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Ramakrishnan GS, Berry WL, Pacherille A, Kerr WG, Chisholm JD, Pedicone C, Humphrey MB. SHIP inhibition mediates select TREM2-induced microglial functions. Mol Immunol 2024; 170:35-45. [PMID: 38613944 PMCID: PMC11097602 DOI: 10.1016/j.molimm.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/14/2024] [Accepted: 04/06/2024] [Indexed: 04/15/2024]
Abstract
Microglia play a pivotal role in the pathology of Alzheimer's Disease (AD), with the Triggering Receptor Expressed on Myeloid cells 2 (TREM2) central to their neuroprotective functions. The R47H variant of TREM2 has emerged as a significant genetic risk factor for AD, leading to a loss-of-function phenotype in mouse AD models. This study elucidates the roles of TREM2 in human microglia-like HMC3 cells and the regulation of these functions by SH2-containing inositol-5'-phosphatase 1 (SHIP1). Using stable cell lines expressing wild-type TREM2, the R47H variant, and TREM2-deficient lines, we found that functional TREM2 is essential for the phagocytosis of Aβ, lysosomal capacity, and mitochondrial activity. Notably, the R47H variant displayed increased phagocytic activity towards apoptotic neurons. Introducing SHIP1, known to modulate TREM2 signaling in other cells, revealed its role as a negative regulator of these TREM2-mediated functions. Moreover, pharmacological inhibition of both SHIP1 and its isoform SHIP2 amplified Aβ phagocytosis and lysosomal capacity, independently of TREM2 or SHIP1 expression, suggesting a potential regulatory role for SHIP2 in these functions. The absence of TREM2, combined with the presence of both SHIP isoforms, suppressed mitochondrial activity. However, pan-SHIP1/2 inhibition enhanced mitochondrial function in these cells. In summary, our findings offer a deeper understanding of the relationship between TREM2 variants and SHIP1 in microglial functions, and emphasize the therapeutic potential of targeting the TREM2 and SHIP1 pathways in microglia for neurodegenerative diseases.
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Affiliation(s)
- Gautham S Ramakrishnan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - William L Berry
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Stephenson Cancer Center, Oklahoma City, OK, USA
| | | | - William G Kerr
- Department of Chemistry, Syracuse University, Syracuse, NY, USA; Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA; Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY, USA
| | - John D Chisholm
- Department of Chemistry, Syracuse University, Syracuse, NY, USA
| | - Chiara Pedicone
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mary Beth Humphrey
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma City Veteran's Affairs Medical Center, Oklahoma City, OK, USA.
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Yeoh WJ, Krebs P. SHIP1 and its role for innate immune regulation-Novel targets for immunotherapy. Eur J Immunol 2023; 53:e2350446. [PMID: 37742135 DOI: 10.1002/eji.202350446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/03/2023] [Accepted: 09/21/2023] [Indexed: 09/25/2023]
Abstract
Phosphoinositide-3-kinase/AKT (PI3K/AKT) signaling plays key roles in the regulation of cellular activity in both health and disease. In immune cells, this PI3K/AKT pathway is critically regulated by the phosphoinositide phosphatase SHIP1, which has been reported to modulate the function of most immune subsets. In this review, we summarize our current knowledge of SHIP1 with a focus on innate immune cells, where we reflect on the most pertinent aspects described in the current literature. We also present several small-molecule agonists and antagonists of SHIP1 developed over the last two decades, which have led to improved outcomes in several preclinical models of disease. We outline these promising findings and put them in relation to human diseases with unmet medical needs, where we discuss the most attractive targets for immune therapies based on SHIP1 modulation.
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Affiliation(s)
- Wen Jie Yeoh
- Institute of Tissue Medicine and Pathology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Philippe Krebs
- Institute of Tissue Medicine and Pathology, University of Bern, Bern, Switzerland
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Ehm PAH, Linnebacher M, Block A, Rehbach C, Jücker M. Targeted hyperactivation of AKT through inhibition of ectopic expressed SHIP1 induces cell death in colon carcinoma cells and derived metastases. Cell Signal 2023; 108:110720. [PMID: 37207939 DOI: 10.1016/j.cellsig.2023.110720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/14/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023]
Abstract
Current therapeutic approaches for colorectal cancer (CRC) focus on the suppression of oncogenic kinase signaling. Here, we test the hypothesis that targeted hyperactivation of the PI3K/AKT-signaling may lead to trigger CRC cell death. Recently we found that hematopoietic SHIP1 is ectopically expressed in CRC cells. Here we show that SHIP1 is more strongly expressed in metastatic cells than in the primary cancer cells, which allows for an increase in AKT signaling in metastatic cells, giving them an advantage from an evolutionary point of view. Mechanistically, the increased SHIP1 expression reduces the activation of the PI3K/ AKT signaling to a value that is below the threshold that leads to cell death. This mechanism gives the cell a selection advantage. We show that genetic hyperactivation of PI3K/AKT-signaling or blocking the activity of the inhibitory phosphatase SHIP1, induces acute cell death in CRC cells, because of excessive accumulation of reactive oxygen species. Our results demonstrate that CRC cells critically depend on mechanisms to fine-tune PI3K/AKT activity and show SHIP1 inhibition as an unexpectedly promising concept for CRC therapy.
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Affiliation(s)
- Patrick A H Ehm
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
| | - Michael Linnebacher
- Molecular Oncology and Immunotherapy, Clinic of General, Thoracic, Vascular and Transplantation Surgery, University of Rostock, Rostock, Germany
| | - Andreas Block
- Department of Oncology, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Christoph Rehbach
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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