Local injection of dsRNA targeting calcitonin receptor-like receptor (CLR) ameliorates Clostridium difficile toxin A-induced ileitis
Local injection of dsRNA targeting calcitonin receptor-like receptor (CLR) ameliorates Clostridium difficile toxin A-induced ileitis
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DOI：
10.1073/pnas.1219733110
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发表时间：
2013-01-08
影响因子：
11.1
通讯作者：
Grady, Eileen F.
中科院分区：
文献类型：
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作者：
Bhargava, Aditi;Clifton, Matthew S.;Grady, Eileen F.
艰难梭菌毒素(TX)引起的肠炎是一种越来越受到临床关注的医院疾病，但艰难梭菌TXA炎症的局部介质尚不清楚。强大的血管扩张剂降钙素基因相关肽通过降钙素受体样受体(CLR)介导神经源性炎症。在这里，我们研究了通过局部预注射双链RNA来减少TXA回肠炎的回肠特异性CLR的效果。用CLR dsRNA处理7d后，CLR免疫反应性降低，而非CLR dsRNA处理不降低。随后在同一部位注射TXA后，非CLR dsRNA组大鼠的CLR增加，但CLR dsRNA组大鼠的CLR增加，证明局部注射dsRNA能有效地防止局部TXA引起的CLR免疫反应性增加。在非CLR dsRNA预处理后，TXA诱导了强劲的肠道分泌、髓过氧化物酶活性和炎症的组织病理学指标，包括上皮损伤、充血、中性粒细胞浸润、杯状细胞粘蛋白丢失和肥大细胞数量增加。CLR dsRNA预处理后，TXA引起的肠道分泌改变和组织病理炎症反应得到改善，包括正常的粘蛋白染色和较少的滞留肥大细胞。CLR的缺失阻止了TXA介导的核因子-kappaB的激活，并伴随着pERK1/2和TNF-αmRNA的增加。局部产生的CLR通过MAPK信号转导和肿瘤坏死因子-α在TXA肠炎中发挥促炎作用。本文报道的结果强烈表明，针对CLR的局部注射dsRNA可能是治疗一种不断增长的临床相关的医院获得性疾病艰难梭菌感染的有效局部治疗方法。
Enteritis caused by Clostridium difficile toxin (Tx) is a nosocomial disease of increasing clinical concern, but the local mediators of C. difficile TxA inflammation are unknown. The potent vasodilator calcitonin gene-related peptide mediates neurogenic inflammation via the calcitonin receptor-like receptor (CLR). Here we examined the ileum-specific effects of reducing CLR on TxA ileitis by local preinjection of double-stranded RNAs. Treatment with CLR dsRNA for 7 d decreased CLR immunoreactivity, whereas treatment with non-CLR dsRNA did not. Subsequent injection of TxA in the same location increased CLR in rats treated with non-CLR dsRNA but not in rats treated with CLR dsRNA, documenting that local injection of dsRNA is effective in preventing the increase in CLR immunoreactivity in response to local TxA. After non-CLR dsRNA pretreatment, TxA induced robust intestinal secretion, myeloperoxidase activity, and histopathologic indications of inflammation including epithelial damage, congestion, neutrophil infiltration, loss of mucin from goblet cells, and increase in mast cell numbers. After CLR dsRNA pretreatment, TxA-induced changes in intestinal secretion and histopathologic inflammation were improved, including normal mucin staining and fewer resident mast cells. Loss of CLR prevented TxA-mediated activation of NF-kappa B and concomitant increases in pERK1/2 and TNF-alpha mRNA. Locally produced CLR plays a proinflammatory role in TxA ileitis via MAPK signaling and TNF-alpha. The results reported here strongly suggest that a local injection of dsRNA targeting CLR could be an effective local therapeutic approach at the inflammation site in the treatment of a growing, clinically relevant hospital-acquired disease, C. difficile infection.