The HAVCR2 Knockout HK-2 Cell Line is a targeted loss-of-function model created by CRISPR/Cas9-mediated disruption of the HAVCR2 gene, which encodes the T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) receptor, in the immortalized human kidney proximal tubular epithelial cell line HK-2. This stable knockout cell line provides a consistent experimental tool for investigating TIM-3-dependent signaling and immune regulation in an epithelial context, circumventing the variability and transient nature of siRNA or lentiviral knockdown approaches.
HK-2 cells, derived from normal adult kidney cortex, retain proximal tubule-specific characteristics including brush border enzyme expression, solute transporter function, and polarized monolayer formation. They are widely utilized in nephrotoxicity testing, drug transporter assays, and studies of renal reabsorptive and secretory mechanisms. Importantly, HK-2 cells produce pro-inflammatory and immunomodulatory cytokines such as IL-6, IL-8, and TNF-??, and contribute to epithelial barrier integrity through tight junction proteins, making them a suitable host for examining the role of immune checkpoint molecules in kidney physiology and pathology.
HAVCR2 (TIM-3) functions as a type I transmembrane inhibitory receptor expressed on T cells, macrophages, dendritic cells, and certain epithelia. Its engagement by ligands galectin-9 (LGALS9), phosphatidylserine, HMGB1, and CEACAM1 triggers dissociation of the adaptor Bat3 and recruitment of the Src family kinase Fyn, leading to phosphorylation of intracellular tyrosine residues. This initiates signaling cascades that inhibit PI3K?CAKT?CmTOR and NF-??B pathways while promoting STAT3 activation, ultimately suppressing transcription of IL-2, IFN-??, granzyme B, perforin, FAS/FASL, and upregulating anti-apoptotic factors like Bcl-2. In non-T cells, TIM-3 modulates cytokine secretion and apoptotic cell clearance. In proximal tubular epithelial cells, HAVCR2 signaling may intersect with toll-like receptor and TGF-?? pathways to influence inflammatory gene expression and cell fate under stress.
Knockout of HAVCR2 in HK-2 cells eliminates the inhibitory checkpoint, potentially enhancing pro-inflammatory cytokine output, altering apoptosis susceptibility, and disrupting epithelial barrier function. This renders the line valuable for modeling acute kidney injury where TIM-3 engagement by damage-associated molecular patterns like HMGB1 or exposure to galectin-9 may exacerbate or attenuate tubular damage. The system permits separation of epithelial cell-autonomous functions from systemic immune effects, enabling detailed study of how TIM-3 loss influences proximal tubule responses to nephrotoxins, ischemia, or cytokine stimulation.
Research applications of this knockout line include co-culture setups with primary T cells or peripheral blood mononuclear cells to dissect juxtacrine signaling, phospho-kinase arrays to quantify AKT/mTOR/STAT3 activation, and ELISA or multiplex cytokine profiling of IL-6, TNF-?? and other mediators. Flow cytometry assays using Annexin V and propidium iodide can measure apoptosis following cisplatin or cyclosporine A challenge, while immunofluorescence imaging can evaluate tight junction integrity. The model supports RNA-seq studies to uncover HAVCR2-dependent transcriptional programs and is suitable for screening small molecule checkpoint modulators in a kidney-relevant context. For technical details or customization inquiries, please reach out to Ascent Research.
