Biology subjects

DasGupta, R.

Publications and source records attributed to DasGupta, R..

15 recordsLinked to original sources

bioRxiv2026

Dissecting Immune-Epithelial Interactions in Airway Infection at Single-Cell Resolution Using a Compartmentalised Microfluidic Device

Immune-epithelial interactions govern the initiation and progression of airway diseases, yet their heterogeneity is difficult to capture using existing in vitro models. Although conventional Transwell and lung-on-chip systems reproduce airway compartmentalisation and permit epithelial-immune interactions, they lack the spatial and analytical resolution needed to visualise dynamic immune behaviour during infection. Here, we present the "Single Cell resolved Airway-Immune Recruitment" (scAIR) platform designed to interrogate immune-epithelial interactions during airway infection. The scAIR device features a modular central chamber accommodating a Transwell insert with primary airway epithelial cells (AECs) pre-differentiated under air-liquid interface (ALI), flanked by immune compartments connected through a precision-patterned microchannel array. This architecture enables real-time single-cell imaging of immune cell migration while preserving epithelial physiology. The scAIR device coupled with a machine learning analysis (MLA) pipeline enables automated tracking and quantification of individual immune cell speed, direction, and behavioural heterogeneity. Using this platform, respiratory syncytial virus (RSV) infection is modelled to generate a type 1 inflammatory airway epithelium that drives neutrophil recruitment. TNF-alpha neutralisation with adalimumab reveals distinct migratory behaviours that are obscured by population-averaged measurements. This integrated platform quantifies airway immune responses during infection and therapeutic modulation, enabling mechanistic studies, drug evaluation, and precision modelling of airway inflammation.

bioengineering↗

bioRxiv2024

Identification of Cyclin L1 as a host factor regulating Hepatitis B Virus replication

Background & AimsUnderstanding the regulatory interactions between Hepatitis B virus (HBV) and human host factors is key to the development of next-generation host-directed antiviral therapies and achieving a functional HBV cure. In this study, we aimed to investigate HBV-induced alterations in host gene expression in primary human hepatocytes (PHH) to identify host-specific factors that are regulated and exploited by the virus for replication and survival. MethodsWe performed whole transcriptome sequencing (WTS) of HBV-infected PHH to identify host pathways that could potentially influence the HBV life cycle. RNA-interference-based validation of putative targets to evaluate the function of dysregulated candidate genes resulted in the identification of Cyclin L1 (CCNL1) as a key host factor. ResultsRNAi-knockdown of CCNL1 revealed that it is essential for HBV gene expression, including HBV-surface antigen (HBsAg). Mechanistically, we found that CCNL1 can phosphorylate the C-terminal domain (CTD) of RNA Polymerase II (RNAPII) at serine 2 (S2), likely to regulate HBV transcription. Furthermore, the knockdown of CCNL1 inhibited the binding of total and phospho- (Ser2-Ser5) RNAPII, pan-acetylated H3ac, and H3K27ac to HBV cccDNA, implicating its function in the regulation of cccDNA-dependent viral transcription. Finally, enhanced CCNL1 expression in chronic hepatitis B patients, as compared to those with resolved infection, underscores a functional link between this host factor and CHB. ConclusionOur data demonstrates that CCNL1 regulates HBV RNA transcription and replication by modulating RNAPII phosphorylation and activity, making it a potential host susceptibility factor for HBV. LAY SUMMARYHepatitis B requires human host cell factors and biological processes to establish an efficient infection. Identifying host factors that support and/or restrict HBV infection is essential for understanding the molecular basis of chronic HBV infection and for developing host-targeting anti-HBV drugs. Here, we report that CCNL1 can serve as a potential host susceptibility factor for HBV, as reduced CCNL1 function results in reduced viral replication and gene expression. Graphical SummaryGraphical summary, highlighting the approach and validation experiments. From whole transcriptomics analysis, we identified known HBV-host factors such as SRPK1, CDK1, NXF1 among others as well as new factors such as CCNL1. Employing various RNAi approaches and different cell models including primary human hepatocytes, we validated the role of CCNL1 during HBV infection cycle. Pull-down experiments followed by ChIP-PCR further showed a reduction in cccDNA-based transcription upon knockdown of CCNL1. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/619969v2_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@1ee9cd9org.highwire.dtl.DTLVardef@7bac2dorg.highwire.dtl.DTLVardef@164c3bborg.highwire.dtl.DTLVardef@6e497a_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

Single-cell and spatial atlas of steatotic liver-related hepatocellular carcinoma

Steatotic liver disease-related hepatocellular carcinoma (SLD-HCC) poses significant challenges in liver cancer management. Our current study investigates the tumor microenvironment (TME) of SLD-HCC using single-cell transcriptomic, proteomic and spatial transcriptomic analyses. We identified altered immune-related and lipid metabolism pathways, particularly in regulatory T cells (Tregs) and cancer-associated fibroblasts (CAFs) within the SLD-HCC microenvironment, suggesting distinct cellular adaptations to a high-fat TME and general immunosuppression. Cytometry by time-of-flight revealed a cold and immunosuppressive TME depleted with CD8+ T cells and enriched with Tregs, while spatial transcriptomics uncovered a unique spatial architecture with Treg/CAF clusters specifically located at the tumor margins in SLD-HCC. Crucially, we identified Treg-CAF interactions as a key mediator associated with lack of response to immunotherapy in SLD-HCC. Our findings highlight the intricate immune dynamics of SLD-HCC, indicating potential therapeutic targets to counteract immune evasion and restore anti-tumor immunity in SLD-HCC. HighlightsO_LIThe TME of SLD-HCC exhibits altered immune and lipid pathways C_LIO_LIImmunosuppressive SLD-HCC TME is depleted with CD8+ T cells and enriched with Tregs C_LIO_LISLD-HCC has a unique spatial architecture with Treg-CAF clusters at tumor margins C_LIO_LITreg-CAF interaction via TNFSF14-TNFRSF14 axis mediates immunotherapy resistance C_LI

immunology↗

bioRxiv2024

Enhanced NK cell proficiency in solid tumors through antigen-specific memory via NKG2C/A-HLA-E/ABC recruited to tumors by CXCR2

Natural killer (NK) cells have emerged as promising effectors in cancer immunotherapy due to their ability to recognize and eliminate tumor cells. To investigate the immunological memory and tumor reactivity of adaptive (a)NK cells in the context of desmoplastic tumors, we used human ovarian cancer as a model. Through in vitro culture systems resembling dendritic cell (DC)-mediated T cell activation, we demonstrated that aNK cells exhibit antigen-specific cytotoxic responses and memory generation towards ovarian tumor antigens. Furthermore, mature DCs presenting tumor-associated antigens induced the expansion of aNK cells, suggesting antigen-specific proliferation. Single-cell transcriptomics revealed a distinct genetic signature of aNK cells in tumor samples, characterized by a cytotoxic phenotype and interactions with myeloid cells, particularly DCs. The spatial analysis confirmed the intratumoral presence of aNK cells, with higher abundance in the tumor nest compared to conventional (c)NK cells. Functional assays demonstrated the cytotoxicity of expanded aNK cells against autologous ovarian tumors, accompanied by an activated receptor profile. Importantly, aNK cells displayed antigen-specific memory responses towards primary tumors, maintaining specificity over time. Blockade of NKG2C and HLA-E influenced aNK cell recall responses, indicating their roles in the adaptive NK cell immune memory. Additionally, CXCR2 was essential for efficient aNK cell migration toward tumors. These findings shed light on the therapeutic potential of aNK cells in ovarian cancer immunotherapy, highlighting their ability to develop immunological memory and effectively eradicate tumor cells.

immunology↗

bioRxiv2024

Deciphering the function of intrinsic and genomics-driven epigenetic heterogeneity in head and neck cancer progression with single-nucleus CUT&RUN

Interrogating regulatory epigenetic alterations during tumor progression at the resolution of single cells has remained an understudied area of research. Here we developed a highly sensitive single-nucleus CUT&RUN (snCUT&RUN) assay to profile histone modifications in isogenic primary, metastatic, and cisplatin-resistant head and neck squamous cell carcinoma (HNSCC) patient-derived tumor cell lines. We find that the epigenome can be involved in diverse modes to contribute towards HNSCC progression. First, we demonstrate that gene expression changes during HNSCC progression can be co-modulated by alterations in both copy number and chromatin activity, driving epigenetic rewiring of cell-states. Furthermore, intratumour epigenetic heterogeneity (ITeH) may predispose sub-clonal populations within the primary tumour to adapt to selective pressures and foster the acquisition of malignant characteristics. In conclusion, snCUT&RUN serves as a valuable addition to the existing toolkit of single-cell epigenomic assays and can be used to dissect the functionality of the epigenome during cancer progression.

cancer biology↗

bioRxiv2023

Breakage fusion bridge cycles drive high oncogene copy number, but not intratumoral genetic heterogeneity or rapid cancer genome change

Oncogene amplification is a major driver of cancer pathogenesis. Breakage fusion bridge (BFB) cycles, like extrachromosomal DNA (ecDNA), can lead to high copy numbers of oncogenes, but their impact on intratumoral heterogeneity, treatment response, and patient survival are not well understood due to difficulty in detecting them by DNA sequencing. We describe a novel algorithm that detects and reconstructs BFB amplifications using optical genome maps (OGMs), called OM2BFB. OM2BFB showed high precision (>93%) and recall (92%) in detecting BFB amplifications in cancer cell lines, PDX models and primary tumors. OM-based comparisons demonstrated that short-read BFB detection using our AmpliconSuite (AS) toolkit also achieved high precision, albeit with reduced sensitivity. We detected 371 BFB events using whole genome sequences from 2,557 primary tumors and cancer lines. BFB amplifications were preferentially found in cervical, head and neck, lung, and esophageal cancers, but rarely in brain cancers. BFB amplified genes show lower variance of gene expression, with fewer options for regulatory rewiring relative to ecDNA amplified genes. BFB positive (BFB (+)) tumors showed reduced heterogeneity of amplicon structures, and delayed onset of resistance, relative to ecDNA(+) tumors. EcDNA and BFB amplifications represent contrasting mechanisms to increase the copy numbers of oncogene with markedly different characteristics that suggest different routes for intervention.

cancer biology↗

bioRxiv2023

Deciphering the phenotypic heterogeneity and drug response in cancer cells using genome-wide activity and interaction of chromatin domains.

The effect of co-localization of genes in the topologically associated domains (TADs) and their activity as a regulatory unit in cancer samples and cells, together with drug-response, needs comprehensive analysis. Here, we analyzed the activity of TADs using cancer-cell transcriptomes along with chromatin-interaction and epigenome profiles to understand their relationship with drug-response. Our analysis of 819 cancer cell-line transcriptomes revealed that their response to multiple drugs was more correlated with the activity of individual TADs than genes. Applying our approach to 9014 cancer patients data (20 different cancer types) also revealed a higher association between survival and the activity of thousands of individual TADs in comparison to their genes. CRISPR-mediated knock-out of regulatory sites inside a TAD associated with cisplatin-response of oral cancer cells and discovery of primate-specific gain of synteny of genes within a TAD containing EGFR gene and its contribution towards cancer malignancy demonstrate greater utility of TAD-activity based analysis.

cancer biology↗

bioRxiv2021

A systematic benchmark of Nanopore long read RNA sequencing for transcript level analysis in human cell lines

The human genome contains more than 200,000 gene isoforms. However, different isoforms can be highly similar, and with an average length of 1.5kb remain difficult to study with short read sequencing. To systematically evaluate the ability to study the transcriptome at a resolution of individual isoforms we profiled 5 human cell lines with short read cDNA sequencing and Nanopore long read direct RNA, amplification-free direct cDNA, PCR-cDNA sequencing. The long read protocols showed a high level of consistency, with amplification-free RNA and cDNA sequencing being most similar. While short and long reads generated comparable gene expression estimates, they differed substantially for individual isoforms. We find that increased read length improves read-to-transcript assignment, identifies interactions between alternative promoters and splicing, enables the discovery of novel transcripts from repetitive regions, facilitates the quantification of full-length fusion isoforms and enables the simultaneous profiling of m6A RNA modifications when RNA is sequenced directly. Our study demonstrates the advantage of long read RNA sequencing and provides a comprehensive resource that will enable the development and benchmarking of computational methods for profiling complex transcriptional events at isoform-level resolution.

genomics↗

bioRxiv2020

Predicting heterogeneity in clone-specific therapeutic vulnerabilities using single-cell transcriptomic signatures

While understanding heterogeneity in molecular signatures across patients underpins precision oncology, there is increasing appreciation for taking intra-tumor heterogeneity into account. Single-cell RNA-seq (scRNA-seq) technologies have facilitated investigations into the role of intra-tumor transcriptomic heterogeneity (ITTH) in tumor biology and evolution, but their application to in silico models of drug response has not been explored. Based on large-scale analysis of cancer omics datasets, we highlight the utility of ITTH for predicting clinical outcomes. We then show that heterogeneous gene expression signatures obtained from scRNA-seq data can be accurately analyzed (80%) in a recommender system framework (CaDRReS-Sc) for in silico drug response prediction. Patient-derived cell lines capturing transcriptomic heterogeneity from primary and metastatic tumors were used as in vitro proxies for validating monotherapy predictions (Pearson r>0.6), as well as optimal drug combinations to target different subclonal populations (>10% improvement). Applying CaDRReS-Sc to the increasing number of publicly available tumor scRNA-seq datasets can serve as an in silico screen for further in vitro and in vivo drug repurposing studies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=191 SRC="FIGDIR/small/389676v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1aa5795org.highwire.dtl.DTLVardef@5c2323org.highwire.dtl.DTLVardef@106e074org.highwire.dtl.DTLVardef@7a0834_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LILarge-scale analysis to establish the impact of transcriptomic heterogeneity within tumors on clinical outcomes C_LIO_LICalibrated recommender system for drug response prediction based on single-cell RNA-seq data (CaDRReS-Sc) C_LIO_LIPrediction of drug response in patient-derived cell lines with transcriptomic heterogeneity C_LIO_LIIn silico identification of drug combinations that work based on clonal vulnerabilities C_LI

bioinformatics↗

bioRxiv2020

A Method to sort heterogenous cell populations based on migration in 2D and 3D environments

Whereas phenotypic assays such as Boyden chambers and wound healing assays can easily be employed to characterize the migratory potential of cells at the population level, few methods exist that can sort subpopulations of cells based on their migratory behaviour from an initial heterogeneous pool. In this paper, we present an approach to sort migratory cancer and immune cells based on their spontaneous migration in 2D and 3D microenvironments. Using this method, which is easy to implement and readily scalable, millions of live cells can be sorted based on their migratory characteristics and then subjected to downstream genomic, molecular and functional tests. We reveal that enrichment of the most migratory cytotoxic T lymphocytes yields a pool of cells with enhanced cytotoxicity against cancer cells. This new functional sorting method opens new avenues for the precise characterization of the mechanisms underlying hitherto unexplained heterogeneities in migratory phenotypes within a cell population, and for the targeted enrichment of the most potent migratory leukocytes in immunotherapies.

cell biology↗

bioRxiv2020

scRNA-seq reveals ACE2 and TMPRSS2 expression in TROP2+ Liver Progenitor Cells: Implications in COVID-19 associated Liver Dysfunction

The recent pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 was first reported in China (December 2019) and now prevalent in [~]170 countries across the globe. Entry of SARS-CoV-2 into mammalian cells require the binding of viral Spike (S) proteins to the ACE2 (angiotensin converting enzyme 2) receptor. Once entered the S protein is primed by a specialised serine protease, TMPRSS2 (Transmembrane Serine Protease 2) in the host cell. Importantly, beside respiratory symptoms, consistent with other common respiratory virus infection when patients become viraemic, a significant number of COVID-19 patients also develop liver comorbidities. We explored if specific target cell-type in the mammalian liver, could be implicated in disease pathophysiology other than the general deleterious response to cytokine storms. Here we employed single-cell RNA-seq (scRNA-seq) to survey the human liver and identified potentially implicated liver cell-type for viral ingress. We report the co-expression of ACE2 and TMPRSS2 in a TROP2+ liver progenitor population. Importantly, we fail to detect the expression of ACE2 in hepatocyte or any other liver (immune and stromal) cell types. These results indicated that in COVID-19 associated liver dysfunction and cell death, viral infection of TROP2+ progenitors in liver may significantly impaired liver regeneration and could lead to pathology. Highlights- EPCAM+ Liver progenitors co-express ACE2 and TMPRSS2 - ACE2 and TMPRSS2 expression is highest in TROP2high progenitors - ACE2 and TMPRSS2 cells express cholangiocyte biased fate markers - ACE2 and TMPRSS2 positive cells are absent in human fetal liver

genomics↗

bioRxiv2019

Data-driven inference of crosstalk in the tumor microenvironment

Signaling between cancer and nonmalignant (stromal) cells in the tumor microenvironment (TME) is key to tumorigenesis yet challenging to decipher from tumor transcriptomes. Here, we report an unbiased, data-driven approach to deconvolute bulk tumor transcriptomes and predict crosstalk between ligands and receptors on cancer and stromal cells in the TME of 20 solid tumor types. Our approach recovers known transcriptional hallmarks of cancer and stromal cells and is concordant with single-cell and immunohistochemistry data, underlining its robustness. Pan-cancer analysis reveals previously unrecognized features of cancer-stromal crosstalk. We find that autocrine cancer cell cross-talk varied between tissues but often converged on known cancer signaling pathways. In contrast, many stromal cross-talk interactions were highly conserved across tumor types. Interestingly, the immune checkpoint ligand PD-L1 was overexpressed in stromal rather than cancer cells across all tumor types. Moreover, we predicted and experimentally validated aberrant ligand and receptor expression in cancer cells of basal and luminal breast cancer, respectively. Collectively, our findings validate a data-driven method for tumor transcriptome deconvolution and establishes a new resource for hypothesis generation and downstream functional interrogation of the TME in tumorigenesis and disease progression.

cancer biology↗

bioRxiv2019

Single-cell analysis of EphA clustering phenotypes to probe cancer cell heterogeneity

Eph receptors, a family of receptor tyrosine kinases, play a crutial role in the assembly and maintenance of healthy tissues. Dysfunction in Eph signaling are causally and correlatively associated with cancer progression. In breast cancer cells, dysregulated Eph signaling has been largely linked to alterations in receptor clustering abilities. In the present study, we implemented a single-cell assay and a scoring scheme to systematically probe the spatial organization of activated EphA receptor in carcinoma cells of different origin. Using this assay, we found that cancer cells retained EphA clustering phenotype upon cell division for several generations and degree of clustering reported for population as well as single-cell migration potential. Finally, using patient-derived cancer cell lines, we probed the evolution of EphA signalling in cancer cell populations that underwent metastatic transformation and acquisition of drug resistance. Taken together, our simple and scalable approach provides a reliable quantitation of EphA associated gene expression and phenotypes in multiple carcinomas and can assay the heterogeneity of cancer cell populations in a cost- and time-effective manner.

cancer biology↗

bioRxiv2019

The chromatin structuring protein HMGA2 influences human subtelomere stability and cancer chemosensitivity

The transient build-up of DNA supercoiling during the translocation of replication forks threatens genome stability and is controlled by DNA topoisomerases (TOPs). This crucial process has been exploited with TOP poisons for cancer chemotherapy. However, pinpointing cellular determinants of the best clinical response to TOP poisons still remains enigmatic. Here, we present an integrated approach and demonstrate that endogenous and exogenous expression of the oncofetal high-mobility group AT-hook 2 (HMGA2) protein exhibited broad protection against the formation of hydroxyurea-induced DNA breaks in various cancer cells, thus corroborating our previously proposed model in which HMGA2 functions as a replication fork chaperone that forms a protective DNA scaffold at or close to stalled replication forks. We now further demonstrate that high levels of HMGA2 also protected cancer cells against DNA breaks triggered by the clinically important TOP1 poison irinotecan. This protection is most likely due to the recently identified DNA supercoil constraining function of HMGA2 in combination with exclusion of TOP1 from binding to supercoiled substrate DNA. In contrast, low to moderate HMGA2 protein levels surprisingly potentiated the formation of irinotecan-induced genotoxic covalent TOP1-DNA cleavage complexes. Our data from cell-based and several in vitro assays indicate that, mechanistically, this potentiating role involves enhanced drug-target interactions mediated by HMGA2 in ternary complexes with supercoiled DNA. Subtelomeric regions were found to be extraordinarily vulnerable to these genotoxic challenges induced by TOP1 poisoning, pointing at strong DNA topological barriers located at human telomeres. These findings were corroborated by an increased irinotecan sensitivity of patient-derived xenografts of colorectal cancers exhibiting low to moderate HMGA2 levels. Collectively, we uncovered a therapeutically important control mechanism of transient changes in chromosomal DNA topology that ultimately leads to enhanced human subtelomere stability. Author SummaryDNA replication fork stability in rapidly dividing cancer cells is of utmost importance for the maintenance of genome stability and cancer cell viability. Cancer cells efficiently prevent fork collapse into lethal double strand breaks as a first line of defense during replication stress, but the corresponding protective mechanisms often remain elusive. Uncontrolled high levels of DNA supercoiling that are generally regulated by topoisomerases can cause replication stress and are major threats to fork stability. Using a multidisciplinary approach, we identified a possible regulatory mechanism of replication stress, which appears to involve mitigating the consequences of DNA topological changes by the oncofetal replication fork chaperone HMGA2. Our work provides mechanistic insights into the control of DNA damage triggered by clinically important anti-cancer drugs, which is mediated by the replication fork chaperone HMGA2. We thereby also identify HMGA2 expression as a predictive therapeutic marker, which could allow clinicians to take informed decisions to prevent tumor recurrence and improve survival.

cancer biology↗

bioRxiv2017

Dynamic expression of tRNA-derived small RNAs define cellular states

Transfer RNA (tRNA)-derived small RNAs (tsRNAs) have recently emerged as important regulators of protein translation and shown to have diverse biological functions. However, the underlying cellular and molecular mechanisms of tsRNA function in the context of dynamic cell-state transitions remain unclear. Here we report the identification of a set of tsRNAs upregulated in differentiating mouse embryonic stem cells (mESCs). Mechanistic analyses revealed primary functions of tsRNAs in regulating polysome assembly and translation. Notably, interactome studies with differentially-enriched tsRNAs revealed a switch in associations with effector RNPs and target mRNAs in different cell-states. We also demonstrate that a specific pool of tsRNAs can interact with Igf2bp1, an RNA-binding protein, to influence the expression of the pluripotency-promoting factor-c-Myc, thereby providing evidence for tsRNAs in modulating stem cell-states in mESCs. Finally, tsRNA expression analyses in distinct, heterologous cell and tissue models of stem/transformed versus differentiated/normal states reveal that tsRNA-mediated regulation of protein translation may represent a global biological phenomenon associated with cell-state transitions.\n\nOne Sentence SummaryIdentification and functional characterization of tRNA-derived small RNAs (tsRNAs) in cell state switches.

molecular biology↗