ABSTRACT Netanasvir Phosphate is a novel second-generation NS5A inhibitor used for the treatment of chronic hepatitis C virus (HCV) infection. This study investigated the absorption, distribution, metabolism, and excretion (ADME), and the metabolite profile of [¹⁴C]Netanasvir Phosphate. In a single-dose, open-label study, six healthy Chinese male volunteers received an oral dose of 100 mg/200 µCi of [¹⁴C]Netanasvir Phosphate under fed conditions. Blood, urine, and fecal samples were collected for up to 336 h post-dose. Total radioactivity was measured using oxidative combustion and liquid scintillation counting, and the parent drug and its metabolites were analyzed by validated liquid chromatography–tandem mass spectrometry and low-energy radiometric detection and mass spectrometry methods. The pharmacokinetic profile showed a median T max of 5.5 h and a mean terminal half-life of 30.6 ± 8.52 h. The average total recovery of radioactivity was 97.73% ± 1.90%, with feces accounting for 97.71% of the administered dose and urine only 0.02%, indicating that fecal excretion is the primary elimination pathway. The parent drug was the predominant circulating and excreted component, representing 93.89% of plasma radioactivity and 78.78% of the administered dose in feces. Only minor metabolites were detected, including demethylated and oxidized derivatives. The drug was well tolerated, with no serious adverse events (SAEs) or dose-limiting toxicities observed. This mass balance and metabolite profiling study provides essential evidence supporting the favorable pharmacokinetic characteristics and metabolic stability of [¹⁴C]Netanasvir Phosphate and offers a scientific foundation for further clinical development in HCV-infected populations.

Introduction:This clinical trial aimed to assess the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of LW402, a preferential JAK1 inhibitor, in healthy participants, so as to provide support for its further development in treating autoimmune diseases. Methods:The study included two phases: a single ascending dose (10-400 mg) with 54 participants and a multiple ascending dose (50-150 mg, b.i.d for 6 days plus a single dose on day 7) with 36 participants. Safety, PK (from timed blood samples), and PD (JAK1/JAK2 signaling) were evaluated. Results:No serious adverse events were reported; only mild treatment-emergent adverse events (TEAEs), such as sinus bradycardia and gastrointestinal issues, occurred. LW402 was rapidly absorbed (median tmax: 0.42-1.0 hours), with slightly super-proportional exposure and minimal accumulation, and preferentially inhibited JAK1-mediated signaling. Discussion:LW402's favorable safety profile, predictable PK characteristics, and selective JAK1 inhibition collectively support its continued development for the treatment of autoimmune diseases. Clinical Trial Registration:http://www.chinadrugtrials.org.cn, identifier CTR20201897.

Background and Objective:Cap-dependent endonuclease (CEN) inhibitors are a promising novel class of antiviral agents for influenza treatment. This phase I study aimed to evaluate the mass balance, excretion pathways, and pharmacokinetics of pixavir marboxil (TG-1000), a novel CEN inhibitor prodrug, in healthy humans. Methods:Six healthy Chinese male participants received a single oral dose of 40 mg (100 μCi) [14C]pixavir marboxil. Blood, urine, and fecal samples were collected at predefined intervals up to 384 h post-dose. Total radioactivity was determined using oxidative combustion and liquid scintillation counting. Pharmacokinetic parameters were calculated using non-compartmental analysis, and metabolite profiling was conducted using high-performance liquid chromatography coupled with radiochemical detection and high-resolution mass spectrometry. Results:Intact pixavir marboxil was undetectable in plasma. Systemic exposure primarily consisted of its active metabolite, pixavir (TG-0527), and a subsequent glucuronide conjugate, TG-0600771. The geometric mean areas under the curve ( A U C 0 - ∞ ) for total radioactivity, pixavir, and TG-0600771 in six participants were 4,220 hng Eq./mL, 2,490 hng/mL, and 981 hng/mL, respectively. The administered radioactive dose demonstrated a mean cumulative recovery of 91.29%, with 85.62% recovered in feces and 5.68% in urine. Metabolite profiling identified pixavir and TG-0600771 as the major metabolites, with no major cytochrome P450 (CYP)-mediated oxidative metabolites observed in plasma. The single dose of [14C]pixavir marboxil was safe and well-tolerated. Conclusion:Pixavir marboxil exhibits a favorable pharmacokinetic profile characterized by rapid systemic conversion to its active metabolite, CYP-independent metabolism, and predominantly non-renal clearance. These favorable pharmacokinetic characteristics support a well-characterized disposition profile with limited reliance on CYP-mediated metabolism and renal excretion of active pixavir. Trial Registration:This study was registered with Drug Clinical Trial Registration and Information Disclosure Platform, National Medical Products Administration (NMPA), number CTR20231822 (http://www.chinadrugtrials.org.cn/).

Suraxavir marboxil (GP681) is a prodrug of a novel polymerase acidic protein inhibitor, and its metabolite GP1707D07 prevents the replication of influenza virus by selectively inhibiting the cap-dependent nucleic acid endonuclease of influenza virus. This study evaluates the safety, tolerability, and pharmacokinetics of suraxavir marboxil after a single dose and assesses the effect of a high-fat, high-calorie meal on the pharmacokinetics of suraxavir marboxil in healthy Chinese subjects. The study included two parts: single ascending-dose study (SAD) and food effect study (FE). In SAD, subjects were randomized to single-dose suraxavir marboxil (20, 40, 60, or 80 mg) or placebo. In FE, subjects (n = 16) were randomized to single-dose suraxavir marboxil 40 mg in fasting and fed states. Safety assessment and sample collection were in accordance with the protocol. Suraxavir marboxil was well tolerated in healthy Chinese subjects in both SAD and FE, and all adverse events recovered without treatment after discontinuation of suraxavir marboxil. In SAD, after administration of suraxavir marboxil in the dosage range of 20-80 mg, the time to maintain the clinically defined effective target blood concentration is about 72-136 h. In FE, a high-fat, high-calorie meal reduced Cmax by approximately 19% and AUC0-∞ by approximately 15%. Suraxavir marboxil was well tolerated in healthy Chinese subjects. Based on the safety and pharmacokinetic data, 20-80 mg single oral dosing was supported for further clinical development. Food intake may slightly reduce the rate and extent of absorption of suraxavir marboxil.The study was registered on https://classic.clinicaltrials.gov/ (registration no.: NCT04729764).

Chronic superficial gastritis (CSG) severely affects quality of life and can progress to worse gastric pathologies. Traditional Chinese Medicine (TCM) effectively treats CSG, as exemplified by Jinhong Tablets (JHT) with known anti-inflammatory properties, though their mechanism remains unclear. This study integrated network pharmacology, untargeted metabolomics, and gut microbiota analyses to investigate how JHT alleviates CSG. A rat CSG model was established and evaluated via H E staining. We identified JHT's target profiles and constructed a multi-layer biomolecular network. Differential metabolites in plasma were determined by untargeted metabolomics, and gut microbiota diversity/composition in fecal and cecal samples was assessed via 16S rRNA sequencing. JHT markedly reduced gastric inflammation. Network pharmacology highlighted metabolic pathways, particularly lipid and nitric oxide metabolism, as essential to JHT's therapeutic effect. Metabolomics identified key differential metabolites including betaine (enhancing gut microbiota), phospholipids, and citrulline (indicating severity of CSG). Pathway enrichment supported the gut microbiota's involvement. Further microbiota analysis showed that JHT increased betaine abundance, improved short-chain fatty acid production, and elevated Faecalibaculum and Bifidobacterium, thereby alleviating gastric inflammation. In conclusion, JHT alleviates CSG via diverse metabolic processes, especially lipid and energy metabolism, and influences metabolites like betaine alongside gut microbes such as Faecalibaculum and Bifidobacterium. These findings underscore JHT's therapeutic potential and deepen our understanding of TCM's role in CSG management.

ABSTRACT SC1011 (sufenidone) is a novel pyridone derivative with therapeutic potential for idiopathic pulmonary fibrosis (IPF). Two Phase 1 studies evaluated the safety and pharmacokinetics of single (SAD) and multiple ascending doses (MAD) of SC1011 immediate‐release (IR) and modified‐release (MR) oral formulations in healthy adult subjects. In Phase 1a, subjects were randomized to receive oral SC1011 IR or placebo in SAD (50 mg‐300 mg) or MAD (100 mg and 200 mg) twice daily for 7 days. The Phase 1b study consisted of three treatment groups that received 100, 150, or 200 mg SC1011 MR twice daily for 7 days. SC1011 IR was absorbed rapidly (mean time to maximum concentration, Tmax ≤ 1 h) and eliminated rapidly (mean terminal half‐life, t1/2: 1.23–2.64 h) following 50–300 mg single‐dose administrations. Reduced maximum plasma concentration (Cmax), delayed Tmax, and comparable total exposure were observed with the MR formulation compared with the IR formulation. Both formulations demonstrated dose‐proportional pharmacokinetics at the applied dose ranges, and no obvious accumulation of systemic exposure was observed upon repeated administration. All treatment‐emergent adverse events (TEAEs) with both formulations were mild or moderate in severity, and gastrointestinal reactions were the most frequently reported TEAEs. The tolerability of SC1011 was markedly improved with the MR formulation. Exposure–adverse event (AE) analysis with the most frequent AEs identified Cmax rather than total exposure as a good predictor of AEs. Compared to the IR formulation, SC1011 MR demonstrated improved exposure and tolerability, supporting its further development in patients with IPF.

Objective:This Phase I study evaluated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of BGT-002, a novel ATP-citrate lyase (ACLY) inhibitor, in healthy Chinese adults. Methods:This study included three parts: Part I (single-ascending-dose study), Part II (multiple-ascending-dose study), and Part III (food effect study). A total of 104 healthy subjects were enrolled in the study and were given BGT-002 tablet or placebo per protocol requirements. Blood samples were collected for pharmacokinetic and pharmacodynamic analysis. Safety was assessed by clinical examinations and adverse events. Results:In Part I, BGT-002 demonstrated rapid absorption with a Tmax of 0.67 to 1.75 hours, and slow elimination with a T1/2 of 24.53 to 72.86 hours, prolonged with increased dosages. Cmax and AUC0-∞ ranged from 1.55 to 48.39 μg/mL, and 31.09 to 2930.69 h·μg/mL, respectively. In Part II, the accumulation index (Rac) of Cmax and AUCtau following 14 days of consecutive administration were 3.53 to 3.62 and 5.29 to 5.59, respectively, with a dose-proportionality PK profile. The levels of total cholesterol (TC), non-high-density lipoprotein cholesterol (non-HDL-C), and low-density lipoprotein cholesterol (LDL-C) were maximally decreased by 15.80%, 18.50%, and 22.37%, respectively. In Part III, the geometric mean ratio (90% CI) of fed to fasting condition in Cmax and AUC0-∞ of BGT-002 were 73.11% and 98.36%, respectively, indicating a minor food effect on the absorption rate. Across the study, two cases of Grade 3 adverse events (elevated blood triglycerides) were reported, both of which were assessed as not related to BGT-002. No serious adverse events were observed. Conclusion:BGT-002 demonstrated favorable safety, tolerability, and lipid-lowering effects, supporting its potential for further clinical development. Clinical Trial Registration:ChiCTR2200057793(https://www.chictr.org.cn/showproj.html?proj=160210); ChiCTR2300067474(https://www.chictr.org.cn/showproj.html?proj=182183); ChiCTR2300067472(https://www.chictr.org.cn/showproj.html?proj=184079).

AbstractThis study evaluated the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and food effects (FE) of SC0062, a highly active endothelin‐A (ETA) receptor antagonist, in healthy subjects. The primary objectives of this first‐in‐human phase I study, comprised of single‐ascending‐dose, multiple‐ascending‐dose, and FE parts, were to characterize the safety and tolerability of SC0062, and FE. The secondary objectives were to determine the PK behavior of SC0062 and its major active metabolite M18, whereas exploratory objectives focused on PD effects, principally effects on endothelin‐1 (ET‐1) and total bile acids (TBA). Single doses of 10 to 100 mg and multiple daily doses of 20 and 50 mg for 6 days were well tolerated. SC0062 was rapidly absorbed and plasma exposure of SC0062 and M18 increased disproportionately with dose, achieving steady state by day 3, with accumulation ratios of 1.22 and 1.89 on day 6 for SC0062 and M18, respectively. The geometric mean (geometric standard deviation) terminal elimination half‐life (t1/2) values of SC0062 and M18 were 7.25 (1.70) h and 13.73 (1.32) h, respectively. Plasma ET‐1 concentrations were dose‐proportional, whereas plasma TBA concentrations behaved erratically. Following a single 50 mg dose of SC0062 after a high‐fat meal, Cmax values for SC0062 and M18 increased by 41% and 32%, respectively, and median Tmax values for SC0062 were 3 h longer than fasting values; exposure was unaffected. These favorable safety, PK, and PD results provide a foundation for further studies of SC0062 in pulmonary arterial hypertension, chronic kidney disease, and other relevant indications.

Biodegradation, while cost-effective, is hindered by the requirement for specialized microorganisms and co-contaminants. Innovative biological technologies like the microbially driven Fenton reaction, hold promise for enhancing degradation efficiency. However, the intricate biochemical processes and essential steps for effective degradation in such systems have remained unclear. In this study, we harnessed the potential of the microbially driven Fenton reaction by employing Shewanella oneidensis MR-1 (MR-1). Our approach showcased remarkable efficacy in degrading a range of contaminants, including sulfadimethoxine (SDM), 4,4'-dibromodiphenyl ether (BDE-15) and atrazine (ATZ). Using SDM as a model contaminant of emergent contaminants (ECs), we unveiled that biodegradation relied on the generation of hydroxyl radicals (•OH) and involvement of oxidoreductases. Transcriptomic analysis shed light on the pivotal components of extracellular electron transfer (EET) during both anaerobic and aerobic periods. The presence of reactive oxidizing species induced cellular damage and impeded DNA repair, thereby affecting the Mtr pathway of EET. Moreover, the formation of vivianite hindered SDM degradation, underscoring the necessity of maintaining iron ions in the solution to ensure sustainable and efficient degradation. Overall, this study offers valuable insights into microbial technique for ECs degradation, providing a comprehensive understanding of degradation mechanisms during aerobic/anaerobic cycling.

Abstract This study aimed to assess the safety, pharmacokinetics, and food impact on sudapyridine (WX‐081), a novel drug designed to inhibit mycobacterium ATP synthase, with clinical applications for drug‐resistant tuberculosis (TB) treatment. The research comprised two arms: a single ascending dose (SAD) arm (30 to 600 mg, N = 52) and a multiple ascending dose (MAD) arm (200 to 400 mg, N = 30). The influence of food was evaluated using a 400 mg dose within an SAD cohort. Plasma concentrations of WX‐081 and M3 (main metabolite of WX‐081) were analyzed using a validated liquid‐chromatography tandem mass spectrometry method. In the SAD arm, mean residence time (MRT0‐t), terminal half‐life, and clearance of WX‐081 ranged from 18.87 to 52.8 h, 31.39 to 236.57 h, and 6.4 to 80.34 L/h, respectively. The area under the curve from time zero to the last measurable timepoint (AUC0‐t) of WX‐081 showed dose‐proportional increases in the SAD arm. The disparity between fasted and fed states of WX‐081 was significant (p < 0.05), with fed dosing resulting in a 984.07% higher AUC0‐t and 961.55% higher maximum plasma concentration. In both the SAD and MAD arms, one case each exhibited a 1 degree atrioventricular block. No QTc elongation was observed, and adverse events were not dose‐dependent. Favorable exposure, tolerability, safety, and an extended MRT0‐t suggest that WX‐081 holds promise as a phase II development candidate for drug‐resistant TB treatment.

Objective: This study aimed to investigate the feasibility of the efficacy and safety of TACE combined with Lenvatinib and PD-1 blockade in HCC with portal vein tumor thrombus (PVTT). Methods: Patients with HCC and PVTT who underwent TACE combined with Lenvatinib and PD-1 blockade as first-line therapy in clinical practice were retrospectively included. All subjects were followed-up regularly to obtain prognostic outcomes. The safety profile observed during the combination therapy was collected and documented. The Log rank test was used for exploratory analysis of prognosis and baseline characteristics and Cox regression analysis was used for multivariate analysis. Results: A total of 67 HCC patients with PVTT who received TACE combined with Lenvatinib and PD-1 blockade were included in this study. The best therapeutic response during treatment suggested that 4 patients achieved complete response, 30 patients showed partial response, 25 patients were stable disease, 5 patients had disease progression and 3 patients were not available. Objective response rate of this regimen was 50.7% [95% confidence interval (CI): 38.2-63.2%] and disease control rate was 88.1% (95% CI: 77.8-94.7%). The median progression-free survival of 67 HCC patients with PVTT who received TACE combined with Lenvatinib and PD-1 blockades was 9.3 months (95% CI: 5.85-12.75), and the median overall survival was 24.4 months (95% CI: 19.11-29.69). The safety profile highlighted that 65 patients experienced adverse reactions regardless of grade during treatment (97.0%), among whom 34 patients were deemed as grade >= 3 adverse reactions (50.7%). The most common adverse reactions were hypertension, fatigue, abnormal liver function, nausea, vomiting, and diarrhea. Overall adverse reactions were acceptable and controllable. Conclusion: TACE combined with Lenvatinib and PD-1 blockades as first-line therapy for HCC with PVTT demonstrated potential feasibility and encouraging clinical outcomes, providing long-term survival benefits for HCC patients. This conclusion should be confirmed in prospective large-scale clinical trials.

The aim of this study was to investigate the effect of a high‐fat meal on the single‐dose pharmacokinetics (PK) and tolerability of HMPL‐689 in Chinese healthy volunteers. In this study, 34 eligible male volunteers received a single 30‐mg dose of HMPL‐689 capsules following an overnight fast or a high‐fat breakfast prior to dosing. Blood samples were collected at the designated time points for pharmacokinetic analysis. Safety and tolerability were assessed throughout the study. Total 32 healthy male volunteers were completed in the study. The GMRs of AUC0−t, AUC0−∞, and Cmax and their 90% CIs were 1.12 (1.09, 1.15), 1.12 (1.09, 1.15), and 0.64 (0.58, 0.70), respectively, in healthy male subjects after oral administration of HMPL‐689 following intake of a high‐fat diet versus under fasting state. The 90% CI of Cmax GMR fell outside the acceptable equivalent range (0.8–1.25). In addition, the median Tmax of HMPL‐689 was 1.0 and 4.0 h under the fasting and the fed conditions. The study indicated that intake of a high‐fat diet had an impact on the in vivo PK profile of HMPL‐689 in healthy Chinese male subjects, which could obviously reduce the oral absorption rate of HMPL‐689 and had little effect on the extent of oral absorption (AUC).

Supplementary information (figures and tables) for "Role of DNMT1 and C/EBPα in the regulation CYP11A1 expression during syncytialization of human placental trophoblasts" by Ya-Nan Zhu, Fan Pan, Xiao-Wen Gan, Yun Liu, Wang-Sheng Wang*, Kang Sun*

The present study evaluated the safety, tolerability, and pharmacokinetics of fluoropezil (DC20), a novel acetylcholinesterase inhibitor under development for the treatment of Alzheimer's disease (AD) in otherwise healthy young and elderly Chinese subjects. The study of young subjects included the multiple ascending dose (MAD) arm (2 and 6 mg, N = 24) and the food effect arm (4 mg, N = 12) and was followed by the study of elderly subjects who were given (2 and 4 mg, N = 11). The noncompartmental analysis method was used to determine the pharmacokinetic parameters. The pharmacokinetics of fed versus fasted dose administration in the same subjects was assessed by 90% confidence interval. In the MAD arm, the accumulation ratios of DC20 in vivo were 2.29 and 2.15, respectively. In the food effect arm, compared with fasting administration, an area under the concentration-time curve from zero to t after a standard and high-fat diet orally administered slightly increased by about 19% and 29%, and the time to maximum concentration (T-max) was delayed by around 1 h. For elderly study subjects, T-max was 1.5 and 1.25 h, and terminal half-life (t(1/2)) was 77.1 and 74.2 h, respectively. There were no serious adverse events (AEs), whereas gastrointestinal reactions were the most common AEs associated with the study drug. We predicted the safety risks of DC20 in the clinical treatment of AD, which were well-tolerated by the healthy young and elderly subjects. The elimination of DC20 from the body was slower in elderly subjects than in young subjects. This study was approved by the Center for Drug Evaluation, National Medical Products Administration (CTR20181428, CTR20190664, CTR20191878, and CTR20192724).

The bioequivalence and safety of levetiracetam granules (test formulation) and oral solution (reference formulation) were evaluated in Chinese healthy volunteers under a fasting condition. A total of 24 subjects randomly received the test or reference formulation at the rate of 1:1. The alternative formulation was administered after a 7-day washout period. The blood samples were collected at designated time points. Liquid chromatography–tandem mass spectrometry was applied to determine the plasma concentrations of levetiracetam. Adverse events were monitored and recorded. The 90% CIs for the geometric mean ratios of maximum plasma concentration, area under the plasma concentration–time curve from time 0 to the last quantifiable concentration, and area under the plasma concentration-time curve from time 0 to infinity between test preparation and reference preparation were 95.5% to 110.7%, 100.2% to 105.3%, and 100.3% to 105.7%, respectively, all within an acceptable bioequivalence range of 80.00% 125.00%. Both test and reference preparations were well tolerated. The trial confirmed that a single dose of 500-mg levetiracetam granules was bioequivalent to oral solution under a fasting condition, and may serve as a new dosage form of levetiracetam for clinical practice.

Short-chain fatty acids (SCFAs) produced by the gut microbiota have been well demonstrated to improve metabolic homeostasis. However, the role of SCFAs in islet function remains controversial. In the present study, none of the sodium acetate, sodium propionate, and sodium butyrate (SB) displayed acute impacts on insulin secretion from rat islets, whereas long-term incubation of the three SCFAs significantly potentiated pancreatic β cell function. RNA sequencing (RNA-seq) revealed an unusual transcriptome change in SB-treated rat islets, with the downregulation of insulin secretion pathway and β cell identity genes, including Pdx1, MafA, NeuroD1, Gck, and Slc2a2. But these β cell identity genes were not governed by the pan-HDAC inhibitor trichostatin A. Overlapping analysis of H3K27Ac ChIP-seq and RNA-seq showed that the inhibitory effect of SB on the expression of multiple β cell identity genes was independent of H3K27Ac. SB treatment increased basal oxygen consumption rate (OCR), but attenuated glucose-stimulated OCR in rat islets, without altering the expressions of genes involved in glycolysis and tricarboxylic acid cycle. SB reduced the expression of Kcnj11 (encoding K ATP channel) and elevated basal intracellular calcium concentration. On the other hand, SB elicited insulin gene expression in rat islets through increasing H3K18bu occupation in its promoter, without stimulating CREB phosphorylation. These findings indicate that SB potentiates islet function as a lipid molecule at the expense of compromised expression of islet β cell identity genes.

The bioequivalence and safety of levetiracetam granules (test formulation) and oral solution (reference formulation) were evaluated in Chinese healthy volunteers under a fasting condition. A total of 24 subjects randomly received the test or reference formulation at the rate of 1:1. The alternative formulation was administered after a 7-day washout period. The blood samples were collected at designated time points. Liquid chromatography-tandem mass spectrometry was applied to determine the plasma concentrations of levetiracetam. Adverse events were monitored and recorded. The 90% CIs for the geometric mean ratios of maximum plasma concentration, area under the plasma concentration-time curve from time 0 to the last quantifiable concentration, and area under the plasma concentration-time curve from time 0 to infinity between test preparation and reference preparation were 95.5% to 110.7%, 100.2% to 105.3%, and 100.3% to 105.7%, respectively, all within an acceptable bioequivalence range of 80.00% 125.00%. Both test and reference preparations were well tolerated. The trial confirmed that a single dose of 500-mg levetiracetam granules was bioequivalent to oral solution under a fasting condition, and may serve as a new dosage form of levetiracetam for clinical practice.

Loss of β cell identity and functional immaturity are thought to be involved in β cell failure in type 2 diabetes. CREB-binding protein (CBP) and its paralogue p300 act as multifunctional transcriptional co-activators and histone acetyltransferases (HAT) with extensive biological functions. However, whether the regulatory role of CBP/p300 in islet β cell function depends on the HAT activity remains uncertain. In this current study, A-485, a selective inhibitor of CBP/p300 HAT activity, greatly impaired glucose-stimulated insulin secretion from rat islets in vitro and in vivo. RNA-sequencing analysis showed a comprehensive downregulation of β cell and α cell identity genes in A-485-treated islets, without upregulation of dedifferentiation markers and derepression of disallowed genes. A-485 treatment decreased the expressions of genes involved in glucose sensing, not in glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation. In the islets of prediabetic db/db mice, CBP/p300 displayed a significant decrease with key genes for β cell function. The deacetylation of histone H3K27 as well as the transcription factors Hnf1α and Foxo1 was involved in CBP/p300 HAT inactivation-repressed expressions of β cell identity and functional genes. These findings highlight the dominant role of CBP/p300 HAT in the maintenance of β cell identity by governing transcription network.

Rationale: Sirtuins are NAD+-dependent protein deacylases known to have protective effects against age-related diseases such as diabetes, cancer, and neurodegenerative disease. SIRT2 is the only primarily cytoplasmic isoform and its overall role in glucose homeostasis remains uncertain. Methods: SIRT2-knockout (KO) rats were constructed to evaluate the role of SIRT2 in glucose homeostasis. The effect of SIRT2 on β-cell function was detected by investigating the morphology, insulin secretion, and metabolomic state of islets. The deacetylation and stabilization of GKRP in β-cells by SIRT2 were determined by western blot, adenoviral infection, and immunoprecipitation. Results: SIRT2-KO rats exhibited impaired glucose tolerance and glucose-stimulated insulin secretion (GSIS), without change in insulin sensitivity. SIRT2 deficiency or inhibition by AGK2 decreased GSIS in isolated rat islets, with lowered oxygen consumption rate. Adenovirus-mediated overexpression of SIRT2 enhanced insulin secretion from rat islets. Metabolomics analysis revealed a decrease in metabolites of glycolysis and tricarboxylic acid cycle in SIRT2-KO islets compared with control islets. Our study further demonstrated that glucokinase regulatory protein (GKRP), an endogenous inhibitor of glucokinase (GCK), was expressed in rat islets. SIRT2 overexpression deacetylated GKRP in INS-1 β-cells. SIRT2 knockout or inhibition elevated GKRP protein stability in islet β-cells, leading to an increase in the interaction of GKRP and GCK. On the contrary, SIRT2 inhibition promoted the protein degradation of ALDOA, a glycolytic enzyme. Conclusions: SIRT2 ablation inhibits GSIS through blocking GKRP protein degradation and promoting ALDOA protein degradation, resulting in a decrease in glycolytic flux.