D15-a - Lignin Macrophage

Saturday, October 11, 2025

10:00 AM - 12:00 PM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

ZC

Zara Chandrasekhar

Research Intern
Laboratory for Regenerative Tissue Repair, Department of Pediatric Surgery, Baylor college of Medicine and Texas Children’s Hospital., United States

Primary Investigator(s)

AK

Arin Kumar

Research Intern
Laboratory for Regenerative Tissue Repair, Department of Pediatric Surgery, Baylor college of Medicine and Texas Children’s Hospital., United States

Co-Author(s)

ML

Mary Hui Li

Research Scientist
Laboratory for Regenerative Tissue Repair, Department of Pediatric Surgery, Baylor college of Medicine and Texas Children’s Hospital., United States

Introduction: : This study explores lignin-based antioxidant composites as a new therapy for diabetic wound healing. In cell studies, lignin nanoparticles shifted macrophages from a pro-inflammatory (M1) state to an anti-inflammatory (M2) state in a dose-dependent way. In diabetic mice, treatment lowered inflammatory cell infiltration and increased M2 macrophages, although wound closure did not change significantly. These results suggest that lignin composites may support healing by reducing inflammation and promoting beneficial immune responses.

Materials and

Methods: : Macrophages from C57BL/6J mice were cultured and either left unstimulated or stimulated with LPS and IFNγ to induce an inflammatory (M1) state. Cells were then treated with Cy5-labeled thiolated lignosulfonate (TLS) nanoparticles at 1 or 3 mg/mL for 24 hours. Uptake was visualized by fluorescence imaging, while qRT-PCR and ELISA measured inflammatory (NOS2, IL-1B, IL-6, CD86) and anti-inflammatory (ARG1, CD206) markers. Cell density was also assessed. For in vivo studies, full-thickness 6 mm excisional wounds were created in diabetic (db/db) mice and treated with either no therapy, gelatin methacrylate (GelMA), or GelMA+TLS nanoparticles. Wound tissues were collected at day 7 and analyzed by H&E for closure, and by immunostaining (CD45, F4/80, CD206, ARG1) for inflammatory and macrophage phenotypes. Data were evaluated using ANOVA with Tukey’s post hoc test.

Results, Conclusions, and Discussions:: Cy5-TLS nanoparticles were efficiently taken up by macrophages as shown by fluorescence imaging. In unstimulated cells, treatment reduced pro-inflammatory markers, including a ~5-fold decrease in IL-6 and ~2-fold decrease in IL-1B, while increasing the M2 marker CD206 by ~2.25-fold. As expected, LPS/IFNγ stimulation greatly increased M1 markers (NOS2, IL-1B, IL-6, CD86) and decreased CD206. TLS treatment of stimulated cells reversed this trend, reducing NOS2, CD86, and ARG1 while increasing CD206 in a dose-dependent manner, with 3 mg/mL being most effective. Cell density was also reduced after 24 hours of treatment in both unstimulated and stimulated conditions. In vivo, GelMA+TLS treatment of diabetic mouse wounds did not significantly alter wound closure or granulation tissue area at day 7, but did reduce CD45+ leukocyte infiltration and increase CD206+ macrophages compared to controls.

Acknowledgements and/or References (Optional): : Zara Chandrasekhar1, Arin Kumar1, Taylor Lee1, Benjamin S. Barton2, Vincent Wollner1, Varun Akondy1, Casey Baxter1, Ling Yu1, Hui Li1, Mary Elizabeth Guerra1, Jangwook P. Jung2, Swathi Balaji1
1Department of Pediatric Surgery, Texas Children’s Hospital & Baylor College of Medicine, Houston, TX
2Department of Biological Engineering, Louisiana State University, Baton Rouge, LA