Small Extracellular Vesicles Released from Glioma Cells Under Hypoxic Conditions Induce Pericyte-phenotype Transition of Glioma Stem Cells.

Background:The prognosis of malignant glioblastoma (GBM) is dismal despite advances in surgery, radiation and chemotherapy treatments. Thus, alternative therapy strategies are urgently needed. Antiangiogenic therapy for cancer offers the possibility of universal efficacy. However, preclinical and clinical studies suggest that this therapy using anti-VEGF drug Avastin (Bevacizumab) may lead to a pro-migratory phenotype in therapy resistant GBM and thus actively promote tumor invasion and recurrent tumor growth. Methods: An ultracentrifugation strategy was used to isolate glioma-derived sEVs under hypoxic or normoxic conditions. Transmission electron microscopy (TEM), Western blotting, and nanoparticle tracking analysis (NTA) were used to characterize these isolated particles. Cytochalasin D was added to disrupt cellular sEVs uptake. A tube formation assay was used to evaluate angiogenic activity, while ELISAs and Western blotting were used to assess the activated TGF-β signaling pathway. The effects of sEVs on glioma stem cells (GSCs) in vivo were evaluated using subcutaneous xenografts model system in nude mice. Immunofluorescence and immunohistochemical staining were set out to evaluate the pericyte-phenotype transition of GSCs.Results: In this present study, we showed that hypoxia could promote the release of sEVs by glioblastoma cells and hypoxia-induced glioma-derived sEVs could be taken up by GSCs. This internalization of sEVs promoted tumor growth in mouse Xenografts through the pericyte-phenotype transition of GSCs. We also demonstrated hypoxia-derived sEVs can efficiently deliver TGF-β1 to GSCs. The activated TGF-β signaling pathway mediated this kind of phenotype transition. In addition, combination of Ibrutinib and Bevacizumab showed more effective in targeting GBM. Conclusion: This present study provides a new interpretation to the failure of antiangiogenesis therapy in noncurative surgical resection of GBM, and discovers promising brain-specific therapeutic targets for this damaging tumor.

Small Extracellular Vesicles Released from Glioma Cells Under Hypoxic Conditions Induce Pericyte-Phenotype Transition of Glioma Stem Cells.

BackgroundThe prognosis of malignant glioblastoma (GBM) is dismal despite advances in surgery, radiation and chemotherapy treatments. Thus, alternative therapy strategies are urgently needed. Antiangiogenic therapy for cancer offers the possibility of universal efficacy. However, preclinical and clinical studies suggest that this therapy using anti-VEGF drug Avastin (Bevacizumab) may lead to a pro-migratory phenotype in therapy resistant GBM and thus actively promote tumor invasion and recurrent tumor growth. MethodsAn ultracentrifugation strategy was used to isolate glioma-derived sEVs under hypoxic or normoxic conditions. Transmission electron microscopy (TEM), Western blotting, and nanoparticle tracking analysis (NTA) were used to characterize these isolated particles. Cytochalasin D was added to disrupt cellular sEVs uptake. A tube formation assay was used to evaluate angiogenic activity, while ELISAs and Western blotting were used to assess the activated TGF-β signaling pathway. The effects of sEVs on glioma stem cells (GSCs) in vivo were evaluated using subcutaneous xenografts model system in nude mice. Immunofluorescence and immunohistochemical staining were set out to evaluate the pericyte-phenotype transition of GSCs.ResultsIn this present study, we showed that hypoxia could promote the release of sEVs by glioblastoma cells and hypoxia-induced glioma-derived sEVs could be taken up by GSCs. This internalization of sEVs promoted tumor growth in mouse Xenografts through the pericyte-phenotype transition of GSCs. We also demonstrated hypoxia-derived sEVs can efficiently deliver TGF-β1 to GSCs. The activated TGF-β signaling pathway mediated this kind of phenotype transition. In addition, combination of Ibrutinib and Bevacizumab showed more effective in targeting GBM. ConclusionsThis present study provides a new interpretation to the failure of antiangiogenesis therapy in noncurative surgical resection of GBM, and discovers promising brain-specific therapeutic targets for this damaging tumor.

Mechanical and Physical Regulation of Fibroblast–Myofibroblast Transition: From Cellular Mechanoresponse to Tissue Pathology

Fibroblasts are cells present throughout the human body that are primarily responsible for the production and maintenance of the extracellular matrix (ECM) within the tissues. They have the capability to modify the mechanical properties of the ECM within the tissue and transition into myofibroblasts, a cell type that is associated with the development of fibrotic tissue through an acute increase of cell density and protein deposition. This transition from fibroblast to myofibroblast—a well-known cellular hallmark of the pathological state of tissues—and the environmental stimuli that can induce this transition have received a lot of attention, for example in the contexts of asthma and cardiac fibrosis. Recent efforts in understanding how cells sense their physical environment at the micro- and nano-scales have ushered in a new appreciation that the substrates on which the cells adhere provide not only passive influence, but also active stimulus that can affect fibroblast activation. These studies suggest that mechanical interactions at the cell–substrate interface play a key role in regulating this phenotype transition by changing the mechanical and morphological properties of the cells. Here, we briefly summarize the reported chemical and physical cues regulating fibroblast phenotype. We then argue that a better understanding of how cells mechanically interact with the substrate (mechanosensing) and how this influences cell behaviors (mechanotransduction) using well-defined platforms that decouple the physical stimuli from the chemical ones can provide a powerful tool to control the balance between physiological tissue regeneration and pathological fibrotic response.

Reversal of Endothelial Extracellular Vesicle-Induced Smooth Muscle Phenotype Transition by Hypercholesterolemia Stimulation: Role of NLRP3 Inflammasome Activation

Recent studies reported that vascular endothelial cells (ECs) secrete NLR family pyrin domain-containing 3 (NLRP3) inflammasome products such as interleukin-1β (IL-1β) via extracellular vesicles (EVs) under various pathological conditions. EVs represent one of the critical mechanisms mediating the cell-to-cell communication between ECs and vascular smooth muscle cells (VSMCs). However, whether or not the inflammasome-dependent EVs directly participate in the regulation of VSMC function remains unknown. In the present study, we found that in cultured carotid ECs, atherogenic stimulation by oxysterol 7-ketocholesterol (7-Ket) induced NLRP3 inflammasome formation and activation, reduced lysosome-multivesicular bodies (MVBs) fusion, and increased secretion of EVs that contain inflammasome product IL-1β. These EC-derived IL-1β-containing EVs promoted synthetic phenotype transition of co-cultured VSMCs, whereas EVs from unstimulated ECs have the opposite effects. Moreover, acid ceramidase (AC) deficiency or lysosome inhibition further exaggerated the 7-Ket-induced release of IL-1β-containing EVs in ECs. Using a Western diet (WD)-induced hypercholesterolemia mouse model, we found that endothelial-specific AC gene knockout mice (Asah1fl/fl/ECCre) exhibited augmented WD-induced EV secretion with IL-1β and more significantly decreased the interaction of MVBs with lysosomes in the carotid arterial wall compared to their wild-type littermates (WT/WT). The endothelial AC deficiency in Asah1fl/fl/ECCre mice also resulted in enhanced VSMC phenotype transition and accelerated neointima formation. Together, these results suggest that NLRP3 inflammasome-dependent IL-1β production during hypercholesterolemia promotes VSMC phenotype transition to synthetic status via EV machinery, which is controlled by lysosomal AC activity. Our findings provide novel mechanistic insights into understanding the pathogenic role of endothelial NLRP3 inflammasome in vascular injury through EV-mediated EC-to-VSMC regulation.

Single-cell RNA Sequencing: In-depth Decoding of Heart Biology and Cardiovascular Diseases

Background: The cardiac system is a combination of a complex structure, various cells, and versatile specified functions and sophisticated regulatory mechanisms. Moreover, cardiac diseases that encompass a wide range of endogenous conditions, remain a serious health burden worldwide. Recent genome-wide profiling techniques have taken the lead in uncovering a new realm of cell types and molecular programs driving physiological and pathological processes in various organs and diseases. In particular, the emerging technique single-cell RNA sequencing dominates a breakthrough in decoding the cell heterogeneity, phenotype transition, and developmental dynamics in cardiovascular science. Conclusion: Herein, we review recent advances in single cellular studies of cardiovascular system and summarize new insights provided by single-cell RNA sequencing in heart developmental sciences, stem-cell researches as well as normal or disease-related working mechanisms.

Accurate classification of secondary progression in multiple sclerosis using a decision tree

Background: The absence of reliable imaging or biological markers of phenotype transition in multiple sclerosis (MS) makes assignment of current phenotype status difficult. Objective: The authors sought to determine whether clinical information can be used to accurately assign current disease phenotypes. Methods: Data from the clinical visits of 14,387 MS patients in Sweden were collected. Classifying algorithms based on several demographic and clinical factors were examined. Results obtained from the best classifier when predicting neurologist recorded disease classification were replicated in an independent cohort from British Columbia and were compared to a previously published algorithm and clinical judgment of three neurologists. Results: A decision tree (the classifier) containing only most recently available expanded disability scale status score and age obtained 89.3% (95% confidence intervals (CIs): 88.8–89.8) classification accuracy, defined as concordance with the latest reported status. Validation in the independent cohort resulted in 82.0% (95% CI: 81.0–83.1) accuracy. A previously published classification algorithm with slight modifications achieved 77.8% (95% CI: 77.1–78.4) accuracy. With complete patient history of 100 patients, three neurologists obtained 84.3% accuracy compared with 85% for the classifier using the same data. Conclusion: The classifier can be used to standardize definitions of disease phenotype across different cohorts. Clinically, this model could assist neurologists by providing additional information.

ICAT acts as a Coactivator in Regulating PPARγ Transcriptional Activity in Mesangial Cells

Aims Our study aims to explore the role of β-catenin interaction protein-1(ICAT) in regulating peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activity in mesangial cells. The abnormal ICAT expression in mesangial cells under high glucose(HG) contributes to the development of diabetes and its complications such as diabetic nephropathy (DN). Methods Human mesangial cells (HMCs) were cultured in either 5.5 (normal control) or 30 (high glucose) mmol/L glucose medium. Overexpression and knock-down of ICAT or β-catenin were carried out by transient transfection. PPARγ transcriptional activity was evaluated by luciferase assay. Protein-protein interactions were tested by Coimmunoprecipitation and GST-pull down assay. Cell phenotype transition of HMCs was detected by the expression level of α-SMA and fibronectin, as well as MTT assay. Results High β-catenin protein expression but low ICAT was accompanied by low PPARγ transcriptional activity in HMCs cultured in HG. By using bioinformatics prediction, protein-protein and protein-DNA interaction experimental methods, ICAT and β-catenin were confirmed to act as coactivators in regulating PPARγ transcriptional activity. Overexpression of ICAT could mitigate the decrease of PPARγ transcriptional activity and partly relieve cell phenotype transition in HMCs. Conclusions β-catenin and ICAT interact as coactivator to modulate PPARγ transcriptional activation. In HMCs cultured in HG, the low expression of ICAT leads to low PPARγ transcriptional activation.