Background/Objective: Finding new targets to attenuate Mycobacterium tuberculosis (Mtb) is key in the development of new TB vaccines. In this context, plasma membrane P-type ATPases are relevant for mycobacterial homeostasis and virulence. In this work, we investigate the role of the copper-transporting P-type ATPase CtpA in Mtb virulence. Methods: The impact of CtpA deletion on Mtb’s capacity to overcome redox stress and proliferate in mouse alveolar macrophages (MH-S) was evaluated, as well as its effect on Mtb immunogenicity. Moreover, the influence of CtpA on the pathogenicity of Mtb in a mouse (BALB/c) model of progressive TB was examined. Results: We found that MH-S cells infected with wild-type (MtbH37Rv) or the mutant strain (MtbH37RvΔctpA) showed no difference in Mtb bacterial load. However, the same macrophages under copper activation (50 µM CuSO₄) showed impaired replication of the mutant strain. Furthermore, the mutant MtbΔctpA strain showed an inability to control reactive oxygen species (ROS) induced by PMA addition during MH-S infection. These results, together with the high expression of the Nox2 mRNA observed in MH-S cells infected with the Mtb∆ctpA strain at 3 and 6 days post-infection, suggest a potential role for CtpA in overcoming redox stress under infection conditions. In addition, MtbΔctpA-infected BALB/c mice survived longer with significantly lower lung bacterial loads and tissue damage in their lungs than MtbH37Rv-infected mice. Conclusions: This suggests that CtpA is involved in Mtb virulence and that it may be a target for attenuation.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a global health challenge, partly due to the prolonged duration and toxicity of standard antibiotic regimens. Adjunctive therapies that enhance antimicrobial efficacy and modulate host immunity are urgently needed. Curcumin, a natural bioactive compound derived from Curcuma longa, possesses broad therapeutic properties, including anti-inflammatory, antioxidant, antibacterial, and antiviral effects. This study evaluated the effects of curcumin in combination with first- and second-line antibiotics against Mtb in both in vitro and in vivo models. Our results demonstrated that curcumin exerts direct antibacterial activity against both the drug-sensitive H37Rv strain and a multidrug-resistant (MDR) clinical isolate. Furthermore, curcumin synergized with conventional antibiotics, enhancing bacterial clearance in infected macrophages while promoting the production of IL-12, a key cytokine in protective immune responses. In a murine model of progressive pulmonary TB, combination therapy with curcumin and first-line antibiotics significantly reduced the lung bacterial burden and improved behavioral outcomes compared to antibiotic treatment alone. These findings suggest that curcumin acts through both direct antimicrobial mechanisms and immune modulation, supporting its potential as an adjunctive therapy agent for TB. Future studies should focus on optimizing curcumin formulation, dosing, and bioavailability to facilitate the clinical translation of this compound.

Tuberculosis (TB), an infection caused by Mycobacterium tuberculosis (Mtb), is one of the primary causes of death globally. The treatment of TB is long and based on several drugs, producing problems in compliance and toxicity, increasing Mtb resistance to first-line antibiotics that result in multidrug-resistant TB and extensively drug-resistant TB. Thus, the need for new anti-TB treatments has increased. Here, we review some model strategies to study gene therapy based on the administration of a recombinant adenovirus that encodes diverse cytokines, such as IFNγ, IL12, GM/CSF, OPN, TNFα, and antimicrobial peptides to enhance the protective immune response against Mtb. These models include a model of progressive pulmonary TB, a model of chronic infection similar to latent TB, and a murine model of pulmonary Mtb transmission to close contacts. We also review new vaccines that deliver Mtb antigens via particle- or virus-based vectors and trigger protective immune responses. The results obtained in this type of research suggest that this is an alternative therapy that has the potential to treat active TB as an adjuvant to conventional antibiotics and a promising preventive treatment for latent TB reactivation and Mtb transmission. Moreover, Ad vector vaccines are adequate for preventing infectious diseases, including TB.

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.

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis, is a leading cause of morbidity worldwide. Along with CD4+ T lymphocytes, macrophages serve as key pillars of the immune response against this intracellular pathogen, which is essential for the prompt and effective elimination of the bacilli. Many strategies have been developed to enhance the microbicidal performance of macrophages; among them, stimulation with polymeric microparticles is one of the most promising. Exposition of infected macrophages to these microparticles may enhance non-specific innate immune mechanisms such as the promotion of phagocytosis, the induction of proinflammatory cytokines, and the production of reactive oxygen intermediates (ROI), contributing to the elimination of mycobacteria. Here, we evaluated the in vitro effect of starch microparticles (SMPs) on the activation and microbicidal activity of infected alveolar macrophages. The results demonstrate that these alpha-glucan microparticles are efficiently phagocytosed by infected macrophages and promote cellular activation, inducing reactive oxygen and nitrogen species, moderate apoptosis, and modulating cytokine and chemokine production without causing an excessive proinflammatory response. These effects contributed to the elimination of tubercle bacilli when SMPs were administered after infection, suggesting their usefulness as a post-exposure treatment that activates macrophages against the pathogen.