Role Of Receptor Protein Tyrosine Phosphatase Beta/Zeta In Neuron-Microglia Communication In A Cellular Model Of Parkinson'S Disease

Pleiotrophin (PTN) is a neurotrophic factor that regulates glial responses in animal models of different types of central nervous system (CNS) injuries. PTN is upregulated in the brain in different pathologies characterized by exacerbated neuroinflammation, including Parkinson's disease. PTN is an endogenous inhibitor of Receptor Protein Tyrosine Phosphatase (RPTP) beta/zeta, which is abundantly expressed in the CNS. Using a specific inhibitor of RPTP beta/zeta (MY10), we aimed to assess whether the PTN/RPTP beta/zeta axis is involved in neuronal and glial injury induced by the toxin MPP+. Treatment with the RPTP beta/zeta inhibitor MY10 alone decreased the viability of both SH-SY5Y neuroblastoma cells and BV2 microglial cultures, suggesting that normal RPTP beta/zeta function is involved in neuronal and microglial viability. We observed that PTN partially decreased the cytotoxicity induced by MPP+ in SH-SY5Y cells underpinning the neuroprotective function of PTN. However, MY10 did not seem to modulate the SH-SY5Y cell loss induced by MPP+. Interestingly, we observed that media from SH-SY5Y cells treated with MPP+ and MY10 decreases microglial viability but may elicit a neuroprotective response of microglia by upregulating Ptn expression. The data suggest a neurotrophic role of microglia in response to neuronal injury through upregulation of Ptn levels.