Supplementary Materials -Table

Exposure to hypobaric hypoxia during rapid ascent to high altitudes significantly impacts intestinal barrier function. Goblet cells, as one of the primary cell types in the intestinal mucosa, play a crucial role in maintaining this barrier. However, the effects of hypobaric hypoxia on goblet cell function and the underlying molecular mechanisms remain unclear. In this study, we established a mouse model of hypobaric hypoxia exposure (simulating an altitude of 6,000 meters) and studied its effects on colonic goblet cells by transcriptomic analysis. Additionally, the hypoxia-treated (1% O2) goblet cell line Ls174t was used to investigate potential mechanisms underlying hypoxia-induced changes in goblet cells. In the present study, we discovered that hypobaric hypoxia exposure not only reduced the number of colonic goblet cells in mice by 27.6% but also impaired their mucus secretion. Transcriptome sequencing analysis of sorted goblet cells from the mice colon revealed significant changes in gene expression profiles, particularly in the expression of canonical goblet cell markers such as calcium-activated chloride channel regulator 1 (Clca1) and Fcγ-binding protein (Fcgbp). We confirmed the effects of hypobaric hypoxia/hypoxia exposure on CLCA1 and FCGBP expression at both mRNA and protein levels in mouse colonic tissues and in Ls174t cells. The expression of these canonical goblet cell marker genes was dependent on HIF-1α activity; their expression decreased upon hypoxia-induced activation of HIF-1α and increased when HIF-1α was knocked down using siRNA. Thus, hypobaric hypoxia exposure regulates the distribution and function of colonic goblet cell subsets through the HIF-1α signaling pathway.

快速攀登至高海拔地区过程中暴露于低压低氧环境，会对肠道屏障功能造成显著影响。杯状细胞（goblet cells）作为肠黏膜的主要细胞类型之一，在维持肠道屏障功能中发挥关键作用。然而，低压低氧对杯状细胞功能的影响及其潜在分子机制仍未明确。本研究构建了低压低氧暴露小鼠模型（模拟海拔6000米环境），并通过转录组学分析（transcriptomic analysis）探究其对结肠杯状细胞的影响。此外，本研究使用经1%氧气浓度低氧处理的杯状细胞系Ls174t，以探究低氧诱导杯状细胞变化的潜在机制。本研究发现，低压低氧暴露不仅使小鼠结肠杯状细胞数量减少27.6%，还损害了其黏液分泌功能。对从小鼠结肠中分选获得的杯状细胞开展转录组测序分析，结果显示其基因表达谱存在显著改变，其中钙激活氯离子通道调节因子1（Clca1）与Fcγ结合蛋白（Fcgbp）等经典杯状细胞标志物的表达变化尤为突出。本研究在小鼠结肠组织与Ls174t细胞中，于mRNA与蛋白水平验证了低压低氧/低氧暴露对CLCA1与FCGBP表达的影响。上述经典杯状细胞标志物基因的表达依赖于缺氧诱导因子-1α（HIF-1α）的活性：低氧诱导HIF-1α活化时，这些基因的表达会下调；而通过小干扰RNA（siRNA）敲低HIF-1α后，其表达则会上调。综上，低压低氧暴露可通过HIF-1α信号通路调控结肠杯状细胞亚群的分布与功能。