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Sendo S, Kiosses WB, Yang S, Wu DJ, Lee DWK, Liu L, Aschner Y, Vela AJ, Downey GP, Santelli E, Bottini N. Clustering of phosphatase RPTPα promotes Src signaling and the arthritogenic action of synovial fibroblasts. Sci Signal 2023; 16:eabn8668. [PMID: 37402225 PMCID: PMC10544828 DOI: 10.1126/scisignal.abn8668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/15/2023] [Indexed: 07/06/2023]
Abstract
Receptor-type protein phosphatase α (RPTPα) promotes fibroblast-dependent arthritis and fibrosis, in part, by enhancing the activation of the kinase SRC. Synovial fibroblasts lining joint tissue mediate inflammation and tissue damage, and their infiltration into adjacent tissues promotes disease progression. RPTPα includes an ectodomain and two intracellular catalytic domains (D1 and D2) and, in cancer cells, undergoes inhibitory homodimerization, which is dependent on a D1 wedge motif. Through single-molecule localization and labeled molecule interaction microscopy of migrating synovial fibroblasts, we investigated the role of RPTPα dimerization in the activation of SRC, the migration of synovial fibroblasts, and joint damage in a mouse model of arthritis. RPTPα clustered with other RPTPα and with SRC molecules in the context of actin-rich structures. A known dimerization-impairing mutation in the wedge motif (P210L/P211L) and the deletion of the D2 domain reduced RPTPα-RPTPα clustering; however, it also unexpectedly reduced RPTPα-SRC association. The same mutations also reduced recruitment of RPTPα to actin-rich structures and inhibited SRC activation and cellular migration. An antibody against the RPTPα ectodomain that prevented the clustering of RPTPα also inhibited RPTPα-SRC association and SRC activation and attenuated fibroblast migration and joint damage in arthritic mice. A catalytically inactivating RPTPα-C469S mutation protected mice from arthritis and reduced SRC activation in synovial fibroblasts. We conclude that RPTPα clustering retains it to actin-rich structures to promote SRC-mediated fibroblast migration and can be modulated through the extracellular domain.
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Affiliation(s)
- Sho Sendo
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - William B. Kiosses
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Shen Yang
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Dennis J. Wu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Daniel W. K. Lee
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Lin Liu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Allison J. Vela
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Gregory P. Downey
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
- Department of Pediatrics, National Jewish Health, Denver, Colorado
| | - Eugenio Santelli
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Nunzio Bottini
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Medicine, Kao Autoimmunity Institute, Cedars Sinai Medical Center, Los Angeles, CA, USA
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Aschner Y, Correll KA, Beke K, Foster DG, Roybal HM, Nelson MR, Meador CL, Strand M, Anderson KC, Moore CM, Reynolds PR, Kopf KW, Burnham EL, Downey GP. PTPα Promotes Fibroproliferative Responses After Acute Lung Injury. Am J Physiol Lung Cell Mol Physiol 2022; 323:L69-L83. [PMID: 35670474 DOI: 10.1152/ajplung.00436.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Acute Respiratory Distress Syndrome (ARDS) is a major healthcare problem, accounting for significant mortality and long-term disability. Approximately 25% of patients with ARDS will develop an over-exuberant fibrotic response, termed fibroproliferative ARDS (FP-ARDS) that portends a poor prognosis and increased mortality. The cellular pathologic processes that drive FP-ARDS remain incompletely understood. We have previously shown that the transmembrane receptor-type tyrosine phosphatase Protein Tyrosine Phosphatase-a (PTPa) promotes pulmonary fibrosis in preclinical murine models through regulation of TGF-b signaling. In this study, we examine the role of PTPa in the pathogenesis of FP-ARDS in a preclinical murine model of acid (HCl)-induced acute lung injury. We demonstrate that while mice genetically deficient in PTPa (Ptpra-/-) are susceptible to early HCl-induced lung injury, they exhibit markedly attenuated fibroproliferative responses. Additionally, early pro-fibrotic gene expression is reduced in lung tissue after acute lung injury in Ptpra-/- mice, and stimulation of naïve lung fibroblasts with the BAL fluid from these mice results in attenuated fibrotic outcomes compared to wild type littermate controls. Transcriptomic analyses demonstrates reduced Extracellular Matrix (ECM) deposition and remodeling in mice genetically deficient in PTPa. Importantly, human lung fibroblasts modified with a CRISPR-targeted deletion of PTPRA exhibit reduced expression of profibrotic genes in response to TGF-β stimulation, demonstrating the importance of PTPa in human lung fibroblasts. Together, these findings demonstrate that PTPa is a key regulator of fibroproliferative processes following acute lung injury and could serve as a therapeutic target for patients at risk for poor long-term outcomes in ARDS.
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Affiliation(s)
- Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States.,Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Kelly A Correll
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Keriann Beke
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Daniel G Foster
- Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States
| | - Helen M Roybal
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Meghan R Nelson
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Carly L Meador
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Matthew Strand
- Division of Biostatistics, National Jewish Health, Denver, CO, United States
| | - Kelsey C Anderson
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, United States
| | - Camille M Moore
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States
| | - Paul R Reynolds
- Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States
| | - Katrina W Kopf
- Office of Academic Affairs, National Jewish Health, Denver, CO, United States
| | - Ellen L Burnham
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States
| | - Gregory P Downey
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States.,Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States.,Office of Academic Affairs, National Jewish Health, Denver, CO, United States.,Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
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Impaired Leptin Signalling in Obesity: Is Leptin a New Thermolipokine? Int J Mol Sci 2021; 22:ijms22126445. [PMID: 34208585 PMCID: PMC8235268 DOI: 10.3390/ijms22126445] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/03/2021] [Accepted: 06/10/2021] [Indexed: 12/17/2022] Open
Abstract
Leptin is a principal adipose-derived hormone mostly implicated in the regulation of energy balance through the activation of anorexigenic neuronal pathways. Comprehensive studies have established that the maintenance of certain concentrations of circulating leptin is essential to avoid an imbalance in nutrient intake. Indeed, genetic modifications of the leptin/leptin receptor axis and the obesogenic environment may induce changes in leptin levels or action in a manner that accelerates metabolic dysfunctions, resulting in a hyperphagic status and adipose tissue expansion. As a result, a vicious cycle begins wherein hyperleptinaemia and leptin resistance occur, in turn leading to increased food intake and fat enlargement, which is followed by leptin overproduction. In addition, in the context of obesity, a defective thermoregulatory response is associated with impaired leptin signalling overall within the ventromedial nucleus of the hypothalamus. These recent findings highlight the role of leptin in the regulation of adaptive thermogenesis, thus suggesting leptin to be potentially considered as a new thermolipokine. This review provides new insight into the link between obesity, hyperleptinaemia, leptin resistance and leptin deficiency, focusing on the ability to restore leptin sensitiveness by way of enhanced thermogenic responses and highlighting novel anti-obesity therapeutic strategies.
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