Rapid Intracellular Delivery of Human Heat Shock Protein 72 Inhibits Neurodegeneration and Oxidative Damage After a Traumatic Brain Injury

Abstract

Fv-HSP72 is a rapid cell-penetrating human heat shock protein for the treatment of traumatic organ injuries. We have shown this re-engineered protein (HSP72) is capable of crossing the blood brain barrier (BBB) of rats suffering a controlled cortical impact (CCI) and remains in brain tissue for up to 12 hours; long after clearance from the cortex of uninjured rats. Peptide sequences unique to Fv-HSP72 allow for its differential detection from endogenous HSP72. Male Sprague-Dawley rats were divided into 10 groups of n=10 with those animals receiving a CCI subjected to a unilateral cortical contusion simulating a moderate to severe brain injury using an electronically controlled pneumatic impact device. Control groups were either uninjured (Sham), injured (TBI Only), or injured and given buffer (TBI+Vehicle). Rats treated with one of three Fv-HSP72 variants were dosed at 10 or 30mg/kg 15m post-impact, then sacrificed 48 hours later. Cortical tissues were extracted from the ipsilateral and contralateral hemispheres for biomarker analysis. Here we report results of our drug inhibiting neurodegeneration based on five biomarkers (NF-L, pNF-H, pTau [T181, T231, S396]). These results were statistically significant, especially for one of the Fv-HSP72 variants, when comparing differences both between treatment groups and within groups (i.e. when comparing ipsi-vs. contralateral hemispheres). Significant inhibition of oxidative stress (3-NT) and inflammatory (IL-6) biomarkers were also observed (both p<0.0001). With similar results obtained for a blast injury model being published elsewhere, the analyses suggest Fv-HSP72 is neuroprotective following a direct impact brain injury. One sentence summaryThis study describes the effectiveness of a biologic agent, Fv-HSP72, in significantly inhibiting neuronal tissue damage in the brain when administered after a direct cortical impact.