Plos One
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The pathophysiological mechanisms underlying mild traumatic brain injury (mTBI) are not well understood, but likely involve neuroinflammation. Here the controlled cortical impact model of mTBI in rats was used to test this hypothesis. Mild TBI caused a rapid (within 6 h post-mTBI) upregulation of synthesis of TNF-α and IL-1β in the cerebral cortex and hippocampus, followed by an increase in production of neutrophil (CXCL1-3) and monocyte (CCL2) chemoattractants. ⋯ The monocyte influx was not observed until 24 h post-mTBI, and these inflammatory cells predominantly entered the ipsilateral SAS and CVI, with a limited invasion of brain parenchyma. These observations indicate that the endothelium of pial microvessels responds to injury differently than that of intraparenchymal microvessels, which may be associated with the lack of astrocytic ensheathment of cerebrovascular endothelium in pial microvessels. These findings also suggest that neuroinflammation represents the potential therapeutic target in mTBI.
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Conserved protein antigens among serotypes of group A Streptococcus pyogenes (GAS) have been focused for vaccine development because of the diversity of GAS serotypes and risks of autoimmunity post-GAS infection. Precise delineation of protective immune response to each of GAS antigens is critical for vaccine efficacy and safety. We recently reported that immunization with SrtA of GAS provides Th17-dependent clearance of heterologous serotypes of GAS in NALT. ⋯ The co-immunization induced Th17 and robust SCPA antibody responses, accompanied by a rapid influx of neutrophils and high myeloperoxidase activity in NALT, suggesting that simultaneous induction of mucosal Th17 and neutralizing antibody responses offers more effective GAS elimination through rapid infiltration and activation of neutrophils. Moreover, Th17 response was strongly induced in mice that experienced repeated GAS-infection and maintained at a high level even after the bacteria were cleared; whereas, it was moderately induced and promptly returned to baseline following bacterial elimination in SrtA/SCPA co-immunized mice. Additional results showed that the survival rate of systemic challenge was significantly higher in infection experienced than in co-immunized mice, indicating that more immune elements are required for protection against systemic than mucosal GAS infection.
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Mechanical ventilation is a life-saving procedure for patients with acute respiratory failure, although it may cause pulmonary vascular inflammation and leakage, leading to ventilator-induced lung injury (VILI). Ly6C+high monocytes are involved in the pathogenesis of VILI. In this study, we investigated whether pulmonary infiltrated Ly6C+high monocytes produce vascular endothelial growth factor (VEGF) and contribute to VILI. ⋯ VEGF produced by pulmonary infiltrated Ly6C+high monocytes regulates vasculature permeability in a two-hit model of HTV-induced lung injury. Ly6C+high monocytes play an important role in the pathogenesis of VILI.
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Chronic pain is a long-lasting debilitating condition that is particularly difficult to treat due to the lack of identified underlying mechanisms. Although several key contributing processes have been described at the level of the spinal cord, very few studies have investigated the supraspinal mechanisms underlying chronic pain. Using a combination of approaches (cortical intrinsic imaging, immunohistochemical and behavioural analysis), our study aimed to decipher the nature of functional and structural changes in a mouse model of orofacial neuropathic pain, focusing on cortical areas involved in various pain components. ⋯ This reduced functional activation is likely due to the increased basal neuronal activity (measured indirectly using cFos and phospho-ERK immunoreactivity) observed in several cortical areas, including the contralateral barrel field, motor and cingulate cortices. In the same animals, immunohistochemical analysis of markers for active pre- or postsynaptic elements (Piccolo and phospho-Cofilin, respectively) revealed an increased immunofluorescence in deep cortical layers of the contralateral barrel field, motor and cingulate cortices. These results suggest that long-lasting orofacial neuropathic pain is associated with exacerbated neuronal activity and synaptic plasticity at the cortical level.
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Inflammatory M1 spectrum macrophages protect from infection but can cause inflammatory disease and tissue damage, whereas alternatively activated/M2 spectrum macrophages reduce inflammation and promote tissue repair. Modulation of macrophage phenotype may be therapeutically beneficial and requires further understanding of the molecular programs that control macrophage differentiation. A potential mechanism by which macrophages differentiate may be through microRNA (miRNA), which bind to messenger RNA and post-transcriptionally modify gene expression, cell phenotype and function. ⋯ Comparative transcriptional profiling of unstimulated and M1(LPS + IFN-γ) macrophages derived from wild-type (WT) and miR-155 knockout (KO) mice revealed that half (approximately 650 genes) of the signature we previously identified in WT M1(LPS + IFN-γ) macrophages was dependent on miR-155. Real-Time PCR of independent datasets confirmed that miR-155 contributed to suppression of its validated mRNA targets Inpp5d, Tspan14, Ptprj and Mafb and induction of Inos, Il1b, Tnfa, Il6 and Il12. Overall, these data indicate that miR-155 plays an essential role in driving the inflammatory phenotype of M1(LPS+ IFN-γ) macrophages.