The effects of troglitazone on AMPK in HepG2 cells

Arctigenin induces activated HSCs quiescence via AMPK-PPARγ pathway to ameliorate liver fibrosis in mice

Arctigenin (ATG), a traditional Chinese herbal medicine, is a natural lignan compound extracted from the seeds of burdock (Arctium lappa L, Asteraceae). As a natural product with multiple biological activities, the effect and mechanism of ATG against liver fibrosis are not fully elucidated yet. In current work, we first discovered that ATG could improve CCl4-induced liver injury reflected by lower plasma ALT and AST levels, liver coefficient and pathological scoring of ballooning. Furthermore, it also could reduce the positive areas of Masson, Sirius red and α-SMA staining, inhibit the expression of fibrosis-related genes (Col1a1, Col3a1, Acta2), and decrease the content of hydroxyproline, indicated ATG treatment had benefits in alleviating CCl4-induced liver fibrosis. In vitro, we observed that ATG can inhibit collagen production stimulated by TGF-β1 in LX2 cells. By analysis of the information obtained from SymMap and GeneCards databases and in vitro validation experiments, ATG was proven to be an indirect PPARγ agonist and its effect on collagen production was dependent on PPARγ. Subsequently, we confirmed that ATG activating AMPK was the contributor of its effect on PPARγ and collagen production. Finally, the transformation of activated hepatic stellate cells was determined after treated with ATG, in which ATG treatment could return activated LX2 cells to quiescence because of the elevated quiescent markers and lipid droplets. Our work has highlighted the potential of ATG in the treatment of liver fibrosis and clarified that ATG can activate AMPK/PPARγ pathway to restore the activated hepatic stellate cell to quiescence thereby improving liver fibrosis.

Loss of AMPK activity induces organelle dysfunction and oxidative stress during oocyte aging

BACKGROUND

Oocyte quality is critical for the mammalian reproduction due to its necessity on fertilization and early development. During aging, the declined oocytes showing with organelle dysfunction and oxidative stress lead to infertility. AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase which is important for energy homeostasis for metabolism. Little is known about the potential relationship between AMPK with oocyte aging.

RESULTS

In present study we reported that AMPK was related with low quality of oocytes under post ovulatory aging and the potential mechanism. We showed the altered AMPK level during aging and inhibition of AMPK activity induced mouse oocyte maturation defect. Further analysis indicated that similar with its upstream regulator PKD1, AMPK could reduce ROS level to avoid oxidative stress in oocytes, and this might be due to its regulation on mitochondria function, since loss of AMPK activity induced abnormal distribution, reduced ATP production and mtDNA copy number of mitochondria. Besides, we also found that the ER and Golgi apparatus distribution was aberrant after AMPK inhibition, and enhanced lysosome function was also observed.

CONCLUSIONS

Taken together, these data indicated that AMPK is important for the organelle function to reduce oxidative stress during oocyte meiotic maturation.

Evaluation of hypoglycemic therapeutics and nutritional supplementation for type 2 diabetes mellitus management: An insight on molecular approaches

OBJECTIVE

This review aims to summarize the current management of type 2 diabetes principles, including oral hypoglycemic agents, types of insulin administration, diet maintenance, and various molecular approaches.

METHODS

A literature search was conducted in different databases such as Scopus, ScienceDirect, Google Scholar, and Web of Science by using the following keywords: type-2 diabetes mellitus (T2DM), first-line and second-line treatment, oral hypoglycemic agents, insulin administration, diet/nutritional therapy, gene and stem cell therapy, and diabetic complications.

RESULTS

The first-line treatment of T2DM includes administering oral hypoglycemic agents (OHAs) and second-line treatment by insulin therapy and some OHAs like Sulfonylurea's (SU). The oral hypoglycemic or oral antidiabetic drugs have the function of lowering glucose in the blood. Insulin therapy is recommended for people with A1C levels > 7.0, and insulin administration is evolved drastically from the syringe, pump, pen, inhalation, insulin jet, and patch. The use of OHAs and insulin therapy during glycemic control has a severe effect on weight gain and other side effects. Hence, diet maintenance (macro and micronutrients) and nutritional therapy guidelines were also reviewed/recommended for safe T2DM management. Besides, the recent progress in molecular approaches that focuses on identifying new targets for T2DM (i.e.) consisting of gene therapy, stem cell therapy, and the modulation of insulin signaling pathways for the regulation of glucose storage and uptake also discussed.

CONCLUSION

The analysis of all these key factors is necessary to develop a potential agent to cure T2DM and suggest that a combination of therapies will pave the way for advanced management of T2DM.

A silver-catalyzed [3 + 3]-annulation cascade of alkynyl alcohols and α,β-unsaturated ketones for the regioselective assembly of chromanes

An unprecedented Ag(i)-catalyzed [3 + 3]-annulation of alkynyl alcohols (5-hexyn-1-ols) and α,β-unsaturated ketones is reported to construct simple to complex chromanes.

Serum- and glucocorticoid-induced kinase drives hepatic insulin resistance by directly inhibiting AMP-activated protein kinase

A hallmark of type 2 diabetes (T2D) is hepatic resistance to insulin's glucose-lowering effects. The serum- and glucocorticoid-regulated family of protein kinases (SGK) is activated downstream of mechanistic target of rapamycin complex 2 (mTORC2) in response to insulin in parallel to AKT. Surprisingly, despite an identical substrate recognition motif to AKT, which drives insulin sensitivity, pathological accumulation of SGK1 drives insulin resistance. Liver-specific Sgk1-knockout (Sgk1Lko) mice display improved glucose tolerance and insulin sensitivity and are protected from hepatic steatosis when fed a high-fat diet. Sgk1 promotes insulin resistance by inactivating AMP-activated protein kinase (AMPK) via phosphorylation on inhibitory site AMPKαSer485/491. We demonstrate that SGK1 is dominant among SGK family kinases in regulation of insulin sensitivity, as Sgk1, Sgk2, and Sgk3 triple-knockout mice have similar increases in hepatic insulin sensitivity. In aggregate, these data suggest that targeting hepatic SGK1 may have therapeutic potential in T2D.

Synthesis of Sugar Diene and Its Pd-Catalyzed Transformation into Chromanes

A route to synthesize 1,2-disubstituted glucals has been developed, which were further converted to substituted chromanes by thermal 6π-electrocyclization in HMPA followed by in situ aromatization. One of the key steps in the synthesis of chromane is metal-free generation of C1-substituted glucal from d-mannose, which was further converted to 1,2-disubstituted glucals by Pd-catalyzed Fujiwara-Moritani reaction with styrenes, acrylates, acrylamide, acrylonitrile, and ethyl vinyl ketone in good yields.

Glucose availability but not changes in pancreatic hormones sensitizes hepatic AMPK activity during nutritional transition in rodents

The cellular energy sensor AMP-activated protein kinase (AMPK) is a metabolic regulator that mediates adaptation to nutritional variations to maintain a proper energy balance in cells. We show here that suckling-weaning and fasting-refeeding transitions in rodents are associated with changes in AMPK activation and the cellular energy state in the liver. These nutritional transitions were characterized by a metabolic switch from lipid to glucose utilization, orchestrated by modifications in glucose levels and the glucagon/insulin ratio in the bloodstream. We therefore investigated the respective roles of glucose and pancreatic hormones on AMPK activation in mouse primary hepatocytes. We found that glucose starvation transiently activates AMPK, whereas changes in glucagon and insulin levels had no impact on AMPK. Challenge of hepatocytes with metformin-induced metabolic stress strengthened both AMPK activation and cellular energy depletion under limited-glucose conditions, whereas neither glucagon nor insulin altered AMPK activation. Although both insulin and glucagon induced AMPKα phosphorylation at its Ser^485/491 residue, they did not affect its activity. Finally, the decrease in cellular ATP levels in response to an energy stress was additionally exacerbated under fasting conditions and by AMPK deficiency in hepatocytes, revealing metabolic inflexibility and emphasizing the importance of AMPK for maintaining hepatic energy charge. Our results suggest that nutritional changes (i.e. glucose availability), rather than the related hormonal changes (i.e. the glucagon/insulin ratio), sensitize AMPK activation to the energetic stress induced by the dietary transition during fasting. This effect is critical for preserving the cellular energy state in the liver.

A Novel Lipidomics-Based Approach to Evaluating the Risk of Clinical Hepatotoxicity Potential of Drugs in 3D Human Microtissues

The importance of adsorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis is expected to grow substantially due to recent failures in detecting severe toxicity issues of new chemical entities during preclinical/clinical development. Traditionally, safety risk assessment studies for humans have been conducted in animals during advanced preclinical or clinical phase of drug development. However, potential drug toxicity in humans now needs to be detected in the drug discovery process as soon as possible without reliance on animal studies. The "omics", such as genomics, proteomics, and metabolomics, have recently entered pharmaceutical research in both drug discovery and drug development, but to the best of our knowledge, no applications in high-throughput safety risk assessment have been attempted so far. This paper reports an innovative method to anticipate adverse drug effects in an early discovery phase based on lipid fingerprints using human three-dimensional microtissues. The risk of clinical hepatotoxicity potential was evaluated for a data set of 22 drugs belonging to five different therapeutic chemical classes and with various drug-induced liver injury effect. The treatment of microtissues with repeated doses of each drug allowed collecting lipid fingerprints for five time points (2, 4, 7, 9, and 11 days), and multivariate statistical analysis was applied to search for correlations with the hepatotoxic effect. The method allowed clustering of the drugs based on their hepatotoxic effect, and the observed lipid impairments for a number of drugs was confirmed by literature sources. Compared to traditional screening methods, here multiple interconnected variables (lipids) are measured simultaneously, providing a snapshot of the cellular status from the lipid perspective at a molecular level. Applied here to hepatotoxicity, the proposed workflow can be applied to several tissues, being tridimensional microtissues from various origins.