Int J Mol Sci 2022; 23:ijms23147953. [PMID: 35887302 PMCID: PMC9316142 DOI: 10.3390/ijms23147953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 02/04/2023] Open
Abstract
We identified a single nucleotide variation (SNV) (c.1264A > G) in the KCNQ1 gene in a 5-year-old boy who presented with a prolonged QT interval. His elder brother and mother, but not sister and father, also had this mutation. This missense mutation leads to a p.Lys422Glu (K422E) substitution in the Kv7.1 protein that has never been mentioned before. We inserted this substitution in an expression plasmid containing Kv7.1 cDNA and studied the electrophysiological characteristics of the mutated channel expressed in CHO-K1, using the whole-cell configuration of the patch-clamp technique. Expression of the mutant Kv7.1 channel in both homo- and heterozygous conditions in the presence of auxiliary subunit KCNE1 results in a significant decrease in tail current densities compared to the expression of wild-type (WT) Kv7.1 and KCNE1. This study also indicates that K422E point mutation causes a dominant negative effect. The mutation was not associated with a trafficking defect; the mutant channel protein was confirmed to localize at the cell membrane. This mutation disrupts the poly-Lys strip in the proximal part of the highly conserved cytoplasmic A−B linker of Kv7.1 that was not shown before to be crucial for channel functioning.
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Affiliation(s)
- Maria Karlova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (M.K.); (D.V.A.); (K.B.P.); (V.N.)
| | - Denis V. Abramochkin
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (M.K.); (D.V.A.); (K.B.P.); (V.N.)
| | - Ksenia B. Pustovit
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (M.K.); (D.V.A.); (K.B.P.); (V.N.)
| | - Tatiana Nesterova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Ekaterinburg, Russia;
- Institute of Natural Sciences and Mathematics, Ural Federal University, 620075 Ekaterinburg, Russia
| | - Valery Novoseletsky
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (M.K.); (D.V.A.); (K.B.P.); (V.N.)
- Biology Department, Shenzhen MSU-BIT University, Shenzhen 517182, China
| | - Gildas Loussouarn
- Nantes Université, CNRS, INSERM, l’institut du Thorax, F-44000 Nantes, France;
| | | | - Olga S. Sokolova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (M.K.); (D.V.A.); (K.B.P.); (V.N.)
- Biology Department, Shenzhen MSU-BIT University, Shenzhen 517182, China
- Correspondence: or
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Bi X, Zhang S, Jiang H, Ma W, Li Y, Lu W, Yang F, Wei Z. Mechanistic Insights Into Inflammation-Induced Arrhythmias: A Simulation Study. Front Physiol 2022; 13:843292. [PMID: 35711306 PMCID: PMC9196871 DOI: 10.3389/fphys.2022.843292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 04/25/2022] [Indexed: 11/29/2022] Open
Abstract
Cardiovascular diseases are the primary cause of death of humans, and among these, ventricular arrhythmias are the most common cause of death. There is plausible evidence implicating inflammation in the etiology of ventricular fibrillation (VF). In the case of systemic inflammation caused by an overactive immune response, the induced inflammatory cytokines directly affect the function of ion channels in cardiomyocytes, leading to a prolonged action potential duration (APD). However, the mechanistic links between inflammatory cytokine-induced molecular and cellular influences and inflammation-associated ventricular arrhythmias need to be elucidated. The present study aimed to determine the potential impact of systemic inflammation on ventricular electrophysiology by means of multiscale virtual heart models. The experimental data on the ionic current of three major cytokines [i.e., tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1β), and interleukin-6 (IL-6)] were incorporated into the cell model, and the effects of each cytokine and their combined effect on the cell action potential (AP) were evaluated. Moreover, the integral effect of these cytokines on the conduction of excitation waves was also investigated in a tissue model. The simulation results suggested that inflammatory cytokines significantly prolonged APD, enhanced the transmural and regional repolarization heterogeneities that predispose to arrhythmias, and reduced the adaptability of ventricular tissue to fast heart rates. In addition, simulated pseudo-ECGs showed a prolonged QT interval—a manifestation consistent with clinical observations. In summary, the present study provides new insights into ventricular arrhythmias associated with inflammation.
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Affiliation(s)
- Xiangpeng Bi
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Shugang Zhang
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Huasen Jiang
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Wenjian Ma
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Yuanfei Li
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Weigang Lu
- Department of Educational Technology, Ocean University of China, Qingdao, China
| | - Fei Yang
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
| | - Zhiqiang Wei
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
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Ng CA, Vandenberg JI. When it takes two to get one into trouble. Heart Rhythm 2021; 19:293-294. [PMID: 34687922 DOI: 10.1016/j.hrthm.2021.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 11/04/2022]
Affiliation(s)
- Chai-Ann Ng
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia, and St Vincent's Clinical School, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Jamie I Vandenberg
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia, and St Vincent's Clinical School, UNSW Sydney, Darlinghurst, New South Wales, Australia.
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