Comparative evaluation ofin vitrohuman macrophage models for mycobacterial infection study

Abstract

Macrophages are phagocytic cells that play a key role maintaining the homeostasis of many tissues. Their function is essential for controlling and eradicating infecting mycobacteria. Human monocytic cell lines such as THP-1 and U937 have provided interesting insights into how mycobacteria subvert the host cell response. However, immortalized cell lines could bring some disadvantages. Here we compare the response of THP-1 and U937 cell lines with human monocyte-derived macrophages (hMDMs) to determine functional differences during infection with different mycobacterial phenotypes (virulent Mycobacterium tuberculosis H37Rv and Mycobacterium bovis, and attenuated M. bovis BCG). The findings of this study indicate that the U937 cell line displays a significantly lower phagocytic capacity than hMDMs and THP-1 macrophages, regardless of the mycobacterial strain. In all cell models, interferon-γ activation leads to up-regulation of interleukin-12 and nitrite production. However, the phorbol 12-myristate 13-acetate (PMA)-induced differentiation of U937 and THP-1 cell lines induces a significant tumor necrosis factor-α production in resting macrophages. However, this state of activation has no effect on the control of intracellular growth of mycobacteria. Moreover, U937 cells show more discrepancies with hMDM than THP-1. This study demonstrates that THP-1 macrophages exhibit closer functional similarities to hMDMs in response to mycobacterial infection, regardless of the strain.

NAD+ Depletion Triggers Macrophage Necroptosis, a Cell Death Pathway Exploited by Mycobacterium tuberculosis

“…To examine the molecular mechanism of TNT-induced cell death, we used the human macrophage cell line THP-1 as an infection model (Mendoza-Coronel and Castañón-Arreola, 2016; Riendeau and Kornfeld, 2003). Mtb strains (Table S1) secreting functional TNT replicated and increased cell numbers by 10- to 30-fold after 3–5 days, whereas the Δ cpnT deletion mutant did not replicate and was slowly killed (Figure 1A).…”

Mycobacterium tuberculosis Infection and Innate Responses in a New Model of Lung Alveolar Macrophages

“…Immortalized cell lines are routinely used due to their availability in large scale, but they often originate from tumors and/or were obtained through multiple passages; thus, their genetic background is not well defined and their phenotype can vary between lots. As such, they may not always be appropriate models to understand tissue-specific cellular functions ( 12 , 13 ), or to correctly summarize critical interactions with pathogens, as reported in the case of Leishmania ( 14 ), adeno-associated virus ( 15 ), and Mtb ( 16 , 17 ). In this context, the large-scale availability of MPI cells as a primary cellular model mimicking lung AMs could open new prospects in the understanding of pulmonary diseases, notably those involving complex host-pathogen interactions like TB.…”

Primary macrophages and J774 cells respond differently to infection with Mycobacterium tuberculosis

“…Several macrophage models have been used to study M. tuberculosis infection. These include primary macrophages, mainly human monocyte-derived macrophages (hMDMs) or mouse bone marrow-derived macrophages (BMDMs); and cell lines, such as the human THP-1 and U937, or the murine J774 and RAW 264.7 4 5 . BMDMs are a useful model because they can be easily cultured and expanded to large numbers.…”

“…Previous comparisons of macrophage infection models for M. tuberculosis have focused on certain phenotypic traits such as intracellular growth, cytokine production, or phagosome characteristics 5 9 10 . Jordao and collaborators found that Mycobacterium bovis grows more efficiently in hMDMs than in J774 over a 7-day time course, even though both types of macrophages can restrict growth during the first 24 hours of infection through a mechanism involving phagosome acidification and nitric oxide production 9 .…”