There’s a nice editorial in Nature Neuroscience about the Broad Institute’s PsychHTS initiative. The initiative invites scientists from outside the Broad to suggest new high-throughput screens that the Broad will perform. The Broad has invested heavily in capital equipment and expertise for chemical biology screens (ie. small molecule drug libraries with robotic delivery and automated screening). These libraries are huge: 50,000-500,000 molecules can be screened. Although much science is hypothesis driven, this kind of large-scale hypothesis-free exploration just hasn’t been possible before. And this certainly isn’t the kind of thing that can be done in a single lab; only dedicated facilities like those at the Broad could carry out this type of “big science.” For collaborators hoping to use the Broad platform, the key appears to be in developing a good automated assay:
Readouts may be anything from classical enzymatic reactions, through FRET for changes in protein interaction, up to subcellular changes captured by automated high-content imaging. An investigator may send a group member to the Broad to take advantage of its resources or may entirely ‘outsource’ assay development to the chaperone. Assay development typically takes two to three months, sometimes up to a year. The assay is then used to screen one or more compound libraries, encompassing at present up to 400,000 substances and growing. (PsychHTS pays for screening a 50,000-compound subset.) ‘Hits’—compounds that affect the assay results in a way that indicates potential usefulness in a psychiatric research context—are automatically retested at several concentrations. The resulting collection of typically between 50 and 500 confirmed hits is then evaluated and prioritized according to criteria of scientific interest and potential drug promise, and thereby winnowed down to the top 10 or 20. The Broad Institute’s organic chemists then synthesize and retest these compounds plus a series of their chemical derivatives, with goals such as improved solubility and more specific binding to putative targets. The goal of the entire procedure is to deliver small-molecule probes that modulate a specific cellular function—essentially tools for subsequent research into the initial hypothesis regarding a psychiatric disease mechanism.
At this point, the new small-molecule probes will need to be tested in animal models of mental illness.
The most appealing aspect is that the Broad is opening up the process to anyone with good ideas for potential screens. The next application deadline is in September. Considering both PsychHTS and the Allen Brain Atlas, is neuroscience moving away from an individual lab model and more toward a “big science” model of projects with lots of collaboration?