Biology subjects

Rosario, S. R.

Publications and source records attributed to Rosario, S. R..

5 recordsLinked to original sources

bioRxiv2023

Deoxyhypusine synthase is required for the translational regulation of pancreatic beta cell maturation

As professional secretory cells, beta cells require adaptable mRNA translation to facilitate a rapid synthesis of proteins, including insulin, in response to changing metabolic cues. Specialized mRNA translation programs are essential drivers of cellular development and differentiation. However, in the pancreatic beta cell, the majority of factors identified to promote growth and development function primarily at the level of transcription. Therefore, despite its importance, the regulatory role of mRNA translation in the formation and maintenance of functional beta cells is not well defined. In this study, we have identified a translational regulatory mechanism in the beta cell driven by the specialized mRNA translation factor, eukaryotic initiation factor 5A (eIF5A), which facilitates beta cell maturation. The mRNA translation function of eIF5A is only active when it is post-translationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS). We have discovered that the absence of beta cell DHPS in mice reduces the synthesis of proteins critical to beta cell identity and function at the stage of beta cell maturation, leading to a rapid and reproducible onset of diabetes. Therefore, our work has revealed a gatekeeper of specialized mRNA translation that permits the beta cell, a metabolically responsive secretory cell, to maintain the integrity of protein synthesis necessary during times of induced or increased demand. ARTICLE HIGHLIGHTSO_LIPancreatic beta cells are professional secretory cells that require adaptable mRNA translation for the rapid, inducible synthesis of proteins, including insulin, in response to changing metabolic cues. Our previous work in the exocrine pancreas showed that development and function of the acinar cells, which are also professional secretory cells, is regulated at the level of mRNA translation by a specialized mRNA translation factor, eIF5AHYP. We hypothesized that this translational regulation, which can be a response to stress such as changes in growth or metabolism, may also occur in beta cells. C_LIO_LIGiven that the mRNA translation function of eIF5A is only active when the factor is post-translationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS), we asked the question: does DHPS/eIF5AHYP regulate the formation and maintenance of functional beta cells? C_LIO_LIWe discovered that in the absence of beta cell DHPS in mice, eIF5A is not hypusinated (activated), which leads to a reduction in the synthesis of critical beta cell proteins that interrupts pathways critical for identity and function. This translational regulation occurs at weaning age, which is a stage of cellular stress and maturation for the beta cell. Therefore without DHPS/eIF5AHYP, beta cells do not mature and mice progress to hyperglycemia and diabetes. C_LIO_LIOur findings suggest that secretory cells have a mechanism to regulate mRNA translation during times of cellular stress. Our work also implies that driving an increase in mRNA translation in the beta cell might overcome or possibly reverse the beta cell defects that contribute to early dysfunction and the progression to diabetes. C_LI

developmental biology↗

bioRxiv2023

Integrated single-cell analysis defines the epigenetic basis of castration-resistant prostate luminal cells

Understanding prostate response to castration and androgen receptor signaling inhibitors (ARSI) is critical to improving long-term prostate cancer (PCa) patient survival. Here we use a multi-omics approach on 229,794 single cells to create a mouse single-cell reference atlas better suited to interpreting mouse prostate biology and castration response. Our reference atlas refines single-cell annotations and provides chromatin context, which, when coupled with mouse lineage tracing demonstrates that the castration-resistant luminal cells are distinct from the pre-existent urethra- proximal stem/progenitor cells. Molecular pathway analysis and therapeutic studies further implicate JUN/FOS, WNT/{beta}-Catenin, FOXQ1, NF{kappa}B, and JAK/STAT pathways as the major drivers of castration- resistant luminal populations with high relevance to human PCa. Importantly, we demonstrate the utility of our datasets, which can be explored through an interactive portal (https://visportal.roswellpark.org/data/tang/), to aid in developing novel combination treatments with ARSI for advanced PCa patients. O_FIG O_LINKSMALLFIG WIDTH=164 HEIGHT=200 SRC="FIGDIR/small/530998v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@8bd384org.highwire.dtl.DTLVardef@1ebc004org.highwire.dtl.DTLVardef@8b4dbforg.highwire.dtl.DTLVardef@19d7052_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

Racial differences in androgen metabolism and receptor signaling in prostate cancer

Dihydrotestosterone (DHT) and testosterone (T) mediated androgen receptor (AR) nuclear translocation initiates transcription of AR target genes that are pivotal for prostate cancer (PrCa) development and progression. Here we provide data indicating that in contrast to European American (EA) men, African American (AA) men with localized PrCa can exploit an alternative progesterone-androsterone-5-androstanedione pathway for DHT biosynthesis. Enzymes that are involved in alternate pathways of DHT biosynthesis are elevated in PrCa tissues from AA men, compared to EA men, and also correlated with increased serum DHT levels. In addition, higher serum DHT levels reflect increased RNA expression of AR target genes in PrCa tissues from AA men. Interestingly, serum T but not DHT levels are significantly lower in AA men compared to EA men with PrCa. Furthermore, serum progesterone and related intermediate metabolites levels that are produced during alternate pathways of DHT biosynthesis are significantly lower in AA men with PrCa and associated with a shorter time to disease progression. These data highlight that androgen biosynthesis is altered in therapy naive localized PrCa in AA men, and can potentially serve as prognostic indicators of disease progression. SignificanceOur work provides a rationale to examine potential pharmacological interventions that target androgen biosynthesis and AR signaling earlier in the disease continuum in AA men with PrCa. Additionally, our study lays the groundwork for developing serum measurements of intermediate androgen metabolites as PrCa prognostic biomarkers. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=147 SRC="FIGDIR/small/437727v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@932dd0org.highwire.dtl.DTLVardef@a4cca0org.highwire.dtl.DTLVardef@1764be4org.highwire.dtl.DTLVardef@1708a63_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2020

Reduced NCOR2 expression accelerates androgen deprivation therapy failure in prostate cancer

NCOR2 is frequently and significantly mutated in late stage androgen deprivation therapy resistant prostate cancer (ADT-RPCa). NCOR2 has been characterized as a transcriptional corepressor and has mechanistic links to DNA methylation, but its global functions and overall contributions to PCa progression remain enigmatic. In the current study, we utilize immunohistochemical staining of samples from over 700 PCa patients and reveal associations of reduced NCOR2 expression with correlates of aggressive primary PCa and recurrence in patients who received adjuvant androgen deprivation therapy. We mapped the dihydrotestosterone (DHT) dependent and independent effects of NCOR2 on the transcriptome, cistrome and DNA methylome in androgen sensitive (AS) and ADT-RPCa cells using the isogenic LNCaP and LNCaP-C4-2 (C4-2) cell models. Transcriptional profiling identified androgen dependent and independent regulatory roles of NCOR2, the latter of which was enhanced in the ADT-RPCa state and included neuronal differentiation. Interestingly, reduced expression of NCOR2 resulted in a striking global DNA hypermethylation pattern that significantly enriched at enhancer regions. ChIP-seq revealed that NCOR2 was more clearly associated with promoters in AS LNCaP cells, which was modestly enhanced by DHT treatment. However, in ADT-RPCa C4-2 cells, the NCOR2 cistrome was larger and more distal. Motif analyses and integration of large-scale public cistrome data revealed strong enrichment for FOXA1 in mediating NCOR2 binding, and included additional factors such as AR, E2F, TET2, MED1 and MBD2. Utilizing the CWR22 xenograft model, we demonstrate a direct role for NCOR2 in PCa progression as reduced NCOR2 expression attenuated the impact of ADT, and significantly accelerated recurrence of disease. Transcriptomic analyses in recurrent CWR22 tumors indicated NCOR2-dependent gene expression profiles during ADT that were enriched for neuroendocrine associated genes and also associated with worse survival in human patients with ADT-RPCa. DNA methylation profiles in CWR22 tumors with reduced NCOR2 expression recapitulated the hypermethylation observed in vitro, and further revealed that hypermethylation patterns are commonly associated with ADT-RPCa disease, which was also confirmed in human samples. These studies reveal robust roles for NCOR2 in regulating the PCa transcriptome and epigenome and underscore recent mutational studies linking NCOR2 loss of function to PCa disease progression.Competing Interest StatementThe authors have declared no competing interest.View Full Text

cancer biology↗

bioRxiv2018

Pan-cancer analysis of transcriptional metabolic dysregulation using The Cancer Genome Atlas

Understanding the levels of metabolic dysregulation in different disease settings is vital for the safe and effective incorporation of metabolism-targeted therapeutics in the clinic. Using transcriptomic data from 10,704 tumor and normal samples from The Cancer Genome Atlas, across 26 disease sites, we developed a novel bioinformatics pipeline that distinguishes tumor from normal tissues, based on differential gene expression for 114 metabolic pathways. This pathway dysregulation was confirmed in separate patient populations, further demonstrating the robustness of this approach. A bootstrapping simulation was then applied to assess whether these alterations were biologically meaningful, rather than expected by chance. We provide distinct examples of the types of analysis that can be accomplished with this tool to understand cancer specific metabolic dysregulation, highlighting novel pathways of interest in both common and rare disease sites. Utilizing a pathway mapping approach to understand patterns of metabolic flux, differential drug sensitivity, can accurately be predicted. Further, the identification of Master Metabolic Transcriptional Regulators, whose expression was highly correlated with pathway gene expression, explains why metabolic differences exist in different disease sites. We demonstrate these also have the ability to segregate patient populations and predict responders to different metabolism-targeted therapeutics.

bioinformatics↗