Daily Endocrinology Research Analysis
Analyzed 108 papers and selected 3 impactful papers.
Summary
Analyzed 108 papers and selected 3 impactful articles.
Selected Articles
1. Proteinase 3 Drives Murine Diabetic Kidney Disease by Mediating Caspase-3-dependent Apoptosis of Podocytes.
In multiple DKD mouse models, PR3 was upregulated in podocytes and drove caspase-3–dependent apoptosis, leading to proteinuria and glomerular injury. Genetic deletion of PR3 (global or podocyte-specific) and therapeutic inhibition via elafin reduced podocyte loss and DKD traits, positioning PR3 as a tractable target in diabetic nephropathy.
Impact: Identifies a previously underappreciated protease as a mechanistic driver of podocyte apoptosis in DKD and demonstrates therapeutic rescue in vivo, opening a new target class for diabetic complications.
Clinical Implications: PR3 pathway inhibition (e.g., by elafin or small-molecule inhibitors) could be developed to protect podocytes and slow DKD progression, complementing glycemic and hemodynamic control.
Key Findings
- PR3 expression increases in podocytes in murine DKD and promotes caspase-3 cleavage and apoptosis.
- Global and podocyte-specific PR3 knockout mice exhibit reduced proteinuria, mesangial expansion, and podocyte injury under diabetic stress.
- Kidney-targeted overexpression of elafin suppresses PR3 activity and attenuates podocyte loss and DKD-like traits.
- PR3 overexpression potentiates apoptosis in cultured murine podocytes; PR3 deficiency protects against adriamycin-induced podocytopathy.
Methodological Strengths
- Convergent evidence from global and cell-specific knockouts, gain-of-function, and pharmacologic inhibition.
- Use of combined DKD induction and kidney-targeted gene therapy to test causality and therapeutic potential.
Limitations
- Findings are preclinical; lack of human renal tissue validation and clinical biomarker data.
- Long-term safety and specificity of PR3 inhibition (e.g., elafin delivery) were not assessed.
Future Directions: Validate PR3 elevation and activity in human DKD kidneys, develop selective PR3 inhibitors or delivery strategies, and evaluate renal and systemic safety in large-animal models before early-phase trials.
INTRODUCTION: Podocytes play a pivotal role in maintaining homeostasis of the glomerular filtration barrier. Podocyte loss represents a critical event that contributes to the development of diabetic kidney disease (DKD). Nonetheless the key mediators and mechanisms underlying DKD-associated podocyte death remain poorly characterized. Proteinase 3 (PR3) is a serine protease with selective high abundance in myeloid cells and pleiotropic effects on the regulation of innate immunity. METHODS: An experimental DKD model was induced by a combination strategy of uninephrectomy, intraperitoneal injection of streptozocin, and feeding of a high-fat diet in global or podocyte-specific PR3 knockout mice and their controls. Mouse primary podocytes lacking PR3 or conditionally immortalized murine podocytes overexpressing PR3 were incubated with high glucose to trigger apoptosis. Adeno-associated viruses expressing the serine protease inhibitor elafin were injected locally into mouse kidney to inhibit kidney PR3. RESULTS: PR3 abundance in the kidney was markedly increased, predominantly in podocytes, in mouse models of DKD. Global or podocyte-specific genetic ablation of PR3 significantly attenuated severe proteinuria, mesangial matrix expansion, and podocyte injury in diabetic mice. Mechanistically, the lysates from mouse primary podocytes with high glucose-elicited PR3 enrichment and enhanced enzymatic activity induced cleavage of procaspase-3 and triggered podocyte apoptosis that was substantially alleviated in the presence of genetic ablation or pharmacological inhibition of PR3. Adenovirus-mediated overexpression of PR3 markedly potentiated caspase-3 cleavage and cell apoptosis in conditionally immortalized murine podocytes. In contrast, a lack of PR3 protected against adriamycin-induced podocytopathy in mice, further confirming PR3 as a driving force of podocyte injury. Therapeutically, kidney overexpression of elafin significantly attenuated podocyte loss and other DKD-like traits in mice. CONCLUSION: Our results demonstrate that podocyte-derived PR3 induces caspase-3 cleavage to mediate podocyte apoptosis, thereby potentiating DKD progression, suggesting that pharmacological intervention of podocyte-derived PR3 may represent a promising therapeutic strategy for DKD.
2. Short-term sleep restriction in humans alters diurnal circulating metabolite profiles, including those of microbial origin.
In a randomized crossover study with controlled meals, 3 nights of sleep restriction (4.5 h/night) altered 24-hour serum metabolite profiles versus normal sleep, disrupting the rhythmicity of key microbe-derived metabolites (e.g., butyrate, indole-3-propionic acid) and inducing new rhythms in kynurenine and lipid intermediates. These data reveal sleep-dependent rhythmicity of circulating microbial metabolites.
Impact: Links sleep patterns to diurnal rhythms of microbe-derived metabolites in humans under controlled feeding, providing mechanistic insight and candidate biomarkers for sleep loss–related metabolic risk.
Clinical Implications: Short sleep may perturb metabolite rhythms relevant to metabolic disease risk; microbe-derived metabolites could serve as biomarkers or intervention targets in sleep and metabolic health programs.
Key Findings
- Three nights of sleep restriction (4.5 h/night) significantly altered the composition of 24-hour serum metabolite profiles versus habitual sleep.
- Rhythmicity of microbe-derived metabolites (butyrate, indole-3-propionic acid) was lost under sleep restriction despite identical meal timing and calories.
- New diurnal rhythms emerged in kynurenine and lipid metabolism intermediates under sleep restriction.
- Findings support sleep-dependent regulation of circulating microbial metabolites independent of feeding schedule.
Methodological Strengths
- Randomized crossover design with controlled meal timing and caloric intake.
- Untargeted LC-MS metabolomics with rigorous rhythmicity assessment (JTK_CYCLE).
Limitations
- Small sample size (n=9) limits generalizability and subgroup analyses.
- Short intervention duration; no direct gut microbiome sequencing was reported to link taxa with metabolite rhythms.
Future Directions: Integrate microbiome sequencing with metabolomics in larger, diverse cohorts; test behavioral or pharmacologic interventions to restore metabolite rhythmicity and assess metabolic outcomes.
BACKGROUNDGut microbes and their metabolites contribute to the host circulating metabolome and exhibit diurnal variation influenced by sleep-wake cycles and meal timing. Sleep deprivation alters the rhythmic circulating metabolome, but its impact on microbial metabolites remains unclear. We tested whether 24-hour circulating metabolite profiles, including those of microbial origin, differ under normal (habitual) versus short-term restricted sleep.METHODSIn a randomized crossover design, 9 healthy adults completed 2 in-lab 24-hour blood sampling sessions (q120): one following 3 nights of normal sleep (8.5 hours/night), the other following 3 nights of sleep restriction (4.5 hours/night). Meal timing and caloric intake were held constant. Serum metabolites were characterized using untargeted reverse-phase liquid chromatography-mass spectrometry and rhythmicity was assessed using empirical JTK_CYCLE analysis.RESULTSWe identified 90 metabolites, including 14 of microbial origin or derived from host metabolism of microbial products, e.g., butyrate and tryptophan derivatives. Sleep restriction significantly altered serum metabolite composition compared with normal sleep. While many compounds maintained rhythmicity across conditions, sleep restriction disrupted rhythms of several key compounds, including microbe-derived metabolites. Notably, butyrate and indole-3-propionic acid lost rhythmicity, whereas new rhythms emerged in the tryptophan catabolite, kynurenine, and lipid metabolism intermediates.CONCLUSIONWe provide evidence that microbial metabolites are detectable in human blood and exhibit sleep-dependent rhythmicity. Sleep restriction alters diurnal circulating microbial and host-derived metabolite rhythms even under constant meal timing, composition, and calories. These findings support links between host sleep patterns and gut microbial metabolism and suggest microbial metabolites as potential biomarkers or mediators of sleep loss-associated health risks.TRIAL REGISTRATIONNCT00989976.FUNDINGNIH/NCRR KL2RR025000; R56DK102872-01A1, P30DK020595; P30DK042086; K01DK111785; F31DK122714; DOD W81XWH-07-2-0071.
3. Weight Regain Reverses Caloric Restriction-Induced Benefits on the Insulin-IGF-1 Nutrient-Sensing Pathway: Post Hoc Analysis From the CALERIE-2 Randomized Controlled Trial.
Post hoc analysis of the 2-year CALERIE-2 RCT showed that participants who regained >5% of baseline weight between months 12–24 lost earlier improvements in insulin AUC and IGF-1/IGFBP-1, whereas sustained weight loss preserved metabolic benefits and reduced biomarker-based biological age. Weight-loss maintenance, not aggressive initial restriction, drove durable hormonal/metabolic gains.
Impact: Clarifies that weight regain negates caloric restriction–induced improvements in nutrient-sensing pathways and biological aging, reframing obesity care toward maintenance strategies.
Clinical Implications: Clinical programs should prioritize weight-loss maintenance and relapse prevention to preserve insulin–IGF-1 pathway benefits and aging biomarkers; aggressive short-term restriction without maintenance support may be counterproductive.
Key Findings
- Participants who regained >5% baseline weight reversed improvements in insulin AUC and IGF-1/IGFBP-1 ratio achieved during initial caloric restriction.
- Sustained weight loss maintained metabolic benefits and was associated with greater reductions in biomarker-estimated biological age.
- The regain group had the largest initial caloric reductions, suggesting that steep early restriction may predispose to regain.
- Propensity score weighting balanced groups by baseline characteristics and supported robustness of trajectory comparisons.
Methodological Strengths
- Randomized controlled parent trial with 24-month follow-up and comprehensive biomarker profiling.
- Trajectory-based analysis with propensity score weighting to mitigate confounding.
Limitations
- Post hoc stratification by weight trajectory may introduce residual confounding and cannot establish causality.
- Small regain subgroup (n=20) limits precision and subgroup analyses.
Future Directions: Prospectively test maintenance-specific interventions (behavioral, pharmacologic) to sustain insulin–IGF-1 improvements and biological age reduction, and identify predictors of regain susceptibility.
OBJECTIVE: To investigate the long-term metabolic and hormonal consequences of sustained weight loss versus weight regain after 1 year of caloric restriction (CR), with attention to insulin resistance and type 2 diabetes risk. RESEARCH DESIGN AND METHODS: In the 2-year Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy 2 (CALERIE-2) trial (n = 220), participants were randomized to 25% CR or control diet. The intervention targeted weight loss over the first 6-12 months, followed by a 12-month maintenance phase. To assess weight-regain consequences, participants were stratified by weight trajectory regardless of randomization, and group differences were balanced by propensity score weighting. Cardiometabolic and hormonal markers of available participants (n = 190), as well as a biomarker-based estimate of biological age, were compared across weight trajectory groups. RESULTS: At 12 months, weight loss ranged from 5.0 to 5.8 kg between groups. Between months 12 and 24, most participants either maintained weight (n = 112) or continued to lose weight (n = 58), whereas a smaller group regained >5% of baseline weight (n = 20). This group had the largest initial caloric reductions. Weight regain reversed improvements in insulin area under the curve and the ratio of insulin-like growth factor 1 (IGF-1) to insulin-like growth factor-binding protein 1, and sustained weight loss maintained metabolic benefits and was associated with greater reductions in biological age. CONCLUSIONS: Substantial weight loss followed by weight regain can attenuate or reverse CR-induced benefits on key regulators of the insulin-IGF-1 nutrient-sensing pathway and markers of biological aging. Sustained, moderate weight loss more effectively improves insulin resistance and maintains favorable hormonal profiles linked to type 2 diabetes risk and aging biology.