Fig 3. Chemical structures of the hit compounds selected through in silico HTS on GPR17.

Compounds from 1 to 6 are the progenitors of the three chemical families (see also S1 Fig) identified through the earliest virtual screening. Together with compounds 4 and 6, compounds from 7 to 19 were selected among the ~1,000,000-compound library for preliminary in vitro testing. Compounds from 7 to 17 belong to Family I; compound 18 and 19 are representative of Family II and III, respectively.