Lipid-induced alteration in retinoic acid signaling leads to mitochondrial dysfunction in HepG2 and Huh7 cells.

A surfeit of mitochondrial reactive oxygen species (ROS) and inflammation serve as obligatory mediators of lipid-associated hepatocellular maladies. While retinoid homeostasis is essential in restoring systemic energy balance, its role in hepatic mitochondrial function remains elusive. The role of lecithin-retinol acyltransferase (LRAT) in maintenance of retinoid homeostasis is appreciated earlier; however, its role in modulating retinoic acid (RA) bioavailability upon lipid-imposition is unexplored. We identified LRAT overexpression in high-fat diet (HFD)-fed rats and palmitate-treated hepatoma cells. Elevation in LRAT expression depletes RA production and deregulates RA signaling. This altered RA metabolism enhances fat accumulation, accompanied by inflammation that leads to impaired mitochondrial function through enhanced ROS generation. Hence, LRAT inhibition could be a novel approach preventing lipid-induced mitochondrial dysfunction in hepatoma cells.

Dual PPARα/γ agonist saroglitazar improves liver histopathology and biochemistry in experimental NASH models.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are common clinico-pathological conditions that affect millions of patients worldwide. In this study, the efficacy of saroglitazar, a novel PPARα/γ agonist, was assessed in models of NAFLD/NASH. METHODS & RESULTS: HepG2 cells treated with palmitic acid (PA;0.75 mM) showed decreased expression of various antioxidant biomarkers (SOD1, SOD2, glutathione peroxidase and catalase) and increased expression of inflammatory markers (TNFα, IL1ß and IL6). These effects were blocked by saroglitazar, pioglitazone and fenofibrate (all tested at 10µM concentration). Furthermore, these agents reversed PA-mediated changes in mitochondrial dysfunction, ATP production, NFkB phosphorylation and stellate cell activation in HepG2 and HepG2-LX2 Coculture studies. In mice with choline-deficient high-fat diet-induced NASH, saroglitazar reduced hepatic steatosis, inflammation, ballooning and prevented development of fibrosis. It also reduced serum alanine aminotransferase, aspartate aminotransferase and expression of inflammatory and fibrosis biomarkers. In this model, the reduction in the overall NAFLD activity score by saroglitazar (3 mg/kg) was significantly more prominent than pioglitazone (25 mg/kg) and fenofibrate (100 mg/kg). Pioglitazone and fenofibrate did not show any improvement in steatosis, but partially improved inflammation and liver function. Antifibrotic effect of saroglitazar (4 mg/kg) was also observed in carbon tetrachloride-induced fibrosis model. CONCLUSIONS: Saroglitazar, a dual PPARα/γ agonist with predominant PPARα activity, shows an overall improvement in NASH. The effects of saroglitazar appear better than pure PPARα agonist, fenofibrate and PPARγ agonist pioglitazone.

Iron Regulates Cellular Proliferation by Enhancing the Expression of Glucose Transporter GLUT3 in the Liver.

Iron is often accumulated in the liver during pathological conditions such as cirrhosis and cancer. Elevated expression of glucose transporters GLUT1 and GLUT3 is associated with reduced overall survival in patients with hepatocellular carcinoma. However, it is not known whether iron can regulate glucose transporters and contribute to tumor proliferation. In the present study, we found that treatment of human liver cell line HepG2 with ferric ammonium citrate (FAC) resulted in a significant upregulation of GLUT3 mRNA and protein in a dose-dependent manner. Similarly, iron accumulation in mice fed with high dietary iron as well as in mice injected intraperitoneally with iron dextran enhanced the GLUT3 expression drastically in the liver. We demonstrated that iron-induced hepatic GLUT3 upregulation is mediated by the LKB1/AMPK/CREB1 pathway, and this activation was reversed when treated with iron chelator deferiprone. In addition, inhibition of GLUT3 using siRNA prevented iron-mediated increase in the expression of cell cycle markers and cellular hyperproliferation. Furthermore, exogenous sodium beta-hydroxybutyrate treatment prevented iron-mediated hepatic GLUT3 activation both in vitro and in vivo. Together, these results underscore the importance of iron, AMPK, CREB1 and GLUT3 pathways in cell proliferation and highlight the therapeutic potential of sodium beta-hydroxybutyrate in hepatocellular carcinoma with high GLUT3 expression.

Seedpod extracts of Wrightia tinctoria shows significant anti-inflammatory effects in HepG2 and RAW-264.7cell lines.

W. tinctoria, an Indian herb Indrajao, has significant therapeutic potential. While studies have highlighted the anti-inflammatory potential of the leaves and bark of this plant, similar efficacy of the seed-pods remains unexplored. We demonstrate significant anti-inflammatory effects of the hexane fraction (Fr-B) of ethyl acetate extract of the seedpods in reducing lipopolysaccharide and palmitate mediated inflammation in RAW264.7 macrophages and HepG2 cells. GC-MS and NMR profiling of Fr-B revealed the existence of hexadecanoic acid, ethyl hexadecanoate, 9,12-octadecanoic acid, 9,12,15-octadecatrienoic acid, 9,12,15-octadecatrienoic acid ethyl ester, ethyl linoleate and octadecanoic acid ethyl esters.

The IRONy in Athletic Performance.

Iron is an essential micronutrient for athletes, intricately linked to their performance, by regulating cellular respiration and metabolism. Impaired iron levels in the body can significantly hinder athletic performance. The increased demand for iron due to exercise, coupled with potential dietary iron insufficiencies, particularly among endurance athletes, amplifies the risk of iron deficiency. Moreover, prolonged exercise can impact iron absorption, utilization, storage, and overall iron concentrations in an athlete. On the contrary, iron overload may initially lead to enhanced performance; however, chronic excess iron intake or underlying genetic conditions can lead to detrimental health consequences and may negatively impact athletic performance. Excess iron induces oxidative damage, not only compromising muscle function and recovery, but also affecting various tissues and organs in the body. This narrative review delineates the complex relationship between exercise and iron metabolism, and its profound effects on athletic performance. The article also provides guidance on managing iron intake through dietary adjustments, oral iron supplementation for performance enhancement in cases of deficiency, and strategies for addressing iron overload in athletes. Current research is focused on augmenting iron absorption by standardizing the route of administration while minimizing side effects. Additionally, there is ongoing work to identify inhibitors and activators that affect iron absorption, aiming to optimize the body's iron levels from dietary sources, supplements, and chelators. In summary, by refining the athletic diet, considering the timing and dosage of iron supplements for deficiency, and implementing chelation therapies for iron overload, we can effectively enhance athletic performance and overall well-being.