Understanding the response to endurance exercise using a systems biology approach: combining blood metabolomics, transcriptomics and miRNomics in horses

Endurance exercise in horses requires adaptive processes involving physiological, biochemical, and cognitive-behavioral responses in an attempt to regain homeostasis. We hypothesized that the identification of the relationships between blood metabolome, transcriptome, and miRNome during endurance exercise in horses could provide significant insights into the molecular response to endurance exercise. For this reason, the serum metabolome and whole-blood transcriptome and miRNome data were obtained from ten horses before and after a 160 km endurance competition. We obtained a global regulatory network based on 11 unique metabolites, 263 metabolic genes and 5 miRNAs whose expression was significantly altered at T1 (post-endurance competition) relative to T0 (baseline, pre-endurance competition). This network provided new insights into the cross talk between the distinct molecular pathways (e.g. energy and oxygen sensing, oxidative stress, and inflammation) that were not detectable when analyzing single metabolites or transcripts alone. Single metabolites and transcripts were carrying out multiple roles and thus sharing several biochemical pathways. Using a regulatory impact factor metric analysis, this regulatory network was further confirmed at the transcription factor and miRNA levels. In an extended cohort of 31 independent animals, multiple factor analysis confirmed the strong associations between lactate, methylene derivatives, miR-21-5p, miR-16-5p, let-7 family and genes that coded proteins involved in metabolic reactions primarily related to energy, ubiquitin proteasome and lipopolysaccharide immune responses after the endurance competition. Multiple factor analysis also identified potential biomarkers at T0 for an increased likelihood for failure to finish an endurance competition. To the best of our knowledge, the present study is the first to provide a comprehensive and integrated overview of the metabolome, transcriptome, and miRNome co-regulatory networks that may have a key role in regulating the metabolic and immune response to endurance exercise in horses. El ejercicio de resistencia en caballos requiere procesos adaptativos que involucren respuestas fisiológicas, bioquímicas y cognitivo-conductuales en un intento de recuperar la homeostasis. Nuestra hipótesis fue que la identificación de las relaciones entre el metaboloma de la sangre, el transcriptoma y miRNome durante el ejercicio de resistencia en caballos podría proporcionar información importante sobre la respuesta molecular al ejercicio de resistencia. Por esta razón, el metaboloma sérico y los datos de transcriptoma de sangre completa y miRNome se obtuvieron de diez caballos antes y después de una competición de resistencia de 160 km. L'exercici de resistència en cavalls requereix processos adaptatius que involucrin respostes fisiològiques, bioquímiques i cognitiu-conductuals en un intent de recuperar l'homeòstasi. La nostra hipòtesi va ser que la identificació de les relacions entre el metaboloma de la sang, el transcriptoma i miRNome durant l'exercici de resistència en cavalls podria proporcionar informació important sobre la resposta molecular a l'exercici de resistència. Per aquesta raó, el metaboloma sèric i les dades de transcriptoma de sang completa i miRNome es van obtenir de deu cavalls abans i després d'una competició de resistència de 160 km.