Biology subjects

Chatterjee, A.

Publications and source records attributed to Chatterjee, A..

At least 91 records · Page 5Linked to original sources

bioRxiv2022

Safety and biodistribution of NanoligomersTM targeting SARS-CoV-2 genome for treatment of COVID-19

As the world braces to enter its third year in the coronavirus disease 2019 (COVID-19) pandemic, the need for accessible and effective antiviral therapeutics continues to be felt globally. The recent surge of Omicron variant cases has demonstrated that vaccination and prevention alone cannot quell the spread of highly transmissible variants. A safe and nontoxic therapeutic with an adaptable design to respond to the emergence of new variants is critical for transitioning to treatment of COVID-19 as an endemic disease. Here, we present a novel compound, called SBCoV202, that specifically and tightly binds the translation initiation site of RNA-dependent RNA polymerase within the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome, inhibiting viral replication. SBCoV202 is a Nanoligomer, a molecule that includes peptide nucleic acid sequences capable of binding viral RNA with single-base-pair specificity to accurately target the viral genome. The compound has been shown to be safe and nontoxic in mice, with favorable biodistribution, and has shown efficacy against SARS-CoV-2 in vitro. Safety and biodistribution were assessed after three separate administration methods, namely intranasal, intravenous, and intraperitoneal. Safety studies showed the Nanoligomer caused no outward distress, immunogenicity, or organ tissue damage, measured through observation of behavior and body weight, serum levels of cytokines, and histopathology of fixed tissue, respectively. SBCoV202 was evenly biodistributed throughout the body, with most tissues measuring Nanoligomer concentrations well above the compound KD of 3.37 nM. In addition to favorable availability to organs such as the lungs, lymph nodes, liver, and spleen, the compound circulated through the blood and was rapidly cleared through the renal and urinary systems. The favorable biodistribution and lack of immunogenicity and toxicity set Nanoligomers apart from other antisense therapies, while the adaptability of the nucleic acid sequence of Nanoligomers provides a defense against future emergence of drug resistance, making these molecules an attractive potential treatment for COVID-19.

bioengineering↗

bioRxiv2022

Reversing Radiation-Induced Immunosuppression Using a New Therapeutic Modality

Radiation-induced immune suppression poses significant health challenges for millions of patients undergoing cancer chemotherapy and radiotherapy treatment, and astronauts and space tourists travelling to outer space. While a limited number of recombinant protein therapies, such a Sargramostim, are approved for accelerating hematologic recovery, the pronounced role of granulocyte-macrophage colony-stimulating factor (GM-CSF or CSF2) as a proinflammatory cytokine poses additional challenges in creating immune dysfunction towards pathogenic autoimmune diseases. Here we present an approach to high-throughput drug-discovery, target validation, and lead molecule identification using nucleic acid-based molecules. These Nanoligomer molecules are rationally designed using a bioinformatics and an artificial intelligence (AI)-based ranking method and synthesized as a single-modality combining 6-different design elements to up- or downregulate gene expression of target gene, resulting in elevated or diminished protein expression of intended target. This method additionally alters related gene network targets ultimately resulting in pathway modulation. This approach was used to perturb and identify the most effective upstream regulators and canonical pathways for therapeutic intervention to reverse radiation-induced immunosuppression. The lead Nanoligomer identified in a screen of human donor derived peripheral blood mononuclear cells (PBMCs) upregulated Erythropoietin (EPO) and showed the greatest reversal of radiation induced cytokine changes. It was further tested in vivo in a mouse radiation-model with low-dose (3 mg/kg) intraperitoneal administration and was shown to regulate gene expression of epo in lung tissue as well as counter immune suppression. These results point to the broader applicability of our approach towards drug-discovery, and potential for further investigation of lead molecule as reversible gene therapy to treat adverse health outcomes induced by radiation exposure.

genomics↗

bioRxiv2022

Evolution of Delta variant by non-Spike signature co-appearing mutations: trailblazer of COVID-19 disease outcome

The high transmissibility and infectivity of a SARS-CoV-2 variant is usually ascribed to the Spike mutations, while emerging non-spike mutations might be a serious threat to the current Spike-recombinant vaccines. In addition to mutations in structural Spike glycoprotein, rapid accumulation of mutations across non-structural genes is leading to continuous virus evolution, altering its pathogenicity. We performed whole genome sequencing of SARS-CoV-2 positive samples collected from different clinical groups from eastern India, during the second pandemic wave (April-May, 2021). In addition to the several common spike mutations in Delta variant, two mutually explicit signature constellations of non-spike co-appearing mutations were identified, driving symptomatic and asymptomatic infections. We attempted to correlate these unique signatures of non-Spike co-appearing mutations to COVID-19 disease outcome. Results revealed that the Delta strains harboring a unique constellation of 9 non-spike co-appearing mutations could be the wheeler and dealer of symptomatic infection, even post vaccination. The strains predominantly driving asymptomatic infection possessed 7 non-spike co-appearing mutations, which were mutually exclusive in contrast to the set of mutations causing symptomatic disease. Phylodynamic analysis depicted high probability of emergence of these unique sub-clusters within India, with subsequent spread worldwide. Interestingly, some mutations of this signature were selected in Omicron and IHU variants, which suggest that gradual accumulation of such co-existing mutations may lead to emergence of more "vaccine-evading variants" in future. Hence, unfaltering genome sequencing and tracking of non-Spike mutations might be significant in formulation of any future vaccines against emerging SARS-CoV-2 variants that might evade the current vaccine-induced immunity.

genomics↗

bioRxiv2022

Virus-assisted directed evolution of enhanced suppressor tRNAs in mammalian cells

Site-specific incorporation of unnatural amino acids (Uaas) in living cells relies on engineered aminoacyl-tRNA synthetase/tRNA pairs borrowed from a distant domain of life. Such heterologous suppressor tRNAs often show poor intrinsic activity, presumably due to the failure to optimally interact with a non-native translation system. This limitation can be addressed in E. coli using directed evolution. However, no suitable selection system is currently available to do the same in mammalian cells. Here we report virus-assisted directed evolution of tRNAs (VADER) in mammalian cells, which employs a double-sieve selection scheme to facilitate single-step enrichment of active-yet-orthogonal tRNA mutants from naive libraries. Using VADER, we developed improved mutants of M. mazei pyrrolysyl-tRNA, the most popular Uaa mutagenesis platform in eukaryotes. We also show that the higher activity of the most efficient mutants is specific for mammalian cells, alluding to an improved interaction with the unique mammalian translation system.

synthetic biology↗

bioRxiv2021

A facile platform to engineer E. coli tyrosyl-tRNA synthetase adds new chemistries to the eukaryotic genetic code, including a phosphotyrosine mimic

The E. coli tyrosyl-tRNA synthetase (EcTyrRS)/tRNAEcTyr pair offers an attractive platform to genetically encode new noncanonical amino acids (ncAA) in eukaryotes. However, challenges associated with a eukaryotic selection system, which is needed for its engineering, has impeded its success in the past. Recently, we showed that EcTyrRS can be engineered using a facile E. coli based selection system, in a strain where the endogenous tyrosyl pair has been substituted with an archaeal counterpart. However, a significant cross-reactivity between the UAG-suppressing tRNACUAEcTyr and the bacterial glutaminyl-tRNA synthetase limited the scope of this strategy, preventing the selection of moderately active EcTyrRS mutants. Here we report an engineered tRNACUAEcTyr that overcomes this cross-reactivity. Optimized selection systems using this tRNA enabled efficient enrichment of both strongly and weakly active ncAA-selective EcTyrRS mutants. We also developed a wide-dynamic range (WiDR) antibiotic selection to further enhance the activities of the weaker first-generation EcTyrRS mutants. We demonstrated the utility of our platform by developing several new EcTyrRS mutants that efficiently incorporate useful ncAAs in mammalian cells, including photo-affinity probes, bioconjugation handles, and a non-hydrolyzable mimic of phosphotyrosine.

synthetic biology↗

bioRxiv2021

Substrate stiffness modulates integrin α5 expression and ECM-associated gene expression in fibroblasts

Biomaterials, like polydimethylsiloxane (PDMS), are soft, biocompatible, and tuneable, which makes them useful to delineate specific substrate factors that regulate the complex landscape of cell-substrate interactions. We used a commercial formulation of PDMS to fabricate substrates with moduli 40 kPa, 300 kPa, and 1.5 MPa, and cultured HMF3S fibroblasts on them. Gene expression analysis was performed by RT-PCR and Western blotting. Cellular and nuclear morphologies were analyzed using confocal imaging, and MMP-2 and MMP-9 activities were determined with gelatin zymography. Results, comparing mechanotransduction on PDMS substrates with control petridishes, show that substrate stiffness modulates cell morphologies and proliferations. Cell nuclei were rounded on compliant substrates and correlated with increased tubulin expression. Proliferations were higher on stiffer substrates with cell cycle arrest on softer substrates. Integrin 5 expression decreased on lower stiffness substrates, and correlated with inefficient TGF-{beta} activation. Changes to the activated state of the fibroblast on higher stiffness substrates were linked to altered TGF-{beta} secretion. Collagen I, collagen III, and MMP-2 expression levels were lower on compliant PDMS substrates as compared to stiffer ones; there was little MMP-9 activity on substrates. These results demonstrate critical feedback mechanisms between substrate stiffness and ECM regulation by fibroblasts which is highly relevant in diseases like tissue fibrosis.

bioengineering↗

bioRxiv2021

Effector loss drives adaptation of Pseudomonas syringae pv. actinidiae to Actinidia arguta

A pandemic isolate of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) has devastated kiwifruit orchards growing cultivars of Actinidia chinensis. In contrast, A. arguta (kiwiberry) is resistant to Psa3. This resistance is mediated via effector-triggered immunity, as demonstrated by induction of the hypersensitive response in infected A. arguta leaves, observed by microscopy and quantified by ion-leakage assays. Isolates of Psa3 that cause disease in A. arguta have been isolated and analyzed, revealing a 49 kb deletion in the exchangeable effector locus (EEL). This natural EEL-mutant isolate and strains with synthetic knockouts of the EEL were more virulent in A. arguta plantlets than wild-type Psa3. Screening of a complete library of Psa3 effector knockout strains identified increased growth in planta for knockouts of four effectors - AvrRpm1a, HopF1c, HopZ5a, and the EEL effector HopAW1a - suggesting a resistance response in A. arguta. Hypersensitive response (HR) assays indicate that three of these effectors trigger a host species-specific HR. A Psa3 strain with all four effectors knocked out escaped host recognition, but a cumulative increase in bacterial pathogenicity and virulence was not observed. These avirulence effectors can be used in turn to identify the first cognate resistance genes in Actinidia for breeding durable resistance into future kiwifruit cultivars.

plant biology↗

bioRxiv2021

Locus-Specific DNA Methylation Editing in Mammalian Cells using a CRISPR-Based System

DNA methylation is a key epigenetic modification implicated in the pathogenesis of numerous human diseases, including cancer development and metastasis. Gene promoter methylation changes are widely associated with transcriptional deregulation and disease progression. The advent of CRISPR-based technologies has provided a powerful toolkit for locus-specific manipulation of the epigenome. Here, we describe a comprehensive global workflow for the design and application of a dCas9-SunTag-based tool for editing a DNA methylation locus in human melanoma cells, alongside protocols for downstream techniques used to evaluate subsequent methylation and gene expression changes in methylation-edited cells. Using transient system delivery, we demonstrate both highly efficacious methylation and demethylation of the EBF3 promoter, a putative epigenetic driver of melanoma metastasis, achieving up to 304.00% gain of methylation and 99.99% relative demethylation, respectively. Further, we employ a novel, targeted screening approach to confirm minimal off-target activity and high on-target specificity of our editing sys-tem within our target locus.

molecular biology↗

bioRxiv2021

Homology Modelling, In Silico Prediction And Characterization Of Cytochrome c oxidase In Cyprinus carpio And Tubifex tubifex And Molecular Docking Studies Between The Modelled Protein And Three Commonly Used Surfactants Sodium Dodecyl Sulphate, Cetylpyridinium Chloride And Sodium Laureth Sulphate

The purpose of this work is to evaluate the homology modeling, in silico prediction, and characterisation of Cytochrome c oxidase from Cyprinus carpio and Tubifex tubifex, as well as molecular docking experiments between the modelled protein and three frequently used surfactants. Using the template crystal structure of bovine heart Cytochrome c oxidase, homology modeling of Cytochrome c oxidase (Subunit 2) of Cyprinus carpio (Accession # P24985) and Cytochrome c oxidase (Subunit 1) of Tubifex tubifex (Accession # Q7YAA6) was conducted. The model structure was improved further with 3Drefine, and the final 3D structure was verified with PROCHEK and ERRATA. The physiochemical, as well as the stereochemical parameters of the modelled protein, were evaluated using various tools like ExPASys ProtParam, Hydropathy Analysis and EMBOSS pepwheel. The projected model was then docked with toxic ligands, Sodium dodecyl sulfate (SDS), Cetylpyridinium chloride (CPC), and Sodium laureth sulfate (SLES), whose 3D structures were obtained from the Uniprot database. CPC interacted best with Cytochrome c oxidase subunit 2 of Cyprinus carpio and Cytochrome c oxidase subunit 1 of Tubifex tubifex, according to our findings. Furthermore, in the case of all surfactants, hydrophobic interactions with the active site amino acid residues of the modelled protein were observed to be more common than hydrogen bonds and salt bridges. Molecular simulation studies exhibited that the surfactants alter the structural flexibility of the predicted proteins. Hence it may be inferred that the surfactants might alter the structure and dynamics of Cytochrome c oxidase of both worm and fish.

bioinformatics↗

bioRxiv2021

Loss of GdpP function in Staphylococcus aureus leads to β-lactam tolerance and enhanced evolution of β-lactam resistance

SynopsisO_ST_ABSBackgroundC_ST_ABSWe previously reported the presence of mutations in gdpP among Staphylococcus aureus strains that were obtained by serial passaging in {beta}-lactam drugs. gdpP codes for a phosphodiesterase that cleaves cyclic-di-AMP (CDA), a newly discovered second messenger. ObjectivesWe sought to identify the role of gdpP in {beta}-lactam resistance of S. aureus. MethodsCDA concentrations in bacterial cytosol were measured through mass-spectrometric analysis. gdpP deletion mutagenesis and their complemented strains were created in clinically relevant S. aureus strains to characterize its function. ResultsgdpP associated mutations among passaged strains were identified to cause loss of phosphodiesterase function, leading to increased CDA accumulation in the bacterial cytosol. Deletion of gdpP led to an enhanced ability of the bacteria to withstand a {beta}-lactam challenge (two to three log increase in bacterial colony forming units) by promoting tolerance without enhancing MICs of {beta}-lactam antibiotics. Our results demonstrate that increased drug tolerance due to loss of GdpP function can provide a selective advantage in acquisition of high-level {beta}-lactam resistance and could lead to {beta}-lactam treatment failure of S. aureus infections. ConclusionsLoss of GdpP function increases tolerance to {beta}-lactams that can lead to its therapy failure and can permit {beta}-lactam resistance to occur more readily.

microbiology↗

bioRxiv2021

Cystinosin deficient rats recapitulate the phenotype of nephropathic cystinosis

BackgroundThe lysosomal storage disease cystinosis is caused by mutations in CTNS, encoding a cystine transporter, and in its severest form leads to proximal tubule dysfunction followed by kidney failure. Patients receive the drug-based therapy cysteamine from diagnosis. However, despite long-term treatment, cysteamine only slows the progression of end-stage renal disease and a kidney transplant is inevitable. Pre-clinical testing in cystinotic rodents is required to evaluate new therapies; however, the current models are sub-optimal. To solve this problem we generated a new cystinotic rat model. MethodsWe utilized CRISPR/Cas9-mediated gene editing to disrupt exon 3 of Ctns and measured various parameters over a 12-month time-course including blood and tissue cystine levels, urine and serum electrolytes, and analysed the histopathology and immunohistochemistry of the kidney. ResultsCtns-/- rats display hallmarks of cystinosis by 3-6 months of age as seen by a failure to thrive, excessive thirst and urination, cystine accumulation in tissues, corneal cystine crystals, a loss of Lrp2 in proximal tubules and immune cell infiltration. High levels of glucose, calcium, albumin and protein are excreted at 6-months of age, consistent with the onset of Fanconi syndrome, with a progressive diminution of urine urea and creatinine from 9-months of age, indicative of chronic kidney disease. The kidney histology and immunohistochemistry showed proximal tubule atrophy and glomerular damage as well as classic swan neck lesions. Overall, Ctns-/- rats show a disease progression that more faithfully recapitulates nephropathic cystinosis than existing rodent models. ConclusionsThe Ctns-/- rat provides an excellent new rodent model of nephropathic cystinosis that is ideally suited for conducting pre-clinical drug testing and a powerful tool to advance cystinosis research. Translational StatementGood animal models of disease are essential to perform pre-clinical testing of potential new drugs and therapies before they can progress to human clinical trials. Unfortunately, the cystinosis field has been hampered by a lack of suitable animal models that fully recapitulate the disease. We have overcome this by generating a new rat model of cystinosis by CRISPR-Cas9 gene editing. These rodents closely model the human condition in a time-frame that makes them an excellent model ideally suited for pre-clinical drug testing as well as being a powerful tool to advance cystinosis research.

physiology↗

bioRxiv2021

Genetic code expansion in the engineered organism Vmax X2: High yield and exceptional fidelity

We report that the recently introduced commercial strain of V. natriegens (Vmax X2) supports robust unnatural amino acid mutagenesis, generating exceptional yields of soluble protein containing up to 5 non-canonical -amino acids (ncAA). The isolated yields of ncAA-containing superfolder green fluorescent protein (sfGFP) expressed in Vmax X2 are up to 25-fold higher than those achieved using commercial expression strains (Top10 and BL21) and more than10-fold higher than those achieved using two different genomically recoded E. coli strains that lack endogenous UAG stop codons and release factor 1 and have been optimized for improved fitness and preferred growth temperature (C321.{Delta}A.opt and C321.{Delta}A.exp). In addition to higher yields of soluble protein, Vmax X2 cells also generate proteins with significantly lower levels of mis-incorporated natural -amino acids at the UAG-programmed position, especially in cases where the ncAA is an imperfect substrate for the chosen orthogonal aminoacyl tRNA synthetase (aaRS). This increase in fidelity implies that use of Vmax X2 cells as the expression host can obviate the need for time-consuming directed evolution experiments to improve specific activity of highly desirable but imperfect ncAA substrates.

synthetic biology↗

bioRxiv2021

Transcriptional reprogramming and constitutive PD-L1 expression in melanoma are associated with dedifferentiation and activation of interferon and tumor necrosis factor signaling pathways

Melanoma is the most aggressive type of skin cancer, with increasing incidence worldwide. Advances in targeted therapy and immunotherapy have improved the survival of melanoma patients experiencing recurrent disease, but unfortunately treatment resistance frequently reduces patient survival. Resistance to targeted therapy is associated with transcriptomic changes, and has also been shown to be accompanied by increased expression of programmed death ligand 1 (PD-L1), a potent inhibitor of immune response. Intrinsic upregulation of PD-L1 is associated with genome-wide DNA hypomethylation and widespread alterations in gene expression in melanoma cell lines. However, an in-depth analysis of the transcriptomic landscape of melanoma cells with intrinsically upregulated PD-L1 expression is lacking. To determine the transcriptomic landscape of intrinsically upregulated PD-L1 expression in melanoma, we investigated transcriptomes in melanomas with constitutive versus inducible PD-L1 expression (referred to as PD-L1CON and PD-L1IND). RNA-Seq analysis was performed on seven PD-L1CON melanoma cell lines and ten melanoma cell lines with low inducible PD-L1IND expression. We observed that PD-L1CON melanoma cells had a reprogrammed transcriptome with a characteristic pattern of dedifferentiated gene expression, together with active interferon (IFN) and tumor necrosis factor (TNF) signalling pathways. Furthermore, we identified key transcription factors that were also differentially expressed in PD-L1CON versus PD-L1IND melanoma cell lines. Overall, our studies describe transcriptomic reprogramming of melanomas with PD-L1CON expression. Simple SummaryMelanoma, an aggressive form of skin cancer, is frequently associated with drug resistance in the advanced stages. For instance, frequently resistance is observed to sequential treatment of melanoma with targeted therapy and immunotherapy. In this research, the authors investigated whether potential transcriptional mechanisms and pathways associated with PD-L1 protein expression could underlie targeted therapy drug resistance in melanoma. The authors found a PD-L1 expression transcriptional pattern underlies resistance to targeted therapy in a subgroup of melanomas. These melanomas were markedly dedifferentiated, as compared to melanomas that were not drug resistant. Understanding changes in transcription and molecular pathways that lead to drug resistance could allow researchers to develop interventions to prevent drug resistance from occurring in melanoma, which could also be relevant to other cancer types.

cancer biology↗

bioRxiv2021

Altered DNA methylation in ion transport and immune signalling genes is associated with severity in Pancreatic Ductal Adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the leading cancers worldwide and has a poor survival, with a relative five-year survival rate of only 8.5%. In this study we investigated epigenetic marksassociated with PDAC severity and prognosis, through studying alterations in DNA methylation patterns. MethodsDNA methylome for tumor and adjacent normal tissue samples from PDAC patients (n=7) were generated using Illumina 450K bead chips. Differentially methylated positions (DMPs) were identified with |delta beta| > 0.2 and p-value<0.01 by comparing tumors with the adjacent normal tissues. Validation of differential methylation and associated gene expression at selected genes was carried out in an independent cohort PDAC patient. ResultsWe identified 76 DMPs in PDAC patients that mapped to 43 genes. Among them, 44.7% (n=34) were hypo-methylated and 55.3% (n=42) were hyper-methylated DMPs in cancer samples. The trends of change in methylation at these 76 DMPs from well to moderate were like that from moderate to poorly differentiated cancer samples. The gradual trend in differential methylation was observed both in our cohort and the TCGA-PAAD cohort, suggesting methylation marks can serve as early indicators of disease pathology. Altered promoter methylation, which may affect gene expression, was observed for transcription regulators (BHLHE23, GSC2, FOXE1 and TWIST1), gated ion channels (KCNA6, and CACNB2), tumor suppressors (RASSF1, SPRED2, and NPY) and genes functioning in interferon signalling (SIGIRR, MX2, and OAS2). We also have compared the TCGA-PAAD dataset with normal pancreatic tissue data from GTEx V8 dataset leading to a confluent observation. ConclusionsWe reported the first study on methylome in PDAC tumors from patients in India. We identified altered DNA methylation associated with increasing severity in PDAC among some genes like SIGIRR, MX2 along with other previously reported loci. We also concluded a confluence in our observation when comparing the TCGA-PAAD dataset with GTEx V8 dataset.

cancer biology↗

bioRxiv2021

The mouse papillomavirus epigenetic signature is characterised by DNA hypermethylation after lesion regression

The {beta} genus of human papillomaviruses (HPVs) infect cutaneous epidermis. They contribute to the development of cutaneous squamous cell carcinoma (cSCC) in individuals with epidermodysplasia verruciformis, and increase susceptibility to UV-induced cSCC. This has been demonstrated in UV-exposed mice previously infected with mouse papillomavirus (MmuPV1). However, the mechanism by which {beta}-HPVs contribute to cSCC is unclear. We propose that viral infection leaves a DNA methylation signature following resolution of the active lesion that may contribute to increased susceptibility to UV-induced cSCC. To test this, we carried out Reduced Representation Bisulphite Sequencing on DNA from tail skin of mice with actively infected lesions, MmuPV1-infected then healed lesions (regressed infection), and mock-infected control mice. Genome-scale DNA methylation libraries were generated and analysed for differentially methylated regions throughout the genome, and for HPV sequences. We found that DNA of active lesions was not differentially methylated compared to matched control mice. In contrast, 834 differentially methylated fragments were identified in regressed lesions compared to mock-infected control skin. An analysis of MmuPV1 viral DNA demonstrated retention of viral DNA in some of the lesions that had regressed. Overall, the viral sequences identified showed over-representation of sequences from the E4 region. The DNA hypermethylation that we found in regressed MmuPV1 lesions may be a factor in the increased susceptibility of mice to UV-induced cSCC. AUTHOR SUMMARYPapillomavirus infections can be asymptomatic, can cause warts, and in some cases can lead to cancer. There is direct evidence for mouse papillomavirus infection resulting in increased susceptibility to UV-induced cutaneous squamous cell carcinoma in a mouse model. We propose that DNA methylation following viral infection may contribute to the increased susceptibility. We describe the DNA methylation landscape during an active infection with mouse papillomavirus and following regression of the lesion. We found that there were very few differentially methylated DNA fragments during active infection. In contrast, over 800 differentially methylated DNA fragments were identified following regression of the lesion. This is the first description of the genome-wide DNA methylation landscape for mouse papillomavirus, to our knowledge. The dramatic DNA hypermethylation that we observe following resolution of infection may contribute to a hit and run mechanism for the increased susceptibility to UV-induced cancer by papillomaviruses.

pathology↗

bioRxiv2021

Differences in Regional Grey Matter Volume Predict the Extent to which Openness influences Judgments of Beauty and Pleasantness of Interior Architectural Spaces

Hedonic evaluation of sensory objects varies from person to person. While this variability has been linked to differences in experience and personality traits, little is known about why stimuli lead to different evaluations in different people. We used linear mixed effect models to determine the extent to which the openness, contour, and ceiling height of interior architectural spaces influenced the beauty and pleasantness ratings of 18 participants. Then, by analyzing structural brain images acquired for the same group of participants we asked if any regional grey matter volume (rGMV) co-varied with these differences in the extent to which openness, contour and ceiling height influence beauty and pleasantness ratings. Voxel-based morphometry analysis revealed that the influence of openness on pleasantness ratings correlated with rGMV in the anterior prefrontal cortex (BA 10), and the influence of openness on beauty ratings correlated with rGMV in the temporal pole (BA 38) and posterior cingulate cortex (BA 31). There were no significant correlations involving contour or ceiling height. Our results suggest that regional variance in grey matter volume may play a role in the computation of hedonic valuation, and account for differences in the way people weigh certain attributes of interior architectural spaces.

neuroscience↗

bioRxiv2021

Fuzzy-Discernibility Matrix-based an Efficient Feature Selection Technique for Improved Motor-Imagery EEG Signal Classification

Brain activities, called brain rhythms, are the micro-level electrical signals (that is, Electroencephalogram or EEG) generated in our brain while we are performing a task. Even when we imagine a limb movement, it generates the same EEG signals called motor-imagery. Motor-imagery based Brain-computer Interface (BCI) provides a non-muscular means to connect the human brain with limbs through computer-based interpretations. The main aim of this paper is to find a suitable feature-set and a classifier to efficiently classify EEG signals into distinct motor-imagery brain-states. We propose to use sliding temporal window-based approaches for feature extraction from EEG and a mix-bagging classifier which is essentially a bagging-based ensemble of multiple types of learners for motor imagery EEG classification. We observe that mix-bagging with overlapping sliding window-based feature extraction achieves an accuracy of 91.43% on the BCI Competition II Dataset III. To reduce the feature size further, we use a fuzzy discernibility matrix that selects the most discriminative features instead of all the features. This additional feature selection strategy improves the classification accuracy to 92.14% and sets a new state-of-the art result on this dataset.

neuroscience↗

bioRxiv2021

Invariant Differential Expression Analysis Reveals Mechanism of Cancer Resistance to Cell Cycle Inhibitors

Retinoblastoma (RB) is a good model to study drug resistance to cell-cycle inhibitors because it is driven by mutations in the core components of cell-cycle, i.e, Rb gene. However, there is limited gene expression dataset in RB which has major reproducibility issues. We have developed invariant differential expression analysis (iDEA) that improves the state of the art in differential expression analysis (DEA). iDEA uses strong Boolean implication relationships in a large diverse human dataset GSE119087 (n = 25,955) to filter the noisy differentially expressed genes (DEGs). iDEA was applied to RB datasets and a gene signature was computed that led to prediction and mechanism of drug sensitivity. The prediction was confirmed using drugs-sensitive/resistant RB cell-lines and mouse xenograft models using CDC25 inhibitor NSC663284. iDEA improved reproducibility of differential expression across diverse retina/RB cohorts and RB cell-lines with different drug sensitivity (Y79/Weri vs NCC). Pathway analysis revealed WNT/{beta}-catenin involved in distinguishing drug sensitivity to CDC25 inhibitor NSC663284. NSC663284 inhibited tumour cell proliferation in mouse xenograft model containing Y79 cells indicating novel therapeutic option in RB. Invariant differentially expressed genes (iDEGs) are robustly associated with outcome in diverse cancer datasets and supports for a fundamental mechanism of drug resistance.

systems biology↗