Assessing Obesity-Related Adipose Tissue Disease (OrAD) to Improve Precision Medicine for Patients Living With Obesity

sNucConv: A bulk RNA-seq deconvolution method trained on single-nucleus RNA-seq data to estimate cell-type composition of human adipose tissues

Deconvolution algorithms mostly rely on single-cell RNA-sequencing (scRNA-seq) data applied onto bulk RNA-sequencing (bulk RNA-seq) to estimate tissues' cell-type composition, with performance accuracy validated on deposited databases. Adipose tissues' cellular composition is highly variable, and adipocytes can only be captured by single-nucleus RNA-sequencing (snRNA-seq). Here we report the development of sNucConv, a Scaden deep-learning-based deconvolution tool, trained using 5 hSAT and 7 hVAT snRNA-seq-based data corrected by (i) snRNA-seq/bulk RNA-seq highly correlated genes and (ii) individual cell-type regression models. Applying sNucConv on our bulk RNA-seq data resulted in cell-type proportion estimation of 15 and 13 cell types, with accuracy of R = 0.93 (range: 0.76-0.97) and R = 0.95 (range: 0.92-0.98) for hVAT and hSAT, respectively. This performance level was further validated on an independent set of samples (5 hSAT; 5 hVAT). The resulting model was depot specific, reflecting depot differences in gene expression patterns. Jointly, sNucConv provides proof-of-concept for producing validated deconvolution models for tissues un-amenable to scRNA-seq.

Circulating miRNAs Detect High vs Low Visceral Adipose Tissue Inflammation in Patients Living With Obesity

CONTEXT

The severity of visceral adipose tissue (VAT) inflammation in individuals with obesity is thought to signify obesity subphenotype(s) associated with higher cardiometabolic risk. Yet, this tissue is not accessible for direct sampling in the nonsurgical patient.

OBJECTIVE

We hypothesized that circulating miRNAs (circ-miRs) could serve as biomarkers to distinguish human obesity subgroups with high or low extent of VAT inflammation.

METHODS

Discovery and validation cohorts of patients living with obesity undergoing bariatric surgery (n = 35 and 51, respectively) were included. VAT inflammation was classified into low/high based on an expression score derived from the messenger RNA levels of TNFA, IL6, and CCL2 (determined by reverse transcription polymerase chain reaction). Differentially expressed circ-miRs were identified, and their discriminative power to detect low/high VAT inflammation was assessed by receiver operating characteristic-area under the curve (ROC-AUC) analysis.

RESULTS

Fifty three out of 263 circ-miRs (20%) were associated with high-VAT inflammation according to Mann-Whitney analysis in the discovery cohort. Of those, 12 (12/53 = 23%) were differentially expressed according to Deseq2, and 6 significantly discriminated between high- and low-VAT inflammation with ROC-AUC greater than 0.8. Of the resulting 5 circ-miRs that were differentially abundant in all 3 statistical approaches, 3 were unaffected by hemolysis and validated in an independent cohort. Circ-miRs 181b-5p, 1306-3p, and 3138 combined with homeostatic model assessment of insulin resistance (HOMA-IR) exhibited ROC-AUC of 0.951 (95% CI, 0.865-1) and 0.808 (95% CI, 0.654-0.963) in the discovery and validation cohorts, respectively, providing strong discriminative power between participants with low- vs high-VAT inflammation. Predicted target genes of these miRNAs are enriched in pathways of insulin and inflammatory signaling, circadian entrainment, and cellular senescence.

CONCLUSION

Circ-miRs that identify patients with low- vs high-VAT inflammation constitute a putative tool to improve personalized care of patients with obesity.

Visceral adipocyte size links obesity with dysmetabolism more than fibrosis, and both can be estimated by circulating miRNAs

OBJECTIVE

In obesity, adipocyte hypertrophy is detrimental to health, but its' interrelation with fibrosis in the visceral adipose tissue (VAT) depot remains unclear. Because VAT is less accessible via biopsy, biomarkers for VAT quality are needed. The authors hypothesized that VAT adipocyte size and fibrosis are interrelated and can be estimated by circulating microRNAs (circ-miRNAs), contributing to subphenotyping obesity.

METHODS

Adipocyte size and AT fibrosis were estimated in n = 43 participants (BMI ≥ 30 kg/m2 ). Circ-miRNAs were sequenced (Next Generation Sequencing).

RESULTS

Participants with above- versus below-median VAT adipocyte area exhibited metabolic dysfunction but lower total and pericellular fibrosis. VAT adipocyte size remained associated with metabolic dysfunction even when controlling for BMI or VAT fibrosis in the entire cohort, as in matched-pairs subanalyses. Next Generation Sequencing uncovered 22 and 6 circ-miRNAs associated with VAT adipocyte size and fibrosis, respectively, with miRNA-130b-3p common to both analyses. The combination of miRNA-130b-3p + miR-150-5p + high-density lipoprotein cholesterol discriminated among those with large versus small VAT adipocytes (receiver operating characteristic-area under the curve: 0.872 [95% CI: 0.747-0.996]), whereas miRNA-130b-3p + miRNA-15a-5p + high-density lipoprotein cholesterol discriminated among those with low and high fibrosis (receiver operating characteristic-area under the curve: 0.823 [95% CI: 0.676-0.97]).

CONCLUSIONS

These findings suggest that VAT adipocyte size and fibrosis are inversely correlated in obesity and can be estimated by distinct circ-miRNAs, providing a potential tool to subphenotype obesity via a liquid biopsy-like approach to assess VAT health in nonsurgical patients.

Alisol B blocks the development of HFD-induced obesity by triggering the LKB1-AMPK signaling in subcutaneous adipose tissue

As a global epidemic disease, obesity causes dysfunction of glucose and lipid metabolism leading to persistently high morbidity and mortality. Given the difficulty to achieve and maintain weight loss through controlling diet and physical exercise, pharmacotherapy is considered an effective treatment for obesity. This investigation revealed that alisol B, a triterpene monomer isolated from the classical Chinese medicine Alisma orientale (Sam.) Juzep, functioned in suppressing adipogenesis and reducing the mass of subcutaneous adipose tissue, resulting in the reduction of weight gain, and improvements of hyperglycemia, hyperlipidemia, and insulin resistance in HFD-induced obese mice. In consistent to the results, alisol B also significantly inhibited adipocyte differentiation and maturation in vitro. Furthermore, our data revealed that the effects of alisol B on adipogenesis were mediated by LKB1-AMPK signaling pathway. In total, alisol B could be a potential lead compound which contributes to the improvement of obesity-related metabolic disorders.

Towards an adiposity-related disease framework for the diagnosis and management of obesities

Obesity is a complex disease that relapses frequently and associates with multiple complications that comprise a worldwide health priority because of its rising prevalence and association with numerous complications, including metabolic disorders, mechanic pathologies, and cancer, among others. Noteworthy, excess adiposity is accompanied by chronic inflammation, oxidative stress, insulin resistance, and subsequent organ dysfunction. This dysfunctional adipose tissue is initially stored in the visceral depot, overflowing subsequently to produce lipotoxicity in ectopic depots like liver, heart, muscle, and pancreas, among others. People living with obesity need a diagnostic approach that considers an exhaustive pathophysiology and complications assessment. Thus, it is essential to warrant a holistic diagnosis and management that guarantees an adequate health status, and quality of life. The present review summarizes the different complications associated with obesity, at the same time, we aim to fostering a novel framework that enhances a patient-centered approach to obesity management in the precision medicine era.

Parental obesity-induced changes in developmental programming

Many studies support the link between parental obesity and the predisposition to develop adult-onset metabolic syndromes that include obesity, high blood pressure, dyslipidemia, insulin resistance, and diabetes in the offspring. As the prevalence of obesity increases in persons of childbearing age, so does metabolic syndrome in their descendants. Understanding how parental obesity alters metabolic programs in the progeny, predisposing them to adult-onset metabolic syndrome, is key to breaking this cycle. This review explores the basis for altered metabolism of offspring exposed to overnutrition by focusing on critical developmental processes influenced by parental obesity. We draw from human and animal model studies, highlighting the adaptations in metabolism that occur during normal pregnancy that become maladaptive with obesity. We describe essential phases of development impacted by parental obesity that contribute to long-term alterations in metabolism in the offspring. These encompass gamete formation, placentation, adipogenesis, pancreas development, and development of brain appetite control circuits. Parental obesity alters the developmental programming of these organs in part by inducing epigenetic changes with long-term consequences on metabolism. While exposure to parental obesity during any of these phases is sufficient to alter long-term metabolism, offspring often experience multiple exposures throughout their development. These insults accumulate to increase further the susceptibility of the offspring to the obesogenic environments of modern society.