Identifying Druglike Inhibitors of Myelin-Reactive T Cells by Phenotypic High-Throughput Screening of a Small-Molecule Library

Abstract

Inflammatory T cells that are reactive to myelin protein components of the CNS play a critical role in the pathogenesis of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). The authors have previously generated mice that predominantly harbor T cells transgenic for a T-cell receptor (TCR) that is specific to the myelin proteolipid protein (PLP) 139-151 and that spontaneously develop MS-like paralysis. T cells from healthy transgenic mice respond to stimulation with PLP139-151 in a highly specific manner by proliferation and secretion of proinflammatory cytokines such as interleukin (IL)-2 and interferon (INF)-gamma in vitro. To identify druglike compounds that may inhibit inflammatory T-cell responses, the authors have developed a high-throughput screening assay with primary T cells from PLP TCR transgenic mice. They have screened 41,184 small-molecule compounds that follow Lipinski's rules for their inhibitory activity on the proliferation and secretion of proinflammatory cytokines in PLP-reactive T cells. To this end, the screen identified 6 nontoxic compounds with a molecular weight <500 that inhibited inflammatory responses in PLP-reactive T cells in a concentration-dependent fashion. The identified compounds represent valid leads that may be developed into novel therapeutics for MS that could be administered orally.

Lessons Learnt from Assembling Screening Libraries for Drug Discovery for Neglected Diseases

“…On the other hand, smaller libraries containing between 14 000 and 135 000 compounds have been successfully screened for hit discovery 16–19. In a less competitive area with restricted resources, such as translational research for orphan or neglected diseases, these smaller libraries are very appealing.…”

“…On the other hand, smaller libraries containing between 14000 and 135000 compounds have been successfully screened for hit discovery. 16 – 19 In a less competitive area with restricted resources, such as translational research for orphan or neglected diseases, these smaller libraries are very appealing. Such collections might not reveal every single hit series that would have been discovered using larger libraries and only limited initial SAR, but by careful selection of libraries to cover lead-like chemical space in as diverse as possible manner, they should generate sufficient information to initiate a drug discovery programme.…”

High Throughput Screening in the Twenty-First Century

“…Examples include screens for compounds that arrest cells in mitosis, that block cell migration, and that block the secretory pathway [50], or assays with primary T cells from PLP TCR transgenic mice for their inhibitory activity on the proliferation and secretion of proinflammatory cytokines in PLPreactive T cells [51], and identification of small-molecule inhibitors of histone acetyltransferase activity [52].…”