Mass spectrometry-based proteomic exploration of diverse murine macrophage cellular models

Immortalised cell lines analogous to their primary cell counterparts are fundamental to research, particularly when large cell numbers are required. Here we report that immortalisation of bone marrow-derived macrophages using the J2-virus resulted in the loss of a protein of interest, MSR1, in wild-type cells by an unknown mechanism. This led us to perform an in-depth mass spectrometry-based proteomic characterisation of common murine macrophage cell lines (J774A.1, RAW264.7, and BMA3.1A7), with comparison to the immortalised bone marrow-derived macrophages (iBMDMs), as well as primary BMDMs. This revealed striking differences in protein profiles associated with macrophage polarisation, phagocytosis, pathogen recognition, and IFN signalling. J774A.1 cells were determined to be the most similar to the gold standard primary BMDM model, with BMA3.1A7 cells the least similar due to the reduction in abundance of several proteins related closely to macrophage function. This comprehensive proteomic data offers valuable insights into the selection of specific macrophage cell lines for cell signalling and inflammation research.