TY - JOUR
T1 - Hypoxia-mediated carbohydrate metabolism and transport promote early-stage murine follicle growth and survival
AU - Makanji, Yogeshwar
AU - Tagler, David J
AU - Pahnke, Jennifer E
AU - Shea, Lonnie D
AU - Woodruff, Teresa K
PY - 2014
Y1 - 2014
N2 - Oxygen tension is critical for follicle growth and metabolism, especially for early-stage follicles, where vascularity is limited. Its role and underlying mechanism in the in vitro activation and maturation of immature to ovulatory follicles is largely unknown. In this study, early secondary (110 mum) murine follicles were isolated and encapsulated in alginate hydrogels to replicate the in vivo environment of the growing/maturing follicle. Encapsulated follicles were cultured for 8 days at either 2.5 or 20 O2. Survival (2.6-fold) and growth (1.2-fold) were significantly higher for follicles cultured at 2.5 compared with 20 O2. Using a mouse hypoxia-signaling pathway qRT-PCR array and GeneGo Metacore analysis, we found that direct target genes of the hypoxia-activated HIF1-complex were significantly upregulated in follicles cultured for 8 days at 2.5 compared with 20 O2, including the carbohydrate transport and metabolism genes Slc2a3, Vegfa, Slc2a1, Edn1, Pgk1, Ldha, and Hmox1. Other upregulated genes included carbohydrate transporters (Slc2a1, Slc2a3, and Slc16a3) and enzymes essential for glycolysis (Pgk1, Hmox1, Hk2, Gpi1, Pfkl, Pfkp, Aldoa, Gapdh, Pgam1, Eno1, Pkm2, and Ldha). For follicles cultured at 2.5 O2, a 7.2-fold upregulation of Vegfa correlated to an 18-fold increase in VEGFA levels, and a 3.2-fold upregulation of Ldha correlated to a 4.8-fold increase in lactate levels. Both VEGFA and lactate levels were significantly higher in follicles cultured at 2.5 compared with 20 O2. Therefore, enhanced hypoxia-mediated glycolysis is essential for growth and survival of early secondary follicles and provides vital insights into improving in vitro culture conditions.
AB - Oxygen tension is critical for follicle growth and metabolism, especially for early-stage follicles, where vascularity is limited. Its role and underlying mechanism in the in vitro activation and maturation of immature to ovulatory follicles is largely unknown. In this study, early secondary (110 mum) murine follicles were isolated and encapsulated in alginate hydrogels to replicate the in vivo environment of the growing/maturing follicle. Encapsulated follicles were cultured for 8 days at either 2.5 or 20 O2. Survival (2.6-fold) and growth (1.2-fold) were significantly higher for follicles cultured at 2.5 compared with 20 O2. Using a mouse hypoxia-signaling pathway qRT-PCR array and GeneGo Metacore analysis, we found that direct target genes of the hypoxia-activated HIF1-complex were significantly upregulated in follicles cultured for 8 days at 2.5 compared with 20 O2, including the carbohydrate transport and metabolism genes Slc2a3, Vegfa, Slc2a1, Edn1, Pgk1, Ldha, and Hmox1. Other upregulated genes included carbohydrate transporters (Slc2a1, Slc2a3, and Slc16a3) and enzymes essential for glycolysis (Pgk1, Hmox1, Hk2, Gpi1, Pfkl, Pfkp, Aldoa, Gapdh, Pgam1, Eno1, Pkm2, and Ldha). For follicles cultured at 2.5 O2, a 7.2-fold upregulation of Vegfa correlated to an 18-fold increase in VEGFA levels, and a 3.2-fold upregulation of Ldha correlated to a 4.8-fold increase in lactate levels. Both VEGFA and lactate levels were significantly higher in follicles cultured at 2.5 compared with 20 O2. Therefore, enhanced hypoxia-mediated glycolysis is essential for growth and survival of early secondary follicles and provides vital insights into improving in vitro culture conditions.
UR - http://ajpendo.physiology.org/content/ajpendo/306/8/E893.full.pdf
U2 - 10.1152/ajpendo.00484.2013
DO - 10.1152/ajpendo.00484.2013
M3 - Article
SN - 0193-1849
VL - 306
SP - 893
EP - 903
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 8
ER -