Inhibition of phosphodiesterase 10A mitigates neuronal injury by modulating apoptotic pathways in cold-induced traumatic brain injury

Brain injury develops from a complex series of pathophysiological phases, resulting in acute necrotic or delayed apoptotic cell death after traumatic brain injury (TBI). Inhibition of apoptotic cell death is critical for the treatment of acute neurodegenerative disorders, such as TBI. Here, we investigated the role of phosphodiesterase 10A (PDE10A) in the development of neuronal injury, particularly in apoptotic cell death. Using the PDE10A inhibitor TAK-063, we found that PDE10A inhibition is associated with decreased brain injury, brain swelling, and blood brain barrier disruption 48 h after cold-induced TBI. Furthermore, a particularly notable result was observed with 3 mg/kg TAK-063, which reduced disseminated neuronal injury. Protein abundance analysis revealed that PDE10A inhibition activates survival kinases AKT and ERK-1/-2, which were associated with the decreased activation of MMP-9 and PTEN. Additionally, iNOS and nNOS levels significantly reduced in the TAK-063 group, playing roles in inflammation and apoptosis. A planar surface immunoassay was performed for in-depth analyses of the apoptotic signaling pathways. We observed that inhibition of PDE10A resulted in the decreased expression of TNFRSF1A, TNFRSF10B, and TNFRSF6 receptors, particularly inducing apoptotic cell death. Moreover, these findings correlated with reduced levels of pro-apoptotic proteins, including PTEN, p27, Cytochrome-c, cleaved Caspase-3, Bad, and p53. Interestingly, TAK-063 treatment reduced levels of anti-apoptotic proteins or enzymes, including XIAP, Claspin, and HIF1α, without affecting Bcl-x, MCL-1, SMAC, HO-1, HO-2, HSP27, HSP60, and HSP70. The findings suggest that PDE10A regulates cellular signaling predominantly pro-apoptotic pathways, and inhibition of this protein is a promising approach for the treatment of acute brain injury.