TGF-ß1 dominates stromal fibroblast-mediated EMT via the FAP/VCAN axis in bladder cancer cells.

BACKGROUND: Bladder cancer is one of the most common malignant tumors of the urinary system and is associated with a poor prognosis once invasion and distant metastases occur. Epithelial-mesenchymal transition (EMT) drives metastasis and invasion in bladder cancer. Transforming growth factor ß1 (TGF-ß1) and stromal fibroblasts, especially cancer-associated fibroblasts (CAFs), are positive regulators of EMT in bladder cancer. However, it remains unclear how TGF-ß1 mediates crosstalk between bladder cancer cells and CAFs and how it induces stromal fibroblast-mediated EMT in bladder cancer. We aimed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. METHODS: Primary CAFs with high expression of fibroblast activation protein (FAP) were isolated from bladder cancer tissue samples. Subsequently, different conditioned media were used to stimulate the bladder cancer cell line T24 in a co-culture system. Gene set enrichment analysis, a human cytokine antibody array, and cytological assays were performed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. RESULTS: Among the TGF-ß family, TGF-ß1 was the most highly expressed factor in bladder cancer tissue and primary stromal fibroblast supernatant. In the tumor microenvironment, TGF-ß1 was mainly derived from stromal fibroblasts, especially CAFs. In stimulated bladder cells, stromal fibroblast-derived TGF-ß1 promoted bladder cancer cell migration, invasion, and EMT. Furthermore, TGF-ß1 promoted the activation of stromal fibroblasts, inducing CAF-like features, by upregulating FAP in primary normal fibroblasts and a normal fibroblast cell line. Stromal fibroblast-mediated EMT was induced in bladder cancer cells by TGF-ß1/FAP. Versican (VCAN), a downstream molecule of FAP, plays an essential role in TGF-ß1/FAP axis-induced EMT in bladder cancer cells. VCAN may also function through the PI3K/AKT1 signaling pathway. CONCLUSIONS: TGF-ß1 is a critical mediator of crosstalk between stromal fibroblasts and bladder cancer cells. We revealed a new mechanism whereby TGF-ß1 dominated stromal fibroblast-mediated EMT of bladder cancer cells via the FAP/VCAN axis and identified potential biomarkers (FAP, VCAN, N-cadherin, and Vimentin) of bladder cancer. These results enhance our understanding of bladder cancer invasion and metastasis and provide potential strategies for diagnosis, treatment, and prognosis.

Histone Variant H2A.Z Is Required for the Maintenance of Smooth Muscle Cell Identity as Revealed by Single-Cell Transcriptomics.

BACKGROUND: Histone variants endow chromatin with specific structures, and play essential roles in development and diseases. However, little is known about their roles in controlling cell identity in vascular diseases. METHODS: Given the cell heterogeneity in atherosclerotic lesions, we applied single-cell RNA-Sequencing to analyze diseased human arteries, and identified histone variant H2A.Z as a key histone signature to maintain vascular smooth muscle cell (VSMC) identity. RESULTS: We show that H2A.Z occupies genomic regions near VSMC marker genes, and its occupancy is decreased in VSMCs undergoing dedifferentiation. Mechanistically, H2A.Z occupancy preferentially promotes nucleosome turnover, and facilitates the recruitment of SMAD3 and MED1, thereby activating VSMC marker gene expression. In addition, H2A.Z expression is dramatically reduced at both mRNA and protein levels in diseased human vascular tissues compared to those in normal arteries. Notably, in vivo overexpression of H2A.Z rescues injury-induced loss of VSMC identity and neointima formation. CONCLUSIONS: Together, our data introduce dynamic occupancy of a histone variant as a novel regulatory basis contributing to cell fate decisions, and imply H2A.Z as a potential intervention node for vascular diseases.

Novel Adipokine, FAM19A5, Inhibits Neointima Formation After Injury Through Sphingosine-1-Phosphate Receptor 2.

BACKGROUND: Obesity plays crucial roles in the development of cardiovascular diseases. However, the mechanisms that link obesity and cardiovascular diseases remain elusive. Compelling evidence indicates that adipokines play an important role in obesity-related cardiovascular diseases. Here, we found a new adipokine-named family with sequence similarity 19, member A5 (FAM19A5), a protein with unknown function that was predicted to be distantly related to the CC-chemokine family. We aimed to test whether adipose-derived FAM19A5 regulates vascular pathology on injury. METHODS: DNA cloning, protein expression, purification, and N-terminal sequencing were applied to characterize FAM19A5. Adenovirus infection and siRNA transfection were performed to regulate FAM19A5 expression. Balloon and wire injury were performed in vivo on the rat carotid arteries and mouse femoral arteries, respectively. Bioinformatics analysis, radioactive ligand-receptor binding assays, receptor internalization, and calcium mobilization assays were used to identify the functional receptor for FAM19A5. RESULTS: We first characterized FAM19A5 as a secreted protein, and the first 43 N-terminal amino acids were the signal peptides. Both FAM19A5 mRNA and protein were abundantly expressed in the adipose tissue but were downregulated in obese mice. Overexpression of FAM19A5 markedly inhibited vascular smooth muscle cell proliferation and migration and neointima formation in the carotid arteries of balloon-injured rats. Accordingly, FAM19A5 silencing in adipocytes significantly promoted vascular smooth muscle cell activation. Adipose-specific FAM19A5 transgenic mice showed greater attenuation of neointima formation compared with wild-type littermates fed with or without Western-style diet. We further revealed that sphingosine-1-phosphate receptor 2 was the functional receptor for FAM19A5, with a dissociation constant (Kd) of 0.634 nmol/L. Inhibition of sphingosine-1-phosphate receptor 2 or its downstream G12/13-RhoA signaling circumvented the suppressive effects of FAM19A5 on vascular smooth muscle cell proliferation and migration. CONCLUSIONS: We revealed that a novel adipokine, FAM19A5, was capable of inhibiting postinjury neointima formation via sphingosine-1-phosphate receptor 2-G12/13-RhoA signaling. Downregulation of FAM19A5 during obesity may trigger cardiometabolic diseases.

Deficiency of FAM3D (Family With Sequence Similarity 3, Member D), A Novel Chemokine, Attenuates Neutrophil Recruitment and Ameliorates Abdominal Aortic Aneurysm Development.

OBJECTIVE: Chemokine-mediated neutrophil recruitment contributes to the pathogenesis of abdominal aortic aneurysm (AAA) and may serve as a promising therapeutic target. FAM3D (family with sequence similarity 3, member D) is a recently identified novel chemokine. Here, we aimed to explore the role of FAM3D in neutrophil recruitment and AAA development. APPROACH AND RESULTS: FAM3D was markedly upregulated in human AAA tissues, as well as both elastase- and CaPO4-induced mouse aneurysmal aortas. FAM3D deficiency significantly attenuated the development of AAA in both mouse models. Flow cytometry analysis indicated that FAM3D-/- mice exhibited decreased neutrophil infiltration in the aorta during the early stage of AAA formation compared with their wild-type littermates. Moreover, application of FAM3D-neutralizing antibody 6D7 through intraperitoneal injection markedly ameliorated elastase-induced AAA formation and neutrophil infiltration. Further, in vitro coculture experiments with FAM3D-neutralizing antibody 6D7 and in vivo intravital microscopic analysis indicated that endothelial cell-derived FAM3D induced neutrophil recruitment. Mechanistically, FAM3D upregulated and activated Mac-1 (macrophage-1 antigen) in neutrophils, whereas inhibition of FPR1 (formyl peptide receptor 1) or FPR2 significantly blocked FAM3D-induced Mac-1 activation, indicating that the effect of FAM3D was dependent on both FPRs. Moreover, specific inhibitors of FPR signaling related to Gi protein or ß-arrestin inhibited FAM3D-activated Mac-1 in vitro, whereas FAM3D deficiency decreased the activation of both FPR-Gi protein and ß-arrestin signaling in neutrophils in vivo. CONCLUSIONS: FAM3D, as a dual agonist of FPR1 and FPR2, induced Mac-1-mediated neutrophil recruitment and aggravated AAA development through FPR-related Gi protein and ß-arrestin signaling.

CYLD Deubiquitinates Nicotinamide Adenine Dinucleotide Phosphate Oxidase 4 Contributing to Adventitial Remodeling.

OBJECTIVE: Transdifferentiation of adventitial fibroblasts (AFs) into myofibroblasts plays a critical role during the vascular remodeling that occurs during atherosclerosis, restenosis, and aortic aneurysm. The ubiquitination/deubiquitination regulatory system is essential for the quality control of proteins. The involvement of ubiquitination/deubiquitination during AF transdifferentiation remains largely unknown. In this study, we determined the role of cylindromatosis (CYLD), a deubiquitinase, in the process of AF differentiation and activation in vitro and in vivo. APPROACH AND RESULTS: Transforming growth factor-ß1 and homocysteine, 2 known inducers of AF transdifferentiation, greatly upregulated CYLD expression in a time- and dose-dependent manner. The silencing of CYLD significantly inhibited AF transdifferentiation and activation as evidenced by the expression of contractile proteins, the production of the proinflammatory cytokines MCP-1 (monocyte chemotactic protein 1) and IL-6 (interleukin-6), the deposition of extracellular matrix, and cell migration. We further asked whether CYLD mediates AF activation via the regulation of nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) as it is an essential factor during AF transdifferentiation. Indeed, the silencing of CYLD repressed transforming growth factor-ß1-induced and homocysteine-induced Nox4 upregulation and reactive oxygen species production, whereas Nox4 overexpression greatly rescued the inhibitory effect on AF activation by CYLD silencing. Most interestingly, transforming growth factor-ß1 and homocysteine repressed Nox4 ubiquitination and prolonged the half-life of Nox4. Moreover, Nox4 was deubiquitinated via a direct interaction with the ubiquitin-specific protease domain of CYLD. In accordance, hyperhomocysteinemia significantly increased adventitial CYLD and Nox4 expression, promoted AF transdifferentiation, and aggravated CaPO4-induced abdominal aortic aneurysm in mice. These effects were abolished in CYLD-/- mice. CONCLUSIONS: CYLD contributes to the transdifferentiation of AFs via deubiquitinating Nox4 and may play a role in vascular remodeling.

ADAMTS-7 inhibits re-endothelialization of injured arteries and promotes vascular remodeling through cleavage of thrombospondin-1.

BACKGROUND: ADAMTS-7, a member of the disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, was recently identified to be significantly associated genomewide with coronary artery disease. However, the mechanisms that link ADAMTS-7 and coronary artery disease risk remain elusive. We have previously demonstrated that ADAMTS-7 promotes vascular smooth muscle cell migration and postinjury neointima formation via degradation of a matrix protein cartilage oligomeric matrix protein. Because delayed endothelium repair renders neointima and atherosclerosis plaque formation after vessel injury, we examined whether ADAMTS-7 also inhibits re-endothelialization. METHODS AND RESULTS: Wire injury of the carotid artery and Evans blue staining were performed in Adamts7(-/-) and wild-type mice. Adamts-7 deficiency greatly promoted re-endothelialization at 3, 5, and 7 days after injury. Consequently, Adamts-7 deficiency substantially ameliorated neointima formation in mice at days 14 and 28 after injury in comparison with the wild type. In vitro studies further indicated that ADAMTS-7 inhibited both endothelial cell proliferation and migration. Surprisingly, cartilage oligomeric matrix protein deficiency did not affect endothelial cell proliferation/migration and re-endothelialization in mice. In a further examination of other potential vascular substrates of ADAMTS-7, a label-free liquid chromatography-tandem mass spectrometry secretome analysis revealed thrombospondin-1 as a potential ADAMTS-7 target. The subsequent studies showed that ADAMTS-7 was directly associated with thrombospondin-1 by its C terminus and degraded thrombospondin-1 in vivo and in vitro. The inhibitory effect of ADAMTS-7 on postinjury endothelium recovery was circumvented in Tsp1(-/-) mice. CONCLUSIONS: Our study revealed a novel mechanism by which ADAMTS-7 affects neointima formation. Thus, ADAMTS-7 is a promising treatment target for postinjury vascular intima hyperplasia.

Targeting macrophage TFEB-14-3-3 epsilon Interface by naringenin inhibits abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a lethal cardiovascular disease, and there is no proven drug treatment for this condition. In this study, by using the Connectivity Map (CMap) approach, we explored naringenin, a naturally occurring citrus flavonoid, as a putative agent for inhibiting AAA. We then validated the prediction with two independent mouse models of AAA, calcium phosphate (CaPO4)-induced C57BL/6J mice and angiotensin II-infused ApoE-/- mice. Naringenin effectively blocked the formation of AAAs and the progression of established AAAs. Transcription factor EB (TFEB) is the master regulator of lysosome biogenesis. Intriguingly, the protective role of naringenin on AAA was abolished by macrophage-specific TFEB depletion in mice. Unbiased interactomics, combined with isothermal titration calorimetry (ITC) and cellular thermal shift assays (CETSAs), further revealed that naringenin is directly bound to 14-3-3 epsilon blocked the TFEB-14-3-3 epsilon interaction, and therefore promoted TFEB nuclear translocation and activation. On one hand, naringenin activated lysosome-dependent inhibition of the NLRP3 inflammasome and repressed aneurysmal inflammation. On the other hand, naringenin induced TFEB-dependent transcriptional activation of GATA3, IRF4, and STAT6 and therefore promoted reparative M2 macrophage polarization. In summary, naturally derived naringenin or macrophage TFEB activation shows promising efficacy for the treatment of AAA.

Long noncoding RNA NORAD acts as a ceRNA mediates gemcitabine resistance in bladder cancer by sponging miR-155-5p to regulate WEE1 expression.

BACKGROUND: Increasing evidences have proved that long noncoding RNAs (lncRNAs) regulate the occurrence of bladder cancer (BC) and participate in various pathophysiology processes. However, little is unknown about the role of lncRNAs in drug resistance of BC cells. In this study, we explored the role of non-coding RNA activated by DNA damage (NORAD) in the gemcitabine (GEM) resistant of BC cells and explored its potential mechanism. METHODS: Real-time quantitative PCR (RT-qPCR) was used to detect the expression of NORAD and miR-155-5p of BC cells. Cell counting kit-8 (CCK-8) and Western blot were used to detect cell inhibition rate and the expression of WEE1 G2 checkpoint kinase (WEE1), P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Flow cytometry detected cell cycle and apoptosis. Dual luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were used to confirm the targeting relationship between miR-155-5p, NORAD and WEE1. The xenograft model was used to observe the function of NORAD in vivo. immunohistochemistry (IHC) assay was used to detect the expression of WEE1, caspase-3 and Ki67 in tumor tissues. RESULTS: NORAD highly expressed in GEM-resistant BC cell lines. Knockdown of NORAD significantly inhibited the proliferation of T24/GEM cells, the expression of drug-resistant proteins P-gp and MRP1, inhibit the G0/G1 phase of cells, and induce cell apoptosis. Knockdown of NORAD reversed the promotion effect of miR-155-5p on WEE1 expression and promoted the sensitivity of T24/GEM cells to GEM. In vivo, knockdown of NORAD inhibited the tumor growth, and enhanced the GEM-sensitivity in mice. CONCLUSION: These data highlight the potential of NORAD acts as a therapeutic target for BC GEM resistance. It revealed the vital roles of NORAD/miR-155-5p/WEE1 axis in GEM resistant BC cells, providing a novel therapeutic strategy for BC.

COMP-prohibitin 2 interaction maintains mitochondrial homeostasis and controls smooth muscle cell identity.

Vascular smooth muscle cells (VSMCs) are highly phenotypically plastic, and loss of the contractile phenotype in VSMCs has been recognized at the early onset of the pathology of a variety of vascular diseases. However, the endogenous regulatory mechanism to maintain contractile phenotype in VSMCs remains elusive. Moreover, little has been known about the role of the mitochondrial bioenergetics in terms of VSMC homeostasis. Herein, we asked if glycoprotein COMP (Cartilage oligomeric matrix protein) is involved in mitochondrial bioenergetics and therefore regulates VSMCs homeostasis. By using fluorescence assay, subcellular western blot and liquid chromatography tandem mass spectrometry analysis, we found that extracellular matrix protein COMP unexpectedly localized within mitochondria. Further mitochondrial transplantation revealed that both mitochondrial and non-mitochondrial COMP maintained VSMC identity. Moreover, microarray analysis revealed that COMP deficiency impaired mitochondrial oxidative phosphorylation in VSMCs. Further study confirmed that COMP deficiency caused mitochondrial oxidative phosphorylation dysfunction accompanied by morphological abnormality. Moreover, the interactome of mitochondrial COMP revealed that COMP interacted with prohibitin 2, and COMP-prohibitin 2 interaction maintained mitochondrial homeostasis. Additionally, disruption of COMP-prohibitin 2 interaction caused VSMC dedifferentiation in vitro and enhanced the neointima formation post rat carotid artery injury in vivo. In conclusion, COMP-prohibitin 2 interaction in mitochondria plays an important role in maintaining the contractile phenotype of VSMCs by regulating mitochondrial oxidative phosphorylation. Maintaining the homeostasis of mitochondrial respiration through COMP-prohibitin 2 interaction may shed light on prevention of vascular disease.

Homocysteine directly interacts and activates the angiotensin II type I receptor to aggravate vascular injury.

Hyperhomocysteinemia (HHcy) is a risk factor for various cardiovascular diseases. However, the mechanism underlying HHcy-aggravated vascular injury remains unclear. Here we show that the aggravation of abdominal aortic aneurysm by HHcy is abolished in mice with genetic deletion of the angiotensin II type 1 (AT1) receptor and in mice treated with an AT1 blocker. We find that homocysteine directly activates AT1 receptor signalling. Homocysteine displaces angiotensin II and limits its binding to AT1 receptor. Bioluminescence resonance energy transfer analysis reveals distinct conformational changes of AT1 receptor upon binding to angiotensin II and homocysteine. Molecular dynamics and site-directed mutagenesis experiments suggest that homocysteine regulates the conformation of the AT1 receptor both orthosterically and allosterically by forming a salt bridge and a disulfide bond with its Arg167 and Cys289 residues, respectively. Together, these findings suggest that strategies aimed at blocking the AT1 receptor may mitigate HHcy-associated aneurysmal vascular injuries.