Pilipow Karolina, Basso Veronica, Migone Nicola, Mondino Anna
Lymphocyte Activation Unit, Immunology, Transplantation and Infectious Disease Division, San Raffaele Scientific Institute, Milano, Italy; Università Vita-Salute San Raffaele, Milano, Italy.
Lymphocyte Activation Unit, Immunology, Transplantation and Infectious Disease Division, San Raffaele Scientific Institute, Milano, Italy.
PLoS One. 2014 Mar 14;9(3):e91952. doi: 10.1371/journal.pone.0091952. eCollection 2014.
Germline and somatic biallelic mutations of the Tuberous sclerosis complex (TSC) 1 and TSC2 gene products cause TSC, an autosomal dominant multifocal hamartomatosis with variable neurological manifestations. The consequences of TSC1 or TSC2 loss in cells of hematopoietic origin have recently started to be unveiled in mice and showed to hinder the development of proper T cell immunity. To date, the consequences of germline TSC1 mutations and/or its loss in mature human T cells remain to be determined. To address these issues, we analyzed subset representation, phenotype and responsiveness to mitogens in T cells from patients with inherited monoallelic TSC1 mutations, and induced shRNA-mediated TSC1 down-regulation in primary and transformed human T cells. We report that, the distribution of peripheral CD4 and CD8 T cell subsets, their cytokine-secretion profile, and responsiveness to in vitro stimulation were largely preserved in TSC subjects with monoallelic TSC1 germline mutations when compared to healthy controls. Sufficient levels of hamartin and tuberin and proper control of mTOR-dependent signaling in primary T cells from TSC subjects best explained this. In contrast, shRNA-induced down-regulation of TSC1, likely mimicking biallelic inactivation of TSC1, compromised hamartin and tuberin expression and mTORC2/AKT/FoxO1/3 signaling causing both primary and transformed T cells to die by apoptosis. Thus, our results indicate that, while one functional TSC1 allele preserves human T lymphocytes development and homeostasis, TSC1 acute down-regulation is detrimental to the survival of both primary and transformed T cells.
结节性硬化症（TSC）1和TSC2基因产物的种系和体细胞双等位基因突变会导致TSC，这是一种常染色体显性多灶性错构瘤病，具有多种神经学表现。最近在小鼠中开始揭示造血来源细胞中TSC1或TSC2缺失的后果，结果显示其会阻碍正常T细胞免疫的发育。迄今为止，种系TSC1突变及其在成熟人类T细胞中的缺失后果仍有待确定。为了解决这些问题，我们分析了患有遗传性单等位基因TSC1突变患者T细胞中的亚群代表性、表型和对有丝分裂原的反应性，并在原代和转化的人类T细胞中诱导了shRNA介导的TSC1下调。我们报告称，与健康对照相比，携带单等位基因TSC1种系突变的TSC患者外周CD4和CD8 T细胞亚群的分布、细胞因子分泌谱以及对体外刺激的反应性在很大程度上得以保留。TSC患者原代T细胞中足够水平的错构瘤蛋白和结节蛋白以及对mTOR依赖性信号的适当控制最能解释这一现象。相反，shRNA诱导的TSC1下调可能模拟了TSC1的双等位基因失活，损害了错构瘤蛋白和结节蛋白的表达以及mTORC2/AKT/FoxO1/3信号传导，导致原代和转化的T细胞通过凋亡死亡。因此，我们的结果表明，虽然一个功能性TSC1等位基因可维持人类T淋巴细胞的发育和稳态，但TSC1的急性下调对原代和转化T细胞的存活均有害。
