APOH Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the near-haploid human HAP1 cell line, designed for functional disruption of the APOH gene encoding beta-2-glycoprotein I (??2GPI). This knockout model is generated by introducing targeted lesions into the APOH locus, resulting in a heterogeneous pool of cells with loss-of-function alleles. The polyclonal format preserves population-level diversity while eliminating wild-type expression, making it suitable for downstream applications where monoclonal isolation is not required. The product provides a robust system for investigating APOH-dependent processes in a human myeloid leukemia background.
HAP1 is a haploid myeloid leukemia cell line originating from the KBM-7 chronic myeloid leukemia (CML) model, characterized by its near-haploid karyotype except for a disomic region of chromosome 8. This genomic simplicity minimizes complications from diploid gene redundancy and facilitates unambiguous knockout studies. HAP1 cells retain expression of numerous signaling components relevant to innate immunity and thrombosis, including Toll-like receptors and annexin family members, enabling investigation of APOH-mediated pathways in a hematologic context. Their CML origin also offers a background to explore coagulation-related signaling in leukemic cells.
APOH encodes a phospholipid-binding plasma glycoprotein that functions as a critical cofactor for antiphospholipid antibodies and regulates coagulation and complement cascades. Transcription of APOH is regulated by HNF4A, C/EBP transcription factors, and the inflammatory cytokine IL-6. The ??2GPI protein interacts with negatively charged phospholipids such as cardiolipin, and forms complexes with cell surface receptors including Annexin A2, LRP8, TLR2, TLR4, and glycoprotein Ib??. Downstream, APOH engagement triggers MyD88-dependent NF-??B activation, AKT1 signaling, and integrin-mediated platelet responses, while also modulating factor XI and complement C3 activity. These interactions position APOH at the intersection of proinflammatory and prothrombotic signaling, with tissue factor (F3) representing a key representative pathway component. The mechanistic role of APOH thus involves both promoting endothelial and monocyte activation via TLR2/4?CAnnexin A2 complexes and inhibiting platelet prothrombinase activity to fine-tune coagulation.
Despite APOH??s predominant hepatic synthesis, HAP1 cells endogenously express several APOH-interacting partners, including Annexin A2, TLR2, and TLR4, making the knockout model valuable for dissecting cell-autonomous aspects of APOH signaling. Loss of APOH disrupts phospholipid-dependent receptor activation and downstream NF-??B and AKT1 pathways, allowing investigation of ??2GPI??s regulatory functions in a myeloid context. The near-haploid background simplifies allele editing and enhances reproducibility in functional assays, while the polyclonal pool avoids clonal artifacts. This model is particularly suited for studying APOH??s role in antiphospholipid antibody-mediated signaling and coagulation pathway crosstalk in leukemic cells.
Researchers can employ this knockout pool in a wide range of assays, including western blotting, ELISA, and dilute Russell viper venom time (dRVVT) assays to assess phospholipid-dependent coagulation. Flow cytometry and immunofluorescence enable monitoring of surface receptor expression, while NF-??B reporter assays quantify TLR-mediated transcriptional responses. Co-immunoprecipitation with Annexin A2 or TLR2 facilitates interaction studies, and phospho-signaling analysis reveals activation states of downstream effectors such as NF-??B and AKT1. RNA-seq provides transcriptomic insights into APOH-dependent gene networks. Primary applications span antiphospholipid syndrome research, thrombosis and autoimmune disease modeling, drug target validation for thrombotic disorders, and phospholipid-binding protein investigation. For technical inquiries or custom requests, please contact Ascent Research.
