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.

High School Student with a Traditionally Underrepresented Background

HS Poster

Poster 31 - Axon Degradation of Dorsal Root Ganglion Cells from Laser Ablation Damage in the presence of M-div Inhibitor

Saturday, October 26, 2024
10:00 AM - 12:00 PM EST
Location: Exhibit Hall E, F & G

    Presenting Author(s)

  • Sophia Liu (she/her/hers)

    IEM OPALS Intern
    UCSD Institute of Engineering in Medicine, California, United States

  • AX

    Anne Xie (she/her/hers)

    IEM OPALS Intern
    UCSD: Institute of Engineering in Medicine
    San Diego, California, United States

    • Co-Author(s)

  • Michelle Sun (she/her/hers)

    IEM OPALS Intern
    UCSD Institute of Engineering in Medicine
    San Diego, California, United States

  • MS

    Murong Su

    IEM Undergraduate Researcher
    Institute of Engineering in Medicine, United States

  • PR

    Paisley A. Ruddy (she/her/hers)

    Undergraduate
    UCSD
    EL CAJON, California, United States

  • JS

    Jiyeon Song

    Intern
    UCSD Institute of Engineering in Medicine, United States

  • CW

    Chengbiao Wu

    Professor
    UCSD School of Medicine Dept of Neuroscience, Outreach Program for Advancing Learning in STEM (OPALS), United States

  • VG

    Veronica Gomez-Godinez

    Scientist
    University of California, San Diego
    La Jolla, California, United States

    • Last Author(s)

  • Linda Shi, PhD (she/her/hers)

    OPALS Program Director, Project Scientist, Co-director IEM
    University of California, San Diego: Institute of Engineering in Medicine
    La Jolla, California, United States


Introduction: The dorsal root ganglion (DRG), as known as spinal ganglion, is the cluster of nerves located at the dorsal root in the spinal cord. These nerves function as a “bridge” by connecting the peripheral and central nervous systems, allowing sensory signals to be received and transmitted. As DRGs, Mitochondrial division inhibitor 1 (Mdivi-1) selectively inhibits dynamin-related protein 1 (Drp1), which is critical for mitochondrial fission, synonymous with neurodegenerative diseases and nerve injuries. This study aims to analyze the effects of Mdivi-1 on axon degradation in terms of axon thickness and axon separation, highlighting the potential usage of Mdivi-1 to mitigate axonal damage.

Materials and

Methods: DRG tissue from mouse E18 embryos was extracted and rinsed in HBSS with 1% P/S, then dissociated in 0.25% trypsin at 37°C. The DRG cells were then triturated, and cultured in plating media. Poly-L-lysine (Invitrogen) was used to pre-coat the culture dishes. To suppress the proliferation of non-neuronal cells, Arabinosylcytosine (AraC) was added to the maintenance medium at a final concentration of 1µM. Regular maintenance medium (without AraC) and selection maintenance medium (containing AraC) were used on alternating days until the conclusion of the experiments. We treated select cultures of DRG neurons with Mdivi-1, a Drp1 inhibitor, at a concentration of 100 uM for 60 minutes. Experiments were carried out on the 7th day in vitro (DIV).
The laser ablation system (Robolase III) utilizes a Near IR Ti-Saph femtosecond laser, which passes through a rotating polarizer, setting the power to 120mW when measured before the objective lens. The beam was shuttered to only allow transmission when cutting was necessary. Then, it was passed through beam steering optics and telescoped to expand the beam to a radius the size of the back of the objective. A mirror was used to direct the beam towards a Zeiss 40x NA 1.3 oil objective mounted on a Zeiss Axiovert 200M inverted microscope [1]. This allowed for submicron-level damage on axons. Cells were imaged under phase microscopy on a humidified heated stage (Ibidi) supplying 5% CO2 for 60 minutes.

Results, Conclusions, and Discussions: In this study, the axon thickness of non-treated DRGs decreased by 59.85% over 60 minutes. In comparison, the axon thickness of Mdivi-1 treated DRGs decreased 36.05% over 60 minutes, resulting in a 39.77% decrease in degradation. The axon separation of the non-treated cells measured 87.190 microns on average over 60 minutes, while Mdivi-1 treated cells averaged 11.506 microns in separation, resulting in an 86.80% decrease in separation.
The application of Mdivi-1 significantly decreases the axonal degradation in DRG neurons following laser ablation injury, suggesting that inhibition of Drp1-mediated mitochondrial fission has a protective effect on axonal integrity. The observed improvements show the potential of Mdivi-1 and other mitochondrial inhibitors as novel therapies and treatments for nerve degeneration and nerve-related disorders.

Acknowledgements (Optional): This work was supported by a generous gift from Beckman Laser Inc. to Dr. Linda Shi. The high school students (*) participated in the UCSD IEM OPALS internship. Special thanks to Dr. Shu Chien for supporting the OPALS program.

References (Optional): [1] Michael W. Berns, et al. Chapter 5 Laser Scissors and Tweezers, Methods Cell Biol., 1997, 55, 71-98.