Comparison of Macrophage Immune Responses and Metabolic Reprogramming in Smooth and Rough Variant Infections of <i>Mycobacterium mucogenicum</i>
<i>Mycobacterium mucogenicum</i> (<i>Mmuc</i>), a rapidly growing nontuberculous mycobacterium (NTM), can infect humans (posttraumatic wound infections and catheter-related sepsis). Similar to other NTM species, <i>Mmuc</i> exhibits colony morphologies of rough (&...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-02-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/5/2488 |
| Summary: | <i>Mycobacterium mucogenicum</i> (<i>Mmuc</i>), a rapidly growing nontuberculous mycobacterium (NTM), can infect humans (posttraumatic wound infections and catheter-related sepsis). Similar to other NTM species, <i>Mmuc</i> exhibits colony morphologies of rough (<i>Mmuc</i>-R) and smooth (<i>Mmuc</i>-S) types. Although there are several case reports on <i>Mmuc</i> infection, no experimental evidence supports that the R-type is more virulent. In addition, the immune response and metabolic reprogramming of <i>Mmuc</i> have not been studied on the basis of morphological characteristics. Thus, a standard ATCC <i>Mmuc</i> strain and two clinical strains were analyzed, and macrophages were generated from mouse bone marrow. Cytokines and cell death were measured by ELISA and FACS, respectively. Mitochondrial respiration and glycolytic changes were measured by XF seahorse. Higher numbers of intracellular bacteria were found in <i>Mmuc</i>-R-infected macrophages than in <i>Mmuc</i>-S-infected macrophages. Additionally, <i>Mmuc</i>-R induced higher levels of the cytokines TNF-α, IL-6, IL-12p40, and IL-10 and induced more BMDM necrotic death. Furthermore, our metabolic data showed marked glycolytic and respiratory differences between the control and each type of <i>Mmuc</i> infection, and changes in these parameters significantly promoted glucose metabolism, extracellular acidification, and oxygen consumption in BMDMs. In conclusion, at least in the strains we tested, <i>Mmuc</i>-R is more virulent, induces a stronger immune response, and shifts bioenergetic metabolism more extensively than the S-type. This study is the first to report differential immune responses and metabolic reprogramming after <i>Mmuc</i> infection and might provide a fundamental basis for additional studies on <i>Mmuc</i> pathogenesis. |
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| ISSN: | 1661-6596 1422-0067 |