Tuberculosis remains a global health challenge due to drug-resistant strains. MmpL3 inhibitors have emerged as promising anti-tubercular agents, and their clinical development has been hindered by poor microsomal stability. This study computationally designed and screened 40 spirocyclic analogs, and compared them with ICA38 and SQ109. In silico analyses, including docking, MD simulations, and DFT calculations, were conducted to assess their potential as anti-tubercular agents, highlighting promising candidates for further development. Docking studies using Glide software identified C21 (3,4- dichloro derivative) and C20 (5-chloro derivative) as promising candidates, exhibiting binding scores of -9.79 kcal/mol and -9.64 kcal/mol, respectively. Both compounds interacted with the active site residue Asp645 via hydrogen bonding and also formed a hydrophobic interaction. DFT results revealed that C21 displayed the balanced chemical reactivity, characterized by high dipole moment (3.63D), an optimal energy gap (0.18752 eV), softness and hardness (η = 0.09376 eV, σ = 10.666 eV⁻¹), high electron affinity (0.02305 eV), high electronegativity (0.11681 eV) and high ionization potential (0.21057 cV). On the other hand, C20 exhibited similar electronic properties with marginal differences than C21. MD simulations showed C21 and C20's stability (RMSD 2.4 Å and 2.2 Å, RMSF <2.5 Å), indicating improved Arg344-Leu354 stability. Additionally, C21 and C20 maintained Asp645 interactions (91 %, 97 %) and showed strong binding with free energy values (MMGBSA: -72.23, -66.50 kcal/mol). These findings highlight the efficiency of the compounds C21 and C20 with strong binding affinity, favorable stability, and optimal electronic properties, making them promising candidates for further development of next-generation MmpL3 inhibitors.

Tuberculosis (TB) remains a critical health threat, particularly with the emergence of multidrug-resistant strains. This demands attention from scientific communities and healthcare professionals worldwide to develop effective treatments. The enhanced intracellular survival (Eis) protein is an acetyltransferase enzyme of Mycobacterium tuberculosis that functions by adding acetyl groups to aminoglycoside antibiotics, which interferes with their ability to bind to the bacterial ribosome, thereby preventing them from inhibiting protein synthesis and killing the bacterium. Therefore, targeting this protein accelerates the chance of restoring the aminoglycoside drug activity, thereby reducing the emergence of drug-resistant TB. For this, we have screened 406,747 natural compounds from the Coconut database against Eis protein. Based on MM/GBSA rescoring binding energy, the top 5 most prominent natural compounds, viz. CNP0187003 (- 96.14 kcal/mol), CNP0176690 (- 93.79 kcal/mol), CNP0136537 (- 92.31 kcal/mol), CNP0398701 (- 91.96 kcal/mol), and CNP0043390 (- 91.60 kcal/mol) were selected. These compounds exhibited the presence of a substantial number of hydrogen bonds and other significant interactions confirming their strong binding affinity with the Eis protein during the docking process. Subsequently, the MD simulation of these compounds exhibited that the Eis-CNP0043390 complex was the most stable, followed by Eis-CNP0187003 and Eis-CNP0176690 complex, further verified by binding free energy calculation, principal component analysis (PCA), and Free energy landscape analysis. These compounds demonstrated the most favourable results in all parameters utilised for this investigation and may have the potential to inhibit the Eis protein. There these findings will leverage computational techniques to identify and develop a natural compound inhibitor as an alternative for drug-resistant TB.

Autophagy is a widespread physiological process in the body, which also protects the host by degrading invading pathogens and harmful substances during pathological conditions. Nevertheless, Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis, has evolved strategies to subvert autophagy by modulating microRNA (miRNA) expression, enabling its escape from host defenses. In this study, we established an in vitro model using the human macrophage cell line infected with the highly virulent MTB strain H37Rv. Through RNA sequencing and bioinformatic analysis post H37Rv infection, we screened 14 differentially expressed miRNAs. We predicted and demonstrated that miR-30c-1-3p inhibits autophagy and promotes MTB survival by targeting ATG4B and ATG9B during the infection process. The results showed that miR-30c-1-3p expression was gradually increased before 12 h of H37Rv infection, followed by a decrease. Overexpression of miR-30c-1-3p suppressed autophagic activity. We also identified the targeting of miR-30c-1-3p to ATG4B and ATG9B for the first time, and overexpression of both ATG4B and ATG9B, alone or together, on the basis with upregulation of miR-30c-1-3p reversed the inhibition of autophagy. Autophagy levels were analyzed at different levels by western blot, immunofluorescence, and transmission electron microscopy, all of which showed that upregulation of miR-30c-1-3p inhibited autophagy during H37Rv infection. Additionally, the intervention of miR-30c-1-3p mimics resulted in an increased bacterial load in macrophages, suggesting that MTB achieves immune evasion by upregulating miR-30c-1-3p during infection. In conclusion, our study provides a valuable target for the development of host-directed anti-tuberculosis therapy as well as a new diagnostic marker.

Mycobacterium bovis causes bovine tuberculosis (bTB), an infectious disease of cattle that represents a zoonotic threat to humans. Research has shown that the peripheral blood (PB) transcriptome is perturbed during bTB disease but the genomic architecture underpinning this transcriptional response remains poorly understood. Here, we analyse PB transcriptomics data from 63 control and 60 confirmed M. bovis-infected animals and detect 2592 differently expressed genes perturbing multiple immune response pathways. Leveraging imputed genome-wide SNP data, we characterise thousands of cis-expression quantitative trait loci (eQTLs) and show that the PB transcriptome is substantially impacted by intrapopulation genomic variation during M. bovis infection. Integrating our cis-eQTL data with bTB susceptibility GWAS summary statistics, we perform a transcriptome-wide association study and identify 115 functionally relevant genes (including RGS10, GBP4, TREML2, and RELT) and provide important new omics data for understanding the host response to mycobacterial infections that cause tuberculosis in mammals.

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), remains one of the leading causes of death among infectious diseases. Enhancing the ability of anti-tuberculosis drugs to eradicate Mycobacterium tuberculosis within host cells remains a significant challenge.

A mannosamine-modified nanoparticle delivery system was developed using poly(lactic-co-glycolic acid) (PLGA) copolymers to enhance the targeted delivery of rifapentine (RPT) to macrophages. D-mannosamine was conjugated to PLGA-polyethylene glycol (PLGA-PEG) copolymers through EDC/NHS coupling chemistry, and the resultant RPT-MAN-PLGA-PEG nanoparticles (NPs) were prepared through a combination of phacoemulsification and solvent evaporation methods. The physicochemical properties, toxicity, in vitro drug release profiles, stability, cellular uptake, and anti-TB efficacy of the NPs were systematically evaluated.

The RPT-MAN-PLGA-PEG NPs had a mean particle size of 108.2 ± 7.2 nm, with encapsulation efficiency and drug loading rates of 81.2 ± 6.3% and 13.7 ± 0.7%, respectively. RPT release from the NPs was sustained for over 60 hours. Notably, the phagocytic uptake of the MAN-PLGA NPs by macrophages was significantly higher compared to PLGA-PEG NPs. Both NPs improved pharmacokinetic parameters without inducing significant organ toxicity. The minimum inhibitory concentration for the NPs was 0.047 μg/mL, compared to 0.2 μg/mL for free RPT.

The engineered RPT-MAN-PLGA-PEG NPs effectively enhanced macrophage uptake in vitro and facilitated the intracellular clearance of Mtb. This nanoparticle-based delivery system offers a promising approach for improving the precision of anti-TB therapy, extending drug release, optimizing pharmacokinetic profiles, augmenting antimicrobial efficacy, and mitigating drug-related toxicities.

The comorbid course of chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis is an important medical and social problem. Both diseases, although having different etiologies, have many overlapping relationships that mutually influence their course and prognosis. The aim of the current review is to discuss the role of different immune mechanisms underlying inflammation in COPD and pulmonary tuberculosis. These mechanisms are known to involve both the innate and adaptive immune system, including various cellular and intercellular interactions. There is growing evidence that immune mechanisms involved in the pathogenesis of both COPD and tuberculosis may jointly contribute to the tuberculosis-associated obstructive pulmonary disease (TOPD) phenotype. Several studies have reported prior tuberculosis as a risk factor for COPD. Therefore, the study of the mechanisms that link COPD and tuberculosis is of considerable clinical interest.

Primary and post-primary TB are distinct entities. Primary TB occurs when the patient is infected with Mycobacterium tuberculosis (MTB) for the first time without prior immunity, and post-primary TB occurs when the patient has developed immunity against the primary infection. Post-primary TB occurs only in humans. It accounts for 80% of all clinical cases and nearly 100% of transmissions of infection. Early lesions of post-primary TB are reversible, and studying it using modern immunological tools holds the key to developing preventive or treatment strategies. Human lung tissue from untreated TB patients was acquired from pathology archives stored at the Gades Institute of Pathology, Haukeland University Hospital, Bergen, Norway, from 1931 to 1947. Manual immunohistochemistry was performed for macrophage (CD68, CD64 and CD163), T cells (CD3 and CD8), matrix metalloproteinases (MMP-9), and markers for programmed death-pathway PD/PDL-1. Digital quantification was performed using Qupath software. In early lesions of post-primary TB, macrophages showed mixed-phenotype M1 and M2, expressed PDL-1, and were compartmentalized in the alveolar space. T-cells expressed PD-1 and were compartmentalized in the interstitial wall surrounding early lesions. MTB antigens and MMP-9 were also found in early lesions. As the lesion progressed towards necrosis, macrophages showed predominant M1 morphology, and expressions of PDL-1, PD-1, CD8+ cells, and MTB antigens increased. In the early lesions of post-primary TB, the compartmentalization of macrophages in the alveoli and T cells in the interstitium was shown. The PDL-PD1 pathway probably facilitated the mycobacterial growth by evading host immunity.

Mycobacterium tuberculosis (Mtb) is a crucial and destructive intracellular pathogen responsible for causing tuberculosis (TB), a disease of substantial morbidity and mortality. Mtb capsular polysaccharides can misdirect the host's immune response pathways, resulting in additional challenges in TB treatment. These capsule polysaccharides are biosynthesized by a series of stealth proteins including CpsY. Our prior investigations elucidated the structural and functional information of the central domain (aa 201-520) of CpsY within Mtb. However, within the host milieu, it is the full-length iteration of CpsY, rather than its truncated form CpsY201-520, that assumes pivotal roles in immune evasion. Consequently, investigating the functional mechanism of full-length CpsY is extremely important. Here, we found that the indispensable role of four conserved regions (CR1-CR4) in governing the phosphotransferase activity of full-length CpsY. Notably, the deletion of S2 (ΔS2) dramatically increased the activity compared to the wild-type (WT) full-length CpsY, thereby revealing S2 in the regulatory dynamics governing the inactivation and activation of full-length CpsY. The gene cpsY helps Mtb to survive in macrophages. Our findings were useful for the development of vaccines and immunotherapies targeting Mtb.

In vitro models serve as valuable tools for understanding the complex cellular and molecular interactions involved in granuloma formation, providing a controlled environment to explore the underlying mechanisms of their development and function. Various models have been developed to replicate granulomatous diseases, even though they may lack the sophistication needed to fully capture the variability present in clinical spectra and environmental influences. Traditional cultures of PBMCs have been widely used to generate granuloma models, enabling the study of aggregation responses to various stimuli. However, growing cells on a two-dimensional (2D) plastic surface as a monolayer can lead to altered cellular responses and the modulation of signaling pathways, which may not accurately represent in vivo conditions. In response to these limitations, the past decade has seen significant advancements in the development of three-dimensional (3D) in vitro models, which more effectively mimic in vivo conditions and provide better insights into cell-cell and cell-microenvironment interactions. Meanwhile, the use of in vivo animal models in biomedical research must adhere to the principle of the three Rs (replacement, reduction, and refinement) while ensuring that the models faithfully replicate human-specific processes. This review summarizes and compares the main models developed to investigate granulomas, focusing on their contribution to advancing our understanding of granuloma biology. We also discuss the strengths and limitations of each model, offering insights into their biological relevance and practical applications.

In tuberculosis (TB) infection, monocytes play a crucial role in regulating the balance between immune tolerance and immune response through various mechanisms. A deeper understanding of the roles of monocyte subsets in TB immune responses may facilitate the development of novel immunotherapeutic strategies and improve TB prevention and treatment.

We retrieved and processed raw single-cell RNA-seq data from SRP247583. Single-cell RNA-seq combined with bioinformatics analysis was employed to investigate the roles of monocytes in TB progression.

Our findings revealed that classical monocytes expressing inflammatory mediators increased as the disease progressed, whereas non-classical monocytes expressing molecules associated with anti-pathogen infection were progressively depleted. Pseudotime analysis delineated the differentiation trajectory of monocytes from classical to intermediate to non-classical subsets. An abnormal differentiation trajectory to non-classical monocytes may represent a key mechanism underlying TB pathogenesis, with CEBPB and CORO1A identified as genes potentially related to TB development. Analysis of key transcription factors in non-classical monocytes indicated that IRF9 was the only downregulated transcription factor with high AUC activity in this subset. The expression of IRF9 exhibited a decreasing trend in both latent TB infection (LTBI) and active TB groups. Furthermore, dysregulation of transcription factor regulatory networks appeared to impair ferroptosis, with ferroptosis-associated genes MEF2C, MICU1, and PRR5 identified as potential targets of IRF9. Through cell communication analysis, we found that interactions between non-classical monocytes and other subpopulations may mediate TB progression, with MIF and LGALS9 highlighted as potential signaling pathways.

This study employs bioinformatics analysis in conjunction with single-cell sequencing technology to uncover the crucial role of monocyte subsets in tuberculosis infection.

Circular RNAs (circRNAs) are covalently closed non-coding RNAs formed by back-splicing, lacking a 5' cap and poly-A tail. They could act as important regulatory factors in the host's anti-tuberculosis immune process, but only a few have been identified, and their molecular mechanisms remain largely unclear. Here, we identified a novel circRNA, circ-ZNF277, which responds to Mycobacterium tuberculosis (Mtb) infection in THP-1 cells. Circ-ZNF277 binds microRNA-378d (miR-378d) in vivo. The expression level of circ-ZNF277 affects the clearance of the intracellular Mtb in THP-1 cells. Mechanistically, more circ-ZNF277 molecules could absorb more miR-378d, thereby competitively activating the NF-κB signaling pathway, promoting the release of pro-inflammatory cytokines including interleukins IL-1β and IL-6, and tumor necrosis factor-α (TNF-α), and inhibiting the survival of intracellular Mtb. Expressing miR-378d or si-Rab10 targeting the transcription of Rab10 could antagonize the effects of overexpression of circ-ZNF277, resulting in the reduced intracellular survival of Mtb. In summary, circ-ZNF277 inhibits the intracellular survival of Mtb via the miR-378d/Rab10 axis. This finding represents a novel mechanism of circular RNA in regulating host immune responses during Mtb infection.

Mycobacteria have several mechanisms for evasion of protective responses mounted by the host. In this study, we unravel yet another mechanism that is mediated by Toll-Like Receptors TLR2, TLR4, and TLR7 in epithelial cells. We show that mycobacterial infection of epithelial cells increases the expression of TLR2, TLR4, and TLR7. Stimulation of either TLR along with mycobacterial infection results in an inhibition of oxidative burst resulting in increased survival of mycobacteria inside epithelial cells. TLR stimulation along with mycobacterial infection also inhibits activation of epithelial cells for T cell responses by differentially regulating the activation of ERK-MAPK and p38-MAPK along with inhibition of co-stimulatory molecule CD86 expression. Furthermore, stimulation of either TLR inhibits the induction of apoptosis and autophagy. Knockdown of either TLR by specific siRNAs reverses the inhibition by ROS and apoptosis by mycobacteria and results in reduced intracellular survival of mycobacteria in a MyD88-dependent manner. These results point towards a negative role for TLR2, TLR4, and TLR7 in regulating protective responses to M. bovis BCG infection in epithelial cells.

The global escalation in tuberculosis (TB) cases accompanied by the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (M.tb) emphasizes the critical requirement for novel potent drugs. The M.tb demonstrates extraordinary adaptability, thriving in diverse conditions, and always finds itself in win-win situations regardless of whether the environment is favorable or unfavorable; no matter the magnitude of the challenge, it can endure and survive. This review aims to uncover the role of multiple stress sensors of M.tb that assist bacteria in remaining viable within the host for years against various physiological stresses offered by the host. M.tb is an exceptionally triumphant pathogen, primarily due to its adeptness in developing defense mechanisms against stressful situations. The recent advances emphasize the significance of M.tb stress sensors, including chaperones, proteases, transcription factors, riboswitches, inteins, etc., employed in responding to a spectrum of physiological stresses imposed by the host, encompassing surface stress, host immune responses, osmotic stress, oxidative and nitrosative stresses, cell envelope stress, environmental stress, reductive stress, and drug pressure. These sensors act as silent defenders orchestrating adaptive strategies, with limited comprehensive information in current literature, necessitating a focused review. The M.tb strategies utilizing these stress sensors to mitigate the impact of traumatic conditions demand attention to neutralize this pathogen effectively. Moreover, the intricacies of these stress sensors provide potential targets to design an effective TB drug using structure-based drug design against this formidable global health threat.

Extrapulmonary tuberculosis (EPTB) accounts for approximately 17% of all Mycobacterium tuberculosis (M.tb) infections globally. Immunocompromised individuals, such as those with HIV infection or type 2 diabetes mellitus (T2DM), are at an increased risk for EPTB. Previous studies have demonstrated that patients with HIV and T2DM exhibit diminished synthesis of glutathione (GSH) synthesizing enzymes. In a murine model, we showed that the diethyl maleate (DEM)-induced depletion of GSH in the lungs led to increased M.tb burden and an impaired pulmonary granulomatous response to M.tb infection. However, the effects of GSH depletion during active EPTB in the liver and spleen have yet to be elucidated. In this study, we evaluated hepatic GSH and malondialdehyde (MDA) levels, as well as cytokine profiles, in untreated and DEM-treated M.tb-infected wild-type (WT) C57BL/6 mice. Additionally, we assessed hepatic and splenic M.tb burdens and tissue pathologies. DEM treatment resulted in a significant decrease in the levels of the reduced form of GSH and an increase in MDA, oxidized GSH, and interleukin (IL)-6 levels. Furthermore, DEM-induced GSH decrease was associated with decreased production of IL-12 and IL-17 and elevated production of interferon-gamma (IFN-γ), tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β. A significant increase in M.tb growth was detected in the liver and spleen in DEM-treated M.tb-infected mice. Large, disorganized lymphocyte infiltrates were detected in the hepatic tissues of DEM-treated mice. Overall, GSH diminishment impaired the granulomatous response to M.tb in the liver and exacerbated M.tb growth in both the liver and spleen. These findings provide critical insights into the immunomodulatory role of GSH in TB pathogenesis and suggest potential therapeutic avenues for the treatment of extrapulmonary M.tb infections.

Tuberculosis (TB) is a chronic wasting infectious disease caused by Mycobacterium tuberculosis (MTB) or Mycobacterium bovis that can be transmitted among people and domestic animals. During the development of TB, macrophages of the innate immune system can act against MTB via autophagy and apoptosis to prevent the spread of the disease. Among the many autophagy regulatory pathways, the adenosine monophosphate (AMP)-activated protein kinase (AMPK)-mammalian rapamycin target protein (mTOR)-Unc-51-like kinase 1 (ULK1) pathway has received considerable attention. This study investigates the regulatory role of the AMPK-mTOR-ULK1 pathway in attenuating M. bovis Bacillus Calmette-Guérin (BCG)-induced autophagy and apoptosis in murine monocyte macrophages (RAW264.7). Changes in macrophage autophagy and apoptosis were analyzed using the AMPK activator AICAR and inhibitor Compound C to interfere with the AMPK-mTOR-ULK1 pathway and siRNA to silence the pathway. Consequently, BCG stimulation of macrophages significantly activated the AMPK-mTOR-ULK1 pathway while BCG-induced macrophage AMPK activation promoted macrophage autophagy and apoptosis. Activation of the AMPK-mTOR-ULK1 pathway by AICAR significantly improved autophagy occurrence in BCG-induced macrophages and increased apoptosis while Compound C with siRNA produced opposing effects by attenuating autophagy and apoptosis in BCG-induced macrophages. Thus, the AMPK-mTOR-ULK1 pathway has a dual regulatory role in BCG-induced macrophage autophagy and apoptosis and may have synergistic effects. This study analyzes the mechanism of resistance of host cells to MTB and provides a theoretical basis for new therapeutic strategies and related drug development.

Edwardsiella piscicida-induced lethal enteritis is a major threat to the sustainable development of seahorse aquaculture. The roles of Carbohydrate-Active enzymes (CAZymes) in interactions between the pathogen and the host are poorly understood. In this study, we found that 22 key CAZymes encoded by E. piscicida might involve in the coordination of five key stages of infection. Specifically, during the motility, adherence, and invasion stages, 10 CAZymes, including CE4, PL8, and CBM48, may significantly increase the activities of Lipid metabolism-associated pathways of the intestinal microbiota (P < 0.01), facilitating pathogen invasion of the host intestinal epithelium. During the replication stage, 11 CAZymes, including GH20, GT4, and GH3, may significantly increase activities of pathways associated with Carbohydrate metabolism (P < 0.01) to promote replication and proliferation of the pathogen. And for avoiding host defenses, GH2 and GH1 may enhance activities of both Carbohydrate and Amino acid metabolic pathways (P < 0.01), facilitating infection and immune evasion. Conjoint analysis showed that E. piscicida might mainly rely on Carbohydrate metabolism for infection, while the host might activate Amino acid metabolic pathways for self-defense. In addition, expressions of 10 key genes, Aldh9a1b, Aoc1, Tpi1b, PCK1, Ldha, Me1, Gla, Cel.2, Ugdh, and Mao, were significantly altered (P < 0.01) and may be used for characterizing host responses to E. piscicida infection. Activities of both Glycolysis/Gluconeogenesis and Tryptophan metabolism were found oppositely changed (P < 0.01) between pathogen and host, respectively, representing the primary focuses of the competition. Overall, this study provides new insights into E. piscicida-mediated intestinal enteritis in fish for the first time from the perspective of CAZymes, as well as a theoretical reference for the prevention and control of these diseases in the aquaculture of seahorses and other fish.

Mycobacterium tuberculosis (Mtb) complex, responsible for tuberculosis (TB) infection, continues to be a predominant global cause of mortality due to intricate host-pathogen interactions that affect disease progression. MicroRNAs (miRNAs), essential posttranscriptional regulators, have become pivotal modulators of these relationships. Recent findings indicate that miRNAs actively regulate immunological responses to Mtb complex by modulating autophagy, apoptosis, and immune cell activities. This has resulted in increased interest in miRNAs as prospective diagnostic indicators for TB, especially in differentiating active infection from latent or inactive stages. Variations in miRNA expression during Mtb infection indicate disease progression and offer insights into the immune response. Furthermore, miRNAs present potential as therapeutic targets in host-directed therapy (HDT) techniques for TB infection. This work examines the function of miRNAs in TB pathogenesis, with the objective of identifying particular miRNAs that regulate the immune response to the Mtb complex, evaluating their diagnostic value and exploring their therapeutic implications in host-directed therapy for TB infection. The objective is to enhance comprehension of how miRNAs can facilitate improved diagnosis and treatment of TB.

Copper is a vital trace element crucial for mediating interactions between Mycobacterium and macrophages. Within these immune cells, copper modulates oxidative stress responses and signaling pathways, enhancing macrophage immune functions and facilitating Mycobacterium clearance. Conversely, copper may promote Mycobacterium escape from macrophages through various mechanisms: inhibiting macrophage activity, diminishing phagocytic and bactericidal capacities, and supporting Mycobacterium survival and proliferation. This paradox has intensified research focus on the regulatory role of copper in immune cell-pathogen interactions. Interactions among metal ions can affect Mycobacterium concentration, distribution, and activity within an organism. In this review, we have elucidated the role of copper in these interactions, focusing on the mechanisms by which this metal influences both the immune defense mechanisms of macrophages and the survival strategies of Mycobacterium. The findings suggest that manipulating copper levels could enhance macrophage bactericidal functions and potentially limit Mycobacterium resistance. Therefore, elucidating the regulatory role of copper is pivotal for advancing our understanding of metal homeostasis in immune cell-pathogen dynamics and TB pathogenesis. Furthermore, we recommend further investigation into the role of copper in TB pathogenesis to advance tuberculosis diagnosis and treatment and gain comprehensive insights into metal homeostasis in infectious disease contexts.

The co-infection of human immunodeficiency virus type 1 (HIV-1) and tuberculosis poses a lethal threat. Currently, our understanding of the altered immune responses and diverse immune cell subpopulations triggered by dual pathogen infections remains inadequate.

We utilized single-cell RNA sequencing data from the Gene Expression Omnibus database and the China National GeneBank Nucleotide Sequence Archive to study peripheral blood mononuclear cells from individuals infected with HIV-1 and those co-infected with Mycobacterium tuberculosis (Mtb)/HIV. We investigated cellular components, signaling pathways, biological functions, developmental trajectories, and gene regulatory networks among different cells to determine cellular heterogeneity in the progression of Mtb/HIV co-infection.

We constructed a single-cell global transcriptional landscape of Mtb/HIV co-infection, revealing heterogeneity among various cell subpopulations. CD4+ T_RACK1_STAT1 subpopulation may participate in the JAK-STAT signaling pathway through RACK1-mediated transcriptional regulation of STAT1, potentially mediating the immune response in patients. Targeting CD8+ T_RACK1_TIGIT subpopulation via RACK1 may help restore the effector capacity of CD8+ T cells. Additionally, Mono_HSP90AA1 and Mono_APOBEC3A subpopulations were positioned at the endpoints of monocyte differentiation trajectories in different patients, suggesting their significant roles in distinct types of immune responses. CTL_GNLY and NK_HSPA1A subpopulations were specifically enriched in three distinct HIV-infected patient groups, indicating their crucial roles in the immune cytotoxicity associated with Mtb/HIV co-infection.

The immune system disruptions caused by HIV-1 infection are further exacerbated by co-infection with Mtb. This compounded effect leads to significant heterogeneity in immune cell subpopulations among co-infected individuals, promoting immune system dysfunction.

Multidrug-resistant tuberculosis (MDR-TB) poses a significant global health threat, especially when it involves the central nervous system (CNS). Tuberculous meningitis (TBM), a severe manifestation of TB, is linked to high mortality rates and long-term neurological complications, further exacerbated by drug resistance and immune evasion mechanisms employed by Mycobacterium tuberculosis (Mtb). Although pulmonary TB remains the primary focus of research, MDR-TBM introduces unique challenges in diagnosis, treatment, and patient outcomes. The effectiveness of current treatments is frequently compromised by poor CNS penetration of anti-TB drugs and the necessity for prolonged therapy, which often involves considerable toxicity. This review explores the potential of cytokine-based adjunct immunotherapies for MDR-TBM, addressing the challenges of balancing pro-inflammatory and anti-inflammatory signals within the CNS. A central focus is the prospective role of glutathione, not only in reducing oxidative stress but also in enhancing host immune defenses against Mtb's immune evasion strategies. Furthermore, the development of vaccines aimed at upregulating glutathione synthesis in macrophages represents a promising strategy to bolster the immune response and improve treatment outcomes. By integrating glutathione and innovative vaccine approaches into MDR-TBM management, this review proposes a comprehensive strategy that targets Mtb directly while supporting immune modulation, with the potential to enhance patient outcomes and reduce treatment related adverse effects. We underscore the urgent need for further research into adjunctive therapies and immunomodulatory strategies to more effectively combat MDR-TBM.

Bacterial infections have accompanied humanity for centuries. The discovery of the first antibiotics and the subsequent golden era of their discovery temporarily shifted the balance in this confrontation to the side of humans. Nevertheless, the excessive and improper use of antibacterial drugs and the evolution of bacteria has gotten the better of humans again. Therefore, today, the search for new antibacterial drugs or the development of alternative approaches to the prevention and treatment of bacterial infections is relevant and topical again. Vaccination is one of the most effective strategies for the prevention of bacterial infections. The success of new-generation vaccines, such as mRNA vaccines, in the fight against viral infections has prompted many researchers to design mRNA vaccines against bacterial infections. Nevertheless, the biology of bacteria and their interactions with the host's immunity are much more complex compared to viruses. In this review, we discuss structural features and key mechanisms of evasion of an immune response for nine species of bacterial pathogens against which mRNA vaccines have been developed and tested in animals. We focus on the results of experiments involving the application of mRNA vaccines against various bacterial pathogens in animal models and discuss possible options for improving the vaccines' effectiveness. This is one of the first comprehensive reviews of the use of mRNA vaccines against bacterial infections in vivo to improve our knowledge.

Antimicrobial photodynamic therapy (aPDT) emerges as a viable treatment strategy for infections resistant to conventional antibiotics. A complex interplay of factors, including intracellular photosensitizer (PS) accumulation, photochemical reaction type, and oxygen levels, determines the efficacy of aPDT. Recent progress includes the development of modified PSs with enhanced lipophilicity and target-specific strategies to improve bacterial cell wall penetration and targeting. Nanotechnology-based approaches, such as using nanomaterials for targeted PS delivery, have shown promise in enhancing aPDT efficacy. Advancements in light delivery methods for aPDT, such as transillumination of large lesions and local light delivery using fiber optic techniques, are also being explored to optimize treatment efficacy in clinical settings. The limited number of animal models and clinical trials specifically designed to assess the efficacy of aPDT for lung infections highlights the need for further research in this critical area. The potential prospects of aPDT for lung tissue infections originating from antibiotic-resistant bacterial infections are also discussed in this review.

Survival in host macrophages is an effective strategy for pathogenic bacterial transmission and pathogenesis. Our previous study found that viable but non-culturable (VBNC) Cronobacter Sakazakii (C. sakazakii) can survive in macrophages, but its survival mechanism is not clear. In this study, we investigated the possible mechanisms of VBNC C. sakazakii survival in macrophages in terms of environmental tolerance within macrophages and evasion of macrophages recognition. The results revealed that VBNC C. sakazakii survived under oxidative conditions at a higher rate than the culturable C. sakazakii. Moreover, the stringent response gene (relA and spoT) and the antioxidant-related genes (sodA, katG, and trxA) were up-regulated, indicating that VBNC C. sakazakii may regulate antioxidation through stringent response. On the other hand, compared with culturable C. sakazakii, VBNC C. sakazakii caused reduced response (Toll-like receptor 4) in macrophages, which was attributed to the suppression of biosynthesis of the lipopolysaccharides (LPS). Furthermore, we found that ellagic acid can reduce the survival rate of bacteria in macrophages by improving the immune TLR4 recognition ability of macrophages. In conclusion, VBNC C. sakazakii may survive in macrophages by regulating oxidative tolerance through stringent response and altering LPS synthesis to evade TLR4 recognition by macrophages, which suggests the pathogenic risk of VBNC C. sakazakii.

Tuberculosis (TB) represents a global public health threat and is a leading cause of morbidity and mortality worldwide. Effective control of TB is complicated with the emergence of multidrug resistance. Yet, there is a fundamental gap in understanding the complex and dynamic interactions between different Mycobacterium tuberculosis strains and the host. In this pilot study, we investigated the host immune response to different M. tuberculosis strains, including drug-sensitive avirulent or virulent, and rifampin-resistant or isoniazid-resistant virulent strains in human THP-1 cells. We identified major differences in the gene expression profiles in response to infection with these strains. The expression of IDO1 and IL-1β in the infected cells was stronger in all virulent M. tuberculosis strains. The most striking result was the overexpression of many interferon-stimulated genes (ISGs) in cells infected with the isoniazid-resistant strain, compared to the rifampin-resistant and the drug-sensitive strains. Our data indicate that infection with the isoniazid-resistant M. tuberculosis strain preferentially resulted in cGAS-STING/STAT1 activation, which induced a characteristic host immune response. These findings reveal complex gene signatures and a dynamic variation in the immune response to infection by different M. tuberculosis strains.

Nanotechnology has emerged as a promising field for the diagnosis, monitoring, and treatment of respiratory tract infections (RTIs). By leveraging the unique properties of nanoscale delivery systems, nanotechnology can significantly enhance the selectivity and efficacy of antimicrobials, thereby reducing off-target effects.

This review explores the development and application of targeted nanosystems in combating viral, bacterial, and fungal RTIs. Nanotechnology-based systems, including biological and non-biological nanoparticles, offer innovative solutions for overcoming antimicrobial resistance, improving drug bioavailability, and minimizing systemic side effects. RTIs are a leading cause of morbidity and mortality globally, particularly affecting vulnerable populations such as children, the elderly, and immunocompromised individuals. Traditional drug delivery methods face numerous challenges, such as rapid clearance, poor tissue penetration, and drug degradation. Nanoparticle-based delivery systems address these issues by enhancing tissue penetration, providing sustained drug release, and enabling targeted delivery to infection sites. These systems include liposomal delivery, polymeric nanoparticles, dendrimers, and metal-based nanoparticles, each offering unique advantages in treating RTIs. Nanotechnology also plays a crucial role in vaccine development by offering new strategies to enhance immune responses and improve antigen delivery. Furthermore, the review discusses the clinical translation and regulatory considerations for nanotechnology-based drug delivery, emphasizing the need for rigorous testing and quality control to ensure safety and efficacy.

Nanotechnology offers promising advancements in the treatment, and prevention of RTIs by enhancing drug delivery and efficacy. By addressing challenges such as antimicrobial resistance and poor tissue penetration, nanotechnology-based systems have the potential to significantly improve patient outcomes.

Brucellosis is a serious zoonosis caused by Brucella spp. infection, which not only seriously jeopardizes the health of humans and mammals, but also causes huge economic losses to the livestock industry. Brucella is a Gram-negative intracellular bacterium that relies primarily on its virulence factors and a variety of evolved survival strategies to replicate and proliferate within cells. Currently, the mechanisms of autophagy, inflammation, and apoptosis in Brucella-infected hosts are not fully understood and require further research and discussion. This review focuses on the relationship between Brucella and autophagy, inflammation, and apoptosis to provide the scientific basis for revealing the pathogenesis of Brucella.

Phagocytosis of Mycobacterium tuberculosis (Mtb) followed by its integration into the matured lysosome is critical in the host defense against tuberculosis. How Mtb escapes this immune attack remains elusive. In this study, we unveiled a novel regulatory mechanism by which SIRT7 regulates cytoskeletal remodeling by modulating RAC1 activation. We discovered that SIRT7 expression was significantly reduced in CD14+ monocytes of TB patients. Mtb infection diminished SIRT7 expression by macrophages at both the mRNA and protein levels. SIRT7 deficiency impaired actin cytoskeleton-dependent macrophage phagocytosis, LC3II expression, and bactericidal activity. In a murine tuberculosis model, SIRT7 deficiency detrimentally impacted host resistance to Mtb, while Sirt7 overexpression significantly increased the host defense against Mtb, as determined by bacterial burden and inflammatory-histopathological damage in the lung. Mechanistically, we demonstrated that SIRT7 limits Mtb infection by directly interacting with and activating RAC1, through which cytoskeletal remodeling is modulated. Therefore, we concluded that SIRT7, in its role regulating cytoskeletal remodeling through RAC1, is critical for host responses during Mtb infection and proposes a potential target for tuberculosis treatment.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health issue. Critical to macrophages' defense against Mtb is phagocytosis, governed by the actin cytoskeleton. Previous research has revealed that Mtb manipulates and disrupts the host's actin network, though the specific mechanisms have been elusive. Our study identifies a pivotal role for SIRT7 in this context: Mtb infection leads to reduced SIRT7 expression, which, in turn, diminishes RAC1 activation and consequently impairs actin-dependent phagocytosis. The significance of our research is that SIRT7 directly engages with and activates Rac Family Small GTPase 1 (RAC1), thus promoting effective phagocytosis and the elimination of Mtb. This insight into the dynamic between host and pathogen in TB not only broadens our understanding but also opens new avenues for therapeutic development.

Tuberculosis (TB), induced by Mycobacterium tuberculosis (Mtb) infection, remains a major public health issue worldwide. Mtb has developed complicated strategies to inhibit the immunological clearance of host cells, which significantly promote TB epidemic and weaken the anti-TB treatments. Host-directed therapy (HDT) is a novel approach in the field of anti-infection for overcoming antimicrobial resistance by enhancing the antimicrobial activities of phagocytes through phagosomal maturation, autophagy and antimicrobial peptides. Autophagy, a highly conserved cellular event within eukaryotic cells that is effective against a variety of bacterial infections, has been shown to play a protective role in host defense against Mtb. In recent decades, the introduction of nanomaterials into medical fields open up a new scene for novel therapeutics with enhanced efficiency and safety against different diseases. The active modification of nanomaterials not only allows their attractive targeting effects against the host cells, but also introduce the potential to regulate the host anti-TB immunological mechanisms, such as apoptosis, autophagy or macrophage polarization. In this review, we introduced the mechanisms of host cell autophagy for intracellular Mtb clearance, and how functional nanomaterials regulate autophagy for disease treatment. Moreover, we summarized the recent advances of nanomaterials for autophagy regulations as novel HDT strategies for anti-TB treatment, which may benefit the development of more effective anti-TB treatments.

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems have gained attention for their revolutionary potential in tuberculosis (TB) management, providing a novel approach to both diagnostics and treatment. This technology, renowned for its ability to accurately target and modify genetic material, offers a promising solution to the limitations of current TB diagnostic methods, which often rely on time-consuming culture techniques or polymerase chain reaction (PCR)-based assays. One of the key advantages of CRISPR-Cas systems is their high specificity and sensitivity, making them well-suited for detecting Mycobacterium tuberculosis, even in low-bacterial-load samples. Techniques such as CRISPR-Cas12 and Cas13 have been employed for rapid detection, utilizing their trans-cleavage activity to produce a fluorescent signal upon recognition of the TB genome. Furthermore, these methods often use isothermal amplification techniques like recombinase polymerase amplification (RPA) or loop-mediated isothermal amplification (LAMP), which require less equipment compared to traditional PCR. Beyond diagnostics, CRISPR-Cas technologies show promise in studying TB resistance mechanisms and potentially treating drug-resistant strains. Genome-editing capabilities enable researchers to manipulate the M. tuberculosis genome, investigating genes linked to virulence or antibiotic resistance. Although challenges such as the development of multiplexed CRISPR assays for detecting multiple mutations simultaneously remain, advancements continue to improve the technology's practicality for clinical use. Incorporating CRISPR into TB management could enhance early detection, inform personalized treatment, and potentially contribute to developing more effective therapies, especially in regions where TB remains a significant public health threat.

Tuberculosis (TB) remains the leading cause of deaths among infectious diseases worldwide. Cutaneous Tuberculosis (CTB), caused by Mycobacterium tuberculosis (Mtb) infection in the skin, is still a harmful public health issue that requires more effective treatment strategy. Herein, we introduced mannose-modified mesoporous polydopamine nanosystems (Man-mPDA NPs) as the macrophage-targeted vectors to deliver anti-TB drug rifampicin and as photothermal agent to facilitate photothermal therapy (PTT) against Mtb infected macrophages for synergistic treatment of CTB. Based on the selective macrophage targeting effects, the proposed Rif@Man-mPDA NPs also showed excellent photothermal properties to develop Rif@Man-mPDA NPs-mediated PTT for intracellular Mtb killings in macrophages. Importantly, Rif@Man-mPDA NPs could inhibit the immune escape of Mtb by effectively chelating intracellular Fe2+ and inhibiting lipid peroxidation, and up-regulating GPX4 expression to inhibit ferroptosis of Mtb infected macrophages through activating Nrf2/HO-1 signaling. Moreover, Rif@Man-mPDA NPs-mediated PTT could effectively activate host cell immune responses by promoting autophagy of Mtb infected macrophages, which thus synergizes targeted drug delivery and ferroptosis inhibition for more effective intracellular Mtb clearance. This Rif@Man-mPDA NPs-mediated PTT strategy could also effectively inhibit the Mtb burdens and alleviate the pathological lesions induced by Mtb infection without significant systemic side effects in mouse CTB model. These results indicate that Rif@Man-mPDA NPs-mediated PTT can be served as a novel anti-TB strategy against CTB by synergizing macrophage targeted photothermal therapy and host immune defenses, thus holding promise for more effective treatment strategy development against CTB.

Mycobacterium tuberculosis (M. tb) is a significant intracellular pathogen responsible for numerous infectious disease-related deaths worldwide. It uses ESX-1 T7SS to damage phagosomes and to enter the cytosol of host cells after phagocytosis. During infection, M. tb and host mitochondria release dsDNA, which activates the CGAS-STING1 pathway. This pathway leads to the production of type I interferons and proinflammatory cytokines and activates autophagy, which targets and degrades bacteria within autophagosomes. However, the role of type I IFNs in immunity against M. tb is controversial. While previous research has suggested a protective role, recent findings from cgas-sting1 knockout mouse studies have contradicted this. Additionally, a study using knockout mice and non-human primate models uncovered a new mechanism by which neutrophils recruited to lung infections form neutrophil extracellular traps. Activating plasmacytoid dendritic cells causes them to produce type I IFNs, which interfere with the function of interstitial macrophages and increase the likelihood of tuberculosis. Notably, M. tb uses its virulence proteins to disrupt the CGAS-STING1 signaling pathway leading to enhanced pathogenesis. Investigating the CGAS-STING1 pathway can help develop new ways to fight tuberculosis.

Traditional vaccines have played an important role in the prevention and treatment of infectious diseases, but they still have problems such as low immunogenicity, poor stability, and difficulty in inducing lasting immune responses. In recent years, the nucleic acid vaccine has emerged as a relatively cheap and safe new vaccine. Compared with traditional vaccines, nucleic acid vaccine has some unique advantages, such as easy production and storage, scalability, and consistency between batches. However, the direct administration of naked nucleic acid vaccine is not ideal, and safer and more effective vaccine delivery systems are needed. With the rapid development of nanocarrier technology, the combination of gene therapy and nanodelivery systems has broadened the therapeutic application of molecular biology and the medical application of biological nanomaterials. Nanoparticles can be used as potential drug-delivery vehicles for the treatment of hereditary and infectious diseases. In addition, due to the advantages of lung immunity, such as rapid onset of action, good efficacy, and reduced adverse reactions, pulmonary delivery of nucleic acid vaccine has become a hot spot in the field of research. In recent years, lipid nanocarriers have become safe, efficient, and ideal materials for vaccine delivery due to their unique physical and chemical properties, which can effectively reduce the toxic side effects of drugs and achieve the effect of slow release and controlled release, and there have been a large number of studies using lipid nanocarriers to efficiently deliver target components into the body. Based on the delivery of tuberculosis (TB) nucleic acid vaccine by lipid carrier, this article systematically reviews the advantages and mechanism of liposomes as a nucleic acid vaccine delivery carrier, so as to lay a solid foundation for the faster and more effective development of new anti-TB vaccine delivery systems in the future.

The Mycobacterium tuberculosis variant bovis (M. bovis) is a highly pathogenic environmental microorganism that causes bovine tuberculosis (bTB), a significant zoonotic disease. Currently, "test and culling" is the primary measure for controlling bTB, but it has been proven to be inadequate in animals due to their high susceptibility to the pathogen. Selective breeding for increased host resistance to bTB to reduce its prevalence is feasible. In this study, we found a vital host-dependent factor, RBMX2, that can potentially promote M. bovis infection. By knocking RBMX2 out, we investigated its function during M. bovis infection. Through transcriptome sequencing and alternative splicing transcriptome sequencing, we concluded that after M. bovis infection, embryo bovine lung (EBL) cells were significantly enriched in RNA splicing associated with apoptosis compared with wild-type EBL cells. Through protein/molecular docking, molecular dynamics simulations, and real-time quantitative PCR, we demonstrated that RBMX2 promotes the apoptosis of epithelial cells by upregulating and binding to apoptotic peptidase activating factor 1 (APAF-1), resulting in the alternative splicing of APAF-1 as a retention intron. To our knowledge, this is the first report of M. bovis affecting host epithelial cell apoptosis by hijacking RBMX2 to promote the intron splicing of downstream APAF-1. These findings may represent a significant contribution to the development of novel TB prevention and control strategies.

This study aimed to investigate the differential expression levels of the cGAS-STING pathway in peripheral blood mononuclear cells (PBMCs) of spinal tuberculosis (TB) patients with different progression and its feasibility as a diagnostic marker.

Peripheral blood and medical records of 25 patients with spinal TB and 10 healthy individuals, were prospectively collected and analyzed. PBMCs and serum were extracted from peripheral blood and the expression levels of the cGAS-STING pathway in PBMCs were measured by real-time PCR (RT-PCR) and serum interferon β (IFN-β) expression levels were measured by enzyme-linked immunosorbent assay (ELISA). The expression of Interferon regulatory Factor 3 (IRF3) in PBMCs was measured using western blot. Statistical analysis was performed using the SPSS 26.0 statistical package.

The results showed that the expression level of the TANK-binding kinase 1 (TBK1) and IRF3 was significantly higher in PBMCs (P < 0.05), in patients with active lesions than in patients with stable lesions. The serum concentration of IFN-β was significantly higher in patients with active lesions (P = 0.028). Compared with healthy individuals, the expression level of the cGAS-STING pathway was elevated in PBMCs of TB patients (P < 0.05), and the difference in the expression level of IFN-β was not statistically significant (P > 0.05), and the serum IFN-β concentration was elevated (P < 0.05). The calculated AUC values for TBK1 and IRF3 in PBMCs, IFN-β in serum and erythrocyte sedimentation rate (ESR) to distinguish between patients with active and stable lesions were 0.732, 0.714, 0.839, and 0.714 respectively.

The expression level of TBK1 and IRF3 in PBMCs, and IFN-β in the serum of patients with spinal TB is positively correlated with disease activity. TBK1 has higher specificity and IFN-β in serum has higher sensitivity when used to differentiate between patients with active and stable lesions.

Nutrients are absorbed by special transport proteins on the cell membrane; however, there is less information regarding transporters across the mycobacterial outer envelope, which comprises dense and intricate structures. In this study, we focus on the model organism Mycolicibacterium smegmatis, which has a cell envelope similar to that of Mycobacterium tuberculosis, as well as on the TiME protein secretion tube across the mycobacterial outer envelope. We present transcriptome results and analyze the protein compositions of a mycobacterial surface envelope, determining that more transporters and porins are induced to complement the deletion of the time gene in Mycolicibacterium smegmatis. The TiME protein is essential for nutrient utilization, as demonstrated in the uptake experiments and growth on various monosaccharides or with amino acids as the sole carbon source. Its deletion caused bacteria to be more sensitive to anti-TB drugs and to show a growth defect at an acid pH level, indicating that TiME promotes the survival of M. smegmatis in antibiotic-containing and acidic environments. These results suggest that TiME tubes facilitate bi-directional processes for both protein secretion and nutrient uptake across the mycobacterial outer envelope.

Tuberculosis caused by the pathogen Mycobacterium tuberculosis leads to increased mortality and morbidity worldwide. The prevalence of highly drug-resistant strains has reinforced the need for greater understanding of host-pathogen interactions at the cellular and molecular levels. Our previous work demonstrated critical roles of calcium ion channels in regulating protective responses to mycobacteria. In this report, we deciphered the roles of inwardly rectifying K+ ion channel Kir2.1 in epithelial cells. Data showed that infection of epithelial cells (and macrophages) increases the surface expression of Kir2.1. This increased expression of Kir2.1 results in higher intracellular mycobacterial survival, as either inhibiting or knocking down Kir2.1 results in mounting of a higher oxidative burst leading to a significant attenuation of mycobacterial survival. Further, inhibiting Kir2.1 also led to increased expression of T cell costimulatory molecules accompanied with increased activation of MAP kinases and transcription factors nuclear factor κB and phosphorylated CREB. Furthermore, inhibiting Kir2.1 induced increased autophagy and apoptosis that could also contribute to decreased bacterial survival. Interestingly, an increased association of heat shock protein 70 kDa with Kir2.1 was observed. These results showed that mycobacteria modulate the expression and function of Kir2.1 in epithelial cells to its advantage.