Ginsenoside Rk1 Ameliorates ER Stress-Induced Apoptosis through Directly Activating IGF-1R in Mouse Pancreatic [Formula: see text]-Cells and Diabetic Pancreas.

Hyperglycemia induces chronic stresses, such as oxidative stress and endoplasmic reticulum (ER) stress, which can result in [Formula: see text]-cell dysfunction and development of Type 2 Diabetes Mellitus (T2DM). Ginsenoside Rk1 is a minor ginsenoside isolated from Ginseng. It has been shown to exert anti-cancer, anti-inflammatory, anti-oxidant, and neuroprotective effects; however, its effects on pancreatic cells in T2DM have never been studied. This study aims to examine the novel effects of Ginsenoside Rk1 on ER stress-induced apoptosis in a pancreatic [Formula: see text]-cell line MIN6 and HFD-induced diabetic pancreas, and their underlying mechanisms. We demonstrated that Ginsenoside Rk1 alleviated ER stress-induced apoptosis in MIN6 cells, which was accomplished by directly targeting and activating insulin-like growth factor 1 receptor (IGF-1R), thus activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/Bcl-2-associated agonist of cell death (Bad)-B-cell lymphoma-2 (Bcl-2) pathway. This pathway was also confirmed in an HFD-induced diabetic pancreas. Meanwhile, the use of the IGF-1R inhibitor PQ401 abolished this anti-apoptotic effect, confirming the role of IGF-1R in mediating anti-apoptosis effects exerted by Ginsenoside Rk1. Besides, Ginsenoside Rk1 reduced pancreas weights and increased pancreatic insulin contents, suggesting that it could protect the pancreas from HFD-induced diabetes. Taken together, our study provided novel protective effects of Ginsenoside Rk1 on ER stress-induced [Formula: see text]-cell apoptosis and HFD-induced diabetic pancreases, as well as its direct target with IGF-1R, indicating that Ginsenoside Rk1 could be a potential drug for the treatment of T2DM.

Glycyrrhizic Acid and Its Derivatives: Promising Candidates for the Management of Type 2 Diabetes Mellitus and Its Complications.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease, which is characterized by hyperglycemia, chronic insulin resistance, progressive decline in ß-cell function, and defect in insulin secretion. It has become one of the leading causes of death worldwide. At present, there is no cure for T2DM, but it can be treated, and blood glucose levels can be controlled. It has been reported that diabetic patients may suffer from the adverse effects of conventional medicine. Therefore, alternative therapy, such as traditional Chinese medicine (TCM), can be used to manage and treat diabetes. In this review, glycyrrhizic acid (GL) and its derivatives are suggested to be promising candidates for the treatment of T2DM and its complications. It is the principal bioactive constituent in licorice, one type of TCM. This review comprehensively summarized the therapeutic effects and related mechanisms of GL and its derivatives in managing blood glucose levels and treating T2DM and its complications. In addition, it also discusses existing clinical trials and highlights the research gap in clinical research. In summary, this review can provide a further understanding of GL and its derivatives in T2DM as well as its complications and recent progress in the development of potential drugs targeting T2DM.

Specific NLRP3 inflammasome inhibitors: promising therapeutic agents for inflammatory diseases.

Innate immunity serves as a first line of defence against danger signals, invading pathogens and microbes. The inflammasomes, as pattern recognition receptors, sense these danger signals to initiate pro-inflammatory cascades. The nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor 3 (NLRP3) inflammasome is the most well characterised inflammasome, and its aberrant activation is implicated in many inflammatory diseases. In the past decade, targeting the NLRP3 inflammasome has become an emerging strategy for inflammatory diseases. To avoid off-target immunosuppressive effects, specific NLRP3 inhibitors have been developed and show promising therapeutic effects. This review discusses the therapeutic effects and clinical perspectives of specific NLRP3 inhibitors, as well as recent progress in the development of these inhibitors for the treatment of inflammatory diseases.

G-protein coupled receptor 55 agonists increase insulin secretion through inositol trisphosphate-mediated calcium release in pancreatic ß-cells.

G-protein coupled receptor 55 (GPR55) is an orphan G-protein coupled receptor, which is activated by endocannabinoids and lipid transmitters. Recently, GPR55 was shown to play a role in glucose and energy homeostasis, and insulin secretion is essential to maintain glucose homeostasis in the body. In Type 2 Diabetes Mellitus (T2DM), chronic insulin resistance and a progressive decline in ß-cell function result in ß-cell dysfunction, this leads to defect in insulin secretion, which is the key process in the development and progression of T2DM. GPR55 agonists were shown to increase insulin secretion, however the underlying mechanisms were not fully understood. Therefore the aim of the present study was to examine the effects of potent GPR55 agonists, O-1602 and abnormal cannabidiol (Abn-CBD), on glucose-induced insulin secretion in a mouse pancreatic ß-cell line, MIN6, and the underlying mechanisms with a focus on intracellular calcium (Ca2+). Our results demonstrated that O-1602 and Abn-CBD increased glucose-induced insulin secretion in MIN6 cells, which was abolished by a PLC inhibitor, U73122. Glucose-induced Ca2+ transients were enhanced by O-1602 and Abn-CBD, and this was significantly reduced by U73122 and inositol trisphosphate (IP3) receptor inhibitors, 2-aminoethoxydiphenyl borate (2-APB) and xestospongin C, as well as by Y-27632, a Rho-associated protein kinase (ROCK) inhibitor. Interestingly, O-1602 and Abn-CBD could directly induce intracellular Ca2+ transients through IP3-mediated Ca2+ release. In conclusion, GPR55 agonists increased insulin secretion through calcium mobilisation from IP3-sensitive ER stores in ß-cells.

Novel protective effect of O-1602 and abnormal cannabidiol, GPR55 agonists, on ER stress-induced apoptosis in pancreatic ß-cells.

Insulin resistance and ß-cell dysfunction are the main defects in Type 2 Diabetes Mellitus (T2DM), and ß-cell dysfunction and apoptosis is the critical determinant in the progression of T2DM. G-protein coupled receptor 55 (GPR55) is an orphan G-protein coupled receptor, which is activated by endocannabinoids and lipid transmitters. Recently, GPR55 was shown to regulate glucose and energy homeostasis, however its role in ß-cell apoptosis was not studied. Therefore, in this study, we investigated the novel effect of GPR55 agonists, O-1602 and abnormal cannabidiol (Abn-CBD), on endoplasmic reticulum (ER) stress-induced apoptosis in mouse pancreatic ß-cell lines, MIN6 and Beta-TC-6, and its underlying mechanisms. Our results showed that O-1602 and Abn-CBD reduced ER stress-induced apoptosis in MIN6 and Beta-TC-6 cells. This was through the phosphorylation of 3'-5'-cyclic adenosine monophosphate response element-binding protein (CREB) in ß-cells, hence activating CREB downstream anti-apoptotic genes, Bcl-2 and Bcl-xL. Moreover, O-1602 and Abn-CBD directly activated kinases, CaMKIV, Erk1/2 and PKA, to induce CREB phosphorylation. Therefore, our results indicated that GPR55 agonists protected from ß-cell apoptosis through CREB activation, thus up-regulating anti-apoptotic genes. In conclusion, our study provided a novel protective effect of GPR55 agonists on ER stress-induced apoptosis in ß-cells and its underlying mechanisms mediating this protection, therefore we suggested that GPR55 might be a therapeutic target for T2DM.

A novel Ca2+ current blocker promotes angiogenesis and cardiac healing after experimental myocardial infarction in mice.

We previously reported a novel danshensu derivative (R)-(3,5,6-Trimethylpyrazinyl) methyl-2-acetoxy-3-(3,4-diacetoxyphenyl) propanoate (ADTM) that exhibited promising cardiovascular protective activities, such as antioxidant and antiplatelet activities, as well as arterial relaxation. Particularly, ADTM treatment for 24 h exhibited anti-oxidative activity and effectively protected against acute myocardial infarction (MI) in a rat model. Here, we further investigated the pharmacological actions of 14 days of treatment with ADTM in alleviating and restoring the MI size by stimulating revascularization. The pro-angiogenesis activity of ADTM has been validated in multiple experimental models including MI mouse, zebrafish, human umbilical vein endothelial cells (HUVECs) and A7r5 vascular smooth muscle cells (VSMCs). In addition, the effect of ADTM on L-type Ca2+ current (ICaL) was determined. We demonstrated that ADTM (12-24 mg/kg) treatment for 14 days significantly decreased myocardial infarct size, increased the blood vessel density compared to vehicle in the myocardial peri-infarct area, and ADTM (24 mg/kg) enhanced the serum VEGF level in MI mice (P < 0.05). We also demonstrated that treatment with ADTM at 50-200 µM rescued chemical-induced blood vessel loss in zebrafish. Although ADTM did not directly promote the features of angiogenesis in HUVECs, ADTM significantly increased VEGF production in a dose-dependent manner in A7r5 cells (P < 0.05). A patch clamp experiment demonstrated that ADTM (200 µM) inhibited ICaL at all depolarizing voltages, with > 50% inhibition at + 10 mV. Taken together, our results indicated that ADTM served as a Ca2+ current blocker, promoted angiogenesis and reduced experimental myocardial infarct size in mice, probably through stimulation of VEGF production in VSMCs.

Lysosomal Ca2+ Signaling Regulates High Glucose-Mediated Interleukin-1ß Secretion via Transcription Factor EB in Human Monocytic Cells.

Aberrant activation of the innate immune system, including NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome-dependent interleukin-1ß (IL-1ß) secretion, has been implicated in the pathogenesis of type 2 diabetes mellitus (T2DM) and its complication. Our previous study demonstrated that hyperglycemia, a hallmark characteristic of T2DM, induced NLRP3 inflammasome-dependent caspase-1 activation and IL-1ß maturation in human monocytic cells. In this study, we examined the underlying mechanisms of secreting IL-1ß during hyperglycemia, with a focus on the alteration of Ca2+ homeostasis and lysosomal exocytosis. We found that high glucose (HG; 30 mM glucose for 48 h) altered Ca2+ homeostasis by reducing lysosomal Ca2+ concentration that appeared to be resulted from Ca2+ moving out of lysosomes into cytosol in human monocytic cell lines, U937 and THP-1 cells. Moreover, HG-induced lysosomal Ca2+-dependent mature IL-1ß release was strongly correlated with the activation and upregulation of two lysosomal marker proteins, cathepsin D and lysosomal-associated membrane protein-1 (LAMP-1). This involved calcineurin/transcription factor EB (TFEB) pathway and its target genes, cathepsin B, cathepsin D, and LAMP-1, to mediate lysosomal exocytosis. Therefore in this study, we revealed a novel mechanism of HG-induced lysosomal exocytosis which was regulated by lysosomal Ca2+ signals through calcineurin/TFEB pathway, thus contributing to IL-1ß secretion in human monocytic cells.

Calycosin and Formononetin Induce Endothelium-Dependent Vasodilation by the Activation of Large-Conductance Ca2+-Activated K+ Channels (BKCa).

Calycosin and formononetin are two structurally similar isoflavonoids that have been shown to induce vasodilation in aorta and conduit arteries, but study of their actions on endothelial functions is lacking. Here, we demonstrated that both isoflavonoids relaxed rat mesenteric resistance arteries in a concentration-dependent manner, which was reduced by endothelial disruption and nitric oxide synthase (NOS) inhibition, indicating the involvement of both endothelium and vascular smooth muscle. In addition, the endothelium-dependent vasodilation, but not the endothelium-independent vasodilation, was blocked by BKCa inhibitor iberiotoxin (IbTX). Using human umbilical vein endothelial cells (HUVECs) as a model, we showed calycosin and formononetin induced dose-dependent outwardly rectifying K+ currents using whole cell patch clamp. These currents were blocked by tetraethylammonium chloride (TEACl), charybdotoxin (ChTX), or IbTX, but not apamin. We further demonstrated that both isoflavonoids significantly increased nitric oxide (NO) production and upregulated the activities and expressions of endothelial NOS (eNOS) and neuronal NOS (nNOS). These results suggested that calycosin and formononetin act as endothelial BKCa activators for mediating endothelium-dependent vasodilation through enhancing endothelium hyperpolarization and NO production. Since activation of BKCa plays a role in improving behavioral and cognitive disorders, we suggested that these two isoflavonoids could provide beneficial effects to cognitive disorders through vascular regulation.

TRPM2 regulates TXNIP-mediated NLRP3 inflammasome activation via interaction with p47 phox under high glucose in human monocytic cells.

Excessive production of reactive oxygen species (ROS) induced by hyperglycemia increased the secretion of interleukin-1ß (IL-1ß), which contributes to the pathogenesis of diabetes and its complications. Although high glucose (HG)-induced oxidative stress and aberrant Ca2+ channels activity causes an increase in transmembrane Ca2+ influx, however the relative contribution of Transient receptor potential (TRP) channels is not well studied. Here, we identified that HG (30 mM glucose for 48 h) induced the activation of the NLRP3-ASC inflammasome, leading to caspase-1 activation, and IL-1ß and IL-18 secretion in human monocytic cell lines. Moreover, we used a hyperglycemia model in U937 monocytes, showing that the activation of TRPM2 was augmented, and TRPM2-mediated Ca2+ influx was critical for NLRP3 inflammasome activation. This pathway involved NADPH oxidase-dependent ROS production and TXNIP-NLRP3 inflammasome pathway. Furthermore, the inhibition of TRPM2 reduced ROS production and lowered NADPH oxidase activity via cooperatively interaction with p47 phox in response to HG. These results provided a mechanistic linking between TRPM2-mediated Ca2+ influx and p47 phox signaling to induce excess ROS production and TXNIP-mediated NLRP3 inflammasome activation under HG, and suggested that TRPM2 represented a potential target for alleviating NLRP3 inflammasome activation related to hyperglycemia-induced oxidative stress in Type 2 diabetes Mellitus (T2DM).

Antrodia camphorata Increases Insulin Secretion and Protects from Apoptosis in MIN6 Cells.

Antrodia camphorata is a Taiwanese-specific fungus which has been used clinically to treat hypertension, immune- and liver-related diseases and cancer; however, it has never been studied in type 2 diabetes mellitus (T2DM). Hyperglycemia in T2DM causes endoplasmic reticulum (ER) stress, leading to ß-cell dysfunction. During chronic ER stress, misfolded proteins accumulate and initiate ß-cell apoptosis. Moreover, ß-cell dysfunction leads to defect in insulin secretion, which is the key process in the development and progression of T2DM. Therefore, the aim of the present study was to examine the effects of A. camphorata on insulin secretion and ER stress-induced apoptosis in a mouse ß-cell line, MIN6, and their underlying mechanisms. We demonstrated that the ethanolic extract of A. camphorata increased glucose-induced insulin secretion dose-dependently through peroxisome proliferator-activated receptor-γ (PPAR-γ) pathway, and upregulated genes that were involved in insulin secretion, including PPAR-γ, glucose transporter-2 and glucokinase. Furthermore, A. camphorata slightly increased cell proliferation, as well as protected from ER stress-induced apoptosis in MIN6 cells. In conclusion, this study provided evidences that A. camphorata might have anti-diabetic effects and could be a novel drug for T2DM.

Vascular Contributions to Cognitive Impairment and Treatments with Traditional Chinese Medicine.

The prevalence of cognitive impairment and dementia caused by cerebrovascular disease is likely to increase with the global aging population. Vascular contributions to cognitive impairment and dementia (VCID) is a wide spectrum term used to include a diverse heterogeneous group of cognitive syndromes with vascular factors regardless of the cause of pathogenesis. VCID ranges from mild cognitive impairment to full-blown dementia with vascular dementia (VaD) as the most severe stage. It is further complexed by the coexistence of other forms of dementia such as Alzheimer's disease (AD). Recent researches in the functions of the neurovascular unit (NVU) suggest that dysfunction of the NVU might be the cause of primary vascular events in the brain that leads to further neurodegeneration. In this review, we have briefly summarized various forms of VCID. There is currently no standard therapy for VCID or dementia. Given the fact that Traditional Chinese Medicine (TCM) has gained popularity worldwide, we also reviewed recent scientific and clinical findings on various antidementia TCM for the treatment of VCID, including Salvia miltiorrhiza, Huperzia serrata, Ligusticum chuanxiong, Ginkgo biloba, Panax ginseng, and also TCM formula Sailuotong capsule (SLT) and Fufangdanshen tablets (FFDS).

Recent advances in structure-based drug design and virtual screening of VEGFR tyrosine kinase inhibitors.

During the past decade, developments in computational processing and X-ray crystallography have allowed virtual screening become integrated into drug discovery campaigns. This review focuses on the recent advancements in the drug discovery of VEGFR2 tyrosine kinase inhibitors (VEGFR2 TKIs) by using in silico methodologies. An introduction for the methodology framework of pharmacophore modeling, molecular docking and structure-based design are provided. We discuss the recent studies on the structures of VEGFR2 protein kinase in different binding modes, and the insights on molecular interactions gained from knowledge of the co-crystal structures complex with structurally diverse VEGFR2 inhibitors. We provide some aspects of model construction and molecular docking techniques. Several representative examples of successful applications on VEGFR2 virtual screening for hit discovery, lead optimization and structure-based design are also presented.