Background and aims

Inflammatory bowel disease (IBD) are the major risk factor for developing colitis associated cancer (CAC). Previously, we have reported that Phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) was overexpressed in colorectal cancer (CRC), but we don't know the role of PIK3R3 in IBD.

Methods

We investigated the differential expression of PIK3R3 and ZO-1 in IBD patients by using Immunohistochemical (IHC) and Gene Expression Omnibus (GEO) database analysis. Caco-2 cells were exposed to different conditions to assess protein level changes of PIK3R3 and ZO-1. Caco-2 cell monolayers were transfected with PIK3R3/siPIK3R3 to assess transepithelial electrical resistance. Tight junction protein integrity was assessed by immunoblot and immunofluorescence. For further, intestinal permeability and tight junction protein integrity were assessed in animal study to assess the treatment role of PIK3R3 specific inhibitor TAT-N 15 (N15).

Results

PIK3R3 was increased in IBD patients, and negatively controlled the expression of ZO-1. In vitro, PIK3R3 regulates ZO-1 by activating NF-kB pathway. Overexpression of PIK3R3 in Caco-2 cells decreased transepithelial electrical resistance (TEER), an opposite result was observed in siPIK3R3 cells. In animal study, inhibition of PIK3R3 by N15 contributed to amelioration of DSS-induced intestinal permeability. Mice treated with N15 exhibited less disruption of TJs in colon tissues.

Conclusions

PIK3R3 was increased in clinical IBD patients with accompanying disruption of ZO-1 expression. Inhibition of PIK3R3 attenuated DSS-induced IBD symptoms in a mouse model. These findings indicated that PIK3R3 could be a therapeutic target for IBD.

中文翻译：

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PIK3R3在炎症性肠病中通过NF-kB途径调节ZO-1表达。

背景和目标

炎症性肠病（IBD）是发展为结肠炎相关癌症（CAC）的主要危险因素。以前，我们已经报道过磷酸肌醇-3-激酶调节亚基3（PIK3R3）在结直肠癌（CRC）中过表达，但我们不知道PIK3R3在IBD中的作用。

方法

我们使用免疫组织化学（IHC）和基因表达综合（GEO）数据库分析研究了IBD患者中PIK3R3和ZO-1的差异表达。将Caco-2细胞暴露于不同条件下以评估PIK3R3和ZO-1的蛋白质水平变化。用PIK3R3 / siPIK3R3转染Caco-2细胞单层膜以评估跨上皮电阻。通过免疫印迹和免疫荧光评估紧密连接蛋白的完整性。此外，在动物研究中评估了肠道通透性和紧密连接蛋白的完整性，以评估PIK3R3特异性抑制剂TAT-N 15（N15）的治疗作用。

结果

IBD患者中PIK3R3升高，并负控制ZO-1的表达。在体外，PIK3R3通过激活NF-kB途径调节ZO-1。Caco-2细胞中PIK3R3的过表达降低了跨上皮电阻（TEER），在siPIK3R3细胞中观察到相反的结果。在动物研究中，N15对PIK3R3的抑制作用有助于改善DSS诱导的肠道通透性。经N15处理的小鼠结肠组织中TJ的破坏较少。

结论

临床IBD患者的PIK3R3升高，伴随着ZO-1表达的破坏。在小鼠模型中，PIK3R3的抑制减弱了DSS诱导的IBD症状。这些发现表明PIK3R3可能是IBD的治疗靶标。