Mechanism-Based Biomarker Prediction for Low-Grade Inflammation in Liver and Adipose Tissue

Multi-study feasibility analysis on a composite biomarker of inflammatory resilience to quantify the effects of energy restriction on low-grade inflammation in overweight and obese individuals

PURPOSE

Assessing the health impacts of nutritional interventions in metabolically compromised but otherwise healthy individuals is challenging, necessitating sensitive tools. Phenotypic flexibility offers an innovative way to measure homeostatic capacity during challenge tests. A composite biomarker of inflammatory resilience has proven useful in evaluating the health benefits of whole-grain wheat interventions in overweight and obese individuals. Expanding this method to other dietary interventions to combat low-grade inflammation is essential.

METHODS

This study investigated the feasibility of a composite biomarker of inflammatory resilience through secondary analysis of samples from two independent energy restriction (ER) trials, Bellyfat (NCT02194504) and Nutritech (NCT01684917). In these trials, fasting and postprandial inflammation was analysed using a variety of markers. Four composite biomarker models were developed on the basis of postprandial inflammatory marker responses via the 'health space' model method. These models were statistically evaluated for their sensitivity in detecting the effects of 12 weeks of ER.

RESULTS

The minimal composite biomarkers, consisting of IL-6, IL-8, IL-10, and TNF-α, lacked the ability to detect postprandial intervention effects in both ER trials. However, in the Nutritech study, the extended, endothelial, and optimized composite biomarkers of inflammatory resilience displayed significant responses to the ER (all P < 0.005). In the latter 3 models, a reduction in the inflammatory score was correlated with a reduction in BMI and body fat percentage.

CONCLUSION

This study underscores the feasibility of employing a composite biomarker of inflammatory resilience to evaluate ER interventions. Further validation in additional nutritional intervention studies is necessary. Once validated, this composite biomarker could offer a novel approach for assessing low-grade inflammation and phenotypic flexibility.

Integrative analysis of miRNAs and proteins in plasma extracellular vesicles of patients with familial hypercholesterolemia

BACKGROUND AND AIMS

Familial Hypercholesterolemia (FH) is a monogenic disease that leads to early-onset atherosclerosis. Causative mutations in FH-related genes are found in 60-80 % of patients, while epigenetic factors may contribute to mutation-negative cases. This study analyzed miRNAs and proteins from plasma-derived extracellular vesicles (EVs) of FH patients to explore their contribution in FH diagnosis.

METHODS

Clinical and laboratory data were obtained from 54 FH patients and 38 normolipidemic individuals. FH-related gene variants were identified using exon-targeted gene sequencing. Plasma EVs miRNome and proteome were analysed using small RNA sequencing and liquid chromatography/mass spectrometry.

RESULTS

Thirteen FH patients carried LDLR deleterious variants (MD group), while 41 did not (non-MD group). Over 2000 miRNAs were detected in plasma EVs, with miR-122-5p higher in FH patients compared to controls, and miR-21-5p higher in the MD group than in the non-MD group (p < 0.05). Proteomic analysis identified 300 proteins with 18 out of 38 proteins more abundant in EVs than in total plasma. Eighteen EVs-derived proteins had differential abundance in FH patients compared to control group (p < 0.05). EV levels of miR-122-5p, miR-21-5p and 12 proteins were correlated with serum lipids (p < 0.05). The integrative analysis between dysregulated miRNAs (miR-122-5p and miR-21-5p) and altered proteins (APOD, APOF, MBL2 and MASP1) from EVs identified several common pathways involved in cholesterol metabolism.

CONCLUSION

Co-regulation of plasma EVs miR-122-5p, miR-21-5p, APOD, APOF, MBL2 and MASP1 and their correlation with serum lipids suggest their involvement in impaired cholesterol metabolism and may be useful as biomarkers of FH severity.

Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions

Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.

Comparison of Plasma Exosome Proteomes Between Obese and Non-Obese Patients with Type 2 Diabetes Mellitus

PURPOSE

Obesity is considered a promoter of type 2 diabetes mellitus (T2DM). However, the underlying mechanism remains unclear. This study aimed to identify plasma exosome differentially expressed proteins (DEPs) that are potentially involved in the development of obesity-related T2DM.

METHODS

Exosomes were isolated from the plasma of obese and non-obese T2DM patients (n = 10 for each group). A label-free quantitative mass spectrometry analysis was applied to identify plasma exosome DEPs in obese patients compared with non-obese patients, followed by bioinformatics analysis including GO annotation, KEGG analysis, subcellular localization prediction, transcription factor analysis, and protein-protein interaction (PPI) prediction.

RESULTS

We identified 2 significantly upregulated proteins (C9 and PON1) and 5 significantly downregulated proteins (HPX, A1BG, CFHR1, ANG, and CALM) in obese patients compared with those in non-obese patients. KEGG analysis demonstrated that the insulin signaling pathway was one of the pathways that significantly correlated with the DEPs. The DEPs were primarily localized in the extracellular space (5 out of 7). HMG-box and NF-Y beta might regulate the transcription of the DEPs. C9, PON1, HPX, and CFHR1 were present in the PPI network.

CONCLUSION

The plasma exosome DEPs are potentially responsible for the development of obesity-related T2DM possibly through the insulin signaling pathway and the interaction with other proteins. Our study may guide future research direction toward the pathogenesis of obesity-related T2DM.

Non-Cytokine Protein Profile of the Mesenchymal Stem Cell Secretome That Regulates the Androgen Production Pathway

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in reproductive-aged women, and it typically involves elevated androgen levels. Recently, it has been reported that human bone marrow mesenchymal stem cells (hBM-MSCs) can regulate androgen synthesis pathways. However, the details of the mechanism are still unclear. hBM-MSC-derived secreted factors (the secretome) are promising sources of cell-based therapy as they consist of various types of proteins. It is thus important to know which proteins interact with disease-implicated biomolecules. This work aimed to investigate which secretome components contain the key factor that inhibits testosterone synthesis. In this study, we fractionated hBM-MSC-conditioned media into three fractions based on their molecular weights and found that, of the three fractions, one had the ability to inhibit the androgen-producing genes efficiently. We also analyzed the components of this fraction and established a protein profile of the hBM-MSC secretome, which was shown to inhibit androgen synthesis. Our study describes a set of protein components present in the hBM-MSC secretome that can be used therapeutically to treat PCOS by regulating androgen production for the first time.

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.