Overexpression of phosphorylated STAT-1α in the labial salivary glands of patients with Sjogren's syndrome
Overexpression of phosphorylated STAT-1α in the labial salivary glands of patients with Sjogren's syndrome
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DOI：
10.1002/art.22176
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发表时间：
2006-11-01
影响因子：
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通讯作者：
Sumida, Takayuki
中科院分区：
文献类型：
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作者：
Wakamatsu, Ei;Matsumoto, Isao;Sumida, Takayuki
目标。为了阐明干燥综合征(SS)的分子机制，我们分析了干扰素-γ(干扰素-γ)诱导基因之一的STAT-1基因在干燥综合征患者唇涎腺(LSG)中的功能。用实时定量聚合酶链式反应检测STAT-1信使RNA的表达，用Western印迹和免疫组织化学方法检测STAT-1蛋白(Tyr(701)和Ser(727)pSTAT-1)的磷酸化。用实时定量聚合酶链式反应和免疫组织化学方法检测干扰素-γ诱导的10-kd蛋白(IP-10)、干扰素调节因子-1(IRF-1)和Fas的表达。SS患者LSG中高表达STAT-1α和STAT-1β。免疫印迹分析显示SS LSGs中STAT-1α蛋白表达水平高于3个对照LSGs组，而STAT-1β蛋白表达水平不明显。此外，在SS LSGs中还特异性地检测到Tyr(701)和Ser(727)pSTAT-1α蛋白。免疫组织化学分析显示，Tyr(701)pSTAT-1在SS患者浸润性淋巴细胞及邻近导管上皮细胞中有表达。Ser(727)pSTAT-1仅定位于SS LSGs的导管上皮。STAT-1诱导基因IP-10、IRF-1和Fas基因在SS LSGs中高表达，并与Ser(727)pSTAT-1阳性细胞共存，但不与Tyr(701)pSTAT-1阳性细胞共定位。我们发现了SS患者LSG中STAT-1α基因和蛋白表达上调的证据，以及SS患者导管上皮中存在pSTAT-1α的证据。我们的发现提示STAT-1α，特别是Ser(727)pSTAT-1，可能是SS发病机制中的一个关键分子。
Objective. To clarify the molecular mechanisms of Sjogren's syndrome (SS), we analyzed the functional role of the STAT-1 gene, one of the interferon-gamma (IFN gamma)inducible genes, in labial salivary glands (LSGs) from SS patients.Methods. The expression of STAT-1 messenger RNA (mRNA) was examined by real-time polymerase chain reaction (PCR) analysis, and the phosphorylation of STAT-1 protein (Tyr(701) and Ser(727) pSTAT-1) was investigated by Western blot and immunohistochemical analyses. The expression of IFN gamma-inducible 10-kd protein (IP-10), IFN regulatory factor 1 (IRF-1), and Fas was also examined by real-time PCR and immunohistochemical analyses.Results. STAT-1 alpha and STAT-1 beta mRNA were highly expressed in LSGs from SS patients. The level of STAT-1 alpha protein in SS LSGs was higher than that in 3 control LSGs, whereas STAT-1 beta protein was not clearly detected by Western blot analysis. Moreover, Tyr(701) and Ser(727) pSTAT-1 alpha proteins were specifically detected in SS LSGs. Immunohistochemical analysis showed localization of Tyr(701) pSTAT-1 in infiltrating lymphocytes and the adjacent ductal epithelium from SS patients. Ser(727) pSTAT-1 was localized only in the ductal epithelium of SS LSGs. The STAT-1-inducible genes IP-10 and IRF-1 and the Fas genes were highly expressed in SS LSGs and were colocalized with Ser(727) pSTAT-1-positive, but not Tyr(701) pSTAT-1-positive, cells.Conclusion. We found evidence of the upregulation of STAT-1 alpha mRNA and protein in LSGs from SS patients, as well as the presence of pSTAT-1 alpha in ductal epithelium from SS patients. Our findings suggest that STAT-1 alpha, especially Ser(727) pSTAT-1, may function as a key molecule in the pathogenesis of SS.