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1.
Cardiovasc Diabetol ; 23(1): 228, 2024 Jun 29.
Article in English | MEDLINE | ID: mdl-38951793

ABSTRACT

BACKGROUND: Glucokinase (GK) plays a key role in glucose metabolism. In the liver, GK is regulated by GK regulatory protein (GKRP) with nuclear sequestration at low plasma glucose level. Some GK activators (GKAs) disrupt GK-GKRP interaction which increases hepatic cytoplasmic GK level. Excess hepatic GK activity may exceed the capacity of glycogen synthesis with excess triglyceride formation. It remains uncertain whether hypertriglyceridemia associated with some GKAs in previous clinical trials was due to direct GK activation or impaired GK-GKRP interaction. METHODS: Using publicly available genome-wide association study summary statistics, we selected independent genetic variants of GCKR and GCK associated with fasting plasma glucose (FPG) as instrumental variables, to mimic the effects of impaired GK-GKRP interaction and direct GK activation, respectively. We applied two-sample Mendelian Randomization (MR) framework to assess their causal associations with lipid-related traits, risks of metabolic dysfunction-associated steatotic liver disease (MASLD) and cardiovascular diseases. We verified these findings in one-sample MR analysis using individual-level statistics from the Hong Kong Diabetes Register (HKDR). RESULTS: Genetically-proxied impaired GK-GKRP interaction increased plasma triglycerides, low-density lipoprotein cholesterol and apolipoprotein B levels with increased odds ratio (OR) of 14.6 (95% CI 4.57-46.4) per 1 mmol/L lower FPG for MASLD and OR of 2.92 (95% CI 1.78-4.81) for coronary artery disease (CAD). Genetically-proxied GK activation was associated with decreased risk of CAD (OR 0.69, 95% CI 0.54-0.88) and not with dyslipidemia. One-sample MR validation in HKDR showed consistent results. CONCLUSIONS: Impaired GK-GKRP interaction, rather than direct GK activation, may worsen lipid profiles and increase risks of MASLD and CAD. Development of future GKAs should avoid interfering with GK-GKRP interaction.


Subject(s)
Adaptor Proteins, Signal Transducing , Blood Glucose , Genetic Predisposition to Disease , Genome-Wide Association Study , Glucokinase , Mendelian Randomization Analysis , Humans , Adaptor Proteins, Signal Transducing/genetics , Risk Factors , Risk Assessment , Blood Glucose/metabolism , Glucokinase/genetics , Glucokinase/metabolism , Biomarkers/blood , Lipids/blood , Phenotype , Carrier Proteins/genetics , Carrier Proteins/metabolism , Polymorphism, Single Nucleotide , Time Factors , Dyslipidemias/genetics , Dyslipidemias/blood , Dyslipidemias/diagnosis , Dyslipidemias/epidemiology , Dyslipidemias/enzymology , Fatty Liver/genetics , Fatty Liver/enzymology , Fatty Liver/blood
2.
Molecules ; 29(13)2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38998908

ABSTRACT

Cooperation between catabolism and anabolism is crucial for maintaining homeostasis in living cells. The most fundamental systems for catabolism and anabolism are the glycolysis of sugars and the transcription-translation (TX-TL) of DNA, respectively. Despite their importance in living cells, the in vitro reconstitution of their cooperation through purified factors has not been achieved, which hinders the elucidation of the design principle in living cells. Here, we reconstituted glycolysis using sugars and integrated it with the PURE system, a commercial in vitro TX-TL kit composed of purified factors. By optimizing key parameters, such as glucokinase and initial phosphate concentrations, we determined suitable conditions for their cooperation. The optimized system showed protein synthesis at up to 33% of that of the original PURE system. We observed that ATP consumption in upstream glycolysis inhibits TX-TL and that this inhibition can be alleviated by the co-addition of glycolytic intermediates, such as glyceraldehyde 3-phosphate, with glucose. Moreover, the system developed here simultaneously synthesizes a subset of its own enzymes, that is, glycolytic enzymes, in a single test tube, which is a necessary step toward self-replication. As glycolysis and TX-TL provide building blocks for constructing cells, the integrated system can be a fundamental material for reconstituting living cells from purified factors.


Subject(s)
Cell-Free System , Glycolysis , Protein Biosynthesis , Transcription, Genetic , Glucose/metabolism , Adenosine Triphosphate/metabolism , Sugars/metabolism , Glucokinase/metabolism , Glucokinase/genetics
3.
Antiviral Res ; 228: 105939, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38909960

ABSTRACT

Viruses have developed sophisticated strategies to control metabolic activity of infected cells in order to supply replication machinery with energy and metabolites. Dengue virus (DENV), a mosquito-borne flavivirus responsible for dengue fever, is no exception. Previous reports have documented DENV interactions with metabolic pathways and shown in particular that glycolysis is increased in DENV-infected cells. However, underlying molecular mechanisms are still poorly characterized and dependence of DENV on this pathway has not been investigated in details yet. Here, we identified an interaction between the non-structural protein 3 (NS3) of DENV and glucokinase regulator protein (GCKR), a host protein that inhibits the liver-specific hexokinase GCK. NS3 expression was found to increase glucose consumption and lactate secretion in hepatic cell line expressing GCK. Interestingly, we observed that GCKR interaction with GCK decreases DENV replication, indicating the dependence of DENV to GCK activity and supporting the role of NS3 as an inhibitor of GCKR function. Accordingly, in the same cells, DENV replication both induces and depends on glycolysis. By targeting NAD(H) biosynthesis with the antimetabolite 6-Amino-Nicotinamide (6-AN), we decreased cellular glycolytic activity and inhibited DENV replication in hepatic cells. Infection of primary organotypic liver cultures (OLiC) from hamsters was also inhibited by 6-AN. Altogether, our results show that DENV has evolved strategies to control glycolysis in the liver, which could account for hepatic dysfunctions associated to infection. Besides, our findings suggest that lowering intracellular availability of NAD(H) could be a valuable therapeutic strategy to control glycolysis and inhibit DENV replication in the liver.


Subject(s)
Dengue Virus , Dengue , Glucokinase , Glycolysis , NAD , Viral Nonstructural Proteins , Virus Replication , Glycolysis/drug effects , Dengue Virus/drug effects , Glucokinase/metabolism , Glucokinase/antagonists & inhibitors , Humans , Virus Replication/drug effects , Viral Nonstructural Proteins/metabolism , Viral Nonstructural Proteins/genetics , Animals , Dengue/drug therapy , Dengue/virology , Dengue/metabolism , NAD/metabolism , NAD/biosynthesis , Cell Line , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Glucose/metabolism , Liver/virology , Liver/metabolism , Antiviral Agents/pharmacology , Viral Proteases , Serine Endopeptidases , Nucleoside-Triphosphatase , DEAD-box RNA Helicases
4.
PLoS One ; 19(6): e0303934, 2024.
Article in English | MEDLINE | ID: mdl-38875221

ABSTRACT

The nerve growth factor (NGF) participates in cell survival and glucose-stimulated insulin secretion (GSIS) processes in rat adult beta cells. GSIS is a complex process in which metabolic events and ionic channel activity are finely coupled. GLUT2 and glucokinase (GK) play central roles in GSIS by regulating the rate of the glycolytic pathway. The biphasic release of insulin upon glucose stimulation characterizes mature adult beta cells. On the other hand, beta cells obtained from neonatal, suckling, and weaning rats are considered immature because they secrete low levels of insulin and do not increase insulin secretion in response to high glucose. The weaning of rats (at postnatal day 20 in laboratory conditions) involves a dietary transition from maternal milk to standard chow. It is characterized by increased basal plasma glucose levels and insulin levels, which we consider physiological insulin resistance. On the other hand, we have observed that incubating rat beta cells with NGF increases GSIS by increasing calcium currents in neonatal cells. In this work, we studied the effects of NGF on the regulation of cellular distribution and activity of GLUT2 and GK to explore its potential role in the maturation of GSIS in beta cells from P20 rats. Pancreatic islet cells from both adult and P20 rats were isolated and incubated with 5.6 mM or 15.6 mM glucose with and without NGF for 4 hours. Specific immunofluorescence assays were conducted following the incubation period to detect insulin and GLUT2. Additionally, we measured glucose uptake, glucokinase activity, and insulin secretion assays at 5.6 mM or 15.6 mM glucose concentrations. We observed an age-dependent variation in the distribution of GLUT2 in pancreatic beta cells and found that glucose plays a regulatory role in GLUT2 distribution independently of age. Moreover, NGF increases GLUT2 abundance, glucose uptake, and GSIS in P20 beta cells and GK activity in adult beta cells. Our results suggest that besides increasing calcium currents, NGF regulates metabolic components of the GSIS, thereby contributing to the maturation process of pancreatic beta cells.


Subject(s)
Glucokinase , Glucose Transporter Type 2 , Glucose , Insulin-Secreting Cells , Nerve Growth Factor , Animals , Male , Rats , Cells, Cultured , Glucokinase/metabolism , Glucose/metabolism , Glucose Transporter Type 2/metabolism , Insulin/metabolism , Insulin Secretion/drug effects , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/drug effects , Nerve Growth Factor/metabolism , Nerve Growth Factor/pharmacology , Rats, Wistar
5.
Diabetes Care ; 47(7): 1140-1142, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38691834

ABSTRACT

OBJECTIVE: Metformin, insulin, and insulin secretagogues do not alter HbA1c levels in glucokinase maturity-onset diabetes of the young (GCK-MODY). However, the efficacy of the new hypoglycemic drugs on GCK-MODY remains unclear. RESEARCH DESIGN AND METHODS: We describe a case of GCK-MODY with unchanged blood glucose under different therapies during an 8 years' follow-up. His HbA1c and biochemical indices under different hypoglycemic treatments were recorded. RESULTS: Oral glucose-lowering drugs, including thiazolidinediones, dipeptidyl peptidase 4 inhibitor, α-glucosidase inhibitor, and sodium-glucose cotransporter 2 inhibitor that had not been evaluated previously, did not improve the HbA1c level in this patient. However, the glucokinase activator dorzagliatin effectively and safely lowered his HbA1c level. CONCLUSIONS: Dorzagliatin was effective and safe in this patient with GCK-MODY, providing potential application prospects for precise treatment of GCK-MODY with dorzagliatin.


Subject(s)
Diabetes Mellitus, Type 2 , Hypoglycemic Agents , Humans , Male , Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/therapeutic use , Blood Glucose/drug effects , Blood Glucose/metabolism , Glycated Hemoglobin/metabolism , Adult , Glucokinase/metabolism , Glycosides
6.
ACS Chem Neurosci ; 15(11): 2350-2358, 2024 06 05.
Article in English | MEDLINE | ID: mdl-38757688

ABSTRACT

Growth hormone-releasing hormone (Ghrh) neurons in the dorsomedial ventromedial hypothalamic nucleus (VMNdm) express the metabolic transcription factor steroidogenic factor-1 and hypoglycemia-sensitive neurochemicals of diverse chemical structures, transmission modes, and temporal signaling profiles. Ghrh imposes neuromodulatory control of coexpressed transmitters. Multiple metabolic sensory mechanisms are employed in the brain, including screening of the critical nutrient glucose or the energy currency ATP. Here, combinatory laser-catapult-microdissection/single-cell multiplex qPCR tools were used to investigate whether these neurons possess molecular machinery for monitoring cellular metabolic status and if these biomarkers exhibit sex-specific sensitivity to insulin-induced hypoglycemia. Data show that hypoglycemia up- (male) or downregulated (female) Ghrh neuron glucokinase (Gck) mRNA; Ghrh gene silencing decreased baseline and hypoglycemic patterns of Gck gene expression in each sex. Ghrh neuron glucokinase regulatory protein (Gckr) transcript levels were respectively diminished or augmented in hypoglycemic male vs female rats; this mRNA profile was decreased by Ghrh siRNA in both sexes. Gene transcripts encoding catalytic alpha subunits of the energy monitor 5-AMP-activated protein kinase (AMPK), i.e., Prkaa1 and 2, were increased by hypoglycemia in males, yet only the former mRNA was hypoglycemia-sensitive in females. Ghrh siRNA downregulated baseline and hypoglycemia-associated Prkaa subunit mRNAs in males but elicited divergent changes in Prkaa2 transcripts in eu- vs hypoglycemic females. Results provide unique evidence that VMNdm Ghrh neurons express the characterized metabolic sensor biomarkers glucokinase and AMPK and that the corresponding gene profiles exhibit distinctive sex-dimorphic transcriptional responses to hypoglycemia. Data further document Ghrh neuromodulation of baseline and hypoglycemic transcription patterns of these metabolic gene profiles.


Subject(s)
Hypoglycemia , Neurons , RNA, Messenger , Sex Characteristics , Ventromedial Hypothalamic Nucleus , Animals , Female , Male , Rats , Dorsomedial Hypothalamic Nucleus/metabolism , Glucokinase/metabolism , Glucokinase/genetics , Growth Hormone-Releasing Hormone/metabolism , Growth Hormone-Releasing Hormone/genetics , Hypoglycemia/metabolism , Neurons/metabolism , Rats, Sprague-Dawley , RNA, Messenger/metabolism , Ventromedial Hypothalamic Nucleus/metabolism
7.
J Diabetes ; 16(6): e13563, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38783768

ABSTRACT

Type 2 diabetes mellitus (T2DM) is a complicated disease related to metabolism that results from resistance to insulin and sustained hyperglycemia. Traditional antidiabetic drugs cannot meet the demand of different diabetes patients for reaching the glycemic targets; thus, the identification of new antidiabetic drugs is urgently needed for the treatment of T2DM to enhance glycemic control and the prognosis of patients suffering from T2DM. Recently, glucokinase (GK) has attracted much attention and is considered to be an effective antidiabetic agent. Glucokinase activators (GKA) represented by dorzagliatin could activate GK and mimic its function that triggers a counter-regulatory response to blood glucose changes. Dorzagliatin has shown great potential for glycemic control in diabetic patients in a randomized, double-blind, placebo-controlled Phase 3 trial (SEED study) and had a favorable safety profile and was well tolerated (DAWN study). In the SEED study, dorzagliatin significantly reduced glycosylated hemoglobin (HbA1c) by 1.07% and postprandial blood glucose by 2.83 mol/L, showing the great potential of this drug to control blood glucose in diabetic patients, with good safety and good tolerance. An extension of the SEED study, the DREAM study, confirmed that dorzagliatin monotherapy significantly improved 24-h glucose variability and increased time in range (TIR) to 83.7% over 46 weeks. Finally, the clinical study of dorzagliatin combined with metformin (DAWN study) confirmed that dorzagliatin could significantly reduce HbA1c by 1.02% and postprandial blood glucose by 5.45 mol/L. The current review summarizes the development of GK and GKA, as well as the prospects, trends, applications, and shortcomings of these treatments, especially future directions of clinical studies of dorzagliatin.


Subject(s)
Diabetes Mellitus, Type 2 , Glucokinase , Hypoglycemic Agents , Humans , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/blood , Hypoglycemic Agents/therapeutic use , Glucokinase/metabolism , Blood Glucose/drug effects , Blood Glucose/metabolism , Drug Development , Enzyme Activators/therapeutic use , Glycated Hemoglobin/metabolism , Glycated Hemoglobin/analysis
8.
Sci Rep ; 14(1): 10589, 2024 05 08.
Article in English | MEDLINE | ID: mdl-38719926

ABSTRACT

Maturity Onset Diabetes of the Young (MODY) is a young-onset, monogenic form of diabetes without needing insulin treatment. Diagnostic testing is expensive. To aid decisions on who to test, we aimed to develop a MODY probability calculator for paediatric cases at the time of diabetes diagnosis, when the existing "MODY calculator" cannot be used. Firth logistic regression models were developed on data from 3541 paediatric patients from the Swedish 'Better Diabetes Diagnosis' (BDD) population study (n = 46 (1.3%) MODY (HNF1A, HNF4A, GCK)). Model performance was compared to using islet autoantibody testing. HbA1c, parent with diabetes, and absence of polyuria were significant independent predictors of MODY. The model showed excellent discrimination (c-statistic = 0.963) and calibrated well (Brier score = 0.01). MODY probability > 1.3% (ie. above background prevalence) had similar performance to being negative for all 3 antibodies (positive predictive value (PPV) = 10% v 11% respectively i.e. ~ 1 in 10 positive test rate). Probability > 1.3% and negative for 3 islet autoantibodies narrowed down to 4% of the cohort, and detected 96% of MODY cases (PPV = 31%). This MODY calculator for paediatric patients at time of diabetes diagnosis will help target genetic testing to those most likely to benefit, to get the right diagnosis.


Subject(s)
Diabetes Mellitus, Type 2 , Humans , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/genetics , Child , Male , Female , Adolescent , Hepatocyte Nuclear Factor 4/genetics , Hepatocyte Nuclear Factor 1-alpha/genetics , Child, Preschool , Autoantibodies/blood , Autoantibodies/immunology , Glycated Hemoglobin/analysis , Germinal Center Kinases/genetics , Sweden , Glucokinase/genetics
9.
Acta Diabetol ; 61(7): 917-924, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38565685

ABSTRACT

AIMS: Previous structural, vascular density, and perfusion studies have mostly comprised type 1 and type 2 diabetes, even in the absence of retinopathy. The current study aimed to compare macular vessel density (VD) measurements between maturity-onset diabetes of the young (MODY) patients and controls. METHODS: The macular VD of superficial, deep retina, and choriocapillaris (CC), and central macular thickness (CMT), foveal avascular zone (FAZ), FAZ perimetry, VD of the total retina at 300 µm around the FAZ (FD), and acirculatory index (AI) measurements were taken and analyzed via OCT-A (RTVue XR 100-2 Avanti, AngioVue) and were compared between molecularly confirmed MODY (glucokinase (GCK) variants) patients and healthy controls. RESULTS: Twenty-five MODY patients and 30 healthy controls were included in the study. The mean plasma hemoglobin A1c level in the MODY group was 6.39 ± 0.38. The mean age was 13.8 ± 2.1 in the MODY group and was 12.6 ± 2.5 years among controls. There was no significant difference in terms of the age, superficial and deep retinal VD, FAZ, FAZ perimetry, CMT, FD, or AI between the groups. Compared to the healthy controls, a slight but significant increase in the CC-VD was detected in the MODY group, but only in the parafoveal and perifoveal regions (p = 0.034, p = 0.009). CONCLUSION: The significant CC-VD increase in the MODY group might be associated with hyperglycemia and/or relatively poor and vulnerable peripheral vascular CC perfusion compared to the central. Previous thickness and VD results of childhood or adolescent diabetes were distributed in a wider range, suggesting that various factors, including some not yet clearly defined, may affect the choroidal vasculature independently of glycemia or as a contributing factor.


Subject(s)
Diabetes Mellitus, Type 2 , Retinal Vessels , Tomography, Optical Coherence , Humans , Tomography, Optical Coherence/methods , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/diagnostic imaging , Male , Female , Adolescent , Child , Case-Control Studies , Retinal Vessels/diagnostic imaging , Diabetic Retinopathy/diagnostic imaging , Diabetic Retinopathy/diagnosis , Diabetic Retinopathy/genetics , Young Adult , Fluorescein Angiography/methods , Glucokinase/genetics , Macula Lutea/diagnostic imaging , Macula Lutea/blood supply
11.
J Diabetes ; 16(5): e13544, 2024 May.
Article in English | MEDLINE | ID: mdl-38664885

ABSTRACT

As a sensor, glucokinase (GK) controls glucose homeostasis, which progressively declines in patients with diabetes. GK maintains the equilibrium of glucose levels and regulates the homeostatic system set points. Endocrine and hepatic cells can both respond to glucose cooperatively when GK is activated. GK has been under study as a therapeutic target for decades due to the possibility that cellular GK expression and function can be recovered, hence restoring glucose homeostasis in patients with type 2 diabetes. Five therapeutic compounds targeting GK are being investigated globally at the moment. They all have distinctive molecular structures and have been clinically shown to have strong antihyperglycemia effects. The mechanics, classification, and clinical development of GK activators are illustrated in this review. With the recent approval and marketing of the first GK activator (GKA), dorzagliatin, GKA's critical role in treating glucose homeostasis disorder and its long-term benefits in diabetes will eventually become clear.


Subject(s)
Diabetes Mellitus, Type 2 , Glucokinase , Homeostasis , Humans , Glucokinase/metabolism , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Enzyme Activators/therapeutic use , Enzyme Activators/pharmacology , Hypoglycemic Agents/therapeutic use , Hypoglycemic Agents/pharmacology , Blood Glucose/metabolism , Animals , Glucose/metabolism
12.
Int J Mol Sci ; 25(8)2024 Apr 13.
Article in English | MEDLINE | ID: mdl-38673904

ABSTRACT

Chagas disease is one of the world's neglected tropical diseases, caused by the human pathogenic protozoan parasite Trypanosoma cruzi. There is currently a lack of effective and tolerable clinically available therapeutics to treat this life-threatening illness and the discovery of modern alternative options is an urgent matter. T. cruzi glucokinase (TcGlcK) is a potential drug target because its product, d-glucose-6-phosphate, serves as a key metabolite in the pentose phosphate pathway, glycolysis, and gluconeogenesis. In 2019, we identified a novel cluster of TcGlcK inhibitors that also exhibited anti-T. cruzi efficacy called the 3-nitro-2-phenyl-2H-chromene analogues. This was achieved by performing a target-based high-throughput screening (HTS) campaign of 13,040 compounds. The selection criteria were based on first determining which compounds strongly inhibited TcGlcK in a primary screen, followed by establishing on-target confirmed hits from a confirmatory assay. Compounds that exhibited notable in vitro trypanocidal activity over the T. cruzi infective form (trypomastigotes and intracellular amastigotes) co-cultured in NIH-3T3 mammalian host cells, as well as having revealed low NIH-3T3 cytotoxicity, were further considered. Compounds GLK2-003 and GLK2-004 were determined to inhibit TcGlcK quite well with IC50 values of 6.1 µM and 4.8 µM, respectively. Illuminated by these findings, we herein screened a small compound library consisting of thirteen commercially available 3-nitro-2-phenyl-2H-chromene analogues, two of which were GLK2-003 and GLK2-004 (compounds 1 and 9, respectively). Twelve of these compounds had a one-point change from the chemical structure of GLK2-003. The analogues were run through a similar primary screening and confirmatory assay protocol to our previous HTS campaign. Subsequently, three in vitro biological assays were performed where compounds were screened against (a) T. cruzi (Tulahuen strain) infective form co-cultured within NIH-3T3 cells, (b) T. brucei brucei (427 strain) bloodstream form, and (c) NIH-3T3 host cells alone. We report on the TcGlcK inhibitor constant determinations, mode of enzyme inhibition, in vitro antitrypanosomal IC50 determinations, and an assessment of structure-activity relationships. Our results reveal that the 3-nitro-2-phenyl-2H-chromene scaffold holds promise and can be further optimized for both Chagas disease and human African trypanosomiasis early-stage drug discovery research.


Subject(s)
Benzopyrans , Glucokinase , Trypanocidal Agents , Trypanosoma cruzi , Animals , Humans , Mice , Benzopyrans/pharmacology , Benzopyrans/chemistry , Chagas Disease/drug therapy , Chagas Disease/parasitology , Drug Discovery/methods , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry , Glucokinase/metabolism , Glucokinase/antagonists & inhibitors , High-Throughput Screening Assays , Molecular Docking Simulation , NIH 3T3 Cells , Structure-Activity Relationship , Trypanocidal Agents/pharmacology , Trypanocidal Agents/chemistry , Trypanosoma cruzi/drug effects , Trypanosoma cruzi/enzymology , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology
13.
Genome Biol ; 25(1): 98, 2024 04 16.
Article in English | MEDLINE | ID: mdl-38627865

ABSTRACT

BACKGROUND: Amino acid substitutions can perturb protein activity in multiple ways. Understanding their mechanistic basis may pinpoint how residues contribute to protein function. Here, we characterize the mechanisms underlying variant effects in human glucokinase (GCK) variants, building on our previous comprehensive study on GCK variant activity. RESULTS: Using a yeast growth-based assay, we score the abundance of 95% of GCK missense and nonsense variants. When combining the abundance scores with our previously determined activity scores, we find that 43% of hypoactive variants also decrease cellular protein abundance. The low-abundance variants are enriched in the large domain, while residues in the small domain are tolerant to mutations with respect to abundance. Instead, many variants in the small domain perturb GCK conformational dynamics which are essential for appropriate activity. CONCLUSIONS: In this study, we identify residues important for GCK metabolic stability and conformational dynamics. These residues could be targeted to modulate GCK activity, and thereby affect glucose homeostasis.


Subject(s)
Diabetes Mellitus, Type 2 , Glucokinase , Humans , Amino Acid Substitution , Diabetes Mellitus, Type 2/genetics , Glucokinase/genetics , Glucokinase/chemistry , Glucokinase/metabolism , Mutation
14.
Bioorg Med Chem ; 103: 117695, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38522346

ABSTRACT

Resveratrol oligomers, ranging from dimers to octamers, are formed through regioselective synthesis involving the phenoxy radical coupling of resveratrol building blocks, exhibiting remarkable therapeutic potential, including antidiabetic properties. In this study, we elucidate the mechanistic insights into the insulin secretion potential of a resveratrol dimer, (-)-Ampelopsin F (AmF), isolated from the acetone extract of Vatica chinensis L. stem bark in Pancreatic Beta-TC-6 cell lines. The AmF (50 µM) treated cells exhibited a 3.5-fold increase in insulin secretion potential as compared to unstimulated cells, which was achieved through the enhancement of mitochondrial membrane hyperpolarization, elevation of intracellular calcium concentration, and upregulation of GLUT2 and glucokinase expression in pancreatic Beta-TC-6 cell lines. Furthermore, AmF effectively inhibited the activity of DPP4, showcasing a 2.5-fold decrease compared to the control and a significant 6.5-fold reduction compared to the positive control. These findings emphasize AmF as a potential lead for the management of diabetes mellitus and point to its possible application in the next therapeutic initiatives.


Subject(s)
Flavonoids , Insulin-Secreting Cells , Insulin Secretion , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Resveratrol , Glucokinase/metabolism , Glucose/metabolism
15.
Clin Drug Investig ; 44(4): 223-250, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38460077

ABSTRACT

Despite advances in the management of type 2 diabetes mellitus (T2DM), one-third of patients with diabetes do not achieve the desired glycemic goal. Considering this inadequacy, many agents that activate glucokinase have been investigated over the last two decades but were withdrawn before submission for marketing permission. Dorzagliatin is the first glucokinase activator that has been granted approval for T2DM, only in China. As overstimulation of glucokinase is linked with pathophysiological disturbances such as fatty liver and cardiovascular issues and a loss of therapeutic efficacy with time. This review aims to highlight the benefits of glucokinase activators vis-à-vis the risks associated with chronic enzymatic activation. We discuss the multisystem disturbances expected with chronic activation of the enzyme, the lessons learned with glucokinase activators of the past, the major efficacy and safety findings with dorzagliatin and its pharmacological properties, and the status of other glucokinase activators in the pipeline. The approval of dorzagliatin in China was based on the SEED and the DAWN trials, the major pivotal phase III trials that enrolled patients with T2DM with a mean glycosylated hemoglobin of 8.3-8.4%, and a mean age of 53-54.5 years from multiple sites in China. Patients with uncontrolled diabetes, cardiac diseases, organ dysfunction, and a history of severe hypoglycemia were excluded. Both trials had a randomized double-blind placebo-controlled phase of 24 weeks followed by an open-label phase of 28 weeks with dorzagliatin. Drug-naïve patients with T2DM with a disease duration of 11.7 months were enrolled in the SEED trial while the DAWN trial involved patients with T2DM with a mean duration of 71.5 months and receiving background metformin therapy. Compared with placebo, the decline in glycosylated hemoglobin at 24 weeks was more with dorzagliatin with an estimated treatment difference of - 0.57% in the SEED trial and - 0.66% in the DAWN trial. The desired glycosylated hemoglobin (< 7%) was also attained at more than two times higher rates with dorzagliatin. The glycemic improvement was sustained in the SEED trial but decreased over 52 weeks in the DAWN trial. Hyperlipidemia was observed in 12-14% of patients taking dorzagliatin versus 9-11% of patients receiving a placebo. Additional adverse effects noticed over 52 weeks with dorzagliatin included an elevation in liver enzymes, hyperuricemia, hyperlacticacidemia, renal dysfunction, and cardiovascular disturbances. Considering the statistically significant improvement in glycosylated hemoglobin with dorzagliatin in patients with T2DM, the drug may be given a chance in treatment-naïve patients with a shorter disease history. However, with the waning therapeutic efficacy witnessed in patients with long-standing diabetes, which was also one of the potential concerns with previously tested molecules, extended studies involving patients with chronic and uncontrolled diabetes are needed to comment upon the long-term therapeutic performance of dorzagliatin. Likewise, evidence needs to be generated from other countries, patients with organ dysfunction, a history of severe hypoglycemia, cardiac diseases, and elderly patients before extending the use of dorzagliatin. Apart from monitoring lipid profiles, long-term safety studies of dorzagliatin should involve the assessment of serum uric acid, lactate, renal function, liver function, and cardiovascular parameters.


Subject(s)
Diabetes Mellitus, Type 2 , Heart Diseases , Hypoglycemia , Pyrazoles , Humans , Aged , Middle Aged , Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/adverse effects , Glycated Hemoglobin , Glucokinase , Multiple Organ Failure/chemically induced , Multiple Organ Failure/drug therapy , Uric Acid , Hypoglycemia/chemically induced , Hypoglycemia/drug therapy , Heart Diseases/chemically induced , Heart Diseases/drug therapy , Blood Glucose , Randomized Controlled Trials as Topic
16.
Medicine (Baltimore) ; 103(8): e36916, 2024 Feb 23.
Article in English | MEDLINE | ID: mdl-38394489

ABSTRACT

OBJECT: To evaluate the efficacy and safety of dorzagliatin for the treatment of type 2 diabetes (T2DM). METHODS: Seven databases were systematically searched, spanning the interval from 2016 to August 2023. Randomized controlled trials (RCTS) comparing dorzagliatin with placebo for the treatment of T2DM were applicable for containing this study. The relevant data were extracted, and a meta-analysis was implemented using RevMan 5.4 software. RESULTS: A total of 3 studies involving 1332 patients were included. We use glycated hemoglobin (HbA1c) levels as the major indicator of efficacy, FBG, 2h postprandial blood glucose, Homa-ß and Homa-IR to be Secondary outcome measures. Compared with placebo group, dorzagliatin significantly reduced blood glucose levels as well as enhanced insulin resistance. In terms of safety, no serious adverse events occurred. However, lipid-related indicators, especially triglycerides levels, and the incidence of hypoglycemia were higher in patients in the dorzagliatin group compared with those in the control group, but the increase from baseline was mild. CONCLUSIONS: Dorzagliatin exerted favorable effects in hypoglycemic control, effectively reduced the HbA1c, FBG, and 2h postprandial blood glucose levels in T2DM patients, stimulated the secretion of insulin during the initial phase, and exerted a consistent hypoglycemic effect. However, the incidence of adverse events such as elevated blood lipids and cardiovascular risk warrants further investigations through long-term clinical trials.


Subject(s)
Diabetes Mellitus, Type 2 , Glucokinase , Pyrazoles , Humans , Glycated Hemoglobin , Blood Glucose/analysis , Randomized Controlled Trials as Topic , Diabetes Mellitus, Type 2/complications , Hypoglycemic Agents/adverse effects
18.
19.
Int J Mol Sci ; 25(1)2024 Jan 01.
Article in English | MEDLINE | ID: mdl-38203742

ABSTRACT

Achieving glycemic control and sustaining functional pancreatic ß-cell activity remains an unmet medical need in the treatment of type 2 diabetes mellitus (T2DM). Glucokinase activators (GKAs) constitute a class of anti-diabetic drugs designed to regulate blood sugar levels and enhance ß-cell function in patients with diabetes. A significant progression in GKA development is underway to address the limitations of earlier generations. Dorzagliatin, a dual-acting GKA, targets both the liver and pancreas and has successfully completed two phase III trials, demonstrating favorable results in diabetes treatment. The hepato-selective GKA, TTP399, emerges as a strong contender, displaying clinically noteworthy outcomes with minimal adverse effects. This paper seeks to review the current literature, delve into the mechanisms of action of these new-generation GKAs, and assess their efficacy and safety in treating T2DM based on published preclinical studies and recent clinical trials.


Subject(s)
Diabetes Mellitus, Type 2 , Drug-Related Side Effects and Adverse Reactions , Humans , Diabetes Mellitus, Type 2/drug therapy , Glucokinase , Pancreas , Glycemic Control
20.
J Biomater Sci Polym Ed ; 35(4): 535-558, 2024 04.
Article in English | MEDLINE | ID: mdl-38234041

ABSTRACT

Bio-synthesized silver nanoparticles (AgNPs) were successfully obtained using the leaf extract from Ventilago maderaspatana. Extensive analysis was conducted to evaluate the physical and chemical characteristics of the bioderived AgNPs. XRD analysis confirmed their cubic structure, and revealed a well-defined size distribution with average crystallite size of 11.7 nm. FE-SEM and TEM images visually supported the observed size range. The presence of plant-mediated phytochemicals on the surface of AgNPs was confirmed through DLS, FTIR, and TGA/DTA studies. To assess their antidiabetic potential, rats were induced with streptozotocin, resulting in elevated levels of biochemical parameters associated with diabetes. Conversely, serum insulin levels (2.50 ± 0.55) and glucokinase activity (64.50 ± 8.66) decreased. However, treatment with AgNPs demonstrated a dose-dependent reduction in blood glucose, total protein, albumin, and HbA1c levels, effectively restoring them to normal ranges. Moreover, the treatment significantly increased insulin levels (7.55 ± 0.63) and glucokinase activity (121.50 ± 4.60), indicating the antidiabetic potential of V. maderaspatana-mediated AgNPs. Notably, the exitance of phytochemicals, like flavonoids and phenols, on the surface of AgNPs facilitated their ability to neutralize reactive oxygen species (ROS) through electron donation. This property enhanced their overall antidiabetic efficiency.


Subject(s)
Diabetes Mellitus , Insulins , Metal Nanoparticles , Rats , Animals , Antioxidants/pharmacology , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Metal Nanoparticles/chemistry , Silver/chemistry , Streptozocin , Glucokinase
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