A MicroRNA302-367-Erk1/2-Klf2-S1pr1 Pathway Prevents Tumor Growth via Restricting Angiogenesis and Improving Vascular Stability

A detrimental role of endothelial S1PR2 in cardiac ischemia-reperfusion injury via modulating mitochondrial dysfunction, NLRP3 inflammasome activation, and pyroptosis

Sphingosine 1-phosphate (S1P), a bioactive lipid molecule, exerts multifaceted effects on cardiovascular functions via S1P receptors, but its effects on cardiac I/R injury are not fully understood. Plasma lipidomics analysis by mass spectrometry revealed that sphingosine lipids, including sphingosine 1-phosphate (S1P), were significantly down-regulated following cardiac I/R injury in mice. The reduced S1P levels were also observed in the plasma of coronary heart disease (CHD) patients after percutaneous coronary intervention (PCI) compared with those without PCI. We found that S1P exerted a cardioprotective effect via endothelial cell (EC)-S1PR1, whereas EC-S1PR2 displayed a detrimental effect on cardiac I/R. Our data showed that EC-specific S1pr2 loss-of-function significantly lessened inflammatory responses and diminished cardiac I/R injury, while EC-specific S1pr2 gain-of-function aggravated cardiac I/R injury. Mechanistically, EC-S1PR2 initiated excessive mitochondrial fission and elevated ROS production via RHO/ROCK1/DRP1 pathway, leading to NLRP3 inflammasome activation and subsequent cell pyroptosis, thereby exacerbating inflammation and I/R injuries. Furthermore, RGD-peptide magnetic nanoparticles packaging S1pr2-siRNA to specifically knockdown S1PR2 in endothelial cells significantly ameliorated cardiac I/R injury. Taken together, our investigations demonstrate that EC-S1PR2 induces excessive mitochondrial fission, which results in NLRP3 inflammasome activation and subsequently triggers cell pyroptosis, ultimately exacerbating inflammatory responses and aggravating heart injuries following I/R.

Therapeutic efficacy of ECs Foxp1 targeting Hif1α-Hk2 glycolysis signal to restrict angiogenesis

Endothelial cells (ECs) rely on glycolysis for energy production to maintain vascular homeostasis and the normalization of hyperglycolysis in tumor vessels has recently gained attention as a therapeutic target. We analyzed the TCGA database and found reduced Foxp1 expression in lung carcinoma. Immunostaining demonstrated reduced expression more restricted at tumor vascular ECs. Therefore, we investigated the function and mechanisms of Foxp1 in EC metabolism for tumor angiogenesis required for tumor growth. EC-Foxp1 deletion mice exhibited a significant increase of tumor and retinal developmental angiogenesis and Hif1α was identified as Foxp1 target gene, and Hk2 as Hif1α target gene. The Foxp1-Hif1α-Hk2 pathway in ECs is important in the regulation of glycolytic metabolism to govern tumor angiogenesis. Finally, we used genetic deletion of EC-Hif1α and RGD-peptide nanoparticles EC target delivery of Hif1α/Hk2-siRNAs to knockdown gene expression which reduced the tumor EC hyperglycolysis state and restricted angiogenesis for tumor growth. This study advances our understanding of EC metabolism for tumor angiogenesis, and meanwhile provides evidence for future therapeutic intervention of hyperglycolysis in tumor ECs for suppression of tumor growth.

The co-location of CD14+APOE+ cells and MMP7+ tumour cells contributed to worse immunotherapy response in non-small cell lung cancer

Intra-tumour immune infiltration is a crucial determinant affecting immunotherapy response in non-small cell lung cancer (NSCLC). However, its phenotype and related spatial structure have remained elusive. To overcome these restrictions, we undertook a comprehensive study comprising spatial transcriptomic (ST) data (28 712 spots from six samples). We identified two distinct intra-tumour infiltration patterns: immune exclusion (characterised by myeloid cells) and immune activation (characterised by plasma cells). The immune exclusion and immune activation signatures showed adverse and favourable roles in NSCLC patients' survival, respectively. Notably, CD14+APOE+ cells were recognised as the main cell type in immune exclusion samples, with increased epithelial‒mesenchymal transition and decreased immune activities. The co-location of CD14+APOE+ cells and MMP7+ tumour cells was observed in both ST and bulk transcriptomics data, validated by multiplex immunofluorescence performed on 20 NSCLC samples. The co-location area exhibited the upregulation of proliferation-related pathways and hypoxia activities. This co-localisation inhibited T-cell infiltration and the formation of tertiary lymphoid structures. Both CD14+APOE+ cells and MMP7+ tumour cells were associated with worse survival. In an immunotherapy cohort from the ORIENT-3 clinical trial, NSCLC patients who responded unfavourably exhibited higher infiltration of CD14+APOE+ cells and MMP7+ tumour cells. Within the co-location area, the MK, SEMA3 and Macrophage migration inhibitory factor (MIF) signalling pathway was most active in cell‒cell communication. This study identified immune exclusion and activation patterns in NSCLC and the co-location of CD14+APOE+ cells and MMP7+ tumour cells as contributors to immune resistance.

Molecular subtyping and characterization of clear cell renal cell carcinoma by tumor differentiation trajectories

Previous bulk RNA sequencing or whole genome sequencing on clear cell renal cell carcinoma (ccRCC) subtyping mainly focused on ccRCC cell origin or the complex tumor microenvironment (TME). Based on the single-cell RNA sequencing (scRNA-seq) data of 11 primary ccRCC specimens, cancer stem-cell-like subsets could be differentiated into five trajectories, whereby we further classified ccRCC cells into three groups with diverse molecular features. These three ccRCC subgroups showed significantly different outcomes and potential targets to tyrosine kinase inhibitors (TKIs) or immune checkpoint inhibitors (ICIs). Tumor cells in three differentiation directions exhibited distinct interactions with other subsets in the ccRCC niches. The subtyping model was examined through immunohistochemistry staining in our ccRCC cohort and validated the same classification effect as the public patients. All these findings help gain a deeper understanding about the pathogenesis of ccRCC and provide useful clues for optimizing therapeutic schemes based on the molecular subtype analysis.

MicroRNAs in Tumor Endothelial Cells: Regulation, Function and Therapeutic Applications

Tumor endothelial cells (TECs) are key stromal components of the tumor microenvironment, and are essential for tumor angiogenesis, growth and metastasis. Accumulating evidence has shown that small single-stranded non-coding microRNAs (miRNAs) act as powerful endogenous regulators of TEC function and blood vessel formation. This systematic review provides an up-to-date overview of these endothelial miRNAs. Their expression is mainly regulated by hypoxia, pro-angiogenic factors, gap junctions and extracellular vesicles, as well as long non-coding RNAs and circular RNAs. In preclinical studies, they have been shown to modulate diverse fundamental angiogenesis-related signaling pathways and proteins, including the vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) pathway; the rat sarcoma virus (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway; the phosphoinositide 3-kinase (PI3K)/AKT pathway; and the transforming growth factor (TGF)-β/TGF-β receptor (TGFBR) pathway, as well as krüppel-like factors (KLFs), suppressor of cytokine signaling (SOCS) and metalloproteinases (MMPs). Accordingly, endothelial miRNAs represent promising targets for future anti-angiogenic cancer therapy. To achieve this, it will be necessary to further unravel the regulatory and functional networks of endothelial miRNAs and to develop safe and efficient TEC-specific miRNA delivery technologies.

Dialogue between VE-Cadherin and Sphingosine 1 Phosphate Receptor1 (S1PR1) for Protecting Endothelial Functions

The endothelial cells (EC) of established blood vessels in adults remain extraordinarily quiescent in the sense that they are not actively proliferating, but they fulfill the necessary role to control the permeability of their monolayer that lines the interior of blood vessels. The cell-cell junctions between ECs in the endothelium comprise tight junctions and adherens homotypic junctions, which are ubiquitous along the vascular tree. Adherens junctions are adhesive intercellular contacts that are crucial for the organization of the EC monolayer and its maintenance and regulation of normal microvascular function. The molecular components and underlying signaling pathways that control the association of adherens junctions have been described in the last few years. In contrast, the role that dysfunction of these adherens junctions has in contributing to human vascular disease remains an important open issue. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid mediator found at high concentrations in blood which has important roles in the control of the vascular permeability, cell recruitment, and clotting that follow inflammatory processes. This role of S1P is achieved through a signaling pathway mediated through a family of G protein-coupled receptors designated as S1PR1. This review highlights novel evidence for a direct linkage between S1PR1 signaling and the mediation of EC cohesive properties that are controlled by VE-cadherin.

Lung Cancer Gene Regulatory Network of Transcription Factors Related to the Hallmarks of Cancer

The transcriptomic analysis of microarray and RNA-Seq datasets followed our own bioinformatic pipeline to identify a transcriptional regulatory network of lung cancer. Twenty-six transcription factors are dysregulated and co-expressed in most of the lung cancer and pulmonary arterial hypertension datasets, which makes them the most frequently dysregulated transcription factors. Co-expression, gene regulatory, coregulatory, and transcriptional regulatory networks, along with fibration symmetries, were constructed to identify common connection patterns, alignments, main regulators, and target genes in order to analyze transcription factor complex formation, as well as its synchronized co-expression patterns in every type of lung cancer. The regulatory function of the most frequently dysregulated transcription factors over lung cancer deregulated genes was validated with ChEA3 enrichment analysis. A Kaplan-Meier plotter analysis linked the dysregulation of the top transcription factors with lung cancer patients' survival. Our results indicate that lung cancer has unique and common deregulated genes and transcription factors with pulmonary arterial hypertension, co-expressed and regulated in a coordinated and cooperative manner by the transcriptional regulatory network that might be associated with critical biological processes and signaling pathways related to the acquisition of the hallmarks of cancer, making them potentially relevant tumor biomarkers for lung cancer early diagnosis and targets for the development of personalized therapies against lung cancer.

Identification of PTPN22 as a potential genetic biomarker for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe life-threatening disease that is generally asymptomatic and is diagnosed at a very late stage. The genetic component underpinning AAA is considerable, with an estimated heritability of up to 70%. Therefore, identifying genetic biomarkers for AAA is valuable for predicting high-risk populations. We used integrative bioinformatics and cellular AAA model-based validation to reveal that the gene encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) may be a potentially useful diagnostic biomarker for AAA. Integrative bioinformatics analyses of clinical specimens showed that PTPN22 expression was consistently upregulated in aortic tissues and peripheral blood mononuclear cells (PBMCs) derived from patients with AAA. Moreover, transcriptomics data revealed that PTPN22 is a potential biomarker for AAA with limited diagnostic value in patients with thoracic aortic aneurysm/dissection. Single-cell RNA sequencing-based findings further highlight PTPN22 expression in aortic immune cells and vascular smooth muscle cells (VSMCs) is consistently upregulated in patients with AAA. A cellular AAA model was eventually employed to verify the increase in PTPN22 expression. Collectively, the results indicate that PTPN22 could be a potentially useful diagnostic biomarker for AAA.

Lymphatic endothelial sphingosine 1-phosphate receptor 1 enhances macrophage clearance via lymphatic system following myocardial infarction

Lymphatic endothelial cell homeostasis plays important roles in normal physiological cardiac functions, and its dysfunction significantly influences pathological cardiac remodeling after myocardial infarction (MI). Our results revealed that sphingosine 1-phosphate receptor 1 (S1pr1) expression in cardiac lymphatic endothelial cells (LECs) was sharply changed after MI. It has been shown that S1pr1 tightly controlled LEC functions and homeostasis. We thus hypothesized that lymphatic endothelial S1pr1 might be involved in post-MI cardiac remodeling. We generated LEC-conditional S1pr1 transgenic mice, in which S1pr1 expression was reduced in cardiac LECs. We performed the left anterior descending coronary artery (LAD) ligation operation to induce MI in these mice. Cardiac functions and remodeling were examined by echocardiography analysis and serial histological analysis. Meanwhile, we performed adoptive cell transfer experiments to monitor macrophage trafficking in post-MI myocardium and their draining lymphatic system. Furthermore, in vitro cell culture experiments and mechanism studies were undertaken to uncover the molecular mechanism by which LEC-S1pr1 regulated cardiac inflammation and remodeling after MI. Our results showed that S1pr1 expression significantly decreased in cardiac LECs after MI. Our in vivo experiments showed that the reduced expression of LEC-S1pr1 deteriorated cardiac function and worsened pathological cardiac remodeling after MI. Our further results demonstrated that the reduced expression of LEC-S1pr1 did not influence macrophage infiltration in an early inflammatory phase of MI, but significantly affected macrophages clearance in the later phase of MI via afferent cardiac lymphatics, and thus influenced inflammatory responses and cardiac outcome after MI. Further study showed that S1P/S1pr1 activated ERK signaling pathway and enhanced CCL2 expression, which promoted macrophage trafficking in a paracrine manner. This study reveals that cardiac lymphatic endothelial cells tightly control macrophage trafficking via lymphatic vessels in injured hearts via S1P/S1pr1/ERK/CCL2 pathway and thus regulate post-MI immune modulation and heart repair. This study highlights the importance of cardiac lymphatic vessel system in orchestrating post-MI immune responses and cardiac remodeling by regulating macrophage transit in injured hearts. Our finding implies that a feasible modulation of S1pr1 signaling in LECs might provide a promising target to resolve excessive inflammation and to ameliorate adverse cardiac remodeling after MI.

Endothelial Foxp1 Regulates Neointimal Hyperplasia Via Matrix Metalloproteinase-9/Cyclin Dependent Kinase Inhibitor 1B Signal Pathway

Background The endothelium is essential for maintaining vascular physiological homeostasis and the endothelial injury leads to the neointimal hyperplasia because of the excessive proliferation of vascular smooth muscle cells. Endothelial Foxp1 (forkhead box P1) has been shown to control endothelial cell (EC) proliferation and migration in vitro. However, whether EC-Foxp1 participates in neointimal formation in vivo is not clear. Our study aimed to investigate the roles and mechanisms of EC-Foxp1 in neointimal hyperplasia. Methods and Results The wire injury femoral artery neointimal hyperplasia model was performed in Foxp1 EC-specific loss-of-function and gain-of-function mice. EC-Foxp1 deletion mice displayed the increased neointimal formation through elevation of vascular smooth muscle cell proliferation and migration, and the reduction of EC proliferation hence reendothelialization after injury. In contrast, EC-Foxp1 overexpression inhibited the neointimal formation. EC-Foxp1 paracrine regulated vascular smooth muscle cell proliferation and migration via targeting matrix metalloproteinase-9. Also, EC-Foxp1 deletion impaired EC repair through reduction of EC proliferation via increasing cyclin dependent kinase inhibitor 1B expression. Delivery of cyclin dependent kinase inhibitor 1B-siRNA to ECs using RGD (Arg-Gly-Asp)-peptide magnetic nanoparticle normalized the EC-Foxp1 deletion-mediated impaired EC repair and attenuated the neointimal formation. EC-Foxp1 regulates matrix metalloproteinase-9/cyclin dependent kinase inhibitor 1B signaling pathway to control injury induced neointimal formation. Conclusions Our study reveals that targeting EC-Foxp1-matrix metalloproteinase-9/cyclin dependent kinase inhibitor 1B pathway might provide future novel therapeutic interventions for restenosis.

Endothelial S1pr2 regulates post-ischemic angiogenesis via AKT/eNOS signaling pathway

Aims: It is important to understand the mechanism that regulates post-ischemic angiogenesis and to explore a new therapeutic target for an effective improvement of revascularization in peripheral artery disease (PAD) patients. Post-ischemic angiogenesis is a highly orchestrated process, which involves vascular endothelial cells (ECs) proliferation, migration and assembly into capillaries. We found a significant reduction of S1pr2 (sphingosine 1-phosphate receptor 2) in endothelial cells after hindlimb ischemia (HLI). We thus hypothesized that EC-S1pr2 might be involved in the regulation of post-ischemic angiogenesis and blood flow recovery during peripheral arterial disease (PAD). Methods and Results: We generated both EC-specific S1pr2 loss-of-function and S1pr2 gain-of-function mice. Our study showed that EC-specific S1pr2 loss-of-function significantly enhanced post-ischemic angiogenesis and improved blood flow recovery upon femoral artery ligation, whereas the EC-specific S1pr2 gain-of-function severely hindered post-ischemic angiogenesis and reduced blood flow recovery in ischemic limbs. We next identified that S1pr2 inhibited AKT/eNOS signaling pathway, and thus inhibited EC proliferation/migration and angiogenic activity. As expected, pharmacological inhibition of S1pr2 by JTE013 improved post-ischemic angiogenesis and improved blood flow perfusion after femoral artery ligation. Moreover, we developed RGD-peptide magnetic nanoparticles packaging S1pr2-siRNA which specifically targeted ECs and achieved an efficient silencing of S1pr2 expression in ECs in vivo. This EC-targeted strategy to dampen S1pr2 significantly enhanced post-ischemic angiogenesis and boosted blood perfusion after HLI, supplying a novel therapy target for patients with peripheral arterial disease. Conclusions: This present study demonstrates that EC-expressing S1pr2 tightly controls post-ischemic angiogenesis and blood flow perfusion recovery. This research provides a novel strategy for EC-target knockdown of S1pr2 as a new therapeutic intervention for patients with peripheral artery disease.

S1PR2/RhoA/ROCK1 pathway promotes inflammatory bowel disease by inducing intestinal vascular endothelial barrier damage and M1 macrophage polarization

Vascular and immune dysfunctions are thought to be related to the pathogenesis of inflammatory bowel disease (IBD), but behind this, the exact mechanism of mucosal vascular endothelial barrier dysfunction and macrophage phenotypic transition is not fully understood. Here, we explored the mechanistic role of sphingosine 1-phosphate receptor 2 (S1PR2) and its downstream G protein RhoA/Rho kinase 1 (ROCK1) signaling pathway in the intestinal endothelial barrier damage and M1 macrophage polarization in IBD. We found that the expression of S1PR2 in intestinal mucosal vascular endothelial cells and macrophages of IBD patients and DSS-induced colitis mice as well as vascular endothelial cells and macrophages treated with LPS in vitro was significantly increased. Knocking down or pharmacologically inhibiting S1PR2 significantly downregulated the expression of RhoA and ROCK1 in vascular endothelial cells and macrophages. Furthermore, inhibition of S1PR2 and ROCK1 reversed the impaired vascular barrier function and M1 macrophage polarization in vivo and in vitro, while reducing ER stress in vascular endothelial cells and glycolysis in macrophages. In addition, inhibition of ER stress or glycolysis reversed LPS-induced impairment of vascular endothelial cell barrier function and M1 macrophage polarization. Collectively, our results indicate that the S1PR2/RhoA/ROCK1 signaling pathway may participate in the pathogenesis of IBD by regulating vascular endothelial barrier function and M1 macrophage polarization.

Interaction of microRNAs with sphingosine kinases, sphingosine-1 phosphate, and sphingosine-1 phosphate receptors in cancer

Sphingosine-1-phosphate (S1P), a pleiotropic lipid mediator, participates in various cellular processes during tumorigenesis, including cell proliferation, survival, drug resistance, metastasis, and angiogenesis. S1P is formed by two sphingosine kinases (SphKs), SphK1 and SphK2. The intracellularly produced S1P is delivered to the extracellular space by ATP-binding cassette (ABC) transporters and spinster homolog 2 (SPNS2), where it binds to five transmembrane G protein-coupled receptors to mediate its oncogenic functions (S1PR1-S1PR5). MicroRNAs (miRNAs) are small non-coding RNAs, 21-25 nucleotides in length, that play numerous crucial roles in cancer, such as tumor initiation, progression, apoptosis, metastasis, and angiogenesis via binding to the 3'-untranslated region (3'-UTR) of the target mRNA. There is growing evidence that various miRNAs modulate tumorigenesis by regulating the expression of SphKs, and S1P receptors. We have reviewed various roles of miRNAs, SphKs, S1P, and S1P receptors (S1PRs) in malignancies and how notable miRNAs like miR-101, miR-125b, miR-128, and miR-506, miR-1246, miR-21, miR-126, miR499a, miR20a-5p, miR-140-5p, miR-224, miR-137, miR-183-5p, miR-194, miR181b, miR136, and miR-675-3p, modulate S1P signaling. These tumorigenesis modulating miRNAs are involved in different cancers including breast, gastric, hepatocellular carcinoma, prostate, colorectal, cervical, ovarian, and lung cancer via cell proliferation, invasion, angiogenesis, apoptosis, metastasis, immune evasion, chemoresistance, and chemosensitivity. Therefore, understanding the interaction of SphKs, S1P, and S1P receptors with miRNAs in human malignancies will lead to better insights for miRNA-based cancer therapy.

MiR-302b Suppresses Tumor Metastasis by Targeting Frizzled 6 in OSCC

Oral squamous cell carcinoma (OSCC) accounts for approximately 90% of malignant epithelial tumors of the oral and maxillofacial region. OSCC has high rate of metastasis and poor prognosis. Tobacco and/or alcohol consumption and human papillomavirus infection are relatively exact susceptibility factors for OSCC, but the specific process of oral mucosal carcinogenesis and progression is very complicated. microRNA-302b (miR-302b) could regulate various characteristics of many tumor cells, such as proliferation and apoptosis, but its role and mechanism in OSCC have not been reported. This research aims to study the effect of miR-302b on the invasion and migration ability of OSCC and the mechanism by which it functions as well as to identify new prognostic indicators and therapeutic targets for OSCC patients. Functional studies showed that the miR-302b level was negatively correlated with the invasion and migration ability of OSCC. The studies also showed that the overexpression of miR-302b could attenuate the invasion and migration ability of OSCC cells and reduce lymphangiogenesis and the lung metastasis rate of OSCC cells in a mouse model. Mechanistic studies were performed by quantitative polymerase chain reactions, luciferase assays, and RNA pull-down experiments. The results verified that frizzled class receptor 6 (FZD6) is a target gene of miR-302b in OSCC that could promote cell invasion and migration. Clinical studies demonstrate that the protein expression level of FZD6 was higher in OSCC and metastatic lymph nodes than in normal oral mucosa epithelium. Taken together, these data showed that miR-302b could inhibit the invasion and migration ability of OSCC cells by targeting and downregulating FZD6, thereby inhibiting OSCC metastasis. As a new target gene of miR-302b, FZD6 has the potential to become a prognostic and therapeutic target for OSCC patients.

Vascular endothelial S1pr1 ameliorates adverse cardiac remodelling via stimulating reparative macrophage proliferation after myocardial infarction

AIMS

Endothelial cell (EC) homoeostasis plays an important role in normal physiological cardiac functions, and its dysfunction significantly influences pathological cardiac remodelling after myocardial infarction (MI). It has been shown that the sphingosine 1-phosphate receptor 1 (S1pr1) was highly expressed in ECs and played an important role in maintaining endothelial functions. We thus hypothesized that the endothelial S1pr1 might be involved in post-MI cardiac remodelling.

METHODS AND RESULTS

Our study showed that the specific loss of endothelial S1pr1 exacerbated post-MI cardiac remodelling and worsened cardiac dysfunction. We found that the loss of endothelial S1pr1 significantly reduced Ly6clow macrophage accumulation, which is critical for the resolution of inflammation and cardiac healing following MI. The reduced reparative macrophages in post-MI myocardium contributed to the detrimental effects of endothelial S1pr1 deficiency on post-MI cardiac remodelling. Further investigations showed that the loss of endothelial S1pr1-reduced Ly6clow macrophage proliferation, while the pharmacological activation of S1pr1-enhanced Ly6clow macrophage proliferation, thereby ameliorated cardiac remodelling after MI. A mechanism study showed that S1P/S1pr1 activated the ERK signalling pathway and enhanced colony-stimulating factor 1 (CSF1) expression, which promoted Ly6clow macrophage proliferation in a cell-contact manner. The blockade of CSF1 signalling reversed the enhancing effect of S1pr1 activation on Ly6clow macrophage proliferation and worsened post-MI cardiac remodelling.

CONCLUSION

This study reveals that cardiac microvascular endothelium promotes reparative macrophage proliferation in injured hearts via the S1P/S1PR1/ERK/CSF1 pathway and thus ameliorates post-MI adverse cardiac remodelling.

Endothelial ERG alleviates cardiac fibrosis via blocking endothelin-1-dependent paracrine mechanism

Cardiac endothelium communicates closely with adjacent cardiac cells by multiple cytokines and plays critical roles in regulating fibroblasts proliferation, activation, and collagen synthesis during cardiac fibrosis. E26 transformation-specific (ETS)-related gene (ERG) belongs to the ETS transcriptional factor family and is required for endothelial cells (ECs) homeostasis and cardiac development. This study aims at investigating the potential role and molecular basis of ERG in fibrotic remodeling within the adult heart. We observed that ERG was abundant in murine hearts, especially in cardiac ECs, but decreased during cardiac fibrosis. ERG knockdown within murine hearts caused spontaneously cardiac fibrosis and dysfunction, accompanied by the activation of multiple Smad-dependent and independent pathways. However, the direct silence of ERG in cardiac fibroblasts did not affect the expression of fibrotic markers. Intriguingly, ERG knockdown in human umbilical vein endothelial cells (HUVECs) promoted the secretion of endothelin-1 (ET-1), which subsequently accelerated the proliferation, phenotypic transition, and collagen synthesis of cardiac fibroblasts in a paracrine manner. Suppressing ET-1 with either a neutralizing antibody or a receptor blocker abolished ERG knockdown-mediated deleterious effect in vivo and in vitro. This pro-fibrotic effect was also negated by RGD (Arg-Gly-Asp)-peptide magnetic nanoparticles target delivery of ET-1 small interfering RNA to ECs in mice. More importantly, we proved that endothelial ERG overexpression notably prevented pressure overload-induced cardiac fibrosis. Collectively, endothelial ERG alleviates cardiac fibrosis via blocking ET-1-dependent paracrine mechanism and it functions as a candidate for treating cardiac fibrosis. • ERG is abundant in murine hearts, especially in cardiac ECs, but decreased during fibrotic remodeling. • ERG knockdown causes spontaneously cardiac fibrosis and dysfunction. • ERG silence in HUVECs promotes the secretion of endothelin-1, which in turn activates cardiac fibroblasts in a paracrine manner. • Endothelial ERG overexpression prevents pressure overload-induced cardiac fibrosis.

Endothelial Klf2-Foxp1-TGFβ signal mediates the inhibitory effects of simvastatin on maladaptive cardiac remodeling

Aims: Pathological cardiac fibrosis and hypertrophy are common features of left ventricular remodeling that often progress to heart failure (HF). Endothelial cells (ECs) are the most abundant non-myocyte cells in adult mouse heart. Simvastatin, a strong inducer of Krüppel-like Factor 2 (Klf2) in ECs, ameliorates pressure overload induced maladaptive cardiac remodeling and dysfunction. This study aims to explore the detailed molecular mechanisms of the anti-remodeling effects of simvastatin.

Methods and Results: RGD-magnetic-nanoparticles were used to endothelial specific delivery of siRNA and we found absence of simvastatin's protective effect on pressure overload induced maladaptive cardiac remodeling and dysfunction after in vivo inhibition of EC-Klf2. Mechanism studies showed that EC-Klf2 inhibition reversed the simvastatin-mediated reduction of fibroblast proliferation and myofibroblast formation, as well as cardiomyocyte size and cardiac hypertrophic genes, which suggested that EC-Klf2 might mediate the anti-fibrotic and anti-hypertrophy effects of simvastatin. Similar effects were observed after Klf2 inhibition in cultured ECs. Moreover, Klf2 regulated its direct target gene TGFβ1 in ECs and mediated the protective effects of simvastatin, and inhibition of EC-Klf2 increased the expression of EC-TGFβ1 leading to simvastatin losing its protective effects. Also, EC-Klf2 was found to regulate EC-Foxp1 and loss of EC-Foxp1 attenuated the protective effects of simvastatin similar to EC-Klf2 inhibition.

Conclusions: We conclude that cardiac microvasculature ECs are important in the modulation of pressure overload induced maladaptive cardiac remodeling and dysfunction, and the endothelial Klf2-TGFβ1 or Klf2-Foxp1-TGFβ1 pathway mediates the preventive effects of simvastatin. This study demonstrates a novel mechanism of the non-cholesterol lowering effects of simvastatin for HF prevention.

FTY720 Reduces Endothelial Cell Apoptosis and Remodels Neurovascular Unit after Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. A sequence of pathological processes occurred when there is TBI. Previous studies showed that sphingosine-1-phosphate receptor 1 (S1PR1) played a critical role in inflammatory response in the brain after TBI. Thus, the present study was designed to evaluate the effects of the S1PR1 modulator FTY720 on neurovascular unit (NVU) after experimental TBI in mice. The weight-drop TBI method was used to induce TBI. Western blot (WB) was performed to determine the levels of SIPR1, claudin-5 and occludin at different time points. FTY720 was intraperitoneally administered to mice after TBI was induced. The terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) assay was used to assess endothelial cell apoptosis. Immunofluorescence and WB were performed to measure the expression of tight junction proteins: claudin-5 and occludin. Evans blue (EB) permeability assay and brain water content were applied to evaluate the blood-brain barrier (BBB) permeability and brain edema. Immunohistochemistry was performed to assess the activation of astrocytes and microglia. The results showed that FTY720 administration reduced endothelial cell apoptosis and improved BBB permeability. FTY720 also attenuated astrocytes and microglia activation. Furthermore, treatment with FTY720 not only improved neurological function, but also increased the survival rate of mice significantly. These findings suggest that FTY720 administration restored the structure of the NVU after experimental TBI by decreasing endothelial cell apoptosis and attenuating the activation of astrocytes. Moreover, FTY720 might reduce inflammation in the brain by reducing the activation of microglia in TBI mice.

Mechanisms of action of metformin and its regulatory effect on microRNAs related to angiogenesis

Angiogenesis is rapidly initiated in response to pathological conditions and is a key target for pharmaceutical intervention in various malignancies. Anti-angiogenic therapy has emerged as a potential and effective therapeutic strategy for treating cancer and cardiovascular-related diseases. Metformin, a first-line oral antidiabetic agent for type 2 diabetes mellitus (T2DM), not only reduces blood glucose levels and improves insulin sensitivity and exerts cardioprotective effects but also shows benefits against cancers, cardiovascular diseases, and other diverse diseases and regulates angiogenesis. MicroRNAs (miRNAs) are endogenous noncoding RNA molecules with a length of approximately 19-25 bases that are widely involved in controlling various human biological processes. A large number of miRNAs are involved in the regulation of cardiovascular cell function and angiogenesis, of which miR-21 not only regulates vascular cell proliferation, migration and apoptosis but also plays an important role in angiogenesis. The relationship between metformin and abnormal miRNA expression has gradually been revealed in the context of numerous diseases and has received increasing attention. This paper reviews the drug-target interactions and drug repositioning events of metformin that influences vascular cells and has benefits on angiogenesis-mediated effects. Furthermore, we use miR-21 as an example to explain the specific molecular mechanism underlying metformin-mediated regulation of the miRNA signaling pathway controlling angiogenesis and vascular protective effects. These findings may provide a new therapeutic target and theoretical basis for the clinical prevention and treatment of cardiovascular diseases.

MicroRNA-302/367 Cluster Impacts Host Antimicrobial Defense via Regulation of Mitophagic Response Against Pseudomonas aeruginosa Infection

Mitophagy has recently been implicated in bacterial infection but the underlying mechanism remains largely unknown. Here, we uncover a role of microRNA-302/367 cluster in regulating mitophagy and its associated host response against bacterial infection. We demonstrate that miR-302/367 cluster expression was significantly increased after Pseudomonas aeruginosa infection. Enhanced expression of miR-302/367 cluster accelerated the mitophagic response in macrophages, thus increasing clearance of invading P. aeruginosa by regulating production of reactive oxygen species (ROS), while application of miR-302/367 cluster inhibitors decreased bacterial clearance. Blocking mitophagy with siRNA against mitophagy receptor prohibitin 2 (PHB2) reduced the effect of miR-302/367 cluster on induction of mitophagy and its-associated P. aeruginosa elimination. In addition, we found that miR-302/367 cluster also increased bacterial clearance in mouse model. Mechanistically, we illustrate that miR-302/367 cluster binds to the 3′-untranslated region of nuclear factor kappa B (NF-κB), a negative regulator of mitophagy, accelerated the process of mitophagy by inhibiting NF-κB. Furthermore, inhibition of NF-κB in macrophages attenuated the ROS or cytokines production and may reduce cell injury by P. aeruginosa infection to maintain cellular homeostasis. Collectively, our findings elucidate that miR-302/367 cluster functions as potent regulators in mitophagy-mediated P. aeruginosa elimination and pinpoint an unexpected functional link between miRNAs and mitophagy.

Non-negligible factors in studying the ApoM-S1P axis using EA.hy926 cells

Background

The apolipoprotein M (ApoM)-sphingosine-1-phosphate (S1P) axis was recently identified, and research into its function has received increasing attention. However, there are some factors which might influence the results of studies into the function of the ApoM-S1P axis using the EA.hy926 cells. This study investigated related factors, including coagulation factor VIII (FVIII), ApoM, S1P receptor subtypes (S1PRs), C-myc-tagged, and His-tagged proteins in EA.hy926 cells, as well as the effects of ApoM overexpression on S1PRs.

Methods

The expression of FVIII, ApoM, S1PRs, C-myc, and His-tagged proteins in EA.hy926 cells was investigated through cellular immunofluorescence. EA.hy926 cells were infected with lentiviruses carrying (OE group) or lacking (NC group) the ApoM gene sequence. A stable cell line expressing ApoM was obtained, and the expression of ApoM mRNA was detected through single tube duplex fluorescence reverse transcription quantitative polymerase chain reaction (RT-qPCR). S1PRs expression was detected by RT-qPCR and Western blotting.

Results

The results showed that EA.hy926 cells expressed FVIII, ApoM, C-myc-tagged, and His-tagged proteins. Moreover, they highly expressed S1PR1, slightly expressed S1PR3, weakly expressed S1PR2, and did not express S1PR4 and S1PR5. ApoM overexpression significantly increased S1PR1 mRNA and protein expression but did not affect the expression of S1PR3. EA.hy926 cells expressed FVIII, suggesting the cell line possesses endothelial cell characteristics and could be used for in vitro studies of the ApoM-S1P axis.

Conclusions

EA.hy926 cell line is suitable for investigation of the ApoM-S1P axis in vitro. However, Since EA.hy926 cells expressed endogenous ApoM, C-myc and His tagged proteins, the exogenous recombinant ApoM should not be labeled with C-myc and His tags for distinguishing from endogenous ApoM. In addition, overexpression of ApoM should be considered to significantly increase the expression of S1PR1 when studying the APOM-S1P axis.

Hsa-miR-1908-3p Mediates the Self-Renewal and Apoptosis of Human Spermatogonial Stem Cells via Targeting KLF2

Spermatogenesis depends on precise epigenetic and genetic regulation of spermatogonial stem cells (SSCs). However, it remains largely unknown about the roles and mechanisms of small noncoding RNA in regulating the self-renewal and apoptosis of human SSCs. Notably, we have found that Homo sapiens-microRNA (hsa-miR)-1908-3p is expressed at a higher level in human spermatogonia than pachytene spermatocytes. MiR-1908-3p stimulated cell proliferation and DNA synthesis of the human SSC line. Allophycocyanin (APC) Annexin V and propidium iodide staining, determined by flow cytometric analysis and TUNEL assays, showed that miR-1908-3p inhibited early and late apoptosis of the human SSC line. Furthermore, Kruppel-like factor 2 (KLF2) was predicted and verified as the target of miR-1908-3p, and, significantly, KLF2 silencing resulted in the increase of proliferation and DNA synthesis, as well as reduction of apoptosis of the human SSC line. Moreover, KLF2 silencing ameliorated the decrease in the proliferation and DNA synthesis and the enhancement in the apoptosis of the human SSC line caused by miR-1908-3p inhibition. Collectively, these results implicate that miR-1908-3p stimulates the self-renewal and suppresses the apoptosis of human SSCs by targeting KLF2. This study thus provides a novel epigenetic regulatory mechanism underlying the fate determinations of human SSCs, and it offers new endogenous targets for treating male infertility.

Overexpression of miR-181a-5p inhibits retinal neovascularization through endocan and the ERK1/2 signaling pathway

Retinal neovascularization (RNV) is a common pathological feature of angiogenesis‐related retinopathy. Endocan inhibition has previously been reported to suppress RNV in oxygen‐induced retinopathy (OIR); however, its molecular mechanisms remain to be elucidated. Here, we investigated the role and mechanism of endocan in OIR. We established an OIR mouse model and detected aberrant endocan overexpression in OIR mouse retinas. Endocan inhibition through small interfering RNA or a neutralizing antibody inhibited vascular endothelial growth factor‐induced cell survival, cell proliferation, and tube formation in human retinal endothelial cells in vitro and reduced the RNV area in vivo. Using RNA sequencing, a luciferase reporter assay, and bioinformatics analyses, we identified endocan as a microRNA‐181a‐5p target gene. The antiangiogenic effect of miR‐181a‐5p on RNV was verified by intravitreal injection, and we showed that this involved the extracellular signal‐regulated protein kinases 1 and 2 (ERK1/2) signaling pathway. Collectively, our data demonstrate that miR‐181a‐5p/endocan regulates retinal angiogenesis through the ERK1/2 signaling pathway and might represent an attractive therapeutic strategy for RNV.

Psoralen Suppresses Cisplatin-Mediated Resistance and Induces Apoptosis of Gastric Adenocarcinoma by Disruption of the miR196a-HOXB7-HER2 Axis

Purpose

The present study aimed to investigate the impact of psoralen on miR-196a-5p expression and function, and to reveal the mechanism underlying miR-196a-5p-mediated inhibition and the reversal of cisplatin (DDP) resistance.

Methods

Serum samples were collected from 50 patients with gastric cancer (GC), and the association between miR-196a-5p expression and the response to chemotherapy was assessed. A DDP-resistant GC cell line was also established to determine the effects of miR-196a-5p and psoralen on DDP resistance. MGC803 cells were transfected with miR-196a-5p mimic and inhibitor vectors for the overexpression and downregulation of miR-196a-5p, respectively.

Results

Clinical data analysis showed that the lower expression levels of miR-196a-5p were significantly associated with chemoresistance in patients with GC. Upregulation of miR-196a-5p significantly enhanced the anti-proliferative effect, apoptosis and sensitivity to DDP by regulating the protein expression levels of HOXB7, HER2, Bcl-2 and G₁/S-specific cyclin-D1 (CCND1). Furthermore, psoralen reversed miR-196a-5p-induced DDP resistance and reduced the expression levels of HOXB7, HER2, Bcl-2 and CCND1.

Conclusion

miR-196a-5p may be a novel biomarker of chemotherapeutic success in patients with GC and may also influence the sensitivity of GC cells to DDP. Moreover, psoralen can increase chemotherapeutic sensitivity by upregulating miR-196a-5p and then downregulating HOXB7-HER2 signaling axis.

Potential sphingosine-1-phosphate-related therapeutic targets in the treatment of cerebral ischemia reperfusion injury

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that regulates lymphocyte trafficking, glial cell activation, vasoconstriction, endothelial barrier function, and neuronal death pathways in the brain. Research has increasingly implicated S1P in the pathology of cerebral ischemia reperfusion (IR) injury. As a high-affinity agonist of S1P receptor, fingolimod exhibits excellent neuroprotective effects against ischemic challenge both in vivo and in vitro. By summarizing recent progress on how S1P participates in the development of brain IR injury, this review identifies potential therapeutic targets for the treatment of brain IR injury.

Application of the microRNA-302/367 cluster in cancer therapy

As a novel class of noncoding RNAs, microRNAs (miRNAs) can effectively silence their target genes at the posttranscriptional level. Various biological processes, such as cell proliferation, differentiation, and motility, are regulated by miRNAs. In different diseases and different stages of disease, miRNAs have various expression patterns, which makes them candidate prognostic markers and therapeutic targets. Abnormal miRNA expression has been detected in numerous neoplastic diseases in humans, which indicates the potential role of miRNAs in tumorigenesis. Previous studies have indicated that miRNAs are involved in nearly the entire process of tumor development. MicroRNA‐302a, miR‐302b, miR‐302c, miR‐302d, and miR‐367 are members of the miR‐302/367 cluster that plays various biological roles in diverse neoplastic diseases by targeting different genes. These miRNAs have been implicated in several unique characteristics of cancer, including the evasion of growth suppressors, the sustained activation of proliferative signaling, the evasion of cell death and senescence, and the regulation of angiogenesis, invasion, and metastasis. This review provides a critical overview of miR‐302/367 cluster dysregulation and the subsequent effects in cancer and highlights the vast potential of members of this cluster as therapeutic targets and novel biomarkers.

Role of microRNAs in remodeling the tumor microenvironment (Review)

MicroRNAs (miRNAs) are short non-coding RNAs that are known to regulate gene expression at the post-transcriptional level. miRNA expression is often deregulated in several human cancers, affecting the communication between tumor stroma and tumor cells, among other functions. Understanding the role of miRNAs in the tumor microenvironment is crucial for fully elucidating the molecular mechanisms underlying tumor progression and exploring novel diagnostic biomarkers and therapeutic targets. The present review focused on the role of miRNAs in remodeling the tumor microenvironment, with an emphasis on their impact on tumor growth, metastasis and resistance to treatment, as well as their potential clinical applications.

Endothelial S1pr1 regulates pressure overload-induced cardiac remodelling through AKT-eNOS pathway

Cardiac vascular microenvironment is crucial for cardiac remodelling during the process of heart failure. Sphingosine 1‐phosphate (S1P) tightly regulates vascular homeostasis via its receptor, S1pr1. We therefore hypothesize that endothelial S1pr1 might be involved in pathological cardiac remodelling. In this study, heart failure was induced by transverse aortic constriction (TAC) operation. S1pr1 expression is significantly increased in microvascular endothelial cells (ECs) of post‐TAC hearts. Endothelial‐specific deletion of S1pr1 significantly aggravated cardiac dysfunction and deteriorated cardiac hypertrophy and fibrosis in myocardium. In vitro experiments demonstrated that S1P/S1pr1 praxis activated AKT/eNOS signalling pathway, leading to more production of nitric oxide (NO), which is an essential cardiac protective factor. Inhibition of AKT/eNOS pathway reversed the inhibitory effect of EC‐S1pr1‐overexpression on angiotensin II (AngII)‐induced cardiomyocyte (CM) hypertrophy, as well as on TGF‐β‐mediated cardiac fibroblast proliferation and transformation towards myofibroblasts. Finally, pharmacological activation of S1pr1 ameliorated TAC‐induced cardiac hypertrophy and fibrosis, leading to an improvement in cardiac function. Together, our results suggest that EC‐S1pr1 might prevent the development of pressure overload‐induced heart failure via AKT/eNOS pathway, and thus pharmacological activation of S1pr1 or EC‐targeting S1pr1‐AKT‐eNOS pathway could provide a future novel therapy to improve cardiac function during heart failure development.

Roles of sphingosine-1-phosphate signaling in cancer

The potent pleiotropic lipid mediator sphingosine-1-phosphate (S1P) participates in numerous cellular processes, including angiogenesis and cell survival, proliferation, and migration. It is formed by one of two sphingosine kinases (SphKs), SphK1 and SphK2. These enzymes largely exert their various biological and pathophysiological actions through one of five G protein-coupled receptors (S1PR1–5), with receptor activation setting in motion various signaling cascades. Considerable evidence has been accumulated on S1P signaling and its pathogenic roles in diseases, as well as on novel modulators of S1P signaling, such as SphK inhibitors and S1P agonists and antagonists. S1P and ceramide, composed of sphingosine and a fatty acid, are reciprocal cell fate regulators, and S1P signaling plays essential roles in several diseases, including inflammation, cancer, and autoimmune disorders. Thus, targeting of S1P signaling may be one way to block the pathogenesis and may be a therapeutic target in these conditions. Increasingly strong evidence indicates a role for the S1P signaling pathway in the progression of cancer and its effects. In the present review, we discuss recent progress in our understanding of S1P and its related proteins in cancer progression. Also described is the therapeutic potential of S1P receptors and their downstream signaling cascades as targets for cancer treatment.

Repression of TGF-β Signaling in Breast Cancer Cells by miR-302/367 Cluster

Objective

Epigenetic alterations of the malignantly transformed cells have increasingly been regarded as an important event in the carcinogenic development. Induction of some miRNAs such as miR-302/367 cluster has been shown to induce reprogramming of breast cancer cells and exert a tumor suppressive role by induction of mesenchymal to epithelial transition, apoptosis and a lower proliferation rate. Here, we aimed to investigate the impact of miR-302/367 overexpression on transforming growth factor-beta (TGF-β) signaling and how this may contribute to tumor suppressive effects of miR-302/367 cluster.

Materials and Methods

In this experimental study, MDA-MB-231 and SK-BR-3 breast cancer cells were cultured and transfected with miR-302/367 expressing lentivector. The impact of miR-302/367 overexpression on several mediators of TGF-β signaling and cell cycle was assessed by quantitative real-time polymerase chain reaction (qPCR) and flow cytometry.

Results

Ectopic expression of miR-302/367 cluster downregulated expression of some downstream elements of TGF-β pathway in MDA-MB-231 and SK-BR-3 breast cancer cell lines. Overexpression of miR-302/367 cluster inhibited proliferation of the breast cancer cells by suppressing the S-phase of cell cycle which was in accordance with inhibition of TGF-β pathway.

Conclusion

TGF-β signaling is one of the key pathways in tumor progression and a general suppression of TGF-β mediators by the pleiotropically acting miR-302/367 cluster may be one of the important reasons for its anti-tumor effects in breast cancer cells.

Endothelial Forkhead Box Transcription Factor P1 Regulates Pathological Cardiac Remodeling Through Transforming Growth Factor-β1-Endothelin-1 Signal Pathway

BACKGROUND

Pathological cardiac fibrosis and hypertrophy, the common features of left ventricular remodeling, often progress to heart failure. Forkhead box transcription factor P1 (Foxp1) in endothelial cells (ECs) has been shown to play an important role in heart development. However, the effect of EC-Foxp1 on pathological cardiac remodeling has not been well clarified. This study aims to determine the role of EC-Foxp1 in pathological cardiac remodeling and the underlying mechanisms.

METHODS

Foxp1 EC-specific loss-of-function and gain-of-function mice were generated, and an angiotensin II infusion or a transverse aortic constriction operation mouse model was used to study the cardiac remodeling mechanisms. Foxp1 downstream target gene transforming growth factor-β1 (TGF-β1) was confirmed by chromatin immunoprecipitation and luciferase assays. Finally, the effects of TGF-β1 blockade on EC-Foxp1 deletion-mediated profibrotic and prohypertrophic phenotypic changes were further confirmed by pharmacological inhibition, more specifically by RGD-peptide magnetic nanoparticle target delivery of TGF-β1-siRNA to ECs.

RESULTS

Foxp1 expression is significantly downregulated in cardiac ECs during angiotensin II-induced cardiac remodeling. EC-Foxp1 deletion results in severe cardiac remodeling, including more cardiac fibrosis with myofibroblast formation and extracellular matrix protein production, as well as decompensated cardiac hypertrophy and further exacerbation of cardiac dysfunction on angiotensin II infusion or transverse aortic constriction operation. In contrast, EC-Foxp1 gain of function protects against pathological cardiac remodeling and improves cardiac dysfunction. TGF-β1 signals are identified as Foxp1 direct target genes, and EC-Foxp1 deletion upregulates TGF-β1 signals to promote myofibroblast formation through fibroblast proliferation and transformation, resulting in severe cardiac fibrosis. Moreover, EC-Foxp1 deletion enhances TGF-β1-promoted endothelin-1 expression, which significantly increases cardiomyocyte size and reactivates cardiac fetal genes, leading to pathological cardiac hypertrophy. Correspondingly, these EC-Foxp1 deletion-mediated profibrotic and prohypertrophic phenotypic changes and cardiac dysfunction are normalized by the blockade of TGF-β1 signals through pharmacological inhibition and RGD-peptide magnetic nanoparticle target delivery of TGF-β1-siRNA to ECs.

CONCLUSIONS

EC-Foxp1 regulates the TGF-β1-endothelin-1 pathway to control pathological cardiac fibrosis and hypertrophy, resulting in cardiac dysfunction. Therefore, targeting the EC-Foxp1-TGF-β1-endothelin-1 pathway might provide a future novel therapy for heart failure.

MiR-30a regulates cancer cell response to chemotherapy through SNAI1/IRS1/AKT pathway

Despite gemcitabine being the leading chemotherapeutic drug for pancreatic cancer, many patients still relapse due to the drug resistance. We previously reported the molecular link between FKBP51 mediated AKT inhibition and gemcitabine response in pancreatic cancers. However, the upstream regulator of this pathway, especially the involvement of non-coding RNAs in gemcitabine response is still not clear. Here we delineated the miRNA expression profile and key signaling pathways associated with gemcitabine response. Furthermore, we confirmed that miR-30a, one node of this network, regulated cellular response to gemcitabine through SNAI1-IRS1-AKT pathway. MiR-30a directly targeted SNAI1, which activates AKT and ERK through regulating IRS1 in vitro and in vivo. Clinically, miR-30a is downregulated in pancreatic cancer tissue and associated with overall patient survival. We also identified miR-30a as an AKT-FOXO3a-regulated gene that forms a feedback loop. Together, these results demonstrate that miR-30a is an upstream regulator of the Akt pathway with a critical role in cancer etiology and chemoresistance.

Profiling changes in cortical astroglial cells following chronic stress

Recent studies have suggested that cortical astroglia play an important role in depressive-like behaviors. Potential astroglial contributions have been proposed based on their known neuroplastic functions, such as glutamate recycling and synaptic plasticity. However, the specific mechanisms by which astroglial cells may contribute or protect against a depressive phenotype remain unknown. To delineate astroglial changes that accompany depressive-like behavior, we used astroglial-specific bacTRAP mice exposed to chronic variable stress (CVS) and profiled the astroglial translatome using translating ribosome affinity purification (TRAP) in conjunction with RNAseq. As expected, CVS significantly increased anxiety- and depressive-like behaviors and corticosterone levels and decreased GFAP expression in astroglia, although this did not reflect a change in the total number of astroglial cells. TRAPseq results showed that CVS decreased genes associated with astroglial plasticity: RhoGTPases, growth factor signaling, and transcription regulation, and increased genes associated with the formation of extracellular matrices such as perineuronal nets (PNNs). PNNs inhibit neuroplasticity and astroglia contribute to the formation, organization, and maintenance of PNNs. To validate our TRAPseq findings, we showed an increase in PNNs following CVS. Degradation of PNNs in the prefrontal cortex of mice exposed to CVS reversed the CVS-induced behavioral phenotype in the forced swim test. These data lend further support to the neuroplasticity hypothesis of depressive behaviors and, in particular, extend this hypothesis beyond neuronal plasticity to include an overall decrease in genes associated with cortical astroglial plasticity following CVS. Further studies will be needed to assess the antidepressant potential of directly targeting astroglial cell function in models of depression.

Elevated Expression of miR302-367 in Endothelial Cells Inhibits Developmental Angiogenesis via CDC42/CCND1 Mediated Signaling Pathways

Rationale: Angiogenesis is critical for embryonic development and microRNAs fine-tune this process, but the underlying mechanisms remain incompletely understood.

Methods: Endothelial cell (EC) specific miR302-367 line was used as gain-of-function and anti-miRs as loss-of-function models to investigate the effects of miR302-367 on developmental angiogenesis with embryonic hindbrain vasculature as an in vivo model and fibrin gel beads and tube formation assay as in vitro models. Cell migration was evaluated by Boyden chamber and scratch wound healing assay and cell proliferation by cell count, MTT assay, Ki67 immunostaining and PI cell cycle analysis. RNA high-throughput sequencing identified miR-target genes confirmed by chromatin immunoprecipitation and 3'-UTR luciferase reporter assay, and finally target site blocker determined the pathway contributing significantly to the phenotype observed upon microRNA expression.

Results: Elevated EC miR302-367 expression reduced developmental angiogenesis, whereas it was enhanced by inhibition of miR302-367, possibly due to the intrinsic inhibitory effects on EC migration and proliferation. We identified Cdc42 as a direct target gene and elevated EC miR302-367 decreased total and active Cdc42, and further inhibited F-actin formation via the WASP and Klf2/Grb2/Pak1/LIM-kinase/Cofilin pathways. MiR302-367-mediated-Klf2 regulation of Grb2 for fine-tuning Pak1 activation contributing to the inhibited F-actin formation, and then the attenuation of EC migration. Moreover, miR302-367 directly down-regulated EC Ccnd1 and impaired cell proliferation via the Rb/E2F pathway.

Conclusion: miR302-367 regulation of endothelial Cdc42 and Ccnd1 signal pathways for EC migration and proliferation advances our understanding of developmental angiogenesis, and meanwhile provides a rationale for future interventions of pathological angiogenesis that shares many common features of physiological angiogenesis.

Apln-CreERT:mT/mG reporter mice as a tool for sprouting angiogenesis study

Background

Angiogenesis is defined as a new blood vessel sprouting from pre-existing vessels, and the sprouting angiogenesis is the start phase of angiogenesis, which is critical for both physiological and pathological processes, such as embryonic development, organ growth, wound healing, tumor growth, diabetic retinopathy and age-related macular degeneration. Better understanding of the mechanisms of sprout angiogenesis will provide a rationale for the treatments of these angiogenesis related diseases.

Methods

mT/mG tool mice are crossed with Apln-CreERT mice to generate Apln-CreERT: mT/mG mice, then we used neonatal retinal angiogenesis model to observe the angiogenic pattern of Apln-CreERT:mT/mG mice compared with Cdh5-CreERT:mT/mG mice. FACS analysis was used to sort eGFP and tdTomato endothelial cells (ECs) for measuring Apelin and Cdh5 expression. Retinal sprouting angiogenesis pattern was also observed at different neonatal time when induced by tamoxifen and at hypoxia condition, as well as in vivo tumor in real-time angiogenesis in a dorsal skinfold window chamber in Apln-CreERT:mT/mG mice.

Results

Apln-CreERT:mT/mG mice exhibited eGFP signal only in the sprouting angiogenesis, with less eGFP expression in the retinal “optic nerve” area than in that of Cdh5-CreERT: mT/mG mice, which might be due to relative mature vessels in the “optic nerve” area. The ECs sorted by FACS confirmed that the Apelin expression level was higher in eGFP ECs than tdTomato ECs of “optic nerve” area. Further we found that GFP-labeled sprouting angiogenesis decreased gradually following tamoxifen administration from P5-P7, but increased significantly during hypoxia in Apln-CreERT:mT/mG mice. At last, using Apln-CreERT:mT/mG mice we found tumor sprouting angiogenesis in dorsal skinfold, but not in the normal skinfold tissue.

Conclusions

Apln-CreERT:mT/mG mouse line is a useful tool to differentiate sprouting angiogenesis from whole blood vessels in the investigation of retinal and tumor sprouting angiogenesis in vivo.