Center for Cytometry and Microscopy, Complutense University of Madrid, Madrid, Spain.
Neuroimmunomodulation. 2010;17(3):217-20. doi: 10.1159/000258728. Epub 2010 Feb 4.
CXCL12 is an important CXC chemokine involved in numerous biological processes. We had previously demonstrated the synergistic participation of CXCL12 and IL-7 in the control of both survival and proliferation of CD34(+) human thymic lymphoid progenitors. On this basis, we hypothesize a presumptive role for CXCL12 and its receptor, CXCR4, in the thymus involution. In this respect, in the current report we describe the expression of both molecules in the human thymus during aging. Our results demonstrate that, despite the profound alterations observed in the thymic epithelial microenvironment of aged thymuses, the proportions of different CD4/CD8 thymocyte subsets do not undergo significant variations. Remarkably, a strong CXCL12 expression was found in older thymuses, which appeared in the same locations as in younger thymuses: the subcapsulary and medullary areas. The proportions of CXCR4(+) cells, most of them belonging to the CD3(-) compartment, showed no important variations in the older thymuses. However, within the CD34(+) cell population, a significant reduction in the expression of CXCR4 molecules was observed.
CXCL12 是一种重要的 CXC 趋化因子，参与许多生物学过程。我们之前已经证明了 CXCL12 和 IL-7 的协同参与，控制了 CD34(+) 人类胸腺淋巴样祖细胞的存活和增殖。在此基础上，我们假设 CXCL12 及其受体 CXCR4 在胸腺萎缩中具有假定的作用。在这方面，在本报告中，我们描述了这两种分子在衰老过程中在人类胸腺中的表达。我们的结果表明，尽管衰老胸腺的胸腺上皮微环境发生了深刻的改变，但不同的 CD4/CD8 胸腺细胞亚群的比例没有发生显著变化。值得注意的是，在老年胸腺中发现了强烈的 CXCL12 表达，其出现在与年轻胸腺相同的位置：被膜下和髓质区。CXCR4(+)细胞的比例，其中大多数属于 CD3(-) 区室，在老年胸腺中没有发生重要变化。然而，在 CD34(+) 细胞群体中，CXCR4 分子的表达显著减少。
