Cyclosporine A-Induced Calcineurin Isoform Specific Matrix Metalloproteinases (MMP-2 and MMP-9) Expression in Renal Fibroblasts
Location
Georgia
Start Date
16-5-2017 1:00 PM
Description
Background: It has been shown that long-term treatment with the potent immunosuppressive drug cyclosporine A (CsA) results in chronic nephrotoxicity. Its immunosuppressive properties are due to the results of the inhibition of the calcium- and calmodulin-dependent phosphatase protein calcineurin A (CnA). The catalytic subunit of CnA has 3 isoforms: alpha, beta and gamma. The CnA alpha and beta isoforms are expressed ubiquitously in a wide variety of tissues (particularly the kidney) while the CnA gamma isoform is restricted to the testes and brain. Additionally, chronic nephrotoxicity has been associated with an imbalance of extracellular matrix (ECM) synthesis and degradation which may result in an accumulation of ECM molecules.
Objective: This study evaluates whether the expressions of matrix metalloproteinases (MMP-2 and MMP-9) induced by CsA is calcineurin isoform specific.
Methods and Results: Wild-type (WT), CnA alpha knockout (CnA alpha -/-) and CnA beta knockout (CnA beta -/-) kidney fibroblast cell lines (an in vitro innovative tool that was previously created in our lab) were treated with CsA at 10 ng/ml for 24 and 48 hrs. Western blot results demonstrated that CsA induced an increase in MMP-9 protein levels in CnA beta -/- fibroblasts, but not in wild-type and CnA alpha -/- fibroblasts. The protein levels were 2 to 2.5-fold higher vs. basal levels in CnA beta -/- cultured in the absence of CsA. In contrast, CsA did not induce an increase in MMP-2 protein levels in WT, CnA alpha -/- nor CnA beta -/- renal fibroblasts.
Conclusions: These results indicate that loss of the CnA alpha isoform contributes to the CsA-induced upregulation of MMP-9 while loss of CnA beta does not. As such, understanding the role of calcineurin A isoforms in the regulation of the homeostasis of ECM degradation in the kidney after long-term CsA treatment needs to be further investigated.
Embargo Period
6-26-2017
Cyclosporine A-Induced Calcineurin Isoform Specific Matrix Metalloproteinases (MMP-2 and MMP-9) Expression in Renal Fibroblasts
Georgia
Background: It has been shown that long-term treatment with the potent immunosuppressive drug cyclosporine A (CsA) results in chronic nephrotoxicity. Its immunosuppressive properties are due to the results of the inhibition of the calcium- and calmodulin-dependent phosphatase protein calcineurin A (CnA). The catalytic subunit of CnA has 3 isoforms: alpha, beta and gamma. The CnA alpha and beta isoforms are expressed ubiquitously in a wide variety of tissues (particularly the kidney) while the CnA gamma isoform is restricted to the testes and brain. Additionally, chronic nephrotoxicity has been associated with an imbalance of extracellular matrix (ECM) synthesis and degradation which may result in an accumulation of ECM molecules.
Objective: This study evaluates whether the expressions of matrix metalloproteinases (MMP-2 and MMP-9) induced by CsA is calcineurin isoform specific.
Methods and Results: Wild-type (WT), CnA alpha knockout (CnA alpha -/-) and CnA beta knockout (CnA beta -/-) kidney fibroblast cell lines (an in vitro innovative tool that was previously created in our lab) were treated with CsA at 10 ng/ml for 24 and 48 hrs. Western blot results demonstrated that CsA induced an increase in MMP-9 protein levels in CnA beta -/- fibroblasts, but not in wild-type and CnA alpha -/- fibroblasts. The protein levels were 2 to 2.5-fold higher vs. basal levels in CnA beta -/- cultured in the absence of CsA. In contrast, CsA did not induce an increase in MMP-2 protein levels in WT, CnA alpha -/- nor CnA beta -/- renal fibroblasts.
Conclusions: These results indicate that loss of the CnA alpha isoform contributes to the CsA-induced upregulation of MMP-9 while loss of CnA beta does not. As such, understanding the role of calcineurin A isoforms in the regulation of the homeostasis of ECM degradation in the kidney after long-term CsA treatment needs to be further investigated.
Comments
Second-place winner of Excellence in Research-Residents/Fellows award