Developing GPR37 activators as non-opioid pain therapeutics

National Center For Advancing Translational Sciences

Investigators

Abstract

During this fiscal year, the SCTL generated iPSC-derived nociceptors and demonstrated that these cells express key receptors required for this study; GRP37, GRP37L, TRPV1 and GDNF. Characterization of day 28 iPSC-derived nociceptors via RNA-Seq, immunostaining and protein expression analysis were used to comfirm that our nociceptors express these receptors. Bulk RNA sequencing demonstrated that our hPSC-derived sensory neurons (hPSC-SNs) expressed GPR37 and that GPR37 is co-expressed in TRPV1+-hPSC-SNs based on immunocytochemistry. An important objective of this collaboration is to determine the response of our hPSC-SNs to TX14, a GPR37 agonist, in normal and sensitized states, which in turn is expected to release GDNF from TRPV1+ sensory neurons. As our hPSC-SN maturation medium is supplemented with GDNF, we tested whether omission of GDNF in our hPSC-SN cultures for 7 days (7 d) between D28-35 would affect cell viability and gene expression. We observed no difference in cell viability or neuronal morphology in D35 hPSC-SNs with or without 7 d of GDNF. Bulk RNA sequencing was performed on samples from D35 hPSC-SNs with or without 7 d GDNF and bioinformatic analysis is ongoing. Furthermore, preliminary multi-electrode array recordings were performed to model sensitized states in SN. We demonstrated that our hPSC-SNs can be sensitized following exposure to inflammatory soup (a four-part cocktail comprised of prostaglandin E2, bradykinin, histamine, and serotonin) and several cytokines including TNFα, IL-6, and IL-1β. Ongoing analysis will determine the effects of TX14 on our hPSC-SNs under normal and sensitized states, and changes gene/protein expression profiles in normal and pain conditions.