Daily Endocrinology Research Analysis
Three impactful studies span therapy and mechanism in metabolic endocrinology: a phase II RCT shows the pan-PPAR agonist chiglitazar substantially reduces liver fat in MASLD; a mechanistic study uncovers a glucose–α-ketoglutarate–JMJD1A–ChREBP epigenetic axis driving visceral adipogenesis; and imeglimin is shown to suppress glucagon secretion via α-cell EPAC2 signaling while altering α-cell identity. Together, they advance MASLD therapeutics and deepen understanding of adipose and islet biology.
Summary
Three impactful studies span therapy and mechanism in metabolic endocrinology: a phase II RCT shows the pan-PPAR agonist chiglitazar substantially reduces liver fat in MASLD; a mechanistic study uncovers a glucose–α-ketoglutarate–JMJD1A–ChREBP epigenetic axis driving visceral adipogenesis; and imeglimin is shown to suppress glucagon secretion via α-cell EPAC2 signaling while altering α-cell identity. Together, they advance MASLD therapeutics and deepen understanding of adipose and islet biology.
Research Themes
- Therapeutic modulation of metabolic liver disease (MASLD)
- Epigenetic nutrient sensing in adipose tissue
- Islet alpha-cell signaling and glucagon regulation by antidiabetic agents
Selected Articles
1. Chiglitazar in MASLD with hypertriglyceridemia and insulin resistance: A phase II, randomized, double-blind, placebo-controlled study.
In a multicenter phase II RCT (n=104), chiglitazar reduced MRI-PDFF by 28–40% versus 3% with placebo over 18 weeks, with dose-dependent effects. Liver injury markers (ALT, AST, γ-GT) improved and safety was favorable, with trends toward better lipids, insulin resistance, and fibrosis indicators.
Impact: This high-quality RCT demonstrates robust reductions in liver fat on a quantitative imaging surrogate in MASLD with an agent targeting PPARs, advancing a promising therapeutic modality in an area of unmet need.
Clinical Implications: Supports further phase III development of chiglitazar in MASLD/MASH, suggests patient subgroups (hypertriglyceridemia with insulin resistance) may benefit, and motivates incorporation of MRI-PDFF endpoints alongside histology in trials.
Key Findings
- Chiglitazar reduced MRI-PDFF by −28.1% (48 mg) and −39.5% (64 mg) vs −3.2% with placebo at 18 weeks.
- Between-group differences vs placebo were −24.9% (p<0.05) and −36.3% (p<0.001) for 48 mg and 64 mg, respectively.
- ALT, AST, and γ-GT improved significantly; lipid parameters, insulin resistance, metabolic syndrome, and fibrosis indicators trended better.
- Both doses were well tolerated; adverse events were mostly mild to moderate.
Methodological Strengths
- Multicenter randomized double-blind placebo-controlled design with prespecified MRI-PDFF primary endpoint
- Dose-ranging evaluation with consistent biomarker improvements
Limitations
- Short duration (18 weeks) with surrogate imaging endpoints without histologic confirmation
- Selective MASLD population (hypertriglyceridemia and insulin resistance); modest sample size (n=104)
Future Directions: Conduct phase III trials with longer follow-up, histologic endpoints (NASH resolution, fibrosis), cardiovascular/metabolic outcomes, and comparative effectiveness vs other PPAR or thyroid hormone receptor agonists.
BACKGROUND AND AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) can progress to severe forms such as metabolic dysfunction-associated steatohepatitis (MASH). Effective treatments for MASH are urgently needed. This study aimed to evaluate the efficacy and safety of chiglitazar, a PPAR pan-agonist, in MASLD with hypertriglyceridemia and insulin resistance. APPROACH AND RESULTS: In this phase II multicenter, randomized, double-blind and placebo-controlled study, 104 patients with MASLD with hypertriglyceridemia and insulin resistance were randomized 2:2:1 to receive 48 mg, 64 mg of chiglitazar, or placebo once daily for 18 weeks. The primary endpoint was the percentage change in liver fat content measured by magnetic resonance imaging proton density fat fraction (MRI-PDFF) at week 18. Chiglitazar significantly reduced liver fat content, with percentage change from baseline at week 18 of -28.1% (95% CI -37.5 to -18.7) in the 48 mg group and -39.5% (95% CI -49.0 to -30.0) in the 64 mg group, compared with -3.2% (95% CI -16.8 to 10.4) in placebo group. The differences compared with placebo were -24.9% ( p <0.05) for the 48 mg group and -36.3% ( p <0.001) for the 64 mg group. Chiglitazar also significantly improved liver injury-related biomarkers such as ALT, AST, and γ-GT. Liver fibrosis indicators, lipid parameters, insulin resistance, and metabolic syndrome showed an improved trend. Both doses of chiglitazar were well tolerated, with most adverse events being mild to moderate. CONCLUSIONS: Chiglitazar significantly reduced liver fat content in MASLD with hypertriglyceridemia and insulin resistance, with a dose-dependent effect and a favorable safety profile.
2. Glucose-activated JMJD1A drives visceral adipogenesis via α-ketoglutarate-dependent chromatin remodeling.
The study delineates a glucose–α-ketoglutarate–JMJD1A–ChREBP epigenetic circuit that removes H3K9me2 at adipogenic loci and enables hyperplastic expansion of visceral fat during nutrient excess. JMJD1A deficiency shifts remodeling toward hypertrophy with inflammation, highlighting depot-specific control of adipogenesis.
Impact: Reveals a nutrient-sensitive chromatin mechanism linking glucose flux to adipose tissue expansion mode, offering tractable epigenetic targets to modulate unhealthy hypertrophy versus healthier hyperplasia.
Clinical Implications: Targeting the JMJD1A/NFIC/ChREBP axis may shift adipose remodeling away from inflammatory hypertrophy, potentially improving insulin sensitivity and cardiometabolic risk in obesity.
Key Findings
- Glucose raises nuclear α-ketoglutarate, activating JMJD1A to demethylate H3K9me2 at adipogenic loci (e.g., Pparg).
- NFIC recruits JMJD1A, enabling ChREBP binding and transcriptional activation—a feedforward nutrient–chromatin circuit.
- In vivo, JMJD1A is essential for de novo adipogenesis and hyperplastic expansion of visceral fat; deficiency causes hypertrophy and local inflammation.
Methodological Strengths
- Integrated mechanistic approach combining chromatin profiling with in vivo genetic models
- Identification of transcription factor cooperation (NFIC–ChREBP) at pre-marked promoters
Limitations
- Findings derived primarily from murine models; human depot-specific applicability remains to be confirmed
- Long-term metabolic outcomes and pharmacologic tractability of JMJD1A targeting were not assessed
Future Directions: Validate the axis in human adipose depots, define systemic consequences of modulating JMJD1A activity, and explore small-molecule or nutrient-based interventions to bias adipose remodeling.
Adipose tissue remodels via hypertrophy or hyperplasia in response to nutrient status, but the mechanisms governing these expansion modes remain unclear. Here, we identify a nutrient-sensitive epigenetic circuit linking glucose metabolism to chromatin remodeling during adipogenesis. Upon glucose stimulation, α-ketoglutarate (α-KG) accumulates in the nucleus and activates the histone demethylase JMJD1A to remove repressive histone H3 lysine 9 dimethylation (H3K9me2) marks at glycolytic and adipogenic gene loci, including Pparg. JMJD1A is recruited to pre-marked promoter chromatin via nuclear factor IC (NFIC), enabling carbohydrate-responsive element-binding protein (ChREBP) binding and transcriptional activation. This feedforward mechanism couples nutrient flux to chromatin accessibility and gene expression. In vivo, JMJD1A is essential for de novo adipogenesis and hyperplastic expansion in visceral fat under nutrient excess. JMJD1A deficiency impairs hyperplasia, exacerbates adipocyte hypertrophy, and induces local inflammation. These findings define a glucose-α-KG-JMJD1A-ChREBP axis regulating depot-specific adipogenesis and uncover a chromatin-based mechanism by which glucose metabolism governs adaptive adipose tissue remodeling.
3. Imeglimin suppresses glucagon secretion and induces a loss of α cell identity.
Imeglimin directly suppresses α-cell glucagon secretion by downregulating Gsα and limiting EPAC2-mediated secretion in response to low glucose, GIP, or adrenaline, and it induces loss of α-cell identity. The findings suggest dual implications: benefit in hyperglucagonemia but caution regarding α-cell phenotype.
Impact: Provides a clear mechanistic basis for imeglimin’s effects on α cells beyond glycemia, informing therapeutic use and safety monitoring, especially where counterregulation may be critical.
Clinical Implications: Imeglimin may mitigate hyperglucagonemia in type 2 diabetes, but clinicians should consider potential effects on α-cell identity and counterregulatory responses, especially in hypoglycemia-prone patients.
Key Findings
- Imeglimin directly suppresses glucagon secretion from α cells independent of insulin.
- Mechanism: reduced Gsα expression limits EPAC2-mediated glucagon release induced by low glucose, GIP, or adrenaline.
- Imeglimin attenuates α-cell Ca2+ signaling and induces loss of α-cell identity.
Methodological Strengths
- Mechanistic dissection across multiple α-cell stimuli (low glucose, GIP, adrenaline)
- Direct assessment of α-cell signaling (EPAC2, Ca2+) and identity markers
Limitations
- Preclinical mechanistic study; human in vivo counterregulatory effects not established
- Long-term consequences of α-cell identity changes were not assessed
Future Directions: Evaluate imeglimin’s impact on glucagon counterregulation and hypoglycemia risk in humans; clarify reversibility and functional significance of α-cell identity changes; explore patient stratification.
Dysregulated α cell function contributes to the development of diabetes. In this study, we find that treatment with imeglimin, an antidiabetic drug, prevents glucagon release and induces a loss of α cell identity through direct action on α cells. Mechanistically, imeglimin reduces Gsα expression to inhibit the exchange protein directly activated by cyclic adenosine monophosphate 2 (EPAC2)-mediated secretion of glucagon induced by low glucose, gastric inhibitory polypeptide (GIP), or adrenaline in an insulin-independent manner. Imeglimin also attenuates α cell Ca