Transforming growth factor β-regulated microRNA-29a promotes angiogenesis through targeting the phosphatase and tensin homolog in endothelium

MicroRNA-29 differentially mediates preeclampsia-dysregulated cellular responses to cytokines in female and male fetal endothelial cells

Preeclampsia (PE) differentially impairs female and male fetal endothelial cell function, which is associated with an increased risk of adult-onset cardiovascular disorders in children born to mothers with PE. However, the underlying mechanisms are poorly defined. We hypothesize that dysregulation of microRNA-29a-3p and 29c-3p (miR-29a/c-3p) in PE disturbs gene expression and cellular responses to cytokines in fetal endothelial cells in a fetal sex-dependent manner. RT-qPCR analysis of miR-29a/c-3p was performed on female and male unpassaged (P0) human umbilical vein endothelial cells (HUVECs) from normotensive (NT) pregnancies and PE. Bioinformatic analysis of an RNA-seq dataset was performed to identify PE-dysregulated miR-29a/c-3p target genes in female and male P0-HUVECs. Gain- and loss-of-function assays were conducted to determine the effects of miR-29a/c-3p on endothelial monolayer integrity and proliferation in response to transforming growth factor-β1 (TGFβ1) and tumour necrosis factor-α (TNFα) in NT and PE HUVECs at passage 1. We observed that PE downregulated miR-29a/c-3p in male and female P0-HUVECs. PE dysregulated significantly more miR-29a/c-3p target genes in female vs. male P0-HUVECs. Many of these PE-differentially dysregulated miR-29a/c-3p target genes are associated with critical cardiovascular diseases and endothelial function. We further demonstrated that miR-29a/c-3p knockdown specifically recovered the PE-abolished TGFβ1-induced strengthening of endothelial monolayer integrity in female HUVECs, while miR-29a/c-3p overexpression specifically enhanced the TNFα-promoted cell proliferation in male PE HUVECs. In conclusion, PE downregulates miR-29a/c-3p expression and differentially dysregulates miR-29a/c-3p target genes associated with cardiovascular diseases and endothelial function in female and male fetal endothelial cells, possibly contributing to the fetal sex-specific endothelial dysfunction observed in PE. KEY POINTS: Preeclampsia differentially impairs female and male fetal endothelial cell function in responses to cytokines. Pro-inflammatory cytokines are elevated in maternal circulation during pregnancy in preeclampsia. MicroRNAs are critical regulators of endothelial cell function during pregnancy. We have previously reported that preeclampsia downregulated microRNA-29a-3p and 29c-3p (miR-29a/c-3p) in primary fetal endothelial cells. However, it is unknown if PE differentially dysregulates the expression of miR-29a/c-3p in female and male fetal endothelial cells. We show that preeclampsia downregulates miR-29a/c-3p in male and female HUVECs and preeclampsia dysregulates cardiovascular disease- and endothelial function-associated miR-29a/c-3p target genes in HUVECs in a fetal sex-specific manner. MiR-29a/c-3p differentially mediate cell responses to cytokines in female and male fetal endothelial cells from preeclampsia. We have revealed fetal sex-specific dysregulation of miR-29a/c-3p target genes in fetal endothelial cells from preeclampsia. This differential dysregulation may contribute to fetal sex-specific endothelial dysfunction in offspring born to preeclamptic mothers.

MicroRNA-29 Differentially Mediates Preeclampsia-Dysregulated Cellular Responses to Cytokines in Female and Male Fetal Endothelial Cells

Introduction

Preeclampsia (PE) differentially impairs female and male fetal endothelial cell function which is associated with the increased risks of adult-onset cardiovascular disorders in children born to mothers with PE. However, the underlying mechanisms are poorly defined. We hypothesize that dysregulation of microRNA-29a-3p and 29c-3p (miR-29a/c-3p) in PE disturbs gene expression and cellular responses to cytokines in fetal endothelial cells in a fetal sex-dependent manner.

Methods

RT-qPCR analysis of miR-29a/c-3p was performed on female and male unpassaged (P0) human umbilical vein endothelial cells (HUVECs) from normotensive (NT) and PE pregnancies. Bioinformatic analysis of an RNAseq dataset was performed to identify PE-dysregulated miR-29a/c-3p target genes in female and male P0-HUVECs. Gain- and loss-of-function assays were conducted to determine the effects of miR-29a/c-3p on endothelial monolayer integrity and proliferation in response to TGFβ1 and TNFα in NT and PE HUVECs at passage 1.

Results

PE downregulated miR-29a/c-3p in male, but not female P0-HUVECs. PE dysregulated significantly more miR-29a/c-3p target genes in female vs. male P0-HUVECs. Many of these PE-differentially dysregulated miR-29a/c-3p target genes are associated with critical cardiovascular diseases and endothelial functions. We further demonstrated that miR-29a/c-3p knockdown specifically recovered the PE-abolished TGFβ1-induced strengthening of endothelial monolayer integrity in female HUVECs, while miR-29a/c-3p overexpression specifically enhanced the TNFα-promoted cell proliferation in male PE HUVECs.

Conclusions

PE differentially dysregulates miR-29a/c-3p and their target genes associated with cardiovascular diseases- and endothelial function in female and male fetal endothelial cells, possibly contributing to the fetal sex-specific endothelial dysfunction observed in PE.

The Role of microRNA in the Development, Diagnosis, and Treatment of Cardiovascular Disease: Recent Developments

Since their discovery in 1993, microRNAs (miRNAs) have emerged as important regulators of many crucial cellular processes, and their dysregulation have been shown to contribute to multiple pathologic conditions, including cardiovascular disease (CVD). miRNAs have been found to regulate the expression of various genes involved in cardiac development and function and in the development and progression of CVD. Many miRNAs are master regulators fine-tuning the expression of multiple, often interrelated, genes involved in inflammation, apoptosis, fibrosis, senescence, and other processes crucial for the development of different forms of CVD. This article presents a review of recent developments in our understanding of the role of miRNAs in the development of CVD and surveys their potential applicability as therapeutic targets and biomarkers to facilitate CVD diagnosis, prognosis, and treatment. There are currently multiple potential miRNA-based therapeutic agents in different stages of development, which can be grouped into two classes: miRNA mimics (replicating the sequence and activity of their corresponding miRNAs) and antagomiRs (antisense inhibitors of specific miRNAs). However, in spite of promising preliminary data and our ever-increasing knowledge about the mechanisms of action of specific miRNAs, miRNA-based therapeutics and biomarkers have yet to be approved for clinical applications. SIGNIFICANCE STATEMENT: Over the last few years microRNAs have emerged as crucial, specific regulators of the cardiovascular system and in the development of cardiovascular disease, by posttranscriptional regulation of their target genes. The minireview presents the most recent developments in this area of research, including the progress in diagnostic and therapeutic applications of microRNAs. microRNAs seem very promising candidates for biomarkers and therapeutic agents, although some challenges, such as efficient delivery and unwanted effects, need to be resolved.

Roles of TGF-β in cancer hallmarks and emerging onco-therapeutic design

Transforming growth factor-beta (TGF-β) is a double-edged sword in cancer treatment because of its pivotal yet complex and roles played during cancer initiation/development. Current anti-cancer strategies involving TGF-β largely view TGF-β as an onco-therapeutic target that not only substantially hinders its full utilisation for cancer control, but also considerably restricts innovations in this field. Thereby, how to take advantages of therapeutically favourable properties of TGF-β for cancer management represents an interesting and less investigated problem. Here, by categorising cancer hallmarks into four critical transition events and one enabling characteristic controlling cancer initiation and progression, and delineating TGF-β complexities according to these cancer traits, we identify the suppressive role of TGF-β in tumour initiation and early-stage progression and its promotive functionalities in cancer metastasis as well as other cancer hallmarks. We also propose the feasibility and possible scenarios of combining cold atmospheric plasma (CAP) with onco-therapeutics utilising TGF-β for cancer control given the intrinsic properties of CAP against cancer hallmarks.

Transforming growth factor-β in tumour development

Transforming growth factor-β (TGFβ) is a ubiquitous cytokine essential for embryonic development and postnatal tissue homeostasis. TGFβ signalling regulates several biological processes including cell growth, proliferation, apoptosis, immune function, and tissue repair following injury. Aberrant TGFβ signalling has been implicated in tumour progression and metastasis. Tumour cells, in conjunction with their microenvironment, may augment tumourigenesis using TGFβ to induce epithelial-mesenchymal transition, angiogenesis, lymphangiogenesis, immune suppression, and autophagy. Therapies that target TGFβ synthesis, TGFβ-TGFβ receptor complexes or TGFβ receptor kinase activity have proven successful in tissue culture and in animal models, yet, due to limited understanding of TGFβ biology, the outcomes of clinical trials are poor. Here, we review TGFβ signalling pathways, the biology of TGFβ during tumourigenesis, and how protein quality control pathways contribute to the tumour-promoting outcomes of TGFβ signalling.

MicroRNA-29a Manifests Multifaceted Features to Intensify Radiosensitivity, Escalate Apoptosis, and Revoke Cell Migration for Palliating Radioresistance-Enhanced Cervical Cancer Progression

Radioresistance remains a major clinical challenge in cervical cancer therapy and results in tumor relapse and metastasis. Nevertheless, the detailed mechanisms are still largely enigmatic. This study was conducted to elucidate the prospective impacts of microRNA-29a (miR-29a) on the modulation of radioresistance-associated cervical cancer progression. Herein, we established two pairs of parental wild-type (WT) and radioresistant (RR) cervical cancer cells (CaSki and C33A), and we found that constant suppressed miR-29a, but not miR-29b/c, was exhibited in RR-clones that underwent a dose of 6-Gy radiation treatment. Remarkably, radioresistant clones displayed low radiosensitivity, and the reduced apoptosis rate resulted in augmented surviving fractions, measured by the clonogenic survival curve assay and the Annexin V/Propidium Iodide apoptosis assay, respectively. Overexpression of miR-29a effectively intensified the radiosensitivity and triggered the cell apoptosis in RR-clones. In contrast, suppressed miR-29a modestly abridged the radiosensitivity and abolished the cell apoptosis in WT-clones. Hence, ectopically introduced miR-29a into RR-clones notably attenuated the wound-healing rate and cell migration, whereas reduced miR-29a aggravated cell mobilities of WT-clones estimated via the in vitro wound-healing assay and time-lapse recording assay. Notably, we further established the in vivo short-term lung locomotion metastasis model in BALB/c nude mice, and we found that increased lung localization was shown after tail-vein injection of RR-CaSki cells compared to those of WT-CaSki cells. Amplified miR-29a significantly eliminated the radioresistance-enhanced lung locomotion. Our data provide evidence suggesting that miR-29a is a promising microRNA signature in radioresistance of cervical cancer cells and displays multifaceted innovative roles involved in anti-radioresistance, escalated apoptosis, and anti-cell migration/metastasis. Amalgamation of a nucleoid-based strategy (miR-29a) together with conventional radiotherapy may be an innovative and eminent strategy to intensify the radiosensitivity and further protect against the subsequent radioresistance and the potential metastasis in cervical cancer treatment.

Microvascular Experimentation in the Chick Chorioallantoic Membrane as a Model for Screening Angiogenic Agents including from Gene-Modified Cells

The chick chorioallantoic membrane (CAM) assay model of angiogenesis has been highlighted as a relatively quick, low cost and effective model for the study of pro-angiogenic and anti-angiogenic factors. The chick CAM is a highly vascularised extraembryonic membrane which functions for gas exchange, nutrient exchange and waste removal for the growing chick embryo. It is beneficial as it can function as a treatment screening tool, which bridges the gap between cell based in vitro studies and in vivo animal experimentation. In this review, we explore the benefits and drawbacks of the CAM assay to study microcirculation, by the investigation of each distinct stage of the CAM assay procedure, including cultivation techniques, treatment applications and methods of determining an angiogenic response using this assay. We detail the angiogenic effect of treatments, including drugs, metabolites, genes and cells used in conjunction with the CAM assay, while also highlighting the testing of genetically modified cells. We also present a detailed exploration of the advantages and limitations of different CAM analysis techniques, including visual assessment, histological and molecular analysis along with vascular casting methods and live blood flow observations.

The Role of TGF-β Signaling Pathways in Cancer and Its Potential as a Therapeutic Target

The transforming growth factor-β (TGF-β) signaling pathway mediates various biological functions, and its dysregulation is closely related to the occurrence of malignant tumors. However, the role of TGF-β signaling in tumorigenesis and development is complex and contradictory. On the one hand, TGF-β signaling can exert antitumor effects by inhibiting proliferation or inducing apoptosis of cancer cells. On the other hand, TGF-β signaling may mediate oncogene effects by promoting metastasis, angiogenesis, and immune escape. This review summarizes the recent findings on molecular mechanisms of TGF-β signaling. Specifically, this review evaluates TGF-β's therapeutic potential as a target by the following perspectives: ligands, receptors, and downstream signaling. We hope this review can trigger new ideas to improve the current clinical strategies to treat tumors related to the TGF-β signaling pathway.

A BMPR2/YY1 Signaling Axis Is Required for Human Cytomegalovirus Latency in Undifferentiated Myeloid Cells

Human cytomegalovirus (HCMV) presents a major health burden in the immunocompromised and in stem cell transplant medicine. A lack of understanding about the mechanisms of HCMV latency in undifferentiated CD34⁺ stem cells, and how latency is broken for the virus to enter the lytic phase of its infective cycle, has hampered the development of essential therapeutics. Using a human induced pluripotent stem cell (iPSC) model of HCMV latency and patient-derived myeloid cell progenitors, we demonstrate that bone morphogenetic protein receptor type 2 (BMPR2) is necessary for HCMV latency. In addition, we define a crucial role for the transcription factor Yin Yang 1 (YY1) in HCMV latency; high levels of YY1 are maintained in latently infected cells as a result of BMPR2 signaling through the SMAD4/SMAD6 axis. Activation of SMAD4/6, through BMPR2, inhibits TGFbeta receptor signaling, which leads to the degradation of YY1 via induction of a cellular microRNA (miRNA), hsa-miR-29a. Pharmacological targeting of BMPR2 in progenitor cells results in the degradation of YY1 and an inability to maintain latency and renders cells susceptible to T cell killing. These data argue that BMPR2 plays a role in HCMV latency and is a new potential therapeutic target for maintaining or disrupting HCMV latency in myeloid progenitors.

CircRNA-Mediated Regulation of Angiogenesis: A New Chapter in Cancer Biology

Angiogenesis is necessary for carcinoma progression and is regulated by a variety of pro- and anti-angiogenesis factors. CircRNAs are RNA molecules that do not have a 5'-cap or a 3'-polyA tail and are involved in a variety of biological functions. While circRNA-mediated regulation of tumor angiogenesis has received much attention, the detailed biological regulatory mechanism remains unclear. In this review, we investigated circRNAs in tumor angiogenesis from multiple perspectives, including its upstream and downstream factors. We believe that circRNAs have natural advantages and great potential for the diagnosis and treatment of tumors, which deserves further exploration.

Upregulation of miR-29a suppressed the migration and invasion of trophoblasts by directly targeting LOXL2 in preeclampsia

OBJECTIVE

Preeclampsia is a pregnancy-specific disorder that is a major cause of maternal and foetal morbidity and mortality, with a prevalence of 6-8% of pregnancies. Although the downregulation of lysyl oxidase (LOX) and LOX-like protein 2 (LOXL2), which leads to reduced trophoblast cell migration and invasion through activation of the TGF-β1/Smad3/collagen pathway, is relevant to preeclampsia, the mechanisms regulating differences in the gene expression of LOX and LOXL2 in placentas are not yet understood. This study aimed to investigate the mechanisms regulating differences in the gene expression of LOX and LOXL2 in placentas.

METHODS

The expression of miRNAs, LOX and LOXL2 in preeclamptic placentas and control placentas was analysed by qPCR. Localisation of miR29a and LOXL2 in preeclamptic placentas was performed by RNA-Fluorescence in-situ hybridization assay. The direct regulation of LOXL2 by miR-29a was assessed by dual-luciferase reporter assays in human extravillous trophoblast cells (HTR8/SVneo). Cell migration and invasion were evaluated by Transwell assays in HTR8/SVneo cells.

RESULTS

miR-29a expression was upregulated in preeclamptic placentas and negatively correlated with LOXL2 mRNA expression levels. RNA-Fluorescence in-situ hybridization assay revealed a clear overlap between miR-29a and LOXL2 in the placentas of preeclampic women. LOXL2 was a direct target gene of miR-29a, as confirmed by a dual-luciferase reporter assay in HTR8/SVneo trophoblast cells. miR-29a suppressed HTR8/SVneo trophoblast cell migration and invasion. LOXL2 overexpression reversed the inhibitory effects of miR-29a on HTR8/SVneo trophoblast cell migration and invasion.

CONCLUSION

Our results suggest that the upregulation of miR-29a suppresses the migration and invasion of HTR8/SVneo trophoblast cells by directly targeting LOXL2 in preeclampsia.

MicroRNA-128 Confers Anti-Endothelial Adhesion and Anti-Migration Properties to Counteract Highly Metastatic Cervical Cancer Cells' Migration in a Parallel-Plate Flow Chamber

Despite the distant metastasis of cervical cancer cells being a prominent cause of mortality, neither the metastasis capacity nor the in vitro conditions mimicking adhesion of cervical cancer cells to endothelial cells have been fully elucidated. Circulating metastatic cancer cells undergo transendothelial migration and invade normal organs in distant metastasis; however, the putative molecular mechanism remains largely uncertain. In this study, we describe the use of an in vitro parallel-plate flow chamber to simulate the dynamic circulation stress on cervical cancer cells and elucidate their vascular adhesion and metastasis. We isolate the viable and shear stress-resistant (SSR) cervical cancer cells for mechanistic studies. Remarkably, the identified SSR-HeLa and SSR-CaSki exhibited high in vitro adhesive and metastatic activities. Hence, a consistently suppressed miR-128 level was revealed in SSR cell clones compared to those of parental wild-type (WT) cells. Overexpressed miR-128 attenuated SSR-HeLa cells’ adherence to human umbilical cord vein endothelial cells (HUVECs); in contrast, suppressed miR-128 efficiently augmented the static adhesion capacity in WT-HeLa and WT-CaSki cells. Hence, amplified miR-128 modestly abolished in vitro SSR-augmented HeLa and CaSki cell movement, whereas reduced miR-128 aggravated the migration speed in a time-lapse recording assay in WT groups. Consistently, the force expression of miR-128 alleviated the SSR-enhanced HeLa and CaSki cell mobility in a wound healing assay. Notably, miR-128 mediated SSR-enhanced HeLa and CaSki cells’ adhesion and metastasis through suppressed ITGA5, ITGB5, sLex, CEACAM-6, MMP9, and MMP23 transcript levels. Our data provide evidence suggesting that miR-128 is a promising microRNA that prevented endothelial cells’ adhesion and transendothelial migration to contribute to the SSR-enhanced adhesion and metastasis progression under a parallel-plate flow chamber system. This indicates that the nucleoid-based miR-128 strategy may be an attractive therapeutic strategy to eliminate tumor cells resistant to circulation shear flow, prevent vascular adhesion, and preclude subsequent transendothelial metastasis.

miR-29 Sustains B Cell Survival and Controls Terminal Differentiation via Regulation of PI3K Signaling

The phosphatidylinositol 3-kinase (PI3K) signaling cascade downstream of the B cell receptor (BCR) signalosome is essential for B cell maturation. Proper signaling strength is maintained through the PI3K negative regulator phosphatase and tensin homolog (PTEN). Although a role for microRNA (miRNA)-dependent control of the PTEN-PI3K axis has been described, the contribution of individual miRNAs to the regulation of this crucial signaling modality in mature B lymphocytes remains to be elucidated. Our analyses reveal that ablation of miR-29 specifically in B lymphocytes results in an increase in PTEN expression and dampening of the PI3K pathway in mature B cells. This dysregulation has a profound impact on the survival of B lymphocytes and results in increased class switch recombination and decreased plasma cell differentiation. Furthermore, we demonstrate that ablation of one copy of Pten is sufficient to ameliorate the phenotypes associated with miR-29 loss. Our data suggest a critical role for the miR-29-PTEN-PI3K regulatory axis in mature B lymphocytes.

Vascular Inflammation Is a Risk Factor Associated with Brain Atrophy and Disease Severity in Parkinson's Disease: A Case-Control Study

Introduction

Systemic inflammation with elevated oxidative stress causing neuroinflammation is considered a major factor in the pathogenesis of Parkinson's disease (PD). The interface between systemic circulation and the brain parenchyma is the blood-brain barrier (BBB), which also plays a role in maintaining neurovascular homeostasis. Vascular cell adhesion molecule-1 (VCAM-1) and microRNAs (miRNAs) regulate brain vessel endothelial function, neoangiogenesis, and, in turn, neuronal homeostasis regulation, such that their dysregulation can result in neurodegeneration, such as gray matter atrophy, in PD.

Objective

Our aim was to evaluate the associations among specific levels of gray matter atrophy, peripheral vascular adhesion molecules, miRNAs, and clinical disease severity in order to achieve a clearer understanding of PD pathogenesis.

Methods

Blood samples were collected from 33 patients with PD and 27 healthy volunteers, and the levels of VCAM-1 and several miRNAs in those samples were measured. Voxel-based morphometry (VBM) analysis was performed using 3 T magnetic resonance imaging (MRI) and SPM (Statistical Parametric Mapping software program). The associations among the vascular parameter, miRNAs, gray matter volume, and clinical disease severity measurements were evaluated by partial correlation analysis.

Results

The levels of VCAM-1, miRNA-22, and miRNA-29a expression were significantly elevated in the PD patients. The gray matter volume atrophy in the left parahippocampus, bilateral posterior cingulate gyrus, fusiform gyrus, left temporal gyrus, and cerebellum was significantly correlated with increased clinical disease severity, the upregulation of miRNA levels, and increased vascular inflammation.

Conclusion

Patients with PD seem to have abnormal levels of vascular inflammatory markers and miRNAs in the peripheral circulation, and these levels are correlated with specific brain volume changes. This study reinforces the associations among peripheral inflammation, the BBB interface, and gray matter atrophy in PD and further demonstrates that BBB dysfunction with neurovascular impairment may play an important role in PD progression.

Severe obstructive sleep apnea is associated with circulating microRNAs related to heart failure, myocardial ischemia, and cancer proliferation

PURPOSE

Obstructive sleep apnea (OSA) is associated with multiple comorbid conditions including cardiovascular diseases and cancer. There is a growing interest in exploring biomarkers to understand the related mechanisms and improve the risk stratification of OSA. Circulating microRNAs (miRNAs) are single noncoding strands of nearly 22 nucleotides that posttranscriptionally regulate target gene expression. Our aim was to identify miRNA profiles associated with OSA.

METHODS

We studied 48 male subjects, mostly Caucasian (63%) and overweight, divided by polysomnography into the no OSA control group (n = 6), mild OSA group (n = 12), moderate OSA group (n = 15), and severe OSA group (n = 15). The study groups were matched for age, body mass index (BMI), and body fat composition. miRNA profiles were measured from peripheral whole blood using two steps: (1) microarray analysis comprising more than 2500 miRNAs in a subsample of 12 subjects (three from each group); and (2) validation phase using real-time quantitative polymerase chain reaction (RTqPCR).

RESULTS

The microarray assessment identified 21 differentially expressed miRNAs among the groups. The RT-qPCR assessment showed that miR-1254 and miR-320e presented a gradual increase in expression parallel to OSA severity. Linear regression analysis showed that severe OSA was independently associated with miR-1254 (ß = 68.4; EP = 29.8; p = 0.02) and miR-320e (ß = 76.1; EP = 31.3; p = 0.02).

CONCLUSION

Severe OSA is independently associated with miRNAs that are involved in heart failure (miR-1254), myocardial ischemia/reperfusion (miR-320e), and cell proliferation in some cancer types (miR-1254 and miR-320e). Future investigations addressing whether these miRs may provide prognostic information in OSA are needed.

MicroRNA-29a Exhibited Pro-Angiogenic and Anti-Fibrotic Features to Intensify Human Umbilical Cord Mesenchymal Stem Cells-Renovated Perfusion Recovery and Preventing against Fibrosis from Skeletal Muscle Ischemic Injury

This study was conducted to elucidate whether microRNA-29a (miR-29a) and/or together with transplantation of mesenchymal stem cells isolated from umbilical cord Wharton’s jelly (uMSCs) could aid in skeletal muscle healing and putative molecular mechanisms. We established a skeletal muscle ischemic injury model by injection of a myotoxin bupivacaine (BPVC) into gastrocnemius muscle of C57BL/6 mice. Throughout the angiogenic and fibrotic phases of muscle healing, miR-29a was considerably downregulated in BPVC-injured gastrocnemius muscle. Overexpressed miR-29a efficaciously promoted human umbilical vein endothelial cells proliferation and capillary-like tube formation in vitro, crucial steps for neoangiogenesis, whereas knockdown of miR-29a notably suppressed those endothelial functions. Remarkably, overexpressed miR-29a profitably elicited limbic flow perfusion and estimated by Laser Dopple. MicroRNA-29a motivated perfusion recovery through abolishing the tissue inhibitor of metalloproteinase (TIMP)-2, led great numbers of pro-angiogenic matrix metalloproteinases (MMPs) to be liberated from bondage of TIMP, thus reinforced vascular development. Furthermore, engrafted uMSCs also illustrated comparable effect to restore the flow perfusion and augmented vascular endothelial growth factors-A, -B, and -C expression. Notably, the combination of miR29a and the uMSCs treatments revealed the utmost renovation of limbic flow perfusion. Amplified miR-29a also adequately diminished the collagen deposition and suppressed broad-wide miR-29a targeted extracellular matrix components expression. Consistently, miR-29a administration intensified the relevance of uMSCs to abridge BPVC-aggravated fibrosis. Our data support that miR-29a is a promising pro-angiogenic and anti-fibrotic microRNA which delivers numerous advantages to endorse angiogenesis, perfusion recovery, and protect against fibrosis post injury. Amalgamation of nucleic acid-based strategy (miR-29a) together with the stem cell-based strategy (uMSCs) may be an innovative and eminent strategy to accelerate the healing process post skeletal muscle injury.

Colorectal cancer cells differentially impact migration and microRNA expression in endothelial cells

Angiogenesis is an essential step in cancer progression and metastasis. Changes in the microRNA (miRNA or miR) expression profiles of endothelial cells (ECs) elicited by cancer cells promote angiogenesis. Vascular endothelial growth factor (VEGF), a key pro-angiogenic factor, influences miRNA expression in ECs; however, the exact role that VEGF serves in miRNA regulation during angiogenesis is poorly defined. The present study aimed to demonstrate the differential angiogenic effects on human umbilical vein endothelial cells (HUVECs) of five different colorectal cancer (CRC) cell lines by in vitro HUVEC migration and angiogenesis assays in response to CRC-conditioned medium (CM). Among the tested CMs, LoVo was the most effective cell line in eliciting HUVEC angiogenic phenotypes, at least partially due to its high VEGF level. It was also observed that pro-angiogenesis-regulatory miRNAs (angio-miRNA) miR-296, miR-132, miR-105 and miR-200 were upregulated in the VEGF-rich LoVo CM compared with the VEGF-scarce SW620 CM. In addition, treatment with VEGF receptor 2 inhibitor downregulated the pro-angio-miRNAs, with the exception of miR-132, suggesting that VEGF, as well as additional signaling, is required for angio-miRNA expression. Quantitative analyses on pro-angio-miRNA target expression suggested that independent pathways may be involved in the regulation of their expression. Overall, the data from the present study indicated that multiple paracrine factors, including VEGF secreted by CRCs, effectively modulated angio-miRNA expression, thus impacting their target expression and the angiogenic phenotypes of HUVECs.

Transforming growth factor β1 alters the 3'-UTR of mRNA to promote lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by the pathological remodeling of air sacs as a result of excessive accumulation of extracellular matrix (ECM) proteins, but the mechanism governing the robust protein expression is poorly understood. Our recent findings demonstrate that alternative polyadenylation (APA) caused by NUDT21 reduction is important for the increased expression of fibrotic mediators and ECM proteins in lung fibroblasts by shortening the 3'-untranslated regions (3'-UTRs) of mRNAs and stabilizing their transcripts, therefore activating pathological signaling pathways. Despite the importance of NUDT21 reduction in the regulation of fibrosis, the underlying mechanisms for the depletion are unknown. We demonstrate here that NUDT21 is depleted by TGFβ1. We found that miR203, which is increased in IPF, was induced by TGFβ1 to target the NUDT21 3'-UTR, thus depleting NUDT21 in human and mouse lung fibroblasts. TGFβ1-mediated NUDT21 reduction was attenuated by the miR203 inhibitor antagomiR203 in fibroblasts. TGFβ1 transgenic mice revealed that TGFβ1 down-regulates NUDT21 in fibroblasts in vivo Furthermore, TGFβ1 promoted differential APA of fibrotic genes, including FGF14, RICTOR, TMOD2, and UCP5, in association with increased protein expression. This unique differential APA signature was also observed in IPF fibroblasts. Altogether, our results identified TGFβ1 as an APA regulator through NUDT21 depletion amplifying pulmonary fibrosis.

HiPS-Cardiac Trilineage Cell Generation and Transplantation: a Novel Therapy for Myocardial Infarction

Despite primary percutaneous coronary intervention (PPCI) and the availability of optimal medications, including dual antiplatelet therapy (DAPT), most patients still experience major adverse cardiovascular events (MACEs) due to frequent recurrence of thrombotic complications and myocardial infarction (MI). MI occurs secondary to a massive loss of endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and cardiomyocytes (CMs). The adult cardiovascular system gradually loses the ability to spontaneously and regularly regenerate ECs, VSMCs, and CMs. However, human cells can be induced by cytokines and growth factors to regenerate human-induced pluripotent stem cells (hiPSCs), which progress to produce cardiac trilineage cells (CTCs) such as ECs, VSMCs, and CMs, replacing lost cells and inducing myocardial repair. Nevertheless, the processes and pathways involved in hiPSC-CTC generation and their potential therapeutic effects remain unknown. Herein, we provide evidence of in vitro CTC generation, the pathways involved, in vivo transplantation, and its therapeutic effect, which may provide novel targets in regenerative medicine for the treatment of cardiovascular diseases (CVDs).

Antiangiogenic Effect of Alkaloids

Alkaloids are among the natural phytochemicals contained in functional foods and nutraceuticals and have been suggested for the prevention and/or management of oxidative stress and inflammation-mediated diseases. In this review, we aimed to describe the effects of alkaloids in angiogenesis, the process playing a crucial role in tumor growth and invasion, whereby new vessels form. Antiangiogenic compounds including herbal ingredients, nonherbal alkaloids, and microRNAs can be used for the control and treatment of cancers. Several lines of evidence indicate that alkaloid-rich plants have several interesting features that effectively inhibit angiogenesis. In this review, we present valuable data on commonly used alkaloid substances as potential angiogenic inhibitors. Different herbal and nonherbal ingredients, introduced as antiangiogenesis agents, and their role in angiogenesis-dependent diseases are reviewed. Studies indicate that angiogenesis suppression is exerted through several mechanisms; however, further investigations are required to elucidate their precise molecular and cellular mechanisms, as well as potential side effects.

MicroRNAs in the cornea: Role and implications for treatment of corneal neovascularization

With no safe and efficient approved therapy available for treating corneal neovascularization, the search for alternative and effective treatments is of great importance. Since the discovery of miRNAs as key regulators of gene expression, knowledge of their function in the eye has expanded continuously, facilitated by high throughput genomic tools such as microarrays and RNA sequencing. Recently, reports have emerged implicating miRNAs in pathological and developmental angiogenesis. This has led to the idea of targeting these regulatory molecules as a therapeutic approach for treating corneal neovascularization. With the growing volume of data generated from high throughput tools applied to study corneal neovascularization, we provide here a focused review of the known miRNAs related to corneal neovascularization, while presenting new experimental data and insights for future research and therapy development.

LncRNA MALAT1 up-regulates VEGF-A and ANGPT2 to promote angiogenesis in brain microvascular endothelial cells against oxygen-glucose deprivation via targetting miR-145

Stroke is one of the leading causes of death and long-term disability around the world. Angiogenesis is supposed to protect brain microvascular endothelial cells (BMECs) from oxidative and ischemic stress. Previous studies indicated that interaction between metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and miR-145 was involved in myocardial ischemia reperfusion, suggesting MALAT1 and miR-145 were also mediated with the progress of angiogenesis and cell migration in oxygen-glucose deprivation (OGD)-induced BMECs. The present study aimed to investigate the functional roles of MALAT1 in regulating miR-145 and its downstream pro-angiogenesis factors, vascular endothelial growth factor (VEGF)-A and Angiopoietin-2 (ANGPT2) during the progress of angiogenesis in OGD-induced BMECs. An in vitro OGD model was employed in mouse BMECs to mimic brain hypoxic and ischemic conditions; MTT was used to determine cell viability. qRT-PCR was used to determine the expression of long non-coding RNA (lncRNA)-MALAT1 and miR-145 under OGD conditions; in vitro tube formation assay was used to investigate angiogenic effect of MALAT1 and miR-145 The relationship between lncRNA-MALAT1/miR-145 and miR-145/VEGF-A/ANGPT2 was evaluated by qRT-PCR and Western blot, and direct binding was assessed using dual luciferase assay. Results showed that the levels of lncRNA-MALAT1 and miR-145 were up-regulated in OGD-induced BMECs. miR-145 functioned as an anti-angiogenic and pro-apoptotic factor in OGD treated BMECs via down-regulating VEGF-A and ANGPT2 directly. While lncRNA-MALAT1 enhanced the expressions of VEGF-A and ANGPT2 by targetting miR-145 to promote angiogenesis and proliferation of BMECs under OGD conditions. Our present study revealed the inhibitory functions of miR-145 on angiogenesis through direct targetting on VEGF-A and ANGPT2 for the first time and proved the protective role of lncRNA-MALAT1 for BMECs under OGD conditions through the direct regulation of miR-145.

Hsa-miRNA-29a protects against high glucose-induced damage in human umbilical vein endothelial cells

Sustained exposure to high glucose (HG) results in dysfunction of vascular endothelial cells. Hence, diabetic patients often suffer from secondary vascular damages, such as vascular sclerosis and thrombogenesis, which may eventually cause cardiovascular problems. Thus, elucidating how HG results in vascular endothelial cell damage and finding an approach for prevention are important to prevent and treat vascular damages in diabetic patients. In the current study, we first showed that 72-hour exposure to HG-decreased hsa-miRNA-29a and increased the expression of Bcl-2 associated X protein (Bax), which subsequently inhibited Bcl-2 and promoted the expression of apoptotic protease activating factor-1 and activation of caspase-3, thus directly triggering the mitochondrial apoptotic pathway in human umbilical vein endothelial cells (HUVECs). Study of the underlying mechanism showed that hsa-miRNA-29a/Bax plays an essential role in the decreased proliferation and increased apoptosis of HUVECs induced by HG, and overexpression of hsa-miRNA-29a effectively inhibits HG-induced apoptosis and restores the proliferation and tube formation of HUVECs exposed to HG by inhibiting its target gene Bax. In short, our study demonstrates that hsa-miRNA-29a is a promising target for the prevention and treatment of vascular injury in diabetic patients.

TGF-β signaling alters H4K20me3 status via miR-29 and contributes to cellular senescence and cardiac aging

Cellular senescence is a well-orchestrated programmed process involved in age-related pathologies, tumor suppression and embryonic development. TGF-β/Smad is one of the predominant pathways that regulate damage-induced and developmentally programmed senescence. Here we show that canonical TGF-β signaling promotes senescence via miR-29-induced loss of H4K20me3. Mechanistically, oxidative stress triggers TGF-β signaling. Activated TGF-β signaling gives rise to acute accumulation of miR-29a and miR-29c, both of which directly suppress their novel target, Suv4-20h, thus reducing H4K20me3 abundance in a Smad-dependent manner, which compromises DNA damage repair and genome maintenance. Loss of H4K20me3 mediated by the senescent TGF-β/miR-29 pathway contributes to cardiac aging in vivo. Disruption of TGF-β signaling restores H4K20me3 and improves cardiac function in aged mice. Our study highlights the sequential mechanisms underlying the regulation of senescence, from senescence-inducing triggers to activation of responsive signaling followed by specific epigenetic alterations, shedding light on potential therapeutic interventions in cardiac aging.

Transforming growth factor-β signalling in renal fibrosis: from Smads to non-coding RNAs

Transforming growth factor-β (TGF-β) is the key player in tissue fibrosis. However, antifibrotic therapy targeting this multifunctional protein may interfere with other physiological processes to cause side effects. Thus, precise therapeutic targets need to be identified by further understanding the underlying mechanisms of TGF-β1 signalling during fibrogenesis. Equilibrium of Smad signalling is crucial for TGF-β-mediated renal fibrosis, where Smad3 is pathogenic but Smad2 and Smad7 are protective. The activation of TGF-β1/Smad signalling triggers extracellular matrix deposition, and local myofibroblast generation and activation. Mechanistic studies have shown that TGF-β/Smad3 transits the microRNA profile from antifibrotic to profibrotic and therefore promotes renal fibrosis via regulating non-coding RNAs at transcriptional levels. More importantly, disease-specific Smad3-dependent long non-coding RNAs have been recently uncovered from mouse kidney disease models and may represent novel precision therapeutic targets for chronic kidney disease. In this review, mechanisms of TGF-β-driven renal fibrosis via non-coding RNAs and their translational capacities will be discussed in detail.

MiR-29a: a potential therapeutic target and promising biomarker in tumors

MiRNAs, small non-coding RNA molecules, were recognized to be associated with the incidence and development of diverse neoplasms. MiRNAs were small non-coding RNAs that could regulate post-transcriptional level by binding to 3'-UTR of target mRNAs. Amongst which, miR-29a was demonstrated that it had significant impact on oncogenicity in various neoplasms through binding to critical genes which enhanced or inhibited the progression of cancers. MiR-29a participated in kinds of physiological and pathological processes, including virus replication, cell proliferation, differentiation, apoptosis, fibrosis, angiogenesis, tumorigenicity, metastasis, drug-resistance, and so on. According to its sufficient sensitivity and specificity, many studies showed that miR-29a might serve as a potential therapeutic target and promising biomarker in various tumors. In this review, we discussed the functions of miR-29a and its potential application in the diagnosis, treatment and stages of carcinoma, which could provide additional insight to develop a novel therapeutic strategy.

Preeclampsia Downregulates MicroRNAs in Fetal Endothelial Cells: Roles of miR-29a/c-3p in Endothelial Function

CONTEXT

Preeclampsia is a leading cause of fetal and maternal morbidity and mortality during pregnancy. Although the etiology of preeclampsia is unknown, preeclampsia offspring have increased risks of developing cardiovascular disorders in adulthood, implicating that preeclampsia programs fetal vasculature in utero.

OBJECTIVE

We hypothesize that preeclampsia alters expression profiles of endothelial microRNAs (miRNAs) in fetal endothelial cells and disturbs the vascular endothelial growth factor A (VEGFA)- and fibroblast growth factor 2 (FGF2)-induced endothelial function.

DESIGN AND SETTING

Unpassaged (P0) human umbilical vein endothelial cells (HUVECs) were isolated immediately after cesarean-section delivery from normotensive (NT) and preeclamptic (PE) pregnancies. Differentially expressed miRNAs between P0-HUVECs from NT and PE pregnancies were identified using a miRNA polymerase chain reaction (PCR) array and confirmed using reverse transcription quantitative PCR. To determine the function of these differentially expressed miRNAs, miRNAs of interest were knocked down in NT-HUVECs following by cell functional assays.

RESULTS

Sixteen miRNAs, including miR-29a/c-3p, were downregulated in P0-HUVECs from the PE group compared with the NT group. Bioinformatics analysis predicted the PI3K-v-akt murine thymoma viral oncogene homolog 1 (AKT) signaling pathway was dysregulated in P0-HUVECs from the PE group, which was associated with the miR-29a/c-3p downregulation. We further demonstrated that miR-29a/c-3p knockdown inhibited the VEGFA- and FGF2-induced endothelial migration as well as FGF2-induced AKT1 phosphorylation in HUVECs. However, miR-29a/c-3p knockdown did not alter the extracellular signal-regulated kinase 1/2 phosphorylation, cell proliferation, and endothelial monolayer integrity in response to VEGFA and FGF2 in HUVECs.

CONCLUSIONS

Preeclampsia-downregulated miR-29a/c-3p may impair fetal endothelial function by disturbing the FGF2-activated PI3K-AKT signaling pathway, hence inhibiting endothelial cell migration.

Dichotomous roles of TGF-β in human cancer

Transforming growth factor-β (TGF-β) mediates numerous biological processes, including embryonic development and the maintenance of cellular homeostasis in a context-dependent manner. Consistent with its central role in maintaining cellular homeostasis, inhibition of TGF-β signaling results in disruption of normal homeostatic processes and subsequent carcinogenesis, defining the TGF-β signaling pathway as a tumor suppressor. However, once carcinogenesis is initiated, the TGF-β signaling pathway promotes cancer progression. This dichotomous function of the TGF-β signaling pathway is mediated through altering effects on both the cancer cells, by inducing apoptosis and inhibiting proliferation, and the tumor microenvironment, by promoting angiogenesis and inhibiting immunosurveillance. Current studies support inhibition of TGF-β signaling either alone, or in conjunction with anti-angiogenic therapy or immunotherapy as a promising strategy for the treatment of human cancers.

Tumor angiogenesis revisited: Regulators and clinical implications

Since Judah Folkman hypothesized in 1971 that angiogenesis is required for solid tumor growth, numerous studies have been conducted to unravel the angiogenesis process, analyze its role in primary tumor growth, metastasis and angiogenic diseases, and to develop inhibitors of proangiogenic factors. These studies have led in 2004 to the approval of the first antiangiogenic agent (bevacizumab, a humanized antibody targeting vascular endothelial growth factor) for the treatment of patients with metastatic colorectal cancer. This approval launched great expectations for the use of antiangiogenic therapy for malignant diseases. However, these expectations have not been met and, as knowledge of blood vessel formation accumulates, many of the original paradigms no longer hold. Therefore, the regulators and clinical implications of angiogenesis need to be revisited. In this review, we discuss recently identified angiogenesis mediators and pathways, new concepts that have emerged over the past 10 years, tumor resistance and toxicity associated with the use of currently available antiangiogenic treatment and potentially new targets and/or approaches for malignant and nonmalignant neovascular diseases.

Elevated Plasma miR-29a Levels Are Associated with Increased Carotid Intima-Media Thickness in Atherosclerosis Patients

Atherosclerotic cardiovascular diseases, such as coronary heart disease, have become a major public health problem all over the world. MicroRNA-29a (miR-29a) modulates expression levels of collagen, inflammatory reaction and other extracellular matrix mRNAs, while adiponectin (APN), a circulating protein secreted by adipocytes, has anti-inflammatory properties. Both play multifaceted roles in angiogenesis or vascular remodelling. However, little is known about plasma miR-29a and APN levels in patients with atherosclerosis. We therefore investigated the relationship between the plasma levels of miR-29a or APN and carotid intima-media thickness (cIMT) in atherosclerosis patients (n = 85, cIMT ≥ 1.2 mm) and the controls (n = 85, cIMT < 1.2 mm). We found that the atherosclerosis group showed higher miR-29a levels (31.15 ± 3.99 vs. 26.39 ± 1.05 Ct, P < 0.001) and lower APN levels (15.93 ± 4.61 vs. 21.80 ± 7.74 ng/ml, P < 0.001), compared with control group. Thus, increased cIMT was associated with higher plasma miR-29a levels (r = 0.688, P < 0.001) and with lower plasma APN levels (r = -0.494, P < 0.001). Furthermore, multiple logistic regression analysis indicated that higher miR-29a levels (OR: 1.136, 95% CI: 1.042-1.240, P = 0.004) increased the risk for atherosclerosis, whereas higher APN levels appeared to be protective (OR: 0.122, 95% CI: 0.055-0.271, P < 0.001). The present study indicates that elevated miR-29a levels and reduced APN levels are associated with atherosclerosis.

Luteolin-7-diglucuronide attenuates isoproterenol-induced myocardial injury and fibrosis in mice

Myocardial injury and ensuing fibrotic alterations impair normal heart architecture and cause cardiac dysfunction. Oxidative stress has been recognized as a key player in the pathogenesis of cardiac injury and progression of cardiac dysfunction, and promoting fibrosis. In the current study we investigated whether luteolin-7-diglucuronide (L7DG), a naturally occurring antioxidant found in edible plants, could attenuate isoproterenol (ISO)-induced myocardial injury and fibrosis in mice and the underlying mechanisms. Myocardial injury and fibrosis were induced in mice via injection of ISO (5 mg·kg^-1·d^-1, ip) for 5 or 10 d. Two treatment regimens (pretreatment and posttreatment) were employed to administer L7DG (5-40 mg·kg^-1·d^-1, ip) into the mice. After the mice were euthanized, morphological examinations of heart sections revealed that both L7DG pretreatment and posttreatment regimens significantly attenuated ISO-induced myocardial injury and fibrosis. But the pretreatment regimen caused better protection against ISO-induced myocardial fibrosis than the posttreatment regimen. Furthermore, L7DG pretreatment blocked ISO-stimulated expression of the genes (Cyba, Cybb, Ncf1, Ncf4 and Rac2) encoding the enzymatic subunits of NADPH oxidase, which was the primary source of oxidant production in mammalian cells. Moreover, L7DG pretreatment significantly suppressed ISO-stimulated expression of collagen genes Col1a1, Col1a2, Col3a1, and Col12a1 and non-collagen extracellular matrix genes fibrillin-1, elastin, collagen triple helix repeat containing 1 and connective tissue growth factor. In addition, L7DG pretreatment almost reversed ISO-altered expression of microRNAs that were crosstalking with TGFβ-mediated fibrosis, including miR-29c-3p, miR-29c-5p, miR-30c-3p, miR-30c-5p and miR-21. The current study demonstrated for the first time that L7DG is pharmacologically effective in protecting the heart against developing ISO-induced injury and fibrosis, justifying further evaluation of L7DG as a cardioprotective agent to treat related cardiovascular diseases.

Upregulation of microRNA-574-3p in a human gastric cancer cell line AGS by TGF-β1

The mechanisms that regulate miR-574-3p expression in cells remain elusive. In the present study, we used real-time PCR assay to demonstrate TGF-β1-induced miR-574-3p upregulation in AGS cells, which was inhibited by TGF-β receptor I inhibitor SB431542. We used a computer search to identify Smad binding sites upstream of the miR-574-3p precursor sequence. We demonstrated that silencing Smad4, but not Smad2 or Smad3, significantly inhibited the TGF-β1-induced miR-574-3p upregulation in AGS cells. Furthermore, TGF-β1 significantly increased the activity of a dual-luciferase reporter that contains the Smad binding sites upstream of the miR-574 precursor sequence. Silencing Smad4 significantly inhibited the TGF-β1-induced increase in the activity of the reporter in AGS cells. ChIP assay showed that Smad4 directly bound to the promoter of miR-574-3p. MiR-574-3p inhibition was effective in eliminating the inhibition of AGS cell proliferation induced by TGF-β1, suggesting that TGF-β1 inducing upregulation of miR-574-3p is functionally significant.

Knockout of Angiotensin AT2 receptors accelerates healing but impairs quality

Wounds are among the most common, painful, debilitating and costly conditions in older adults. Disruption of the angiotensin type 1 receptors (AT₁R), has been associated with impaired wound healing, suggesting a critical role for AT₁R in this repair process. Biological functions of angiotensin type 2 receptors (AT₂R) are less studied. We investigated effects of genetically disrupting AT₂R on rate and quality of wound healing. Our results suggest that AT₂R effects on rate of wound closure depends on the phase of wound healing. We observed delayed healing during early phase of wound healing (inflammation). An accelerated healing rate was seen during later stages (proliferation and remodeling). By day 12, fifty percent of AT₂R^−/− mice had complete wound closure as compared to none in either C57/BL6 or AT₁R^−/− mice. There was a significant increase in AT₁R, TGFβ₁ and TGFβ₂ expression during the proliferative and remodeling phases in AT₂R^−/− mice. Despite the accelerated closure rate, AT₂R^−/− mice had more fragile healed skin. Our results suggest that in the absence of AT₂R, wound healing rate is accelerated, but yielded worse skin quality. Elucidating the contribution of both of the angiotensin receptors may help fine tune future intervention aimed at wound repair in older individuals.

Dual targeting of ANGPT1 and TGFBR2 genes by miR-204 controls angiogenesis in breast cancer

Deregulated expression of microRNAs has been associated with angiogenesis. Studying the miRNome of locally advanced breast tumors we unsuspectedly found a dramatically repression of miR-204, a small non-coding RNA with no previous involvement in tumor angiogenesis. Downregulation of miR-204 was confirmed in an independent cohort of patients and breast cancer cell lines. Gain-of-function analysis indicates that ectopic expression of miR-204 impairs cell proliferation, anchorage-independent growth, migration, invasion, and the formation of 3D capillary networks in vitro. Likewise, in vivo vascularization and angiogenesis were suppressed by miR-204 in a nu/nu mice model. Genome-wide profiling of MDA-MB-231 cells expressing miR-204 revealed changes in the expression of hundred cancer-related genes. Of these, we focused on the study of pro-angiogenic ANGPT1 and TGFβR2. Functional analysis using luciferase reporter and rescue assays confirmed that ANGPT1 and TGFβR2 are novel effectors downstream of miR-204. Accordingly, an inverse correlation between miR-204 and ANGPT1/TGFβR2 expression was found in breast tumors. Knockdown of TGFβR2, but not ANGPT1, impairs cell proliferation and migration whereas inhibition of both genes inhibits angiogenesis. Taken altogether, our findings reveal a novel role for miR-204/ANGPT1/TGFβR2 axis in tumor angiogenesis. We propose that therapeutic manipulation of miR-204 levels may represent a promising approach in breast cancer.

High Concentrations of Uric Acid Inhibit Endothelial Cell Migration via miR-663 Which Regulates Phosphatase and Tensin Homolog by Targeting Transforming Growth Factor-β1

BACKGROUND

Whether microRNAs participate in endothelial dysfunction HUA remains unknown. A previous study indicated that miR-663 was the most significantly differentially expressed endothelial microRNA under HUA conditions. Some studies have demonstrated that the miR-663 target gene and TGF-β1, promoted endothelial cell migration by inhibiting PTEN deleted on chromosome 10. Therefore, we hypothesized that HUA inhibits endothelial migration via miR-663, which regulates PTEN by targeting TGF-β1.

METHODS

PCR analysis was performed to determine miR-663 expression levels. A luciferase assay was performed to validate whether miR-663 targets TGF-β1 directly. Western blot analysis was performed to determine TGF-β1 and PTEN expression levels. An miR-663 inhibitor and TGF-β1- and PTEN-specific siRNAs were transfected into EA.hy926 cells to inhibit miR-663, TGF-β1, and PTEN expression, respectively. A wound healing assay was performed to determine the migratory ability of EA.hy926 cells.

RESULTS

miR-663 had higher expression levels in HUA-stimulated endothelial cells and in the sera of hyperuricemic patients and animals. TGF-β1 was targeted directly by miR-663. Endothelial miR-663 was up-regulated under HUA conditions, and HUA inhibited endothelial cell migration via miR-663, which targeted TGF-β1. Thus, TGF-β1 regulated cell migration in a PTEN-dependent manner.

CONCLUSION

HUA inhibits endothelial cell migration via miR-663, which regulates PTEN by targeting TGF-β1.

TGF-β-Regulated MicroRNAs and Their Function in Cancer Biology

The transforming growth factor-β (TGF-β) is known to regulate a large number of biological processes and is involved in various aspects of tumor development. Recent studies have shown that the biogenesis of miRNAs can be regulated by TGF-β signaling directly via Smad-dependent mechanisms and/or other unknown mechanisms, which may induce autoregulatory feedback loops in response to the activation of TGF-β signaling, influencing the fate of tumor cells. In this chapter, we summarize the currently described mechanisms underlying TGF-β's regulation of miRNA biogenesis, and the functional role of TGF-β-regulated miRNAs in tumor initiation, epithelial-mesenchymal transition, and tumor microenvironment modulation. Finally, we introduce methods to study TGF-β-regulated miRNAs and their functions in tumor progression and metastasis using an example of publication from our lab demonstrating the presence of a TGF-β-miR-34a-CCL22 signaling axis, which serves as a potent etiological pathway for the development of hepatocellular carcinoma venous metastases.

Noncoding RNAs in Tumor Angiogenesis

Solid tumors require angiogenesis to grow beyond 2 mm in size. In most cases, tumor cells undergo angiogenic switch and secrete substances that are required for generation of new capillary sprouting from existing blood vessels. Tumor angiogenesis is driven by a complex interplay between pro-angiogenic (VEGF/VEGFR, PDGF/PDGFR) and anti-angiogenic factors (TSP-1/TSP-2) within the tumor microenvironment. In addition, control of tissue remodeling and degradation by matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) contribute to tumor angiogenesis. Furthermore, tumor suppressors or oncogenes that control cellular motility and maintain or promote hypoxia (HIFs and MYC) are also actively playing roles in tumor angiogenesis. Noncoding RNAs (ncRNAs), including microRNAs, are a novel class of regulatory molecules that control the gene expression in a posttranscriptional manner. MicroRNAs regulate important physiological processes, such as proliferation, apoptosis, and differentiation, as well as pathological conditions including oncogenesis. Accumulating evidence suggests that microRNAs directly modulate the process of angiogenesis by targeting important angiogenic factors and signaling molecules. Understanding the molecular mechanism behind the regulation of angiogenesis by microRNAs is important due to their therapeutic potential which may lead to improving outcome for cancer patients. Besides, ncRNAs with a regulatory role in angiogenesis, such as long noncoding RNAs (lncRNAs), have been identified in the genome. However, the mechanisms of the vast majority of lncRNAs are currently unknown. For the few lncRNAs characterized at the functional level, accumulating evidence shows that they play important roles in malignant diseases. The function and mechanism in angiogenesis will be described in this chapter.

GDF10 is a signal for axonal sprouting and functional recovery after stroke

Stroke produces a limited process of neural repair. Axonal sprouting in cortex adjacent to the infarct is part of this recovery process, but the signal that initiates axonal sprouting is not known. Growth and differentiation factor 10 (GDF10) is induced in peri-infarct neurons in mice, non-human primates and humans. GDF10 promotes axonal outgrowth in vitro in mouse, rat and human neurons through TGFβRI and TGFβRII signaling. Using pharmacogenetic gain- and loss-of-function studies, we found that GDF10 produced axonal sprouting and enhanced functional recovery after stroke; knocking down GDF10 blocked axonal sprouting and reduced recovery. RNA sequencing from peri-infarct cortical neurons revealed that GDF10 downregulated PTEN, upregulated PI3 kinase signaling and induced specific axonal guidance molecules. Using unsupervised genome-wide association analysis of the GDF10 transcriptome, we found that it was not related to neurodevelopment, but may partially overlap with other CNS injury patterns. Thus, GDF10 is a stroke-induced signal for axonal sprouting and functional recovery.

Brain protection against ischemic stroke using choline as a new molecular bypass treatment

AIM

To determine whether administration of choline could attenuate brain injury in a rat model of ischemic stroke and the underlying mechanisms.

METHODS

A rat model of ischemic stroke was established through permanent middle cerebral artery occlusion (pMCAO). After the surgery, the rats were treated with choline or choline plus the specific α7 nAChR antagonist methyllycaconitine (MLA), or with the control drug nimodipine for 10 days. The neurological deficits, brain-infarct volume, pial vessel density and the number of microvessels in the cortex were assessed. Rat brain microvascular endothelial cells (rBMECs) cultured under hypoxic conditions were used in in vitro experiments.

RESULTS

Oral administration of choline (100 or 200 mg·kg(-1)·d(-1)) or nimodipine (20 mg·kg(-1)·d(-1)) significantly improved neurological deficits, and reduced infarct volume and nerve cell loss in the ischemic cerebral cortices in pMCAO rats. Furthermore, oral administration of choline, but not nimodipine, promoted the pial arteriogenesis and cerebral-cortical capillary angiogenesis in the ischemic regions. Moreover, oral administration of choline significantly augmented pMCAO-induced increases in the expression levels of α7 nAChR, HIF-1α and VEGF in the ischemic cerebral cortices as well as in the serum levels of VEGF. Choline-induced protective effects were prevented by co-treatment with MLA (1 mg·kg(-1)·d(-1), ip). Treatment of rBMECs cultured under hypoxic conditions in vitro with choline (1, 10 and 100 μmol/L) dose-dependently promoted the endothelial-cell proliferation, migration and tube formation, as well as VEGF secretion, which were prevented by co-treatment with MLA (1 μmol/L) or by transfection with HIF-1α siRNA.

CONCLUSION

Choline effectively attenuates brain ischemic injury in pMCAO rats, possibly by facilitating pial arteriogenesis and cerebral-cortical capillary angiogenesis via upregulating α7 nAChR levels and inducing the expression of HIF-1α and VEGF.

Regulatory RNAs controlling vascular (dys)function by affecting TGF-ß family signalling

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Over the last few years, microRNAs (miRNAs) have emerged as master regulators of gene expression in cardiovascular biology and disease. miRNAs are small endogenous non-coding RNAs that usually bind to 3′ untranslated region (UTR) of their target mRNAs and inhibit mRNA stability or translation of their target genes. miRNAs play a dynamic role in the pathophysiology of many CVDs through their effects on target mRNAs in vascular cells. Recently, numerous miRNAs have been implicated in the regulation of the transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signalling pathway which plays crucial roles in diverse biological processes, and is involved in pathogenesis of many diseases including CVD. This review gives an overview of current literature on the role of miRNAs targeting TGF-β/BMP signalling in vascular cells, including endothelial cells and smooth muscle cells. We also provide insight into how this miRNA-mediated regulation of TGF-β/BMP signalling might be used to harness CVD.

miR-29a promotes scavenger receptor A expression by targeting QKI (quaking) during monocyte-macrophage differentiation

Monocyte differentiation into macrophages results in upregulation of miR-29a and scavenger receptor A (SRA) expression, while the expression of RNA binding protein, QKI is suppressed. Since SRA is a functionally important protein in atherosclerosis, it is imperative to understand the various mechanisms involved in its regulation specially the mechanism involving miR-29a. There are individual studies linking miR-29a to SRA or QKI to monocyte differentiation but there is no evidence of any linkage among them. Therefore, we intend to investigate the association among these three, if any, in terms of regulation of SRA expression. Hence, in this study, the differentiated macrophages were initially transfected with miR-29a or its inhibitor and it was shown that QKI is a direct target of mir-29a. In addition, it was also observed by bioinformatics analysis that 3'UTR in SRA mRNA has QKI binding site. So, we attempted to further understand the role of QKI in SRA regulation. The macrophages were manipulated either with overexpression of QKI or by its ablation and it was observed that QKI suppressed SRA at the transcriptional level. Moreover, with the help of luciferase reporter vector, it was shown that QKI inhibited SRA transcription by binding to QRE region in its 3'UTR mRNA. Furthermore, to link the QKI mediated regulation of SRA expression with its functional activity; we analyzed lipid uptake capacity of macrophages transfected with either ectopic OKI plasmid or ablated for QKI. It was observed that, indeed, QKI upregulation inhibits lipid uptake by repressing SRA expression. Overall, our study demonstrates that miR-29a inhibits QKI, which in turn results in upregulation of SRA and lipid uptake.

The short and long of noncoding sequences in the control of vascular cell phenotypes

The two principal cell types of importance for normal vessel wall physiology are smooth muscle cells and endothelial cells. Much progress has been made over the past 20 years in the discovery and function of transcription factors that coordinate proper differentiation of these cells and the maintenance of vascular homeostasis. More recently, the converging fields of bioinformatics, genomics, and next generation sequencing have accelerated discoveries in a number of classes of noncoding sequences, including transcription factor binding sites (TFBS), microRNA genes, and long noncoding RNA genes, each of which mediates vascular cell differentiation through a variety of mechanisms. Alterations in the nucleotide sequence of key TFBS or deviations in transcription of noncoding RNA genes likely have adverse effects on normal vascular cell phenotype and function. Here, the subject of noncoding sequences that influence smooth muscle cell or endothelial cell phenotype will be summarized as will future directions to further advance our understanding of the increasingly complex molecular circuitry governing normal vascular cell differentiation and how such information might be harnessed to combat vascular diseases.

Contribution of microRNA to pathological fibrosis in cardio-renal syndrome: impact of uremic toxins

Progressive reduction in kidney function in patients following myocardial infarction (MI) is associated with an increase in circulating uremic toxins levels leading to increased extracellular matrix deposition. We have recently reported that treatment with uremic toxin adsorbent AST-120 in rats with MI inhibits serum levels of uremic toxin indoxyl sulfate (IS) and downregulates expression of cardiac profibrotic cytokine transforming growth factor beta (TGF-β1). In this study, we examined the effect of uremic toxins post-MI on cardiac microRNA-21 and microRNA-29b expression, and also the regulation of target genes and matrix remodeling proteins involved in TGFβ1 and angiotensin II signaling pathways. Sixteen weeks after MI, cardiac tissues were assessed for pathological and molecular changes. The percentage area of cardiac fibrosis was 4.67 ± 0.17 in vehicle-treated MI, 2.9 ± 0.26 in sham, and 3.32 ± 0.38 in AST-120-treated MI, group of rats. Compared to sham group, we found a twofold increase in the cardiac expression of microRNA-21 and 0.5-fold decrease in microRNA-29b in heart tissue from vehicle-treated MI. Treatment with AST-120 lowered serum IS levels and attenuated both, cardiac fibrosis and changes in expression of these microRNAs observed after MI. We also found increased mRNA expression of angiotensin-converting enzyme (ACE) and angiotensin receptor 1a (Agtr1a) in cardiac tissue collected from MI rats. Treatment with AST-120 attenuated both, expression of ACE and Agtr1a mRNA. Exposure of rat cardiac fibroblasts to IS upregulated angiotensin II signaling and altered the expression of both microRNA-21 and microRNA-29b. These results collectively suggest a clear role of IS in altering microRNA-21 and microRNA-29b in MI heart, via a mechanism involving angiotensin signaling pathway, which leads to cardiac fibrosis.

miR-185 plays an anti-hypertrophic role in the heart via multiple targets in the calcium-signaling pathways

MicroRNA (miRNA) is an endogenous non-coding RNA species that either inhibits RNA translation or promotes degradation of target mRNAs. miRNAs often regulate cellular signaling by targeting multiple genes within the pathways. In the present study, using Gene Set Analysis, a useful bioinformatics tool to identify miRNAs with multiple target genes in the same pathways, we identified miR-185 as a key candidate regulator of cardiac hypertrophy. Using a mouse model, we found that miR-185 was significantly down-regulated in myocardial cells during cardiac hypertrophy induced by transverse aortic constriction. To confirm that miR-185 is an anti-hypertrophic miRNA, genetic manipulation studies such as overexpression and knock-down of miR-185 in neonatal rat ventricular myocytes were conducted. The results showed that up-regulation of miR-185 led to anti-hypertrophic effects, while down-regulation led to pro-hypertrophic effects, suggesting that miR-185 has an anti-hypertrophic role in the heart. Our study further identified Camk2d, Ncx1, and Nfatc3 as direct targets of miR-185. The activity of Nuclear Factor of Activated T-cell (NFAT) and calcium/calmodulin-dependent protein kinase II delta (CaMKIIδ) was negatively regulated by miR-185 as assessed by NFAT-luciferase activity and western blotting. The expression of phospho-phospholamban (Thr-17), a marker of CaMKIIδ activity, was also significantly reduced by miR-185. In conclusion, miR-185 effectively blocked cardiac hypertrophy signaling through multiple targets, rendering it a potential drug target for diseases such as heart failure.