Changes in IP3 receptor expression and function in aortic smooth muscle of atherosclerotic mice

Peroxynitrite is an endothelium - independent vasodilator which induces relaxation via membrane hyperpolarisation. A ctivation of IP3 receptors triggers opening of potassium channels and hyperpolarisation. Previously we found that relaxation to peroxynitrite was maintained during development of atherosclerosis due to changes in expression of calcium regulatory proteins. In this study we investigated 1) the mechanism of peroxynitrite - induced relaxation in mouse aorta 2) the effect of atherosclerosis on relaxation to peroxynitrite and other vasodilators 3) the effect of atherosclerosis on expression and function of the IP3 receptor. Aortic function was studied using wire myography and atherosclerosis was induced by fat - feeding ApoE - / - mice . Expression of IP3 receptors was studied using Western blotting and immunohistochemistry . Relaxation to peroxynitrite was attenuated by the IP3 antagonists 2 - APB and xestospongin C and also the Kv channel blocker 4 - AP. Atherosclerosis attenuated vasodilation to cromakalim and the AMPK activator A769662 but not peroxynitrite. Relaxation was attenuated to a greater extent by 2 - APB in atherosclerotic aortae despite reduced expression of IP3 receptors. 4 - AP was less effective in 4 month fat fed ApoE - / - mice. Peroxynitrite relaxation involves IP3 - induced calcium release and K V channel activation. This mechanism becomes less important as atherosclerosis develops and relaxation to peroxynitrite may be maintained by increased calcium extrusion

Evaluating the Antimicrobial and Anti-Hemolytic Activity of Synthesized Pseudopeptide against <i>Leptospiral</i> Species: In Silico and In Vitro Approach

Bacterial infections are one of the leading causes of morbidity, mortality, and healthcare complications in patients. Leptospirosis is found to be the most prevalent, re-emergent, and neglected tropical zoonotic disease worldwide. The adaptation to various environmental conditions has made Leptospira acquire a large genome (~4.6 Mb) and a complex outer membrane, making it unique among bacteria that mimic the symptoms of jaundice and hemorrhage. Sph2 is another important virulence factor that enhances hemolytic sphingomyelinase—capable of moving inside mitochondria—which increases the ROS level and decreases the mitochondrial membrane potential, thereby leading to cell apoptosis. In the present study, 25 suspected bovine serum samples were subjected to the Microscopic Agglutination Test (MAT) across the Mysuru region. Different samples, such as urine, serum, and aborted materials from the confirmed MAT-positive animals, were used for isolation and genomic detection by conventional PCR targeting virulence gene, Lipl32, using specific primers. Further, in vitro and in silico studies were performed on isolated cultures to assess the anti-leptospiral, anti-hemolytic, and sphingomyelinase enzyme inhibition using novel pseudopeptides. The microdilution technique (MDT) and dark field microscope (DFM) assays revealed that at a concentration of 62.5 μg/mL, the pseudopeptide inhibited 100% of the growth of Leptospira spp., suggesting its efficiency in the treatment of leptospirosis. The flow cytometry analyses show the potency of the pseudopeptide against sphingomyelinase enzymes using human umbilical vein endothelial cells (HUVECs). Thus, the present study demonstrated the efficacy of the pseudopeptide in the inhibition of the growth of Leptospira, and therefore, this can be used as an alternative drug for the treatment of leptospirosis