Breaking the Cycle: Matrix Metalloproteinase Inhibitors as an Alternative Approach in Managing Tuberculosis Pathogenesis and Progression

Discovery and Characterisation of Novel Poly-Histidine-Poly-Glycine Peptides as Matrix Metalloproteinase Inhibitors

For the first time, two poly-histidine-poly-glycine peptides (pHpG-H5 and pHpG-H7) were identified as promising candidates for matrix metalloproteinase inhibitors. cDNAs encoding pHpG-H5 and pHpG-H7 peptides were isolated from the Atheris squamigera cDNA library constructed using oligo(dT)-primed reverse transcription. Deduced sequences of pHpG peptides were systematically organised and utilised as templates for synthesising chemical replicates. All synthetic pHpG peptides exhibited inhibitory effects on human matrix metalloproteinase-1 (MMP-1). Spectroscopic analyses and molecular modelling demonstrated that pHpG peptides disrupt zinc ion coordination within the central catalytic domain of MMP-1, thereby inhibiting its enzymatic activity. As a novel peptide inhibitor of matrix metalloproteinase, pHpG-H7 modulates multiple biological processes, such as cell migration and angiogenesis, suggesting significant therapeutic potential.

Targeted Nasal Route Delivery of Cationic Anti-TB Drug-Loaded Nano-embedded Microparticles for Mycobacterial Elimination in the CNS

Central nervous system tuberculosis (CNS-TB) is a severe and insidious form of extrapulmonary tuberculosis (TB) associated with a high mortality rate, often leading to fatal outcomes or debilitating neurological impairments. The therapeutic regimen for CNS-TB follows an approach similar to that of pulmonary TB but faces significant challenges in effectively reaching the cerebrospinal fluid and achieving therapeutic drug levels in the brain and surrounding fluids. A major obstacle in CNS-TB treatment is the difficulty in permeating the blood-brain barrier (BBB). The nasal route of drug delivery offers a promising approach for targeting anti-TB drugs directly to the infection sites, enabling higher drug concentrations while bypassing the BBB. The present study focused on the development of cationic poly(lactic-co-glycolic) acid (PLGA) nanoparticles (CS-PLGA NPs) loaded with anti-TB drugs (ATDs), namely, isoniazid (INH) and rifampicin (RIF). These CS-PLGA NPs were then processed into dynamic microsized nanoembedded microparticles (NEMs) using spray drying. The ATD-NEMs formulation demonstrated significantly enhanced permeation across RPMI 2650 nasal septum monolayers compared with free ATDs. Intranasal delivery of the NEM formulation to TB-infected mice over a four-week period resulted in a substantial reduction in colony-forming units (CFUs) (1.53 ± 0.50 log10 CFU/gram) compared to the untreated group (4.45 ± 0.67 log10 CFU/gram). Furthermore, the NEM formulation showed improved recovery in histopathological analysis, consistent with CFU reduction. Preclinical data support the feasibility of intranasally administering the NEMs formulation, demonstrating high therapeutic efficacy and the potential to address brain inflammation in the murine CNS-TB model.

The role of neutrophil response in lung damage and post-tuberculosis lung disease: a translational narrative review

It is estimated that more than 150 million individuals alive in 2020 had survived tuberculosis (TB). A portion of this large population continues to experience chronic respiratory abnormalities, with or without symptoms, due to previous active pulmonary TB. This condition known as Post-TB Lung Disease (PTLD), involves a complex interaction between pathogen, host and environmental factors. These interactions are believed to drive a hyperinflammatory process in the lungs during active TB, resulting in tissue damage, which may lead to radiological sequelae, impaired pulmonary function, clinical symptoms, such as cough, dyspnea, hemoptysis, and respiratory infections. Such complications impose significant health, financial, and social burdens, which remain poorly understood and inadequately addressed by health care systems. Given the heterogeneity of immune cells and their products infiltrating the airways and the lung parenchyma during acute and chronic inflammation caused by Mycobacterium tuberculosis infection, it is evident that TB immunopathology is multifactorial. Among the various components involved, neutrophils have recently emerged as critical contributors to the deleterious immune response against TB, leading to severe pulmonary damage. In this translational narrative review, we aim to summarize the role of neutrophils and their primary products - proteases (such as elastase), matrix metalloproteinases and neutrophils extracellular traps (NETs) - in pulmonary TB. We highlight new concepts and emerging evidence of neutrophil involvement during the active disease, translating these insights from "bench to bedside" to facilitate dialogue between fundamental researchers and clinical practitioners. Additionally, we present potential targets for future treatment strategies that could mitigate or even prevent PTLD.

Host-Directed Therapy with Inhalable Lovastatin Microspheres for Matrix Metalloproteinase Inhibition in Tuberculosis

Tuberculosis (TB) triggers a robust immune response, which leads to significant destruction of the lung tissue at the site of infection, aiding in the transmission of Mycobacterium tuberculosis (Mtb) to the hosts. The excessive inflammatory response contributes heavily to extracellular matrix (ECM) damage, which is linked to high mortality rates among TB patients. Matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9, are pivotal in the breakdown of the ECM, worsening tissue destruction. In the context of host-directed therapy (HDT), a strategy aimed at modulating the immune response rather than directly targeting the pathogen, we evaluated the potential of lovastatin (LOV). LOV has shown promise in reducing MMP activity and inflammation, which could alleviate the immune-mediated pathology in TB. However, its clinical use has been limited due to poor solubility and biocompatibility, reducing its therapeutic efficacy. To overcome these limitations, we designed inhalable gelatin microspheres (GA-MS) loaded with LOV using the spray-drying technology. This approach improved the solubility and allowed for the controlled release of the drug. The resulting LOV-loaded gelatin microspheres (LOV/GA-MS) had an optimal particle size of 2.395 ± 0.67 μm, facilitating macrophage uptake due to their aerodynamic properties. In in vitro studies using Mtb-infected macrophages, LOV/GA-MS effectively suppressed MMP expression and reduced levels of pro-inflammatory cytokines at a concentration of 20 μg/mL, demonstrating substantial anti-inflammatory potential. Moreover, these microspheres showed a synergistic effect when combined with standard anti-TB drugs, enhancing the overall therapeutic efficacy in in vitro experiments. The findings suggest that inhalable LOV/GA-MS microspheres represent a promising adjunctive host-directed therapy for TB. By modulating the host's immune response and targeting key inflammatory mediators such as MMPs, this approach could mitigate lung tissue damage, improve clinical outcomes, and provide a more holistic treatment option for TB.

Advances in Host-Pathogen Interactions in Tuberculosis: Emerging Strategies for Therapeutic Intervention

Tuberculosis (TB) remains one of the most challenging infectious diseases, with Mycobacterium tuberculosis (Mtb) employing sophisticated mechanisms to evade host immunity and establish persistent infections. This review explores recent advances in understanding Mtb's immune evasion strategies; granuloma dynamics; and emerging immunotherapeutic approaches. Key findings highlight the manipulation of host autophagy; metabolic reprogramming; and cytokine pathways by Mtb to sustain its survival within host cells. Insights into granuloma formation reveal the critical role of bacterial lipids; immune modulation; and hypoxia-driven dormancy in maintaining chronic infection. Innovative therapeutic strategies, including host-directed therapies; epigenetic interventions; and immunomodulators, hold promise for improving TB management and combating drug-resistant strains. Despite these advancements, significant challenges remain, including the development of effective vaccines; addressing latent TB; and ensuring equitable access to novel treatments. The integration of advanced technologies such as artificial intelligence and multi-omics approaches, alongside global collaboration, is essential to overcome these hurdles. This review underscores the importance of a multidisciplinary approach to tackling TB, with the ultimate goal of eradicating this global health threat.

Trans-nasal brain delivery of anti-TB drugs by methyl-β-cyclodextrin microparticles show efficient mycobacterial clearance from central nervous system

Central nervous system tuberculosis (CNS-TB) is the most severe extra-pulmonary manifestation of tuberculosis (TB), facing significant challenges due to the limited penetration of anti-TB drugs (ATDs) across the blood-brain barrier (BBB) and their insufficient concentrations at the site of infection. This study aimed to enhance the efficacy of ATDs by encapsulating them in methyl-β-cyclodextrin (M-β-CD) microparticles (ATD-MP) using spray drying, intended for intranasal delivery to manage CNS-TB. M-β-CD microparticles loaded with isoniazid (INH) and rifampicin (RIF) exhibited spherical shapes with slightly deflated surfaces and particle sizes of 6.24 ± 0.77 μm and 5.97 ± 0.50 μm, respectively. M-β-CD improved the permeation of ATDs through RPMI-2650 cell monolayers while reducing drug cytotoxicity. Pharmacokinetic and biodistribution analysis demonstrated that intranasal administration of ATD-MP significantly enhanced the trans-nasal brain delivery of ATDs and their distribution in the brain, achieving the minimum inhibitory concentration. In a murine model of CNS-TB, intranasal insufflation of ATD-MP for four weeks led to a significant reduction (∼0.78 Log10 CFU) in mycobacterial burden in the brain compared to the untreated group (∼3.60 Log10 CFU). These preclinical results underscore the potential of intranasal administration of M-β-CD microparticles as an effective therapeutic strategy for combating brain inflammation in CNS-TB.

Matrix Metalloproteinases in Health and Disease 3.0

Matrix metalloproteinases (MMPs) are members of an enzyme family that are critical for maintaining tissue allostasis [...].