Biology subjects

Rashid, R.

Publications and source records attributed to Rashid, R..

12 recordsLinked to original sources

bioRxiv2026

Cellular nucleic acid-binding protein (CNBP) dependent cytokine programming shapes host defense against Plasmodium infection

During blood-stage Plasmodium infection, effective immune control hinges on the IL12{beta}-IFN-{gamma} axis, yet how this pathway is transcriptionally tuned in vivo remains incompletely defined. Innate sensing of parasite-derived ligands by pattern-recognition receptors, including Toll like receptors, in dendritic cells and macrophages induces IL-12{beta} production that drives IFN-{gamma} mediated control of infection. Emerging evidence implicates cellular nucleic acid-binding protein (CNBP), a zinc-finger transcriptional regulator, in control of IL12{beta} gene expression in myeloid cells exposed to bacterial and viral infections. Here, we defined the contribution of CNBP in cytokine-driven immunity to Plasmodium infection including both P. falciparum (the major cause of malaria), as well as P. chabaudi and P. berghei ANKA, two rodent species that model human disease. Upon exposure to Plasmodium-infected erythrocytes, CNBP rapidly translocated to the nucleus in mouse and human dendritic cells, bound IL12{beta} promoter, and was required for optimal IL12{beta} induction. Genetic ablation of CNBP in mice and siRNA knockdown of CNBP in human monocyte-derived dendritic cells markedly reduced IL12{beta} production and downstream IFN-{gamma} responses, while TNF- and several other innate cytokines were largely unaffected. In vivo, hematopoietic-specific deletion of CNBP (using vav-iCre; Cnbpfl/fl) resulted in elevated peak parasitemia, impaired parasite clearance, and relapse after initial resolution. Consistent with these outcomes, spleens from mice lacking CNBP in hematopoietic cells exhibited reduced inflammatory remodeling, altered T-cell composition, and transcriptional reprogramming characterized by selective regulation of IL12{beta}-IFN-{gamma} transcripts alongside upregulation of distinct cytotoxic genes. Paradoxically, mice lacking CNBP in hematopoietic cells showed delayed mortality in the lethal infection model, underscoring its context-dependent contributions to host protection and inflammatory pathology. Collectively, these findings position CNBP as a pivotal modulator of the IL12{beta}-IFN-{gamma} axis during malaria, extending its functional repertoire beyond microbial contexts, with potential as a therapeutic target to fine-tune immune responses for enhanced protection with limited immunopathology. Author summaryMalaria remains one of the worlds deadliest infectious diseases, caused by the protozoan Plasmodium that trigger complex immune responses in infected hosts. Effective host defense requires a tightly regulated inflammatory response: too weak and the parasite proliferates unchecked; too strong and the host suffers harmful immunopathology. Central to this balance is the IL12{beta}-IFN-{gamma} signaling axis. In this study, we investigated the role of a transcriptional regulator, known as Cellular Nucleic acid-Binding Protein (CNBP), in shaping the immune response against the Plasmodium parasite. We found that CNBP rapidly responds to parasite exposure, translocates to the nucleus and drives IL12{beta} production in innate immune cells, and promotes downstream IFN-{gamma} driven adaptive immune responses. Mice lacking CNBP in hematopoietic stem cells exhibited changes in transcription of key inflammatory genes; markedly reduced systemic IL12{beta} and IFN-{gamma}, leading to significantly elevated peripheral blood parasitemia and altered immune cell composition. Paradoxically, the absence of CNBP delayed mortality in a lethal infection model and reduced inflammatory responses that are associated with cytokine storm-mediated immunopathology. These findings identify CNBP as a key regulator that fine-tunes protective immunity and inflammatory pathology during malaria, highlighting its potential as a therapeutic target to optimize host defense while limiting harmful inflammation.

immunology↗

bioRxiv2024

Toxin-glycolipid interactions measured by imaging surface plasmon resonance on artificial membranes predicts diffusion behavior and lipid dependence of binding to cells

Membrane-protein interactions mediate cellular invasion by toxins, and are thought to involve organized plasma membrane lipid domains, often containing glycolipids, other sphingolipids, and/or cholesterol. Here, we characterize an isolated glycolipid-interacting domain of the tetanus toxin heavy chain (Hc) as a fluorescently labelled peptide, TeNT46, and describe its membrane dynamics and binding characteristics on artificial bilayers and cellular membranes. We show that this novel ganglioside-interacting probe TeNT46 retains the glycolipid binding preferences of the parent toxin, using imaging-SPR (iSPR) on a micro-patterned hybrid bilayer surface. On live cell membranes, using fluorescence correlation spectroscopic (FCS) diffusion measurements to compare TeNT46 to the well-studied GM1-binding toxin CTxB, we find that both probes display ordered domain-binding characteristics, but distinct cholesterol and sphingolipid dependencies. Strikingly, the contrasting lipid requirements of TeNT46 from those of CTxB in cells are predicted by their iSPR binding preferences on hybrid synthetic membranes. Based on the combined findings from iSPR and FCS, we propose a model for toxin-membrane interaction whereby a unique lipid constellation determines optimum binding for each probe independently of lateral confinement, which is more generally imposed by cholesterol. Our resulting understanding of the specific lipid requirements of these toxin targets and their dynamics in cell membranes could be important for the future design of preventive membrane-based nano-decoys and cell-delivery tools.

cell biology↗

bioRxiv2023

2D and 3D multiplexed subcellular profiling of nuclear instability in human cancer

Nuclear atypia, including altered nuclear size, contour, and chromatin organization, is ubiquitous in cancer cells. Atypical primary nuclei and micronuclei can rupture during interphase; however, the frequency, causes, and consequences of nuclear rupture are unknown in most cancers. We demonstrate that nuclear envelope rupture is surprisingly common in many human cancers, particularly glioblastoma. Using highly-multiplexed 2D and super-resolution 3D-imaging of glioblastoma tissues and patient-derived xenografts and cells, we link primary nuclear rupture with reduced lamin A/C and micronuclear rupture with reduced lamin B1. Moreover, ruptured glioblastoma cells activate cGAS-STING-signaling involved in innate immunity. We observe that local patterning of cell states influences tumor spatial organization and is linked to both lamin expression and rupture frequency, with neural-progenitor-cell-like states exhibiting the lowest lamin A/C levels and greatest susceptibility to primary nuclear rupture. Our study reveals that nuclear instability is a core feature of cancer, and links nuclear integrity, cell state, and immune signaling.

cancer biology↗

bioRxiv2022

Lung tumor-infiltrating Treg have divergent transcriptional profiles and function linked to checkpoint blockade response

Regulatory T cells (Treg) are conventionally viewed to suppress endogenous and therapyinduced anti-tumor immunity; however, their role in modulating responses to immune checkpoint blockade (ICB) is unclear. In this study, we integrated single-cell RNAseq/TCRseq of >73,000 tumor-infiltrating Treg (TIL-Treg) from anti-PD-1-treated and treatment naive non-small cell lung cancers (NSCLC) with single cell analysis of tumor-associated antigen (TAA)-specific Treg derived from a murine tumor model. We identified 10 subsets of human TIL-Treg, most of which have high concordance with murine TIL-Treg subsets. Notably, one subset selectively expresses high levels of OX40 and GITR, whose engangement by cognate ligand mediated proliferative programs and NF-kB activation, as well as multiple genes involved in Treg suppression, in particular LAG3. Functionally, the OX40hiGITRhi subset in the most highly suppressive ex vivo and Treg expression of OX40, GITR and LAG3, correlated with resistance to PD-1 blockade. Surprisingly, in the murine tumor model, we found that virtually all TIL-Treg expressing T cell receptors that are specific for TAA fully develop a distinct Th1-like signature over a two-week period after entry into the tumor, down-regulating FoxP3 and up-regulating expression of TBX21 (Tbet), IFN{gamma} and certain pro-inflammatory granzymes. Application of a gene score from the murine TAA-specific Th1-like Treg subset to the human single-cell dataset revealed a highly analogous subcluster that was enriched in anti-PD-1 responding tumors. These findings demonstrate that TIL-Treg partition into multiple distinct transcriptionally-defined subsets with potentially opposing effects on ICB-induced anti-tumor immunity and suggest that TAA-specific TIL-Treg may positively contribute to anti-tumor responses. One-Sentence SummaryWe define 10 subsets of lung cancer-infiltrating regulatory T cells, one of which is highly suppressive and enriched in anti-PD-1 non-responders and the other is Th1-like and is enriched in PD-1 responders.

immunology↗

bioRxiv2022

IL-33-induced neutrophilic inflammation and NETosis underlie rhinovirus-triggered exacerbations of asthma

Rhinovirus-induced neutrophil extracellular traps (NETs) contribute to acute asthma exacerbations, however the molecular factors that trigger NETosis in this context remain ill-defined. Here, we sought to implicate a role for IL-33, an epithelial cell-derived alarmin rapidly released in response to infection. In mice with chronic experimental asthma (CEA), but not naive controls, rhinovirus inoculation induced an early (1 day post infection; dpi) inflammatory response dominated by neutrophils, neutrophil-associated cytokines (IL-1, IL-1{beta}, CXCL1) and NETosis, followed by a later, type-2 inflammatory phase (3-7 dpi), characterized by eosinophils, elevated IL-4 levels, and goblet cell hyperplasia. Notably, both phases were ablated by HpARI (Heligmosomoides polygyrus Alarmin Release Inhibitor), which blocks IL-33 release and signalling. Instillation of exogenous IL-33 recapitulated the rhinovirus-induced early phase, including the increased presence of NETs in the airway mucosa, in a PAD4-dependent manner. Ex vivo IL-33-stimulated neutrophils from mice with CEA, but not naive mice, underwent NETosis, and produced greater amounts of IL-1/{beta}, IL-4, and IL-5. In nasal samples from rhinovirus-infected people with asthma, but not healthy controls, IL-33 levels correlated with neutrophil elastase and dsDNA. Our findings suggest that IL-33 blockade ameliorates the severity of an asthma exacerbation by attenuating neutrophil recruitment and the downstream generation of NETs.

immunology↗

bioRxiv2022

Depleting cationic lipids involved in antimicrobial resistance drives adaptive lipid remodeling in Enterococcus faecalis

The bacterial cell membrane is an interface for cell envelope synthesis, protein secretion, virulence factor assembly and a target for host cationic antimicrobial peptides (CAMPs). To resist CAMP killing, several Gram-positive pathogens encode the multiple peptide resistance factor (MprF) enzyme that covalently attaches cationic amino acids to anionic phospholipids in the cell membrane. While E. faecalis encodes two mprF paralogs, MprF2 plays a dominant role in conferring resistance to killing by the CAMP human {beta}-defensin 2 (hBD-2) in E. faecalis strain OG1RF. The goal of the current study is to understand the broader lipidomic and functional roles of E. faecalis mprF. We analyzed the lipid profiles of parental wild type and mprF mutant strains and show that while {triangleup}mprF2 and {triangleup}mprF1 {triangleup}mprF2 mutants completely lacked cationic lysyl-phosphatidylglycerol (L-PG), the {triangleup}mprF1 mutant synthesized [~]70% of L-PG compared to the parent. Unexpectedly, we also observed a significant reduction of PG in {triangleup}mprF2 and {triangleup}mprF1 {triangleup}mprF2. In the mprF mutants, particularly {triangleup}mprF1 {triangleup}mprF2, the decrease in L-PG and PG is compensated by an increase in the phosphorus-containing lipid, GPDGDAG, and D-ala-GPDGDAG. These changes were accompanied by a downregulation of de novo fatty acid biosynthesis and an accumulation of long-chain acyl-acyl carrier proteins (long-chain acyl-ACPs), suggesting that the suppression of fatty acid biosynthesis was mediated by the transcriptional repressor FabT. Growth in chemically defined media lacking fatty acids revealed severe growth defects in the {triangleup}mprF1 {triangleup}mprF2 mutant strain, but not the single mutants, which was partially rescued through supplementation with palmitic and stearic acids. Changes in lipid homeostasis correlated with lower membrane fluidity, impaired protein secretion, and increased biofilm formation in both {triangleup}mprF2 and {triangleup}mprF1 {triangleup}mprF2, compared to wild type and {triangleup}mprF1. Collectively, our findings reveal a previously unappreciated role for mprF in global lipid regulation and cellular physiology, which could facilitate the development of novel therapeutics targeting MprF. Significance StatementThe cell membrane plays a pivotal role in protecting bacteria against external threats, such as antibiotics. Cationic phospholipids such as lysyl-phosphatidyglycerol (L-PG) resist the action of cationic antimicrobial peptides through electrostatic repulsion. Here we demonstrate that L-PG depletion has several unexpected consequences in Enterococcus faecalis, including a reduction of phosphatidylglycerol (PG), enrichment of a phosphorus-containing lipid, reduced fatty acid synthesis accompanied by an accumulation of long-chain acyl-acyl carrier proteins (long chain acyl-ACPs), lower membrane fluidity, and impaired secretion. These changes are not deleterious to the organism as long as exogenous fatty acids are available for uptake from the culture medium. Our findings suggest an adaptive mechanism involving compensatory changes across the entire lipidome upon removal of a single phospholipid modification. Such adaptations must be considered when devising antimicrobial strategies that target membrane lipids.

microbiology↗

bioRxiv2022

Green synthesis of ZnO nanoparticles using Cocos nucifera leaf extract: Characterization, antimicrobial, antioxidant, and photocatalytic activity

Zinc oxide nanoparticles (ZnO NPs) have been successfully prepared using Cocos nucifera leaf extract and investigated with their antimicrobial, antioxidant, and photocatalytic activity. The structural, compositional, and morphological properties of the NPs were recorded and studied systematically to confirm the synthesis. The aqueous suspension of NPs showed a UV-Vis. absorption maxima of 370 nm indicating primarily its formation. The XRD analysis identified the NPs with hexagonal wurtzite structure with an average particle size of 16.6 nm. The FTIR analysis identified some biomolecules and functional groups in the leaf extract as responsible for the encapsulation and stabilization of ZnO NPs. The EDX analysis showed the desired elemental compositions in the material. A flower-shaped morphology of ZnO NPs was observed by SEM with a grain size of around 15 nm. The optical properties of the NPs were studied by UV-Vis spectroscopy and the band gap was calculated as 3.37 eV. The prepared ZnO NPs have demonstrated antimicrobial activity against T. harzianum and S. aureus with a ZOI (zone of inhibition) of 14 and 10 mm, respectively. The photocatalytic behavior of ZnO NPs showed absorbance degradation at around 640 nm and discolored methylene blue dye after one hour with a degradation maximum of 84.29 %. Thus, the prepared ZnO NPs could be used potentially in antibiotic development, pharmaceutical industries, and as photocatalysts.

biochemistry↗

bioRxiv2022

Single Cell Spatial Analysis Reveals the Topology of Immunomodulatory Purinergic Signaling in Glioblastoma

Glioblastoma develops an immunosuppressive microenvironment that fosters tumorigenesis and resistance to current therapeutic strategies. Here we use multiplexed tissue imaging and single-cell RNA-sequencing to characterize the composition, spatial organization, and clinical significance of extracellular purinergic signaling in glioblastoma. We show that glioblastoma exhibit strong expression of CD39 and CD73 ectoenzymes, correlating with increased adenosine levels. Microglia are the predominant source of CD39, while CD73 is principally expressed by tumor cells, particularly in tumors with amplification of EGFR and astrocyte-like differentiation. Spatially-resolved single-cell analyses demonstrate strong spatial correlation between tumor CD73 and microglial CD39, and that their spatial proximity is associated with poor clinical outcomes. Together, this data reveals that tumor CD73 expression correlates with tumor genotype, lineage differentiation, and functional states, and that core purine regulatory enzymes expressed by neoplastic and tumor-associated myeloid cells interact to promote a distinctive adenosine-rich signaling niche and immunosuppressive microenvironment potentially amenable to therapeutic targeting.

cancer biology↗

bioRxiv2021

The composition and function of Enterococcus faecalismembrane vesicles

Membrane vesicles (MVs) contribute to various biological processes in bacteria, including virulence factor delivery, host immune evasion, and cross-species communication. MVs are frequently being discharged from the surface of both Gram-negative and Gram-positive bacteria during growth. In some Gram-positive bacteria, genes affecting MV biogenesis have been identified, but the mechanism of MV formation is unknown. In Enterococcus faecalis, a causative agent of life-threatening bacteraemia and endocarditis, neither mechanisms of MV formation nor their role in virulence has been examined. Since MVs of many bacterial species are implicated in host-pathogen interactions, biofilm formation, horizontal gene transfer, and virulence factor secretion in other species, we sought to identify, describe, and functionally characterize MVs from E. faecalis. Here we show that E. faecalis releases MVs that possess unique lipid and protein profiles, distinct from the intact cell membrane, and are enriched in lipoproteins. MVs of E. faecalis are specifically enriched in unsaturated lipids that might provide membrane flexibility to enable MV formation, providing the first insights into the mechanism of MV formation in this Gram-positive organism.

microbiology↗

bioRxiv2020

Interpretative guides for interacting with tissue atlas and digital pathology data using the Minerva browser

The recent development of highly multiplexed tissue imaging promises to substantially accelerate research into basic biology and human disease. Concurrently, histopathology in a clinical setting is undergoing a rapid transition to digital methods. Online tissue atlases involving highly multiplexed images of research and clinical specimens will soon join genomics as a systematic source of information on the molecular basis of disease and therapeutic response. However, even with recent advances in machine learning, experience with anatomic pathology shows that there is no immediate substitute for expert visual review, annotation, and description of tissue images. In this perspective we review the ecosystem of software available for analysis of tissue images and identify a need for interactive guides or "digital docents" that allow experts to help make complex images intelligible. We illustrate this idea using Minerva software and discuss how interactive image guides are being integrated into multi-omic browsers for effective dissemination of atlas data.

scientific communication and education↗

bioRxiv2019

Highly multiplexed immunofluorescence images and single-cell data of immune markers in tonsil and lung cancer

In this data descriptor, we document a dataset of multiplexed immunofluorescence images and derived single-cell measurements of immune lineage and other markers in formaldehyde-fixed and paraffin-embedded (FFPE) human tonsil and lung cancer tissue. We used tissue cyclic immunofluorescence (t-CyCIF) to generate fluorescence images which we artifact corrected using the BaSiC tool, stitched and registered using the ASHLAR algorithm, and segmented using ilastik software and MATLAB. We extracted single-cell features from these images using HistoCAT software. The resulting dataset can be visualized using image browsers and analyzed using high-dimensional, single-cell methods. This dataset is a valuable resource for biological discovery of the immune system in normal and diseased states as well as for the development of multiplexed image analysis and viewing tools.\n\nMETADATA SUMMARY\n\nO_TBL View this table:\norg.highwire.dtl.DTLVardef@6edf3eorg.highwire.dtl.DTLVardef@1026e07org.highwire.dtl.DTLVardef@85a7baorg.highwire.dtl.DTLVardef@c6d7e5org.highwire.dtl.DTLVardef@87fccf_HPS_FORMAT_FIGEXP M_TBL C_TBL

cancer biology↗

bioRxiv2018

Comparing the metabolic fates of BALB/c mice maintained on cafeteria-style diets with differential nutritive values

Cafeteria (CAF) diet-fed rodents are shown to provide a robust model of metabolic syndrome and human obesity. The carbohydrate/fat-rich food-items provided to the CAF-diet-model more closely approximate the ultra-processed human diet. However, most of the previous studies applied the commercially available rodent chow-diet for the comparative analyses and labeled it as a healthy-diet. The presented work aims to extend the knowledge on CAF-diet model by exposing the mice to human foods with different nutritional values. Our major goal was to study the metabolic fates of mice maintained on human food-items, which depending upon on their macronutrient compositions are categorized as healthy or unhealthy. BALB/c mice were randomly allocated to one of the three dietary intervention groups, standard chow diet; high-sugar/high-fat-cafeteria (HSHF-CAF) diet; or low-sugar/low-fat-cafeteria (LSLF-CAF) diet, for 5 weeks. The differences in multiple metabolic parameters (including food-/energy /macronutrient-intake, body-weight gain rate, organ-to-body weight ratios, plasma lipid profiles, adipocyte physiology, lipid deposition in metabolic tissues and ectopic fat storage in heart and kidney) were compared among the three intervention groups. We did not observe hyperphagia in mice maintained on CAF-diets. Nonetheless, the CAF-diet-fed mice displayed increased weight-gain-rate, adiposity, and adipocyte hypertrophy when compared to the chow-fed mice. However, the mice maintained on the two cafeteria-style diets displayed similar metabolic profiles, with HSHF-CAF-group displaying slightly higher weight-gain-rate. The HSHF-CAF-and LSLF-CAF-diet induced comparable adiposity in BALB/c mice. Further studies, with longer dietary intervention periods, are required to elucidate the effects of differential CAF-diets on the metabolic health of mice.

biochemistry↗