Macrophages limit inflammatory responses by clearing apoptotic cells. Deficiencies in apoptotic cell phagocytosis have been linked to autoimmunity. In this study, we determined the efficiency with which macrophages from diabetes-prone NOD and diabetes-resistant NOR, Idd5, Balb/c, and C57BL/6 mice phagocytose apoptotic thymocytes and NIT-1 insulinoma cells. Peritoneal and bone marrow-derived macrophages from NOD mice engulfed fewer apoptotic thymocytes than macrophages from Balb/c mice (P < 0.05). Peritoneal macrophages from NOR and Idd5 NOD congenic mice were more proficient at engulfment than their NOD counterparts. Annexin V blockade diminished apoptotic thymocyte clearance and heat-labile serum factors augmented clearance. Binding of apoptotic thymocytes to NOD macrophages was also reduced, suggesting that the deficiency in phagocytosis may be partly attributable to a recognition defect. Peritoneal macrophages from female Balb/c and NOD mice were equally efficient in the engulfment of microspheres, suggesting that the phagocytic deficiency observed in NOD mice was specific for apoptotic cells. In summary, we have demonstrated a deficiency in phagocytic function of macrophages from NOD mice. Normal and diabetes-prone neonatal rodents have a wave of -cell apoptosis coincident with the onset of target organ inflammation. A constitutive defect in the clearance of apoptotic -cells may be contributory to the initiation of autoimmunity. Diabetes
AbstractBackgroundEncephalitis in hand, foot, and mouth disease (HFMD) is a serious threat to children’s health and life. Toll-like receptor 3 (TLR3) is an innate immune-recognition receptor that can recognize virus and initiate innate immune responses. Emodin has the effects of anti-inflammatory and regulating immune function, but the mechanism is not very clear.MethodsCells and mice were pretreated with coxsackievirus B3m (CVB3) and treated with emodin. The messenger ribonucleic acid (mRNA) and protein levels of TLR3 and downstream molecules were detected by quantitative real-time polymearse chain reaction and western blotting analysis, respectively. TLR3 expression was also downregulated by anti-TLR3 antibody (TLR3Ab) or small interfering RNA (siRNA). Pathological changes were assessed with hematoxylin and eosin staining. Immunohistochemistry was used to examine the expression of TLR3 in brain tissues. The expression of interleukin (IL)-6, nuclear factor (NF)-κB, and interferon (IFN)-β in serum were tested with enzyme-linked immunosorbent assay.ResultsEmodin decreased the mRNA and protein levels of TLR3 and downstream molecules in vitro and in vivo. After downregulating TLR3 using anti-TLR3Ab or siRNA, emodin could still decrease the mRNA and protein levels of TLR3 and downstream molecules. Emodin also displayed notable effects on pathology, TLR3 protein in brain tissues, and expression of IL-6, NF-κB, IFN-β, in serum.ConclusionsEmodin exerts a protective effect in CVB3-mediated encephalitis in HFMD by inhibiting the TLR3 pathway.
TIM-4 plays an important role in ischaemia-reperfusion injury of liver and kidney; however, the effects of TIM-4 on cerebral ischaemia-reperfusion injury (IRI) are unknown. The purpose of the present study was to investigate the potential role of TIM-4 in experimental brain ischaemia-reperfusion injury. In this study, cerebral ischaemia reperfusion was induced by transient middle cerebral artery occlusion (MCAO) for 1 hour in C57/BL6 mice. The TIM-4 expression was detected in vivo or vitro by real-time quantitative polymerase chain reaction, Western blot and flow cytometric analysis. In vivo, the administration of anti-TIM-4 antibodies significantly suppressed apoptosis, inhibited inflammatory cells and enhanced anti-inflammatory responses. In vitro, activated microglia exhibited reduced cellular proliferation and induced IRI injury when co-cultured with neurons; these effects were inhibited by anti-TIM-4 antibody treatment. Similarly, microglia transfected with TIM-4 siRNA and stimulated by LPS + IFN-γ alleviated the TIM-4-mediated damage to neurons.Collectively, our data indicate that the inhibition of TIM-4 can improve the inflammatory response and exerts a protective effect in cerebral ischaemia-reperfusion injury.
K E Y W O R D Scerebral ischaemia-reperfusion injury, co-culture, TIM-4
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