Plos One
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Recent studies have shown that histones, the chief protein component of chromatin, are released into the extracellular space during sepsis, trauma, and ischemia-reperfusion injury, and act as major mediators of the death of an organism. This study was designed to elucidate the cellular and molecular basis of histone-induced lethality and to assess the protective effects of recombinant thrombomodulin (rTM). rTM has been approved for the treatment of disseminated intravascular coagulation (DIC) in Japan, and is currently undergoing a phase III clinical trial in the United States. ⋯ Extracellular histones cause massive thromboembolism associated with consumptive coagulopathy, which is diagnostically indistinguishable from DIC. rTM binds to histones and neutralizes the prothrombotic action of histones. This may contribute to the effectiveness of rTM against DIC.
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Lipopolysaccharide (LPS) in high doses inhibits placental multidrug resistance P-glycoprotein (P-gp--Abcb1a/b) and breast cancer resistance protein (BCRP--Abcg2). This potentially impairs fetal protection against harmful factors in the maternal circulation. However, it is unknown whether LPS exposure, at doses that mimic sub-lethal clinical infection, alters placental multidrug resistance. ⋯ Acute infection decreased placental P-gp activity in a time- and gestational age-dependent manner. Chronic LPS decreased P-gp activity in the maternal myocardium and there was a trend for fetuses with smaller placentas to accumulate more P-gp substrate than their larger counterparts. Collectively, we demonstrate that acute sub-lethal LPS exposure during pregnancy impairs fetal protection against potentially harmful xenobiotics in the maternal circulation.
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The levels of circulating microRNAs (miRNAs) in mice with experimental sepsis induced by cecal ligation and puncture (CLP) were determined using whole blood samples obtained from C57BL/6 mice at 4, 8, and 24 h after CLP; miRNA expression analysis was performed in these samples using an miRNA array. Microarray analysis revealed upregulation of 10 miRNA targets (miR-16, miR-17, miR-20a, miR-20b, miR-26a, miR-26b, miR-106a, miR-106b, miR-195, and miR-451). ⋯ Immunoprecipitation with the Argonaute 2 ribonucleoprotein complex revealed significantly increased expression of the 10 miRNA targets in the serum of mice after CLP, and the levels of 6 (miR-16, miR-17, miR-20a, miR-20b, miR-26a, and miR-26b) of these 10 miRNA targets increased significantly in exosomes isolated using ExoQuick precipitation solution. In this study, we identified circulating miRNAs that were up-regulated after CLP and determined the increase in the levels of these miRNAs, and our results suggest that circulating Ago2 complexes and exosomes may be responsible for the stability of miRNAs in the serum.
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The mechanism(s) by which cells can sense exogenous oxidants that may contribute to intracellular oxidative/nitrosative stress is not clear. The objective of this study was to determine how cells might respond to exogenous oxidants to potentially initiate, propagate and/or maintain inflammation associated with many human diseases through NF-κB activation. First, we used HEK-Blue cells that are stably transfected with mouse toll-like receptor 4 (mTLR4) or mouse TLR2. ⋯ Furthermore, a novel pro-oxidant that decays to produce the same reactants as activated phagocytes induced inflammatory pain responses in the mouse orofacial region with increased TLR4 expression, and IL-1β and TNFα tissue levels. EUK-134, a synthetic serum-stable scavenger of oxidative species decreased these effects. Our data provide in vitro and related in vivo evidence that exogenous oxidants can induce and maintain inflammation by acting mainly through a TLR4-dependent pathway, with implications in many chronic human ailments.
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Repair in multiple sclerosis involves remyelination, a process in which axons are provided with a new myelin sheath by new oligodendrocytes. Bone morphogenic proteins (BMPs) are a family of growth factors that have been shown to influence the response of oligodendrocyte progenitor cells (OPCs) in vivo during demyelination and remyelination in the adult brain. We have previously shown that BMP4 infusion increases numbers of OPCs during cuprizone-induced demyelination, while infusion of Noggin, an endogenous antagonist of BMP4 increases numbers of mature oligodendrocytes and remyelinated axons following recovery. ⋯ Furthermore, electron microscopy analysis revealed no change in average myelin thickness in the corpus callosum between vehicle infused and BMP4-Noggin infused mice. Our results suggest that while single delivery of Noggin or IGF-1 increased the production of mature oligodendrocytes in vivo in the context of demyelination, only Noggin infusion promoted remyelination. Thus, sequential delivery of BMP4 and Noggin or IGF-1 does not further enhance myelin repair above what occurs with delivery of Noggin alone.