The Hspa5 Knockout RAW 264.7 Cell Line is a CRISPR/Cas9-edited mouse macrophage model with targeted disruption of the Hspa5 gene encoding the ER chaperone BiP/GRP78. This loss-of-function cell line facilitates dissection of Hspa5 roles in ER proteostasis, UPR signaling, and downstream stress responses. Derived from the well-characterized RAW 264.7 host, it provides a stable platform for reproducible experiments focused on the interplay between ER stress and macrophage function in innate immunity and disease.
The RAW 264.7 host cell line originates from BALB/c mice and was immortalized by Abelson murine leukemia virus. It retains macrophage hallmarks such as phagocytic activity, antigen presentation, and secretion of cytokines including TNF-?? and IL-6. Its well-documented responses to immune stimuli and genetic tractability render it an ideal platform for exploring how ER stress intersects with innate immune functions in a myeloid context.
Hspa5/BiP is a central ER chaperone that binds to IRE1??, PERK, and ATF6 under basal conditions, keeping the UPR inactive. ER stressors??tunicamycin, thapsigargin, hypoxia, glucose deprivation??promote BiP dissociation to engage misfolded proteins, triggering sensor activation. IRE1?? splices Xbp1 mRNA to generate XBP1s; PERK phosphorylates eIF2?? to induce ATF4; ATF6 is cleaved to an active transcription factor. These effectors upregulate ERAD components (SEL1L, HRD1) and, under severe stress, CHOP. BiP also modulates NF-??B signaling and cytokine production (TNF-??, IL-6), linking proteostasis to inflammation.
In macrophages, Hspa5 knockout ablates a critical control point of the UPR, disrupting the balance between adaptation and apoptosis. RAW 264.7 cells lacking BiP offer a clean system to study how unmitigated ER stress alters cytokine secretion, phagocytosis, and polarization, with implications for chronic inflammation and tumor-associated macrophage biology. This model allows dissection of individual UPR branch contributions??e.g., XBP1s and ATF4??to inflammatory gene programs, revealing the necessity of Hspa5 for proper innate immune responses and cellular viability under proteotoxic challenge.
This knockout line is suited for ER stress induction assays using pharmacological agents, followed by Western blot for BiP, CHOP, and phospho-eIF2??, XBP1 splicing analysis, apoptosis detection, and cytokine profiling. Applications span cancer biology, neurodegenerative disease, and diabetes research, elucidating how macrophage ER stress influences disease progression. It also supports drug screening to identify UPR modulators. For further details, please contact Ascent Research.
