Biology subjects

Dutta, A.

Publications and source records attributed to Dutta, A..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Integrative plasma lipidomics and proteomics profiling to decipher potential biomarkers of dilated cardiomyopathy

BackgroundDilated cardiomyopathy (DCM), primarily characterised by left ventricular dilatation and systolic dysfunction, is one of the leading causes of heart failure and requires a critical clinical investigative strategy. However, conventional imaging techniques such as echocardiography and MRI, along with some classical CVD markers (NTproBNP, cTnT), fall short in diagnosing DCM-specific phenotypes. Thus, the need for biochemical markers with enhanced accuracy to DCM is of enormous importance. Lipids and proteins play essential roles in maintaining myocardial function. The homeostatic disruption of such biomolecules might contribute to DCM pathogenesis, thus offering to serve as potential biomarkers for DCM. Moreover, the lack of global lipidomics studies and specific protein markers in DCM patients prompted us to explore the disease pathophysiology through an integrative omics-based analysis coupled with an ML-derived approach. ObjectiveTo identify accurate, precise and specific circulatory lipidomic and proteomic biomarkers of DCM using high-resolution mass spectrometry and machine learning (ML)-based approaches. MethodsHigh-resolution-mass-spectrometry-based lipidomics and proteomics were applied to identify lipid and protein biomarkers in a cohort (n=360) of healthy and DCM patients. Top protein classifiers were further evaluated using single-cell transcriptomics on publicly available datasets from DCM myocardium and validated using ELISA. A biomarker panel was built by the integration of lipidomics and validated proteomics data using machine-learning-based approaches. ResultsA total of 125 lipids and 10 proteins have been primarily discovered with significant alterations in DCM (0.8 [≥] FC [≥] 1.2; padj < 0.05). Using a Boruta-based ML approach, we identified 39 lipids and 10 proteins as primary discriminators between DCM and controls. ELISA validation confirmed the potential of B2M (6.85 {+/-} 2.86 g/ml vs. 4.26 {+/-} 1.25 g/ml; p < 0.0001) and Tetranectin (CLEC3B) (1.99 {+/-} 0.88 g/ml vs. 2.49 {+/-} 0.90 g/ml; p = 0.0006) to emerge as protein biomarkers of DCM. In line with that, the single-cell transcriptomic analysis showed a similar trend of alteration of tetranectin (CLEC3B) in cardiomyocytes and {beta}2microglobulin (B2M) in varied cell types of the myocardium. Further, Integrated ROC analysis combining the top 8 lipid discriminators with B2M and CLEC3B achieved an AUC of 0.995, demonstrating enhanced diagnostic precision compared to the classical CVD marker NTproBNP (0.965). ConclusionThis study offers a system-omics-based perspective on first-global lipidomic and proteomic changes associated with DCM pathophysiology, with a high potential for diagnostic application.

systems biology↗

bioRxiv2025

High-throughput Activity Reprogramming of Proteases (HARP)

Developing potent and selective protease inhibitors remains a grueling, iterative, and often unsuccessful endeavor. Although macromolecular inhibitors can achieve single-enzyme specificity, platforms used for macromolecular inhibitor discovery are optimized for high-affinity binders, requiring extensive downstream biochemical characterization to isolate rare inhibitors. Here, we developed the High-throughput Activity Reprogramming of Proteases (HARP) platform, HARP is a yeast-based functional screen that isolates protease-inhibitory macromolecules from large libraries by coupling their inhibition of endoplasmic reticulum-resident proteases to a selectable phenotype on the cell surface. Endowed with high dynamic range and resolution, HARP enabled the isolation of low-nanomolar-range inhibitory nanobodies against tobacco etch virus protease and human kallikrein 6, including a rare 7.6 nM KI TEVp uncompetitive inhibitor. Structural modeling and deep sequencing all provide insights into the molecular determinants of inhibitors and reinforce HARPs foundational findings. Overall, HARP is a premier platform for discovering modulatory macromolecules from various synthetic scaffolds against enzyme targets. Graphical AbstractO_ST_ABSWorkflow of HARPC_ST_ABSA yeast-based reporter of the interaction between a protease, its canonical substrate, and a modulator library within the yeast cell. Quantifying this interaction occurs by fluorescently labeling the displayed substrate cassettes on the surface of the cells, where the desired function (correlating with phenotype) can be selected using fluorescent-activated cell sorting (FACS). Isolated populations are sequenced and purified in preparation for secondary characterization to determine modulator effects and interaction strengths between the modulator and the protease target.

synthetic biology↗

bioRxiv2025

Multi-scale classification decodes the complexity of the human E3 ligome

E3 ubiquitin ligases are key regulators of protein homeostasis, targeting specific proteins for degradation via the ubiquitin-proteasome system (UPS). They provide crucial substrate specificity, making them promising candidates for the design of novel therapeutics. This work presents a comprehensive, annotated dataset of high-confidence catalytic human E3 ligases, termed the "E3 ligome". Integrating disparate data from various granularity layers, including protein sequence, domain architecture, 3D structure, function, localization, and expression, we learn an emergent distance metric, capturing authentic relationships within this heterogeneous group. A weakly-supervised hierarchical classification framework identifies conserved features of E3 families and subfamilies, consistent with RING, HECT, and RBR classes. This classification explains functional segregation, identifies multi-subunit and standalone enzymes, and integrates substrate and small molecule interaction networks. Our analysis provides a global view of E3 biology, opening new strategies for drugging E3-substrate networks, including drug re-purposing and designing new E3 handles.

bioinformatics↗

bioRxiv2025

Exploration of the Anticancer Activity of Selaginella bryopteris-derived Silver Nanoparticles

AbstractOvarian cancer is characterized by chronic hormonal imbalances and associated symptoms like irregular menstruation, fertility problems and abdominal discomfort. Poly ADP-ribose polymerases (PARPs) are proteins that play a crucial role in DNA repair pathways like base excision repair (BER). PARP family proteins exhibit catalytic activities which facilitate the transport of ADP-ribose to targeted proteins. Inhibition of PARP proteins in cancer cells with BRAC1/2 gene mutations impairs the process of Single Strand Break (SSBs) repairs followed by Double Strand Breaks (DSBs), stalling replication, leading to apoptosis. PARP1 protein inhibition is an innovative therapeutic approach in cancer treatment. Commercially available drugs like Olaparib and Rucaparib are used as PARP1 inhibitors to treat ovarian cancer, however the development of effective new therapeutic drugs is urgently needed to overcome drug toxicity and resistance. In this study, we synthesized silver nanoparticles (AgNPs) from the leaf extract of Selaginella bryopteris demonstrating their cytotoxic nature against the ovarian cancer SKOV-3 cell line, with an IC50 value of 7.81{micro}g/ml. We also observed cell death in cancer cells with an ROS upsurge induced by S. bryopteris AgNPs. Our findings also elaborate on the role of Rhamnetin, a S. bryopteris phytochemical that exhibits active site targeting of PARP-1 residues.

biochemistry↗

bioRxiv2024

A 36-base hairpin within lncRNA DRAIC, which is modulated by alternative splicing, interacts with the IKKα coiled-coil domain and inhibits NF-kB and tumor cell phenotypes

A tumor-suppressive long noncoding RNA (lncRNA) DRAIC (down-regulated RNA in cancers) inhibits NF-{kappa}B activity and physically interacts with IKK, a kinase component of the IKK complex, in several cancer types. Here we explore the precise molecular mechanism involved in this interaction and suppression. Using SHAPE-MaP, we identified a 36-nucleotide hairpin (A+B) within DRAIC that is necessary and sufficient for its anti-oncogenic function. RNA immunoprecipitation (RIP) and Electrophoretic mobility shift assays (EMSA) confirmed this hairpin physically interacts with the coiled coil domain of IKK. A+B RNA has a high binding affinity (KD [~]1-7 nM) to the coiled-coil domain of IKK. The binding of A+B disrupts the dimerization of NEMO and IKK coiled-coil domains, a critical step for IKK action. Consistent with this, A+B inhibits the phosphorylation of the NF-{kappa}B inhibitor I{kappa}B and suppresses NF-{kappa}B activity. Publicly available tumor RNAseq data revealed that alternative splicing modulates the presence of this critical hairpin: the inclusion of exon 4a (encoding one side of the A+B hairpin) in lung tumors correlates with reduced NF-{kappa}B activity. By demonstrating that the A+B hairpin is both necessary and sufficient to inhibit IKK and oncogenic phenotypes, this study underscores the centrality of IKK interaction and NF-{kappa}B inhibition in DRAIC-mediated cancer suppression and indicates that the activity of this lncRNA is regulated by alternative splicing. This study also reveals the first example of a short RNA disrupting coiled-coil dimerization, offering a new approach to disrupt such dimerization in cancer biology.

molecular biology↗

bioRxiv2024

Regulation of epigenetics and chromosome structure by human ORC2

We report a multi-omics study in a human cell line with mutations in three subunits of Origin Recognition Complex (ORC). The ORC subunits bind to DNA independent of each other in addition to as part of a common six-subunit ORC. DNA-bound ORC2 compacts chromatin and attracts repressive histone marks to focal areas of the genome, but ORC2 also activates chromatin at many sites and protects the genes from repressive marks. The epigenetic changes regulate hundreds of genes, including some epigenetic regulators, adding an indirect mechanism by which ORC2 regulates epigenetics without local binding. DNA-bound ORC2 also prevents the acquisition of CTCF at focal sites in the genome to regulate chromatin loops and indirectly affect epigenetics. Thus, our study reveals the genes and ORC1 regions bound by individual ORC subunits and suggests their role as epigenetics and chromosome structure regulators, independent of the role of the six-subunit ORC in DNA replication.

genomics↗

bioRxiv2024

Chromatin regulator HELLS mediates SSB repair and responses to DNA alkylation damage.

The SNF2 family chromatin remodeler HELLS has emerged as an important regulator of cell proliferation, genome stability, and several cancer pathways. Significant upregulation of HELLS has been reported in 33 human cancer types. While HELLS has been implicated in DNA damage response, its function in DNA repair is poorly understood. Here we report a new regulatory link between HELLS and single-strand break (SSB) repair in cellular responses to DNA alkylation damage. We found that loss of HELLS impairs SSB repair, and selectively sensitizes cells to DNA alkylating agents and PARP inhibitors (PARPi). Furthermore, we found that HELLS is co-expressed with PARP1 in cancer cells, and its loss is synthetic lethal with homologous recombination deficiency (HRD). This work unveils new functions of HELLS in modulating SSB repair and responses to clinically relevant DNA alkylation damage, thus offering new insights into the potential therapeutic value of targeting HELLS in cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=158 SRC="FIGDIR/small/629292v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@2bbd3eorg.highwire.dtl.DTLVardef@1956f14org.highwire.dtl.DTLVardef@1afcb7corg.highwire.dtl.DTLVardef@58504c_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2024

ecPath detects ecDNA in tumors from histopathology images

Circular extrachromosomal DNA (ecDNA) can drive tumor initiation, progression and resistance in some of the most aggressive cancers and is emerging as a promising anti-cancer target. However, detection currently requires costly whole-genome sequencing (WGS) or labor-intensive cytogenetic or FISH imaging, limiting its application in routine clinical diagnosis. To overcome this, we developed ecPath (ecDNA from histopathology), a computational method for predicting ecDNA status from routinely available hematoxylin and eosin (H&E) images. ecPath implements a deep-learning method we call transcriptomics-guided learning, which utilizes both transcriptomics and H&E images during the training phase to enable successful ecDNA prediction from H&E images alone, a task not achievable with models trained on H&E images only. It is trained on more than 6,000 tumor whole-slide images from the TCGA cohort with the best performance in predicting ecDNA status in brain and stomach tumors (average AUC=0.78). ecPath revealed that ecDNA-positive tumors are enriched with pleomorphic, larger and high-density nuclei. Testing in an independent cohort, ecPath predicted ecDNA status of 985 pediatric brain tumor patients with an AUC of 0.72. Finally, we applied ecPath to identify ecDNA-positive tumors in the TCGA cohort for which no WGS data were available. Like WGS-based ecDNA-positive labels, the predicted ecDNA-positive status also identify poor prognoses for low grade glioma patients. These results demonstrate that ecPath enables the detection of ecDNA from routinely available H&E imaging alone and help nominate aggressive tumors with ecDNA to study and target it.

pathology↗

bioRxiv2024

Specific origin selection and excess functional MCM2-7 loading in ORC-deficient cells.

The six subunit Origin Recognition Complex (ORC) loads excess MCM2-7 on chromosomes to promote initiation of DNA replication and is believed to be important for origin specification. Mapping of origins in cancer cell lines engineered to delete three of the subunits, ORC1, ORC2 or ORC5 shows that specific origins are still used and are mostly at the same sites in the genome as in wild type cells. The few thousand origins that were up-regulated in the absence of ORC suggest that GC/TA skewness and simple repeat sequences facilitate, but are not essential for, origin selection in the absence of the six-subunit ORC. Despite the lack of ORC, excess MCM2-7 is still loaded at comparable rates in G1 phase to license dormant origins and is also repeatedly loaded in the same S phase to permit re-replication. Thus, origin specification and excess MCM2-7 loading on origins do not require the six-subunit ORC in human cancer cell lines.

molecular biology↗

bioRxiv2024

A novel mechanism for the uptake of enterobactin-chelated ferric ions by the mitochondria and subsequent reduction to ferrous ions inside

Conventional knowledge of mitochondrial iron metabolism talks about the export of iron in its doubly charged state once it is reduced inside the cell until it reaches the mitochondria. At physiological oxygen tension and pH 7.4, the comparatively soluble Fe(II) is easily available. Fe(III) hydrolyses to generate insoluble ferric hydroxides. Iron must be regularly chaperoned because of its near insolubility and potential toxicity due to redox activity. All tissues pick up iron through the binding of transferrin (Tf) to the transferrin receptor 1 (TfR1), followed by the complexs internalisation through receptor-mediated endocytosis. The low pH created by the operation of a proton pump within the endosome reduces Tfs affinity for iron. Importantly, the TfR1 promotes iron escape from Tf in the pH range (pH 5-5.5) reached by the endosome. A "trap," such as pyrophosphate, is needed in vitro for iron release from Tf. However, a physiological chelator that can play this role has not yet been discovered. Fe(III) is hypothesised to be reduced to Fe(II) in erythroid cells by a ferrireductase known as the six-transmembrane epithelial antigen of the prostate 3 in the endosomal membrane after being released from Tf in the endosome. Following this, the divalent metal transporter-1 (DMT1) transports Fe(II) through the endosomal membrane and, it is generally accepted that this generates the cytosolic labile or chelatable iron pool. This reservoir of iron is believed to provide the metal for metabolic requirements, including as iron intake by the mitochondrion for haem and ISC synthesis, as well as storage in the cytosolic protein ferritin. The possibility of Fe(III) entering the mitochondria has not been explored before. A series of dockings shows that binding of the alpha subunit to a complex of Fe(III) with enterobactin is as stable as the binding with of the same chelator with Fe(II). Enterobactin is a bacterial iron chelator thought to play an integral role in host iron metabolism. Our results suggest an interesting possibility of iron being trafficked to the mitochondria as Fe(III). We propose a potential mechanism of Fe(III) trafficking and subsequent reduction to Fe(II) inside the mitochondria.

biochemistry↗

bioRxiv2024

CaMKII induces an autophagy-dependent anabolic response in Articular Chondrocytes

ObjectiveThe objective of this study was to elucidate the role of Calcium calmodulin-dependent Kinase II (CaMKII) in articular chondrocytes and its involvement in osteoarthritis (OA) pathogenesis. By performing gain and loss of function experiments, the research aimed to determine how CaMKII modulates chondrocyte metabolism, anabolic and catabolic processes, hypertrophic differentiation, and autophagy within the articular cartilage. DesignArticular cartilage was harvested from patients undergoing joint replacement surgery for OA, and adult human articular chondrocytes (AHACs) were isolated and cultured. Recombinant adenoviruses were used to overexpress a constitutively active form of CaMKII{gamma} (AdCaMKII) or inhibit CaMKII activity (AdAIP). Various assays, including RT-PCR analysis, alcian blue staining of Micromass cultures, immunofluorescence, and Western blotting, were performed to assess the effects of CaMKII modulation on chondrocyte function. ResultsOverexpression of activated CaMKII{gamma} promoted anabolism, evidenced by increased expression of SOX9, COL2A1, and ACAN, and decreased MMP-13 levels. It also enhanced proteoglycan content in AHAC micromass cultures. Furthermore, CaMKII counteracted the catabolic effects of IL-1{beta} and preserved proteoglycan content. We also observed decreased chondrocyte proliferation and increased synthesis of hypertrophic marker Type X Collagen. CaMKII activation was found to induce autophagy, as indicated by increased phosphorylation of Beclin1 and decreased p62 expression. The anabolic effects of CaMKII were dependent on autophagy, as inhibition of autophagy with Bafilomycin prevented the CaMKII-induced increase in glycosaminoglycan content. ConclusionsCaMKII plays a significant role in modulating chondrocyte metabolism and maintaining cartilage homeostasis. It promotes anabolic processes, counteracts catabolic stimuli, and induces autophagy in articular chondrocytes. However, it also promotes hypertrophic differentiation, highlighting the complexity of CaMKII-mediated signalling in cartilage. Understanding these pathways could lead to new therapeutic strategies that leverage CaMKIIs anabolic potential while mitigating its pro-degenerative effects.

cell biology↗

bioRxiv2024

Computational screening of T-muurolol for an alternative antibacterial solution against Staphylococcus aureus infections: A state-of-the-art phytochemical-based drug discovery approach

Staphylococcus aureus infections present a significant threat to the global healthcare system. The increasing resistance to existing antibiotics and their limited efficacy underscores the urgent need to identify new antibacterial agents with low toxicity to effectively combat various S. aureus infections. Hence, in this study, we have screened T-muurolol for possible interactions with several S. aureus-specific bacterial proteins to establish its potential as an alternative antibacterial agent. Based on binding affinity and interactions with amino acids T-muurolol was identified as a potential inhibitor of S. aureus lipase, dihydrofolate reductase, penicillin-binding protein 2a, D-Ala:D-Ala ligase, and RPP TetM, which indicates its potentiality against S. aureus and its multi-drug resistant strains. Also, T-muurolol exhibited good antioxidant and anti-inflammatory activity by showing strong binding interactions with FAD-dependent NAD(P)H oxidase, and cyclooxygenase-2. Consequently, MD simulation and recalculating binding free energies elucidated its binding interaction stability with targeted proteins. Furthermore, quantum chemical structure analysis based on density functional theory (DFT) depicted a higher EHOMO-LUMO energy gap with a lower chemical potential index, and moderate electrophilicity suggests its chemical hardness and stability and less polarizability and reactivity. Additionally, pharmacological parameters based on ADMET, Lipinskis rules, and bioactivity score validated it as a promising drug candidate with high activity toward ion channel modulators, nuclear receptor ligands, and enzyme inhibitors. In conclusion, the current findings suggest T-muurolol as a promising alternative antibacterial agent that might be a potential phytochemical-based drug against S. aureus. This study also suggests further clinical research before human application. Author SummaryStaphylococcus aureus significantly contributes to human mortality, with over 1 million deaths annually accredited to its infections. At the same time, antimicrobial resistance (AMR) is a critical public health issue, responsible for an estimated 1.27 million deaths globally in 2019. The overuse and abuse of antimicrobials in both human and veterinary medicine are primary drivers of AMR, complicating the treatment of infections and increasing the risks associated with surgeries and other medical events. Despite the availability of antimicrobials such as methicillin, vancomycin, daptomycin, and linezolid, the emergence of multidrug-resistant S. aureus poses a formidable challenge to effective treatment. Due to the limited efficacy and increasing resilience to current antibiotics, there is an urgent need to discover new and effective antibacterial drugs against S. aureus. Since time immemorial, phytochemicals have been valued for their rich biological properties and safety in treating bacterial infections. In this study, we have computationally investigated T-muurolol as a potential alternative antibacterial agent. Our molecular docking and simulation approaches provide insights into the interactions of T-muurolol as an inhibitor of S. aureus-specific bacterial proteins. Additionally, pharmacokinetic and quantum chemical structure analyses offer valuable information about T-muurolols potential as a drug candidate, supporting its further development as an antibacterial agent.

pharmacology and toxicology↗

bioRxiv2024

Endo-reduplication in mouse liver after conditional mutation of ORC2 and combined mutation of ORC1 and ORC2

The six subunit ORC is essential for initiation of DNA replication in eukaryotes. Cancer cell-lines in culture can survive and replicate DNA replication after genetic inactivation of individual ORC subunits, ORC1, ORC2 or ORC5. In primary cells, ORC1 was dispensable in the mouse liver for endo-reduplication, but this could be explained by the ORC1 homolog, CDC6, substituting for ORC1 to restore functional ORC. Here, we have created mice with a conditional deletion of ORC2, which does not have a homolog. Although mouse embryo fibroblasts require ORC2 for proliferation, mouse hepatocytes synthesize DNA in cell culture and endo-reduplicate in vivo without ORC2. Mouse livers endo-reduplicate after simultaneous deletion of ORC1 and ORC2 both during normal development and after partial hepatectomy. Since endo-reduplication initiates DNA synthesis like normal S phase replication these results unequivocally indicate that primary cells, like cancer cell lines, can load MCM2-7 and initiate replication without ORC.

genetics↗

bioRxiv2024

Remodeling Ca2+ dynamics by targeting a promising E-box containing G-quadruplex at ORAI1 promoter in triple-negative breast cancer.

ORAI1 is an intrinsic component of store-operated calcium entry (SOCE) that strictly regulates Ca2+ influx in most non-excitable cells. ORAI1 has been extensively studied to have been overexpressed in various cancer phenotypes, and its signal transduction has been associated with oncotherapy resistance. There is extensive proteomic interaction of ORAI1 with other channels and effectors, resulting in various altered phenotypes. However, the transcription regulation of this gene is not well understood. We have found a putative G-quadruplex (G4) motif, ORAI1-Pu, in the upstream promoter region of the gene, having regulatory functions. High-resolution 3-D NMR structure elucidation suggests that ORAI1-Pu is a stable parallel-stranded G4, having an unusual 8-nt loop imparting dynamics without affecting the structural stability. The protruded loop further houses an E-box motif that provides a docking site for transcription factors like Zeb1. The G4 structure was also endogenously observed using Chromatin Immunoprecipitation (ChIP) with anti-G4 antibody (BG4) in the MDA-MB-231 cell line overexpressing ORAI1. Ligand-mediated stabilization suggested that the stabilized G4 represses transcription in cancer cell line MDA-MB-231. Downregulation of transcription further cascaded down to a decrease in Ca2+ entry by the SOCE pathway, as observed by Fura-2 confocal Ca2+ imaging.

biochemistry↗

bioRxiv2024

Recurrent loss of crossover interference punctuates the recombination landscape across yeast species

Meiotic recombination is essential for the accurate chromosome segregation and the generation of genetic diversity through crossover and gene conversion events. Although this process has been studied extensively in a few selected model species, understanding how its properties vary across species remains limited. In this context, we first characterized the meiotic recombination landscape and properties of the Kluyveromyces lactis budding yeast. We then conducted a comprehensive analysis of 28,897 recombination events spanning 567 meioses in five budding yeast species including Saccharomyces cerevisiae, Saccharomyces paradoxus, Lachancea kluyveri, Lachancea waltii and K. lactis. We observed variations in the recombination landscapes and properties across these species. The Saccharomyces yeasts displayed higher recombination rates compared to the non-Saccharomyces yeasts. In addition, bona fide crossover interference and associated crossover homeostasis were found in the Saccharomyces species only. The evolutionarily conserved ZMM pathway, essential for generating interference-dependent crossovers, has undergone multiple losses throughout evolution, suggesting variations in the regulation of crossover formation. Finally, recombination hotspots, although highly conserved within the Saccharomyces yeasts are not conserved beyond the Saccharomyces genus. Overall, these results highlight great variability and evolution in the recombination landscape between species.

genomics↗

bioRxiv2024

Evaluation of melanocyte stem cell population in vitiliginous skin pre- and post-narrow-band UVB phototherapy

Vitiligo vulgaris is an autoimmune disorder characterized by the destruction of epidermal melanocytes leading to white lesions devoid of pigmentation. The destruction of epidermal melanocytes. Is driven by tissue-resident and circulatory immune cells that maintain an inflammatory milieu. Two percent of the global population suffer from vitiligo vulgaris, of which, prevalence is higher in the Indian population. Narrow-band UV-B (NBUVB) phototherapy is commonly used as an economical, non-invasive, and well-tolerated treatment modality. NBUVB promotes the migration of melanocyte stem cells (MelSC) to the epidermis, thus regaining pigmentation in affected individuals. Despite the widespread use of NBUVB in secondary and tertiary clinics in India, the status of melanocyte stem cells and immune cells, pre-and post-NBUVB is not well understood. We observe that following NBUVB phototherapy, melanocyte stem cells (pax3+) re-populate the epidermis and express melanogenesis markers (Tyrosinase, Trp2, kit) concomitant with a decrease in CD3+ T-cells within the skin. Our study reaffirms the therapeutic efficacy of NBUVB in promoting re-pigmentation in an Indian cohort of vitiligo patients. Further, NBUVB is effective in reducing overall immune load, widely considered a major contributor to the pathogenesis of the disease.

cell biology↗

bioRxiv2024

ALTering cancer by triggering telomere replication stress through the stabilization of promoter G-quadruplex in SMARCAL1

Most of the human cancers are dependent on telomerase to extend the telomeres. But [~]10% of all cancers use a telomerase-independent, homologous recombination mediated pathway called alternative lengthening of telomeres (ALT). Due to poor prognosis, the ALT status is not being considered yet in the diagnosis of cancer. No such specific treatment is available till date for ALT cancers. ALT positive cancers are dependent on replication stress to deploy DNA repair pathways to the telomeres to execute homology recombination mediated telomere extension. SMARCAL1 (SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like 1) is associated with the ALT telomeres to resolve replication stress thus providing telomere stability. Thus, the dependency on replication stress regulatory factors like SMARCAL1 made it a suitable therapeutic target for the treatment of ALT positive cancers. In this study, we found a significant downregulation of SMARCAL1 expression by stabilizing the G-quadruplex (G4) motif found in the promoter of SMARCAL1 by potent G4 stabilizers, like TMPyP4 and BRACO-19. SMARCAL1 downregulation led towards the increased localization of PML (promyelocytic leukaemia) bodies in ALT telomeres and triggered the formation of APBs (ALT-associated promyelocytic leukaemia bodies) in ALT positive cell lines, thus increasing telomere replication stress and DNA damage at genomic level. Induction of replication stress and hyper recombinogenic phenotype in ALT cells mediated by G4 stabilizing molecules already highlighted their possible application as a new therapeutic window to target ALT-positive tumors. In accordance with this, our study will also provide a valuable insight towards the development of G4 based ALT-therapeutics targeting SMARCAL1.

biochemistry↗

bioRxiv2023

A Pose-Informed De-Noising Diffusion Model for Adult Naturalistic EEG Signals

Artifact contamination in EEG (electroencephalogram) signals is a significant problem, especially in naturalistic settings where participants can move freely. This contamination stems from various sources like eye movements, muscle activity, sweat, and electrical interference, whose effects differ greatly from each other. Traditional denoising methods, such as Independent Component Analysis, are limited because they assume a linear relationship between the source of the artifacts and the EEG signals, and often require the dominance of one noise source over others. Moreover, these methods need expert knowledge in EEG analysis and lack an objective standard for evaluation. To overcome these challenges, we propose two innovations: Firstly, we introduce the use of "video-estimated" pose coordinates - the x and y positions of different body points (like wrists, eyes, and ankles) - to assist in the EEG denoising process. Secondly, we present a denoising diffusion model, EEG-DDM, that utilizes both the contaminated EEG signals and these pose coordinates to effectively denoise the EEG. Our findings show that incorporating keypoints (pose coordinates) improves denoising performance and helps maintain cross-spatial dependencies in the data. Additionally, we enhance human interpretability of the process by displaying saliency maps generated by our model, which explain the contributions of these keypoints in the denoising process.

neuroscience↗