Design and synthesis of novel pyrimido[5,4-d]pyrimidine derivatives as GPR119 agonist for treatment of type 2 diabetes

Metabolomics in Diabetic Retinopathy: From Potential Biomarkers to Molecular Basis of Oxidative Stress

Diabetic retinopathy (DR), the leading cause of blindness in working-age adults, is one of the most common complications of diabetes mellitus (DM) featured by metabolic disorders. With the global prevalence of diabetes, the incidence of DR is expected to increase. Prompt detection and the targeting of anti-oxidative stress intervention could effectively reduce visual impairment caused by DR. However, the diagnosis and treatment of DR is often delayed due to the absence of obvious signs of retina imaging. Research progress supports that metabolomics is a powerful tool to discover potential diagnostic biomarkers and therapeutic targets for the causes of oxidative stress through profiling metabolites in diseases, which provides great opportunities for DR with metabolic heterogeneity. Thus, this review summarizes the latest advances in metabolomics in DR, as well as potential diagnostic biomarkers, and predicts molecular targets through the integration of genome-wide association studies (GWAS) with metabolomics. Metabolomics provides potential biomarkers, molecular targets and therapeutic strategies for controlling the progress of DR, especially the interventions at early stages and precise treatments based on individual patient variations.

A Review on Fused Pyrimidine Systems as EGFR Inhibitors and Their Structure–Activity Relationship

Epidermal growth factor receptor (EGFR) belongs to the family of tyrosine kinase that is activated when a specific ligand binds to it. The EGFR plays a vital role in the cellular proliferation process, differentiation, and apoptosis. In the case of cancer, EGFR undergoes uncontrolled auto-phosphorylation that results in increased cellular proliferation and decreased apoptosis, causing cancer promotion. From the literature, it shows that pyrimidine is one of the most commonly studied heterocycles for its antiproliferative activity against EGFR inhibition. The authors have collated some interesting results in the heterocycle-fused pyrimidines that have been studied using different cell lines (sensitive and mutational) and in animal models to determine their activity and potency. It is quite clear that the fused systems are highly effective in inhibiting EGFR activity in cancer cells. Therefore, the structure–activity relationship (SAR) comes into play in determining the nature of the heterocycle and the substituents that are responsible for the increased activity and toxicity. Understanding the SAR of heterocycle-fused pyrimidines will help in getting a better overview of the molecules concerning their activity and potency profile as future EGFR inhibitors.

Diagnostic value of microbiome biomarkers of the periodonite microbiome in patients with the association of chronic periodontitis and diabetes mellitus type 2

The place of high-tech methods of molecular biology in clinical laboratory diagnostics of various diseases and the development of a system of biomarkers as an important component of diagnostic research is currently attracting the closest attention of the scientific community. In this paper, an attempt is made to use high-tech metagenomic analysis to solve problems that arise due to the high frequency of association of periodontal diseases with systemic pathology, in particular, with type 2 diabetes mellitus. The aim of the study was to determine the taxonomic and metabolic features of the microbiome of periodontal tissues in periodontal diseases associated with type 2 diabetes mellitus, as a model of the ratio of local and systemic effects of periodontal pathogenic bacteria. The study included 16S shotgun sequencing of bacterial DNA as part of biological material from periodontal pockets/dentoalveolar furrows of 46 people - 15 patients with chronic periodontitis associated with type 2 diabetes mellitus, 15 patients with chronic periodontitis unrelated to systemic pathology, as well as 16 healthy people in the control group, followed by bioinformatic processing of the data obtained. The obtained data allowed us to establish the taxonomic features of the periodontal microbiome in the association of chronic periodontitis with type 2 diabetes mellitus, which included the predominance of representatives of the families Prevotellaceae and Spirochaetaceae in its composition. The features of metabolic processes in periodontal tissues with the participation of the microbiome were also revealed, which consisted in an increase in the exchange of cysteine and methionine against the background of a decrease in the metabolism of pyrimidine, methane, sphingolipids, and the synthesis of fatty acids, which are of diagnostic value in assessing the condition of patients with type 2 diabetes mellitus.

GPR119 agonists: Novel therapeutic agents for type 2 diabetes mellitus

Diabetes mellitus type 2 (T2D) is a group of genetically heterogeneous metabolic disorders whose frequency has gradually risen worldwide. Diabetes mellitus Type 2 (T2D) has started to achieve a pandemic level, and it is estimated that within the next decade, cases of diabetes might get double due to increase in aging population. Diabetes is rightly called the 'silent killer' because it has emerged to be one of the major causes, leading to renal failure, loss of vision; besides cardiac arrest in India. Thus, a clinical requirement for the oral drug molecules monitoring glucose homeostasis appears to be unmet. GPR119 agonist, a family of G-protein coupled receptors, usually noticed in β-cells of pancreatic as well as intestinal L cells, drew considerable interest for type 2 diabetes mellitus (T2D). GPR119 monitors physiological mechanisms that enhance homeostasis of glucose, such as glucose-like peptide-1, gastrointestinal incretin hormone levels, pancreatic beta cell-dependent insulin secretion and glucose-dependent insulinotropic peptide (GIP). In this manuscript, we have reviewed the work done in the last five years (2015-2020) which gives an approach to design, synthesize, evaluate and study the structural activity relationship of novel GPR119 agonist-based lead compounds. Our article would help the researchers and guide their endeavours in the direction of strategy and development of innovative, effective GPR119 agonist-based compounds for the management of diabetes mellitus type 2.

Metabolites in the association between early-life famine exposure and type 2 diabetes in adulthood over a 5-year follow-up period

INTRODUCTION

Exposure to malnutrition in early life has been found to significantly elevate type 2 diabetes risk in adulthood. However, the changes in metabolites resulting from malnutrition in early life have not been studied. The aim of this study was to identify metabolites with levels associated with type 2 diabetes resulting from exposure to China's Great Famine (1959-1962).

RESEARCH DESIGN AND METHODS

Participants were from SPECT-China 2014 and SPECT-China2 2019, two cross-sectional studies performed at the same site. In total, 2171 subjects participated in SPECT-China and SPECT-China2 simultaneously. The sample size of fetal-exposed (1959-1962) versus non-exposed (1963-1974) individuals was 82 vs 79 in 2014 and 97 vs 94 in 2019. Metabolomic profiling was performed between famine-exposed and non-exposed groups.

RESULTS

Among the different famine exposure groups, the fetal-exposed group (1959-1962) had the greatest incidence rate (12.5%), with an OR of 2.11 (95% CI 1.01 to 4.44), compared with the non-exposed group (1963-1974). Moreover, compared with those in the non-exposed group (1963-1974), four metabolites (indole-3-carbinol (I3C), phosphatidylcholine (PC) (22:6(4Z,7Z,10Z,13Z,16Z,19Z)/16:1(9Z)), pyrimidine, and PC(16:1(9Z)/22:5(4Z,7Z,10Z,13Z,16Z))) showed significantly lower relative intensities in the famine and diabetes groups both in 2014 and 2019. Pyrimidine significantly mediated the association of famine exposure with diabetes, and I3C marginally mediated this association.

CONCLUSIONS

Famine exposure in the fetal period could increase type 2 diabetes risk in adults, even those in their 60s. I3C and pyrimidine are potential mediators of the effects of famine exposure on diabetes development.

SIS3, a good candidate for the reverse of type 2 diabetes mellitus in mice

TGF-β signaling plays an extremely important role in the occurrence and development of type 2 diabetes mellitus (T2DM), and the blockade of TGF-β/Smad3 pathway protests against the high-fat diet-induced obesity and diabetes. As a specific small molecule inhibitor of Smad3 protein, the biological activities of compound SIS3 were evaluated by high-fat diet-induced T2DM model mice. In vivo results indicated that SIS3 can not only significantly reduce the body weight, fat mass, and fasting blood glucose in high-fat diet-induced T2DM model mice, but also improve insulin sensitivity and oral glucose tolerance of high-fat diet-induced T2DM model mice after the injection of SIS3 with 5 mg/kg for 45 days.

Advances in the chemical and biological diversity of heterocyclic systems incorporating pyrimido[1,6-a]pyrimidine and pyrimido[1,6-c]pyrimidine scaffolds

Heterocycles incorporating a pyrimidopyrimidine scaffold have aroused great interest from researchers in the field of medical chemistry because of their privileged biological activities; they are used as anti-bacterial, antiviral, anti-tumor, anti-allergic, antihypertensive, anticancer, and hepatoprotective agents. Therefore, the present study aims to investigate the chemistry of heterocycles incorporating pyrimido[1,6-a]pyrimidine and pyrimido[1,6-c]pyrimidine skeletons and their biological characteristics. The main sections discuss (1) the synthetic routes to obtain substituted pyrimidopyrimidines, pyrimido[1,6-a]pyrimidin-diones, pyrimidoquinazolines, tricyclic, tetracyclic, and binary systems; (2) the reactivity of the substituents attached to the pyrimidopyrimidine skeleton, including thione and amide groups, nucleophilic substitutions, condensations, ring transformations, and coordination chemistry; (3) compounds of this class of heterocycles containing a significant characteristic scaffold and possessing a wide range of biological characteristics.

Anti-diabetic drugs recent approaches and advancements

Diabetes is one of the major diseases worldwide and is the third leading cause of death in the United States. Anti-diabetic drugs are used in the treatment of diabetes mellitus to control glucose levels in the blood. Most of the drugs are administered orally, except for a few of them, such as insulin, exenatide, and pramlintide. In this review, we are going to discuss seven major types of anti-diabetic drugs: Peroxisome proliferator-activated receptor (PPAR) agonist, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase inhibitors, α-glucosidase inhibitors, dipeptidyl peptidase IV (DPP-4) inhibitors, G protein-coupled receptor (GPCR) agonists and sodium-glucose co-transporter (SGLT) inhibitors. Here, we are also discussing some of the recently reported anti-diabetic agents with its multi-target pharmacological actions. This review summarises recent approaches and advancement in anti-diabetes treatment concerning characteristics, structure-activity relationships, functional mechanisms, expression regulation, and applications in medicine.

Optimisation of novel 4, 8-disubstituted dihydropyrimido[5,4-b][1,4]oxazine derivatives as potent GPR 119 agonists

GPR119 is a promising target for discovery of anti-type 2 diabetes mellitus agents. We described the optimisation of a novel series of pyrimido[5,4-b][1,4]oxazine derivatives as GPR119 agonists. Most designed compounds exhibited good agonistic activities. Among them, compound 10 and 15 demonstrated the potent EC₅₀ values (13 and 12 nM, respectively) and strong inherent activities. Moreover, significant hypoglycaemic effect of compound 15 was observed by reducing the blood glucose AUC_0-2h at the dose of 30 mg/kg, which is stronger than Vildagliptin (23.4% reduction vs. 17.9% reduction).

Design and synthesis of tetrahydropyridopyrimidine derivatives as dual GPR119 and DPP-4 modulators

Based on the approach of merged pharmacophores of GPR119 agonists and DPP-4 inhibitors, a series of tetrahydropyridopyrimidine compounds were designed as dual GPR119 and DPP-4 modulators with hypoglycemic activity. Seven fragments extracted from DPP-4 inhibitors were hybridized with the scaffold of tetrahydropyridopyrimidine. Among them, compound 51 displayed most potent GPR119 agonistic activity (EC₅₀ = 8.7 nM) and good inhibition rate of 74.5% against DPP-4 at 10 μM. Furthermore, the blood glucose AUC_0-2h of 51 was reduced to 19.5% in the oral glucose tolerance test (oGTT) at the dose of 30 mg/kg in C57BL/6N mice, which was more potent than that of vildagliptin (16.4%) at the same dose. The docking study of compound 51 with DPP-4 indicated GPR119 agonists could inhibit DPP-4 to serve as dual GPR119 and DPP-4 modulators.

Bicyclic 6 + 6 systems: the chemistry of pyrimido[4,5-d]pyrimidines and pyrimido[5,4-d]pyrimidines

The present study provides an overview of the chemistry and biological significance of pyrimido[4,5-d]pyrimidine and pyrimido[5,4-d]pyrimidine analogs as types of bicyclic [6 + 6] systems. The main sections include: (1) synthesis methods; (2) the reactivities of the substituents linked to the ring carbon and nitrogen atoms; and (3) biological applications. A discussion demonstrating the proposed mechanisms of unexpected synthetic routes is intended. The aim of this study is to discuss the synthetic significance of the titled compounds and to establish the biological characteristics of this class of compounds as studied to date, where the compounds have been applied on a large scale in the medical and pharmaceutical fields. This survey will help researchers in the fields of synthetic organic and medicinal chemistry to undertake and improve new approaches for the construction of new standard biological components.

Synthesis and evaluation of novel fused pyrimidine derivatives as GPR119 agonists

A novel series of fused pyrimidine derivatives were designed, synthesized and evaluated as GPR119 agonists. Among them, cyclohexene fused compounds (tetrahydroquinazolines) showed greater GPR119 agonistic activities than did dihydrocyclopentapyrimidine and tetrahydropyridopyrimidine scaffolds. Analogues (16, 19, 26, 28, 42) bearing endo-N-Boc-nortropane amine and fluoro-substituted aniline exhibited better EC₅₀ values (0.27-1.2 μM) though they appeared to be partial agonists.