Macrophage migration inhibitory factor mediates protease-activated receptor 4-induced bladder pain through urothelial high mobility group box 1.
Macrophage migration inhibitory factor mediates protease-activated receptor 4-induced bladder pain through urothelial high mobility group box 1.
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DOI：
10.14814/phy2.13549
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发表时间：
2017-12
影响因子：
2.5
通讯作者：
Vera PL
中科院分区：
文献类型：
--
作者：
Ma F;Kouzoukas DE;Meyer-Siegler KL;Hunt DE;Leng L;Bucala R;Vera PL
巨噬细胞移动抑制因子(MIF)介导疼痛，但其机制尚不清楚。蛋白水解酶激活受体4(PAR4)的激活导致非膀胱炎小鼠尿路上皮MIF释放、尿路上皮高迁移率族蛋白1(HMGB1)释放和膀胱疼痛。所有这三种作用都可以通过抑制MIF来阻止，而膀胱内二硫化物HMGB1单独可以引起膀胱疼痛。本研究利用遗传MIF缺失来确定MIF是否介导了PAR4诱导的膀胱痛，并且位于HMGB1诱导的膀胱痛的上游。给野生型(C57/BL6)和MIF基因敲除(KO)小鼠膀胱内注射PAR4激活肽或二硫键HMGB1，分别于给药前和给药后24小时检测小鼠的腹部机械过敏反应。行为学检查后进行排尿参数和膀胱组织学检查。实时定量聚合酶链式反应和免疫印迹检测了幼稚野生型和MIF KO小鼠膀胱中HMGB1的mRNA和蛋白水平，而免疫荧光检测了两个品系的尿路上皮中的HMGB1蛋白水平。膀胱内激活PAR4可导致野生型小鼠的腹部机械超敏反应，但不会导致MIF KO小鼠。膀胱内二硫化物HMGB1诱导两个菌株的腹部机械超敏反应。两种治疗方法都没有导致两种菌株的排尿或膀胱组织学上的显著变化。MIF KO小鼠膀胱HMGB1mRNA和蛋白表达水平高于野生型，MIF KO膀胱尿路上皮细胞免疫染色强度高于野生型。MIF是介导PAR4诱导的膀胱疼痛的关键分子，并调节尿路上皮HMGB1的产生和释放，从而引发膀胱疼痛。
Macrophage migration inhibitory factor (MIF) mediates pain although the mechanisms are not well understood. Urothelial activation of protease activated receptor 4 (PAR4) results in urothelial MIF release, urothelial high mobility group box 1 (HMGB1) release and bladder pain in mice without bladder inflammation. All three effects are prevented by MIF inhibition while intravesical disulfide HMGB1 alone can induce bladder pain. This study utilizes genetic MIF deletion to determine whether MIF mediates PAR4‐induced bladder pain and is upstream of HMGB1‐induced bladder pain. Wild type (C57/BL6) and MIF knockout (KO) mice were treated with intravesical PAR4 activating peptide or disulfide HMGB1 and tested for abdominal mechanical hypersensitivity at baseline (before treatment) and 24 h after injection. Micturition parameters and bladder histology were examined after behavioral test. Real‐time PCR and western blotting measured HMGB1 mRNA and protein levels in the bladders of naïve wild type and MIF KO mice, while immunofluorescence measured HMGB1 protein levels in the urothelium of both strains. Intravesical PAR4 activation resulted in abdominal mechanical hypersensitivity in wild‐type mice but not MIF KO mice. Intravesical disulfide HMGB1 induced abdominal mechanical hypersensitivity in both strains. Neither treatment resulted in significant changes in micturition or bladder histology in either strain. HMGB1 mRNA and protein levels were higher in MIF KO mouse bladders and the urothelium of MIF KO bladder had greater immunostaining than the wild‐type strain. MIF is a pivotal molecule mediating PAR4‐induced bladder pain and regulating urothelial HMGB1 production and release to elicit bladder pain.