calpain and Respiratory-Distress-Syndrome

This study aimed to investigate the role of endothelial Piezo1 in mediating ventilator-induced lung injury secondary to acute respiratory distress syndrome (ARDS).. Rats and lung endothelial cells (ECs) were transfected with Piezo1 shRNA (shPiezo1) and Piezo1 siRNA, respectively, to knock down Piezo1. Intratracheal instillation or incubation with lipopolysaccharide (LPS) was used to establish an ARDS model, and high tidal volume (HVT) ventilation or 20% cyclic stretch (CS) was administered to simulate a two-hit injury. Lung injury, alterations in lung endothelial barrier, disruption of adherens junctions (AJs), and Ca. Lung vascular hyperpermeability was further increased in ARDS rats following HVT ventilation, which was abrogated in shPiezo1-treated rats. 20% CS led to severer rupture of AJs following LPS stimulation as indicated by immunofluorescence staining. The internalization and degradation of VE-cadherin were blocked by knockdown of Piezo1. Additionally, 20% CS induced Piezo1 activation, manifesting as elevated intracellular Ca. Excessive mechanical stretch during ARDS induces the activation of Piezo1 channel and its downstream target, calpain, via Ca

Topics: Adherens Junctions; Animals; Antigens, CD; Cadherins; Calcium; Calpain; Down-Regulation; Endothelial Cells; Gene Knockdown Techniques; Male; Membrane Proteins; Protein Aggregates; Proteolysis; Rats; Rats, Wistar; Respiratory Distress Syndrome; Tidal Volume; Ventilator-Induced Lung Injury

Nuclear factor-kappaB (NF-kappaB) is a transcription factor which plays a pivotal role in the induction of genes involved in the response to injury and inflammation. Calpain I inhibitor is a potent antioxidant which is an effective inhibitor of NF-kappaB. This study examined whether the postulate that calpain I inhibitor attenuates experimental acute pancreatitis.. In a murine model we measured NF-kappaB activation, expression of intercellular adhesion molecule (ICAM) 1, nitrotyrosine, inducible nitric oxide synthase (iNOS), nuclear enzyme poly(ADP-ribose) synthetase (PARS), myeloperoxidase, malondialdehyde, amylase and lipase and determined histological evidence of lung and pancreas injury in four groups: control (saline only), cerulein, calpain I inhibitor plus cerulein and calpain I inhibitor plus saline.. Intraperitoneal injection of cerulein in mice resulted in severe, acute pancreatitis characterised by oedema, neutrophil infiltration, tissue haemorrhage and necrosis and elevated serum levels of amylase and lipase. Infiltration of pancreatic and lung tissue with neutrophils (measured as increase in myeloperoxidase activity) was associated with enhanced lipid peroxidation (increased tissue levels of malondialdehyde). Immunohistochemical examination demonstrated a marked increase in immunoreactivity for nitrotyrosine, iNOS and PARS in the pancreas and lung of cerulein-treated mice. In contrast, pre-treatment with calpain I inhibitor markedly reduced: the degree of pancreas and lung injury; upregulation/expression of ICAM-1; staining for iNOS, nitrotyrosine and PARS; and lipid peroxidation. Additionally, calpain I inhibitor treatment significantly prevented the activation of NF-kappaB as suggested by the inhibition of IkappaB-alpha; degradation in the pancreas tissues after cerulein administration.. Taken together, our results clearly demonstrate that prevention of the activation of NF-kappaB by calpain I inhibitor ameliorates experimental murine acute pancreatitis.

Topics: Acute Disease; Analysis of Variance; Animals; Blotting, Western; Calpain; Ceruletide; Disease Models, Animal; Immunohistochemistry; Intercellular Adhesion Molecule-1; Lipid Peroxidation; Male; Mice; NF-kappa B; Nitric Oxide Synthase; Pancreatitis; Poly(ADP-ribose) Polymerases; Random Allocation; Respiratory Distress Syndrome; Tyrosine