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"Malik, Ankit"
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Fecal microbiota transplant rescues mice from human pathogen mediated sepsis by restoring systemic immunity
2020
Death due to sepsis remains a persistent threat to critically ill patients confined to the intensive care unit and is characterized by colonization with multi-drug-resistant healthcare-associated pathogens. Here we report that sepsis in mice caused by a defined four-member pathogen community isolated from a patient with lethal sepsis is associated with the systemic suppression of key elements of the host transcriptome required for pathogen clearance and decreased butyrate expression. More specifically, these pathogens directly suppress interferon regulatory factor 3. Fecal microbiota transplant (FMT) reverses the course of otherwise lethal sepsis by enhancing pathogen clearance via the restoration of host immunity in an interferon regulatory factor 3-dependent manner. This protective effect is linked to the expansion of butyrate-producing Bacteroidetes. Taken together these results suggest that fecal microbiota transplantation may be a treatment option in sepsis associated with immunosuppression.
Sepsis due to multidrug resistant pathogens is the most common cause of death in intensive care units. Here, the authors report that fecal microbiota transplant (FMT) can rescue mice from lethal sepsis of pathogens isolated from stool of a critically ill patient and show that FMT reverses the immunosuppressive effect induced by the pathogen community.
Journal Article
Bimetallic Au–Ag Nanoparticles: Advanced Nanotechnology for Tackling Antimicrobial Resistance
by
Mehata, Abhishesh Kumar
,
Malik, Ankit Kumar
,
Singh, Sanjeev K.
in
antibacterial
,
Antibiotics
,
Antimicrobial agents
2022
To date, there are no antimicrobial agents available in the market that have absolute control over the growing threat of bacterial strains. The increase in the production capacity of antibiotics and the growing antibacterial resistance of bacteria have majorly affected a variety of businesses and public health. Bimetallic nanoparticles (NPs) with two separate metals have been found to have stronger antibacterial potential than their monometallic versions. This enhanced antibacterial efficiency of bimetallic nanoparticles is due to the synergistic effect of their participating monometallic counterparts. To distinguish between bacteria and mammals, the existence of diverse metal transport systems and metalloproteins is necessary for the use of bimetallic Au–Ag NPs, just like any other metal NPs. Due to their very low toxicity toward human cells, these bimetallic NPs, particularly gold–silver NPs, might prove to be an effective weapon in the arsenal to beat emerging drug-resistant bacteria. The cellular mechanism of bimetallic nanoparticles for antibacterial activity consists of cell membrane degradation, disturbance in homeostasis, oxidative stress, and the production of reactive oxygen species. The synthesis of bimetallic nanoparticles can be performed by a bottom-up and top-down strategy. The bottom-up technique generally includes sol-gel, chemical vapor deposition, green synthesis, and co-precipitation methods, whereas the top-down technique includes the laser ablation method. This review highlights the key prospects of the cellular mechanism, synthesis process, and antibacterial capabilities against a wide range of bacteria. Additionally, we also discussed the role of Au–Ag NPs in the treatment of multidrug-resistant bacterial infection and wound healing.
Journal Article
Vitamin E TPGS-Based Nanomedicine, Nanotheranostics, and Targeted Drug Delivery: Past, Present, and Future
by
Mehata, Abhishesh Kumar
,
Vikas, Vikas
,
Malik, Ankit Kumar
in
Antioxidants
,
Bioavailability
,
Cancer therapies
2023
It has been seventy years since a water-soluble version of vitamin E called tocophersolan (also known as TPGS) was produced; it was approved by USFDA in 1998 as an inactive ingredient. Drug formulation developers were initially intrigued by its surfactant qualities, and gradually it made its way into the toolkit of pharmaceutical drug delivery. Since then, four drugs with TPGS in their formulation have been approved for sale in the United States and Europe including ibuprofen, tipranavir, amprenavir, and tocophersolan. Improvement and implementation of novel diagnostic and therapeutic techniques for disease are goals of nanomedicine and the succeeding field of nanotheranostics. Specifically, imaging and treating tumors with nanohybrid theranostics shows promising potential. Docetaxel, paclitaxel, and doxorubicin are examples of poorly bioavailable therapeutic agents; hence, much effort is applied for developing TPGS-based nanomedicine, nanotheranostics, and targeted drug delivery systems to increase circulation time and promote the reticular endothelial escape of these drug delivery systems. TPGS has been used in a number of ways for improving drug solubility, bioavailability improvement, and prevention of drug efflux from the targeted cells, which makes it an excellent candidate for therapeutic delivery. Through the downregulation of P-gp expression and modulation of efflux pump activity, TPGS can also mitigate multidrug resistance (MDR). Novel materials such as TPGS-based copolymers are being studied for their potential use in various diseases. In recent clinical trials, TPGS has been utilized in a huge number of Phase I, II, and III studies. Additionally, numerous TPGS-based nanomedicine and nanotheranostic applications are reported in the literature which are in their preclinical stage. However, various randomized or human clinical trials have been underway for TPGS-based drug delivery systems for multiple diseases such as pneumonia, malaria, ocular disease, keratoconus, etc. In this review, we have emphasized in detail the review of the nanotheranostics and targeted drug delivery approaches premised on TPGS. In addition, we have covered various therapeutic systems involving TPGS and its analogs with special references to its patent and clinical trials.
Journal Article
Epithelial IFNγ signalling and compartmentalized antigen presentation orchestrate gut immunity
by
Weber, Christopher
,
Zabala, Sarah
,
Sharma, Deepika
in
14/63
,
631/250/127/1212
,
631/250/21/1566
2023
All nucleated cells express major histocompatibility complex I and interferon‐γ (IFNγ) receptor
1
, but an epithelial cell-specific function of IFNγ signalling or antigen presentation by means of major histocompatibility complex I has not been explored. We show here that on sensing IFNγ, colonic epithelial cells productively present pathogen and self-derived antigens to cognate intra-epithelial T cells, which are critically located at the epithelial barrier. Antigen presentation by the epithelial cells confers extracellular ATPase expression in cognate intra-epithelial T cells, which limits the accumulation of extracellular adenosine triphosphate and consequent activation of the NLRP3 inflammasome in tissue macrophages. By contrast, antigen presentation by the tissue macrophages alongside inflammasome-associated interleukin-1α and interleukin-1β production promotes a pathogenic transformation of CD4
+
T cells into granulocyte–macrophage colony-stimulating-factor (GM-CSF)-producing T cells in vivo, which promotes colitis and colorectal cancer. Taken together, our study unravels critical checkpoints requiring IFNγ sensing and antigen presentation by epithelial cells that control the development of pathogenic CD4
+
T cell responses in vivo.
IFNγ signalling in epithelial cells promotes antigen presentation that confers intra-epithelial T cells the ability to limit extracellular ATP and consequent NLRP3 inflammasome activation, controlling pathogenic transformation of CD4
+
T cells that promotes colitis and colorectal cancer in mouse models.
Journal Article
IL-33 regulates the IgA-microbiota axis to restrain IL-1α–dependent colitis and tumorigenesis
2016
Inflammatory bowel diseases (IBD) affect over 5 million individuals in the industrialized world, with an increasing incidence rate worldwide. IBD also predisposes affected individuals to development of colorectal cancer, which is a leading cause of cancer-related deaths in adults. Mutations in genes encoding molecules in the IL-33 signaling pathway are associated with colitis and colitis-associated cancer (CAC), but how IL-33 modulates gut homeostasis is unclear. Here, we have shown that Il33-deficient mice are highly susceptible to colitis and CAC. Mechanistically, we observed that IL-33 promoted IgA production from B cells, which is important for maintaining microbial homeostasis in the intestine. Il33-deficient mice developed a dysbiotic microbiota that was characterized by increased levels of mucolytic and colitogenic bacteria. In response to chemically induced colitis, this microbial landscape promoted the release of IL-1α, which acted as a critical driver of colitis and CAC. Consequently, reconstitution of symbiotic microbiota or IL-1α ablation markedly ameliorated colitis susceptibility in Il33-deficient animals. Our results demonstrate that IL-33 promotes IgA production to maintain gut microbial homoeostasis and restrain IL-1α-dependent colitis and CAC. This study therefore highlights modulation of IL-33, IgA, IL-1α, and the microbiota as a potential therapeutic approach in the treatment of IBD and CAC.
Journal Article
TNF/TNFR axis promotes pyrin inflammasome activation and distinctly modulates pyrin inflammasomopathy
2019
Pyrin is an inflammasome sensor that promotes caspase-1-mediated pyroptotic cell death and maturation of proinflammatory cytokines IL-1β and IL-18. Familial Mediterranean fever (FMF), an autoinflammatory disorder, is associated with mutations in the gene encoding pyrin (MEFV). FMF-knockin (FMF-KI) mice that express chimeric pyrin protein with FMF mutation (MefvV726A/V726A) exhibit an autoinflammatory disorder mediated by autoactivation of the pyrin inflammasome. Increase in the levels of TNF are observed in FMF-KI mice, and many features of FMF overlap with the autoinflammatory disorder associated with TNF receptor signaling. In this study, we assessed the contribution of TNF signaling to pyrin inflammasome activation and its consequent role in distinct FMF pathologies. TNF signaling promoted the expression of pyrin in response to multiple stimuli and was required for inflammasome activation in response to canonical pyrin stimuli and in myeloid cells from FMF-KI mice. TNF signaling promoted systemic wasting, anemia, and neutrophilia in the FMF-KI mice. Further, TNF-induced pathology was induced specifically through the TNFR1 receptor, while TNFR2-mediated signaling was distinctly protective in colitis and ankle joint inflammation. Overall, our data show that TNF is a critical modulator of pyrin expression, inflammasome activation, and pyrin-inflammasomopathy. Further, specific blockade of TNFR1 or activation of TNFR2 could provide substantial protection against FMF pathologies.
Journal Article
Protective Role of β-arrestin2 in Colitis Through Modulation of T-cell Activation
by
Lucas, Peter C.
,
Steury, Michael D.
,
Parameswaran, Narayanan
in
Animals
,
Arrestins - deficiency
,
Arrestins - genetics
2015
β-arrestin2 (β-arr2), identified as a scaffolding protein in G-protein-coupled receptor desensitization, is a negative regulator of inflammation in polymicrobial sepsis. In this study, we wanted to investigate the role of β-arr2 in intestinal inflammation, a site of persistent microbial stimulation. In the absence of β-arr2, mice exhibited greater extent of mucosal inflammation determined by cellular infiltration and expression of inflammatory mediators even under homeostatic conditions. Furthermore, β-arr2–deficient mice were more susceptible to dextran sulfate sodium–induced colitis as demonstrated by greater body weight loss, higher disease activity index, and shortened colon as compared with wild-type mice. We also show that T cells from β-arr2 knockout mice exhibit altered activation status under both basal and colitic conditions, implicating their involvement in disease induction. Further assessment of the role of β-arr2 in intrinsic T-cell differentiation confirmed its importance in T-cell polarization. Using the T-cell transfer model of colitis, we demonstrate that T-cell–specific β-arr2 is important in limiting colitic inflammation; however, it plays a paradoxical role in concurrent systemic wasting disease. Together, our study highlights a critical negative regulatory role of β-arr2 in intestinal inflammation and demonstrates a distinct role of T-cell-specific β-arr2 in systemic wasting disease.
Journal Article
Poly(I:C) Priming Exacerbates Cecal Ligation and Puncture-Induced Polymicrobial Sepsis in Mice
by
Steury, Michael D
,
Nandakumar Packiriswamy
,
Parameswaran, Narayanan
in
Bacteria
,
Cecum
,
Cell activation
2018
Sepsis continues to be a major healthcare issue with one of the highest mortality rates in intensive care units. Toll-like receptors are pattern recognition receptors that are intricately involved in the pathogenesis of sepsis. TLR3 is a major receptor for double-stranded RNA and is largely associated with immunity to viral infection. In this study, we examined the role of TLR3 priming in the immunopathology of sepsis using cecal-ligation and puncture (CLP) model of sepsis in mice. Mice injected with vehicle or poly(I:C) were subjected to sham or CLP surgery and various parameters of sepsis, including mortality, inflammation, and bacterial clearance were assessed. Poly(I:C) pre-treatment significantly enhanced mortality in mice subjected to CLP. Consistent with this, inflammatory cytokines including TNFα, IL-12p40, IFNγ, and MCP-1 were enhanced both systemically and locally in the poly(I:C)-treated group compared to the vehicle control. In addition, bacterial load was significantly higher in the poly(I:C)-treated septic mice. These changes were associated with reduced macrophage activation (but not neutrophils) in the peritoneal cavity of poly(I:C) pre-treated mice compared to vehicle pre-treatment. Together our results demonstrate that poly(I:C) priming in sepsis is likely to be detrimental to the host due to effects on systemic inflammatory cytokines and bacterial clearance.
Journal Article
Population Structure of a Worldwide Collection of Tropical Japonica Rice Indicates Limited Geographic Differentiation and Shows Promising Genetic Variability Associated with New Plant Type
by
Singh, Vikram Jeet
,
Vinod, Kunnummal Kurungara
,
Bollinedi, Haritha
in
Alleles
,
center of origin
,
Genetic diversity
2022
Abating the approaching yield plateau in rice requires taking advantage of potential technologies that requires knowledge on genetic diversity. Hybrid breeding, particularly in indica rice, requires the recruitment of large genetic variability from outside because the available genetic diversity of the cultivated pool has already been utilized to a great extent. In this study, we examined an assembly of 200 tropical japonica lines collected worldwide for population genetic structure and variability in yield-associated traits. Tested along with 30 indica and six wild rice lines belonging to India, the tropical japonica lines indicated great phenotypic variability, particularly related to new plant type (NPT) phenology, and formed six clusters. Furthermore, a marker-based characterization using a universal diversity marker panel classified the genotype assembly into four clusters, of which three encompassed tropical japonica lines, while the last cluster included mostly indica lines. The population structure of the panel also revealed a similar pattern, with tropical japonica lines forming three subpopulations. Remarkable variation in the allelic distribution was observed between the subpopulations. Superimposing the geographical sources of the genotypes over the population structure did not reveal any pattern. The genotypes sourced closer to the center of origin of rice showed relatively little diversity compared with the ones obtained from other parts of the world, suggesting migration from a common region of origin. The tropical japonica lines can be a great source of parental diversification for hybrid development after confirming the presence of widely compatible genes.
Journal Article
Novel star-shaped fractal antenna for multiband applications
2017
Fractals have unique properties such as self-similarity and space-filling. The use of fractal geometry in antenna design provides a good method for achieving the desired miniaturization, multi-band, and wideband properties. In this communication, novel fractal geometry is proposed based on which a multiband antenna is designed. The proposed antenna has fractal patches which are shaped as different iterations of an eight-pointed star. The multiband behavior is in the frequency range from 4.50 to 17.00 GHz. The proposed antenna is designed on a dielectric substrate Roggers RO4003 lossy with a dielectric constant of εr = 3.55. The antenna has applications in commercial and military communication system.
Journal Article