Nyamugenda, E. | Search bioRxiv

bioRxiv2025

New Insights on Bridging Integrator 1 Protein Isoforms as a Risk Increasing Gene in Alzheimer's Disease

INTRODUCTIONGenome-wide association studies (GWAS) have identified Bridging Integrator 1 (BIN1) as the second-most significant genetic risk factor for Alzheimers disease (AD). We performed GWAS by proxy (GWAX) using UKBiobank and replicated this finding. However, the mechanism by which BIN1 impacts AD risk is largely unknown. METHODSTo address this, we first measured the expression of BIN1 isoforms in a human induced pluripotent stem cells (hiPSC) model and further evaluated whether the BIN1 risk loci associated with the expression of BIN1 isoforms in a Phase 2 AD clinical trial. RESULTSOur data indicated BIN1 isoform expression patterns associated with the differentiation of hiPSC into neurons or microglia and found the variant rs35103166 impacts the expression of the BIN1 microglia-specific isoforms. DISCUSSIONGiven the strong association with susceptibility to AD, exploring the mechanisms of BIN1 genetic variants and their impacts on cell-type specific expression could serve as a valuable resource for novel drug discovery. HighlightsO_LIBIN1 variants are significantly associated with AD risk in GWAX analysis from UKBB. C_LIO_LIBIN1 isoforms show a cell-type-specific expression pattern during hiPSC differentiation into neurons or microglia. C_LIO_LIBIN1 risk alleles associate with BIN1 isoform expression in a Phase 2 AD trial (NCT02880956). C_LI

neuroscience↗

bioRxiv2023

A genome-wide CRISPR screen supported by human genetics identifies the TNRC18 gene locus as a novel regulator of inflammatory signaling

Interleukin-1{beta} (IL-1{beta}) is dysregulated in many chronic inflammatory diseases, yet the genetic factors influencing IL-1{beta} production and signaling remain largely unknown. Myeloid-derived cells are the primary producers of IL-1{beta}, prompting a genome-wide CRISPR knockout screen in the human myeloid-derived U937 cell model, treated with lipopolysaccharide (LPS) to mimic inflammatory conditions, and sorted for high and low intracellular IL-1{beta} levels. A total of 295 genes were identified as regulators of IL-1{beta} production, including known mediators, such as TLR4, JAK-STAT, IL-10 receptor, and the Cullin ring finger ligase complex. Notably, 57 out of the 295 genes overlapped with loci associated with human inflammatory diseases, including the TNRC18 gene on chromosome 7p22.1 associated with multiple diseases in the Finnish population. U937 cells engineered with the homozygous rs748670681 risk allele associated with inflammatory bowel disease, demonstrated decreased levels of mRNA for TNRC18 and an adjacent gene WIPI2, reduction in LPS-dependent gene activation and cytokine production, but elevation of interferon-responsive gene programs. Transcriptomic profiles for individual knockouts of TNRC18 and WIPI2 attributed the loss of LPS-dependent signaling primarily to TNRC18 while the exacerbation of interferon signaling is a hallmark of loss of WIPI2. Collectively, these findings delineate the global regulatory mechanisms of IL-1{beta} production and provide molecular insights to the role of the rs748670681 variant as a pleiotropic risk factor for inflammatory diseases.

genomics↗