Author(s): BENEDETTO ROBAINA, M., SPILLANE, P.2, ANSDELL, P.2, HICKS, K.2, BOST, J.3, RAMACHANDRAN, B.4, BUTKA, L.5, JAMESON, T.1, MADEN-WILKINSON, T.1, ORANGE, S.T.1, Institution: EMLES BIOVENTURES, Country: UNITED KINGDOM, Abstract-ID: 1155

INTRODUCTION:
During acute maximal exercise, skeletal muscle and other secretory organs release small proteins, known as exerkines, into the systemic circulation, facilitating inter-organ crosstalk and mediating some of the multisystemic benefits of exercise. Dermal interstitial fluid (dISF) is a biological fluid surrounding skin cells, which is rich in diverse analytes, similar to blood composition. As such, dISF may enable minimally invasive access to exerkines, with potential to support scalable monitoring of proteomic responses to acute exercise. Therefore, the aims are to (i) determine whether proteins can be detected and quantified in dISF, (ii) explore whether acute exercise induces measurable changes in the dISF proteome, and (iii) characterise changes in exercise-responsive biological pathways in the dISF proteome.
METHODS:
Three healthy adult males (32.3 ± 1.2 years) completed a maximal incremental treadmill exercise test. Approximately 10μL of dISF was collected from the forearm, pre- and post-exercise using a microneedle-based collection system. Proteins were analysed using label-free data-independent acquisition (DIA) mass spectrometry and classified as exercise-responsive if they showed a ≥1.2-fold change with consistent direction of change across all participants.
RESULTS:
Median protein concentration per dISF sample was 27.5 mg/mL. A total of 1,350 proteins were identified across all the samples, ranging from high abundance plasma proteins (e.g., albumin) to low abundance signalling proteins (e.g., MMP-9). Known exerkines, including SPARC, FSTL1, and FSTL3, were detected. 150 proteins increased and 39 decreased in abundance post-exercise. Upregulated proteins were enriched for pathways related to stress and detoxification, metal-binding and redox regulation, and metabolic and translational processes, whereas downregulated proteins were enriched for pathways associated with extracellular matrix organisation and remodelling, and cell-matrix interaction.
CONCLUSION:
Acute maximal exercise was associated with measurable changes in the dISF proteome. These findings indicate that dISF enables detection and quantification of exercise-responsive proteins and captures biologically relevant molecular signatures following exercise.