Knies U E, Kröger S, Clauss M
Department of Molecular Cell Biology, Max-Planck-Institute für Physiologische und Klinische Forschung, Parkstrasse 1, 61231 Bad Nauheim, Germany.
Apoptosis. 2000 Apr;5(2):141-51. doi: 10.1023/a:1009632712876.
Endothelial monocyte-activating polypeptide II (EMAP II) is a chemoattractant for monocytes and granulocytes. EMAP II is translated as a precursor protein, proEMAP II, and is proteolytically cleaved to become the mature, biologically active cytokine. In this study we show that the EMAP II mRNA and the EMAP II precursor protein are constitutively expressed by all cell types analyzed in vitro, whereas the mature cytokine is only present in the supernatant of apoptotic cells. During mouse embryogenesis we found widespread expression of the EMAP II mRNA with transcripts being abundant in areas of tissue remodeling, where a large number of apoptotic cells could be detected by TUNEL staining. In the adult mouse, strong expression of the EMAP II mRNA is restricted to the brain, testis and thymus. Interestingly, prominent signals for EMAP II mRNA are found in local correlation with sites of apoptosis in thymus and testis but not in the brain. We propose that during development, the generation and release of the mature EMAP II may provide a mechanism for the recruitment of phagocytic cells to sites of programmed cell death. In the adult brain, the generation of mature EMAP II may contribute to the recruitment of monocytes and the immunosurveillance of this tissue.
内皮单核细胞激活多肽II（EMAP II）是一种单核细胞和粒细胞的趋化因子。EMAP II最初被翻译为前体蛋白proEMAP II，然后经过蛋白水解切割成为成熟的、具有生物活性的细胞因子。在本研究中，我们发现，体外分析的所有细胞类型均组成性表达EMAP II mRNA和EMAP II前体蛋白，而成熟细胞因子仅存在于凋亡细胞的上清液中。在小鼠胚胎发育过程中，我们发现EMAP II mRNA广泛表达，转录本在组织重塑区域丰富，在这些区域通过TUNEL染色可检测到大量凋亡细胞。在成年小鼠中，EMAP II mRNA的强表达局限于脑、睾丸和胸腺。有趣的是，在胸腺和睾丸中，EMAP II mRNA的显著信号与凋亡位点局部相关，但在脑中未发现这种相关性。我们推测，在发育过程中，成熟EMAP II的产生和释放可能为将吞噬细胞募集到程序性细胞死亡位点提供一种机制。在成年脑中，成熟EMAP II的产生可能有助于单核细胞的募集和该组织的免疫监视。
