scholarly journals MiR-17 family-mediated regulation of Pknox1 influences hepatic steatosis and insulin signaling

2018 ◽  
Vol 22 (12) ◽  
pp. 6167-6175 ◽  
Author(s):  
Dan Ye ◽  
Guohua Lou ◽  
Tianbao Zhang ◽  
Fengqin Dong ◽  
Yanning Liu
Author(s):  
Jukka Hintikka ◽  
Sanna Lensu ◽  
Elina Mäkinen ◽  
Sira Karvinen ◽  
Marjaana Honkanen ◽  
...  

We have shown that prebiotic xylo-oligosaccharides (XOS) increased beneficial gut microbiota (GM) and prevented high fat diet-induced hepatic steatosis, but the mechanisms associated with these effects are not clear. We studied whether XOS affects adipose tissue inflammation and insulin signaling, and whether the GM and fecal metabolome explain associated patterns. XOS was supplemented or not with high (HFD) or low (LFD) fat diet for 12 weeks in male Wistar rats (n = 10/group). Previously analyzed GM and fecal metabolites were biclustered to reduce data dimensionality and identify interpretable groups of co-occurring genera and metabolites. Based on our findings, biclustering provides a useful algorithmic method for capturing such joint signatures. On the HFD, XOS-supplemented rats showed lower number of adipose tissue crown-like structures, increased phosphorylation of AKT in liver and adipose tissue as well as lower expression of hepatic miRNAs. XOS-supplemented rats had more fecal glycine and less hypoxanthine, isovalerate, branched chain amino acids and aromatic amino acids. Several bacterial genera were associated with the metabolic signatures. In conclusion, the beneficial effects of XOS on hepatic steatosis involved decreased adipose tissue inflammation and likely improved insulin signaling, which were further associated with fecal metabolites and GM.


2012 ◽  
Vol 84 (11) ◽  
pp. 1501-1510 ◽  
Author(s):  
Hyejeong Jwa ◽  
Youngshim Choi ◽  
Ui-Hyun Park ◽  
Soo-Jong Um ◽  
Seung Kew Yoon ◽  
...  

2020 ◽  
Vol 21 (21) ◽  
pp. 7815
Author(s):  
Tomoko Okuyama ◽  
Jun Shirakawa ◽  
Kazuki Tajima ◽  
Yoko Ino ◽  
Heidrun Vethe ◽  
...  

Abnormal hepatic insulin signaling is a cause or consequence of hepatic steatosis. DPP-4 inhibitors might be protective against fatty liver. We previously reported that the systemic inhibition of insulin receptor (IR) and IGF-1 receptor (IGF1R) by the administration of OSI-906 (linsitinib), a dual IR/IGF1R inhibitor, induced glucose intolerance, hepatic steatosis, and lipoatrophy in mice. In the present study, we investigated the effects of a DPP-4 inhibitor, linagliptin, on hepatic steatosis in OSI-906-treated mice. Unlike high-fat diet-induced hepatic steatosis, OSI-906-induced hepatic steatosis is not characterized by elevations in inflammatory responses or oxidative stress levels. Linagliptin improved OSI-906-induced hepatic steatosis via an insulin-signaling-independent pathway, without altering glucose levels, free fatty acid levels, gluconeogenic gene expressions in the liver, or visceral fat atrophy. Hepatic quantitative proteomic and phosphoproteomic analyses revealed that perilipin-2 (PLIN2), major urinary protein 20 (MUP20), cytochrome P450 2b10 (CYP2B10), and nicotinamide N-methyltransferase (NNMT) are possibly involved in the process of the amelioration of hepatic steatosis by linagliptin. Thus, linagliptin improved hepatic steatosis induced by IR and IGF1R inhibition via a previously unknown mechanism that did not involve gluconeogenesis, lipogenesis, or inflammation, suggesting the non-canonical actions of DPP-4 inhibitors in the treatment of hepatic steatosis under insulin-resistant conditions.


2011 ◽  
Vol 300 (5) ◽  
pp. E779-E789 ◽  
Author(s):  
R. Krishnapuram ◽  
E. J. Dhurandhar ◽  
O. Dubuisson ◽  
H. Kirk-Ballard ◽  
S. Bajpeyi ◽  
...  

Drugs that improve chronic hyperglycemia independently of insulin signaling or reduction of adiposity or dietary fat intake may be highly desirable. Ad36, a human adenovirus, promotes glucose uptake in vitro independently of adiposity or proximal insulin signaling. We tested the ability of Ad36 to improve glycemic control in vivo and determined if the natural Ad36 infection in humans is associated with better glycemic control. C57BL/6J mice fed a chow diet or made diabetic with a high-fat (HF) diet were mock infected or infected with Ad36 or adenovirus Ad2 as a control for infection. Postinfection (pi), systemic glycemic control, hepatic lipid content, and cell signaling in tissues pertinent to glucose metabolism were determined. Next, sera of 1,507 adults and children were screened for Ad36 antibodies as an indicator of past natural infection. In chow-fed mice, Ad36 significantly improved glycemic control for 12 wk pi. In HF-fed mice, Ad36 improved glycemic control and hepatic steatosis up to 20 wk pi. In adipose tissue (AT), skeletal muscle (SM), and liver, Ad36 upregulated distal insulin signaling without recruiting the proximal insulin signaling. Cell signaling suggested that Ad36 increases AT and SM glucose uptake and reduces hepatic glucose release. In humans, Ad36 infection predicted better glycemic control and lower hepatic lipid content independently of age, sex, or adiposity. We conclude that Ad36 offers a novel tool to understand the pathways to improve hyperglycemia and hepatic steatosis independently of proximal insulin signaling, and despite a HF diet. This metabolic engineering by Ad36 appears relevant to humans for developing more practical and effective antidiabetic approaches.


Author(s):  
Xiaoming Ma ◽  
Xing Xue ◽  
Jingxin Zhang ◽  
Shuang Liang ◽  
Chunfang Xu ◽  
...  

Abstract Background and Aims Liver expressed antimicrobial peptide 2 (LEAP2) is recently identified as a regulator in energy metabolism. This study aims to 1) investigate the role of leap2 in hepatic steatosis in C57BL/6 mice; 2) evaluate the association between circulating LEAP2 levels and liver fat contents in a hospital based case-control study. Methods The rodent experiment: western blotting and qPCR were performed to evaluate leap2 levels, lipid metabolism pathways and insulin signaling. shRNA was used to knockdown leap2. The clinical study: commercial ELISA kits were used to measure circulating LEAP2 levels (validated by western blotting). Liver fat content was estimated using MRI-derived proton density fat fraction and FibroScan-derived controlled attenuation parameter. Results The rodent experiment found the hepatic expression and secreted levels of leap2 were increased in mice with diet-induced steatosis. Leap2 knockdown ameliorated steatosis via lipolytic/lipogenic pathway and improved insulin sensitivity via IRS/AKT signaling. The clinical study reported increased circulating levels of LEAP2 in the subjects with steatosis. Moreover, LEAP2 correlated positively with age, body mass index, waist-to-hip ratio, liver fat content, fasting insulin and HOMA-IR, whereas inversely with acyl-ghrelin. Furthermore, the circulating levels of LEAP2 are dependent on liver fat content, acyl-ghrelin and fasting glucose. Lastly, circulating LEAP2 is an independent predictor of NAFLD. Conclusions The study suggests LEAP2 is associated with hepatic steatosis, which may involve lipolytic/lipogenic pathway and insulin signaling.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Weiqin Chen ◽  
Hongyi Zhou ◽  
Pradip Saha ◽  
Luge Li ◽  
Lawrence Chan

Bscl2–/– mice recapitulate many of the major metabolic manifestations in Berardinelli-Seip Congenital Lipodystrophy type 2 (BSCL2) individuals, including lipodystrophy, hepatomegly, hepatic steatosis and insulin resistance. The mechanisms that underlie hepatic steatosis and insulin resistance in Bscl2–/– mice are poorly understood. To address this issue, we performed hyperinsulinemic-euglycemic clamp on Bscl2–/– and wild-type mice after an overnight (16-h) fast, and found that Bscl2–/– actually displayed increased hepatic insulin sensitivity. Interestingly, liver in Bscl2–/– mice after a short term (4-h) fast had impaired acute insulin signaling, a defect that disappeared after a 16-h fast. Notably, fasting dependent hepatic insulin signaling in Bscl2–/– mice was not associated with liver diacylglyceride and ceramide contents, but could be attributable in part to the expression of hepatic insulin signaling receptor and substrates. Meanwhile, increased de novo lipogenesis and decreased β-oxidation led to severe hepatic steatosis in fed or short fasted Bscl2–/– mice while liver lipid accumulation and metabolism in Bscl2–/– mice was markedly impacted by prolonged fasting. Furthermore, mice with liver-specific inactivation of Bscl2 manifested no hepatic steatosis even under high fat diet, suggesting Bscl2 does not play a cell autonomous role in regulating liver lipid homeostasis. Overall, our results offered new insights into the metabolic adaptations of liver in response to fasting and uncovered a novel fasting-dependent regulation of hepatic insulin signaling in a mouse model of human BSCL2.


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