The effect of quercetin on adipogenesis, lipolysis, and apoptosis in 3T3-L1 adipocytes: The role of SIRT1 pathways

Background

Lipotoxicity, caused by adipocyte triglyceride over-accumulation, contributes to obesity-related comorbidities such as hypertension, type 2 diabetes, coronary heart disease, respiratory dysfunction, and osteoarthritis. This study focuses on determining how sirtuin-1 (SIRT-1) mediates quercetin's (QCT) effect on 3T3-L1 adipocytes. Key aspects of this study include preventing adipogenesis, inducing lipolysis, and stimulating adipocyte apoptosis.

Methods

3T3-L1 adipocytes underwent treatment with varying QCT doses, lipopolysaccharide (LPS), and the SIRT-1 inhibitor EX-527, followed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide [MTT] assay for cell viability assessment. Furthermore, quantitative real-time polymerase chain reaction measured mRNA expression levels of adipogenesis markers (fatty acid synthase [FASN] and peroxisome proliferator-activated receptor gamma [PPARγ]), lipolysis markers (adipose triglyceride lipase [ATGL] and hormone-sensitive lipase [HSL]), and apoptosis markers (B-cell lymphoma2 [Bcl-2], Bcl-2 Associated -X-protein [BAX] and Caspase-3).

Results

The data showed that LPS + QCT significantly reduced cell viability in a dose- and time-dependent manner, unaffected by LPS + QCT + EX-527. Treatment with LPS + QCT did not affect FASN and PPARγ expression but significantly increased ATGL and HSL mRNA expression compared with LPS alone. Interestingly, EX-527 reversed the effects of LPS + QCT on lipogenesis and lipolysis markers completely. QCT enhanced apoptosis in a SIRT-1 independent pattern.

Conclusion

The data suggest that QCT suppresses adipogenesis while increasing lipolysis via SIRT-1. However, QCT's effects on apoptosis appear to be independent of SIRT-1. These findings provide further evidence for QCT's effects on adipocytes, particularly its interaction with SIRT-1.

Psychometric responsiveness of the health-related quality of life questionnaire (HeartQoL-P) in the Iranian post-myocardial infarction patients

Background

Cardiovascular diseases (CVD) as a most frequent and costly NCDs account for about 17.3 million annual deaths worldwide. About 80% of these deaths are taking place in low and middle income countries (LMIC). The survivors may experience severe disabling consequences with extensive impacts on their quality of life. The HeartQoL is a relatively new scale to measure health-related quality of life in CVD patients and was validated for use in other languages. Main aim of the present study was to validate the HeartQoL for Persian speaking populations.

Design and methods

In this cross-sectional study the participants were 557 admitted patients with acute myocardial infarction (AMI) across three specialized hospitals in Tabriz, North West of Iran from Sep 2014 to Feb 2015. Translation back-translation procedures were applied to prepare the Persian version of the HeartQol (HeartQoL-P) and the content validity of the scale was evaluated by an expert panel of 10 academic staff. Construct validity was assessed by exploratory and confirmatory factor analyses. The internal consistency was assessed based on the numeric value of Cronbach’s alpha and sensitivity of the measure according to the ceiling and floor effect’s values.

Results

The two-factor structure of the HeartQoL-P was supported by the confirmatory factor analysis’ outputs and good internal consistency measures (total score α = 0.94) (physical subscale (10 items) α = 0.95) and emotional subscale (4items) α = 0.80)). No ceiling and floor effects were observed for the overall HeartQol-P’s score.

Conclusion

The findings supported the HeartQoL-P usability as a valid instrument in studies on the Iranian or other Persian speaking patients.

Fine-tunable plasma nano-machining for fabrication of 3D hollow nanostructures: SERS application

Novel processing sequences for the fabrication of artificial nanostructures are in high demand for various applications. In this paper, we report on a fine-tunable nano-machining technique for the fabrication of 3D hollow nanostructures. This technique originates from redeposition effects occurring during Ar dry etching of nano-patterns. Different geometries of honeycomb, double ring, nanotube, cone and crescent arrays have been successfully fabricated from various metals such as Au, Ag, Pt and Ti. The geometrical parameters of the 3D hollow nanostructures can be straightforwardly controlled by tuning the discharge plasma pressure and power. The structure and morphology of nanostructures are probed using atomic force microscopy (AFM), scanning electron microscopy (SEM), optical emission spectroscopy (OES) and energy dispersive x-ray spectroscopy (EDS). Finally, a Ag nanotube array was assayed for application in surface enhanced Raman spectroscopy (SERS), resulting in an enhancement factor (EF) of 5.5 × 10⁵, as an experimental validity proof consistent with the presented simulation framework. Furthermore, it was found that the theoretical EF value for the honeycomb array is in the order of 10⁷, a hundred times greater than that found in nanotube array.

Increased formation and degradation of malondialdehyde-modified proteins under conditions of peroxidative stress

The effect of increased in vivo lipid peroxidation on excretion of the main urinary metabolites of malondialdehyde (MDA) was investigated. peroxidative stress in the form of vitamin E deficiency or the administration of iron nitrilotriacetate or carbon tetrachloride was imposed on rats fed an MDA-free diet. Significant increases were observed in excretion of the lysine-MDA adduct epsilon-propenal lysine, its N-acetyl ester, and free MDA. Under the conditions imposed, the increments in excretion of the lysine adducts reflect increased peroxidative modification of tissue proteins in vivo. These adducts also were found to be the main forms of MDA excreted in human urine. Reacting 14C-bovine serum albumin (BSA) with MDA resulted in its accelerated proteolysis in vitro by soluble enzyme preparations derived from human erythrocytes and rat liver mitochondria. The increments observed were similar to those reported for the hydrolysis of BSA following its exposure to hydroxyl radicals. The results show that lipid peroxidation in vivo results in peroxidative damage to tissue proteins and indicate that such proteins are subject to an accelerated rate of proteolysis.

A comparative evaluation of thiobarbituric acid methods for the determination of malondialdehyde in biological materials

A comparative evaluation was made of the conventional spectrophotometric procedure and three published high performance liquid chromatographic (HPLC) procedures for the determination of malondialdehyde (MDA) as the thiobarbituric acid (TBA) derivative when applied to liver, fish meal, serum, and urine. Except for urine, spectrophotometric analysis overestimated MDA content. Purification of the TBA-MDA complex obtained from liver and fish meal on reverse phase cartridges was found to entail a loss of complex bound to residual peptides in the trichloracetic acid (TCA) extract. Mincing as opposed to homogenizing liver samples led to a doubling of values for MDA content. Hexanal was a major TBA reactant, in addition to MDA, in all the samples. Acid hydrolysis and heat were necessary for the release of MDA bound to the amino groups of proteins and other amino compounds. Methods for free MDA have limited application to biological materials except short term in vitro preparations such as peroxidizing microsomes, in which free MDA accumulates. On the basis of these and other observations, a modified HPLC procedure for the determination of MDA as the TBA-MDA complex is proposed.