HNMT Knockout HAP1 Polyclonal Cells are a pooled population of HAP1 cells engineered via CRISPR/Cas9-mediated disruption of the HNMT gene, generating a heterogeneous knockout model for histamine N-methyltransferase deficiency. This polyclonal product contains diverse loss-of-function mutations, providing a robust system to study HNMT-dependent histamine inactivation without clonal bias.
The HAP1 cell line is a near-haploid derivative of KBM-7 chronic myeloid leukemia cells, serving as a hematopoietic malignancy model. Its haploid genome facilitates precise genetic manipulation and simplifies downstream analyses, making it a favored platform for functional genomics, drug screening, and pathway dissection.
HNMT is a cytosolic S-adenosylmethionine (SAM)-dependent methyltransferase that inactivates histamine by producing N-methylhistamine and S-adenosylhomocysteine (SAH). This reaction terminates signaling through histamine receptors (HRH1?C4) and is critical for histamine clearance in brain, epithelial, and immune tissues. HNMT activity is regulated by the glucocorticoid receptor (NR3C1), histamine substrate availability, and SAM levels, and it operates in concert with diamine oxidase (DAO) to control extracellular histamine. Downstream consequences of HNMT action include reduced histamine receptor activation and modulation of neurotransmitter and inflammatory pathways.
In HAP1 leukemic cells, HNMT knockout causes histamine accumulation, potentially altering histamine receptor?driven signaling that influences cell proliferation, apoptosis, and immune interactions. The near-haploid background reduces genetic redundancy, allowing clearer interpretation of histamine?mediated phenotypes and enabling screens for modifiers of histamine sensitivity or HNMT inhibitor efficacy.
This knockout model is applicable to histamine metabolism research, allergy and asthma studies, neuroinflammation modeling, and high?throughput screening of HNMT inhibitors. Compatible experimental approaches include histamine ELISA, HNMT activity assays, western blotting, RT?qPCR, calcium flux measurement, LC?MS?based quantification of histamine and N?methylhistamine, and cell viability assays under histamine challenge. For additional information, please contact Ascent Research.
