Daily Endocrinology Research Analysis
Analyzed 103 papers and selected 3 impactful papers.
Summary
Analyzed 103 papers and selected 3 impactful articles.
Selected Articles
1. Gut microbiota responses to bariatric surgery are associated with metabolic outcomes and type 2 diabetes remission.
In an RCT-derived subanalysis (n=77), both RYGB and SG shifted the gut microbiome, with larger changes after RYGB. SG-associated microbiome features correlated with higher GLP-1, improved beta-cell function, and 5-year T2D remission, alongside increased gene richness and fermentative/butyrate pathways, independent of weight loss.
Impact: Identifies microbiome signatures linked to durable diabetes remission after bariatric surgery, providing mechanistic insight beyond weight loss and suggesting biomarker-guided care.
Clinical Implications: Microbiome-based biomarkers may refine surgical selection, predict remission, and inform microbiota-targeted adjuvant strategies to enhance metabolic outcomes.
Key Findings
- Both RYGB and SG induced microbiome shifts in the same direction, with larger magnitude after RYGB.
- SG-associated microbiome composition correlated with circulating GLP-1, beta-cell function, and 5-year T2D remission.
- Remission-linked microbiomes showed increased gene richness and metabolic potential for fermentation, methanogenesis, and butyrate production independent of weight loss.
Methodological Strengths
- Prospective sampling pre- and 12 months post-surgery in an RCT framework
- Integration of microbiome profiles with hormonal, beta-cell, and long-term clinical outcomes
Limitations
- Subanalysis with modest sample size limits causal inference
- Stool microbiome may not fully capture mucosal or small intestinal communities
Future Directions: Prospective validation of microbiome biomarkers for remission prediction, interventional trials targeting identified microbial pathways, and multi-omics integration with host metabolomics and proteomics.
Bariatric surgeries, such as Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), improve obesity and type 2 diabetes (T2D). Both surgeries affect the gut microbiota, but their contribution to T2D remission remains unclear. In this subanalysis (RYGB, n = 39; SG, n = 38) of the randomized controlled Oseberg trial ( NCT01778738 ), in which participants underwent either RYGB or SG surgery, we profiled the faecal microbiome of individuals with obesity and T2D before and 12 months after surgery. We show that both surgerie
2. A nutrient-responsive AMPK/TBK1 circuit restricts adipocyte catabolism.
TBK1 acts as a nutrient/inflammation-induced brake on AMPK in adipocytes via a PGC1α–NRF1–TBK1 axis. Genetic deletion or pharmacologic inhibition of TBK1 enhances fasting AMPK activation, mitochondrial function, lipolysis, and—when combined with AICAR—drives greater weight loss and metabolic improvement while suppressing adipose inflammation and liver fibrosis.
Impact: Defines a druggable feedback loop limiting adipocyte catabolism and demonstrates combination therapy (TBK1 inhibition plus AMPK activation) that synergistically enhances metabolic health.
Clinical Implications: Supports clinical exploration of TBK1 inhibitors (e.g., amlexanox) combined with AMPK activators to counter metabolic adaptation, augment weight-loss durability, and reduce adipose inflammation and liver fibrosis.
Key Findings
- Fasting or AMPK activation induces Tbk1 via PGC1α/NRF1, which then phosphorylates to limit AMPK activity—a nutrient-sensitive AMPK/TBK1 feedback loop.
- Adipocyte-specific TBK1 deletion or pharmacologic TBK1 inhibition enhances AMPK activation, mitochondrial function, and lipolytic gene expression.
- Amlexanox plus AICAR combination therapy augments weight loss, improves glucose tolerance/insulin sensitivity, and suppresses adipose inflammation and hepatic fibrotic programs.
Methodological Strengths
- Convergent evidence from genetics (adipocyte-specific knockout) and pharmacology (TBK1 inhibitor, AMPK activator) in lean and obese mice
- Comprehensive phenotyping across mitochondrial function, lipolysis, inflammation, and liver fibrosis
Limitations
- Preclinical mouse and cellular models; human translational data are indirect
- Potential off-target or pathway complexity with TBK1 inhibitors and AMPK activators
Future Directions: Early-phase clinical trials testing TBK1 inhibition with/without AMPK activation in obesity; biomarker strategies to monitor AMPK/TBK1 axis activity and metabolic adaptation.
Metabolic adaptation to both caloric excess and restriction promotes energy conservation by suppressing catabolic pathways via feedback mechanisms that remain incompletely defined. We identified TANK binding kinase 1 (TBK1) as a nutrient- and inflammation-responsive brake on AMPK signaling in adipocytes. Fasting or pharmacological AMPK activation induced Tbk1 transcription via a PGC1α/nuclear respiratory factor 1 axis, which, in turn, limited AMPK activity through a phosphorylation cascade to conserve energy. In obesity, this AMPK/TBK1 axis was disrupted due to chronically elevated basal TBK1, thereby restricting energy expenditure during fasting. Adipocyte-specific TBK1 deletion enhanced fasting-induced AMPK activation, mitochondrial function, and lipolytic gene expression in both lean and obese mice. Pharmacological TBK1 inhibition with amlexanox recapitulated these effects. Combined treatment of mice with amlexanox and the AMPK activator AICAR enhanced weight loss, improved glucose tolerance and insulin sensitivity, and suppressed inflammatory and lipogenic programs in adipose tissue, as well as fibrotic gene expression in the liver. Building on prior clinical observations linking TBK1 inhibition to metabolic health, these findings defined a nutrient-sensitive AMPK/TBK1 feedback loop that limited adipocyte catabolism and suggested that dual targeting of TBK1 and AMPK may help counteract metabolic adaptation and enhance the durability of obesity therapies.
3. Drp1 regulates mitochondrial health and controls skeletal muscle mass through the Erk1/2-Nur77 pathway.
Acute skeletal muscle Drp1 deletion triggers Parkin-mediated mitophagy, mtDNA loss, and severe atrophy; dual Drp1/Parkin loss restores mtDNA but not muscle mass. Drp1 deficiency suppresses Erk1/2 signaling and Nur77, while β2-adrenergic activation (clenbuterol) reactivates Erk1/2, restores Nur77, and rescues atrophy—defining a Drp1–Erk1/2–Nur77 axis.
Impact: Links mitochondrial fission machinery to a defined nuclear signaling cascade controlling muscle mass and demonstrates pharmacologic rescue, nominating new targets for sarcopenia and mitochondrial myopathies.
Clinical Implications: Suggests therapeutic avenues targeting β2-adrenergic signaling, Erk1/2–Nur77, or mitochondrial dynamics to mitigate muscle atrophy in metabolic and mitochondrial diseases; cautions regarding β2-agonist safety profile.
Key Findings
- Acute muscle-specific Drp1 deletion increased Parkin-mediated mitophagy, reduced mtDNA, and caused severe atrophy.
- Dual Drp1/Parkin deletion restored mtDNA but did not prevent muscle loss, indicating additional signaling requirements for mass maintenance.
- Drp1 loss suppressed Erk1/2 and Nur77; clenbuterol reactivated Erk1/2, restored Nur77, and rescued atrophy, defining a Drp1–Erk1/2–Nur77 axis.
Methodological Strengths
- Genetic perturbations (acute Drp1 deletion; dual Drp1/Parkin deletion) with pharmacologic rescue (β2-agonist)
- Multi-level mechanistic readouts (mitophagy, mtDNA, respiratory chain, Erk1/2–Nur77 signaling, phenotype)
Limitations
- Preclinical mouse data without human validation limits immediate translational applicability
- β2-adrenergic agonists have known safety/tolerability concerns for chronic use
Future Directions: Test modulation of Erk1/2–Nur77 in human myotubes and patient tissues; develop safer modulators of the axis or mitochondrial dynamics; evaluate efficacy in models of sarcopenia and cachexia.
The maintenance of skeletal muscle mass relies on mitochondrial quality control, including balanced dynamics and mitophagy. Dynamin-related protein 1 (Drp1), a central mediator of mitochondrial fission, is essential for these processes, yet its role in muscle mass regulation remains incompletely defined. Here, we show that acute Drp1 deletion in the skeletal muscle increases Parkin-mediated mitochondrial degradation, reduces mitochondrial DNA (mtDNA) content, and leads to severe muscle atrophy. Although dual deletion of Drp1 and Parkin restores mtDNA content, muscle loss persists. Mechanistically, Drp1 loss impairs mitochondrial respiratory chain activity, suppressing extracellular signal-regulated kinase 1/2 (Erk1/2) signaling and down-regulating the nuclear receptor subfamily 4 group A member 1 (Nur77). Pharmacologic β2-adrenergic receptor activation with clenbuterol reactivated Erk1/2, restored Nur77 expression, and rescued muscle atrophy. These findings define a Drp1-Erk1/2-Nur77 signaling axis linking mitochondrial integrity to skeletal muscle mass and identify a potential therapeutic target for muscle degeneration in mitochondrial and metabolic diseases.