Ishimoto Hitoshi, Ginzinger David G, Matsumoto Tadashi, Hattori Yoshihisa, Furuya Masataka, Minegishi Kazuhiro, Tanaka Mamoru, Yoshimura Yasunori, Jaffe Robert B
Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Sciences, 1450 HSW, University of California-San Francisco, San Francisco, CA 94143-0556, USA.
J Clin Endocrinol Metab. 2006 Aug;91(8):3208-14. doi: 10.1210/jc.2005-2514. Epub 2006 May 30.
Matricellular proteins are a group of secreted, multifunctional extracellular matrix glycoproteins that includes thrombospondins (TSPs), tenascin-C, and secreted protein acidic and rich in cysteine (SPARC). They may be implicated in the dynamic developmental processes of the human fetal adrenal (HFA) in which the outer, definitive zone (DZ) cells are postulated to proliferate, migrate centripetally, differentiate, and populate the inner, steroidogenic fetal zone (FZ).
The objective of the study was to identify a matricellular molecule that likely plays a major role in HFA development.
Studies involved RNA, cryosections, and cell cultures from 14- to 23-wk HFAs and human adult adrenal RNA.
Measures included transcripts encoding matricellular proteins, using real-time quantitative RT-PCR; SPARC localization by immunostaining; and ACTH regulation of SPARC expression and secretion by quantitative RT-PCR and Western blot.
SPARC HFA mRNA was 100-, 700-, and 300-fold higher than TSP-1, TSP-2, and tenascin-C mRNA, respectively. HFA SPARC mRNA was 3-fold higher than adult adrenals (P < 0.005), comparable with levels in adult brain (positive control), whereas mRNAs encoding TSP-1 and TSP-2 were lower in fetal than adult adrenals. SPARC immunoreactivity was detected exclusively in the FZ, not DZ. ACTH, a key regulator of HFA growth and function, increased SPARC mRNA (by 1.7-fold at 1 nm, 48 h, P < 0.05) in isolated FZ cells but not DZ cells. ACTH up-regulation of SPARC protein was also detected in FZ cell lysates and culture medium.
Results suggest a possible role for SPARC in development of functional and/or structural zonation of the HFA.
基质细胞蛋白是一组分泌型、多功能细胞外基质糖蛋白，包括血小板反应蛋白（TSPs）、腱生蛋白-C和富含半胱氨酸的酸性分泌蛋白（SPARC）。它们可能参与人类胎儿肾上腺（HFA）的动态发育过程，在此过程中，假定外层的永久区（DZ）细胞会增殖、向心迁移、分化并填充内层的类固醇生成胎儿区（FZ）。
本研究的目的是鉴定一种可能在HFA发育中起主要作用的基质细胞分子。
研究涉及14至23周龄HFA和成人肾上腺RNA的RNA、冰冻切片和细胞培养。
指标包括使用实时定量RT-PCR检测编码基质细胞蛋白的转录本；通过免疫染色进行SPARC定位；以及通过定量RT-PCR和蛋白质印迹法检测促肾上腺皮质激素（ACTH）对SPARC表达和分泌的调节。
HFA中SPARC mRNA分别比TSP-1、TSP-2和腱生蛋白-C mRNA高100倍、700倍和300倍。HFA中SPARC mRNA比成人肾上腺高3倍（P < 0.005），与成人脑（阳性对照）中的水平相当，而编码TSP-1和TSP-2的mRNA在胎儿肾上腺中低于成人肾上腺。仅在FZ中检测到SPARC免疫反应性，而在DZ中未检测到。ACTH是HFA生长和功能的关键调节因子，可使分离的FZ细胞而非DZ细胞中的SPARC mRNA增加（在1 nM、48小时时增加1.7倍，P < 0.05）。在FZ细胞裂解物和培养基中也检测到ACTH对SPARC蛋白的上调作用。
结果表明SPARC可能在HFA功能和/或结构分区的发育中发挥作用。
