Rv0547c, a functional oxidoreductase, supports Mycobacterium tuberculosis persistence by reprogramming host mitochondrial fatty acid metabolism.

Mycobacterium tuberculosis (Mtb) successfully thrives in the host by adjusting its metabolism and manipulating the host environment. In this study, we investigated the role of Rv0547c, a protein that carries mitochondria-targeting sequence (MTS), in mycobacterial persistence. We show that Rv0547c is a functional oxidoreductase that targets host-cell mitochondria. Interestingly, the localization of Rv0547c to mitochondria was independent of the predicted MTS but depended on specific arginine residues at the N- and C-terminals. As compared to the mitochondria-localization defective mutant, Rv0547c-2SDM, wild-type Rv0547c increased mitochondrial membrane fluidity and spare respiratory capacity. To comprehend the possible reason, comparative lipidomics was performed that revealed a reduced variability of long-chain and very long-chain fatty acids as well as altered levels of phosphatidylcholine and phosphatidylinositol class of lipids upon expression of Rv0547c, explaining the increased membrane fluidity. Additionally, the over representation of propionate metabolism and ß-oxidation intermediates in Rv0547c-targeted mitochondrial fractions indicated altered fatty acid metabolism, which corroborated with changes in oxygen consumption rate (OCR) upon etomoxir treatment in HEK293T cells transiently expressing Rv0547c, resulting in enhanced mitochondrial fatty acid oxidation capacity. Furthermore, Mycobacterium smegmatis over expressing Rv0547c showed increased persistence during infection of THP-1 macrophages, which correlated with its increased expression in Mtb during oxidative and nutrient starvation stresses. This study identified for the first time an Mtb protein that alters mitochondrial metabolism and aids in survival in host macrophages by altering fatty acid metabolism to its benefit and, at the same time increases mitochondrial spare respiratory capacity to mitigate infection stresses and maintain cell viability.

Confronting Tuberculosis: A Synthetic Quinoline-Isonicotinic Acid Hydrazide Hybrid Compound as a Potent Lead Molecule Against Mycobacterium tuberculosis.

The current tuberculosis (TB) treatment is challenged by a complex first-line treatment for drug-sensitive (DS) TB. Additionally, the prevalence of multidrug (MDR)- and extensively drug (XDR)-resistant TB necessitates the search for new drug prototypes. We synthesized and screened 30 hybrid compounds containing aminopyridine and 2-chloro-3-formyl quinoline to arrive at a compound with potent antimycobacterial activity, UH-NIP-16. Subsequently, antimycobacterial activity against DS and MDR Mycobacterium tuberculosis (M.tb) strains were performed. It demonstrated an MIC50 value of 1.86 ± 0.21 µM for laboratory pathogenic M.tb strain H37Rv and 3.045 ± 0.813 µM for a clinical M.tb strain CDC1551. UH-NIP-16 also decreased the MIC50 values of streptomycin, isoniazid, ethambutol, and bedaquiline to about 45, 55, 68, and 76%, respectively, when used in combination, potentiating their activities. The molecule was active against a clinical MDR M.tb strain. Cytotoxicity on PBMCs from healthy donors and on human cell lines was found to be negligible. Further, blind docking of UH-NIP-16 using Auto Dock Vina and MGL tools onto diverse M.tb proteins showed high binding affinities with multiple M.tb proteins, the top five targets being metabolically critical proteins CelA1, DevS, MmaA4, lysine acetyltransferase, and immunity factor for tuberculosis necrotizing toxin. These bindings were confirmed by fluorescence spectroscopy using a representative protein, MmaA4. Envisaging that a pathogen will have a lower probability of developing resistance to a hybrid molecule with multiple targets, we propose that UH-NIP-16 can be further developed as a lead molecule with the bacteriostatic potential against M.tb, both alone and in combination with first-line drugs.

Mycobacterium tuberculosis EspR modulates Th1-Th2 shift by transcriptionally regulating IL-4, steering increased mycobacterial persistence and HIV propagation during co-infection.

Mycobacterium tuberculosis (Mtb) and HIV are known to mutually support each other during co-infection by multiple mechanisms. This synergistic influence could be either by direct interactions or indirectly through secreted host or pathogen factors that work in trans. Mtb secretes several virulence factors to modulate the host cellular environment for its persistence and escaping cell-intrinsic immune responses. We hypothesized that secreted Mtb transcription factors that target the host nucleus can directly interact with host DNA element(s) or HIV LTR during co-infection, thereby modulating immune gene expression, or driving HIV transcription, helping the synergistic existence of Mtb and HIV. Here, we show that the Mtb-secreted protein, EspR, a transcription regulator, increased mycobacterial persistence and HIV propagation during co-infection. Mechanistically, EspR localizes to the nucleus of the host cells during infection, binds to its putative cognate motif on the promoter region of the host IL-4 gene, activating IL-4 gene expression, causing high IL-4 titers that induce a Th2-type microenvironment, shifting the macrophage polarization to an M2 state as evident from CD206 dominant population over CD64. This compromised the clearance of the intracellular mycobacteria and enhanced HIV propagation. It was interesting to note that EspR did not bind to HIV LTR, although its transient expression increased viral propagation. This is the first report of an Mtb transcription factor directly regulating a host cytokine gene. This augments our understanding of the evolution of Mtb immune evasion strategies and unveils how Mtb aggravates comorbidities, such as HIV co-infection, by modulating the immune microenvironment.

Natural protein-based electrospun nanofibers for advanced healthcare applications: progress and challenges.

Electrospinning is an electrostatic fiber fabrication technique that operates by the application of a strong electric field on polymer solution or melts. It is used to fabricate fibers whose size lies in the range of few microns to the nanometer range. Historic development of electrospinning has evinced attention due to its outstanding attributes such as small diameter, excellent pore inter-connectivity, high porosity, and high surface-to-volume ratio. This review aims to highlight the theory behind electrospinning and the machine setup with a detailed discussion about the processing parameters. It discusses the latest innovations in natural protein-based electrospun nanofibers for health care applications. Various plant- and animal-based proteins have been discussed with detailed sample preparation and corresponding processing parameters. The usage of these electrospun nanofibers in regenerative medicine and drug delivery has also been discussed. Some technical innovations in electrospinning techniques such as emulsion electrospinning and coaxial electrospinning have been highlighted. Coaxial electrospun core-shell nanofibers have the potential to be utilized as an advanced nano-architecture for sustained release targeted delivery as well as for regenerative medicine. Healthcare applications of nanofibers formed via emulsion and coaxial electrospinning have been discussed briefly. Electrospun nanofibers have still much scope for commercialization on large scale. Some of the available wound-dressing materials have been discussed in brief.

Prediction of novel pluripotent proteins involved in reprogramming of male Germline stem cells (GSCs) into multipotent adult Germline stem cells (maGSCs) by network analysis.

Germline stem cells (GSCs) are known to transmit genetic information from parents to offspring. These GSCs can undergo reprogramming to transform themselves into pluripotent stem cells, called as Multipotent adult Germline stem cells (maGSCs). The mechanism of the reprogramming of GSCs to maGSCs is elusive. To investigate novel factors that may govern the process of reprogramming, the RNA-seq data of both GSCs and maGSCs were retrieved and subjected to Tuxedo protocol using Galaxy server. Total 1558 differentially expressed genes were identified from the analysis. Protein sequence in the FASTA format of all 1558 differentially expressed genes was retrieved and submitted to Pluripred web server to predict whether the proteins were pluripotent or not. A total of 232 proteins were predicted as pluripotent, and to identify the novel proteins, these were submitted to STRING database to obtain an interaction map. The obtained interaction map was submitted to Cytoscape, and various apps such as MCODE and Centiscape were used to identify the clusters and centrality measures between the nodes of the generated network. Five clusters were identified and ranked according to their score. Novel pluripotent proteins like cadherin related cdh5, cdh10 were predicted. Phox2b, Nrp2, Dll1, Shh, Gbx2, Nodal, Lefty1, Wnt7b, Pitx2, fgf4, Pou5f1, Nanog, Tet1, trim8, alx2, Dppa2, Prdm14,Sox11, Esrrb were predicted to be involved in the stem cell development. Dppa2, Sox11, Sox2, Bmp4, Shh, and Otp were predicted to be involved in positive regulation of the stem cell proliferation. Pathway analysis further revealed that signaling pathways such as Wnt, Jak-Stat and PI3K may play important role in the pluripotency of the maGSCs. Novel proteins involved in pluripotency, which were predicted by our findings, can be experimentally researched in future.