L. Yao, K. Bustamante-Fuchs, K. Cantu, T. Shippy
Wichita State University,
United States
Keywords: nanofiber, protein, neural repair, electrospinning
Summary:
Nanofiber scaffolds showed promising applications in tissue regeneration as a tissue engineering approach. As the structure of nanofiber scaffolds closely resembles the extracellular matrix (ECM) morphology, they can function as implantable materials for the repair of wounded neural tissues and enable regeneration. Collagen is a type of extracellular matrix molecule that provides structural support for cell attachment and soy protein can potentially modulate neural immune activity. Nanofiber scaffolds fabricated from these proteins may enhance the neural repair process as the scaffolds can guide the regrowth of the neural tissue. Potentially, the nanofibers can also function as implantable scaffolds for cell delivery and transplantation. Studies reported that transplantation of fetal astrocytes may stimulate axonal regeneration and functional recover after spinal cord injury. After neural injury, different from adult astrocytes, fetal astrocytes can potentially create a more conducive environment for regeneration. Additionally, fetal astrocytes may produce factors for neuron protection and therefore promote neuron survival. In this study, we fabricated protein and polymer composite nanofibers by electrospinning and tested the fetal astrocyte response to the fibers. Soy protein isolate (SPI), collagen and polycaprolactone (PCL) were used to generate nanofibers by electrospinning. The fabricated nanofibers were characterized by fourier transform infrared (FTIR) test to confirm the fiber component. We found astrocytes showed high viability on the fibers. Flowcytometry test showed that the fiber component did not affect cell cycle. Time-lapse imaging was performed to study the dynamic migration of astrocytes on those fibers. We observed the cell dynamic migration on the fibers and quantified the cell migration velocity and distance. RNA-sequencing analysis revealed effects of the nanofibers on cell motility and immune response. The neurodegeneration pathway is enriched in down-regulated genes including IL1B, and IL6 for the cells on fibers containing SPI compared with fibers with only collagen and PCL. This suggests that SPI function can potentially regulate the immune response of neural cells in neural repair process. The focal adhesion pathway is enriched in up-regulated genes including RAC1, RAC2, and ROCK2 for the cells grown on SPI/PCL fibers. These genes positively regulate cell adhesion and motility. The findings in this study show that the protein and PCL composite nanofibers can be used for neural regeneration application. These bioscaffolds can potentially promote neural regrowth by providing conductive structure and functional regulation of the immune response.