Biology subjects

Neyrolles, O.

Publications and source records attributed to Neyrolles, O..

At least 19 recordsLinked to original sources

bioRxiv2026

CysK2 couples copper sensing to metabolic and redox adaptation in Mycobacterium tuberculosis

Copper is increasingly recognized as a host-derived cue encountered by Mycobacterium tuberculosis and other microbes during infections, yet the magnitude, intracellular distribution, and physiological consequences of this exposure remain incompletely understood. Here, we combined high-resolution imaging, transcriptomic profiling, intracellular reporter assays, isotope tracing, and mouse infection models to define how M. tuberculosis responds to physiologically relevant copper levels during macrophage infection. NanoSIMS analysis showed that copper reaches intracellular bacilli and accumulates in discrete phosphorus-rich foci in bacteria. Exposure to physiological copper concentrations in vitro triggered a highly specific transcriptional response dominated by the copper-inducible CsoR and RicR regulons. The RicR-regulated gene cysK2 gene, encoding the S-sulfocysteine synthase CysK2, was one of the most strongly induced loci. In infected macrophages, cysK2 expression was modulated by extracellular copper availability, host copper transport pathways, and hypoxia. In vitro, an H37Rv cysK2-deficient mutant showed reduced amino acid biosynthesis in response to copper exposure. In vivo, the mutant was impaired in long-term persistence in mice and displayed a higher oxidation status. Together, these findings identify CysK2 as a copper-responsive metabolic effector that couples host-derived copper sensing to redox homeostasis and intracellular adaptation in M. tuberculosis. IMPORTANCESuccessful infection by Mycobacterium tuberculosis depends on its ability to detect and adapt to host-imposed changes in the phagosomal environment. Our work shows that copper contributes to this adaptation not simply by imposing toxicity, but by triggering a metabolic response that helps sustain bacterial fitness within host cells. We identify CysK2 as a key component of this response, linking copper sensing to sulfur metabolism, redox balance, and persistence during infection. These findings shift the view of copper from a purely antimicrobial factor to a host-derived environmental signal that remodels M. tuberculosis physiology, and they uncover a new mechanism by which the pathogen maintains intracellular survival.

microbiology↗

bioRxiv2026

ST8SIA4-mediated polysialylation is critical for CCR2-driven monocyte egress from the bone marrow

Polysialylation is a rare post-translational protein modification essential for brain development and synaptic plasticity, where it fine-tunes cell-cell and cell-matrix interactions to direct neuronal migration, neurite outgrowth and synaptogenesis. Although polysialic acid is also expressed on circulating leukocytes, its functions in the immune system remain largely unexplored. Guided by analysis of publicly available human genomic data showing that naturally occurring variants of ST8SIA4, which encodes one of the two enzymes that mediate polysialylation, associate with reduced circulating monocyte counts, we investigated the in vivo role of this enzyme in monocyte biology. Using St8sia4-deficient mice, we show that ST8SIA4-dependent polysialylation is essential for CCR2-mediated egress of inflammatory monocytes from the bone marrow at steady state and during Mycobacterium tuberculosis infection. We confirm NCAM1 as the principal polysialylated protein in inflammatory monocytes and demonstrate that Ncam1-deficient mice phenocopy the monocyte defects observed in St8sia4-deficient animals. Mechanistically, loss of ST8SIA4-dependent polysialylation impairs engagement and internalization of the CCR2 ligands CCL2 and CCL7, accompanied by disrupted CCR2 surface organization and extensive cytoskeletal remodeling. Together, these findings identify polysialylation as a previously unrecognized regulator of CCR2 function and monocyte mobilization, with broad implications for immune surveillance and inflammatory responses. Highlights- Human ST8SIA4 variants are associated with reduced blood monocyte and lymphocyte counts and increased risk of SLE. - St8sia4-/- mice exhibit monocytopenia with impaired CCR2-mediated egress of inflammatory monocytes from the bone marrow both at steady state and during Mycobacterium tuberculosis infection. - ST8SIA4 polysialylates NCAM1 (CD56) in inflammatory monocytes, and Ncam1-/- - mice phenocopy the monocytopenia observed in St8sia4-/- mice. - Loss of ST8SIA4 and polysialylation impairs CCR2-mediated binding and endocytosis of CCL2 and CCL7 by monocytes. - Polysialic acid itself does not function as a co-receptor for these chemokines, revealing a new paradigm for its role in immune cell trafficking. - Proper CCR2 surface distribution and function, as well as cytoskeletal organization in inflammatory monocytes, depend on ST8SIA4-mediated polysialylation.

immunology↗

bioRxiv2025

SP140 limits type I interferon-driven pathology, preserving T cell motility and promoting resistance in tuberculosis

CD8+ T cells are elicited during tuberculosis yet how susceptible lung environments shape their maintenance and behavior is unclear. We examined pulmonary T cell responses to Mycobacterium tuberculosis in resistant control and Sp140-/- mice, a model of type I interferon (IFN-I)-driven susceptibility. Resistant mice generated diverse CD8+ effector- and memory-like subsets producing TNF and IFN{gamma}, whereas Sp140-/- mice showed a broad loss of pulmonary CD8+ T cells. Single-cell RNA sequencing revealed altered states in CD8+ T cells from susceptible mice with exhaustion and IFN-I transcriptional programs. IFNAR blockade rescued CD8+ T cell numbers, diversity, cytokine production, reduced bacterial burden and lung pathology, with comparable benefits also valid for CD4+ T cells. Intravital microscopy of infected lungs further showed that T cell dynamics and motility within lesions were restricted under exuberant IFN-I signaling but fully restored by IFNAR blockade. Thus, IFN-I-driven tissue pathology restricts T cell accumulation and motility during tuberculosis. TeaserIn tuberculosis, excessive type I interferon signaling reshapes the lung environment, limiting T cell accumulation and motility within infected lesions.

immunology↗

bioRxiv2025

Dual human lung models reveal compartment-specific activity of anti-tuberculosis drugs and host-directed therapies

Tuberculosis (TB) remains a major global health challenge that requires new therapeutic strategies to improve drug efficacy, shorten treatment duration, prevent drug resistance, and limit Mycobacterium tuberculosis (Mtb) persistence. Here, we established complementary in vitro human lung models integrating alveolar macrophage-like (AML) cells and airway air-liquid interface (ALI) cultures to evaluate standard-of-care antibiotics, host-directed therapies, and virulence-targeting agents. AMLs recapitulated key morphological, transcriptional, and functional features of primary alveolar macrophages, including a CD16+ immunoregulatory phenotype highly permissive to Mtb infection. In parallel, ALI cultures maintained epithelial barrier integrity and secretory functions, allowing apical Mtb infection, drug penetration analysis, and inflammatory profiling. Benchmarking of standard-of-care antibiotics revealed compartment-specific activity: isoniazid, rifampicin, and moxifloxacin were effective in both systems, while pyrazinamide was active only in AMLs. Anti-inflammatory host-directed therapies such as ibuprofen and doramapimod selectively reduced cytokine production without affecting bacterial load. Together, this dual-platform system offers a physiologically relevant and scalable model to assess antimicrobial efficacy and host modulation across distinct pulmonary niches, bridging the gap between conventional macrophage assays and the complex human lung.

immunology↗

bioRxiv2025

Lipid-mediated GPR32 signaling reprograms macrophage metabolism to impair anti-tuberculous immunity

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), has evolved strategies to evade innate immunity and establish persistent infection. However, the mechanisms by which M. tuberculosis reprograms human macrophage metabolism remain incompletely defined. Tuberculous pleural effusion (TB-PE), a common extrapulmonary manifestation that frequently coexists with pulmonary TB, offers a unique, clinically relevant immunometabolic window into the TB microenvironment. Here, using patient-derived TB-PE samples, we demonstrate that this microenvironment induces a metabolic state in human macrophages that compromises their antimicrobial function. Lipidomic analysis identified an enrichment of the specialized pro-resolving mediator Resolvin D5 (RvD5), which signals through GPR32 to suppress macrophage microbicidal activity. The acellular fraction of TB-PE was sufficient to induce RvD5 secretion by monocytes, correlating with increased expression of RvD5 biosynthetic enzymes in pleural monocytes from TB patients. Mechanistically, RvD5-GPR32 signaling inhibited glycolysis without promoting oxidative phosphorylation, reducing HIF-1 activity and impairing intracellular M. tuberculosis control. HIF-1 stabilization restored antimicrobial function. These findings uncover the RvD5-GPR32-HIF-1 axis as a mechanism of metabolic immune suppression and a potential target for host-directed TB therapy. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/663524v3_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@64feceorg.highwire.dtl.DTLVardef@948ab0org.highwire.dtl.DTLVardef@1d387forg.highwire.dtl.DTLVardef@682f72_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

HIV-1 Tat favors the multiplication of Mycobacterium tuberculosis and toxoplasma by inhibiting clathrin-mediated endocytosis and autophagy

AbstractHIV-1 and Mycobacterium tuberculosis (Mtb) coinfections are a major public health problem but are not well characterized. HIV-1 Tat is secreted by infected cells, generating nanomolar concentrations of Tat in the sera of people living with HIV. Circulating Tat enters cells, binds to PI(4,5)P2 then undergoes palmitoylation, thereby becoming resident on this phosphoinositide. Here, we found that Tat favors the multiplication of Mtb in macrophages. Moreover, Tat renders zebrafish larvae more sensitive to mycobacterial infection. We found that Tat binding to PI(4,5)P2 and palmitoylation enable Tat to inhibit the recruitment of the AP-2 adaptor, thereby inhibiting clathrin-mediated endocytosis and in turn autophagy. This inhibition prevents the degradation of intracellular pathogens such as Mtb and opsonized Toxoplasma gondii, but also of lipid droplets, thereby facilitating the access of these pathogens to lipids. We thus identified a mechanism enabling HIV Tat to favor the multiplication of intracellular pathogens such as Mtb.

microbiology↗

bioRxiv2025

PacL-organized membrane-associated effluxosomes coordinate multi-metal resistance in Mycobacterium tuberculosis

Metal ion homeostasis is crucial for bacterial pathogens to withstand metal-induced stress during infection. However, the mechanisms underlying bacterial resistance to metal stress remain incompletely understood, particularly how bacteria coordinate responses to simultaneous exposure to multiple metals. Here, we uncover a previously unrecognized mechanism by which Mycobacterium tuberculosis, the causative agent of tuberculosis, orchestrates a coordinated response to multi-metal stress. We demonstrate that M. tuberculosis assembles dynamic, membrane-associated platforms, organized by PacL proteins, that confer resistance to multiple metals simultaneously. PacL proteins function as scaffolds, clustering multiple P-type ATPase (P-ATPase) pumps, CtpC, CtpG, and CtpV, into functional complexes we term "effluxosomes". Our findings show that PacL proteins are critical for stabilizing CtpG within membrane-associated clusters, conferring cadmium tolerance, while CtpC serves as a backup, promoting cross-resistance to both zinc and cadmium. Using super-resolution microscopy and single-particle tracking, we elucidate the 3D structure and dynamics of effluxosomes in the mycobacterial membrane. We further demonstrate that conserved residues within the transmembrane domain of PacL proteins are crucial for the assembly of dynamic effluxosomes, which are essential for P-ATPase activity. Additionally, we reveal that PacL1 exhibits metallochaperone activity, binding zinc, cadmium, and copper via a conserved C-terminal motif. Proximity labeling further identifies an extensive PacL1 interaction network, encompassing multiple proteins involved in stress adaptation. Our findings introduce effluxosomes as dynamic, membrane-associated efflux machineries that mediate coordinated multi-metal resistance in M. tuberculosis, providing new insights into bacterial metal homeostasis and unveiling potential antimicrobial targets.

microbiology↗

bioRxiv2025

Identification of a unique TUBB3+ cell population in the tuberculosis granuloma

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading cause of mortality worldwide. Granulomas, hallmark structures of TB in the lungs and other infected tissues, are critical sites of host-pathogen interactions, yet their full cellular composition is not completely understood. Here, we identify a previously unrecognized {beta}3-tubulin (TUBB3)-positive cell population within TB granulomas in mice, guinea pigs, non-human primates, and TB patients. TUBB3 is a well-established pan-neuronal marker, yet these TUBB3+ cells are distinct from typical pulmonary resident cells and leukocytes. They exhibit a branched, elongated morphology, which is suggestive of neuron-like features. Intriguingly, their appearance is independent of adaptive immunity and is also observed in viral and fungal infections, but not in asthma. Our findings suggest the existence of a neuro-immune component within granulomas that may influence TB pathogenesis. Further investigation into the origin, function, and signaling pathways of these TUBB3+ cells is required to clarify their identity and potential role in host defense, which could reveal novel therapeutic targets for TB and other pulmonary infections.

immunology↗

bioRxiv2024

Inhibition of glycolysis in tuberculosis-mediated metabolic rewiring reduces HIV-1 spread across macrophages

Tuberculosis (TB) is a significant aggravating factor in individuals living with human immunodeficiency virus type 1 (HIV-1), the causative agent for acquired immunodeficiency syndrome (AIDS). Both Mycobacterium tuberculosis (Mtb), the bacterium responsible for TB, and HIV-1 target macrophages. Understanding how Mtb subverts these cells may facilitate the identification of new druggable targets. Here, we explored how TB can induce macrophages to form tunneling nanotubes (TNT), promoting HIV-1 spread. We found that TB triggers metabolic rewiring of macrophages, increasing their glycolytic ATP production. Using pharmacological inhibitors and glucose deprivation, we discovered that disrupting aerobic glycolysis significantly reduces HIV-1 exacerbation in these macrophages. Glycolysis is essential for tunneling nanotubes (TNT) formation, which facilitates viral transfer and cell-to-cell fusion and induces the expression of the sialoadhesin Siglec-1, enhancing both HIV-1 binding and TNT stabilization. Glycolysis did not exacerbate HIV-1 infection when TNT formation was pharmacologically prevented, indicating that higher metabolic activity is not sufficient per se to make macrophages more susceptible to HIV-1. Overall, these data might facilitate the development of targeted therapies aimed at inhibiting glycolytic activity in TB-induced immunomodulatory macrophages to ultimately halt HIV-1 dissemination in co-infected patients.

immunology↗

bioRxiv2024

The human and mouse dendritic cell receptor DCIR binds to LRP1 N-glycans containing terminal galactoses, including the α-Gal antigen

The dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor expressed by myeloid cells that plays a key immunoregulatory role in a wide range of diseases, from inflammation to cancer. However, the ligand(s) of DCIR remain(s) unknown, hampering our understanding of the exact function of this immune receptor. Here, we found that both human DCIR and mouse DCIR1 bind specifically to the low-density lipoprotein receptor-related protein 1 (LRP1), a heavily glycosylated receptor mediating the clearance of various molecules from the extracellular matrix and apoptotic cells. This interaction is mediated by galactose-terminated biantennary complex-type N-glycans, including those carrying the immunogenic -Gal epitope. Our study provides a deeper understanding of the role of DCIR in immune regulation and its potential impact on a range of immune disorders, highlighting its specificity in ligand recognition which is crucial for developing therapeutic strategies.

immunology↗

bioRxiv2023

Maintenance of cell wall remodeling and vesicle production are connected in Mycobacterium tuberculosis

Pathogenic and nonpathogenic mycobacteria secrete extracellular vesicles (EVs) under various conditions. EVs produced by Mycobacterium tuberculosis (Mtb) have raised significant interest for their potential in cell communication, nutrient acquisition, and immune evasion. However, the relevance of vesicle secretion during tuberculosis infection remains unknown due to the limited understanding of mycobacterial vesicle biogenesis. We have previously shown that a transposon mutant in the LCP-related gene virR (virRmut) manifested a strong attenuated phenotype during experimental macrophage and murine infections, concomitant to enhanced vesicle release. In this study, we aimed to understand the role of VirR in the vesicle production process in Mtb. We employ genetic, transcriptional, proteomics, ultrastructural and biochemical methods to investigate the underlying processes explaining the enhanced vesiculogenesis phenomenon observed in the virRmut. Our results establish that VirR is critical to sustain proper cell permeability via regulation of cell envelope remodeling possibly through the interaction with similar cell envelope proteins, which control the link between peptidoglycan and arabinogalactan. These findings advance our understanding of mycobacterial extracellular vesicle biogenesis and suggest that these set of proteins could be attractive targets for therapeutic intervention.

microbiology↗

bioRxiv2023

Glycolytic imprinting of monocytes impairs HIF1α-driven migration of dendritic cells in tuberculosis

During tuberculosis, migration of dendritic cells (DCs) from the site of infection to the draining lymph nodes is known to be impaired, hindering the rapid development of protective T-cell mediated immunity. However, the mechanisms involved in the delayed migration of DCs during tuberculosis (TB) are still poorly defined. Here, we found that infection of DCs with Mycobacterium tuberculosis (Mtb) triggers HIF-1-mediated aerobic glycolysis in a TLR2-dependent manner, and that this metabolic profile is essential for DC migration. In particular, the lactate dehydrogenase (LDH) inhibitor oxamate and the HIF-1 inhibitor PX-478 abrogated Mtb-induced DC migration in vitro to the lymphoid tissue-specific chemokine CCL21, and in vivo to lymph nodes in mice. Strikingly, we found that although monocytes from TB patients are inherently biased toward glycolysis metabolism, they differentiate into poorly glycolytic and poorly migratory DCs, compared with healthy subjects. Taken together, these data suggest that because of their preexisting glycolytic state, circulating monocytes from TB patients are refractory to differentiation into migratory DCs, which may explain the delayed migration of these cells during the disease and opens avenues for host-directed therapies for TB. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/535400v6_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@9c6849org.highwire.dtl.DTLVardef@82981dorg.highwire.dtl.DTLVardef@1d0b7faorg.highwire.dtl.DTLVardef@1deb76f_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2021

Mycobacterial resistance to zinc poisoning requires assembly of P-ATPase-containing membrane metal efflux platforms

Transition metals are toxic at high concentrations. The P1B-ATPase metal exporter CtpC/Rv3270 is required for resistance to zinc poisoning in the human pathogen Mycobacterium tuberculosis. Here, we discovered that zinc resistance also depends on the chaperone-like protein PacL1/Rv3269. PacL1 bound Zn2+, but unlike PacL1 and CtpC, the PacL1 metal-binding motif (MBM) was required only at high zinc concentrations. PacL1 co-localized with CtpC in dynamic microdomains within the mycobacterial plasma membrane. Microdomain formation did not require flotillins nor the PacL1 MBM. Instead, loss of the PacL1 Glutamine/Alanine repeats led to loss of CtpC and sensitivity to zinc. PacL1 and CtpC are within the same operon, and homologous PacL1-P1B-ATPase pairs are widely distributed within and across prokaryotes. PacL1 colocalized and functioned redundantly with PacL orthologs in Mycobacterium tuberculosis. Overall, our study suggests that PacL proteins are scaffolds that assemble P-ATPase-containing metal efflux platforms, a novel type of functional membrane microdomain that underlies bacterial resistance to metal poisoning.

microbiology↗

bioRxiv2021

Metabolic control of type 2 innate lymphoid cells plasticity toward protective type 1-like cells during Mycobacterium tuberculosis infection

Tissue-resident innate lymphoid cells (ILCs) regulate tissue homeostasis, protect against pathogens at mucosal surfaces and are key players at the interface of innate and adaptive immunity. How ILCs adapt their phenotype and function to environmental cues within tissues remains to be fully understood. Here, we show that Mycobacterium tuberculosis infection alters the phenotype and function of immature lung ILC2 toward a protective interferon-{gamma}-producing ILC1-like population. This differentiation is controlled by type 1 cytokines and is associated with a glycolytic program involving the transcription factor HIF1. Collectively, our data reveal how tissue-resident ILCs adapt to type 1 inflammation toward a pathogen tailored immune response.

immunology↗

bioRxiv2020

Mycobacteria-host interactions in human bronchiolar airway organoids

Tuberculosis, one of the oldest human pathogens remains a major global health threat. Recent advances in organoid technology offer a unique opportunity to grow different human "organs" in vitro, including the human airway, that faithfully recapitulate tissue architecture and function. We have explored the potential of human airway organoids (AOs) as a novel system in which to model tuberculosis infection. To this end, we adapted biosafety containment level 3-approved procedures to allow successful microinjection of Mycobacterium tuberculosis, the causative agent of tuberculosis, into AOs. We reveal that mycobacteria infected epithelial cells with low efficiency, and that the organoid microenvironment was able to control, but not eliminate the pathogen. We demonstrate that AOs responded to infection by inducing cytokine and antimicrobial peptide production, and inhibiting mucins. Given the importance of myeloid cells in tuberculosis infection, we co-cultured mycobacteria-infected organoids with human monocyte-derived macrophages, and found that these cells were recruited to the organoid epithelium. We conclude that adult stem cell-derived airway organoids can be used to model early events of tuberculosis infection and offer new avenues for fundamental and therapeutic research.

systems biology↗

bioRxiv2020

Host-derived lipids from tuberculous pleurisy impair macrophage microbicidal-associated metabolic activity

Mycobacterium tuberculosis (Mtb) regulates the macrophage metabolic state to thrive in the host. Yet, the responsible mechanisms remain elusive. Macrophage activation towards the microbicidal (M1) program depends on the HIF-1 -mediated metabolic shift from oxidative phosphorylation towards glycolysis. Here, we asked whether a tuberculosis (TB) microenvironment changes the M1 macrophage metabolic state. We exposed M1 macrophages to the acellular fraction of tuberculous pleural effusions (TB-PE), and found lower glycolytic activity, accompanied by elevated levels of oxidative phosphorylation and bacillary load, compared to controls. The host-derived lipid fraction of TB-PE drove these metabolic alterations. HIF-1 stabilization reverted the effect of TB-PE by restoring M1 metabolism. As a proof-of-concept, Mtb-infected mice with stabilized HIF-1 displayed lower bacillary loads and a pronounced M1-like metabolic profile in alveolar macrophages. Collectively, we demonstrate that host-derived lipids from a TB-associated microenvironment alter the M1 macrophage metabolic reprogramming by hampering HIF-1 functions, thereby impairing control of Mtb infection.

immunology↗

bioRxiv2020

Colon-specific immune microenvironment regulates cancer progression versus rejection

BackgroundImmunotherapies have achieved clinical benefit in many types of cancer but remain limited to a subset of patients in colorectal cancer (CRC). Resistance to immunotherapy can be attributed in part to tissue-specific factors constraining antitumor immunity. Thus, a better understanding of how the colon microenvironment shapes the immune response to CRC is needed to identify mechanisms of resistance to immunotherapies and guide the development of novel therapeutics. MethodsIn an orthotopic mouse model of MC38-CRC, tumor progression was monitored by bioluminescence imaging and the immune signatures were assessed at a transcriptional level using NanoString and at a cellular level by flow cytometry. ResultsDespite initial tumor growth in all mice, only 25 to 35% of mice developed a progressive lethal CRC while the remaining animals spontaneously rejected their solid tumor. No tumor rejection was observed in the absence of adaptive immunity, nor when MC38 cells were injected in non-orthotopic locations, subcutaneously or into the liver. We observed that progressive CRC tumors exhibited a protumor immune response, characterized by a regulatory T-lymphocyte pattern, discernible shortly post-tumor implantation, as well as suppressive myeloid cells. In contrast, tumor-rejecting mice presented an early inflammatory response and an antitumor microenvironment enriched in CD8+ T cells. ConclusionsTaken together, our data demonstrate the role of the colon microenvironment in regulating the balance between anti or protumor immune responses. While emphasizing the relevance of the CRC orthotopic model, they set the basis for exploring the impact of the identified signatures in colon cancer response to immunotherapy.

cancer biology↗

bioRxiv2019

Mycobacterium tuberculosis Modulates the Metabolism of Alternatively Activated Macrophages to Promote Foam Cell Formation and Intracellular Survival

The ability of Mycobacterium tuberculosis (Mtb) to persist inside host cells relies on metabolic adaptation, like the accumulation of lipid bodies (LBs) in the so-called foamy macrophages (FM). Indeed, FM are favorable to Mtb. The activation state of macrophages is tightly associated to different metabolic pathways, such as lipid metabolism, but whether differentiation towards FM differs between the macrophage activation profiles remains unclear. Here, we aimed to elucidate if distinct macrophage activation states exposed to a tuberculosis-associated microenvironment can accumulate LBs, and its impact on the control of infection. We showed that signal transducer and activator of transcription 6 (STAT6) activation in interleukin (IL)-4-activated human macrophages (M(IL-4)) prevents FM formation induced by pleural effusion from patients with tuberculosis. In these cells, LBs are disrupted by lipolysis, and the released fatty acids enter the {beta}-oxidation (FAO) pathway fueling the generation of ATP in mitochondria. We demonstrated that inhibition of the lipolytic activity or of the FAO drives M(IL-4) macrophages into FM. Also, exhibiting a predominant FAO metabolism, mouse alveolar macrophages are less prone to become FM compared to bone marrow derived-macrophages. Upon Mtb infection, M(IL-4) macrophages are metabolically re-programmed towards the aerobic glycolytic pathway and evolve towards a foamy phenotype, which could be prevented by FAO activation or inhibition of the hypoxia-inducible factor 1-alpha (HIF-1)-induced glycolytic pathway. In conclusion, our results demonstrate a role for STAT6-driven FAO in preventing FM differentiation, and reveal an extraordinary capacity by Mtb to rewire metabolic pathways in human macrophages and induce the favorable FM. IMPORTANCETuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb). While its treatment was already standardized, TB remains one of the top 10 death causes worldwide. A major problem is the efficient adaptation of Mtb to the macrophage intracellular milieu, which includes deregulation of the lipid metabolism leading to the formation of foamy macrophages (FM) which are favorable to Mtb. A critical aspect of our work is the use of tuberculous pleural effusions (TB-PE) -- human-derived biological fluid capable of mimicking the complex microenvironment of the lung cavity upon Mtb infection -- to study the FM metabolic modulation. We revealed how the STAT6 transcription factor prevents FM formation induced by PE-TB, and how Mtb counteracts it by activating another transcription factor, HIF-1, to re-establish FM. This study provides key insights in host lipid metabolism, macrophage biology and pathogen subversion strategies, to be exploited for prevention and therapeutic purposes in infectious diseases.

immunology↗