A comprehensive review on glucokinase activators: Promising agents for the treatment of Type 2 diabetes

Antidiabetic constituents of Kaempferiae rhizoma: Previously undescribed O-linked diarylheptanoid dimers promoting GLP-1 secretion via PKA-CREB pathway

Glucagon-like peptide-1 (GLP-1) is a fascinating target for the treatment of diabetes to avoid hypoglycemia. Kaempferiae Rhizoma (KR), the dried rhizomes of Kaempferia galanga, is a famous pungent medicine used for activating Qi, warming interior, removing digestion and relieving pain in China. In order to characterize the antidiabetic effects of KR, 21 previously undescribed O-linked diarylheptanoid dimers, kaemgalangins A1-A4 (1-4), B1-B13 (5-17) and C1-C4 (18-21), were isolated from the ethyl acetate fraction. Their structures were determined by extensive spectroscopic analyses, quantum computation and chemical methods. All compounds were tested for their GLP-1 stimulating effects on NCI-H716 cells, most of which showed obvious activity representing a new type of antidiabetic constituents. Especially, compounds 1, 2 and 16 showed spectacular GLP-1 stimulation with promoting rates of 146.6 ± 31.1 %, 159.0 ± 16.6 % and 142.9 ± 2.7 %, more potent than the positive control. Mechanism study manifested that kaemgalangin A1 (1) promoted GLP-1 secretion through up-regulating the mRNA expression of Gcg and Pc1/3, and the phosphorylation of PKA and CREB, but independent on TGR5 and GPR119 receptors. Furthermore, network pharmacology analysis suggested that the GLP-1 secretion induced by 1 was closely related to MAPK and PI3K-Akt signaling pathways. This investigation first revealed that KR was rich in diarylheptanoid dimers with GLP-1 promoting effects, which provides scientific basis for the antidiabetic application of K. galanga.

Aldolase-regulated G3BP1/2+ condensates control insulin mRNA storage in beta cells

Upregulation of insulin mRNA translation upon hyperglycemia in pancreatic islet β-cells involves several RNA-binding proteins. Here, we found that G3BP1, a stress granule marker downregulated in islets of subjects with type 2 diabetes, binds to insulin mRNA in glucose concentration-dependent manner. We show in mouse insulinoma MIN6-K8 cells exposed to fasting glucose levels that G3BP1 and its paralog G3BP2 colocalize to cytosolic condensates with eIF3b, phospho-AMPKαThr172 and Ins1/2 mRNA. Glucose stimulation dissolves G3BP1+/2+ condensates with cytosolic redistribution of their components. The aldolase inhibitor aldometanib prevents the glucose- and pyruvate-induced dissolution of G3BP1+/2+ condensates, increases phospho-AMPKαThr172 levels and reduces those of phospho-mTORSer2448. G3BP1 or G3BP2 depletion precludes condensate assembly. KO of G3BP1 decreases Ins1/2 mRNA abundance and translation as well as proinsulin levels, and impaires glucose-stimulated insulin secretion. Further, other insulin secretagogues such as exendin-4 and palmitate, but not high KCl, prompts the dissolution of G3BP1+/2+ condensates. G3BP1+/2+/Ins mRNA+ condensates are also found in primary mouse and human β-cells. Hence, G3BP1+/2+ condensates represent a conserved glycolysis/aldolase-regulated compartment for the physiological storage and protection of insulin mRNA in resting β-cells.

Network Pharmacology-Based Elucidation of the Hypoglycemic Mechanism of Grifola frondosa GF5000 Polysaccharides via GCK modulation in Diabetic Rats

BACKGROUND/OBJECTIVES

Our lab has previously reported that Grifola frondosa (maitake mushroom) GF5000 has antidiabetic potential owing to its ability to improve insulin resistance. This study aimed to gain insight into the system-level hypoglycemic mechanisms of GF5000 using transcriptomics, proteomics, and network pharmacology. This study provides new insights into the hypoglycemic mechanisms of GF5000, identifying key molecular targets involved in mitigating insulin resistance in T2DM.

METHODS

Liver protein and gene expression in normal control (NC), diabetic control (DC), and GF5000-treated (GF5000) rats were analyzed via iTRAQ and RNA-seq. The relationships between differentially expressed genes (DEGs), differentially expressed proteins (DEPs), and type 2 diabetes (T2DM) disease targets were studied using Metascape and the Cytoscape GeneMANIA plug-in.

RESULTS

One hundred and fifty-two DEGs and sixty-two DEPs were identified; twenty DEGs/DEPs exhibited the same trend in mRNA and protein expression levels when comparing the GF5000 vs. DC groups. The Metascape analysis revealed that the T2DM disease targets included four DEGs-Gck, Scd, Abcb4, and Cyp3a9-and two DEPs-glucokinase and acetyl-CoA carboxylase 2. A Cytoscape-GeneMANIA analysis of thirteen DEGs/DEPs related to T2DM showed that Apoa1/Apolipoprotein A-I, Gckr/glucokinase regulatory protein, and Gck/glucokinase had the highest connectivity and centrality in the topological network. The qPCR results confirmed that GF5000 increased the mRNA expression of GCK in GCK-knockdown HepG2 cells.

CONCLUSIONS

These results provide theoretical evidence for the use of GF5000 as a potential active nutritional ingredient for the prevention and treatment of T2DM. Our findings suggest that GF5000 targets multiple pathways implicated in T2DM, offering a multi-faceted approach to disease management and prevention.

Is it feasible to treat polycystic ovarian syndrome with or without insulin resistance using glucokinase activators as novel hypoglycaemic medications? A protocol for a systematic review and meta-analysis

INTRODUCTION

A variety of hypoglycaemic drugs are used to treat polycystic ovarian syndrome (PCOS), but their efficacy remains insufficient. Glucokinase activators (GKAs) are a unique class of hypoglycaemic medications with emerging potential, notably in significantly reducing insulin resistance (IR). Nevertheless, the efficacy of GKAs in treating PCOS, particularly in the absence or presence of IR, remains uncertain. The meta-analysis protocol aims to address this knowledge gap, furnish evidence-based data to support potential revisions in PCOS treatment guidelines and promote the utilisation of GKAs in clinical settings.

METHODS AND ANALYSIS

A comprehensive search will be conducted across the Cochrane Central Register of Controlled Trials, PubMed, Web of Science, Embase, Medline, Scopus, CNKI, Wanfang and VIP databases to identify randomised controlled trials investigating the use of GKAs in the treatment of PCOS, irrespective of the presence of IR. The search will encompass all available studies without language restrictions and cover the period from the inception of each database to 10 April 2024. Disputes will be resolved by talking with a third expert following the screening of articles and data extraction by two reviewers. The primary outcomes of interest encompass changes in anthropometric parameters, menstrual frequency, sex hormone levels, and glucose metabolism, while secondary objectives include lipid metabolism and adverse events. The methodological quality of each study will be assessed using Version 2 of the Cochrane Collaboration tool for assessing Risk of Bias (RoB 2.0), and the Grade of Recommendations, Assessment, Development and Evaluation (GRADE) technique will be used to assess the quality of evidence and degree of recommendation. The study duration of this study will be from 5 April 2024 to 10 April 2025.

ETHICS AND DISSEMINATION

Since this study just analyses data that are readily available to the public and does not directly involve patient participation, ethical approval is not necessary. The findings will be made public by being published in a medical journal that is subject to peer review.

PROSPERO REGISTRATION NUMBER

CRD42024535633.

Glucokinase activators and imeglimin: new weaponry in the armamentarium against type 2 diabetes

The prevalence of type 2 diabetes (T2D) is increasing relentlessly all over the world, in parallel with a similar increase in obesity, and is striking ever younger patients. Only a minority of patients with T2D attain glycemic targets, indicating a clear need for novel antidiabetic drugs that not only control glycemia but also halt or slow the progressive loss of β-cells. Two entirely novel classes of antidiabetic agents-glucokinase activators and imeglimin-have recently been approved and will be the subject of this review.Allosteric activators of glucokinase, an enzyme stimulating insulin secretion in β-cells and suppressing hepatic glucose production, are oral low-molecular-weight drugs. One of these, dorzagliatin, is approved in China for use in adult patients with T2D, either as monotherapy or as an add-on to metformin. It remains to be seen whether the drug will produce sustained antidiabetic effects over many years and whether the side effects that led to the discontinuation of early drug candidates will limit the usefulness of dorzagliatin.Imeglimin-which shares structural similarities with metformin-targets mitochondrial dysfunction and was approved in Japan against T2D. In preclinical studies, the drug has also shown promising β-cell protective and preservative effects that may translate into disease-modifying effects.Hopefully, these two newcomers will contribute to filling the great medical need for new treatment modalities, preferably with disease-modifying potential. It remains to be seen where they will fit in contemporary treatment algorithms, which combinations of drugs are effective and which should be avoided. Time will tell to what extent these new antidiabetic agents will add value to the current treatment options against T2D in terms of sustained antidiabetic effect, acceptable safety, utility in combination therapy, and impact on hard end-points such as cardiovascular disease.

Targeting Protein Kinases to Protect Beta-Cell Function and Survival in Diabetes

The prevalence of diabetes is increasing worldwide. Massive death of pancreatic beta-cells causes type 1 diabetes. Progressive loss of beta-cell function and mass characterizes type 2 diabetes. To date, none of the available antidiabetic drugs promotes the maintenance of a functional mass of endogenous beta-cells, revealing an unmet medical need. Dysfunction and apoptotic death of beta-cells occur, in particular, through the activation of intracellular protein kinases. In recent years, protein kinases have become highly studied targets of the pharmaceutical industry for drug development. A number of drugs that inhibit protein kinases have been approved for the treatment of cancers. The question of whether safe drugs that inhibit protein kinase activity can be developed and used to protect the function and survival of beta-cells in diabetes is still unresolved. This review presents arguments suggesting that several protein kinases in beta-cells may represent targets of interest for the development of drugs to treat diabetes.

Clinical investigation of glucokinase activators for the restoration of glucose homeostasis in diabetes

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.

Molecular docking, pharmacokinetic prediction and molecular dynamics simulations of tankyrase inhibitor compounds with the protein glucokinase, induced in the development of diabetes

GCK is a protein that plays a crucial role in the sensing and regulation of glucose homeostasis, which associates it with disorders of carbohydrate metabolism and the development of several pathologies, including gestational diabetes. This makes GCK an important therapeutic target that has aroused the interest of researchers to discover GKA that are simultaneously effective in the long term and free of side effects. TNKS is a protein that interacts directly with GCK; recent studies have shown that it inhibits GCK action, which affects glucose detection and insulin secretion. This justifies our choice of TNKS inhibitors as ligands to test their effects on the GCK-TNKS complex. For this purpose, we investigated the interaction of the GCK-TNKS complex with 13 compounds (TNKS inhibitors and their analogues) using the molecular docking approach as a first step, after which the compounds that generated the best affinity scores were evaluated for drug similarity and pharmacokinetic properties. Subsequently, we selected the six compounds that generated high affinity and that were in accordance with the parameters of the drug rules as well as pharmacokinetic properties to ensure a molecular dynamics study. The results allowed us to favor the two compounds (XAV939 and IWR-1), knowing that even the tested compounds (TNKS 22, (2215914) and (46824343)) produced good results that can also be exploited. These results are therefore interesting and encouraging, and they can be exploited experimentally to discover a treatment for diabetes, including gestational diabetes.Communicated by Ramaswamy H. Sarma.

Efficacy and safety of dorzagliatin, a novel glucokinase activators, in the treatment of T2DM: A meta-analysis of randomized controlled trials

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-β 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.

Glucokinase Inhibition: A Novel Treatment for Diabetes?

Chronic hyperglycemia increases pancreatic β-cell metabolic activity, contributing to glucotoxicity-induced β-cell failure and loss of functional β-cell mass, potentially in multiple forms of diabetes. In this perspective we discuss the novel paradoxical and counterintuitive concept of inhibiting glycolysis, particularly by targeted inhibition of glucokinase, the first enzyme in glycolysis, as an approach to maintaining glucose sensing and preserving functional β-cell mass, thereby improving insulin secretion, in the treatment of diabetes.

Transporter-Mediated Drug Delivery

Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.

Efficacy and safety of novel dual glucokinase activator dorzagliatin in type-2 diabetes A meta-analysis

BACKGROUND & AIMS

Glucokinase has a critical role in regulating glucose homeostasis in humans, and has been a target for diabetes drug development since 1990s. Dorzagliatin is a novel allosteric dual glucokinase activator targeting both pancreatic and hepatic glucokinase. No meta-analysis has analysed the efficacy and safety of dorzagliatin in type-2 diabetes (T2DM). We undertook this meta-analysis to address this knowledge-gap.

METHODS

Electronic databases were searched for RCTs involving T2DM patients receiving dorzagliatin in intervention arm, and placebo/active comparator in control arm. Primary outcome was to evaluate changes in HbA1c. Secondary outcomes were to evaluate alterations in blood glucose parameters, lipids, insulin-resistance and adverse events.

RESULTS

From initially screened 17 articles, data from 3 RCTs (1333 patients) was analysed. Over 12-24 weeks use, dorzagliatin had significantly higher lowering of HbA1c [MD -0.66% (95%CI: -0.74 to -0.59); P < 0.01; I² = 99%], fasting glucose [MD -32.03 mg/dl (95%CI: 45.12 to -18.94); P < 0.01; I² = 100%], 2-h post-prandial glucose [MD -43.49 mg/dl (95%CI: -46.26 to -40.72); P < 0.01; I² = 90%] along with greater number of patients achieving HbA1c<7% [OR 6.01 (95% CI: 2.50-14.46); P < 0.01; I² = 83%], as compared to placebo. Dorzagliatin was associated with significant elevation of triglycerides [MD 0.43 mmol/L (95%CI:0.30-0.56); P < 0.01; I² = 0%], greater occurrence of hyperlipidaemia [RR 1.52 (95% CI:1.05-2.18); P = 0.03; I² = 0%], and increase in body-weight [MD 0.40 kg (95%CI:0.06-0.75); P = 0.03; I² = 0%], compared to placebo. The occurrence of total-adverse-events [RR 1.43 (95%CI:1.11-1.83); P < 0.01; I² = 0%] but not severe adverse-events [RR 0.92 (95%CI:0.54-1.57); P = 0.76; I² = 0%] was significantly higher with dorzagliatin.

CONCLUSION

Dorzagliatin has good glycaemic efficacy and well tolerated over 6-months use. Mild increase in body-weight, serum triglycerides and overall adverse events remain issues of concern warranting further evaluation in longer clinical trials with active controls.

Efficacy and safety of dorzagliatin for type 2 diabetes mellitus: A meta-analysis and trial sequential analysis

Objective

To evaluate the efficacy and safety of dorzagliatin in the treatment of type 2 diabetes mellitus (T2DM) by using meta-analysis and trial sequential analysis (TSA).

Method

Search for clinical trials of dorzagliatin for T2DM in eight databases, with a time limit of build to July 2022. The included studies that met the requirements were carried out for meta-analysis and TSA.

Results

In terms of efficacy endpoints, meta-analysis showed that dorzagliatin decreased glycated hemoglobin A1c(HbA1c) [mean difference (MD) -0.65%, 95% confidence interval (CI) -0.76 ~ -0.54, P < 0.00001], fasting plasma glucose (FPG) (MD -9.22 mg/dL, 95% CI -9.99 ~ -8.44, P < 0.00001), 2 h postprandial glucose (2h-PPG) (MD -48.70 mg/dL, 95% CI -55.45 ~ -41.96, P < 0.00001), homeostasis model assessment 2 of insulin resistance (HOMA2-IR) (MD -0.07, 95% CI -0.14 ~ -0.01, P = 0.03) and increased homeostasis model assessment 2 of ß-cells function (HOMA2-β) (MD 2.69, 95% CI 1.06 ~ 4.31, P = 0.001) compared with placebo. And TSA revealed that the benefits observed for the current information set were conclusive, except for HOMA2-IR. In comparison with placebo, dorzagliatin increased triglyceride(TG) (MD 0.43 mmol/L, 95% CI 0.30 ~ 0.56, P < 0.00001), total cholesterol (TC) (MD 0.13 mmol/L, 95% CI 0.05 ~ 0.21, P = 0.001), body weight (MD 0.38 kg, 95% CI 0.12-0.63, P = 0.004) and body mass index (BMI) (MD 0.14 kg/m², 95% CI 0.05-0.24, P = 0.003), while low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were comparable. And TSA demonstrated that TG, TC, body weight, and BMI were conclusive. In terms of safety endpoints, dorzagliatin increased total adverse events (AEs) [risk ratio (RR) 1.56, 95% CI 1.06 ~ 2.30, P = 0.03], while serious AEs, hyperlipidemia, and hypoglycaemia were all comparable. And TSA indicated that the results need to be confirmed by additional studies. Harbord regression showed no publication bias.

Conclusion

Dorzagliatin was effective in lowering glycemia, reducing insulin resistance and improving islet ß-cells function without affecting blood pressure, LDL-C, and HDL-C. Although dorzagliatin caused a mild increase in TG and TC, it did not increase the incidence of hyperlipidemia, and the small increases in body weight and BMI were not clinically significant enough. In terms of safety, the total AEs caused by dorzagliatin may be a cumulative effect of single AEs, with no drug-related adverse event being reported at a higher incidence than placebo alone. Dorzagliatin's serious AEs, hyperlipidemia, and hypoglycemia are comparable to that of placebo, and dorzagliatin has a good safety profile.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371802 identifier: CRD42022371802.

Genetic and Pharmacological Inhibition of GCN2 Ameliorates Hyperglycemia and Insulin Resistance in Type 2 Diabetic Mice

It is well recognized that there is a strong and complex association between nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D). We previously demonstrated that genetic knockout or pharmacological inhibition of general control nondepressible kinase 2 (GCN2), a well-known amino acid sensor, alleviated hepatic steatosis and insulin resistance in obese mice. However, whether GCN2 affects the development of T2D remains unclear. After a high-fat diet (HFD) plus low-dose streptozotocin (STZ) treatments, Gcn2−/− mice developed less hyperglycemia, insulin resistance, hepatic steatosis, and oxidative stress than wild-type (WT) mice. Inhibition of GCN2 by intraperitoneal injection of 3 mg/kg GCN2iB (a specific inhibitor of GCN2) every other day for 6 weeks also ameliorated hyperglycemia, insulin resistance, hepatic steatosis, and oxidative stress in HFD/STZ- and leptin receptor deletion (db/db)-induced T2D mice. Moreover, depletion of hepatic GCN2 in db/db mice by tail vein injection of an AAV8-shGcn2 vector resulted in similar improvement in those metabolic disorders. The protective mechanism of GCN2 inhibition in T2D mice was associated with regulation of the glucose metabolic pathway, repression of lipogenesis genes, and activation of the Nrf2 pathway. Together, our data provide evidence that strategies to inhibit hepatic GCN2 activity may be novel approaches for T2D therapy.

Disruptions in hepatic glucose metabolism are involved in the diminished efficacy after chronic treatment with glucokinase activator

Glucokinase activators are regarded as potent candidates for diabetes treatment, however, in clinical studies on patients with type 2 diabetes, a diminishing efficacy was observed after chronic treatment with them. The mechanism of this reduction has not been elucidated, and whether it is a class effect of glucokinase activators remains inconclusive. Here, we firstly identified a diabetic animal model that shows the diminished efficacy after long-term treatment with MK-0941, a glucokinase activator that exhibited diminished efficacy in a clinical study, and we analyzed the mechanism underlying its diminished efficacy. In addition, we evaluated the long-term efficacy of another glucokinase activator, TMG-123. Goto-Kakizaki rats were treated with MK-0941 and TMG-123 for 24 weeks. The results showed that glycated hemoglobin A1C levels and plasma glucose levels decreased transiently but increased over time with the continuation of treatment in the MK-0941-treated group, while decreased continuously in the TMG-123-treated group. Only in the TMG-123-treated group, higher plasma insulin levels were shown at the later stage of the treatment period. For the mechanism analysis, we conducted a hepatic enzyme assay and liver perfusion study in Goto-Kakizaki rats after chronic treatment with MK-0941 and TMG-123, and revealed that, only in the MK-0941-treated group, the activity of glucose-6-phosphatase was increased, and hepatic glucose utilization was decreased compared to the non-treated group. These data indicate that disruptions in hepatic glucose metabolism are involved in the diminished efficacy of glucokinase activators.

Advances in computer-aided drug design for type 2 diabetes

INTRODUCTION

The number of diabetic patients is increasing, posing a heavy social and economic burden worldwide. Traditional drug development technology is time-consuming and costly, and the emergence of computer-aided drug design (CADD) has changed this situation. This study reviews the applications of CADD in diabetic drug designing.

AREAS COVERED

In this article, the authors focus on the advance in CADD in diabetic drug design by elaborating the discovery, including peroxisome proliferator-activated receptor (PPAR), G protein-coupled receptor 40 (GPR40), dipeptidyl peptidase-IV (DDP-IV), protein tyrosine phosphatase 1B (PTP1B), sodium-dependent glucose transporter 2 (SGLT-2), and glucokinase (GK). Some drug discovery of these targets is related to CADD strategies.

EXPERT OPINION

There is no doubt that CADD has contributed to the discovery of novel anti-diabetic agents. However, there are still many limitations and challenges, such as lack of co-crystal complex, dynamic simulations, water, and metal ion treatment. In the near future, artificial intelligence (AI) may be a promising strategy to accelerate drug discovery and reduce costs by identifying candidates. Moreover, AlphaFold, a deep learning model that predicts the 3D structure of proteins, represents a considerable advancement in the structural prediction of proteins, especially in the absence of homologous templates for protein structures.