Isoliquiritigenin alleviates diabetic symptoms via activating AMPK and inhibiting mTORC1 signaling in diet-induced diabetic mice

Dynamin-related protein 1 mediates the therapeutic effect of isoliquiritigenin in diabetic intimal hyperplasia via regulation of mitochondrial fission

Phenotypic shift of vascular smooth muscle cells (VSMCs) plays a key role in intimal hyperplasia, especially in patients with diabetes mellitus (DM). This study aimed to investigate the role of dynamin-related protein 1 (DRP1) in mitochondrial fission-mediated VSMC phenotypic shift and to clarify whether DRP1 is the therapeutic target of isoliquiritigenin (ISL). Wire injury of carotid artery or platelet-derived growth factor treatment was performed in DM mice or high-glucose cultured human aortic smooth muscle cells (HASMCs), respectively. The effects of DRP1 silencing on DM-induced intimal hyperplasia were investigated both in vivo and in vitro. Phenotypic shift of HASMCs was evaluated by detection of reactive oxygen species (ROS) generation, cell viability, and related protein expressions. The effects of ISL on DM-induced intimal hyperplasia were evaluated both in vivo and in vitro. DRP1 silencing and ISL treatment attenuated DM-induced intimal hyperplasia with reduced ROS generation, cell viability, and VSMC dedifferentiation. The GTPase domain of DRP1 protein played a critical role in mitochondrial fission in DM-induced VSMC phenotypic shift. Cellular experiments showed that ISL inhibited mitochondrial fission and reduced the GTPase activity of DRP1, which was achieved by the directly binding to K216 of the DRP1 GTPase domain. ISL attenuated mouse intimal hyperplasia by reducing GTPase activity of DRP1 and inhibiting mitochondrial fission in vivo. In conclusion, increased GTPase activity of DRP1 aggregated DM-induced intimal hyperplasia by increasing mitochondrial fission-mediated VSMC phenotypic shift. ISL attenuated mouse intimal hyperplasia by reducing DRP1 GTPase activity and inhibiting mitochondrial fission of VSMCs.

A High-Throughput Screening of a Natural Products Library for Mitochondria Modulators

Mitochondria, the energy hubs of the cell, are progressively becoming attractive targets in the search for potent therapeutics against neurodegenerative diseases. The pivotal role of mitochondrial dysfunction in the pathogenesis of various diseases, including Parkinson's disease (PD), underscores the urgency of discovering novel therapeutic strategies. Given the limitations associated with available treatments for mitochondrial dysfunction-associated diseases, the search for new potent alternatives has become imperative. In this report, we embarked on an extensive screening of 4224 fractions from 384 Australian marine organisms and plant samples to identify natural products with protective effects on mitochondria. Our initial screening using PD patient-sourced olfactory neurosphere-derived (hONS) cells with rotenone as a mitochondria stressor resulted in 108 promising fractions from 11 different biota. To further assess the potency and efficacy of these hits, the 11 biotas were subjected to a subsequent round of screening on human neuroblastoma (SH-SY5Y) cells, using 6-hydroxydopamine to induce mitochondrial stress, complemented by a mitochondrial membrane potential assay. This rigorous process yielded 35 active fractions from eight biotas. Advanced analysis using an orbit trap mass spectrophotometer facilitated the identification of the molecular constituents of the most active fraction from each of the eight biotas. This meticulous approach led to the discovery of 57 unique compounds, among which 12 were previously recognized for their mitoprotective effects. Our findings highlight the vast potential of natural products derived from Australian marine organisms and plants in the quest for innovative treatments targeting mitochondrial dysfunction in neurodegenerative diseases.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatment of diabetes and its complications: An update since 2010

Diabetes, characterized as a well-known chronic metabolic syndrome, with its associated complications pose a substantial and escalating health and healthcare challenge on a global scale. Current strategies addressing diabetes are mainly symptomatic and there are fewer available curative pharmaceuticals for diabetic complications. Thus, there is an urgent need to identify novel pharmacological targets and agents. The impaired mitochondria have been associated with the etiology of diabetes and its complications, and the intervention of mitochondrial dysfunction represents an attractive breakthrough point for the treatments of diabetes and its complications. Natural products (NPs), with multicenter characteristics, multi-pharmacological activities and lower toxicity, have been caught attentions as the modulators of mitochondrial functions in the therapeutical filed of diabetes and its complications. This review mainly summarizes the recent progresses on the potential of 39 NPs and 2 plant-extracted mixtures to improve mitochondrial dysfunction against diabetes and its complications. It is expected that this work may be useful to accelerate the development of innovative drugs originated from NPs and improve upcoming therapeutics in diabetes and its complications.

Isoliquiritigenin, a potential therapeutic agent for treatment of inflammation-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is a medicinal herb with a 2000-year history of applications in traditional Chinese medicine. Isoliquiritigenin (ISL) is a bioactive chalcone compound isolated from licorice. It has attracted increasing attention in recent years due to its excellent anti-inflammatory activity.

AIM OF THE STUDY

This study is to provide a comprehensive summary of the anti-inflammatory activity of ISL and the underlying molecular mechanisms, and discuss new insights for its potential clinical applications as an anti-inflammation agent.

MATERIALS AND METHODS

We examined literatures published in the past twenty years from PubMed, Research Gate, Web of Science, Google Scholar, and SciFinder, with single or combined key words of "isoliquiritigenin", "inflammation", and "anti-inflammatory".

RESULTS

ISL elicits its anti-inflammatory activity by mediating various cellular processes. It inhibits the upstream of the nuclear factor kappa B (NF-κB) pathway and activates the nuclear factor erythroid related factor 2 (Nrf2) pathway. In addition, it suppresses the NOD-like receptor protein 3 (NLRP3) pathway and restrains the mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

Current studies indicate a great therapeutical potential of ISL as a drug candidate for treatment of inflammation-associated diseases. However, the pharmacokinetics, biosafety, and bioavailability of ISL remain to be further investigated.

Isoliquiritigenin attenuates high glucose-induced proliferation, inflammation, and extracellular matrix deposition in glomerular mesangial cells by suppressing JAK2/STAT3 pathway

To investigate the effect of isoliquiritigenin (ISL) on high glucose (HG)-induced glomerular mesangial cells (GMCs) proliferation, extracellular matrix (ECM) deposition and inflammation, and the underlying mechanisms. Mouse GMCs (SV40-MES-13) were cultured in HG medium, with or without ISL. The proliferation of GMCs was determined by MTT assay. The production of proinflammatory cytokines was detected by qRT-PCR and ELISA. The expression of connective tissue growth factor (CTGF), TGF-β1, collagen IV, and fibronectin was measured by qRT-PCR and western blot. The phosphorylation of JAK2 and STAT3 was examined by western blot. Next, JAK2 inhibitor AG490 was applied to HG-exposed GMCs. The levels of JAK2/STAT3 phosphorylation and pro-fibrotic markers were analyzed by western blot, and the secretion of TNF-α and IL-1β was evaluated by ELISA. GMCs were treated with HG, HG plus ISL or HG plus ISL, and recombinant IL-6 (rIL-6) which is a JAK2 activator. The levels of JAK2/STAT3 activation, ECM formation, and proinflammatory cytokines secretion were determined by western blot and ELISA, respectively. In mouse GMCs, ISL successfully repressed HG-induced hyperproliferation; production of TNF-α and IL-1β; expression of CTGF, TGF-β1, collagen IV, and fibronectin; and activation of JAK2/STAT3. Similar to ISL, AG490 was able to reverse the inflammation and ECM generation caused by HG. Moreover, rIL-6 impeded the amelioration of ISL on HG-induced adverse effects. Our study demonstrated that ISL displayed preventive effects on HG-exposed GMCs through inhibiting JAK2/STAT3 pathway and provided an insight into the application of ISL for diabetic nephropathy (DN) treatment.

Licochalcone A alleviates abnormal glucolipid metabolism and restores energy homeostasis in diet-induced diabetic mice

Licochalcone A (LCA) is a bioactive chalcone compound identified in licorice. This study aimed to investigate the effects of LCA on glucolipid metabolism and energy homeostasis, as well as the underlying mechanisms. Blood glucose levels, oral glucose tolerance, serum parameters, and histopathology were examined in high-fat-high-glucose diet (HFD)-induced diabetic mice, with metformin as a positive control. Additionally, changes in key markers related to glucolipid metabolism and mitochondrial function were analyzed to comprehensively assess LCA's effects on metabolism. The results showed that LCA alleviated metabolic abnormalities in HFD-induced diabetic mice, which were manifested by suppression of lipogenesis, promotion of lipolysis, reduction of hepatic steatosis, increase in hepatic glycogenesis, and decrease in gluconeogenesis. In addition, LCA restored energy homeostasis by promoting mitochondrial biogenesis, enhancing mitophagy, and reducing adenosine triphosphate production. Mechanistically, the metabolic benefits of LCA were associated with the downregulation of mammalian target of rapamycin complex 1 and activation of adenosine monophosphate-activated protein kinase, the two central regulators of metabolism. This study demonstrates that LCA can alleviate abnormal glucolipid metabolism and restore energy balance in diet-induced diabetic mice, highlighting its therapeutical potential for the treatment of diabetes.

Isoliquiritigenin in combination with visceral adipose tissue and related markers as a predictive tool for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world. New non-invasive diagnostic tools are needed to promptly treat this disease and avoid its complications. This study aimed to find key metabolites and related variables that could be used to predict and diagnose NAFLD. Ninety-eight subjects with NAFLD and 45 controls from the Fatty Liver in Obesity (FLiO) Study (NCT03183193) were analyzed. NAFLD was diagnosed and graded by ultrasound and classified into two groups: 0 (controls) and ≥ 1 (NAFLD). Hepatic status was additionally assessed through magnetic resonance imaging (MRI), elastography, and determination of transaminases. Anthropometry, body composition (DXA), biochemical parameters, and lifestyle factors were evaluated as well. Non-targeted metabolomics of serum was performed with high-performance liquid chromatography coupled to time-of-flight mass spectrometry (HPLC-TOF-MS). Isoliquiritigenin (ISO) had the strongest association with NAFLD out of the determinant metabolites. Individuals with higher concentrations of ISO had healthier metabolic and hepatic status and were less likely to have NAFLD (OR 0.13). Receiver operating characteristic (ROC) curves demonstrated the predictive power of ISO in panel combination with other NAFLD and IR-related variables, such as visceral adipose tissue (VAT) (AUROC 0.972), adiponectin (AUROC 0.917), plasmatic glucose (AUROC 0.817), and CK18-M30 (AUROC 0.810). Individuals with lower levels of ISO have from 71 to 82% more risk of presenting NAFLD compared to individuals with higher levels. Metabolites such as ISO, in combination with visceral adipose tissue, IR, and related markers, constitute a potential non-invasive tool to predict and diagnose NAFLD.

Deep learning-assisted high-content screening identifies isoliquiritigenin as an inhibitor of DNA double-strand breaks for preventing doxorubicin-induced cardiotoxicity

BACKGROUND

Anthracyclines including doxorubicin are essential components of many cancer chemotherapy regimens, but their cardiotoxicity severely limits their use. New strategies for treating anthracycline-induced cardiotoxicity (AIC) are still needed. Anthracycline-induced DNA double-strand break (DSB) is the major cause of its cardiotoxicity. However, DSB-based drug screening for AIC has not been performed possibly due to the limited throughput of common assays for detecting DSB. To discover new therapeutic candidates for AIC, here we established a method to rapidly visualize and accurately evaluate the intranuclear anthracycline-induced DSB, and performed a screening for DSB inhibitors.

RESULTS

First, we constructed a cardiomyocyte cell line stably expressing EGFP-53BP1, in which the formation of EGFP-53BP1 foci faithfully marked the doxorubicin-induced DSB, providing a faster and visible approach to detecting DSB. To quantify the DSB, we used a deep learning-based image analysis method, which showed the better ability to distinguish different cell populations undergoing different treatments of doxorubicin or reference compounds, compared with the traditional threshold-based method. Subsequently, we applied the deep learning-assisted high-content screening method to 315 compounds and found three compounds (kaempferol, kaempferide, and isoliquiritigenin) that exert cardioprotective effects in vitro. Among them, the protective effect of isoliquiritigenin is accompanied by the up-regulation of HO-1, down-regulation of peroxynitrite and topo II, and the alleviation of doxorubicin-induced DSB and apoptosis. The results of animal experiments also showed that isoliquiritigenin maintained the myocardial tissue structure and cardiac function in vivo. Moreover, isoliquiritigenin did not affect the killing of HeLa and MDA-MB-436 cancer cells by doxorubicin and thus has the potential to be a lead compound to exert cardioprotective effects without affecting the antitumor effect of doxorubicin.

CONCLUSIONS

Our findings provided a new method for the drug discovery for AIC, which combines phenotypic screening with artificial intelligence. The results suggested that isoliquiritigenin as an inhibitor of DSB may be a promising drug candidate for AIC.

On demand regulation of blood glucose level by biocompatible oxidized starch-Con A nanogels for glucose-responsive release of exenatide

Diabetes mellitus is a long-term chronic disease characterized by abnormal high level blood glucose (BG). An artificial closed-loop system that mimics pancreatic β-cells and releases insulin on demand has potential to improve the therapeutic efficiency of diabetes. Herein, a lectin Concanavalin A modified oxidized starch nanogel was designed to regulate glucose dynamically according to different glucose concentrations. The nanogels were formed by double cross-linking the Concanavalin A and glucose units on oxidized starch via specific binding and amide bonds to achieve the high drug loading and glucose responsiveness. The results showed that oxidized starch nanogels prolonged the half-life of antidiabetic peptide drug exenatide and released it in response to high BG concentrations. It could absorb BG at a high level and maintain glucose homeostasis. Besides, the oxidized starch nanogels performed well in recovering regular BG level from hyperglycemia state and maintaining in euglycemia state that fitted in a biological rhythm. In addition, the nanogels showed high biocompatibility in vivo and could improve plasma half-life and therapeutic efficacy of exenatide. Overall, the nanogels protected peptide drugs from degradation in plasma as a glucose-responsive platform showing a high potential for peptide drugs delivery and antidiabetic therapy.

Therapeutic potential of non-starch polysaccharides on type 2 diabetes: from hypoglycemic mechanism to clinical trials

Non-starch polysaccharides (NSPs) have been reported to exert therapeutic potential on managing type 2 diabetes mellitus (T2DM). Various mechanisms have been proposed; however, several studies have not considered the correlations between the anti-T2DM activity of NSPs and their molecular structure. Moreover, the current understanding of the role of NSPs in T2DM treatment is mainly based on in vitro and in vivo data, and more human clinical trials are required to verify the actual efficacy in treating T2DM. The related anti-T2DM mechanisms of NSPs, including regulating insulin action, promoting glucose metabolism and regulating postprandial blood glucose level, anti-inflammatory and regulating gut microbiota (GM), are reviewed. The structure-function relationships are summarized, and the relationships between NSPs structure and anti-T2DM activity from clinical trials are highlighted. The development of anti-T2DM medication or dietary supplements of NSPs could be promoted with an in-depth understanding of the multiple regulatory effects in the treatment/intervention of T2DM.

Isoliquiritigenin Inhibits Gastric Cancer Stemness, Modulates Tumor Microenvironment, and Suppresses Tumor Growth through Glucose-Regulated Protein 78 Downregulation

Chemotherapy is the treatment of choice for gastric cancer; however, the currently available therapeutic drugs for treatment have limited efficacy. Cancer stemness and the tumor microenvironment may play crucial roles in tumor growth and chemoresistance. Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum chaperone facilitating protein folding and cell homeostasis during stress and may participate in chemoresistance. Isoliquiritigenin (ISL) is a bioactive flavonoid found in licorice. In this study, we demonstrated the role of GRP78 in gastric cancer stemness and evaluated GRP78-mediated stemness inhibition, tumor microenvironment regulation, and chemosensitivity promotion by ISL. ISL not only suppressed GRP78-mediated gastric cancer stem cell–like characteristics, stemness-related protein expression, and cancer-associated fibroblast activation but also gastric tumor growth in xenograft animal studies. The findings indicated that ISL is a promising candidate for clinical use in combination chemotherapy.