An In Vitro and Ex Vivo Analysis of the Potential of GelMA Hydrogels as a Therapeutic Platform for Preclinical Spinal Cord Injury

Abstract

Spinal cord injury (SCI) is a devastating condition with no curative therapy currently available. Immunomodulation can be applied as a therapeutic strategy to drive alternative immune cell activation and promote a proregenerative injury microenvironment. Locally injected hydrogels carrying immunotherapeutic cargo directly to injured tissue offer an encouraging treatment approach from an immunopharmacological perspective. Gelatin methacrylate (GelMA) hydrogels are promising in this regard, however, detailed analysis on the immunogenicity of GelMA in the specific context of the SCI microenvironment is lacking. Here, the immunogenicity of GelMA hydrogels formulated with a translationally relevant photoinitiator is analyzed in vitro and ex vivo. 3% (w/v) GelMA, synthesized from gelatin type‐A, is first identified as the optimal hydrogel formulation based on mechanical properties and cytocompatibility. Additionally, 3% GelMA‐A does not alter the expression profile of key polarization markers in BV2 microglia or RAW264.7 macrophages after 48 h. Finally, it is shown for the first time that 3% GelMA‐A can support the ex vivo culture of primary murine organotypic spinal cord slices for 14 days with no direct effect on glial fibrillary acidic protein (GFAP+) astrocyte or ionized calcium‐binding adaptor molecule 1 (Iba‐1+) microglia reactivity. This provides evidence that GelMA hydrogels can act as an immunotherapeutic hydrogel‐based platform for preclinical SCI.

ThermoCyte: an inexpensive open-source temperature control system for in vitro live-cell imaging

“…Transgenic D. rerio expressing GFP in neutrophils were imaged, with neutrophils exhibiting surveillant behaviour within the tail fin (figure 4c,d). Next, we cultured BV2 microglia, a widely used mouse cerebellar microglial cell line [24][25][26][27], and performed imaging at physiological temperature, 37°C, for 30 min (figure 4e). Microglia at this temperature exhibit typical ramified morphology and localized surveillant motions.…”

Exosomes derived from CD271+CD56+ bone marrow mesenchymal stem cell subpopoulation identified by single-cell RNA sequencing promote axon regeneration after spinal cord injury

“…After UV irradiation in the presence of LAP, it can be polymerized through free radical reaction, and effectively preserve drug factors and extend the half-life of drug release. In view of the advantages of GelMA such as plasticity, biocompatibility and biodegradability 46 , we prepared the Exos hydrogel sustained-release system and conducted a series of characterization. We found that it has good biocompatibility and simulates the mechanical properties of natural spinal cord.…”

Local delivery of EGFR+NSCs-derived exosomes promotes neural regeneration post spinal cord injury via miR-34a-5p/HDAC6 pathway

“…Samples were then frozen at −80 °C, lyophilized, and the dry weight (Wdry) was recorded. The swelling ratio was calculated as Wwet/Wdry [ 10 ].…”