Antidepressants increase adult hippocampal neurogenesis in animal models, but the underlying molecular mechanisms are unknown. In this study, we used human hippocampal progenitor cells to investigate the molecular pathways involved in the antidepressant-induced modulation of neurogenesis. Because our previous studies have shown that antidepressants regulate glucocorticoid receptor (GR) function, we specifically tested whether the GR may be involved in the effects of these drugs on neurogenesis. We found that treatment (for 3-10 days) with the antidepressant, sertraline, increased neuronal differentiation via a GR-dependent mechanism. Specifically, sertraline increased both immature, doublecortin (Dcx)-positive neuroblasts (+16%) and mature, microtubulin-associated protein-2 (MAP2)-positive neurons (+26%). This effect was abolished by the GR-antagonist, RU486. Interestingly, progenitor cell proliferation, as investigated by 5'-bromodeoxyuridine (BrdU) incorporation, was only increased when cells were co-treated with sertraline and the GR-agonist, dexamethasone, (+14%) an effect which was also abolished by RU486. Furthermore, the phosphodiesterase type 4 (PDE4)-inhibitor, rolipram, enhanced the effects of sertraline, whereas the protein kinase A (PKA)-inhibitor, H89, suppressed the effects of sertraline. Indeed, sertraline increased GR transactivation, modified GR phosphorylation and increased expression of the GR-regulated cyclin-dependent kinase-2 (CDK2) inhibitors, p27(Kip1) and p57(Kip2). In conclusion, our data suggest that the antidepressant, sertraline, increases human hippocampal neurogenesis via a GR-dependent mechanism that requires PKA signaling, GR phosphorylation and activation of a specific set of genes. Our data point toward an important role for the GR in the antidepressant-induced modulation of neurogenesis in humans.
Objectives/Hypothesis Direct glucocorticoid (GC) injection for vocal fold (VF) scarring has evolved as a therapeutic strategy, but the mechanisms underlying the antifibrotic effects remain unclear. GCs act via the glucocorticoid receptor (GR), which is phosphorylated at multiple serine residues in a hormone‐dependent manner to affect bioactivity. We hypothesize that GCs regulate SMAD signaling via GR phosphorylation in vocal fold fibroblasts (VFFs). Study Design In vitro. Methods Human VFFs were treated with dexamethasone (DM; 10 −5 –10 −7 M) ± transforming growth factor (TGF)‐β1 (10 ng/mL). RU486 (10 −6 M) was employed to isolate the regulatory effects of GR. Total GR, Ser 211 , and Ser 203 phosphorylation was examined via sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and immunocytochemistry. Quantitative polymerase chain reaction was employed to determine GR‐mediated effects of DM on genes related to fibrosis. Results Total GR and Ser 211 phosphorylation was observed predominantly in the nucleus 1 hour after DM administration. DM decreased total GR expression, but Ser 203 and Ser 211 phosphorylation increased. RU486 limited the effects of DM. SMAD3 and SMAD7 mRNA expression significantly decreased 4 hours after DM administration ( P < 0.05); this response was negated by RU486. COL1A1 remained unchanged, and ACTA2 significantly increased following 24 hours of DM treatment ( P < 0.05). Conclusion DM regulated TGF‐β1 signaling via altered SMAD3 and SMAD7 expression. This response was associated with altered GR phosphorylation. These findings provide insight into the mechanisms of steroidal effects on vocal fold repair; ultimately, we seek to enhance therapeutic strategies for these challenging patients. Level of Evidence NA Laryngoscope , 129:E187–E193, 2019
<p>MPC6 inhibits AR transcriptional activity (S1); MPC6 treatment did not decrease AR protein level in prostate cancer cell lines (S2); MPC6's anti-proliferative effect in non-prostate cancer cell lines (S3); PK/PD analysis for plasma MPC6 concentration (S4); MPC6 treatment did not significantly reduce host body weight (S5).</p>
Abstract The regression, or resolution, of inflammation in atherosclerotic plaques is impaired in diabetes. However, the factors mediating this effect remain incomplete. We identified protein arginine methyltransferase 2 (PRMT2) as a protein whose expression in macrophages is reduced in hyperglycemia and diabetes. PRMT2 catalyzes arginine methylation to target proteins to modulate gene expression. Because PRMT2 expression is reduced in cells in hyperglycemia, we wanted to determine whether PRMT2 plays a causal role in the impairment of atherosclerosis regression in diabetes. We, therefore, examined the consequence of deleting PRMT2 in myeloid cells during the regression of atherosclerosis in normal and diabetic mice. Remarkably, we found significant impairment of atherosclerosis regression under normoglycemic conditions in mice lacking PRMT2 ( Prmt2 −/− ) in myeloid cells that mimic the decrease in regression of atherosclerosis in WT mice under diabetic conditions. This was associated with increased plaque macrophage retention, as well as increased apoptosis and necrosis. PRMT2-deficient plaque CD68+ cells under normoglycemic conditions showed increased expression of genes involved in cytokine signaling and inflammation compared to WT cells. Consistently, Prmt2 −/− bone marrow-derived macrophages (BMDMs) showed an increased response of proinflammatory genes to LPS and a decreased response of inflammation resolving genes to IL-4. This increased response to LPS in Prmt2 −/− BMDMs occurs via enhanced NF-kappa B activity. Thus, the loss of PRMT2 is causally linked to impaired atherosclerosis regression via a heightened inflammatory response in macrophages. That PRMT2 expression was lower in myeloid cells in plaques from human subjects with diabetes supports the relevance of our findings to human atherosclerosis.
Abstract : Androgens are hormones that play a critical role in stimulating prostate cancer growth. Androgens activate a protein called the androgen receptor (AR), which regulates genes involved in cell growth. Although powerful anti-androgen drugs can be administered to block AR action and have been used successfully to treat patients with prostate cancer, over time the tumors become resistant to the drugs, leaving few treatment options. The goal of this proposal is to develop a new approach to block AR activity and stop prostate cancer growth using a new family of molecules called multivalent peptidomimetic conjugates. To accomplish our goals, we will create a set of conjugates with anti-androgens linked to the peptidomimetic backbone at variable intervals along the molecular chain. We will test these molecules for their ability to bind to AR. Those that bind tightly will then be tested in tumor models to evaluate if they block androgen-dependent prostate cancer cell growth. To understand how these molecules block AR function, we will determine the three-dimensional structure of AR bound to the peptidomimetic conjugates. These studies will be used to guide our ability to tailor the conjugates for optimal interactions with the AR.
// Upal Basu-Roy 1,* , Eugenia Han 2,* , Kirk Rattanakorn 1 , Abhilash Gadi 1 , Narendra Verma 1 , Giulia Maurizi 1 , Preethi H. Gunaratne 3 , Cristian Coarfa 4 , Oran D. Kennedy 5 , Michael J. Garabedian 1,2 , Claudio Basilico 1,2 and Alka Mansukhani 1,2 1 Department of Microbiology, NYU School of Medicine, New York, NY, USA 2 Perlmutter Cancer Center, Langone Medical Center, New York, NY, USA 3 Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA 4 Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA 5 Department of Orthopaedic Surgery, NYU School of Medicine, New York, NY, USA * These authors have contributed equally to this work Correspondence to: Alka Mansukhani, email: // Keywords : osteosarcoma, thiazolidinediones, cancer stem cells, osteoblast lineage, adipocyte Received : July 15, 2016 Accepted : August 01, 2016 Published : August 12, 2016 Abstract Osteosarcoma (OS) is a highly aggressive pediatric bone cancer in which most tumor cells remain immature and fail to differentiate into bone-forming osteoblasts. However, OS cells readily respond to adipogenic stimuli suggesting they retain mesenchymal stem cell-like properties. Here we demonstrate that nuclear receptor PPARγ agonists such as the anti-diabetic, thiazolidinedione (TZD) drugs induce growth arrest and cause adipogenic differentiation in human, mouse and canine OS cells as well as in tumors in mice. Gene expression analysis reveals that TZDs induce lipid metabolism pathways while suppressing targets of the Hippo-YAP pathway, Wnt signaling and cancer-related proliferation pathways. Significantly, TZD action appears to be restricted to the high Sox2 expressing cancer stem cell population and is dependent on PPARγ expression. TZDs also affect growth and cell fate by causing the cytoplasmic sequestration of the transcription factors SOX2 and YAP that are required for tumorigenicity. Finally, we identify a TZD-regulated gene signature based on Wnt/Hippo target genes and PPARγ that predicts patient outcomes. Together, this work highlights a novel connection between PPARγ agonist in inducing adipogenesis and mimicking the tumor suppressive hippo pathway. It also illustrates the potential of drug repurposing for TZD-based differentiation therapy for osteosarcoma.
Dysregulation of liver X receptor alpha (LXRalpha) activity has been linked to cardiovascular and metabolic diseases. Here, we show that LXRalpha target gene selectivity is achieved by modulation of LXRalpha phosphorylation. Under basal conditions, LXRalpha is phosphorylated at S198; phosphorylation is enhanced by LXR ligands and reduced both by casein kinase 2 (CK2) inhibitors and by activation of its heterodimeric partner RXR with 9-cis-retinoic acid (9cRA). Expression of some (AIM and LPL), but not other (ABCA1 or SREBPc1) established LXR target genes is increased in RAW 264.7 cells expressing the LXRalpha S198A phosphorylation-deficient mutant compared to those with WT receptors. Surprisingly, a gene normally not expressed in macrophages, the chemokine CCL24, is activated specifically in cells expressing LXRalpha S198A. Furthermore, inhibition of S198 phosphorylation by 9cRA or by a CK2 inhibitor similarly promotes CCL24 expression, thereby phenocopying the S198A mutation. Thus, our findings reveal a previously unrecognized role for phosphorylation in restricting the repertoire of LXRalpha-responsive genes.
