Project Details
Projekt
Investigating mechano-protective mechanisms in human skeletal muscle
Subject Area
Cell Biology
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 388932620
Resistance exercise but not endurance exercise increases muscle mass in humans. This circumstance is regulated by distinct and specific signalling pathways either activated by mechanical or metabolical stimulation. Although mechanical strain adapts skeletal muscle it also threatens sarcomeric integrity and may induce muscle damage. Therefore, mechanoprotective mechanisms constantly regulate maintenance, degradation and disposal of mechanically damaged sarcomeric proteins. However, metabolical and mechanical stimuli induced by resistance- and endurance exercise interfere on the level of skeletal muscle signalling which may also affect mechanoprotective systems. We aim to analyse the regulation of mechanoprotective regulators in human skeletal muscle exposed to acute resistance exercise with and without metabolical pre-stimulation. Therefore, we will apply acute and intense RE on healthy human subjects at two separate occasions, one time preceded by endurance exercise. Skeletal muscle biopsies will be collected at rest and within acute time courses until 24hours after resistance exercise. Here, we will analyse phosphorylation, localization and the expression of mechanoprotective regulators. We hypothesize that endurance exercise induces a changed metabolic environment in skeletal muscle which activates kinases and mechanoprotective regulators that modify the mechanoprotective response compared to resistance exercise-stimulation alone. In skeletal muscle samples of M. vastus lateralis we will analyse structural damage of the z-disks via immunofluorescence to estimate the impact of mechanical stress. The expression and localization of key components of the CASA machinery (FLNc, BAG3, and HSPB8) that operate at sites of FLNc disposal will be analysed.The phosphorylation of small heat shock proteins HSPB1, HSPB5 and HSP90 as well their regulating kinases will be determined separately in type I and type II fibers as these have a distinct z-disc architecture and are distinctly prone towards mechanically-induced muscle damage. We will further determine the expression and phosphorylation of CASA-inhibiting kinase STK38 to determine its central role for the regulation of BAG3-dependent proteostasis. A detailed phosphoproteomic analysis will enable us to determine relevant signalling pathways and their target proteins under resistance- and endurance training. We will also analyse PI3K/AKT/mTOR signalling as this regulates FLNc phosphorylation and induces protein synthesis after acute RE. The proposed work will reveal the acute time course and dynamic of molecular mechanisms essential for mechanical stress protection in human skeletal muscle with a changed metabolic environment. This will be of high relevance for our understanding of molecular mechanoprotective mechanisms in human skeletal muscle and later for clinical purposes.
DFG Programme
Research Units
Subproject of
FOR 2743:
Mechanical Stress Protection
