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(OR22-02-26) The Impact of Dietary Serine and Glycine Availability on Aged Skeletal Muscle Immune Cell Composition Following Injury

Monday, July 27, 2026
4:42 PM - 4:54 PM ET
Location: National Harbor 4-5

    Presenting Author(s)

  • Ryan Dannemiller, BS (she/her/hers)

    Graduate Student
    The University of Alabama at Birmingham
    Birmingham, Alabama, United States

    Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

    • Co-Author(s)

  • SR

    Shelby Rorrer

    The University of Alabama at Birmingham, United States

  • WM

    Wenxia Ma

    The University of Alabama at Birmingham, United States

  • AY

    Angad Yadav, PhD (he/him/his)

    Research Scientist Senior
    The University of Alabama at Birmingham
    Birmingham, Alabama, United States

  • MA

    Matthew Alexander

    The University of Alabama at Birmingham, United States

  • Anna Thalacker-Mercer, PhD

    Associate Professor
    The University of Alabama at Birmingham
    Birmingham, Alabama, United States

Disclosure(s):
Ryan Dannemiller, BS: No relevant financial relationship(s) with ineligible companies to disclose.
Anna Thalacker-Mercer, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Serine and glycine (ser/gly) are nutritionally non-essential amino acids that are required for protein synthesis, metabolism, and cellular processes and structure. Our lab previously determined that endogenous availability of ser/gly declines with aging in both the circulation and skeletal muscle (SkM). Further, we found that when aged mice were fed a diet absent of ser/gly, which further reduces endogenous ser/gly availability, that SkM regeneration was impaired and intermyofiber adipocytes accumulated following injury. Other studies identified that dietary ser/gly depletion impacts immune cell composition and inflammatory response following infection. The objective of this study is to determine if a disruption in immune/inflammatory response to injury occurs in aged mice with dietary ser/gly depletion is unknown but offers a potential understanding of the negative impact of disrupted regenerative response to injury in aged mice.

Methods: Aged female C57BL/6N mice were randomized to either a ser/gly control (SGCNT) or ser/gly depleted (SGDEP) diet. Each diet was an amino acid defined diet. The SGCNT diet contained 9.4 g/kg ser and 3.1 g/kg gly and the SGDEP diet contained no ser/gly. Both diets were isonitrogenous and isoenergetic. Mice were acclimated to the diet for four weeks prior to injury (i.e., intramuscular myotoxin injection in both tibialis anterior muscles). Muscles were collected 0, 3, 5, and 14 days post injury (dpi) and analyzed using qPCR to identify changes in cytokine abundance (pro-inflammatory: Il6, Tnf; anti-inflammatory: Il4, Il10, and Gata3), and with immunohistochemistry for macrophage abundance (pro-inflammatory: M1; anti-inflammatory: M2).

Results: We identified greater levels of cytokines and immune specific genes (Il6, Tnfα, Il4, Il10, and Gata3) in the SGDEP (vs. SGCNT) at 3 dpi. Intriguingly, there was ~200 fold increase of anti-inflammatory cytokines, when a pro-inflammatory response is expected, indicating altered immune response. Supporting this, we identified crown-like macrophage structures and a significant increase in M2 macrophages in the SGDEP (vs. SGCNT) at 3 dpi.

Conclusions: These results support the hypothesis that reduction of dietary ser/gly results in a robust anti-inflammatory phenotype and impaired SkM regeneration post-injury.

Funding Sources: This research was supported by NIA funded grants.