Disulfide high mobility group box-1 causes bladder pain through bladder Toll-like receptor 4.
Disulfide high mobility group box-1 causes bladder pain through bladder Toll-like receptor 4.
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DOI：
10.1186/s12899-017-0032-9
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发表时间：
2017-05-25
期刊：
影响因子：
--
通讯作者：
Vera PL
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文献类型：
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作者：
Ma F;Kouzoukas DE;Meyer-Siegler KL;Westlund KN;Hunt DE;Vera PL
膀胱疼痛是几种泌尿系统疾病（例如感染、膀胱疼痛综合征/间质性膀胱炎、癌症）的突出症状。了解膀胱疼痛的机制很重要，特别是当疼痛不伴有膀胱病理时。刺激尿路上皮中的蛋白酶激活受体4（PAR 4）通过释放尿路上皮高迁移率族蛋白-1（HMGB 1）导致膀胱疼痛。HGMB 1具有两种功能活性氧化还原状态（二硫化物和全巯基），并且尚不清楚哪种状态形成了膀胱疼痛。因此，我们研究了特定HMGB 1氧化还原形式的膀胱内给药是否会引起雌性C57 BL/6小鼠给药后24小时的腹部机械超敏反应、排尿变化和膀胱炎症。此外，我们确定了特定的HMGB 1受体，Toll样受体4（TLR 4）或晚期糖基化终产物受体（RECEPTOR），介导HMGB 1诱导的变化。二硫键HMGB 1膀胱灌注（5、10、20 μg/150 μl）后24 h引起腹部机械超敏反应。相比之下，在任何测试剂量（1、2、5、10、20 μg/150 μl）下，全巯基HMGB 1均未产生腹部机械超敏反应。两种HMGB 1氧化还原形式仅在最高试验剂量（20 μg/150 μl）下引起排尿变化，而在所有剂量下均引起轻度膀胱水肿和反应性变化。我们随后测试了膀胱内二硫化物HMGB 1（10 μg/150 μl;不产生炎症的剂量）的作用是否被全身性（i. p.）或局部（膀胱内）给予TLR 4拮抗剂（TAK-242）或TLR 4拮抗剂（FPS-ZM 1）。TAK-242（3 mg/kg）或FPS-ZM 1（10 mg/kg）全身给药可预防HMGB 1诱导的腹部机械性超敏反应，而仅膀胱内TLR 4拮抗剂预处理（1.5 mg/ml;非TBI）具有此作用。HMGB 1的二硫键形式通过激活膀胱中的TLR 4受体直接介导膀胱疼痛（而不是继发于炎症或损伤）。因此，TLR 4受体是膀胱疼痛的特异性局部靶标。
Bladder pain is a prominent symptom in several urological conditions (e.g. infection, painful bladder syndrome/interstitial cystitis, cancer). Understanding the mechanism of bladder pain is important, particularly when the pain is not accompanied by bladder pathology. Stimulation of protease activated receptor 4 (PAR4) in the urothelium results in bladder pain through release of urothelial high mobility group box-1 (HMGB1). HGMB1 has two functionally active redox states (disulfide and all-thiol) and it is not known which form elicits bladder pain. Therefore, we investigated whether intravesical administration of specific HMGB1 redox forms caused abdominal mechanical hypersensitivity, micturition changes, and bladder inflammation in female C57BL/6 mice 24 hours post-administration. Moreover, we determined which of the specific HMGB1 receptors, Toll-like receptor 4 (TLR4) or receptor for advanced glycation end products (RAGE), mediate HMGB1-induced changes. Disulfide HMGB1 elicited abdominal mechanical hypersensitivity 24 hours after intravesical (5, 10, 20 μg/150 μl) instillation. In contrast, all-thiol HMGB1 did not produce abdominal mechanical hypersensitivity in any of the doses tested (1, 2, 5, 10, 20 μg/150 μl). Both HMGB1 redox forms caused micturition changes only at the highest dose tested (20 μg/150 μl) while eliciting mild bladder edema and reactive changes at all doses. We subsequently tested whether the effects of intravesical disulfide HMGB1 (10 μg/150 μl; a dose that did not produce inflammation) were prevented by systemic (i.p.) or local (intravesical) administration of either a TLR4 antagonist (TAK-242) or a RAGE antagonist (FPS-ZM1). Systemic administration of either TAK-242 (3 mg/kg) or FPS-ZM1 (10 mg/kg) prevented HMGB1 induced abdominal mechanical hypersensitivity while only intravesical TLR4 antagonist pretreatment (1.5 mg/ml; not RAGE) had this effect. The disulfide form of HMGB1 mediates bladder pain directly (not secondary to inflammation or injury) through activation of TLR4 receptors in the bladder. Thus, TLR4 receptors are a specific local target for bladder pain.