MicroRNA-27a controls the intracellular survival of Mycobacterium tuberculosis by regulating calcium-associated autophagy

miR-146a is critical for orchestrating Mycobacterium fortuitum survival through anti-inflammatory and M2 macrophage responses in fish

The significance of microRNAs (miRNAs) in host response to non-tuberculoid mycobacteria like Mycobacterium fortuitum remains nascent. Using zebrafish kidney macrophages (ZFKM), we elucidate a novel function of miR-146a, orchestrated by the TLR-2-PI3K-NF-κB pathway, in M. fortuitum pathogenesis. We demonstrate that miR-146a facilitates anti-inflammatory response by targeting IRAK-1 and TRAF-6 in M. fortuitum-infected ZFKM. Moreover, miR-146a mitigates M1 macrophage activity by suppressing the iNOS-NO axis while enhancing M2-specific TGF-β mRNA expression and subsequent inhibition of M. fortuitum eradication. These findings collectively suggest that miR-146a diminishes macrophage-mediate M. fortuitum clearance. Our study provides novel insights into the intricate interplay between miRNAs and mycobacterial infections. We propose a mechanistic model wherein the TLR-2/NF-κB axis initiates miR-146a expression, which, in turn, suppresses irak-1 and traf-6, fostering the development of M2 macrophages. Consequently, this creates an anti-inflammatory environment conducive to M. fortuitumsurvival. Our findings provide novel insights into the intricate interplay between miRNAs and mycobacterial persistence, a concerning aspect of pathogenesis.

Innovative Strategies for Combating Multidrug-Resistant Tuberculosis: Advances in Drug Delivery Systems and Treatment

Multidrug-resistant tuberculosis (MDR-TB) is a significant public health challenge globally, exacerbated by the limited efficacy of existing therapeutic approaches, prolonged treatment duration, and severe side effects. As drug resistance continues to emerge, innovative drug delivery systems and treatment strategies are critical to combating this crisis. This review highlights the molecular mechanisms underlying resistance to drugs in Mycobacterium tuberculosis, such as genetic mutation, efflux pump activity, and biofilm formation, contributing to the persistence and difficulty in eradicating MDR-TB. Current treatment options, including second-line drugs, offer limited effectiveness, prompting the need for innovation of advanced therapies and drug delivery systems. The progression in drug discovery has resulted in the approval of innovative therapeutics, including bedaquiline and delamanid, amongst other promising candidates under investigation. However, overcoming the limitations of traditional drug delivery remains a significant challenge. Nanotechnology has emerged as a promising solution, with nanoparticle-based drug delivery systems offering improved bioavailability and targeted and controlled release delivery, particularly for pulmonary targeting and intracellular delivery to macrophages. Furthermore, the development of inhalable formulations and the potential of nanomedicines to bypass drug resistance mechanisms presents a novel approach to enhancing drug efficacy. Moreover, adjunctive therapies, including immune modulation and host-directed therapies, are being explored to improve treatment outcomes. Immunotherapies, such as cytokine modulation and novel TB vaccines, offer complementary strategies to the use of antibiotics in combating MDR-TB. Personalized medicine approaches, leveraging genomic profiling of both the pathogen and the host, offer promise in optimizing treatment regimens and minimizing drug resistance. This review underscores the importance of multidisciplinary approaches, combining drug discovery, advanced delivery system development, and immune modulation to address the complexities of treating MDR-TB. Continued innovation, global collaboration, and improved diagnostics are essential to developing practical, accessible, and affordable treatments for MDR-TB.

Exploring the regulatory role of small RNAs in modulating host-pathogen interactions: implications for bacterial and viral infections

MicroRNAs (miRNAs) and transfer RNA-derived stress-induced RNAs (tiRNAs) have emerged as crucial players in the post-transcriptional regulation of gene expression in various cellular processes, including immunity and host defense against infections. In recent years, increasing evidence has highlighted their complex role in influencing the host response during viral and bacterial infections. miRNAs have been shown to play multiple roles in host-pathogen interaction like TLR activation and altered disease virulence during bacterial infections. In the context of viral infections, miRNAs are involved in regulating viral replication, pathogenesis, and immune evasion. Similarly, tiRNAs have recently emerged as novel players in bacterial and viral infections such as modulating bacterial growth, adaptation to stress conditions, host antiviral responses, and impacting viral replication and pathogenesis. This review provides a comprehensive analysis of the potential of miRNA expression profiles as diagnostic biomarkers to differentiate between bacterial and viral infections. Further discusses the key pathways through which small RNAs regulate bacterial and viral infection-related diseases.

Furamidine-induced autophagy exerts an anti-mycobacterial effect in a SIRT1-pAMPK-FOXO3a-dependent manner by elevation of intracellular Ca2+ level expression

Mycobacterium tuberculosis (M. tb), the etiological agent of tuberculosis (TB), continues to be a major contributor to global mortality rates. To effectively combat this pandemic, TB control has to be enhanced in several areas, including point-of-care diagnostics, shorter and safer drug regimens, and preventative vaccination. The latest findings have highlighted autophagy as a host-defense mechanism that eradicates many invading bacteria, including M. tb. Thus, novel approaches like the stimulation of autophagy using various pharmaceutical drugs can be undertaken to deal with this noxious pathogen. The present study has been formulated to evaluate the anti-mycobacterial potential of Furamidine, a DNA minor groove binder (MGB). Initially, a non-cytotoxic concentration of Furamidine (10 µM) was used to assess its impact on the intracellular persistence of mycobacteria in differentiated THP-1 (dTHP-1) cells. Furamidine treatment compromised intracellular mycobacterial growth compared to control cells. Autophagy, a well-known host-defensive strategy, was investigated as a possible contributor to revealing the mechanism of action. Multiparametric approaches such as LC3-I to II conversion, protein level expression of different autophagic markers, and MDC staining were employed to study autophagic response that conclusively suggested the autophagy induction potential of Furamidine in dTHP-1 cells. Further, elevated LC3-II expression and increased autophagic vacuole accumulation under Baf-A1 treatment demonstrated the positive regulation of autophagic flux upon Furamidine treatment. Mechanistic investigations showed increased intracellular calcium (Ca2+) level expression, SIRT1, pAMPK, and FOXO3a activation upon its treatment. Inhibition of Ca2+ level expression suppressed Ca2+-mediated-FOXO3a level in Furamidine-treated cells. Furthermore, administering various inhibitors hampered the Furamidine-induced autophagy that impacted intracellular mycobacteria clearance. These results conclude that Furamidine triggered the Ca2+/pAMPK/SIRT1/FOXO3a pathway, causing less mycobacterial load in dTHP-1 cells.

Serum microRNA Biomarker Expression in HIV and TB: A Concise Overview

Non-coding RNAs (ncRNAs), specifically MicroRNAs or miRNAs, are now understood to be essential regulators in the complex field of gene expression. By selectively binding to certain mRNA targets, these tiny RNA molecules control the expression of genes, leading to mRNA degradation or translational repression. The discovery of miRNAs has significantly advanced biomedical research, particularly in elucidating the molecular mechanisms underlying various diseases and exploring innovative therapeutic approaches. Recent progress in miRNA research has provided insights into their biogenesis, functional roles, and potential clinical applications. Despite the absence of established methodologies for clinical implementation, miRNAs show great promise as diagnostic and therapeutic agents for a wide array of diseases. Their distinctive attributes, such as high specificity, sensitivity, and accessibility, position them as ideal candidates for biomarker development and targeted therapy. Achieving a comprehensive understanding of miRNA biology and functionality is crucial to fully harnessing their potential in medicine. Ongoing research efforts aim to unravel the intricate mechanisms of miRNA-mediated gene regulation and to develop novel approaches for utilizing miRNAs in disease diagnosis, prognosis, and treatment. This review provides a comprehensive analysis of current knowledge on miRNAs, focusing on their biogenesis, regulatory mechanisms, and potential clinical applications. By synthesizing existing evidence and highlighting key research findings, this review aims to inspire further exploration into the diverse roles of miRNAs in health and disease. Ultimately, this endeavour could result in the development of innovative miRNA-based diagnostic and therapeutic strategies.

Harnessing miRNAs: A Novel Approach to Diagnosis and Treatment of Tuberculosis

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.

The critical role of miRNA in bacterial zoonosis

The public's health and the financial sustainability of international societies remain threatened by bacterial zoonoses, with limited reliable diagnostic and therapeutic options available for bacterial diseases. Bacterial infections influence mammalian miRNA expression in host-pathogen interactions. In order to counteract bacterial infections, miRNAs participate in gene-specific expression and play important regulatory roles that rely on translational inhibition and target gene degradation by binding to the 3' non-coding region of target genes. Intriguingly, according to current studies, that exogenous miRNAs derived from plants could potentially serve as effective medicinal components sourced from traditional Chinese medicine plants. These exogenous miRNAs exhibit stable functionality in mammals and mimic the regulatory roles of endogenous miRNAs, illuminating the molecular processes behind the therapeutic effects of plants. This review details the immune defense mechanisms of inflammation, apoptosis, autophagy and cell cycle disturbance caused by some typical bacterial infections, summarizes the role of some mammalian miRNAs in regulating these mechanisms, and introduces the cGAS-STING signaling pathway in detail. Evidence suggests that this newly discovered immune defense mechanism in mammalian cells can also be affected by miRNAs. Meanwhile, some examples of transboundary regulation of mammalian mRNA and even bacterial diseases by exogenous miRNAs from plants are also summarized. This viewpoint provides fresh understanding of microbial tactics and host mechanisms in the management of bacterial illnesses.

A low-molecular-weight α-glucan from edible fungus Agaricus blazei Murrill activates macrophage TFEB-mediated antibacterial defense to combat implant-associated infection

Implant-associated infection (IAI) is a prevalent and potentially fatal complication of orthopaedic surgery. Boosting antibacterial immunity, particularly the macrophage-mediated response, presents a promising therapeutic approach for managing persistent infections. In this study, we successfully isolated and purified a homogeneous and neutral water-soluble polysaccharide, designated as AM-1, from the edible fungus Agaricus blazei Murrill. Structure analysis revealed that AM-1 (Mw = 3.87 kDa) was a low-molecular-weight glucan characterized by a primary chain of →4)-α-D-Glcp-(1 → and side chains that were linked at the O-6 and O-3 positions. In vivo assays showed that AM-1 effectively attenuated the progression of infection and mitigated infectious bone destruction in IAI mouse models. Mechanistically, AM-1 promotes intracellular autophagy-lysosomal biogenesis by inducing the nuclear translocation of transcription factor EB, finally enhancing the bactericidal capabilities and immune-modulatory functions of macrophages. These findings demonstrate that AM-1 significantly alleviates the progression of challenging IAIs as a presurgical immunoenhancer. Our research introduces a novel therapeutic strategy that employs natural polysaccharides to combat refractory infections.

Mycobacterium tuberculosis hijacks host macrophages-derived interleukin 16 to block phagolysosome maturation for enhancing intracellular growth

The discovery of promising cytokines and clarification of their immunological mechanisms in controlling the intracellular fate of Mycobacterium tuberculosis (Mtb) are necessary to identify effective diagnostic biomarkers and therapeutic targets. To escape immune clearance, Mtb can manipulate and inhibit the normal host process of phagosome maturation. Phagosome maturation arrest by Mtb involves multiple effectors and much remains unknown about this important aspect of Mtb pathogenesis. In this study, we found that interleukin 16 (IL-16) is elevated in the serum samples of Tuberculosis (TB) patients and can serve as a specific target for treatment TB. There was a significant difference in IL-16 levels among active TB, latent TB infection (LTBI), and non-TB patients. This study first revealed that macrophages are the major source of IL-16 production in response to Mtb infection, and elucidated that IL-16 can promote Mtb intracellular survival by inhibiting phagosome maturation and suppressing the expression of Rev-erbα which can inhibit IL-10 secretion. The experiments using zebrafish larvae infected with M. marinum and mice challenged with H37Rv demonstrated that reducing IL-16 levels resulted in less severe pathology and improved survival, respectively. In conclusion, this study provided direct evidence that Mtb hijacks the host macrophages-derived interleukin 16 to enhance intracellular growth. It is suggesting the immunosuppressive role of IL-16 during Mtb infection, supporting IL-16 as a promising therapeutic target.

TRPV2 calcium channel promotes breast cancer progression potential by activating autophagy

Breast cancer, the most prevalent and aggressive tumor affecting women, requires identification of disease determinants to facilitate the development of effective therapeutic strategies. Transient receptor potential vanilloid 2 (TRPV2), an ion channel highly permeable for calcium (Ca2+), is implicated in physiological and pathological processes. Nevertheless, the role of TRPV2 in breast cancer remains poorly elucidated. In this study, we found high levels of TRPV2 expression associated with advanced malignancy, thereby suggesting its potential as a biomarker for breast cancer staging. We demonstrated that TRPV2 activation promotes breast cancer cell proliferation, migration, and invasion, while silencing of TRPV2 suppresses breast cancer progression, highlighting the oncogenic role of TRPV2. Moreover, we reveal that TRPV2 facilitates cancer progression by modulating the CaMKKβ/AMPK/ULK1-autophagic axis through mediating calcium influx, providing new insights into TRPV2 as a novel therapeutic target for breast cancer treatment.

Low frequency sinusoidal electromagnetic fields promote the osteogenic differentiation of rat bone marrow mesenchymal stem cells by modulating miR-34b-5p/STAC2

Electromagnetic fields (EMFs) have emerged as an effective treatment for osteoporosis. However, the specific mechanism underlying their therapeutic efficacy remains controversial. Herein, we confirm the pro-osteogenic effects of 15 Hz and 0.4-1 mT low-frequency sinusoidal EMFs (SEMFs) on rat bone marrow mesenchymal stem cells (BMSCs). Subsequent miRNA sequencing reveal that miR-34b-5p is downregulated in both the 0.4 mT and 1 mT SEMFs-stimulated groups. To clarify the role of miR-34b-5p in osteogenesis, BMSCs are transfected separately with miR-34b-5p mimic and inhibitor. The results indicate that miR-34b-5p mimic transfection suppress osteogenic differentiation, whereas inhibition of miR-34b-5p promote osteogenic differentiation of BMSCs. In vivo assessments using microcomputed tomography, H&E staining, and Masson staining show that miR-34b-5p inhibitor injections alleviate bone mass loss and trabecular microstructure deterioration in ovariectomy (OVX) rats. Further validation demonstrates that miR-34b-5p exerts its effects by regulating STAC2 expression. Modulating the miR-34b-5p/STAC2 axis attenuate the pro-osteogenic effects of low-frequency SEMFs on BMSCs. These studies indicate that the pro-osteogenic effect of SEMFs is partly due to the regulation of the miR-34b-5p/STAC2 pathway, which provides a potential therapeutic candidate for osteoporosis.

Environmental endocrine disrupting chemical 4-tert-butylphenol induced calcium overload and subsequent autophagy impairment via miRNA-363/CACNA1D Axis in epithelioma papulosum cyprini cells

Environmental endocrine disrupting chemical 4-tert-butylphenol (4-tBP), a widely-utilized surfactant in various industries, poses potential risks to aquatic organisms. Our previous sequencing results suggested that 4-tBP-induced common carp liver injury might be associated with Ca2+ signaling and autophagy. However, the intricate involvement of these pathways in 4-tBP-induced cytotoxic mechanisms remained unexplored. To bridge these knowledge gaps, this study focused on epithelioma papulosum cyprini (EPC) cells, a significant cell type in fish biology. Initial observations showed that 4-tBP induced a dose-dependent perturbation in Ca2+ levels. Further investigations, with siRNA and L-type Ca2+ channel agonist (BAYK8644), identified L-type calcium channel gene CACNA1D as a critical regulator of 4-tBP-induced Ca2+ overload. Predictive analysis using miRanda platform suggested a potential interaction between miR-363 and CACNA1D, which was subsequently verified through dual-luciferase reporter gene assays. We then established miR-363 mimic/inhibitor models, along with miR-363 and CACNA1D co-suppression models in EPC cells. Through TEM observation, immunofluorescence assay, Ca2+ staining, and qRT-PCR analysis, we evaluated the role of miR-363/CACNA1D axis in modulating the effects of 4-tBP on Ca2+ signaling and autophagy. Results showed that miR-363 inhibitor exacerbated 4-tBP-induced increase in CALM2, CAMKII, Calpain2, and p62 expression and also led to decrease in ATG5, ATG7, and LC3b expression. In contrast, miR-363 mimic notably alleviated these changes. Notably, siRNA CACNA1D effectively modulating miR-363 inhibitor's effect. Our study revealed that 4-tBP induced Ca2+ overload and subsequent autophagy impairment via miR-363/CACNA1D axis. These findings illuminated a profound understanding of molecular mechanisms underlying 4-tBP-induced cytotoxicity and spotlighted a potential therapeutic target.

Mycobacterium tuberculosis and host interactions in the manifestation of tuberculosis

The final step of epigenetic processes is changing the gene expression in a new microenvironment in the body, such as neuroendocrine changes, active infections, oncogenes, or chemical agents. The case of tuberculosis (TB) is an outcome of Mycobacterium tuberculosis (M.tb) and host interaction in the manifestation of active and latent TB or clearance. This comprehensive review explains and interprets the epigenetics findings regarding gene expressions on the host-pathogen interactions in the development and progression of tuberculosis. This review introduces novel insights into the complicated host-pathogen interactions, discusses the challengeable results, and shows the gaps in the clear understanding of M.tb behavior. Focusing on the biological phenomena of host-pathogen interactions, the epigenetic changes, and their outcomes provides a promising future for developing effective TB immunotherapies when converting gene expression toward appropriate host immune responses gradually becomes attainable. Overall, this review may shed light on the dark sides of TB pathogenesis as a life-threatening disease. Therefore, it may support effective planning and implementation of epigenetics approaches for introducing proper therapies or effective vaccines.

Functional Analysis of Genes in Mycobacterium tuberculosis Action Against Autophagosome-Lysosome Fusion

Tuberculosis is a lethal disease that is one of the world's top ten death-associated infections in humans; Mycobacterium tuberculosis causes tuberculosis, and this bacterium is linked to the lysis of autophagolysosomal fusion action, a self-defense mechanism of its own. Thus, Cytoplasmic bacilli are sequestered by autophagy and transported to lysosomes to be inactivated to destroy intracellular bacteria. Besides this, a macrophage can limit intracellular Mycobacterium by using a type of autophagy, selective autophagy, a cell that marks undesirable ubiquitin existence in cytosolic cargo, acting as a "eat me" sensor in conjunction with cellular homeostasis. Mycobacterium tuberculosis genes of the PE_PGRS protein family inhibit autophagy, increase mycobacterial survival, and lead to latent tuberculosis infection associated with miRNAs. In addition, the family of autophagy-regulated (ATG) gene members are involved in autophagy and controls the initiation, expansion, maturation, and fusion of autophagosomes with lysosomes, among other signaling events that control autophagy flux and reduce inflammatory responses and forward to promote cellular proliferation. In line with the formation of caseous necrosis in macrophages by Mycobacterium tuberculosis and their action on the lysis of autophagosome fusion, it leads to latent tuberculosis infection. Therefore, we aimed to comprehensively analyses the autophagy and self-defense mechanism of Mycobacterium tuberculosis, which is to be gratified future research on novel therapeutic tools and diagnostic markers against tuberculosis.

MicroRNA-144-3p Inhibits Host Lipid Catabolism and Autophagy by Targeting PPARα and ABCA1 During Mycobacterium Tuberculosis Infection

MicroRNA-mediated metabolic reprogramming recently has been identified as an important strategy for Mycobacterium tuberculosis (Mtb) to evade host immune responses. However, it is unknown what role microRNA-144-3p (miR-144-3p) plays in cellular metabolism during Mtb infection. Here, we report the meaning of miR-144-3p-mediated lipid accumulation for Mtb-macrophage interplay. Mtb infection was shown to upregulate the expression of miR-144-3p in macrophages. By targeting peroxisome proliferator-activated receptor α (PPARα) and ATP-binding cassette transporter A1 (ABCA1), miR-144-3p overexpression promoted lipid accumulation and bacterial survival in Mtb-infected macrophages, while miR-144-3p inhibition had the opposite effect. Furthermore, reprogramming of host lipid metabolism by miR-144-3p suppressed autophagy in response to Mtb infection. Our findings uncover that miR-144-3p regulates host metabolism and immune responses to Mtb by targeting PPARα and ABCA1, suggesting a potential host-directed tuberculosis therapy by targeting the interface of miRNA and lipid metabolism.

Mycobacterium tuberculosis resides in lysosome-poor monocyte-derived lung cells during chronic infection

Mycobacterium tuberculosis (Mtb) infects lung myeloid cells, but the specific Mtb-permissive cells and host mechanisms supporting Mtb persistence during chronic infection are incompletely characterized. We report that after the development of T cell responses, CD11clo monocyte-derived cells harbor more live Mtb than alveolar macrophages (AM), neutrophils, and CD11chi monocyte-derived cells. Transcriptomic and functional studies revealed that the lysosome pathway is underexpressed in this highly permissive subset, characterized by less lysosome content, acidification, and proteolytic activity than AM, along with less nuclear TFEB, a regulator of lysosome biogenesis. Mtb infection does not drive lysosome deficiency in CD11clo monocyte-derived cells but promotes recruitment of monocytes that develop into permissive lung cells, mediated by the Mtb ESX-1 secretion system. The c-Abl tyrosine kinase inhibitor nilotinib activates TFEB and enhances lysosome functions of macrophages in vitro and in vivo, improving control of Mtb infection. Our results suggest that Mtb exploits lysosome-poor lung cells for persistence and targeting lysosome biogenesis is a potential host-directed therapy for tuberculosis.

Identification of important modules and biomarkers in tuberculosis based on WGCNA

Background

Tuberculosis (TB) is a significant public health concern, particularly in China. Long noncoding RNAs (lncRNAs) can provide abundant pathological information regarding etiology and could include candidate biomarkers for diagnosis of TB. However, data regarding lncRNA expression profiles and specific lncRNAs associated with TB are limited.

Methods

We performed ceRNA-microarray analysis to determine the expression profile of lncRNAs in peripheral blood mononuclear cells (PBMCs). Weighted gene co-expression network analysis (WGCNA) was then conducted to identify the critical module and genes associated with TB. Other bioinformatics analyses, including Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and co-expression networks, were conducted to explore the function of the critical module. Finally, real-time quantitative polymerase chain reaction (qPCR) was used to validate the candidate biomarkers, and receiver operating characteristic analysis was used to assess the diagnostic performance of the candidate biomarkers.

Results

Based on 8 TB patients and 9 healthy controls (HCs), a total of 1,372 differentially expressed lncRNAs were identified, including 738 upregulated lncRNAs and 634 downregulated lncRNAs. Among all lncRNAs and mRNAs in the microarray, the top 25% lncRNAs (3729) and top 25% mRNAs (2824), which exhibited higher median expression values, were incorporated into the WGCNA. The analysis generated 16 co-expression modules, among which the blue module was highly correlated with TB. GO and KEGG analyses showed that the blue module was significantly enriched in infection and immunity. Subsequently, considering module membership values (>0.85), gene significance values (>0.90) and fold-change value (>2 or < 0.5) as selection criteria, the top 10 upregulated lncRNAs and top 10 downregulated lncRNAs in the blue module were considered as potential biomarkers. The candidates were then validated in an independent validation sample set (31 TB patients and 32 HCs). The expression levels of 8 candidates differed significantly between TB patients and HCs. The lncRNAs ABHD17B (area under the curve [AUC] = 1.000) and ENST00000607464.1 (AUC = 1.000) were the best lncRNAs in distinguishing TB patients from HCs.

Conclusion

This study characterized the lncRNA profiles of TB patients and identified a significant module associated with TB as well as novel potential biomarkers for TB diagnosis.

Host-directed therapy against mycobacterium tuberculosis infections with diabetes mellitus

Tuberculosis (TB) is caused by the bacterial pathogen Mycobacterium tuberculosis (MTB) and is one of the principal reasons for mortality and morbidity worldwide. Currently, recommended anti-tuberculosis drugs include isoniazid, rifampicin, ethambutol, and pyrazinamide. TB treatment is lengthy and inflicted with severe side-effects, including reduced patient compliance with treatment and promotion of drug-resistant strains. TB is also prone to other concomitant diseases such as diabetes and HIV. These drug-resistant and complex co-morbid characteristics increase the complexity of treating MTB. Host-directed therapy (HDT), which effectively eliminates MTB and minimizes inflammatory tissue damage, primarily by targeting the immune system, is currently an attractive complementary approach. The drugs used for HDT are repositioned drugs in actual clinical practice with relative safety and efficacy assurance. HDT is a potentially effective therapeutic intervention for the treatment of MTB and diabetic MTB, and can compensate for the shortcomings of current TB therapies, including the reduction of drug resistance and modulation of immune response. Here, we summarize the state-of-the-art roles and mechanisms of HDT in immune modulation and treatment of MTB, with a special focus on the role of HDT in diabetic MTB, to emphasize the potential of HDT in controlling MTB infection.

TRAF6 triggers Mycobacterium-infected host autophagy through Rab7 ubiquitination

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase that is extensively involved in the autophagy process by interacting with diverse autophagy initiation and autophagosome maturation molecules. However, whether TRAF6 interacts with lysosomal proteins to regulate Mycobacterium-induced autophagy has not been completely characterized. Herein, the present study showed that TRAF6 interacted with lysosomal key proteins Rab7 through RING domain which caused Rab7 ubiquitination and subsequently ubiquitinated Rab7 binds to STX17 (syntaxin 17, a SNARE protein that is essential for mature autophagosome), and thus promoted the fusion of autophagosomes and lysosomes. Furthermore, TRAF6 enhanced the initiation and formation of autophagosomes in Mycobacterium-induced autophagy in both BMDMs and RAW264.7 cells, as evidenced by autophagic flux, colocalization of LC3 and BCG, autophagy rates, and autophagy-associated protein expression. Noteworthy to mention, TRAF6 deficiency exacerbated lung injury and promoted BCG survival. Taken together, these results identify novel molecular and cellular mechanisms by which TRAF6 positively regulates Mycobacterium-induced autophagy.

Comparison of the in vitro antibacterial activity of ofloxacin, levofloxacin, moxifloxacin, sitafloxacin, finafloxacin, and delafloxacin against Mycobacterium tuberculosis strains isolated in China

Objective

The resistance of Mycobacterium tuberculosis (Mtb) to currently available fluoroquinolones (FQs), namely ofloxacin (OFX), levofloxacin (LFX), and moxifloxacin (MFX), renders the treatment of TB infections less successful. In this study, we aimed to evaluate the susceptibility and intracellular killing assay of Mtb to next-generation FQs in vitro and determine the correlation of FQs resistance and newly detected mutations in gyrB by molecular docking.

Methods

Antimicrobial susceptibility test was performed to determine the minimum inhibitory concentrations (MICs) of six FQs, including currently available FQs (OFX, LFX, and MFX) and next-generation FQs, i.e., sitafloxacin (SFX), finafloxacin (FIN) and delafloxacin (DFX) against Mtb clinical isolates obtained in 2015 and 2022, respectively. Quinolone-resistance-determining regions of gyrA and gyrB were subjected to DNA sequencing and the correlation of FQs resistance and new mutations in gyrB were determined by molecular docking. Furthermore, the intracellular antibacterial activity of the six FQs against Mtb H37Rv in THP-1 cells was evaluated.

Results

SFX exhibited the highest antibacterial activity against Mtb isolates (MIC90 = 0.25 μg/mL), whereas DFX and OFX exhibited comparable activity (MIC90 = 8 μg/mL). A statistically significant difference was observed among the MICs of the new generation FQs (SFX, P = 0.002; DFX, P = 0.008). Additionally, a marked increase in MICs was found in strains isolated in 2022 compared with those isolated in 2015. There might be correlation between FQs resistance and mutations in gyrB G520T and G520A. Cross-resistance rate between SFX and MFX was 40.6 % (26/64). At a concentration of 1 μg/mL, SFX exhibited high intracellular antibacterial activity (96.6 % ± 1.5 %) against the Mtb H37Rv, comparable with that of MFX at a concentration of 2 μg/mL.

Conclusion

SFX exhibits the highest inhibitory activity against Mtb in vitro and THP-1 cell lines, which exhibits partial-cross resistance with MFX. There might be correlation between FQs resistance and mutations in gyrB G520T and G520A.Our findings provide crucial insights into the potential clinical application of SFX and DFX in the treatment of Mtb infections.

Exploring and exploiting the host cell autophagy during Mycobacterium tuberculosis infection

Tuberculosis, caused by Mycobacterium tuberculosis, is a fatal infectious disease that prevails to be the second leading cause of death from a single infectious agent despite the availability of multiple drugs for treatment. The current treatment regimen involves the combination of several drugs for 6 months that remain ineffective in completely eradicating the infection because of several drawbacks, such as the long duration of treatment and the side effects of drugs causing non-adherence of patients to the treatment regimen. Autophagy is an intracellular degradative process that eliminates pathogens at the early stages of infection. Mycobacterium tuberculosis's unique autophagy-blocking capability makes it challenging to eliminate compared to usual pathogens. The present review discusses recent advances in autophagy-inhibiting factors and mechanisms that could be exploited to identify autophagy-inducing chemotherapeutics that could be used as adjunctive therapy with the existing first-line anti-TB agent to shorten the duration of therapy and enhance cure rates from multidrug-resistant tuberculosis (MDR-TB) and extreme drug-resistant tuberculosis (XDR-TB).

Genome-wide identification of candidate copy number polymorphism genes associated with complex traits of Tibetan-sheep

Copy number variation (CNV) is a genetic structural polymorphism important for phenotypic diversity and important economic traits of livestock breeds, and it plays an important role in the desired genetic variation. This study used whole genome sequencing to detect the CNV variation in the genome of 6 local Tibetan sheep groups. We detected 69,166 CNV events and 7230 copy number variable regions (CNVRs) after merging the overlapping CNVs, accounting for 2.72% of the reference genome. The CNVR length detected ranged from 1.1 to 1693.5 Kb, with a total length of 118.69 Mb and an average length of 16.42 Kb per CNVR. Functional GO cluster analysis showed that the CNVR genes were mainly involved in sensory perception systems, response to stimulus, and signal transduction. Through CNVR-based Vst analysis, we found that the CACNA2D3 and CTBP1 genes related to hypoxia adaptation, the HTR1A gene related to coat color, and the TRNAS-GGA and PIK3C3 genes related to body weight were all strongly selected. The findings of our study will contribute novel insights into the genetic structural variation underlying hypoxia adaptation and economically important traits in Tibetan sheep.

Evaluation of miR-let-7f, miR-125a, and miR-125b expression levels in sputum and serum samples of Iranians and Afghans with pulmonary tuberculosis

Background and Objectives

The role of microRNAs (miRNAs) in tuberculosis infection is well established. As microRNAs are able to change expression profiles according to different conditions, they can be useful biomarkers. Iranians and Afghans with tuberculosis were studied for three immune-related miRNAs (miR-let-7f, miR-125a, and miR-125b).

Materials and Methods

A total of 60 Iranian and Afghan patients with active pulmonary TB were enrolled in the Pulmonary Department of the Pasteur Institute of Iran. Serum and sputum samples were collected simultaneously from all participants. A Real-time PCR was conducted to detect differentially expressed miRNAs.

Results

Iranian (P<0.0001) and Afghan (P<0.0001) serum samples and Afghan (P<0.0001) sputum samples overexpressed miR-125a, whereas Iranian sputum samples showed downregulation (P=0.0039). In both Iranian (P<0.0001; P=0.0007) and Afghan (P<0.0001; P<0.0001) serum and sputum samples, miR-125b was overexpressed. Furthermore, miR-let-7f down-regulation was observed in serum and sputum samples (P<0.0001), whereas Iranian sputum samples had no statistically significant differences (P=0.348).

Conclusion

Overexpression of miR-125a and miR-125b has been detected in Iranian and Afghan samples. In both races, miR-let-7f downregulation has been confirmed. Identification of miRNA profiles under different conditions opens the door to evaluating potential new biomarkers for diagnosis, disease monitoring, and therapeutic markers in TB infection.

Harnessing host-pathogen interactions for innovative drug discovery and host-directed therapeutics to tackle tuberculosis

Tuberculosis (TB) is a highly contagious bacterial infection caused by Mycobacterium tuberculosis (Mtb), which has been ranked as the second leading cause of death worldwide from a single infectious agent. As an intracellular pathogen, Mtb has well adapted to the phagocytic host microenvironment, influencing diverse host processes such as gene expression, trafficking, metabolism, and signaling pathways of the host to its advantage. These responses are the result of dynamic interactions of the bacteria with the host cell signaling pathways, whereby the bacteria attenuate the host cellular processes for their survival. Specific host genes and the mechanisms involved in the entry and subsequent stabilization of M. tuberculosis intracellularly have been identified in various genetic and chemical screens recently. The present understanding of the co-evolution of Mtb and macrophage system presented us the new possibilities for exploring host-directed therapeutics (HDT). Here, we discuss the host-pathogen interaction for Mtb, including the pathways adapted by Mtb to escape immunity. The review sheds light on different host-directed therapies (HDTs) such as repurposed drugs and vitamins, along with their targets such as granuloma, autophagy, extracellular matrix, lipids, and cytokines, among others. The article also examines the available clinical data on these drug molecules. In conclusion, the review presents a perspective on the current knowledge in the field of HDTs and the need for additional research to overcome the challenges associated HDTs.

Macrophage targeted polymeric curcumin nanoparticles limit intracellular survival of Mycobacterium tuberculosis through induction of autophagy and augment anti-TB activity of isoniazid in RAW 264.7 macrophages

Rapid emergence of antibiotic resistance in tuberculosis has left us with limited resources to treat and manage multi drug resistant (MDR) cases of tuberculosis, prompting the development of novel therapeutics. Mycobacterium tuberculosis (MTB) perturbs the host protective pathways for its survival, therefore host directed therapeutic (HDT) interventions offer an attractive alternative strategy. Curcumin (CMN), the principle curcuminoid from Curcuma longa is known to have anti-TB activity against MDR strains of MTB in macrophages. We discovered that treatment of CMN induced autophagy in uninfected and MTB infected macrophages which was evident by conversion of LC3-I to LC3-II and degradation of p62. Inhibition of autophagy by a pharmacological inhibitor 3-MA resulted in significant inhibition of intracellular killing activity of CMN, suggesting the involvement of autophagy in intracellular clearance of MTB. Moreover, annexin v-FITC/PI staining data suggested induction of apoptosis in uninfected and MTB infected macrophages post CMN treatment. This finding was further corroborated by up-regulated expression of pro-apoptotic proteins, Bax, cleaved caspase-3 and PARP and diminished expression of anti-apoptotic protein Bcl-2 as evaluated by immunoblotting. Using GFP-MTB H37Rv and Lysotracker Red staining we demonstrated co-localization of GFP-MTB H37Rv containing phagosome to lysosome after CMN treatment, indicating enhanced phagosome lysosome fusion. Due to poor bioavailability of CMN, its clinical use is limited, therefore to overcome this issue, CMN was encapsulated in Poly(lactic-co-glycolic) acid (PLGA) shell, resulting in polymeric CMN nano particles (ISCurNP). Flow cytometric evaluation suggested >99% uptake of ISCurNP after 3h of treatment. In BALB/c mice, oral dose of ISCurNP resulted in 6.7-fold increase in the bioavailability compared to free CMN. Moreover, ISCurNP treatment resulted in significant decrease in the intracellular survival of MTB H37Rv through induction of autophagy. Adjunct action of ISCurNP and CMN in combination with isoniazid (INH) revealed >99% decrease in intracellular survival of MTB in macrophage as compared to ISCurNP, CMN or INH alone. In conclusion, our findings suggest the role of ISCurNP as novel host directed formulation to combat both sensitive and MDR strains of MTB by induction of autophagy.

Identification of autophagy-associated circRNAs in sepsis-induced cardiomyopathy of mice

Circular RNAs (circRNAs) play a role in sepsis-related autophagy. However, the role of circRNAs in autophagy after sepsis-induced cardiomyopathy (SICM) is unknown, so we explored the circRNA expression profiles associated with autophagy in an acute sepsis mouse model. At a dose of 10 mg/kg, mice were intraperitoneally administered with lipopolysaccharides. The myocardial tissue was harvested after 6 h for microarray analysis, qRT-PCR, and western blotting. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis were evaluated, and a competing endogenous RNA network was constructed, to evaluate the role of circRNAs related to autophagy in SICM. In total, 1,735 differently expressed circRNAs were identified in the LPS-treated group, including 990 upregulated and 745 downregulated circRNAs. The expression level of the autophagy-specific protein p62 decreased, while the ratio of LC3 II to LC3 I increased. Additionally, 309 mRNAs and 187 circRNAs were correlated with autophagy in myocardial tissue after SICM. Of these, 179 circRNAs were predicted to function as "miRNA sponges". Some distinctive circRNAs and mRNAs found by ceRNA analysis might be involved in autophagy in SICM. These findings provide insights into circRNAs and identified new research targets that may be used to further explore the pathogenesis of SICM.

Engineered high-strength biohydrogel as a multifunctional platform to deliver nucleic acid for ameliorating intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a leading cause of low back pain. The strategy of using functional materials to deliver nucleic acids provides a powerful tool for ameliorating IVDD. However, the immunogenicity of nucleic acid vectors and the poor mechanical properties of functional materials greatly limit their effects. Herein, antagomir-204-3p (AM) shows low immunogenicity and effectively inhibits the apoptosis of nucleus pulposus cells. Moreover, a high-strength biohydrogel based on zinc-oxidized sodium alginate-gelatin (ZOG) is designed as a multifunctional nucleic acid delivery platform. ZOG loaded with AM (ZOGA) exhibits great hygroscopicity, antibacterial activity, biocompatibility, and biodegradability. Moreover, ZOGA can be cross-linked with nucleus pulposus tissue to form a high-strength collagen network that improves the mechanical properties of the intervertebral disc (IVD). In addition, ZOGA provides an advantageous microenvironment for genetic expression in which AM can play an efficient role in maintaining the metabolic balance of the extracellular matrix. The results of the radiological and histological analyses demonstrate that ZOGA restores the height of the IVD, retains moisture in the IVD, and maintains the tissue structure. The ZOGA platform shows the sustained release of nucleic acids and has the potential for application to ameliorate IVDD, opening a path for future studies related to IVD.

Mycobacterium tuberculosis resides in lysosome-poor monocyte-derived lung cells during chronic infection

Mycobacterium tuberculosis (Mtb) persists in lung myeloid cells during chronic infection. However, the mechanisms allowing Mtb to evade elimination are not fully understood. Here, we determined that in chronic phase, CD11clo monocyte-derived lung cells termed MNC1 (mononuclear cell subset 1), harbor more live Mtb than alveolar macrophages (AM), neutrophils, and less permissive CD11chi MNC2. Transcriptomic and functional studies of sorted cells revealed that the lysosome biogenesis pathway is underexpressed in MNC1, which have less lysosome content, acidification, and proteolytic activity than AM, and less nuclear TFEB, a master regulator of lysosome biogenesis. Mtb infection does not drive lysosome deficiency in MNC1. Instead, Mtb recruits MNC1 and MNC2 to the lungs for its spread from AM to these cells via its ESX-1 secretion system. The c-Abl tyrosine kinase inhibitor nilotinib activates TFEB and enhances lysosome function of primary macrophages and MNC1 and MNC2 in vivo, improving control of Mtb infection. Our results indicate that Mtb exploits lysosome-poor monocyte-derived cells for in vivo persistence, suggesting a potential target for host-directed tuberculosis therapy.

Mycobacterium tuberculosis resides in lysosome-poor monocyte-derived lung cells during chronic infection

Mycobacterium tuberculosis (Mtb) infects cells in multiple lung myeloid cell subsets and causes chronic infection despite innate and adaptive immune responses. However, the mechanisms allowing Mtb to evade elimination are not fully understood. Here, using new methods, we determined that after T cell responses have developed, CD11clo monocyte-derived lung cells termed MNC1 (mononuclear cell subset 1), harbor more live Mtb compared to alveolar macrophages (AM), neutrophils, and less permissive CD11chi MNC2. Bulk RNA sequencing of sorted cells revealed that the lysosome biogenesis pathway is underexpressed in MNC1. Functional assays confirmed that Mtb-permissive MNC1 have less lysosome content, acidification, and proteolytic activity than AM, and less nuclear TFEB, a master regulator of lysosome biogenesis. Mtb infection does not drive lysosome deficiency in MNC1 in vivo. Instead, Mtb recruits MNC1 and MNC2 to the lungs for its spread from AM to these cell subsets as a virulence mechanism that requires the Mtb ESX-1 secretion system. The c-Abl tyrosine kinase inhibitor nilotinib activates TFEB and enhances lysosome function of primary macrophages in vitro and MNC1 and MNC2 in vivo, improving control of Mtb infection. Our results indicate that Mtb exploits lysosome-poor monocyte-derived cells for in vivo persistence, suggesting a potential target for host-directed tuberculosis therapy.

LncRNA NR_003508 Suppresses Mycobacterium tuberculosis-Induced Programmed Necrosis via Sponging miR-346-3p to Regulate RIPK1

Emerging evidence suggests that long non-coding RNAs (LncRNAs) are involved in Mtb-induced programmed necrosis. Among these LncRNAs, LncRNA NR_003508 is associated with LPS-induced acute respiratory distress syndrome. However, whether LncRNA NR_003508 contributes to Mtb-induced programmed necrosis remains undocumented. Firstly, the expression of LncRNA NR_003508 was determined using RT-qPCR and FISH. The protein expression of RIPK1, p-RIPK1, RIPK3, p-RIPK3, MLKL, and p-MLKL was measured by Western blot in RAW264.7 and mouse lung tissues. Furthermore, luciferase reporter assays and bioinformatics were used to predict specific miRNA (miR-346-3p) and mRNA (RIPK1) regulated by LncRNA NR_003508. In addition, RT-qPCR was used to detect the RIPK1 expression in TB patients and healthy peripheral blood. The flow cytometry assay was performed to detect cell necrosis rates. Here we show that BCG infection-induced cell necrosis and increased LncRNA NR_003508 expression. si-NR_003508 inhibited BCG/H37Rv-induced programmed necrosis in vitro or in vivo. Functionally, LncRNA NR_003508 has been verified as a ceRNA for absorbing miR-346-3p, which targets RIPK1. Moreover, RIPK1 expression was elevated in the peripheral blood of TB patients compared with healthy people. Knockdown of LncRNA NR_003508 or miR-346-3p overexpression suppresses cell necrosis rate and ROS accumulation in RAW264.7 cells. In conclusion, LncRNA NR_003508 functions as a positive regulator of Mtb-induced programmed necrosis via sponging miR-346-3p to regulate RIPK1. Our findings may provide a promising therapeutic target for tuberculosis.

MicroRNAs as Biomarkers of Active Pulmonary TB Course

The spread of drug-resistant forms of TB dictates the need for surgical treatment in the complex of anti-tuberculosis measures in Russia. Most often, surgical intervention is performed in the case of pulmonary tuberculoma or fibrotic cavitary tuberculosis (FCT). This study is devoted to the search for biomarkers that characterize the course of disease in surgical TB patients. It is assumed that such biomarkers will help the surgeon decide on the timing of the planned operation. A number of serum microRNAs, potential regulators of inflammation and fibrosis in TB, selected on the basis of PCR-Array analysis, were considered as biomarkers. Quantitative real time polymerase chain reaction and receiver operating curves (ROC) were used to verify Array data and to estimate the ability of microRNAs (miRNAs) to discriminate between healthy controls, tuberculoma patients, and FCT patients. The study showed that miR-155, miR-191 and miR-223 were differentially expressed in serum of tuberculoma with “decay” and tuberculoma without “decay” patients. Another combination (miR-26a, miR-191, miR-222 and miR-320) forms a set to differentiate between tuberculoma with “decay” and FCT. Patients with tuberculoma without “decay” diagnosis differ from those with FCT in serum expression of miR-26a, miR-155, miR-191, miR-222 and miR-223. Further investigations are required to evaluate these sets on a larger population so as to set cut-off values that could be applied in laboratory diagnosis.

The miR-100-5p Targets SMARCA5 to Regulate the Apoptosis and Intracellular Survival of BCG in Infected THP-1 Cells

Mycobacterium tuberculosis (M. tb) is the causative agent of tuberculosis (TB) that leads to millions of deaths each year. Extensive evidence has explored the involvement of microRNAs (miRNAs) in M. tb infection. Limitedly, the concrete function of microRNA-100-5p (miR-100-5p) in M. tb remains unexplored and largely elusive. In this study, using Bacillus Calmette-Guérin (BCG) as the model strain, we validated that miR-100-5p was significantly decreased in BCG-infected THP-1 cells. miR-100-5p inhibition effectively facilitated the apoptosis of infected THP-1 cells and reduced BCG survival by regulating the phosphatidylinositol 3-kinase/AKT pathway. Further, SMARCA5 was the target of miR-100-5p and reduced after miR-100-5p overexpression. Since BCG infection down-regulated miR-100-5p in THP-1 cells, the SMARCA5 expression was up-regulated, which in turn increased apoptosis through caspase-3 and Bcl-2 and, thereby, reducing BCG intracellular survival. Collectively, the study uncovered a new molecular mechanism of macrophage to suppress mycobacterial infection through miR-100-5p and SMARCA5 pathway.

Analysis of the noncoding RNA regulatory networks of H37Rv- and H37Rv△1759c-infected macrophages

Noncoding RNAs regulate the process of Mycobacterium tuberculosis (M. tb) infecting the host, but there is no simultaneous transcriptional information of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) and the global regulatory networks of non-coding RNA. Rv1759c, a virulence factor, is a member of protein family containing the proline-glutamic acid (PE) in M. tb, which can increase M. tb survival. To reveal the noncoding RNA regulatory networks and the effect of Rv1759c on non-coding RNA expression during M. tb infection, we collected samples of H37Rv- and H37Rv△1759c-infected macrophages and explored the full transcriptome expression profile. We found 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv infection, 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv△1759c infection. We constructed lncRNA/circRNA-miRNA-mRNA regulatory networks during H37Rv and H37Rv△1759c infection. We demonstrated the role of one of the hubs of the networks, hsa-miR-181b-3p, for H37Rv survival in macrophages. We discovered that the expression changes of 68 mRNAs, 92 lncRNAs, 26 circRNAs, and 3 miRNAs were only related to the deletion of Rv1759c by comparing the transcription profiles of H37Rv and H37Rv△1759c. Here, our study comprehensively characterizes the transcriptional profiles in THP1-derived-macrophages infected with H37Rv and H37Rv△1759c, which provides support and new directions for in-depth exploration of noncoding RNA and PE/PPE family functions during the infection process.

Mouse Models for Mycobacterium tuberculosis Pathogenesis: Show and Do Not Tell

Science has been taking profit from animal models since the first translational experiments back in ancient Greece. From there, and across all history, several remarkable findings have been obtained using animal models. One of the most popular models, especially for research in infectious diseases, is the mouse. Regarding research in tuberculosis, the mouse has provided useful information about host and bacterial traits related to susceptibility to the infection. The effect of aging, sexual dimorphisms, the route of infection, genetic differences between mice lineages and unbalanced immunity scenarios upon Mycobacterium tuberculosis infection and tuberculosis development has helped, helps and will help biomedical researchers in the design of new tools for diagnosis, treatment and prevention of tuberculosis, despite various discrepancies and the lack of deep study in some areas of these traits.

TWEAK-Fn14 Axis Induces Calcium-Associated Autophagy and Cell Death To Control Mycobacterial Survival in Macrophages

Autophagy is a natural defense mechanism that protects the host against pathogens. We previously demonstrated that mycobacterial infection upregulated tumor necrosis factor-like weak inducer of apoptosis (TWEAK) to promote autophagy and mycobacterial autophagosome maturation through activation of AMP-activated protein kinase (AMPK). Fibroblast growth factor-inducible 14 (Fn14) is the receptor of TWEAK. But the role of Fn14 in mycobacterial infection remains elusive. Herein, we observed increased expression of Fn14 in peripheral blood mononuclear cells of active tuberculosis (TB) patients. Downregulation of cellular Fn14 enhanced mycobacterial survival in macrophages. Conversely, Fn14 overexpression inhibited mycobacterial growth, suggesting that Fn14 can inhibit mycobacterial infection. The in vitro results revealed that TWEAK-promoted mycobacterial phagosome maturation is Fn14-dependent. We demonstrated that TWEAK-Fn14 signaling promotes oxidative stress to enhance the expression of stromal interaction molecule 1 (STIM1) and its activation of the Ca2+ channel ORAI1. Elevated calcium influx stimulated the activation of CaMCCK2 (calcium/calmodulin-dependent protein kinase kinase 2) and its downstream effector AMPK, thus inducing autophagy in early infection. Persistently TWEAK-Fn14 signaling caused cell death in late infection by reducing mitochondrial membrane potential, leading to mitochondrial ROS accumulation, and activating cell death-associated proteins. Genetic Fn14 deficiency or TWEAK blockers decreased oxidative stress-induced calcium influx, thus suppressing autophagy and cell death in mycobacteria-infected macrophages, and resulting in elevated mycobacterial survival. We propose that the TWEAK-Fn14 axis and calcium influx could be manipulated for anti-TB therapeutic purposes. Our results offer a new molecular machinery to understand the association between the TWEAK-Fn14 axis, calcium influx, and mycobacterial infection. IMPORTANCE Tuberculosis remains a major cause of morbidity and mortality worldwide. We previously demonstrated a relationship between TWEAK and activation of the autophagic machinery, which promotes anti-mycobacterial immunity. The TWEAK-Fn14 axis is multi-functional and involved in the pathogenesis of many diseases, thus blockade of TWEAK-Fn14 axis has been considered as a potential therapeutic target. Here, we demonstrated that the TWEAK-Fn14 axis plays a novel role in anti-mycobacterial infection by regulating calcium-associated autophagy. Persistently, TWEAK-Fn14 signaling caused cell death in late infection by reducing mitochondrial membrane potential, leading to mitochondrial ROS accumulation, and activating cell death-associated proteins. TWEAK blocker or Fn14 deficiency could suppress oxidative stress and calcium-associated autophagy, resulting in elevated mycobacterial survival. We propose that the TWEAK-Fn14 axis and calcium influx could be manipulated for anti-TB therapeutic purposes. This study offers a new molecular machinery to understand the association between the TWEAK-Fn14 axis, calcium influx, and mycobacterial infection.

Immune evasion and provocation by Mycobacterium tuberculosis

Mycobacterium tuberculosis, the causative agent of tuberculosis, has infected humans for millennia. M. tuberculosis is well adapted to establish infection, persist in the face of the host immune response and be transmitted to uninfected individuals. Its ability to complete this infection cycle depends on it both evading and taking advantage of host immune responses. The outcome of M. tuberculosis infection is often a state of equilibrium characterized by immunological control and bacterial persistence. Recent data have highlighted the diverse cell populations that respond to M. tuberculosis infection and the dynamic changes in the cellular and intracellular niches of M. tuberculosis during the course of infection. M. tuberculosis possesses an arsenal of protein and lipid effectors that influence macrophage functions and inflammatory responses; however, our understanding of the role that specific bacterial virulence factors play in the context of diverse cellular reservoirs and distinct infection stages is limited. In this Review, we discuss immune evasion and provocation by M. tuberculosis during its infection cycle and describe how a more detailed molecular understanding is crucial to enable the development of novel host-directed therapies, disease biomarkers and effective vaccines.

Wnt5a regulates autophagy in Bacille Calmette-Guérin (BCG)-Infected pulmonary epithelial cells

Autophagy functions as a critical process that can suppress the proliferation of Mycobacterium tuberculosis (Mtb) within infected host cells. Wnt5a is a secreted protein that plays a range of physiological functions, activating several signaling pathways and thereby controlling cellular responses to particular stimuli. The importance of Wnt5a as a regulator of protection against Mtb infection, however, has yet to be fully characterized. Here, changes in murine pulmonary epithelial-like TC-1 cell morphology, autophagy, the Wnt/Ca²⁺ signaling pathway, and the mTOR autophagy pathway were analyzed following infection with the Mtb model pathogen Bacille Calmette-Guerin (BCG) in order to understand the regulatory role of Wnt5a in this context. These experiments revealed that Wnt5a was upregulated and autophagy was enhanced in TC-1 cells infected with BCG, and Wnt5a overexpression was found to drive BCG-induced autophagy in these cells upon infection, whereas the inhibition or knockdown of Wnt5a yielded the opposite effect. At the mechanistic level, Wnt5a was found to mediate non-canonical Wnt/Ca²⁺ signaling and thereby inhibit mTOR-dependent pathway activation, promoting autophagic induction within BCG-infected TC-1 cells. These data offer new insight regarding how Wnt5a influences Mtb-induced autophagy within pulmonary epithelial cells, providing a foundation for further research exploring the immunological control of this infection through the modulation of autophagy.

Different modalities of host cell death and their impact on Mycobacterium tuberculosis infection

Mycobacterium tuberculosis (Mtb) is the pathogen that causes tuberculosis (TB), a leading infectious disease of humans worldwide. One of the main histopathological hallmarks of TB is the formation of granulomas comprised of elaborately organized aggregates of immune cells containing the pathogen. Dissemination of Mtb from infected cells in the granulomas due to host and mycobacterial factors induces multiple cell death modalities in infected cells. Based on molecular mechanism, morphological characteristics, and signal dependency, there are two main categories of cell death: programmed and nonprogrammed. Programmed cell death (PCD), such as apoptosis and autophagy, is associated with a protective response to Mtb by keeping the bacteria encased within dead macrophages that can be readily phagocytosed by arriving in uninfected or neighboring cells. In contrast, non-PCD necrotic cell death favors the pathogen, resulting in bacterial release into the extracellular environment. Multiple types of cell death in the PCD category, including pyroptosis, necroptosis, ferroptosis, ETosis, parthanatos, and PANoptosis, may be involved in Mtb infection. Since PCD pathways are essential for host immunity to Mtb, therapeutic compounds targeting cell death signaling pathways have been experimentally tested for TB treatment. This review summarizes different modalities of Mtb-mediated host cell deaths, the molecular mechanisms underpinning host cell death during Mtb infection, and its potential implications for host immunity. In addition, targeting host cell death pathways as potential therapeutic and preventive approaches against Mtb infection is also discussed.

microRNAs associated with the pathogenesis and their role in regulating various signaling pathways during Mycobacterium tuberculosis infection

Despite more than a decade of active study, tuberculosis (TB) remains a serious health concern across the world, and it is still the biggest cause of mortality in the human population. Pathogenic bacteria recognize host-induced responses and adapt to those hostile circumstances. This high level of adaptability necessitates a strong regulation of bacterial metabolic characteristics. Furthermore, the immune reponse of the host virulence factors such as host invasion, colonization, and survival must be properly coordinated by the pathogen. This can only be accomplished by close synchronization of gene expression. Understanding the molecular characteristics of mycobacterial pathogenesis in order to discover therapies that prevent or resolve illness relies on the bacterial capacity to adjust its metabolism and replication in response to various environmental cues as necessary. An extensive literature details the transcriptional alterations of host in response to in vitro environmental stressors, macrophage infection, and human illness. Various studies have recently revealed the finding of several microRNAs (miRNAs) that are believed to play an important role in the regulatory networks responsible for adaptability and virulence in Mycobacterium tuberculosis. We highlighted the growing data on the existence and quantity of several forms of miRNAs in the pathogenesis of M. tuberculosis, considered their possible relevance to disease etiology, and discussed how the miRNA-based signaling pathways regulate bacterial virulence factors.

MicroRNAs as immune regulators and biomarkers in tuberculosis

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (Mtb), is one of the most lethal infectious disease worldwide, and it greatly affects human health. Some diagnostic and therapeutic methods are available to effectively prevent and treat TB; however, only a few systematic studies have described the roles of microRNAs (miRNAs) in TB. Combining multiple clinical datasets and previous studies on Mtb and miRNAs, we state that pathogens can exploit interactions between miRNAs and other biomolecules to avoid host mechanisms of immune-mediated clearance and survive in host cells for a long time. During the interaction between Mtb and host cells, miRNA expression levels are altered, resulting in the changes in the miRNA-mediated regulation of host cell metabolism, inflammatory responses, apoptosis, and autophagy. In addition, differential miRNA expression can be used to distinguish healthy individuals, patients with TB, and patients with latent TB. This review summarizes the roles of miRNAs in immune regulation and their application as biomarkers in TB. These findings could provide new opportunities for the diagnosis and treatment of TB.

Immune regulation and emerging roles of noncoding RNAs in Mycobacterium tuberculosis infection

Tuberculosis, caused by Mycobacterium tuberculosis, engenders an onerous burden on public hygiene. Congenital and adaptive immunity in the human body act as robust defenses against the pathogens. However, in coevolution with humans, this microbe has gained multiple lines of mechanisms to circumvent the immune response to sustain its intracellular persistence and long-term survival inside a host. Moreover, emerging evidence has revealed that this stealthy bacterium can alter the expression of demic noncoding RNAs (ncRNAs), leading to dysregulated biological processes subsequently, which may be the rationale behind the pathogenesis of tuberculosis. Meanwhile, the differential accumulation in clinical samples endows them with the capacity to be indicators in the time of tuberculosis suffering. In this article, we reviewed the nearest insights into the impact of ncRNAs during Mycobacterium tuberculosis infection as realized via immune response modulation and their potential as biomarkers for the diagnosis, drug resistance identification, treatment evaluation, and adverse drug reaction prediction of tuberculosis, aiming to inspire novel and precise therapy development to combat this pathogen in the future.

MiR-27a-3p and miR-30b-5p inhibited-vitamin D receptor involved in the progression of tuberculosis

Background

MicroRNAs (miRNAs) play a vital role in tuberculosis (TB). Vitamin D receptor (VDR), an miRNA target gene, and its ligand, vitamin D₃ (VitD₃), have been reported to exert protective effects against TB. However, whether miRNAs can affect the progression of TB by targeting VDR has not been reported.

Materials and methods

Research subjects were selected according to defined inclusion criteria. A clinical database of 360 samples was established, including the subjects’ demographic information, miRNA expression profiles and cellular experimental results. Two candidate miRNAs, miR-27a-3p, and miR-30b-5p, were identified by a high-throughput sequencing screen and validated by qRT–PCR assays. Univariate and multivariate statistical analyses were performed. VDR and NF-kB p65 protein levels were detected by Western blot assays. Proinflammatory cytokine expression levels were detected by enzyme-linked immunosorbent assay (ELISA). Luciferase assays and fluorescence-activated cell sorting (FACS) were further applied to elucidate the detailed mechanisms.

Results

Differential miRNA expression profiles were obtained, and miR-27a-3p and miR-30b-5p were highly expressed in patients with TB. These results showed that the two miRNAs were able to induce M1 macrophage differentiation and inhibit M2 macrophage differentiation. Further experiments showed that the two miRNAs decreased the VDR protein level and increased proinflammatory cytokine secretion by macrophages. Mechanistically, the miRNAs targeted the 3′ untranslated region (3′UTR) of the VDR mRNA and thereby downregulated VDR protein levels by post-transcriptional regulation. Then, due to the reduction in VDR protein levels, the NF-kB inflammatory cytokine signaling pathway was activated, thus promoting the progression of TB.

Conclusion

Our study not only identified differentially expressed miRNAs between the TB and control groups but also revealed that miR-27a-3p and miR-30b-5p regulate proinflammatory cytokine secretion and macrophage differentiation through VDR in macrophages. Thus, these two miRNAs influence the progression of TB.

Ginsenoside Rg1 Inhibits STAT3 Expression by miR-15b-5p to Attenuate Lung Injury in Mice with Type 2 Diabetes Mellitus-Associated Pulmonary Tuberculosis

Type 2 diabetes mellitus (T2DM) has been regarded as a critical risk factor for pulmonary tuberculosis (PTB). Ginsenoside Rg1 has been identified as a potential therapeutic agent for T2DM by suppressing the inflammatory response. However, the effect of Rg1 on T2DM-associated PTB has not been reported. In this study, we aimed to explore the function of Rg1 in the regulation of T2DM-associated PTB. We established a T2DM-associated PTB mouse model and found that the fibrosis of lung tissues was inhibited by Rg1 in T2DM-associated PTB mice. The lung injury of T2DM-associated PTB mice was repressed by Rg1. Moreover, the levels of IL-6, TNF-α, and IL-1β in the lung tissues and serum were decreased by Rg1 in T2DM-associated PTB mice. The treatment with Rg1 inhibited the levels of free fatty acid and enhanced the expression of miR-15b-5p in lung tissues of T2DM-associated PTB mice. MiR-15b-5p targeted and inhibited the STAT3 expression. The expression of STAT3 was downregulated by Rg1, while the inhibition of miR-15b-5p reversed the downregulation. The expression of miR-15b-5p was reduced, but the expression of STAT3 was upregulated in the lung tissues of T2DM-associated PTB mice. We validated that miR-15b-5p attenuated inflammation and lung injury in the T2DM-associated PTB mouse model. The overexpression of STAT3 or the suppression of miR-15b-5p restored lung fibrosis and injury inhibited by Rg1 in T2DM-associated PTB mice. Meanwhile, the Rg1-repressed levels of IL-6, TNF-α, and IL-1β were enhanced by the overexpression of STAT3 or the suppression of miR-15b-5p. In addition, the levels of free fatty acid repressed by Rg1 were reversed by STAT3 overexpression and miR-15b-5p inhibition. Thus, we conclude that ginsenoside Rg1 inhibits the STAT3 expression by miR-15b-5p to attenuate lung injury in mice with type 2 diabetes mellitus-associated pulmonary tuberculosis.

MicroRNA-31 mediated by interferon regulatory factor 7 signaling facilitates control of Mycobacterium tuberculosis infection

Tuberculosis (TB) induced by Mycobacterium tuberculosis (M. tuberculosis) infection remains a global most deadly infectious disease. While development of more effective TB vaccines and therapeutics relies on identifications of true biomarkers designating an immune protection against M. tuberculosis infection, exact protective immune components against M. tuberculosis infection remain largely unidentified. We previously found that severe TB induced remarkable up-regulation of interferon regulatory factor 7 (IRF7) and IRF7-related gene signatures, implicating that some unknown downstream molecules in IRF7 signaling cascades may determine the M. tuberculosis infection outcomes and serve as a protective immune component against M. tuberculosis infection. Indeed, here, we observe that genetic ablation of IRF7 leads to more severe lung pathology, increased M. tuberculosis burdens, impaired differentiation of effector/memory T subsets, and extensively elevated expression of pro-inflammatory cytokines in lungs. Importantly, IRF7 is vital for sustaining expression of PD-1/PD-L1 and PD-1/PD-L1-modulated miRNA-31. Moreover, interventions of miRNA-31 expressions via administration of miRNA-31 agomir reduces lung pathology and bacilli burdens via inducing up-regulation of gene sets involved in biological processes of defense response or cellular and chemical homeostasis in lungs. Thus, this study uncovers previously unrecognized importance and mechanisms of IRF7-mediated miRNA-31 as a protective immune component against M. tuberculosis infection.

p50-associated Cyclooxygenase-2 Extragenic RNA (PACER) and Long Non-coding RNA 13 (LNC13) as potential biomarkers for monitoring tuberculosis treatment

Gaps in early and accurate diagnosis, effective drug control, and treatment monitoring are hindering the global eradication effort of tuberculosis. This infectious disease has become the deadliest worldwide before the outbreak of Covid-19. The search for new molecular biomarkers of tuberculosis will help to reverse this trend. Long non-coding RNAs (lncRNAs) have emerged as important regulators of the host immune response to infection, hence their link with the etiology and diagnosis of tuberculosis has attracted some attention from the research community. However, very little is known about their potential for the monitoring of tuberculosis treatment. This study aimed at assessing the potential of two lncRNAs: p50-associated Cyclooxygenase-2 Extragenic RNA (PACER) and Long Non-coding RNA 13 (LNC13) in the monitoring of tuberculosis treatment. This was a cross-sectional study carried out in Douala, Cameroon from December 2020 to August 2021. A quantitative real-time polymerase chain reaction followed by Cq analysis using the Livak method were performed to measure the relative expression levels of PACER and LNC13 in whole blood of healthy controls, patients with active pulmonary tuberculosis at the initiation of treatment, after two, five, and six months into treatment. Receiver Operating Characteristic curves analysis was used to assess the ability of targeted lncRNAs to discriminate among those groups. The study showed that the lncRNAs PACER and LNC13 were significantly upregulated in patients with active pulmonary tuberculosis at the initiation of treatment than in healthy controls. The expression levels of the two lncRNAs were significantly downregulated in patients during the treatment as compared to the active pulmonary tuberculosis patients. However, the expression levels of the lncRNAs PACER and LNC13 in whole blood of patients after six months of treatment were similar to those in healthy controls. Similarly, lncRNAs PACER and LNC13 showed very good performance in distinguishing between active tuberculosis patients and healthy controls as well as in differentiating between newly diagnosed active tuberculosis patients and those under treatment. Interestingly, those lncRNAs could not discriminate healthy controls from patients after six months of treatment. The lncRNAs PACER and LNC13 are therefore potential biomarkers for the monitoring of tuberculosis treatment.

Role of miR-451 in mediating cadmium induced head kidney injury in common carp via targeting cacna1ab through autophagy pathways

Cadmium (Cd) is a common environmental pollutant, which leads to Cd residue in aquatic animals. The Cd in aquatic animals will be enriched into the human body through the food chain and seriously harm human health. The research aims to investigate the molecular mechanism of Cd poisoning in common carps. Our previous studies have confirmed that 23 differentially expressed miRNAs were potential biomarkers for Cd exposure in common carp head kidney lymphocytes. Herein, based on the prediction of the website and previous studies, miR-451 and cacna1ab were selected and their targeting relationship was verified again by dual-luciferase. Subsequently, we established the miR-451 overexpression/knockdown models and miR-451 inhibitor, cacna1ab co-knockdown models in common carp head kidney lymphocytes respectively. Immunofluorescence staining, MDC staining, calcium staining, qRT-PCR (Quantitative Real-time PCR) and western blot were used to detect the levels of autophagy. Our results demonstrated that Cd significantly decreased the expression of miR-451, miR-451 suppression thereby induced increased cacna1ab and the expression of ATG5, LC3-I, LC3-II and Beclin 1, while significantly inhibiting the expression of mTOR, P62 and Bcl-2, which indicated that autophagy was triggered. Moreover, the miR-451 knockdown group activated the expression of autophagy related factors as well as the Cd group. However, cacna1ab knockdown can reduce autophagy activation induced by miR-451 knockdown. Our results indicated that Cd induced autophagy in head kidney lymphocytes through the inhibition of miR-451 and the excitation of cacna1ab.

Overexpression of VPS11 antagonizes the promoting effect of miR-542-3p on Mycobacterium tuberculosis survival in macrophages by regulating autophagy

Impaired autophagy is an important cause of Mycobacterium tuberculosis survival in macrophages. VPS11 is an important regulator of autophagy; decreased VPS11 expression has been observed in macrophages after tuberculosis (TB) infection. Gene ontology data revealed that various miRNAs (for example, miR-542-3p) were upregulated in macrophages upon TB infection; thus, these miRNAs were likely to reduce VPS11 expression. In this study, both TB patients and healthy subjects were enrolled, and the levels of VPS11 and some miRNAs in their blood macrophages were measured. Moreover, various macrophages were cultured and infected with M. tuberculosis. Luciferase reporter, RNA pulldown, and RNA immunoprecipitation assays were performed to determine the regulatory effect of miR-542-3p on VPS11 expression. Results showed that VPS11 expression was downregulated, whereas miR-542-3p expression was upregulated in blood macrophages after TB infection. TB infection reduced VPS11 levels in two human macrophages in vitro, but not in mouse macrophages. This might be because the seed sequence exists in the VPS11 3' untranslated region in humans, but is absent in mice and rats. miR-542-3p promoted M. tuberculosis survival in human macrophages, but VPS11 overexpression antagonized the promoting effect of miR-542-3p. Further, VPS11 was confirmed as a target of miR-542-3p. Overexpression of VPS11 or depletion of miR-542-3p promoted autophagy, which was suppressed upon TB infection. In summary, VPS11 overexpression antagonized the promoting effect of miR-542-3p on M. tuberculosis survival in macrophages by regulating autophagy.

MiR-25 blunts autophagy and promotes the survival of Mycobacterium tuberculosis by regulating NPC1

Mycobacterium tuberculosis (Mtb) evades host clearance by inhibiting autophagy. MicroRNA-25 (miR-25) expression was significantly up-regulated in the lung tissues of mice infected with Bacillus Calmette-Guerin (BCG) and macrophages infected with Mtb or BCG, especially in the early stages of infection. MiR-25 can significantly increase the survival of Mtb and BCG in macrophages. We validated that miR-25 targets the NPC1 protein located on the lysosomal membrane, resulting in damage to lysosomal function, thereby inhibiting autophagolysosome formation and promoting the survival of Mtb and BCG. Consistently, mice lacking miR-25 exhibited more resistant to BCG infection. In addition, we found that Rv1759c induces the expression of miR-25 through NFKB inhibitor zeta (NFKBIZ). This study demonstrates that the role of miR-25 during Mtb infection contributes to a better understanding of the pathogenesis of tuberculosis (TB).

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Mtb up-modulates miR-25 expression especially in the early stage of infection

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miR-25 targeting NPC1 impairs autophagic flux in macrophages

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Mice lacking miR-25 exhibits more resistant to BCG infection

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Rv1759c regulates miR-25 expression and Mtb survival via NFKBIZ

Negative pressure promotes macrophage M1 polarization after Mycobacterium tuberculosis infection via the lncRNA XIST/microRNA-125b-5p/A20/NF-κB axis

Experiments have demonstrated the regulation of long noncoding RNA (lncRNA) in tuberculosis (TB), and negative pressure treatment has been associated with the alleviation of TB. Here, we investigated the interaction of negative pressure and the lncRNA X-inactive specific transcript (XIST) in modulating Mycobacterium tuberculosis (MTB) infection. Initially, we established an in vitro cell model of MTB infection and an in vivo mouse model of MTB infection, followed by treatment with negative pressure. Then, we examined the expression of XIST, followed by analysis of the downstream miRNA of XIST. XIST was overexpressed or underexpressed through cell transfection to examine its effects on macrophage polarization via the miR-125b-5p/A2 axis. The MTB models were characterized by upregulated XIST and downregulated miR-125b-5p. XIST bound to miR-125b-5p, leading to its downregulation, and thus causing higher MTB survival in an ESAT-6-dependent manner. Additionally, negative pressure treatment decreased MTB-driven XIST expression through downregulation of A20 (an NF-κB repressor) via miR-125b-5 expression, promoting the M1 polarization program in macrophages through activation of the NF-κB pathway. In summary, negative pressure treatment after MTB infection can promote the polarization of macrophages to the proinflammatory M1 phenotype by regulating the XIST/miR-125b-5p/A20/NF-κB axis.