Green said his group tested several selective CSF1R inhibitors that are under investigation as cancer treatments and immune system modulators. Of these compounds, they found the most effective to be a drug called PLX3397, created by Plexxikon Inc., a Berkeley, Calif.-based biotechnology company and member of the Daiichi Sankyo Group. PLX3397 is currently being evaluated in phase one and two clinical trials for multiple cancers, including glioblastoma, melanoma, breast cancer and leukemia.
Crucially, microglial elimination lasted only as long as treatment continued. Withdrawal of inhibitors produced a rapid repopulation of cells that then grew into new microglia, said Green, who’s a member of UC Irvine’s Institute for Memory Impairments and Neurological Disorders.
This means that eradication of these immune cells is fully reversible, allowing researchers to bring microglia back when desired. Green added that this work is the first to describe a new progenitor/potential stem cell in the central nervous system outside of neurogenesis, a discovery that points to novel opportunities for manipulating microglial populations during disease.
SOURCE: UCI News