Institute of Stem Cell and Translational Cancer Research, Chang Gung Memorial Hospital at Linkou, 333 Taoyuan, Taiwan.
Department of Biotechnology, Ming-Chuan University, 333 Taoyuan, Taiwan.
Proc Natl Acad Sci U S A. 2020 Nov 3;117(44):27435-27444. doi: 10.1073/pnas.2003155117. Epub 2020 Oct 21.
Conversion of human pluripotent stem cells from primed to naïve state is accompanied by altered transcriptome and methylome, but glycosphingolipid (GSL) profiles in naïve human embryonic stem cells (hESCs) have not been systematically characterized. Here we showed a switch from globo-(SSEA-3, SSEA-4, and Globo H) and lacto-series (fucosyl-Lc4Cer) to neolacto-series GSLs (SSEA-1 and H type 2 antigen), along with marked down-regulation of β-1,3-galactosyltransferase (B3GALT5) upon conversion to naïve state. CRISPR/Cas9-generated knockout (KO) hESCs displayed an altered GSL profile, increased cloning efficiency and intracellular Ca, reminiscent of the naïve state, while retaining differentiation ability. The altered GSLs could be rescued through overexpression of B3GALT5. KO cells cultured with 2iLAF exhibited naïve-like transcriptome, global DNA hypomethylation, and X-chromosome reactivation. In addition, -KO rendered hESCs more resistant to calcium chelator in blocking entry into naïve state. Thus, loss of B3GALT5 induces a distinctive state of hESCs displaying unique GSL profiling with expression of neolacto-glycans, increased Ca, and conducive for transition to naïve pluripotency.
人类多能干细胞从初始状态向原始状态的转化伴随着转录组和甲基化组的改变，但原始人类胚胎干细胞（hESC）中的糖脂（GSL）谱尚未得到系统表征。在这里，我们发现从Globoside（SSEA-3、SSEA-4 和 Globo H）和 Lacto-series（Fucosyl-Lc4Cer）向Neolacto-series GSLs（SSEA-1 和 H type 2 antigen）转变，同时伴随着向原始状态转化时β-1,3-半乳糖基转移酶（B3GALT5）的显著下调。CRISPR/Cas9 生成的敲除（KO）hESC 显示出改变的 GSL 谱，克隆效率和细胞内 Ca 增加，类似于原始状态，同时保留分化能力。通过过表达 B3GALT5 可以挽救改变的 GSL。用 2iLAF 培养的 KO 细胞表现出原始样转录组、全基因组低甲基化和 X 染色体重新激活。此外，-KO 使 hESC 对钙螯合剂阻断进入原始状态的作用更具抗性。因此，B3GALT5 的缺失诱导 hESC 呈现独特的状态，表现出独特的 GSL 谱，表达 Neolacto-glycans，增加 Ca，有利于向原始多能性的转变。
