MiR-128-3p accelerates cardiovascular calcification and insulin resistance through ISL1-dependent Wnt pathway in type 2 diabetes mellitus rats

Vascular calcification is highly prevalent in patients with type 2 diabetes mellitus (T2DM), one of the most common chronic diseases with high morbidity and mortality. In recent years, microRNAs have been widely reported as potential biomarkers for the diagnosis and treatment of T2DM. We hypothesized that miR-128-3p is associated with cardiovascular calcification and insulin resistance (IR) in rats with T2DM by targeting ISL1 via the Wnt pathway. Microarray analysis was adopted to identify differentially expressed genes related to T2DM. T2DM models were induced in rats. Blood samples from normal and T2DM rats were used to detect islet β-cell function, islet sensitivity, and calcium content. Next, islet tissues were obtained to identify the expression of miR-128-3p, ISL1, and the Wnt signaling pathway- and apoptosis-related genes. Finally, apoptosis of islet β-cells was determined by flow cytometry. Through microarray analysis of GSE27382 and GSE23343, ISL1 was found to be downregulated in T2DM. In blood samples from T2DM rats, basic biochemical indicators, IR, and calcium content were increased, and islet sensitivity and islet β-cell function were decreased. Furthermore, upregulation of miR-128-3p and ISL1 gene silencing promoted the expression of Wnt-1, β-catenin, GSK-3β, and Bax and the phosphorylation of β-catenin and GSK-3β, inhibited c-fos, PDX-1, and Bcl-2 expression, and enhanced cell apoptosis. The key findings of our study demonstrate that miR-128-3p aggravates cardiovascular calcification and IR in T2DM rats by downregulating ISL1 through the activation of the Wnt pathway. Thus, miR-128-3p may serve as a potential target for the treatment of T2DM.     

Wnt lipidation: Roles in trafficking,modulation, and function

The Wnt signaling pathway consists of various downstream target proteins that have substantial roles in mammalian cell proliferation, differentiation, and development. Its aberrant activity can lead to uncontrolled proliferation and tumorigenesis. The posttranslational connection of fatty acyl chains to Wnt proteins provides the unique capacity for regulation of Wnt activity. In spite of the past belief that Wnt molecules are subject to dual acylation, it has been shown that these proteins have only one acylation site and undergo monounsaturated fatty acylation. The Wnt monounsaturated fatty acyl chain is more than just a hydrophobic coating and appears to be critical for Wnt signaling, transport, and receptor activation. Here, we provide an overview of recent findings in Wnt monounsaturated fatty acylation and the mechanism by which this lipid moiety regulates Wnt activity from the site of production to its receptor interactions.     

Wnt1-inducible signaling protein 1 regulates laryngeal squamous cell carcinoma glycolysis and chemoresistance via the YAP1/TEAD1/GLUT1 pathway

Wnt1-inducible signaling protein 1 (WISP1) is a matricellular protein and downstream target of Wnt/β-catenin signaling. This study sought to determine the role of WISP1 in glucose metabolism and chemoresistance in laryngeal squamous cell carcinoma. WISP1 expression was silenced or upregulated in Hep-2 cells by the transfection of WISP1 siRNA or AdWISP1 vector. Ectopic WISP1 expression regulated glucose uptake and lactate production in Hep-2 cells. Subsequently, the expression of glucose transporter 1 (GLUT1) was significantly modulated by WISP1. Furthermore, WISP1 increased cell survival rates, diminished cell death rates, and suppressed ataxia-telangiectasia-mutated (ATM)-mediated DNA damage response pathway in cancer cells treated with cisplatin through GLUT1. WISP1 also promoted cancer cell tumorigenicity and growth in mice implanted with Hep-2 cells. Additionally, WISP1 activated the YAP1/TEAD1 pathway that consequently contributed to the regulation of GLUT1 expression. In summary, WISP1 regulated glucose metabolism and cisplatin resistance in laryngeal cancer by regulating GLUT1 expression. WISP1 may be used as a potential therapeutic target for laryngeal cancer.     

Therapeutic potency of Wnt signaling antagonists in the pathogenesis of prostate cancer,current status and perspectives

Prostate cancer is a major cause of cancer-related death in males. Wnt/β-catenin signaling plays a critical role in the pathogenesis of this disease by regulating angiogenesis, drug resistance, cell proliferation, and apoptosis. Suppression of Wnt canonical or noncanonical signaling pathways via Wnt biological or pharmacological antagonists is a potentially novel therapeutic approach for patients with prostate cancer. This review summarizes the role of Wnt signaling inhibitors in the pathogenesis of prostate cancer for a better understanding and hence a better management of this disease.     

ULK1 negatively regulates Wnt signaling by phosphorylating Dishevelled

Wnt signaling pathway plays critical roles in body axes patterning, cell fate specification, cell proliferation, cell migration, stem cell maintenance, cancer development and etc. Deregulation of this pathway can be causative of cancer, metabolic disease and neurodegenerative disease such as Parkinson`s disease. Among the core components of Wnt signaling pathway, we discovered that Dishevelled (Dsh) interacts with ULK1 and is phosphorylated by ULK1. Unexpectedly, the knockdown of ULK1 elicited a marked increase in Wnt/β-catenin signaling. Multiple ULK1 phosphorylation sites existed on Dsh and many of them were located on the PDZ-DEP region. By using evolutionarily well conserved Drosophila Dsh, we found that S239, S247 and S254 in the PDZ-DEP region are involved in phosphorylation of Dsh by ULK1. Among these, S247 and S254 were conserved in human Dsh. When phospho-mimetic mutants (2D and 2E Dsh mutants) of these conserved residues were generated and expressed in the eyes of the fruit flies, the activity of Dsh was significantly decreased compared to wild type Dsh. Through additional alanine scanning, we further identified that S239, S247, S254, S266, S376, S554 and S555 on full length Dsh were phosphorylated by ULK1. In regards to the S266A mutation located in the PDZ domain among these phosphorylated residues, our results suggested that Dsh forms an SDS-resistant high molecular weight complex with β-catenin and TCF in the nucleus in an S266 phosphorylation-dependent manner. Based on these results, we propose that ULK1 plays a pivotal role in the regulation of Wnt/β-catenin signaling pathway by phosphorylating Dsh.     

Wnt‐induced activation of glucose metabolism mediates the in vivo neuroprotective roles of Wnt signaling in Alzheimer disease

Dysregulated Wnt signaling is linked to major neurodegenerative diseases, including Alzheimer disease (AD). In mouse models of AD, activation of the canonical Wnt signaling pathway improves learning/memory, but the mechanism for this remains unclear. The decline in brain function in AD patients correlates with reduced glucose utilization by neurons. Here, we test whether improvements in glucose metabolism mediate the neuroprotective effects of Wnt in AD mouse model. APPswe/PS1dE9 transgenic mice were used to model AD, Andrographolide or Lithium was used to activate Wnt signaling, and cytochalasin B was used to block glucose uptake. Cognitive function was assessed by novel object recognition and memory flexibility tests. Glucose uptake and the glycolytic rate were determined using radiotracer glucose. The activities of key enzymes of glycolysis such as hexokinase and phosphofructokinase, Adenosine triphosphate (ATP)/Adenosine diphosphate (ADP) levels and the pentose phosphate pathway and activity of glucose‐6 phosphate dehydrogenase were measured. Wnt activators significantly improved brain glucose utilization and cognitive performance in transgenic mice. Wnt signaling enhanced glucose metabolism by increasing the expression and/or activity of hexokinase, phosphofructokinase and AMP‐activated protein kinase. Inhibiting glucose uptake partially abolished the beneficial effects of Wnt signaling on learning/memory. Wnt activation also enhanced glucose metabolism in cortical and hippocampal neurons, as well as brain slices derived from APPswe/PS1E9 transgenic mice. Combined, these data provide evidence that the neuroprotective effects of Wnt signaling in AD mouse models result, at least in part, from Wnt‐mediated improvements in neuronal glucose metabolism.     

Long non-coding RNA ZFAS1 regulates the malignant progression of gastric cancer via the microRNA-200b-3p/Wnt1 axis

Gastric cancer is a common malignant tumor. Studies from our laboratory or others have shown that long non-coding RNA (lncRNA) zinc finger antisense (ZFAS)1 often acts as an oncogene. However, the molecular underpinnings of how ZFAS1 regulates gastric cancer remain to be elucidated. Results showed that ZFAS1 expression was upregulated, and microRNA-200b-3p (miR-200b) expression was downregulated in gastric cancer tissues. MiR-200b overexpression suppressed the proliferation, cell cycle process, and Wnt/β-catenin signaling of gastric cancer cells. Subsequently, we identified miR-200b is a target of ZFAS1 and Wnt1 is a target of miR-200b. Furthermore, promotion of cancer malignant progression and activation of Wnt/β-catenin signaling induced by ZFAS1 was counteracted by increasing miR-200b expression. In vivo, ZFAS1 knockdown suppressed the tumorigenesis with the upregulated miR-200b and the inactive Wnt/β-catenin signaling. Summarily, we demonstrated a critical role of miR-200b in gastric cancer, and ZFAS1 can promote malignant progression through regulating miR-200b mediated Wnt/β-catenin signaling.     

Retracted: The protective effects of TGR5 against ultraviolet B irradiation in epidermal stem cells

Repetitive exposure to ultraviolet radiation (UVR) results in continuous insults to the skin, including continuous loss of the capacities of epidermal stem cells (ESCs). Takeda G-protein-coupled receptor-5 (TGR5) participates in a variety of physiological activities, but its biological function in skin has not been reported. In this study, we report that TGR5 could be detected in ESCs and its expression was reduced after ultraviolet B (UV-B) irradiation. Treatment with the specific TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (GPBARA) prevented UV-B-induced oxidative stress by reducing 4-hydroxy-2-nonenal and increasing the level of glutathione. We also found that the presence of GPBARA improved UV-B irradiation-induced mitochondrial dysfunction by elevating mitochondrial membrane potential. Interestingly, our results indicate that GPBARA pretreatment suppressed UV-B irradiation-induced reduced cell viability, release of lactic dehydrogenase, and secretion of high mobility group box 1. Notably, GPBARA pretreatment inhibited UV-B irradiation-induced decrease in integrin β1 and Krt19, dependent on TGR5. Mechanistically, we found that the activation of TGR5 by GPBARA increased Wnt1, Wnt3a, Myc, and cyclin D1 in ESCs. Our data suggest a new function of TGR5 in regulating ESCs.     

Moderate activation of Wnt/β-catenin signaling promotes the survival of rat nucleus pulposus cells via regulating apoptosis,autophagy, and senescence

This study aimed to investigate the specific role of Wnt/β-catenin signaling in compression-induced apoptosis, autophagy, and senescence in rat nucleus pulposus (NP) cells. Initially, the cells underwent various periods of exposure to 1.0 MPa compression. Wnt/β-catenin signaling associated molecules were assessed in detail, and then 0, 24 and 48 hours exposure periods were selected. The cells were then divided into control, Wnt/β-catenin inhibitor (IWP-2), Wnt/β-catenin activator (LiCl), and β-catenin overexpression groups. After 0, 24, and 48 hours of compression, apoptosis, autophagy, and senescence were evaluated by Western blot analysis and real-time polymerase chain reaction and were visually observed by Hoechst33258, monodansylcadaverine, and SA-β-gal stainings, respectively. Additionally, the regulatory effect of Wnt/β-catenin signaling on cell morphology, viability, cell cycle, death ratio, and ultrastructure was detected to thoroughly evaluate the survival capacity of NP cells. The results established that compression elicited a time-dependent activation of Wnt/β-catenin signaling. The IWP-2 treatment decreased cell survival rate, which corresponded to downregulation of autophagy as well as increases in apoptosis and senescence. LiCl treatment enabled more efficient of cell survival accompanied by increased autophagy and downregulated apoptosis and senescence; however, in contrast to LiCl, overexpression of β-catenin aggravated compression-induced NP cells death. In conclusion, moderate activation of Wnt/β-catenin signaling enables more efficient of NP cells survival via downregulation of apoptosis, senescence, and upregulation of autophagy, and overactivation of Wnt/β-catenin signaling achieved the opposite effect. Treatment strategies that aim to regulate Wnt/β-catenin signaling might be a novel target for improving compression-induced NP cells death and potential treatment of intervertebral disc degeneration.