Development of diversified HTS cell-based assays for solute carrier drug discovery.

Solute carrier (SLC) transporters comprise a family of >450 membrane-bound proteins that facilitate the transport of a wide array of substrates across biological membranes. They play a fundamental role in controlling the transport of molecules, such as ions and metabolites, across the cell membranes. Despite the availability of marketed drugs targeting well-known SLC transporters, such as neurotransmitter (i.e. SERT, NET, DAT) and glucose (GLUTs) transporters, most of the SLCs are still under-investigated as therapeutic targets. A major limiting factor in this area is the lack of suitable assays and tools that enable High Throughput Screening (HTS) of large compound collections, aiming to identify novel therapeutics. In the context of the Innovative Medicines Initiative consortium RESOLUTE, we developed cell-based assays for several SLCs employing a variety of scientific approaches and technologies suitable for running fully automated HTS. Here, we describe the functional assays developed for five SLCs: SLC59A1 (MFSD2A), SLC59A2 (MFSD2B), SLC6A8 (CRTR), SLC9B2​ (NHA2) and SLC12A2 (NKCC1). All these transporters play relevant roles in different pathological conditions, but they still lack drugs able to specifically activate or inhibit them. To address this gap, we have developed and optimized in a miniaturized format cellular assays that enable streamlined and high-throughput investigation of compound libraries. These assays offer a valuable platform for the identification of new therapeutic modulators targeting these underexplored SLCs in a fast and efficient manner.