IL‐17A synergistically enhances TLR3‐mediated IL‐36γ production by keratinocytes: A potential role in injury‐amplified psoriatic inflammation

Skin injury can trigger formation of new lesions in psoriasis (Koebner phenomenon). The mechanisms through which injury exacerbates psoriasis are unclear. During wound repair, epidermal keratinocytes are activated and produce abundant IL‐36γ, further promoting the skin inflammation. IL‐17A is the cornerstone cytokine in the pathogenesis of psoriasis. We sought to investigate the effects of IL‐17A on injury‐induced keratinocyte activation and IL‐36γ production. Here, we demonstrated that dsRNA released from necrotic keratinocytes induced the expression of IL‐36γ. Silencing of TLR3 by siRNA decreased the IL‐36γ induction by necrotic keratinocyte supernatant. Co‐stimulation with dsRNA and IL‐17A synergistically increased the expression of IL‐36γ and other proinflammatory mediators (CCL20, CXCL8, DEFB4 and LCN2) in keratinocytes. The synergistic effects were not dependent on TLR3 upregulation, TNF receptor signalling and mRNA stabilization. Co‐stimulation with dsRNA and IL‐17A resulted in an accumulation of IκBζ. The synergistic upregulation of IL‐36γ and proinflammatory mediators were inhibited by IκBζ siRNA. Co‐stimulation with IL‐17A and poly(I:C) markedly activated the p38 MAPK and NF‐κB pathway, compared with poly(I:C). Blockade of p38 MAPK and NF‐κB suppressed dsRNA/IL‐17A–mediated IκBζ and IL‐36γ induction. These findings demonstrated that IL‐17A synergistically enhanced the dsRNA‐mediated IL‐36γ production through a p38 MAPK‐, NF‐κB–, and IκBζ‐dependent mechanism.     

SDF-1α/CXCR4 信号通路在轴向应力刺激促进骨再生中的作用研究

目的通过轴向应力刺激促进骨再生，观察基质细胞衍生因子 1α/趋化因子 CXC 亚族受体 4（stromal cell-derived factor 1α/cysteine X cysteine receptor 4，SDF-1α/CXCR4）信号通路变化，探讨轴向应力刺激促进骨再生的机制。方法取 72 只雄性新西兰大白兔，于右后肢胫骨近端内侧制备直径 8 mm 圆形皮质骨缺损并脱蛋白松质骨支架修复模型，随机分为 3 组（n=24）。A 组腹腔注射 PBS，B 组术肢给予应力刺激治疗+腹腔注射 PBS，C 组术肢给予应力刺激治疗+腹腔注射 CXCR4 拮抗剂（AMD3100）。术后 2、4、8、12 周，摄 X 线片并采用 Lane-Sandhu X 线评分标准评价骨愈合情况，取标本行 HE 染色观察新生骨组织及支架降解，免疫组织化学染色观察 VEGF、CXCR4 表达水平；4、8 周取标本 Western blot 检测 SDF-1α 及 CXCR4 蛋白表达水平；12 周行 Micro-CT 检查，计算新生骨体积及新生骨密度。 结果X 线片检查示，除术后 2 周各组骨缺损区及支架无明显变化外，4、8 及 12 周时 B 组骨愈合评分均高于 A、C 组（P<0.05）。12 周时 Micro-CT 扫描可见 B 组骨缺损修复、髓腔再通，新生骨体积及骨密度均高于 A、C 组（P<0.05）。HE 染色显示，术后 4 周开始 B 组骨再生及支架降解均明显快于 A、C 组。免疫组织化学染色示，各组 VEGF 及 CXCR4 阳性表达均在 4 周达峰值；各时间点 B 组 VEGF 及 CXCR4 表达量均显著高于 A、C 组（P<0.05）。Western blot 检测显示，4、8 周时 B 组 SDF-1α 与 CXCR4 表达量均显著高于 A、C 组（P<0.05）。 结论轴向应力刺激促进骨再生可能与其促进骨缺损区组织高表达 SDF-1α，激活与其下游调控 BMSCs 募集的 CXCR4 信号有关。     

The value of mRNA expression of S100A8 and S100A9 as blood-based biomarkers of inflammatory bowel disease

Background and study aimsNon-invasive biomarkers of inflammatory bowel diseases (IBD) are of critical importance. Here, we evaluated the S100A8 and S100A9 mRNA expression, as the heterodimers of calprotectin, in the blood leucocytes of IBD patients to find how their expression associates with the disease characteristics.Patients and methodsIn this cross-sectional study, 59 IBD patients and 30 healthy subjects were included. The flare and remission phases of disease were identified in 46 and 13 patients, respectively. Blood leucocytes were isolated, and the S100A8 and S100A9 mRNA expression were evaluated in the isolated leucocytes using relative quantification real-time PCR.ResultsThe mean S100A8 and S100A9 mRNA expression were significantly higher in IBD patients than in the controls (p = 0.03 and p = 0.02, respectively). The mean S100A8 and S100A9 mRNA expression were significantly higher in the flare phase of the disease compared with the remission phase (p = 0.01 and p = 0.007, respectively). S100A8 distinguished IBD patients from controls with the sensitivity and specificity of 73% and 64%, and flare phase of disease from remission with the sensitivity and specificity of 67% and 62%. On the other hand, S100A9 distinguished IBD patients from controls with the sensitivity and specificity of 81% and 70%, and flare phase of disease from remission with the sensitivity and specificity of 68% and 64%.ConclusionThe S100A8 and S100A9 mRNA are differentially expressed in blood leucocytes of IBD patients compared to healthy controls as well as active versus quiescent disease. Thus, they can be potentially used as a blood-based biomarker in the monitoring of IBD.     

A Positive Feedback Loop Between Th17 Cells and Dendritic Cells in Patients with Endplate Inflammation

Background: Endplate inflammation remains a difficult disease to treat, in part due to its unclear pathology. Previous experiments showed that patients with idiopathic inflammation presented a systemic upregulation of Th17 cells. Here, we investigated how this change might affect the inflammatory environment in endplate inflammation.

Methods: Peripheral blood was obtained from patients and healthy controls, and Th17 cells were examined.Results: Th17 cells significantly increased the differentiation of CD11c+ and DC-SIGN+ dendritic cells (DCs) from circulating monocytes in the absence of exogenous stimulation as well as in the presence of LPS stimulation. Th17 cells also increased CD80 and CD86 expression by DCs. Importantly, although Th17 cells from both healthy controls and patients with endplate inflammation could induce CD11c, DC-SIGN, CD80, and CD86 expression, Th17 cells from patients with endplate inflammation showed significantly more potent capacity. Both contact-dependent and IL-17-dependent mechanisms were employed by Th17 cells, since blocking cell-to-cell contact significantly inhibited Th17-mediated differentiation of CD11c+ DCs, and neutralization of IL-17 reduced the expression of CD80 and CD86. Strikingly, DCs following incubation with Th17 cells, but not the DCs derived directly from monocytes without Th17 cells, could significantly promote the expression of IL-17 from naive CD4+ T cells.

Conclusions: These results demonstrated that Th17 cells from patients with endplate inflammation could potently induce the differentiation and activation of DCs that preferentially promoted IL-17 response in a positive feedback loop.     

Serum TLR2 and TLR4 levels in colorectal cancer and their association with systemic inflammatory markers,tumor characteristics,and disease outcome

Toll‐like receptors (TLRs) are involved in colorectal cancer (CRC) pathogenesis. However, the significance of serum TLR concentrations in CRC is unknown. We analyzed serum TLR2 and TLR4 concentrations with ELISA in preoperative samples from 118 patients with CRC and 88 matched controls. We also assessed tissue TLR expression with immunohistochemistry and by detecting serum determinants of systemic inflammation. Most participants (>70%) had undetectable serum TLR2. The mean serum TLR4 levels were lower in patients than in controls (1.1 vs 1.8 ng/mL; p = 0.015). Undetectable TLR4 was more common in stage I (39%) than in stages II–IV (11%, p < 0.001). TLR2 or TLR4 expression in tumor cells did not correlate with serum levels, but abundant TLR2 expression in normal colon epithelium was associated with detectable serum TLR2 (p = 0.034). Undetectable serum TLR2 was linked to high modified Glasgow prognostic scores (p = 0.010), high CRP levels (p = 0.013), blood vessel invasion (p = 0.013), and tended to be associated with worse 5‐year survival (p = 0.052). In conclusion, serum TLR2 levels were inversely associated with systemic inflammation in patients with CRC. Moreover, serum TLR2 levels might depend more on normal colorectal mucosa contributions than on tumor tissue contributions. Further studies are required to assess the prognostic value of serum TLR2.     

Pannexin 1 channels facilitate communication between T cells to restrict the severity of airway inflammation

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