Marie J, Wakkach A, Coudray A, Chastre E, Berrih-Aknin S, Gespach C
Institut National de la Santé et de la Recherche Médicale, Unit 482, Signalisation et Fonctions Cellulaires, Applications au Diabète et aux Cancers Digestifs, Hôpital Saint-Antoine, Paris, France.
J Immunol. 1999 Feb 15;162(4):2103-12.
The molecular and functional expression of serpentine membrane receptors for vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), and calcitonin (CT) were characterized in human thymus and thymomas from myasthenia gravis (MG) patients and thymic epithelial cells either in primary culture (PTEC) or transformed by the simian virus 40 large T (SV40LT) oncogene (LT-TEC). Using RT-PCR combined with Southern analysis, we identified the PCR products corresponding to the receptor (-R) transcripts for VIP, CGRP, and CT in thymus from control subjects and MG patients with either hyperplasia or thymoma. Similar expressions of the VIP- and CGRP-R transcripts were observed in PTEC, whereas the CT-R message was not detected. In LT-TEC, the signals for VIP-R, CGRP-R, and CT-R transcripts were seen with a lower intensity than those in control and MG thymus. In agreement with our molecular analysis, 1) VIP was the most potent peptide among VIP-related peptides (VIP > PACAP > PHM > PHV) to stimulate cAMP production through specific type 1 VIP receptors in both PTEC and LT-TEC; 2) cAMP generation was induced by CGRP in PTEC and by CT in LT-TEC; 3) in frozen thymic sections and by flow cytometry, type 1 VIP-R, CGRP-R, and CT-R were localized in epithelial cells; and 4) in parallel, the transcription of the acetylcholine receptor alpha subunit (the main autoantigen in MG) was induced by CGRP and CT in PTEC and LT-TEC, respectively. Our data suggest that the neuroendocrine peptides VIP, CGRP, and CT may exert functional roles during MG and malignant transformation of the human thymus.
对重症肌无力（MG）患者的人胸腺、胸腺瘤以及原代培养（PTEC）或经猿猴病毒40大T（SV40LT）癌基因转化（LT-TEC）的胸腺上皮细胞中血管活性肠肽（VIP）、降钙素基因相关肽（CGRP）和降钙素（CT）的蛇形膜受体的分子和功能表达进行了表征。通过逆转录聚合酶链反应（RT-PCR）结合Southern分析，我们在对照受试者以及患有增生或胸腺瘤的MG患者的胸腺中鉴定出了与VIP、CGRP和CT受体（-R）转录本相对应的PCR产物。在PTEC中观察到VIP和CGRP-R转录本有相似的表达，而未检测到CT-R信息。在LT-TEC中，VIP-R、CGRP-R和CT-R转录本的信号强度低于对照和MG胸腺中的信号强度。与我们的分子分析一致的是：1）在PTEC和LT-TEC中，VIP是VIP相关肽（VIP > PACAP > PHM > PHV）中通过特异性1型VIP受体刺激环磷酸腺苷（cAMP）产生的最有效肽；2）PTEC中CGRP诱导cAMP生成，LT-TEC中CT诱导cAMP生成；3）在冷冻胸腺切片和通过流式细胞术检测时，1型VIP-R、CGRP-R和CT-R定位于上皮细胞；4）同时，PTEC和LT-TEC中，CGRP和CT分别诱导乙酰胆碱受体α亚基（MG中的主要自身抗原）的转录。我们的数据表明，神经内分泌肽VIP、CGRP和CT可能在MG及人胸腺的恶性转化过程中发挥功能作用。
