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Xavier S, Sahu RK, Bontha SV, Mass V, Taylor RP, Megyesi J, Thielens NM, Portilla D. Complement C1r serine protease contributes to kidney fibrosis. Am J Physiol Renal Physiol 2019; 317:F1293-F1304. [PMID: 31509012 DOI: 10.1152/ajprenal.00357.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have previously reported that complement activation precedes the development of kidney fibrosis; however, little is known about the cellular mechanisms involved in this transition. We hypothesized that increased expression of C1 complex protease C1r, the initiator of complement activation, contributes to tubulointerstitial fibrosis and tested this idea in mice with global deletion of C1r. Although expression of C1r in untreated wild-type (WT) mice was higher in the liver compared with kidney tissue, administration of folic acid (FA) led to upregulation of C1r mRNA and protein levels only in kidney tissue. Immunohistochemistry and in situ hybridization experiments localized increased expression of C1r and C1s proteases to renal tubular epithelial cells. C1r-null mice had reduced acute tubular injury and inflammation measured 2 days after FA administration compared with WT mice. C1r deletion reduced expression of C1s, C3 fragment formation, and organ fibrosis measured 14 days after FA administration. Differential gene expression performed in kidney tissue demonstrated that C1r-null mice had reduced expression of genes associated with the acute phase response, complement, proliferation of connective tissue cells (e.g., platelet-derived growth factor receptor-β), and reduced expression of genes associated with inflammation compared with FA-treated WT mice. In vitro experiments in renal epithelial cells demonstrated that C1s expression is dependent on increased C1r expression and that interferon-γ induces the expression of these two proteases. We conclude that increased expression of C1 complex proteases is associated with increased tissue inflammation and complement C3 formation and represents an important pathogenic mechanism leading to FA-mediated tubulointerstitial fibrosis.
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Affiliation(s)
- Sandhya Xavier
- Division of Nephrology, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, Virginia
| | - Ranjit K Sahu
- Division of Nephrology, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, Virginia
| | - Sai Vineela Bontha
- Methodist University of Tennessee Transplant Institute, Memphis, Tennessee
| | - Valeria Mass
- Methodist University of Tennessee Transplant Institute, Memphis, Tennessee
| | - Ronald P Taylor
- Department of Biochemistry, University of Virginia, Charlottesville, Virginia
| | - Judit Megyesi
- University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nicole M Thielens
- University of Grenoble Alpes, Centre National de la Recherche Scientifique, Commissariat à l'énergie Atomique et aux Énergies Alternatives, L'Institut de Biologie Structurale, Grenoble, France
| | - Didier Portilla
- Division of Nephrology, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, Virginia.,Salem Veterans Affairs Medical Center, Salem, Virginia
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Morgan BP. Chapter 10 Activation and control of the complement system. Immunobiology 1996. [DOI: 10.1016/s1569-2582(96)80078-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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