A Novel Role for Calpain in the Endothelial Dysfunction Induced by Activation of Angiotensin II Type 1 Receptor Signaling

Abstract

Rationale The cytosolic protease calpain has been recently implicated in the vascular remodeling of angiotensin II (AngII) type-1 receptor (AT1r) signaling. The role of AngII/AT1r/calpain signaling on endothelial function, an important and early determinant of vascular pathology, remains though totally unknown. Accordingly, we investigated the role of calpain in the endothelial dysfunction of AngII. Objective To demonstrate a mechanistic role for calpain in the endothelial dysfunction induced by AngII/AT1r signaling. To establish endothelial-expressed calpains as an important target of AT1r signaling. Methods and Results Subchronic administration of nonpressor doses of AngII to rats and mice significantly increased vascular calpain activity via AT1r signaling. Intravital microscopy studies revealed that activation of vascular expressed calpains causes endothelial dysfunction with increased leukocyte-endothelium interactions and albumin permeability in the microcirculation. Western blot and immunohistochemistry studies confirmed that AngII/AT1r signaling preferentially activates the constitutively expressed μ-calpain isoform and demonstrated a calpain-dependent degradation of IκBα, along with upregulation of NF-κB-regulated endothelial cell adhesion molecules (eCAMs). These physiological and biochemical parameters were nearly normalized following inhibition of AT1r or calpain in vivo. Antisense depletion studies in microvascular endothelial cells along with knockout and transgenic mouse studies further confirmed the role of μ-calpain in the endothelial adhesiveness induced by AngII. Conclusions This study uncovers a novel role for calpain in the endothelial dysfunction of AngII/AT1r signaling and establishes the calpain system as a novel molecular target of the vascular protective action of RAS inhibition. Our results may have significant clinical implications in vascular disease.

Calpain inhibition stabilizes the platelet proteome and reactivity in diabetes

“…44 Other calpain inhibitors attenuate angiotensin II-induced abdominal aortic aneurysms and atherosclerosis in LDL receptordeficient mice 45 and angiotensin II-induced endothelial dysfunction in rats and mice. 46 The results of the present study, together with the studies showing a beneficial effect of calpain inhibition in vascular disease, highlight the potential of calpain inhibition for the treatment of the vascular complications of type 2 diabetes. However, future efforts should focus on the development of compounds devoid of the problems of calpain isoform selectivity and specificity versus other proteases, 47 which have hampered the progression of calpain inhibitors into clinical trials.…”

Calpain-dependent Cleavage of N-cadherin Is Involved in the Progression of Post-myocardial Infarction Remodeling

“…In cultured vascular smooth muscle cells, stimulation with angiotensin II (Ang II) has increased the calpain activity through transactivation of epidermal growth factor receptor and systemic overexpression of calpastatin blunted cardiac hypertro- phy and perivascular inflammation in Ang II-infused mice (53). A recent study showed that calpain activation mediated Ang II-induced endothelial dysfunction in rodents (54). It is intriguing that activation of Ang II receptor signaling by locally produced Ang II and mechanical stress (28) may lead to calpain activation and thereby promote LV remodeling after MI.…”

A New Concept: A 1-42 Generates a Hyperfunctional Proteolytic NCX3 Fragment That Delays Caspase-12 Activation and Neuronal Death

“…Nitrocellulose membranes were incubated with rabbit-polyclonal antibody anti-NCX3 (1: 3000; kindly provided by K. Philipson), or mouse monoclonal anti-NCX1 (1:500; Swant), or mouse monoclonal anti-tubulin (1:1000), or rabbit polyclonal antibodies anti-caspase-12 (1:1000) and goat polyclonal anti-calpain (1:500) (Santa Cruz Biotechnology). Calpain activation was assessed by immunoblot analysis using a primary antibody that recognizes the calpain large subunit domain, which is autolyzed in active calpain from the full length calpain at 130 kDa, as already reported (Goll et al, 2003;Scalia et al, 2011;Selimovic et al, 2011).…”