Biology subjects

Sharma, P. K.

Publications and source records attributed to Sharma, P. K..

12 recordsLinked to original sources

bioRxiv2026

Long-Term Human Skin Platform for Modeling Chronic Inflammation, Environmental Stress, and Therapeutic Intervention

Chronic inflammation drives tissue dysfunction and aging, yet the dynamic interplay between persistent inflammatory signaling and structural deterioration remains difficult to study in human-relevant systems. Here, an advanced long-term human skin platform is presented that preserves native tissue architecture and epidermal, stromal, and immune-associated molecular programs for up to 4 weeks. Using this system, sustained cytokine-driven inflammation was modeled, demonstrating chronic inflammatory transcriptional programs, progressive histopathological changes, and persistent inflammatory mediator secretion that were broadly suppressed by the JAK inhibitor tofacitinib. Using aged donor tissue, prolonged senolytic-associated treatment attenuated inflammatory and remodeling pathways. Finally, UVB exposure triggered coordinated stress and inflammatory responses that were partially mitigated using topical sunscreen, demonstrating compatibility with environmental stress modeling and topical intervention within preserved tissue architecture. Together, these findings establish a versatile human skin platform for modeling chronic inflammation, aging-associated tissue remodeling, and environmental stress, providing a translational framework for investigating skin tissue dysfunction and evaluating therapeutic interventions.

bioengineering↗

bioRxiv2026

Gut microbiota-derived indole-3 acetic acid mitigates key hallmarks of metabolic dysfunction-associated steatotic liver disease (MASLD) in an NLRP3-dependent manner in in vitro and diet-induced mouse models

BackgroundMetabolic-dysfunction associated steatotic liver disease(MASLD) is a global epidemic affecting >30 % global population with no approved therapies till date. Recent reports suggest that activation of NLRP3 inflammasome may be involved in the pathogenesis of MASLD. We, therefore, aimed to identify small molecule inhibitor(s) of NLRP3 inflammasome as a potential therapeutic strategy to manage MASLD and validate their efficacy using in vitro and in vivo models of MASLD. MethodologyWe screened an in-house library of natural products using an in vitro phenotypic assay and identified a gut microbiota derived metabolite of dietary Tryptophan; indole-3 acetic acid (I3A) for its ability to inhibit the levels of IL-1{beta} and IL-18, which are elevated as a result of activation of NLRP3 inflammasome in differentiated THP1 cells. Subsequently, we carried out several in vitro and in vivo studies to confirm the mechanism of action of I3A and its ability to mitigate the key hallmarks of MASLD ResultsOur in vitro data suggest that I3A is an inhibitor of NLRP3 inflammasome. I3A was also found to improve the blood glucose level, plasma lipid profile, hepatic fat, and liver function in high-fat-high-fructose diet induced model of MASLD using C57BL/6 mice. ConclusionOur results show that I3A, which has been previously reported to be a gut microbiota-derived metabolite of dietary tryptophan, mitigates the key hallmarks of MASLD in an NLRP3 dependent manner. A dedicated structure-activity-relationship (SAR) study around the I3A chemotype may be carried out in future to identify novel NLRP3 inhibitors with desirable pharmacological profile.

pharmacology and toxicology↗

bioRxiv2026

Importance of tribo-pairs to mimic blinking in vitro for dry eye disease research

Selecting suitable tribo-pairs is crucial for measuring the tribological properties of the blinking process, especially for dry eye disease research. The tribo-pairs, lubricants, loads, and sliding speeds used in the friction models reported so far vary greatly, which limits the development of artificial tear fomulations, that could be effective in treating the effects of dry eye disease. This study compares tribo-pairs under the same experimental conditions and provides a test model closer to the real physiological blinking environment. This study proposes a to use the porcine eyeball-eyelid tribo-pair as an ex vitro tissue friction model to explore the tribological behavior during blinking. Additionally, the presence of mucin on the eyelids and cornea was detected. The tribo-pair was compared with the eyeball-glass and eyeball-mucin coated glass tribo-pairs in terms of friction coefficient, relief time, and wear. Artificial tribo-pairs such as contact lens-glass or contact lens-mucin coated glass were not included because of their irrelevance to dry eye disease. The results showed that the static friction coefficient of the eyelid/eyeball tribo-pairs was significantly lower than that of the bare glass/eyeball group. In addition, its dynamic friction coefficient was higher than that of the glass/eyeball tribo-pairs, but the friction damage caused was lower than that of the glass/eyeball group. The relief period (RP) of the eyelid/eyeball tribo-pair was significantly higher than that of bare glass and mucin-coated glass, showing stronger hydrophilicity within this system. To conduct relevant dry eye disease (DED) research, it is critical to simulate the natural eyelid-eyeball friction system as realistically as possible. Despite its limitations, the use of the porcine eye as an in vitro model provides a structurally and biomechanically realistic platform to capture the key interactions between the eyelid and the ocular surface. This approach allows for a more accurate assessment of friction, tear film dynamics, and therapeutic interventions in dry eye.

bioengineering↗

bioRxiv2025

Fibroblast alignment is governed by stiffness interfaces in hydrogels.

Transitions in mechanical properties between different tissue scaffolds, such as extracellular matrices (ECMs), are common in the human body and influence cellular orientation. For example, in teeth, the abrupt transition between soft ([~]5 kPa) dental pulp and stiff (>100 kPa) dentin directs the alignment of odontoblasts. In this study, hydrogels, with defined mechanical transitions were used to evaluate the phenotypic response of fibroblasts to either a soft/soft (3 kPa/3 kPa) or soft/stiff (3 kPa/200 kPa) interface. Near the soft/soft interface fibroblasts aligned in a more parallel fashion to the interface (11{degrees} angle to the interface), compared to the more perpendicular fashion (69{degrees} angle to the interface) observed at the soft-stiff interface. Notably, regions of alignment also showed an increased proportion of alpha smooth muscle actin (SMA)-positive cells, indicating myofibroblast differentiation in response to the mechanical transition. These findings demonstrate that modifying a biomaterial by introducing an interface alters the bioactivity of responding cells solely through mechanical mechanisms, without any change to the cells biochemical environment. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=147 HEIGHT=200 SRC="FIGDIR/small/695439v1_ufig1.gif" ALT="Figure 1000"> View larger version (42K): org.highwire.dtl.DTLVardef@d0ca04org.highwire.dtl.DTLVardef@17ee49forg.highwire.dtl.DTLVardef@1d389a5org.highwire.dtl.DTLVardef@f1b2a0_HPS_FORMAT_FIGEXP M_FIG C_FIG Schematic summary showing interface-induced fibroblast orientation and variety in phenotypic expression. On the bottom left the perpendicular orientation of fibroblast (skin tone) and myofibroblast (pink) on a soft/soft (3kPa/3kPa) GelMA hydrogel interface and on the right side the parallel orientation near a soft/stiff (3kPa/200kPa) GelMA hydrogel interface with greater collagen deposition, depicted by purple halos.

bioengineering↗

bioRxiv2025

Contextual Science and Genome Analysis for Air-Gapped AI Research

Provided here is a study of large language models (LLMs) and retrieval augmented generation (RAG) frameworks in air-gapped environments for genome research on small grain crops. We developed two main applications: (1) a RAG-based system for contextual analysis of scientific literature, collecting over 5,000 PDFs on wheat pathogens, and (2) a GFF3 file analysis tool called Genoma that enables exploration of genome annotation through an interactive interface. Using the open-source framework Ollama, we compared the performance of multiple LLMs including Llama3.1, Deepseek-r1, and Qwen2.5 for biological data analysis. A LightRAG approach provided semantic visualization of document relationships, while the Genoma tool offered chromosome-level insights into genome annotations. These tools demonstrate the viability of powerful AI assistance for sensitive research environments, with potential applications for pangenome analysis and gene discovery. The code provides researchers with practical solutions for implementing AI in secure settings without sacrificing analytical power.

bioinformatics↗

bioRxiv2025

Contrasting responses of control and fibrotic lung fibroblasts to fibrotic stimuli: the role of osteoprotegerin in extracellular matrix remodeling

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by dysregulated wound healing, leading to excessive production of extracellular matrix (ECM) proteins, particularly collagen, by activated fibroblasts. Osteoprotegerin (OPG), a soluble protein associated with ECM remodeling in bone, has been found in higher levels in serum and lung tissue of IPF patients compared to controls. However, whether OPG is associated with ECM remodeling by fibroblasts in lung fibrosis remains poorly understood. In this study we assessed differences in OPG levels in ECM-derived hydrogels from non-disease controls and patients with IPF encapsulated with primary human lung fibroblasts from control and patients with IPF (7 days). OPG levels were assessed in a collected culture medium and stained lung tissue sections, and related to biomechanical properties. Fibrotic human lung fibroblasts secreted and deposited more OPG compared to controls, which was observed in both non-diseased and IPF ECM hydrogels. OPG levels correlated significantly with matrix stiffness and collagen fiber structural properties, but only in IPF hydrogels, independent of fibroblast source. Strikingly, we also observed opposite correlations for control and fibrotic fibroblasts in fibrotic hydrogels. Control fibroblasts within a fibrotic microenvironment, secreted less OPG when hydrogel stiffness increased and deposited more OPG when collagen fibers were more aligned. Interestingly, fibrotic fibroblasts secreted more OPG when collagen fiber length increased and when collagen fiber curvature increased. Overall, our findings suggest that control and fibrotic lung fibroblasts exhibited opposite behavior with respect to OPG and ECM remodeling under fibrotic conditions and this may have consequences for matrix stiffness

cell biology↗

bioRxiv2025

TaWUS2D regulates the number of grains per spikelet by enhancing the number of fertile ovaries in Multi-Ovary Wheat

Innovative genetic improvements in the staple crop Triticum aestivum (bread wheat) are urgently needed to address the growing global food security crisis. Here, we report the map-based cloning of TaWUS2D, the gene responsible for the dominant multi-ovary phenotype in wheat. Multi-ovary lines are characterized by the development of three fertile ovaries per floret that results in three grains, as opposed to wildtype single ovary wheat. We used HiFi long-reads to assemble a 14.48 Gbp genome scaffold assembly in the background of mutli-ovary wheat line MOV. Using high-resolution genetic mapping, combined with additional genomic resources, we defined the Mov-1 locus to a 135 Kbp region containing two genes. Using five independent deletion mutants and eight TILLING mutants, we demonstrate that a functional WUSCHEL-like protein, TaWUS2D, is required for the multi-ovary phenotype. TaWUS2D is upregulated in the MOV genetic background. This research lays the groundwork for developing new approaches to improve wheat production potential and sustainability in the face of current and future global food challenges.

plant biology↗

bioRxiv2023

Unravelling Silicon's Transcriptomic Armor in Soybean against Macrophomina phaseolina causing Charcoal Rot Disease

The Glycine max L. has been affected by more than 100 diseases, including Macrophomina phaseolina producing charcoal rot disease, which reduces production by 70%. In this investigation, RNA-Seq analysis is used for the first time to explore role of silicon in preventing soybean charcoal rot. The study explores the molecular mechanism underlying soybeans resilience to charcoal rot when treated with potassium silicon. It was meticulously investigated how Macrophomina phaseolina entered the roots. The SEM, which showed a strong link between potassium silicate accumulation and disease resistance. Further investigation indicates that a potassium silicate concentration of 1.7mM lowers disease incidence. Using Illumina HiSeq NGS data, we present a transcriptome analysis revealing genes associated with charcoal rot resistance, highlighting 3,106 genes with distinct expression patterns. The strong enrichment of pathways including "Biosynthesis of ansamycins" and "Flavone and flavonol biosynthesis," which contribute to resistance against charcoal rot, is highlighted by KEGG enrichment analysis. The ERF transcription factor and NB leucine-rich repeats stands out among the differentially expressed genes as being particularly connected to resistance. The crucial functions that many other important transcription factors, including as MYB, NAC, and proteins from the FAR1 family, play in enhancing soybeans resistance to charcoal rot are also noted. This newly discovered information could help in developing tactics to strengthen soybeans resistance to Macrophomina phaseolina.

microbiology↗

bioRxiv2023

Single-cell immune multi-omics and repertoire analyses in pancreatic ductal adenocarcinoma reveal differential immunosuppressive mechanisms within different tumour microenvironments

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis. Understanding the multiple mechanisms by which the tumour evades immune control, and how these mechanisms may be disrupted is critical to developing targeted immunotherapies. Previous studies have shown that higher lymphocyte infiltration is associated with better survival, and here we investigated what mediates these differences. We performed a comprehensive analysis of PDAC-associated immune cells using single cell multi-omics coupled with re-analysis of public PDAC scRNA-seq datasets. We introduce novel single-cell and repertoire analyses that have uncoupled diverse roles and contributions of various immune cell populations within different tumour microenvironments (TMEs). They revealed clear distinctions in the clonal characteristics among different patient groups, provided valuable insights into the mechanisms of immune cell migration and tissue adaptation underlying these disparities. These results point to differential CD4 polarisation of intra-tumoural T cells, differential B cell differentiation, GC reactions, antigen presentation pathways, and distinct cell-cell communication between the myeloid-enriched and adaptive-enriched groups. Overall, we identified two major distinct themes for future immune intervention within PDAC patients between those with higher adaptive versus myeloid immune cell infiltration.

immunology↗

bioRxiv2022

An in vitro model of fibrosis using crosslinked native extracellular matrix-derived hydrogels to modulate biomechanics without changing composition

Extracellular matrix (ECM) is a dynamic network of proteins, proteoglycans and glycosaminoglycans, providing structure to the tissue and biochemical and biomechanical instructions to the resident cells. In fibrosis, the composition and the organization of the ECM are altered, and these changes influence cellular behaviour. Biochemical (i. e. protein composition) and biomechanical changes in ECM take place simultaneously in vivo. Investigating these changes individually in vitro to examine their (patho)physiological effects has been difficult. In this study, we generated an in vitro model to reflect the altered mechanics of a fibrotic microenvironment through applying fibre crosslinking via ruthenium/sodium persulfate crosslinking on native lung ECM-derived hydrogels. Crosslinking of the hydrogels without changing the biochemical composition of the ECM resulted in increased stiffness and decreased viscoelastic stress relaxation. The altered stress relaxation behaviour was explained using a generalized Maxwell model. Fibre analysis of the hydrogels showed that crosslinked hydrogels had a higher percentage of matrix with a high density and a shorter average fibre length. Fibroblasts seeded on ruthenium-crosslinked lung ECM-derived hydrogels showed myofibroblastic differentiation with a loss of spindle-like morphology together with greater -smooth muscle actin (-SMA) expression, increased nuclear area and circularity without any decrease in the viability, compared with the fibroblasts seeded on the native lung-derived ECM hydrogels. In summary, ruthenium crosslinking of native ECM-derived hydrogels provides an exciting opportunity to alter the biomechanical properties of the ECM-derived hydrogels while maintaining the protein composition of the ECM to study the influence of mechanics during fibrotic lung diseases.

pathology↗

bioRxiv2021

Computational and biochemical analyses reveal that cofilin-2 self assembles into amyloid-like structures and promotes the aggregation of other proteinaceous species: Pathogenic relevance to myopathies

Cofilin-2 is a member of the ADF/cofilin family, expressed extensively in adult muscle cells and involved in muscle maintenance and regeneration. Phosphorylated cofilin-2 is found in pre-fibrillar aggregates formed during idiopathic dilated cardiomyopathy. A recent study shows that phosphorylated cofilin-2, under oxidative distress, forms fibrillar aggregates. However, it remains unknown if cofilin-2 holds an innate propensity to form amyloid-like structures. In the present study, we employed various computational and biochemical techniques to explore the amyloid-forming potential of cofilin-2. We report that cofilin-2 possesses aggregation-prone regions (APRs), and these APRs get exposed to the surface, become solvent-accessible, and are involved in the intermolecular interactions during dimerization, an early stage of aggregation. Furthermore, the cofilin-2 amyloids, formed under physiological conditions, are capable of cross-seeding other monomeric globular proteins and amino acids, thus promoting their aggregation. We further show that Cys-39 and Cys-80 are critical in maintaining the thermodynamic stability of cofilin-2. The destabilizing effect of oxidation at Cys-39 but not that at Cys-80 is mitigated by Ser-3 phosphorylation. Cysteine oxidation leads to partial unfolding and loss of structure, suggesting that cysteine oxidation further induces early events of cofilin-2 aggregation. Overall, our results pose a possibility that cofilin-2 amyloidogenesis might be involved in the pathophysiology of diseases, such as myopathies. We propose that the exposure of APRs to the surface could provide mechanistic insight into the higher-order aggregation and amyloidogenesis of cofilin-2. Moreover, the cross-seeding activity of cofilin-2 amyloids hints towards its involvement in the hetero-aggregation in various amyloid-linked diseases.

biochemistry↗

bioRxiv2021

MM-Deacon: Multimodal molecular domain embedding analysis via contrastive learning

AO_SCPLOWBSTRACTC_SCPLOWMolecular representation learning plays an essential role in cheminformatics. Recently, language model-based approaches have been popular as an alternative to traditional expert-designed features to encode molecules. However, these approaches only utilize a single modality for representing molecules. Driven by the fact that a given molecule can be described through different modalities such as Simplified Molecular Line Entry System (SMILES), The International Union of Pure and Applied Chemistry (IUPAC), and The IUPAC International Chemical Identifier (InChI), we propose a multimodal molecular embedding generation approach called MM-Deacon (multimodal molecular domain embedding analysis via contrastive learning). MM-Deacon is trained using SMILES and IUPAC molecule representations as two different modalities. First, SMILES and IUPAC strings are encoded by using two different transformer-based language models independently, then the contrastive loss is utilized to bring these encoded representations from different modalities closer to each other if they belong to the same molecule, and to push embeddings farther from each other if they belong to different molecules. We evaluate the robustness of our molecule embeddings on molecule clustering, cross-modal molecule search, drug similarity assessment and drug-drug interaction tasks.

bioinformatics↗