Biology subjects

Vankayalapati, R.

Publications and source records attributed to Vankayalapati, R..

3 recordsLinked to original sources

bioRxiv2023

HIV-differentiated metabolite N-Acetyl-L-Alanine dysregulates human natural killer cell responses to Mycobacterium tuberculosis infection

BackgroundMycobacterium tuberculosis (Mtb) has latently infected over two billion people worldwide (LTBI) and causes 1.8 million deaths each year. Human immunodeficiency virus (HIV) co-infection with Mtb will affect the Mtb progression and increase the risk of developing active tuberculosis by 10-20 times compared to the HIV-LTBI+ patients. It is crucial to understand how HIV can dysregulate immune responses in LTBI+ individuals. MethodsPlasma samples collected from healthy and HIV-infected individuals were investigated by liquid chromatography-mass spectrometry (LC-MS), and the metabolic data were analyzed using an online platform Metabo-Analyst. ELISA, surface and intracellular staining, flow cytometry, quantitative reverse transcription PCR (qRT-PCR) were performed by standard procedure to determine the surface markers, cytokines and other signaling molecule expression. Seahorse extra cellular flux assays were used to measure the mitochondrial oxidative phosphorylation and glycolysis. ResultsSix metabolites were significantly less abundant, and two were significantly higher in abundance in HIV+ individuals compared to healthy donors. One of the HIV-upregulated metabolites, N-Acetyl-L-Alanine (ALA), inhibits pro-inflammatory cytokine IFN-{square} production by NK cells of LTBI+ individuals. ALA inhibits glycolysis of LTBI+ individuals NK cells in response to Mtb. ConclusionsOur findings demonstrate that HIV infection enhances plasma ALA levels to inhibit NK cell-mediated immune responses to Mtb infection, offering a new understanding of the HIV-Mtb interaction and providing the implication of nutrition intervention and therapy for HIV-Mtb co-infected patients.

immunology↗

bioRxiv2023

Bacteriophage therapy for the treatment of Mycobacterium tuberculosis infections in humanized mice

The continuing emergence of new strains of antibiotic-resistant bacteria has renewed interest in phage therapy; however, there has been limited progress in applying phage therapy to multi-drug resistant Mycobacterium tuberculosis (Mtb) infections. In this study, we tested three bacteriophage strains for their Mtb-killing activities and found that two of them efficiently lysed Mtb H37Rv in 7H10 agar plates. However, only phage DS6A efficiently killed H37Rv in liquid culture and in Mtb-infected human primary macrophages. In subsequent experiments, we infected humanized mice with aerosolized H37Rv, then treated these mice with DS6A intravenously to test its in vivo efficacy. We found that DS6A treated mice showed increased body weight and improved pulmonary function relative to control mice. Furthermore, DS6A reduced Mtb load in mouse organs with greater efficacy in the spleen. These results demonstrated the feasibility of developing phage therapy as an effective therapeutic against Mtb infection.

microbiology↗

bioRxiv2020

Mycobacterium tuberculosis stimulates IL-1β production by macrophages in an ESAT-6 dependent manner with the involvement of serum amyloid A3

To explore interleukin (IL)-1{beta} production in tuberculosis, we infected mouse bone marrow-derived macrophages (BMDM) with Mycobacterium tuberculosis (Mtb) H37Rv, its early secreted antigenic target protein of 6 kDa (ESAT-6) gene deletion (H37Rv:{Delta}3875) or complemented strain (H37Rv:{Delta}3875C) and evaluated IL-1{beta} production. H37Rv induced significantly increased IL-1{beta} production by BMDMs compared to non-infected BMDMs. In contrast, H37Rv:{Delta}3875 induced significantly less mature IL-1{beta} production despite eliciting comparable levels of pro-IL-1{beta} and IL-8 from BMDMs compared to H37Rv and H37Rv:{Delta}3875C. Blocking either NLRP3 or K+ efflux diminished H37Rv-induced IL-1{beta} production by BMDMs. Infection of mice intranasally with H37Rv:{Delta}3875 induced less IL-1{beta} production in the lungs compared with H37Rv.Intranasal delivery of ESAT-6 but not CFP10 induced production of IL-1{beta} in mouse lungs and RNA-Seq analysis identified serum amyloid A (SAA) 3 as one of the highly expressed genes in mouse lungs. Infection of mice with H37Rv but not H37Rv:{Delta}3875 induced expression of lung SAA3 mRNA and protein, consistent with the effect of intranasal delivery of ESAT-6. Silencing SAA3 reduced Mtb-induced IL-1{beta} production by BMDMs. We conclude that the production of SAA3 is required for Mtb stimulated IL-1{beta} production by macrophages in tuberculosis infection.

immunology↗