Browsing by Author "Kalupahana, Nishan S. (TTU)"
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Item An integrative transcriptomic approach to identify depot differences in genes and microRNAs in adipose tissues from high fat fed mice(2018) Wijayatunga, Nadeeja N. (TTU); Pahlavani, Mandana (TTU); Kalupahana, Nishan S. (TTU); Kottapalli, Kameswara Rao (TTU); Gunaratne, Preethi H.; Coarfa, Cristian; Ramalingam, Latha (TTU); Moustaid-Moussa, Naima (TTU)Obesity contributes to metabolic disorders such as diabetes and cardiovascular disease. Characterization of differences between the main adipose tissue depots, white (WAT) [including subcutaneous (SAT) and visceral adipose tissue (VAT)] and brown adipose tissue (BAT) helps to identify their roles in obesity. Thus, we studied depot-specific differences in whole transcriptome and miRNA profiles of SAT, VAT and BAT from high fat diet (HFD/45% of calories from fat) fed mice using RNA sequencing and small RNA-Seq. Using quantitative real-time polymerase chain reaction, we validated depot-specific differences in endoplasmic reticulum (ER) stress related genes and miRNAs using mice fed a HFD vs. low fat diet (LFD/10% of calories from fat). According to the transcriptomic analysis, lipogenesis, adipogenesis, inflammation, endoplasmic reticulum (ER) stress and unfolded protein response (UPR) were higher in VAT compared to BAT, whereas energy expenditure, fatty acid oxidation and oxidative phosphorylation were higher in BAT than in VAT of the HFD fed mice. In contrast to BAT, ER stress marker genes were significantly upregulated in VAT of HFD fed mice than the LFD fed mice. For the first time, we report depot specific differences in ER stress related miRNAs including; downregulation of miR-125b-5p, upregulation miR-143-3p, and miR-222-3p in VAT following HFD and upregulation of miR-30c-2-3p only in BAT following a HFD in mice than the LFD mice. In conclusion, HFD differentially regulates miRNAs and genes in different adipose depots with significant induction of genes related to lipogenesis, adipogenesis, inflammation, ER stress, and UPR in WAT compared to BAT.Item Angiotensin II Increases Endoplasmic Reticulum Stress in Adipose Tissue and Adipocytes(2019) Menikdiwela, Kalhara R. (TTU); Ramalingam, Latha (TTU); Allen, London (TTU); Scoggin, Shane (TTU); Kalupahana, Nishan S. (TTU); Moustaid-Moussa, Naima (TTU)The Renin Angiotensin System (RAS), a key regulator of blood pressure has been linked to metabolic disorders. We have previously reported that adipose overexpression of angiotensinogen in mice (Agt-Tg) induces obesity, in part mediated by adipose tissue inflammation, through yet unidentified mechanisms. Hence, we hypothesize that adipose tissue enrichment of angiotensinogen leads to activation of inflammatory cascades and endoplasmic reticulum (ER) stress, thereby, contributing to obesity. We used wild type (Wt), Agt-Tg and Agt-knockout (KO) mice along with 3T3-L1 and human adipocytes treated with RAS, ER stress and inflammation inhibitors. ER stress and pro-inflammation markers were significantly higher in Agt-Tg compared to Wt mice and captopril significantly reduced their expression. Furthermore, in vitro treatment with Ang II significantly induced ER stress and inflammation, whereas angiotensin II receptor inhibitor, telmisartan reduced RAS effects. Moreover, miR-30 family had significantly lower expression in Agt-Tg group. MiR-708-5p and -143-3p were upregulated when RAS was overexpressed, and RAS antagonists reduced miR-143-3p and -708-5p in both mouse adipose tissue and adipocytes. Activation of RAS by Ang II treatment, increased inflammation and ER stress in adipocytes mainly via AT1 receptor, possibly mediated by miR-30 family, -708-5p and/or -143-3p. Hence, RAS and mediating microRNAs could be used as potential targets to reduce RAS induced obesity and related comorbid diseases.Item Anti-Inflammatory Mechanisms of Curcumin and Its Metabolites in White Adipose Tissue and Cultured Adipocytes(2024) Islam, Tariful (TTU); Scoggin, Shane (TTU); Gong, Xiaoxia (TTU); Zabet-Moghaddam, Masoud (TTU); Kalupahana, Nishan S. (TTU); Moustaid-Moussa, Naima (TTU)The plant-derived polyphenol curcumin alleviates the inflammatory and metabolic effects of obesity, in part, by reducing adipose tissue inflammation. We hypothesized that the benefits of curcumin supplementation on diet-induced obesity and systemic inflammation in mice occur through downregulation of white adipose tissue (WAT) inflammation. The hypothesis was tested in adipose tissue from high-fat diet-induced obese mice supplemented with or without curcumin and in 3T3-L1 adipocytes treated with or without curcumin. Male B6 mice were fed a high-fat diet (HFD, 45% kcal fat) with or without 0.4% (w/w) curcumin supplementation (HFC). Metabolic changes in these mice have been previously reported. Here, we determined the serum levels of the curcumin metabolites tetrahydrocurcumin (THC) and curcumin-O-glucuronide (COG) using mass spectrometry. Moreover, we determined interleukin 6 (IL-6) levels and proteomic changes in LPS-stimulated 3T3-L1 adipocytes treated with or without curcumin by using immunoassays and mass spectrometry, respectively, to gain further insight into any altered processes. We detected both curcumin metabolites, THC and COG, in serum samples from the curcumin-fed mice. Both curcumin and its metabolites reduced LPS-induced adipocyte IL-6 secretion and mRNA levels. Proteomic analyses indicated that curcumin upregulated EIF2 and mTOR signaling pathways. Overall, curcumin exerted anti-inflammatory effects in adipocytes, in part by reducing IL-6, and these effects may be linked to the upregulation of the mTOR signaling pathway, warranting additional mechanistic studies on the effects of curcumin and its metabolites on metabolic health.Item Eicosapentaenoic acid improves hepatic metabolism and reduces inflammation independent of obesity in high-fat-fed mice and in HepG2 cells(2019) Albracht-Schulte, Kembra (TTU); Gonzalez, Samantha (TTU); Jackson, Abigail (TTU); Wilson, Savanna (TTU); Ramalingam, Latha (TTU); Kalupahana, Nishan S. (TTU); Moustaid-Moussa, Naima (TTU)The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide, concurrent with increased obesity. Thus, there is urgent need for research that can lead to effective NAFLD prevention/treatment strategies. Omega-3 polyunsaturated fatty acids (n-3 PUFAs), including eicosapentaenoic acid (EPA), improve inflammation-and dyslipidemia-related metabolic disorders; however, mechanisms mediating the benefits of n-3 PUFAs in NAFLD treatment are less understood. We previously reported that EPA reversed obesity-induced hepatic steatosis in high-fat (HF)-fed B6 mice. Utilizing a combination of biochemical analyses of liver tissues from HF and HF-EPA-fed mice and a series of in vitro studies in tumor necrosis factor-alpha (TNF-α)-stimulated HepG2 cells, we dissect the mechanistic effects of EPA in reducing hepatic steatosis, including the role of EPA-targeted microRNAs (miRNA). With EPA, hepatic lipid metabolism was improved in HF-EPA mice, as indicated by decreased protein and messenger RNA (mRNA) levels of fatty acid synthase (FASN) and acetyl-CoA carboxylase (Acaca) gene, and increased mRNA levels for the peroxisome proliferator activated receptor-α (Pparα), and carnitine palmitoyltransferase (Cpt) 1a and 2 genes in the HF-EPA mice. Additionally, inflammation was reduced, as shown by decreased tumor necrosis factor-alpha (Tnfα) gene expression. Accordingly, EPA also significantly reduced FASN and ACACA mRNAs in human HepG2 cells. Glycolysis, estimated by extracellular acidification rate, was significantly reduced in HepG2 cells treated with EPA vs. vehicle. Furthermore, we identified several miRNAs that are regulated by EPA in mouse liver, including miR-19b-3p, miR-21a-5p, and others, which target lipid metabolism and inflammatory pathways. In conclusion, our findings provide novel mechanistic evidence for beneficial effects of EPA in NAFLD, through the identification of specific genes and miRNAs, which may be further exploited as future NAFLD therapies.Item Role of microRNA 690 in Mediating Angiotensin II Effects on Inflammation and Endoplasmic Reticulum Stress(2020) Menikdiwela, Kalhara R. (TTU); Ramalingam, Latha (TTU); Abbas, Mostafa M.; Bensmail, Halima; Scoggin, Shane (TTU); Kalupahana, Nishan S. (TTU); Palat, Asha; Gunaratne, Preethi; Moustaid-Moussa, Naima (TTU)Overactivation of the renin-angiotensin system (RAS) during obesity disrupts adipocyte metabolic homeostasis and induces endoplasmic reticulum (ER) stress and inflammation; however, underlying mechanisms are not well known. We propose that overexpression of angiotensinogen (Agt), the precursor protein of RAS in adipose tissue or treatment of adipocytes with Angiotensin II (Ang II), RAS bioactive hormone, alters specific microRNAs (miRNA), that target ER stress and inflammation leading to adipocyte dysfunction. Epididymal white adipose tissue (WAT) from B6 wild type (Wt) and transgenic male mice overexpressing Agt (Agt-Tg) in adipose tissue and adipocytes treated with Ang II were used. Small RNA sequencing and microarray in WAT identified differentially expressed miRNAs and genes, out of which miR-690 and mitogen-activated protein kinase kinase 3 (MAP2K3) were validated as significantly up- and down-regulated, respectively, in Agt-Tg, and in Ang II-treated adipocytes compared to respective controls. Additionally, the direct regulatory role of miR-690 on MAP2K3 was confirmed using mimic, inhibitors and dual-luciferase reporter assay. Downstream protein targets of MAP2K3 which include p38, NF-κB, IL-6 and CHOP were all reduced. These results indicate a critical post-transcriptional role for miR-690 in inflammation and ER stress. In conclusion, miR-690 plays a protective function and could be a useful target to reduce obesity.Item Sex-Dependent Effects of Eicosapentaenoic Acid on Hepatic Steatosis in UCP1 Knockout Mice(2021) Albracht-Schulte, Kembra (TTU); Wilson, Savanna (TTU); Johnson, Paige (TTU); Pahlavani, Mandana (TTU); Ramalingam, Latha (TTU); Goonapienuwala, Bimba (TTU); Kalupahana, Nishan S. (TTU); Festuccia, William T.; Scoggin, Shane (TTU); Kahathuduwa, Chanaka N. (TTUHSC); Moustaid-Moussa, Naima (TTU)Visceral obesity may be a driving factor in nonalcoholic fatty liver disease (NAFLD) development. Previous studies have shown that the omega-3 polyunsaturated fatty acid, eicosapentaenoic acid (EPA), ameliorates obesity in high-fat (HF) fed male, C57Bl/6 mice at thermoneutral conditions, independent of uncoupling protein 1 (UCP1). Our goals herein were to investigate sex-dependent mechanisms of EPA in the livers of wild type (WT) and UCP1 knockout (KO) male and female mice fed a HF diet (45% kcal fat; WT-HF, KO-HF) with or without supplementation of 36 g/kg EPA (WT-EPA, KO-EPA). KO significantly increased body weight in males, with no significant reductions with EPA in the WT or KO groups. In females, there were no significant differences in body weight among KO groups and no effects of EPA. In males, liver TGs were significantly higher in the KO-HF group and reduced with EPA, which was not observed in females. Accordingly, gene and protein markers of mitochondrial oxidation, peroxisomal biogenesis and oxidation, as well as metabolic futile cycles were sex-dependently impacted by KO and EPA supplementation. These findings suggest a genotypic difference in response to dietary EPA supplementation on the livers of male and female mice with diet-induced obesity and housed at thermoneutrality.