Marit Hjorth

Natural products obtained from marine organisms continue to be a rich source of novel structural architecture and of importance in drug discovery, medicine, and health. However, the success of such endeavors depends on the exact structural elucidation and access to sufficient material, often by stereoselective total synthesis, of the isolated natural product of interest. (−)-Mucosin (1), a fatty acid derivative, previously presumed to contain a rare cis-bicyclo[4.3.0]non-3-ene moiety, has since been shown to be the trans-congener. Analytically, the fused bicyclic ring system in (−)-1 constitutes a particular challenge in order to establish its relative and absolute stereochemistry. Herein, data from biological evaluations, NMR and molecular modeling studies of (−)-1 are presented. An overview of the synthetic strategies enabling the exact structural elucidation of (−)-mucosin (1) is also presented.

Extracellular vesicles induced by exercise have emerged as potential mediators of tissue crosstalk. Extracellular vesicles and their cargo miRNAs have been linked to dysglycemia and obesity in animal models, but their role in humans is unclear. Aim The aim of the study was to characterize the miRNA content in plasma extracellular vesicle isolates after acute and long‐term exercise and to study associations between extracellular vesicle miRNAs, mRNA expression in skeletal muscle and adipose tissue, and cardiometabolic risk factors. Methods Sedentary men with or without dysglycemia and overweight underwent an acute bicycle test and a 12‐week exercise intervention with extensive metabolic phenotyping. Gene expression in m. vastus lateralis and subcutaneous adipose tissue was measured with RNA sequencing. Extracellular vesicles were purified from plasma with membrane affinity columns or size exclusion chromatography. Results Extracellular vesicle miRNA profiling revealed a transient increase in the number of miRNAs after acute exercise. We identified miRNAs, such as miR‐652‐3p, that were associated to insulin sensitivity and adiposity. By performing explorative association analyses, we identified two miRNAs, miR‐32‐5p and miR‐339‐3p, that were strongly correlated to an adipose tissue macrophage signature. Conclusion Numerous miRNAs in plasma extracellular vesicle isolates were increased by exercise, and several miRNAs correlated to insulin sensitivity and adiposity. Our findings warrant future studies to characterize exercise‐induced extracellular vesicles and cargo miRNA to clarify where exercise‐induced extracellular vesicles originate from, and to determine whether they influence metabolic health or exercise adaptation.