Comparison of bone marrow-derived macrophages from BALB/c and C57BL/6 mice with and without interferon-gamma stimulation.. Mus musculus

ABSTRACT Macrophages are essential components of the innate immune system and crucial for pathogen elimination in early stages of infection. We previously observed that bone marrow-derived macrophages (BMM) from C57BL/6 mice exhibited increased killing activity against Burkholderia pseudomallei compared to BMM from BALB/c mice. This effect was particularly pronounced when cells were treated with IFN-γ. To unravel mechanisms that could explain these distinct bactericidal effects, a comparative combined proteome and transcriptome analysis of untreated and IFN-γ treated BALB/c and C57BL/6 BMM under standardized serum-free conditions was carried out. We found differences in gene expression/ protein abundance belonging to cellular oxidative and antioxidative stress systems. Genes/ proteins involved in the generation of oxidant molecules and the function of phagosomes (respiratory chain ATPase, lysosomal enzymes, cathepsin) were predominantly higher expressed/ more abundant in C57BL/6 BMM. Components involved in alleviation of oxidative stress (peroxiredoxin, mitochondrial superoxide dismutase) were more abundant in C57BL/6 BMM as well. Thus, C57BL/6 BMM seemed to be better equipped with cellular systems that may be advantageous in combating engulfed pathogens. Simultaneously, C57BL/6 BMM were well protected from oxidative burst. We assume that these variations co-determine differences in resistance between BALB/c and C57BL/6 mice observed in many infection models. Biological significance: In this study we performed combined transcriptome and proteome analyses on BMM derived from two inbred mouse strains that are frequently used for studies in the field of host-pathogen interaction research. Strain differences between BALB/c and C57BL/6 BMM were found to originate mainly from different protein abundance levels rather than from different gene expression. Differences in abundance of respiratory chain complexes and phagosomal proteins as well as differential regulation of components belonging to various antioxidant stress systems help to explain long-known differences between the mouse strains concerning their different susceptibility in several infection models. Overall design: In this study 12 samples were analyzed. They are classified into four groups: BMM of Balb/c mice medium control, BMM of Balb/c mice interferon gamma treated, BMM of C57Bl/6 mice medium control, and BMM of C57Bl/6 mice interferon gamma treated. Each of the four groups contains 3 biological replicates.