Additive Effects of Cyclic Peptide [R4W4] When Added Alongside Azithromycin and Rifampicin against Mycobacterium avium Infection

Mycobacterium avium (M. avium), a type of nontuberculous mycobacteria (NTM), poses a risk for pulmonary infections and disseminated infections in immunocompromised individuals. Conventional treatment consists of a 12-month regimen of the first-line antibiotics rifampicin and azithromycin. However, the treatment duration and low antibiotic tolerability present challenges in the treatment of M. avium infection. Furthermore, the emergence of multidrug-resistant mycobacterium strains prompts a need for novel treatments against M. avium infection. This study aims to test the efficacy of a novel antimicrobial peptide, cyclic [R4W4], alongside the first-line antibiotics azithromycin and rifampicin in reducing M. avium survival. Colony-forming unit (CFU) counts were assessed after treating M. avium cultures with varying concentrations of cyclic [R4W4] alone or in conjunction with azithromycin or rifampicin 3 h and 4 days post-treatment. M. avium growth was significantly reduced 4 days after cyclic [R4W4] single treatment. Additionally, cyclic [R4W4]-azithromycin and cyclic [R4W4]-rifampicin combination treatments at specific concentrations significantly reduced M. avium survival 3 h and 4 days post-treatment compared with single antibiotic treatment alone. These findings demonstrate cyclic [R4W4] as a potent treatment method against M. avium and provide insight into novel therapeutic approaches against mycobacterium infections.

Liposomal Glutathione Supplementation Mitigates Extrapulmonary Tuberculosis in the Liver and Spleen

BACKGROUND

Extrapulmonary tuberculosis (EPTB) accounts for a fifth of all Mycobacterium tuberculosis (M. tb) infections worldwide. The rise of multidrug resistance in M. tb alongside the hepatotoxicity associated with antibiotics presents challenges in managing and treating tuberculosis (TB), thereby prompting a need for new therapeutic approaches. Administration of liposomal glutathione (L-GSH) has previously been shown to lower oxidative stress, enhance a granulomatous response, and reduce the burden of M. tb in the lungs of M. tb-infected mice. However, the effects of L-GSH supplementation during active EPTB in the liver and spleen have yet to be explored.

METHODS

In this study, we evaluated hepatic glutathione (GSH) and malondialdehyde (MDA) levels, and the cytokine profiles of untreated and L-GSH-treated M. tb-infected wild type (WT) mice. Additionally, the hepatic and splenic M. tb burdens and tissue pathologies were also assessed.

RESULTS

L-GSH supplementation increased total hepatic levels and reduced GSH. A decrease in the levels of MDA, oxidized GSH, and interleukin (IL)-6 was also detected following L-GSH treatment. Furthermore, L-GSH supplementation was observed to increase interferon-gamma (IFN-γ) and tumor necrosis factor (TNF)-α production and decrease IL-10 levels. M. tb survival was significantly reduced in the liver and spleen following L-GSH supplementation. L-GSH treatment also provided a host-protective effect in the liver and spleen of M. tb-infected mice.

CONCLUSIONS

Overall, L-GSH supplementation elevated the levels of total and reduced forms of GSH in the liver and reduced the burden of M. tb by decreasing oxidative stress, enhancing the production of immunosupportive cytokines, and reducing the levels of immunosuppressive cytokines. These observed benefits highlight the potential of L-GSH supplementation during active EPTB and provide insight into novel therapeutic interventions against M. tb infections.

Topical Absorption of Glutathione-Cyclodextrin Nanoparticle Complex in Healthy Human Subjects Improves Immune Response against Mycobacterium avium Infection

Glutathione (GSH) is an important intracellular antioxidant responsible for neutralizing reactive oxygen species (ROS). Our laboratory previously demonstrated that the oral administration of liposomal GSH improves immune function against mycobacterium infections in healthy patients along with patients with HIV and Type 2 diabetes. We aim to determine if the topical application of a glutathione-cyclodextrin nanoparticle complex (GSH-CD) confers a therapeutic effect against mycobacterium infections. In our study, healthy participants received either topical GSH-CD (n = 15) or placebo (n = 15) treatment. Subjects were sprayed four times twice a day for three days topically on the abdomen. Blood draws were collected prior to application, and at 1, 4, and 72 h post-initial topical application. GSH, malondialdehyde (MDA), and cytokine levels were assessed in the processed blood samples of study participants. Additionally, whole blood cultures from study participants were challenged with Mycobacterium avium (M. avium) infection in vitro to assess mycobacterium survival post-treatment. Topical GSH-CD treatment was observed to elevate GSH levels in peripheral blood mononuclear cells (PBMCs) and red blood cells and decrease MDA levels in PBMCs 72 h post-treatment. An increase in plasma IL-2, IFN-γ, IL-12p70, and TNF-α was observed at 72 h post-topical GSH-CD treatment. Enhanced mycobacterium clearance was observed at 4 h and 72 h post-topical GSH-CD treatment. Overall, topical GSH-CD treatment was associated with improved immune function against M. avium infection. The findings of this pilot study suggest GSH-cyclodextrin complex formulation can be used topically as a safe alternative mode of GSH delivery in the peripheral blood.

Glutathione Modulates Efficacious Changes in the Immune Response against Tuberculosis

Glutathione (GSH) is an antioxidant in human cells that is utilized to prevent damage occurred by reactive oxygen species, free radicals, peroxides, lipid peroxides, and heavy metals. Due to its immunological role in tuberculosis (TB), GSH is hypothesized to play an important part in the immune response against M. tb infection. In fact, one of the hallmark structures of TB is granuloma formation, which involves many types of immune cells. T cells, specifically, are a major component and are involved in the release of cytokines and activation of macrophages. GSH also serves an important function in macrophages, natural killer cells, and T cells in modulating their activation, their metabolism, proper cytokine release, proper redox activity, and free radical levels. For patients with increased susceptibility, such as those with HIV and type 2 diabetes, the demand for higher GSH levels is increased. GSH acts as an important immunomodulatory antioxidant by stabilizing redox activity, shifting of cytokine profile toward Th1 type response, and enhancing T lymphocytes. This review compiles reports showing the benefits of GSH in improving the immune responses against M. tb infection and the use of GSH as an adjunctive therapy for TB.

Pathogenicity of Type I Interferons in Mycobacterium tuberculosis

Tuberculosis (TB) is a leading cause of mortality due to infectious disease and rates have increased during the emergence of COVID-19, but many of the factors determining disease severity and progression remain unclear. Type I Interferons (IFNs) have diverse effector functions that regulate innate and adaptive immunity during infection with microorganisms. There is well-documented literature on type I IFNs providing host defense against viruses; however, in this review, we explore the growing body of work that indicates high levels of type I IFNs can have detrimental effects to a host fighting TB infection. We report findings that increased type I IFNs can affect alveolar macrophage and myeloid function, promote pathological neutrophil extracellular trap responses, inhibit production of protective prostaglandin 2, and promote cytosolic cyclic GMP synthase inflammation pathways, and discuss many other relevant findings.

Recent Developments in the Understanding of Immunity, Pathogenesis and Management of COVID-19

Coronaviruses represent a diverse family of enveloped positive-sense single stranded RNA viruses. COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus-2, is a highly contagious respiratory disease transmissible mainly via close contact and respiratory droplets which can result in severe, life-threatening respiratory pathologies. It is understood that glutathione, a naturally occurring antioxidant known for its role in immune response and cellular detoxification, is the target of various proinflammatory cytokines and transcription factors resulting in the infection, replication, and production of reactive oxygen species. This leads to more severe symptoms of COVID-19 and increased susceptibility to other illnesses such as tuberculosis. The emergence of vaccines against COVID-19, usage of monoclonal antibodies as treatments for infection, and implementation of pharmaceutical drugs have been effective methods for preventing and treating symptoms. However, with the mutating nature of the virus, other treatment modalities have been in research. With its role in antiviral defense and immune response, glutathione has been heavily explored in regard to COVID-19. Glutathione has demonstrated protective effects on inflammation and downregulation of reactive oxygen species, thereby resulting in less severe symptoms of COVID-19 infection and warranting the discussion of glutathione as a treatment mechanism.

Targeting EZH2 Selectively Alters Intratumoral Regulatory T Cells to Enhance Cancer Immunity

Immunosuppressive regulatory T cells (Tregs) are critical for maintaining immune homeostasis, but their presence in tumor tissues impairs anti-tumor immunity and portends poor prognoses in cancer patients. Targeting Tregs may be a powerful means to unleash more potent immune responses against cancer, but targeting these cells is challenging because their generalized inactivation may incite severe autoimmune toxicities. To selectively target Tregs in tumors, we investigated the role of the H3K27 methyltransferase EZH2 in Tregs and determined that its enhanced activity at tumor sites in mice and humans leads to more robust and stable Tregs. We demonstrate that blocking EZH2 activity, both pharmacologically and genetically, selectively reprograms the function of tumor-infiltrating Tregs without systemically altering Treg function. Genetic disruption of EZH2 in tumor-resident Tregs led to their acquisition of pro-inflammatory functions that remodeled the tumor microenvironment and enhanced the recruitment and function of effector T cells, leading to the complete elimination of tumors. Moreover, abolishing EZH2 function in Tregs was mechanistically distinct from, more potent than, and less toxic than a generalized Treg depletion approach. This study reveals a novel strategy to target Tregs in cancer that mitigates autoimmunity by reprogramming their function in tumors to enhance anti-cancer immunity.