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Postma AV, Rapp CK, Knoflach K, Volk AE, Lemke JR, Ackermann M, Regamey N, Latzin P, Celant L, Jansen SM, Bogaard HJ, Ilgun A, Alders M, van Spaendonck-Zwarts KY, Jonigk D, Klein C, Gräf S, Kubisch C, Houweling AC, Griese M. Biallelic variants in the calpain regulatory subunit CAPNS1 cause pulmonary arterial hypertension. GENETICS IN MEDICINE OPEN 2023; 1:100811. [PMID: 38230350 PMCID: PMC10790724 DOI: 10.1016/j.gimo.2023.100811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 04/06/2023] [Accepted: 04/10/2023] [Indexed: 01/18/2024]
Abstract
Purpose The aim of this study was to identify the monogenic cause of pulmonary arterial hypertension (PAH), a multifactorial and often fatal disease, in 2 unrelated consanguine families. Methods We performed exome sequencing and validated variant pathogenicity by whole-blood RNA and protein expression analysis in both families. Further RNA sequencing of preserved lung tissue was performed to investigate the consequences on selected genes that are involved in angiogenesis, proliferation, and apoptosis. Results We identified 2 rare biallelic variants in CAPNS1, encoding the regulatory subunit of calpain. The variants cosegregated with PAH in the families. Both variants lead to loss of function (LoF), which is demonstrated by aberrant splicing resulting in the complete absence of the CAPNS1 protein in affected patients. No other LoF CAPNS1 variant was identified in the genome data of more than 1000 patients with unresolved PAH. Conclusion The calpain holoenzyme was previously linked to pulmonary vascular development and progression of PAH in patients. We demonstrated that biallelic LoF variants in CAPNS1 can cause idiopathic PAH by the complete absence of CAPNS1 protein. Screening of this gene in patients who are affected by PAH, especially with suspected autosomal recessive inheritance, should be considered.
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Affiliation(s)
- Alex V. Postma
- Department of Medical Biology, Amsterdam University Medical Centre, Amsterdam, The Netherlands
- Department of Human Genetics, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Christina K. Rapp
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, LMU Klinikum, Ludwig Maximilians University of Munich, German Center for Lung Research (DZL), Munich, Germany
| | - Katrin Knoflach
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, LMU Klinikum, Ludwig Maximilians University of Munich, German Center for Lung Research (DZL), Munich, Germany
| | - Alexander E. Volk
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Johannes R. Lemke
- Institute of Human Genetics, Leipzig University Medical Center, Leipzig, Germany
- Center for Rare Diseases, Leipzig University Medical Center, Leipzig, Germany
| | - Maximilian Ackermann
- Institute of Functional and Clinical Anatomy, University Medical Centre, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nicolas Regamey
- Division of Paediatric Pulmonology, Children’s Hospital, Lucerne Cantonal Hospital, Lucerne, Switzerland
| | - Philipp Latzin
- Division of Paediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, University Hospital, University of Bern, Bern, Switzerland
| | - Lucas Celant
- Department of Pulmonary Medicine, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Samara M.A. Jansen
- Department of Pulmonary Medicine, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Harm J. Bogaard
- Department of Pulmonary Medicine, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Aho Ilgun
- Department of Human Genetics, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Mariëlle Alders
- Department of Human Genetics, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | | | - Danny Jonigk
- Institute of Pathology, Medizinische Hochschule Hannover, Hanover, Germany
| | - Christoph Klein
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, LMU Klinikum, Ludwig Maximilians University of Munich, German Center for Lung Research (DZL), Munich, Germany
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Heart and Lung Research Institute, Cambridge, United Kingdom
- NIHR BioResource for Translational Research–Rare Diseases, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Arjan C. Houweling
- Department of Human Genetics, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Matthias Griese
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, LMU Klinikum, Ludwig Maximilians University of Munich, German Center for Lung Research (DZL), Munich, Germany
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Shaikh S, Samanta K, Kar P, Roy S, Chakraborti T, Chakraborti S. m-Calpain-mediated cleavage of Na+/Ca2+ exchanger-1 in caveolae vesicles isolated from pulmonary artery smooth muscle. Mol Cell Biochem 2010; 341:167-80. [PMID: 20372982 DOI: 10.1007/s11010-010-0448-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 03/17/2010] [Indexed: 01/30/2023]
Abstract
Using m-calpain antibody, we have identified two major bands corresponding to the 80 kDa large and the 28 kDa small subunit of m-calpain in caveolae vesicles isolated from bovine pulmonary artery smooth muscle plasma membrane. In addition, 78, 35, and 18 kDa immunoreactive bands of m-calpain have also been detected. Casein zymogram studies also revealed the presence of m-calpain in the caveolae vesicles. We have also identified Na(+)/Ca(2+) exchanger-1 (NCX1) in the caveolae vesicles. Purification and N-terminal sequence analyses of these two proteins confirmed their identities as m-calpain and NCX1, respectively. We further sought to determine the role of m-calpain on calcium-dependent proteolytic cleavage of NCX1 in the caveolae vesicles. Treatment of the caveolae vesicles with the calcium ionophore, A23187 (1 microM) in presence of CaCl(2) (1 mM) appears to cleave NCX1 (120 kDa) to an 82 kDa fragment as revealed by immunoblot study using NCX1 monoclonal antibody; while pretreatment with the calpain inhibitors, calpeptin or MDL28170; or the Ca(2+) chelator, BAPTA-AM did not cause a discernible change in the NCX protein profile. In vitro cleavage of the purified NCX1 by the purified m-calpain supports this finding. The cleavage of NCX1 by m-calpain in the caveolae vesicles may be interpreted as an important mechanism of Ca(2+) overload, which could arise due to inhibition of Ca(2+) efflux by the forward-mode NCX and that could lead to sustained Ca(2+) overload in the smooth muscle leading to pulmonary hypertension.
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Affiliation(s)
- Soni Shaikh
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741235 West Bengal, India
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Submitochondrial localization of associated mu-calpain and calpastatin. Arch Biochem Biophys 2007; 470:176-86. [PMID: 18082616 DOI: 10.1016/j.abb.2007.11.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 11/28/2007] [Accepted: 11/29/2007] [Indexed: 12/20/2022]
Abstract
Recently, we have reported the presence of calpain-calpastatin system in mitochondria of bovine pulmonary smooth muscle [P. Kar, T. Chakraborti, S. Roy, R. Choudhury, S. Chakraborti, Arch. Biochem. Biophys. 466 (2007) 290-299]. Herein, we report its localization in the mitochondria. Immunoblot, immunoelectron microscopy and casein zymographic studies suggest that mu-calpain and calpastatin are present in the inner mitochondrial membrane; but not in the outer mitochondrial membrane or in the inter membrane space or in the matrix of the mitochondria. Co-immunoprecipitation studies suggest that mu-calpain-calpastatin is associated in the inner mitochondrial membrane. Additionally, the proteinase K and sodium carbonate treatments of the mitoplasts revealed that mu-calpain is integrally and calpastatin is peripherally embedded to the outer surface of inner mitochondrial membrane. These studies indicate that an association between mu-calpain and calpastatin occurs in the inner membrane towards the inter membrane space of the mitochondria, which provides better insight about the protease regulation towards initiation of apoptotic processes mediated by mitochondria.
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Kar P, Chakraborti T, Roy S, Choudhury R, Chakraborti S. Identification of calpastatin and μ-calpain and studies of their association in pulmonary smooth muscle mitochondria. Arch Biochem Biophys 2007; 466:290-9. [PMID: 17868638 DOI: 10.1016/j.abb.2007.07.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 07/16/2007] [Indexed: 11/22/2022]
Abstract
Using calpastatin antibody we have identified a 145 kDa major band along with two relatively minor bands at 120 kDa and 110 kDa calpastatin molecules in bovine pulmonary artery smooth muscle mitochondria. To the best of our knowledge this is first report regarding the identification of calpastatin in mitochondria. We also demonstrated the presence of micro-calpain in the mitochondria by immunoblot and casein zymogram studies. Immunoblot studies identified two major bands corresponding to the 80 kDa large and the 28 kDa small subunit of mu-calpain. Additionally 76 kDa, 40 kDa and 18 kDa immunoreactive bands have also been detected. Purification and N-terminal amino acid sequence analysis of the identified proteins confirmed their identity as mu-calpain and calpastatins. Immunoprecipitation study revealed molecular association between mu-calpain and calpastatin in the mitochondria indicating that calpastatin could play an important role in preventing uncontrolled activity of mu-calpain which otherwise may facilitate pulmonary hypertension, smooth muscle proliferation and apoptosis.
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Affiliation(s)
- Pulak Kar
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
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Samanta K, Kar P, Ghosh B, Chakraborti T, Chakraborti S. Localization of m-calpain and calpastatin and studies of their association in pulmonary smooth muscle endoplasmic reticulum. Biochim Biophys Acta Gen Subj 2007; 1770:1297-307. [PMID: 17656025 DOI: 10.1016/j.bbagen.2007.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 06/18/2007] [Accepted: 06/22/2007] [Indexed: 11/25/2022]
Abstract
Calpain and calpastatin have been demonstrated to play many physiological roles in a variety of systems. It, therefore, appears important to study their localization and association in different suborganelles. Using immunoblot studies, we have identified 80 kDa m-calpain in both lumen and membrane of ER isolated from bovine pulmonary artery smooth muscle. Treatment of the ER with Na(2)CO(3) and proteinase K demonstrated that 80 kDa catalytic subunit and 28 kDa regulatory subunit (Rs) of m-calpain, and the 110-kDa and 70-kDa calpastatin (Cs) forms are localized in the cytosolic side of the ER membrane. Coimmunoprecipitation studies revealed that m-calpain is associated with calpastatin in the cytosolic face of the ER membrane. We have also identified m-calpain activity both in the ER membrane and lumen by casein-zymography. The casein-zymogram has also been utilized to demonstrate differential pattern of the effects of reversible and irreversible cysteine protease inhibitors on m-calpain activity. Thus, a potential site of Cs regulation of m-calpain activity is created by positioning Cs, 80 kDa and 28 kDa m-calpain in the cytosolic face of ER membrane. However, such is not the case for the 80-kDa m-calpain found within the lumen of the ER because of the conspicuous absence of 28 kDa Rs of m-calpain and Cs in this locale.
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Affiliation(s)
- Krishna Samanta
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
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