Key Lab of Animal Production, Product Quality and Security, Ministry of Education, Jilin Agricultural University, Jilin, Changchun, 130118, China; College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
Key Lab of Animal Production, Product Quality and Security, Ministry of Education, Jilin Agricultural University, Jilin, Changchun, 130118, China; College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
Theriogenology. 2022 Sep 1;189:118-126. doi: 10.1016/j.theriogenology.2022.06.016. Epub 2022 Jun 19.
Leydig cells are important component of testis cells, which can synthesize testosterone with free cholesterol derived from lipid droplets (LDs). It is well known that melatonin could regulate synthesis of testosterone. However, it is still unclear whether melatonin participates in the synthesis of testosterone by regulating the lipolysis of LDs in Leydig cells. The purpose of this study was to elucidate the effect of melatonin on synthesis of testosterone in roosters Leydig cells by regulating lipolysis of LDs. The results showed that melatonin decreased synthesis of testosterone and intracellular free cholesterol in roosters Leydig cells. Exogenous addition of 22-OH-Cholesterol counteracted the inhibitory effect of melatonin on synthesis of testosterone. Furthermore, melatonin increased the LDs content and expression of perilipin 1 (PLIN1), and decreased expression of hormone-sensitive lipase (HSL) and triacylglycerol hydrolase (ATGL) in roosters Leydig cells. In addition, silencing PLIN1 reversed the inhibitory effect of melatonin on synthesis of testosterone in roosters Leydig cells by increasing free cholesterol content and expression of HSL and ATGL, and decreasing the lipid droplet content. Activation of cAMP/PKA pathway by using the pathway activators Forskolin and 8-Bromo-cAMP attenuated the inhibitory effect of melatonin on synthesis of testosterone accompanied by increasing level of free cholesterol content and expression of HSL and ATGL, and decreasing level of lipid droplet content and expression of PLIN1 in roosters Leydig cells. These results suggested that melatonin could inhibit the synthesis of testosterone in roosters Leydig cells by reducing the content of intracellular free cholesterol in which expression of PLIN1 and cAMP/PKA pathway were inhibited to reduce the lipolysis of LDs.
间质细胞是睾丸细胞的重要组成部分，它可以利用从脂滴（LDs）中衍生的游离胆固醇合成睾酮。众所周知，褪黑素可以调节睾酮的合成。然而，褪黑素是否通过调节间质细胞中 LDs 的脂解参与睾酮的合成仍不清楚。本研究旨在阐明褪黑素通过调节 LDs 的脂解来影响公鸡间质细胞中睾酮的合成。结果表明，褪黑素降低了公鸡间质细胞中睾酮和细胞内游离胆固醇的合成。外源性添加 22-OH-胆固醇可拮抗褪黑素对睾酮合成的抑制作用。此外，褪黑素增加了公鸡间质细胞中 LDs 的含量和 perilipin 1（PLIN1）的表达，降低了激素敏感脂肪酶（HSL）和三酰基甘油水解酶（ATGL）的表达。此外，沉默 PLIN1 通过增加游离胆固醇含量和 HSL 和 ATGL 的表达，降低脂质滴含量，逆转了褪黑素对公鸡间质细胞中睾酮合成的抑制作用。通过使用通路激活剂 Forskolin 和 8-Bromo-cAMP 激活 cAMP/PKA 通路，伴随着游离胆固醇含量和 HSL 和 ATGL 的表达增加，以及脂质滴含量和 PLIN1 的表达降低，减弱了褪黑素对睾酮合成的抑制作用。这些结果表明，褪黑素可以通过降低细胞内游离胆固醇的含量来抑制公鸡间质细胞中睾酮的合成，其中 PLIN1 和 cAMP/PKA 通路的表达受到抑制，从而减少 LDs 的脂解。
