Daily Endocrinology Research Analysis
Three papers advance endocrine science across metabolism and hypertension: (1) Decr1 drives excessive cardiac fatty acid oxidation in diabetic cardiomyopathy via a PDK4–HDAC3–HADHA axis; targeting Decr1 or using natural inhibitors improved cardiac function in mice. (2) MTCH2 suppresses adipose thermogenesis by inhibiting autophagy; its depletion protects against diet‑induced obesity across species. (3) A crossover clinical trial shows the Cav1.3 ligand cinnarizine does not lower aldosterone acti
Summary
Three papers advance endocrine science across metabolism and hypertension: (1) Decr1 drives excessive cardiac fatty acid oxidation in diabetic cardiomyopathy via a PDK4–HDAC3–HADHA axis; targeting Decr1 or using natural inhibitors improved cardiac function in mice. (2) MTCH2 suppresses adipose thermogenesis by inhibiting autophagy; its depletion protects against diet‑induced obesity across species. (3) A crossover clinical trial shows the Cav1.3 ligand cinnarizine does not lower aldosterone activity in primary aldosteronism, underperforming nifedipine.
Research Themes
- Adipose thermogenesis and autophagy regulation
- Metabolic remodeling in diabetic cardiomyopathy
- Pharmacologic targeting in primary aldosteronism
Selected Articles
1. Therapeutic Targeting of Decr1 Ameliorates Cardiomyopathy by Suppressing Mitochondrial Fatty Acid Oxidation in Diabetic Mice.
Decr1 expression was consistently upregulated in diabetic cardiomyopathy. Cardiomyocyte-specific Decr1 knockdown preserved ejection fraction and fractional shortening and reduced hypertrophy, fibrosis, apoptosis, and oxidative damage, whereas overexpression aggravated disease. Mechanistically, Decr1 increased PDK4, leading to HDAC3 mitochondrial translocation and HADHA deacetylation, driving excessive FAO. Two natural products (Atranorin, Kurarinone) inhibited Decr1 and improved cardiac function in diabetic mice.
Impact: Identifies Decr1 as a central regulator of maladaptive cardiac FAO with a defined PDK4–HDAC3–HADHA mechanism and presents drug-like natural inhibitors that ameliorate DCM phenotypes in vivo.
Clinical Implications: While preclinical, targeting Decr1 or downstream PDK4/HDAC3 signaling could complement glucose-centric strategies in diabetic cardiomyopathy by curbing lipotoxic FAO. These findings motivate translational work toward first-in-human studies of Decr1 inhibitors.
Key Findings
- Decr1 is upregulated in diabetic hearts and cardiomyocytes (+255% and +281%, p<0.0001).
- Cardiomyocyte-specific Decr1 knockdown improved EF (+41%) and FS (+24%) and reduced hypertrophy (−34%), fibrosis (−69%), apoptosis (−56%), and oxidative damage (−59%).
- Mechanism: Decr1 upregulates PDK4, inducing HDAC3 phosphorylation/mitochondrial translocation and HADHA deacetylation, driving excessive FAO.
- Overexpression of PDK4 abrogated the benefits of Decr1 downregulation in DCM mice.
- Natural products Atranorin and Kurarinone inhibited Decr1 and improved EF/FS in DCM.
Methodological Strengths
- Integrated gain/loss-of-function in vivo and in vitro with RNA sequencing and functional readouts (EF/FS, pathology).
- Target validation with pharmacologic inhibitors that improved cardiac function in a disease model.
Limitations
- Preclinical mouse and cell models; no human validation or long-term safety data.
- Natural inhibitors identified require optimization, PK/PD profiling, and off-target assessment.
Future Directions: Validate Decr1/PDK4/HDAC3/HADHA axis in human myocardial tissues, optimize small-molecule inhibitors, and test efficacy and safety in large-animal DCM models prior to early-phase clinical trials.
BACKGROUND: A significant increase in mitochondrial fatty acid oxidation (FAO) is now increasingly recognized as one of the metabolic alterations in diabetic cardiomyopathy (DCM). However, the molecular mechanisms underlying mitochondrial FAO impairment in DCM remain to be fully elucidated. METHODS: A type 2 diabetes (T2D) mouse model was established by a combination of high-fat diet (HFD) and streptozotocin (STZ) injection. Neonatal rat cardiomyocytes were treated with high glucose (HG) and palmitic acid (HP) to simulate diabetic cardiac injury. Gain- and loss-of-function approaches and RNA sequencing were utilized to i
2. MTCH2 Suppresses Thermogenesis by Regulating Autophagy in Adipose Tissue.
Across species, MTCH2 acts as a brake on thermogenesis. Adipose-specific MTCH2 depletion increases UCP1, mitochondrial biogenesis, lipolysis, and browning of scWAT, boosting energy expenditure and protecting mice from HFD-induced obesity and metabolic dysfunction. Integrated RNA-seq and proteomics indicate MTCH2 suppresses thermogenesis by negatively regulating autophagy via a Bcl‑2–dependent mechanism.
Impact: Reveals a conserved, targetable brake on thermogenesis linking autophagy to adipose energy expenditure, opening routes for anti-obesity therapeutics beyond appetite or absorption modulation.
Clinical Implications: Therapeutic inhibition of MTCH2 or modulation of its Bcl-2–autophagy axis could enhance brown/beige fat thermogenesis to treat obesity and metabolic disease, pending human mechanistic validation and safety studies.
Key Findings
- MTCH2 identified as a conserved negative regulator of energy homeostasis in flies, rodents, and humans.
- Adipose-specific MTCH2 knockout protects mice from HFD-induced obesity and metabolic disorders by increasing energy expenditure.
- Upregulation of UCP1, mitochondrial biogenesis, and lipolysis in BAT and scWAT with enhanced browning of scWAT.
- Integrated RNA-seq/proteomics reveal MTCH2 suppresses thermogenesis by negatively regulating autophagy via a Bcl-2–dependent mechanism.
Methodological Strengths
- Cross-species validation (flies, mice, humans) with adipose-specific genetic models.
- Integrated transcriptomic and proteomic analyses linking phenotype to mechanism.
Limitations
- Lack of interventional human studies; causal roles inferred without pharmacologic MTCH2 modulation in humans.
- Long-term safety of enhancing autophagy/thermogenesis remains unknown.
Future Directions: Develop selective MTCH2 modulators, map downstream autophagy nodes amenable to drugging, and test efficacy/safety in human adipocyte systems and early-phase trials.
Stimulating adipose tissue thermogenesis has emerged as a promising strategy for combating obesity, with uncoupling protein 1 (UCP1) playing a central role in this process. However, the mechanisms that suppress adipose thermogenesis and energy dissipation in obesity are not fully understood. This study identifies mitochondrial carrier homolog 2 (MTCH2), an obesity susceptibility gene, as a negative regulator of energy homeostasis across flies, rodents, and humans. Notably, adipose-specific MTCH2 depletion in mice protects against high-fat-diet (HFD)-induced obesity and metabolic disorders. Mecha
3. Evaluation of Aldosterone Suppression by Cinnarizine, a Putative Cav1.3 Inhibitor.
In vitro, cinnarizine and nifedipine both reduced aldosterone and CYP11B2 expression, but at comparable or higher concentrations for cinnarizine. In a registered, open-label crossover trial in 15 PA adults, nifedipine reduced the aldosterone-to-renin ratio (ARR), whereas cinnarizine did not; plasma aldosterone rose with both and urinary tetrahydroaldosterone remained unchanged. Clinically, cinnarizine underperformed nifedipine for suppressing aldosterone activity.
Impact: Refutes a plausible Cav1.3-targeting repurposing strategy in PA at clinical doses, sharpening drug development toward more potent/selective Cav1.3 blockers or alternative calcium-independent pathways.
Clinical Implications: Cinnarizine should not be expected to suppress aldosterone activity in PA at standard doses; nifedipine remains preferable when using calcium channel blockade. Patient management should not substitute established therapies with cinnarizine for PA.
Key Findings
- Both cinnarizine (up to 30 μM) and nifedipine (up to 100 μM) reduced aldosterone and CYP11B2 expression in HAC15 cells.
- In a 15-patient crossover trial, nifedipine reduced ARR (F=3.25; P=.047) while cinnarizine did not.
- Plasma aldosterone rose with both drugs (F=4.77; P=.013); urinary tetrahydroaldosterone was unchanged.
- At clinical doses, cinnarizine was inferior to nifedipine for suppressing aldosterone activity in PA.
Methodological Strengths
- Translational design combining mechanistic in vitro assays with a registered human crossover study.
- Use of hierarchical outcomes (ARR, urinary THA, PAC) and within-subject comparison.
Limitations
- Small, open-label sample (n=15) with short 2-week treatment periods per arm; potential carryover despite washout.
- Cinnarizine exposure may not have achieved sufficient Cav1.3 blockade in vivo; no dose–response exploration.
Future Directions: Develop/select more potent and selective Cav1.3 inhibitors; evaluate alternative calcium channel–independent mechanisms in aldosterone regulation; conduct randomized, blinded trials with adequate dosing and duration.
CONTEXT: Primary aldosteronism (PA) is commonly caused by somatic mutations of CACNA1D encoding Cav1.3, one of the four L-type calcium channels. The over-the-counter drug, cinnarizine, fits the Cav1.3 crystal structure pore domain. OBJECTIVE: We hypothesized that Cav1.3 blockade by cinnarizine may achieve similar, or greater, reduction in aldosterone secretion than nonselective Cav1.2/1.3 blockade by nifedipine. METHODS: Separate wells of angiotensin II-stimulated HAC15 cells were treated with either cinnarizine (1-30 μM) or nifedipine (1-100 μM). Aldosterone concentrations were measured in culture medi