Recent Updates on Free Fatty Acid Receptor 1 (GPR-40) Agonists for the Treatment of Type 2 Diabetes Mellitus

Efficacy of Huanglian Jiedu Decoction for Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disorder, and there is an increasing interest in the potential benefits of traditional Chinese medicine, such as Huanglian Jiedu decoction (HJD), for its management. This meta-analysis aimed to determine the efficacy and safety of HJD in the treatment of T2DM.

METHODS

A systematic review was conducted across six databases including PubMed, Embase, Cochrane, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang, from their inception to August 24, 2023. We focused on randomized controlled trials (RCTs) that evaluated HJD as both a monotherapy and in combination treatments for T2DM patients. Data analysis was performed using RevMan 5.3 and Stata 17.0, with evaluations for heterogeneity and publication bias. Additionally, subgroup analyses were stratified based on the duration of treatment.

RESULTS

A total of 40 studies involving 3,934 participants were included in the meta-analysis. Both HJD monotherapy and combined with other therapies significantly reduced hemoglobin A1C (HbA1c) fasting blood glucose (FBG) and 2-h postprandial glucose (2hPG) levels, as well as improved insulin resistance. Furthermore, combination therapy enhanced the efficacy rate and favorably altered lipid profiles, including increasing HDL-C and decreasing LDL-C, TC, and TG levels. It was worth noting that the results of the subgroup analysis indicated that, in terms of reducing HbA1c and 2hPG, the efficacy of HJD alone for a duration of less than 3 months was found to be potentially superior to that observed in treatments exceeding 3 months. Adverse event assessment suggested that HJD did not increase the incidence of side effects, including diarrhea, affirming its safety.

CONCLUSION

HJD appears to be an effective and safe alternative or adjunctive therapy for T2DM, showing significant improvements in glycemic control and lipid profiles without increasing adverse events. Further rigorous, multicenter RCTs outside China are warranted to validate these findings.

Ziel

Diabetes mellitus Typ 2 (DMT2) ist eine weit verbreitete Stoffwechselerkrankung, und es besteht ein steigendes Interesse an den potenziellen Vorteilen der traditionellen chinesischen Medizin, wie beispielsweise Huanglian Jiedu-Dekokt (HJD), zu seiner Behandlung. Mit dieser Metaanalyse sollten die Wirksamkeit und Sicherheit von HJD zur Behandlung von DMT2 ermittelt werden.

Methoden

Es wurde eine systematische Recherche in sechs Datenbanken durchgeführt, darunter PubMed, Embase, Cochrane, Web of Science, China National Knowledge Infrastructure (CNKI) und Wanfang, für die Zeit vom Beginn der Datenbank bis zum 24. August 2023. Dabei lag unser Hauptaugenmerk auf randomisierten kontrollierten Studien (RCTs), die HJD sowohl als Monotherapie als auch in Kombinationstherapien bei Patienten mit DMT2 untersuchten. Die Datenanalyse erfolgte mithilfe von RevMan 5.3 und Stata 17.0 mit Untersuchungen auf Heterogenität und Publikationsverzerrungen. Darüber hinaus wurden Subgruppenanalysen stratifiziert nach Behandlungsdauer durchgeführt.

Ergebnisse

Insgesamt wurden 40 Studien mit 3.934 Teilnehmern in die Metaanalyse eingeschlossen. HJD führte sowohl als Monotherapie als auch in Kombination mit anderen Therapien zu einer signifikanten Senkung des HbA1c-Nüchternblutzuckerspiegels (fasting blood glucose, FBG) und der postprandialen Blutzuckerwerte 2 Stunden nach dem Essen (2-h postprandial glucose, 2hPG) sowie zu einer Verbesserung der Insulinresistenz. Darüber hinaus verbesserte die Kombinationstherapie die Wirksamkeitsrate und führte zu einer positiven Veränderung der Lipidprofile, die eine Erhöhung der HDL-Cholesterinwerte und eine Senkung der LDL-, Gesamtcholesterin- und Trigylceridwerte einschloss. Erwähnenswert ist, dass nach den Ergebnissen der Subgruppenanalyse die Wirksamkeit von HJD als Monotherapie in Hinblick auf die Senkung der HbA1c- und 2hPG-Werte bei einer Behandlungsdauer von weniger als drei Monaten gegenüber derjenigen von Behandlungen, die länger als drei Monate dauerten, potenziell überlegen war. Die Bewertung der unerwünschten Ereignisse zeigte, dass HJD nicht zu einem Anstieg der Nebenwirkungen wie Durchfall führte, was seine Sicherheit bestätigte.

Schlussfolgerung

HJD scheint eine wirksame und sichere Alternative oder Zusatztherapie bei DMT2 zu sein, die signifikante Verbesserungen der Blutzuckerkontrolle und der Lipidprofile ohne Zunahme der unerwünschten Ereignisse bewirkt. Weitere rigorose, multizentrische RCTs außerhalb Chinas sind erforderlich, um diese Ergebnisse zu validieren.

Peroxisome Proliferator-Activated Receptor agonists and antagonists: an updated patent review (2020-2023)

INTRODUCTION

The search for novel compounds targeting Peroxisome Proliferator-Activated Receptors (PPARs) is currently ongoing, starting from the previous successfully identification of selective, dual or pan agonists. In last years, researchers' efforts are mainly paid to the discovery of PPARγ and δ modulators, both agonists and antagonists, selective or with a dual-multitarget profile. Some of these compounds are currently under clinical trials for the treatment of primary biliary cirrhosis, nonalcoholic fatty liver disease, hepatic, and renal diseases.

AREAS COVERED

A critical analysis of patents deposited in the range 2020-2023 was carried out. The novel compounds discovered were classified as selective PPAR modulators, dual and multitarget PPAR agonists. The use of PPAR ligands in combination with other drugs was also discussed, together with novel therapeutic indications proposed for them.

EXPERT OPINION

From the analysis of the patent literature, the current emerging landscape sees the necessity to obtain PPAR multitarget compounds, with a balanced potency on three subtypes and the ability to modulate different targets. This multitarget action holds great promise as a novel approach to complex disorders, as metabolic, inflammatory diseases, and cancer. The utility of PPAR ligands in the immunotherapy field also opens an innovative scenario, that could deserve further applications.

AM1638, a GPR40-Full Agonist, Inhibited Palmitate- Induced ROS Production and Endoplasmic Reticulum Stress, Enhancing HUVEC Viability in an NRF2-Dependent Manner

BACKGRUOUND

G protein-coupled receptor 40 (GPR40) is a key molecule in diabetes and fatty liver, but its role in endothelial dysfunction remains unclear. Our objective in this study was to determine whether GPR40 agonists protect endothelial cells against palmitatemediated oxidative stress.

METHODS

Human umbilical vein endothelial cells (HUVECs) were used to investigate effects of various GPR40 agonists on vascular endothelium.

RESULTS

In HUVECs, AM1638, a GPR40-full agonist, enhanced nuclear factor erythroid 2-related factor 2 (NRF2) translocation to the nucleus and heme oxygenase-1 (HO-1) expression, which blocked palmitate-induced superoxide production. Those antioxidant effects were not detected after treatment with LY2922470 or TAK875, GPR40-partial agonists, suggesting that GPR40 regulates reactive oxygen species (ROS) removal in a ligand-dependent manner. We also found that palmitate-induced CCAAT/enhancer-binding protein homologous protein expression; X-box binding protein-1 splicing, nuclear condensation, and fragmentation; and caspase-3 cleavage were all blocked in an NRF2-dependent manner after AM1638 treatment. Both LY2922470 and TAK875 also improved cell viability independent of the NRF2/ROS pathway by reducing palmitate-mediated endoplasmic reticulum stress and nuclear damage. GPR40 agonists thus have beneficial effects against palmitate in HUVECs. In particular, AM1638 reduced palmitate-induced superoxide production and cytotoxicity in an NRF2/HO-1 dependent manner.

CONCLUSION

GPR40 could be developed as a good therapeutic target to prevent or treat cardiovascular diseases such as atherosclerosis.

Predicting GPR40 Agonists with A Deep Learning-Based Ensemble Model

Recent studies have identified G protein-coupled receptor 40 (GPR40) as a promising target for treating type 2 diabetes mellitus, and GPR40 agonists have several superior effects over other hypoglycemic drugs, including cardiovascular protection and suppression of glucagon levels. In this study, we constructed an up-to-date GPR40 ligand dataset for training models and performed a systematic optimization of the ensemble model, resulting in a powerful ensemble model (ROC AUC: 0.9496) for distinguishing GPR40 agonists and non-agonists. The ensemble model is divided into three layers, and the optimization process is carried out in each layer. We believe that these results will prove helpful for both the development of GPR40 agonists and ensemble models. All the data and models are available on GitHub. (https://github.com/Jiamin-Yang/ensemble_model).

Blood-Brain Barrier Disruption Mediated by FFA1 Receptor-Evidence Using Miniscope

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), obtained from diet and dietary supplements, have been tested in clinical trials for the prevention or treatment of several diseases. n-3 PUFAs exert their effects by activation of free fatty acid (FFA) receptors. FFA1 receptor, expressed in the pancreas and brain, is activated by medium- to long-chain fatty acids. Despite some beneficial effects on cognition, the effects of n-3 PUFAs on the blood-brain barrier (BBB) are not clearly understood. We examined the effects of FFA1 activation on BBB permeability in vitro, using rat brain microvascular endothelial cells (RBMVEC), and in vivo, by assessing Evans Blue extravasation and by performing live imaging of brain microcirculation in adult rats. AMG837, a synthetic FFA1 agonist, produced a dose-dependent decrease in RBMVEC monolayer resistance assessed with Electric Cell-Substrate Impedance Sensing (ECIS); the effect was attenuated by the FFA1 antagonist, GW1100. Immunofluorescence studies revealed that AMG837 produced a disruption in tight and adherens junction proteins. AMG837 increased Evans Blue content in the rat brain in a dose-dependent manner. Live imaging studies of rat brain microcirculation with miniaturized fluorescence microscopy (miniscope) showed that AMG837 increased extravasation of sodium fluorescein. Taken together, our results demonstrate that FFA1 receptor activation reduced RBMVEC barrier function and produced a transient increase in BBB permeability.

Evaluation of the hepatotoxicity of the novel GPR40 (FFAR1) agonist CPL207280 in the rat and monkey

GPR40 (FFAR1) is a promising target for the managing type 2 diabetes (T2D). The most advanced GPR40 agonist TAK-875 exhibited satisfactory glucose-lowering effects in phase II and III studies. However, the phase III studies of TAK-875 revealed drug-induced liver injury (DILI). It is unknown whether DILI is a consequence of a specific GPR40 agonist or is an inherent feature of all GPR40 agonists. CPL207280 is a novel GPR40 agonist that improves diabetes in Zucker Diabetic Fatty (ZDF) rats, Goto Kakizaki (GK) rats and db/db mice. In this report, the DILI-related toxicity of CPL207280 was compared directly with that of TAK-875. In vitro studies evaluating hepatic biliary transporter inhibition, mitochondrial function, and metabolic profiling were performed in hepatocytes from different species. The long term toxicity of CPL207280 was studied in vivo in rats and monkeys. Activity of CPL207280 was one order of magnitude lesser than that of TAK-875 for the inhibition of bile acid transporters. CPL207280 had a negligible effect on the hepatic mitochondria. In contrast to TAK-875, which was metabolized through toxic glucuronidation, CPL207280 was metabolized mainly through oxidation. No deleterious hepatic effects were observed in chronically treated healthy and diabetic animals. The study presents promising data on the feasibility of creating a liver-safe GPR40 agonist. Additionally, it can be concluded that DILI is not a hallmark of GPR40 agonists; it is linked to the intrinsic properties of an individual agonist.

Discovery and development of CPL207280 as new GPR40/FFA1 agonist

Due to a unique mechanism that limits the possibility of hypoglycemia, the free fatty acid receptor (FFA1) is an attractive target for the treatment of type 2 diabetes. So far, however, none of the promising agonists have been able to enter the market. The most advanced clinical candidate, TAK-875, was withdrawn from phase III clinical trials due to liver safety issues. In this article, we describe the key aspects leading to the discovery of CPL207280 (13), the design of which focused on long-term safety. The introduction of small, nature-inspired acyclic structural fragments resulted in compounds with retained high potency and a satisfactory pharmacokinetic profile. Optimized synthesis and upscaling provided a stable, solid form of CPL207280-51 (45) with the properties required for the toxicology studies and ongoing clinical trials.