Calpain-2 Activates Akt via the TGF~ 1-mTORC2 Pathway in Pulmonary Artery Smooth Muscle Cells

Hdl Handle:
http://hdl.handle.net/10675.2/618702
Title:
Calpain-2 Activates Akt via the TGF~ 1-mTORC2 Pathway in Pulmonary Artery Smooth Muscle Cells
Authors:
Abeyrathna, Prasanna
Abstract:
Calpain is a family of calcium-dependent nonlysosomal neutral cysteine endopeptidases. Akt is a serine/threonine kinase that belongs to the AGC kinases and plays important roles in cell survival, growth, proliferation, angiogenesis, and cell metabolism. Both calpain and Akt are downstream signaling molecules of platelet-derived growth factor (PDGF) and mediate PDGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. We found that inhibition of calpain-2 using the calpain inhibitor MDL28170 and calpain-2 siRNA attenuated Akt phosphorylation at serine-473 (S473) and threonine-308 (T308) as well as collagen synthesis and cell proliferation ofPASMCs induced by PDGF. Overexpression of calpain-2 in PASMCs induced dramatic increases in Akt phosphorylation at S4 73 and T308. Moreover, knockout of calpain attenuated Akt phosphorylation at S473 and T308 in smooth muscle of pulmonary arterioles of mice with chronic hypoxic pulmonary hypertension. The cell-permeable specific TGF~ receptor inhibitor SB431542 attenuated Akt phosphorylation at both S473 and T308 induced by PDGF and overexpressed calpain- 2 in PASMCs. Moreover, SB-431452 and knock down of ALK5 significantly reduced PDGF-induced collagen synthesis and cell proliferation of PASMCs. Nevertheless, neutralizing extracellular TGF~l using a cell-impermeable TGF~l neutralizing antibody did not affect PDGF-induced Akt phosphorylation at S473 and T308. Further, inhibition of mTORC2 by knocking down its component protein Rictor prevented Akt phosphorylation at S473 and T308 induced by PDGF and overexpressed calpain-2. These data provide the first evidence supporting that calpain-2 up-regulates PDGF-induced Akt phosphorylation via an intracrine TGF~ 1/mTORC2 mechanism.
Affiliation:
Deparment of Pharmacology and Toxicology
Issue Date:
23-Aug-2016
URI:
http://hdl.handle.net/10675.2/618702
Type:
Dissertation
Language:
en_US
Appears in Collections:
Department of Pharmacology and Toxicology Theses and Dissertations; Theses and Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.authorAbeyrathna, Prasannaen
dc.date.accessioned2016-08-23T19:15:36Z-
dc.date.available2016-08-23T19:15:36Z-
dc.date.issued2016-08-23-
dc.identifier.urihttp://hdl.handle.net/10675.2/618702-
dc.description.abstractCalpain is a family of calcium-dependent nonlysosomal neutral cysteine endopeptidases. Akt is a serine/threonine kinase that belongs to the AGC kinases and plays important roles in cell survival, growth, proliferation, angiogenesis, and cell metabolism. Both calpain and Akt are downstream signaling molecules of platelet-derived growth factor (PDGF) and mediate PDGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. We found that inhibition of calpain-2 using the calpain inhibitor MDL28170 and calpain-2 siRNA attenuated Akt phosphorylation at serine-473 (S473) and threonine-308 (T308) as well as collagen synthesis and cell proliferation ofPASMCs induced by PDGF. Overexpression of calpain-2 in PASMCs induced dramatic increases in Akt phosphorylation at S4 73 and T308. Moreover, knockout of calpain attenuated Akt phosphorylation at S473 and T308 in smooth muscle of pulmonary arterioles of mice with chronic hypoxic pulmonary hypertension. The cell-permeable specific TGF~ receptor inhibitor SB431542 attenuated Akt phosphorylation at both S473 and T308 induced by PDGF and overexpressed calpain- 2 in PASMCs. Moreover, SB-431452 and knock down of ALK5 significantly reduced PDGF-induced collagen synthesis and cell proliferation of PASMCs. Nevertheless, neutralizing extracellular TGF~l using a cell-impermeable TGF~l neutralizing antibody did not affect PDGF-induced Akt phosphorylation at S473 and T308. Further, inhibition of mTORC2 by knocking down its component protein Rictor prevented Akt phosphorylation at S473 and T308 induced by PDGF and overexpressed calpain-2. These data provide the first evidence supporting that calpain-2 up-regulates PDGF-induced Akt phosphorylation via an intracrine TGF~ 1/mTORC2 mechanism.en
dc.language.isoen_USen
dc.subjectPDGFen
dc.subjectHypertensionen
dc.subjectRictoren
dc.titleCalpain-2 Activates Akt via the TGF~ 1-mTORC2 Pathway in Pulmonary Artery Smooth Muscle Cellsen
dc.typeDissertationen
dc.contributor.departmentDeparment of Pharmacology and Toxicologyen
dc.description.advisorSu, Yunchaoen
dc.description.degreeDoctor of Philosophy with a Major in Pharmacologyen
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