calpain and cariporide

It is well known that tumor necrosis factor-alpha (TNF-alpha) induces hepatocyte apoptosis and contributes to liver diseases. However, the exact mechanisms are not well understood.. In the present study, we reported that Na(+)/H(+) exchanger (NHE) is involved in TNF-alpha-induced hepatocyte apoptosis.. TNF-alpha time dependently induced an increase in NHE activity in hepatocytes, but cariporide, an NHE inhibitor, blocked the TNF-alpha-induced increase of NHE activity in a dose-dependent manner. Increased NHE activity induced by TNF-alpha was associated with increased intracellular calcium (Ca(2+)(i)) concentration and calpain activity. Cariporide reversed these effects induced by TNF-alpha. In addition, TNF-alpha downregulated Bcl-xL, an anti-apoptotic protein, but not mRNA levels. The inhibition of either calpain or NHE blocked the TNF-alpha-induced decrease of the Bcl-xL protein. TNF-alpha did not change the pro-apoptotic Bax and Bak protein levels. Cariporide, calcium remover 1,2-bis (2-aminophenoxy) ethane-N,N,N0,N0-tetraacetic acid, or calpain inhibitor benzyloxycarbonyl-leucyl-leucinal attenuated TNF-alpha-induced hepatocyte apoptosis.. TNF-alpha via NHE results in hepatocyte apoptosis through the calcium/calpain/Bcl-xL pathway.

Topics: Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Calcium; Calpain; Cells, Cultured; Chelating Agents; Cysteine Proteinase Inhibitors; Dipeptides; Dose-Response Relationship, Drug; Egtazic Acid; Guanidines; Hepatocytes; Humans; Signal Transduction; Sodium-Hydrogen Exchangers; Sulfones; Time Factors; Tumor Necrosis Factor-alpha

Recent studies have reported that the calcium-dependent protease calpain is involved in hyperglycaemia-induced endothelial dysfunction and that the Na(+)/H(+) exchanger (NHE) is responsible for an increase in the intracellular calcium (Ca(2+)(i)) concentration in diabetes. We hypothesized that activation of NHE mediates hyperglycaemia-induced endothelial dysfunction via calcium-dependent calpain.. Exposure of human umbilical vein endothelial cells (HUVECs) to high glucose (HG, 30 mM d-glucose) time dependently increased both the Ca(2+)(i) concentration and calpain activity. Chelation of free Ca(2+)(i) with 1,2-bis (2-aminophenoxy) ethane-N, N, N',N'-tetraacetic acid abolished the HG-increased calpain activity. In addition, HG activated NHE in a time-dependent manner, but cariporide, an NHE inhibitor, blocked the HG-induced increase in NHE activity. Furthermore, cariporide or NHE siRNA (small interfering ribonucleic acid) attenuated the HG-induced increases of both Ca(2+)(i) concentration and calpain activity. All of these HG-induced effects in HUVECs, including decreased endothelial nitric oxide synthase (eNOS) activity and NO (nitric oxide) production and increased dissociation of heat shock protein (hsp90) from eNOS, were NHE or calpain reversible. In vivo experiments showed that cariporide treatment via inhibition of NHE activity significantly attenuated the hyperglycaemia-induced impairment of acetylcholine-induced endothelium-dependent relaxation in streptozotocin-injected diabetic rats.. Activation of NHE via calcium-dependent calpain contributes to hyperglycaemia-induced endothelial dysfunction through dissociation of hsp90 from eNOS.

Topics: Animals; Calcium; Calpain; Cells, Cultured; Chelating Agents; Cysteine Proteinase Inhibitors; Diabetes Mellitus, Experimental; Dose-Response Relationship, Drug; Endothelium, Vascular; Glucose; Guanidines; HSP90 Heat-Shock Proteins; Humans; Hyperglycemia; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; RNA Interference; RNA, Small Interfering; Sodium-Hydrogen Exchangers; Sulfones; Time Factors; Vasodilation; Vasodilator Agents

The calpain inhibitor A-705253 and the Na(+)/H(+)-exchange inhibitor Cariporide were studied in isolated perfused rabbit hearts subjected to 60 min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid solely or in combination at the beginning of reperfusion. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were performed. Myocardial infarct size and area at risk (transiently not perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 72.7+/-4.0% of the area at risk in untreated controls, but was significantly smaller in the presence of the inhibitors. The largest effect was seen with 10(-6) m A-705253, which reduced the infarcted area to 49.2+/-4.1% of the area at risk, corresponding to a reduction of 33.6%. Cariporide at 10(-6) m reduced the infarct size to the same extent. The combination of both inhibitors, however, did not further improve cardioprotection. No statistical difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, heart rate, and in the release of lactate dehydrogenase and creatin kinase from heart muscle.

Topics: Animals; Anti-Arrhythmia Agents; Benzamides; Blood Pressure; Calpain; Coronary Circulation; Female; Guanidines; Heart; Heart Rate; In Vitro Techniques; Male; Myocardial Infarction; Myocardium; Potassium; Rabbits; Sodium-Hydrogen Exchangers; Sulfones; Ventricular Function, Left

To investigate the protective effect of calcium antagonists (A/R) injury of cardiomyocytes.. Primary-cultured cardiomyocytes were divided A/R, A/R+nicardipine(Nic), A/R+HOE642, A/R+H7, A/R+PD98059 and control parameters were measured in all groups, intracellular calcium concentration ([Ca2+]i), content, lactate dehydrogenase (LDH) and creative phosphokinase(CK) activity in the activity. The calpain (u-calpain and m-calpain) protein expression levels were measured In comparison with A/R group, A/R + nicardipine (Nic) and A/R + Nic groups showed [Ca2+]i, m-calpain protein expression, LDH and CK content in the medium, a higher activity of PKC and MAPK (P < 0.01). On the contrary, A/R+H7 and A/R+PD98059 LDH and CK content in the medium, and lower ATP content and cell viability as compared 0. 05).. The A/R mediated Ca2+ overload resulting from cardiomyocyte injury blocking Ca2+ entry and H+/Na+ exchange, and very likely PKC and MAPK are involved protection against the A/R injury of cardiomyocytes.

Topics: Animals; Animals, Newborn; Anti-Arrhythmia Agents; Calpain; Cell Hypoxia; Cells, Cultured; Guanidines; Myocardial Reperfusion Injury; Myocytes, Cardiac; Rats; Rats, Wistar; Sulfones