Spatial multiomic profiling reveals the novel polarization of foamy macrophages within necrotic granulomatous lesions developed in lungs of C3HeB/FeJ mice infected with Mycobacterium tuberculosis

Lung-resident memory Th2 cells regulate pulmonary cryptococcosis by inducing type-II granuloma formation

Lung-resident memory T cells (lung TRMs) settle in the lung and respond rapidly to external antigens, and are therefore considered to have great potential for development of respiratory vaccines. Here, we demonstrate that lung-resident memory Th2 cells (lung TRM2) protect against pulmonary mycosis caused by Cryptococcus gattii. We developed novel whole-cell intranasal vaccines using a heat-inactivated C.gattii capsule-deficient strain cap59Δ, which induced ST-2+ Gata-3+ lung TRM2 specifically responding to C.gattii whole-cell antigen. Lung fungal burden and survival rate were significantly improved in immunized mice after infection challenge. The immunosuppressive agent FTY720 did not impact vaccine effectiveness, and adoptive transfer of lung TRMs into Rag-1-deficient mice decreased the lung fungal burden. In IL-4/IL-13 double-knockout (DKO) mice, immunization did not efficiently induce eosinophil recruitment and granuloma formation, and the fungal burden was not decreased after infection challenge. Co-culture of lung TRM2 with myeloid lineages induced multinucleated giant cells (MGCs) in the presence of antigen, which phagocytosed live C.gattii cells without opsonization, whereas lung TRM2 from DKO mice did not induce MGCs. These findings provide a new model in which lung TRM2 suppress C.gattii infection via granuloma induction.

Building Spatiotemporal Understanding of Mycobacterium tuberculosis-Host Interactions

Heterogeneity during Mycobacterium tuberculosis (Mtb) infection greatly impacts disease outcome and complicates treatment. This heterogeneity encompasses many facets, spanning local differences in the host immune response to Mtb and the environment experienced by the bacterium, to nonuniformity in Mtb replication state. All of these facets are interlinked and each can affect Mtb susceptibility to antibiotic treatment. In-depth spatiotemporal understanding of Mtb-host interactions is thus critical to both fundamental comprehension of Mtb infection biology and for the development of effective therapeutic regimens. Such spatiotemporal understanding dictates the need for analysis at the single bacterium/cell level in the context of intact tissue architecture, which has been a significant technical challenge. Excitingly, innovations in spatial single cell methodology have opened the door to such studies, beginning to illuminate aspects ranging from intergranuloma differences in cellular composition and phenotype, to sublocation differences in Mtb physiology and replication state. In this perspective, we discuss recent studies that demonstrate the potential of these methodological advancements to reveal critical spatiotemporal insight into Mtb-host interactions, and highlight future avenues of research made possible by these advances.

Transcriptional regulators SP110 and SP140 modulate inflammatory response genes in Mycobacterium tuberculosis-infected human macrophages

Understanding the functions of human transcriptional regulatory genes SP110 and SP140 during Mycobacterium tuberculosis infection is crucial; in a mouse model, homologous genes Sp110 and Sp140 have been shown to negatively regulate inflammatory response genes, including the type I interferon (IFN) response. The reduction of these genes in mice is associated with susceptibility to M. tuberculosis infection and the development of necrotizing granulomatous lesions. To investigate the involvement of SP110 and SP140 in human inflammatory response, we analyzed their regulatory manner in THP-1 macrophages infected with M. tuberculosis. Genome-wide transcriptional profiling revealed that the depletion of SP110 and/or SP140 impaired the induction of gene expression associated with inflammatory responses, including IFN response genes, although it had little effect on the intracellular proliferation of M. tuberculosis. By contrast, genes related to phosphorylation were upregulated in infected macrophages with SP110 and/or SP140 knockdown, but downregulated in infected control macrophages without their knockdown. Reverse transcription-quantitative PCR and ELISA further confirmed the impairment of the induction of IFN response genes by the depletion of SP110 and/or SP140 in M. tuberculosis-infected macrophages. These findings suggest that human SP110 and SP140 act as positive regulators for genes associated with inflammatory responses in M. tuberculosis-infected macrophages.

IMPORTANCE

Tuberculosis (TB) is one of the most serious infectious diseases, with high morbidity and mortality worldwide. C3HeB/FeJ mice are widely utilized for evaluating anti-TB drugs because their drug sensitivity and pathology during M. tuberculosis infection resemble those of human TB, including the development of necrotizing granulomas. Downregulation of the transcriptional regulatory genes Sp110 and Sp140 in C3HeB/FeJ mice has been demonstrated to activate gene expression associated with inflammatory responses during M. tuberculosis infection, resulting in susceptibility to the infection. Here, we examined the regulatory manner of SP110 and SP140 using transcriptomic analysis in M. tuberculosis-infected human macrophages. Depletion of SP110 and/or SP140 in M. tuberculosis-infected THP-1 macrophages impaired the induction of gene expression associated with inflammatory responses, including interferon response genes, compared with that in control macrophages. These results suggest that human SP110 and SP140 act as positive regulators for genes associated with inflammatory responses upon M. tuberculosis infection.

The efflux pumps Rv1877 and Rv0191 play differential roles in the protection of Mycobacterium tuberculosis against chemical stress

Background

It was previously shown that GlnA3sc enabled Streptomyces coelicolor to survive in excess polyamines. However, subsequent studies revealed that Rv1878, the corresponding Mycobacterium tuberculosis (M.tb) ortholog, was not essential for the detoxification of spermine (Spm), in M.tb. On the other hand, the multi-drug efflux pump Rv1877 was previously shown to enable export of a wide range of compounds, while Rv0191 was shown to be more specific to chloramphenicol.

Rationale

Therefore, we first wanted to determine if detoxification of Spm by efflux can be achieved by any efflux pump, or if that was dependent upon the function of the pump. Next, since Rv1878 was found not to be essential for the detoxification of Spm, we sought to follow-up on the investigation of the physiological role of Rv1878 along with Rv1877 and Rv0191.

Approach

To evaluate the specificity of efflux pumps in the mycobacterial tolerance to Spm, we generated unmarked ∆rv1877 and ∆rv0191 M.tb mutants and evaluated their susceptibility to Spm. To follow up on the investigation of any other physiological roles they may have, we characterized them along with the ∆rv1878 M.tb mutant.

Results

The ∆rv1877 mutant was sensitive to Spm stress, while the ∆rv0191 mutant was not. On the other hand, the ∆rv1878 mutant grew better than the wild-type during iron starvation yet was sensitive to cell wall stress. The proteins Rv1877 and Rv1878 seemed to play physiological roles during hypoxia and acidic stress. Lastly, the ∆rv0191 mutant was the only mutant that was sensitive to oxidative stress.

Conclusion

The multidrug MFS-type efflux pump Rv1877 is required for Spm detoxification, as opposed to Rv0191 which seems to play a more specific role. Moreover, Rv1878 seems to play a role in the regulation of iron homeostasis and the reconstitution of the cell wall of M.tb. On the other hand, the sensitivity of the ∆rv0191 mutant to oxidative stress, suggests that Rv0191 may be responsible for the transport of low molecular weight thiols.

Differential diagnosis of cervical lymphadenopathy: Integration of postvascular phase of contrast-enhanced ultrasound and predictive nomogram model

BACKGROUND

Distinguishing benign from malignant cervical lymph nodes is critical yet challenging. This study evaluates the postvascular phase of contrast-enhanced ultrasound (CEUS) and develops a user-friendly nomogram integrating demographic, conventional ultrasound, and CEUS features for accurate differentiation.

METHODS

We retrospectively analyzed 395 cervical lymph nodes from 395 patients between January 2020 and December 2022. The cohort was divided into training and validation sets using stratified random sampling. A predictive model, based on demographic, ultrasound, and CEUS features, was created and internally validated.

RESULTS

The training set included 280 patients (130 benign, 150 malignant nodes) and the validation set 115 patients (46 benign, 69 malignant). Relative hypoenhancement in the postvascular phase emerged as a promising indicator for MLN, with sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 96.7 %,52.3 %, 70.0 %, 93.2 %, and 76.1 %, respectively in the training set and 95.7 %, 52.2 %, 75.0 %, 88.9 %, and 74.8 % in the validation set. Age over 50 years, history of malignancy, short-axis diameter greater than 1.00 cm, focal hyperechogenicity, ill-defined borders, and centripetal perfusion were also identified as independent MLN indicators. The nomogram prediction model showed outstanding accuracy, with an area under the curve (AUC) of 0.922 (95 % CI: 0.892-0.953) in the training set and 0.914 (95 % CI: 0.864-0.963) in the validation set.

CONCLUSION

Relative hypoenhancement in the postvascular phase of CEUS, combined with demographics and ultrasound features, is effective for identifying MLNs. The developed prediction model, with a user-friendly nomogram, can facilitate clinical decision-making.