The HMOX1 Knockout MAC-T Cell Line is a CRISPR/Cas9-edited bovine mammary epithelial cell line engineered with a targeted disruption of the HMOX1 gene, which encodes heme oxygenase-1 (HO-1). This knockout cell line provides a stable loss-of-function model for investigating the enzyme??s cytoprotective, antioxidant, and anti-inflammatory functions within a physiologically relevant mammary epithelial context.
The parental MAC-T cell line is an immortalized yet non-transformed bovine mammary epithelial line derived from primary mammary alveolar cells. It retains responsiveness to lactogenic hormones and supports milk protein synthesis and secretion, making it a well-established model for lactation biology, mammary gland development, and dairy cattle health research. MAC-T cells exhibit polarized epithelial morphology and express caseins upon hormonal induction, faithfully recapitulating key features of the lactating mammary epithelium.
HMOX1 encodes heme oxygenase-1, which catalyzes the oxidative cleavage of heme into biliverdin, carbon monoxide (CO), and ferrous iron. Biliverdin is reduced by biliverdin reductase A to bilirubin, a key antioxidant. CO signals via soluble guanylyl cyclase to mediate anti-inflammatory effects, while ferrous iron induces ferritin, limiting oxidative damage. Transcriptional induction is driven by NRF2 (NFE2L2), which, under stress, dissociates from KEAP1 and translocates to the nucleus. Repression is mediated by Bach1 and MAF. Additional inputs from HIF1A, heat shock, heavy metals, and cytokines (IL-10, IL-1??) fine-tune expression. HO-1 activity modulates MAPK1/3 (ERK), AKT1 (PI3K-AKT), and NFKB1 (NF-??B) pathways, upregulating Bcl-2, p21, and VEGF. Interacting partners such as NADPH-cytochrome P450 reductase and p62/SQSTM1 contribute to enzyme function and NRF2 regulation.
In the mammary epithelium, high metabolic demands during lactation generate significant oxidative stress, and HO-1 is thought to protect cells by degrading pro-oxidant heme and generating antioxidant molecules. Additionally, its anti-inflammatory functions help restrain excessive immune responses that could compromise milk production or lead to mastitis. By disrupting HMOX1 in MAC-T cells, this knockout line enables studies on how loss of HO-1 affects mammary epithelial cell viability, redox homeostasis, and susceptibility to bacterial pathogens or inflammatory cytokines. It serves as a molecular tool for dissecting the interplay between oxidative stress, lactation, and mammary gland health.
Typical applications include ROS detection, cell viability assays under oxidative stress, bilirubin quantification, and RT-qPCR/Western blotting for NRF2 target genes. The line supports cytokine profiling by ELISA, immunofluorescence, and apoptosis flow cytometry. It is suitable for NRF2 activator screening and host-pathogen interaction studies modeling mastitis pathogens. Additional uses encompass cellular senescence research and analysis of HO-1??s role in mammary gland aging. For ordering, technical inquiries, or custom gene-editing services, contact Ascent Research.
