Endothelial-to-Mesenchymal Transition

Ciliary neurotrophic factor promotes the development of homocysteine-induced vascular endothelial injury through inflammation mediated by the JAK2/STAT3 signaling pathway

Elevated homocysteine (Hcy) levels have been recognized as significant risk factor for cardiovascular and cerebrovascular diseases, closely related to endothelial injury. While expression of Ciliary Neurotrophic Factor (CNTF) significantly increases during Hcy-induced vascular endothelial cell injury, the precise molecular pathways through which CNTF operates remain to be clarified. To induce vascular endothelial cell injury, human umbilical vein endothelial cells (HUVECs) were treated with Hcy. Cell viability and apoptosis in HUVECs were assessed using the CCK-8 assay and flow cytometry. Western blot analysis determined the expression levels of the JAK2-STAT3 pathway, inflammation-related factors (IL-1β, NLRP3, ICAM-1, VCAM-1), and apoptosis-related factors (cleaved Caspase-3 and Bax). Immunofluorescence staining and western blotting were employed to examine CD31 and α-SMA expression. Knockdown of CNTF was achieved using lentiviral interference, and its effects on inflammation and cell injury were evaluated. Chromatin immunoprecipitation (ChIP) and dual luciferase reporter analysis were conducted to investigate the interaction between the MAFK and CNTF promoters. Our results indicated that Hcy induced high expression of CNTF and activated the JAK2-STAT3 signaling pathway, thereby upregulating factors associated with inflammation and cell apoptosis. Inhibiting CNTF alleviated Hcy-induced inflammation and cell injury. MAFK was identified as a transcription factor promoting CNTF transcription, and its overexpression exacerbated inflammation and cell injury in Hcy-treated HUVECs through the CNTF-JAK2-STAT3 axis, which could be reversed by knocking down CNTF. Activation of MAFK leads to CNTF upregulation, which activates the JAK2-STAT3 signaling pathway, regulating inflammation and inducing injury in Hcy-exposed vascular endothelial cells. Targeting CNTF or its upstream regulator MAFK may represent potential therapeutic strategies for mitigating endothelial dysfunction associated with hyperhomocysteinemia and cardiovascular diseases.

Analysis of the heterogeneity and complexity of murine extraorbital lacrimal gland via single-cell RNA sequencing

PURPOSE

The lacrimal gland is essential for maintaining ocular surface health and avoiding external damage by secreting an aqueous layer of the tear film. However, a healthy lacrimal gland's inventory of cell types and heterogeneity remains understudied.

METHODS

Here, 10X Genome-based single-cell RNA sequencing was used to generate an unbiased classification of cellular diversity in the extraorbital lacrimal gland (ELG) of C57BL/6J mice. From 43,850 high-quality cells, we produced an atlas of cell heterogeneity and defined cell types using classic marker genes. The possible functions of these cells were analyzed through bioinformatics analysis. Additionally, the CellChat was employed for a preliminary analysis of the cell-cell communication network in the ELG.

RESULTS

Over 37 subclasses of cells were identified, including seven types of glandular epithelial cells, three types of fibroblasts, ten types of myeloid-derived immune cells, at least eleven types of lymphoid-derived immune cells, and five types of vascular-associated cell subsets. The cell-cell communication network analysis revealed that fibroblasts and immune cells play a pivotal role in the dense intercellular communication network within the mouse ELG.

CONCLUSIONS

This study provides a comprehensive transcriptome atlas and related database of the mouse ELG.

Post-treatment with Resolvin D1 attenuates pulmonary hypertension by inhibiting endothelial-to-mesenchymal transition

Pulmonary hypertension (PH) is a life-threatening disease characterized by pulmonary vascular remodeling. Endothelial-to-mesenchymal transition (EndMT) is an important manifestation and mechanism of pulmonary vascular remodeling. Resolvin D1 (RvD1) is an endogenous lipid mediator promoting the resolution of inflammation. However, the role of RvD1 on EndMT in PH remains unknown. Here, we aimed to investigate the effect and mechanisms of RvD1 on the treatment of PH. We showed that RvD1 and its receptor FPR2 expression were markedly decreased in PH patients and both chronic hypoxia-induced PH (CH-PH) and sugen 5416/hypoxia-induced PH (SuHx-PH) mice models. RvD1 treatment decreased right ventricular systolic pressure (RVSP) and alleviated right ventricular function, and reduced pulmonary vascular remodeling and collagen deposition in the perivascular of both two PH mice models. Then, RvD1 inhibited EndMT in both the lungs of PH mice models and primary cultured human umbilical vein endothelial cells (HUVECs) treated with TGF-β and IL-1β. Moreover, RvD1 inhibited EndMT by downregulating Smad2/3 phosphorylation in vivo and in vitro via FPR2. In conclusion, our date suggest that RvD1/FPR2 axis prevent experimental PH by inhibiting endothelial-mensenchymal-transition and may be a therapeutic target for PH.

New insights into the roles of Irisin in diabetic cardiomyopathy and vascular diseases

Diabetes mellitus (DM) is a prevalent chronic disease in the 21st century due to increased lifespan and unhealthy lifestyle choices. Extensive research indicates that exercise can play a significant role in regulating systemic metabolism by improving energy metabolism and mitigating various metabolic disorders, including DM. Irisin, a well-known exerkine, was initially reported to enhance energy expenditure by indicating the browning of white adipose tissue (WAT) through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) signaling. In this review, we summarize the potential mechanisms underlying the beneficial effects of Irisin on glucose dysmetabolism, including reducing gluconeogenesis, enhancing insulin energy expenditure, and promoting glycogenesis. Additionally, we highlight Irisin's potential to improve diabetic vascular diseases by stimulating nitric oxide (NO) production, reducing oxidative and nitrosative stress, curbing inflammation, and attenuating endothelial cell aging. Furthermore, we discuss the potential of Irisin to improve diabetic cardiomyopathy by preventing cardiomyocyte loss and reducing myocardial hypertrophy and fibrosis. Given Irisin's promising functions in managing diabetic cardiomyopathy and vascular diseases, targeting Irisin for therapeutic purposes could be a fruitful avenue for future research and clinical interventions.

Furin knockdown inhibited EndMT and abnormal proliferation and migration of endothelial cells

BACKGROUND

In the pathogenesis of atherosclerotic cardiovascular disorders, vascular endothelium is crucial. A critical step in the development of atherosclerosis is endothelial dysfunction. Furin may play a factor in vascular remodeling, inflammatory cell infiltration, regulation of plaque stability, and atherosclerosis by affecting the adhesion and migration of endothelial cells. It is yet unknown, though, how furin contributes to endothelial dysfunction.

METHODS

We stimulated endothelial cells with oxidized modified lipoprotein (ox-LDL). Endothelial-to-mesenchymal transition (EndMT) was found using immunofluorescence (IF) and western blot (WB). Furin expression level and Hippo/YAP signal activation were found using reverse transcription-quantitative PCR (RT-qPCR) and WB, respectively. To achieve the goal of furin knockdown, we transfected siRNA using the RNA transmate reagent. Following furin knockdown, cell proliferation, and migration were assessed by the CCK-8, scratch assay, and transwell gold assay, respectively. WB and IF both picked up on EndMT. WB and RT-qPCR, respectively, were used to find furin's expression level. We chose the important micrornas that can regulate furin and we then confirmed them using RT-qPCR.

RESULTS

EndMT was created by ox-LDL, evidenced by the up-regulation of mesenchymal cell markers and the down-regulation of endothelial cell markers. Furin expression levels in both protein and mRNA were increased, and the Hippo/YAP signaling pathway was turned on. Furin knockdown dramatically reduced the aberrant migration and proliferation of endothelial cells by ox-LDL stimulation. Furin knockdown can also suppress ox-LDL-induced EndMT, up-regulate indicators of endothelial cells, and down-regulate markers of mesenchymal cells. After ox-LDL stimulation and siRNA transfection, furin's expression level was up-regulated and down-regulated.

CONCLUSION

Our study demonstrated that furin knockdown could affect ox-LDL-induced abnormal endothelial cell proliferation, migration, and EndMT. This implies that furin plays an important role in endothelial dysfunction.

An update on chronic complications of diabetes mellitus: from molecular mechanisms to therapeutic strategies with a focus on metabolic memory

Diabetes mellitus, a chronic metabolic disease, often leads to numerous chronic complications, significantly contributing to global morbidity and mortality rates. High glucose levels trigger epigenetic modifications linked to pathophysiological processes like inflammation, immunity, oxidative stress, mitochondrial dysfunction, senescence and various kinds of cell death. Despite glycemic control, transient hyperglycemia can persistently harm organs, tissues, and cells, a latent effect termed "metabolic memory" that contributes to chronic diabetic complications. Understanding metabolic memory's mechanisms could offer a new approach to mitigating these complications. However, key molecules and networks underlying metabolic memory remain incompletely understood. This review traces the history of metabolic memory research, highlights its key features, discusses recent molecules involved in its mechanisms, and summarizes confirmed and potential therapeutic compounds. Additionally, we outline in vitro and in vivo models of metabolic memory. We hope this work will inform future research on metabolic memory's regulatory mechanisms and facilitate the development of effective therapeutic compounds to prevent diabetic complications.

egr3 is a mechanosensitive transcription factor gene required for cardiac valve morphogenesis

Biomechanical forces, and their molecular transducers, including key mechanosensitive transcription factor genes, such as KLF2, are required for cardiac valve morphogenesis. However, klf2 mutants fail to completely recapitulate the valveless phenotype observed under no-flow conditions. Here, we identify the transcription factor EGR3 as a conserved biomechanical force transducer critical for cardiac valve formation. We first show that egr3 null zebrafish display a complete and highly penetrant loss of valve leaflets, leading to severe blood regurgitation. Using tissue-specific loss- and gain-of-function tools, we find that during cardiac valve formation, Egr3 functions cell-autonomously in endothelial cells, and identify one of its effectors, the nuclear receptor Nr4a2b. We further find that mechanical forces up-regulate egr3/EGR3 expression in the developing zebrafish heart and in porcine valvular endothelial cells, as well as during human aortic valve remodeling. Altogether, these findings reveal that EGR3 is necessary to transduce the biomechanical cues required for zebrafish cardiac valve morphogenesis, and potentially for pathological aortic valve remodeling in humans.

Bradykinin attenuates endothelial-mesenchymal transition following cardiac ischemia-reperfusion injury

AIMS

Endothelial-mesenchymal transition (EndMT) is a crucial pathological process contributing to cardiac fibrosis. Bradykinin has been found to protect the heart against fibrosis. Whether bradykinin regulates EndMT has not been determined.

MATERIALS AND METHODS

Rats were subjected to ligation of the left anterior descending coronary artery for 1 h and subsequent reperfusion to induce cardiac ischemia-reperfusion (IR) injury. Bradykinin (0.5 μg/h) was infused by an osmotic pump implanted subcutaneously at the onset of reperfusion. Fourteen days later, the functional, histological, and molecular analyses were performed to investigate the changes in cardiac fibrosis and EndMT. Human coronary artery endothelial cells were utilized to determine the molecular mechanisms in vitro.

RESULTS

Bradykinin treatment improved cardiac function and decreased fibrosis following cardiac IR injury, accompanied by ameliorated EndMT and increased nitric oxide (NO) production. In vitro experiments found that bradykinin mitigated transforming growth factor β1 (TGFβ1)-induced EndMT. Significantly, the bradykinin B2 receptor antagonist or endothelial nitric oxide synthase inhibitor abolished the effects of bradykinin on EndMT inhibition, indicating that the bradykinin B2 receptor and NO might mediate the effects of bradykinin on EndMT inhibition.

CONCLUSION

Bradykinin plays an essential role in the process of cardiac fibrosis. Bradykinin preserves the cellular signature of endothelial cells, preventing them from EndMT following cardiac IR injury, possibly mediated by bradykinin B2 receptor activation and NO production.

Angiogenesis Still Plays a Crucial Role in Human Melanoma Progression

Angiogenesis plays a pivotal role in tumor progression, particularly in melanoma, the deadliest form of skin cancer. This review synthesizes current knowledge on the intricate interplay between angiogenesis and tumor microenvironment (TME) in melanoma progression. Pro-angiogenic factors, including VEGF, PlGF, FGF-2, IL-8, Ang, TGF-β, PDGF, integrins, MMPs, and PAF, modulate angiogenesis and contribute to melanoma metastasis. Additionally, cells within the TME, such as cancer-associated fibroblasts, mast cells, and melanoma-associated macrophages, influence tumor angiogenesis and progression. Anti-angiogenic therapies, while showing promise, face challenges such as drug resistance and tumor-induced activation of alternative angiogenic pathways. Rational combinations of anti-angiogenic agents and immunotherapies are being explored to overcome resistance. Biomarker identification for treatment response remains crucial for personalized therapies. This review highlights the complexity of angiogenesis in melanoma and underscores the need for innovative therapeutic approaches tailored to the dynamic TME.

Mangiferin alleviates diabetic pulmonary fibrosis in mice via inhibiting endothelial-mesenchymal transition through AMPK/FoxO3/SIRT3 axis

Diabetes mellitus results in numerous complications. Diabetic pulmonary fibrosis (DPF), a late pulmonary complication of diabetes, has not attracted as much attention as diabetic nephropathy and cardiomyopathy. Mangiferin (MF) is a natural small molecular compound that exhibits a variety of pharmacological effects including anti-inflammatory, anti-cancer, anti-diabetes, and anti-fibrosis effects. In this study, we investigated whether long-term diabetes shock induces DPF, and explored whether MF had a protective effect against DPF. We first examined the lung tissues and sections of 20 diabetic patients obtained from discarded lung surgical resection specimens and found that pulmonary fibrosis mainly accumulated around the pulmonary vessels, accompanied by significantly enhanced endothelial-mesenchymal transition (EndMT). We established a mouse model of DPF by STZ injections. Ten days after the final STZ injection, the mice were administered MF (20, 60 mg/kg, i.g.) every 3 days for 4 weeks, and kept feeding until 16 weeks and euthanized. We showed that pulmonary fibrotic lesions were developed in the diabetic mice, which began around the pulmonary vessels, while MF administration did not affect long-term blood glucose levels, but dose-dependently alleviated diabetes-induced pulmonary fibrosis. In human umbilical vein endothelial cells (HUVECs), exposure to high glucose (33.3 mM) induced EndMT, which was dose-dependently inhibited by treatment with MF (10, 50 μM). Furthermore, MF treatment promoted SIRT3 expression in high glucose-exposed HUVECs by directly binding to AMPK to enhance the activity of FoxO3, which finally reversed diabetes-induced EndMT. We conclude that MF attenuates DPF by inhibiting EndMT through the AMPK/FoxO3/SIRT3 axis. MF could be a potential candidate for the early prevention and treatment of DPF.

YAP/TAZ Signaling Enhances Angiogenesis of Retinal Microvascular Endothelial Cells in a High-Glucose Environment

PURPOSE

Diabetic retinopathy (DR) is a major cause of irreversible blindness in the working-age population. Neovascularization is an important hallmark of advanced DR. There is evidence that Yes-associated protein (YAP)/transcriptional co-activator with a PDZ binding domain (TAZ) plays an important role in angiogenesis and that its activity is regulated by vascular endothelial growth factor (VEGF). Therefore, the aim of this study was to investigate the effect of YAP/TAZ-VEGF crosstalk on the angiogenic capacity of human retinal microvascular endothelial cells (hRECs) in a high-glucose environment.

METHODS

The expression of YAP and TAZ of hRECs under normal conditions, hypertonic conditions and high glucose were observed. YAP overexpression (OE-YAP), YAP silencing (sh-YAP), VEGF overexpression (OE-VEGF) and VEGF silencing (sh-VEGF) plasmids were constructed. Cell counting kit-8 assay was performed to detect cells proliferation ability, transwell assay to detect cells migration ability, and tube formation assay to detect tube formation ability. The protein expression of YAP, TAZ, VEGF, matrix metalloproteinase (MMP)-8, MMP-13, vessel endothelium (VE)-cadherin and alpha smooth muscle actin (α-SMA) was measured by western blot.

RESULTS

The proliferation of hRECs was significantly higher in the high glucose group compared with the normal group, as well as the protein expression of YAP and TAZ (p < 0.01). YAP and VEGF promoted the proliferation, migration and tube formation of hRECs in the high glucose environment (p < 0.01), and increased the expression of TAZ, VEGF, MMP-8, MMP-13 and α-SMA while reducing the expression of VE-cadherin (p < 0.01). Knockdown of YAP effectively reversed the above promoting effects of OE-VEGF (p < 0.01) and overexpression of YAP significantly reversed the inhibition effects of sh-VEGF on above cell function (p < 0.01).

CONCLUSION

In a high-glucose environment, YAP/TAZ can significantly promote the proliferation, migration and tube formation ability of hRECs, and the mechanism may be related to the regulation of VEGF expression.

Directed Differentiation of Human Induced Pluripotent Stem Cells to Heart Valve Cells

BACKGROUND

A main obstacle in current valvular heart disease research is the lack of high-quality homogeneous functional heart valve cells. Human induced pluripotent stem cells (hiPSCs)-derived heart valve cells may help with this dilemma. However, there are no well-established protocols to induce hiPSCs to differentiate into functional heart valve cells, and the networks that mediate the differentiation have not been fully elucidated.

METHODS

To generate heart valve cells from hiPSCs, we sequentially activated the Wnt, BMP4, VEGF (vascular endothelial growth factor), and NFATc1 signaling pathways using CHIR-99021, BMP4, VEGF-165, and forskolin, respectively. The transcriptional and functional similarity of hiPSC-derived heart valve cells compared with primary heart valve cells were characterized. Longitudinal single-cell RNA sequencing was used to uncover the trajectory, switch genes, pathways, and transcription factors of the differentiation.

RESULTS

An efficient protocol was developed to induce hiPSCs to differentiate into functional hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells. After 6-day differentiation and CD144 magnetic bead sorting, ≈70% CD144+ cells and 30% CD144- cells were obtained. On the basis of single-cell RNA sequencing data, the CD144+ cells and CD144- cells were found to be highly similar to primary heart valve endothelial cells and primary heart valve interstitial cells in gene expression profile. Furthermore, CD144+ cells had the typical function of primary heart valve endothelial cells, including tube formation, uptake of low-density lipoprotein, generation of endothelial nitric oxide synthase, and response to shear stress. Meanwhile, CD144- cells could secret collagen and matrix metalloproteinases, and differentiate into osteogenic or adipogenic lineages like primary heart valve interstitial cells. Therefore, we identified CD144+ cells and CD144- cells as hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells, respectively. Using single-cell RNA sequencing analysis, we demonstrated that the trajectory of heart valve cell differentiation was consistent with embryonic valve development. We identified the main switch genes (NOTCH1, HEY1, and MEF2C), signaling pathways (TGF-β, Wnt, and NOTCH), and transcription factors (MSX1, SP5, and MECOM) that mediated the differentiation. Finally, we found that hiPSC-derived valve interstitial-like cells might derive from hiPSC-derived valve endothelial-like cells undergoing endocardial-mesenchymal transition.

CONCLUSIONS

In summary, this is the first study to report an efficient strategy to generate functional hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells from hiPSCs, as well as to elucidate the differentiation trajectory and transcriptional dynamics of hiPSCs differentiated into heart valve cells.

Multiscale computational modeling of aortic valve calcification

Calcific aortic valve disease (CAVD) is a common cardiovascular disease that affects millions of people worldwide. The disease is characterized by the formation of calcium nodules on the aortic valve leaflets, which can lead to stenosis and heart failure if left untreated. The pathogenesis of CAVD is still not well understood, but involves several signaling pathways, including the transforming growth factor beta (TGF β ) pathway. In this study, we developed a multiscale computational model for TGF β -stimulated CAVD. The model framework comprises cellular behavior dynamics, subcellular signaling pathways, and tissue-level diffusion fields of pertinent chemical species, where information is shared among different scales. Processes such as endothelial to mesenchymal transition (EndMT), fibrosis, and calcification are incorporated. The results indicate that the majority of myofibroblasts and osteoblast-like cells ultimately die due to lack of nutrients as they become trapped in areas with higher levels of fibrosis or calcification, and they subsequently act as sources for calcium nodules, which contribute to a polydispersed nodule size distribution. Additionally, fibrosis and calcification processes occur more frequently in regions closer to the endothelial layer where the cell activity is higher. Our results provide insights into the mechanisms of CAVD and TGF β signaling and could aid in the development of novel therapeutic approaches for CAVD and other related diseases such as cancer. More broadly, this type of modeling framework can pave the way for unraveling the complexity of biological systems by incorporating several signaling pathways in subcellular models to simulate tissue remodeling in diseases involving cellular mechanobiology.

Construction of tissue-engineered vascular grafts with enhanced patency by integrating heparin, cell-adhesive peptide, and carbon monoxide nanogenerators into acellular blood vessels

Small-diameter tissue-engineered vascular grafts (sdTEVGs) have garnered significant attention as a potential treatment modality for vascular bypass grafting and replacement therapy. However, the intimal hyperplasia and thrombosis are two major complications that impair graft patency during transplantation. To address this issue, we fabricated the covalent-organic framework (COF)-based carbon monoxide (CO) nanogenerator-and co-immobilized with LXW-7 peptide and heparin to establish a multifunctional surface on TEVGs constructed from acellular blood vessels for preventing thrombosis and stenosis. The cell-adhesive peptide LXW-7 could capture endothelial-forming cells (EFCs) to promote endothelialization, while the antithrombotic molecule heparin prevented thrombus formation. The reactive oxygen species (ROS)-triggered CO release suppressed the adhesion and activation of macrophages, leading to the reduction of ROS and inflammatory factors. As a result, the endothelial-to-mesenchymal transition (EndMT) triggered by inflammation was restricted, facilitating the maintenance of the homeostasis of the neo-endothelium and preventing pathological remodeling in TEVGs. When transplanted in vivo, these vascular grafts exhibited negligible intimal hyperplasia and remained patent for 3 months. This achievement provided a novel approach for constructing antithrombotic and anti-hyperplastic TEVGs.

Protein Disulfide Isomerase 4 Is an Essential Regulator of Endothelial Function and Survival

Endothelial autophagy plays an important role in the regulation of endothelial function. The inhibition of endothelial autophagy is associated with the reduced expression of protein disulfide isomerase 4 (PDIA-4); however, its role in endothelial cells is not known. Here, we report that endothelial cell-specific loss of PDIA-4 leads to impaired autophagic flux accompanied by loss of endothelial function and apoptosis. Endothelial cell-specific loss of PDIA-4 also induced marked changes in endothelial cell architecture, accompanied by the loss of endothelial markers and the gain of mesenchymal markers consistent with endothelial-to-mesenchymal transition (EndMT). The loss of PDIA-4 activated TGFβ-signaling, and inhibition of TGFβ-signaling suppressed EndMT in PDIA-4-silenced endothelial cells in vitro. Our findings help elucidate the role of PDIA-4 in endothelial autophagy and endothelial function and provide a potential target to modulate endothelial function and/or limit autophagy and EndMT in (patho-)physiological conditions.

Endothelial Reprogramming in Atherosclerosis

Atherosclerosis (AS) is a severe vascular disease that results in millions of cases of mortality each year. The development of atherosclerosis is associated with vascular structural lesions, characterized by the accumulation of immune cells, mesenchymal cells, lipids, and an extracellular matrix at the intimal resulting in the formation of an atheromatous plaque. AS involves complex interactions among various cell types, including macrophages, endothelial cells (ECs), and smooth muscle cells (SMCs). Endothelial dysfunction plays an essential role in the initiation and progression of AS. Endothelial dysfunction can encompass a constellation of various non-adaptive dynamic alterations of biology and function, termed "endothelial reprogramming". This phenomenon involves transitioning from a quiescent, anti-inflammatory state to a pro-inflammatory and proatherogenic state and alterations in endothelial cell identity, such as endothelial to mesenchymal transition (EndMT) and endothelial-to-immune cell-like transition (EndIT). Targeting these processes to restore endothelial balance and prevent cell identity shifts, alongside modulating epigenetic factors, can attenuate atherosclerosis progression. In the present review, we discuss the role of endothelial cells in AS and summarize studies in endothelial reprogramming associated with the pathogenesis of AS.

N-Cadherin Targeted Melanin Nanoparticles Reverse the Endothelial-Mesenchymal Transition in Vascular Endothelial Cells to Potentially Slow the Progression of Atherosclerosis and Cancer

Endothelial-mesenchymal transition (EndoMT) of vascular endothelial cells has recently been considered as a key player in the early progression of a variety of vascular and nonvascular diseases, including atherosclerosis, cancer, and organ fibrosis. However, current strategies attempting to identify pharmacological inhibitors to block the regulatory pathways of EndoMT suffer from poor selectivity, unwanted side effects, and a heterogeneous response from endothelial cells with different origins. Furthermore, EndoMT inhibitors focus on preventing EndoMT, leaving the endothelial cells that have already undergone EndoMT unresolved. Here, we report the design of a simple but powerful nanoparticle system (i.e., N-cadherin targeted melanin nanoparticles) to convert cytokine-activated, mesenchymal-like endothelial cells back to their original endothelial phenotype. We term this process "Reversed EndoMT" (R-EndoMT). R-EndoMT allows the impaired endothelial barriers to recover their quiescence and intactness, with significantly reduced leukocyte and cancer cell adhesion and transmigration, which could potentially stop atheromatous plaque formation and cancer metastasis in the early stages. R-EndoMT is achieved on different endothelial cell types originating from arteries, veins, and capillaries, independent of activating cytokines. We reveal that N-cadherin targeted melanin nanoparticles reverse EndoMT by downregulating an N-cadherin dependent RhoA activation pathway. Overall, this approach offers a different prospect to treat multiple EndoMT-associated diseases by designing nanoparticles to reverse the phenotypical transition of endothelial cells.

Endothelial to mesenchymal transition: at the axis of cardiovascular health and disease

Endothelial cells (ECs) line the luminal surface of blood vessels and play a major role in vascular (patho)-physiology by acting as a barrier, sensing circulating factors and intrinsic/extrinsic signals. ECs have the capacity to undergo endothelial-to-mesenchymal transition (EndMT), a complex differentiation process with key roles both during embryonic development and in adulthood. EndMT can contribute to EC activation and dysfunctional alterations associated with maladaptive tissue responses in human disease. During EndMT, ECs progressively undergo changes leading to expression of mesenchymal markers while repressing EC lineage-specific traits. This phenotypic and functional switch is considered to largely exist in a continuum, being characterized by a gradation of transitioning stages. In this report, we discuss process plasticity and potential reversibility and the hypothesis that different EndMT-derived cell populations may play a different role in disease progression or resolution. In addition, we review advancements in the EndMT field, current technical challenges, as well as therapeutic options and opportunities in the context of cardiovascular biology.

Hyperoxia impairs induced pluripotent stem cell-derived endothelial cells and drives an atherosclerosis-like transcriptional phenotype

Background

Induced pluripotent stem cells (iPSCs) directed to endothelial identity (iPSC-ECs) are emerging as a potent tool for regenerative medicine in vascular disease. However, iPSC-ECs lose expression of key identity markers under standard in vitro conditions, limiting their clinical applications.

Methods

To model physiological in vivo conditions, we examined the bioenergetics, presence of key cell markers, and proliferative and angiogenic capacity in iPSC-ECs at late and early passage under hyperoxic (21%) and physiological (4%) oxygen concentrations.

Results

Physoxia resulted in relative preservation of mitochondrial bioenergetic activity, as well as CD144 expression in late passage iPSC-ECs, but not proliferative capacity or tube formation. Single cell RNA sequencing (scRNA-seq) revealed that late passage hyperoxic iPSC-ECs develop an endothelial-to-mesenchymal phenotype. Comparing scRNA-seq data from iPSC-ECs and from atherosclerotic ECs revealed overlap of their transcriptional phenotypes.

Conclusions

Taken together, our studies demonstrate that physiological 4% oxygen culture conditions were sufficient to improve mitochondrial function in high passage cells, but alone was insufficient to preserve angiogenic capacity. Furthermore, late passage cells under typical conditions take on an endothelial-to-mesenchymal phenotype with similarities to ECs found in atherosclerosis.

GTF2H4 regulates partial EndMT via NF-κB activation through NCOA3 phosphorylation in ischemic diseases

Partial endothelial-to-mesenchymal transition (EndMT) is an intermediate phenotype observed in endothelial cells (ECs) undergoing a transition toward a mesenchymal state to support neovascularization during (patho)physiological angiogenesis. Here, we investigated the occurrence of partial EndMT in ECs under hypoxic/ischemic conditions and identified general transcription factor IIH subunit 4 (GTF2H4) as a positive regulator of this process. In addition, we discovered that GTF2H4 collaborates with its target protein excision repair cross-complementation group 3 (ERCC3) to co-regulate partial EndMT. Furthermore, by using phosphorylation proteomics and site-directed mutagenesis, we demonstrated that GTF2H4 was involved in the phosphorylation of receptor coactivator 3 (NCOA3) at serine 1330, which promoted the interaction between NCOA3 and p65, resulting in the transcriptional activation of NF-κB and the NF-κB/Snail signaling axis during partial EndMT. In vivo experiments confirmed that GTF2H4 significantly promoted partial EndMT and angiogenesis after ischemic injury. Collectively, our findings reveal that targeting GTF2H4 is promising for tissue repair and offers potential opportunities for treating hypoxic/ischemic diseases.

Fluid shear stress induced-endothelial phenotypic transition contributes to cerebral ischemia-reperfusion injury and repair

Long-term ischemia leads to insufficient cerebral microvascular perfusion and dysfunction. Reperfusion restores physiological fluid shear stress (FSS) but leads to serious injury. The mechanism underlying FSS-induced endothelial injury in ischemia-reperfusion injury (IRI) remains poorly understood. In this study, a rat model of middle cerebral artery occlusion was constructed to explore cerebrovascular endothelial function and inflammation in vivo. Additionally, the rat brain microvascular endothelial cells (rBMECs) were exposed to a laminar FSS of 0.5 dyn/cm2 for 6 h and subsequently restored to physiological fluid shear stress level (2 dyn/cm2) for 2 and 12 h, respectively. We found that reperfusion induced endothelial-to-mesenchymal transition (EndMT) in endothelial cells, leading to serious blood-brain barrier dysfunction and endothelial inflammation, accompanied by the nuclear accumulation of Yes-associated protein (YAP). During the later stage of reperfusion, cerebral endothelium was restored to the endothelial phenotype with a distinct change in mesenchymal-to-endothelial transition (MEndT), while YAP was translocated and phosphorylated in the cytoplasm. Knockdown of YAP or inhibition of actin polymerization markedly impaired the EndMT in rBMECs. These findings suggest that ischemia-reperfusion increased intensity of FSS triggered an EndMT process and, thus, led to endothelial inflammation and tissue injury, whereas continuous FSS induced a time-dependent reversal MEndT event contributing to the endothelial repair. This study provides valuable insight for therapeutic strategies targeting IRI.

Hsa_circ_0081065 exacerbates IH-induced EndMT via regulating miR-665/HIF-1α signal axis and HIF-1α nuclear translocation

CircRNAs play an important role in various physiological and pathological biological processes. Despite their widespread involvement, the function of circRNAs in intermittent hypoxia (IH) remain incompletely understood. This study aims to clarify the molecular mechanism of it in IH. Differentially expressed circRNAs were identified by transcriptome sequencing analysis in intermittent hypoxia (IH) model. GO and KEGG enrichment analys were performed on the identified differentially expressed circRNAs. The circular characteristics of hsa_circ_0081065 in human umbilical vein endothelial cells (HUVECs) were detected by RT-qPCR. The sublocalization of hsa_circ_0081065 was examined by FISH. The effect of hsa_circ_0081065 on endothelial to mesenchymal transition (EndMT) was estimated by detecting the expression of EndMT related markers. Various techniques, including RNA-pull down, RIP, EMSA, dual-luciferase reporter assay and immunofluorescence staining were used to investigate the relationship among hsa_circ_0081065, miR-665 and HIF-1α. A total of 13,304 circRNAs were identified in HUVECs treatment with IH, among which 73 were differentially expressed, including 24 upregulated circRNAs and 49 downregulated circRNAs. Notably, hsa_circ_0081065 demonstrated a significantly upregulation. Hsa_circ_0081065 exhibited the circular characteristics of circRNA and was predominantly localized in the cytoplasm. Knockdown of hsa_circ_0081065 inhibited EndMT. Mechanically, we demonstrated that hsa_circ_0081065 acts as a sponge for miR-665 to up-regulate HIF-1α and exacerbate HIF-1α nuclear translocation in HUVECs. We have demonstrated that hsa_circ_0081065 is significantly upregulated in HUVECs treated with IH. Our findings indicate that hsa_circ_0081065 exacerbates IH-induced EndMT through the regulation of the miR-665/HIF-1α signal axis and facilitating HIF-1α nuclear translocation. These results provide a theoretical basis for considering of EndMT as a potential therapeutic target for OSAHS intervention.

Cellular Transdifferentiation: A Crucial Mechanism of Fibrosis in Systemic Sclerosis

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology with a highly complex pathogenesis that despite extensive investigation is not completely understood. The clinical and pathologic manifestations of the disease result from three distinct processes: 1) Severe and frequently progressive tissue fibrosis causing exaggerated and deleterious accumulation of interstitial collagens and other extracellular matrix molecules in the skin and various internal organs; 2) extensive fibroproliferative vascular lesions affecting small arteries and arterioles causing tissue ischemic alterations; and 3) cellular and humoral immunity abnormalities with the production of numerous autoantibodies, some with very high specificity for SSc. The fibrotic process in SSc is one of the main causes of disability and high mortality of the disease. Owing to its essentially universal presence and the severity of its clinical effects, the mechanisms involved in the development and progression of tissue fibrosis have been extensively investigated, however, despite intensive investigation, the precise molecular mechanisms have not been fully elucidated. Several recent studies have suggested that cellular transdifferentiation resulting in the phenotypic conversion of various cell types into activated myofibroblasts may be one important mechanism. Here, we review the potential role that cellular transdifferentiation may play in the development of severe and often progressive tissue fibrosis in SSc.

Coagulation Disorders and Thrombotic Complications in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is associated with multiple cardiovascular and noncardiovascular comorbidities and risk factors which increase the risk of thrombotic complications, such as atrial fibrillation, chronic kidney disease, arterial hypertension and type 2 diabetes mellitus. Subsequently, thromboembolic risk stratification in this population poses a great challenge. Since date from the large randomized clinical trials mostly include both patients with truly preserved EF, and those with heart failure with mildly reduced ejection fraction, there is an unmet need to characterize the patients with truly preserved EF. Considering the significant evidence gap in this area, we sought to describe the coagulation disorders and thrombotic complications in patients with HFpEF and discuss the specific thromboembolic risk factors in patients with HFpEF, with the goal to tailor risk stratification to an individual patient.

Fibroblasts in immune-mediated inflammatory diseases: The soil of inflammation

As one of the most abundant stromal cells, fibroblasts are primarily responsible for the production and remodeling of the extracellular matrix. Traditionally, fibroblasts have been viewed as quiescent cells. However, recent advances in multi-omics technologies have demonstrated that fibroblasts exhibit remarkable functional diversity at the single-cell level. Additionally, fibroblasts are heterogeneous in their origins, tissue locations, and transitions with stromal cells. The dynamic nature of fibroblasts is further underscored by the fact that disease stages can impact their heterogeneity and behavior, particularly in immune-mediated inflammatory diseases such as psoriasis, inflammatory bowel diseases, and rheumatoid arthritis, etc. Fibroblasts can actively contribute to the disease initiation, progression, and relapse by responding to local microenvironmental signals, secreting downstream inflammatory factors, and interacting with immune cells during the pathological process. Here we focus on the development, plasticity, and heterogeneity of fibroblasts in inflammation, emphasizing the need for a developmental and dynamic perspective on fibroblasts.

miR-186 regulates epithelial-mesenchymal transformation to promote nasopharyngeal carcinoma metastasis by targeting ZEB1

OBJECTIVES

Nasopharyngeal carcinoma (NPC) is an aggressive epithelial cancer. The expression of miR-186 is decreased in a variety of malignancies and can promote the invasion and metastasis of cancer cells. This study aimed to explore the role and possible mechanism of miR-186 in the metastasis and epithelial-mesenchymal transformation (EMT) of NPC.

METHODS

The expression of miR-186 in NPC tissues and cells was detected by RT-PCR. Then, miR-186 mimic was used to transfect NPC cell lines C666-1 and CNE-2, and cell activity, invasion and migration were detected by CCK8, transwell and scratch assay, respectively. The expression of EMT-related proteins was analyzed by western blotting analysis. The binding relationship between miR-186 and target gene Zinc Finger E-Box Binding Homeobox 1 (ZEB1) was confirmed by double luciferase assay.

RESULTS

The expression of miR-186 in NPC was significantly decreased, and transfection of miR-186 mimic could significantly inhibit the cell activity, invasion, and migration, and regulate the protein expressions of E-cadherin, N-cadherin and vimentin in C666-1 and CNE-2 cells. Further experiments confirmed that miR-186 could directly target ZEB1 and negatively regulate its expression. In addition, ZEB1 has been confirmed to be highly expressed in NPC, and inhibition of ZEB1 could inhibit the activity, invasion, metastasis and EMT of NPC cells. And co-transfection of miR-186 mimic and si-ZEB1 could further inhibit the proliferation and metastasis of NPC.

CONCLUSION

miR-186 may inhibit the proliferation, metastasis and EMT of NPC by targeting ZEB1, and the miR-186/ZEB1 axis plays an important role in NPC.

Maternal exposure to nano-titanium dioxide impedes fetal development via endothelial-to-mesenchymal transition in the placental labyrinth in mice

BACKGROUND

Extensive production and usage of commercially available products containing TiO2 NPs have led to accumulation in the human body. The deposition of TiO2 NPs has even been detected in the human placenta, which raises concerns regarding fetal health. Previous studies regarding developmental toxicity have frequently focused on TiO2 NPs < 50 nm, whereas the potential adverse effects of large-sized TiO2 NPs received less attention. Placental vasculature is essential for maternal-fetal circulatory exchange and ensuring fetal growth. This study explores the impacts of TiO2 NPs (100 nm in size) on the placenta and fetal development and elucidates the underlying mechanism from the perspective of placental vasculature. Pregnant C57BL/6 mice were exposed to TiO2 NPs by gavage at daily dosages of 10, 50, and 250 mg/kg from gestational day 0.5-16.5.

RESULTS

TiO2 NPs penetrated the placenta and accumulated in the fetal mice. The fetuses in the TiO2 NP-exposed groups exhibited a dose-dependent decrease in body weight and length, as well as in placental weight and diameter. In vivo imaging showed an impaired placental barrier, and pathological examinations revealed a disrupted vascular network of the labyrinth upon TiO2 NP exposure. We also found an increase in gene expression related to the transforming growth factor-β (TGF-β) -SNAIL pathway and the upregulation of mesenchymal markers, accompanied by a reduction in endothelial markers. In addition, TiO2 NPs enhanced the gene expression responsible for the endothelial-to-mesenchymal transition (EndMT) in cultured human umbilical vein endothelial cells, whereas SNAIL knockdown attenuated the induction of EndMT phenotypes.

CONCLUSION

Our study revealed that maternal exposure to 100 nm TiO2 NPs disrupts placental vascular development and fetal mice growth through aberrant activation of EndMT in the placental labyrinth. These data provide novel insight into the mechanisms of developmental toxicity posed by NPs.

Fetoplacental endothelial dysfunction in gestational diabetes mellitus and maternal obesity: A potential threat for programming cardiovascular disease

Gestational diabetes mellitus (GDM) and maternal obesity (MO) increase the risk of adverse fetal outcomes, and the incidence of cardiovascular disease later in life. Extensive research has been conducted to elucidate the underlying mechanisms by which GDM and MO program the offspring to disease. This review focuses on the role of fetoplacental endothelial dysfunction in programming the offspring for cardiovascular disease in GDM and MO pregnancies. We discuss how pre-existing maternal health conditions can lead to vascular dysfunction in the fetoplacental unit and the fetus. We also examine the role of fetoplacental endothelial dysfunction in impairing fetal cardiovascular system development and the involvement of nitric oxide and hydrogen sulfide in mediating fetoplacental vascular dysfunction. Furthermore, we suggest that the L-Arginine-Nitric Oxide and the Adenosine-L-Arginine-Nitric Oxide (ALANO) signaling pathways are pertinent targets for research. Despite significant progress in this area, there are still knowledge gaps that need to be addressed in future research.

High-Salt Diet Aggravates Endothelial-to-Mesenchymal Transition in Glomerular Fibrosis in Dahl Salt-Sensitive Rats

BACKGROUND

Both diabetic and hypertensive nephropathy eventually progress to glomerulosclerosis. Previous studies revealed a potential role of endothelial-to-mesenchymal transition (EndMT) in the pathophysiology of glomerulosclerosis in diabetic rats. Therefore, we hypothesized that EndMT was also involved in the development of glomerulosclerosis in salt-sensitive hypertension. We aimed to explore the effects of high-salt diet on endothelial-to-mesenchymal transition (EndMT) in glomerulosclerosis in Dahl salt-sensitive (Dahl-SS) rats.

METHODS

Eight-week-old male rats were fed high-salt (8%NaCl; DSH group) or normal salt (0.3%NaCl; DSN group) for eight weeks, with systolic blood pressure (SBP), serum creatinine, urea, 24-hour urinary protein/sodium, renal interlobar artery blood flow, and pathological examination measured. We also examined endothelial-(CD31) and fibrosis-related protein(α-SMA) expressions in glomeruli.

RESULTS

High-salt diet increased SBP (DSH vs. DSN, 205.2 ± 8.9 vs. 135.4 ± 7.9 mm Hg, P < 0.01), 24-hour urinary protein (132.55 ± 11.75 vs. 23.52 ± 5.94 mg/day, P < 0.05), urine sodium excretions (14.09 ± 1.49 vs. 0.47 ± 0.06 mmol/day, P < 0.05), and renal interlobar artery resistance. Glomerulosclerosis increased (26.1 ± 4.6 vs. 7.3 ± 1.6%, P < 0.05), glomerular CD31 expressions decreased while α-SMA expression increased in DSH group. Immunofluorescence staining showed that CD31 and α-SMA co-expressed in glomeruli of the DSH group. The degree of glomerulosclerosis negatively correlated with CD31 expressions (r = -0.823, P < 0.01) but positively correlated with α-SMA expressions (r = 0.936, P < 0.01).

CONCLUSIONS

We demonstrated that a high-salt diet led to glomerulosclerosis involving the EndMT process, which played an essential role in glomerulosclerosis in hypertensive Dahl-SS rats.

Non-coding RNA-mediated endothelial-to-mesenchymal transition in human diabetic cardiomyopathy, potential regulation by DNA methylation

AIMS

Diabetic cardiomyopathy (DCM) is a major complication of diabetes and a risk factor for cardiovascular disease. Endothelial dysfunction is central to DCM, and endothelial-to-mesenchymal transition (EndMT) is a key form of endothelial dysfunction in diabetes. EndMT in DCM has been well-studied in model systems and has been found to be epigenetically regulated by non-coding RNAs (ncRNAs). However, EndMT in DCM and its associated epigenetic changes need further characterization in human patients. It is also not known if ncRNAs are affected by changes in DNA methylation in DCM. This study aims to confirm in human hearts, the findings from animal and cell studies, and potentially provide novel insight into interactions between DNA methylation and ncRNAs in EndMT in DCM.

METHODS AND RESULTS

Heart tissues were collected from autopsy patients, fixed in formalin, and embedded in paraffin. Thin sections from paraffin-embedded tissues were used for histology and immunofluorescence analyses, where we confirmed that diabetic patients showed increased cardiac fibrosis that EndMT had occurred. Tissue curls from the paraffin-embedded tissues were used for RT-qPCR and methylation analyses. RT-qPCR quantitatively showed that EndMT occurs in the hearts of diabetics, and that EndMT in human hearts corresponded to changes in key ncRNAs. Methylation analysis showed that some of the EndMT-related ncRNAs were regulated by DNA promoter methylation, while others may be regulated through different epigenetic mechanisms.

CONCLUSIONS

We show that EndMT is a relevant pathological process in human hearts during DCM, and that its occurrence coincides with changes in relevant ncRNAs. We further find that interplay between DNA methylation and certain ncRNAs involved in the regulation of EndMT may contribute to the observed changes in ncRNA expression. These findings reinforce the role of EndMT in patients afflicted with DCM and underscore the complexities and importance of the interactions between different facets of epigenetic regulation.

Endothelial cell dysfunction in cardiac disease: driver or consequence?

The vascular endothelium is a multifunctional cellular system which directly influences blood components and cells within the vessel wall in a given tissue. Importantly, this cellular interface undergoes critical phenotypic changes in response to various biochemical and hemodynamic stimuli, driving several developmental and pathophysiological processes. Multiple studies have indicated a central role of the endothelium in the initiation, progression, and clinical outcomes of cardiac disease. In this review we synthesize the current understanding of endothelial function and dysfunction as mediators of the cardiomyocyte phenotype in the setting of distinct cardiac pathologies; outline existing in vivo and in vitro models where key features of endothelial cell dysfunction can be recapitulated; and discuss future directions for development of endothelium-targeted therapeutics for cardiac diseases with limited existing treatment options.

Nuclear mechanosensing of the aortic endothelium in health and disease

The endothelium, the monolayer of endothelial cells that line blood vessels, is exposed to a number of mechanical forces, including frictional shear flow, pulsatile stretching and changes in stiffness influenced by extracellular matrix composition. These forces are sensed by mechanosensors that facilitate their transduction to drive appropriate adaptation of the endothelium to maintain vascular homeostasis. In the aorta, the unique architecture of the vessel gives rise to changes in the fluid dynamics, which, in turn, shape cellular morphology, nuclear architecture, chromatin dynamics and gene regulation. In this Review, we discuss recent work focusing on how differential mechanical forces exerted on endothelial cells are sensed and transduced to influence their form and function in giving rise to spatial variation to the endothelium of the aorta. We will also discuss recent developments in understanding how nuclear mechanosensing is implicated in diseases of the aorta.

Mechanical stress induced EndoMT in endothelial cells through PPARγ downregulation

Portal hypertension is a group of clinical syndromes induced by increased portal system pressure due to various etiologies including cirrhosis. When portal hypertension develops, the portal vein dilates and endothelial cells (ECs) in the portal vein are subjected to mechanical stretch. In this study, elastic silicone chambers were used to simulate the effects of mechanical stretch on ECs under portal hypertension. We found that mechanical stretch decreased PPARγ expression in ECs by blocking the PI3K/AKT/CREB signaling pathway or increasing NEDD4-mediated ubiquitination and degradation of PPARγ. Moreover, PPARγ downregulation triggered Endothelial-to-mesenchymal transition (EndoMT) in ECs under stretch by promoting Smad3 phosphorylation. The PPARγ agonist rosiglitazone mitigated stretch-induced EndoMT in vitro and alleviated EndoMT of the portal vein endothelium in cirrhotic rats.

Interplay between BMP2 and Notch signaling in endothelial-mesenchymal transition: implications for cardiac fibrosis

Background

The endothelial-to-mesenchymal transition (EndoMT) is a crucial process in cardiovascular development and disorders. Cardiac fibrosis, characterized by excessive collagen deposition, occurs in heart failure, leading to the organ remodeling. Embryonic signaling pathways such as bone morphogenetic protein 2 (BMP2) and Notch are involved in its regulation. However, the interplay between these pathways in EndoMT remains unclear.

Methods

This study investigates the downstream targets of Notch and BMP2 and their effect on EndoMT markers in cardiac mesenchymal cells (CMCs) and human umbilical vein endothelial cells (HUVECs). We transduced cell cultures with vectors carrying intracellular domain of NOTCH1 (NICD) and/or BMP2 and evaluated gene expression and activation of EndoMT markers.

Results

The results suggest that the Notch and BMP2 signaling pathways have common downstream targets that regulate EndoMT. The activation of BMP2 and Notch is highly dependent on cell type, and co-cultivation of CMCs and HUVECs produced opposing cellular responses to target gene expression and α-smooth muscle actin (α-SMA) synthesis.

Conclusions

The balance between Notch and BMP2 signaling determines the outcome of EndoMT and fibrosis in the heart. The study's findings highlight the need for further research to understand the interaction between Notch and BMP2 in the heart and develop new therapeutic strategies for treating cardiac fibrosis.

New insight into the role of fibroblasts in the epithelial immune microenvironment in the single-cell era

The skin is exposed to environmental challenges and contains heterogeneous cell populations such as epithelial cells, stromal cells, and skin-resident immune cells. As the most abundant type of stromal cells, fibroblasts have been historically considered silent observers in the immune responses of the cutaneous epithelial immune microenvironment (EIME), with little research conducted on their heterogeneity and immune-related functions. Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) have overcome the limitations of bulk RNA sequencing and help recognize the functional and spatial heterogeneity of fibroblasts, as well as their crosstalk with other types of cells in the cutaneous EIME. Recently, emerging single-cell sequencing data have demonstrated that fibroblasts notably participate in the immune responses of the EIME and impact the initiation and progression of inflammatory skin diseases. Here, we summarize the latest advances in the role of fibroblasts in the cutaneous EIME of inflammatory skin diseases and discuss the distinct functions and molecular mechanisms of activated fibroblasts in fibrotic skin diseases and non-fibrotic inflammatory skin diseases. This review help unveil the multiple roles of fibroblasts in the cutaneous EIME and offer new promising therapeutic strategies for the management of inflammatory skin diseases by targeting fibroblasts or the fibroblast-centered EIME.

[High expression of CAMSAP2 promotes invasion and metastasis of gastric cancer cells by upregulating TGF-β signaling]

OBJECTIVE

To investigate the expression of calmodulin-regulated spectrin-associated protein 2 (CAMSAP2) in gastric cancer and its effect on gastric cancer cell invasion and metastasis.

METHODS

The association of CAMSAP2 expression levels with progression and prognosis of gastric cancer was analyzed using public cancer data and in 106 patients receiving radical gastrectomy in our hospital from October, 2013 to October, 2017. The biological functions of CAMSAP2 were predicted using bioinformatics analysis. Gastric cancer MGC803 cells with CAMSAP2 overexpression and knockdown were observed for epithelial-mesenchymal transition (EMT), migration and invasion. A nude mouse model bearing orthotopic gastric cancer cell xenografts was established for verifying the results and exploring the underlying molecular mechanism.

RESULTS

Gastric cancer tissues expressed high levels of CAMSAP2, which were positively correlated with CEA and CA19-9 (P<0.001). Cox regression analysis showed that CAMSAP2 expression level was an independent risk factor affecting the 5-year survival rate of gastric cancer patients (HR=2.969, 95% CI: 1.031-8.548). Enrichment analysis suggested that CAMSAP2 was involved in epithelialmesenchymal transition (EMT) and TGF-β signaling. In gastric cancer cells, CAMSAP2 overexpression significantly increased the expressions of vimentin and N-cadherin, inhibited the expression of E-cadherin, and enhanced cell migration and invasion (P<0.05); CAMSAP2 knockdown produced the opposite effects in the cells (P<0.05). In the tumor- bearing mice, xenografts overexpressing CAMSAP2 showed enhanced metastasis (P<0.05), increased vimentin and N-cadherin expressions and lowered E-cadherin expression (P<0.05), and the xenografts with CAMSAP2 knockdown showed the opposite changes (P<0.05). Both the in vivo and in vitro experiments showed that CAMSAP2 overexpression increased and CAMSAP2 knockdown lowered the levels of TGF-β and p-Smad2/3 in the gastric cancer cells (P<0.05).

CONCLUSION

The high expression of CAMSAP2 contributes to disease progression and poor prognosis of gastric cancer possibly by upregulating TGF-β signaling to promote EMT.

PECAM-1 drives β-catenin-mediated EndMT via internalization in colon cancer with diabetes mellitus

BACKGROUND

Diabetes mellitus (DM) is considered to be a risk factor in carcinogenesis and progression, although the biological mechanisms are not well understood. Here we demonstrate that platelet-endothelial cell adhesion molecule 1 (PECAM-1) internalization drives β-catenin-mediated endothelial-mesenchymal transition (EndMT) to link DM to cancer.

METHODS

The tumor microenvironment (TME) was investigated for differences between colon cancer with and without DM by mRNA-microarray analysis. The effect of DM on colon cancer was determined in clinical patients and animal models. Furthermore, EndMT, PECAM-1 and Akt/GSK-3β/β-catenin signaling were analyzed under high glucose (HG) and human colon cancer cell (HCCC) supernatant (SN) or coculture conditions by western and immunofluorescence tests.

RESULTS

DM promoted the progression and EndMT occurrence of colon cancer (CC). Regarding the mechanism, DM induced PECAM-1 defection from the cytomembrane, internalization and subsequent accumulation around the cell nucleus in endothelial cells, which promoted β-catenin entry into the nucleus, leading to EndMT occurrence in CC with DM. Additionally, Akt/GSK-3β signaling was enhanced to inhibit the degradation of β-catenin, which regulates the process of EndMT.

CONCLUSIONS

PECAM-1 defects and/or internalization are key events for β-catenin-mediated EndMT, which is significantly boosted by enhanced Akt/GSK-3β signaling in the DM-associated TME. This contributes to the mechanism by which DM promotes the carcinogenesis and progression of CC. Video Abstract.

The role of vascular endothelial cells in tumor metastasis

Vascular endothelial cells (VECs) are an integral component of the inner lining of blood vessels, and their functions are essential for the proper functioning of the vascular system. The tight junctions formed by VECs act as a significant barrier to the intravasation and extravasation of tumor cells (TCs). In addition to that, the proliferation, activation, and migration of VECs play a vital role in the growth of new blood vessels, a process known as tumor angiogenesis, which is closely related to the malignant progression of tumors. However, during tumor progression, VECs undergo endothelial-to-mesenchymal transition (EndMT), which further promotes tumor progression. Furthermore, VECs act as the first line of defense against effector immune cells and help prevent immune cells from infiltrating into tumor tissues. VECs also secrete various cytokines that can contribute to regulating the stemness of tumor stem cells. Thus, it has been increasingly recognized that dysfunction of VECs is one of the key driving forces behind tumor metastasis, and therapeutic strategies targeting VECs have the potential to be an effective means of antitumor therapy. This review aims to present a comprehensive overview of the role and mechanisms of VECs in regulating tumor progression and metastasis, providing insights into the possibilities for the development of novel antitumor therapies that target VECs.

RBM25 induces trophoblast epithelial-mesenchymal transition and preeclampsia disorder by enhancing the positive feedback loop between Grhl2 and RBM25

Defects in migration and invasion caused by dysregulation of trophoblast epithelial-mesenchymal transformation (EMT) are one of the key factors in the pathogenesis of preeclampsia (PE). RNA-binding motif protein 25 (RBM25) is an RNA-binding protein involved in a variety of cellular processes, including cell proliferation, apoptosis, cell migration and invasion, and EMT. However, the expression and function of RBM25 in placental of PE remain unclear. In this study, we reveal that the expression of RBM25 is significantly elevated in PE placental tissue. RBM25 depletion and over-expression in trophoblast cells increase and decrease, respectively, cell migration and invasion by regulating EMT marker E-cadherin and Vimentin expression. Mechanistically, Grhl2 is involved in RBM25-regulated trophoblast cell migration, invasion, and EMT through RBM25-facilitated mRNA stabilization. Furthermore, the upregulation of Grhl2 enhances the expression of RBM25 through transcription and forms a positive feedback regulation in the progression of PE. These findings suggest that upregulation of RBM25 induces dysregulation of trophoblast EMT by enhancing positive feedback regulation of Grhl2 and RBM25, leading to defects in cell migration and invasion. Targeting this newly identified regulatory axis may provide benefits in the prevention and treatment of PE.

Endothelial-to-mesenchymal transition: New insights into vascular calcification

With the continuous progress of atherosclerosis research, the significant pathological change of it--vascular calcification (VC), gains increasing attention. In recent years, numerous studies have demonstrated that it is an independent predictor of death risk of cardiovascular disease, and it has a strong correlation with poor clinical prognosis. As the world's population continues to age, the occurrence of VC is expected to reach its highest point in the near future. Therefore, it is essential to investigate ways to prevent or even reverse this process for clinical purposes. Endothelial-to-mesenchymal transition (EndMT) describes the progressive differentiation of endothelial cells into mesenchymal stem cells (MSCs) under various stimuli and acquisition of pluripotent cell characteristics. More and more studies show that EndMT plays a vital role in various cardiovascular diseases, including atherosclerosis, vascular calcification and heart valvular disease. EndMT is also involved in the formation and progression of VC. This review vividly describes the history, characteristics of EndMT and how it affects the endothelial cell process, then focuses on the relationship between vascular endothelium, EndMT, amino acid metabolism, and vascular calcification. Finally, it overviews the signal pathway of EndMT and drugs targeting EndMT, hoping to provide new ideas and a theoretical basis for studying potential therapeutic targets of VC.

Network pharmacology combined with molecular docking and experimental validation to reveal the pharmacological mechanism of naringin against renal fibrosis

To explore the pharmacological mechanism of naringin (NRG) in renal fibrosis (RF) based on network pharmacology combined with molecular docking and experimental validation. We used databases to screen for the targets of NRG and RF. The "drug-disease network" was established using Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of targets were performed using Metascape, and molecular docking was performed using Schrödinger. We established an RF model in both mice and cells to validate the results of network pharmacology. After screening the database, we identified 222 common targets of NRG and RF and established a target network. Molecular docking showed that the target AKT had a good interaction with NRG. We found that the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway was enriched by multiple targets and served as a target for experimental validation through GO and KEGG. The results revealed that NRG ameliorated renal dysfunction, reduced the release of inflammatory cytokines, decreased the expression of α-SMA, collagen I, and Fn, and recovered the expression of E-cad by inhibiting the PI3K/AKT signaling pathway. Our study used pharmacological analysis to predict the targets and mechanisms of NRG against RF. Furthermore, experiments proved that NRG inhibited RF effectively by targeting the PI3K/AKT signaling pathway.

Fibroblasts-Warriors at the Intersection of Wound Healing and Disrepair

Wound healing is triggered by inflammation elicited after tissue injury. Mesenchymal cells, specifically fibroblasts, accumulate in the injured tissues, where they engage in tissue repair through the expression and assembly of extracellular matrices that provide a scaffold for cell adhesion, the re-epithelialization of tissues, the production of soluble bioactive mediators that promote cellular recruitment and differentiation, and the regulation of immune responses. If appropriately deployed, these processes promote adaptive repair, resulting in the preservation of the tissue structure and function. Conversely, the dysregulation of these processes leads to maladaptive repair or disrepair, which causes tissue destruction and a loss of organ function. Thus, fibroblasts not only serve as structural cells that maintain tissue integrity, but are key effector cells in the process of wound healing. The review will discuss the general concepts about the origins and heterogeneity of this cell population and highlight the specific fibroblast functions disrupted in human disease. Finally, the review will explore the role of fibroblasts in tissue disrepair, with special attention to the lung, the role of aging, and how alterations in the fibroblast phenotype underpin disorders characterized by pulmonary fibrosis.

Antisense Oligonucleotides against Let-7 Enhance the Therapeutic Potential of Mesenchymal Stromal Cells

Let-7 miRNAs have pleiotropic cellular functions in cell proliferation, migration, and regenerative processes. Here, we investigate whether the inhibition of let-7 miRNAs with antisense oligonucleotides (ASOs) can be a transient and safe strategy enhancing the therapeutic potential of mesenchymal stromal cells (MSCs) to overcome their limitations in cell therapeutic trials. We first identified major subfamilies of let-7 miRNAs preferentially expressed in MSCs, and efficient ASO combinations against these selected subfamilies that mimic the effects of LIN28 activation. When let-7 miRNAs were inhibited with an ASO combination (anti-let7-ASOs), MSCs exhibited higher proliferation with delayed senescence during the passaging into a culture. They also exhibited increased migration and enhanced osteogenic differentiation potential. However, these changes in MSCs were not accompanied by cell-fate changes into pericytes or the additional acquisition of stemness, but instead occurred as functional changes accompanied by changes in proteomics. Interestingly, MSCs with let-7 inhibition exhibited metabolic reprogramming characterized by an enhanced glycolytic pathway, decreased reactive oxygen species, and lower transmembrane potential in mitochondria. Moreover, let-7-inhibited MSCs promoted the self-renewal of neighboring hematopoietic progenitor cells, and enhanced capillary formation in endothelial cells. These findings together show that our optimized ASO combination efficiently reprograms the MSC functional state, allowing for more efficient MSC cell therapy.

MIR503HG: A potential diagnostic and therapeutic target in human diseases

LncRNAs are involved in many physiological and pathological processes, including chromatin remodeling, transcription, posttranscriptional gene expression, mRNA stability, translation, and posttranslational modification, and their functions depend on subcellular localization. MIR503HG is a lncRNA as well as a host gene for the miRNAs miR-503 and miR-424. MIR503HG functions independently or synergistically with miR-503. MIR503HG affects cell proliferation, invasion, metastasis, apoptosis, angiogenesis, and other biological behaviors. The mechanism of MIR503HG in disease includes interaction with protein, sponging miRNA to regulate downstream target gene, and participation in NF-κB, TGF-β, ERK/MAPK, and PI3K/AKT signaling pathways. In this review, we summarize the molecular mechanisms of MIR503HG in disease and its potential applications in diagnosis, prognosis, and treatment. We also raise some unanswered questions in this area, providing insights for future research.

Unleashing the potential of combining FGFR inhibitor and immune checkpoint blockade for FGF/FGFR signaling in tumor microenvironment

BACKGROUND

Fibroblast growth factors (FGFs) and their receptors (FGFRs) play a crucial role in cell fate and angiogenesis, with dysregulation of the signaling axis driving tumorigenesis. Therefore, many studies have targeted FGF/FGFR signaling for cancer therapy and several FGFR inhibitors have promising results in different tumors but treatment efficiency may still be improved. The clinical use of immune checkpoint blockade (ICB) has resulted in sustained remission for patients. MAIN: Although there is limited data linking FGFR inhibitors and immunotherapy, preclinical research suggest that FGF/FGFR signaling is involved in regulating the tumor microenvironment (TME) including immune cells, vasculogenesis, and epithelial-mesenchymal transition (EMT). This raises the possibility that ICB in combination with FGFR-tyrosine kinase inhibitors (FGFR-TKIs) may be feasible for treatment option for patients with dysregulated FGF/FGFR signaling.

CONCLUSION

Here, we review the role of FGF/FGFR signaling in TME regulation and the potential mechanisms of FGFR-TKI in combination with ICB. In addition, we review clinical data surrounding ICB alone or in combination with FGFR-TKI for the treatment of FGFR-dysregulated tumors, highlighting that FGFR inhibitors may sensitize the response to ICB by impacting various stages of the "cancer-immune cycle".

Mouse endothelial OTUD1 promotes angiotensin II-induced vascular remodeling by deubiquitinating SMAD3

Understanding the molecular mechanisms of pathological vascular remodeling is important for treating cardiovascular diseases and complications. Recent studies have highlighted a role of deubiquitinases in vascular pathophysiology. Here, we investigate the role of a deubiquitinase, OTUD1, in angiotensin II (Ang II)-induced vascular remodeling. We detect upregulated OTUD1 in the vascular endothelium of Ang II-challenged mice and show that OTUD1 deletion attenuates vascular remodeling, collagen deposition, and EndMT. Conversely, OTUD1 overexpression aggravates these pathological changes both in vivo and in vitro. Mechanistically, SMAD3 is identified as a substrate of OTUD1 using co-immunoprecipitation followed by LC-MS/MS. We find that OTUD1 stabilizes SMAD3 and facilitates SMAD3/SMAD4 complex formation and subsequent nuclear translocation through both K48- and K63-linked deubiquitination. OTUD1-mediated SMAD3 activation regulates transcription of genes involved in vascular EndMT and remodeling in HUVECs. Finally, SMAD3 inhibition reverses OTUD1-promoted vascular remodeling. Our findings demonstrate that endothelial OTUD1 promotes Ang II-induced vascular remodeling by deubiquitinating SMAD3. We identify SMAD3 as a target of OTUD1 and propose OTUD1 as a potential therapeutic target for diseases related to vascular remodeling.

Plantamajoside attenuates cardiac fibrosis via inhibiting AGEs activated-RAGE/autophagy/EndMT pathway

Advanced glycation end products (AGEs) have been identified to transduce fibrogenic signals via inducing the activation of their receptor (RAGE)-mediated pathway. Recently, disrupting AGE-RAGE interaction has become a promising therapeutic strategy for chronic heart failure (CHF). Endothelial-to-mesenchymal transition (EndMT) is close to the cardiac fibrosis pathological process. Our previous studies have demonstrated that knockout RAGE suppressed the autophagy-mediated EndMT, and thus alleviated cardiac fibrosis. Plantamajoside (PMS) is the major bioactive compound of Plantago Asiatica, and its activity of anti-fibrosis has been documented in many reports. However, its effect on CHF and the underlying mechanism remains elusive. Thus, we tried to elucidate the protective role of PMS in CHF from the viewpoint of the AGEs/RAGE/autophagy/EndMT axis. Herein, PMS was found to attenuate cardiac fibrosis and dysfunction, suppress EndMT, reduce autophagy levels and serum levels of AGEs, yet did not affect the expression of RAGE in CHF mice. Mechanically, PMS possibly binds to the V-domain of RAGE, which is similar to the interaction between AGEs and RAGE. Importantly, this competitive binding disturbed AGEs-induced the RAGE-autophagy-EndMT pathway in vitro. Collectively, our results indicated that PMS might exert an anti-cardiac fibrosis effect by specifically binding RAGE to suppress the AGEs-activated RAGE/autophagy/EndMT pathway.

KRIT1: A Traffic Warden at the Busy Crossroads Between Redox Signaling and the Pathogenesis of Cerebral Cavernous Malformation Disease

Significance: KRIT1 (Krev interaction trapped 1) is a scaffolding protein that plays a critical role in vascular morphogenesis and homeostasis. Its loss-of-function has been unequivocally associated with the pathogenesis of Cerebral Cavernous Malformation (CCM), a major cerebrovascular disease of genetic origin characterized by defective endothelial cell-cell adhesion and ensuing structural alterations and hyperpermeability in brain capillaries. KRIT1 contributes to the maintenance of endothelial barrier function by stabilizing the integrity of adherens junctions and inhibiting the formation of actin stress fibers. Recent Advances: Among the multiple regulatory mechanisms proposed so far, significant evidence accumulated over the past decade has clearly shown that the role of KRIT1 in the stability of endothelial barriers, including the blood-brain barrier, is largely based on its involvement in the complex machinery governing cellular redox homeostasis and responses to oxidative stress and inflammation. KRIT1 loss-of-function has, indeed, been demonstrated to cause an impairment of major redox-sensitive mechanisms involved in spatiotemporal regulation of cell adhesion and signaling, which ultimately leads to decreased cell-cell junction stability and enhanced sensitivity to oxidative stress and inflammation. Critical Issues: This review explores the redox mechanisms that influence endothelial cell adhesion and barrier function, focusing on the role of KRIT1 in such mechanisms. We propose that this supports a novel model wherein redox signaling forms the common link between the various pathogenetic mechanisms and therapeutic approaches hitherto associated with CCM disease. Future Directions: A comprehensive characterization of the role of KRIT1 in redox control of endothelial barrier physiology and defense against oxy-inflammatory insults will provide valuable insights into the development of precision medicine strategies. Antioxid. Redox Signal. 38, 496-528.

Association of Placental Growth Factor and Angiopoietin in Human Retinal Endothelial Cell-Pericyte co-Cultures and iPSC-Derived Vascular Organoids

PURPOSE

Placental growth factor (PlGF) and Angiopoietin (Ang)-1 are two proteins that are involved in the regulation of endothelial cell (EC) growth and vasculature formation. In the retina and endothelial cells, pericytes are the major source of both molecules. The purpose of this study is to examine the association of PlGF and Ang-1 with human EC/pericyte co-cultures and iPSC-derived vascular organoids.

METHODS

In this study, we used co-cultures of human primary retinal endothelial cells (HREC) and primary human retinal pericytes (HRP), western blotting, immunofluorescent analysis, TUNEL staining, LDH-assays, and RNA seq analysis, as well as human-induced pluripotent stem cells (iPSC), derived organoids (VO) to study the association between PlGF and Ang-1.

RESULTS

Inhibition of PlGF by PlGF neutralizing antibody in HREC-HRP co-cultures resulted in the increased expression of Ang-1 and Tie-2 in a dose-dependent manner. This upregulation was not observed in HREC and HRP monocultures but only in co-cultures suggesting the association of pericytes and endothelial cells. Furthermore, Vascular endothelial growth factor receptor 1 (VEGFR1) inhibition abolished the Ang-1 and Tie-2 upregulation by PlGF inhibition. The pericyte viability in high-glucose conditions was also reduced by VEGFR1 neutralization. Immunofluorescent analysis showed that Ang-1 and Ang-2 were expressed mainly by perivascular cells in the VO. RNA seq analysis of the RNA isolated from VO in high glucose conditions indicated increased PlGF and Ang-2 expressions in the VO. PlGF inhibition increased the expression of Ang-1 and Tie-2 in VO, increasing the pericyte coverage of the VO microvascular network.

CONCLUSION

Combined, these results suggest PlGF's role in the regulation of Ang-1 and Tie-2 expression through VEGFR1. These findings provide new insights into the neovascularization process in diabetic retinopathy and new targets for potential therapeutic intervention.

Ubiquitin-specific protease 11 promotes partial epithelial-to-mesenchymal transition by deubiquitinating the epidermal growth factor receptor during kidney fibrosis

The aberrant expression of ubiquitin-specific protease 11 (USP11) is believed to be related to tumor progression. However, few studies have reported the biological function and clinical importance of USP11 in kidney fibrosis. Here, we demonstrated USP11 was highly upregulated in the kidneys from patients with chronic kidney disease and correlated positively with fibrotic lesion but negatively with kidney function. Conditional USP11 deletion or pharmacologic inhibition with Mitoxantrone attenuated pathological lesions and improved kidney function in both hyperuricemic nephropathy (HN)- and folic acid (FA)-induced mouse models of kidney fibrosis. Mechanistically, by RNA sequencing, USP11 was found to be involved in nuclear gene transcription of the epidermal growth factor receptor (EGFR). USP11 co-immunoprecipitated and co-stained with extra-nuclear EGFR and deubiquitinated and protected EGFR from proteasome-dependent degradation. Genetic or pharmacological depletion of USP11 facilitated EGFR degradation and abated augmentation of TGF-β1 and downstream signaling. This consequently alleviated the partial epithelial-mesenchymal transition, G2/M arrest and aberrant secretome of profibrogenic and proinflammatory factors in uric acid-stimulated tubular epithelial cells. Moreover, USP11 deletion had anti-fibrotic and anti-inflammatory kidney effects in the murine HN and FA models. Thus, our study provides evidence supporting USP11 as a promising target for minimizing kidney fibrosis and that inhibition of USP11 has potential to be an effective strategy for patients with chronic kidney disease.