Transcriptomic analysis of the mouse mammary gland reveals new insights for the role of serotonin in lactation

Serotonin in the mammary gland is known to regulate processes such as calcium homeostasis, tight junction permeability, and milk protein gene expression. The objective of this study was to discover novel genes, pathways and functions which serotonin modulates during lactation. The rate-limiting enzyme in the synthesis of non-neuronal serotonin is tryptophan-hydroxylase (TPH1). Therefore, we used TPH1 knock-out mice dams (serotonin deficient) and compared them to wild-type dams and also Tph1 deficient dams injected daily with 5-HTP. Mammary gland tissues were collected on day 10 of lactation and then analyzed by RNA sequencing. Genome-wide gene expression profiles of 12 mouse mammary gland samples were evaluated using RNA sequencing; these 12 samples belong to wild-type dams (WT; n = 4), Tryptophan hydroxylase (Tph1) knock-out dams (KO; Tph1 deficient; n = 4), and Tph1 deficient dams injected daily with 5-HTP (RC; n = 4). Mammary tissues were collected on day 10 of lactation and then underwent RNA extraction, library generation, and subsequent sequencing.乳腺中的血清素（serotonin）已知可调控钙稳态、紧密连接通透性及乳蛋白基因表达等生理过程。本研究旨在揭示泌乳期血清素所调控的全新基因、信号通路与生物学功能。非神经元血清素合成的限速酶为色氨酸羟化酶（tryptophan-hydroxylase, TPH1）。因此，本研究选用TPH1基因敲除母鼠（血清素缺陷型），并以野生型母鼠作为对照，同时对另一组Tph1缺陷母鼠每日注射5-HTP进行干预。研究人员于泌乳第10天采集乳腺组织，随后通过RNA测序（RNA sequencing）开展分析。本次共对12份小鼠乳腺组织样本进行全基因组基因表达谱评估，该12份样本分为三组：野生型母鼠组（WT；n = 4）、色氨酸羟化酶（Tph1）基因敲除母鼠组（KO；Tph1缺陷型；n = 4），以及每日注射5-HTP的Tph1缺陷母鼠组（RC；n = 4）。所有样本均采集自泌乳第10天的乳腺组织，后续依次完成RNA提取、文库构建及后续测序。