Search Results (153)

The global burden of tuberculosis (TB), exacerbated by the rise of drug-resistant Mycobacterium tuberculosis (M. tuberculosis), underscores the need for alternative intervention strategies. One promising approach is to block the infection at its earliest stage—bacterial adhesion to host cells—thereby preventing colonization and transmission without exerting selective pressure. Adhesins, surface-exposed molecules mediating this critical interaction, have therefore emerged as attractive targets for early prevention. This review outlines the infection process driven by bacterial adhesion and describes the architecture of the M. tuberculosis outer envelope, emphasizing components that contribute to host interaction. We comprehensively summarize both non-protein and protein adhesins, detailing their host receptors, biological roles, and experimental evidence. Recent progress in the computational prediction of adhesins, particularly neural network-based tools like SPAAN, is also discussed, highlighting its potential to accelerate adhesin discovery. Additionally, we present a detailed, generalized workflow for predicting M. tuberculosis adhesins, which synthesizes current approaches and provides a comprehensive framework for future studies. Targeting bacterial adhesion presents a therapeutic strategy that interferes with the early stages of infection while minimizing the risk of developing drug resistance. Consequently, anti-adhesion strategies may serve as valuable complements to conventional therapies and support the development of next-generation TB vaccines and treatments. Full article

Worldwide, several million people are infected with mycobacteria such as Mycobacterium tuberculosis (M. tb) or non-tuberculous mycobacteria (NTM). In 2023, 10.8 million cases and 1.25 million deaths due to M. tb were recorded. In Europe and North America, the emergence of NTM is tending to outstrip that of M. tb. Among pulmonary NTM, Mycobacterium avium complex (MAC) is the most common, accounting for 80% of NTM infections. First-line treatment requires the combination of at least three antibiotics over a long period and with different mechanisms of action to limit cross-resistance. The challenge is to discover more effective new anti-MAC molecules to reduce the duration of treatment and to overcome resistant strains. The aim of this review is to present an overview of the challenges posed by MAC infection such as side effects, reinfections and resistance mechanisms. The latest therapeutic options such as the optimized combination therapy, drug repurposing and the development of new formulations, as well as new anti-MAC compounds currently in (pre)clinical trials will also be discussed. Full article

Background and Objectives: Tuberculosis (TB) is one of the most common infectious diseases in developing countries. The resistance of the causative agent, Mycobacterium tuberculosis, to two or more first-line anti-TB drugs results in multidrug-resistant (MDR) TB, posing a serious challenge to the control of TB worldwide. This study was designed to determine the changes in drug resistance over time in TB strains isolated from patients in all departments of Uludağ University Hospital in western Türkiye. Materials and Methods: We retrospectively analyzed 104,598 clinical samples sent to our laboratory for the investigation of the presence of TB between 1996 and 2023. BACTEC 460 TB, BACTEC MGIT 960 culture systems and Löwenstein–Jensen medium were used for the culture of these samples. The susceptibility of M. tuberculosis complex strains grown in culture to isoniazid (INH) (0.1 μg/mL), rifampicin (RIF) (1.0 μg/mL), ethambutol (ETB) (5.0 μg/mL) and streptomycin (SM) (1.0 μg/mL) antibiotics was studied according to the manufacturer’s recommendation. Results: Out of 104,598 patient samples, 2752 (2.6%) were culture-positive, and the susceptibility test results of 1869 of these were analyzed. Of the isolates, 358 (19.2%) were found to be resistant to at least one first-line drug, i.e., INH, RIF, ETB, or SM. In addition, 2.9% were resistant to two or more first-line drugs. Conclusions: Drug susceptibility testing is essential to ensure the optimal treatment and control of drug-resistant TB strains. This study highlights the value of ongoing efforts to control tuberculosis drug resistance in the fight against this disease. Full article

Background: The appearance of new clinical manifestations (for example, subcutaneous or skin abscesses) during anti-tuberculosis treatment is generally indicative of therapeutic failure. The cause of therapeutic failure may be the presence of a drug-resistant Mycobacterium infection or to the failure to achieve a sufficient concentration of the drugs in the bloodstream. Case report: Here, we report the case of a 25-year-old man suffering from tuberculosis infection with lymph-node and pulmonary involvement and an atypical response to specific therapy. Two weeks after starting four-drug antitubercular treatment, the patient began to experience fever, pain and functional impotence in the left foot and ankle, with subsequent evidence of ankle and tarsal osteomyelitis. Four weeks after starting treatment, the patient presented with several widespread, painful subcutaneous abscesses on the trunk, back and right lower limb. Drainage was performed from the ankle and from one of the abscesses, and polymerase chain reaction (PCR) showed a positive result for M. tuberculosis in both samples, with the absence of resistance to drugs. Anti-tubercular medications were continued, with resolution of the pulmonary and bone involvement but with persistence of subcutaneous abscesses, although subsequent drainages showed the absence of mycobacterium tuberculosis. Conclusions: We describe an unusual presentation of paradoxical reaction in the form of osteomyelitis and subcutaneous abscesses in an immunocompetent TB patient, and we reported other similar cases of paradoxical reactions described in the literature in the last ten years, which demonstrate the importance of considering paradoxical reactions in patients who present with new or worsening signs and symptoms after starting tuberculosis treatment. Full article

The long regimen of drug therapy, the emergence of drug-resistance (DR), and infections with non-tuberculous mycobacteria (NTMs) are alarming challenges in controlling tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M.tb), necessitating the pursuit of new, broad-spectrum anti-mycobacterials. With more than two-thirds of the clinically useful antibiotics originating from the bacterial phylum Actinomycetota, and their enormous diversity in India, we explored atypical environments for new bacterial strains with potential anti-M.tb activity. In this study, we the examined the secondary metabolites of soil and endophytic bacterial isolates from the wetland niches of Manipur, India, and determined their anti-mycobacterial properties using viability assays. The ethyl acetate culture filtrate extracts of one of the isolates, named Streptomyces sp. SbAr007, showed broad-spectrum anti-mycobacterial activity against laboratory M.tb strains H37Ra and H37Rv, a clinical drug-resistant M.tb and non-tuberculous mycobacteria (NTM). The isolate was characterized for its phenotype and genetic identity, which indicated its closeness to Streptomyces samsunensis, Streptomyces malaysiensis, and Streptomyces solisilvae. Further, macrophage infection assays showed that the extracts could effectively control the intracellular mycobacterial growth but had negligible cytotoxicity to PBMCs from healthy donors. LC-MS identified an unusual combination of antibiotics in these culture filtrate extracts, which can be further explored for specific active molecules or as a formulation against DR-TB. Full article

Traumatic brain injury (TBI) has a complex and multifactorial pathology and is a major cause of death and disability for humans. Immediately after TBI, astrocytes and microglia react with complex morphological and functional changes known as reactive gliosis to form a glial scar in the area immediately adjacent to the lesion, which is the major barrier to neuronal regeneration. The flavonoid agathisflavone (bis-apigenin), present in Poincianella pyramidalis leaves, has been shown to have neuroprotective, neurogenic, and anti-inflammatory effects, demonstrated in vitro models of glutamate-induced toxicity, neuroinflammation, and demyelination. In this study, we evaluated the effect and mechanisms of agathisflavone in neuronal integrity and in the modulation of gliosis in an ex vivo model of TBI. For this, microdissections from the encephalon of Wistar rats (P6-8) were prepared and subjected to mechanical injury (MI) and treated or not with daily agathisflavone (5 μM) for 3 days. Astrocyte reactivity was investigated by measuring mRNA and expression of GFAP protein in the lesioned area by immunofluorescence and Western blot. The proportion of microglia was determined by immunofluorescence for Iba-1; mRNA expression for inflammasome NRPL3 and interleukin-1 beta (IL-1β) was determined by RT-qPCR. It was observed that lesions in the cortical tissue induced astrocytes overexpressing GFAP in the typical glial scar formed and that agathisflavone modulated GFAP expression at the transcriptional and post-transcriptional levels, which was associated with a reduction of the glial scar. MI induced an increase in the proportion of microglia (Iba-1+), which was not observed in agathisflavone-treated cultures. Moreover, the flavonoid modulated negatively both the NRLP3 and IL-1β mRNA expression that was increased in the lesioned area of the tissue. These findings support the regulatory properties of agathisflavone in the control of the inflammatory response in glial cells, which can impact neuroprotection and should be considered for future studies for TB and other pathological conditions of the central nervous system. Full article

Background/Objectives: Tuberculosis (TB) is one of the leading infectious causes of death worldwide, highlighting the importance of identifying new anti-TB agents. In previous research, our team identified antimycobacterial activity in Kielmeyera membranacea leaf extract; therefore, this study aims to conduct further exploration of its potential. Methods: Classical chromatography was applied for fractionation and spectrometric techniques were utilized for chemical characterization. For in vitro tests, samples were assessed against Mycobacterium tuberculosis and Mycobacterium marinum. The toxicity and efficacy of active samples were evaluated in vivo using different zebrafish models. Chemogenomics studies were applied to predict the isolated active compound’s potential mode of action. Results: We performed fractionation of K. membranacea ethanolic extract (EE) and then its dichloromethane fraction (DCM), and the biflavonoid podocarpusflavone A (PCFA) was isolated and identified as a promising active compound. The EE and PCFA were found to be non-toxic to zebrafish larvae and were able to inhibit M. tuberculosis growth extracellularly. Additionally, PCFA demonstrated antimycobacterial activity within infected macrophages, especially when combined with isoniazid. In addition, the EE, DCM, and PCFA have shown the ability to inhibit M. marinum’s growth during in vivo zebrafish larvae yolk infection. Notably, PCFA also effectively countered systemic infection established through the caudal vein, showing a similar inhibitory activity profile to rifampicin, both at 32 µM. A reduction in the transcriptional levels of pro-inflammatory cytokines confirmed the infection resolution. The protein tyrosine phosphatase B (PtpB) of M. tuberculosis, which inhibits the macrophage immune response, was predicted as a theoretical target of PCFA. This finding is in agreement with the higher activity observed for PCFA intracellularly and in vivo on zebrafish, compared with the direct action in M. tuberculosis. Conclusions: Here, we describe the discovery of PCFA as an intracellular inhibitor of M. tuberculosis and provide evidence of its in vivo efficacy and safety, encouraging its further development as a combination drug in novel therapeutic regimens for TB. Full article

Mentha longifolia (L.) L., also known as wild mint, is a perennial herbaceous plant that belongs to the Lamiaceae family. This study aimed to investigate the effects of essential oil of M. longifolia (MLEO) on oxidative stress and inflammatory responses in the liver and kidneys in the context of drug-induced liver injury caused by the anti-TB drugs rifampicin, isoniazid, and pyrazinamide (INH-RIF-PZA). The chemical composition of MLEO was characterized using GC/MS analysis, which revealed the presence of pulegone, trans-p-menthan-3-one, piperitenone, and β-caryophyllene as its major volatile constituents. An INH/RIF/PZA mixture was administered to Wistar rats for 30 days, and silymarin was administered as a standard drug. MLEO was administered p.o. at doses of 50 mg and 100 mg/kg b.w. Both doses of the MLEO therapy effectively regulated all biochemical indicators of hepatic impairment and reduced the damage caused by the INH/RIF/PZA mixture. It may be deduced that MLEO has the ability to protect organs against INH/RIF/PZA-induced damage and could potentially be a valuable natural remedy for treating anti-TB-induced liver and kidney injuries. Full article

In this study, we aimed to assess the activity of the essential oils from four Bulgarian oil-bearing roses Rosa damascena Mill., R. alba L., R. centifolia L., and R. gallica L., on the reference strain Mycobacterium tuberculosis H37Rv and clinical M. tuberculosis strains of the Beijing and Latin-American Mediterraneum genotypes. The chemical composition of the essential oils was determined by gas chromatography (GC-FID/MS). Minimal inhibitory concentrations (MIC) were determined using the resazurin method. R. alba oil showed the highest inhibitory activity when tested on all strains of different phylogenetic origins with MIC in the range of 0.16–0.31 mg/mL, while R. gallica oil was the least active (MIC 0.62–1.25 mg/mL). The obtained results show heterogeneity of rose oil action on different mycobacterial strains and we hypothesize that the combined level of geraniol and nerol is a key factor that underlies the antimycobacterial action of the rose oils. Strain Beijing 396 was relatively more susceptible to the rose oils probably due to multiple and likely deleterious mutations in its efflux pump genes. Two clinical MDR strains have likely developed during their previous adaptation to anti-TB drugs certain drug tolerance mechanisms that also permitted them to demonstrate intrinsic tolerance to the essential oils. Further research should investigate a possible synergistic action of the new-generation anti-TB drugs and the most promising rose oil extracts on the large panel of different strains. Full article

Ursolic acid (UA) and oleanolic acid (OA) are hydrophobic triterpenoid isomers with demonstrated anti-mycobacterial (Mtb) and immune-regulatory properties, although their poor solubility limits clinical use. We report the development of solid lipid microparticles (SLMs) as delivery vehicles for UA and OA and evaluate their anti-Mtb efficacy in vitro and in vivo, as well as their acute toxicity. SLMs measured 0.7–0.89 µM in size, with complete in vitro release of OA and UA at 40 and 32 h, respectively. The minimum inhibitory concentration (MIC) of SLMs loaded with OA and UA was 40 µg/mL SLMs + 20 µg/mL OA + 20 µg/mL UA for drug-sensitive Mtb and 80 µg/mL SLMs + 40 µg/mL OA + 40 µg/mL UA for multidrug-resistant (MDR) Mtb. These SLMs showed an efficient reduction in Mtb burden in infected alveolar macrophages. In a murine model of late-stage progressive MDR-TB, aerosolized delivery of SLMs containing OA and UA via a metered-dose inhaler significantly reduced pulmonary bacterial loads and extended survival. In vivo, acute toxicity studies revealed no mortality or signs of toxicity. These findings demonstrate that SLMs are an optimal delivery system for terpenoids, providing potent in vitro and in vivo anti-TB activity with an excellent safety profile. Full article

Tuberculosis (TB) is a global infectious threat, and the emergence of multidrug-resistant TB has become a major challenge in eradicating the disease that requires the discovery of new treatment strategies. This study aimed to elucidate the immune infiltration and molecular regulatory network of T cell-interacting activating receptors on myeloid cell 1 (TARM1)-related genes based on a bioinformatics analysis. The GSE114911 dataset was obtained from the Gene Expression Omnibus (GEO) and screened to identify 17 TARM1-related differentially expressed genes (TRDEGs). Genes interacting with the TRDEGs were analyzed using a Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. A gene set enrichment analysis (GSEA) was used to identify the biological pathways significantly associated with a Mycobacterium tuberculosis (Mtb) infection. The key genes were obtained based on Cytoscape’s cytoHubba plug-in. Furthermore, protein–protein interaction (PPI) networks were analyzed through STRING, while mRNA–RNA-binding protein (RBP) and mRNA–transcription factor (TF) interaction networks were developed utilizing the StarBase v3.0 and ChIPBase databases. In addition, the diagnostic significance of key genes was evaluated via receiver operating characteristic (ROC) curves, and the immune infiltration was analyzed using an ssGSEA and MCPCounter. The key genes identified in the GSE114911 dataset were confirmed in an independent GSE139825 dataset. A total of seventeen TRDEGs and eight key genes were obtained in a differential expression analysis using the cytoHubba plug-in. Through the GO and KEGG analysis, it was found that these were involved in the NF-κB, PI3K/Akt, MAPK, and other pathways related to inflammation and energy metabolism. Furthermore, the ssGSEA and MCPCounter analysis revealed a significant rise in activated T cells and T helper cells within the Mtb infection group, which were markedly associated with these key genes. This implies their potential significance in the anti-Mtb response. In summary, our results show that TRDEGs are linked to inflammation, energy metabolism, and immune cells, offering fresh insights into the mechanisms underlying TB pathogenesis and supporting further investigation into the possible molecular roles of TARM1 in TB, as well as assisting in the identification of prospective diagnostic biomarkers. Full article

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. Full article

The zoonotic transmission of hepatitis E virus (HEV) genotypes 3 (HEV-3) and 4 (HEV-4), and rabbit HEV (HEV-3ra) has been documented. Vaccination against HEV infection depends on the capsid (open reading frame 2, ORF2) protein, which is highly immunogenic and elicits effective virus-neutralizing antibodies. Escherichia coli (E. coli) is utilized as an effective system for producing HEV-like particles (VLPs). However, research on the production of ORF2 proteins from these HEV genotypes in E. coli to form VLPs has been modest. In this study, we constructed 21 recombinant plasmids expressing various N-terminally and C-terminally truncated HEV ORF2 proteins for HEV-3, HEV-3ra, and HEV-4 in E. coli. We successfully obtained nine HEV-3, two HEV-3ra, and ten HEV-4 ORF2 proteins, which were primarily localized in inclusion bodies. These proteins were solubilized in 4 M urea, filtered, and subjected to gel filtration. Results revealed that six HEV-3, one HEV-3ra, and two HEV-4 truncated proteins could assemble into VLPs. The purified VLPs displayed molecular weights ranging from 27.1 to 63.4 kDa and demonstrated high purity (74.7–95.3%), as assessed by bioanalyzer, with yields of 13.9–89.6 mg per 100 mL of TB medium. Immunoelectron microscopy confirmed the origin of these VLPs from HEV ORF2. Antigenicity testing indicated that these VLPs possess characteristic HEV antigenicity. Evaluation of immunogenicity in Balb/cAJcl mice revealed robust anti-HEV IgG responses, highlighting the potential of these VLPs as immunogens. These findings suggest that the generated HEV VLPs of different genotypes could serve as valuable tools for HEV research and vaccine development. Full article

Since their conception with the smallpox vaccine, vaccines used worldwide have mitigated multiple pandemics, including the recent COVID-19 outbreak. Insightful studies have uncovered the complexities of different functional networks of CD4 T cells (T helper 1 (Th1); Th2, Th17) and CD8 T cells (T cytotoxic; Tc), as well as B cell (B^IgM, B^IgG, B^IgA and B^IgE) subsets, during the response to vaccination. Both T and B cell subsets form central, peripheral, and tissue-resident subsets during vaccination. It has also become apparent that each vaccination forms a network of T regulatory subsets, namely CD4+ CD25+ Foxp3⁺ T regulatory (Treg) cells and interleukin-10 (IL-10)-producing CD4+ Foxp3⁻ T regulatory 1 (Tr1), as well as many others, which shape the quality/quantity of vaccine-specific IgM, IgG, and IgA antibody production. These components are especially critical for immunocompromised patients, such as older individuals and allograft recipients, as their vaccination may be ineffective or less effective. This review focuses on considering how the pre- and post-vaccination Treg/Tr1 levels influence the vaccination efficacy. Experimental and clinical work has revealed that Treg/Tr1 involvement evokes different immune mechanisms in diminishing vaccine-induced cellular/humoral responses. Alternative steps may be considered to improve the vaccination response, such as increasing the dose, changing the delivery route, and/or repeated booster doses of vaccines. Vaccination may be combined with anti-CD25 (IL-2Rα chain) or anti-programmed cell death protein 1 (PD-1) monoclonal antibodies (mAb) to decrease the Tregs and boost the T/B cell immune response. All of these data and strategies for immunizations are presented and discussed, aiming to improve the efficacy of vaccination in humans and especially in immunocompromised and older individuals, as well as organ transplant patients. Full article

Psoriasis, an immune-mediated inflammatory skin disorder, seriously affects the quality of life of nearly four percent of the world population. Euphorbia helioscopia L. is the monarch constituent of Chinese ZeQi powder preparation for psoriasis, so it is necessary to illustrate its active ingredients. Thus, twenty-three diterpenoids, including seven new ones, were isolated from the whole herb of E. helioscopia L. Compounds 1 and 2, each featuring a 2,3-dicarboxylic functionality, are the first examples in the ent-2,3-sceo-atisane or the ent-2,3-sceo-abietane family. Extensive spectroscopic analysis (1D, 2D NMR, and HRMS data) and computational methods were used to confirm their structures and absolute configurations. According to the previous study and NMR data from the jatropha diterpenes obtained in this study, some efficient ¹H NMR spectroscopic rules for assigning the relative configurations of 3α-benzyloxy-jatroph-11E-ene and 7,8-seco-3α-benzyloxy-jatropha-11E-ene were summarized. Moreover, the hyperproliferation of T cells and keratinocytes is considered a key pathophysiology of psoriasis. Anti-proliferative activities against induced T/B lymphocytes and HaCaT cells were tested, and IC₅₀ values of some compounds ranged from 6.7 to 31.5 μM. Compounds 7 and 11 reduced the secretions of IFN-γ and IL-2 significantly. Further immunofluorescence experiments and a docking study with NF-κB P65 showed that compound 13 interfered with the proliferation of HaCaT cells by inhibiting the NF-κB P65 phosphorylation at the protein level. Full article