Laboratory of Neuroplasticity and Neuroproteomics, Department of Woman and Child, Katholieke Universiteit Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
Peptides. 2009 Oct;30(10):1822-32. doi: 10.1016/j.peptides.2009.07.010. Epub 2009 Jul 23.
Thymosin beta 4 (Tbeta4) is a peptide of 43 amino acids, mainly recognized as a regulator of actin polymerization by sequestering G-actin. Meanwhile, the peptide has been implicated in lymphocyte maturation, carcinogenesis, apoptosis, angiogenesis, blood coagulation and wound healing. The peptide is also involved in lesion-induced neuroplasticity through microglia upregulation and it participates in the growth of neuronal processes. However, its precise cellular localization throughout the entire body of the mouse has not been documented. We therefore initiated a detailed investigation of the tissue distribution and cellular expression of the Tbeta4 peptide and its precursor mRNA by immunocytochemistry and in situ hybridization, respectively. In the brain, Tbeta4 was clearly present in neurons of the olfactory bulb, neocortex, hippocampus, striatum, amygdala, piriform cortex and cerebellum, and in microglia across the entire brain. We further localized Tbeta4 in cells, typically with many processes, inside thymus, spleen, lung, kidney, liver, adrenal gland, stomach and intestine. Remarkably, Tbeta4 was thus associated with microglia and macrophages, the differentiated phagocytic cells residing in every tissue. Motility and phagocytosis, two important activities of macrophages, depend on actin, which can explain the presence of Tbeta4 in these cells.
胸腺肽β 4（Tβ4）是一种由 43 个氨基酸组成的肽，主要通过隔离 G-肌动蛋白来调节肌动蛋白聚合。同时，该肽已被牵连到淋巴细胞成熟、癌变、细胞凋亡、血管生成、血液凝固和伤口愈合中。该肽还通过小胶质细胞的上调参与损伤诱导的神经可塑性，并参与神经元过程的生长。然而，其在整个小鼠体内的确切细胞定位尚未得到记录。因此，我们通过免疫细胞化学和原位杂交分别启动了对 Tβ4 肽及其前体 mRNA 的组织分布和细胞表达的详细研究。在大脑中，Tβ4 明显存在于嗅球、新皮质、海马、纹状体、杏仁核、梨状皮层和小脑的神经元中，以及整个大脑的小胶质细胞中。我们进一步将 Tβ4 定位在胸腺、脾脏、肺、肾脏、肝脏、肾上腺、胃和肠道等组织中的具有许多突起的细胞内。值得注意的是，Tβ4 与小胶质细胞和巨噬细胞有关，这些分化的吞噬细胞存在于每种组织中。运动性和吞噬作用是巨噬细胞的两个重要活动，这两个活动都依赖于肌动蛋白，这可以解释这些细胞中存在 Tβ4。
