Biology subjects

Praharaj, M.

Publications and source records attributed to Praharaj, M..

4 recordsLinked to original sources

bioRxiv2023

Improved bladder cancer antitumor efficacy with a recombinant BCG that releases a STING agonist

Despite the introduction of several new agents for the treatment of bladder cancer (BC), intravesical BCG remains a first line agent for the management of non-muscle invasive bladder cancer. In this study we evaluated the antitumor efficacy in animal models of BC of a recombinant BCG known as BCG-disA-OE that releases the small molecule STING agonist c-di-AMP. We found that compared to wild-type BCG (BCG-WT), in both the orthotopic, carcinogen-induced rat MNU model and the heterotopic syngeneic mouse MB-49 model BCG-disA-OE afforded improved antitumor efficacy. A mouse safety evaluation further revealed that BCG-disA-OE proliferated to lesser degree than BCG-WT in BALB/c mice and displayed reduced lethality in SCID mice. To probe the mechanisms that may underlie these effects, we found that BCG-disA-OE was more potent than BCG-WT in eliciting IFN-{beta} release by exposed macrophages, in reprogramming myeloid cell subsets towards an M1-like proinflammatory phenotypes, inducing epigenetic activation marks in proinflammatory cytokine promoters, and in shifting monocyte metabolomic profiles towards glycolysis. Many of the parameters elevated in cells exposed to BCG-disA-OE are associated with BCG-mediated trained innate immunity suggesting that STING agonist overexpression may enhance trained immunity. These results indicate that modifying BCG to release high levels of proinflammatory PAMP molecules such as the STING agonist c-di-AMP can enhance antitumor efficacy in bladder cancer.

cancer biology↗

bioRxiv2022

Dynamic single-cell RNA sequencing reveals BCG vaccination curtails SARS-CoV-2 induced disease severity and lung inflammation

COVID-19 continues to exact a toll on human health despite the availability of several vaccines. Bacillus Calmette Guerin (BCG) has been shown to confer heterologous immune protection against viral infections including COVID-19 and has been proposed as vaccine against SARS-CoV-2 (SCV2). Here we tested intravenous BCG vaccination against COVID-19 using the golden Syrian hamster model together with immune profiling and single cell RNA sequencing (scRNAseq). We observed that BCG reduced both lung SCV2 viral load and bronchopneumonia. This was accompanied by an increase in lung alveolar macrophages, a reversal of SCV2-mediated T cell lymphopenia, and reduced lung granulocytes. Single cell transcriptome profiling showed that BCG uniquely recruits immunoglobulin-producing plasma cells to the lung suggesting accelerated antibody production. BCG vaccination also recruited elevated levels of Th1, Th17, Treg, CTLs, and Tmem cells, and differentially expressed gene (DEG) analysis showed a transcriptional shift away from exhaustion markers and towards antigen presentation and repair. Similarly, BCG enhanced lung recruitment of alveolar macrophages and reduced key interstitial macrophage subsets, with both cell-types also showing reduced IFN-associated gene expression. Our observations indicate that BCG vaccination protects against SCV2 immunopathology by promoting early lung immunoglobulin production and immunotolerizing transcriptional patterns among key myeloid and lymphoid populations.

immunology↗

bioRxiv2020

Recombinant BCG overexpressing a STING agonist elicits trained immunity and improved antitumor efficacy in non-muscle invasive bladder

Withdrawal StatementThe authors have withdrawn their manuscript owing to irregularities in the Source Data supporting some figures. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding authors.

cancer biology↗

bioRxiv2018

BCG overexpressing an endogenous STING agonist provides enhanced protection against pulmonary tuberculosis

Stimulator of interferon genes (STING) has emerged as a key signaling receptor that induces proinflammatory cytokines, and small molecule STING agonists are being developed as anticancer and antiviral agents. Here we report a strategy of delivering a STING agonist from within live BCG. We generated a recombinant BCG (BCG-disA-OE) that overexpresses the endogenous mycobacterial diadenylate cyclase gene and releases high levels of the STING agonist c-di-AMP. In macrophages BCG-disA-OE elicited statistically significantly stronger TNF-, IL-6, IL-1{beta}, IRF3, and IFN-{beta} levels than BCG-WT. In a 24-week guinea pig vaccination-Mtb challenge model, BCG-disA-OE reduced lung weights, pathology scores, and Mtb CFU counts in lungs by 28% (p<0.05), 34%, and 2.0 log10 CFU units (p < 0.5) compared with BCG-WT, respectively. Overproduction of the STING agonist c-di-AMP significantly enhanced the protective efficacy of BCG against pulmonary and extrapulmonary tuberculosis. Our findings support the development of BCG-vectored STING agonists as a TB vaccine strategy.

microbiology↗