Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Department of Animal Sciences, University of Florida, Gainesville, Fl, 32608, USA.
Sci Rep. 2021 May 6;11(1):9665. doi: 10.1038/s41598-021-88443-w.
In mammals, peripheral serotonin is involved in regulating energy balance. Herein, we characterized the transcriptomic profile and microstructure of adipose and muscle in pre-weaned calves with increased circulating serotonin. Holstein bull calves (21 ± 2 days old) were fed milk replacer supplemented with saline (CON, 8 mL/day n = 4) or 5-hydroxytryptophan (5-HTP, 90 mg/day, n = 4) for 10 consecutive days. Calves were euthanized on d10 to harvest adipose and muscle for RNA-Sequencing and histological analyses. Twenty-two genes were differentially expressed in adipose, and 33 in muscle. Notably, Interferon gamma inducible protein-47 was highly expressed and upregulated in muscle and adipose (avg. log FC = 6.5). Enriched pathways in adipose tissue revealed serotonin's participation in lipid metabolism and PPAR signaling. In muscle, enriched pathways were related to histone acetyltransferase binding, Jak-STAT signaling, PI3K-Akt signaling and cell proliferation. Supplementation of 5-HTP increased cell proliferation and total cell number in adipose and muscle. Adipocyte surface area was smaller and muscle fiber area was not different in the 5-HTP group. Manipulating the serotonin pathway, through oral supplementation of 5-HTP, influences signaling pathways and cellular processes in adipose and muscle related to endocrine and metabolic functions which might translate into improvements in calf growth and development.
在哺乳动物中，外周血清素参与调节能量平衡。在此，我们描述了循环血清素升高的新生小牛脂肪和肌肉的转录组图谱和微观结构。荷斯坦公牛小牛（21±2 天龄）连续 10 天用补充盐水（CON，每天 8 毫升，n=4）或 5-羟色氨酸（5-HTP，每天 90 毫克，n=4）的代乳料喂养。小牛在第 10 天被安乐死，以收获脂肪和肌肉进行 RNA 测序和组织学分析。22 个基因在脂肪中差异表达，33 个基因在肌肉中差异表达。值得注意的是，干扰素γ诱导蛋白-47在肌肉和脂肪中高度表达且上调（平均 log FC=6.5）。脂肪组织中富集的途径表明血清素参与脂质代谢和 PPAR 信号转导。在肌肉中，富集的途径与组蛋白乙酰转移酶结合、Jak-STAT 信号转导、PI3K-Akt 信号转导和细胞增殖有关。5-HTP 的补充增加了脂肪和肌肉中细胞增殖和总细胞数。5-HTP 组的脂肪细胞表面积较小，肌肉纤维面积无差异。通过口服补充 5-HTP 来操纵血清素途径，影响与内分泌和代谢功能相关的脂肪和肌肉中的信号通路和细胞过程，这可能转化为改善小牛的生长和发育。
