Increase In Cell Size Research Articles

The STRIPAK associated kinase MST4 is a novel mediator in heart failure pathogenesis

Abstract Heart failure still poses substantial challenges in understanding its underlying molecular pathways. We recently found the mammalian STE20-like kinase 4 (MST4) significantly upregulated in human failing hearts (5.7-fold in DCM and 3.8-fold ICM) as well as in heart failure animal models (i.e. 2.5-fold in Calsarcin-1-KO, 2.5-fold in MLP-KO). MST4 is a member of striatin interacting phosphatases and kinases complexes (STRIPAK), an emerging group of multiprotein complexes responsible for integrating cellular signalling pathways. We provide the first evidence of functional STRIPAK complexes containing MST4 by co-immunoprecipitation and interactomics experiments in cardiomyocytes. Moreover, we found MST4 to interact with several intercalated disc proteins like beta-Catenin or Desmin. Adenoviral overexpression of MST4 in neonatal rat ventricular cardiomyocytes (NRVCM) results in a significant increase in cell size (+13%). This was not accompanied by the activation of fetal genes such as NPPA, NPPB or RCAN1.4, but rather by an increase in phosphorylation of Protein kinase B (PKB/Akt, 3.3-fold). Akt is usually associated with physiological hypertrophy, indicating that MST4 may be involved in protective pathways in cardiomyocytes. In support of this notion, MST4 overexpression reduced apoptotic activity (cleavage of Caspase 3 -69%, Caspase 7 -80%, Parp1 -27%) and improved both contractility (fractional shortening cell +23%, fractional shortening sarcomere +30%, time to max. contraction cell -10%, time to max. contraction sarcomere -12%) and relaxation parameters (time to max. relaxation velocity cell -12%) in isolated adult rat ventricular cardiomyocytes. In order to identify cardiac targets of MST4, we performed a comprehensive analysis of the phosphoproteome of NRVCM overexpressing MST4 compared with control-virus +/- pharmacological inhibitor at two time points. We identified more than 70,000 peptides including more than 20,000 phosphopeptides in more than 4,000 protein groups. Using linear modelling with a reduced data set containing regulated features selected by thresholds for p-value and fold change, we observed a consistent MST4 effect and a number of enriched gene ontology terms. Here, we found several potential MST4 targets and effects on protein expression levels associated with intercalated disc proteins. In human heart samples, MST4 was also localized to the intercalated disc region by immunostaining. Interesting proteins in that context that might help explain some of the observed cardioprotective MST4 effects are Connexin 43, Desmin, Ryanodine receptor, Phospholemman, Junctophilin2, Myozap or Frizzled 1. Taken together, our data imply that MST4 upregulation in human heart failure serves an adaptive role which may offer translational opportunities.Graphical Abstract

Study on foaming behavior of block copolymer/inorganic particles co‐construction of toughened epoxy resin foams

AbstractLow toughness and brittleness limit its application range of thermosetting epoxy resin (EP) based foams. In current research, inorganic particles are commonly utilized as heterogeneous nucleating agents to enhance foaming quality and EP toughness. However, the increasing inorganic particle content usually leads to particle agglomeration, which negatively impacts foaming quality and reduces EP performance. Block copolymers, which appear as liquid to effectively mitigate agglomeration, are employed as toughening materials for EP. In this study, a small number of modified calcium silicate particles (MCS) were used as anchor points to induce the distribution of block copolymers (P‐F68) to improve EP toughness and effectively enhance cell nucleation, thus, EP/MCS/P‐F68 foams performance was improved. The research results showed that EP foams obtained excellent cell structure and very small foam density (0.256 g/cm3) at the P‐F68 content of 10 wt%. The continuous increase of P‐F68 content would lead to the thickening of cell wall and the increase of cell size. Simultaneously, the core‐shell structure formed by P‐F68 in EP effectively enhanced the toughness of EP foams and mitigated its brittleness, offering crucial theoretical guidance for toughening and regulating the cell structure of EP foams.

Corneal Endothelial Changes in Chinese Patients with Fuchs’ Uveitis Syndrome

ABSTRACT Purpose To analyze the changes of corneal endothelial cells in Chinese patients with unilateral Fuchs’ uveitis syndrome (FUS) and investigate the factors relevant to these changes. Methods Bilateral specular microscopic examination was performed in 459 Chinese patients with unilateral FUS from April 2008 to April 2023. The affected eyes constituted the study group, while the contralateral eyes served as controls. Results The median values of endothelial cell density (ECD), cell count, total cell size, and hexagonality were significantly lower in the FUS eyes compared to the control eyes (p < 0.001). The median values of average cell size, maximum cell size, SD of cell size, and CV were significantly higher in the FUS eyes compared to the control eyes (p < 0.001). Central ECD showed a negative correlation with age (r = −0.339; p < 0.001), maximum IOP (r = −0.127; p = 0.006), and the interval since symptom onset (r = −0.172; p < 0.001). The ECD was lower in eyes with ocular hypertension compared to those without ocular hypertension (p < 0.001). Eyes with KPs distributed on the central corneal endothelium had a significantly lower ECD than those with KPs distributed diffusely or KPs distributed triangularly on the inferior corneal endothelium (p = 0.006). Conclusion Our findings suggest decreased ECD, increased cell size, and morphological alterations in the affected eyes of Chinese patients with FUS. The reduction in ECD is correlated with age, elevated IOP, the interval since symptom onset, and the distribution of KPs.

Experimental and analytical study on the compressive behavior of PMI foam with different densities and cell sizes under intermediate strain rates

Polymethacrylimide (PMI) foam materials have great potential for applications in the field of protective energy absorption owing to their superior compressive properties. Existing studies on the mechanical behavior of PMI foams are limited, particularly for loading at intermediate strain rates. This paper presents a comprehensive experimental study of PMI foam with four different densities under quasi-static and intermediate strain rate compression (0.001 s−1 to 100 s−1). Each density included three different cell sizes to determine their effects on the compressive performance. Loads parallel and perpendicular to the foam rise direction were considered to investigate the anisotropic behavior. Intermediate strain rate tests were conducted using a high-speed hydraulic servo testing machine, which achieved a stable strain rate while ensuring consistent specimen sizes in both quasi-static and dynamic tests. In all the experiments, the compression process was captured using a high-speed camera and the macroscopic deformation mode and microscopic deformation mechanism were analyzed by combining Digital Image Correlation (DIC) and Scanning Electron Microscopy (SEM). The PMI foam with finer cell sizes exhibited an enhanced compression performance. As the strain rate increased, the strain rate effect became more evident in the high-density specimens and an increase in cell size diminished this effect. A modified analytical model incorporating the cell-size correction term was developed based on Gibson and Ashby's model. The modified model exhibited an average error of 4.9 % in the predicted plateau stress of PMI foam with different cell sizes at the same density.

Ethanolic extract of Parkia speciosa pods exhibits antioxidant and anti-inflammatory properties in lipopolysaccharide-induced murine macrophages by inhibiting the p38 MAPK pathway

BackgroundParkia speciosa (PS) is commonly used in Southeast Asian cuisine and traditional medicine to treat diabetes, hypertension, dermatitis, and kidney diseases. PS has emerged as a subject of interest because of its potential antioxidation and anti-inflammatory properties. However, despite its historically long and wide usage, a comprehensive investigation of these properties in PS pods (PSp) have not been conducted. Aims of this studyThis study aimed to identify the phytochemical compounds in the ethanolic extract of PSp collected from Southern Thailand and assess whether PSp exhibit antioxidant properties and mitigate inflammation in a lipopolysaccharide (LPS)-induced RAW264.7 model. Materials and methodsThe ethanolic extract of PSp was comprehensively analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC/MS) to identify its phytochemical constituents. To assess the antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) assays were performed, and cytotoxicity was evaluated using the MTT assay. The effect of PSp on reactive nitrogen and oxygen species (RNS and ROS) was determined using a nitric oxide (NO) assay, and its effect on pro-inflammatory cytokines was assessed using enzyme-linked immunosorbent assay (ELISA) and real-time quatitvative polymerase chain reaction (qPCR). Morphological changes following treatment were observed using a microscope. Western blot analysis was performed to quantify MAPK pathway expression. ResultsPSp contain polyphenols, phytosterols, triterpenes, oxaloacetic acid, and unsaturated fatty acids. PSp demonstrated high antioxidant potential in scavenging free radicals and exhibited no cytotoxic effects on macrophages. Moreover, PSp effectively reduced NO release and inhibited pro-inflammatory cytokines such as IL1-β, TNF-α, and IL-6. PSp treatment induced notable morphological changes in macrophages, characterized by an increase in cell size and the presence of intracellular vacuoles. In addition, Western blot analysis showed the selective suppressive effect of PSp on the p38-MAPK pathway. ConclusionPSp possess strong antioxidant and anti-inflammatory properties, making it a potential therapeutic agent for the treatment of inflammatory disorders.

Meflin/ISLR is a marker of adipose stem and progenitor cells in mice and humans that suppresses white adipose tissue remodeling and fibrosis.

Identifying specific markers of adipose stem and progenitor cells (ASPCs) in vivo is crucial for understanding the biology of white adipose tissues (WAT). PDGFRα-positive perivascular stromal cells represent the best candidates for ASPCs. This cell lineage differentiates into myofibroblasts that contribute to the impairment of WAT function. However, ASPC marker protein(s) that are functionally crucial for maintaining WAT homeostasis are unknown. We previously identified Meflin as a marker of mesenchymal stem cells (MSCs) in bone marrow and tissue-resident perivascular fibroblasts in various tissues. We also demonstrated that Meflin maintains the undifferentiated status of MSCs/fibroblasts. Here, we show that Meflin is expressed in WAT ASPCs. A lineage-tracing experiment showed that Meflin+ ASPCs proliferate in the WAT of obese mice induced by a high-fat diet (HFD), while some of them differentiate into myofibroblasts or mature adipocytes. Meflin knockout mice fed an HFD exhibited a significant fibrotic response as well as increases in adipocyte cell size and the number of crown-like structures in WAT, accompanied by impaired glucose tolerance. These data suggested that Meflin expressed by ASPCs may have a role in reducing disease progression associated with WAT dysfunction.

Effect of Cell Size on the Mechanical Properties of the Porous Structure of a CuCrZr Alloy Formed by Selective Laser Melting Technology

The porous structure has been widely used in heat sinks in aerospace fields because of its good specific strengthand lightweight. The porous structure formed by selective laser melting technology offers many advantages, but it also presents some challenges, for instance, how to how to ensure that the density is greatly reduced without sacrificing the material's mechanical properties. The Schoen I‐graph‐wrapped package structure with different cell sizes under the same volume fraction had been designed and fabricated by selective laser melting technology using CuCrZr powder as the raw material. The microstructure, grain orientation, and static properties were explored. At the same volume fraction, the pores were almost completely blocked when the cell size was 2 mm, with reduced powder adhesion when the cell size was 9 mm. As the cell size decreases, the compressive strength increases, with the compressive strength reaching 180 MPa at a cell size of 2 mm. Moreover, the energy absorption efficiency increases with the increase in cell size, with the highest energy absorption efficiency of 28% at a cell size of 9 mm. The limit dimensions under these conditions were determined to provide a reference for related research in this field.

Characterization of Photo-Crosslinked Methacrylated Type I Collagen as a Platform to Investigate the Lymphatic Endothelial Cell Response

Despite chronic fibrosis occurring in many pathological conditions, few in vitro studies examine how fibrosis impacts lymphatic endothelial cell (LEC) behavior. This study examined stiffening profiles of PhotoCol®—commercially available methacrylated type I collagen—photo-crosslinked with the photoinitiators: Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), Irgacure 2959 (IRG), and Ruthenium/Sodium Persulfate (Ru/SPS) prior to evaluating PhotoCol® permeability and LEC response to PhotoCol® at stiffnesses representing normal and fibrotic tissues. Ru/SPS produced the highest stiffness (~6 kilopascal (kPa)) for photo-crosslinked PhotoCol®, but stiffness did not change with burst light exposures (30 and 90 s). The collagen fibril area fraction increased, and dextran permeability (40 kilodalton (kDa)) decreased with photo-crosslinking, showing the impact of photo-crosslinking on microstructure and molecular transport. Human dermal LECs on softer, uncrosslinked PhotoCol® (~0.5 kPa) appeared smaller with less prominent vascular endothelial (VE)-cadherin (cell–cell junction) expression compared to LECs on stiffer PhotoCol® (~6 kPa), which had increased cell size, border irregularity, and VE-cadherin thickness (junction zippering) that is consistent with LEC morphology in fibrotic tissues. Our quantitative morphological analysis demonstrates our ability to produce LECs with a fibrotic phenotype, and the overall study shows that PhotoCol® with Ru/SPS provides the necessary physical properties to systematically study LEC responses related to capillary growth and function under fibrotic conditions.

A Generalized Adder mechanism for Cell Size Homeostasis: Implications for Stochastic Dynamics of Clonal Proliferation.

Measurements of cell size dynamics have revealed phenomeno-logical principles by which individual cells control their size across diverse organisms. One of the emerging paradigms of cell size homeostasis is the adder , where the cell cycle duration is established such that the cell size increase from birth to division is independent of the newborn cell size. We provide a mechanistic formulation of the adder considering that cell size follows any arbitrary non-exponential growth law . Our results show that the main requirement to obtain an adder regardless of the growth law (the time derivative of cell size) is that cell cycle regulators are produced at a rate proportional to the growth law and cell division is triggered when these molecules reach a prescribed threshold level. Among the implications of this generalized adder, we investigate fluctuations in the proliferation of single-cell derived colonies. Considering exponential cell size growth, random fluctuations in clonal size show a transient increase and then eventually decay to zero over time (i.e., clonal populations become asymptotically more similar). In contrast, several forms of non-exponential cell size dynamics (with adder-based cell size control) yield qualitatively different results: clonal size fluctuations monotonically increase over time reaching a non-zero value. These results characterize the interplay between cell size homeostasis at the single-cell level and clonal proliferation at the population level, explaining the broad fluctuations in clonal sizes seen in barcoded human cell lines.

Amitotic Cell Division, Malignancy, and Resistance to Anticancer Agents: A Tribute to Drs. Walen and Rajaraman.

Cell division is crucial for the survival of living organisms. Human cells undergo three types of cell division: mitosis, meiosis, and amitosis. The former two types occur in somatic cells and germ cells, respectively. Amitosis involves nuclear budding and occurs in cells that exhibit abnormal nuclear morphology (e.g., polyploidy) with increased cell size. In the early 2000s, Kirsten Walen and Rengaswami Rajaraman and his associates independently reported that polyploid human cells are capable of producing progeny via amitotic cell division, and that a subset of emerging daughter cells proliferate rapidly, exhibit stem cell-like properties, and can contribute to tumorigenesis. Polyploid cells that arise in solid tumors/tumor-derived cell lines are referred to as polyploid giant cancer cells (PGCCs) and are known to contribute to therapy resistance and disease recurrence following anticancer treatment. This commentary provides an update on some of these intriguing discoveries as a tribute to Drs. Walen and Rajaraman.

Quantitative label-free digital holographic imaging of cardiomyocyte optical volume, nucleation, and cell division

Cardiac regeneration in newborn rodents depends on the ability of pre-existing cardiomyocytes to proliferate and divide. This capacity is lost within the first week of postnatal development when these cells rapidly switch from hyperplasia to hypertrophy, withdraw from the cell cycle, become binucleated, and increase in size. How these dynamic changes in cell size and nucleation impact cardiomyocyte proliferative potential is not well understood. In this study, we innovate the application of a commercially available digital holographic imaging microscope, the Holomonitor M4, to evaluate the proliferative responses of mononucleated and binucleated cardiomyocytes after CHIR99021 treatment, a model proliferative stimulus. This system enables long-term label-free quantitative tracking of primary cardiomyocyte dynamics in real-time with single-cell resolution. Our results confirm that chemical inhibition of glycogen synthase kinase 3 with CHIR99021 promotes complete cell division of both mononucleated and binucleated cardiomyocytes with high frequency. Quantitative tracking of cardiomyocyte volume dynamics during these proliferative events revealed that both mononucleated and binucleated cardiomyocytes reach a similar size-increase threshold prior to attempted cell division. Binucleated cardiomyocytes attempt to divide with lower frequency than mononucleated cardiomyocytes, which may be associated with inadequate increases in cell size. By defining the interrelationship between cardiomyocyte size, nucleation, and cell cycle control, we may better understand the cellular mechanisms that drive the loss of mammalian cardiac regenerative capacity after birth.

An unscheduled switch to endocycles induces a reversible senescent arrest that impairs growth of the Drosophila wing disc.

A programmed developmental switch to G / S endocycles results in tissue growth through an increase in cell size. Unscheduled, induced endocycling cells (iECs) promote wound healing but also contribute to cancer. Much remains unknown, however, about how these iECs affect tissue growth. Using the D. melanogaster wing disc as model, we find that populations of iECs initially increase in size but then subsequently undergo a heterogenous arrest that causes severe tissue undergrowth. iECs acquired DNA damage and activated a Jun N-terminal kinase (JNK) pathway, but, unlike other stressed cells, were apoptosis-resistant and not eliminated from the epithelium. Instead, iECs entered a JNK-dependent and reversible senescent-like arrest. Senescent iECs promoted division of diploid neighbors, but this compensatory proliferation did not rescue tissue growth. Our study has uncovered unique attributes of iECs and their effects on tissue growth that have important implications for understanding their roles in wound healing and cancer.

Neuropeptide alpha-Melanocyte stimulating hormone preserves corneal endothelial morphology in a murine model of Fuchs dystrophy

Fuchs endothelial corneal dystrophy is a heterogenous disease with multifactorial etiology, and genetic, epigenetic, and exogenous factors contributing to its pathogenesis. DNA damage plays a significant role, with ultraviolet-A (UV-A) emerging as a key contributing factor. We investigate the potential application of neuropeptide α-melanocyte stimulating hormone (α-MSH) in mitigating oxidative stress induced endothelial damage. First, we examined the effects of α-MSH on a cultured human corneal endothelial cell line (HCEnC-21T) exposed to hydrogen peroxide (H2O2) induced oxidative DNA damage. We performed immunofluorescence and flow cytometry to assess DNA damage and cell death in the cultured cells. Additionally, we used an established mouse model that utilizes ultraviolet light to induce corneal endothelial cell damage resulting in decreased CEnC number, increased cell size variability, and decreased percentage of hexagonal cells. This endothelial decompensation leads to an increase in corneal thickness. Following UV-A exposure, the mice were systemically treated with α-MSH, either immediately after exposure (early treatment) or beginning two weeks post-exposure (delayed treatment). To evaluate treatment efficacy, we analyzed CEnC density and morphology using in vivo confocal microscopy, and central corneal thickness using anterior segment optical coherence tomography. Our findings demonstrated that α-MSH treatment effectively protects HCEnC-21T from free-radical induced oxidative DNA damage and subsequent cell death. In vivo, α-MSH treatment, mitigated the loss of CEnC density, deterioration of cell morphology and suppression of the resultant corneal swelling. These results underline the potential application of α-MSH as a therapeutic agent for mitigating corneal endothelial damage.

Enhancing [177Lu]Lu-DOTA-TATE therapeutic efficacy in vitro by combining it with metronomic chemotherapeutics

BackgroundPeptide receptor radionuclide therapy (PRRT) uses [177Lu]Lu-[DOTA0-Tyr3]octreotate ([177Lu]Lu-DOTA-TATE) to treat patients with neuroendocrine tumours (NETs) overexpressing the somatostatin receptor 2A (SSTR2A). It has shown significant short-term improvements in survival and symptom alleviation, but there remains room for improvement. Here, we investigated whether combining [177Lu]Lu-DOTA-TATE with chemotherapeutics enhanced the in vitro therapeutic efficacy of [177Lu]Lu-DOTA-TATE.ResultsTransfected human osteosarcoma (U2OS + SSTR2A, high SSTR2A expression) and pancreatic NET (BON1 + STTR2A, medium SSTR2A expression) cells were subjected to hydroxyurea, gemcitabine or triapine for 24 h at 37oC and 5% CO2. Cells were then recovered for 4 h prior to a 24-hour incubation with 0.7–1.03 MBq [177Lu]Lu-DOTA-TATE (25 nM) for uptake and metabolic viability studies. Incubation of U2OS + SSTR2A cells with hydroxyurea, gemcitabine, and triapine enhanced uptake of [177Lu]Lu-DOTA-TATE from 0.2 ± 0.1 in untreated cells to 0.4 ± 0.1, 1.1 ± 0.2, and 0.9 ± 0.2 Bq/cell in U2OS + SSTR2A cells, respectively. Cell viability post treatment with [177Lu]Lu-DOTA-TATE in cells pre-treated with chemotherapeutics was decreased compared to cells treated with [177Lu]Lu-DOTA-TATE monotherapy. For example, the viability of U2OS + SSTR2A cells incubated with [177Lu]Lu-DOTA-TATE decreased from 59.5 ± 22.3% to 18.8 ± 5.2% when pre-treated with hydroxyurea. Control conditions showed no reduced metabolic viability. Cells were also harvested to assess cell cycle progression, SSTR2A expression, and cell size by flow cytometry. Chemotherapeutics increased SSTR2A expression and cell size in U2OS + SSTR2A and BON1 + STTR2A cells. The S-phase sub-population of asynchronous U2OS + SSTR2A cell cultures was increased from 45.5 ± 3.3% to 84.8 ± 2.5%, 85.9 ± 1.9%, and 86.6 ± 2.2% when treated with hydroxyurea, gemcitabine, and triapine, respectively.ConclusionsHydroxyurea, gemcitabine and triapine all increased cell size, SSTR2A expression, and [177Lu]Lu-DOTA-TATE uptake, whilst reducing cell metabolic viability in U2OS + SSTR2A cells when compared to [177Lu]Lu-DOTA-TATE monotherapy. Further investigations could transform patient care and positively increase outcomes for patients treated with [177Lu]Lu-DOTA-TATE.

A metabolic perspective on polyploid invasion and the emergence of life histories: Insights from a mechanistic model.

Whole-genome duplication (WGD, polyploidization) has been identified as a driver of genetic and phenotypic novelty, having pervasive consequences for the evolution of lineages. While polyploids are widespread, especially among plants, the long-term establishment of polyploids is exceedingly rare. Genome doubling commonly results in increased cell sizes and metabolic expenses, which may be sufficient to modulate polyploid establishment in environments where their diploid ancestors thrive. We developed a mechanistic simulation model of photosynthetic individuals to test whether changes in size and metabolic efficiency allow autopolyploids to coexist with, or even invade, ancestral diploid populations. Central to the model is metabolic efficiency, which determines how energy obtained from size-dependent photosynthetic production is allocated to basal metabolism as opposed to somatic and reproductive growth. We expected neopolyploids to establish successfully if they have equal or higher metabolic efficiency as diploids or to adapt their life history to offset metabolic inefficiency. Polyploid invasion was observed across a wide range of metabolic efficiency differences between polyploids and diploids. Polyploids became established in diploid populations even when they had a lower metabolic efficiency, which was facilitated by recurrent formation. Competition for nutrients is a major driver of population dynamics in this model. Perenniality did not qualitatively affect the relative metabolic efficiency from which tetraploids tended to establish. Feedback between size-dependent metabolism and energy allocation generated size and age differences between plants with different ploidies. We demonstrated that even small changes in metabolic efficiency are sufficient for the establishment of polyploids.

Therapeutic Senolysis of Axitinib-Induced Senescent Human Lung Cancer Cells.

Tyrosine kinase inhibitors (TKIs) inhibit receptor-mediated signals in cells. Axitinib is a TKI with high specificity for vascular endothelial growth factor receptors (VEGFRs). We determined whether axitinib could induce senescence in human cancer cells and be lysed by the senolytic drug ABT-263. Human lung and breast adenocarcinoma cell lines were used. These cells were cultured with axitinib or a multi-target TKI lenvatinib. The expression of β-galactosidase, VEGFRs, Ki-67, reactive oxygen species (ROS) of cancer cells, and their BrdU uptake were evaluated by flow cytometry. The mRNA expression of p21 and IL-8 was examined by quantitative PCR. The effects of TKIs on phosphorylation of Akt and Erk1/2, as downstream molecules of VEGFR signaling, were examined by immunoblot. The in vivo anti-cancer effect was examined using a xenograft mice model. Axitinib, but not lenvatinib, induced cellular senescence (increased cell size and enhanced expression of β-galactosidase) in all adenocarcinoma cell lines. Axitinib-induced senescence was unrelated to the expression of VEGFRs on cancer cells. ROS were involved in axitinib-induced senescence. Axitinib-induced senescent lung adenocarcinoma A549 cells were drastically lysed by ABT-263. In A549-xenografted mice, combination therapy with axitinib and ABT-263 significantly suppressed tumor growth with the induction of apoptotic cancer cells.

3D Printed PLA Porous Scaffolds with Engineered Cell Size and Porosity Promote the Effectiveness of the Kelvin Model for Bone Tissue Engineering

AbstractIn this study, the aim is to investigate the effect of engineering the cell size and porosity of 3D‐printed poly lactic acid (PLA) porous scaffolds from the Kelvin model for bone tissue engineering applications. The Kelvin model is used as a bone tissue scaffold with different cell sizes and porosities. PLA, as a biodegradable and biocompatible polymer, is used to fabricate these scaffolds using the FDM technique. A compression test is used to evaluate the mechanical properties of scaffolds. The MTT assay has been used to investigate cell viability. For osteogenic differentiation studies, ALP activity and ARS assays are used. Increasing the porosity reduces the mechanical properties of the scaffold. While increasing the cell size at constant porosity increases the Young's modulus and yield stress in the samples, it is also observed that, in high porosities, the increase in cell size weakens the mechanical properties. Also, Kelvin model scaffolds help the proliferation and osteogenic differentiation of cells and have no toxic effect. It is demonstrated that this approach promotes the effectiveness of the Kelvin architecture for bone tissue engineering. As a result, designing the most suitable model based on cell size and porosity for the treatment process in the targeted area could be promising.

Abstract Tu082: Novel Structural and Biochemical Effects of Nexilin Associated Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is primarily a genetic disease that results in abnormal cardiac muscle phenotypes characterized by ventricular hypertrophy, fibrosis, and contractile dysfunction. Both sarcomere structural and signaling genes are associated with HCM. Among various genes, one of the implicated genes for HCM is Nexilin (NEXN). Nexilin is an F-actin binding protein widely expressed in muscle cells and localized at sarcomere and T-tubules. It is known to have a surprising role in insulin signaling. The role of Nexilin mutations is poorly studied. We hypothesized that Nexilin missense variants in genetically engineered human pluripotent stem cells (hPSCs) perturb essential cardiac metabolic signaling pathways leading to HCM. In our Indian HCM cohort, we identified seven Nexilin mutations through exome sequencing and categorized them as pathogenic per ACMG/AMP classification. A representative novel mutant in Nexilin p.Q131T was introduced in hPSC with the CRISPR-Cas9 knock-in method and was differentiated into cardiomyocytes, recapitulating patient-specific heterozygous mutation. Our data shows that Nexilin p.Q131T causes an increase in cell size and activation of fetal gene transcriptional programs in hPSC-derived cardiomyocytes. Global transcriptomics was performed to understand transcriptional changes and investigate further. We observe the significant activation of insulin-related signaling pathways, including AKT/MTOR and MAPK, confirmed by immunoblotting. Akt-mTOR and MAPK cascades are well-known to be regulated by IRS-1 signaling. Our studies show hyperactivation of these cascades, suggesting IRS-1 involvement in the pathogenesis. Nexilin and IRS-1 interaction were probed and found to be perturbed, hence causing higher activation of IRS-1 and its downstream targets. In addition, Nexilin wild type and mutant protein structure-functional analysis were performed with purified proteins. Using cryo-EM structural analysis, we identified unique F-actin binding sites for Nexilin for the first time, and the mutant p.Q131T showed decreased binding affinity to F-actin. We report Nexilin's high-resolution cryo-EM structure and a novel metabolic signaling mechanism where mutations in Nexilin cause dysregulation of IRS-1 signaling in the gene-edited cardiomyocytes, leading to HCM pathogenesis.

The immediate metabolomic effects of whole-genome duplication in the greater duckweed, Spirodela polyrhiza.

In plants, whole-genome duplication (WGD) is a common mutation with profound evolutionary potential. Given the costs associated with a superfluous genome copy, polyploid establishment is enigmatic. However, in the right environment, immediate phenotypic changes following WGD can facilitate establishment. Metabolite abundances are the direct output of the cell's regulatory network and determine much of the impact of environmental and genetic change on the phenotype. While it is well known that an increase in the bulk amount of genetic material can increase cell size, the impact of gene dosage multiplication on the metabolome remains largely unknown. We used untargeted metabolomics on four genetically distinct diploid-neoautotetraploid pairs of the greater duckweed, Spirodela polyrhiza, to investigate how WGD affects metabolite abundances per cell and per biomass. Autopolyploidy increased metabolite levels per cell, but the response of individual metabolites varied considerably. However, the impact on metabolite level per biomass was restricted because the increased cell size reduced the metabolite concentration per cell. Nevertheless, we detected both quantitative and qualitative effects of WGD on the metabolome. Many effects were strain-specific, but some were shared by all four strains. The nature and impact of metabolic changes after WGD depended strongly on the genotype. Dosage effects have the potential to alter the plant metabolome qualitatively and quantitatively, but were largely balanced out by the reduction in metabolite concentration due to an increase in cell size in this species.

Direct and indirect cumulative effects of temperature, nutrients, and light on phytoplankton growth.

Temperature and resource availability are pivotal factors influencing phytoplankton community structures. Numerous prior studies demonstrated their significant influence on phytoplankton stoichiometry, cell size, and growth rates. The growth rate, serving as a reflection of an organism's success within its environment, is linked to stoichiometry and cell size. Consequently, alterations in abiotic conditions affecting cell size or stoichiometry also exert indirect effects on growth. However, such results have their limitations, as most studies used a limited number of factors and factor levels which gives us limited insights into how phytoplankton respond to environmental conditions, directly and indirectly. Here, we tested for the generality of patterns found in other studies, using a combined multiple-factor gradient design and two single species with different size characteristics. We used a structural equation model (SEM) that allowed us to investigate the direct cumulative effects of temperature and resource availability (i.e., light, N and P) on phytoplankton growth, as well as their indirect effects on growth through changes in cell size and cell stoichiometry. Our results mostly support the results reported in previous research thus some effects can be identified as dominant effects. We identified rising temperature as the dominant driver for cell size reduction and increase in growth, and nutrient availability (i.e., N and P) as dominant factor for changes in cellular stoichiometry. However, indirect effects of temperature and resources (i.e., light and nutrients) on species' growth rates through cell size and cell stoichiometry differed across the two species suggesting different strategies to acclimate to its environment.