NICEFORO, A. | bioRxiv Science

bioRxiv2025

Analysis of astrocyte progenitors derived from human induced pluripotent stem cells in vitro and following transplantation into the intact spinal cord.

Functional improvement following traumatic spinal cord injury (SCI) remains limited, therefore, it is necessary to develop therapeutic interventions such as cell transplantation to replace lost cells and promote connectivity. While transplantation typically focuses on neurons, it is important to include other neural cells, such as immature astrocytes, to provide a permissive environment, promote neuroprotection and regeneration, and ultimately restore connectivity. In this study, we leveraged cellular engineering using human induced pluripotent stem cells (hiPSCs) to generate astrocyte progenitor cells (hAPCs). We tested two hiPSC lines (WTC11 and KOLF2.1J) to characterize the fate of the hAPCs in vitro and following transplantation at the cervical level of the intact spinal cord for up to 3 weeks. Our results demonstrated efficient and consistent differentiation of the hiPSCs into hAPCs, their survival and integration with the adult spinal cord, with no signs of tumors, deleterious outcomes, and unexpected locations. The ability to survive and the absence of adverse effects indicate that hAPC transplantation could be a safe element of therapy in treating spinal cord injuries.

neuroscience↗

bioRxiv2024

Challenges and Efficacy of Astrocyte-to-Neuron Reprogramming in Spinal Cord Injury: In Vitro Insights and In Vivo Outcomes

Traumatic spinal cord injury (SCI) leads to the disruption of neural pathways, causing loss of neural cells, with subsequent reactive gliosis and tissue scarring that limit endogenous repair. One potential therapeutic strategy to address this is to target reactive scar-forming astrocytes with direct cellular reprogramming to convert them into neurons, by overexpression of neurogenic transcription factors. Here we used lentiviral constructs to overexpress Ascl1 or a combination of microRNAs (miRs) miR124, miR9/9*and NeuroD1 transfected into cultured and in vivo astrocytes. In vitro experiments revealed cortically-derived astrocytes display a higher efficiency (70%) of reprogramming to neurons than spinal cord-derived astrocytes. In a rat cervical SCI model, the same strategy induced only limited reprogramming of astrocytes. Delivery of reprogramming factors did not significantly affect patterns of breathing under baseline and hypoxic conditions, but significant differences in average diaphragm amplitude were seen in the reprogrammed groups during eupneic breathing, hypoxic, and hypercapnic challenges. These results show that while cellular reprogramming can be readily achieved in carefully controlled in vitro conditions, achieving a similar degree of successful reprogramming in vivo is challenging and may require additional steps.

neuroscience↗