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Ceron RH, Báez-Cruz FA, Palmer NJ, Carman PJ, Boczkowska M, Heuckeroth RO, Ostap EM, Dominguez R. Molecular mechanisms linking missense ACTG2 mutations to visceral myopathy. SCIENCE ADVANCES 2024; 10:eadn6615. [PMID: 38820162 PMCID: PMC11141634 DOI: 10.1126/sciadv.adn6615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 04/29/2024] [Indexed: 06/02/2024]
Abstract
Visceral myopathy is a life-threatening disease characterized by muscle weakness in the bowel, bladder, and uterus. Mutations in smooth muscle γ-actin (ACTG2) are the most common cause of the disease, but the mechanisms by which the mutations alter muscle function are unknown. Here, we examined four prevalent ACTG2 mutations (R40C, R148C, R178C, and R257C) that cause different disease severity and are spread throughout the actin fold. R178C displayed premature degradation, R148C disrupted interactions with actin-binding proteins, R40C inhibited polymerization, and R257C destabilized filaments. Because these mutations are heterozygous, we also analyzed 50/50 mixtures with wild-type (WT) ACTG2. The WT/R40C mixture impaired filament nucleation by leiomodin 1, and WT/R257C produced filaments that were easily fragmented by smooth muscle myosin. Smooth muscle tropomyosin isoform Tpm1.4 partially rescued the defects of R40C and R257C. Cryo-electron microscopy structures of filaments formed by R40C and R257C revealed disrupted intersubunit contacts. The biochemical and structural properties of the mutants correlate with their genotype-specific disease severity.
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Affiliation(s)
- Rachel H. Ceron
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- The Children’s Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Faviolla A. Báez-Cruz
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas J. Palmer
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Peter J. Carman
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert O. Heuckeroth
- The Children’s Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - E. Michael Ostap
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Wang Y, Panicker IS, Anesi J, Sargisson O, Atchison B, Habenicht AJR. Animal Models, Pathogenesis, and Potential Treatment of Thoracic Aortic Aneurysm. Int J Mol Sci 2024; 25:901. [PMID: 38255976 PMCID: PMC10815651 DOI: 10.3390/ijms25020901] [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: 12/18/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Thoracic aortic aneurysm (TAA) has a prevalence of 0.16-0.34% and an incidence of 7.6 per 100,000 person-years, accounting for 1-2% of all deaths in Western countries. Currently, no effective pharmacological therapies have been identified to slow TAA development and prevent TAA rupture. Large TAAs are treated with open surgical repair and less invasive thoracic endovascular aortic repair, both of which have high perioperative mortality risk. Therefore, there is an urgent medical need to identify the cellular and molecular mechanisms underlying TAA development and rupture to develop new therapies. In this review, we summarize animal TAA models including recent developments in porcine and zebrafish models: porcine models can assess new therapeutic devices or intervention strategies in a large mammal and zebrafish models can employ large-scale small-molecule suppressor screening in microwells. The second part of the review covers current views of TAA pathogenesis, derived from recent studies using these animal models, with a focus on the roles of the transforming growth factor-beta (TGFβ) pathway and the vascular smooth muscle cell (VSMC)-elastin-contractile unit. The last part discusses TAA treatment options as they emerge from recent preclinical studies.
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Affiliation(s)
- Yutang Wang
- Discipline of Life Science, Institute of Innovation, Science and Sustainability, Federation University Australia, Ballarat, VIC 3353, Australia; (I.S.P.)
| | - Indu S. Panicker
- Discipline of Life Science, Institute of Innovation, Science and Sustainability, Federation University Australia, Ballarat, VIC 3353, Australia; (I.S.P.)
| | - Jack Anesi
- Discipline of Life Science, Institute of Innovation, Science and Sustainability, Federation University Australia, Ballarat, VIC 3353, Australia; (I.S.P.)
| | - Owen Sargisson
- Discipline of Life Science, Institute of Innovation, Science and Sustainability, Federation University Australia, Ballarat, VIC 3353, Australia; (I.S.P.)
| | - Benjamin Atchison
- Discipline of Life Science, Institute of Innovation, Science and Sustainability, Federation University Australia, Ballarat, VIC 3353, Australia; (I.S.P.)
| | - Andreas J. R. Habenicht
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-Universität München (LMU), 80336 Munich, Germany;
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Kast DJ, Jansen S. Purification of modified mammalian actin isoforms for in vitro reconstitution assays. Eur J Cell Biol 2023; 102:151363. [PMID: 37778219 PMCID: PMC10872616 DOI: 10.1016/j.ejcb.2023.151363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/19/2023] [Accepted: 09/26/2023] [Indexed: 10/03/2023] Open
Abstract
In vitro reconstitution assays using purified actin have greatly improved our understanding of cytoskeletal dynamics and their regulation by actin-binding proteins. However, early purification methods consisted of harsh conditions to obtain pure actin and often did not include correct maturation and obligate modification of the isolated actin monomers. Novel insights into the folding requirements and N-terminal processing of actin as well as a better understanding of the interaction of actin with monomer sequestering proteins such as DNaseI, profilin and gelsolin, led to the development of more gentle approaches to obtain pure recombinant actin isoforms with known obligate modifications. This review summarizes the approaches that can be employed to isolate natively folded endogenous and recombinant actin from tissues and cells. We further emphasize the use and limitations of each method and describe how these methods can be implemented to study actin PTMs, disease-related actin mutations and novel actin-like proteins.
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Affiliation(s)
- David J Kast
- Department of Cell Biology and Physiology, Washington University in St. Louis, Saint Louis, MO, 63110, United States.
| | - Silvia Jansen
- Department of Cell Biology and Physiology, Washington University in St. Louis, Saint Louis, MO, 63110, United States.
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Majumder S, Chattopadhyay A, Wright JM, Guan P, Buja LM, Kwartler CS, Milewicz DM. Pericentrin deficiency in smooth muscle cells augments atherosclerosis through HSF1-driven cholesterol biosynthesis and PERK activation. JCI Insight 2023; 8:e173247. [PMID: 37937642 PMCID: PMC10721278 DOI: 10.1172/jci.insight.173247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/27/2023] [Indexed: 11/09/2023] Open
Abstract
Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) is caused by biallelic loss-of-function variants in pericentrin (PCNT), and premature coronary artery disease (CAD) is a complication of the syndrome. Histopathology of coronary arteries from patients with MOPDII who died of CAD in their 20s showed extensive atherosclerosis. Hyperlipidemic mice with smooth muscle cell-specific (SMC-specific) Pcnt deficiency (PcntSMC-/-) exhibited significantly greater atherosclerotic plaque burden compared with similarly treated littermate controls despite similar serum lipid levels. Loss of PCNT in SMCs induced activation of heat shock factor 1 (HSF1) and consequently upregulated the expression and activity of HMG-CoA reductase (HMGCR), the rate-limiting enzyme in cholesterol biosynthesis. The increased cholesterol biosynthesis in PcntSMC-/- SMCs augmented PERK signaling and phenotypic modulation compared with control SMCs. Treatment with the HMGCR inhibitor, pravastatin, blocked the augmented SMC modulation and reduced plaque burden in hyperlipidemic PcntSMC-/- mice to that of control mice. These data support the notion that Pcnt deficiency activates cellular stress to increase SMC modulation and plaque burden, and targeting this pathway with statins in patients with MOPDII has the potential to reduce CAD in these individuals. The molecular mechanism uncovered further emphasizes SMC cytosolic stress and HSF1 activation as a pathway driving atherosclerotic plaque formation independently of cholesterol levels.
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Affiliation(s)
- Suravi Majumder
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
| | - Abhijnan Chattopadhyay
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
| | - Jamie M. Wright
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
| | - Pujun Guan
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
| | - L. Maximilian Buja
- Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Callie S. Kwartler
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
| | - Dianna M. Milewicz
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, and
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Kaw K, Chattopadhyay A, Guan P, Chen J, Majumder S, Duan XY, Ma S, Zhang C, Kwartler CS, Milewicz DM. Smooth muscle α-actin missense variant promotes atherosclerosis through modulation of intracellular cholesterol in smooth muscle cells. Eur Heart J 2023; 44:2713-2726. [PMID: 37377039 PMCID: PMC10393072 DOI: 10.1093/eurheartj/ehad373] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/15/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
AIMS The variant p.Arg149Cys in ACTA2, which encodes smooth muscle cell (SMC)-specific α-actin, predisposes to thoracic aortic disease and early onset coronary artery disease in individuals without cardiovascular risk factors. This study investigated how this variant drives increased atherosclerosis. METHODS AND RESULTS Apoe-/- mice with and without the variant were fed a high-fat diet for 12 weeks, followed by evaluation of atherosclerotic plaque formation and single-cell transcriptomics analysis. SMCs explanted from Acta2R149C/+ and wildtype (WT) ascending aortas were used to investigate atherosclerosis-associated SMC phenotypic modulation. Hyperlipidemic Acta2R149C/+Apoe-/- mice have a 2.5-fold increase in atherosclerotic plaque burden compared to Apoe-/- mice with no differences in serum lipid levels. At the cellular level, misfolding of the R149C α-actin activates heat shock factor 1, which increases endogenous cholesterol biosynthesis and intracellular cholesterol levels through increased HMG-CoA reductase (HMG-CoAR) expression and activity. The increased cellular cholesterol in Acta2R149C/+ SMCs induces endoplasmic reticulum stress and activates PERK-ATF4-KLF4 signaling to drive atherosclerosis-associated phenotypic modulation in the absence of exogenous cholesterol, while WT cells require higher levels of exogenous cholesterol to drive phenotypic modulation. Treatment with the HMG-CoAR inhibitor pravastatin successfully reverses the increased atherosclerotic plaque burden in Acta2R149C/+Apoe-/- mice. CONCLUSION These data establish a novel mechanism by which a pathogenic missense variant in a smooth muscle-specific contractile protein predisposes to atherosclerosis in individuals without hypercholesterolemia or other risk factors. The results emphasize the role of increased intracellular cholesterol levels in driving SMC phenotypic modulation and atherosclerotic plaque burden.
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Affiliation(s)
- Kaveeta Kaw
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Abhijnan Chattopadhyay
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Pujun Guan
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Jiyuan Chen
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Suravi Majumder
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Xue-yan Duan
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Shuangtao Ma
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
- Department of Medicine, Michigan State University, 1355 Bogue St, B226B Life Sciences, East Lansing, MI 48824, USA
| | - Chen Zhang
- Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, and Department of Cardiovascular Surgery, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX 77030, USA
| | - Callie S Kwartler
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Dianna M Milewicz
- Division of Medical Genetics, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
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Ojha KR, Kim H, Padgham S, Hopkins L, Zamen RJ, Chattopadhyay A, Han G, Milewicz DM, Massett MP, Trache A. Smooth Muscle-Alpha Actin R149C Pathogenic Variant Downregulates Integrin Recruitment at Cell-Matrix Adhesions and Decreases Cellular Contractility. Int J Mol Sci 2023; 24:9616. [PMID: 37298565 PMCID: PMC10253315 DOI: 10.3390/ijms24119616] [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: 04/18/2023] [Revised: 05/21/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Thoracic aortic aneurysm is found in patients with ACTA2 pathogenic variants. ACTA2 missense variants are associated with impaired aortic smooth muscle cell (SMC) contraction. This study tested the hypothesis that the Acta2R149C/+ variant alters actin isoform expression and decreases integrin recruitment, thus, reducing aortic contractility. Stress relaxation measurements in thoracic aortic rings showed two functional regimes with a reduction of stress relaxation in the aorta from Acta2R149C/+ mice at low tension, but not at high tension values. Contractile responses to phenylephrine and potassium chloride were 50% lower in Acta2R149C/+ mice than in wild-type (WT) mice. Additionally, SMC were immunofluorescently labeled for specific proteins and imaged by confocal or total internal reflection fluorescence microscopy. The quantification of protein fluorescence of Acta2R149C/+ SMC showed a downregulation in smooth muscle α-actin (SMα-actin) and a compensatory upregulation of smooth muscle γ-actin (SMγ-actin) compared to WT cells. These results suggest that downregulation of SMα-actin leads to reduced SMC contractility, while upregulation of SMγ-actin may lead to increased SMC stiffness. Decreased α5β1 and α2β1 integrin recruitment at cell-matrix adhesions further reduce the ability of mutant cells to participate in cell-matrix crosstalk. Collectively, the results suggest that mutant Acta2R149C/+ aortic SMC have reduced contractility and interaction with the matrix, which are potential long-term contributing factors to thoracic aortic aneurysms.
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Affiliation(s)
- Krishna R. Ojha
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Hyoseon Kim
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX 79409, USA
| | - Samuel Padgham
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Laura Hopkins
- Department of Epidemiology and Statistics, Texas A&M University Health Science Center, College Station, TX 77843, USA
| | - Robert J. Zamen
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Abhijnan Chattopadhyay
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Gang Han
- Department of Epidemiology and Statistics, Texas A&M University Health Science Center, College Station, TX 77843, USA
| | - Dianna M. Milewicz
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Michael P. Massett
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX 79409, USA
| | - Andreea Trache
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX 77807, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
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7
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Guo DC, Duan X, Mimnagh K, Cecchi AC, Marin IC, Yu Y, Velasco WV, Lee K, Zhu X, Murdock DR, Leal SM, Wheeler MM, Smith J, Bamshad MJ, Milewicz DM. An FBN1 deep intronic variant is associated with pseudoexon formation and a variable Marfan phenotype in a five generation family. Clin Genet 2023; 103:704-708. [PMID: 36861389 PMCID: PMC10159920 DOI: 10.1111/cge.14322] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/09/2023] [Accepted: 02/12/2023] [Indexed: 03/03/2023]
Abstract
Exome sequencing of genes associated with heritable thoracic aortic disease (HTAD) failed to identify a pathogenic variant in a large family with Marfan syndrome (MFS). A genome-wide linkage analysis for thoracic aortic disease identified a peak at 15q21.1, and genome sequencing identified a novel deep intronic FBN1 variant that segregated with thoracic aortic disease in the family (LOD score 2.7) and was predicted to alter splicing. RT-PCR and bulk RNA sequencing of RNA harvested from fibroblasts explanted from the affected proband revealed an insertion of a pseudoexon between exons 13 and 14 of the FBN1 transcript, predicted to lead to nonsense mediated decay (NMD). Treating the fibroblasts with an NMD inhibitor, cycloheximide, greatly improved the detection of the pseudoexon-containing transcript. Family members with the FBN1 variant had later onset aortic events and fewer MFS systemic features than typical for individuals with haploinsufficiency of FBN1. Variable penetrance of the phenotype and negative genetic testing in MFS families should raise the possibility of deep intronic FBN1 variants and the need for additional molecular studies.
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Affiliation(s)
- Dong-Chuan Guo
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Xueyan Duan
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Kathleen Mimnagh
- Department of Internal Medicine, WVU School of Medicine-Charleston Division (Retired), Morgantown, West Virginia, USA
| | - Alana C Cecchi
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Isabella C Marin
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Yang Yu
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Walter V Velasco
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Kwanghyuk Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Xue Zhu
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - David R Murdock
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
| | - Suzanne M Leal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Marsha M Wheeler
- Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Josh Smith
- Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Dianna M Milewicz
- Department of Internal Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, USA
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