Treatment of Traumatic Brain Injury Using Zinc-Finger Protein Gene Therapy Targeting VEGF-A

Abstract

Vascular endothelial growth factor (VEGF) plays a role in angiogenesis and has been shown to be neuroprotective following central nervous system trauma. In the present study we evaluated the pro-angiogenic and neuroprotective effects of an engineered zinc-finger protein transcription factor transactivator targeting the vascular endothelial growth factor A (VEGF-ZFP). We used two virus delivery systems, adeno-virus and adeno-associated virus, to examine the effects of early and delayed VEGF-A upregulation after brain trauma, respectively. Male Sprague-Dawley rats were subject to a unilateral fluid percussion injury (FPI) of moderate severity (2.2-2.5 atm) followed by intracerebral microinjection of either adenovirus vector (Adv) or an adeno-associated vector (AAV) carrying the VEGF-ZFP construct. Adv-VEGF-ZFP-treated animals had significantly fewer TUNEL positive cells in the injured penumbra of the cortex (p<0.001) and hippocampus (p=0.001) relative to untreated rats at 72 h post-injury. Adv-VEGF-ZFP treatment significantly improved fEPSP values (p=0.007) in the CA1 region relative to injury alone. Treatment with AAV2-VEGF-ZFP resulted in improved post-injury microvascular diameter and improved functional recovery on the balance beam and rotarod task at 30 days post-injury. Collectively, the results provide supportive evidence for the concept of acute and delayed treatment following TBI using VEGF-ZFP to induce angiogenesis, reduce cell death, and enhance functional recovery.

Combination of growth factor treatment and scaffold deposition following traumatic brain injury has only a temporary effect on regeneration

“…infusion for one week will greatly expand the stem cell pool around the ventricles (Craig et al, 1996). Based on the results of others we hypothesized that VEGF would induce migration of the expanded stem cell population to the injury site (Jin et al, 2002;Siddiq et al, 2012;Zhang et al, 2003), where differentiation and survival of the stem cells into neurons and glia would be supported by the ECM-scaffold. The ECM-scaffold has previously been extensively used to promote stem cell adhesion and differentiation in vitro (Uemura et al, 2010).…”

“…Moreover, VEGF is known to be the key factor in the regulation of endothelial cells and vessel formation (Karamysheva, 2008). Inducing over-expression of VEGF-A using adenoviral delivery of a specific promotor was recently shown to decrease motor deficits and reduce cell death after TBI in rats (Siddiq et al, 2012). These previous investigations clearly indicate that both EGF and VEGF are interesting as potential neuroprotectors and stem cell activators after acute brain injury.…”

“…The improvement found by Sun et al in MWM performance could at least partly be explained by more surviving neurons in the CA3 and hilus of the dentate gyrus in the hippocampus, in GF-treated animals(Sun et al, 2010), however, the authors did not see any increase in neurogenesis 28 days after injury and no MWM experiments were performed at later time points. In a recent study it was demonstrated that upregulation of VEGF following TBI in rats reduced the number of TUNEL positive cells in hippocampus at 72 h and 7 days, but had no positive effect on MWM performance from 10-30 days post-trauma(Siddiq et al, 2012).…”

Growth factor therapy sequesters inflammation in affording neuroprotection in cerebrovascular diseases

“…VEGF also plays a key role in providing protection following CNS trauma – specifically TBI [48]. To date, there is evidence that upregulation of VEGF-A has protective benefits in both early and late treatment of TBI [48].…”

“…To date, there is evidence that upregulation of VEGF-A has protective benefits in both early and late treatment of TBI [48]. A virus delivery system was coupled with an engineered zinc-finger protein transcription factor transactivator in order to monitor the upregulation of VEGF [48].…”