TLR2 and TLR4 are expressed primarily in microglia, even though expression of both receptors in neurons and astrocytes has been reported.33 Our qRT-PCR data revealed distinct temporal expression profiles of these PRRs (Determine 4). a possible molecular mechanism controlling the microglial activation and ensuing responses induced by clustering of distributing depolarization/depressive disorder in stroke and hemiplegic migraine. Materials and methods Experimental animals Adult male C57BL/6 mice (CLEA Japan Inc., transcripts were quantified by the Ct method using glyceraldehyde-3-phosphate dehydrogenase (expression was significantly enhanced irrespective of the number of CSD inductions, the expression level of was significantly upregulated only after five CSD inductions. Treatment with the anti-HMGB1 antibody prior to five CSD inductions attenuated upregulation, whereas there was no significant switch in the expression of and were significantly enhanced regardless of the quantity of CSD inductions (Physique 4, Supplementary Material Table 2). In the mean time, the transcript was not detectable in any group (data not shown). Open in a separate window Physique 4. The effects of single and multiple CSDs around the expression levels of (a), (b), (c), and (d) as assessed by qRT-PCR (normalized to expression). Values are offered as mean??SD. Statistical analysis was carried out by ANOVA and Bonferronis post hoc test. Effect of CSD on the number and morphology of microglia in TLR2/4-deficient mice To examine the involvement of TLR2 and TLR4 in CSD-induced morphological microglial hypertrophy, we induced multiple CSDs in TLR2/4 double knockout mice. First, we confirmed that there was no difference in the basal density and morphological features of microglia between the wild-type and TLR2/4 double knockout mice. In the TLR2/4 knockout mice, there was no significant switch in the total quantity of Iba1-positive CZC-8004 microglia following CSD (KO-control: 96.6??17.0/mm2, KO-CSD5x-24?h: 96.0??12.6/mm2), enlarged microglia after CSD (KO-control: 16.5??15.0/mm2, KO-CSD5x-24?h: 26.3??11.7/mm2), or the proportion of microglial somal area to the entire tissue area (Physique 5). Open in a separate window Physique 5. (a) Representative immunostaining for Iba1 and nuclear counterstaining in the KO mouse cerebral cortex. Bar: 10?m. The numbers of total (b) and enlarged (c) Iba1-positive microglia in Fam162a the cerebral cortex of the wild-type and KO mice in the control and CSD5x-24?h groups. (d) The proportion of microglial somal area to the entire brain tissue area. Values are expressed as mean??SD. Statistical analysis was carried out by ANOVA and Bonferronis post hoc test. Conversation Multiple CSD episodes induced microglial hypertrophy, a sign of activation, which was most prominent 24?h after CSD. Concurrently, the expression levels of CZC-8004 and transcripts were elevated. The importance of TLR2 and TLR4 for CSD-induced microglial activation was substantiated by its attenuation in TLR2/4-deficient mice. Moreover, our pharmacological studies indicate that HMGB1, an important ligand of both TLR2 and TLR4, plays a crucial role in inducing these morphological alterations. Collectively, this is the first demonstration that this HMGB1-TLR2/4 axis mediates microglial activation by multiple CSD episodes. CSD is usually widely believed to be the neurobiological correlate of migraine aura.3 In addition, CSD-like spreading depolarizations are observed in brain tissue exposed to ischemia, hypoxia, or subarachnoid hemorrhage, CZC-8004 and the occurrence of spreading depolarizations in the peri-infarct area likely contributes to the expansion of infarct size by imposing a bioenergetic burden on vulnerable tissue.7,25 Migraine aura is clinically characterized by a short-lasting neurological symptom, CZC-8004 often a gradually expanding visual field defect accompanied by the appearance of the fortification spectrum.1 The duration.