Biology subjects

Kothapalli, C.

Publications and source records attributed to Kothapalli, C..

5 recordsLinked to original sources

bioRxiv2026

Coupled Transcriptomic and ECM-Mechanical Remodeling Reveal Mechanotransductive Pathways in Spinal Cord Injury

Spinal cord injury (SCI) leads to the formation of a chronic scar composed of glial and fibrotic components that severely restrict neural regeneration and functional recovery. While the scar composition has been widely studied, the spatiotemporal evolution of tissue mechanics and the role it plays in regulating the post-injury responses remain poorly understood. Here we present an integrated mechanobiological and multi-omics analysis of spinal cord remodeling following a severe thoracic contusion injury. Using nanoindentation and viscoelasticity measurements taken via atomic force microscopy (AFM), we demonstrate that SCI induces a dynamic mechanical response characterized by rapid tissue softening during the acute phase reaching a minimum at one-month post-injury, followed by progressive stiffening associated with chronic scar maturation at six months. Bulk RNA sequencing reveals that early mechanical softening coincides with strong activation of inflammatory and matrix-degrading pathways whereas chronic stiffening correlates with upregulation of collagen synthesis, extracellular matrix (ECM) organization and fibrotic remodeling pathways. Concurrently, mechanotransduction regulators exhibit temporally coordinated activation, indicating that cells dynamically sense and respond to evolving mechanical cues. Viscoelastic analysis further shows that chronic scar tissue exhibited increased stiffness and prolonged relaxation dynamics, reflecting dense collagen deposition and proteoglycan accumulation that reinforces a mechanically restrictive microenvironment. Together, these findings establish that the post-injury scar represents a dynamic mechanobiological system in which the evolving tissue mechanics, viscoelasticity and mechanotransduction collectively regulate ECM remodeling, resulting in regenerative failure. This study provides a comprehensive mechanobiological framework for SCI progression and highlights the opportunities for mechanically informed therapeutic strategies aimed at modulating scar mechanics to promote tissue repair. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/736147v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@543cc4org.highwire.dtl.DTLVardef@6185c6org.highwire.dtl.DTLVardef@95c3ceorg.highwire.dtl.DTLVardef@6a12ea_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

Mechanostimulatory cues determine intestinal fibroblast fate and profibrotic remodeling in a physiodynamic human gut-on-a-chip

Biomechanical cues, including shear stress and mechanical strain, are key regulators of intestinal cellular behavior, yet their mechanostimulatory impact on fibroblasts responses during early fibrotic remodeling remains poorly understood. Using a bioengineered gut-on-a-chip model, we independently modulated flow and mechanical strain to assess fibroblast dynamics under intact or impaired epithelial barriers. Inflammation-associated fibroblasts resisted biomechanical stress, exhibiting myofibroblast-like phenotypes with hypertrophy and elevated -smooth muscle actin aligned with stress fibers. In contrast, normal fibroblasts were highly susceptible to shear stress, undergoing matrix metalloproteinase-dependent apoptotic injury, while mechanical strain alone had minimal effect. Notably, an intact epithelial barrier was both necessary and sufficient to protect fibroblasts from shear-induced damage, suggesting that "good fences make good neighbors". Under barrier dysfunction, prolonged exposure to shear stress induced the formation of stiff fibroblast aggregates composed of mechanoadaptive myofibroblast-like cells. These findings identify mechanostimulatory cues, particularly shear stress, as critical drivers of early fibrotic remodeling in inflammatory bowel disease and underscore epithelial barrier integrity as an essential biomechanical safeguard against pathological fibroblast dysregulation.

bioengineering↗

bioRxiv2024

Spatial characterizations of bacterial dynamics for food safety: Modeling for shared water processing environments

Bacterial dynamics occurring in shared water environments during food processing are typically modeled assuming a homogeneous mixing profile. However, given the tank configurations, and water recirculation and reuse specifications used in many facilities, uniform mixing is not always applicable. Towards this goal, we here developed a novel reaction-diffusion-advection model that captures temporal and spatial variations in the water tanks under dynamic conditions. We utilize the dynamics involved in poultry chilling as an example, as this process features a comprehensive interplay of bacteria, water chemistry and water flow dynamics, as well as determining bacteria levels on carcasses moving into final phases of the food production chain, thus directly influencing public health risk. Well-posedness, existence and uniqueness of positive steady-state solutions with global stability are proved, as well as an estimation of the time scale of convergence to the steady-state solution provided. Simulations are used to verify the analytical results incorporating parameters informed by experimental data from generic, non-pathogenic E. coli, and predictively estimate the time to equilibrium. We show that during a typical 8 h processing shift, the model reaches steady state within 2 h, applying this result to validate model simulations against commercial data. The calibrated model predicts a distribution of E. coli levels on post-chill carcasses with mean and standard deviation of 3.35 {+/-} 0.56 Log10 CFU/carcass, which closely compares to the experimentally observed distribution of 3.55 {+/-} 0.64 Log10 CFU/carcass in an industrial setting. Our results reinforce the key role of space in quantifying essential mechanisms that govern water chemistry and E. coli dynamics during poultry chilling. Our model is an important tool to improve decision making for pathogen control during poultry chilling, as well as a blueprint from which models for processing other commodities like fresh produce and pork can be established.

microbiology↗

bioRxiv2024

Integrative Analysis of Gene Expression, Protein Abundance, and Metabolomic Profiling Elucidates Complex Relationships in Chronic Hyperglycemia-Induced Changes in Human Aortic Smooth Muscle Cells

Type 2 diabetes mellitus (T2DM) is a major public health concern with significant cardiovascular complications (CVD). Despite extensive epidemiological data, the molecular mechanisms relating hyperglycemia to CVD remain incompletely understood. We here investigated the impact of chronic hyperglycemia on human aortic smooth muscle cells (HASMCs) cultured under varying glucose conditions in vitro, mimicking normal (5 mmol/L), pre-diabetic (10 mmol/L), and diabetic (20 mmol/L) conditions, respectively. Patient-derived T2DM-SMCs served as disease phenotype controls. Results showed significant increases in cellular proliferation, area, perimeter, and F-actin expression with increasing glucose concentration (p < 0.01), albeit not exceeding the levels in T2DM cells. Atomic force microscopy analysis revealed significant decreases in Youngs moduli, membrane tether forces, membrane tension, and surface adhesion in SMCs at higher glucose levels (p < 0.001), with T2DM-SMCs being the lowest among all the cases (p < 0.001). T2DM-SMCs exhibited elevated levels of pro-inflammatory markers such as IL-6, IL-8, and MCP-1 compared to glucose-treated SMCs (p < 0.01). Conversely, growth factors such as FGF-2 and TGF-{beta} were higher in SMCs exposed to 10 mmol/L glucose but lower in T2DM-SMCs (p < 0.01). Pathway enrichment analysis showed significant increases in the expression of inflammatory cytokine-associated pathways, especially involving IL-10, IL-4 and IL-13 signaling in genes that are up-regulated by elevated glucose levels. Differentially regulated gene (DGE) analysis showed that compared to normal glucose receiving SMCs, 513 genes were upregulated and 590 genes were downregulated in T2DM-SMCs; fewer genes were differentially expressed in SMCs receiving higher glucose levels. Finally, the altered levels in genes involved in ECM organization, elastic fiber synthesis and formation, laminin interactions, and ECM proteoglycans were identified, which highlight the role of hyperglycemia in vascular remodeling and CVD progression. Our results collectively suggest that chronic hyperglycemia in vascular SMCs leads to morphological, biomechanical, and functional alterations, potentially contributing to the pathogenesis of T2DM-associated CVD. The observed differences in gene expression patterns between in vitro hyperglycemic models and patient-derived T2DM-SMCs highlight the complexity of T2DM pathophysiology and underline the need for further studies.

bioengineering↗

bioRxiv2021

Chlorine inactivation of Escherichia coli O157:H7 in fresh produce wash process: effectiveness and modeling

This study presents a modified disinfection kinetics model to evaluate the potential effect of organic content on the chlorine inactivation coefficient of Escherichia coli O157:H7 in fresh produce wash processes. Results show a significant decrease in the bactericidal efficacy of free chlorine (FC) in the presence of organic load compared to its absence. While the chlorine inactivation coefficient of Escherichia coli O157:H7 is 70.39 {+/-} 3.19 L.mg-1.min-1 in the absence of organic content, it drops by 73% in chemical oxygen demand (COD) level of 600 - 800 mg.L-1. Results also indicate that the initial chlorine concentration and bacterial load have no effect on the chlorine inactivation coefficient. A second-order chemical reaction model for FC decay, which utilizes a percentage of COD as an indicator of organic content in fresh produce wash was employed, yielding an apparent reaction rate of (9.45 {+/-} 0.22) x 10-4 M-1.min-1. This model was validated by predicting FC concentration (R2 = 0.96) in multi-run continuous wash cycles with periodic replenishment of chlorine.

microbiology↗