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FUJIFILM Cellular Dynamics Poster Presentation

Session: P092 | Presentation: P092.02
Presentation Time: Monday, Jan 11, 3:00 PM EST
Title: Generation of iPSC-derived TREM2 R47H and isogenic TREM2 Loss of Function (LOF) microglia to investigate Alzheimer’s disease risk
Authors: C. Munn, S. Burton, I. Gurevich, M. Goedland, M. McLachlan, M. Xong, D. Rajesh, S. Hilcove, W.W. Poon

Abstract: Recent Genome-wide association studies (GWAS) in Alzheimer’s disease (AD) have uncovered a number of single nucleotide polymorphisms (SNPs) or genetic variants within genes predominantly expressed in microglia in the CNS (TREM2, CD33, TYROBP, PLCG2).  Microglia are the resident immune cell of the brain, and numerous studies have linked genetic variants of triggering receptor expressed on myeloid cells 2 (TREM2), including the R47H variant, with impairment of microglia function affecting ligand binding/sensing, phagocytosis, metabolism, and inflammatory responses.  Since primary human microglia from living donors are not accessible for research, we generated microglia from episomally reprogrammed human induced pluripotent stem cells (iPSCs) from donors harboring either WT TREM2 or the R47H mutation.  In addition, end-stage microglia were generated from both heterozygous (TREM2 HT) and homozygous (TREM2 HO) TREM2 KO gene edited isogenic iPSCs derived from an apparently healthy normal (AHN) donor.  To generate a large batch of cryopreserved end-stage microglia, iPSCs were first differentiated to hematopoietic progenitor cells (HPCs) and purified by MACS of CD34+ cells (>90%). CD34+ isolated cells also expressed CD43, CD45, and CD235/CD31.  Next, HPCs were differentiated to pure end-stage microglia and cryopreserved.  Upon thaw, the microglia (i) retained a high purity based on CD45, CD11b, CD33, P2RY12, TREM2, CX3CR1, and IBA-1 expression, (ii) retained the ability to be polarized towards an inflammatory or anti-inflammatory subtype by specific stimuli, and (iii) are indistinguishable from freshly differentiated microglia.  This panel of iPSC-derived microglia expressing WT TREM2, TREM2 R47H, TREM2 HT, TREM2 HO was used to understand the role of TREM2 R47H or loss of function (LOF) of TREM2 in isogenic microglia on phagocytic function, cytokine response and whole transcriptome gene expression for predictive in vitro disease modeling applications.  This unique tool set of microglia is useful for interrogating the role of TREM2 function and for identification of compounds that restore TREM2 function in high throughput screening assays.  Thus, both patient-derived TREM2 R47H and isogenic variants of TREM2 LOF microglia are valuable platforms for investigating TREM2’s role in AD pathogenesis.