Circulating mRNA and miRNA signatures used as predictive markers of lifestyle modification outcomes in pediatric obesity management

The response to lifestyle modification (LSM) in children with obesity is variable and difficult to predict. AIM: A systematic search for molecular markers to predict outcomes of LSM in pediatric obesity management. PATIENTS AND METHODS: Out of 240 children with obesity (BMI>97%) recruited to a prospective 'multi-OMICS' study granted by ESPE Research Unit, 159 subjects (age 8-17 yrs, median 12.8 yrs; 45% females) finished twelve-months (between visits V0-V12) of LSM at three clinical centers (Poland, Turkey, Italy). Four of >180 baseline (V0, before LSM) clinical and laboratory features (sex, age, severity of obesity at V0, steroid metabolome) were used to select 50 representatives for RNA-seq analysis. We searched for circulating mRNA & miRNA capable of establishing the link with positive response to LSM defined by a decrease in z-score BMI (delta z-score BMI V12-V0<0, Responders/RS). First, the candidate gene approach with previously documented STAT3, CORO1C, SERPINH1, MVP, ITGB5 (upregulated in obesity), PCM1, SIRT1, EEF1G, PTEN and RPS2 (down-regulated in obesity) hub genes was applied. The pairwise ratios of transcripts per million (TPM)s of these genes were tested for statistical significance between RS (n=31) and non-RS (n=19) groups. Secondly, the TPM expression values of 2,129 miRNAs and 33,246 RPL13A-normalized mRNAs were compared between RS and non-RS to get a list of putative significant genes (p<0.05; the Welch t-test). Enrichr, a web-based tool (http://amp.pharm.mssm.edu/Enrichr), was used for analysing gene sets. RESULTS: Expression values for 909 mRNA and 24 miRNA genes were significantly different between RS vs non-RS. For example, STAT3/PTEN, CORO1C/PTEN, MVP/PTEN; miRNA-10a, miRNA-122, miRNA-127, miRNA-502, miRNA-210 were significantly higher and SIRT1/PTEN, EEF1G/PTEN, RPS2/PTEN, miRNA-27a were lower comparing RS vs. non-RS (p= 0.009, 0.022, 0.030, 0.048, 0.029, 0.045, 0.035, 0.020, 0.047, 0.04, 0.039, 0.029, respectively). Several pathways, including "Vitamin B6 metabolism" and "Insulin receptor signaling", were enriched in our differentially expressed mRNA (p<0.001): PNPO, PHOSPHO2, PDXP, PSAT1 were up-regulated in RS vs. non-RS. "Leptin signaling pathway WP2034" were enriched in STAT3 and PTEN (p<0.0001). CONCLUSIONS: The role of the balance between STAT3 and PTEN in LSM was discovered. The importance of previously described miRNA markers (miRNA-122, miRNA-127, miRNA-27a) related to adipogenesis risk, insulin resistance, hepatic fat reduction, PPAR-γ expression were confirmed. A combination of the previously reported V0 Leptin feature together with STAT3/PTEN and miRNA-27a levels showed promising predictive results. Our findings not only showed the predictive molecular markers but also pointed to their role in personalization of therapeutic management.