Discovery of novel compound promotes neurogenesis by activation of mTOR signaling

Neurodegenerative disorders are continually increasing in incidence due to higher life expectancy. Currently, limited therapeutic strategies are available for affected patients, most targeting symptomatic treatment. mTOR pathway is identified as important player in neurogenesis that modulates healthy neuron growth and differentiation. Moreover, many neurodegenerative disorders are associated with downregulated mTOR signaling. However, mTOR activation can also lead to uncontrolled cell proliferation, promoting cancer. This careful balance limits the development of mTOR as a target for modulation of neuronal growth. Recently, selected classes of antidepressants were reported to activate mTOR pathways, causing dendritic outgrowth and increased synaptic protein levels. Although results were promising, they require treatment with up to 100 μM of tested compounds. To identify potential utilization of penfluridol, an anti‐psychotic agent, as a neuron growth modulator, we have screened this compound and its analogs using reported methodology. Although no activity was observed for PFL, one of its analogs, PF331, promoted neurogenesis in primary neurons. In particular, treatment with PF331 (100 nM,1 μM) for 5 days during reoxygenation (post‐stroke conditions) resulted in improved neurite outgrowth. At the same time, no effect on the viability of the primary neurons was observed under normoxic conditions and during the reperfusion stage. Further, we have established that observed activity was not related to the overstimulation of mTOR pathway, but rather to the compound’s ability to restore mTOR activation to the pre‐stress levels. We hypothesized that PF331 will have minimal impact on cancer proliferation and confirmed it in vivo , where our compound had no effect on cancer growth. Stroke is one of the pathological conditions characterized by hypoxia‐induced damage to neurons. Hence, we have proposed to evaluate our compound for the ability to lessen hypoxia‐induced damage using in‐vivo stroke model with prior confirmation of the ability of PF331 to cross the BBB in vivo and to achieve desired levels in the brain. In conclusion, PF331 has shown the ability to promote neurite outgrowth in primary neurons and restore mTOR activation in the hypoxic in vitro model. Because of its biological activity and favorable in vivo PK profile, we envision that this compound is a potential candidate for the treatment of neurodegenerative diseases, such as stroke.Evaluation of the effect of PF331 on primary neurons Evaluation of the effect of PF331 on of primary neurons. Neurons were subjected to 3 hrs of OGD followed by 4 (A and B)/ 5 (C) days of oxygenation to mimic ischemia reperfusion injury. (A–B) OGD reperfusion (OGDR) down‐regulates mTOR and ERK compared to normoxic (Nor) condition whereas treatment with Compound PF331 activates mTOR and ERK. (C) PF331 facilitates dendritic outgrowth and increased number of synapses.