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Biswas, S.

Publications and source records attributed to Biswas, S..

At least 55 records · Page 3Linked to original sources

A High-throughput Multi-Species Platform Using Biolayer Interferometry Immunosorbent Assay (BLI-ISA) as an Alternative to Indirect ELISA for Vaccine Development

In vaccine development, the ELISA (Enzyme-Linked Immunosorbent Assay) is commonly used to compare the antibody titers of samples from several treatment groups. This often requires extensive sample preparation, manual labor, and long incubation and processing times. Biolayer Interferometry (BLI) has emerged as an alternative to the ELISA for the detection and quantification of antigen-specific antibodies in biological samples. However, the implementation of BLI as a replacement for the ELISA in vaccine development requires that experimental parameters are established for accurate and reproducible results. Here we give a general protocol for a biolayer interferometry immunosorbent assay (BLI-ISA) for the comparison of antigen-specific antibody levels in treatment group sera that uses secondary antibody binding responses as replacement for ELISA endpoint titers. We also validate that this BLI-ISA yields the same results as the ELISA endpoint titer while requiring far less time and effort.

immunology↗

Pan-cancer prediction of tumor immune activation and response to immune checkpoint blockade from tumor transcriptomics and histopathology

Accurately predicting which patients will respond to immune checkpoint blockade (ICB) remains a major challenge. Here, we present TIME_ACT, an unsupervised 66-gene transcriptomic signature of tumor immune activation derived from TCGA (The Cancer Genome Atlas) melanoma data. First, we demonstrate that TIME_ACT scores accurately identify tumors with activated immune microenvironments across different cancer types. Further, analysis of spatial features reveals that tumor microenvironment regions with dense lymphocyte infiltration near tumor cells have high TIME_ACT scores, successfully marking localized immune activation. Second, across 25 transcriptomic ICB cohorts encompassing nine cancer types, TIME_ACT achieves a mean AUC of 0.76 and a mean odds ratio of 5.77, significantly outperforming 30 established transcriptomic signatures and prediction methods for ICB response, including a recently developed foundation model for immunotherapy response prediction. Third, we show that TIME_ACT scores can be accurately inferred from routine tumor histopathology slides and that slide-inferred TIME_ACT scores predict ICB response across nine new independent patient cohorts spanning eight cancer types, achieving a mean AUC of 0.72 and a mean odds ratio of 4.99. These findings establish TIME_ACT as a robust, pan-cancer biomarker that enables accurate, low-cost, and clinically scalable prediction of ICB response from routine histopathology.

cancer biology↗

Backbone Rigidity Encodes Universal Viscoelastic Signatures in Biomolecular Condensates

Biomolecular condensates exhibit a wide range of viscoelastic properties shaped by their molecular sequence and composition. Coarse-grained molecular models of intrinsically disordered proteins are widely used to complement experiments by revealing the structure and thermodynamics of condensates. However, fully flexible chain representations of inherently disordered proteins often fail to capture their complex viscoelastic behavior, instead predicting purely viscous responses. In this work, we demonstrate that introducing sequence-dependent chain rigidity enables the accurate reproduction of the elastic and viscous moduli for experimentally characterized condensates of A1-LCD and its numerous mutants. Furthermore, we show that the frequency-dependent loss factor can be described by a single parameter that universally correlates with viscosity across different sequences and variations of the coarse-grained molecular energy function. Our results also reveal that increased chain rigidity, indicated by a larger gyration radius, expands the condensates elastic regime. Finally, we elucidate the microscopic origins of sequence-encoded viscoelasticity by showing how it can be tuned through sequence rearrangements that promote sticker cluster formation.

biophysics↗

De novo design of hundreds of functional GPCR-targeting antibodies enabled by scaling test-time compute

We present significant advances in de novo antibody design against G protein-coupled receptors (GPCRs) enabled by scaling the test-time compute used by our generative protein design system, JAM. We de novo design hundreds of VHH (single domain) antibodies against CXCR4 and CXCR7, with top designs showing picomolar to low-nanomolar affinities, high selectivity, and favorable early-stage developability profiles, matching or outperforming clinical-stage molecules in these dimensions. Further, high affinity designs potently modulate receptor function, with most acting as antagonists (inhibitors) and, strikingly, a subset functioning as agonists (activators) of CXCR7 -- the first antibody agonists reported for this receptor, and the first computationally designed antibody GPCR agonists of any kind. Using a single experimentally validated agonist to further prompt JAM, we generate over 300 additional diverse agonists with superior properties, including a design with agonism EC50 rivaling that of CXCR7s natural ligand, SDF1. These results show that increasing the "reasoning" capacity of biomolecular generative models by scaling test-time computation will enable them to solve increasingly difficult problems in drug design.

synthetic biology↗

Hematopoietic Stem Cells Modulate Tumor Immune-Environment to Target Triple-Negative Breast Cancer via Altering Mitochondrial Bioenergetics

Ontogenic development of Hematopoietic stem cells (HSCs) takes place at diverse anatomical niches. Moreover, during embryonic development, HSCs migrate from the aorta-gonad mesonephros (AGM) to the fetal liver and finally to the bone marrow immediately after childbirth. Hence, the primary residence of adult HSCs in the bone marrow continues replenishing the hematopoietic lineage pool. In vivo, the HSC niche is significant and might be harnessed in regenerative medicine. HSCs in various niches have exhibited their respective tropism and proliferations based on the growth factors secreted by the niche. Accordingly, in this work, we hypothesized HSCs tropism towards cancer and stem cell niche of triple-negative breast cancer (TNBC) and HER2+, having a high relapse rate for possible cell therapy development. Our results indicate that HSC exclusive tropism towards breast cancer stem cells (CSC) and interaction with the cancer milieu lead to HSC differentiation into T-lymphocyte cells (CD4 & CD8). Moreover, the single-cell type proteomics of the migrated HSCs towards TNBC-CSCs and HER2+ cells indicated upregulation of IL-7 and Notch protein and several other upregulated proteins primarily involved in T cell activation and migration-related pathways. Likewise, the metabolomics from HSCs-derived conditioned media-treated CSCs, and HER2+ cells showed the capability of HSC-CM in arresting the growth and cell cycle of TNBC-CSC via altered mitochondrial bioenergetics. Hence, this study paves the way toward harnessing the potential of both HSCs and HSC-CM for personalized medicine against TNBC CSCs. HighlightsO_LIHematopoietic stem cells exhibited tumor tropism towards triple negative breast cancer stem cells and HER2+ cancer cells. C_LIO_LIUpon migration in the tumor milieu, HSCs differentiated into T cells, targeted CSCs, and modulated the upregulation of interleukin-7 and notch proteins. C_LIO_LIHSCs-CM inhibited the cell cycle in TNBC-CSCs by downregulating CDK1, disrupting mitochondrial bioenergetics via upregulated Drp1, and inducing CSC apoptosis. C_LIO_LIParacrine signaling from HSCs via conditioned media induced metabolic stress and disrupted key metabolic pathways in TNBC-CSCs. C_LI SummaryHematopoietic stem cells (HSCs) are known for their regenerative potential in the blood system. This study reveals the novel therapeutic potential of hematopoietic stem cells (HSCs) in combating triple-negative breast cancer stem cells (TNBC-CSCs). HSCs exhibited tropism towards TNBC-CSCs, themselves differentiated into T cells within the tumor microenvironment, leading to targeted cell killing of TNBC-CSCs. In addition, paracrine signaling from HSC-conditioned media (CM) induced metabolic stress in TNBC-CSCs and disrupted key metabolic pathways. HSC-CM also disrupted mitochondrial dynamics and function, leading to DNA damage and apoptosis. Critically, HSC-CM impaired TNBC-CSC stemness by downregulating stemness genes, leading to the inhibition of 3D spheroid formation. Hence, our study highlights HSCs as a promising therapeutic strategy for targeting TNBC-CSCs via disrupted metabolic homeostasis and self-renewal.

cancer biology↗

Liver biopsies obtained throughout SIV infection reveal evolving interferon stimulated protein expression within distinct monocyte/macrophage subsets

ABSTRACTLiver dysfunction is more common and more severe among people with HIV than in the general population. Our previous transcriptomic analysis identified an increased hepatic type-1 interferon (IFN-1) response in simian immunodeficiency virus (SIV) infected rhesus macaques, including pronounced upregulation of the IFN-1 stimulated gene product MX1. Here, we interrogated the role of different cell types in the IFN-1 response, focusing on macrophage subsets. During the acute phase of SIV infection, the expression of MX1 in liver biopsies was elevated in the resident macrophage Kupffer cells (KCs, CD163+ CD206+) as well as liver sinusoidal endothelial cells (LSECs, CD163- CD206+). Chronic infection was associated with increased MX1 expression both within KCs and the recruited monocyte-derived macrophages (MdMs, CD163+ CD206-) although the KCs were associated with the highest MX1 expression levels. We explored factors in the liver potentially associated with the macrophage IFN-1 response: 1) SIV DNA load, 2) bacterial DNA load (assessed via SIV DNA and 16S bacterial DNA qPCR, respectively), and 3) acute-phase hepatocyte lipid accumulation (steatosis). Both SIV and bacteria were elevated during chronic infection and directly correlated with MdM frequency. KC frequency did not correlate with SIV load but inversely correlated with bacterial load and also correlated directly with hepatocyte microvesicular steatosis in acute infection. Hepatocytes expressed variable levels of MX1 during acute and chronic infection. Overall, our data identify MdMs, LSECs and KCs as contributors to the heightened expression of MX1 in the liver during SIV infection. KCs express the highest levels of MX1 and therefore represent a potential target to reduce liver inflammation in people with HIV. AUTHOR SUMMARYLiver disease disproportionately affects people with HIV (PWH). However, liver biopsies are generally not indicated in humans, making the immune mechanisms underlying HIV-driven liver dysfunction difficult to study. Using a model of HIV infection in which rhesus macaques are infected with SIV, we previously found a strong upregulation of type 1 interferon (IFN-1) signaling as well as an increased number of CD68+ monocyte/macrophage cells in the liver during chronic infection. Here we used longitudinally collected liver biopsies from SIV-infected macaques to describe the kinetics of the IFN-1 response, focusing on MX1, which was a top differentially expressed gene in our previous transcriptomic screen. We also defined two populations of liver macrophages - resident Kupffer cells and recruited monocyte-derived macrophages - to identify which cells produce MX1, what stimuli the cells respond to, and where the cells accumulate within the liver. Our results indicate that Kupffer cells are the major producers of MX1 during acute and chronic infection and that their frequency in the liver correlates with lipid accumulation (steatosis) during acute infection. These data provide insights into how Kupffer cells may promote inflammation and fibrosis and identify Kupffer cells as an important target to limit liver disease in PWH.

immunology↗

Role of Dengue in SARS-CoV-2 Evolution in Dengue Endemic Regions

Evidence suggests that dengue virus (DV) antibodies (Abs) and SARS-CoV-2 Abs were cross-reactive, resulting in reciprocal serological cross-interaction and providing cross-protection in populations in co-endemic regions. It became apparent from the present study that SARS-CoV-2 variants were preferentially selecting mutation(s)/deletions in the spike to evade interaction with DV Abs. We looked at mutations in the SARS-CoV-2 spike protein and how they affected the antigenicity, focusing on successively emergent major variants such as B.1.1.7 (Kent), B.1.617 (Delta), B.1.617.2.1 (Delta-Plus), B.1.1.529 (Omicron-BA.1) and B.1.1.529 (Omicron-BA.2). To further understand the effect of cross-reactive DV Abs on SARS-CoV-2 spike mutation(s), structural studies and docking simulations were performed using DV-2 envelope (E) Abs. Signature mutation (s) in spike variants implied that majority of the above changes in the spike were driven by DV Abs rather than immune pressure of SARS-CoV-2 (preceding variants). This was supported by the fact that the lately emergent SARS-CoV-2 variants like Omicrons (2022-23) were at least 50% less cross-reactive to DV compared to preceding predominant strains. This was further supported by the observed cross-binding of pre-pandemic DV Ab-positive serums to spike synthetic peptides in ELISA, designed from certain regions of the spike RBD which showed maximum cross-interactions with DV E Abs.

microbiology↗

Isl1 Controls Axon Pathfinding of Retinal Ganglion Cells in the Binocular Visual Pathway

Axons of retinal ganglion cells (RGCs) face a choice to project ipsilaterally or contralaterally at the optic chiasm. This decision is crucial for the establishment of binocular vision in mammals. The transcription factor ZIC2 is well known as a key determinant of ipsilateral RGC identity, however the transcriptional programs controlling contralateral RGC identity have only begun to be elucidated more recently. Here we show that inactivation of the LIM-HD transcription factor ISL1 results in an expansion of the ZIC2+ ventrotemporal (VT) domain of the retina and an increase in ipsilateral projections from outside the VT retina. RNA-Seq, gene expression and CUT&Tag analyses show that ISL1 regulates RGC laterality through a set of unique downstream effectors as well as a few common ones, as other transcription factors. Our data also show that RGC axons misrouted at the midline in Isl1-null mutants could innervate the appropriate eye-specific regions of the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC), in agreement with earlier studies that have shown that eye specific targeting of visual nuclei in the brain is independent of laterality decisions at the optic chiasm.

neuroscience↗

Robust Prediction of Patient-Specific Cancer Hallmarks Using Neural Multi-Task Learning: a model development and validation study

BackgroundAccurate quantification of cancer hallmark activity is essential for understanding tumor progression, tailoring treatments, and improving patient outcomes. Traditional methods, such as histopathological grading and immunohistochemistry for protein expression, often overlook the complex interplay between cancer cells and the tumor microenvironment and provide limited insight into hallmark-specific mechanisms. We aimed to develop OncoMark, a high-throughput deep learning-enabled neural multi-task learning framework capable of systematically quantifying integrative hallmarks activities using transcriptomics data from routine tumor biopsies. MethodsIn this study, we acquired single-cell transcriptomics data from 941 tumor samples across 14 tissue types, comprising nearly 3.1 million cells from 56 studies conducted worldwide, to form a large multicenter dataset. Our model employs a supervised neural multi-task learning method designed to predict multiple cancer hallmarks present in the biopsy samples simultaneously. The OncoMark model was developed and tested on 90% of the studies (patients from 51 studies) using repeated five-fold cross-validation performed twice. For further evaluation, the model was assessed on the remaining 10% of the studies (patients from 5 studies) that were excluded from the initial training and testing dataset. Additionally, we included patients from publicly available datasets, including TCGA, GTEx, ANTE, MET500, POG570, CCLE, TARGET, and PCAWG to validate the models performance. The primary objective was to evaluate the performance of the model in identifying cancer hallmarks in cancer datasets and ensure no hallmark predictions were made in normal samples across the four prespecified groups: (i) internal test set, (ii) external test set, (iii) normal samples (real-world), and (iv) cancer samples (real-world). FindingsOncoMark demonstrated exceptional performance in predicting cancer hallmark states, achieving near-perfect accuracy across internal test data and five external test datasets. Internal testing consistently showed accuracy, precision, recall, and F1 scores exceeding 99%, underscoring the models reliability across hallmarks. External test further confirmed these findings, with accuracy, precision, recall, F1 scores, and balanced accuracy consistently exceeding 96{middle dot}6%, and multiple datasets achieving perfect scores, highlighting the models exceptional generalizability and robustness. Specificity tests using GTEx and ANTE datasets accurately classified normal tissues, while sensitivity analysis on TCGA, MET500, CCLE, TARGET, PCAWG, and POG570 datasets effectively identified cancer hallmarks. InterpretationWe developed an AI-based framework that enables accurate, efficient, and cost-effective quantification of cancer hallmark activity directly from transcriptomics data. The framework demonstrated significant potential as an assistive tool for guiding personalized treatment strategies and advancing the clinical management of cancer patients. FundingAshoka University, S.N. Bose National Centre for Basic Sciences, Mphasis F1 Foundation, DST SERB Core Research Grant. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSWe conducted an extensive literature search using Google Scholar and PubMed without language restrictions, employing search terms such as "(Predicting OR Classifying OR Annotating) and (cancer hallmarks) AND (Deep OR Machine Learning) OR (Artificial Intelligence OR AI)." While there have been advancements in molecular oncology and computational methodologies over the two decades since the concept of cancer hallmarks was first introduced, a comprehensive machine learning or deep learning framework to annotate all cancer hallmarks simultaneously from tumor biopsy samples remains to be developed. Additionally, the scarcity of hallmark-annotated datasets has posed a significant challenge, hindering the development of robust predictive models. Added value of this studyThis study introduces OncoMark, a novel high-throughput neural multi-task learning (N-MTL) framework designed to predict all cancer hallmark activities simultaneously from biopsy samples. OncoMark addresses the lack of annotated hallmark-specific data by generating synthetic biopsy (pseudo-bulk) datasets annotated with hallmark activity, meticulously modeled to reflect real-world tumor biology while maintaining clinical relevance. The framework employs a multi-task learning approach to capture interdependencies among hallmarks, advancing beyond isolated predictions to offer a holistic view of tumor biology. Validation on five independent datasets comprising 95 patient samples demonstrated its generalizability and reproducibility. Further external validation using eight datasets, encompassing over 11,679 cancer and 8348 normal patient samples, reinforced its robustness. To promote clinical integration, a user-friendly web-based tool was developed, enabling seamless access for oncologists and researchers. Implications of all the available evidenceThe OncoMark framework represents a transformative advancement in cancer diagnostics and treatment planning. By enabling accurate and reproducible prediction of all hallmark activities simultaneously from biopsy samples, this model paves the way for precision oncology at scale. Its ability to systematically capture hallmark interdependencies provides deeper insights into tumor behavior, guiding the development of individualized targeted therapies. The incorporation of a web-based interface ensures the accessibility of this innovation to clinicians worldwide, bridging the gap between computational oncology and clinical practice. Following further validation and integration into healthcare workflows, OncoMark has the potential to improve cancer outcomes by delivering timely, cost-effective, and precise tumor analyses, facilitating informed therapeutic decision-making with unparalleled precision. Cancer progression is driven by a set of well-defined biological principles--collectively termed the "hallmarks of cancer"--yet current diagnostic approaches seldom incorporate these distinct molecular features into clinical practice. Despite substantial progress in molecular oncology, traditional methods like histopathological grading and immunohistochemical assays often fail to capture the complex interplay between cancer cells and the tumor microenvironment, emphasizing the need for robust computational frameworks capable of systematically quantifying hallmark-specific activity. Here, we address this gap by developing OncoMark, a high-throughput neural multi-task learning (N-MTL) framework designed to simultaneously quantify hallmark activities in tumor biopsies using transcriptomics data. We show that OncoMark achieves near-perfect accuracy, precision, recall, and F1 scores (>99%) in cross-validation, with external validation consistently exceeding 96.6% on five independent datasets. Further evaluation on eight additional datasets--including large-scale cancer cohorts (TCGA, MET500, CCLE, TARGET, PCAWG, POG570) and normal tissue datasets (GTEx, ANTE)--demonstrated high specificity for normal samples and robust sensitivity for hallmark prediction in cancer. By delivering a comprehensive and cost-effective molecular portrait of tumor biology and providing a user-friendly web platform accessible at https://oncomark-ai.hf.space/, OncoMark has the potential to guide tailored treatment strategies and advance precision oncology. More broadly, this framework signifies a transformative step toward routine hallmark-based diagnostics, promising to improve patient outcomes by facilitating timely and precise tumor profiling.

cancer biology↗

Canalization of circuit assembly by δ-protocadherins in the zebrafish optic tectum

Neurons are precisely and reproducibly assembled into complex networks during development. How genes collaborate to guide this assembly remains an enduring mystery. In humans, large numbers of genes have been implicated in neurodevelopmental disorders that are characterized by variable and overlapping phenotypes. The complexity of the brain, the large number of genes involved and the heterogeneity of the disorders makes understanding the relationships between genes, development and neural function challenging. Waddington suggested the concept of canalization to describe the role of genes in shaping developmental trajectories that lead to precise outcomes1. Here, we show that members of the {delta}-protocadherin family of homophilic adhesion molecules, Protocadherin-19 and Protocadherin-17, contribute to developmental canalization of visual circuit assembly in the zebrafish. We provided oriented visual stimuli to zebrafish larvae and performed in vivo 2-photon calcium imaging in the optic tectum. The latent dynamics resulting from the population activity were confined to a conserved manifold. Among different wild type larvae, these dynamics were remarkably similar, allowing quantitative comparisons within and among genotypes. In both Protocadherin-19 and Protocadherin-17 mutants, the latent dynamics diverged from wild type. Importantly, these deviations could be averaged away, suggesting that the loss of these adhesion molecules leads to stochastic phenotypic variability and introduced disruptions of circuit organization that varied among individual mutants. These results provide a specific, quantitative example of canalization in the development of a vertebrate neural circuit, and suggest a framework for understanding the observed variability in complex brain disorders.

neuroscience↗

De novo design of epitope-specific antibodies against soluble and multipass membrane proteins with high specificity, developability, and function

We present JAM, a generative protein design system that enables fully computational design of antibodies with therapeutic-grade properties for the first time. JAM generates antibodies de novo in both single-domain (VHH) and paired (scFv/mAb) antibody formats that achieve double-digit nanomolar affinities, strong early-stage developability profiles, and precise epitope targeting without experimental optimization. We demonstrate JAMs capabilities across multiple therapeutic contexts, including the first fully computationally designed antibodies to multipass membrane proteins - Claudin-4 and CXCR7. Against SARS-CoV-2, JAM-designed antibodies achieved sub-nanomolar pseudovirus neutralization potency, with early stage developability metrics achieving established clinical benchmarks. We show that increasing test-time computation by allowing JAM to iteratively introspect on its outputs substantially improves both binding success rates and affinities, representing the first evidence that test-time compute scaling may extend to physical protein design systems. The entire process from design to recombinant characterization requires <6 weeks, and multiple targets can be pursued in parallel with minimal additional experimental overhead. These results establish de novo antibody design as a practical approach for therapeutic discovery, offering paths to both improved efficiency in standard workflows and new opportunities for previously intractable targets. Disclaimer: While we provide detailed descriptions of experimental methods and success metrics, we choose not disclose methodological details of JAM for commercial reasons.

bioengineering↗

Identification of Evolutionary Trade-Offs Associated with High-Level Colistin Resistance in Acinetobacter baumannii

ABSTRACTColistin (COL) belongs to the polymyxin group of drugs which possesses a positive charge and interacts with lipopolysaccharide (LPS) of Gram-negative bacterial outer membrane. Additionally, it can penetrate the cell membrane and disrupt the integrity of the phospholipid leading to cell death. Resistance against COL has been reported in Acinetobacter baumannii, a bacteria in the ESKAPE group of priority pathogens of the World Health Organization. Multiple and pan-drug-resistant strains of A. baumannii are rising in many medical facilities and they are becoming resistant to last-resort antibiotics including colistin. Though plasmid-encoded acquisition of mcr-1 has been associated with clinical resistance, drug efflux, complete loss of LPS by inactivation of the biosynthetic pathway (lpxACD), and modifications of target LPS by-products of chromosomal pmrCAB genes has been ascribed with resistance evolution against COL. To further delve into the evolutionary dynamics of COL-resistance here we report experimental evolution of extreme COL-resistance by adaptive evolution of the reference strain A. baumannii ATCC19606. Phenotypic characterization has been performed for the evolved strains, which demonstrated hyperbiofilm phenotype and striking decrease in fitness. A comprehensive antibiotic susceptibility profiling has been performed on the evolved strains. Whole genome sequencing of the resistant strains led to the identification of mutations prospectively associated with COL resistance. Phenotypic characterization of three COL-resistant clinical isolates of A. baumannii revealed similarity with experimentally evolved resistant mutants at least in one of the isolates.

microbiology↗

Interaction between native and prosthetic visual responses in optogenetic visual restoration

Degenerative retinal disorders leading to irreversible photoreceptor death are a common cause of blindness. Optogenetic gene therapy aims to restore vision in affected individuals by introducing light sensitive opsins into the surviving neurons of inner retina. While up until now the main focus of optogenetic therapy has been on terminally blind individuals, treating at stages where residual native vision is present could have several advantages. Yet, it is still unknown how residual native and optogenetic vision would interact if present at the same time. Using transgenic mice expressing the optogenetic tool ReaChR in ON-bipolar cells, we herein examine this interaction through electroretinography (ERG) and visually evoked potentials (VEP). We find that optogenetic responses show a peculiar ERG signature and are enhanced in retinas without photoreceptor loss. Conversely, native responses are dampened in the presence of ReaChR. Moreover, in VEP recordings we find that optogenetic responses reach the cortex asynchronous to the native response. These findings should be taken into consideration when planning future clinical trials and may direct future preclinical research to optimize optogenetic approaches for visual restoration. The identified ERG signatures moreover may serve to track treatment efficiency in clinical trials.

neuroscience↗

Erythrocytic plasma membrane calcium ATPase (PMCA4b) variations mediate redox imbalance to determine artemisinin sensitivity in malaria

Artemisinin resistance in Plasmodium falciparum remains a major public health challenge for the ongoing malaria elimination programs. Till now, artemisinin resistance is linked with the variations in the genome of P. falciparum which are mainly clustered in the Pfkelch13 gene. Several studies reported artemisinin resistance in the malaria endemic areas without finding any evidence of genetic variation in parasite for this occurrence. This study interrogated whether host genetic variations have any association with artemisinin sensitivity of malaria parasite. We investigated the relationship of 1) genetic variations in the human ATP2B4 gene and 2) the resultant surface expression of plasma membrane calcium ATPase (PMCA4b) with the intraerythrocytic levels of calcium, reactive oxygen species (ROS) and the resistance towards artemisinin in the intraerythrocytic parasite. This study found negative correlation of PMCA4b expression level with intraerythrocytic calcium and ROS levels. Further in-vitro growth assays revealed that artemisinin sensitivity is reduced in the parasites growing within the RBCs having low PMCA4b and high oxidative stress. Overall, this study highlights the strong association of host PMCA4b in cellular calcium mediated redox imbalance, which significantly contributes to artemisinin resistance in malaria parasite. Hence, this is the first study to document the effect of host variations on artemisinin sensitivity of the parasite. We further emphasize that many redox modulating RBC polymorphisms that are prevalent in malaria endemic areas could influence artemisinin resistance and can serve as potential biomarkers for predicting therapeutic response. Thus, detailed population specific research may provide new insights for personalized malaria treatment and may inform future drug development strategies. SignificanceThe human host and malaria parasite share a closely interconnected relationship hence host variations could influence parasite drug resistance. This study demonstrates that reduced PMCA4b expression, the primary calcium efflux pump in RBCs, significantly increases the erythrocytic calcium and reactive oxygen species (ROS) levels, thereby decreasing the P. falciparum growth as well as artemisinin sensitivity. Many ROS inducing RBC polymorphisms, such as sickle cell, thalassemia, G6PD deficiency, PMCA4b variations etc. have emerged as strong malaria protective traits in several studies in malaria endemic areas. But these traits could also influence artemisinin resistance and can serve as potential biomarkers for predicting therapeutic response and highlights the importance of host erythrocytes oxidative microenvironment surveillance in monitoring antimalarial drug resistance.

microbiology↗

Assessing the efficacy of therapeutically promising combination of polymyxin B and triclosan against colistin resistant Klebsiella pneumoniae

Antimicrobial resistance (AMR) is one of the greatest public health challenges of the current time, and it is primarily associated with Gram-negative bacterial infections. Among these infections, Klebsiella pneumoniae is the most notorious bacterial pathogen in the context of AMR dissemination. In this dire circumstance, clinicians explored old regimes such as colistin to treat these multidrug-resistant infections; however, unfortunately, the resistance towards these last-resort drugs is also emerging rapidly. In this study, we examined the occurrence of colistin resistance in K. pneumoniae concerning its mechanism of resistance, chronology, and geographical distribution. We found that resistance towards these last-resort drugs, colistin and polymyxin B, is emerging rapidly, with evolving multiple mechanisms of resistance. While efforts continue to develop new antibacterial drugs, a combination of approved antibacterial drugs may be one of the most suitable strategies to fight against AMR in the current time-ticking situation. In this series, we evaluated the efficacy of a therapeutically viable combination of polymyxin B and triclosan using a set of standard antibacterial assays, used for in vitro preclinical efficacy. We found that the combination is highly effective in colistin-resistant clinical strains of K. pneumoniae, as triclosan sensitizes the pathogen towards polymyxin B. Furthermore, the results of additional complementary experiments, such as time-kill kinetics, biofilm inhibition, frequency of resistance, cell viability, and cytotoxicity assays, show very encouraging results for the feasibility and validation of this combination. Finally, we examined the presence of mutations in field isolates of K. pneumoniae FabI enzyme, as it has been hypothesized previously that triclosan may cause mutation in its binding target, FabI. Interestingly, we could not detect any mutation in the triclosan binding site of FabI in the genome of field isolates. Altogether, this study provides an overview of the current situation on colistin resistance, a promising solution for colistin resistance comprising a combination of two already being used antibacterial ingredients based on in vitro efficacy studies.

microbiology↗

Comprehensive Enumeration of Cancer Stem-like Cell Heterogeneity Using Deep Neural Network

Cancer stem cells (CSCs), a distinct subpopulation within tumors, are pivotal in driving treatment resistance and tumor recurrence, posing substantial challenges to conventional therapeutic strategies. Precise quantification and profiling of these cells are essential for improving cancer treatment outcomes. We present ACSCeND, an advanced deep neural network model accompanied by a robust workflow, specifically developed to quantify cellular compositions from bulk RNA-seq data, enabling accurate CSC profiling. By integrating bulk RNA-seq data with insights derived from single-cell RNA-seq datasets, ACSCeND effectively captures the diversity and hierarchical organization of tumor-resident cell states, alongside cell-specific gene expression profiles (GEPs). Compared to current tissue deconvolution models, ACSCeND exhibits superior performance, achieving significantly higher Concordance Correlation Coefficient (CCC) values and lower Root Mean Square Error (RMSE) across various pseudobulk and real-world bulk tissue samples. Application of ACSCeND to TCGA and PRECOG datasets reveals a strong association between CSC abundance and poorer disease-free survival outcomes, underscoring the clinical relevance of CSCs in cancer progression. Furthermore, cell-specific GEPs for distinct CSC states unveil novel molecular signatures and illuminate the origins of CSC-driven tumor heterogeneity. In summary, ACSCeND provides a powerful, scalable platform for high-throughput quantification of cellular compositions and distinct potency states within normal tissues as well as highly heterogeneous tissues, such as tumors.

genomics↗

Profiling Human iPSC-Derived Sensory Neurons for Analgesic Drug Screening Using a Multi-Electrode Array

Chronic pain is a major global health issue, yet effective treatments are limited by poor translation from preclinical studies to humans. To address this, we developed a high-content screening (HCS) platform for analgesic discovery using hiPSC-derived nociceptors. These cells were cultured on multi-well micro-electrode arrays to monitor activity, achieving nearly 100% active electrodes by week two, maintaining stable activity for at least two weeks. After maturation (28 days), we exposed the nociceptors to various drugs, assessing their effects on neuronal activity, with excellent assay performance (Z values >0.5). Pharmacological tests showed responses to analgesic targets, including ion channels (Nav, Cav, Kv, TRPV1), neurotransmitter receptors (AMPAR, GABA-R), and kinase inhibitors (tyrosine, JAK1/2). Transcriptomic analysis confirmed the presence of these drug targets, although expression levels varied compared to primary human dorsal root ganglion cells. This HCS platform facilitates the rapid discovery of novel analgesics, reducing the risk of preclinical-to-human translation failure. MotivationChronic pain affects approximately 1.5 billion people worldwide, yet effective treatments remain elusive. A significant barrier to progress in analgesic drug discovery is the limited translation of preclinical findings to human clinical outcomes. Traditional rodent models, although widely used, often fail to accurately predict human responses, while human primary tissues are limited by scarcity, technical difficulties, and ethical concerns. Recent advancements have identified human induced pluripotent stem cell (hiPSC)-derived nociceptors as promising alternatives; however, current differentiation protocols produce cells with inconsistent and physiologically questionable phenotypes. To address these challenges, our study introduces a novel high-content screening (HCS) platform using hiPSC-derived nociceptors cultured on multi-well micro-electrode arrays (MEAs). The "Anatomic" protocol, used to generate these nociceptors, ensures cells with transcriptomic profiles closely matching human primary sensory neurons. Our platform achieves nearly 100% active electrode yield within two weeks and demonstrates sustained, stable activity over time. Additionally, robust Z factor analysis (exceeding 0.5) confirms the platforms reliability, while pharmacological validation establishes the functional expression of critical analgesic targets. This innovative approach improves both the efficiency and clinical relevance of analgesic drug screening, potentially bridging the translational gap between preclinical studies and human clinical trials, and offering new hope for effective pain management.

neuroscience↗

Tau accelerates tubulin exchange in the microtubule lattice

Microtubules are cytoskeletal filaments that exhibit dynamic tip instability and, as recent discoveries reveal, possess a dynamic lattice undergoing continuous tubulin loss and incorporation. In this study, we investigate the role of tau, a neuronal microtubule-associated protein (MAP) known for its stabilizing effects on microtubules, in modulating lattice dynamics. Using in vitro reconstitution, kinetic Monte Carlo modeling, and molecular dynamics simulations, we reveal that tau, despite lacking enzymatic activity, accelerates tubulin exchange within the lattice, particularly at topological defect sites. Tau appears to stabilize longitudinal tubulin-tubulin interactions while destabilizing lateral ones, thereby enhancing the mobility and repair of lattice defects. These results challenge the traditional view of tau as merely a stabilizer, uncovering its active role in dynamically modulating microtubule lattice structure.

biophysics↗