Skip to main content
2024 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Womens Health

Women's Health - Poster Session E

Poster L23 - The roles of Estrogen and Secretory Carrier Membrane Proteins (SCAMPs) in Myogenesis

Saturday, October 26, 2024
10:00 AM - 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Sarcopenia, or the loss of muscle quality and function with aging, disproportionately impacts women compared to men, with a steep decline in muscle mass and function, leading to a higher rate of morbidity and mortality. This steep decline in muscle function in women is attributed to the loss of estrogen with menopause. Through the utilization of different estrogen receptors (ERs), estrogen can lead to changes in gene expression of downstream signaling pathways in various tissues, including skeletal muscle. Estrogens can modulate signaling through a genomic pathway utilizing ligand-based receptors (ERα, ERβ), and a non-genomic pathway utilizing G-protein coupled estrogen receptor (GPER1). To modulate gene expression using the genomic pathways, estrogen receptors (ERα and ERβ) must bind to DNA sequences (Estrogen Response Elements, EREs) that have a high affinity for them.

SCAMPs (Secretory Carrier Membrane Proteins) are a family of integral membrane proteins within the intracellular transport pathway that regulates the trafficking of molecular components to and from the cell surface. Skeletal muscle regeneration is significantly lower in post-menopausal women, predisposing women to impaired muscle function. Since SCAMPs traffic critical cell surface modulators to and from the cell surface, we hypothesize that they may be critical for delivering essential cell surface components necessary for skeletal muscle regeneration. However, little is known about the underlying mechanisms of estrogen and SCAMPs in the process of skeletal muscle repair.

Materials and

Methods:  The gene sequences for mouse SCAMPs1-5 were taken from the National Institution of Health (NIH) database, and each of the genes was analyzed for the presence of 48 different EREs (Estrogen Response Element), using Python. We tested the impact of estrogen on SCAMP expression in the mouse muscle C2C12 cells line by treating them with and without estrogen (100pM) for 1, 4 and 24 hours in growth media, and 24 and 120 hours in serum reduced differentiation media. We extracted RNA, reverse-transcribed it to cDNA, and then used qRT-PCR to quantify the relative levels of expression of various genes, including levels of the SCAMP gene family and markers of muscle cell differentiation. Furthermore, cells were transfected with small inhibitory RNA (siRNA) against SCAMP1 to reduce its expression. siRNA against no known targets (scrambled controls) were used as controls. Cells were grown for 0 or 1 day in growth media or 1 or 4 days in low serum differentiation media and subjected to the same gene expression studies as above.

Results, Conclusions, and Discussions: 

Results: We found that the Estrogen Response Elements were present in all 5 SCAMPs. Each gene contained at least 1 ERE. 2 of the 48 EREs were located in the gene for SCAMP1, while the gene for SCAMP2 contained 3 different EREs. The gene for SCAMP3 only possessed 1 ERE. The gene for SCAMP4 was distinct as it had 3 EREs present in the gene sequence, with the same ERE found twice. The gene for SCAMP5 also contained 3 separate EREs within its gene sequence. There was no notable pattern to the location of the EREs in each of the SCAMPS, as they all varied in location within the gene sequences. Overall, these findings show us that each SCAMP has EREs, but the amount and the type of ERE varies amongst the 5 SCAMP family members. To see the impact on muscle differentiation, we measured muscle differentiation markers, including  myogenin (MyoG) and muscle creatine kinase (MCK). Significant differences in gene expression of the SCAMP family and muscle differentiation markers in cells treated with estrogen. Furthermore, the knockdown of  SCAMP1 was efficient, significant, and specific as the gene expression of remaining SCAMPs 2-5 was not reduced. We further observed a statistically significant decrease in MyoG and MCK expression after 1 day in differentiation media with knock-down of SCAMP1.

Conclusions/Discussions: Our results indicate that SCAMPs play critical roles in myogenesis, a key step in skeletal muscle regeneration. Furthermore, our results indicate a potential role for estrogen in regulating skeletal muscle regeneration through SCAMPs. Future studies will assess the protein expression and localization of SCAMPs, muscle cell differentiation markers, and cell cycle markers to determine the mechanisms of estrogen’s regulation of myogenesis. 

Understanding the mechanisms of estrogen in modulating muscle regeneration will have a significant impact on developing novel therapeutics for combatting the asymmetric sarcopenia experienced by post-menopausal women. Improvement of skeletal muscle health in post-menopausal women can improve quality of life, as well as bone and cognitive health. Additionally, this will increase the mechanistic understanding of skeletal muscle in women’s health, which is historically understudied.

Acknowledgements (Optional):