INVESTIGATION OF THE REGENERATIVE POTENTIAL OF PROTEOGLYCAN 4A IN THE BRAIN IN ZEBRAFISH MODELS OF TRAUMATIC BRAIN INJURY AND DEMYELINATION

Traumatic brain injury (TBI) is a global health concern and a leading cause of death and disability. Currently, treatment options are limited to stabilizing the patient and preventing disease progression. Detailed transcriptomic analysis showed a dramatic increase in prg4a expression compared to uninjured controls during regeneration following TBI. Therefore, our aim is to unravel the dynamic expression profile and functional role of prg4a in regeneration following TBI and non-traumatic brain injury (NTBI). To determine the functional role of prg4a in brain regeneration, we utilized CRISPR-Cas9 technology to generate loss-of-function mutants and the Tol2 transposase system to establish gain-of-function overexpression lines. Adult zebrafish were subjected to TBI via telencephalic stab injury or NTBI via cerebroventricular microinjection. Regenerative capacity was assessed by immunofluorescence quantification of cell proliferation (PCNA), neurogenesis (HuC/D), and glial reactivity (GFAP). Furthermore, we performed qPCR and Western blot analyses to quantify the expression of specific signaling, immune response, and ECM remodeling markers. Analyses were conducted at 3 days post-injury (dpi), representing the peak proliferative phase, and 7 dpi, corresponding to the differentiation and resolution phase. We present immunofluorescence images and quantification characterizing the regenerative competency of prg4a mutants and overexpression lines compared to wild-type controls. Furthermore, qPCR and Western blot data reveal the differential regulation of key signaling pathway components, ECM remodeling, and immune response markers following injury. These findings provide new insights into the molecular machinery of brain regeneration and highlight prg4a as a potential target for therapeutic intervention in brain injury.