Biology subjects

Sharma, R.

Publications and source records attributed to Sharma, R..

At least 109 records · Page 6Linked to original sources

bioRxiv2025

Hyaluronic Acid-Coated Melt Electrowritten Scaffolds Promote Myoblast Attachment, Alignment, and Differentiation

PurposeIn muscle tissues, anisotropic cell alignment is essential for optimal muscle fiber development and function. Biomaterials for muscle tissue engineering must guide cellular alignment while supporting cell proliferation and myogenic differentiation. MethodsHere, we describe the fabrication of a tissue-engineered construct consisting of a scaffold of aligned poly({varepsilon}-caprolactone) (PCL) microfibers coated in a dynamic covalent hydrazone crosslinked hyaluronic acid (HA) hydrogel to support myoblast attachment, myoblast alignment, and myotube formation. Norbornene modification of HA further enabled functionalization with fibronectin-derived arginine-glycine-aspartic acid (RGD) peptide. Scaffolds were fabricated using melt electrowriting (MEW), a three-dimensional (3D)-printing technique that uses stabilization of fluid columns to produce precisely aligned polymeric microfibers. We evaluated C2C12 mouse skeletal myoblasts cultured on non-coated, HA-coated, and HA-RGD-coated MEW scaffolds with fiber diameters of 10 {micro}m, 20 {micro}m, and 30 {micro}m using immunocytochemistry and creatine kinase activity assays. We further evaluated the mechanical properties of 20 {micro}m fiber scaffolds and their effect on myogenic gene expression and alpha-actinin protein expression of C2C12 myoblasts undergoing differentiation. ResultsHA-coated and HA-RGD-coated scaffolds increased attachment of C2C12 myoblasts on all fiber diameters compared to non-coated scaffolds, with HA-RGD-coated scaffolds demonstrating the highest cell attachment. All scaffolds supported cellular alignment along the fibers. Cells differentiated on scaffolds showed anisotropic alignment with increased myotube formation on HA-coated and HA-RGD-coated scaffolds as demonstrated by myosin heavy chain (MHC) staining and by the presence of striations on HA-coated scaffolds visualized with alpha-actinin staining. Increased creatine kinase activity and myogenic gene expression on day 5 further indicated myotube formation on all scaffolds, with HA-coated scaffolds significantly increasing the expression of several key myogenic markers. ConclusionThis unique combination of tunable biophysical and biochemical cues enables the creation of a biomimetic tissue engineered scaffold, providing a platform for new therapeutic approaches for muscle regeneration.

bioengineering↗

bioRxiv2025

Transcriptomic plasticity is a hallmark of metastatic pancreatic cancer

Metastasis is the leading cause of cancer deaths; nonetheless, how tumor cells adapt to vastly different organ contexts is largely unknown. To investigate this question, we generated a transcriptomic atlas of primary tumor and diverse metastatic samples from a patient with pancreatic ductal adenocarcinoma who underwent rapid autopsy. Unsupervised archetype analysis identified both shared and site-specific gene programs, including lipid metabolism and gastrointestinal programs prevalent in peritoneum and stomach wall lesions, respectively. We developed a probabilistic approach for inferring clonal phylogeny from single-cell and matched whole-exome data. Distantly related genetic clones in the peritoneum express the lipid metabolism program, likely due to signaling by the adipocyte-rich peritoneum environment, and cells in most clones express multiple programs, suggesting that transcriptomic plasticity is a prevalent feature of metastatic cells. These deeply annotated analyses using a patient-centric platform provide a model for investigating metastatic mechanisms and plasticity in advanced cancer.

bioinformatics↗

bioRxiv2025

Joint linear modeling of transcriptomics and proteomics is predictive of cancer metastasis

A central goal of conducting omics measurements is to understand how molecular features inform higher-order cell- and tissue-level phenotypes. In particular, multi-omics offers insights into how information encoded by the genome is coordinated through biological layers, resulting in functional outputs1. Due to myriad post-transcriptional regulatory processes, the coordination between mRNA and protein cannot be simply reduced to gene-wise correlation. Yet, both modalities have been shown to serve as representations of biological state, and multi-omics integration has been used to improve these representations. Multi-omics approaches typically do not focus on how mRNA and protein features coordinate, but rather use the additional information for improved prediction or feature selection. Here, instead, we showed that standard linear machine learning models provide an understanding of transcriptomic and proteomic coordination in the context of a biological phenotype of interest, in this case cancer metastasis. We find that, in the context of metastasis, a select subset of proteomic features--reflecting a more concentrated signal relative to the broadly distributed transcriptomic signal--offers additional information to that encoded by transcriptomics, as demonstrated by improved model performance when integrating the two modalities and the relative feature importance of proteomics. Top features show a depletion of gene-product overlap across modalities, indicating that the model primarily leverages instances in which the two modalities are providing complementary information with respect to phenotype. However, in instances when both modalities are selected for a given gene product, there is high information consistency that synergistically bolsters phenotype prediction. Altogether, by using model fits that relate both modalities to phenotype, we observe a nuanced coordination of protein and mRNA, in which both modalities tend to provide consistent information about phenotype, yet benefits remain to incorporating a combination of both complementary and reinforcing signals across modalities.

systems biology↗

bioRxiv2025

Utilizing Genomics to Identify Novel Immunotherapeutic Targets in Multiple Myeloma High-Risk Subgroups

Immunotherapy is now standard of care for multiple myeloma, where the most common targets are B cell maturation antigen, CD38, and G protein-coupled receptor class C group 5 member D but strategies to identify additional targets are needed. We have utilized two large datasets of genomic data and integrated them with existing databases to identify expressed cell surface targets in myeloma patients. Importantly, we also identify targets specific to genomic defined subgroups of patients including primary translocations and high-risk subgroups. Examples of subgroup targets include ROBO3 in t(4;14), CD109 in t(14;16), CD20 in t(11;14), GPRC5D in 1q+, and ADAM28 in biallelic TP53 samples. Expression was validated by flow cytometry and CRISPR-Cas9 knock out models. Sub-clonal differences in expression were noted, as was alternative splicing of existing immunotherapy targets such as FCRL5. These results highlight the use of genomic stratification to identify novel therapeutic targets. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=157 HEIGHT=200 SRC="FIGDIR/small/635544v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@6965e6org.highwire.dtl.DTLVardef@1a0e567org.highwire.dtl.DTLVardef@34fc30org.highwire.dtl.DTLVardef@98c3d4_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2025

Neuronal Decoding of Temperature Signals in Caenorhabditis elegans

Neural processing in animals facilitate sensory adaptation by eliciting appropriate responses to changing environmental stimuli. Although sensory adaptation is well recognized, the specific role of individual neurons in these adaptive mechanisms remains poorly understood from a theoretical standpoint. Specifically, it is unclear how single neurons influence the processing of sensory information and modulate their responses to environmental changes. In Caenorhabditis elegans (C. elegans), the primary AFD thermosensory neurons respond to external thermal stimuli incorporating experience-dependent temperature response thresholds. While extensive experimental studies have highlighted the functional features of the AFD neurons, mathematical understanding of their responses is still not well established. In this study, we develop a theoretical framework that captures how a single pair of AFD neurons encodes sensory information and regulates their responses to thermal warming signals, with a focus on how prior environmental experiences influence these responses. Through this framework we find that the interaction between two key entities i.e. cGMP and calcium, plays a crucial role in processing sensory information and fine-tuning neuronal responses to thermal changes. In addition to reproducing experimentally known trends, our results show that growth conditions such as cultivation temperature of the worms significantly shape the neurons functional properties, including their operating range, activation thresholds and response start time and duration. The findings in this work, therefore, enhance the overall understanding of how environmental experiences by single neuron shape sensory systems and provide a deeper connection between experimental data and quantitative models.

biophysics↗

bioRxiv2025

OcuPair, a novel photo-crosslinkable dendrimer-hyaluronic acid hydrogel bandage/bioadhesive for corneal injuries and temporary corneal repair

Traumatic corneal injuries are a leading cause of blindness among military personnel. These injuries need immediate attention at the combat zone, but treatment options are limited as life-saving measures are often prioritized. To address this critical gap, we have developed OcupairTM, a two-component hydrogel system that consists of (i) an injectable viscoelastic filler that stabilizes the ocular cavity and prevents hypotony. (ii) An in-situ photo-curable adhesive hydrogel comprising of methacrylated PAMAM dendrimer and hyaluronic acid engineered to form a transparent, flexible and robust bandage within 90 seconds, adhering to corneal surface and ensuring a water-tight seal securing full-thickness corneal wounds. Ex vivo studies demonstrated that the adhesive hydrogel is mechanically robust and withstands intraocular pressures beyond physiological range. In a rabbit corneal injury model, OcuPair effectively seals complex full thickness wounds and preserves the eye with favorable clinical outcomes for 5 days with no toxicity over 30 days. In this study, we have validated the pilot scale synthesis, formulation optimization, GMP scale-up and IDE-enabling GLP toxicity, essential for clinical translation as a battlefield-ready solution.

bioengineering↗

bioRxiv2024

The AMD-associated genetic polymorphism CFH Y402H confers vulnerability to Hydroquinone-induced stress in iPSC-RPE cells

Age-related macular degeneration (AMD), a degenerative disease of the macula, is caused by an interplay of diverse risk factors (genetic predisposition, age and lifestyle habits). One of the main genetic risks includes the Y402H polymorphism in complement Factor H (FH), an inhibitor of complement system activation. There has been, and continues to be, much discussion around the functional consequences of this Y402H polymorphism, whether the soluble FH protein confers its risk association, or if the cells expressing the protein themselves are affected by the genetic alteration. In our study, we examined the cell characteristics of the retinal pigment epithelium (RPE) cells, which play a major role in retinal homeostasis and stability and which are synonymously linked to AMD. Here, we employ RPE cells derived from induced pluripotent stem cells (iPSC) generated from donors, carrying either homozygous 402Y (low risk) or 402H (high risk) variants of the CFH gene. RPE cells were treated with Hydroquinone (HQ), a component of cigarette smoke, to induce oxidative damage. Intriguingly, RPE cells carrying high genetic risk proved more vulnerable to oxidative insult when exposed to HQ, as demonstrated by increased cytotoxicity, caspase activation, compared to the low-risk RPE cells. The exposure of RPE cells to RPE conditioned medium, normal human serum (NHS) and inactivated NHS (iNHS) had minimal impact on cell cytotoxicity and caspase activation, nor did the presence of purified soluble FH rescue the observed effects. This suggests that the degree of cellular susceptibility to oxidative stress is not conferred by soluble FH protein and other complement sources, but intercellularly because of the corresponding genetic risk predisposition. Considering the known connection of oxidative stress to proteotoxic stress and degrading processes, we investigated the unfolded protein response (UPR) and autophagy. When exposed to HQ, RPE cells showed an increase in autophagy markers, however iPSC-RPE cells carrying high genetic risk showed an overall reduced autophagic flux. Our data support the hypothesis that RPE cells carrying high genetic risk are less resilient to oxidative stress.

cell biology↗

bioRxiv2024

Identification of leaf rust resistance loci in hard winter wheat using genome-wide association mapping

Leaf rust, caused by Puccinia triticina (Pt), is a serious constraint to wheat production. Developing resistant varieties is the best approach to managing this disease. Wheat leaf rust resistance (Lr) genes have been classified into either all-stage resistance (ASR) or adult-plant resistance (APR). The objectives of this study were to identify sources of leaf rust resistance in contemporary U.S. hard winter wheat (HWW) and to dissect the genetic basis underlying leaf rust resistance in HWW. A panel of 732 elite HWW genotypes was evaluated for response to U.S. Pt races at the seedling stage and at the adult plant stage in leaf rust nurseries in Oklahoma, Texas, and Kansas. Further, the panel was genotyped using Multiplex Restriction Amplicon Sequencing (MRA-Seq) and DNA markers linked to the known ASR genes Lr18, Lr19, Lr21, Lr24, Lr37, and Lr42 and APR genes Lr34, Lr46, Lr67, Lr68, Lr77, and Lr78. Single nucleotide polymorphism (SNP) markers derived from MRA-Seq, DNA markers linked to the known Lr genes, and the phenotypic data were used for genome-wide association study (GWAS) to identify markers associated with leaf rust response. Gene postulation based on leaf rust reactions, DNA markers, and GWAS suggested the presence of Lr1, Lr2a, Lr10, Lr14a, Lr16, Lr18, Lr19, Lr21, Lr24, Lr26, Lr34, Lr37, Lr39, Lr42, Lr46, Lr68, Lr77, and Lr78 in the HWW panel. The GWAS identified 59 SNPs significantly associated with leaf rust response, of which 20 were likely associated with novel resistance loci and can be used to enhance wheat leaf rust resistance.

genomics↗

bioRxiv2024

Plant genotype and microbial strain combinations strongly influence the transcriptome under heavy metal stress conditions

Heavy metals such as cadmium (Cd) and mercury (Hg) pose significant threats to plant health and food safety as they are absorbed from the environment. Legumes are generally considered sensitive to heavy metals but possess standing genetic variation for accumulation and tolerance to toxic ions. We conducted a transcriptomic analysis on hydroponically and soil grown Medicago truncatula plants to investigate gene expression responses to Cd and Hg exposure in roots, leaves, and nodules. By using plant genotypes with varying metal tolerance or accumulation levels, we observed distinct clustering of gene ontologies, indicating tissue-specific, genotype-specific, and metal-specific gene expression patterns. Considering the symbiotic relationship between legumes and nitrogen-fixing bacteria, we further examined plant phenotypes and transcriptomes of plant genotypes with contrasting Hg accumulation levels and inoculated them with high or low Hg-tolerant Sinorhizobium medicae strains that have presence-absence variation for a mercury reductase (Mer) operon. Host plants inoculated with the Hg-tolerant rhizobia strain possessing a Mer operon exhibited less reduction in nodule number and plant biomass. A smaller reduction in iron (Fe) distribution in nodules after Hg stress was measured using X-ray Fluorescence (XRF) imaging. Dual transcriptome (host plant and bacteria) analysis of nodules revealed a remarkable decrease in the number of differentially expressed genes (DEGs) and clustering of gene ontologies in plants inoculated with the Hg-tolerant rhizobia strain, including symbiosis related genes. This suggests the Hg-tolerant rhizobia strain has the potential to mitigate Hg stress in host plants. Furthermore, we observed genotype-by-genotype interactions between the high Hg accumulating plant genotype and the Hg-tolerant rhizobia strain. These findings provide insights into enhancing plant resilience in contaminated environments through optimizing legume-rhizobia interactions for heavy metal tolerance, as well as identification of genetic mechanisms that can reduce transport to edible plant parts. HighlightsO_LIGenetic variation in tolerance to heavy metals affects responses in plant tissues C_LIO_LISymbiosis with Hg tolerant rhizobia strain reduced stress response in host plant C_LIO_LIDual-transcriptomics in nodules identified metal stress and symbiosis responses C_LIO_LIGenotype by genotype interaction significantly affected symbiosis gene expression C_LIO_LIRhizobia strain possessing Mer operon suggests genetic basis affecting responses C_LI

plant biology↗

bioRxiv2024

Oxytocin receptor controls distinct components of pair bonding and development in prairie voles

Oxytocin receptor (Oxtr) signaling influences complex social behaviors in diverse species, including social monogamy in prairie voles. How Oxtr regulates specific components of social attachment behaviors and the neural mechanisms mediating them remains unknown. Here, we examine prairie voles lacking Oxtr and demonstrate that pair bonding comprises distinct behavioral modules: the preference for a bonded partner, and the rejection of novel potential mates. Our longitudinal study of social attachment shows that Oxtr sex-specifically influences early interactions between novel partners facilitating the formation of partner preference. Additionally, Oxtr suppresses promiscuity towards novel potential mates following pair bonding, contributing to rejection. Oxtr function regulates coordinated patterns of gene expression in regions implicated in attachment behaviors and regulates the expression of oxytocin in the paraventricular nucleus of the hypothalamus, a principal source of oxytocin. Thus, Oxtr controls genetically separable components of pair bonding behaviors and coordinates development of the neural substrates of attachment.

neuroscience↗

bioRxiv2024

AyurPhenoClusters define common molecular roots for rare diseases and uncover ciliary dysfunctions in syndromic conditions

The heterogeneity of underlying causes and the variability of symptoms across Multiple organs in rare diseases present significant challenges when approached from an organ-centric perspective. Ayurveda, however, takes a multisystem perspective, assessing diseases through kinetic (Vata:V ), metabolic (Pitta:P ), and structural (Kapha:K ) dimensions, each with distinct phenotypic and molecular correlates. This study explores rare diseases from a systems perspective by integrating Ayurveda and unifying terminologies from both disciplines using Human Phenotype Ontology (HPO). Experts categorized 10,610 HPO terms into Ayurvedic phenotypic groups (V/P/K ) and applied the Expectation Maximization (EM) algorithm to cluster 12,678 diseases. This yielded six distinct clusters, termed AyurPhenoClusters, with 2,814 diseases uniquely classified and enriched for V/P/K phenotypes. Functional annotation of these, highlighted key biological processes: (i) embryogenesis and skeletal morphogenesis, (ii) endocrine and ciliary functions, (iii) DNA damage response and cell cycle regulation, (iv) inflammation and immune response, (v) immune function, hemopoiesis, and telomere aging, and (vi) small molecule metabolism and transport. Notably, the K predominant cluster had the highest ciliary gene enrichment (43%), followed by the V predominant cluster (16%), suggesting potential ciliopathies in V cluster. This systems-based approach enhances the understanding of rare diseases by bridging Ayurveda with modern medicine, for improved diagnostics and therapeutics

genetics↗

bioRxiv2024

Antimicrobial Potential and Characterization of Silver Nanoparticles Synthesized from Ocimum Sanctum Extract

The growing resistance of microbes to conventional antibiotics and the environmental impact of chemical synthesis methods highlight the urgent need for effective and sustainable antimicrobial agents. In this study, we address these challenges by synthesizing silver nanoparticles (AgNPs) using Ocimum sanctum leaf extract, a green and efficient method. We confirmed AgNPs synthesis through UV-vis spectroscopy, observing a Surface Plasmon Resonance (SPR) peak centered at 420 nm. X-ray Diffraction (XRD) analysis showed intense peaks at 37.81{degrees}, 45.01{degrees}, 63.91{degrees}, and 78.0{degrees}, corresponding to Braggs reflections at 111, 200, 220, and 311, respectively, with an average particle size of approximately 18 nm calculated using Scherrers formula. The reduction of Ag+ was monitored using Atomic Absorption Spectroscopy (AAS), which revealed a rapid decrease from 2.73 ppm to 0.023 ppm within four minutes, driven by the active reducing agents in the O. sanctum extract. The Scanning Electron Microscope (SEM) image confirmed the spherical shape of the AgNPs, with an average size of 23.82 {+/-} 4.17 nm. Fourier Transform Infrared (FTIR) spectroscopy identified absorption peaks at 1635 cm-1 and 3430 cm-1, associated with the amide I bond of proteins and OH stretching in alcohols and phenolic compounds, respectively. The synthesized AgNPs exhibited significant antimicrobial activity, demonstrated by a dose-dependent inhibitory effect against bacterial strains. The inhibition zone measured 6 mm at the lowest concentration of 5 {micro}g/L and increased progressively to 14 mm at the highest concentration of 25 {micro}g/L, indicating strong antimicrobial potential even at low dosages.

biochemistry↗

bioRxiv2024

New loci and candidate genes in spring two-rowed barley detected through meta-analysis of a field trial European network

This study contributes new knowledge on quantitative trait loci (QTLs) and candidate genes for adaptive traits and yield in two-rowed spring barley. A meta-analysis of a network of field trials, varying in latitude and sowing date, with 151 cultivars across several European countries, increased QTL detection power compared to single-trial analyses. The traits analysed were heading date (HD), plant height (PH), thousand-grain weight (TGW), and grain yield (GY). Breaking down the analysis by the main genotype-by-environment trends revealed QTLs and candidate genes specific to conditions like sowing date and latitude. A historical look on the evolution of QTL frequencies revealed that early selection focused on PH and TGW, likely due to their high heritability. GY selection occurred later, facilitated by reduced variance in other traits. The study observed that favourable alleles for plant height were often fixed before those for grain yield and TGW. Some regions showed linkage in repulsion, suggesting targets for future breeding. Several candidate genes were identified, including known genes and new candidates based on orthology with rice. Remarkably, the deficiens allele of gene Vrs1, appears associated to higher GY. These findings provide valuable insights for barley breeders aiming to improve yield, and other agronomic traits. HighlightA dense genome-wide meta-analysis provides new QTLs, reveals breeding history trends and identifies new candidate genes for yield, plant height, grain weight and heading time of spring barley.

genetics↗

bioRxiv2024

A single-cell atlas of spatial and temporal gene expression in the mouse cranial neural plate

The formation of the mammalian brain requires regionalization and morphogenesis of the cranial neural plate, which transforms from an epithelial sheet into a closed tube that provides the structural foundation for neural patterning and circuit formation. Sonic hedgehog (SHH) signaling is important for cranial neural plate patterning and closure, but the transcriptional changes that give rise to the spatially regulated cell fates and behaviors that build the cranial neural tube have not been systematically analyzed. Here we used single-cell RNA sequencing to generate an atlas of gene expression at six consecutive stages of cranial neural tube closure in the mouse embryo. Ordering transcriptional profiles relative to the major axes of gene expression predicted spatially regulated expression of 870 genes along the anterior-posterior and mediolateral axes of the cranial neural plate and reproduced known expression patterns with over 85% accuracy. Single-cell RNA sequencing of embryos with activated SHH signaling revealed distinct SHH-regulated transcriptional programs in the developing forebrain, midbrain, and hindbrain, suggesting a complex interplay between anterior-posterior and mediolateral patterning systems. These results define a spatiotemporally resolved map of gene expression during cranial neural tube closure and provide a resource for investigating the transcriptional events that drive early mammalian brain development.

developmental biology↗

bioRxiv2024

Newborn reactions to maternal prenatal stress alter umbilical cord blood tRNA fragments targeting cholinergic transcripts

Maternal perceived prenatal stress (PPS) is a known risk factor for diverse developmental impairments in newborns, but the underlying molecular processes are incompletely understood. Here, we report that maternal PPS altered the birth profiles of blood transfer RNA fragments (tRFs), 16-50nt long non-random cleavage products of tRNAs, in a sex-dependent manner. Importantly, comparing stressed versus control maternal and umbilical cord blood serum presented alterations that were not limited to individual tRFs, but rather reflected selective changes in particular tRF families grouped by their mitochondrial or nuclear genome origin, parental tRNA coded amino acid, and cleavage type. tRF families that show stress- and sex-specific effects, revealed shared length and expression patterns which were strongest in the female newborns. Several of these tRFs carry complementary motifs to specific cholinergic mRNAs, suggesting possible translational regulation similar to microRNAs. Compatible with the cholinergic regulation of stress reactions, those "CholinotRFs" achieved an AUC of 95% when classifying female newborns according to maternal PPS. Moreover, we found altered catalytic activity of serum acetylcholinesterase, which was particularly elevated in male newborns, marking a second sex-specific effect. Our findings demonstrate an association of tRF families patterns with newborns sex-specific stress response to PPS and may lead to better diagnosis and therapeutic tools for these and other stressors.

molecular biology↗

bioRxiv2024

Synovial fluid transcriptome dynamics in osteoarthritis progression: Implications in pathogenesis

BackgroundOsteoarthritis, a degenerative joint disease associated with various pathological manifestations in the joint including cartilage loss, alterations in subchondral bone and synovial inflammation. ObjectiveThis study aimed to elucidate the transcriptional and molecular changes in synovial fluid associated with OA progression, focusing on differential gene expression and pathway enrichment across OA grades. MethodologyPatients with different OA grades were recruited from PGIMER, Chandigarh, following the KL classification. Microarray analysis was conducted to study the transcriptional profiles in different OA grades using a fold-change (FC) cutoff of 2 and a p-value cutoff of 0.05, followed by pathway analysis performed using GSEA and STRING database. Selected genes from microarray and pathway analysis were validated using qRT-PCR. ResultsMicroarray analysis reveals distinct gene expression patterns corresponding to different OA stages (KL grade 2 to KL grade 4). Notably, the upregulation of AMTN and DKK2, alongside the downregulation of MSLN, highlighted their roles in pathological mineralization and disrupted bone remodeling in OA. Pathway enrichment analysis revealed significant changes in immune response, inflammation related pathways and cellular processes such as autophagy and programmed cell death, indicating their involvement in disease progression. Furthermore, mitochondrial dysfunction and impaired autophagy were linked to increased inflammation in advanced OA. ConclusionThese findings suggest that targeting mineralization and inflammatory pathways could offer novel therapeutic avenues for OA management.

pathology↗

bioRxiv2024

Neuronal DNA repair reveals strategies to influence CRISPR editing outcomes

Genome editing is poised to revolutionize treatment of genetic diseases, but poor understanding and control of DNA repair outcomes hinders its therapeutic potential. DNA repair is especially understudied in nondividing cells like neurons, which must withstand decades of DNA damage without replicating. This lack of knowledge limits the efficiency and precision of genome editing in clinically relevant cells. To address this, we used induced pluripotent stem cells (iPSCs) and iPSC-derived neurons to examine how postmitotic human neurons repair Cas9-induced DNA damage. We discovered that neurons can take weeks to fully resolve this damage, compared to just days in isogenic iPSCs. Furthermore, Cas9-treated neurons upregulated unexpected DNA repair genes, including factors canonically associated with replication. Manipulating this response with chemical or genetic perturbations allowed us to direct neuronal repair toward desired editing outcomes. By studying DNA repair in postmitotic human cells, we uncovered unforeseen challenges and opportunities for precise therapeutic editing.

molecular biology↗

bioRxiv2024

Digital pathology assessment of kidney glomerular filtration barrier ultrastructure in an animal model of podocytopathy

BackgroundTransmission electron microscopy (TEM) images can visualize kidney glomerular filtration barrier ultrastructure, including the glomerular basement membrane (GBM) and podocyte foot processes (PFP). Podocytopathy is associated with glomerular filtration barrier morphological changes observed experimentally and clinically by measuring GBM or PFP width. However, these measurements are currently performed manually. This limits research on podocytopathy disease mechanisms and therapeutics due to labor intensiveness and inter-operator variability. MethodsWe developed a deep learning-based digital pathology computational method to measure GBM and PFP width in TEM images from the kidneys of Integrin-Linked Kinase (ILK) podocyte-specific conditional knockout (cKO) mouse, an animal model of podocytopathy, compared to wild-type (WT) control mouse. We obtained TEM images from WT and ILK cKO littermate mice at 4 weeks old. Our automated method was composed of two stages: a U-Net model for GBM segmentation, followed by an image processing algorithm for GBM and PFP width measurement. We evaluated its performance with a 4-fold cross-validation study on WT and ILK cKO mouse kidney pairs. ResultsMean (95% confidence interval) GBM segmentation accuracy, calculated as Jaccard index, was 0.73 (0.70-0.76) for WT and 0.85 (0.83-0.87) for ILK cKO TEM images. Automated and manual GBM width measurements were similar for both WT (p=0.49) and ILK cKO (p=0.06) specimens. While automated and manual PFP width measurements were similar for WT (p=0.89), they differed for ILK cKO (p<0.05) specimens. WT and ILK cKO specimens were morphologically distinguishable by manual GBM (p<0.05) and PFP (p<0.05) width measurements. This phenotypic difference was reflected in the automated GBM (p<0.05) more than PFP (p=0.06) widths. ConclusionsThese results suggest that certain automated measurements enabled via deep learning-based digital pathology tools could distinguish healthy kidneys from those with podocytopathy. Our proposed method provides high-throughput, objective morphological analysis and could facilitate podocytopathy research and translate into clinical diagnosis. Key pointsO_LIWe leveraged U-Net architecture in an algorithm to measure the widths of glomerular basement membrane and podocyte foot processes. C_LIO_LIDeep learning-based automated measurement of glomerular filtration barrier morphology has promise in podocytopathy research and diagnosis. C_LI

pathology↗