Biology subjects

Shukla, S.

Publications and source records attributed to Shukla, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

GJB3, a gap junction gene, supports cell growth by mediating cystine uptake and regulating cellular stress pathways in SLC7A11 low adenocarcinomas

Gap junctions are specialized intercellular connections that directly connect the cytoplasm of two cells via protein structure called connexins. Despite extensive research on many cell surface proteins, Gap junction proteins are understudied in cancer. In this study, we used TCGA data to identify genetic and epigenetic changes associated with Gap junction proteins. The analysis identified GJB3 as a key gene with differential methylation and expression patterns, with notable overexpression in COAD and LUAD, correlating significantly with patient survival outcomes. GJB3 knockdown studies revealed reduced cell proliferation and migration. Transcriptomic analysis revealed that GJB3 knockdown induced a cellular stress response, characterized by activation of starvation and autophagy pathways. Western blot analysis confirmed these findings, showing increased phosphorylation of eIF2 and activation of the GCN2-eIF2-ATF4 signaling axis subsequent autophagy induction. We also found that sustained autophagy induced apoptosis mediated cell death. Metabolic profiling revealed a significant decrease in cystine levels in GJB3-deficient cells. We demonstrated that GJB3 plays a crucial role in cystine uptake, especially in cells with low SLC7A11 expression. Furthermore, we showed that GJB3 can be targeted using specific antibodies, establishing it as a potential therapeutic strategy for GJB3-dependent cancers. These findings highlight the significance of GJB3 in cancer progression and its potential as a therapeutic target, offering new insights into its epigenetic regulation and functional role in cellular stress and survival mechanisms.

cancer biology↗

bioRxiv2024

Intratumoral CXCL12 Gradients Contextualize Tumor Cell Invasion, Migration and Immune Suppression in Breast Cancer

Although the CXCL12/CXCR4 pathway has been prior investigated for its prometastatic and immuno- suppressive roles in the tumor microenvironment, evidence on the spatiotemporal regulation of these hallmarks has been lacking. Here, we demonstrate that CXCL12 forms a gradient specifically around cancer cell intravasation doorways, also known as Tumor Microenvironment of Metastasis (TMEM) doorways, thus facilitating the chemotactic translocation of prometastatic tumor cells expressing CXCR4 toward the perivascular TMEM doorways for subsequent entry into peripheral circulation. Fur- thermore, we demonstrate that the CXCL12-rich micro-environment around TMEM doorways may cre- ate immunosuppressive niches, whereby CD8+ T cells, despite being attracted to these regions, often exhibit reduced effector functions, limiting their efficacy. While the CXCL12/CXCR4 pathway can mini- mally influence the overall composition of immune cell populations, it biases the distribution of CD8+ T cells away from TMEM doorways, justifying its prior-established role as immunosuppressive factor for CD8+ T cells. Our research suggests that the complex interactions between CXCL12 and the various tumor and immune cell types contributes not only to the completion of the initial steps of the metastatic cascade, but also offers an immunological "sanctuary" to prometastatic tumor cells homed around TMEM doorways. Overall, our study enhances our current understanding on the mechanisms, via which CXCL12 orchestrates tumor cell behavior and immune dynamics, potentially guiding future thera- peutic strategies to combat breast cancer metastasis and improve anti-tumor immunity.

cancer biology↗

bioRxiv2024

PRMT5-mediated histone methylation regulates alternative splicing via MECP2-PTBP1 to promote EMT in breast cancer hypoxia

Tumor hypoxia induced alterations in the epigenetic landscape and alternative splicing influence cellular adaptations. PRMT5 is a type II protein arginine methyltransferase that regulates several tumorigenic events in many cancer types. However, the regulation of PRMT5 and its direct implication on aberrant alternative splicing under hypoxia remains unexplored. In this study, we observed hypoxia induced upregulation of PRMT5 via the CCCTC binding factor, CTCF. Further, PRMT5-mediated symmetric arginine dimethylation H4R3me2s and H3R8me2s directly regulated the alternative splicing of Transcription Factor 3 (TCF3). Under hypoxia, PRMT5-mediated histone dimethylation at the intronic conserved region (ICR) present between TCF3 exon 18a and exon 18b recruits DNA methyltransferase 3A (DNMT3A), resulting in DNA methylation. DNA methylation at the TCF3-ICR is recognized and bound by Methyl CpG binding protein (MECP2) resulting in RNA-Pol II pausing, promoting the recruitment of the negative splicing factor PTBP1 to the splicing locus of TCF3 mRNA. PTBP1 promotes the exclusion of exon 18a which results in the production of the pro-invasive TCF3-18B (E47) isoform which promotes EMT and invasion of breast cancer cells under hypoxia. Collectively, our results indicate PRMT5-mediated symmetric arginine dimethylation of histones regulates alternative splicing of TCF3 gene thereby enhancing EMT and invasion in breast cancer hypoxia.

cancer biology↗

bioRxiv2024

Interplay of YEATS2 and GCDH mediates histone crotonylation and drives EMT in head and neck cancer

The regulation of gene expression is an integral cellular process orchestrated by epigenetic marks like histone modifications. Perturbations in the activity or abundance of epigenetic factors can lead to tumorigenesis. Remarkably, several metabolites influence the epigenetic landscape in cells. Here, we investigated the interplay between a highly expressed epigenetic factor, YEATS2, and a metabolic enzyme, GCDH, in regulating epithelial-to-mesenchymal transition in head and neck cancer. We report that the histone reader YEATS2 is responsible for increased invasive potential in head and neck cancer in an SP1-dependent manner. YEATS2 functions by maintaining histone crotonylation, and its abrogation leads to a global decrease in the H3K27cr mark. Mechanistically, we report that YEATS2 maintains high promoter H3K27cr levels by assisting in the recruitment of crotonyltransferase p300 at the promoter of the EMT-promoting gene SPARC. Further, we found that the addition of the H3K27cr mark is also dependent on the crotonyl-CoA-producing enzyme GCDH. Overall, we describe a novel mechanism of interplay between epigenetics and metabolism in head and neck tumorigenesis, which results in the enhanced expression of EMT-related genes in a histone crotonylation-dependent manner.

cancer biology↗

bioRxiv2024

Engineered Nanotopographies Induce Transient Openings in the Nuclear Membrane

Materials with engineered nano-scale surface topographies, such as nanopillars, nanoneedles, and nanowires, mimic natural structures like viral spike proteins, enabling them to bypass biological barriers like the plasma membrane. These properties have led to applications in nanoelectronics for intracellular sensing and drug delivery platforms, some of which are already in clinical trials. Here, we present evidence that nanotopographic materials can induce transient openings in the nuclear membranes of various cell types without penetrating the cells, breaching the nucleo-cytoplasmic barrier and allowing uncontrolled molecular exchange across the nuclear membrane. These openings, induced by nanoscale curvature, are temporary and repaired through ESCRT-mediated mechanisms. Our findings suggest a potential for nano topographic materials for direct nuclear sensing and delivery, holding promise for improving the delivery, efficiency, and safety of therapeutic agents to the nucleus.

bioengineering↗

bioRxiv2024

The Open Pediatric Cancer Project

BackgroundIn 2019, the Open Pediatric Brain Tumor Atlas (OpenPBTA) was created as a global, collaborative open-science initiative to genomically characterize 1,074 pediatric brain tumors and 22 patient-derived cell lines. Here, we present an extension of the OpenPBTA called the Open Pediatric Cancer (OpenPedCan) Project, a harmonized open-source multi-omic dataset from 6,112 pediatric cancer patients with 7,096 tumor events across more than 100 histologies. Combined with RNA-Seq from the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA), OpenPedCan contains nearly 48,000 total biospecimens (24,002 tumor and 23,893 normal specimens). FindingsWe utilized Gabriella Miller Kids First (GMKF) workflows to harmonize WGS, WXS, RNA-seq, and Targeted Sequencing datasets to include somatic SNVs, InDels, CNVs, SVs, RNA expression, fusions, and splice variants. We integrated summarized CPTAC whole cell proteomics and phospho-proteomics data, miRNA-Seq data, and have developed a methylation array harmonization workflow to include m-values, beta-vales, and copy number calls. OpenPedCan contains reproducible, dockerized workflows in GitHub, CAVATICA, and Amazon Web Services (AWS) to deliver harmonized and processed data from over 60 scalable modules which can be leveraged both locally and on AWS. The processed data are released in a versioned manner and accessible through CAVATICA or AWS S3 download (from GitHub), and queryable through PedcBioPortal and the NCIs pediatric Molecular Targets Platform. Notably, we have expanded PBTA molecular subtyping to include methylation information to align with the WHO 2021 Central Nervous System Tumor classifications, allowing us to create research-grade integrated diagnoses for these tumors. ConclusionsOpenPedCan data and its reproducible analysis module framework are openly available and can be utilized and/or adapted by researchers to accelerate discovery, validation, and clinical translation.

genomics↗

bioRxiv2024

Conformational switching of Arp5 subunit differentially regulates INO80 chromatin remodeling

The INO80 chromatin remodeler is a versatile enzyme capable of several functions, including spacing nucleosomes equal distances apart, precise positioning of nucleosomes based on DNA shape/sequence and exchanging histone dimers. Within INO80, the Arp5 subunit plays a central role in INO80 remodeling, evidenced by its interactions with the histone octamer, nucleosomal and extranucleosomal DNA, and its necessity in linking INO80s ATPase activity to nucleosome movement. Our investigation reveals that the grappler domain of Arp5 interacts with the acidic pocket of nucleosomes through two distinct mechanisms: an arginine anchor or a hydrophobic/acidic patch. These two modes of binding serve distinct functions within INO80 as shown in vivo by mutations in these regions resulting in varying phenotypes and in vitro by diverse effects on nucleosome mobilization. Our findings suggest that the hydrophobic/acidic patch of Arp5 is likely important for dimer exchange by INO80, while the arginine anchor is crucial for mobilizing nucleosomes.

biochemistry↗

bioRxiv2024

BET inhibitors as a therapeutic intervention in gastrointestinal gene signature-positive castration-resistant prostate cancer.

A subgroup of castration-resistant prostate cancer (CRPC) aberrantly expresses a gastrointestinal (GI) transcriptome governed by two GI-lineage-restricted transcription factors, HNF1A and HNF4G. In this study, we found that expression of GI transcriptome in CRPC correlates with adverse clinical outcomes to androgen receptor signaling inhibitor treatment and shorter overall survival. Bromo- and extra-terminal domain inhibitors (BETi) downregulated HNF1A, HNF4G, and the GI transcriptome in multiple CRPC models, including cell lines, patient-derived organoids, and patient-derived xenografts, while AR and the androgen-dependent transcriptome were largely spared. Accordingly, BETi selectively inhibited growth of GI transcriptome-positive preclinical models of prostate cancer. Mechanistically, BETi inhibited BRD4 binding at enhancers globally, including both AR and HNF4G bound enhancers while gene expression was selectively perturbed. Restoration of HNF4G expression in the presence of BETi rescued target gene expression without rescuing BRD4 binding. This suggests that inhibition of master transcription factors expression underlies the selective transcriptional effects of BETi. SIGNIFICANCEGI transcriptome expression in CRPC is regulated by the HNF1A-HNF4G-BRD4 axis and correlates with worse clinical outcomes. Accordingly, BET inhibitors significantly reduce tumor cell growth in multiple GI-transcriptome-positive preclinical models of CRPC. Our studies point that expression of GI transcriptome could serve as a predictive biomarker to BETi therapy response.

cancer biology↗

bioRxiv2023

Fecal microbial transfer and complex carbohydrates mediate protection against COPD

ObjectiveChronic obstructive pulmonary disease (COPD) is a major cause of global illness and death, most commonly caused by cigarette smoke. The mechanisms of pathogenesis remain poorly understood, limiting the development of effective therapies. The gastrointestinal microbiome has been implicated in chronic lung diseases via the gut-lung axis, but its role is unclear. DesignUsing an in vivo mouse model of cigarette smoke-induced COPD and fecal microbial transfer (FMT), we characterized the fecal microbiota using metagenomics, proteomics and metabolomics. Findings were correlated with airway and systemic inflammation, lung and gut histopathology, and lung function. Complex carbohydrates were assessed in mice using a high resistant starch diet, and in sixteen COPD patients using a randomized, double-blind, placebo-controlled pilot study of inulin supplementation. ResultsFMT alleviated hallmark features of COPD (inflammation, alveolar destruction, impaired lung function), gastrointestinal pathology and systemic immune changes. Protective effects were additive to smoking cessation. Disease features correlated with the relative abundance of Muribaculaceae, Desulfovibrionaceae and Lachnospiraceae family members. Proteomics and metabolomics identified downregulation of glucose and starch metabolism in cigarette smoke-associated microbiota, and supplementation of mice or human patients with complex carbohydrates improved disease outcomes. ConclusionThe gut microbiome contributes to COPD pathogenesis and can be targeted therapeutically. What is already known on this topicO_LIChanges in gut microbiota are associated with COPD but the underlying host and microbial mechanisms are unclear, limiting the therapeutic applications. C_LI What this study addsO_LIMicrobiome composition and metabolism is reproducibly correlated with lung and gastrointestinal pathology in experimental COPD. C_LIO_LIMicrobiome modifying interventions effectively alleviate disease, including protective effects supplementing smoking cessation. C_LIO_LINutritional interventions targeting the microbiome in COPD patients demonstrate efficacy in a small pilot study. C_LI How this study might affect research, practice or policyO_LIMicrobiome-targeting therapeutics and nutritional interventions may be developed for COPD, including as supplements to smoking cessation. C_LI

physiology↗

bioRxiv2023

Mechanism and cellular function of direct membrane binding by the ESCRT and ERES-associated Ca2+-sensor ALG-2

Apoptosis Linked Gene-2 (ALG-2) is a multifunctional intracellular Ca2+ sensor and the archetypal member of the penta-EF hand protein family. ALG-2 functions in the repair of damage to both the plasma and lysosome membranes and in COPII-dependent budding at endoplasmic reticulum exit sites (ERES). In the presence of Ca2+, ALG-2 binds to ESCRT-I and ALIX in membrane repair and to SEC31A at ERES. ALG-2 also binds directly to acidic membranes in the presence of Ca2+ by a combination of electrostatic and hydrophobic interactions. By combining GUV-based experiments and molecular dynamics simulations, we show that charge-reversed mutants of ALG-2 at these locations disrupt membrane recruitment. ALG-2 membrane binding mutants have reduced or abrogated ERES localization in response to Thapsigargin-induced Ca2+ release but still localize to lysosomes following lysosomal Ca2+ release. In vitro reconstitution shows that the ALG-2 membrane-binding defect can be rescued by binding to ESCRT-I. These data thus reveal the nature of direct Ca2+-dependent membrane binding and its interplay with Ca2+-dependent protein binding in the cellular functions of ALG-2.

biophysics↗

bioRxiv2023

Oral administration of a specific p300/CBP Lysine acetyltransferase activator induces synaptic plasticity and repairing spinal cord injury

TTK21 is a small molecule activator of p300/CBP acetyltransferase activity, which upon conjugation with glucose-derived carbon nanosphere (CSP) can efficiently cross the blood-brain barrier and activate histone acetylation in the brain. Its role in adult neurogenesis and retention of long-term spatial memory upon intraperitoneal (IP) administration is well established. In this study, we have successfully demonstrated that CSP-TTK21 can be effectively administered via oral gavage. Using a combination of molecular biology, microscopy, and electrophysiological techniques, we systematically investigated the comparative efficacy of oral administration of CSP and CSP-TTK21 in wild-type mice, evaluating their functional effects in comparison to intraperitoneal (IP) administration. Our findings indicate that CSP-TTK21, when administered orally, induces long-term potentiation in the hippocampus without significantly altering basal synaptic transmission, a response comparable to that achieved through IP injection. Remarkably, in a spinal cord injury model, oral administration of CSP-TTK21 exhibits equivalent efficacy to IP administration. Furthermore, our research demonstrates that oral delivery of CSP-TTK21 leads to improvements in motor functions, histone acetylation dynamics, and increased expression of regeneration associated genes (RAGs) in a spinal injury rat model, mirroring the effectiveness of IP administration. Collectively, these results underscore the potential utility of CSP as an oral drug delivery system, particularly for targeting the neural system.

neuroscience↗

bioRxiv2023

Tau fibrils induce nanoscale membrane damage and nucleate cytosolic tau at lysosomes

The prion-like spread of protein aggregates is a leading hypothesis for the propagation of neurofibrillary lesions in the brain, including the spread of tau inclusions associated with Alzheimers disease. The mechanisms of cellular uptake of tau seeds and subsequent nucleated polymerization of cytosolic tau are major questions in the field, and the potential for coupling between the entry and nucleation mechanisms has been little explored. We found that in primary astrocytes, endocytosis of tau seeds leads to their accumulation in lysosomes. This in turn leads to lysosomal swelling, deacidification and recruitment of ESCRT proteins, but not Galectin-3, to the lysosomal membrane. These observations are consistent with nanoscale damage of the lysosomal membrane. Using live cell and STORM, imaging, nucleation of cytosolic tau occurs primarily at the lysosome membrane under these conditions. These data suggest that tau seeds escape from lysosomes via nanoscale damage rather than wholesale rupture, and that nucleation of cytosolic tau commences as soon as tau fibril ends emerge from the lysosomal membrane.

cell biology↗

bioRxiv2023

Neuroendocrine control of synaptic transmission by PHAC-1 in C. elegans.

A dynamic interplay between synaptic and neuromodulatory signalling guarantees flexible but robust neuronal circuits. Presynaptic modulation plays a crucial role in controlling the excitatory-inhibitory balance within networks. Here, we designed a genetic screen to identify genes involved in the neuromodulation of the C. elegans neuromuscular junctions (NMJ) and identified the orthologs of the Protein Phosphatase 1 regulatory subunit PHACTR1 (phac-1) and the presynaptic phosphoproteins Synapsin (snn-1). Five de novo variants of human PHACTR1 are associated with severe early-onset epilepsies (DEE70). To understand the impact of these variants, we introduced the DEE70 mutations into phac-1. These mutations resulted in the formation of a constitutively active PP1-PHAC-1 holoenzyme that disrupts cholinergic signalling at the NMJ. By using quantitative fluorescence imaging, electron microscopy and electrophysiology, we found that the constitutive holoenzyme alters the synaptic vesicle cycle, reduces the synaptic vesicle reserve pool, and increases neuropeptide release by dense-core vesicles. Notably, while SNN-1 phosphoregulation contributes to NMJ signalling, genetic interactions suggest that SNN-1 is not the main effector of PP1-PHAC-1 holoenzyme signalling. Collectively, our results confirm the pathogenicity of DEE70 variants, clarify their dominant-positive effects, and provide evidence of a presynaptic mode of action for DEE70.

neuroscience↗

bioRxiv2023

Oncometabolite lactate enhances breast cancer progression by orchestrating histone lactylation-dependent c-Myc expression

Owing to the enhanced glycolytic rate, cancer cells generate lactate copiously, which in turn, promotes lactylation of histone. Even though histone lactylation has been explored to alter the expression of few genes, the role of this epigenetic modification in regulating the expression of oncogenes is largely unchartered. In this study, using breast cancer cell lines their mutants (which exhibit lactate-deficient metabolome), we have identified that intracellular lactate promotes histone lactylation-dependent c-Myc upregulation. Furthermore, we report that the c-Myc upregulates serine/arginine splicing factor 10 (SRSF10) to drive alternative splicing in breast cancer cells. Our findings provide novel mechanistic insights into the role assayed by aerobic glycolysis in orchestrating alternative splicing that collectively drive breast tumorigenesis. Moreover, we also envisage that chemotherapeutic interventions attenuating glycolytic rate can restrict breast cancer progression by impeding the c-Myc-SRSF10 axis.

cancer biology↗

bioRxiv2023

Hypoxia-induced CTCF mediates alternative splicing via coupling chromatin looping and RNA Pol II pause to promote EMT in breast cancer

Cancer cells experiencing hypoxic stress employ Epithelial-Mesenchymal Transition (EMT) to undergo metastasis through rewiring chromatin landscape, epigenetics, and importantly alternative splicing. Here, we investigated the role of CTCF, chromatin, epigenetic and alternative splicing modulator under hypoxia to promote EMT. Our result shows that hypoxia-induced epigenetic changes upregulate CTCF expression in breast cancer. We delineate that CTCF is a direct target of HIF1 and the hypoxia-induced HIF1-CTCF axis functionally contributes to promoting EMT in breast cancer cells. Finally, our work uncovers COL5A1, an EMT gene, as a direct target of CTCF. We demonstrated that hypoxia-mediated CTCF enrichment on COL5A1 promoter regulates expression as well as alternative splicing events to promote EMT. Here, we put forward an intricate mechanism of alternative splicing where CTCF-mediated promoter-exon upstream looping regulates DNA de-methylation and CTCF-mediated RNA Pol II pausing at COL5A1 exon 64A. Our global analysis of CTCF-ChIP-seq data reveals that the hypoxia-induced differential CTCF occupancy possibly regulates gene expression and alternative splicing events of many genes that are enriched in the EMT pathway, cancer cell motility and invasion, angiogenesis, and stemness under hypoxia, similarly to the proposed model. Finally, we employed the epigenetic modulator dCas9-DNMT3A system to specifically disrupt HIF1 or CTCF binding under hypoxia and hence the HIF1-CTCF-COL5A1exon64A axis that alleviates the EMT potential of breast cancer cells that may represent a novel therapeutic target in breast cancer. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=180 SRC="FIGDIR/small/539689v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@e15c15org.highwire.dtl.DTLVardef@1649a71org.highwire.dtl.DTLVardef@1d77481org.highwire.dtl.DTLVardef@21f148_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

molecular biology↗

bioRxiv2023

Chromatin condensation delays human mesenchymal stem cells senescence by safeguarding nuclear damages during long-term in vitro expansion

Human mesenchymal stem cells (hMSCs) are multipotent cells that can differentiate into adipocytes, chondrocytes and osteoblasts. Due to their differentiation potential, hMSCs are among the most frequently used cells for therapeutic applications in tissue engineering and regenerative medicine. However, the number of cells obtained through isolation alone is insufficient for hMSC-based therapies and basic research, necessitating their in-vitro expansion. Conventionally, this is often carried out on rigid surfaces such as tissue culture petriplates (TCPs). However, during in-vitro expansion, hMSCs lose their proliferative ability and multilineage differentiation potential, making them unsuitable for clinical use. Although multiple approaches have been tried to maintain hMSC stemness over prolonged expansion, finding a suitable culture system to achieve this remains an unmet need. Recently, few research groups including ours have shown that hMSCs maintain their stemness over long passages when cultured on soft substrate. In addition, it has been shown that hMSCs cultured on soft substrates have more condensed chromatin and lower levels of histone acetylation compared to those cultured on stiff substrates. It has also been shown that condensing/decondensing chromatin by deacetylation/acetylation can delay/hasten replicative senescence in hMSCs during long-term expansion on TCPs. However, how chromatin condensation/decondensation influences nuclear morphology and DNA damage - which are strongly related to the onset of senescence and cancer - is still not known. To answer this question, here we cultured hMSCs for long duration (P4-P11) in presence of epigenetic modifiers histone acetyltransferase inhibitor (HATi) which promotes chromatin condensation by preventing histone acetylation and histone deacetylase inhibitor (HDACi) which promotes chromatin decondensation and investigated their effect on various nuclear markers related to senescence and cancer. We have found that consistent acetylation causes severe nuclear abnormalities whereas chromatin condensation by deacetylation helps in safeguarding nucleus from damages caused by in-vitro expansion.

cell biology↗

bioRxiv2022

DeepMPS: Development and validation of a deep learning model for whole slide image base prognostic prediction of low grade Lung adenocarcinoma patients

Lung adenocarcinoma (LUAD) is one of the most common cancers, and patients prognostication is crucial for treatment decisions. Histopathological images are the most generally accessible clinical information, however they have not been employed in clinical settings for prognosis. In this study, we used WSIs and clinical data from TCGA (training and testing) and East Asian Cohort (EAS, Validation) to develop and validate DL-based prognosticator. To circumvent the need for manual ROI generation, WSIs from these patients were divided into smaller patches and scored. DeepMPS prediction model was built using the top scoring 226,383 patches. The DeepMPS model showed a C-index of 0.638 in the TCGA training cohort. The univariate and multivariate cox regression analysis identified DeepMPS as an independent predictor of survival (HR: 9.48, p-value: <0.0001) in the training cohort. The training cohort of patients was separated into low and high-risk groups at various points. Kaplan-Meier analysis showed the highest difference in survival of low and high-risk patients at the 75th percentile (HR: 3.58, 95% CI: 2.57-5.00, p-value: <0.0001). At the same cut-off as the training samples, TCGA testing cohort patients demonstrated a significant difference in survival when split into low and high-risk patients (HR: 2.30, 95% CI: 1.11-4.82, p-value: 0.044). The DeepMPS model was validated in the EAS cohort patients. DeepMPS risk score significantly segregated EAS patients into low and high-risk groups at the same cut-off point as the training cohort (HR: 2.09, 95% CI: 1.11-3.97, p-value: 0.008). In multivariate Cox regression analysis, the DeepMPS score outperformed the stage in survival prediction. We also compared the DeepMPS model with the previously developed DL-based model to show that it was the best predictor of survival with the highest C-index. In conclusion, we developed a robust DL-based prognostic model which can predict the LUAD outcome without manual intervention using histopathological images. Author SummaryRight from the initial step of cancer diagnosis, histopathological images are the widely relied source of information for therapeutic decision making. Though these images carry a substantial amount of information, their use remains restricted to determining the grade of the tumor by pathologists. The advent of computational techniques has given rise to the ability to capture vital information besides the grade of the tumor, which humans might not be able to quantify visually. To this end, this work proposes a deep learning based model, Deep Multi-Modal Prognosis System (DeepMPS), to predict the prognosis of the patients based on the histopathological images to provide additional information to the pathologist which will aid in clinical decision making. DeepMPS predicts a risk score associated with each individual based on histopathological images and clinical factors. The risk score obtained from the proposed system is an independent predictor of survival. As the proposed system is independent of the manual region-of-interest (RoI) generation, it will ease the pathologists workload.

pathology↗

bioRxiv2022

8-HQA Adjusts the Number and Diversity of Bacteria in the Gut Microbiome of Spodoptera littoralis

Quinolinic carboxylic acids are known for their metal ion chelating properties in insects, plants and bacteria. The larval stages of the lepidopteran pest, Spodoptera littoralis, produce 8-hydroxyquinoline-2-carboxylic acid (8-HQA) in high concentrations from tryptophan in the diet. At the same time, the larval midgut is known to harbor a bacterial population. The motivation behind the work was to investigate whether 8-HQA is controlling the bacterial community in the gut by regulating the concentration of metal ions. Knocking out the gene for kynurenine 3-monooxygenase (KMO) in the insect using CRISPR/Cas9 eliminated production of 8-HQA and significantly increased bacterial numbers and diversity in the larval midgut. Adding 8-HQA to the diet of knockout larvae caused a dose-dependent reduction of bacterial numbers with minimal effects on diversity. Enterococcus mundtii dominates the community in all treatments, probably due to its highly efficient iron uptake system and production of the colicin, mundticin. Thus host factors and bacterial properties interact to determine patterns of diversity and abundance in the insect midgut.

microbiology↗