Neurotrauma induced retinal basement membrane COL4A1 defects are restored by adipose tissue derived mesenchymal stem...

COL4A1 defects are known to cause a variety of multisystem disorders with significant vascular dysfunction leading to neuronal damage. Case reports suggest that patients with COL4A1 mutations or extracellular COL4A1 deficiency in the basement membrane may put individuals at increased risk for developing visual deficits with neurotrauma. However, no experimental evidence is available. This study investigated the impact of Col4a1 deficiency on visual dysfunction following mild traumatic brain injury (mTBI) and evaluated the therapeutic efficacy of COL4A1-enriched adipose-derived stem cell-conditioned medium (ASC-CCM) in mitigating associated neurovascular deficits.

Using a retina-targeted knockdown approach in C57Bl/6 mice via intravitreal delivery of AAV2-Col4a1 shRNA, followed by a controlled 50-psi air-blast to induce mTBI, we assessed visual performance, retinal histopathology, and gene expression profiles for 4 weeks post-injury. Treatment with ASC-CCM was administered intravitreally post-blast. In-vitro, Col4a1 knockdown in human retinal endothelial cells (HRECs) assessed the therapeutic benefit of COL4A1-enriched ASC-CCM.

After blast injury, Col4a1-deficient mice displayed significantly greater reductions in visual acuity and contrast sensitivity thresholds compared to control mice, which were substantially restored following ASC-CCM treatment. Histological and molecular analyses revealed marked glial activation, vascular instability, and synaptic disorganization in Col4a1-deficient retinas post-injury, which were attenuated upon ASC-CCM administration. In-vitro assays further confirmed that COL4A1 plays a crucial role in endothelial integrity. After Col4a1 knockdown, HRECs showed impaired cell migration and increased leukocyte transmigration, effects that were reversed by treatment with COL4A1-enriched, but not COL4A1-depleted, ASC-CCM. Moreover, COL4A1-enriched ASC-CCM suppressed inflammatory responses in cytokine-stimulated microglia and stabilized TNF-α-induced endothelial permeability.

These findings collectively identify COL4A1 deficiency as a sensitizing factor for post-traumatic visual dysfunction and demonstrate that ASC-CCM exerts therapeutic effects by preserving retinal vascular structure and modulating inflammatory responses, positioning it as a promising candidate for treating TBI-related ocular neurovascular injury.