alpha-melanocyte-stimulating hormone suppresses bleomycin-induced collagen synthesis and reduces tissue fibrosis in a mouse model of scleroderma: melanocortin peptides as a novel treatment strategy for scleroderma?
alpha-melanocyte-stimulating hormone suppresses bleomycin-induced collagen synthesis and reduces tissue fibrosis in a mouse model of scleroderma: melanocortin peptides as a novel treatment strategy for scleroderma?
复制标题
α-黑素细胞刺激激素抑制博来霉素诱导的胶原蛋白合成并减少硬皮病小鼠模型中的组织纤维化：黑皮质素肽作为硬皮病的新型治疗策略？
作者：
Agatha Kokot;A. Sindrilaru;M. Schiller;C. Sunderkötter;C. Kerkhoff;B. Eckes;K. Scharffetter;T. Luger;M. Böhm
目的
最近，我们发现人皮肤成纤维细胞（HDF）表达黑皮质素1受体（MC-1 R），其结合α-黑素细胞刺激激素（α-MSH）。为了寻找硬皮病（系统性硬化症[SSc]）的新疗法，我们使用博莱霉素（BLM）模型来研究α-MSH对胶原合成和纤维化的影响。
方法
通过实时逆转录-聚合酶链反应（RT-PCR）和Western印迹分析确定HDFs中的胶原表达。信号转导研究包括药理学阻断、免疫荧光分析、蛋白质印迹法和启动子分析。通过荧光激活细胞分选仪分析测定氧化应激，通过实时RT-PCR和Western印迹分析测定抗氧化酶水平。通过组织学、免疫组织化学、实时RT-PCR和蛋白质分析评估α-MSH在硬皮病BLM小鼠模型中的作用。通过RT-PCR测定SSc患者皮肤和HDF样本中MC-1 R和前阿黑皮素（POMC）的表达，并与正常对照样本进行比较。
结果
用α-MSH（和相关肽）治疗抑制BLM诱导的HDFs中I型和III型胶原蛋白的表达，并且这种作用是cAMP依赖性的。BLM和α-MSH都不改变Smad信号，但抗氧化剂抑制BLM诱导的胶原蛋白表达。此外，α-MSH抑制BLM诱导的氧化应激，并增强超氧化物歧化酶2（SOD 2）和血红素加氧酶1（HO-1）的表达。在BLM小鼠模型中，α-MSH减少了皮肤纤维化和胶原蛋白含量，并增加了SOD 2和HO-1的组织水平。在SSc患者的皮肤和HDF中，检测到MC-1 R和POMC信使RNA，但与健康对照组相比无差异。
结论
通过MC-1 R发挥其作用的α-黑素细胞刺激激素和相关肽可能为治疗纤维化疾病如硬皮病提供新的抗纤维化治疗工具。
OBJECTIVE
Recently, we found that human dermal fibroblasts (HDFs) express melanocortin 1 receptors (MC-1R) that bind alpha-melanocyte-stimulating hormone (alpha-MSH). In search of novel therapies for scleroderma (systemic sclerosis [SSc]), we used the bleomycin (BLM) model to investigate the effects of alpha-MSH on collagen synthesis and fibrosis.
METHODS
Collagen expression in HDFs was determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses. Signal transduction studies included pharmacologic blockade, immunofluorescence analysis, Western blotting, and reporter-promoter assays. Oxidative stress was measured by fluorescence-activated cell sorter analysis, and anti-oxidative enzyme levels were determined by real-time RT-PCR and Western blot analyses. The effect of alpha-MSH in the BLM mouse model of scleroderma was assessed by histologic, immunohistochemical, real-time RT-PCR, and protein analyses. Expression of MC-1R and pro-opiomelanocortin (POMC) in skin and HDF samples from patients with SSc was determined by RT-PCR and compared with that in samples from normal controls.
RESULTS
Treatment with alpha-MSH (and related peptides) suppressed BLM-induced expression of type I and type III collagen in HDFs, and this effect was cAMP-dependent. Neither BLM nor alpha-MSH altered Smad signaling, but antioxidants inhibited BLM-induced collagen expression in vitro. In addition, alpha-MSH suppressed BLM-induced oxidative stress and enhanced the expression of superoxide dismutase 2 (SOD2) and heme oxygenase 1 (HO-1). In the BLM mouse model, alpha-MSH reduced skin fibrosis and collagen content and increased tissue levels of SOD2 and HO-1. In skin and HDFs from patients with SSc, both MC-1R and POMC messenger RNAs were detected, but there were no differences compared with healthy controls.
CONCLUSION
Alpha-melanocyte-stimulating hormone and related peptides that exert their effects via MC-1R may provide a novel antifibrogenic therapeutic tool for the treatment of fibrotic diseases such as scleroderma.