Gefen-Halevi Shiraz, Rachmut Itzhak H, Molakandov Kfir, Berneman Dana, Mor Eytan, Meivar-Levy Irit, Ferber Sarah
Sheba Regenerative Medicine, Stem cells and Tissue engineering Center , Sheba Medical Center, Tel-Hashomer, Israel.
Cell Reprogram. 2010 Dec;12(6):655-64. doi: 10.1089/cell.2010.0030.
Reprogramming adult mammalian cells is an attractive approach for generating cell-based therapies for degenerative diseases, such as diabetes. Adult human liver cells exhibit a high level of developmental plasticity and have been suggested as a potential source of pancreatic progenitor tissue. An instructive role for dominant pancreatic transcription factors in altering the hepatic developmental fate along the pancreatic lineage and function has been demonstrated. Here we analyze whether transcription factors expressed in mature pancreatic β-cells preferentially activate β-cell lineage differentiation in liver. NKX6.1 is a transcription factor uniquely expressed in β-cells of the adult pancreas, its potential role in reprogramming liver cells to pancreatic lineages has never been analyzed. Our results suggest that NKX6.1 activates immature pancreatic markers such as NGN-3 and ISL-1 but not pancreatic hormones gene expression in human liver cells. We hypothesized that its restricted capacity to activate a wide pancreatic repertoire in liver could be related to its incapacity to activate endogenous PDX-1 expression in liver cells. Indeed, the complementation of NKX6.1 by ectopic PDX-1 expression substantially and specifically promoted insulin expression and glucose regulated processed hormone secretion to a higher extent than that of PDX-1 alone, without increasing the reprogrammed cells. This may suggest a potential role for NKX6.1 in promoting PDX-1 reprogrammed cells maturation along the β-cell-like lineage. By contrast, NKX6.1 repressed PDX-1 induced proglucagon gene expression. The individual and concerted effects of pancreatic transcription factors in adult extra-pancreatic cells, is expected to facilitate developing regenerative medicine approaches for cell replacement therapy in diabetics.
重编程成年哺乳动物细胞是一种极具吸引力的方法，可用于生成针对诸如糖尿病等退行性疾病的细胞疗法。成人肝细胞表现出高度的发育可塑性，并被认为是胰腺祖细胞组织的潜在来源。已证明主要胰腺转录因子在改变肝脏沿胰腺谱系和功能的发育命运方面具有指导作用。在这里，我们分析成熟胰腺β细胞中表达的转录因子是否优先激活肝脏中的β细胞谱系分化。NKX6.1是一种在成年胰腺β细胞中独特表达的转录因子，其在将肝细胞重编程为胰腺谱系中的潜在作用从未被分析过。我们的结果表明，NKX6.1可激活未成熟的胰腺标志物，如NGN-3和ISL-1，但不能激活人类肝细胞中胰腺激素基因的表达。我们假设，其在肝脏中激活广泛胰腺基因库的能力受限可能与其无法激活肝细胞中内源性PDX-1表达有关。事实上，异位表达PDX-1对NKX6.1的补充显著且特异性地促进了胰岛素表达和葡萄糖调节的加工激素分泌，其程度高于单独的PDX-1，且不会增加重编程细胞的数量。这可能表明NKX6.1在促进沿β细胞样谱系的PDX-1重编程细胞成熟方面具有潜在作用。相比之下，NKX6.1抑制了PDX-1诱导的胰高血糖素原基因表达。预计胰腺转录因子在成年胰腺外细胞中的个体和协同作用将有助于开发用于糖尿病患者细胞替代治疗的再生医学方法。
