WNT Signaling in Cardiac and Vascular Disease

Roles of the Wnt Signaling Pathway in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most common type of head and neck tumor. It is a high incidence malignant tumor associated with a low survival rate and limited treatment options. Accumulating conclusions indicate that the Wnt signaling pathway plays a vital role in the pathobiological process of HNSCC. The canonical Wnt/β-catenin signaling pathway affects a variety of cellular progression, enabling tumor cells to maintain and further promote the immature stem-like phenotype, proliferate, prolong survival, and gain invasiveness. Genomic studies of head and neck tumors have shown that although β-catenin is not frequently mutated in HNSCC, its activity is not inhibited by mutations in upstream gene encoding β-catenin, NOTCH1, FAT1, and AJUBA. Genetic defects affect the components of the Wnt pathway in oral squamous cell carcinoma (OSCC) and the epigenetic mechanisms that regulate inhibitors of the Wnt pathway. This paper aims to summarize the groundbreaking discoveries and recent advances involving the Wnt signaling pathway and highlight the relevance of this pathway in head and neck squamous cell cancer, which will help provide new insights into improving the treatment of human HNSCC by interfering with the transcriptional signaling of Wnt.

Low-Dose Aspirin Prevents Kidney Damage in LPS-Induced Preeclampsia by Inhibiting the WNT5A and NF-κB Signaling Pathways

Preeclampsia (PE) is a serious pregnancy-related disease, and patients usually present with a high inflammatory response. Previous studies have suggested that aspirin (ASP) may have a role in alleviating the pathogenesis of preeclampsia. However, whether ASP can improve kidney damage and the mechanism for improving it is currently unclear. Here we optimized a lipopolysaccharide (LPS)-induced PE mouse model to identify the role of ASP in renal protection. We found that ASP treatment ameliorated LPS-induced renal failure and pathological changes, the tubular injury was significantly attenuated by ASP. Administration of ASP decreased the renal expression of pro-inflammatory factors, resulting in reduced kidney inflammation. The number of GALECTIN-3-positive cells was reduced, and the up-regulation of IL-6 and TNF-α was decreased. In addition, ASP also suppressed renal cell apoptosis and oxidative stress. An in vitro study indicated that ASP relieved LPS-induced HK-2 cell damage by inhibiting WNT5A/NF-κB signaling. Collectively, our data suggest that ASP is a useful therapeutic option for PE-related kidney injury.

aFGF alleviates diabetic endothelial dysfunction by decreasing oxidative stress via Wnt/β-catenin-mediated upregulation of HXK2

Vascular complications of diabetes are a serious challenge in clinical practice, and effective treatments are an unmet clinical need. Acidic fibroblast growth factor (aFGF) has potent anti-oxidative properties and therefore has become a research focus for the treatment of diabetic vascular complications. However, the specific mechanisms by which aFGF regulates these processes remain unclear. The purpose of this study was to investigate whether aFGF alleviates diabetic endothelial dysfunction by suppressing mitochondrial oxidative stress. We found that aFGF markedly decreased mitochondrial superoxide generation in both db/db mice and endothelial cells incubated with high glucose (30 mM) plus palmitic acid (PA, 0.1 mM), and restored diabetes-impaired Wnt/β-catenin signaling. Pretreatment with the Wnt/β-catenin signaling inhibitors IWR-1-endo (IWR) and ICG-001 abolished aFGF-mediated attenuation of mitochondrial superoxide generation and endothelial protection. Furthermore, the effects of aFGF on endothelial protection under diabetic conditions were suppressed by c-Myc knockdown. Mechanistically, c-Myc knockdown triggered mitochondrial superoxide generation, which was related to decreased expression and subsequent impaired mitochondrial localization of hexokinase 2 (HXK2). The role of HXK2 in aFGF-mediated attenuation of mitochondrial superoxide levels and EC protection was further confirmed by si-Hxk2 and a cell-permeable form of hexokinase II VDAC binding domain (HXK2VBD) peptide, which inhibits mitochondrial localization of HXK2. Taken together, these findings suggest that the endothelial protective effect of aFGF under diabetic conditions could be partly attributed to its role in suppressing mitochondrial superoxide generation via HXK2, which is mediated by the Wnt/β-catenin/c-Myc axis.

Dickkopf‑1/cysteine‑rich angiogenic inducer 61 axis mediates palmitic acid‑induced inflammation and apoptosis of vascular endothelial cells

Cardiovascular diseases (CVDs) are a major cause of mortality around the world, and the presence of atherosclerosis is the most common characteristic in patients with CVDs. Cysteine-rich angiogenic inducer 61 (CCN1) has been reported to serve an important role in the pathogenesis of atherosclerotic lesions. The aim of the present study was to investigate whether CCN1 could regulate the inflammation and apoptosis of endothelial cells induced by palmitic acid (PA). Dickkopf-1 (DKK1) is an important antagonist of the Wnt signaling pathway, which can specifically inhibit the classic Wnt signaling pathway. Firstly, the mRNA and protein expression levels of CCN1 were detected. Additionally, endothelial nitric oxide (NO) synthase (eNOS), DKK1, β-catenin, and inflammation- and apoptosis-associated proteins were measured. Detection of NO was performed using a commercial kit. The expression levels of inflammatory cytokines were assessed to explore the effect of CCN1 on PA-induced inflammation. TUNEL assay was used to detect the apoptosis of endothelial cells. The results revealed that PA upregulated the expression levels of CCN1, inflammatory cytokines and pro-apoptotic proteins in endothelial cells. PA decreased the production of NO, and the levels of phosphorylated-eNOS, whereas knockdown of CCN1 partially abrogated these effects triggered by PA. Furthermore, the Wnt/β-catenin signaling pathway was activated in PA-induced endothelial cells; however, the levels of DKK1 were downregulated. Overexpression of DKK1 could reduce CCN1 expression via inactivation of the Wnt/β-catenin signaling pathway. In conclusion, knockdown of CCN1 attenuated PA-induced inflammation and apoptosis of endothelial cells via inactivating the Wnt/β-catenin signaling pathway.

The Interplay of WNT and PPARγ Signaling in Vascular Calcification

Vascular calcification (VC), the ectopic deposition of calcium phosphate crystals in the vessel wall, is one of the primary contributors to cardiovascular death. The pathology of VC is determined by vascular topography, pre-existing diseases, and our genetic heritage. VC evolves from inflammation, mediated by macrophages, and from the osteochondrogenic transition of vascular smooth muscle cells (VSMC) in the atherosclerotic plaque. This pathologic transition partly resembles endochondral ossification, involving the chronologically ordered activation of the β-catenin-independent and -dependent Wingless and Int-1 (WNT) pathways and the termination of peroxisome proliferator-activated receptor γ (PPARγ) signal transduction. Several atherosclerotic plaque studies confirmed the differential activity of PPARγ and the WNT signaling pathways in VC. Notably, the actively regulated β-catenin-dependent and -independent WNT signals increase the osteochondrogenic transformation of VSMC through the up-regulation of the osteochondrogenic transcription factors SRY-box transcription factor 9 (SOX9) and runt-related transcription factor 2 (RUNX2). In addition, we have reported studies showing that WNT signaling pathways may be antagonized by PPARγ activation via the expression of different families of WNT inhibitors and through its direct interaction with β-catenin. In this review, we summarize the existing knowledge on WNT and PPARγ signaling and their interplay during the osteochondrogenic differentiation of VSMC in VC. Finally, we discuss knowledge gaps on this interplay and its possible clinical impact.

hGC33-Modified and Sorafenib-Loaded Nanoparticles have a Synergistic Anti-Hepatoma Effect by Inhibiting Wnt Signaling Pathway

Delivery of tumor-specific inhibitors is a challenge in cancer treatment. Antibody-modified nanoparticles can deliver their loaded drugs to tumor cells that overexpress specific tumor-associated antigens. Here, we constructed sorafenib-loaded polyethylene glycol-b-PLGA polymer nanoparticles modified with antibody hGC33 to glypican-3 (GPC3 +), a membrane protein overexpressed in hepatocellular carcinoma. We found that hGC33-modified NPs (hGC33-SFB-NP) targeted GPC3⁺ hepatocellular carcinoma (HCC) cells by specifically binding to GPC3 on the surface of HCC cells, inhibited Wnt-induced signal transduction, and inhibited HCC cells in G0/1 by down-regulating cyclin D1 expression, thus attenuating HCC cell migration by inhibiting epithelial-mesenchymal transition. hGC33-SFB-NP inhibited the migration, cycle progression, and proliferation of HCC cells by inhibiting the Ras/Raf/MAPK pathway and the Wnt pathway in tandem with GPC3 molecules, respectively. hGC33-SFB-NP inhibited the growth of liver cancer in vivo and improved the survival rate of tumor-bearing mice. We conclude that hGC33 increases the targeting of SFB-NP to HCC cells. hGC33-SFB-NP synergistically inhibits the progression of HCC by blocking the Wnt pathway and the Ras/Raf/MAPK pathway.

Signalling pathways implicated in the pathogenesis of rheumatic heart disease (Review)

Rheumatic heart disease (RHD) is frequently encountered in underdeveloped areas and primarily affects patients under the age of 40 years old. The pathogenesis of RHD has yet to be fully elucidated and surgical treatment remains the only option, which is expensive and technically demanding for patients in less developed areas. Signalling pathways are crucial for the occurrence and development of several diseases, and researchers worldwide have made progress in elucidating the signalling pathways associated with the pathogenesis of RHD. The aim of the present review was to discuss 6 signalling pathways implicated in the pathogenesis of RHD, summarize the methods and progress of these studies and propose future research directions. Important information on the pathogenesis of RHD according to the current progress of signalling pathway studies was also summarized, in the hope that this review may serve as a reference for future research on the signalling pathways involved in the pathogenesis of RHD.

Oxidized Low-Density Lipoprotein Induces WNT5A Signaling Activation in THP-1 Derived Macrophages and a Human Aortic Vascular Smooth Muscle Cell Line

The pathogenesis of atherosclerosis is complex, evolves, and involves many cell types. Macrophages and vascular smooth muscle cells (VSMCs) are critically involved in atherosclerosis development and progression. Several studies have shown that WNT5A protein is abundantly expressed in human atherosclerotic lesions; however, the mechanism and role of WNT signaling pathway activation is not clearly known. Using THP-1 derived macrophages, and human aortic VSMC cells, we evaluated in vitro how oxidized low-density lipoprotein (oxLDL) and WNT5A signaling interact in these two cell lines. We used western blot, scratch assay, metabolic proliferation assay, as well as immunostaining to analyze the effect of Wnt signaling activation. The results demonstrated that oxLDL, as well as WNT5A (control), induced Disheveled-2 (DVL2) activation and Kif26b degradation, indicating activation of non-canonical Wnt signaling. We found that oxLDL and WNT5A induced FZD5-ROR2 co-localization at the cellular membrane in vitro in THP-1 derived macrophages. Box5 (FZD5 receptor antagonist) inhibited oxLDL-induced DVL2/JNK activation secondary to newly secreted WNT protein from THP-1 derived macrophages. We found that WNT3A (canonical Wnt) and WNT5A showed different roles in this VSMC cell line. These findings indicate that WNT5A is upregulated by oxLDL, promotes foam cell formation, and affects VSMC phenotype and migration in these two cell lines. Also, in these cell lines FZD5 signaling seems to be necessary for lipid accumulation and, through this mechanism, WNT5A could modulate foam cell formation. Thus, our results suggest that WNT5A may contribute to the pathogenesis of vascular disease through modulating macrophage and VSMC behavior.

Wnt Signaling Mediates Pro-Fibrogenic Activity in Human Aortic Valve Interstitial Cells

BACKGROUND

Proinflammatory activation of toll-like receptor-4 (TLR4) drives phenotypic changes in aortic valve interstitial cells (AVICs) and produces a fibrogenic phenotype that mediates valvular fibrosis and contributes to aortic stenosis. Prior work identified upregulated Wnt signaling in AVICs taken from valves affected by aortic stenosis. Our purpose was to determine the contribution of Wnt signaling to TLR4-dependent fibrogenic activity in isolated human AVICs.

METHODS

Human AVICs were isolated from hearts explanted for cardiac transplantation (N = 4). To test whether Wnt signaling contributed to TLR4-dependent fibrogenic activity, AVICs were treated with Wnt inhibitor (Dkk1) prior to TLR4 activation (LPS) and fibrogenic markers assessed. To determine the mediator of TLR4-to-Wnt signaling, expression of the key Wnt ligand, Wnt3a, was assessed after TLR4 activation and neutralizing antibodies confirmed the identity of the mediator. Fibrogenic activity was assessed after AVICs were treated with recombinant Wnt3a. Statistics were by analysis of variance (P < .05).

RESULTS

TLR4 activation upregulated in vitro collagen deposition, type IV collagen and MMP2 expression, and Dkk1 inhibited these responses (P < .05). Expression of Wnt3a was upregulated after TLR4 activation (P < .05). Anti-Wnt3a neutralizing antibodies abrogated TLR4-dependent type IV collagen and MMP2 expression (P < .05). Wnt3a upregulated type IV collagen and MMP2 expression independent of TLR4 activation (P < .05).

CONCLUSIONS

This study found that TLR4-dependent fibrogenic activity was mediated through Wnt signaling. The mediator of profibrogenic TLR4-to-Wnt signaling was a key Wnt ligand, Wnt3a. The abrogation of TLR4-induced fibrogenic activity in human AVICs by Wnt blockade illustrates a potential therapeutic role for Wnt inhibition in treatment and/or prevention of aortic stenosis.

Circ-ZNF124 downregulation inhibits non-small cell lung cancer progression partly by inactivating the Wnt/β-catenin signaling pathway via mediating the miR-498/YES1 axis

Non-small cell lung cancer (NSCLC) is a major type of lung cancer, leading to a high fatality rate. The role of circular RNAs (circRNAs) in cancer has been increasingly emphasized and studied. However, the function of circ-ZNF124 in NSCLC is largely unclear, and associated regulatory mechanism is not studied. Here, we examined the expression pattern of circ-ZNF124 using quantitative real-time PCR. For functional analysis, cell proliferation, cell apoptosis/cycle and cell invasion were investigated using MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay, flow cytometry assay and transwell assay, respectively. As results, we found that the expression of circ-ZNF124 was elevated in NSCLC tissues and cells. Functionally, circ-ZNF124 downregulation inhibited NSCLC cell proliferation and invasion but induced apoptosis and cycle arrest in vitro, and blocked tumor growth in vivo by animal experiments. Mechanistically, we identified that miR-498 was a target of circ-ZNF124, and miR-498 directly bound to YES proto-oncogene 1 (YES1). Besides, rescue experiments discovered that the cellular effects caused by circ-ZNF124 downregulation could be reversed by miR-498 inhibition or YES1 overexpression. Moreover, we discovered that circ-ZNF124 downregulation inactivated the expression of β-catenin and c-Myc by mediating the miR-498/YES axis. In conclusion, these findings supported that circ-ZNF124 regulated the expression of YES1 by acting as a sponge of miR-498, thus restraining NSCLC development by inactivating the Wnt/β-catenin signaling pathway, which provided a novel strategy to treat NSCLC.

HECT (Homologous to the E6-AP Carboxyl Terminus)-Type Ubiquitin E3 Ligase ITCH Attenuates Cardiac Hypertrophy by Suppressing the Wnt/β-Catenin Signaling Pathway

The HECT (homologous to the E6-AP carboxyl terminus)-type ubiquitin E3 ligase ITCH is an enzyme that plays an important role in ubiquitin-proteasomal protein degradation. Disheveled proteins (Dvl1 [disheveled protein 1], Dvl2, and Dvl3) are the main components of the Wnt/β-catenin signaling pathway, which is involved in cardiac hypertrophy. The aim of this study was to examine the role of ITCH during development of cardiac hypertrophy. Thoracic transverse aortic constriction (TAC) was performed in transgenic mice with cardiac-specific overexpression of ITCH (ITCH-Tg) and wild-type mice. Cardiac hypertrophy after TAC was attenuated in ITCH-Tg mice, and the survival rate was higher for ITCH-Tg mice than for wild-type mice. Protein interaction between ITCH and Dvls was confirmed with immunoprecipitation in vivo and in vitro. Expression of key molecules of the Wnt/β-catenin signaling pathway (Dvl1, Dvl2, GSK3β [glycogen synthase kinase 3β], and β-catenin) was inhibited in ITCH-Tg mice compared with wild-type mice. Notably, the ubiquitination level of Dvl proteins increased in ITCH-Tg mice. Protein and mRNA expression levels of ITCH increased in response to Wnt3a stimulation in neonatal rat cardiomyocytes. Knockdown of ITCH using small-interfering RNA increased cardiomyocyte size and augmented protein expression levels of Dvl proteins, phospho-GSK3β, and β-catenin after Wnt3a stimulation in cardiomyocytes. Conversely, overexpression of ITCH attenuated cardiomyocyte hypertrophy and decreased protein expression levels of Dvl proteins, phospho-GSK3β and β-catenin. In conclusion, ITCH targets Dvl proteins for ubiquitin-proteasome degradation in cardiomyocytes and attenuates cardiac hypertrophy by suppressing the Wnt/β-catenin signaling pathway.

Significant Associations between AXIN1 rs1805105, rs12921862, rs370681 Haplotypes and Variant Genotypes of AXIN2 rs2240308 with Risk of Congenital Heart Defects

This study aimed to investigate possible associations of the susceptibility to congenital heart defects (CHDs) with AXIN1 rs1805105, rs12921862 and rs370681 gene variants and haplotypes, and AXIN2 rs2240308 gene variant. Significant associations were identified for AXIN1 rs370681 and AXIN2 rs2240308 variants. AXIN1 rs370681 variant was significantly associated with decreased odds of CHDs (adjusted OR varying from 0.13 to 0.28 in codominant, dominant and recessive gene models), while the AXIN2 rs2240308 variant was associated with increased odds of CHD in the dominant model. The haplotype-based generalized linear model regression of AXIN1 rs1805105, rs12921862 and rs370681 variants revealed that C-C-C and C-C-T haplotypes significantly increased the risk of CHDs (p < 0.05). No significant second order epistatic interactions were found between investigated variants (AXIN1 rs1805105, rs12921862, rs370681, and AXIN2 rs2240308). Our conclusion is that AXIN1 rs1805105, rs12921862, and rs370681 (C-C-C and C-C-T) haplotypes and AXIN2 rs2240308 contribute to CHDs susceptibility.

Angiogenesis after acute myocardial infarction

Acute myocardial infarction (MI) inflicts massive injury to the coronary microcirculation leading to vascular disintegration and capillary rarefication in the infarct region. Tissue repair after MI involves a robust angiogenic response that commences in the infarct border zone and extends into the necrotic infarct core. Technological advances in several areas have provided novel mechanistic understanding of postinfarction angiogenesis and how it may be targeted to improve heart function after MI. Cell lineage tracing studies indicate that new capillary structures arise by sprouting angiogenesis from pre-existing endothelial cells (ECs) in the infarct border zone with no meaningful contribution from non-EC sources. Single-cell RNA sequencing shows that ECs in infarcted hearts may be grouped into clusters with distinct gene expression signatures, likely reflecting functionally distinct cell populations. EC-specific multicolour lineage tracing reveals that EC subsets clonally expand after MI. Expanding EC clones may arise from tissue-resident ECs with stem cell characteristics that have been identified in multiple organs including the heart. Tissue repair after MI involves interactions among multiple cell types which occur, to a large extent, through secreted proteins and their cognate receptors. While we are only beginning to understand the full complexity of this intercellular communication, macrophage and fibroblast populations have emerged as major drivers of the angiogenic response after MI. Animal data support the view that the endogenous angiogenic response after MI can be boosted to reduce scarring and adverse left ventricular remodelling. The improved mechanistic understanding of infarct angiogenesis therefore creates multiple therapeutic opportunities. During preclinical development, all proangiogenic strategies should be tested in animal models that replicate both cardiovascular risk factor(s) and the pharmacotherapy typically prescribed to patients with acute MI. Considering that the majority of patients nowadays do well after MI, clinical translation will require careful selection of patients in need of proangiogenic therapies.

Non-Canonical WNT5A Signaling Through RYK Contributes to Aggressive Phenotype of the Rheumatoid Fibroblast-Like Synoviocytes

We hypothesized that WNT5A could contribute to the enhanced migration and invasiveness of rheumatoid arthritis fibroblast-like synoviocytes (RA FLS), which is one of the incompletely understood aspects of the RA FLS aggressive phenotype. This hypothesis is based on the previous evidence of a WNT5A role in both, RA and cell migration. Migration and invasion of RA FLS were assessed after incubation with recombinant Wnt5a (rWnt5a) or silencing of the endogenous WNT5A expression. The expression of WNT5A, WNT receptors, cytokines, chemokines, and metalloproteinases was quantified with RT-PCR. The WNT pathway was explored with gene silencing, antibody and pharmacological inhibition followed by migration assays and phosphoprotein western blots. Here, we reported that rWnt5a promoted migration and invasion of RA FLS, whereas knockdown of the endogenous WNT5A reduced them. These effects were specific to the RA FLS since they were not observed in FLS from osteoarthritis (OA) patients. Also, rWnt5a induced the expression of IL6, IL8, CCL2, CXCL5, MMP1, MMP3, MMP9, and MMP13 from baseline or potentiating the TNF induction, WNT5A signaling required the RYK receptor and was mediated through the WNT/Ca²⁺ and the ROCK pathway. These pathways involved the RYK and ROCK dependent activation of the p38, ERK, AKT, and GSK3β kinases, but not the activation of JNK. Together these findings indicate that WNT5A contributes to the enhanced migration and invasiveness of RA FLS through RYK and the specific activation of ROCK and downstream kinases.

A neutralizing antibody against DKK1 does not reduce plaque formation in classical murine models of atherosclerosis: Is the therapeutic potential lost in translation?

BACKGROUND AND AIMS

Clinical interventions targeting nonlipid risk factors are needed given the high residual risk of atherothrombotic events despite effective control of dyslipidemia. Dickkopf-1 (DKK1) plays a lipid-independent role in vascular pathophysiology but its involvement in atherosclerosis development and its therapeutic attractiveness remain to be established.

METHODS

Patient data, in vitro studies and pharmacological intervention in murine models of atherosclerosis were utilized.

RESULTS

In patients' material (n = 127 late stage plaque specimens and n = 10 control vessels), DKK1 mRNA was found to be higher in atherosclerotic plaques versus control arteries. DKK1 protein was detected in the luminal intimal area and in the necrotic core of plaques. DKK1 was released from isolated primary human platelets (~12 - 21-fold) and endothelial cells (~1.4-2.5-fold) upon stimulation with different pathophysiological stimuli. In ApoE^-/- and Ldlr^-/- mice, plasma DKK1 concentrations were similar to those observed in humans, whereas DKK1 expression in different atheroprone arterial segments was very low/absent. Chronic treatment with a neutralizing DKK1 antibody effectively reduced plasma concentrations, however, plaque lesion area was not reduced in ApoE^-/- and Ldlr^-/- mice fed a western diet for 14 and 16 weeks. Anti-DKK1 treatment increased bone volume and bone mineral content.

CONCLUSIONS

Functional inhibition of DKK1 with an antibody does not alter atherosclerosis progression in classical murine models. This may reflect the absence of DKK1 expression in plaques and more advanced animal disease models could be needed to evaluate the role and therapeutic attractiveness of DKK1 in late stage complications such as plaque destabilization, calcification, rupture and thrombosis.

Leptin promotes endothelial dysfunction in chronic kidney disease by modulating the MTA1-mediated WNT/β-catenin pathway

Endothelial dysfunction (ED) has a high incidence in chronic kidney disease (CKD) and is identified as a precursor to cardiovascular events. Recent studies suggest that leptin may be the missing link between ED and CKD. The objective of this study was to investigate the mechanism by which leptin causes ED and the connection with leptin and indicators of ED in CKD patients. Analysis of leptin-treated human umbilical vein endothelial cells (HUVECs) showed increased expression of interleukin 6 (IL-6), endothelin 1 (ET-1) and human monocyte chemoattractant protein 1 (MCP-1), resulting in F-actin recombination and vinculin aggregation as well as endothelial cell migration. In vitro studies have shown that leptin leads to increased WNT1 expression and the accumulation of β-catenin. Metastasis-associated protein 1 (MTA1), a critical upstream modifier of WNT1 signaling, increased the expression level in leptin-mediated regulation. In contrast, opposite results were observed when cells are transfected with MTA1 or WNT1 shRNA lentivirus vectors. Among 160 patients with CKD and 160 healthy subjects, patients with CKD had significantly higher serum leptin levels than those of the control group, which were positively correlated with increased levels of IL-6, ET-1 and MCP-1. However, these levels were negatively correlated with flow-mediated dilatation (FMD). Hence, these investigations provided novel information on the increased serum leptin levels in CKD patients leading to ED via the MTA1-WNT/β-catenin pathway.

The role of Wnt signalling in development of coronary artery disease and its risk factors

The Wnt signalling pathways are composed of a highly conserved cascade of events that govern cell differentiation, apoptosis and cell orientation. Three major and distinct Wnt signalling pathways have been characterized: the canonical Wnt pathway (or Wnt/β-catenin pathway), the non-canonical planar cell polarity pathway and the non-canonical Wnt/Ca2+ pathway. Altered Wnt signalling pathway has been associated with diverse diseases such as disorders of bone density, different malignancies, cardiac malformations and heart failure. Coronary artery disease is the most common type of heart disease in the United States. Atherosclerosis is a multi-step pathological process, which starts with lipid deposition and endothelial cell dysfunction, triggering inflammatory reactions, followed by recruitment and aggregation of monocytes. Subsequently, monocytes differentiate into tissue-resident macrophages and transform into foam cells by the uptake of modified low-density lipoprotein. Meanwhile, further accumulations of lipids, infiltration and proliferation of vascular smooth muscle cells, and deposition of the extracellular matrix occur under the intima. An atheromatous plaque or hyperplasia of the intima and media is eventually formed, resulting in luminal narrowing and reduced blood flow to the myocardium, leading to chest pain, angina and even myocardial infarction. The Wnt pathway participates in all different stages of this process, from endothelial dysfunction to lipid deposit, and from initial inflammation to plaque formation. Here, we focus on the role of Wnt cascade in pathophysiological mechanisms that take part in coronary artery disease from both clinical and experimental perspectives.

Genetic Tools to Study Cardiovascular Biology

Progress in biomedical science is tightly associated with the improvement of methods and genetic tools to manipulate and analyze gene function in mice, the most widely used model organism in biomedical research. The joint effort of numerous individual laboratories and consortiums has contributed to the creation of a large genetic resource that enables scientists to image cells, probe signaling pathways activities, or modify a gene function in any desired cell type or time point, à la carte. However, as these tools significantly increase in number and become more sophisticated, it is more difficult to keep track of each tool's possibilities and understand their advantages and disadvantages. Knowing the best currently available genetic technology to answer a particular biological question is key to reach a higher standard in biomedical research. In this review, we list and discuss the main advantages and disadvantages of available mammalian genetic technology to analyze cardiovascular cell biology at higher cellular and molecular resolution. We start with the most simple and classical genetic approaches and end with the most advanced technology available to fluorescently label cells, conditionally target their genes, image their clonal expansion, and decode their lineages.

Wnt Pathway: An Emerging Player in Vascular and Traumatic Mediated Brain Injuries

The Wnt pathway, which comprises the canonical and non-canonical pathways, is an evolutionarily conserved mechanism that regulates crucial biological aspects throughout the development and adulthood. Emergence and patterning of the nervous and vascular systems are intimately coordinated, a process in which Wnt pathway plays particularly important roles. In the brain, Wnt ligands activate a cell-specific surface receptor complex to induce intracellular signaling cascades regulating neurogenesis, synaptogenesis, neuronal plasticity, synaptic plasticity, angiogenesis, vascular stabilization, and inflammation. The Wnt pathway is tightly regulated in the adult brain to maintain neurovascular functions. Historically, research in neuroscience has emphasized essentially on investigating the pathway in neurodegenerative disorders. Nonetheless, emerging findings have demonstrated that the pathway is deregulated in vascular- and traumatic-mediated brain injuries. These findings are suggesting that the pathway constitutes a promising target for the development of novel therapeutic protective and restorative interventions. Yet, targeting a complex multifunctional signal transduction pathway remains a major challenge. The review aims to summarize the current knowledge regarding the implication of Wnt pathway in the pathobiology of ischemic and hemorrhagic stroke, as well as traumatic brain injury (TBI). Furthermore, the review will present the strategies used so far to manipulate the pathway for therapeutic purposes as to highlight potential future directions.

The Role of Wnt/β-Catenin Pathway Mediators in Aortic Valve Stenosis

Aortic valve stenosis (AVS) is a prevailing and life-threatening cardiovascular disease in adults over 75 years of age. However, the molecular mechanisms governing the pathogenesis of AVS are yet to be fully unraveled. With accumulating evidence that Wnt signaling plays a key role in the development of AVS, the involvement of Wnt molecules has become an integral study target in AVS pathogenesis. Thus, we hypothesized that the Wnt/β-catenin pathway mediators, SFRP2, DVL2, GSK3β and β-catenin are dysregulated in patients with AVS. Using immunohistochemistry, Real-Time qPCR and Western blotting, we investigated the presence of SFRP2, GSK-3β, DVL2, and β-catenin in normal and stenotic human aortic valves. Markedly higher mRNA and protein expression of GSK-3β, DVL2, β-catenin and SFRP2 were found in stenotic aortic valves. This was further corroborated by observation of their abundant immunostaining, which displayed strong immunoreactivity in diseased aortic valves. Proteomic analyses of selective GSK3b inhibition in calcifying human aortic valve interstitial cells (HAVICs) revealed enrichment of proteins involved organophosphate metabolism, while reducing the activation of pathogenic biomolecular processes. Lastly, use of the potent calcification inhibitor, Fetuin A, in calcifying HAVICs significantly reduced the expression of Wnt signaling genes Wnt3a, Wnt5a, Wnt5b, and Wnt11. The current findings of altered expression of canonical Wnt signaling in AVS suggest a possible role for regulatory Wnts in AVS. Hence, future studies focused on targeting these molecules are warranted to underline their role in the pathogenesis of the disease.

LINC00941 promotes oral squamous cell carcinoma progression via activating CAPRIN2 and canonical WNT/β-catenin signaling pathway

Dysregulation of long non-coding RNAs (lncRNAs) has been implicated in many cancer developments. Previous studies showed that lncRNA LINC00941 was aberrantly expressed in oral squamous cell carcinoma (OSCC). However, its role in OSCC development remains elusive. In this study, we demonstrated that in OSCC cells, EP300 activates LINC00941 transcription through up-regulating its promoter H3K27ac modification. Up-regulated LINC00941 in turn activates CAPRIN2 expression by looping to CAPRIN2 promoter. Functional assays suggest that both LINC00941 and CAPRIN2 play pivotal roles in promoting OSCC cell proliferation and colony formation. In vivo assay further confirmed the role of LINC00941 in promoting OSCC cell tumour formation. Lastly, we showed that the role of LINC00941 and CAPRIN2 in OSCC progression was mediated through activating the canonical WNT/β-catenin signaling pathway. Thus, LINC00941/CAPRIN2/ WNT/β-catenin signaling pathway provides new therapeutic targets for OSCC treatment.

Identification of KIAA0196 as a novel susceptibility gene for myofibril structural disorganization in cardiac development

BACKGROUND

Congenital heart disease is one of the most common cardiac malformation-related diseases worldwide. Some causative genes have been identified but can explain only a small proportion of all cases; therefore, the discovery of novel susceptibility genes and/or modifier genes for abnormal cardiac development remains a major challenge.

METHODS

We used a single nucleotide polymorphism (SNP) array, and next-generation sequencing (NGS) was conducted to screen and quickly identify candidate genes. KIAA0196 knockout zebrafish and mice were generated by CRISPR/Cas9 to detect whether or how KIAA0196 deficiency would influence cardiac development.

RESULTS

Homozygous, but not heterozygous, zebrafish and mice showed early embryonic lethality. At the embryonic stage, microscopic examination and dissection revealed pericardial edema and ventricle enlargement in homozygous zebrafish and obviously delayed cardiac development in heterozygous mice, while echocardiography and tissue staining showed that significantly decreased cardiac function, ventricle enlargement, myofibril loss, and significantly reduced trabecular muscle density were observed in adult heterozygous zebrafish and mice. Most importantly, immunostaining and electron microscopy showed that there was a significant increase in sarcomere structural disorganization and myofibril structural integrity loss in KIAA0196 mutants. Furthermore, substantial downregulation in other sarcomeric genes and proteins was detected and verified in a mouse model via transcriptome and proteomics analyses; these changes especially affected the myosin heavy or light chain (MYH or MYL) family genes.

CONCLUSION

We identified KIAA0196 for the first time as a susceptibility gene for abnormal cardiac development. KIAA0196 deficiency may cause abnormal heart development by influencing the structural integrity of myofibrils.

Prognostic Value of Secreted Frizzled-Related Protein 5 in Heart Failure Patients With and Without Type 2 Diabetes Mellitus

BACKGROUND

Patients with heart failure (HF) with diabetes mellitus have distinct biomarker profiles compared with those without diabetes mellitus. SFRP5 (secreted frizzled-related protein 5) is an anti-inflammatory adipokine with an important suppressing role on the development of type 2 diabetes mellitus (T2DM). This study aimed to evaluate the prognostic value of SFRP5 in patients with HF with and without T2DM.

METHODS

The study included 833 consecutive patients with HF, 312 (37.5%) of whom had T2DM. Blood samples were collected at presentation, and SFRP5 levels were measured. The primary outcome was the composite end points of first occurrence of HF rehospitalization or all-cause mortality during follow-up.

RESULTS

During median follow-up of 2.1 years, 335 (40.2%) patients in the cohort experienced the composite primary outcome. After adjustment for multiple risk factors, each doubling of SFRP5 level was associated with a 21% decreased risk of primary outcomes in the overall study population (P<0.001). Subgroup analyses showed that the association between level of SFPR5 and primary outcomes may be stronger in patients with T2DM (hazard ratio, 0.69 [95% CI, 0.61-0.79]) than in patients without T2DM (hazard ratio, 0.89 [95% CI, 0.79-1.01]; interaction P=0.006). Similar associations were observed when taking SFRP5 as a categorical variable. Addition of SFRP5 significantly improved discrimination and reclassification of the incident primary outcomes beyond clinical risk factors and N-terminal pro-B-type natriuretic peptide in all patients with HF and those with T2DM (all P<0.01).

CONCLUSIONS

SFRP5 is an independent novel biomarker for risk stratification in HF, especially in HF with T2DM.

XQ-1H attenuates ischemic injury in PC12 cells via Wnt/β-catenin signaling though inhibition of apoptosis and promotion of proliferation

10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H) is a new derivative of ginkgolide B and has previously been proven to exert neuroprotective effects on ischemic injury. However, it is not clear whether XQ-1H affects the cell survival and proliferation in oxygen-glucose deprivation/reoxygenation (OGD/R) damaged PC12 cells. Our results showed that OGD/R improved cell viability after 24 hr of posttreatment with XQ-1H (10 or 5 μM), inhibiting cell injury and apoptosis by upregulating the expression of brain-derived neurotrophic factor, nerve growth factor, and antiapoptotic B-cell lymphoma-extra large, while reducing proapoptotic cleaved caspase-3 protein. By introducing the Wnt/β-catenin signaling inhibitor XAV-939 and 5-bromo-2'-deoxyuridine staining, it was proved that XQ-1H promoted the proliferation of PC12 cells in a Wnt-signal-dependent manner via inhibiting the activation of glycogen synthase kinase-3β after phosphatidylinositol 3-kinase/protein kinase B signal activation, thereby activating Wnt1, β-catenin, and the expression of downstream neurogenic differentiation 1 and cyclin D1, which was comparable to Wnt/β-catenin signaling agonist 4,6-disubstituted pyrrolopyrimidine. We conclude that XQ-1H, after OGD/R damage to PC12 cells, may limit cell apoptosis in a Wnt/β-catenin signal-dependent manner, promoting cell proliferation and survival.

Effect of Wnt signaling pathway on neurogenesis after cerebral ischemia and its therapeutic potential

Neurogenesis process in the chronic phase of ischemic stroke has become the focus of research on stroke treatment recently, mainly through the activation of related pathways to increase the differentiation of neural stem cells (NSCs) in the brain sub-ventricular zone (SVZ) and subgranular zone (SGZ) of hippocampal dentate gyrus (DG) areas into neurons, promoting neurogenesis. While there is still debate about the longevity of active adult neurogenesis in humans, the SVZ and SGZ have the capacity to upregulate neurogenesis in response to cerebral ischemia, which opens discussion about potential treatment strategies to harness this neuronal regenerative response. Wnt signaling pathway is one of the most important approaches potentially targeting on neurogenesis after cerebral ischemia, appropriate activation of which in NSCs may help to improve the sequelae of cerebral ischemia. Various therapeutic approaches are explored on preclinical stage to target endogenous neurogenesis induced by Wnt signaling after stroke onset. This article describes the composition of Wnt signaling pathway and the process of neurogenesis after cerebral ischemia, and emphatically introduces the recent studies on the mechanisms of this pathway for post-stroke neurogenesis and the therapeutic possibility of activating the pathway to improve neurogenesis after stroke.

Endothelial to mesenchymal transition (EndMT) and vascular remodeling in pulmonary hypertension and idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible fibrotic disease associated with respiratory failure. The disease remains idiopathic, but repeated alveolar epithelium injury, disruption of alveolar-capillary integrity, abnormal vascular repair, and pulmonary vascular remodeling are considered possible pathogenic mechanisms. Also, the development of comorbidities such as pulmonary hypertension (PH) could further impact disease outcome, quality of life and survival rates in IPF.

AREAS COVERED

The current review provides a comprehensive literature survey of the mechanisms involved in the development and manifestations of IPF and their links to PH pathology. This review also provides the current understanding of molecular mechanisms that link the two pathologies and will specifically decipher the role of endothelial to mesenchymal transition (EndMT) along with the possible triggers of EndMT. The possibility of targeting EndMT as a therapeutic option in IPF is discussed.

EXPERT OPINION

With a steady increase in prevalence and mortality, IPF is no longer considered a rare disease. Thus, it is of utmost importance and urgency that the underlying profibrotic pathways and mechanisms are fully understood, to enable the development of novel therapeutic strategies.

The Platelet microRNA Profile of Kawasaki Disease: Identification of Novel Diagnostic Biomarkers

Challenging diagnosis and unknown etiology of Kawasaki disease (KD) increase the coronary artery lesions incidence. microRNAs (miRNAs) are the most promising biomarkers because of their stability in peripheral blood and noninvasive measurement procedure, whose potential utility have been proved in cancers. To explore the utility of differentially expressed (DE) miRNAs as early diagnostic markers, 44 patients (25 incomplete KD and 19 complete KD) and 31 febrile controls were recruited for small RNA sequencing. From all the 1922 expressed miRNA, 210 DE miRNAs were found between KD and febrile control groups. Though platelet miRNA profiles of complete KD incomplete KD were much similar through cluster analysis, the DE miRNAs were not identical. Eight DE miRNAs were validated by real-time quantitative PCR (qRT-PCR) in complete or incomplete KD groups using a normalizer, miR-126-3p, which was identified by geNorm and NormFinder tools. The expression level of miRNAs continuous changed over time was observed and the function analysis showed the potential role of miRNAs as therapeutic biomarkers. Additionally, the prediction model for KD showed a sensitivity of 78.8% and a specificity of 71.4%, respectively. This study used small RNA sequencing to identify miRNA biomarkers KD diagnosis based on a large sample size. Our findings shine a light on the understanding of molecular pathogenesis of KD and may improve the accuracy of KD diagnosis and prognosis in clinical.

Circulating miR-206 and Wnt-signaling are associated with cardiovascular complications and a history of preeclampsia in women

Women with a history of preeclampsia (PE) have increased risk of cardiovascular disease (CVD) later in life. However, the molecular determinants underlying this risk remain unclear. We sought to understand how circulating miRNA levels are affected by prior PE, and related to biological pathways underpinning cardiovascular disease. RNA sequencing was used to profile plasma levels of 2578 miRNAs in a retrospective study of women with a history of PE or normotensive pregnancy, in two independent cohorts with either acute coronary syndrome (ACS) (n = 17–18/group) or no ACS (n = 20/group). Differential miRNA alterations were assessed in relation to a history of PE (within each cohort) or ACS (across cohorts), and compared with miRNAs previously reported to be altered during PE. A history of PE was associated with altered levels of 30 and 20 miRNAs in the ACS and non-ACS cohorts, respectively, whereas ACS exposure was associated with alterations in 259 miRNAs. MiR-206 was identified at the intersection of all comparisons relating to past/current PE and ACS exposure, and has previously been implicated in atherogenic activities related to hepatocytes, vascular smooth muscle cells and macrophages. Integration of all differentially altered miRNAs with their predicted and experimentally validated targets in silico revealed a number of highly targeted genes with potential atherogenic functions (including NFAT5, CCND2 and SMAD2), and one significantly enriched KEGG biological pathway (Wnt signaling) that was shared between all exposure groups. The present study provides novel insights into miRNAs, target genes and biological pathways that may underlie the long-term cardiovascular sequelae of PE.

Low-Level Nanog Expression in the Regulation of Quiescent Endothelium

Supplemental Digital Content is available in the text.

Nanog is expressed in adult endothelial cells (ECs) at a low-level, however, its functional significance is not known. The goal of our study was to elucidate the role of Nanog in adult ECs using a genetically engineered mouse model system.

Merging microarray studies to identify a common gene expression signature to several structural heart diseases

BACKGROUND

Heart disease is the leading cause of death worldwide. Knowing a gene expression signature in heart disease can lead to the development of more efficient diagnosis and treatments that may prevent premature deaths. A large amount of microarray data is available in public repositories and can be used to identify differentially expressed genes. However, most of the microarray datasets are composed of a reduced number of samples and to obtain more reliable results, several datasets have to be merged, which is a challenging task. The identification of differentially expressed genes is commonly done using statistical methods. Nonetheless, these methods are based on the definition of an arbitrary threshold to select the differentially expressed genes and there is no consensus on the values that should be used.

RESULTS

Nine publicly available microarray datasets from studies of different heart diseases were merged to form a dataset composed of 689 samples and 8354 features. Subsequently, the adjusted p-value and fold change were determined and by combining a set of adjusted p-values cutoffs with a list of different fold change thresholds, 12 sets of differentially expressed genes were obtained. To select the set of differentially expressed genes that has the best accuracy in classifying samples from patients with heart diseases and samples from patients with no heart condition, the random forest algorithm was used. A set of 62 differentially expressed genes having a classification accuracy of approximately 95% was identified.

CONCLUSIONS

We identified a gene expression signature common to different cardiac diseases and supported our findings by showing their involvement in the pathophysiology of the heart. The approach used in this study is suitable for the identification of gene expression signatures, and can be extended to different diseases.

Role of Hippo-YAP1/TAZ pathway and its crosstalk in cardiac biology

The Hippo pathway undertakes a pivotal role in organ size control and the process of physiology and pathology in tissue. Its downstream effectors YAP1 and TAZ receive upstream stimuli and exert transcription activity to produce biological output. Studies have demonstrated that the Hippo pathway contributes to maintenance of cardiac homeostasis and occurrence of cardiac disease. And these cardiac biological events are affected by crosstalk among Hippo-YAP1/TAZ, Wnt/β-catenin, Bone morphogenetic protein (BMP) and G-protein-coupled receptor (GPCR) signaling, which provides new insights into the Hippo pathway in heart. This review delineates the interaction among Hippo, Wnt, BMP and GPCR pathways and discusses the effects of these pathways in cardiac biology.

Exogenous supplement of glucagon like peptide-1 protects the heart against aortic banding induced myocardial fibrosis and dysfunction through inhibiting mTOR/p70S6K signaling and promoting autophagy

Mammalian target of rapamycin (mTOR) and a ribosomal protein S6 kinase (p70S6K) mediate tissue fibrosis and negatively regulate autophagy. This study aims to investigate whether glucagon-like peptide-1 (GLP-1) analog liraglutide protects the heart against aortic banding-induced cardiac fibrosis and dysfunction through inhibiting mTOR/p70S6K signaling and promoting autophagy activity. Male SD rats were randomly divided into four groups (n = 6/each group): sham operated control; abdominal aortic constriction (AAC); liraglutide treatment during AAC (0.3 mg/kg, injected subcutaneously twice daily); rapamycin treatment during AAC (0.2 mg/kg/day, administered by gastric gavage). Relative to the animals with AAC on week 16, liraglutide treatment significantly reduced heart/body weight ratio, inhibited cardiomyocyte hypertrophy, and augmented plasma GLP-1 level and tissue GLP-1 receptor expression. Phosphorylation of mTOR/p70S6K, populations of myofibroblasts and synthesis of collagen I/III in the myocardium were simultaneously inhibited. Furthermore, autophagy regulating proteins: LC3-II/LC3-I ratio and Beclin-1 were upregulated, and p62 was downregulated by liraglutide. Compared with liraglutide group, treatment with rapamycin, a specific inhibitor of mTOR, compatibly augmented GLP-1 receptor level, inhibited phosphorylation of mTOR/p70S6K and expression of p62 as well as increased level of LC3-II/LC3-I ratio and Beclin-1, suggesting that there is an interaction between GLP-1 and mTOR/p70S6K signaling in the regulation of autophagy. In line with these modifications, treatment with liraglutide and rapamycin significantly reduced perivascular/interstitial fibrosis, and preserved systolic/diastolic function. These results suggest that the inhibitory effects of liraglutide on cardiac fibrosis and dysfunction are potentially mediated by inhibiting mTOR/p70S6K signaling and enhancing autophagy activity.

Wnt signaling pathway in aging-related tissue fibrosis and therapies

Fibrosis is the final hallmark of pathological remodeling, which is a major contributor to the pathogenesis of various chronic diseases and aging-related organ failure to fully control chronic wound-healing and restoring tissue function. The process of fibrosis is involved in the pathogenesis of the kidney, lung, liver, heart and other tissue disorders. Wnt is a highly conserved signaling in the aberrant wound repair and fibrogenesis, and sustained Wnt activation is correlated with the pathogenesis of fibrosis. In particular, mounting evidence has revealed that Wnt signaling played important roles in cell fate determination, proliferation and cell polarity establishment. The expression and distribution of Wnt signaling in different tissues vary with age, and these changes have key effects on maintaining tissue homeostasis. In this review, we first describe the major constituents of the Wnt signaling and their regulation functions. Subsequently, we summarize the dysregulation of Wnt signaling in aging-related fibrotic tissues such as kidney, liver, lung and cardiac fibrosis, followed by a detailed discussion of its involvement in organ fibrosis. In addition, the crosstalk between Wnt signaling and other pathways has the potential to profoundly add to the complexity of organ fibrosis. Increasing studies have demonstrated that a number of Wnt inhibitors had the potential role against tissue fibrosis, specifically in kidney fibrosis and the implications of Wnt signaling in aging-related diseases. Therefore, targeting Wnt signaling might be a novel and promising therapeutic strategy against aging-related tissue fibrosis.

Single-molecule dynamics of Dishevelled at the plasma membrane and Wnt pathway activation

Canonical Wnt signaling is one of the most important and widely distributed pathways in metazoan development. Dishevelled is thought to serve as an essential bridge between the membrane receptors and downstream signaling components, which has the tendency to aggregate in vitro and to form large aggregates of dubious significance in vivo, when overexpressed. To obtain a molecular understanding of the role of Dvl in Wnt signaling, while circumventing these aggregation problems, we have expressed a fluorescent-tagged Dishevelled in cells at its physiological concentration and quantified the size distribution of Dishevelled before and after Wnt treatment. We found that limited oligomerization in response to the Wnt ligand is very dynamic and provides a key step in signal transduction.

Dvl (Dishevelled) is one of several essential nonenzymatic components of the Wnt signaling pathway. In most current models, Dvl forms complexes with Wnt ligand receptors, Fzd and LRP5/6 at the plasma membrane, which then recruits the destruction complex, eventually leading to inactivation of β-catenin degradation. Although this model is widespread, direct evidence for the individual steps is lacking. In this study, we tagged mEGFP to C terminus of dishevelled2 gene using CRISPR/Cas9-induced homologous recombination and observed its dynamics directly at the single-molecule level with total internal reflection fluorescence (TIRF) microscopy. We focused on two questions: 1) What is the native size and what are the dynamic features of membrane-bound Dvl complexes during Wnt pathway activation? 2) What controls the behavior of these complexes? We found that membrane-bound Dvl2 is predominantly monomer in the absence of Wnt (observed mean size 1.1). Wnt3a stimulation leads to an increase in the total concentration of membrane-bound Dvl2 from 0.12/μm² to 0.54/μm². Wnt3a also leads to increased oligomerization which raises the weighted mean size of Dvl2 complexes to 1.5, with 56.1% of Dvl still as monomers. The driving force for Dvl2 oligomerization is the increased concentration of membrane Dvl2 caused by increased affinity of Dvl2 for Fzd, which is independent of LRP5/6. The oligomerized Dvl2 complexes have increased dwell time, 2 ∼ 3 min, compared to less than 1 s for monomeric Dvl2. These properties make Dvl a unique scaffold, dynamically changing its state of assembly and stability at the membrane in response to Wnt ligands.

A Systematic Review of WNT Signaling in Endothelial Cell Oligodendrocyte Interactions: Potential Relevance to Cerebral Small Vessel Disease

Key pathological features of cerebral small vessel disease (cSVD) include impairment of the blood brain barrier (BBB) and the progression of white matter lesions (WMLs) amongst other structural lesions, leading to the clinical manifestations of cSVD. The function of endothelial cells (ECs) is of major importance to maintain a proper BBB. ECs interact with several cell types to provide structural and functional support to the brain. Oligodendrocytes (OLs) myelinate axons in the central nervous system and are crucial in sustaining the integrity of white matter. The interplay between ECs and OLs and their precursor cells (OPCs) has received limited attention yet seems of relevance for the study of BBB dysfunction and white matter injury in cSVD. Emerging evidence shows a crosstalk between ECs and OPCs/OLs, mediated by signaling through the Wingless and Int-1 (WNT)/β-catenin pathway. As the latter is involved in EC function (e.g., angiogenesis) and oligodendrogenesis, we reviewed the role of WNT/β-catenin signaling for both cell types and performed a systematic search to identify studies describing a WNT-mediated interplay between ECs and OPCs/OLs. Dysregulation of this interaction may limit remyelination of WMLs and render the BBB leaky, thereby initiating a vicious neuroinflammatory cycle. A better understanding of the role of this signaling pathway in EC-OL crosstalk is essential in understanding cSVD development.

Enhanced Generation of Induced Cardiomyocytes Using a Small-Molecule Cocktail to Overcome Barriers to Cardiac Cellular Reprogramming

Background

Given known inefficiencies in reprogramming of fibroblasts into mature induced cardiomyocytes (iCMs), we sought to identify small molecules that would overcome these barriers to cardiac cell transdifferentiation.

Methods and Results

We screened alternative combinations of compounds known to impact cell reprogramming using morphologic and functional cell differentiation assays in vitro. After screening 6 putative reprogramming factors, we found that a combination of the histone deacetylase inhibitor sodium butyrate, the WNT inhibitor ICG‐001, and the cardiac growth regulator retinoic acid (RA) maximally enhanced iCM generation from primary rat cardiac fibroblasts when combined with administration of the cardiodifferentiating transcription factors Gata4, Mef2C, and Tbx5 (GMT) compared with GMT administration alone (23±1.5% versus 3.3±0.2%; P<0.0001). Expression of the cardiac markers cardiac troponin T, Myh6, and Nkx2.5 was upregulated as early as 10 days after GMT–sodium butyrate, ICG‐001, and RA treatment. Human iCM generation was likewise enhanced when administration of the human cardiac reprogramming factors GMT, Hand2, and Myocardin plus miR‐590 was combined with sodium butyrate, ICG‐001, and RA compared with GMT, Hand2, and Myocardin plus miR‐590 treatment alone (25±1.3% versus 5.7±0.4%; P<0.0001). Rat and human iCMs also more frequently demonstrated spontaneous beating in coculture with neonatal cardiomyocytes with the addition of sodium butyrate, ICG‐001, and RA to transcription factor cocktails compared with transcription factor treatment alone.

Conclusions

The combined administration of histone deacetylase and WNT inhibitors with RA enhances rat and human iCM generation induced by transcription factor administration alone. These findings suggest opportunities for improved translational approaches for cardiac regeneration.

Bone mineral density and mortality in end-stage renal disease patients

Osteoporosis characterized by low bone mineral density (BMD) as assessed by dual-energy X-ray absorptiometry (DXA) is common among end-stage renal disease (ESRD) patients and associates with high fracture incidence and high all-cause mortality. This is because chronic kidney disease-mineral bone disorders (CKD-MBDs) promote not only bone disease (osteoporosis and renal dystrophy) but also vascular calcification and cardiovascular disease. The disturbed bone metabolism in ESRD leads to 'loss of cortical bone' with increased cortical porosity and thinning of cortical bone rather than to loss of trabecular bone. Low BMD, especially at cortical-rich bone sites, is closely linked to CKD-MBD, vascular calcification and poor cardiovascular outcomes. These effects appear to be largely mediated by shared mechanistic pathways via the 'bone-vascular axis' through which impaired bone status associates with changes in the vascular wall. Thus, bone is more than just the scaffolding that holds the body together and protects organs from external forces but is-in addition to its physical supportive function-also an active endocrine organ that interacts with the vasculature by paracrine and endocrine factors through pathways including Wnt signalling, osteoprotegerin (OPG)/receptor activator of nuclear factor-κB (RANK)/RANK ligand system and the Galectin-3/receptor of advanced glycation end products axis. The insight that osteogenesis and vascular calcification share many similarities-and the knowledge that vascular calcification is a cell-mediated active rather than a passive mineralization process-suggest that low BMD and vascular calcification ('vascular ossification') to a large extent represent two sides of the same coin. Here, we briefly review changes of BMD in ESRD as observed using different DXA methods (central and whole-body DXA) at different bone sites for BMD measurements, and summarize recent knowledge regarding the relationships between 'low BMD' and 'fracture incidence, vascular calcification and increased mortality' in ESRD patients, as well as potential 'molecular mechanisms' underlying these associations.

Drug repurposing studies of PARP inhibitors as a new therapy for inherited retinal degeneration

The enzyme poly-ADP-ribose-polymerase (PARP) has important roles for many forms of DNA repair and it also participates in transcription, chromatin remodeling and cell death signaling. Currently, some PARP inhibitors are approved for cancer therapy, by means of canceling DNA repair processes and cell division. Drug repurposing is a new and attractive aspect of therapy development that could offer low-cost and accelerated establishment of new treatment options. Excessive PARP activity is also involved in neurodegenerative diseases including the currently untreatable and blinding retinitis pigmentosa group of inherited retinal photoreceptor degenerations. Hence, repurposing of known PARP inhibitors for patients with non-oncological diseases might provide a facilitated route for a novel retinitis pigmentosa therapy. Here, we demonstrate and compare the efficacy of two different PARP inhibitors, BMN-673 and 3-aminobenzamide, by using a well-established retinitis pigmentosa model, the rd1 mouse. Moreover, the mechanistic aspects of the PARP inhibitor-induced protection were also investigated in the present study. Our results showed that rd1 rod photoreceptor cell death was decreased by about 25-40% together with the application of these two PARP inhibitors. The wealth of human clinical data available for BMN-673 highlights a strong potential for a rapid clinical translation into novel retinitis pigmentosa treatments. Remarkably, we have found that the efficacy of 3 aminobenzamide was able to decrease PARylation at the nanomolar level. Our data also provide a link between PARP activity with the Wnt/β-catenin pathway and the major intracellular antioxidant concentrations behind the PARP-dependent retinal degeneration. In addition, molecular modeling studies were integrated with experimental studies for better understanding of the role of PARP1 inhibitors in retinal degeneration.

Aberrant canonical Wnt signaling: Phytochemical based modulation

BACKGROUND

Wnt signaling pathway plays a major role during development like gastrulation, axis formation, organ development and organization of body plan development. Wnt signaling aberration has been linked with various disease conditions like osteoporosis, colon cancer, hair follicle tumor, Leukemia, and Alzheimer's disease. Phytochemicals like flavonoid, glycosides, polyphenols, have been reported to directly target the markers of Wnt signaling in different disease models.

PURPOSE

The study deals in detail about the different phytochemical targeting key players of Wnt signaling pathway in diseases like Cancer, Osteoporosis, and Alzheimer's disease. We have focused on the Pharmacological basis of disease alleviation by phytochemical specifically targeting the Wnt signaling markers in this study.

METHODS

The study focused on the published articles from the preclinical rodent and invitro cell line studies related to Wnt signaling and Phytochemicals related to Cancer, Alzheimer's and Osteoporosis. The electronic databases Scopus, Web of Science and Pubmed database were used for the systematic search of literatures from 2005 up to 2019 using keywords Canonical Wnt signaling pathway, Cancer, Alzheimer's disease, Osteoporosis, Phytochemicals. The focus was to identify the target specific modulation of Wnt signaling mediated by phytochemicals.

RESULTS

Approximately 30 phytochemicals of different class have been identified to modulate Wnt signaling pathway acting through Axin, β-catenin translocation, GSK-3β, AKT, Wif-1 in various experimental studies. The down regulation of Wnt signaling is observed in Cancer mostly colorectal cancer, breast cancer mediated through mutations in APC and Axin genes. Different class of Phytochemicals such as flavonoid, glycosides, polyphenol, alkaloids etc. have been found to target Wnt signaling markers and alleviate Cancer. Similarly, Up regulation of Wnt signaling has been reported in Osteoporosis and neurodegenerative disease like Alzheimer's disease.

CONCLUSION

This review highlights the possibility of the Phytochemicals to target Wnt markers and its potential to either activate or deactivate the Wnt signaling pathway. It also describes the challenges in proper targeting of Wnt signaling and the potential risk and consequences of either up regulation or down regulation of the signaling pathway. This article highlights the possibility of Wnt signaling pathway as a therapeutic option in different diseases.

Identification of candidate lncRNAs and circRNAs regulating WNT3/β-catenin signaling in essential hypertension

Mounting evidence suggests that noncoding RNAs (ncRNAs) contribute to the pathogenesis of cardiovascular diseases. However, their role in essential hypertension (EH) is still unclear. We therefore identified differentially expressed long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in EH patients from a high-risk population group and constructed a competing endogenous RNA regulatory network that predicts interactions of potential diagnostic and therapeutic relevance between specific lncRNA/circRNA-microRNA-mRNA triplets. Our analysis identified two lncRNAs, transmembrane protein 183A pseudogene (LOC646616) and leucine aminopeptidase 3 pseudogene 2 (LAP3P2), and two circRNAs, hsa_circ_0039388 and hsa_circ_0038648, that are highly co-expressed with both wingless-type MMTV integration site family member 3 (WNT3) and calcium/calmodulin-dependent protein kinase II inhibitor 2 (CAMK2N2) mRNAs and also share common microRNA binding sites with these two transcripts. We also confirmed that a mutually regulated network composed of LOC646616/microRNA-637/WNT3 controls WNT3 expression and influences viability and invasive properties in human arterial smooth muscle cells in vitro. These findings highlight a novel ncRNA-based regulatory mechanism potentially driving WNT/β-catenin activation in EH, and suggest that the identified ncRNAs may represent useful biomarkers and therapeutic targets for this condition.

Cleavage of Desmosomal Cadherins Promotes γ-Catenin Degradation and Benefits Wnt Signaling in Coxsackievirus B3-Induced Destruction of Cardiomyocytes

Coxsackievirus B3 (CVB3) is the primary etiologic agent of viral myocarditis, a major heart disease that occurs predominantly in children and young adolescents. In the heart, intercalated disks (ICD) are important structural formations that connect adjacent cardiomyocytes to maintain cardiac architecture and mediate signal communication. Deficiency in ICD components, such as desmosome proteins, leads to heart dysfunction. γ-catenin, a component protein of desmosomes, normally binds directly to desmocollin-2 and desmoglein-2. In this study, we found that CVB3 infection downregulated γ-catenin at the protein level but not the mRNA level in mouse HL-1 cardiomyocytes. We further found that this reduction of γ-catenin protein is a result of ubiquitin proteasome-mediated degradation, since the addition of proteasome inhibitor MG132 inhibited γ-catenin downregulation. In addition, we found that desmocollin-2 and desmoglein-2 were cleaved by both viral protease 3C and virus-activated cellular caspase, respectively. These cleavages led to the release of bound γ-catenin from the desmosome into the cytosol, resulting in rapid degradation of γ-catenin. Since γ-catenin shares high sequence homology with β-catenin in binding the TCF/LEF transcription factor, we further studied the effect of γ-catenin degradation on Wnt/β-catenin signaling. Luciferase assay showed that γ-catenin expression inhibited Wnt/β-catenin signaling. This finding was substantiated by qPCR to show that overexpression of γ-catenin downregulated transcription of Wnt signal target genes, c-myc and MMP9, while silencing γ-catenin upregulated these target genes. Finally, we demonstrated that γ-catenin expression inhibited CVB3 replication. In search for the underlying mechanism, we found that silencing γ-catenin caused down-regulation of interferon-β and its stimulated antiviral genes MDA5, MAVS, and ISG15. Taken together, our results indicate, for the first time, that CVB3 infection causes cardiomyocyte death through, at least in part, direct damage to the desmosome structure and reduction of γ-catenin protein, which in return promotes Wnt/β-catenin signaling and downregulates interferon-β stimulated immune responses.

Exogenous spermine attenuates myocardial fibrosis in diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress and the canonical Wnt signaling pathway

Myocardial fibrosis is one of the main pathological manifestations of diabetic cardiomyopathy (DCM). Spermine (SPM), a product of polyamine metabolism, plays an important role in many cardiac diseases including hypertrophy, ischemia, and infarction, but its role in diabetic myocardial fibrosis has not been clarified. This study aimed to investigate the role of polyamine metabolism, specifically SPM, in diabetic myocardial fibrosis and to explore the related mechanisms. We used intraperitoneal injection of streptozotocin (STZ, 60 mg/kg) in Wistar rats and high glucose (HG, 40 mM) stimulated cardiac fibroblasts (CFs) to established a type 1 diabetes (T1D) model in vivo and in vitro, which were pretreated with exogenous SPM (5 mg/kg per day and 5 μM). The results showed that hyperglycemia induced the expression of the key polyamine synthesis enzyme ornithine decarboxylase (ODC) decreased and the key catabolic enzyme spermidine/spermine N¹ -acetyltransferase (SSAT) increased compared with those in the control group. The body weight, blood insulin level, and cardiac ejection function were decreased, while blood glucose, heart weight, the ratio of heart weight to body weight, myocardial interstitial collagen deposition, and endoplasmic reticulum stress (ERS)-related protein (glucose-regulated protein-78, glucose-regulated protein-94, activating transcription factor-4, and C/EBP homology protein) expression in the T1D group were all significantly increased. HG also caused an increased expression of Wnt3, β-catenin (in cytoplasm and nucleus), while Axin2 and phosphorylated β-catenin decreased. Exogenous SPM improved the above changes caused by polyamine metabolic disorders. In conclusion, polyamine metabolism disorder occurs in the myocardial tissue of diabetic rats, causing myocardial fibrosis and ERS. Exogenous SPM plays a myocardial protective role via inhibiting of ERS and the canonical Wnt/β-catenin signaling pathway.

Pathophysiological and Genetic Aspects of Vascular Calcification

Recent evidence suggests that vascular calcification is an independent cardiovascular risk factor (CRF) of morbidity and mortality. New studies point out the existence of a complex physiopathological mechanism that involves inflammation, oxidation, the release of chemical mediators, and genetic factors that promote the osteochondrogenic differentiation of vascular smooth muscle cells (VSMC). This review will evaluate the main mechanisms involved in the pathophysiology and genetics modulation of the process of vascular calcification. Objective. A systematic review of the pathophysiology factors involved in vascular calcification and its genetic influence was performed. Methods. A systematic review was conducted in the Medline and PubMed databases and were searched for studies concerning vascular calcification using the keywords and studies published until 2020/01 in English. Inclusion Criteria. Studies in vitro, animal models, and humans. These include cohort (both retrospective and prospective cohort studies), case-control, cross-sectional, and systematic reviews. Exclusion Criteria. Studies before 2003 of the existing literature.

Klotho/FGF23 and Wnt Signaling as Important Players in the Comorbidities Associated with Chronic Kidney Disease

Fibroblast Growth Factor 23 (FGF23) and Klotho play an essential role in the regulation of mineral metabolism, and both are altered as a consequence of renal failure. FGF23 increases to augment phosphaturia, which prevents phosphate accumulation at the early stages of chronic kidney disease (CKD). This effect of FGF23 requires the presence of Klotho in the renal tubules. However, Klotho expression is reduced as soon as renal function is starting to fail to generate a state of FGF23 resistance. Changes in these proteins directly affect to other mineral metabolism parameters; they may affect renal function and can produce damage in other organs such as bone, heart, or vessels. Some of the mechanisms responsible for the changes in FGF23 and Klotho levels are related to modifications in the Wnt signaling. This review examines the link between FGF23/Klotho and Wnt/β-catenin in different organs: kidney, heart, and bone. Activation of the canonical Wnt signaling produces changes in FGF23 and Klotho and vice versa; therefore, this pathway emerges as a potential therapeutic target that may help to prevent CKD-associated complications.

Associations of Serum Dickkopf-1 and Sclerostin With Cardiovascular Events: Results From the Prospective Bruneck Study

Background Dickkopf-1 and sclerostin have been implicated in atherosclerosis and vascular calcification. We aimed to quantify the association of their serum levels with incident cardiovascular disease (CVD) in the general population. Methods and Results Among 706 participants of the prospective, population-based Bruneck Study, mean±SD of serum levels were 44.5±14.7 pmol/L for dickkopf-1 and 47.1±17.5 pmol/L for sclerostin. The primary outcome was a composite CVD end point composed of ischemic or hemorrhagic stroke, transient ischemic attack, myocardial infarction, angina pectoris, peripheral vascular disease, and revascularization procedures. Over a median follow-up duration of 15.6 years, 179 CVD events occurred. For the primary CVD outcome, multivariable-adjusted hazard ratios (HRs) per SD higher level were 1.20 for dickkopf-1 (95% CI, 1.02-1.42; P=0.028) and 0.92 for sclerostin (95% CI, 0.78-1.08; P=0.286). Secondary outcome analyses revealed that the association of dickkopf-1 was primarily driven by ischemic and hemorrhagic stroke (67 events; HR, 1.37; 95% CI, 1.06-1.78; P=0.017), whereas no increase in risk was observed for transient ischemic attack (22 events; HR, 0.87; 95% CI, 0.53-1.44; P=0.593), myocardial infarction (45 events; HR, 1.10; 95% CI, 0.78-1.54; P=0.598), or for other CVD (45 events; HR, 1.25; 95% CI, 0.88-1.76; P=0.209). Conclusions In this prospective, population-based study, elevated baseline levels of dickkopf-1, but not sclerostin, were independently associated with incident cardiovascular events, which was mainly driven by stroke. Our findings support the hypothesis of a role of dickkopf-1 in the pathogenesis of CVD.

Sirtuin-1 and Its Relevance in Vascular Calcification

Vascular calcification (VC) is highly associated with cardiovascular disease and all-cause mortality in patients with chronic kidney disease. Dysregulation of endothelial cells and vascular smooth muscle cells (VSMCs) is related to VC. Sirtuin-1 (Sirt1) deacetylase encompasses a broad range of transcription factors that are linked to an extended lifespan. Sirt1 enhances endothelial NO synthase and upregulates FoxOs to activate its antioxidant properties and delay cell senescence. Sirt1 reverses osteogenic phenotypic transdifferentiation by influencing RUNX2 expression in VSMCs. Low Sirt1 hardly prevents acetylation by p300 and phosphorylation of β-catenin that, following the facilitation of β-catenin translocation, drives osteogenic phenotypic transdifferentiation. Hyperphosphatemia induces VC by osteogenic conversion, apoptosis, and senescence of VSMCs through the Pit-1 cotransporter, which can be retarded by the sirt1 activator resveratrol. Proinflammatory adipocytokines released from dysfunctional perivascular adipose tissue (PVAT) mediate medial calcification and arterial stiffness. Sirt1 ameliorates release of PVAT adipokines and increases adiponectin secretion, which interact with FoxO 1 against oxidative stress and inflammatory arterial insult. Conclusively, Sirt1 decelerates VC by means of influencing endothelial NO bioavailability, senescence of ECs and VSMCs, osteogenic phenotypic transdifferentiation, apoptosis of VSMCs, ECM deposition, and the inflammatory response of PVAT. Factors that aggravate VC include vitamin D deficiency-related macrophage recruitment and further inflammation responses. Supplementation with vitamin D to adequate levels is beneficial in improving PVAT macrophage infiltration and local inflammation, which further prevents VC.

Cardiac-Specific Overexpression of Catalytically Inactive Corin Reduces Edema, Contractile Dysfunction, and Death in Mice with Dilated Cardiomyopathy

Humans with dilated cardiomyopathy (DCM) and heart failure (HF) develop low levels of corin, a multi-domain, cardiac-selective serine protease involved in natriuretic peptide cleavage and sodium and water regulation. However, experimental restoration of corin levels markedly attenuates HF progression. To determine whether the beneficial effects of corin in HF require catalytic activity, we engineered cardiac overexpression of an enzymatically inactive corin transgene (corin-Tg(i)). On a wild-type (WT) background, corin-Tg(i) had no evident phenotypic effects. However, in a well-established genetic model of DCM, corin-Tg(i)/DCM mice had increased survival (p < 0.01 to 0.001) vs. littermate corin-WT/DCM controls. Pleural effusion (p < 0.01), lung edema (p < 0.05), systemic extracellular free water (p < 0.01), and heart weight were decreased (p < 0.01) in corin-Tg(i)/DCM vs. corin-WT/DCM mice. Cardiac ejection fraction and fractional shortening improved (p < 0.01), while ventricular dilation decreased (p < 0.0001) in corin-Tg(i)/DCM mice. Plasma atrial natriuretic peptide, cyclic guanosine monophosphate, and neprilysin were significantly decreased. Cardiac phosphorylated glycogen synthase kinase-3β (pSer9-GSK3β) levels were increased in corin(i)-Tg/DCM mice (p < 0.01). In summary, catalytically inactive corin-Tg(i) decreased fluid retention, improved contractile function, decreased HF biomarkers, and diminished cardiac GSK3β activity. Thus, the protective effects of cardiac corin on HF progression and survival in experimental DCM do not require the serine protease activity of the molecule.