Swansea University Medical School, Swansea University, Swansea, UK.
Department of Animal Sciences, University of Florida, Gainesville, Florida, USA.
Reproduction. 2021 May;161(5):499-512. doi: 10.1530/REP-20-0554.
Bovine granulosa cells are often exposed to energy stress, due to the energy demands of lactation, and exposed to lipopolysaccharide from postpartum bacterial infections. Granulosa cells mount innate immune responses to lipopolysaccharide, including the phosphorylation of mitogen-activated protein kinases and production of pro-inflammatory interleukins. Cellular energy depends on glycolysis, and energy stress activates intracellular AMPK (AMP-activated protein kinase), which in turn inhibits mTOR (mechanistic target of rapamycin). Here, we tested the hypothesis that manipulating glycolysis, AMPK or mTOR to mimic energy stress in bovine granulosa cells limits the inflammatory responses to lipopolysaccharide. We inhibited glycolysis, activated AMPK or inhibited mTOR in granulosa cells isolated from 4-8mm and from > 8.5 mm diameter ovarian follicles, and then challenged the cells with lipopolysaccharide and measured the production of interleukins IL-1α, IL-1β, and IL-8. We found that inhibiting glycolysis with 2-deoxy-d-glucose reduced lipopolysaccharide-stimulated IL-1α > 80%, IL-1β > 90%, and IL-8 > 65% in granulosa cells from 4-8 mm and from > 8.5 mm diameter ovarian follicles. Activating AMPK with AICAR also reduced lipopolysaccharide-stimulated IL-1α > 60%, IL-1β > 75%, and IL-8 > 20%, and shortened the duration of lipopolysaccharide-stimulated phosphorylation of the mitogen-activated protein kinase ERK1/2 and JNK. However, only the mTOR inhibitor Torin 1, and not rapamycin, reduced lipopolysaccharide-stimulated IL-1α and IL-1β. In conclusion, manipulating granulosa cell energy metabolism with a glycolysis inhibitor, an AMPK activator, or an mTOR inhibitor, limited inflammatory responses to lipopolysaccharide. Our findings imply that energy stress compromises ovarian follicle immune defences.
牛颗粒细胞经常处于能量应激状态,这是由于泌乳的能量需求,以及产后细菌感染的脂多糖。颗粒细胞对脂多糖产生固有免疫反应,包括丝裂原活化蛋白激酶的磷酸化和促炎白细胞介素的产生。细胞能量依赖于糖酵解,能量应激激活细胞内 AMPK(AMP 激活的蛋白激酶),后者反过来抑制 mTOR(雷帕霉素的靶蛋白)。在这里,我们检验了这样一个假设,即操纵糖酵解、AMPK 或 mTOR 以模拟牛颗粒细胞的能量应激会限制对脂多糖的炎症反应。我们在 4-8mm 和>8.5mm 直径的卵巢卵泡中分离出颗粒细胞,抑制糖酵解、激活 AMPK 或抑制 mTOR,然后用脂多糖刺激细胞,并测量白细胞介素 IL-1α、IL-1β 和 IL-8 的产生。我们发现,用 2-脱氧-D-葡萄糖抑制糖酵解,使 4-8mm 和>8.5mm 直径的卵巢卵泡颗粒细胞中的脂多糖刺激的 IL-1α 降低>80%,IL-1β 降低>90%,IL-8 降低>65%。用 AICAR 激活 AMPK 也使脂多糖刺激的 IL-1α 降低>60%,IL-1β 降低>75%,IL-8 降低>20%,并缩短了丝裂原活化蛋白激酶 ERK1/2 和 JNK 的磷酸化的脂多糖刺激的持续时间。然而,只有 mTOR 抑制剂 Torin 1,而不是 rapamycin,降低了脂多糖刺激的 IL-1α 和 IL-1β。总之,用糖酵解抑制剂、AMPK 激活剂或 mTOR 抑制剂操纵颗粒细胞能量代谢,限制了对脂多糖的炎症反应。我们的发现表明,能量应激会损害卵巢卵泡的免疫防御。