Comparative genotypic and phenotypic analysis of human peripheral blood monocytes and surrogate monocyte-like cell lines commonly used in metabolic disease research

• Published in: PloS one Vol. 13; no. 5; p. e0197177
• Main Authors: Riddy, Darren M, Goy, Emily, Delerive, Philippe, Summers, Roger J, Sexton, Patrick M, Langmead, Christopher J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.05.2018; Public Library of Science (PLoS)
• Subjects: Analysis; Biology; Biology and Life Sciences; Biotechnology; Blood; Cell lines; Cell surface; Chemokines; Chemotactic factors; Cytokines; Dendritic cells; Diabetes; Diabetes mellitus; Differentiation; Gene expression; Genes; Genetic engineering; Genotype & phenotype; Genotypes; Granulocyte-macrophage colony-stimulating factor; Growth factors; Immunology; Inflammation; Insulin resistance; Leukocyte migration; Leukocytes (mononuclear); Markers; Medicine and Health Sciences; Metabolic disorders; Metabolism; Monocyte chemoattractant protein 1; Monocytes; Pathogenesis; Peripheral blood mononuclear cells; Pharmaceutical sciences; Phenotypes; Phorbol esters; R&D; Research & development; Ribonucleic acid; RNA; Tryptophan; Tryptophan 2,3-dioxygenase; Australia; Victoria Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0197177

Monocyte-like cell lines (MCLCs), including THP-1, HL-60 and U-937 cells, are used routinely as surrogates for isolated human peripheral blood mononuclear cells (PBMCs). To systematically evaluate these immortalised cells and PBMCs as model systems to study inflammation relevant to the pathogenesis of type II diabetes and immuno-metabolism, we compared mRNA expression of inflammation-relevant genes, cell surface expression of cluster of differentiation (CD) markers, and chemotactic responses to inflammatory stimuli. Messenger RNA expression analysis suggested most genes were present at similar levels across all undifferentiated cells, though notably, IDO1, which encodes for indoleamine 2,3-dioxygenase and catabolises tryptophan to kynureninase (shown to be elevated in serum from diabetic patients), was not expressed in any PMA-treated MCLC, but present in GM-CSF-treated PBMCs. There was little overall difference in the pattern of expression of CD markers across all cells, though absolute expression levels varied considerably and the correlation between MCLCs and PBMCs was improved upon MCLC differentiation. Functionally, THP-1 and PBMCs migrated in response to chemoattractants in a transwell assay, with varying sensitivity to MCP-1, MIP-1α and LTB-4. However, despite similar gene and CD expression profiles, U-937 cells were functionally impaired as no migration was observed to any chemoattractant. Our analysis reveals that the MCLCs examined only partly replicate the genotypic and phenotypic properties of human PBMCs. To overcome such issues a universal differentiation protocol should be implemented for these cell lines, similar to those already used with isolated monocytes. Although not perfect, in our hands the THP-1 cells represent the closest, simplified surrogate model of PBMCs for study of inflammatory cell migration.