ABSTRACT
Ischemic injury in the heart is associated with death of cardiomyocytes and even after decades of research there is no appropriate therapeutic intervention to treat ischemic injury. The microRNA miR-34a is known to be induced in cardiomyocytes following ischemic injury. Another hallmark of ischemic injury is impaired glycolysis. The objective of the current study was to investigate the effects of short- and long-term exposure to hypoxia on miR-34a expression on apoptosis and regulation of key glycolysis metabolic enzymes. Both repeated short-term (30 min) burst of hypoxia with intermittent reoxygenation (30 min) as well as long-term (4 h) exposure to hypoxia followed by 6 h of reoxygenation robustly induced miR-34a levels. Hypoxia induced changes in cardiac permeability and localization of the channel protein connexin 34 as well as induced apoptosis as evident by levels of cleaved-caspase 3/7 and impaired cell proliferation. Hypoxia was also associated with decreased expression of key glycolytic enzymes hexokinase-1, hexokinase-2, glucose-6-phosphate-isomerase, and pyruvate dehydrogenase kinase 1. Attenuation of hypoxia-induced miR-34a by anti-miR-34a antagomir, but not a control antagomir, decreased miR-34a levels to those observed under normoxia and also inhibited apoptosis, potentially by rescuing expression of the key glycolytic enzymes. Cumulatively, our results establish that therapeutic targeting of miR-34a via antagomir might be a potent therapeutic mechanism to treat ischemic injury in the heart.
Subject(s)
Antagomirs/pharmacology , Cardiotonic Agents/pharmacology , Glucose/metabolism , Hypoxia/genetics , MicroRNAs/genetics , Myocytes, Cardiac/metabolism , Animals , Apoptosis/drug effects , Cell Hypoxia/drug effects , Cells, Cultured , Down-Regulation/drug effects , Hypoxia/drug therapy , Hypoxia/metabolism , Male , Myocytes, Cardiac/cytology , Myocytes, Cardiac/drug effects , Rats, Wistar , Up-Regulation/drug effectsABSTRACT
Patchouli alcohol (PA) is a tricyclic sesquiterpene extracted from a traditional Chinese herb pogostemonis herba. Literatures have proven that PA could inhibit inflammatory responses in various inflammatory disease models. However, whether PA could protect against atherosclerosis, a chronic vascular inflammation, is unknown. In this study, we sought to explore this issue in atherosclerosis-prone apolipoprotein E knockout mice fed an atherogenic diet, with or without daily PA intragastrical administration (40mg/kg). Our results showed that PA administration did not change plasma lipids metabolism, however, it significantly attenuated atherosclerotic plaque burdens in both the aorta and the aortic root. The lesional macrophage content, shown as Mac2 positive areas, was reduced, while the lesional smooth muscle cell and collagen content, shown as α-SMA positive areas and by Sirius red staining, respectively, was not affected in PA-treated mice, compared with non-treated controls. Aortic mRNA expression of macrophage inflammatory cytokines, including MCP-1, iNOS, IL-1ß, IL-6, CXCL9 and CXCL11, was also reduced in PA-treated mice. Therefore, we demonstrated that PA could attenuate atherosclerosis, possibly by inhibiting macrophage infiltration and its inflammatory responses.
Subject(s)
Atherosclerosis/drug therapy , Inflammation/pathology , Macrophages/pathology , Sesquiterpenes/therapeutic use , Animals , Aorta/drug effects , Aorta/pathology , Apolipoproteins E/deficiency , Apolipoproteins E/metabolism , Atherosclerosis/blood , Atherosclerosis/genetics , Atherosclerosis/pathology , Gene Expression Regulation/drug effects , Inflammation/genetics , Lipid Metabolism/drug effects , Lipid Metabolism/genetics , Lipids/blood , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Knockout , Plaque, Atherosclerotic/pathology , Sesquiterpenes/pharmacologyABSTRACT
The calcitonin receptor-like receptor (CRLR) and the orphan receptor RDC-1 have been proposed to be calcitonin gene-related peptide type 1 (CGRP1) receptors, and receptor activity-modifying proteins (RAMPs) determine the ligand specificity of CRLR. Coexpression of RAMP1 and CRLR resulted in functional CGRP1 receptors; the complex of RAMP2 or RAMP3 and CRLR created functional adrenomedullin receptor. Although high levels of CGRP binding sites in the nucleus accumbens have been reported, little is known about the expression of these novel CGRP receptors. In the present study, we used real-time quantitative RT-PCR to detect and quantitate the relative expression of CGRP, CRLR, RAMP1-3 and RDC-1 in the nucleus accumbens of intact rats and rats with inflammation. Our results demonstrate that CGRP, CRLR, RAMP1 and RAMP2 exist in the nucleus accumbens of intact rats, and that they were significantly upregulated in rats with inflammation. In contrast, no expression was detected for RDC-1 and RAMP3. These findings indicated a functional role for CGRP and its receptors in inflammation and pain modulation.
