Biology subjects

De Jesus, D. F.

Publications and source records attributed to De Jesus, D. F..

5 recordsLinked to original sources

bioRxiv2023

m6A mRNA Methylation Regulates Early Pancreatic β-Cell Differentiation

N6-methyladenosine (m6A) is the most abundant chemical modification in mRNA, and plays important roles in human and mouse embryonic stem cell pluripotency, maintenance, and differentiation. We have recently reported, for the first time, the role of m6A in the postnatal control of {beta}-cell function in physiological states and in Type 1 and 2 Diabetes. However, the precise mechanisms by which m6A acts to regulate the development of human and mouse {beta}-cells are unexplored. Here, we show that the m6A landscape is dynamic during human pancreas development, and that METTL14, one of the m6A writer complex proteins, is essential for the early differentiation of both human and mouse {beta}-cells.

developmental biology↗

bioRxiv2023

m6A mRNA Methylation in Brown Adipose Tissue Regulates Systemic Insulin Sensitivity via an Inter-Organ Prostaglandin Signaling Axis

Brown adipose tissue (BAT) has the capacity to regulate systemic metabolism through the secretion of signaling lipids. N6-methyladenosine (m6A) is the most prevalent and abundant post-transcriptional mRNA modification and has been reported to regulate BAT adipogenesis and energy expenditure. In this study, we demonstrate that the absence of m6A methyltransferase-like 14 (METTL14), modifies the BAT secretome to initiate inter-organ communication to improve systemic insulin sensitivity. Importantly, these phenotypes are independent of UCP1-mediated energy expenditure and thermogenesis. Using lipidomics, we identified prostaglandin E2 (PGE2) and prostaglandin F2a (PGF2a) as M14KO-BAT-secreted insulin sensitizers. Notably, circulatory PGE2 and PGF2a levels are inversely correlated with insulin sensitivity in humans. Furthermore, in vivo administration of PGE2 and PGF2a in high-fat diet-induced insulin-resistant obese mice recapitulates the phenotypes of METTL14 deficient animals. PGE2 or PGF2a improves insulin signaling by suppressing the expression of specific AKT phosphatases. Mechanistically, METTL14-mediated m6A installation promotes decay of transcripts encoding prostaglandin synthases and their regulators in human and mouse brown adipocytes in a YTHDF2/3-dependent manner. Taken together, these findings reveal a novel biological mechanism through which m6A-dependent regulation of BAT secretome regulates systemic insulin sensitivity in mice and humans. HighlightsO_LIMettl14KO-BAT improves systemic insulin sensitivity via inter-organ communication; C_LIO_LIPGE2 and PGF2a are BAT-secreted insulin sensitizers and browning inducers; C_LIO_LIPGE2 and PGF2a sensitize insulin responses through PGE2-EP-pAKT and PGF2a-FP-AKT axis; C_LIO_LIMETTL14-mediated m6A installation selectively destabilizes prostaglandin synthases and their regulator transcripts; C_LIO_LITargeting METTL14 in BAT has therapeutic potential to enhance systemic insulin sensitivity C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/542169v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@16b3393org.highwire.dtl.DTLVardef@1072ae3org.highwire.dtl.DTLVardef@190a6d7org.highwire.dtl.DTLVardef@1b98bce_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

Redox Regulation of m6A Methyltransferase METTL3 in Human β-cells Controls the Innate Immune Response in Type 1 Diabetes

Type 1 Diabetes (T1D) is characterized by autoimmune-mediated destruction of insulin-producing {beta}-cells. Several observations have renewed interest in the innate immune system as an initiator of the disease process against {beta}-cells. Here, we show that N6-Methyladenosine (m6A) is an adaptive {beta}-cell safeguard mechanism that accelerates mRNA decay of the 2-5-oligoadenylate synthetase (OAS) genes to control the antiviral innate immune response at T1D onset. m6A writer methyltransferase 3 (METTL3) levels increase drastically in human and mouse {beta}-cells at T1D onset but rapidly decline with disease progression. Treatment of human islets and EndoC-{beta}H1 cells with pro-inflammatory cytokines interleukin-1 {beta} and interferon mimicked the METTL3 upregulation seen at T1D onset. Furthermore, m6A-sequencing revealed the m6A hypermethylation of several key innate immune mediators including OAS1, OAS2, and OAS3 in human islets and EndoC-{beta}H1 cells challenged with cytokines. METTL3 silencing in human pseudoislets or EndoC-{beta}H1 cells enhanced OAS levels by increasing its mRNA stability upon cytokine challenge. Consistently, in vivo gene therapy, to prolong Mettl3 overexpression specifically in {beta}-cells, delayed diabetes progression in the non-obese diabetic (NOD) mouse model of T1D by limiting the upregulation of Oas pointing to potential therapeutic relevance. Mechanistically, the accumulation of reactive oxygen species blocked METTL3 upregulation in response to cytokines, while physiological levels of nitric oxide promoted its expression in human islets. Furthermore, for the first time to our knowledge, we show that the cysteines in position C276 and C326 in the zinc finger domain of the METTL3 protein are sensitive to S-nitrosylation (SNO) and are significant for the METTL3 mediated regulation of OAS mRNA stability in human {beta}-cells in response to cytokines. Collectively, we report that m6A regulates human and mouse {beta}-cells to control the innate immune response during the onset of T1D and propose targeting METTL3 to prevent {beta}-cell death in T1D.

molecular biology↗

bioRxiv2022

Fluorescein-based sensors to purify human α-cells for functional and transcriptomic analyses

Pancreatic -cells secrete glucagon, an insulin counter-regulatory peptide hormone critical for the maintenance of glucose homeostasis. Investigation of the function of human -cells remains a challenge due to the lack of cost-effective purification methods to isolate high-quality -cells from islets. Here, we use the reaction-based probe diacetylated Zinpyr1 (DA-ZP1) to introduce a novel and simple method for enriching live -cells from dissociated human islet cells with > 97% purity. The -cells, confirmed by sorting and immunostaining for glucagon, were cultured up to 10 days to form -pseudoislets. The -pseudoislets could be maintained in culture without significant loss of viability, and responded to glucose challenge by secreting appropriate levels of glucagon. RNA-sequencing analyses (RNA-seq) revealed that expression levels of key -cell identity genes were sustained in culture while some of the genes such as DLK1, GSN, SMIM24 were altered in -pseudoislets in a time-dependent manner. In conclusion, we report a method to sort human primary -cells with high purity that can be used for downstream analyses such as functional and transcriptional studies.

cell biology↗

bioRxiv2019

RADAR: Differential analysis of MeRIP-seq data with a random effect model

Epitranscriptome profiling using MeRIP-seq is a powerful technique for in vivo functional studies of reversible RNA modifications. We develop RADAR, a comprehensive analytical tool for detecting differentially methylated loci in MeRIP-seq data. RADAR enables accurate identification of altered methylation sites by accommodating variability of pre-immunoprecipitation expression level and post-immunoprecipitation count using different strategies. In addition, it is compatible with complex study design when covariates need to be incorporated in the analysis. Through simulation and real datasets analyses, we show that RADAR leads to more accurate and reproducible differential methylation analysis results than alternatives, which is available at https://github.com/scottzijiezhang/RADAR.

bioinformatics↗