Prenatal androgen excess alters the uterine peroxisome proliferator-activated receptor (PPAR) system
REPRODUCTION FERTILITY AND DEVELOPMENT
Authors: Ferreira, Silvana R.; Velez, Leandro M.; Heber, Maria F.; Abruzzese, Giselle A.; Motta, Alicia B.
Abstract
It is known that androgen excess induces changes in fetal programming that affect several physiological pathways. Peroxisome proliferator-activated receptors (PPARs) alpha, delta and gamma are key mediators of female reproductive functions, in particular in uterine tissues. Thus, we aimed to study the effect of prenatal hyperandrogenisation on the uterine PPAR system. Rats were treated with 2mg testosterone from Day 16 to 19 of pregnancy. Female offspring (PH group) were followed until 90 days of life, when they were killed. The PH group exhibited an anovulatory phenotype. We quantified uterine mRNA levels of PPAR alpha (Ppara), PPAR delta (Ppard), PPAR gamma (Pparg), their regulators peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Ppargc1a) and nuclear receptor co-repressor 1 (Ncor1) and cyclo-oxygenase (COX)-2 (Ptgs2), and assessed the lipid peroxidation (LP) index and levels of glutathione (GSH) and prostaglandin (PG) E-2. The PH group showed decreased levels of all uterine PPAR isoforms compared with the control group. In addition, PGE(2) and Ptgs2 levels were increased in the PH group, which led to a uterine proinflammatory environment, as was LP, which led to a pro-oxidant status that GSH was not able to compensate for. These results suggest that prenatal exposure to androgen excess has a fetal programming effect that affects the gene expression of PPAR isoforms, and creates a misbalanced oxidant-antioxidant state and a proinflammatory status.
Ciliogenesis is reciprocally regulated by PPARA and NR1H4/FXR through controlling autophagy in vitro and in vivo
AUTOPHAGY
Authors: Liu, Zhi-qiang; Lee, Joon No; Son, Myeongjoo; Lim, Jae-Young; Dutta, Raghbendra Kumar; Maharjan, Yunash; Kwak, SeongAe; Oh, Goo Taeg; Byun, Kyunghee; Choe, Seong-Kyu; Park, Raekil
Abstract
The primary cilia are evolutionarily conserved microtubule-based cellular organelles that perceive metabolic status and thus link the sensory system to cellular signaling pathways. Therefore, ciliogenesis is thought to be tightly linked to autophagy, which is also regulated by nutrient-sensing transcription factors, such as PPARA (peroxisome proliferator activated receptor alpha) and NR1H4/FXR (nuclear receptor subfamily 1, group H, member 4). However, the relationship between these factors and ciliogenesis has not been clearly demonstrated. Here, we present direct evidence for the involvement of macroautophagic/autophagic regulators in controlling ciliogenesis. We showed that activation of PPARA facilitated ciliogenesis independently of cellular nutritional states. Importantly, PPARA-induced ciliogenesis was mediated by controlling autophagy, since either pharmacological or genetic inactivation of autophagy significantly repressed ciliogenesis. Moreover, we showed that pharmacological activator of autophagy, rapamycin, recovered repressed ciliogenesis in ppara(-/-) cells. Conversely, activation of NR1H4 repressed cilia formation, while knockdown of NR1H4 enhanced ciliogenesis by inducing autophagy. The reciprocal activities of PPARA and NR1H4 in regulating ciliogenesis were highlighted in a condition where de-repressed ciliogenesis by NR1H4 knockdown was further enhanced by PPARA activation. The in vivo roles of PPARA and NR1H4 in regulating ciliogenesis were examined in greater detail in ppara(-/-) mice. In response to starvation, ciliogenesis was facilitated in wild-type mice via enhanced autophagy in kidney, while ppara(-/-) mice displayed impaired autophagy and kidney damage resembling ciliopathy. Furthermore, an NR1H4 agonist exacerbated kidney damage associated with starvation in ppara(-/-) mice. These findings indicate a previously unknown role for PPARA and NR1H4 in regulating the autophagy-ciliogenesis axis in vivo.