Clemastine Fumarate Protects Against Myocardial Ischemia Reperfusion Injury by Activating the TLR4/PI3K/Akt Signaling Pathway

Abstract

Our pilot studies have shown that clemastine fumarate (CLE) can protect against myocardial ischemia-reperfusion injury (MIRI) through regulation of toll like receptor 4 (TLR4). However, the protective mechanism of CLE and related signaling pathways for MIRI remains unclear. The objective of this study is to determine the mechanism by which CLE relieves MIRI in cardiomyocytes and its relationship with the TLR4/PI3K/Akt signaling pathway. CCK8 analysis was used to test the optimal concentration of TLR4 inhibitor CLI-095 and TLR4 agonist lipopolysaccharide (LPS) on MIRI. The expression of inflammatory factors, oxidative stress response, cell damage, and intracellular calcium redistribution of cardiomyocytes were examined using the ELISA kits, Total Superoxide Dismutase Assay Kit with WST-8 and Lipid Peroxidation MDA Assay Kit, LDH Cytotoxicity Assay Kit, and laser scanning confocal microscope. The expression of TLR4/PI3K/Akt and cleaved caspase-3 were determined by Western blotting and immunofluorescent staining. Our results showed that MIRI aggravated the inflammatory response, oxidative stress, cellular damage of cardiomyocytes, and caused redistribution of intracellular calcium, upregulated the expression of TLR4 protein, cleaved caspase-3 protein, and down-regulated the expression of PI3K/Akt protein. After treatment with CLE, the inflammatory response, oxidative stress, and cellular damage of cardiomyocytes were alleviated, and intracellular calcium ion accumulation decreased. The expression of TLR4 protein, cleaved caspase-3 protein declined, but PI3K/Akt protein expression increased in cardiomyocytes treated with CLE. In addition, after treatment with the TLR4 inhibitor CLI-095, the results were similar to those of CLE treatment. The TLR4 agonist LPS aggravated the reactions caused by MIRI. The role of LPS was reversed after CLE treatment. These results suggested that CLE can attenuate MIRI by activating the TLR4/PI3K/Akt signaling pathway.

A novel Danshensu/tetramethylpyrazine protects against Myocardial Ischemia Reperfusion Injury in rats

“…When MIR injury occurs, the expression of pro-inflammatory factors increases, which is mainly due to the increased release of IL-1β and TNF-α 4 , 24 .In order to verify the effect of ADTM on the inflammatory responses following IR injury, the myocardium levels of pro-inflammatory cytokines, including IL-1β and TNF-α, were determined in rats. As shown in Figure 2 D and E, treatment with ADTM (24 mg/kg) significantly reduced the levels of IL-1β and TNF-α as compared with the IR group, indicating that treatment with ADTM might confer its cardio-protective effect by reducing pro-inflammatory cytokines in MIR injury.…”

“…Myocardial ischemia reperfusion (MIR) injury is a main clinical outcome of CHD which is characterized by an initial limitation in blood supply, followed by restoration of perfusion and concomitant re-oxygenation, and ultimately leads to acute myocardial infarction, severe arrhythmias, or heart failure 2 , 3 . The main pathogenesis of MIR is related to the massive release of free oxygen radicals, loss of intracellular and mitochondrial calcium homeostasis, inflammation cascades, promotion of apoptosis and myocardial necrosis 4 . Therefore, to fully understand the mechanism of MIR damage and to find new effective drugs is still the focus of research.…”

DL‑3‑n‑butylphthalide protects H9c2 cardiomyoblasts from ischemia/reperfusion injury by regulating HSP70 expression via PI3K/AKT pathway activation

“…During myocardial ischemia, a large number of oxygen free radicals are produced, eventually leading to the destruction of the mitochondrial structure, mitochondrial swelling, cell membrane structure damage and the disturbance of cell energy metabolism (39). MDA is the final product of reactive oxygen species oxidation of arachidonic acid, representing a biomarker of lipid peroxidation produced by oxidative stress (40).…”

Salvianolic acid B alleviates myocardial ischemic injury by promoting mitophagy and inhibiting activation of the NLRP3 inflammasome

“…As the core target of inflammatory responses, the NLRP3 inflammasome has been considered the key regulator of numerous inflammatory diseases (36). LPS + ATP is a classical activator of the NLRP3 inflammasome; it is widely used in studies of NLRP3 inflammasome-related diseases, including myocardial ischemia (37,38). activation of the classic NLRP3 inflammasome requires two steps: Firstly, microorganisms or other inflammatory factors bind to Toll-like receptor 4 (Tlr4) and activate the Tlr4/nF-κB signaling pathway to induce the expression of nlrP3, pro-caspase-1 and pro-il-1β (priming phase).…”