CREB1 and ATF1 Negatively Regulate Glutathione Biosynthesis Sensitizing Cells to Oxidative Stress

Citrus flavanone metabolites protect pancreatic β-cells against cholesterol stress through a multi-proteomic mechanism

Citrus flavanones may improve oxidative stress and insulin resistance induced by western diets. However, there is a paucity of studies investigating the change in protein expression levels. This study evaluated the protection and the mechanisms of action of citrus flavanone metabolites, hesperetin 7-glucuronide (H7G) and 3-(4'-hydroxyphenyl) propanoic acid (PA), on pancreatic β-cell function under oxidative stress induced by cholesterol using the global proteomics approach. Cholesterol induced changes in the global proteomic profile in the pancreatic β-cell line Min6. On the other hand, proteomics analysis identified 254 proteins differentially expressed with H7G and 352 with PA treatments, most of them were opposite to the changes induced by cholesterol. Bioinformatics analysis showed that these proteins are implicated in cell functions like cell signaling (insulin signaling, p30MAPK signaling, and others), metabolism (glucokinase and glutathione metabolisms), and inflammation pathways (TNF-α and NF-κB pathways). Also, the results of molecular docking suggest that H7G and PA could bind to putative transcription factors (PPAR-γ, STAT-3, CREB1, NF-κB, NFYA) and cell signaling proteins (IKK, RAS, Pi3K, ERK), which results in changes in protein expression observed. Altogether, these data suggest that the treatment with H7G and PA protects pancreatic β-cells against stress induced by cholesterol through multi-proteomic mechanisms of action.

CREB1 and PPAR-α/γ Pathways in Hepatic Ischemia/Reperfusion: Route for Curcumin to Hepatoprotection

Background

Hepatic ischemia/reperfusion injury is a major problem that can exacerbate complications, particularly in liver transplantations.

Objectives

This study aimed to investigate the cellular mechanisms of ischemia/reperfusion injury and hepatoprotection by curcumin.

Methods

Wistar albino rats were divided into four groups as Control, Sham, I/R, and Cur+I/R. Hepatic ischemia/reperfusion was induced in I/R and Cur+I/R animals, the latter of which was also given 50 mg/kg/day of curcumin for 14 days. Liver aminotransferases and the transcription regulators of inflammation (RelA, IκB, PPAR-α, PPAR-γ, CREB1) were examined along with the histological examination.

Results

Hepatic ischemia/reperfusion was found to disrupt hepatic microstructure and downregulate PPAR-α, PPAR-γ, and CREB1 transcripts. Curcumin supplementation in hepatic ischemia/reperfusion recovered the structural organization and promoted the hepatocyte regeneration while increasing expressions of PPARs and CREB1. RelA and IκB were found unaltered, possibly due to the crosstalk between targeted transcripts by ischemia/reperfusion and curcumin.

Conclusions

In sum, PPAR-α/γ and CREB1 were involved in hepatic ischemia/reperfusion and, moreover, were detected to be stimulated by curcumin. PPAR and CREB pathways were found to provide a route to hepatoprotection for curcumin supplementation as evidenced by the microstructural improvement.

Metabolites and Genes behind Cardiac Metabolic Remodeling in Mice with Type 1 Diabetes Mellitus

Metabolic remodeling is at the heart of diabetic cardiomyopathy. High glycemic fluctuations increase metabolic stress in the type 1 diabetes mellitus (T1DM) heart. There is a lack of understanding on how metabolites and genes affect metabolic remodeling in the T1DM heart. We hypothesize that differential expression of metabolic genes and metabolites synergistically influence metabolic remodeling preceding T1DM cardiomyopathy. To test our hypothesis, we conducted high throughput analysis of hearts from adult male hyperglycemic Ins2^+/− (Akita) and littermate normoglycemic Ins2^+/+ (WT) mice. The Akita mouse is a spontaneous, genetic model of T1DM that develops increased levels of consistent glycemic variability without the off-target cardiotoxic effects present in chemically- induced models of T1DM. After validating the presence of a T1DM phenotype, we conducted metabolomics via LC-MS analysis and genomics via next-generation sequencing in left ventricle tissue from the Akita heart. Ingenuity Pathway Analyses revealed that 108 and 30 metabolic pathways were disrupted within the metabolomics and genomics datasets, respectively. Notably, a comparison between the two analyses showed 15 commonly disrupted pathways, including ketogenesis, ketolysis, cholesterol biosynthesis, acetyl CoA hydrolysis, and fatty acid biosynthesis and beta-oxidation. These identified metabolic pathways predicted by the differential expression of metabolites and genes provide the foundation for understanding metabolic remodeling in the T1DM heart. By limited experiment, we revealed a predicted disruption in the metabolites and genes behind T1DM cardiac metabolic derangement. Future studies targeting these genes and metabolites will unravel novel therapies to prevent/improve metabolic remodeling in the T1DM heart.