Optimization and Characterization of SHIP1 Ligands for Cellular Target Engagement and Activity in Alzheimer's Disease Models

Jesudason, C. D.; Rangel-Barajas, C.; Beach, C. J.; Beck, D. E.; Caballero-Floran, I. H.; Clayton, W. B.; Da Silva, L.; David, J. C.; Doolen, S.; Faulkner, A. N.; Hamdani, A. K.; Huhe, H.; Huynh, K.; Imhoff, R. D.; Javens-Wolfe, J.; Mason, E. R.; Moussaif, M.; Singhal, K.; Soni, D. M.; Van Buuren-Milne, M.; Williams, S.-P.; Angus, S. P.; Chu, S.; Dage, J. L.; Hipskind, P. A.; Johnson, T. S.; Kadurah-Dauok, R. F.; Lamb, B. T.; Meikle, P. J.; Mesecar, A. D.; Palkowitz, A. D.; Quinney, S. K.; Sukoff Rizzo, S. J.; Oblak, A. L.; Richardson, T. I.

doi:10.64898/2025.12.31.697127

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bioRxiv · 10.64898/2025.12.31.697127

Optimization and Characterization of SHIP1 Ligands for Cellular Target Engagement and Activity in Alzheimer's Disease Models

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Abstract

Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP1), encoded by the gene INPP5D, is a lipid phosphatase that negatively regulates immune receptor signaling in hematopoietic cells and microglia. Here, we describe a pyridyl-pyrazole-piperidine scaffold and the lead compound 3-((2-chlorobenzyl)oxy)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl)pyridine (32), which demonstrates SHIP1 target engagement, brain exposure, and evidence of a central pharmacodynamic response in vivo. Structure-activity relationship studies, guided by biochemical and cellular assays using multiple human and murine protein constructs and cells, identified SHIP1-active ligands. A thermal shift assay using full-length SHIP1 was used to assess compounds for cellular target engagement, while studies in IL-4 conditioned THP-1 cells was used to demonstrate changes in downstream AKT signaling. Targeted lipidomics revealed changes in the overall phosphoinositide pool consistent with SHIP1 target engagement and reduction of phospho-AKT levels. In a protein-lipid overlay assay, compound 32 induced changes in the relative association of SHIP1 with multiple phosphatidylinositols on a membrane surface. In high-content cellular imaging assays, compound 32 enhanced the uptake of myelin/membrane debris and fibrillar amyloid by primary murine microglia, phenocopying a genetic model with reduced SHIP1 expression. Finally, oral administration of compound 32 resulted in brain exposure sufficient to alter gene expression and reduce IL-1{beta} levels as pharmacodynamic markers of microglial activation and neuroinflammation in an amyloidosis mouse model of Alzheimers disease. Collectively, these results define a scaffold with SHIP1 target engagement, CNS exposure, and in vivo activity, providing a foundation for the optimization of brain-penetrant SHIP1 ligands suitable for further mechanistic studies and therapeutic development for the treatment of Alzheimers disease.

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Jesudason, C. D., Rangel-Barajas, C., Beach, C. J., Beck, D. E., Caballero-Floran, I. H., Clayton, W. B., Da Silva, L., David, J. C., Doolen, S., Faulkner, A. N., Hamdani, A. K., Huhe, H., Huynh, K., Imhoff, R. D., Javens-Wolfe, J., Mason, E. R., Moussaif, M., Singhal, K., Soni, D. M., Van Buuren-Milne, M., Williams, S.-P., Angus, S. P., Chu, S., Dage, J. L., Hipskind, P. A., Johnson, T. S., Kadurah-Dauok, R. F., Lamb, B. T., Meikle, P. J., Mesecar, A. D., Palkowitz, A. D., Quinney, S. K., Sukoff Rizzo, S. J., Oblak, A. L., Richardson, T. I.. 2026-01-02. Optimization and Characterization of SHIP1 Ligands for Cellular Target Engagement and Activity in Alzheimer's Disease Models. https://doi.org/10.64898/2025.12.31.697127

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