Progesterone-induced Warburg Effect is Regulated by Cell-type-specific Interaction of Progesterone Receptor Membrane Component 1 and Hexokinases

Background: Progesterone receptor membrane component 1 (PGRMC1) is a non-canonical progesterone (P4) binding protein. PGRMC1 is elevated in a variety of cancers and its phosphorylation state associated with hormone responsiveness in breast cancer. Metabolic reprogramming is a key factor for tumor growth during malignancies. Recently, we reported that the P4-inducedWarburg effectinHEK293cells is associated with altered post-translational modifications (PTMs) of PGRMC1, including phosphorylation, SUMOylation, and ubiquitination, which were linked to rapid proteasomal degradation of the protein. The previous study also identified hexokinase (HK) as a potential novel interacting partner of PGRMC1. HKs catalyze the first essential step of glucose metabolism and directly couple glycolysis to mitochondrial respiration. Therefore, in the present study, P4’s effects on glycolysis and PTMs of PGRMC1 as well as its interaction with HKs were compared between HEK293 and HepG2 cells to unravel the signaling pathways that mediate cell-type-specific metabolic reprogramming.Methods: P4-induced glucose metabolism in wild-type and PGRMC1-deficient cells wasassessed using the Seahorse flux analyzer, while PTMs of PGRMC1/HKs and protein-protein interaction were studied using immunoprecipitation, isoelectric focussing, phosphomimetics, and mass spectrometry.Translocation of HKs to different subcellular organelles were studied using subcellular fractionation, and the cell-type-specific effect of PGRMC1-deficiency on endoplasmic reticulum (ER) and mitochondria; ultrastructure were examined by electron microscopy. Results:P4 treatment caused a rapid increase in glycolysis in HEK293 cells, whereas it decreased glycolysis in HepG2 cells. In addition, PGRMC1 was not degraded in HepG2 cells which is in contrast to HEK293 cells where rapid proteasomal degradation of PGRMC1 occurredfollowing P4 treatment. Besides, PGRMC1 half-life and PTMs under basal condition were found cell-type-specific and the P4-induced PTMsdiffered between the two cell types. Furthermore, we observed cell-type-specific interaction of HKs with PGRMC1, and differential translocation of HK1/2 to the ER, mitochondria and nuclear compartments following P4 treatment. PGRMC1 deficiency altered ER structure in HepG2 cells. Thus, multiple factors underlying the cell-type-specific P4-PGRMC1-mediated metabolic reprogrammingwere identified. Conclusions: These findings provide a hitherto unknown novel P4-induced cell-type-specific PGRMC1-HK signaling mechanism that contributes to the molecular basis of P4-induced metabolic reprogramming, with important applications for hormone responsiveness in cancer.

Protein Tyrosine Phosphatase 1B Regulates MicroRNA-208b-Argonaute 2 Association and Thyroid Hormone Responsiveness in Cardiac Hypertrophy

ABSTRACTElevated reactive oxygen species (ROS) production plays an important role in the pathogenesis of several diseases, including cardiac hypertrophy. While the regulation of diverse sources of ROS is well characterized in the heart, the redox-sensitive targets that contribute to redox signaling remain largely undefined. We now report that protein tyrosine phosphatase 1B (PTP1B) is reversibly oxidized and inactivated in hearts undergoing hypertrophy and that gene deletion of PTP1B in mouse hearts cause an hypertrophic phenotype that is critically exacerbated in mice subjected to pressure overload. Furthermore, we show that PTP1B dephosphorylates Tyr393 on argonaute 2, a key component of the RNA-induced silencing complex, and sustains gene silencing in the heart. Our results indicate that PTP1B inactivation and argonaute 2 Tyr393 phosphorylation specifically prevents argonaute 2 from interacting with miR-208b. Phosphorylation and inactivation of argonaute 2 in PTP1B cKO mice revealed a mechanism by which defective miR-208b-mediated repression of thyroid hormone receptor-associated protein 1 (THRAP1/MED13) contributes to thyroid hormone-mediated cardiac hypertrophy. In support of this conclusion, inhibiting the synthesis of triiodothyronine (T3), using propylthiouracil, rescued TAC-induced hypertrophy and improved myocardial contractility and systolic function in PTP1B cKO mice. Together, our data illustrate that PTP1B activity exerts a cardioprotective effect in the heart and that redox signaling is tightly linked to thyroid hormone responsiveness and to microRNA-mediated gene silencing in pathological hypertrophy.

Androgen and Oestrogen Affect the Expression of Long Non-Coding RNAs During Phallus Development in a Marsupial

There is increasing evidence that long non-coding RNAs (lncRNAs) are important for normal reproductive development, yet very few lncRNAs have been identified in phalluses so far. Unlike eutherians, phallus development in the marsupial tammar wallaby occurs post-natally, enabling manipulation not possible in eutherians in which differentiation occurs in utero. We treated with sex steroids to determine the effects of androgen and oestrogen on lncRNA expression during phallus development. Hormonal manipulations altered the coding and non-coding gene expression profile of phalluses. We identified several predicted co-regulatory lncRNAs that appear to be co-expressed with the hormone-responsive candidate genes regulating urethral closure and phallus growth, namely IGF1, AR and ESR1. Interestingly, more than 50% of AR-associated coding genes and lncRNAs were also associated with ESR1. In addition, we identified and validated three novel co-regulatory and hormone-responsive lncRNAs: lnc-BMP5, lnc-ZBTB16 and lncRSPO4. Lnc-BMP5 was detected in the urethral epithelium of male phalluses and was downregulated by oestrogen in males. Lnc-ZBTB16 was downregulated by oestrogen treatment in male phalluses at day 50 post-partum (pp). LncRSPO4 was downregulated by adiol treatment in female phalluses but increased in male phalluses after castration. Thus, the expression pattern and hormone responsiveness of these lncRNAs suggests a physiological role in the development of the phallus.