Association between SPRY1 and TET3 in skin photoaging and natural aging mechanisms

BACKGROUND

SPRY1 is associated with the invasiveness and prognosis of various tumors, and TET3 affects aging by regulating gene expression.

AIMS

We investigated the roles of SPRY1 and TET3 in natural skin aging, replicative aging, and photoaging, along with the effect of UVA on genome-wide DNA methylation in HaCaT cells.

METHODS

TET3 and SPRY1 expression were measured in the skin of patients of different age groups, as well as in vitro human skin, HaCaT cell replicative senescence, and HaCaT and HaCaT-siTET3 cell photoaging models. Senescence was verified using β-galactosidase staining, and DNA damage was detected using immunofluorescence staining for γ-H2A.X. 5-Methyl cytosine (5-mC) content in the genome was determined using ELISA.

RESULTS

SPRY1 expression increased with age, whereas TET3 expression decreased. Similarly, SPRY1 was upregulated and TET3 was downregulated with increasing cell passages. TET3-siRNA upregulated SPRY1 expression in HaCaT cells. UVA irradiation promoted HaCaT cell senescence and induced cellular DNA damage. SPRY1 was upregulated and TET3 was downregulated upon UVA irradiation. Genome-wide 5-mC content increased upon TET3 silencing and UVA irradiation, indicating a surge in overall methylation.

CONCLUSIONS

SPRY1 and TET3 are natural skin aging-related genes that counteract to regulate replicative aging and UVA-induced photoaging in HaCaT cells. The cell photoaging model may limit experimental bias caused by different exposure times of skin model samples.

Lung cancer-derived exosomal miR-132-3p contributed to interstitial lung disease development

PURPOSE

Interstitial lung diseases (ILDs) have high morbidity and mortality and poor prognosis. The significance of microRNAs (miRNAs) was highlighted in ILDs development. Currently, we attempted to confirm the functions of lung cancer-derived exosomal miR-132-3p and reveal the underlying mechanism.

METHOD

Characteristics of exosomes were verified by transmission electron microscope (TEM), nanoparticle tracking analysis, and Western blot assay. Exosome uptake for the normal human lung fibroblasts (NHLF) was assessed using a PKH67 staining assay. MTT and colony formation assays were applied to examine the proliferation abilities of NHLF. The interaction between miR-132-3p and sprouty1 (SPRY1) was confirmed by a luciferase reporter assay.

RESULTS

Lung cancer-derived exosomes promoted normal human lung fibroblast activation. Exosome inhibitor GW4869 reversed the effects of Exo on NHLF. Subsequently, miR-132-3p in lung cancer-derived exosomes activated the normal human lung fibroblast and promoted interstitial lung disease development ex vivo. Next, SPRY1 was verified to be the binding protein of miR-132-3p, and sh-SPRY1 abrogated the effects of the miR-132-3p inhibitor on NHLF.

CONCLUSION

Exosomal miR-132-3p from A549 cells accelerated the development of interstitial lung disease through binding to SPRY1, which might serve as an important target for ILDs.

Overexpression of NR4A2 alleviates renal and myocardial injury in diabetes nephropathy rats through the HDAC11/SPRY1 pathway

BACKGROUND

Diabetic nephropathy (DN) remains the most prevalent cause of end-stage renal disease. Nuclear receptor subfamily 4 group A member 2 (NR4A2) is a nuclear receptor with unique physiological characteristics.

OBJECTIVE

This study explored the molecular mechanism of NR4A2 in renal and cardiac functions of DN rats.

METHODS

A rat model of DN was established by intraperitoneal injection of streptozocin. NR4A2, histone deacetylase 11 (HDAC11), and sprouty 1 (SPRY1) expressions were detected. The fasting blood glucose (FBG), urinary albumin (UAlb), serum creatinine (Cr), and blood urea nitrogen (BUN) were determined. The pathological injury of renal and myocardial tissues was evaluated. The mitral early to late diastolic flow velocity ratio (E/A ratio), left ventricular ejection fraction (LVEF), left ventricular systolic function (LVSF), left ventricular internal dimension systole (LVIDs), and left ventricular internal diameter diastole (LVIDd) were tested, and the levels of serum cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) were examined. The enrichment of NR4A2 in HDAC11 promoter and enrichment of H3K27 acetylation in SPRY1 promoter were measured.

RESULTS

NR4A2 and SPRY1 were downregulated while HDAC11 was upregulated in renal and myocardial tissues of DN rats. NR4A2 overexpression reduced FBG, UAlb, Cr, and BUN, alleviated pathological injury of renal and myocardial tissues, elevated the E/A ratio, LVEF, and LVFS, but reduced LVIDs, and decreased serum cTnI and CK-MB. NR4A2 depressed HDAC11 expression by binding to the HDAC11 promoter. HDAC11 repressed SPRY1 transcription by suppressing the H3K27ac level. HDAC11 overexpression or SPRY1 inhibition reversed the alleviating effect of NR4A2 overexpression on DN rats.

CONCLUSION

NR4A2 was poorly expressed in DN rats. NR4A2 overexpression suppressed HDAC11 expression by binding to the HDAC11 promoter and enhanced SPRY1 transcription by enhancing H3K27 acetylation, thereby alleviating the renal and myocardial injury of DN rats.

Circ_0099630 Participates in SPRY1-Mediated Repression in Periodontitis

BACKGROUND

Periodontitis is chronic inflammation that causes damage to periodontal tissues and cementum. It has been reported that circular RNA hsa_circ_0099630 (circ_0099630) was overexpressed in gingival samples from patients with periodontitis. However, the function of circ_0099630 on the osteogenic differentiation of periodontal ligament cells (PDLCs) in periodontitis remains unclear.

METHODS

Periodontal ligaments from patients with periodontitis and third molars (termed wisdom teeth) were utilised to isolate inflamed PDLCs (iPDLCs) and healthy PDLCs (hPDLCs). Expression levels of circ_0099630 in isolated PDLCs were assessed using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Effects of circ_0099630 overexpression and silencing on iPDLC viability, proliferation, and cycle progression were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays. The osteogenic differentiation was detected by analysing the alkaline phosphatase (ALP) activity, mineralisation amount, and osteogenic markers osterix (OSX), ALP, and RUNX2 in iPDLCs. The regulatory mechanism of circ_0099630 was predicted by bioinformatics analysis and validated by dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays.

RESULTS

Circ_0099630 was underexpressed in iPDLCs compared to hPDLCs. Overexpression of circ_0099630 repressed iPDLC proliferation and osteogenic differentiation, but circ_0099630 silencing exerted an opposing effect. Mechanically, circ_0099630 sponged miR-212-5p to block the inhibiting effect of miR-212-5p on SPRY1. Elevated expression of SPRY1 partly reversed the promoting effect of circ_0099630 knockdown on iPDLC proliferation and osteogenic differentiation.

CONCLUSIONS

Circ_0099630 curbed PDLC proliferation and osteogenic differentiation through elevating SPRY1 expression via sponging miR-212-5p in periodontitis.

Circ_0110251 overexpression alleviates IL-1β-induced chondrocyte apoptosis and extracellular matrix degradation by regulating miR-3189-3p/SPRY1 axis in osteoarthritis

BACKGROUND

Mounting evidence indicates that circular RNAs (circRNAs) are involved in the progression of human diseases, including osteoarthritis (OA). In this study, we focussed on the functions and potential mechanism of circ_0110251 in OA.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circ_0110251, collagen type XI alpha 1 chain (COL11A1), microRNA-3189-3p (miR-3189-3p) and sprouty receptor tyrosine kinase signalling antagonist 1 (SPRY1). The cyclisation analysis of circ_0110251 was analysed by RNase R and Actinomycin D assays. Flow cytometry analysis was conducted to analyse cell apoptosis. Western blot assay was used to measure the levels of extracellular matrix degradation (ECM)-associated markers and SPRY1. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay were performed to analyse the relationships among circ_0110251, miR-3189-3p and SPRY1.

RESULTS

Circ_0110251 was downregulated in OA cartilage tissues and IL-1β-induced chondrocytes. IL-1β promoted the apoptosis and ECM degradation in chondrocytes, while circ_0110251 overexpression relieved the effects. Circ_0110251 functioned as the sponge for miR-3189-3p and miR-3189-3p overexpression reversed the effect of circ_0110251 on IL-1β-induced chondrocyte damage. Additionally, SPRY1 served as the target gene of miR-3189-3p. MiR-3189-3p inhibition ameliorated IL-1β-induced chondrocyte apoptosis and ECM degradation, while SPRY1 silencing rescued the impacts.

CONCLUSION

Circ_0110251 protected chondrocytes from IL-1β-induced apoptosis and ECM degradation in OA via sponging miR-3189-3p and elevating SPRY1.

SPRY1 promotes cell proliferation and inhibits apoptosis by activating Hedgehog pathway in acute myeloid leukemia

OBJECTIVE

The aim of this study was to determine the biological function of Sprouty 1 (SPRY1) on acute myeloid leukemia (AML), and to investigate the potential mechanism.

METHODS

The expression of SPRY1 and the prognostic values of SPRY1 were assessed through the analysis of the Cancer Genome Atlas. Meanwhile, the expression of SPRY1 in AML cells was determined by qRT-PCR and western blot. Then, the biological function of SPRY1 on the proliferation, cell cycle and apoptosis in K-562 and HL-60 cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony-formation assay, 5-ethynyl-20-deoxyuridine assay and flow cytometry. Additionally, the protein expressions were measured by western blot.

RESULTS

We found that SPRY1 was markedly overexpressed in the cells of the patients with AML, and the patients with AML having a high SPRY1 expression has a bad prognosis. The proliferation and cell cycle progression in K-562 and HL-60 cells were notably promoted by SPRY1 overexpression, but inhibited by SPRY1 knockdown. Meanwhile, the apoptosis of K-562 and HL-60 cells was significantly repressed by SPRY1 overexpression and facilitated by SPRY1 knockdown. In addition, we found that SPRY1 overexpression significantly activated the Hedgehog pathway in AML cells. The function of SPRY1 on the proliferation, cell cycle and apoptosis was reversed by Gli1 in K-562 and HL-60 cells.

DISCUSSION

Identifying new biomarkers and exploring the pathogenesis of AML is urgent to improve the disease surveillance for patients with AML.

CONCLUSIONS

SPRY1 could facilitate cell proliferation and cell cycle progression, and suppress cell apoptosis via activating the Hedgehog pathway in AML.

Circ_0020093 ameliorates IL-1β-induced apoptosis and extracellular matrix degradation of human chondrocytes by upregulating SPRY1 via targeting miR-23b

Osteoarthritis (OA) is a chronic disease characterized by articular cartilage degeneration and uncontrolled chondrocyte apoptosis. At present, accumulating evidence introduces that circular RNA (circRNA) is involved in the development of OA. The aim of our study was to explore the role and the functional mechanism of circ_0020093 in OA cell model. Human chondrocytes were treated with interleukin-1 beta (IL-1β) to construct OA model. The expression of circ_0020093, miR-23b, and Sprouty 1 (SPRY1) mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell apoptosis was assessed by flow cytometry assay. The expression of extracellular matrix (ECM)-associated markers and SPRY1 protein level was detected by qRT-PCR and Western blot. Bioinformatics analysis-predicted relationship between miR-23b and circ_0020093 or SPRY1 was further verified by dual-luciferase reporter assay and RNA pull-down assay. In this study, we found that the expression of circ_0020093 and SPRY1 was declined, while miR-23b expression was elevated in IL-1β-treated chondrocytes. IL-1β induced chondrocyte apoptosis and ECM degradation, while these negative effects were alleviated by circ_0020093 overexpression or miR-23b inhibition. MiR-23b was a target of circ_0020093, and SPRY1 was a downstream target of miR-23b. Rescue experiments showed that miR-23b enrichment reversed the role of circ_0020093 overexpression, and SPRY1 knockdown also reversed the effects of miR-23b inhibition. Importantly, circ_0020093 positively regulated SPRY1 expression by targeting miR-23b. In conclusion, circ_0020093 ameliorates IL-1β-induced apoptosis and ECM degradation of human chondrocytes by regulating the miR-23b/SPRY1 axis.

Vildagliptin Attenuates Myocardial Dysfunction and Restores Autophagy via miR-21/SPRY1/ERK in Diabetic Mice Heart

Aim: Vildagliptin (vild) improves diastolic dysfunction and is associated with a lower relative risk of major adverse cardiovascular events in younger patients. The present study aimed to evaluate whether vild prevents the development of diabetic cardiomyopathy in type 2 diabetic mice and identify its underlying mechanisms. Methods: Type 2 diabetic mouse model was generated using wild-type (WT) (C57BL/6J) and miR-21 knockout mice by treatment with HFD/STZ. Cardiomyocyte-specific miR-21 overexpression was achieved using adeno-associated virus 9. Echocardiography was used to evaluate cardiac function in mice. Morphology, autophagy, and proteins levels in related pathway were analyzed. qRT-PCR was used to detect miR-21. Rat cardiac myoblast cell line (H9c2) cells were transfected with miR-21 mimics and inhibitor to explore the related mechanisms of miR-21 in diabetic cardiomyopathy. Results: Vild restored autophagy and alleviated fibrosis, thereby enhancing cardiac function in DM mice. In addition, miR-21 levels were increased under high glucose conditions. miR-21 knockout DM mice with miR-21 knockout had reduced cardiac hypertrophy and cardiac dysfunction compared to WT DM mice. Overexpression of miR-21 aggravated fibrosis, reduced autophagy, and attenuated the protective effect of vild on cardiac function. In high-glucose-treated H9c2 cells, the downstream effectors of sprouty homolog 1 (SPRY1) including extracellular signal-regulated kinases (ERK) and mammalian target of rapamycin showed significant changes following transfection with miR-21 mimics or inhibitor. Conclusion: The results of our study indicate that vild prevents DCM by restoring autophagy through the miR-21/SPRY1/ERK/mTOR pathway. Therefore, miR-21 is a target in the development of DCM, and vild demonstrates significant potential for clinical application in prevention of DCM.

A Novel Locus and Candidate Gene for Familial Developmental Dyslexia on Chromosome 4q

Objective: Developmental dyslexia is a highly heritable specific reading and writing disability. To identify a possible new locus and candidate gene for this disability, we investigated a four-generation pedigree where transmission of dyslexia is consistent with an autosomal dominant inheritance pattern. Methods: We performed genome wide array-based SNP genotyping and parametric linkage analysis and sequencing analysis of protein-coding exons, exon-intron boundaries and conserved extragenic regions within the haplotype cosegregating with dyslexia in DNA from one affected and one unaffected family member. Cosegregation was confirmed by sequencing all available family members. Additionally, we analyzed 96 dyslexic individuals who had previously shown positive LOD scores on chromosome 4q28 as well as an even larger sample (n = 2591). Results: We found a single prominent linkage interval on chromosome 4q, where sequence analysis revealed a nucleotide variant in the 3' UTR of brain expressed SPRY1 in the dyslexic family member that cosegregated with dyslexia. This sequence alteration might affect the binding efficiency of the IGF2BP1 RNA-binding protein and thus influence the expression level of the SPRY1 gene product. An analysis of 96 individuals from a cohort of dyslexic individuals revealed a second heterozygous variant in this gene, which was absent in the unaffected sister of the proband. An investigation of the region in a much larger sample further found a nominal p-value of 0.0016 for verbal short-term memory (digit span) in 2,591 individuals for a neighboring SNV. After correcting for the local number of analyzed SNVs, and after taking into account linkage disequilibrium, we found this corresponds to a p-value of 0.0678 for this phenotype. Conclusions: We describe a new locus for familial dyslexia and discuss the possibility that SPRY1 might play a role in the etiology of a monogenic form of dyslexia.

Overexpression of sprouty 1 protein in human oral squamous cell carcinogenesis

Abstract Background/purpose

Sprouty (SPRY) has four isoforms, SPRY1–4, and its deficiency produces haphazard ‘sprouting’ of tracheal tubules. This study investigated SPRY1 protein expression in human oral potentially malignant disorders (OPMDs) and oral squamous cell carcinomas (OSCCs).

Materials and methods

90 OSCCs, 10 OPMDs with malignant transformation (MT), 17 OPMDs without MT, and six normal oral mucosa (NOM) tissue samples were subjected to immunohistochemical staining. Three human oral cancer cell lines (OCCLs), an oral precancer cell line (DOK), and a primary culture of normal oral keratinocytes (HOK) were used for western blotting.

Results

Significantly increased expression of SPRY1 protein from NOM and OPMD without MT to OSCC was observed. The protein expressions of SPRY1 in OCCLs were significantly enhanced as compared with DOK and HOK. Increased phosphor/total-ERK expression was observed in OCCLs as compared with HOK. A significantly increased SPRY1 protein level was noted in OPMDs with MT as compared with those without MT, in addition to a significant increase in DOK in comparison with HOK.

Conclusion

Our results indicated that overexpression of SPRY1 protein is potentially associated with human oral squamous cell carcinogenesis.

MicroRNA-21-3p accelerates diabetic wound healing in mice by downregulating SPRY1

A variety of novel drugs and advanced therapeutic strategies have been developed for diabetic foot ulcers (DFUs); however, the clinical outcomes are unsatisfactory and the underlying mechanisms of DFU remain elusive. MicroRNAs (miRNA) regulate the pathological processes of many diseases. Fibroblasts are involved in each stage of wound healing, and the functions of fibroblasts may be regulated by miRNAs. In the present study, we found that the levels of miRNA-21-3p (miR-21-3p) were decreased in patients with diabetes as compared with those in the healthy control. Similarly, the level of miRNA-21-3p was decreased in fibroblasts that were stimulated with D-glucose as compared with that in the control fibroblasts. Furthermore, enhanced function was found in fibroblasts followed by the miR-21-3p agonist treatment, and a rapid wound healing process was achieved in the miR-21-3p agonist-treated mice. MiR-21-3p directly targeted protein sprout homolog 1 (SPRY1), and the miR-21-3p-regulated reduction in SPRY1 enhanced the function of fibroblasts and accelerated wound healing in vivo. These findings suggest that miR-21-3p may treat DFU by reducing SPRY1.

MicroRNA-21-5p participates in IgA nephropathy by driving T helper cell polarization

BACKGROUND

Previous studies have revealed abnormal lymphocyte subsets in IgA nephropathy (IgAN). Some microRNAs have been reported to influence T helper differentiation. Here, we explored the underlying mechanism regarding how miRNAs regulate lymphocyte subsets in IgAN.

METHODS

First, miRNA and mRNA profiles in PBMCs from IgAN patients and controls were obtained by next-generation sequencing and gene expression array. The target miRNAs and mRNAs were identified through combined analysis. Then, in an independent population, we detected the expression of target miRNA in CD3⁺ T cells and CD19⁺ B cells. Next, we detected T helper cell subgroups and plasma IgA1 levels in another independent population and analyzed the correlations between them.

RESULTS

In total, 22 differentially expressed miRNAs were identified between IgAN patients and controls. Among them, microRNA-21-5p (miR-21) showed the highest expression, and SPRY1, SPRY2, and FASLG were chosen as miR-21 target genes. Then, we confirmed elevated miR-21 levels in CD3⁺ T cells of IgAN patients. Accordingly, decreased mRNA levels of SPRY1, SPRY2, and FASLG were found, and miR-21 showed a significant negative correlation with SPRY1 levels in CD3⁺ T cells of IgAN patients. Finally, we revealed that the proportion of Th17 cells was significantly elevated in IgAN patients and negatively correlated with SPRY1 expression. Furthermore, the proportion of Th17 cells showed a positive correlation trend with plasma IgA1 levels.

CONCLUSIONS

Our results suggested that in IgAN, the upregulated miR-21 expression in T lymphocytes inhibited SPRY1 expression and thereby induced Th17 polarization, which might influence the characteristic feature of IgA1 overproduction in IgAN patients.

lncRNA UCA1 Predicts a Poor Prognosis and Regulates Cell Proliferation and Migration by Repressing p21 and SPRY1 Expression in GC

Dysregulated expression of long non-coding RNAs (lncRNAs) has been reported in many types of cancers, indicating that it has important regulatory roles in human cancer biology. Recently, lncRNA urothelial cancer-associated 1 (UCA1) was shown to be dysregulated in many cancer types, but the detailed mechanisms remain largely unknown. In our study, we found that upregulated UCA1 is associated with poor prognosis in gastric cancer patients. Further experiments revealed that UCA1 knockdown significantly repressed the proliferation and migration both in vitro and in vivo. Moreover, RNA sequencing (RNA-seq) analysis revealed that UCA1 knockdown preferentially affected genes that are linked to cell proliferation, cell cycle, and cell migration. Mechanistically, UCA1 promotes cell proliferation progression through repressing p21 and Sprouty RTK signaling antagonist 1 (SPRY1) expression by binding to EZH2. We found that UCA1 could mediate the trimethylation of H3K27 in promoters of p21 and SPRY1. To our knowledge, this is the first report showing the global gene profile of downstream targets of UCA1 in the progression of gastric cancer. Collectively, our data reveal the important roles of UCA1 in gastric cancer (GC) oncogenesis.

Mechanism of SPRY1 methylation regulating natural aging of skin epidermal cells

OBJECTIVE

To investigate the relationship among natural aging of epidermal cells, epigenetics, and SPRY1 methylation mechanism.

METHODS

Immunohistochemistry, reverse transcription-PCR (RT-PCR), and Western blot were used to detect the expression of DNA methyltransferase 1 (DNMT1) and Sprouty1 (SPRY1) in skin epithelial cells from different age groups. An aging model of HaCaT cells was constructed. In HaCaT cells and their aging groups, DNMT1 and SPRY1 expression were detected by RT-PCR and WB. SPRY1 methylation status in epidermal cells from different age groups and HaCaT cells were detected by Methylation-Specific PCR (MS-PCR).

RESULTS

The expression of DNMT1 and SPRY1 in skin epithelial cells from natural aging groups decreased with age; there was no significant difference in the expression of DNMT1 in HaCaT cells and the different age groups. The expression of SPRY1 in HaCaT cells was lower than it was in the aging groups. The methylation status of SPRY1 gradually decreased as the age of skin epidermal cells increased, while the methylation status of SPRY1 was not different between HaCaT cells and the aging group.

CONCLUSION

DNMT1 is involved in the regulation of natural aging of skin epidermal cells but has a nominal role in our induced aging model. SPRY1 is involved in natural aging and induced aging of skin epidermal cells. The regulation of SPRY1 methylation is involved in the natural senescence of skin epidermal cells, while the induced aging of epidermal cells is nominally involved in the mechanism of SPRY1 methylation.

High FREM2 Gene and Protein Expression Are Associated with Favorable Prognosis of IDH-WT Glioblastomas

World Health Organization grade IV diffuse gliomas, known as glioblastomas, are the most common malignant brain tumors, and they show poor prognosis. Multimodal treatment of surgery followed by radiation and chemotherapy is not sufficient to increase patient survival, which is 12 to 18 months after diagnosis. Despite extensive research, patient life expectancy has not significantly improved over the last decade. Previously, we identified FREM2 and SPRY1 as genes with differential expression in glioblastoma cell lines compared to nonmalignant astrocytes. In addition, the FREM2 and SPRY1 proteins show specific localization on the surface of glioblastoma cells. In this study, we explored the roles of the FREM2 and SPRY1 genes and their proteins in glioblastoma pathology using human tissue samples. We used proteomic, transcriptomic, and bioinformatics approaches to detect changes at different molecular levels. We demonstrate increased FREM2 protein expression levels in glioblastomas compared to reference samples. At the transcriptomic level, both FREM2 and SPRY1 show increased expression in tissue samples of different glioma grades compared to nonmalignant brain tissue. To broaden our experimental findings, we analyzed The Cancer Genome Atlas glioblastoma patient datasets. We discovered higher FREM2 and SPRY1 gene expression levels in glioblastomas compared to lower grade gliomas and reference samples. In addition, we observed that low FREM2 expression was associated with progression of IDH-mutant low-grade glioma patients. Multivariate analysis showed positive association between FREM2 and favorable prognosis of IDH-wild type glioblastoma. We conclude that FREM2 has an important role in malignant progression of glioblastoma, and we suggest deeper analysis to determine its involvement in glioblastoma pathology.

Sprouty1 regulates neuritogenesis and survival of cortical neurons

In multicellular organisms, receptor tyrosine kinases (RTKs) control a variety of cellular processes, including cell proliferation, differentiation, migration, and survival. Sprouty (SPRY) proteins represent an important class of ligand-inducible inhibitors of RTK-dependent signaling pathways. Here, we investigated the role of SPRY1 in cells of the central nervous system (CNS). Expression of SPRY1 was substantially higher in neural stem cells than in cortical neurons and was increased during neuronal differentiation of cortical neurons. We found that SPRY1 was a direct target gene of the CNS-specific microRNA, miR-124 and miR-132. In primary cultures of cortical neurons, the neurotrophic factors brain-derived neurotrophic factor (BDNF) and Basic fibroblast growth factor (FGF2) downregulated SPRY1 expression to positively regulate their own functions. In immature cortical neurons and mouse N₂ A cells, we found that overexpression of SPRY1 inhibited neurite development, whereas knockdown of SPRY1 expression promoted neurite development. In mature neurons, overexpression of SPRY1 inhibited the prosurvival effects of both BDNF and FGF2 on glutamate-mediated neuronal cell death. SPRY1 was also upregulated upon glutamate treatment in mature neurons and partially contributed to the cytotoxic effect of glutamate. Together, our results indicate that SPRY1 contributes to the regulation of CNS functions by influencing both neuronal differentiation under normal physiological processes and neuronal survival under pathological conditions.

Meta-Analysis and Experimental Validation Identified FREM2 and SPRY1 as New Glioblastoma Marker Candidates

Glioblastoma (GB) is the most aggressive brain malignancy. Although some potential glioblastoma biomarkers have already been identified, there is a lack of cell membrane-bound biomarkers capable of distinguishing brain tissue from glioblastoma and/or glioblastoma stem cells (GSC), which are responsible for the rapid post-operative tumor reoccurrence. In order to find new GB/GSC marker candidates that would be cell surface proteins (CSP), we have performed meta-analysis of genome-scale mRNA expression data from three data repositories (GEO, ArrayExpress and GLIOMASdb). The search yielded ten appropriate datasets, and three (GSE4290/GDS1962, GSE23806/GDS3885, and GLIOMASdb) were used for selection of new GB/GSC marker candidates, while the other seven (GSE4412/GDS1975, GSE4412/GDS1976, E-GEOD-52009, E-GEOD-68848, E-GEOD-16011, E-GEOD-4536, and E-GEOD-74571) were used for bioinformatic validation. The selection identified four new CSP-encoding candidate genes—CD276, FREM2, SPRY1, and SLC47A1—and the bioinformatic validation confirmed these findings. A review of the literature revealed that CD276 is not a novel candidate, while SLC47A1 had lower validation test scores than the other new candidates and was therefore not considered for experimental validation. This validation revealed that the expression of FREM2—but not SPRY1—is higher in glioblastoma cell lines when compared to non-malignant astrocytes. In addition, FREM2 gene and protein expression levels are higher in GB stem-like cell lines than in conventional glioblastoma cell lines. FREM2 is thus proposed as a novel GB biomarker and a putative biomarker of glioblastoma stem cells. Both FREM2 and SPRY1 are expressed on the surface of the GB cells, while SPRY1 alone was found overexpressed in the cytosol of non-malignant astrocytes.

MiR-338-5p Promotes Inflammatory Response of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via Targeting SPRY1

Our purpose is to study the roles of microRNA-338-5p (miR-338-5p) on the proliferation, invasion, and inflammatory response of fibroblast-like synoviocytes (SFs) in rheumatoid arthritis patients by regulating SPRY1. The target relationship between miR-338-5p and SPRY1 was validated through luciferase reporter system. The expression of miR-338-5p and SPRY1 in synovial tissues and synovial cells were detected using RT-PCR and western blot. The mimics and inhibitors of miR-338-5p were transfected into SFs. MTT, Transwell, and ELISA assays were used to analyze cell proliferation, invasiveness, and the secreted extracellular pro-inflammatory cytokines (such as IL-1a, IL-6, COX2) levels of SFs. MiR-338-5p was highly expressed in rheumatoid arthritis tissues and cells, and directly down-regulated the expression of SPRY1 in the SFs of rheumatoid arthritis patients. Cell proliferation, invasiveness and the expression level of pro-inflammatory cytokines in synovial cells increased after the transfection of miR-338-5p mimics, while the proliferation, invasion and expression level of pro-inflammatory cytokines decreased after the transfection of miR-338-5p inhibitors. In conclusion,miR-338-5p promoted the proliferation, invasion and inflammatory reaction in SFs of rheumatoid arthritis by directly down-regulating SPRY1 expression. J. Cell. Biochem. 118: 2295-2301, 2017. © 2017 Wiley Periodicals, Inc.

MicroRNA-21 regulates the ERK/NF-κB signaling pathway to affect the proliferation, migration, and apoptosis of human melanoma A375 cells by targeting SPRY1, PDCD4, and PTEN

This study aims to explore the effects of microRNA-21 (miR-21) and ERK/NF-κB signaling pathway on human melanoma A375 cells. The melanoma tissues and adjacent normal tissues were obtained from 45 melanoma patients. qRT-PCR was conducted to quantify the expression of miR-21 and the gene mRNA expressions. Human melanoma A375 cells were divided into the Mock, negative control (NC), miR-21 inhibitors, miR-21 inhibitors + siRNA-SPRY1, miR-21 inhibitors + siRNA-PDCD4, and miR-21 inhibitors + siRNA-PTEN groups. Western blotting was used to determine protein expressions. CCK8 assay and Transwell assay were performed to evaluate the proliferation, migration, and invasion of A375 cells. Annexin V/propidium iodide double staining was adopted to detect cell apoptosis. MiR-21 expression was higher in melanoma tissues than in adjacent tissues, while the mRNA and protein expressions of SPRY1, PDCD4, and PTEN were lower in melanoma tissues than in adjacent tissues. Compared with the Mock and NC groups, the miR-21 inhibitors group exhibited increased expressions of SPRY1, PDCD4, and PTEN and decreased expressions of ERK, p-ERK, NF-κB p65, and p-NF-κB p65. After transfection of miR-21 inhibitors, the proliferation, migration, and invasion of A375 cells were inhibited, while the apoptosis of A375 cells was promoted. However, the effects of miR-21 inhibitors on the growth, migration, invasion, and apoptosis of A375 cells were reversed after transfection of siRNA-SPRY1, siRNA-PDCD4, or siRNA-PTEN. MiR-21 can promote the proliferation, migration, and inhibit the apoptosis of human melanoma A375 cells by inhibiting SPRY1, PDCD4, and PTEN via ERK/NF-κB signaling pathway. © 2016 Wiley Periodicals, Inc.

Two locus inheritance of non-syndromic midline craniosynostosis via rare SMAD6 and common BMP2 alleles

Premature fusion of the cranial sutures (craniosynostosis), affecting 1 in 2000 newborns, is treated surgically in infancy to prevent adverse neurologic outcomes. To identify mutations contributing to common non-syndromic midline (sagittal and metopic) craniosynostosis, we performed exome sequencing of 132 parent-offspring trios and 59 additional probands. Thirteen probands (7%) had damaging de novo or rare transmitted mutations in SMAD6, an inhibitor of BMP – induced osteoblast differentiation (p<10⁻²⁰). SMAD6 mutations nonetheless showed striking incomplete penetrance (<60%). Genotypes of a common variant near BMP2 that is strongly associated with midline craniosynostosis explained nearly all the phenotypic variation in these kindreds, with highly significant evidence of genetic interaction between these loci via both association and analysis of linkage. This epistatic interaction of rare and common variants defines the most frequent cause of midline craniosynostosis and has implications for the genetic basis of other diseases.

DOI:http://dx.doi.org/10.7554/eLife.20125.001

The bones in the front, back and sides of the human skull are not fused to one another at birth in order to allow the brain to double in size during the first year of life and continue growing into adulthood. However, one in 2,000 infants is born with a condition called craniosynostosis in which some of these bones have already fused. This fusion prevents the skull from growing properly, and can lead to the brain becoming compressed. As such, surgeons routinely undo the fusion in these infants to allow the brain and skull to grow normally.

Eighty-five percent of craniosynostosis cases occur in infants with no other abnormalities, (called non-syndromic cases) and most have no other affected family member. It has therefore been unclear whether these infants have craniosynostosis due to a genetic or non-genetic cause. If the cause is genetic, it is also not clear whether a mutation in a single gene, the combined effects of many genes, or something in between is responsible.

Now, by focusing on a group of 191 infants with premature fusion of bones joined at the midline of the skull, Timberlake et al. asked if any of the approximately 20,000 genes in the human genome were altered more frequently in these infants than would be expected by chance. This search revealed that rare mutations that disable one copy of a gene called SMAD6 in combination with a common DNA variant near another gene called BMP2 account for about 7% of infants with midline forms of craniosynostosis. These genes are both known to regulate how bones form, which explains how the mutation of these genes could lead to craniosynostosis.

In all cases, the parents of these children were unaffected. This was typically because one parent had only the SMAD6 mutation while the other had only the common BMP2 variant; the transmission of both to their offspring resulted in craniosynostosis. The finding that a rare mutation’s effect is strongly modified by a common variant from another site in the genome is unprecedented. These findings will allow doctors to counsel families about the risk of having additional children with craniosynostosis.

Timberlake et al. next plan to study more patients with craniosynostosis to identify additional genes that contribute to this disease. They will also look at other diseases to see whether the combination of rare mutation and common DNA variant could be behind other unexplained disorders.

DOI:http://dx.doi.org/10.7554/eLife.20125.002

Expansion of the RASopathies

The Ras/mitogen activated protein kinase (MAPK) pathway is essential in the regulation of cell cycle, differentiation, growth, cell senescence and apoptosis, all of which are critical to normal development. A class of neurodevelopmental disorders, RASopathies, is caused by germline mutations in genes of the Ras/MAPK pathway. Through the use of whole exome sequencing and targeted sequencing of selected genes in cohorts of panel-negative RASopathy patients, several new genes have been identified. These include: RIT1, SOS2, RASA2, RRAS and SYNGAP1, that likely represent new, albeit rare, causative RASopathy genes. In addition, A2ML1, LZTR1, MYST4, SPRY1 and MAP3K8 may represent new rare genes for RASopathies, but, additional functional studies regarding the mutations are warranted. In addition, recent reports have demonstrated that chromosomal copy number variation in regions encompassing Ras/MAPK pathway genes may be a novel pathogenetic mechanism expanding the RASopathies.

Tumor-specifically hypoxia-induced therapy of SPRY1/2 displayed differential therapeutic efficacy for melanoma

Activation of receptor tyrosine kinase (RTK) signalling pathways is frequently correlated to cancer cell proliferation, angiogenesis and cell survival. Sprouty (SPRY) proteins function as a physiological endogenous inhibitor of RTK signalling pathways, have been shown to be deregulated in most cancer cells. Here, we demonstrated that over-expression of SPRY1 and SPRY2 inhibited B16F10 cell proliferation through G1 phase arrest in vitro, and SPRY2 showed more potent inhibitory effects than SPRY1. In order to tumor-specific delivery of SPRY1/2 in vivo, two strains of attenuated Salmonella typhimurium VNP20009 (VNP-PQE-SPRY1 and VNP-PQE-SPRY2) were constructed to specifically express SPRY1 or SPRY2 under the control of a hypoxia-induced nirB promoter. The efficiency and specificity of the recombinant strains were validated in both bacteria and animal tumor models. SPRY1 and SPRY2 gene could be specifically driven by the nirB promoter under hypoxia, but not normoxia conditions. In addition, the tumor-targeting ability of VNP-PQE-SPRY1 or VNP-PQE-SPRY2 was similar with VNP. VNP-PQE-SPRY2 significantly suppressed melanoma growth in vivo, suggesting that SPRY2 is a more efficient agent for melanoma therapy. Moreover, the antitumor effect of VNP-SPRY2 is mainly mediated through the inhibition of ERK1/2 phosphorylation, which leads to the inhibition of proliferation in melanoma. Taken together, our results indicated that SPRY2 displayed more potent melanoma suppression than SPRY1 both in vitro and in vivo, and the hypoxia-induced tumor-specific gene therapy of SPRY2 delivered by VNP20009 is a promising strategy for melanoma therapy.

SPRY1 promotes the degradation of uPAR and inhibits uPAR-mediated cell adhesion and proliferation

Urokinase plasminogen activator receptor (uPAR) is a GPI anchored cell surface protein that is closely associated with invasion, migration, and metastasis of cancer cells. Many functional extracellular proteins and transmembrane receptors interact with uPAR. However, few studies have examined the association of uPAR with cytoplasm proteins. We previously used yeast two-hybrid screening to isolate several novel uPAR-interacting cytoplasmic proteins, including Sprouty1 (SPRY1), an inhibitor of the (Ras-mitogen-activated protein kinase) MAPK pathway. In this study, we show that SPRY1 interacts with uPAR and directs it toward lysosomal-mediated degradation. Overexpression of SPRY1 decreased the cell surface and cytoplasmic uPAR protein level. Moreover, SPRY1 overexpression augmented uPAR-induced cell adhesion to vitronectin as well as proliferation of cancer cells. Our results also further support the critical role of SPRY1 contribution to tumor growth. In a subcutaneous tumor model, overexpression of SPRY1 in HCT116 or A549 xenograft in athymic nude mice led to great suppression of tumor growth. These results show that SPRY1 may affect tumor cell function through direct interaction with uPAR and promote its lysosomal degradation.

Docosahexaenoic acid reverses angiotensin II-induced RECK suppression and cardiac fibroblast migration

The omega-3 polyunsaturated fatty acids (ω-3 fatty acids) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to inhibit or delay the progression of cardiovascular diseases, including myocardial fibrosis. Recently we reported that angiotensin II (Ang II) promotes cardiac fibroblast (CF) migration by suppressing the MMP regulator reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), through a mechanism dependent on AT1, ERK, and Sp1. Here we investigated the role of miR-21 in Ang II-mediated RECK suppression, and determined whether the ω-3 fatty acids reverse these effects. Ang II induced miR-21 expression in primary mouse cardiac fibroblasts (CFs) via ERK-dependent AP-1 and STAT3 activation, and while a miR-21 inhibitor reversed Ang II-induced RECK suppression, a miR-21 mimic inhibited both RECK expression and Ang II-induced CF migration. Moreover, Ang II suppressed the pro-apoptotic PTEN, and the ERK negative regulator Sprouty homologue 1 (SPRY1), but induced the metalloendopeptidase MMP2, all in a manner that was miR-21-dependent. Further, forced expression of PTEN inhibited Akt phosphorylation, Sp1 activation, and MMP2 induction. Notably, while both EPA and DHA reversed Ang II-mediated RECK suppression, DHA appeared to be more effective, and reversed Ang II-induced miR-21 expression, RECK suppression, MMP2 induction, and CF migration. These results indicate that Ang II-induced CF migration is differentially regulated by miR-21-mediated MMP induction and RECK suppression, and that DHA has the potential to upregulate RECK, and therefore may exert potential beneficial effects in cardiac fibrosis.

Myocardial and circulating levels of microRNA-21 reflect left ventricular fibrosis in aortic stenosis patients

BACKGROUND

Various human cardiovascular pathophysiological conditions associate aberrant expression of microRNAs (miRNAs) and circulating miRNAs are emerging as promising biomarkers. In mice, myocardial miR-21 overexpression is related to cardiac fibrosis elicited by pressure overload. This study was designed to determine the role of myocardial and plasmatic miR-21 in the maladaptive remodeling of the extracellular matrix induced by pressure overload in aortic stenosis (AS) patients and the clinical value of miR-21 as a biomarker for pathological myocardial fibrosis.

METHODS

In left ventricular biopsies from 75 AS patients and 32 surgical controls, we quantified the myocardial transcript levels of miR-21, miR-21-targets and ECM- and TGF-β-signaling-related elements. miR-21 plasma levels were determined in 25 healthy volunteers and in AS patients. In situ hybridization of miR-21 was performed in myocardial sections.

RESULTS

The myocardial and plasma levels of miR-21 were significantly higher in the AS patients compared with the controls and correlated directly with the echocardiographic mean transvalvular gradients. miR-21 overexpression was confined to interstitial cells and absent in cardiomyocytes. Using bootstrap validated multiple linear regression, the variance in myocardial collagen expression was predicted by myocardial miR-21 (70% of collagen variance) or plasma miR-21 (52% of collagen variance), together with the miR-21 targets RECK and PDCD4, and effectors of TGF-ß signaling.

CONCLUSIONS

Our results support the role of miR-21 as a regulator of the fibrotic process that occurs in response to pressure overload in AS patients and underscore the value of circulating miR-21 as a biomarker for myocardial fibrosis.