Biology subjects

Banerjee, S.

Publications and source records attributed to Banerjee, S..

At least 253 records · Page 14Linked to original sources

bioRxiv2019

The anti-leishmanial activity of Spergulin-A involves P2X7R-P38MAPK axis

Current drugs are inadequate for the treatment of visceral leishmaniasis an immunosuppressive ailment caused by Leishmania donovani. Regrettably, there is no plant-origin antileishmanial drug present. P2X7R is constitutively present on macrophage surfaces and can be a putative therapeutic target in intra-macrophage pathogens with function attributes towards inflammation, host cell apoptosis, altered redox, and phagolysosomal maturation by activating p38MAPK. Here we demonstrated that the initial interaction of Spergulin-A (SpA), a triterpenoid saponin with RAW 264.7 macrophages was mediated through P2X7R involving the signaling cascade intermediates Ca++, P38MAPK, and NF-{kappa}{beta}. P38MAPK involvement is shown to have specific and firm importance in leishmanial killing with increased NF-{kappa}Bp65. Phago-lysosomal maturation by Sp A also campaigns for another contribution of P2X7R. In vivo evaluation of the anti-leishmanial activity of Sp A was monitored through expression analyses of P2X7R, P38MAPK, and NF-{kappa}{beta} in murine spleen and bone-marrow macrophages and advocated Sp A of being a natural compound of leishmanicidal functions which acted through the P2X7R-P38MAPK axis. SIGNIFICANCE OR IMPORTANCEPreciously, this manuscript demonstrated previously unreported initial interaction of Spergulin-A, a triterpenoid saponin isolated from Glinus oppositifolius with macrophages through P2X7R involving the signaling cascade intermediates Ca++, P38MAPK, and NF-{kappa}{beta}. Signaling interaction is shown to have specific importance in the leishmanial killing. Phago-lysosomal maturation also campaigns for another contribution of P2X7R. In vivo evaluation was monitored through P2X7R, P38MAPK, and NF-{kappa}{beta} in murine spleen and bone-marrow macrophages and advocated Sp A of being a natural compound of leishmanicidal functions which acted through the P2X7R-P38MAPK axis. The result supports that Spergulin-A can provide new lead molecules for the development of alternative drugs against VL. We feel very strongly that this work can be very interesting as it describes a detailed evaluation of leishmanicidal effect by Sp A and thus has every potential to attract a lot of workers especially in the fields of pharmacology, drug development, immunology, as well as parasitology.

molecular biology↗

bioRxiv2019

Natural hybridization reveals incompatible alleles that cause melanoma in swordtail fish

The establishment of reproductive barriers between populations is the key process that fuels the evolution of new species. A genetic framework for this process was proposed over 80 years ago, which posits "incompatible" interactions between genes that result in reduced survival or reproduction in hybrids. Despite this foundational work, progress has been slow in identifying individual genes that underlie hybrid incompatibilities, with only a handful known to date. Here, we use a combination of approaches to precisely map the genes that drive the development of a melanoma incompatibility in swordtail fish hybrids. We find that one of the genes involved in this incompatibility also causes melanoma in hybrids between distantly related species. Moreover, we show that this melanoma reduces survival in the wild, likely due to progressive degradation of the fin. Together, this work represents only the second case where the genes underlying a vertebrate hybrid incompatibility have been identified and provides the first glimpse into the action of these genes in natural hybrid populations. One sentence summaryUsing a combination of mapping approaches, we identify interacting genes that lead to melanoma in hybrids and characterize their effects in natural hybrid populations.

evolutionary biology↗

bioRxiv2019

Leishmania infection triggers hepcidin-mediated proteasomal degradation of Nramp1 resulting in increased phagolysosomal iron availability

Natural resistance associated macrophage protein 1 (Nramp1) was discovered as a genetic determinant of resistance against multiple intracellular pathogens, including Leishmania. It encodes a transmembrane protein of the phago-endosomal vesicles, where it functions as an iron transporter. But how Nramp1 expression is regulated in an infected macrophage is unknown. Its role in controlling iron availability to the intracellular pathogens and in determining the final outcome of an infection also remains to be fully deciphered. Here we report that Nramp1 protein abundance undergoes temporal changes in Leishmania major infected macrophages. At 12 hours post infection, there was drastic lowering of Nramp1 level accompanied by increased phagolysosomal iron availability and enhanced parasite growth. Leishmania infection-induced downregulation of Nramp1 was found to be caused by ubiquitin-proteasome degradation pathway. In fact, blocking of Nramp1 degradation with proteasome inhibitor resulted in depletion of phagolysosomal iron pool with significant reduction in the number of intracellular parasites. Further, we uncovered that this degradation process is mediated by the iron regulatory peptide hormone hepcidin that binds to Nramp1. Interestingly, Nramp1 protein level was restored to normalcy after 30 hours of infection with a concomitant drop in the phagolysosomal iron level, which is suggestive of a host counter defense strategy to deprive the pathogen of this essential micronutrient. Taken together, our study implicates Nramp1 as a central player in the host-pathogen battle for iron. It also unravels Nramp1 as a novel partner for hepcidin. The hitherto unidentified hepcidin-Nramp1 axis may have a broader role in regulating macrophage iron homeostasis.\n\nImportanceLeishmania parasites are the causative agents of a group of neglected tropical diseases called leishmaniasis. They reside within the phagolysosomes of mammalian macrophages. Since iron is an essential micronutrient for survival and virulence, intracellular Leishmania must acquire it from the tightly regulated macrophage iron pool. How this challenging task is accomplished remains a fundamental question in Leishmania biology. We report here that Leishmania major infection caused ubiquitin-proteasome-mediated degradation of natural resistance associated macrophage protein 1 (Nramp1). Nramp1 being an iron exporter at the phago-endosomal membrane, its degradation resulted in increased phagolysosomal iron availability thereby stimulating parasite growth. We also uncovered that Nramp1 degradation is controlled by the iron regulatory peptide hormone hepcidin. Interestingly, at a later stage of infection, Nramp1 protein level was restored to normalcy with simultaneous depletion of phagolysosomal iron. Collectively, our study implicates Nramp1 as a central player in the host-pathogen struggle for acquiring iron.

cell biology↗

bioRxiv2019

Age associated microbiome modulation and its association with systemic inflammation in a Rhesus Macaque Model

BackgroundAs the individual ages, the immune system decreases in activity while chronic systemic inflammation increases. The microbiome is also affected by age, decreasing in beneficial microbes while increasing in pathogenic, inflammation inducing microbes with corresponding changes in their metabolic profile. While aging is known to affect both, links between the two have been hard to uncover. MethodsFour young (age 3-6 years) and 12 old (age>18 years) Rhesus macaques were recruited for the study. PBMCs and plasma were collected to investigate immune cell subsets by flow cytometry and plasma cytokines by bead based multiplex cytokine analysis respectively. Stool samples were collected by ileal loop for microbiome analysis by shotgun metagenomics and serum, gut microbial lysate and microbe-free fecal extract was used to determine metabolomics by mass-spectrometry. ResultsOur aging NHP model recaptured many of the features of the age-associated immune alterations, with increased inflammation and alterations in immune cells subsets with lower number of CD4 T cells and a trend of age associated alterations in maturation subsets in older animals with lower naive and higher central memory CD4 T cells. Older animals showed a significantly different microbiome from young animals with lower abundance of Firmicutes and higher Archaeal and Proteobacterial species. Correlation analysis showed a link between microbes in older animals with systemic inflammation. Analysis of metabolites in the serum and feces showed significant differences between specific metabolites between young and older animals that can influence age-associated morbidities. ConclusionThese data support the age associated alterations in microbiome profile and its association with persistent systemic inflammation and metabolome changes. Further mechanistic studies are needed to understand the relationship between inflammation and microbiome. Nevertheless, this NHP model recapitulates human age associated changes in immune, inflammatory and microbiome profiles and can be useful for designing future studies targeting microbiome modulations in aging.

microbiology↗

bioRxiv2019

Distinct modes of cell competition are governed by entropic and energetic properties of mixed cell populations

How cells with different genetic makeups compete in tissues is an outstanding question in developmental biology and cancer research. Studies in recent years have revealed that cell competition can either be driven by short-range biochemical signalling or by long-range mechanical stresses in the tissue. To date, cell competition has generally been characterised at the population-scale, leaving the single-cell level mechanisms of competition elusive. Here, we use high time-resolution experimental data to construct a multi-scale agent-based model for epithelial cell competition, and use it to gain a conceptual understanding of the cellular factors that governs competition in cell populations within tissues. We find that a key determinant of mechanical competition is the difference in homeostatic density between winners and losers, while differences in growth rates and tissue organisation do not affect competition end-result. In contrast, the outcome and kinetics of biochemical competition is strongly influenced by local tissue organisation. Indeed, when loser cells are homogenously mixed with winners at the onset of competition, they are eradicated; however, when they are spatially separated, winner and loser cells coexist for long times. These findings suggest distinct biophysical origins for mechanical and biochemical modes of cell competition.

biophysics↗

bioRxiv2019

Systems-level analysis of monocyte responses in inflammatory bowel disease identifies IL-10 and IL-1 cytokine networks that regulate IL-23

BACKGROUND & AIMSDysregulated immune responses are the cause of inflammatory bowel diseases. Studies in both mice and humans suggest a central role of IL-23 producing mononuclear phagocytes in disease pathogenesis. Mechanistic insights into the regulation of IL-23 are prerequisite for select IL-23 targeting therapies as part of personalized medicine. METHODSWe performed transcriptomic analysis to investigate IL-23 expression in human mononuclear phagocytes and peripheral blood mononuclear cells. We investigated the regulation of IL-23 expression and used single-cell RNA-sequencing to derive a transcriptomic signature of hyper-inflammatory monocytes. Using gene network correlation analysis, we deconvolve this signature into components associated with homeostasis and inflammation in patient biopsy samples. RESULTSWe characterized monocyte subsets of healthy individuals and patients with inflammatory bowel disease that express IL-23. We identified auto- and paracrine sensing of IL-1/IL-1{beta} and IL-10 as key cytokines that control IL-23-producing monocytes. Whereas Mendelian genetic defects in IL-10 receptor signalling induced IL-23 secretion, uptake of whole bacteria induced IL-23 production via acquired IL-10 signalling resistance. We found a transcriptional signature of IL-23-producing inflammatory monocytes that predicted both disease and resistance to anti-TNF therapy and differentiated that from an IL-23-associated lymphocyte differentiation signature that was present in homeostasis and in disease. CONCLUSIONOur work identifies IL-10 and IL-1 as critical regulators of monocyte IL-23 production. We differentiate homeostatic IL-23 production from hyper-inflammation-associated IL-23 production in patients with severe ulcerating active Crohns disease and anti-TNF treatment non-responsiveness. Altogether, we identify subgroups of patients with inflammatory bowel disease that might benefit from IL-23p19 and/or IL-1/IL-1{beta}-targeting therapies upstream of IL-23. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/719492v2_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@16598faorg.highwire.dtl.DTLVardef@11e5116org.highwire.dtl.DTLVardef@15d831borg.highwire.dtl.DTLVardef@4a697e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2019

Two C-terminal sequence variations determine differential neurotoxicity between human and mouse α-synuclein

-Synuclein (aSyn) aggregation is thought to play a central role in neurodegenerative disorders termed synucleinopathies, including Parkinsons disease (PD). Mouse aSyn contains a threonine residue at position 53 that mimics the human familial PD substitution A53T, yet in contrast to A53T patients, mice show no evidence of aSyn neuropathology even after aging. Here we studied the neurotoxicity of human A53T, mouse aSyn, and various human-mouse chimeras in cellular and in vivo models as well as their biochemical properties relevant to aSyn pathobiology. We report that mouse aSyn is less neurotoxic than the human A53T variant as a result of inhibitory effects of two C-terminal amino acid substitutions on membrane-induced aSyn aggregation and aSyn-mediated vesicle permeabilization. Our findings highlight the importance of membrane-induced self-assembly in aSyn neurotoxicity and suggest that inhibiting this process by targeting the C-terminal domain could slow neurodegeneration in PD and other synucleinopathy disorders.

neuroscience↗

bioRxiv2019

Long non-coding RNA GAS5 acts as proliferation brakes in CD133+ cells responsible for tumor recurrence

Presence of quiescent, therapy evasive population often described as cancer stem cells (CSC) or tumor initiating cells (TIC) is often attributed to extreme metastasis and tumor recurrence. This population is typically enriched in a tumor as a result of microenvironment or chemotherapy induced stress. The TIC population adapts to this stress by turning on cell cycle arrest programs that is a \"fail-safe\" mechanism to prevent expansion of malignant cells to prevent further injury. Upon removal of the \"stress\" conditions, these cells restart their cell cycle and regain their proliferative nature thereby resulting in tumor relapse. Growth Arrest Specific 5 (GAS5) is a long-noncoding RNA that plays a vital role in this process. In pancreatic cancer, CD133+ population is a typical representation of the TIC population that is responsible for tumor relapse. In this study, we show for the first time that emergence of CD133+ population coincides with upregulation of GAS5, that reprograms the cell cycle to slow proliferation by inhibiting GR mediated cell cycle control. The CD133+ population further routed metabolites like glucose to shunt pathways like pentose phosphate pathway, that were predominantly biosynthetic in spite of being quiescent in nature but did not use it immediately for nucleic acid synthesis. Upon inhibiting GAS5, these cells were released from their growth arrest and restarted the nucleic acid synthesis and proliferation. Our study thus showed that GAS5 acts as a molecular switch for regulating quiescence and growth arrest in CD133+ population, that is responsible for aggressive biology of pancreatic tumors.

cancer biology↗

bioRxiv2019

Dysregulated RasGRP1 expression promotes autoimmunity

RasGRP1 is a Ras guanine nucleotide exchange factor, and an essential regulator of lymphocyte receptor signaling. In mice, Rasgrp1 deletion results in defective T lymphocyte development. RASGRP1-deficient patients suffer from immune deficiency, and the RASGRP1 gene has been linked to autoimmunity. However, how RasGRP1 levels are regulated, and if RasGRP1 dosage alterations contribute to autoimmunity remains unknown. We demonstrate that diminished Rasgrp1 expression caused defective T lymphocyte selection in C57BL/6 mice, and that the severity of inflammatory disease inversely correlates with Rasgrp1 expression levels. In patients with autoimmunity, active inflammation correlated with decreased RASGRP1 levels in CD4+ T cells. By analyzing H3K27 acetylation profiles in human T cells, we identified a RASGRP1 enhancer that harbors autoimmunity-associated SNPs. CRISPR-Cas9 disruption of this enhancer caused lower RasGRP1 expression, and decreased binding of RUNX1 and CBFB transcription factors. Analyzing patients with autoimmunity, we detected reduced RUNX1 expression in CD4+ T cells. Lastly, we mechanistically link RUNX1 to transcriptional regulation of RASGRP1 to reveal a key circuit regulating RasGRP1 expression, which is vital to prevent inflammatory disease.

immunology↗

bioRxiv2019

Gut microbial dysbiosis in individuals with Sjögren’s disease

PurposeTo evaluate the gut microbiome in individuals with Sjogrens and correlate bacterial profiles to dry eye (DE) measures.\n\nMethodsProspective case series of individuals with confirmed (n=13) and unconfirmed (n=8) Sjogrens (n=21; total cases) as compared to healthy controls (n=10). Stool was analyzed by 16S pyrosequencing and associations between bacterial classes and DE symptoms and signs were examined.\n\nResultsFirmicutes was the dominant phylum in the gut, comprising 40-60% of all phyla. On a phyla level, subjects with Sjogrens (confirmed and unconfirmed) had depletion of Firmicutes (1.1- fold) and an expansion of Proteobacteria (3.0-fold), Actinobacteria (1.7-fold), and Bacteroidetes (1.3-fold) compared to controls. Shannons diversity index showed no differences between groups with respect to the numbers of different operational taxonomic units (OTUs) encountered (diversity) and the instances these unique OTUs were sampled (evenness). On the other hand, Faiths phylogenetic diversity showed increased diversity in cases vs controls, which reached significance when comparing confirmed Sjogrens and controls (13.57 {+/-} 0.89 and 10.96 {+/-} 0.76, p=0.02). Using Principle Co-ordinate Analysis, qualitative differences in microbial composition were noted with differential clustering of cases and controls. Dimensionality reduction and clustering of complex microbial data further showed differences between the three groups, with regard to microbial composition, association and clustering. Finally, differences in certain classes of bacteria correlated with DE symptoms and signs.\n\nConclusionsIndividuals with Sjogrens have gut microbiome alterations as compared to healthy controls. Certain classes of bacteria were associated with DE measures.

physiology↗

bioRxiv2019

Mechanosensitive junction remodelling promotes robust epithelial morphogenesis

Morphogenesis of epithelial tissues requires tight spatiotemporal coordination of cell shape changes. In vivo, many tissue-scale shape changes are driven by pulsatile contractions of intercellular junctions, which are rectified to produce irreversible deformations. The functional role of this pulsatory ratchet and its mechanistic basis remain unknown. Here we combine theory and biophysical experiments to show that mechanosensitive tension remodelling of epithelial cell junctions promotes robust epithelial shape changes via ratcheting. Using optogenetic control of actomyosin contractility, we find that epithelial junctions show elastic behaviour under low contractile stress, returning to their original lengths after contraction, but undergo irreversible deformation under higher magnitudes of contractile stress. Existing vertex-based models for the epithelium are unable to capture these results, with cell junctions displaying purely elastic or fluid-like behaviours, depending on the choice of model parameters. To describe the experimental results, we propose a modified vertex model with two essential ingredients for junction mechanics: thresholded tension remodelling and continuous strain relaxation. First, a critical strain threshold for tension remodelling triggers irreversible junction length changes for sufficiently strong contractions, making the system robust to small fluctuations in contractile activity. Second, continuous strain relaxation allows for mechanical memory removal, enabling frequency-dependent modulation of cell shape changes via mechanical ratcheting. Taken together, the combination of mechanosensitive tension remodelling and junctional strain relaxation provides a robust mechanism for large-scale morphogenesis.

biophysics↗

bioRxiv2019

DYRK2 activates heat shock factor 1 promoting resistance to proteotoxic stress and tumour growth in triple-negative breast cancer

To survive aneuploidy-induced proteotoxic stress, cancer cells activate the proteotoxic-stress response pathway, which is controlled by heat shock factor 1 (HSF1). This pathway supports cancer initiation, cancer progression and chemoresistance and thus is an attractive target. As developing HSF1 inhibitors is challenging, the identification and targeting of upstream regulators of HSF1 presents a tractable alternative strategy. Here we demonstrate that in triple negative breast cancer (TNBC) cells, the dual-specificity tyrosine-regulated kinase 2 (DYRK2) phosphorylates HSF1, promoting its nuclear stability and transcriptional activity. Thus, DYRK2 depletion reduces HSF1 activity and sensitises TNBC cells to proteotoxic stress. Importantly, in tumours from TNBC patients, DYRK2 levels positively correlate with active HSF1 and associates with poor prognosis, suggesting that DYRK2 could be promoting TNBC. In agreement with this, DYRK2 depletion reduces tumour growth in a TNBC xenograft model. These findings identify DYRK2 as both, a key modulator of the HSF1 transcriptional program, and a potential therapeutic target.

cancer biology↗

bioRxiv2019

RhoA mediates epithelial cell shape changes via mechanosensitive endocytosis

Morphogenetic movements require tight spatiotemporal control over cell-cell junction lengths. Contractile forces, acting at adherens junctions, alter cell-cell contact lengths in a cyclic fashion as a mechanical ratchet. Pulsatile RhoA activity is thought to drive ratcheting through acute periods of junction contraction followed by stabilization. Currently, we lack a mechanistic understanding of if and how RhoA activity governs junction length and subsequent cell shape within epithelia. In this study we use optogenetics to exogenously control RhoA activity in model Caco-2 epithelium. We find that at short timescales, RhoA activation drives reversible junction contraction. Sustained RhoA activity drives irreversible junction shortening but the amount of shortening saturates for a single pulse. To capture these data, we develop a vertex model modified to include strain-dependent junction length and tension remodeling. We find that, to account for experimental data, tension remodeling requires a strain-dependent threshold. Our model predicts that temporal structuring of RhoA activity allows for subsequent tension remodeling events to overcome the limited shortening within a single pulse and this is confirmed by our experimental data. We find that RhoA-mediated junction remodeling requires activities of formin and dynamin, indicating the closely inter-connected activities of contractility, E-cadherin clustering, and endocytosis. Junction length is therefore regulated by the coordinated action of RhoA-mediated contractility, membrane trafficking, and adhesion receptor remodeling. Altogether these data provide insights into the underlying molecular and biophysical mechanisms of RhoA-mediated regulation of epithelial cell shape.

cell biology↗

bioRxiv2019

Lipid membranes trigger misfolding and self-assembly of amyloid β 42 protein into aggregates

The assembly of polypeptides and proteins into nanoscale aggregates is a phenomenon observed in a vast majority of proteins. Importantly, aggregation of amyloid {beta} (A{beta}) proteins is considered as a major cause for the development of Alzheimers disease. The process depends on various conditions and typical test-tube experiments require high protein concentration that complicates the translation of results obtained in vitro to understanding the aggregation process in vivo. Here we demonstrate that A{beta}42 monomers at the membrane bilayer are capable of self-assembling into aggregates at physiologically low concentrations, and the membrane in this aggregation process plays a role of a catalyst. We applied all-atom molecular dynamics to demonstrate that the interaction with the membrane surface dramatically changes the conformation of A{beta}42 protein. As a result, the misfolded A{beta}42 rapidly assembles into dimers, trimers and tetramers, so the on-surface aggregation is the mechanism by which amyloid oligomers are produced and spread.

neuroscience↗

bioRxiv2019

Universal surface-to-volume scaling and aspect ratio homeostasis in rod-shaped bacteria

Rod-shaped bacterial cells can readily adapt their lengths and widths in response to environmental changes. While many recent studies have focused on the mechanisms underlying bacterial cell size control, it remains largely unknown how the coupling between cell length and width results in robust control of rod-like bacterial shapes. In this study we uncover a universal surface-to-volume scaling relation in Escherichia coli and other rod-shaped bacteria, resulting from the preservation of cell aspect ratio. To explain the mechanistic origin of aspect-ratio control, we propose a quantitative model for the coupling between bacterial cell elongation and the accumulation of an essential division protein, FtsZ. This model reveals a mechanism for why bacterial aspect ratio is independent of cell size and growth conditions, and predicts cell morphological changes in response to nutrient perturbations, antibiotics, MreB or FtsZ depletion, in quantitative agreement with experimental data.

biophysics↗

bioRxiv2019

Cell-type specific mechanical response and actomyosin dynamics in the developing Drosophila retina

During organogenesis, different cell types need to work together to induce functional multicellular structures. To study this process, we made use of the genetically tractable fly retina, with a focus on the mechanisms that coordinate morphogenesis between the different epithelial cell types that make up the optical lens. Our work shows that these epithelial cells present contractile apical-medial MyosinII meshworks, which control the apical area and junctional geometry of these cells during lens development. Our study also suggests that MyosinII meshworks drive cell shape changes in response to external forces, and thus they mediate part of the biomechanical coupling that takes place between these cells. Importantly, our work, including mathematical modelling of forces and material stiffness during lens development, raises the possibility that increased cell stiffness acts as a mechanism for limiting this mechanical coupling. We propose this might be required in complex tissues, where different cell types undergo concurrent morphogenesis and where averaging out of forces across cells could compromise individual cell apical geometry and thereby organ function.

developmental biology↗

bioRxiv2019

Biological Evaluation of Molecules of the azaBINOL Class as Antiviral Agents: Specific Inhibition of HIV-1 RNase H Activity by 7-Isopropoxy-8-(naphth-1-yl)quinoline

Inspired by bioactive biaryl-containing natural products found in plants and the marine environment, a series of synthetic compounds belonging to the azaBINOL chiral ligand family was evaluated for antiviral activity against HIV-1. Testing of 39 unique azaBINOLs in a singleround infectivity assay resulted in the identification of three promising antiviral compounds, including 7-isopropoxy-8-(naphth-1-yl)quinoline (azaBINOL B#24), which exhibited low-micromolar activity. The active compounds and several close structural analogues were further tested against three different HIV-1 envelope pseudotyped viruses as well as in a full-virus replication system (EASY-HIT). Mode-of-action studies using a time-of-addition assay indicated that azaBINOL B#24 acts after viral entry but before viral assembly and budding. HIV-1 reverse transcriptase (RT) assays that individually test for polymerase and RNase H activity were used to demonstrate that B#24 inhibits RNase H activity, most likely allosterically. Further binding analysis using bio-layer interferometry (BLI) showed that B#24 interacts with HIV-1 RT in a highly specific manner. These results indicate that azaBINOL B#24 is a potentially viable, novel lead for the development of new HIV-1 RNase H inhibitors. Furthermore, this study demonstrates that the survey of libraries of synthetic compounds, designed purely with the goal of facilitating chemical synthesis in mind, may yield unexpected and selective drug leads for the development of new antiviral agents.

pharmacology and toxicology↗

bioRxiv2019

Targeting tumor intrinsic metabolic node in pancreatic cancer causes tumor regression, remodels extracellular matrix and sensitizes to anti-PD1 therapy.

Pancreatic ductal adenocarcinoma (PDAC) is considered to be a highly immunosuppressive and heterogenous neoplasm. Despite improved knowledge regarding the genetic background of the tumor and better understanding of the tumor microenvironment, immune checkpoint inhibitor therapy (targeting CTLA-4, PD-1, PD-L1) has not been very successful against PDAC.\n\nThe robust desmoplastic stroma, along with an extensive extracellular matrix (ECM) that is rich in hyaluronan, plays an integral role in this immune evasion. Hexosamine biosynthesis pathway (HBP), a shunt pathway of glycolysis, is a metabolic node in cancer cells that can promote survival pathways on one hand and influence the hyaluronan synthesis in the ECM on the other. The rate-limiting enzyme of the pathway, glutamine-fructose amidotransferase (GFAT1), uses glutamine and fructose 6-phosphate to eventually synthesize UDP-GlcNAc.\n\nIn the current manuscript, we target this glutamine-utilizing enzyme by a small molecule glutamine analog (6-diazo-5-oxo-L-norleucine or DON). Our results show that DON decreases the self-renewal potential and metastatic ability of tumor cell. Further, treatment with DON results in a decrease in hyaluronan and collagen in the tumor microenvironment, leading to an extensive remodeling of the ECM. this in turn, increases CD8+ cytotoxic T-cells infiltration, and makes the tumors tumors more amenable and sensitive to anti-PD1 therapy.

cancer biology↗