Protamine lacking piscine spermatozoa are transcriptionally active

Transcriptional quiescence of post-meiotic spermatozoa associated with protamine-mediated chromatin condensation is widely recognized in animals. How sperm acquire the extratesticular maturational competence to move and fertilize the egg is therefore thought to occur via non-transcriptional mechanisms. Here, using transcriptional profiling during spermatozoon differentiation in a fish that does not condense chromatin with protamines, we uncover spatially distinct roles of the GnRH receptor and PDGF signaling pathways between the somatic epithelia of the extratesticular ducts and the maturing spermatozoa. In vitro induction and inhibition experiments demonstrate that the endocrine signaling pathways are conserved in different lineages of fish and activate de novo transcription of spermatozoon genes required for the acquisition of full motility. These experiments further confirmed that mitochondrial translation is important for sperm maturation in anamniotes as in amniotes, but that transcriptional quiescence of post-meiotic spermatozoa is not a pan vertebrate phenomenon. On the contrary, the data show that the identified signal transduction pathways between the soma and the sperm upregulate effector genes essential for maturational competence and male fertility.

Increased Phosphatase Regenerating Liver -1 Trigger Vascular Remodeling in Injured Ovary Via Platelet-derived Growth Factor Signaling Pathway

Background: Vascular abnormalities in the ovary cause infertility accompanied by ovarian insufficiency due to a microenvironment of barren ovarian tissues. placenta-derived mesenchymal stem cells (PD-MSCs, Naïve) treatment in ovarian dysfunction shows angiogenic effect, however, the therapeutic mechanism between ovarian function and vascular remodeling still unclear. Therefore, we examined whether by phosphatase regenerating liver -1 (PRL-1), which is correlated with angiogenesis in reproductive systems, overexpressed PD-MSCs could maximize the angiogenic effects in an ovarian tissues injured of rat model with partial ovariectomy and their therapeutic mechanism by enhanced vascular function via PDGF signaling.Methods: PD-MSCsPRL-1 (PRL-1) were generated by nonviral AMAXA gene delivery system and analyzed the vascular remodeling and follicular development in ovary. One week after Sprague-Dawley (SD) rats ovariectomy, Naïve and PRL-1 was transplanted. The animals were sacrificed at 1, 3 and 5 weeks after transplantation and vascular remodeling and follicular development were analyzed. Also, human umbilical vein endothelial cells (HUVECs) and ovarian explantation culture were performed to prove the specific effects and mechanism of PRL-1.Results: Vascular structures in ovarian tissues (e.g., number of vessels, thickness and lumen area) showed changes in the Naïve and PRL-1-overexpressed PD-MSC (PRL-1) transplantation (Tx) groups compared to the nontransplantation (NTx) group. Especially, PRL-1 induce to increase the expression of platelet-derived growth factor (PDGF), which plays a role in vascular remodeling as well as follicular development, compared to the NTx. Also, the expression of genes related to pericyte and vascular permeability in arteries was significantly enhanced in the PRL-1 compared to the NTx (p<0.05). PRL-1 enhanced the vascular formation and permeability of human umbilical vein endothelial cells (HUVECs) via activated the PDGF signaling pathway.Conclusions: Our results show that PRL-1 restored ovarian function by enhanced vascular function via PDGF signaling pathway. These findings offer new insight into the effects of functionally enhanced stem cell therapy for reproductive systems and should provide new avenues to develop more efficient therapies in degenerative medicine.

Targeted mutagenesis on PDGFRα-Fc identifies amino acid modifications that allow efficient inhibition of HCMV infection while abolishing PDGF sequestration

Platelet-derived growth factor receptor alpha (PDGFRα) serves as an entry receptor for the human cytomegalovirus (HCMV), and soluble PDGFRα-Fc can neutralize HCMV at a half-maximal effective concentration (EC50) of about 10 ng/ml. While this indicates a potential for usage as an HCMV entry inhibitor PDGFRα-Fc can also bind the physiological ligands of PDGFRα (PDGFs), which likely interferes with the respective signaling pathways and represents a potential source of side effects. Therefore, we tested the hypothesis that interference with PDGF signaling can be prevented by mutations in PDGFRα-Fc or combinations thereof, without losing the inhibitory potential for HCMV. To this aim, a targeted mutagenesis approach was chosen. The mutations were quantitatively tested in biological assays for interference with PDGF-dependent signaling as well as inhibition of HCMV infection and biochemically for reduced affinity to PDGF-BB, facilitating quantification of PDGFRα-Fc selectivity for HCMV inhibition. Mutation of Ile 139 to Glu and Tyr 206 to Ser strongly reduced the affinity for PDGF-BB and hence interference with PDGF-dependent signaling. Inhibition of HCMV infection was less affected, thus increasing the selectivity by factor 4 and 8, respectively. Surprisingly, the combination of these mutations had an additive effect on binding of PDGF-BB but not on inhibition of HCMV, resulting in a synergistic 260fold increase of selectivity. In addition, a recently reported mutation, Val 242 to Lys, was included in the analysis. PDGFRα-Fc with this mutation was fully effective at blocking HCMV entry and had a drastically reduced affinity for PDGF-BB. Combining Val 242 to Lys with Ile 139 to Glu and/or Tyr 206 to Ser further reduced PDGF ligand binding beyond detection. In conclusion, this targeted mutagenesis approach identified combinations of mutations in PDGFRα-Fc that prevent interference with PDGF-BB but maintain inhibition of HCMV, which qualifies such mutants as candidates for the development of HCMV entry inhibitors.

Phenotypic plasticity of ER+ breast cancer in the bone microenvironment

SummaryER+ breast cancer exhibits a strong bone-tropism in metastasis. How the bone microenvironment impacts the ER signaling and endocrine therapies remains poorly understood. Here, we discover that the osteogenic niche transiently reduces ER expression and activities specifically in bone micrometastases (BMMs), leading to endocrine resistance. This is mediated by gap junctions and paracrine FGF/PDGF signaling, which together generate a stable “memory”: cancer cells extracted from bone remain resistant to endocrine therapies for several generations. Using single cell-derived populations (SCPs), we demonstrated that this process is independent of clonal selection, and represents an EZH2-mediated epigenomic reprogramming. EZH2 drives ER+ BMMs toward a basal and stem-like state. EZH2 inhibition reverses endocrine resistance. Our data demonstrates how epigenomic adaptation to the bone microenvironment drives phenotypic plasticity of metastatic seeds and alters their therapeutic responses together with clonal selection, and provides insights into the clinical enigma of ER+ metastatic recurrences despite endocrine therapies.

EPCO-06. MOLECULAR DETERMINANTS OF EVOLUTION AND PROGNOSIS AMONG DIFFUSE LOWER GRADE ASTROCYTOMAS

Gliomas with wild type (WT) isocitrate dehydrogenase (IDH) are considerably more aggressive than those with mutant IDH. To identify putative drivers of the distinct progression trajectories of IDH WT and mutant disease, we analyzed transcriptomes of lower grade astrocytomas (LGAs; grade 2–3) with retention of 1p and 19q from The Cancer Genome Atlas (TCGA; n = 347). Compared to IDH mutant LGAs, we found that PDGF signaling was significantly enriched in IDH WT LGAs and that PDGFA was the top overexpressed gene in this pathway. We identified copy number gains of chromosome 7 in WT LGAs, and methylation of the PDGFA promoter in mutant LGAs, as candidate mechanisms for the differential expression of PDGFA. High PDGFA expression and low PDGFA promoter methylation were significantly associated with poor survival in all LGAs. We also found that PDGFA expression was positively associated with aneuploidy and extracellular matrix-related immunosuppressive features in WT LGAs, underscoring the role of PDGFA as a secreted mitogen. Finally, we show that the proportion of p53 pathway mutations increase significantly with grade in IDH WT gliomas. Taken together, our findings suggest that IDH WT LGAs evolve to higher grades, and ultimately to GBM, by progressive inactivation of the p53 pathway - functioning in concert with a background of increased PDGFA expression. These data emphasize the scope of genomic reprogramming that occurs in gliomas in relation to IDH mutations and further highlight the role of PDGFA in glioma formation, progression, and prognosis. Going forward, this work provides critical biological insight that may inspire new therapeutic strategies to suppress the transformation of IDH WT LGAs to higher-grade cancers.

Human skeletal muscle CD90+ fibro-adipogenic progenitors are associated with muscle degeneration in type 2 diabetic patients

ABSTRACTAging and type 2 diabetes mellitus (T2DM) are associated with impaired skeletal muscle function and degeneration of the skeletal muscle microenvironment. However, the origin and mechanisms underlying the degeneration are not well described in human skeletal muscle. Here we show that skeletal muscles of T2DM patients exhibit pathological degenerative remodeling of the extracellular matrix that was associated with a selective increase of a subpopulation of fibro-adipogenic progenitors (FAPs) marked by expression of THY1 (CD90) - the FAPCD90+. We identified Platelet-derived growth factor (PDGF) signaling as key regulator of human FAP biology, as it promotes proliferation and collagen production at the expense of adipogenesis, an effect accompanied with a metabolic shift towards glycolytic lactate fermentation. FAPsCD90+ showed a PDGF-mimetic phenotype, with high proliferative activity and clonogenicity, increased production of extracellular matrix production and enhanced glycolysis. Importantly, the pathogenic phenotype of T2DM FAPCD90+ was reduced by treatment with the anti-diabetic drug Metformin. These data identify PDGF-driven conversion of a sub-population of FAPs as a key event in the pathogenic accumulation of extracellular matrix in T2DM muscles.

Molecular Determinants of Prognosis and Evolution in Diffuse-Lower Grade Astrocytomas

ABSTRACTLow grade astrocytomas (LGAs) are classified based on the mutational status of the isocitrate dehydrogenase (IDH) gene. While IDH wild-type (WT) LGAs evolve rapidly to glioblastoma, mutant tumors generally have a more indolent course. To identify potential drivers of the differential progression of LGAs, we analyzed transcriptomes from The Cancer Genome Atlas. Compared to mutant LGAs, platelet-derived growth factor (PDGF) signaling is enriched in WT cases, and PDGFA is the top overexpressed gene in the pathway. Putative mechanisms for differential PDGFA expression included copy number gains of chromosome 7 in WT cases and methylation of the PDGFA promoter in mutant LGAs. Additionally, we found that high PDGFA expression is associated with aneuploidy, immunosuppressive features, and worse prognosis, and that WT LGAs use multiple means to inactivate the p53 pathway to progress to GBM. Our work highlights the contribution of PDGF gene family towards the unique behaviour of LGAs.STATEMENT OF SIGNIFICANCEThis study of gene expression in LGAs suggests that differential regulation of the PDGF pathway may underlie the different natural histories of IDH WT and IDH mutant LGAs including divergent evolutionary trajectories to GBM. This insight may inspire new therapeutic strategies to suppress the transformation of LGAs to higher-grade cancers.