Endocrine Abstracts

Metabolic dysfunction in skeletal muscle disturbs both the critical vascular network and fundamental muscle fibre architecture. However, the molecular drivers during metabolic stress responsible for transmitting these events remain poorly defined. To reveal these we mapped changes in the spatial proteome occurring as a result of impaired metabolic health. We exposed male and female mice (C57/BL6J) to high fat diets and conducted digital spatial profiling (NanoString GEOMX) on skeletal muscle comparing it to standard chow controls(n=12). Male (n=6) and female mice (n=6) were fed ±high fat diet (60% kcals from fat) for 8 weeks. Skeletal muscle tissue (tibialis anterior) was collected and sectioned for spatial profiling. Samples were also cryosectioned for immunofluorescence with the muscle marker Desmin and endothelial cell marker CD31, to highlight the vascular networks within the tissues. Digital spatial profiling within HFD muscle defined regions demonstrated reduced Desmin immunoreactivity (control diet 55,0000±5430.0 vs high fat 15,1533 ± 0.15 P<0.01) and elevated CD31 expression (control diet 7.99 ± 0.15 vs high fat 10.04 ± 0.15 P<0.05), markers of tissue stress and cellular maladaptation. We find that increased expression of proinflammatory markers (CD68 P<0.001, CD39 P<0.05, and CD40 P<0.01) was identified in areas of depleted Desmin in high fat diet samples compared to control. Our data suggest a dietary driven relationship between the spatial abundance of the sarcomere protein Desmin and the influx of inflammatory mediators. This supports the notion that pro-inflammatory events underpin the muscle metabolic dysfunction associated with chronic non-communicative diseases such as type 2 diabetes, metabolic ill health, and chronic obstructive pulmonary disorder.