Wnt5a/Ror2 pathway contributes to the regulation of cholesterol homeostasis and inflammatory response in atherosclerosis

Endothelial Cells Mediated by STING Regulate Oligodendrogenesis and Myelination During Brain Development

Oligodendrocyte precursor cells (OPCs) migrate extensively using blood vessels as physical scaffolds in the developing central nervous system. Although the association of OPCs with the vasculature is critical for migration, the regulatory mechanisms important for OPCs proliferative and oligodendrocyte development are unknown. Here, a correlation is demonstrated between the developing vasculature and OPCs response during brain development. Deletion of endothelial stimulator of interferon genes (STING) disrupts angiogenesis by inhibiting farnesyl-diphosphate farnesyltransferase 1 (FDFT1) and thereby reducing cholesterol synthesis. Furthermore, the perturbation of metabolic homeostasis in endothelial cells increases interleukin 17D production which mediates the signal transduction from endothelial cells to OPCs, which inhibits oligodendrocyte development and myelination and causes behavioral abnormalities in adult mice. Overall, these findings indicate how the endothelial STING maintains metabolic homeostasis and contributes to oligodendrocyte precursor cells response in the developing neocortex.

Tetrandrine ameliorated atherosclerosis in vitamin D3/high cholesterol diet-challenged rats via modulation of miR-34a and Wnt5a/Ror2/ABCA1/NF-kB trajectory

Atherosclerosis (AS) is a major cause of cardiovascular diseases that may lead to mortality. This study aimed to evaluate the therapeutic potential of tetrandrine in high cholesterol diet (HCD)-induced atherosclerosis, in rats, via modulation of miR-34a, as well as, Wnt5a/Ror2/ABCA1/NF-κB pathway and to compare its efficacy with atorvastatin. Induction of AS, in male rats, was done via IP administration of vitamin D3 (70 U/Kg for 3 days) together with HCD. At the end of the 9th week, rats were treated with atorvastatin at a dose of 20 mg/kg, and tetrandrine at different doses of (18.75, and 31.25 mg/kg) for 22 days. Serum inflammatory cytokines and lipid profile, liver oxidative stress parameters, and aortic tissue Wnt5a, Ror2, ABCA1, NF-κB, miR-34a levels were assessed in all experimental groups. Histopathological and Immunohistochemical assessments of aortic tissue sections were done. Results showed that tetrandrine treatment reverted the inflammatory and oxidative stress state together with reducing the serum lipids via modulating miR-34a, and Wnt5a/Ror2/ABCA1/NF-κB pathway. Moreover, it reverted the histopathological abnormalities observed in AS rats. Tetrandrine beneficial effects, in both doses, were comparable to that of atorvastatin, in most of the discussed parameters. These findings praise tetrandrine as a promising agent for management of atherosclerosis.

Research Progress on the Mechanism of the SFRP-Mediated Wnt Signalling Pathway Involved in Bone Metabolism in Osteoporosis

Osteoporosis (OP) is a metabolic bone disease linked to an elevated fracture risk, primarily stemming from disruptions in bone metabolism. Present clinical treatments for OP merely alleviate symptoms. Hence, there exists a pressing need to identify novel targets for the clinical treatment of OP. Research indicates that the Wnt signalling pathway is modulated by serum-secreted frizzled-related protein 5 (SFRP5), potentially serving as a pivotal regulator in bone metabolism disorders. Moreover, studies confirm elevated SFRP5 expression in OP, with SFRP5 overexpression leading to the downregulation of Wnt and β-catenin proteins in the Wnt signalling pathway, as well as the expression of osteogenesis-related marker molecules such as RUNX2, ALP, and OPN. Conversely, the opposite has been reported when SFRP5 is knocked out, suggesting that SFRP5 may be a key factor involved in the regulation of bone metabolism via the Wnt signalling axis. However, the molecular mechanisms underlying the action of SFRP5-induced OP have yet to be comprehensively elucidated. This review focusses on the molecular structure and function of SFRP5 and the potential molecular mechanisms of the SFRP5-mediated Wnt signalling pathway involved in bone metabolism in OP, providing reasonable evidence for the targeted therapy of SFRP5 for the prevention and treatment of OP.

Wnt5a: A promising therapeutic target for inflammation, especially rheumatoid arthritis

BACKGROUND

Wnt5a is a member of the Wnt protein family, which acts on classical or multiple non-classical Wnt signaling pathways by binding to different receptors. The expression regulation and signal transduction of Wnt5a is closely related to the inflammatory response. Abnormal activation of Wnt5a signaling is an important part of inflammation and rheumatoid arthritis (RA).

OBJECTIVES

This paper mainly focuses on Wnt5a protein and its mediated signaling pathway, summarizes the latest research progress of Wnt5a in the pathological process of inflammation and RA, and looks forward to the main directions of Wnt5a in RA research, aiming to provide a theoretical basis for the prevention and treatment of RA diseases by targeting Wnt5a.

RESULTS

Wnt5a is highly expressed in activated blood vessels, histocytes and synoviocytes in inflammatory diseases such as sepsis, sepsis, atherosclerosis and rheumatoid arthritis. It mediates the production of pro-inflammatory cytokines and chemokines, regulates the migration and recruitment of various immune effector cells, and thus participates in the inflammatory response. Wnt5a plays a pathological role in synovial inflammation and bone destruction of RA, and may be an important clinical therapeutic target for RA.

CONCLUSION

Wnt5a is involved in the pathological process of inflammation and interacts with inflammatory factors. Wnt5a may be a new target for regulating the progression of RA disease and intervening therapy because of its multi-modal effects on the etiology of RA, especially as a regulator of osteoclast activity and inflammation.

Zinc Improves Semen Parameters in High-Fat Diet-Induced Male Rats by Regulating the Expression of LncRNA in Testis Tissue

This study aimed to identify differentially expressed LncRNAs in testis tissue of male rats induced by high-fat diet and their changes after zinc supplementation, by constructing a high-fat feeding rat model, and then supplemented with zinc, and observed the expression of LncRNA in three groups of normal, high-fat fed, and zinc-intervened rats. Experimental studies show that the semen parameters of male rats with high-fat diet were decreased but recovered after zinc supplementation, and the related LncRNA also changed. Zinc may improve the high-fat diet-induced reduction of semen parameters by changing the expression of related LncRNA.

Mechanisms of the Wnt Pathways as a Potential Target Pathway in Atherosclerosis

The proteins of the Wnt family are involved in a variety of physiological processes by means of several canonical and noncanonical signaling pathways. Wnt signaling has been recently identified as a major player in atherogenesis. In this review, we summarize the existing knowledge on the influence of various components of the Wnt signaling pathways on the initiation and progression of atherosclerosis and associated conditions. We used the PubMed database to search for recent papers on the involvement of the Wnt pathways in atherosclerosis. We used the combination of "Wnt" and "atherosclerosis" keywords to find the initial papers, and chose papers published after 2018. In the first section of the paper, we describe the general mechanisms of the Wnt signaling pathways and their components. The next section is dedicated to existing studies assessing the implication of Wnt signaling elements in different atherogenic processes, such as cholesterol retention, endothelial dysfunction, vascular inflammation, and atherosclerotic calcification of the vessels. Lastly, various therapeutic strategies based on interference with the Wnt signaling pathways are considered. We also compare the efficacy and availability of the proposed treatment methods. Wnt signaling can be considered a potential target in the treatment and prevention of atherosclerosis. Therefore, in this review, we reviewed evidences showing that wnt signaling is an important signal for developing appropriate treatment strategies for atherosclerosis.

Epigenetic regulation in opioid induced hyperalgesia

About 25 million American adults experience pain daily and one of the most commonly prescribed drugs to treat pain are opioids. Prolonged opioid usage and dose escalations can cause a paradoxical response where patients experience enhanced pain sensitivity. This opioid induced hyperalgesia (OIH) is a major hurdle when treating pain in the clinic because its underlying mechanisms are still not fully understood. OIH is also commonly overlooked and lacks guidelines to prevent its onset. Research on pain disorders and opioid usage have recognized potential epigenetic drivers of disease including DNA methylation, histone modifications, miRNA regulation, but their involvement in OIH has not been well studied. This article discusses epigenetic changes that may contribute to pathogenesis, with an emphasis on miRNA alterations in OIH. There is a crucial gap in knowledge including how multiple epigenetic modulators contribute to OIH. Elucidating the epigenetic changes underlying OIH and the crosstalk among these mechanisms could lead to the development of novel targets for the prevention and treatment of this painful phenomena.

Downregulation of ROR2 attenuates LPS-induced A549 cell injury through JNK and ERK signaling pathways

BACKGROUND

We aimed to determine whether receptor tyrosine kinase-like orphan receptor 2 (ROR2) is involved in the occurrence of acute lung injury (ALI) by an animal study and explore the effect of ROR2 downregulation on lipopolysaccharide (LPS)-treated human lung carcinoma A549 cells by a cytological study.

METHODS

Murine models of ALI were successfully constructed by intratracheal instillation of LPS. Meanwhile, A549 cell line stimulated with LPS was used for a cytological study. The expression of ROR2 and its effect on proliferation, cell cycle, apoptosis, and inflammation were detected.

RESULTS

It was found that LPS administration markedly inhibited the cell proliferation, resulted in cell cycle arrest at G1 phage, elevated levels of pro-inflammatory cytokines and apoptosis rate of A549 cells. However, LPS-mediated adverse effects mentioned above were significantly ameliorated by downregulation of ROR2 in comparison with LPS treatment. In addition, administration of ROR2 siRNA notably decreased the phosphorylation level of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in LPS-challenged A549 cells.

CONCLUSIONS

Thus, the present data indicate that downregulation of ROR2 may decrease LPS-induced inflammatory responses and cell apoptosis through inhibiting JNK and ERK signaling pathway, which attenuates ALI.

Transcriptomic profiles of the ruminal wall in Italian Mediterranean dairy buffaloes fed green forage

BACKGROUND

Green feed diet in ruminants exerts a beneficial effect on rumen metabolism and enhances the content of milk nutraceutical quality. At present, a comprehensive analysis focused on the identification of genes, and therefore, biological processes modulated by the green feed in buffalo rumen has never been reported. We performed RNA-sequencing in the rumen of buffaloes fed a total mixed ration (TMR) + the inclusion of 30% of ryegrass green feed (treated) or TMR (control), and identified differentially expressed genes (DEGs) using EdgeR and NOISeq tools.

RESULTS

We found 155 DEGs using EdgeR (p-values < 0.05) and 61 DEGs using NOISeq (prob ≥0.8), 30 of which are shared. The rt-qPCR validation suggested a higher reliability of EdgeR results as compared with NOISeq data, in our biological context. Gene Ontology analysis of DEGs identified using EdgeR revealed that green feed modulates biological processes relevant for the rumen physiology and, then, health and well-being of buffaloes, such as lipid metabolism, response to the oxidative stress, immune response, and muscle structure and function. Accordingly, we found: (i) up-regulation of HSD17B13, LOC102410803 (or PSAT1) and HYKK, and down-regulation of CDO1, SELENBP1 and PEMT, encoding factors involved in energy, lipid and amino acid metabolism; (ii) enhanced expression of SIM2 and TRIM14, whose products are implicated in the immune response and defense against infections, and reduced expression of LOC112585166 (or SAAL1), ROR2, SMOC2, and S100A11, encoding pro-inflammatory factors; (iii) up-regulation of NUDT18, DNAJA4 and HSF4, whose products counteract stressful conditions, and down-regulation of LOC102396388 (or UGT1A9) and LOC102413340 (or MRP4/ABCC4), encoding detoxifying factors; (iv) increased expression of KCNK10, CACNG4, and ATP2B4, encoding proteins modulating Ca²⁺ homeostasis, and reduced expression of the cytoskeleton-related MYH11 and DES.

CONCLUSION

Although statistically unpowered, this study suggests that green feed modulates the expression of genes involved in biological processes relevant for rumen functionality and physiology, and thus, for welfare and quality production in Italian Mediterranean dairy buffaloes. These findings, that need to be further confirmed through the validation of additional DEGs, allow to speculate a role of green feed in the production of nutraceutical molecules, whose levels might be enhanced also in milk.

The cell origins of foam cell and lipid metabolism regulated by mechanical stress in atherosclerosis

Atherosclerosis is an inflammatory disease initiated by endothelial activation, in which lipoprotein, cholesterol, extracellular matrix, and various types of immune and non-immune cells are accumulated and formed into plaques on the arterial wall suffering from disturbed flow, characterized by low and oscillating shear stress. Foam cells are a major cellular component in atherosclerotic plaques, which play an indispensable role in the occurrence, development and rupture of atherosclerotic plaques. It was previously believed that foam cells were derived from macrophages or smooth muscle cells, but recent studies have suggested that there are other sources of foam cells. Many studies have found that the distribution of atherosclerotic plaques is not random but distributed at the bend and bifurcation of the arterial tree. The development and rupture of atherosclerotic plaque are affected by mechanical stress. In this review, we reviewed the advances in foam cell formation in atherosclerosis and the regulation of atherosclerotic plaque and lipid metabolism by mechanical forces. These findings provide new clues for investigating the mechanisms of atherosclerotic plaque formation and progression.

Non-canonical WNT signalling in cardiovascular disease: mechanisms and therapeutic implications

WNT signalling comprises a diverse spectrum of receptor-mediated pathways activated by a large family of WNT ligands and influencing fundamental biological processes. WNT signalling includes the β-catenin canonical pathway and the non-canonical pathways, namely the planar cell polarity and the calcium-dependent pathways. Advances over the past decade have linked non-canonical WNT signalling with key mechanisms of atherosclerosis, including oxidative stress, endothelial dysfunction, macrophage activation and vascular smooth muscle cell phenotype regulation. In addition, non-canonical WNT signalling is involved in crucial aspects of myocardial biology, from fibrosis to hypertrophy and oxidative stress. Importantly, non-canonical WNT signalling activation has complex effects in adipose tissue in the context of obesity, thereby potentially linking metabolic and vascular diseases. Tissue-specific targeting of non-canonical WNT signalling might be associated with substantial risks of off-target tumorigenesis, challenging its therapeutic potential. However, novel technologies, such as monoclonal antibodies, recombinant decoy receptors, tissue-specific gene silencing with small interfering RNAs and gene editing with CRISPR-Cas9, might enable more efficient therapeutic targeting of WNT signalling in the cardiovascular system. In this Review, we summarize the components of non-canonical WNT signalling, their links with the main mechanisms of atherosclerosis, heart failure and arrhythmias, and the rationale for targeting individual components of non-canonical WNT signalling for the treatment of cardiovascular disease.

The Ror-Family Receptors in Development, Tissue Regeneration and Age-Related Disease

The Ror-family proteins, Ror1 and Ror2, act as receptors or co-receptors for Wnt5a and its related Wnt proteins to activate non-canonical Wnt signaling. Ror1 and/or Ror2-mediated signaling plays essential roles in regulating cell polarity, migration, proliferation and differentiation during developmental morphogenesis, tissue-/organo-genesis and regeneration of adult tissues following injury. Ror1 and Ror2 are expressed abundantly in developing tissues in an overlapping, yet distinct manner, and their expression in adult tissues is restricted to specific cell types such as tissue stem/progenitor cells. Expression levels of Ror1 and/or Ror2 in the adult tissues are increased following injury, thereby promoting regeneration or repair of these injured tissues. On the other hand, disruption of Wnt5a-Ror2 signaling is implicated in senescence of tissue stem/progenitor cells that is related to the impaired regeneration capacity of aged tissues. In fact, Ror1 and Ror2 are implicated in age-related diseases, including tissue fibrosis, atherosclerosis (or arteriosclerosis), neurodegenerative diseases, and cancers. In these diseases, enhanced and/or sustained (chronic) expression of Ror1 and/or Ror2 is observed, and they might contribute to the progression of these diseases through Wnt5a-dependent and -independent manners. In this article, we overview recent advances in our understanding of the roles of Ror1 and Ror2-mediated signaling in the development, tissue regeneration and age-related diseases, and discuss their potential to be therapeutic targets for chronic inflammatory diseases and cancers.

DOCK9 antisense RNA2 interacts with LIN28B to stabilize Wnt5a and boosts proliferation and migration of oxidized low densitylipoprotein-induced vascular smooth muscle cells

Study has suggested that long non-coding RNA DOCK9 antisense RNA2 (LncRNA DOCK9-AS2) may play an important role in atherosclerosis, but the specific role is unclear. In this article, we aim to explore the role and mechanism of DOCK9-AS2 in the proliferation and migration of vascular smooth muscle cells (VSMCs) in atherosclerosis. VSMCs were treated with oxidized low densitylipoprotein (ox-LDL) for 24 h to establish the model of atherosclerosis in vitro. Gain- and loss-of function experiments were conducted. Cell Counting Kit-8 (CCK-8) assay and Ki67 staining were used to evaluate the ability cell proliferation. Transwell assay and immunofluorescence staining of N-Cadherin and E-cadherin were carried out to detect cell migration. RNA immunoprecipitation (RIP) experiment, pull down assay and mRNA stability analysis were used to assess the relationship of DOCK9-AS2, Wnt5a and LIN28B. Western blot analysis was used to measure the protein expression levels. The results showed that DOCK9-AS2 knockdown inhibited the proliferation and migration of ox-LDL-induced VSMCs. Further study on the interaction between DOCK9-AS2, Wnt5a and LIN28B revealed that LIN28B could both directly interact with DOCK9-AS2 and Wnt5a, and DOCK9-AS2 regulated Wnt5a by targeting LIN28B. In addition, Overexpression of Wnt5a partly abolished the inhibitory effects of LIN28B knockdown or DOCK9-AS2 knockdown on cell proliferation and migration induced by in ox-LDL-induced proliferation and migration. In conclusion, the results showed that DOCK9-AS2 promoted the proliferation and migration of vascular smooth muscle cells in atherosclerosis through regulating Wnt5a by targeting LIN28B.

The Levels of Wnt5a and Its Receptors Frizzled5 and Frizzled2 as Immunohistochemical Biomarkers of Severity of Psoriasis

Purpose

Psoriasis is a systemic, chronic and inflammatory condition. The exact pathogenesis is unclear. The abnormal expression of Wnt5a pathway in psoriasis vulgaris has been confirmed. Whether it is related to the severity of psoriasis is unclear.

Methods

Thirty-eight skin lesions from psoriasis vulgaris patients and 22 healthy adult skin tissues were taken. The semi-quantitative immunohistochemistry score of Wnt5a, Frizzled5 and Frizzled2 was evaluated under a microscope by two independent dermatologists. Psoriasis area and severity index (PASI) score system was used to evaluate the disease severity.

Results

The average PASI score of the patients was 16.25 ± 7.8, and the average duration of disease was 19.6 ± 10.4 months. Wnt5a, Frizzled5 and Frizzled2 were highly expressed in psoriasis lesions. The semi-quantitative immunohistochemistry scores of Wnt5a, Frizzled5 and Frizzled2 were positively correlated with PASI scores (r = 0.71, r = 0.46, r = 0.65, respectively, all P-value < 0.01), but not correlated with duration of disease (r = 0.11, r = 0.17, r = 0.29, respectively, all P-value > 0.05). There were significant positive correlations between Wnt5a and Frizzled5 (r = 0.57, P-value < 0.01), as well as Wnt5a and Frizzled2 (r = 0.59, P-value < 0.01).

Conclusion

Wnt5a and its receptors play an important role in pathogenesis of psoriasis vulgaris and are positively correlated with the severity of psoriasis, and may be one of the immunohistochemical predictors of the severity of the disease.

Celastrol induces lipophagy via the LXRα/ABCA1 pathway in clear cell renal cell carcinoma

Celastrol is a triterpene derived from the traditional Chinese medicine Tripterygium wilfordii Hook f, which displays potential anticancer activity. In the present study, we investigated the anticancer effects of celastrol against clear cell renal cell carcinoma (ccRCC) and the underlying mechanisms. Using Cancer Genome Atlas (TCGA) database and genotype-tissue expression (GTEx) database we conducted a bioinformatics analysis, which showed that the mRNA levels of liver-X receptors α (LXRα) and ATP-binding cassette transporter A1 (ABCA1) in ccRCC tissues were significantly lower than those in adjacent normal tissues. This result was confirmed by immunoblotting analysis of 4 ccRCC clinical specimens, which showed that the protein expression of LXRα and ABCA1 was downregulated. Similar results were obtained in a panel of ccRCC cell lines (786-O, A498, SN12C, and OS-RC-2). In 786-O and SN12C cells, treatment with celastrol (0.25-2.0 μM) concentration-dependently inhibited the cell proliferation, migration, and invasion as well as the epithelial-mesenchymal transition (EMT) process. Furthermore, we demonstrated that celastrol inhibited the invasion of 786-O cells through reducing lipid accumulation; celastrol concentration-dependently promoted autophagy to reduce lipid storage. Moreover, we revealed that celastrol dramatically activated LXRα signaling, and degraded lipid droplets by inducing lipophagy in 786-O cells. Finally, celastrol promoted cholesterol efflux from 786-O cells via ABCA1. In high-fat diet-promoted ccRCC cell line 786-O xenograft model, administration of celastrol (0.25, 0.5, 1.0 mg·kg-1·d-1, for 4 weeks, i.p.) dose-dependently inhibited the tumor growth with upregulated LXRα and ABCA1 protein in tumor tissue. In conclusion, this study reveals that celastrol triggers lipophagy in ccRCC by activating LXRα, promotes ABCA1-mediated cholesterol efflux, suppresses EMT progress, and ultimately inhibits cell proliferation, migration, and invasion as well as tumor growth. Thus, our study provides evidence that celastrol can be used as a lipid metabolism-based anticancer therapeutic approach.

Celastrol ameliorates vascular neointimal hyperplasia through Wnt5a-involved autophagy

Neointimal hyperplasia caused by the excessive proliferation of vascular smooth muscle cells (VSMCs) is the pathological basis of restenosis. However, there are few effective strategies to prevent restenosis. Celastrol, a pentacyclic triterpene, has been recently documented to be beneficial to certain cardiovascular diseases. Based on its significant effect on autophagy, we proposed that celastrol could attenuate restenosis through enhancing autophagy of VSMCs. In the present study, we found that celastrol effectively inhibited the intimal hyperplasia and hyperproliferation of VSMCs by inducing autophagy. It was revealed that autophagy promoted by celastrol could induce the lysosomal degradation of c-MYC, which might be a possible mechanism contributing to the reduction of VSMCs proliferation. The Wnt5a/PKC/mTOR signaling pathway was found to be an underlying mechanism for celastrol to induce autophagy and inhibit the VSMCs proliferation. These observations indicate that celastrol may be a novel drug with a great potential to prevent restenosis.

Gut Microbiota Combined With Metabolomics Reveals the Repeated Dose Oral Toxicity of β-Cyclodextrin in Mice

Βeta-cyclodextrin (β-CD) with a hydrophobic cavity enables the formation of inclusion complexes with organic molecules. The formation of host–guest complexes makes the application of β-CD popular in many fields, but their interaction with organisms is poorly understood. In the present study, the effect of β-CD on gut microbiota (16S rRNA gene sequencing), serum metabolites (gas chromatography–mass spectrometry platform), and their correlation (Pearson correlation analysis) was investigated after 14 days repeated oral exposure in mice. β-CD did not significantly affect the α-diversity indexes, including Richness, Chao1, Shannon and Simpson indexes, but disturbed the structure of the gut bacteria according to the result of principal component analysis (PCA). After taxonomic assignment, 1 in 27 phyla, 2 in 48 classes, 3 in 107 orders, 6 in 192 families, and 8 in 332 genera were significantly different between control and β-CD treated groups. The serum metabolites were significantly changed after β-CD treatment according to the result of unsupervized PCA and supervised partial least squares-discriminant analysis (PLS-DA). A total of 112 differential metabolites (89 downregulated and 23 upregulated) were identified based on the VIP >1 from orthogonal PLS-DA and p <0.05 from Student’s t-test. The metabolic pathways, including ABC transporters, pyrimidine metabolism, purine metabolism, glucagon signaling pathway, insulin signaling pathway, and glycolysis/gluconeogenesis, were enriched by KEGG pathway analysis. Our study provides a general observation of gut microbiota, serum metabolites and their correlation after exposure to β-CD in mice, which will be helpful for future research and application of β-CD.

Apolipoprotein C1 stimulates the malignant process of renal cell carcinoma via the Wnt3a signaling

Background

Renal cell carcinoma (RCC) is a clinically common tumor in the urinary system, showing an upward trend of both incidence and mortality. Apolipoprotein C1 (APOC1) has been identified as a vital regulator in tumor progression. This study aims to uncover the biological function of APOC1 in RCC process and the underlying mechanism.

Methods

Differential levels of APOC1 in RCC samples and normal tissues in a downloaded TCGA profile and clinical samples collected in our center were detected by quantitative reverse transcription PCR (qRT-PCR). The prognostic value of APOC1 in RCC was assessed by depicting Kaplan–Meier survival curves. After intervening APOC1 level by transfection of sh-APOC1 or oe-APOC1, changes in phenotypes of RCC cells were examined through CCK-8, colony formation, Transwell assay and flow cytometry. Subsequently, protein levels of EMT-related genes influenced by APOC1 were determined by Western blot. The involvement of the Wnt3a signaling in APOC1-regulated malignant process of RCC was then examined through a series of rescue experiments. Finally, a RCC xenograft model was generated in nude mice, aiming to further clarify the in vivo function of APOC1 in RCC process.

Results

APOC1 was upregulated in RCC samples. Notably, its level was correlated to overall survival of RCC patients, displaying a certain prognostic value. APOC1 was able to stimulate proliferative, migratory and invasive abilities in RCC cells. The Wnt3a signaling was identified to be involved in APOC1-mediated RCC process. Notably, Wnt3a was able to reverse the regulatory effects of APOC1 on RCC cell phenotypes. In vivo knockdown of APOC1 in xenografted nude mice slowed down the growth of RCC.

Conclusions

APOC1 stimulates the malignant process of RCC via targeting the Wnt3a signaling.

A Screen for PKN3 Substrates Reveals an Activating Phosphorylation of ARHGAP18

Protein kinase N3 (PKN3) is a serine/threonine kinase implicated in tumor progression of multiple cancer types, however, its substrates and effector proteins still remain largely understudied. In the present work we aimed to identify novel PKN3 substrates in a phosphoproteomic screen using analog sensitive PKN3. Among the identified putative substrates we selected ARHGAP18, a protein from RhoGAP family, for validation of the screen and further study. We confirmed that PKN3 can phosphorylate ARHGAP18 in vitro and we also characterized the interaction of the two proteins, which is mediated via the N-terminal part of ARHGAP18. We present strong evidence that PKN3-ARHGAP18 interaction is increased upon ARHGAP18 phosphorylation and that the phosphorylation of ARHGAP18 by PKN3 enhances its GAP domain activity and contributes to negative regulation of active RhoA. Taken together, we identified new set of potential PKN3 substrates and revealed a new negative feedback regulatory mechanism of Rho signaling mediated by PKN3-induced ARHGAP18 activation.