Skeletal muscle functions as an endocrine organ. Exosomes, small vesicles containing mRNAs,
miRNAs, and proteins, are secreted from muscle cells and facilitate cell-to-cell communication.
Our recent work found greater exosome release from oxidative compared to glycolytic muscle.
Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a key driver
of mitochondrial biogenesis, a characteristic of oxidative muscle. It was hypothesized that PGC1α regulates exosome biogenesis and secretion in skeletal muscle. The purpose of this study is to
determine if PGC-1α regulates skeletal muscle exosome biogenesis and secretion. On day 4 of
differentiation, human primary myotubes from vastus lateralis biopsies from lean donors (BMI <
25.0 kg/m2) were exposed to adenovirus encoding human PGC-1α or GFP control. On day 6 of
differentiation, culture media was replaced with exosome-free media. On day 8, cells were
collected for mRNA and protein analysis, and culture media was collected for exosome isolation.
Overexpression of PGC-1α increases regulators of exosome biogenesis in the endosomal sorting
complexes required for transport (ESCRT) pathway: Alix (CON: 1.0 ± 0.2 vs. PGC-1α: 7.6 ±
3.8), TSG-101 (CON: 1.0 ± 0.1 vs. PGC-1α: 7.3 ± 2.1), CD63 (CON: 1.0 ± 0.17 vs. PGC-1α: 3.7
± 0.4), Clathrin (CON: 1.0 ± 0.2 vs. PGC-1α: 11.6 ± 2.5), and the secretion pathway: Rab27b
(CON: 1.0 ± 0.3 vs. PGC-1α: 3.2 ± 0.3), STAM (CON: 1.0 ± 0.3 vs. PGC-1α: 7.3 ± 0.6), and
VTA1 (CON: 1.0 ± 0.1 vs. PGC-1α: 7.3 ± 2.4). Exosome count and total extracellular vesicle
count were not significantly different from control. Overexpression of PGC-1α increases gene
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expression of regulators of exosome biogenesis and secretion in human primary myotubes. In the
future, in vitro studies assessing exosomal content from PGC-1 OE cells as well as in vivo
effects of PGC-1 OE on exosome production and release should be investigated to further
understand the role PGC-1 plays in exosome secretion.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12739643 |
| Date | 30 July 2020 |
| Creators | Derek M Middleton (9187400) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/The_Role_of_PGC-1a_Overexperssion_in_Skeletal_Muscle_Exosome_Biogenesis_and_Secretion/12739643 |
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