Phenotypic Changes Research Articles

Vesicle-Transported Multidrug Resistance as a Possible Therapeutic Target of Natural Compounds.

A key role of extracellular vesicles (EVs) is mediating both cell-cell and cell-stroma communication in pathological/physiological conditions. EVs from resistant tumor cells can transport different molecules like P-glycoprotein (P-gp), acting as a shuttle between donor and recipient cells, resulting in a phenotypic change. The aim of our work was to isolate, characterize, and inhibit the release of EVs in two multidrug resistance (MDR) cancer models: MCF-7R (breast cancer cell line) and HL-60R (acute myeloid leukemia cell line). The existence of P-gp in EVs from MDR cells was confirmed by Western blotting assays. The characterization of EVs was carried out by evaluating the size using NTA and the presence of specific markers such as CD63, Hsp70 and Syntenin. The ability of HL-60R and MCF-7R to perform horizontal transfer of P-gp via EVs to sensitive cells was assessed using three different methods. The acquisition of resistance and its inhibition in recipient cells was confirmed by MTS 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Our data showed that cell lines (MDR) release P-gp-loaded EVs, unlike sensitive cells. The acquisition of resistance determined by the incorporation of P-gp into the membrane of sensitive cells was confirmed by the reduced cytotoxic activity of doxorubicin. Natural compounds such as curcumin, lupeol, and heptacosane can block vesicular transfer and restore the sensitivity of HL-60 and MCF-7 cells. Our study demonstrates that natural inhibitors able to reverse this mechanism may represent a new therapeutic strategy to limit the propagation of the resistant phenotype.

Exogenous Melatonin Reinforces Photosynthesis, Antioxidant Defense and Gene Expression to Ameliorate Na2CO3 Stress in Maize.

Salt stress can seriously affect the growth and development of maize (Zea mays L.), resulting in a great yield loss. Melatonin (MT), an indole hormone, is a potential enhancer of plant tolerance against salt stress. However, the complex mechanisms of MT application in enhancing maize salt tolerance are still unclear. Herein, three-leaf seedlings of salt-susceptible P138 and its salt-resistant ethyl methane sulfonate (EMS)-104 mutant were cultured with or without 150 μM MT application under 0 and 100 mM Na2CO3 treatments for seven days, to systematically explore the response mechanisms of exogenous MT in improving the salt tolerance of maize. The results showed that salt stress triggered an escalation in reactive oxygen species production, enhanced multiple antioxidant enzymes' activities, impaired cellular membrane permeability, inhibited photosynthetic pigment accumulation, and ultimately undermined the vigor and photosynthetic prowess of the seedlings. While suitable MT application counteracted the detrimental impacts of Na2CO3 on seedlings' growth and photosynthetic capacity, the seedling length and net photosynthetic rate of P138 and EMS-104 were increased by 5.5% and 18.7%, and 12.7% and 54.5%, respectively. Quantitative real-time PCR (qRT-PCR) analysis further showed that MT application activated the expression levels of antioxidant enzyme-related genes (Zm00001d025106, Zm00001d031908, Zm00001d027511, and Zm00001d040364) and pigment biosynthesis-related genes (Zm00001d011819 and Zm00001d017766) in both maize seedlings under Na2CO3 stress; they then formed a complex interaction network of gene expression, multiple physiological metabolisms, and phenotype changes to influence the salt tolerance of maize seedlings under MT or Na2CO3 stress. To sum up, these observations underscore that 150 μM MT can alleviate salt injury of maize seedlings, which may provide new insights for further investigating MT regulation mechanisms to enhance maize seedlings' salt resistance.

SnRNA-seq reveals differential functional transcriptional pathway alterations in three mutant types of dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a leading cause of heart failure, characterized by ventricular dilation, thinning of the ventricular walls, and systolic dysfunction in either the left or both ventricles, often accompanied by fibrosis. Human cardiac tissue is composed of various cell types, including cardiomyocytes (CMs), fibroblasts (FBs), endothelial cells (ECs), macrophages, lymphocytes and so on. In DCM patients, these cells frequently undergo functional and phenotypic changes, contributing to contractile dysfunction, inflammation, fibrosis, and cell death, thereby increasing the risk of heart failure. This study focuses on DCM patients with mutations (LMNA, RBM20, and TTN) and analyzes functional changes in subpopulations of four cardiac cell types. The study involves functional annotation of subpopulations within each cell type and explores the association between gene mutations and specific functions and pathways. Additionally, the SCENIC method is employed of a particular cell subpopulation with significant functional importance, aiming to identify key transcriptional regulators in specific cell states. By analyzing the expression levels of ligand-receptor pairs in vCM4, vFB2, EC5.0, T cells, and NK cells across the DCM mutant genotypes, we predicted their signaling pathways and communications. This research provides insights into the molecular mechanisms of DCM and potential therapeutic targets.

Ecological adaptations of amphibians to environmental changes along an altitudinal gradient (Case Study: Bufo gargarizans) from phenotypic and genetic perspectives

BackgroundOrganisms have evolved a range of phenotypic and genetic adaptations to live in different environments along an altitudinal gradient. Herein, we studied the widely distributed Chinese toad, Bufo gargarizans, as a model and used an integrated phenotype-genotype approach to assess adaptations to different altitudinal environments.ResultsComparison of populations from four altitudes (50 m, 1200 m, 2300 m, and 3400 m) showed more effective defenses among high-altitude toads. These included thickened epidermis, more epidermal capillaries and granular glands, greater gland size in skin, and higher antioxidant enzyme activities in plasma. High-altitude toads also showed increased erythrocytes and hematocrit and elevated hemoglobin concentration, potentially improving oxygen delivery. Elevated altitude led to a metabolic shift from aerobic to anaerobic metabolism, and high-altitude populations favored carbohydrates over fatty acids to fuel for energy metabolism. Differentially expressed genes were associated with adaptive phenotypic changes. For instance, expression of genes associated with fatty acid metabolism showed greater suppression at high altitude (3400 m), consistent with decreased flux of β-hydroxybutyric acid and lower free fatty acids levels. Moreover, down-regulation of genes involved in carbon metabolism processes at high altitude (3400 m) were coincident with reduced TCA cycle flux. These results suggest that high-altitude toads adopt a metabolic suppression strategy for survival under harsh environmental conditions. Moreover, the hypoxia-inducible factor signaling cascade was activated at high altitude.ConclusionsCollectively, these results advance our comprehension of adaptation to high-altitude environments by revealing physiological and genetic mechanisms at work in Chinese toads living along altitudinal gradients.

Type 1 spinal muscular atrophy treated with nusinersen in Norway, a five-year follow-up

BackgroundNew treatments for 5q spinal muscular atrophy (SMA) have led to changes in the disease phenotype. Questions about long-term efficacy, however, persist. We present the results from five-year follow-up of the first ten Norwegian patients with SMA type1 treated with nusinersen. Methods– Ten patients referred to the expanded access program were included. Standardized assessments with Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), the Hammersmith Infant Neurological Examination (HINE-2), compound muscle action potential (CMAP) examination and cerebrospinal fluid analysis of neurofilament light chain (cNfL) were performed. ResultAge at baseline ranged from three months to 11 years and eight months. Nine patients were alive and continued to receive treatment at 62 months of follow-up. CHOP INTEND scores increased significantly up to 38 months. Any further increase from 38 to 50 months was not statistically significant, and scores remained almost unchanged from 50 to 62 months. HINE-2 scores increased but the difference from baseline never reached statistical significance.The youngest patients showed the best motor outcome. The changes in CMAP scores were not statistically significant. cNfL values were significantly reduced after 18 months compared with baseline; the largest difference occurred between baseline and 6 months. There was a significant negative correlation between log cNfL and CHOP INTEND (p = 0.042). Bulbar and respiratory function did not improve during the observation period. ConclusionOur findings support previously reported results on efficacy and safety of nusinersen. All patients have shown improvement in motor function. The need of respiratory and nutritional support did not improve.

Cellular resiliency and survival of Neuro-2a cells under extreme stress

Stressors such as hypoxia, hypothermia, and acute toxicity often result in widespread cell death. This study investigated the outcomes of Neuro-2a (N2a; mouse neuroblastoma) cells following a cryogenic storage failure that exposed them to a combination of these stressors over a period of approximately 24-30 hours. Remarkably, a small fraction of the cells survived the event, underwent a period of dormancy, and eventually recovered to a healthy state. To understand the underlying resilience mechanisms, we created a model to replicate the dewar failure event and examined changes in phenotype, transcriptomics, proteomics, and mitochondrial activity of the surviving cells during recovery. We found that the surviving cells initially displayed a stressed morphology with irregular membranes and a clustered apperance. They showed an increased expression of proteins related to DNA repair and chromatin modification pathways as well as heightened mitochondrial function shortly after the stress event. As recovery progressed, the stress-responsive pathways, mitochondrial activity, and growth rates normalized toward that of healthy controls, indicating a return to a stable baseline state. These findings suggest that an initial robust energetic state supports key stress-responsive and repair pathways at the early stages of recovery, facilitating cell survival and resiliency after extreme stress. This work provides valuable insights into cellular resilience mechanisms with potential implications for improving cell preservation and recovery in biomedical applications and developing therapeutic strategies for conditions involving cell damage and stress.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions.

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Combinatorial prediction of therapeutic perturbations using causally-inspired neural networks.

As an alternative to target-driven drug discovery, phenotype-driven approaches identify compounds that counteract the overall disease effects by analyzing phenotypic signatures. Our study introduces a novel approach to this field, aiming to expand the search space for new therapeutic agents. We introduce PDGrapher, a causally-inspired graph neural network (GNN) designed to predict combinatorial perturbagens - sets of therapeutic targets - capable of reversing disease effects. Unlike methods that learn responses to perturbations, PDGrapher solves the inverse problem, which is to infer the perturbagens necessary to achieve a specific response - i.e., directly predicting perturbagens by learning which perturbations elicit a desired response. By encoding gene regulatory networks or protein-protein interactions, PDGrapher can predict unseen chemical or genetic perturbagens, aiding in the discovery of novel drugs or therapeutic targets. Experiments across nine cell lines with chemical perturbations show that PDGrapher successfully predicted effective perturbagens in up to 13.33% additional test samples and ranked therapeutic targets up to 35% higher than the competing methods, and the method shows competitive performance across ten genetic perturbation datasets. A key innovation of PDGrapher is its direct prediction capability, which contrasts with the indirect, computationally intensive models traditionally used in phenotype-driven drug discovery that only predict changes in phenotypes due to perturbations. The direct approach enables PDGrapher to train up to 25 times faster than methods like scGEN and CellOT, representing a considerable leap in efficiency. Our results suggest that PDGrapher can advance phenotype-driven drug discovery, offering a fast and comprehensive approach to identifying therapeutically useful perturbations.

Chlorophyll and Carotenoid Metabolism Varies with Growth Temperatures among Tea Genotypes with Different Leaf Colors in Camellia sinensis

The phenotype of albino tea plants (ATPs) is significantly influenced by temperature regimes and light conditions, which alter certain components of the tea leaves leading to corresponding phenotypic changes. However, the regulatory mechanism of temperature-dependent changes in photosynthetic pigment contents and the resultant leaf colors remain unclear. Here, we examined the chloroplast microstructure, shoot phenotype, photosynthetic pigment content, and the expression of pigment synthesis-related genes in three tea genotypes with different leaf colors under different temperature conditions. The electron microscopy results revealed that all varieties experienced the most severe chloroplast damage at 15 °C, particularly in albino cultivar Baiye 1 (BY), where chloroplast basal lamellae were loosely arranged, and some chloroplasts were even empty. In contrast, the chloroplast basal lamellae at 35 °C and 25 °C were neatly arranged and well-developed, outperforming those observed at 20 °C and 15 °C. Chlorophyll and carotenoid measurements revealed a significant reduction in chlorophyll content under low temperature treatment, peaking at ambient temperature followed by high temperatures. Interestingly, BY showed remarkable tolerance to high temperatures, maintaining relatively high chlorophyll content, indicating its sensitivity primarily to low temperatures. Furthermore, the trends in gene expression related to chlorophyll and carotenoid metabolism were largely consistent with the pigment content. Correlation analysis identified key genes responsible for temperature-induced changes in these pigments, suggesting that changes in their expression likely contribute to temperature-dependent leaf color variations.

Exploring the complex immunomodulatory effects and gut defense via oral administration of Astragali radix water extract to normal mice

BackgroundAstragali radix (AR) is one of the most widely used traditional Chinese herbal medicines. It exhibits diverse biological activities, including immunomodulatory and anti-inflammatory properties; however, some of its activities have only been demonstrated in vitro.ObjectiveTo examine the effects of orally administered AR extract on immune cells and the intestine under physiological conditions, which bridges the gap between previously observed in vitro outcomes and in vivo results.MethodsAR extract was prepared by hot water extraction. Three separate animal experiments were conducted to isolate macrophages, splenocytes, and the small intestine epithelium. For the macrophage preparation experiment, an intraperitoneal injection of sterile thioglycolate was administered. The mice received oral AR extract at doses of 0.1, 0.5, or 2.5 g/kg for ten days. At the end of each experiment, cells or tissues were isolated. A portion of macrophages and splenocytes were analyzed for the phenotypic changes. The remaining cells were cultured and stimulated with lipopolysaccharide (LPS) or mitogen ex vivo to assess activation status, proliferation, and cytokine production. Samples of the intestine were subjected to real-time RT-PCR.ResultsPeritoneal macrophages from AR-treated mice exhibited increased expression of scavenger receptors, including SRA and CD36. Stimulation of these macrophages ex vivo with LPS selectively modulated the inflammatory response, including reduced expression of the costimulatory molecules CD40 and CD86, which are important for T cell responses, without affecting TNF-α and IL-6 production. Splenocytes from AR-treated mice exhibited a dose-dependent increase in CD4 and CD8 T cells; however, stimulation with mitogen decreased T cell proliferation and reduced IFN-γ production, which is essential for macrophage activation. An analysis of the small intestinal epithelium revealed an attenuated antimicrobial response, including reduced IgA content in the lumen and decreased expression of mucin-2 and polymeric Ig receptor genes.ConclusionThe response of immune cells following oral treatment with AR extract did not replicate the previously documented in vitro findings. Immune cells and intestinal epithelium from mice administered oral AR extract exhibited a selective anti-inflammatory phenotype. The overall findings indicate that the systemic effects after oral administration of AR extract include reduced sensitivity to inflammatory insults.

Features of subset composition and functional activity of blood lymphocytes in tick-borne infections of different etiologies

Aim. To perform a comparative assessment of subset composition and functional activity of peripheral blood lymphocytes in patients with tick-borne encephalitis (TBE) and ixodid tick-borne borreliosis (ITBB) in the acute phase of the disease.Materials and methods. The study involved 22 patients with febrile and meningeal TBE, 15 patients with ITBB with and without erythema, and 11 healthy controls. Subset composition of blood lymphocytes was determined by flow cytometry. The blast transformation assay was applied to assess lymphocyte proliferation. Cytokine-producing activity of cells was studied in 24-hour incubated mononuclear cell cultures. Cytokine concentrations (interleukin (IL)-2, IL-4, IL-10, interferon (IFN)γ) were determined in the supernatants by the enzyme-linked immunosorbent assay (ELISA).Results. Patients with TBE demonstrated an increase in the proportion of helper – inducer T-cells, a pronounced decrease in the proportion and absolute count of cytotoxic T cells, and low T lymphocyte count compared to the control values. The study in ITBB patients revealed an increase in the helper – inducer T-cell count and the proportion of NK-cells, a decrease in the cytotoxic T cell count, and the T lymphocyte count comparable to normal values. The most significant decrease in the levels of phytohemagglutinin-induced lymphocyte proliferation was found in patients with TBE. Patients of both groups showed a decrease in IL-2 secretion in the mononuclear cell culture, a rise in IL-4 and IL-10 production, and IFNγ production levels comparable to control values.Conclusion. The study of TBE patients revealed relative lymphocytopenia with changes in the subset composition of lymphocytes characterized by an increase in the proportion of helper – inducer T-cells and a decrease in the absolute cytotoxic T lymphocyte count. Patients with ITBB demonstrated an increase in the proportion of NK-cells and a more pronounced imbalance in the T-helper / cytotoxic T lymphocyte ratio. Changes in the functional phenotype of lymphocytes, regardless of the etiology of tick-borne infection, were characterized by reduced proliferative reserve, low IL-2 secretion, increased IL-4 and IL-10 production, and depressed reactivity of lymphocytes with respect to IFNγ secretion.

Commonalities of platelet dysfunction in heart failure with preserved ejection fraction and underlying comorbidities.

Heart failure with preserved ejection fraction (HFpEF) is characterized by a lack of a specific targeted treatment and a complex, partially unexplored pathophysiology. Common comorbidities associated with HFpEF are hypertension, atrial fibrillation, obesity and diabetes. These comorbidities, combined with advanced age, play a crucial role in the initiation and development of the disease through the promotion of systemic inflammation and consequent changes in cardiac phenotype. In this context, we suggest platelets as important players due to their emerging role in vascular inflammation. This review provides an overview of the role of platelets in HFpEF and its associated comorbidities, including hypertension, atrial fibrillation, obesity and diabetes mellitus, as well as the impact of age and sex on platelet function. These major HFpEF-associated comorbidities present alterations in platelet behaviour and in features linked to platelet size, content and reactivity. The resulting dysfunctional platelets can contribute to further increase inflammation, oxidative stress and endothelial dysfunction, suggesting an active role of these cells in the initiation and progression of HFpEF. Recent evidence shows that reduced platelet count and elevated mean platelet volume are associated with worsening heart failure in HFpEF patients. However, the specific mechanisms by which platelets contribute to HFpEF development and progression are still largely unexplored, with only a few studies investigating platelet function in HFpEF. We discuss the limited yet significant body of research investigating platelet function in HFpEF, emphasizing the need for more comprehensive studies. Additionally, we explore the potential mechanisms through which platelets may influence HFpEF, such as their interactions with the vascular endothelium and the secretion of bioactive molecules like cytokines, chemokines and RNA molecules. These interactions and secretions may play a role in modulating vascular inflammation and contributing to the pathophysiological landscape of HFpEF. The review underscores the necessity for future research to elucidate the precise contributions of platelets to HFpEF, aiming to potentially identify novel therapeutic targets and improve patient outcomes. The evidence presented herein supports the hypothesis that platelets are not merely passive bystanders but active participants in the pathophysiology of HFpEF and its comorbidities.

Efficient Regeneration of Transgenic Rice from Embryogenic Callus via Agrobacterium-Mediated Transformation: A Case Study Using GFP and Apple MdFT1 Genes

Genetic transformation is a critical tool for gene manipulation and functional analyses in plants, enabling the exploration of key phenotypes and agronomic traits at the genetic level. While dicotyledonous plants offer various tissues for in vitro culture and transformation, monocotyledonous plants, such as rice, have limited options. This study presents an efficient method for genetically transforming rice (Oryza sativa L.) using seed-derived embryogenic calli as explants. Two target genes were utilized to assess regeneration efficiency: green fluorescent protein (eGFP) and the apple FLOWERING LOCUS T (FT)-like gene (MdFT1). Antisense MdFT1 was cloned into a vector controlled by the rice α-amylase 3D (Ramy3D) promoter, while eGFP was fused to Cas9 under the Ubi promoter. These vectors were introduced separately into rice embryogenic calli from two Korean cultivars using Agrobacterium-mediated transformation. Transgenic seedlings were successfully regenerated via hygromycin selection using an in vitro cultivation system. PCR confirmed stable transgene integration in the transgenic calli and their progeny. Fluorescence microscopy revealed eGFP expression, and antisense MdFT1-expressing lines exhibited notable phenotypic changes, including variations in plant height and grain quality. High transformation efficiency and regeneration frequency were achieved for both tested cultivars. This study demonstrated the effective use of seed-derived embryogenic calli for rice transformation, offering a promising approach for developing transgenic plants in monocot species.

8786 Novel TGFbeta Ligand Regulated Genes in WT and FSTL3 KO Testis Identified by ChIP-Seq Analysis: Implications for Signalling Cross-talk

Abstract Disclosure: R. Ballesteros: None. A. Mukherjee: None. Folistatin Like 3 (FSTL3) is a known antagonist of activin and myostatin action that when deleted from the mouse genome displayed a set of phenotypic changes that are directly linked to glucose metabolism and reproductive function. Although our previous work showed that β-cell hyperplasia, increased pancreatic islet number and size and reduced visceral fat seen in FSTL3 knockout mice (FSTL3 KO) could be explained by enhanced activin and myostatin action, the molecular bases of the changes in the reproductive function seen in this mouse model remain elusive. In contrast to testicular degeneration produced by INHBA (activin A) transgenic overexpression in mice, deletion of FSTL3 results in increased testicular size, with increased Sertoli cell numbers and early meiotic entry of the first spermatogenic wave. This suggests a possibility that the phenotype in FSTL3 deleted mice might involve alteration of additional transcripts other than those induced by activin alone in the testis. To identify transcripts induced in FSTL3 deleted testis as a consequence of induced TGFβ ligand action we performed sequencing of Smad4 Chromatin immunoprecipitation (ChIP-Seq) from postnatal (3d) and post-pubertal (56d) whole testis. Our results show high activity of Smad4 signalling during postnatal stages compared to post-pubertal stages in both genotypes (Fstl3-KO vs wild-type). Interestingly, postnatal testis from FSTL3 KO contains significantly less activity from Smad4 signalling (69 peaks) compared to wild type (775 peaks). By contrast, on the whole, Smad4 signalling in post-pubertal stages is less active with 34 peaks in wild-type and 29 peaks in Fstl3-KO of which 8 genes are SMAD activated in both genotypes. To identify whether SMAD-dependent signalling produces significant differences in RNA expression, we then used the list of genes that generated peaks in the Smad4-ChIP-Seq experiment to filter our RNA-Seq data generated in a parallel experiment followed by differential gene expression analysis of GO terms by GSEA in postnatal testis from both genotypes. We found that Smad4-interacting genes in posnatal FSTL3 KO testis generate enrichment of 13 pathways including the androgen receptor signalling pathway. Taken together so far, our findings reveal a novel catalogue of SMAD-regulated genes in the testis, identifies a set of genes specifically upregulated in the testis in a SMAD-dependent manner upon FSTL3 deletion and also identify possible cross-talk between TGFβ and 13 other signalling pathways. Currently we are further analysing our data to identify whether there are SMAD regulated genes and pathways common in postnatal and postpubertal testes. We are also undertaking experiments to investigate expression pattern in FSTL3 KO testis to identify which pathways might specifically affect Sertoli cell proliferation and activity. Presentation: 6/2/2024

8786 Novel TGFbeta Ligand Regulated Genes in WT and FSTL3 KO Testis Identified by ChIP-Seq Analysis: Implications for Signalling Cross-talk

Abstract Disclosure: R. Ballesteros: None. A. Mukherjee: None. Folistatin Like 3 (FSTL3) is a known antagonist of activin and myostatin action that when deleted from the mouse genome displayed a set of phenotypic changes that are directly linked to glucose metabolism and reproductive function. Although our previous work showed that β-cell hyperplasia, increased pancreatic islet number and size and reduced visceral fat seen in FSTL3 knockout mice (FSTL3 KO) could be explained by enhanced activin and myostatin action, the molecular bases of the changes in the reproductive function seen in this mouse model remain elusive. In contrast to testicular degeneration produced by INHBA (activin A) transgenic overexpression in mice, deletion of FSTL3 results in increased testicular size, with increased Sertoli cell numbers and early meiotic entry of the first spermatogenic wave. This suggests a possibility that the phenotype in FSTL3 deleted mice might involve alteration of additional transcripts other than those induced by activin alone in the testis. To identify transcripts induced in FSTL3 deleted testis as a consequence of induced TGFβ ligand action we performed sequencing of Smad4 Chromatin immunoprecipitation (ChIP-Seq) from postnatal (3d) and post-pubertal (56d) whole testis. Our results show high activity of Smad4 signalling during postnatal stages compared to post-pubertal stages in both genotypes (Fstl3-KO vs wild-type). Interestingly, postnatal testis from FSTL3 KO contains significantly less activity from Smad4 signalling (69 peaks) compared to wild type (775 peaks). By contrast, on the whole, Smad4 signalling in post-pubertal stages is less active with 34 peaks in wild-type and 29 peaks in Fstl3-KO of which 8 genes are SMAD activated in both genotypes. To identify whether SMAD-dependent signalling produces significant differences in RNA expression, we then used the list of genes that generated peaks in the Smad4-ChIP-Seq experiment to filter our RNA-Seq data generated in a parallel experiment followed by differential gene expression analysis of GO terms by GSEA in postnatal testis from both genotypes. We found that Smad4-interacting genes in posnatal FSTL3 KO testis generate enrichment of 13 pathways including the androgen receptor signalling pathway. Taken together so far, our findings reveal a novel catalogue of SMAD-regulated genes in the testis, identifies a set of genes specifically upregulated in the testis in a SMAD-dependent manner upon FSTL3 deletion and also identify possible cross-talk between TGFβ and 13 other signalling pathways. Currently we are further analysing our data to identify whether there are SMAD regulated genes and pathways common in postnatal and postpubertal testes. We are also undertaking experiments to investigate expression pattern in FSTL3 KO testis to identify which pathways might specifically affect Sertoli cell proliferation and activity. Presentation: 6/2/2024

Mechanical Loading Modulates AMPK and mTOR Signaling in Muscle Cells.

Skeletal muscle adaptation to exercise involves various phenotypic changes that enhance the metabolic and contractile functions. One key regulator of these adaptive responses is the activation of AMPK, which is influenced by exercise intensity. However, the mechanistic understanding of AMPK activation during exercise remains incomplete. In this study, we utilized an in vitro model to investigate the effects of mechanical loading on AMPK activation and its interaction with the mTOR signaling pathway. Proteomic analysis of muscle cells subjected to static loading (SL) revealed distinct quantitative protein alterations associated with RNA metabolism, with 10% SL inducing the most pronounced response compared to lower intensities of 5% and 2% as well as the control. Additionally, 10% SL suppressed RNA and protein synthesis while activating AMPK and inhibiting the mTOR pathway. We also found that SRSF2, necessary for pre-mRNA splicing, is regulated by AMPK and mTOR signaling, which, in turn, is regulated in an intensity-dependent manner by SL with the highest expression in 2% SL. Further examination showed that the ADP/ATP ratio was increased after 10% SL compared to the control and that SL induced changes in mitochondrial biogenesis. Furthermore, Seahorse assay results indicate that 10% SL enhances mitochondrial respiration. These findings provide novel insights into the cellular responses to mechanical loading and shed light on the intricate AMPK-mTOR regulatory network in muscle cells.

Characteristics of autosomal dominant WFS1-associated optic neuropathy and its comparability to OPA1-associated autosomal dominant optic atrophy

This study aims to describe the ophthalmic characteristics of autosomal dominant (AD) WFS1-associated optic atrophy (AD WFS1-OA), and to explore phenotypic differences with dominant optic atrophy (DOA) caused by mutations in the OPA1-gene. WFS1-associated diseases, or ‘wolframinopathies’, exhibit a spectrum of ocular and systemic phenotypes, of which the autosomal recessive Wolfram syndrome has been the most extensively studied. AD mutations in WFS1 also cause various phenotypical changes including OA. The most common phenotype in AD WFS1-associated disease, the combination of OA and hearing loss (HL), clinically resembles the ‘plus’ phenotype of DOA. We performed a comprehensive medical record review across tertiary referral centers in the Netherlands and Belgium resulting in 22 patients with heterozygous WFS1 variants. Eighteen (82%) had HL in addition to OA. Diabetes mellitus was found in 7 (32%). Four patients had isolated OA. One patient had an unusual phenotype with anterior chamber abnormalities and malformations of the extremities. Compared to DOA, AD WFS1-OA patients had different color vision abnormalities (red-green vs blue-yellow in DOA), abnormal OPL lamination on macular OCT (absent in DOA), more generalized thinning of the retinal nerve fiber layer, and more reduced and delayed pattern reversal visual evoked potentials.

NUPR1 modulates pulmonary embolism progression via smooth muscle cells phenotypic transformation

ObjectiveThis study aimed to investigate the role of Nuclear Protein 1 (NUPR1) in pulmonary embolism (PE) and its impact on the phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs). MethodsA PE model was established via autologous pulmonary emboli infusion into the jugular vein. Partial Pressure of Oxygen (PaO2), Oxygenation Index (OI), Brain Natriuretic Peptide (BNP), and Troponin I (TnI) were measured, and lung tissue was subjected to hematoxylin-eosin (HE) staining. NUPR1 expression was assessed through Immunofluorescence and Western blot analyses. To investigate role of NUPR1, PE rats were treated with lentiviral vectors for NUPR1 knockdown (si-NUPR1) or overexpression (ov-NUPR1), and the effects on lung pathology were examined. NUPR1 expression was evaluated in human PASMCs. Additionally, PASMCs from SD rats were cultured under normoxic and hypoxic conditions to evaluate NUPR1 expression. Transfection of NUPR1 expression vectors into PASMCs allowed monitoring of phenotypic transformation-associated protein changes and PASMCs activity. ResultsIncreased NURP1 was observed in human-derived PASMCs. In PE rats, histological examination revealed ruptured pulmonary alveoli, exudate accumulation, interstitial edema, and infiltration of inflammatory cells, concomitant with elevated NUPR1 expression levels. Knockdown of NUPR1 in PE rats significantly improved lung tissue structure, reducing alveolar rupture and interstitial edema. Conversely, NUPR1 overexpression exacerbated lung damage, leading to increased inflammatory infiltration. NUPR1 expression in rat PASMCs remained stable under normoxic conditions; however, under hypoxic conditions, NUPR1 protein expression increased progressively over time. Subsequent upregulation of NUPR1 expression led to a decrease in the levels of contractile phenotype markers α-SMA and SM22α in PASMCs, accompanied by increased expression of synthetic phenotype markers Vimentin and OPN. This phenotypic shift was associated with enhanced cellular proliferation, invasion, and migration. ConclusionsElevated NUPR1 expression in PE exacerbates abnormal PASMCs proliferation by promoting their phenotypic transformation, thereby fostering the pathological progression of PE.

LRP1 Repression by SNAIL Results in ECM Remodeling in Genetic Risk for Vascular Diseases.

Genome-wide association studies implicate common genetic variations in the LRP1 (low-density lipoprotein receptor-related protein 1) locus at risk for multiple vascular diseases and traits. However, the underlying biological mechanisms are unknown. Fine mapping analyses included Bayesian colocalization to identify the most likely causal variant. Human induced pluripotent stem cells were genome-edited using CRISPR-Cas9 to delete or modify candidate enhancer regions and generate LRP1 knockout cell lines. Cells were differentiated into smooth muscle cells through a mesodermal lineage. Transcription regulation was assessed using luciferase reporter assay, transcription factor knockdown, and chromatin immunoprecipitation. Phenotype changes in cells were conducted using cellular assays, bulk RNA sequencing, and mass spectrometry. Multitrait colocalization analyses pointed at rs11172113 as the most likely causal variant in LRP1 for fibromuscular dysplasia, migraine, pulse pressure, and pulmonary function trait. We found the rs11172113-T allele to associate with higher LRP1 expression. Genomic deletion in induced pluripotent stem cell-derived smooth muscle cells supported rs11172113 to locate in an enhancer region regulating LRP1 expression. We found transcription factors MECP2 (methyl CpG binding protein 2) and SNAIL to repress LRP1 expression through an allele-specific mechanism, involving SNAIL interaction with disease risk allele. LRP1 knockout decreased induced pluripotent stem cell-derived smooth muscle cell proliferation and migration. Differentially expressed genes were enriched for collagen-containing extracellular matrix, connective tissue development, and lung development. LRP1 knockout and deletion of rs11172113 enhancer showed potentiated canonical TGF-β (transforming growth factor beta) signaling through enhanced phosphorylation of SMAD2/3. Analyses of the protein content of decellularized extracts indicated partial extracellular matrix remodeling involving enhanced secretion of CYR61, a known LRP1 ligand involved in vascular integrity and TIMP3, implicated in extracellular matrix maintenance and also known to interact with LRP1. Our findings support allele-specific LRP1 gene repression by the endothelial-to-mesenchymal transition regulator SNAIL. We propose decreased LRP1 expression in smooth muscle cells to remodel the extracellular matrix enhanced by TGF-β as a potential mechanism of this pleiotropic locus for vascular diseases.

Inducing novel endosymbioses by implanting bacteria in fungi.

Endosymbioses have profoundly impacted the evolution of life and continue to shape the ecology of a wide range of species. They give rise to new combinations of biochemical capabilities that promote innovation and diversification1,2. Despite the many examples of known endosymbioses across the tree of life, their de novo emergence is rare and challenging to uncover in retrospect3-5. Here we implant bacteria into the filamentous fungus Rhizopus microsporus to follow the fate of artificially induced endosymbioses. Whereas Escherichia coli implanted into the cytosol induced septum formation, effectively halting endosymbiogenesis, Mycetohabitans rhizoxinica was transmitted vertically to the progeny at a low frequency. Continuous positive selection on endosymbiosis mitigated initial fitness constraints by several orders of magnitude upon adaptive evolution. Phenotypic changes were underscored by the accumulation of mutations in the host as the system stabilized. The bacterium produced rhizoxin congeners in its new host, demonstrating the transfer of a metabolic function through induced endosymbiosis. Single-cell implantation thus provides a powerful experimental approach to study critical events at the onset of endosymbiogenesis and opens opportunities for synthetic approaches towards designing endosymbioses with desired traits.