AIMS:Similar to blood, saliva contains a broad range of biomarkers and may offer a non-invasive, repeatable specimen for endocrine and metabolic assessment. This review aims to synthesise and evaluate recent advances in the clinical translation of salivary biomarkers, while providing a critical assessment of the diagnostic reliability and clinical potential of key salivary biomarkers. MATERIALS AND METHODS:PubMed, Web of Science and ScienceDirect were searched for English-language articles published up to July 2025, with emphasis on studies from 2020 to 2025. We included articles with a focus on the clinical translation of salivary biomarkers for endocrine and metabolic disorders. The relevant studies on the physiology underlying the synthesis and transport of salivary biomarkers were also identified. RESULTS:Late-night salivary cortisol is the most clinically established marker and is guideline-endorsed for Cushing's syndrome, while salivary cortisone may improve the diagnostic accuracy. Salivary glycaemic biomarkers, such as glucose, 1,5-anhydroglucitol, fructosamine, glycated albumin and α-amylase, show potential for diabetes screening or monitoring. Salivary uric acid, inflammatory factors and adipokines may reflect hyperuricaemia, obesity and metabolic inflammation. However, most biomarkers remain exploratory and their clinical translation is limited by inconsistent collection procedures, oral disease, medication effects and analytical platforms. CONCLUSIONS:Salivary biomarkers offer a promising non-invasive approach for assessment of endocrine and metabolic disorders. Standardised procedures and large-scale multicentre validation are needed to define reliable clinical cutoffs and perform comparisons with blood-based reference standards. Applications for machine learning and wearable sensing technology can further promote clinical translation.

AIMS:The potential benefit of integrating continuous glucose monitoring (CGM) data with conventional glycaemic indicators in diabetes care remains to be determined. This study aimed to investigate the association between 1,5-anhydroglucitol (1,5-AG), a 1-2 weeks glycaemic marker with monitoring duration comparable to CGM, and diabetic retinopathy (DR). MATERIALS AND METHODS:The cross-sectional study included 5491 adults with type 2 diabetes. Participants were stratified by serum 1,5-AG levels (< 6.0 μg/mL, 6.0-10.0 μg/mL, and ≥ 10.0 μg/mL). Time in range (TIR) and glucose variability measures, including standard deviation (SD), coefficient of variation (CV), and mean amplitude of glycaemic excursions (MAGE), were calculated from CGM data. RESULTS:Overall, the median serum 1,5-AG level was 3.4 (1.7-7.1) μg/mL, with a DR prevalence of 25.3% (n = 1387). The prevalence of DR increased with descending 1,5-AG levels (p for trend < 0.001). Compared to patients with 1,5-AG levels ≥ 10.0 μg/mL (reference), the adjusted odds ratio (OR) for DR was 1.64 (95% CI 1.35-2.01) in individuals with 1,5-AG < 6.0 μg/mL. In subgroup analyses stratified by TIR tertiles (< 58%, 58%-80%, and ≥ 80%), low 1,5-AG levels remained significantly associated with an elevated risk of DR in both the highest (OR = 1.44, 95% CI 1.09-1.91) and middle TIR tertiles (OR = 1.64, 95% CI 1.13-2.42). Regarding CGM-derived glucose variability metrics, while CV and SD were associated with DR in the overall population, none of MAGE, CV, or SD was significantly associated with DR in the highest TIR tertile. CONCLUSIONS:Serum 1,5-AG is significantly associated with the prevalence of DR in type 2 diabetes. For patients with TIR ≥ 80%, 1,5-AG may reveal additional risk of DR.

AIMS:Glycated albumin (GA) has recently been recommended in the 2024 American Diabetes Association guidelines as an alternative glycemic marker, yet its complementary value alongside continuous glucose monitoring (CGM) metrics remains uncertain. METHODS:A total of 3251 individuals with type 2 diabetes were included. All participants underwent CGM, from which time in range (TIR) was calculated. Diabetic retinopathy (DR) was assessed by fundus examination, and diabetic kidney disease (DKD) was defined based on urinary albumin excretion and/or estimated glomerular filtration rate. Composite microvascular complications were defined as the presence of DR and/or DKD. RESULTS:Median GA and TIR were 20.5 % (16.8-25.9) and 75.0 % (60.0-87.0), respectively, and 45.8 % of participants had microvascular complications. After adjustment including TIR, the highest GA tertile wasindependently associated with higher odds of DR, DKD, and composite microvascular complications (odds ratios [ORs]: 1.31 [95 % CI 1.04-1.64], 1.58 [1.24-2.02], and 1.44 [1.17-1.79], respectively). These associations remained significant among participants achieving TIR > 70 % (ORs: 1.38 [1.04-1.83], 1.95 [1.43-2.65], and 1.57 [1.20-2.05], respectively). GA and TIR showed comparable C-statistics, while adding GA to TIR-based models improved net reclassification for microvascular complications by 13.2-16.3 %. CONCLUSIONS:In type 2 diabetes, GA is associated with microvascular complications independently of TIR and may provide complementary information when considered alongside TIR.

AIMS:Cardiovascular, kidney and metabolic diseases are pathophysiologically interrelated and are conceptualised within the cardiovascular-kidney-metabolic (CKM) syndrome framework. However, evidence linking continuous glucose monitoring (CGM) to CKM syndrome remains limited. This study examined the association between time in range (TIR), the core CGM metric, and advanced CKM syndrome. MATERIALS AND METHODS:A total of 2497 adults aged ≥ 60 years with type 2 diabetes were included. CKM syndrome was defined according to the American Heart Association Presidential Advisory, with stages 3-4 classified as advanced CKM syndrome. RESULTS:Participants with advanced CKM syndrome exhibited significantly lower TIR levels than those with non-advanced CKM syndrome (p < 0.001). After multivariable adjustment, each 1-standard deviation decrease in TIR was independently associated with higher odds of advanced CKM syndrome (OR 1.28, 95% CI 1.16-1.42). Restricted cubic spline analyses demonstrated a linear inverse association between TIR and advanced CKM syndrome, with the estimated OR approaching unity at approximately 70%. The prevalence of advanced CKM syndrome increased progressively across TIR categories of > 70%, 50%-70% and ≤ 50% (p for trend < 0.001). Although TIR levels of 50%-70% exceed the currently recommended target of > 50% for older adults, this range remained associated with higher odds of advanced CKM syndrome compared with TIR > 70% (OR 1.40, 95% CI 1.12-1.75). Higher TIR was not associated with increased hypoglycemia exposure. CONCLUSIONS:Lower TIR was associated with advanced CKM syndrome, supporting the potential value of CGM-derived TIR in evaluating multisystem cardiovascular-kidney-metabolic burden in older adults with type 2 diabetes.

Aims There is uncertainty whether traditional glycemic metrics remain associated with long-term outcomes among patients with type 2 diabetes who achieve recommended continuous glucose monitoring (CGM) targets. This study was aimed to investigate the association of glycated albumin (GA) and ratio of glucose management indicator to GA (GMI/GA) with risks of all-cause mortality in type 2 diabetes achieving CGM targets. Materials and Methods A total of 3482 patients with type 2 diabetes who met CGM targets, defined as time in range (TIR) >70%, time below range (TBR<3.9) <4%, and time above range (TAR(>10.0)) <25%, were included in the cohort study. Cox proportional hazards models and restricted cubic spline were used to evaluate associations of GA and GMI/GA with mortality. Results During a median follow-up of 11.0 years, 514 patients (14.8%) died. GA exhibited significant linear positive association with risks of all-cause mortality, and the highest GA quartile had 34% increased risk (HR = 1.34, 95% CI 1.01-1.78). Conversely, GMI/GA ratio showed significant non-linear association (p for nonlinearity = 0.042). Compared with the reference third quartile (0.36-0.40), participants in the lowest quartile (<0.30) had 40% higher risk of all-cause mortality (HR = 1.40, 95% CI 1.10-1.80). Conclusion Among patients achieving CGM targets, elevated GA and lower GMI/GA were associated with higher risks of all-cause mortality. These findings suggest that traditional glycemic metrics may complement CGM metrics in the assessment of long-term risks.

Cellular senescence contributes to obesity-associated adipose dysfunction, yet the upstream regulators of this process remain poorly understood. Here, we identified growth arrest and DNA damage-inducible protein 45 beta (Gadd45b) as an adaptive regulator of adipocyte senescence and systemic metabolic homeostasis. GADD45B expression was elevated in adipose tissue from obese human subjects and positively correlated with senescence-related markers. Adipocyte-specific Gadd45b deletion in mice caused depot-selective remodeling under high-fat diet, with inguinal fat hypertrophy but epididymal white adipose tissue (eWAT) atrophy, accompanied by enhanced DNA damage and pronounced senescence. These alterations thereby contributed to impaired lipolytic response, hepatic steatosis and insulin resistance, underscoring the vital role of Gadd45b in maintaining eWAT expandability during nutritional overload. Mechanistically, Gadd45b deficiency led to hypermethylation of fibroblast growth factor 1b (Fgf1b) promoter and reduced Fgf1 expression in eWAT, thereby exacerbating adipose senescence and metabolic abnormalities, while recombinant FGF1 treatment partially reversed these defects. Collectively, our findings establish Gadd45b as a depot-specific epigenetic regulator that sustains adipose tissue plasticity and links DNA damage responses to adipocyte senescence and metabolic homeostasis in obesity.

Introduction and Objective: GLYAT is a mitochondrial enzyme involved in medium-chain acyl-CoA metabolism, but its function in adipose tissue is unknown. We investigated the role of adipose GLYAT in obesity-associated metabolic dysfunction and its regulation of adipocyte mitochondrial function. Methods: Transcriptomic analysis was performed on paired subcutaneous and visceral adipose tissue samples from 236 participants (56 men, 180 women; age range 18-68 years). Using a BMI threshold of ≥25 kg/m² to classify overweight/obesity, the study population included 65 normal-weight and 171 overweight/obese individuals. Functional studies were performed in primary human and mouse adipocytes and in mice with AAV-mediated overexpression of GLYAT in inguinal white adipose tissue under cold exposure. Transcriptomic and targeted metabolomic analyses were used to explore underlying mechanisms. Results: Mitochondrial function-related genes were globally downregulated in adipose tissue from individuals with obesity. GLYAT expression correlated positively with BMI, WHR, body fat percentage, HOMA-IR, fatty liver index, adipose tissue insulin resistance index (Adipo-IR), and serum leptin level., and was inversely associated with adiponectin. GLYAT was enriched in mature adipocytes and increased during differentiation. Overexpression of GLYAT suppressed adipocyte energy metabolism, reduced mitochondrial respiratory complex proteins, and impaired cold-induced thermogenesis in vivo. Mechanistically, GLYAT overexpression inhibited fatty acid elongation, fatty acid metabolism, and oxidative phosphorylation and decreased the glycolytic intermediate 2-phospho-D-glycerate. Conclusion: GLYAT acts as a negative regulator of adipocyte mitochondrial function and glycolytic flux, contributing to impaired lipid metabolism and thermogenesis in obesity. Disclosure X. Li: None. T. Hu: None. X. Ma: None. Y. Bao: None. Funding National Natural Science Foundation of China (Grant NO.82400999)China Postdoctoral Science Foundation (2024M762052)

AIMS:Human adipose tissue is central to obesity-associated metabolic dysfunction. ANKRD53 is a human-specific, adipocyte-enriched ankyrin repeat scaffold protein with largely unknown function. We investigated its role in human adipocyte metabolism and the underlying mechanism. METHODS:RNA-seq analysis of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from 236 individuals quantified ANKRD53 expression and its association with metabolic traits. In human primary adipocytes, we assessed lipolysis (free fatty acid and glycerol release) and mitochondrial respiration (oxygen consumption rate) after ANKRD53 overexpression or knockdown. An AAV was used to overexpress ANKRD53 in mouse inguinal white adipose tissue (iWAT). Protein interactors were identified by immunoprecipitation-mass spectrometry, and knockdown experiments confirmed a functional role of ACSL1. RESULTS:ANKRD53 expression in both adipose depots was markedly reduced in obesity and inversely correlated with BMI, adiposity measures, insulin resistance indices, and circulating triglycerides, while positively associated with adiponectin and HDLc. In human adipocytes, ANKRD53 overexpression enhanced forskolin-stimulated lipolysis and mitochondrial respiration, whereas silencing impaired these processes. Adipose-targeted ANKRD53 overexpression in mice increased lipolysis in vivo. Mechanistically, ANKRD53 interacted with ACSL1 and promoted its mitochondrial localization, channeling lipolysis-derived FFAs into β-oxidation; silencing ACSL1 abrogated ANKRD53's effects. CONCLUSIONS:ANKRD53 is reduced in obesity and coordinates lipolysis with mitochondrial oxidative metabolism in human adipocytes, promoting efficient use of lipolysis-derived FFAs via ACSL1. These findings establish ANKRD53 as a key regulator of adipocyte energy metabolism and a potential therapeutic target for improving metabolic health in obesity.

Introduction and Objective: Although adipocyte hypertrophy is a histologic hallmark of adipose tissue dysfunction, its depot-specific contribution to systemic hyperglycemia and the underlying molecular mechanisms remain poorly defined. Methods: We analyzed paired subcutaneous and visceral adipose tissue samples from 516 adults undergoing bariatric surgery. Glucose tolerance status was classified by American Diabetes Association criteria 2025. Average adipocyte diameter was measured histologically and integrated with bulk RNA-Seq data from white adipose tissue and size-fractionated adipocytes to identify hypertrophy-driven transcriptional changes. Results: A total of 516 participants aged 32.4 (27.0-38.0) years with paired SAT and VAT samples were included, comprising 165 with normal glucose tolerance, 168 with impaired glucose tolerance, and 183 with type 2 diabetes. In multivariable Logistic regression models adjusting for overall adiposity and fat distribution, visceral adipocyte diameter was significantly associated with the risk of type 2 diabetes (OR 1.03, 95% CI 1.01-1.06), whereas subcutaneous adipocyte diameter showed no independent association (OR 1.02, 95% CI 0.99-1.04). With enlarged adipocyte size, substantial transcriptomic alterations of genes involved in glucose and lipid metabolism (e.g. fatty acid metabolism, fatty acid biosynthesis, insulin/glucagon signaling pathway, and insulin resistance) were observed. Moreover, visceral hypertrophy displayed a pro-inflammatory shift, characterized by altered abundances of dendritic cells, mast cells, mesothelium cells, and natural killer cells. Conclusion: Visceral adipocyte hypertrophy was significantly associated with hyperglycemia independent of overall adiposity and fat distribution. The current study provides a comprehensive overview of the adipocyte-hypertrophy associated transcriptomic landscape in both subcutaneous and visceral adipose tissue. Disclosure Y. Bao: None. T. Hu: None. X. Li: None. L. Yan: None. Y. Xu: None. X. Ma: None.

AIMS:This study aimed to establish a regression model for the relationship between time in range (TIR) and time in tight range (TITR) in individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) based on real-world continuous glucose monitoring (CGM) data. MATERIALS AND METHODS:A cross-sectional analysis was conducted on over 200 000 CGM users with diabetes. Participants self-reported basic demographic and clinical details via in-app fields. Exponential regression models were constructed to examine the TIR-TITR association for individuals with T1D and T2D, respectively. After controlling for coefficient of variation (CV), the model was extended to provide more precise glycemic targets for clinical use. Model performance was evaluated using the coefficient of determination (R2), root mean square error (RMSE), and Akaike information criterion (AIC). RESULTS:The TIR-TITR relationship exhibited a nonlinear relationship. Exponential models (TITRT1D = 8.54436 × exp[0.02414 × TIR]; TITRT2D = 5.52189 × exp[0.02839 × TIR]) provided the best fit compared to linear and quadratic models. A TIR of 70% corresponded to TITR values of 40.3%-46.3%, whereas achieving TITR of 50% required TIR of 73.2%-77.6%. For TIR below 60%, each 5% TIR increment boosted TITR by less than 5% points; above 60%, gains exceeded 5% points. Additionally, the inclusion of CV in the model was associated with reduced differences between the fitted T1D and T2D curves and improved the model's performance (TITR = 2.18448 × exp[0.03749 × TIR] +0.94018 × CV-14.99420). CONCLUSIONS:This study established the exponential model for TIR-TITR relationship in individuals with T1D and T2D, using a real-world CGM dataset. The model may provide new insights into the setting of individualized treatment goals.

The comparison between conventional glycemic markers and continuous glucose monitoring (CGM) in relation to adverse outcomes in the elderly with type 2 diabetes remains unclear. We aimed to assess associations of 1,5-anhydroglucitol (1,5-AG) and CGM metrics with carotid intima-media thickness (CIMT) as a surrogate of cardiovascular disease. The study included 2509 adults aged ≥ 60 years with type 2 diabetes. CIMT was measured by high-resolution ultrasonography, with abnormal CIMT defined as a mean thickness of ≥ 1.0 mm. Time in range (TIR), mean sensor glucose (MSG), time above range (TAR, > 10.0 mmol/L), standard deviation (SD), and coefficient of variation (CV) were calculated from CGM data. The median serum 1,5-AG was 3.9 (2.0, 8.0) μg/mL, and the prevalence of abnormal CIMT was 44.2

AIMS:Among the novel metrics derived from continuous glucose monitoring (CGM), time in tight range (TITR) has gained increasing attention. Our study aimed to investigate the relationship between 1,5-anhydroglucitol (1,5-AG) and TITR in patients with type 2 diabetes. MATERIALS AND METHODS:This cross-sectional study included 1531 moderately controlled patients with type 2 diabetes on a stable treatment regimen. TITR and time in range (TIR) were measured with CGM. Spearman correlation analysis was used to assess the relationship between serum 1,5-AG and TITR, and the predictive efficacy of serum 1,5-AG for identifying TITR > 50% was evaluated by the receiver operating characteristic curves. RESULTS:The median levels of serum 1,5-AG and glycated haemoglobin A1c (HbA1c) in the total population were 7.4 (4.4, 12.1) μg/mL and 7.0% (6.4%, 7.5%), respectively. The median TITR was 52.0% (32.0%, 69.0%). Spearman correlation analysis showed that serum 1,5-AG was positively correlated with TITR (p < 0.001). The optimal serum 1,5-AG cut-off for TITR >50% was 8.0 μg/mL, with an area under the curve (AUC) of 0.693 (0.667, 0.719). Serum 1,5-AG combined with fasting glucose or 2-hour postprandial glucose further improved the predictive power for identifying TITR > 50% (both p < 0.001). Across all subgroups, serum 1,5-AG showed acceptable predictive accuracy for TITR > 50% (AUCs around 0.700). CONCLUSIONS:Serum 1,5-AG was significantly correlated with TITR in patients with type 2 diabetes, with 8.0 μg/mL emerging as a potential cut-off for identifying TITR > 50%.

AIMS:Among the new glucose metrics derived from continuous glucose monitoring, the concept of time in tight range (TITR) has gained increasing attention. We aimed to assess the association between TITR and traditional glycemic indicators, such as glycated albumin (GA). METHODS:A total of 310 patients with type 2 diabetes on a stable glucose-lowering regimen over the previous 3 months were enrolled. TITR and time in range (TIR) were calculated using continuous glucose monitoring data collected over a minimum of 5 days. Spearman correlation analysis was performed to assess the relationships between traditional glycemic indicators, including GA and HbA1c, with TITR and TIR. Receiver operating characteristic curves were used to evaluate the predictive value of GA for TITR > 50% and TIR > 70%. RESULTS:The median levels of GA and HbA1c were 15.6% (14.0%, 17.3%) and 6.5% (6.1%, 7.1%), respectively. Median TITR and TIR were 70.0% (56.0%, 81.0%) and 91.0% (84.0%, 96.8%), respectively. Spearman correlation analysis showed a moderate negative relationship between GA and both TITR and TIR. The optimal GA cutoff for identifying either TITR > 50% or TIR > 70% was 17.4%. Moreover, combining GA with fasting plasma glucose or 2-h postprandial glucose significantly enhanced the ability to identify TITR > 50%, achieving performance comparable to the combination of HbA1c and plasma glucose. CONCLUSIONS:In patients with type 2 diabetes, a GA cutoff of 17.4% effectively identifies TITR > 50%.

Acute otitis media (AOM) is a leading cause of pediatric antibiotic prescriptions. Systemic antibiotics cause side effects and antibiotic resistance, whereas local delivery of antibiotics (directly to the middle ear) is hindered by an impermeable biological barrier, the tympanic membrane (TM). Here, we report on a liposome that hitchhikes on neutrophils to deliver antibiotics to the site of infection. Distinct from previous immune-cell-based therapies, we enable neutrophil hitchhiking via a topical application of hydroxylated liposomes, thus bypassing the invasive neutrophil harvesting procedures. The hydroxylated liposomes are opsonized by the complement protein fragments and subsequently internalized by native neutrophils. A simple topical application completely cures AOM in an established chinchilla model. It points to a low-cost and non-invasive treatment for this prevalent disease, poised to reduce pediatric antibiotic usage. ### Competing Interest Statement The authors have declared no competing interest.

Fructose-1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, is important for cancer progression. The post-translational regulation of FBP1 in hypoxic environments is still unclear. Here, we report that FBP1 is down-regulated, and a low expression level of FBP1 predicts a poor prognosis in pancreatic cancer. A hypoxic environment makes FBP1 more prone to degradation, and this effect can be reversed by inhibiting global O-GlcNAcylation signalling. O-linked N-acetylglucosamine transferase (OGT) interacts with FBP1 and induces its O-GlcNAcylation at serine 47 residue (FBP1-S47) to modulate its protein function in pancreatic cancer cells. O-GlcNAcylation of FBP1-S47 promotes FBP1 degradation and also influences the expression of canonical HIF-1α target genes involved in glucose metabolism, resulting in an increase in glucose uptake and lactate secretion in pancreatic cancer cells. In addition, O-GlcNAcylation of FBP1-S47 facilitates FBP1 K48-linked polyubiquitination at lysine 51 residue (FBP1-K51), in which GlcNAc moiety can serve as a prerequisite for an FBP1 ubiquitin ligase. FBP1 (K51) K48-linked polyubiquitination mediated protein degradation can also promote cancer progression, similarly to the O-GlcNAcylation of FBP1-S47. Our data uncover a mechanism whereby FBP1 can be regulated by a protein O-GlcNAcylation-polyubiquitination axis, paving the way to cancer cell metabolic reprogramming.

Metabolic enzymes, critical for cellular homeostasis, are frequently co-opted in a disease-specific manner to drive cancer progression. Here, we identify aldo-keto reductase family 1 member B10 (AKR1B10), down-regulated in gastrointestinal cancers, as a pivotal metastasis suppressor correlating with improved colorectal cancer (CRC) prognosis. Mechanistically, AKR1B10 activates protein phosphatase 2A (PP2A) by preventing redox-regulated nitration of its B56α subunit, preserving holoenzyme assembly and enabling c-Myc dephosphorylation at serine-62. Loss of AKR1B10 disrupts this pathway, stabilizing c-Myc, which drives integrin signaling and metastatic dissemination in CRC. We further demonstrate that lysine-125 of AKR1B10 is essential for its interaction with PP2A-Cα and B56α nitration, thereby attenuating CRC metastatic aggressiveness. Pharmacological restoration of PP2A activity effectively mitigates metastasis associated with AKR1B10 loss. In addition, c-Myc transcriptionally represses AKR1B10, establishing a feedback loop that sustains its down-regulation and enhances metastatic progression. This study uncovers an antimetastatic mechanism involving AKR1B10-mediated PP2A activation and highlights its potential as a biomarker and therapeutic target.

Acute otitis media (AOM) is a leading cause of oral antibiotic prescriptions for children in the U.S., often resulting in systemic side effects and contributing to antibiotic resistance. Local delivery of antibiotics across an intact tympanic membrane (TM) to treat the infection in the middle ear is challenging due to the impermeable TM, which blocks most molecules via the outermost stratum corneum layer. Recent research has identified liposomes encapsulating antibiotics as a highly promising approach to overcoming the intact TM during AOM, demonstrating superior delivery efficiency. However, their design principles remain elusive, especially regarding the desirable surface charge. While previous research has identified positive surface charge as being more effective for crossing healthy stratum corneum, this study illustrates the opposite is true during infection. We compared hydrogel formulations containing positively and negatively charged liposomes in terms of their in vitro release, permeation across intact TM ex vivo, in vivo AOM treatment efficacy, and tissue-level biocompatibility using an established chinchilla model. Our results indicate that negatively charged liposomes outperformed positively charged ones, successfully eradicating 100% of AOM cases. We attributed this to interactions between the negatively charged liposomes and the immune response to infection. Specifically, the complement activation, which triggers neutrophils' phagocytosis, is enhanced in response to the negatively charged liposomes. Our findings highlight an opportunity to improve delivery efficiency by considering the pathophysiology more wholistically during the design of drug delivery vehicles.

Purine metabolism enzymes have a well-established role in maintaining the nucleotide pool, thereby sustaining cellular energy homeostasis. Although reduced purine nucleotide concentrations have been reported can influence uncoupling protein 1 (UCP1)activity in thermogenic adipocytes, our study identifies adenylosuccinate synthase 1 (Adss1), an enzyme in de novo purine biosynthesis, as a critical regulator of metabolic remodeling in inguinal white adipose tissue (iWAT) through a mechanism distinct from UCP1 activity. Adipose-specific Adss1 knockout mice showed increased energy expenditure and resistance to diet-induced obesity with improved metabolic dysfunction. Loss of Adss1 upregulates glycerol kinase (Gk) expression, thereby stimulating glycerol-dependent fatty acid re-esterification in iWAT. This adaptation prevents lipotoxic accumulation of free fatty acids and drives lipid synthesis-oxidation cycling, activating thermogenic programs. The Adss1 deficiency-driven iWAT browning and re-esterification are abolished in adipose-specific Adss1 and Gk double-knockout mice, confirming the functional dependence on Gk. Mechanistically, Adss1 interacts with histone deacetylase 3 (HDAC3) in the cytosol of beige adipocytes, altering its nucleo-cytoplasmic distribution. Adss1 deficiency reduced nuclear HDAC3 and increased cytosolic pools, which suppresses HDAC activity and enhances histone H3 lysine 27 acetylation at the Gk promoter, elevating Gk expression. Collectively, our findings reveal an unrecognized role of Adss1 in adipose physiology, highlighting its potential as a regulator of adipose energy metabolism.