RNA sequencing of Jejunum of WT and IL23 expression mice (KSR23). RNA sequencing of Jejunum of WT and IL23 expression mice (KSR23)

The goal of this study is to check if elevated level of IL-23 and/or its downstream cytokines affect the gene expression in the jejunum of newborn mice. We engineered a mice strain in which the expression of IL-23 was directed to the keratinocytes (KSR23). The KSR23 mice had normal body weight at birth and much smaller than their control littermates at day 5. KSR23 mice died prematurely (before 15 days of age), but displayed no signs of disease in the skin, intestine, or in other organs examined. To investigate if elevated level of IL-23 and/or its downstreamcytokines could affect body growth, we examined the transcriptome of the the intestine, which are critical for the processing and absorption of nutrients. Jejunum mRNA profiles of 5-day-old WT and KSR23 were generated by deep sequencing. The transcriptome of the Jejunum of KSR23 mice at P5 differed significantly from that of their control littermates (WT). Several genes were differentially expressed, including IL-22, and genes that are downstream of it such as Reg3 genes and digestive enzymes also produced by the jejunum. Kegg pathway analysis of WT and KSR23 jejunum indicated that genes involved in protein digestion and absorption such as chymotrypsinogen B1 (Ctrb1), trypsinogen (Prss1), trypsin (Tyr5 and Tyr4), caboxypeptidase a1 (Cpa1) and chymotrypsin-like elastase family member 3b (Cela3b), were downregulated in the intestine of KSR23 mice. Transcriptome analysis also showed decreased expression of several genes involved in the regulation of the very low-density lipoprotein particle pathway (VLDL). These particles regulate fat and cholesterol release into the bloodstream. Together, these results indicate that systemic expression of IL-23, and other cytokines, correlated with significant transcriptional changes in genes that regulate food processing in the intestine. Overall design: Jejunum mRNA profiles of 5-day old wild type (WT) and IL23 expression mice (KSR23) were generated by deep sequencing using Illumina Nextseq 500.

本研究旨在探究白细胞介素23（IL-23）及其下游细胞因子水平升高是否会影响新生小鼠空肠的基因表达。我们构建了一种小鼠品系，使IL-23的表达定向于角质形成细胞（keratinocytes），该品系命名为KSR23。KSR23小鼠出生时体重正常，但在出生后第5天时体型显著小于同窝野生型对照小鼠。KSR23小鼠会提前死亡（早于15日龄），但在皮肤、肠道及其他检测器官中未观察到明显病变征象。

为探究IL-23及其下游细胞因子水平升高是否会影响机体生长，我们对肠道的转录组进行了分析——肠道是营养物质消化与吸收的关键器官。我们通过深度测序获取了5日龄野生型（WT）与KSR23小鼠空肠的mRNA表达谱。

P5日龄KSR23小鼠空肠的转录组与同窝对照（WT）存在显著差异。存在多个差异表达基因，包括IL-22及其下游的Reg3家族基因，以及空肠亦可分泌的消化酶类基因。

KEGG通路分析显示，与蛋白质消化吸收相关的基因，如胰凝乳蛋白酶原B1（Ctrb1）、胰蛋白酶原（Prss1）、胰蛋白酶（Tyr5、Tyr4）、羧肽酶A1（Cpa1）及胰凝乳蛋白酶样弹性蛋白酶家族成员3b（Cela3b），在KSR23小鼠肠道中均呈下调表达。转录组分析还显示，参与极低密度脂蛋白（very low-density lipoprotein, VLDL）颗粒通路调控的多个基因表达水平降低。此类颗粒可调控脂肪与胆固醇释放入血液循环。

综上，上述结果表明，IL-23及其他细胞因子的全身性表达与肠道内调控食物加工相关基因的显著转录变化密切相关。

总体实验设计：我们采用因美纳（Illumina）Nextseq 500测序平台，通过深度测序获取了5日龄野生型（WT）与IL-23表达小鼠（KSR23）的空肠mRNA表达谱。