OBJECTIVE: To elucidate the effect of Huanglian-Renshen-Decoction (HRD) on ameliorating type 2 diabetes mellitus by maintaining islet β -cell identity through regulating paracrine and endocrine glucagon-like peptide-1 (GLP-1)/GLP-1 receptor (GLP-1R) in both islet and intestine. METHODS: The db/db mice were divided into the model (distilled water), low-dose HRD (LHRD, 3 g/kg), high-dose HRD (HHRD, 6 g/kg), and liraglutide (400 µ g/kg) groups using a random number table, 8 mice in each group. The db/m mice were used as the control group (n=8, distilled water). The entire treatment of mice lasted for 6 weeks. Blood insulin, glucose, and GLP-1 levels were quantified using enzyme-linked immunosorbent assay kits. The proliferation and apoptosis factors of islet cells were determined by immunohistochemistry (IHC) and immunofluorescence (IF) staining. Then, GLP-1, GLP-1R, prohormone convertase 1/3 (PC1/3), PC2, v-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MafA), and pancreatic and duodenal homeobox 1 (PDX1) were detected by Western blot, IHC, IF, and real-time quantitative polymerase chain reaction, respectively. RESULTS: HRD reduced the weight and blood glucose of the db/db mice, and improved insulin sensitivity at the same time (P<0.05 or P<0.01). HRD also promoted mice to secrete more insulin and less glucagon (P<0.05 or P<0.01). Moreover, it also increased the number of islet β cell and decreased islet α cell mass (P<0.01). After HRD treatment, the levels of GLP-1, GLP-1R, PC1/3, PC2, MafA, and PDX1 in the pancreas and intestine significantly increased (P<0.05 or P<0.01). CONCLUSION HRD can maintain the normal function and identity of islet β cell, and the underlying mechanism is related to promoting the paracrine and endocrine activation of GLP-1 in pancreas and intestine.
Animals ; Glucagon-Like Peptide 1/metabolism* ; Diabetes Mellitus, Type 2/metabolism* ; Glucagon-Like Peptide-1 Receptor/metabolism* ; Insulin-Secreting Cells/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Male ; Blood Glucose/metabolism* ; Insulin/blood* ; Mice ; Intestinal Mucosa/pathology* ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Islets of Langerhans/pathology*

In this study, araucarene diterpenes, characterized by a pimarene skeleton with a variably oxidized side chain at C-13, were investigated. A total of 16 araucarene diterpenoids and their derivatives were isolated from the woods of Agathis dammara, including 11 previously unreported compounds: dammaradione (1), dammarones D-G (2, 5, 14, 15), dammaric acids B-F (8-12), and dammarol (16). The structures of these new compounds were elucidated using high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS) and one-dimensional/two-dimensional (1D/2D) nuclear magnetic resonance (NMR), while their absolute configurations were determined through the electronic circular dichroism (ECD) exciton chirality method and Snatzke's method. The hypoglycemic activity of all isolated compounds was evaluated using a transgenic zebrafish model, and a structure-activity relationship (SAR) analysis was conducted. Araucarone (3) and dammaric acid C (9), serving as representative compounds, demonstrated significant hypoglycemic effects on zebrafish. The primary mechanism involves the promotion of pancreatic β cell regeneration and glucose uptake. Specifically, these compounds enhance the differentiation of pancreatic endocrine precursor cells (PEP cells) into β cells in zebrafish.
Zebrafish ; Animals ; Diterpenes/isolation & purification* ; Insulin-Secreting Cells/cytology* ; Glucose/metabolism* ; Hypoglycemic Agents/isolation & purification* ; Molecular Structure ; Structure-Activity Relationship ; Plant Extracts/pharmacology* ; Regeneration/drug effects*

Lycopene is an antioxidant which has potential anti-diabetic activity, but the cellular mechanisms have not been clarified. In this study, different concentrations of lycopene were used to treat pancreatic alpha and beta cell lines, and the changes of cell growth, cell apoptosis, cell cycle, reactive oxygen species (ROS), ATP levels and expression of related cytokines were determined. The results exhibited that lycopene did not affect cell growth, cell apoptosis, cell cycle, ROS and ATP levels of alpha cells, while it promoted the growth of beta cells, increased the ratio of S phase, reduced the ROS levels and increased the ATP levels of beta cells. At the same time, lycopene treatment elevated the mRNA expression levels of tnfα, tgfβ and hif1α in beta cells. These findings suggest that lycopene plays cell-specific role and activates pancreatic beta cells, supporting its application in diabetes therapy.
Adenosine Triphosphate ; metabolism ; Apoptosis ; Carotenoids ; pharmacology ; Cell Cycle ; Cells, Cultured ; Cytokines ; metabolism ; Glucagon-Secreting Cells ; drug effects ; Humans ; Insulin-Secreting Cells ; drug effects ; Lycopene ; pharmacology ; Reactive Oxygen Species ; metabolism

Inhibition of CD36, a fatty acid transporter, has been reported to prevent glucotoxicity and ameliorate high glucose induced beta cell dysfunction. Ezetimibe is a selective cholesterol absorption inhibitor that blocks Niemann Pick C1-like 1 protein, but may exert its effect through suppression of CD36. We attempted to clarify the beneficial effect of ezetimibe on insulin secreting cells and to determine whether this effect is related to change of CD36 expression. mRNA expression of insulin and CD36, intracellular peroxide level and glucose stimulated insulin secretion (GSIS) under normal (5.6 mM) or high glucose (30 mM) condition in INS-1 cells and primary rat islet cells were compared. Changes of the aforementioned factors with treatment with ezetimibe (20 μM) under normal or high glucose condition were also assessed. mRNA expression of insulin was decreased with high glucose, which was reversed by ezetimibe in both INS-1 cells and primary rat islets. CD36 mRNA expression was increased with high glucose, but decreased by ezetimibe in INS-1 cells and primary rat islets. Three-day treatment with high glucose resulted in an increase in intracellular peroxide level; however, it was decreased by treatment with ezetimibe. Decrease in GSIS by three-day treatment with high glucose was reversed by ezetimibe. Palmitate uptake following exposure to high glucose conditions for three days was significantly elevated, which was reversed by ezetimibe in INS-1 cells. Ezetimibe may prevent glucotoxicity in pancreatic β-cells through a decrease in fatty acid influx via inhibition of CD36.
Animals ; Anticholesteremic Agents/*pharmacology ; Antigens, CD36/antagonists & inhibitors/genetics/*metabolism ; Cells, Cultured ; Ezetimibe/*pharmacology ; Flow Cytometry ; Glucose/toxicity ; Insulin/genetics/metabolism/secretion ; Insulin-Secreting Cells/cytology/*drug effects/metabolism ; Male ; Palmitic Acid/metabolism ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species/metabolism ; Real-Time Polymerase Chain Reaction

OBJECTIVETo investigate the effects of berberine (BBR) and cinnamic acid (CA), the main active components in Jiaotai Pill (, JTP), on palmitic acid (PA)-induced intracellular triglyceride (TG) accumulation in NIT-1 pancreatic β cells.

METHODSCells were incubated in culture medium containing PA (0.25 mmol/L) for 24 h. Then treatments with BBR (10 μmol/L), CA (100 μmol/L) and the combination of BBR and CA (BBR+CA) were performed respectively. Intracellular lipid accumulation was assessed by Oil Red O staining and TG content was measured by colorimetric assay. The expression of adenosine monophosphate-activated protein kinase (AMPK) protein and its downstream lipogenic and fatty acid oxidation genes, including fatty acid synthase (FAS), acetyl-coA carboxylase (ACC), phosphorylation acetyl-coA carboxylase (pACC), carnitine acyl transferase 1 (CPT-1) and sterol regulating element binding protein 1c (SREBP-1c) were determined by Western blot or real time polymerase chain reaction.

RESULTSPA induced an obvious lipid accumulation and a significant increase in intracellular TG content in NIT-1 cells. PA also induced a remarkable decrease in AMPK protein expression and its downstream targets such as pACC and CPT-1. Meanwhile, AMPK downstream lipogenic genes including SREBP-1c mRNA, FAS and ACC protein expressions were increased. Treatments with BBR and BBR+CA, superior to CA, significantly reversed the above genes changes in NIT-1 pancreatic β cells. However, the synergistic effect of BBR and CA on intracellular TG content was not observed in the present study.

CONCLUSIONIt can be concluded that in vitro, BBR and BBR+CA could inhibit PA-induced lipid accumulation by decreasing lipogenesis and increasing lipid oxidation in NIT-1 pancreatic β cells.

AMP-Activated Protein Kinases ; metabolism ; Animals ; Berberine ; chemistry ; pharmacology ; Cell Line ; Cinnamates ; chemistry ; pharmacology ; Fatty Acids ; metabolism ; Gene Expression Regulation ; drug effects ; Insulin-Secreting Cells ; drug effects ; metabolism ; Intracellular Space ; metabolism ; Lipogenesis ; drug effects ; genetics ; Mice ; Oxidation-Reduction ; drug effects ; Palmitic Acid ; toxicity ; Triglycerides ; metabolism

Mammalian pancreatic β-cells play a pivotal role in development and glucose homeostasis through the production and secretion of insulin. Functional failure or decrease in β-cell number leads to type 2 diabetes (T2D). Despite the physiological importance of β-cells, the viability of β-cells is often challenged mainly due to its poor ability to adapt to their changing microenvironment. One of the factors that negatively affect β-cell viability is high concentration of free fatty acids (FFAs) such as palmitate. In this work, we demonstrated that Yes-associated protein (Yap1) is activated when β-cells are treated with palmitate. Our loss- and gain-of-function analyses using rodent insulinoma cell lines revealed that Yap1 suppresses palmitate-induced apoptosis in β-cells without regulating their proliferation. We also found that upon palmitate treatment, re-arrangement of F-actin mediates Yap1 activation. Palmitate treatment increases expression of one of the Yap1 target genes, connective tissue growth factor (CTGF). Our gain-of-function analysis with CTGF suggests CTGF may be the downstream factor of Yap1 in the protective mechanism against FFA-induced apoptosis.
Actins ; metabolism ; Adaptor Proteins, Signal Transducing ; antagonists & inhibitors ; genetics ; metabolism ; Animals ; Apoptosis ; drug effects ; physiology ; Bridged Bicyclo Compounds, Heterocyclic ; pharmacology ; Cell Line, Tumor ; Connective Tissue Growth Factor ; genetics ; metabolism ; pharmacology ; Cytochalasin D ; pharmacology ; Fatty Acids, Nonesterified ; pharmacology ; HEK293 Cells ; Humans ; Immunohistochemistry ; Insulin-Secreting Cells ; cytology ; drug effects ; metabolism ; Mice ; Microscopy, Fluorescence ; Palmitic Acid ; pharmacology ; Phosphoproteins ; antagonists & inhibitors ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Rats ; Recombinant Proteins ; genetics ; metabolism ; pharmacology ; Thiazolidines ; pharmacology

Menopausal metabolic syndrome (MMS) is a series of syndrome caused by ovarian function decline and hormone insufficiency, and is a high risk factor for cardiovascular diseases (CVD) and type II diabetes mellitus (T2DM). Erzhiwan (EZW), composed of Herba Ecliptae and Fructus Ligustri Lucidi, is a traditional Chinese herbal formula that has been used to treat menopausal syndrome for many years. We added Herba Epimedii, Radix Rehmanniae, and Fructus Corni into EZW, to prepare a new formula, termed Jiawei Erzhiwan (JE). The present study was designed to determine the anti-MMS effects of JE using ovariectomized (OVX) adult female rats that were treated with JE for 4 weeks, and β-tc-6 cells and INS cells were used to detected the protect effectiveness of JE. Our results showed JE could increase insulin sensitivity and ameliorated hyperlipidemia. Metabolomics analysis showed that the serum levels of branched and aromatic amino acids were down-regulated in serum by JE administration. Moreover, JE enhanced the function of islet β cells INS-1 and β-tc-6, through increasing the glucose stimulated insulin secretion (GSIS), which was abolished by estrogen receptor (ER) antagonist, indicating that JE functions were mediated by ER signaling. Additionally, JE did not induce tumorigenesis in rat mammary tissue or promoted proliferation of MCF-7 and Hela cells. In conclusion, our work demonstrated that JE ameliorated OVX-induced glucose and lipid metabolism disorder through activating estrogen receptor pathway and promoting GSIS in islet β cells, thus indicating that JE could be a safe and effective medication for MMS therapy.
Animals ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Glucose ; metabolism ; Humans ; Insulin ; metabolism ; Insulin Secretion ; Insulin-Secreting Cells ; drug effects ; metabolism ; Menopause ; drug effects ; metabolism ; Metabolic Syndrome ; drug therapy ; metabolism ; Mice ; Rats ; Rats, Sprague-Dawley

To investigate the effects of 2-(4-methoxycarbonyl-2-tetradecyloxyphenyl)carbamoylbenzoic acid (CX09040) on protecting pancreatic β cells, the β cell dysfunction model mice were induced by injection of alloxan into the caudal vein of ICR mice, and were treated with compound CX09040. Liraglutide was used as the positive control drug. The amount and the size of islets observed in pathological sections were calculated to evaluate the β cell mass; the glucose stimulated insulin secretion (GSIS) test was applied to estimate the β cell secretary function; the oral glucose tolerance test (OGTT) was taken to observe the glucose metabolism in mice; the expressions of protein in pancreas were detected by Western blotting. The effects on the target protein tyrosine phosphatase 1B (PTP1B) were assessed by the PTP1B activities of both recombinant protein and the intracellular enzyme, and by the PTP1B expression in the pancreas of mice, separately. As the results, with the treatment of CX09040 in alloxan-induced β cell dysfunction mice, the islet amount (P<0.05) and size (P<0.05) increased significantly, the changes of serum insulin in GSIS (P<0.01) and the values of acute insulin response (AIR, P<0.01) were enhanced, compared to those in model group; the impaired glucose tolerance was also ameliorated by CX09040 with the decrease of the values of area under curve (AUC, P<0.01). The activation of the signaling pathways related to β cell proliferation was enhanced by increasing the levels of p-Akt/Akt (P<0.01), p-FoxO1/FoxOl (P<0.001) and PDX-1 (P<0.01). The effects of CX09040 on PTP1B were observed by inhibiting the recombinant hPTP1B activity with IC50 value of 2.78x 10(-7) mol.L-1, reducing the intracellular PTP1B activity of 72.8% (P<0.001), suppressing the PTP1B expression (P<0.001) and up-regulating p-IRβ/IRβ (P<0.01) in pancreas of the β cell dysfunction mice, separately. In conclusion, compound CX09040 showed significant protection effects against the dysfunction of β cell of mice by enlarging the pancreatic β cell mass and increasing the glucose-induced insulin secretion; its major mechanism may be the inhibition on target PTP1B and the succedent up-regulation of β cell proliferation.
Alloxan ; Animals ; Benzoates ; pharmacology ; Biological Assay ; Disease Models, Animal ; Glucose ; metabolism ; Glucose Tolerance Test ; Insulin ; secretion ; Insulin Resistance ; Insulin-Secreting Cells ; drug effects ; Liraglutide ; pharmacology ; Mice ; Mice, Inbred ICR ; Molecular Weight ; Pancreas ; drug effects ; enzymology ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; antagonists & inhibitors ; Signal Transduction

Due to substantial morbidity and high complications, diabetes mellitus is considered as the third "killer" in the world. Medicinal fungal polysaccharides, as water-soluble macromolecular substances with low toxicity, exhibit diversified pharmacological actions such as immune regulation, anti-tumor, antivirus, antioxidant, anti-aging, hypoglycemic effect and improving liver and kidney function. In recent year, a number of investigators reported medicinal fungal polysaccharides showed good anti-diabetes and hypoglycemic activity, and their acting mechanisms involved in glycometabolism and β cell function, e. g. promoting glycogen synthesis, promoting glycolysis, inhibiting the activity of α-glucosidase, promoting insulin secretion, increasing insulin sensitivity, enhancing antioxidation. Therefore, the hypoglycemic activity and its mechanisms of action of medicinal fungal polysaccharides showed characteristics of multiple effects, multi-target, and multi-pathway regulation. These finding suggest that medicinal fungal polysaccharides are a promising source for the development of discovery of anti-diabetic agent.
Animals ; Carbohydrate Metabolism ; drug effects ; Fungal Polysaccharides ; pharmacology ; Humans ; Hypoglycemic Agents ; pharmacology ; Insulin Resistance ; Insulin-Secreting Cells ; drug effects ; Oxidative Stress ; drug effects

Insulin resistance and insulin secretion deficiency are main machanisms in inducing type 2 diabetes mellitus (T2DM), and mitochondria damage plays an important role in them. Research shows that autophagy is a self-protective mechanism of cells, which plays an important role in maintaining the normal structure and function of pancreatic β cells and improving insulin resistance. Previous studies show that traditional Chinese medicine can regulate cell autophagy to influence β cells and insulin resistance, type 2 diabetes mellitus and its complications. Thus this review will talk about the process of the relationship between autophagy and T2DM and the intervention effect of traditional Chinese medicine.
Animals ; Autophagy ; drug effects ; Diabetes Mellitus, Type 2 ; drug therapy ; metabolism ; physiopathology ; Drugs, Chinese Herbal ; therapeutic use ; Humans ; Insulin ; metabolism ; Insulin Resistance ; Insulin-Secreting Cells ; cytology ; drug effects ; metabolism