Blockade of High-Fat Diet Proteomic Phenotypes Using Exercise as Prevention or Treatment

Automated preparation of plasma lipids, metabolites, and proteins for LC/MS-based analysis of a high-fat diet in mice

Blood plasma is one of the most commonly analyzed and easily accessible biological samples. Here, we describe an automated liquid-liquid extraction (LLE) platform that generates accurate, precise, and reproducible samples for metabolomic, lipidomic, and proteomic analyses from a single aliquot of plasma while minimizing hands-on time and avoiding contamination from plasticware. We applied mass spectrometry to examine the metabolome, lipidome, and proteome of 90 plasma samples to determine the effects of age, time of day, and a high-fat diet in mice. From 25 μL of mouse plasma, we identified 907 lipid species from 16 different lipid classes and subclasses, 233 polar metabolites, and 344 proteins. We found that the high-fat diet induced only mild changes in the polar metabolome, upregulated Apolipoproteins, and induced substantial shifts in the lipidome, including a significant increase in arachidonic acid (AA) and a decrease in eicosapentaenoic acid (EPA) content across all lipid classes.

Moderate-intensity constant or high-intensity interval training? Metabolic effects on candidates to undergo bariatric surgery

BACKGROUND & AIMS

Bariatric surgery is highly effective against obesity. Pre-surgical exercise programs are recommended to prepare the candidate physically and metabolically for surgery-related rapid weight loss. However, the ideal exercise prescription in this population is unknown. This study aimed to compare the metabolic effects of moderate-intensity constant (MICT) vs. a high-intensity interval training (HIIT) program in candidates to undergo bariatric surgery.

METHODS AND RESULTS

Twenty-five candidates (22 women) to undergo sleeve gastrectomy aged from 18 to 60 years old were recruited. At baseline, we measured body composition, physical activity levels, grip strength, and aerobic capacity. Further, we assessed metabolic function through glycemia and insulinemia (both fasting and after oral glucose tolerance test (OGTT)), homeostatic model assessment for insulin resistance (HOMA-IR), lipid profile, glycated haemoglobin (HbA1c), transaminases, fibroblast growth factor 21 (FGF21), growth differentiation factor 15 (GDF15), apelin, and adiponectin. Afterward, participants were randomized into MICT (n = 14) or HIIT (n = 11). Both training programs consisted of 10 sessions (2-3 times/week, 30 min per session) distributed during 4 weeks before the surgery. After this, all outcomes were measured again at the end of the training programs and 1 month after the surgery (follow-up). A mixed effect with Tukey's post-hoc analysis was performed to compare values at baseline vs. post-training vs. postsurgical follow-up. Both training programs increased aerobic capacity after training (p < 0.05), but only after MICT these changes were kept at follow-up (p < 0.05). However, only MICT decreased fat mass and increased total muscle mass and physical activity levels (p < 0.05). Metabolically, MICT decreased insulinemia after OGTT (p < 0.05), whereas HIIT increased adiponectin after training and GDF15 at follow-up (both p < 0.05).

CONCLUSIONS

Both MICT and HIIT conferred benefits in candidates to undergo bariatric surgery, however, several of those effects were program-specific, suggesting that exercise intensity should be considered when preparing these patients. Future studies should explore the potential benefits of prescribing MICT or HIIT in a customized fashion depending on a pretraining screening, along with possible summatory effects by combining these two exercise programs (MICT + HIIT).

CLINICAL TRIAL REGISTRATION

International Traditional Medicine Clinical Trial Registry, N° ISRCTN42273422.

The Efficacy of Risk Factor Modification Compared to NAD+ Repletion in Diastolic Heart Failure

Heart failure (HF) with left ventricular diastolic dysfunction is a growing global concern. This study evaluated myocardial oxidized nicotinamide adenine dinucleotide (NAD+) levels in human systolic and diastolic HF and in a murine model of HF with preserved ejection fraction, exploring NAD+ repletion as therapy. We quantified myocardial NAD+ and nicotinamide phosphoribosyltransferase levels, assessing restoration with nicotinamide riboside (NR). Findings show significant NAD+ and nicotinamide phosphoribosyltransferase depletion in human diastolic HF myocardium, but NR successfully restored NAD+ levels. In murine HF with preserved ejection fraction, NR as preventive and therapeutic intervention improved metabolic and antioxidant profiles. This study underscores NAD+ repletion's potential in diastolic HF management.

Integrated liver and serum proteomics uncover sexual dimorphism and alteration of several immune response proteins in an aging Werner syndrome mouse model

Werner syndrome (WS) is a progeroid disorder caused by mutations in a protein containing both a DNA exonuclease and DNA helicase domains. Previous studies indicated that males lacking the helicase domain of the Wrn protein orthologue exhibited hepatic transcriptomic and metabolic alterations. In this study, we used a label-free liquid chromatography-tandem mass spectrometry approach to uncover proteins abundance associated with specific biological processes that differed depending on the age (four or ten months) and/or the genotype (wild type or Wrn mutant) in the serum and liver of mice. Principal component analysis of the proteomic data from both serum and hepatic tissue revealed a sexual dimorphism regardless of the age and the genotype of the mice. Moreover, although all Wrn mutant mice exhibited fatty liver by the age of ten months, a significant age and genotype dependent enrichment of proteins involved in lipid and fatty acid metabolic processes were uncovered only in males. Also, a genotype dependent increase in serum oxidant detoxification processes was observed in the serum of Wrn mutant males. Despite these sexual differences, several aspects of the immune system were affected in both females and males. Finally, an increase of specific immunoglobulin molecules was common in the liver and serum of both older Wrn mutant females and males. Such results suggest that specific immunoglobulin variants maybe associated with fatty liver progression in WS.

Effect of dapagliflozin on proteomics and metabolomics of serum from patients with type 2 diabetes

BACKGROUND

Sodium-glucose co-transporter 2 (SGLT2) inhibitors reduced the risk of cardiovascular and renal outcomes in patients with type 2 diabetes (T2D), but the underlying mechanism has not been well elucidated. The circulating levels of proteins and metabolites reflect the overall state of the human body. This study aimed to evaluate the effect of dapagliflozin on the proteome and metabolome in patients with newly diagnosed T2D.

METHODS

A total of 57 newly diagnosed T2D patients were enrolled, and received 12 weeks of dapagliflozin treatment (10 mg/d, AstraZeneca). Serum proteome and metabolome were investigated at the baseline and after dapagliflozin treatment.

RESULTS

Dapagliflozin significantly decreased HbA1c, BMI, and HOMA-IR in T2D patients (all p < 0.01). Multivariate models indicated clear separations of proteomics and metabolomics data between the baseline and after dapagliflozin treatment. A total of 38 differentially abundant proteins including 23 increased and 15 decreased proteins, and 35 differentially abundant metabolites including 17 increased and 18 decreased metabolites, were identified. In addition to influencing glucose metabolism (glycolysis/gluconeogenesis and pentose phosphate pathway), dapagliflozin significantly increased sex hormone-binding globulin, transferrin receptor protein 1, disintegrin, and metalloprotease-like decysin-1 and apolipoprotein A-IV levels, and decreased complement C3, fibronectin, afamin, attractin, xanthine, and uric acid levels.

CONCLUSIONS

The circulating proteome and metabolome in newly diagnosed T2D patients were significantly changed after dapagliflozin treatment. These changes in proteins and metabolites might be associated with the beneficial effect of dapagliflozin on cardiovascular and renal outcomes.

Transcriptome Analysis of Protection by Dendrobium Nobile Alkaloids (DNLA) against Chronic Alcoholic Liver Injury in Mice

Objective: To investigate the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) against chronic alcoholic liver injury. C57BL/6J mice were fed with the Lieber−DeCarli alcohol diet to induce chronic alcoholic liver injury. DNLA (20 mg/kg/day) was gavaged along with the alcohol diet for 28 days. Liver injury was evaluated by serum enzymes. Triglyceride levels, histopathology, and transcriptome changes were examined by RNA-Seq and qPCR. DNLA decreased serum triglyceride levels in mice receiving alcohol. Hepatocyte degeneration and steatosis were ameliorated by DNLA, as evidenced by H&E and Oil-red O staining. DNLA brought the alcohol-induced aberrant gene expression pattern towards normal. Alcohol induced 787 differentially expressed genes (padj < 0.01). DNLA induced 280 differentially expressed genes to a much less extent. Ingenuity pathway analysis showed that DNLA ameliorated alcohol-induced oxidative stress and xenobiotic metabolism disruption. qPCR verified that DNLA alleviated over-activation of Cyp2a4, Cyp2b10, and Abcc4; attenuated oxidative stress (Hmox1, Gstm3, Nupr1), reduced the expression of Nrf2 genes (Nqo1, Gclc, Vldlr); and rescued some metabolic genes (Insig1, Xbp1, Socs3, Slc10a2). In conclusion, DNLA was effective against alcohol-induced fatty liver disease, and the protection may be attributed to alleviated oxidative stress and restored metabolism homeostasis, probably through modulating nuclear receptor CAR-, PXR-, and Nrf2-mediated gene expression pathways.

Comparative Proteomic Analysis of Liver Tissues and Serum in db/db Mice

Background and Aims: Non-alcoholic fatty liver disease (NAFLD) affects one-quarter of individuals worldwide. Liver biopsy, as the current reliable method for NAFLD evaluation, causes low patient acceptance because of the nature of invasive sampling. Therefore, sensitive non-invasive serum biomarkers are urgently needed. Results: The serum gene ontology (GO) classification and Kyoto encyclopedia of genes and genomes (KEGG) analysis revealed the DEPs enriched in pathways including JAK-STAT and FoxO. GO analysis indicated that serum DEPs were mainly involved in the cellular process, metabolic process, response to stimulus, and biological regulation. Hepatic proteomic KEGG analysis revealed the DEPs were mainly enriched in the PPAR signaling pathway, retinol metabolism, glycine, serine, and threonine metabolism, fatty acid elongation, biosynthesis of unsaturated fatty acids, glutathione metabolism, and steroid hormone biosynthesis. GO analysis revealed that DEPs predominantly participated in cellular, biological regulation, multicellular organismal, localization, signaling, multi-organism, and immune system processes. Protein-protein interaction (PPI) implied diverse clusters of the DEPs. Besides, the paralleled changes of the common upregulated and downregulated DEPs existed in both the liver and serum were validated in the mRNA expression of NRP1, MUP3, SERPINA1E, ALPL, and ALDOB as observed in our proteomic screening. Methods: We conducted hepatic and serum proteomic analysis based on the leptin-receptor-deficient mouse (db/db), a well-established diabetic mouse model with overt obesity and NAFLD. The results show differentially expressed proteins (DEPs) in hepatic and serum proteomic analysis. A parallel reaction monitor (PRM) confirmed the authenticity of the selected DEPs. Conclusion: These results are supposed to offer sensitive non-invasive serum biomarkers for diabetes and NAFLD.

Clinical Interest of Serum Alpha-2 Macroglobulin, Apolipoprotein A1, and Haptoglobin in Patients with Non-Alcoholic Fatty Liver Disease, with and without Type 2 Diabetes, before or during COVID-19

In patients with non-alcoholic fatty liver disease (NAFLD) with or without type 2 diabetes mellitus (T2DM), alpha-2 macroglobulin (A2M), apolipoprotein A1 (ApoA1), and haptoglobin are associated with the risk of liver fibrosis, inflammation (NASH), and COVID-19. We assessed if these associations were worsened by T2DM after adjustment by age, sex, obesity, and COVID-19. Three datasets were used: the “Control Population”, which enabled standardization of protein serum levels according to age and sex (N = 27,382); the “NAFLD-Biopsy” cohort for associations with liver features (N = 926); and the USA “NAFLD-Serum” cohort for protein kinetics before and during COVID-19 (N = 421,021). The impact of T2DM was assessed by comparing regression curves adjusted by age, sex, and obesity for the liver features in “NAFLD-Biopsy”, and before and during COVID-19 pandemic peaks in “NAFLD-Serum”. Patients with NAFLD without T2DM, compared with the values of controls, had increased A2M, decreased ApoA1, and increased haptoglobin serum levels. In patients with both NAFLD and T2DM, these significant mean differences were magnified, and even more during the COVID-19 pandemic in comparison with the year 2019 (all p < 0.001), with a maximum ApoA1 decrease of 0.21 g/L in women, and a maximum haptoglobin increase of 0.17 g/L in men. In conclusion, T2DM is associated with abnormal levels of A2M, ApoA1, and haptoglobin independently of NAFLD, age, sex, obesity, and COVID-19.

Integrated Liver and Plasma Proteomics in Obese Mice Reveals Complex Metabolic Regulation

Obesity leads to the development of nonalcoholic fatty liver disease (NAFLD) and associated alterations to the plasma proteome. To elucidate the underlying changes associated with obesity, we performed liquid chromatography-tandem mass spectrometry in the liver and plasma of obese leptin-deficient ob/ob mice and integrated these data with publicly available transcriptomic and proteomic datasets of obesity and metabolic diseases in preclinical and clinical cohorts. We quantified 7173 and 555 proteins in the liver and plasma proteomes, respectively. The abundance of proteins related to fatty acid metabolism were increased, alongside peroxisomal proliferation in ob/ob liver. Putatively secreted proteins and the secretory machinery were also dysregulated in the liver, which was mirrored by a substantial alteration of the plasma proteome. Greater than 50% of the plasma proteins were differentially regulated, including NAFLD biomarkers, lipoproteins, the 20S proteasome, and the complement and coagulation cascades of the immune system. Integration of the liver and plasma proteomes identified proteins that were concomitantly regulated in the liver and plasma in obesity, suggesting that the systemic abundance of these plasma proteins is regulated by secretion from the liver. Many of these proteins are systemically regulated during type 2 diabetes and/or NAFLD in humans, indicating the clinical importance of liver-plasma cross talk and the relevance of our investigations in ob/ob mice. Together, these analyses yield a comprehensive insight into obesity and provide an extensive resource for obesity research in a prevailing model organism.