RTEF-1 Inhibits Vascular Smooth Muscle Cell Calcification through Regulating Wnt/β-Catenin Signaling Pathway

Pathogenesis and Mechanism of Uremic Vascular Calcification

This review elucidates the modeling and mechanistic studies of vascular calcification in chronic kidney disease - mineral and bone disorder. In patients with chronic kidney disease, metabolic abnormalities in uremic toxins, including phosphate and indole sulfate, are closely associated with vascular calcification. Vitamin K, vascular circadian clock, and autophagy are also key factors involved in vascular calcification. Furthermore, communication between endothelial cells and smooth muscle cells also plays a pivotal role in the regulation of this process. Together, these factors accelerate vascular calcification progression and increase the risk of cardiovascular events. Therefore, timely intervention for vascular calcification is essential for patients with chronic kidney disease.

Substrate stiffness promotes vascular smooth muscle cell calcification by reducing the levels of nuclear actin monomers

BACKGROUND

Vascular calcification (VC) is a prevalent independent risk factor for adverse cardiovascular events and is associated with diabetes, hypertension, chronic kidney disease, and atherosclerosis. However, the mechanisms regulating the osteogenic differentiation of vascular smooth muscle cells (VSMC) are not fully understood.

METHODS

Using hydrogels of tuneable stiffness and lysyl oxidase-mediated stiffening of human saphenous vein ex vivo, we investigated the role of substrate stiffness in the regulation of VSMC calcification.

RESULTS

We demonstrate that increased substrate stiffness enhances VSMC osteogenic differentiation and VSMC calcification. We show that the effects of substrate stiffness are mediated via a reduction in the level of actin monomer within the nucleus. We show that in cells interacting with soft substrate, elevated levels of nuclear actin monomer repress osteogenic differentiation and calcification by repressing YAP-mediated activation of both TEA Domain transcription factor (TEAD) and RUNX Family Transcription factor 2 (RUNX2).

CONCLUSION

This work highlights for the first time the role of nuclear actin in mediating substrate stiffness-dependent VSMC calcification and the dual role of YAP-TEAD and YAP-RUNX2 transcriptional complexes.

Vascular calcification and cellular signaling pathways as potential therapeutic targets

Increased vascular calcification (VC) is observed in patients with cardiovascular diseases such as atherosclerosis, diabetes, and chronic kidney disease. VC is divided into three types according to its location: intimal, medial, and valvular. Various cellular signaling pathways are associated with VC, including the Wnt, mitogen-activated protein kinase, phosphatidylinositol-3 kinase/Akt, cyclic nucleotide-dependent protein kinase, protein kinase C, calcium/calmodulin-dependent kinase II, adenosine monophosphate-activated protein kinase/mammalian target of rapamycin, Ras homologous GTPase, apoptosis, Notch, and cytokine signaling pathways. In this review, we discuss the literature concerning the key cellular signaling pathways associated with VC and their role as potential therapeutic targets. Inhibitors to these pathways represent good candidates for use as potential therapeutic agents for the prevention and treatment of VC.

Lumican silencing ameliorates β-glycerophosphate-mediated vascular smooth muscle cell calcification by attenuating the inhibition of APOB on KIF2C activity

Adverse cardiovascular events are associated with vascular calcification (VC) process, where vascular smooth muscle cells (VSMCs) differentiate into osteoblastic phenotype and deposit hydroxyapatite crystals. Microtubule-associated protein kinesin family member 2C (KIF2C) expression is decreased obviously in VSMC during calcification induction. Accordingly, we investigate the role and potential mechanism of KIF2C on VSMC calcification. The effects of β-glycerophosphate (β-GP)/KIF2C/lumican (LUM) on calcification, calcium content, alkaline phosphatase (ALP) activity, calcification-related markers, Tubulin, the ratio of polymerized (Po) to free (Fr) tubulin, as well as levels of LUM, apolipoprotein B (APOB), and KIF2C were assessed by Alizarin red S staining, calcium assay kit, ALP assay kit, Western blot, immunofluorescence, and quantitative real-time PCR. The interplay between LUM and APOB was estimated using co-immunoprecipitation and immunofluorescence. As a result, β-GP promoted calcification of human VMSCs (HVMSCs) and repressed KIF2C expression. KIF2C overexpression reversed the effect of β-GP on HVSMCs. LUM silencing attenuated β-GP-induced promotion on HVSMC calcification and increased KIF2C expression by interacting with APOB. Collectively, LUM silencing can alleviate β-GP-induced VSMC calcification through mitigating the repression of APOB on KIF2C expression.

The association between visceral adiposity index and decreased renal function: A population-based study

Aims

We aimed to investigate the association of visceral adiposity index (VAI) with decreased renal function in US adults.

Design and methods

Cross-sectional data were analyzed for 35,018 adults in the National Health and Nutrition Examination Survey (NHANES) 2005–2018. VAI was determined using waist circumference, body mass index (BMI), triglycerides (TGs) and high-density lipoprotein-cholesterol. Albuminuria was defined as urinary albumin-to-creatinine ratio (ACR) >30 mg/g. A low estimated-glomerular filtration rate (eGFR) was defined as an eGFR lower than 60 ml/min/1.73 m2. Chronic kidney disease (CKD) was defined as either albuminuria or low-eGFR. A multivariable logistic regression analysis was utilized to explore the relationship of VAI with albuminuria, low-eGFR and CKD. Subgroup analysis and interaction tests were also conducted.

Results

A total of 35,018 participants were enrolled with albuminuria, low-eGFR, and CKD prevalence rates of 5.18, 6.42, and 10.62%, respectively, which increased with the higher VAI tertiles. After full adjustment, a positive association of VAI with albuminuria (OR = 1.03, 95% CI: 1.00, 1.06) and CKD (OR = 1.04, 95% CI: 1.02, 1.06) was observed. Participants in the highest VAI tertile had a significantly 30% increased risk for albuminuria (OR = 1.30, 95% CI: 1.07, 1.58) and a 27% increased risk for CKD (OR = 1.27, 95% CI: 1.08, 1.49) compared with those in the lowest VAI tertile. No statistically significant association between VAI and low-eGFR was detected. Subgroup analysis and the interaction term indicated that there was no significant difference among different stratifications.

Conclusion

Visceral adiposity accumulation evaluating by VAI was associated with increased likelihood of the decline in renal function.

Elastic Fibers and F-Box and WD-40 Domain-Containing Protein 2 in Bovine Periosteum and Blood Vessels

Elastic fibers form vessel walls, and elastic fiber calcification causes serious vascular diseases. Elastin is a well-known elastic fiber component; however, the insoluble nature of elastic fibers renders elastic fiber component analysis difficult. A previous study investigated F-box and WD-40 domain-containing protein 2 (FBXW2) in the cambium layer of bovine periosteum and hypothesized that fiber structures of FBXW2 are coated with osteocalcin during explant culture. Here, FBXW2 was expressed around some endothelial cells but not in all microvessels of the bovine periosteum. The author hypothesized that FBXW2 is expressed only in blood vessels with elastic fibers. Immunostaining and Elastica van Gieson staining indicated that FBXW2 was expressed in the same regions as elastic fibers and elastin in the cambium layer of the periosteum. Alpha-smooth muscle actin (αSMA) was expressed in microvessels and periosteum-derived cells. Immunostaining and observation of microvessels with serial sections revealed that osteocalcin was not expressed around blood vessels at 6 and 7 weeks. However, blood vessels and periosteum connoted elastic fibers, FBXW2, and αSMA. These findings are expected to clarify the processes involved in the calcification of elastic fibers in blood vessels.

Hsa_circRNA_0008028 Deficiency Ameliorates High Glucose-Induced Proliferation, Calcification, and Autophagy of Vascular Smooth Muscle Cells via miR-182-5p/TRIB3 Axis

Background

It is well-known that dysfunctions of vascular smooth muscle cells (VSMCs) act an essential part in vascular complications of diabetes. Studies have shown that circular RNAs (circRNAs) and microRNAs (miRNAs) play a crucial role in regulating cell functions. However, their influence on the proliferation, calcification, and autophagy of VSMCs remains to be further explored. Therefore, this study elucidates the role and mechanism of hsa_circRNA_0008028 in high glucose- (HG-, 30 mM) treated VSMCs in vitro.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was chosen to detect the levels of hsa_circRNA_0008028, miR-182-5p, and tribble 3 (TRIB3). Then, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to predict and verify the binding relationship between miR-182-5p and hsa_circRNA_0008028 or TRIB3. Cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, corresponding commercial kits, and western blotting were used to measure indexes reflecting cell viability, proliferation, calcification, and autophagy of VSMCs, respectively.

Results

In HG-induced VSMCs, hsa_circRNA_0008028 and TRIB3 were highly expressed, whereas miR-182-5p decreased. Meanwhile, cell proliferation, calcification, and autophagy could be repressed by silencing of hsa_circRNA_0008028. However, these effects can be eliminated by miR-182-5p inhibition. Furthermore, it was demonstrated that hsa_circRNA_0008028 could promote the expression of TRIB3, a target of miR-182-5p, by directly sponging miR-182-5p. The expression of TRIB3 was suppressed by hsa_circRNA_0008028 knockout, which was rescued by miR-182-5p inhibition.

Conclusion

This study reveals that hsa_circRNA_0008028 can act as a sponge of miR-182-5p and promote HG-induced proliferation, calcification, and autophagy of VSMCs partly by regulating TRIB3.

Identification of potential biomarkers of vascular calcification using bioinformatics analysis and validation in vivo

Background

Vascular calcification (VC) is the most widespread pathological change in diseases of the vascular system. However, we know poorly about the molecular mechanisms and effective therapeutic approaches of VC.

Methods

The VC dataset, GSE146638, was downloaded from the Gene Expression Omnibus (GEO) database. Using the edgeR package to screen Differentially expressed genes (DEGs). Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were used to find pathways affecting VC. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed on the DEGs. Meanwhile, using the String database and Cytoscape software to construct protein-protein interaction (PPI) networks and identify hub genes with the highest module scores. Correlation analysis was performed for hub genes. Receiver operating characteristic (ROC) curves, expression level analysis, GSEA, and subcellular localization were performed for each hub gene. Expression of hub genes in normal and calcified vascular tissues was verified by quantitative reverse transcription PCR (RT-qPCR) and immunohistochemistry (IHC) experiments. The hub gene-related miRNA-mRNA and TF-mRNA networks were constructed and functionally enriched for analysis. Finally, the DGIdb database was utilized to search for alternative drugs targeting VC hub genes.

Results

By comparing the genes with normal vessels, there were 64 DEGs in mildly calcified vessels and 650 DEGs in severely calcified vessels. Spp1, Sost, Col1a1, Fn1, and Ibsp were central in the progression of the entire VC by the MCODE plug-in. These hub genes are primarily enriched in ossification, extracellular matrix, and ECM-receptor interactions. Expression level results showed that Spp1, Sost, Ibsp, and Fn1 were significantly highly expressed in VC, and Col1a1 was incredibly low. RT-qPCR and IHC validation results were consistent with bioinformatic analysis. We found multiple pathways of hub genes acting in VC and identified 16 targeting drugs.

Conclusions

This study perfected the molecular regulatory mechanism of VC. Our results indicated that Spp1, Sost, Col1a1, Fn1, and Ibsp could be potential novel biomarkers for VC and promising therapeutic targets.

Downregulated Wnt2B Expression Suppresses Proliferation, Invasion, and Angiogenesis of Ovarian Cancer Cells Through Inhibiting the Wnt/β-Catenin Signaling Pathway

Ovarian cancer (OC) is known to be the most malignant gynecologic cancers. Wnt2B, a member of the Wnt family, plays a critical role in tumor development. However, the effect of Wnt2B on the occurrence and development of OC remains largely uncharacterized. In this study, immunohistochemistry assay indicated that Wnt2B was increased in our study cohort (OC). In addition, the expression of Wnt2B was positively correlated with TNM stages and metastasis of OC patients. Wnt2B markedly mediated the regulation of OC proliferation, invasion, and angiogenesis. Moreover, Wnt2B knockdown inactivated the Wnt/β-catenin signaling pathway. More importantly, the Wnt/β-catenin signaling pathway activator LiCl reversed the effect of Wnt2B knockdown on OC cell proliferation, angiogenesis, and invasion. Our data indicated that Wnt2B silencing could inhibit the proliferation, invasion, and angiogenesis of OC cells through downregulating the activity of Wnt/β-catenin pathway.

Lithium chloride inhibits the migration and invasion of osteosarcoma cells by blocking nuclear translocation of phospho-Erk

Lithium chloride (LiCl) is an important mood-stabilizing therapeutic agent for bipolar disorders, which has also been shown to inhibit cancer cell metastasis. Investigations of LiCl-induced signaling have focused mainly on extracellular signal regulated kinase 1/2 (ERK1/2) and glycogen synthase kinase 3 (GSK-3). However, little is known about the differences in cellular activities resulting from specific signaling via each of these pathways. In this study, we investigated the difference in responses between the Wnt/β-catenin and ERK pathways by LiCl or epidermal growth factor (EGF) treatment of osteosarcoma cells. In particular, we analyzed the mechanisms responsible for differences in cell mobility and cell proliferation when pERK or β-catenin is activated. In osteosarcoma cells treated with LiCl or EGF, active β-catenin and p-ERK protein levels were significantly increased compared to those in the control group. However, in wound healing and transwell invasion assays, U2OS and SaOS2 cell migration was significantly reduced by LiCl treatment but increased by EGF treatment. In addition, the proliferation of U2OS cells was reduced by LiCl treatment but increased by EGF treatment. Using immunofluorescence microscopy, we observed nuclear accumulation of phosphorylated ERK (pERK) with EGF treatment, but pERK was restricted to the perinuclear area with LiCl treatment. These results were confirmed using immunoblot assays after subcellular fractionation. Together, these data suggest that LiCl interferes with the translocation of pERK from the cytoplasm to the nucleus.