Reduction of microglial activity in a model of multiple sclerosis by dipyridamole

BACKGROUND: Despite extensive and persistent activation of microglia in multiple sclerosis (MS), microglia inhibitors have not yet been identified for treatment of the disorder. We sought to identify medications already in clinical use that could inhibit the activation of microglia. On the basis of the reported inhibitory effects of dipyridamole on phosphodiesterase activity that result in the production of various anti-inflammatory outcomes, we selected it for study. Dipyridamole is used clinically for secondary prevention in stroke. In this study, dipyridamole was examined using microglia in culture and in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). RESULTS: We found that dipyridamole attenuated the elevation of several cytokines and chemokines in human microglia caused by Toll-like receptor stimulation. Morphological characteristics of activated microglia in culture were also normalized by dipyridamole. In mice, dipyridamole decreased the clinical severity of EAE and reduced microglial activity and other histological indices of EAE in the spinal cord. CONCLUSIONS: Dipyridamole is an inhibitor of microglia activation and may have a role in MS and other neurological conditions to attenuate microglial activity

Activation of Src protein tyrosine kinase plays an essential role in urocortin-mediated cardioprotection

Urocortin is a 40 amino acid peptide of the corticotrophin-releasing factor (CRF) family that is synthesized and released by cardiac myocytes. Endogenous urocortin expression is increased during ischemia/reperfusion (I/R) and addition of exogenous urocortin reduces cell death caused by I/R injury. Studies have also showed that the protective action of urocortin is mediated by the activation of ERK1/2. We discovered that a non-receptor tyrosine kinase, Src, is involved in the urocortin-induced activation of ERK1/2 in mouse atrial HL-1 myocytes. The selective Src family kinase inhibitor, PP2, reduced the urocortin-induced phosphorylation of ERK1/2, and so did the expression of a dominant-negative mutant of Src in transfected HL-1 cells. Inhibition of Src by PP2 also reduced urocortin's protective effects in HL-1 cells after hypoxia/reoxygenation (H/R), as assessed by flow cytometry and caspase-3 activation assay. Titration studies indicated that as little as 10 128 M urocortin was sufficient to induce Src activation. Maximal phosphorylation/activation of Src and ERK1/2 were both detected after 5 min incubation with urocortin. These effects of urocortin were largely mediated by CRF receptor-1, although a minor contribution of CRF receptor-2 cannot be excluded. Here we report for the first time that short-term treatment with urocortin causes rapid phosphorylation of Src, and that the urocortin-activated Src kinase serves as an upstream modulator of ERK1/2 activation, playing an essential role in urocortin-mediated cardioprotection

The role of minocycline in ischemia-reperfusion injury: a comprehensive review of an old drug with new implications.

Minocycline is a semi-synthetic tetracycline that inhibits bacterial protein synthesis and hence is used for the treatment of many infectious diseases. Over the years, many other interesting properties of minocycline have been identified and been used to make patents which include anti-inflammatory, anti-apoptotic, matrix metalloproteinase inhibitor and free oxygen radical scavenger activity. Ischemia-reperfusion injury is a concern for almost every clinical specialty and minocycline seems to be an attractive cytoprotective agent that can ameliorate the damage due to these properties. Ischemia-reperfusion injury is a complex process and involves various pathways that lead to cell death. This review focuses on the body of evidence describing various proposed mechanisms of action of minocycline and its current experimental use in various animal models of ischemia-reperfusion injury