Expression of Eya1 in mouse taste buds.

Taste substances are detected by taste receptor cells in the taste buds in the oral epithelium. Individual taste receptor cells contribute to evoking one of the five taste qualities: sweet, umami, bitter, sour, and salty (sodium). They are continuously replaced every few weeks by new ones generated from local epithelial stem cells. A POU transcription factor, Pou2f3 (also known as Skn-1a), regulates the generation and differentiation of sweet, umami, and bitter cells. However, the molecular mechanisms underlying terminal differentiation into these Pou2f3-dependent taste receptor cells remain unknown. To identify the candidate molecules that regulate the differentiation of these taste receptor cells, we searched for taste receptor type-specific transcription factors using RNA-sequence data of sweet and bitter cells. No transcription factor gene showing higher expression in sweet cells than in bitter cells was found. Eyes absent 1 (Eya1) was identified as the only transcription factor gene showing higher expression in bitter cells than in sweet cells. In situ hybridization revealed that Eya1 was predominantly expressed in bitter cells and also in the putative immature/differentiating taste bud cells in circumvallate and fungiform papillae and soft palate. Eya1 is a candidate molecule that regulates the generation and differentiation of bitter cells.

Dual-specificity phosphatase 4 is upregulated during skeletal muscle atrophy and modulates extracellular signal-regulated kinase activity.

Skeletal muscle atrophy results from disparate physiological conditions, including denervation, corticosteroid treatment, and aging. The purpose of this study was to describe and characterize the function of dual-specificity phosphatase 4 (Dusp4) in skeletal muscle after it was found to be induced in response to neurogenic atrophy. Quantitative PCR and Western blot analysis revealed that Dusp4 is expressed during myoblast proliferation but rapidly disappears as muscle cells differentiate. The Dusp4 regulatory region was cloned and found to contain a conserved E-box element that negatively regulates Dusp4 reporter gene activity in response to myogenic regulatory factor expression. In addition, the proximal 3'-untranslated region of Dusp4 acts in an inhibitory manner to repress reporter gene activity as muscle cells progress through the differentiation process. To determine potential function, Dusp4 was fused with green fluorescent protein, expressed in C2C12 cells, and found to localize to the nucleus of proliferating myoblasts. Furthermore, Dusp4 overexpression delayed C2C12 muscle cell differentiation and resulted in repression of a MAP kinase signaling pathway reporter gene. Ectopic expression of a Dusp4 dominant negative mutant blocked muscle cell differentiation and attenuated MAP kinase signaling by preferentially targeting the ERK1/2 branch, but not the p38 branch, of the MAP kinase signaling cascade in skeletal muscle cells. The findings presented in this study provide the first description of Dusp4 in skeletal muscle and suggest that Dusp4 may play an important role in the regulation of muscle cell differentiation by regulating MAP kinase signaling.

PRL-3 Promotes Ubiquitination and Degradation of AURKA and Colorectal Cancer Progression via Dephosphorylation of FZR1.

The oncogenic phosphatase PRL-3 is highly expressed in metastatic colorectal cancer but not in nonmetastatic colorectal cancer or noncolorectal cancer metastatic cancers. Although the proinvasive capacity of PRL-3 has been validated in multiple types of cancer, its impact on colorectal cancer progression and the underlying mechanisms remain poorly understood. Here, we report that overexpressed PRL-3 stimulates G2-M arrest, chromosomal instability (CIN), self-renewal, and growth of colorectal cancer cells in xenograft models, while colorectal cancer cell proliferation is decreased. PRL-3-induced G2-M arrest was associated with decreased expression of Aurora kinase A (AURKA). PRL-3-promoted slow proliferation, CIN, self-renewal, and growth in xenografts were counteracted by ectopic expression of AURKA. Conversely, knockdown of PRL-3 resulted in low proliferation, S-phase arrest, impaired self-renewal, increased apoptosis, and diminished xenograft growth independently of AURKA. Analysis of colorectal cancer specimens showed that expression of PRL-3 was associated with high status of CIN and poor prognosis, which were antagonized by expression of AURKA. PRL-3 enhanced AURKA ubiquitination and degradation in a phosphatase-dependent fashion. PRL-3 interacted with AURKA and FZR1, a regulatory component of the APC/CFZR1 complex. Destabilization of AURKA by PRL-3 required PRL-3-mediated dephosphorylation of FZR1 and assembly of the APC/CFZR1 complex. Our study suggests that PRL-3-regulated colorectal cancer progression is collectively determined by distinct malignant phenotypes and further reveals PRL-3 as an essential regulator of APC/CFZR1 in controlling the stability of AURKA. SIGNIFICANCE: Dephosphorylation of FZR1 by PRL-3 facilitates the activity of APC/CFZR1 by destabilizing AURKA, thus influencing aggressive characteristics and overall progression of colorectal cancer.

Compound haploinsufficiency of Dok2 and Dusp4 promotes lung tumorigenesis.

Recurrent broad-scale heterozygous deletions are frequently observed in human cancer. Here we tested the hypothesis that compound haploinsufficiency of neighboring genes at chromosome 8p promotes tumorigenesis. By targeting the mouse orthologs of human DOK2 and DUSP4 genes, which were co-deleted in approximately half of human lung adenocarcinomas, we found that compound-heterozygous deletion of Dok2 and Dusp4 in mice resulted in lung tumorigenesis with short latency and high incidence, and that their co-deletion synergistically activated MAPK signaling and promoted cell proliferation. Conversely, restoration of DOK2 and DUSP4 in lung cancer cells suppressed MAPK activation and cell proliferation. Importantly, in contrast to downregulation of DOK2 or DUSP4 alone, concomitant downregulation of DOK2 and DUSP4 was associated with poor survival in human lung adenocarcinoma. Therefore, our findings lend in vivo experimental support to the notion that compound haploinsufficiency, due to broad-scale chromosome deletions, constitutes a driving force in tumorigenesis.

Fungicide resistance toward fludioxonil conferred by overexpression of the phosphatase gene MoPTP2 in Magnaporthe oryzae.

The fungicide fludioxonil causes hyperactivation of the Hog1p MAPK within the high-osmolarity glycerol signaling pathway essential for osmoregulation in pathogenic fungi. The molecular regulation of MoHog1p phosphorylation is not completely understood in pathogenic fungi. Thus, we identified and characterized the putative MoHog1p-interacting phosphatase gene MoPTP2 in the filamentous rice pathogen Magnaporthe oryzae. We found overexpression of MoPTP2 conferred fludioxonil resistance in M. oryzae, whereas the 'loss of function' mutant ΔMoptp2 was more susceptible toward the fungicide. Additionally, quantitative phosphoproteome profiling of MoHog1p phosphorylation revealed lower phosphorylation levels of MoHog1p in the MoPtp2p overexpression mutant compared to the wild-type strain, whereas MoHog1p phosphorylation increased in the ΔMoptp2 mutant. Furthermore, we identified a set of MoHog1p-dependent genes regulated by the MoPtp2p expression level. Our results indicate that the phosphatase MoPtp2p is involved in the regulation of MoHog1p phosphorylation and that overexpression of the gene MoPTP2 is a novel molecular mechanism of fungicide resistance.

miR-219a-5p represses migration and invasion of osteosarcoma cells via targeting EYA2.

EYA2 is the developmental transcription factor and phosphatase, playing an important role in numerous species in regulating cell death and differentiation. Recent studies showed that EYA2 is dysregulated and involved in the progression of various cancers. However, the expression and role of EYA2 in osteosarcoma remains unclear. Here, we found that EYA2 expression was evidently upregulated osteosarcoma (OS) tissue and cell lines. Next, we predicted EYA2-targeting miRNAs, which was further evaluated using a dual luciferase reporter assay. We found that miR-219a-5p significantly repressed EYA2 expression via binding to the 3'-UTR of EYA2. Furthermore, overexpressed miR-219a-5p significantly repressed OS cell invasion and migration, which was reversed by overexpressed EYA2. While silenced miR-219a-5p induced OS cell invasion and migration, which was reversed by silenced EYA2. In conclusion, our study revealed that miR-219a-5p function as tumour suppressor regulates OS cell invasiveness by repressing EYA2 expression.

Up-Regulation of Phosphatase in Regenerating Liver-3 (PRL-3) Contributes to Malignant Progression of Hepatocellular Carcinoma by Activating Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN)/Phosphoinositide 3-Kinase (PI3K)/AKT Signaling Pathway.

BACKGROUND The purpose of the study was to investigate the functional roles of phosphatase in regenerating liver-3 (PRL-3) in hepatocellular carcinoma (HCC), as well as the related molecular mechanisms. MATERIAL AND METHODS HCC tissues and adjacent normal tissues were collected from 124 HCC patients. The mRNA and protein levels of PRL-3 were detected using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays, respectively. The relationship between PRL-3 expression and clinical characteristics of HCC patients was evaluated by chi-square test. MTT and Transwell assays were performed to estimate cell proliferation and motility, respectively. RESULTS The expression of PRL-3 was significantly increased in HCC tissues and cells at both protein and mRNA levels (P<0.01 for all). Furthermore, the up-regulation of PRL-3 was positively correlated with hepatic vascular invasion (P=0.019), lymph node metastasis (P=0.012), and TNM stage (P=0.001). The knockdown of PRL-3 suppressed HCC cell proliferation, migration, and invasion, and PR3K/AKT pathway activity was also obviously inhibited in HCC cells with PRL-3 deficiency. The levels of PTEN were negatively associated with PRL-3 expression. PRL-3 might inhibit the protein level of PTEN through enhancing its phosphorylation level. The transfection of si-PTEN can reverse the anti-tumor action caused by PRL-3 knockdown in HCC cells. CONCLUSIONS Up-regulation of PRL-3 may activate the PI3K/AKT signaling pathway and enhance malignant progression of HCC through targeting PTEN.

Mitogen activated protein kinase 6 and MAP kinase phosphatase 1 are involved in the response of Arabidopsis roots to L-glutamate.

KEY MESSAGE: The function and components of L-glutamate signaling pathways in plants have just begun to be elucidated. Here, using a combination of genetic and biochemical strategies, we demonstrated that a MAPK module is involved in the control of root developmental responses to this amino acid. Root system architecture plays an essential role in plant adaptation to biotic and abiotic factors via adjusting signal transduction and gene expression. L-Glutamate (L-Glu), an amino acid with neurotransmitter functions in animals, inhibits root growth, but the underlying genetic mechanisms are poorly understood. Through a combination of genetic analysis, in-gel kinase assays, detailed cell elongation and division measurements and confocal analysis of expression of auxin, quiescent center and stem cell niche related genes, the critical roles of L-Glu in primary root growth acting through the mitogen-activated protein kinase 6 (MPK6) and the dual specificity serine-threonine-tyrosine phosphatase MKP1 could be revealed. In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu. Mutations in MPK6 or MKP1 reduced or increased root cell division and elongation in response to L-Glu, possibly modulating auxin transport and/or response, but in a PLETHORA1 and 2 independent manner. Our data highlight MPK6 and MKP1 as components of an L-Glu pathway linking the auxin response, and cell division for primary root growth.

PRL­3 increases the aggressive phenotype of prostate cancer cells in vitro and its expression correlates with high-grade prostate tumors in patients.

The increased expression of phosphatase of regenerating liver-3 (PRL­3) has been shown to be associated with the aggressive and metastatic phenotype of different solid tumors. However, it is not known whether PRL­3 plays a similar role in the progression of prostate cancer (PCa). In this study, immunoblot analysis of androgen receptor (AR)-positive PCa lines (LNCaP and LNCaP­SF) revealed the constitutive cytoplasmic expression of PRL­3, and stimulation with R1881 (AR agonist) rapidly increased the nuclear translocation of PRL­3. The AR-negative cell lines exhibited negligible PRL­3 expression, and the ectopic overexpression of PRL­3 increased both the proliferative and invasive potential of PC3 and DU145 cells. In addition, we measured PRL­3 protein expression in human prostate tumor sections. A high-density prostate tumor microarray (TMA) was immunostained to assess whether PRL­3 expression and its subcellular localization (cytoplasmic and nuclear levels) is associated with the Gleason score (GS), Gleason grade (GG) and tumor stage (T-stage). Digital image analysis (DIA) revealed that PRL­3 expression was significantly higher in the malignant cores, as compared to the non­malignant areas. Increases in both total and nuclear PRL­3 levels were also associated with a higher GS and GG. Metastatic tumors (T4­stage) had lower cytoplasmic, but higher nuclear PRL­3 levels. Furthermore, the nuclear/cytoplasmic ratio for PRL­3 in the tumors graded as GS7 could effectively distinguish between indolent (3+4) and aggressive (4+3) disease. Thus, our experiments using PCa lines suggested that PRL­3 is an AR-regulated gene and its androgen-induced nuclear localization may increase the aggressive behavior of PCa cells. Furthermore, the digital analysis of immunostained tumor sections suggested that PRL­3 may be an effective biomarker of high-grade PCa, and its nuclear/cytoplasmic ratio may be used to distinguish between indolent vs. aggressive tumors.

PRL-3/PTP4A3 phosphatase regulates integrin ß1 in adhesion structures during migration of human ocular melanoma cells.

In a previous transcriptomic analysis of 63 ocular melanomas of the uvea, we found that expression of the PRL-3/PTP4A3 gene, encoding a phosphatase that is anchored to the plasma membrane, was associated with the risk of metastasis, and a poor prognosis. We also showed that PRL-3 overexpression in OCM-1 ocular melanoma cells significantly increased cell migration in vitro and invasiveness in vivo, suggesting a direct role for PRL-3 in the metastatic spreading of uveal melanoma. Here, we aimed to identify PRL-3 substrates at the plasma membrane involved in adhesion to the extracellular matrix. We focused on integrin ß1, which is the most highly expressed integrin in our cohort of uveal melanomas. We show that preventing PRL-3 anchorage to the plasma membrane i) abolishes PRL-3-induced migration in OCM-1 cells, ii) specifically enhances the spreading of OCM-1 cells overexpressing PRL-3, and iii) favors the maturation of large focal adhesions (FAs) containing integrin ß1 on collagen I. Knockdown experiments confirmed integrin ß1 involvement in PRL3-induced migration. We identified interactions between PRL-3 and integrin ß1, as well as with FAK P-Y397, an auto-activated form of Focal Adhesion Kinase found in FAs. We also show that integrin ß1 may be dephosphorylated by PRL-3 in its intracytoplasmic S/T region, an important motif for integrin-mediated cell adhesion. Finally, we observed that PRL-3 regulated the clustering of integrin ß1 in FAs on collagen I but not on fibronectin. This work identifies PRL-3 as a new regulator of cell adhesion structures to the extracellular matrix, and further supports PRL-3 as a key actor of metastasis in uveal melanoma, of which molecular mechanisms are still poorly understood.

Susceptibility of naïve and differentiated PC12 cells to Japanese encephalitis virus infection.

Japanese encephalitis is a mosquito-borne disease caused by Japanese encephalitis virus (JEV) infection. Although JEV infects and replicates in cells with multiple tissue origins, neurons are the preferential cells for JEV infection. Currently, the identities of JEV cell tropism are largely unclear. To gain better insight into the underlying identities of JEV cell tropism, this study was designed to compare the JEV cell tropism with naïve or differentiated PC12 cells. Through nerve growth factor-differentiated PC12 cells, we discovered that JEV efficiently replicated in differentiated PC12 cells rather than naïve cells. Mechanistic studies revealed that viral adsorption/attachment seemed not to be a crucial factor. Supporting data showed that antagonizing postreceptor intracellular signaling of interferons, along with the activation of suppressor of cytokine signaling-3 (SOCS3) expression and protein tyrosine phosphatase activity, were apparent in differentiated PC12 cells after JEV infection. Independent of differentiating inducing agents, the upregulation of SOCS3 expression and protein tyrosine phosphatase activity, as well as preferential JEV tropism, were common in JEV-infected differentiated PC12 cells. Using cultured primary neurons, JEV efficiently replicated in embryonic neurons rather than adult neurons, and the preference was accompanied by higher SOCS3 expression and protein tyrosine phosphatase activity. Given that both SOCS3 and protein tyrosine phosphatases have been implicated in the process of neuronal differentiation, JEV infection seems to not only create an antagonizing strategy to escape host's interferon antiviral response but also takes advantage of cellular machinery to favor its replication. Taken together, current findings imply that dynamic changes within cellular regulators of antiviral machinery could be accompanied by events of neuronal differentiation, thus concurrently playing roles in the control of JEV cell tropism and replication. © 2017 IUBMB Life, 69(2):79-87, 2017.

Analyses of differentially expressed genes after exposure to acute stress, acute ethanol, or a combination of both in mice.

Alcohol abuse is a complex disorder, which is confounded by other factors, including stress. In the present study, we examined gene expression in the hippocampus of BXD recombinant inbred mice after exposure to ethanol (NOE), stress (RSS), and the combination of both (RSE). Mice were given an intraperitoneal (i.p.) injection of 1.8 g/kg ethanol or saline, and subsets of both groups were exposed to acute restraint stress for 15 min or controls. Gene expression in the hippocampus was examined using microarray analysis. Genes that were significantly (p < 0.05, q < 0.1) differentially expressed were further evaluated. Bioinformatic analyses were predominantly performed using tools available at GeneNetwork.org, and included gene ontology, presence of cis-regulation or polymorphisms, phenotype correlations, and principal component analyses. Comparisons of differential gene expression between groups showed little overlap. Gene Ontology demonstrated distinct biological processes in each group with the combined exposure (RSE) being unique from either the ethanol (NOE) or stress (RSS) group, suggesting that the interaction between these variables is mediated through diverse molecular pathways. This supports the hypothesis that exposure to stress alters ethanol-induced gene expression changes and that exposure to alcohol alters stress-induced gene expression changes. Behavior was profiled in all groups following treatment, and many of the differentially expressed genes are correlated with behavioral variation within experimental groups. Interestingly, in each group several genes were correlated with the same phenotype, suggesting that these genes are the potential origins of significant genetic networks. The distinct sets of differentially expressed genes within each group provide the basis for identifying molecular networks that may aid in understanding the complex interactions between stress and ethanol, and potentially provide relevant therapeutic targets. Using Ptp4a1, a candidate gene underlying the quantitative trait locus for several of these phenotypes, and network analyses, we show that a large group of differentially expressed genes in the NOE group are highly interrelated, some of which have previously been linked to alcohol addiction or alcohol-related phenotypes.

Germline recombination in a novel Cre transgenic line, Prl3b1-Cre mouse.

Spermatogenesis is a complex and highly regulated process by which spermatogonial stem cells differentiate into spermatozoa. To better understand the molecular mechanisms of the process, the Cre/loxP system has been widely utilized for conditional gene knockout in mice. In this study, we generated a transgenic mouse line that expresses Cre recombinase under the control of the 2.5 kbp of the Prolactin family 3, subfamily b, member 1 (Prl3b1) gene promoter (Prl3b1-cre). Prl3b1 was initially reported to code for placental lactogen 2 (PL-2) protein in placenta along with increased expression toward the end of pregnancy. PL-2 was found to be expressed in germ cells in the testis, especially in spermatocytes. To analyze the specificity and efficiency of Cre recombinase activity in Prl3b1-cre mice, the mice were mated with reporter R26GRR mice, which express GFP ubiquitously before and tdsRed exclusively after Cre recombination. The systemic examination of Prl3b1-cre;R26GRR mice revealed that tdsRed-positive cells were detected only in the testis and epididymis. Fluorescence imaging of Prl3b1-cre;R26GRR testes suggested that Cre-mediated recombination took place in the germ cells with approximately 74% efficiency determined by in vitro fertilization. In conclusion, our results suggest that the Prl3b1-cre mice line provides a unique resource to understand testicular germ-cell development. genesis 54:389-397, 2016. © 2016 Wiley Periodicals, Inc.

Localizing PRL-2 expression and determining the effects of dietary Mg(2+) on expression levels.

The phosphatase of regenerating liver (PRL) is a group of protein tyrosine phosphatases that play a key role in cancer progression and metastasis. We previously showed that PRL-2 modulates intracellular Mg(2+) levels and sustains cancer phenotypes by binding to the Mg(2+) transporter CNNM3. However, the physiological functions of PRL-2 in animals remain largely unknown. To better understand which cell types are associated with PRL-2 function, we characterized its expression in mouse tissues using a PRL-2 ß-galactosidase reporter mouse model. Our results demonstrated that PRL-2 was ubiquitously expressed, with the highest expression levels observed in the hippocampal pyramidal neurons, ependymal cells, cone and rod photoreceptor cells, endocardium, vascular and bronchial smooth muscle, and collecting ducts in the kidney. On the other hand, PRL-2 expression was undetectable or very low in the parenchymal cells of the liver and pancreas. Our results also indicated that PRL-2 is involved in cell-type-specific Mg(2+) homeostasis and that PRL-2 expression is potentially inversely regulated by dietary Mg(2+) levels.

Overexpression of PTP4A3 is associated with metastasis and unfavorable prognosis in bladder cancer.

PURPOSE: Bladder cancer (BC) is the most common malignancy in urinary system. The prognosis of metastatic BC is poor, but there remains no reliable marker to early detect metastasis. Dysregulated prenylated protein tyrosine phosphatases (PTPs) are commonly associated with cancer metastasis. From a published BC transcriptome, we identified that PTP IVA3 (PTP4A3) was the most significantly upregulated gene implicated in tumor progression among genes related to prenylated PTPs. We therefore analyzed PTP4A3 expression in our well-characterized cohort of BC. METHODS: By immunohistochemistry, PTP4A3 expression was determined using H-score. PTP4A3 expression of 295 BCs was compared with clinicopathological parameters, and the effect of PTP4A3 on cancer-specific survival (CSS) and metastasis-free survival (MFS) was also examined. Two independent sets of BCs were used to assess PTP4A3 protein and transcript expression in normal urothelium and different stage tumors. RESULTS: PTP4A3 overexpression was significantly associated with higher pT stage (P < 0.001), nodal metastasis (P < 0.001), vascular invasion (P < 0.001), and perineural invasion (P = 0.021). In multivariate analysis, PTP4A3 overexpression was an independent predictor for CSS (P < 0.001) and MFS (P = 0.007). Notably, the difference in CSS and MFS between high and low PTP4A3-expressing tumors was also significant in muscle-invasive BCs. PTP4A3 protein expression showed significant and stepwise increments from normal urothelium to noninvasive BC, invasive BC, and metastatic foci (P < 0.001). PTP4A3 transcript was also obviously upregulated in high-stage BC (P < 0.001). CONCLUSIONS: PTP4A3 may play a role in BC oncogenesis and is a predictive marker of metastasis. PTP4A3 overexpression represents an independent prognosticator for BC, suggesting its potential theranostic value.

Overexpression of protein tyrosine phosphatase 1B impairs glucose-stimulated insulin secretion in INS-1 cells.

BACKGROUND: Protein tyrosine phosphatase 1B (PTP1B) has been implicated as a negative regulator of insulin signaling. We reported previously that impaired glucose-stimulated insulin secretion (GSIS) in rats fed high-fat diet was associated with higher PTP1B protein levels in islets. The aim of the present study was to investigate the effect of increasing PTP1B on insulin secretion in ß-cells. METHODS: INS-1 cells were transduced with recombinant adenoviruses containing human PTP1B cDNA (Ad-PTP1B), or no exogenous gene (Ad-ctrl). The expression levels of PTP1B, insulin receptor (IR), insulin receptor substrate-1(IRS-1), glucokinase and glucose transporter-2 were evaluated by Western blot. Then insulin-stimulated IR and IRS tyrosine phosphorylation, and Akt pathway activation were measured. GSIS was also performed to evaluate INS-1 cells function. RESULTS: PTP1B expression level was increased 5.9-fold at 48h post-transduction. The overexpression of PTP1B had no effect on proliferation and apoptosis of INS-1 cells. Compared with control cells, INS-1 cells overexpressing PTP1B showed decrease in insulin-stimulated tyrosine phosphorylation of the insulin receptor (IR) and insulin receptor substrate-1(IRS-1) by 56.4% and 53.1%, respectively. In addition, Akt phosphorylation was reduced 59.6%. Moreover, in Ad-PTP1B-transduced cells, 16.7mM glucose caused a 1.6±0.2 fold increase (vs. 3.9±0.7 fold in nontransduced cells) in insulin secretion relative to secretion at 2.8mM glucose. Further analysis determined that overexpression of PTP1B induced down-regulated expression of glucokinase (42%) and glucose transporter-2 (48%). CONCLUSIONS: Our findings suggested that overexpression of PTP1B can inhibit GSIS in INS-1 cells through negatively regulating insulin signaling.

Anti-miR-148a regulates platelet FcγRIIA signaling and decreases thrombosis in vivo in mice.

Fc receptor for IgG IIA (FcγRIIA)-mediated platelet activation is essential in heparin-induced thrombocytopenia (HIT) and other immune-mediated thrombocytopenia and thrombosis disorders. There is considerable interindividual variation in platelet FcγRIIA activation, the reasons for which remain unclear. We hypothesized that genetic variations between FcγRIIA hyper- and hyporesponders regulate FcγRIIA-mediated platelet reactivity and influence HIT susceptibility. Using unbiased genome-wide expression profiling, we observed that human hyporesponders to FcγRIIA activation showed higher platelet T-cell ubiquitin ligand-2 (TULA-2) mRNA expression than hyperresponders. Silent interfering RNA-mediated knockdown of TULA-2 resulted in hyperphosphorylation of spleen tyrosine kinase following FcγRIIA activation in HEL cells. Significantly, we found miR-148a-3p targeted and inhibited both human and mouse TULA-2 mRNA. Inhibition of miR-148a in FcγRIIA transgenic mice upregulated the TULA-2 level and reduced FcγRIIA- and glycoprotein VI-mediated platelet αIIbß3 activation and calcium mobilization. Anti-miR-148a also reduced thrombus formation following intravascular platelet activation via FcγRIIA. These results show that TULA-2 is a target of miR-148a-3p, and TULA-2 serves as a negative regulator of FcγRIIA-mediated platelet activation. This is also the first study to show the effects of in vivo miRNA inhibition on platelet reactivity. Our work suggests that modulating miR-148a expression is a potential therapeutic approach for thrombosis.

PTP4A3 Independently Predicts Metastasis and Survival in Upper Tract Urothelial Carcinoma Treated with Radical Nephroureterectomy.

PURPOSE: Increasing evidence has shown that protein tyrosine phosphatases have dominant roles in setting the levels of tyrosine phosphorylation and promoting oncogenic processes. PTP4A3 has been implicated in cancer metastasis but to our knowledge the role of PTP4A3 in upper tract urothelial carcinoma is unknown. The aim of this study was to investigate the association of PTP4A3 with disease characteristics, distant metastasis and prognosis of upper tract urothelial carcinoma. MATERIALS AND METHODS: The importance of PTP4A3 was initially examined in paired normal urothelium, noninvasive upper tract urothelial carcinoma, invasive upper tract urothelial carcinoma and nodal metastatic tissue. The PTP4A3 transcript level was assessed in another 20 upper tract urothelial carcinoma samples by real-time reverse transcriptase-polymerase chain reaction. PTP4A3 protein expression was determined by immunohistochemistry using the H-score in 340 upper tract urothelial carcinoma samples. It was further correlated with clinicopathological factors, and disease specific and metastasis-free survival. RESULTS: The expression of PTP4A3 significantly increased from normal urothelium, noninvasive upper tract urothelial carcinoma and invasive upper tract urothelial carcinoma to nodal metastatic tissue (p <0.001). The PTP4A3 transcript level was also markedly up-regulated in higher stage upper tract urothelial carcinoma (p = 0.002). Over expression of PTP4A3 protein was significantly associated with advanced pT status, nodal metastasis, lymphovascular invasion and perineural invasion (each p <0.001) as well as with inferior disease specific and metastasis-free survival on multivariate analysis (each p <0.0001). In addition, it predicted metastasis in patients with pTa, pT1 and pT2 upper tract urothelial carcinoma. CONCLUSIONS: Results imply that PTP4A3 has a role in the carcinogenesis of upper tract urothelial carcinoma. PTP4A3 over expression independently predicted the metastasis and outcome of upper tract urothelial carcinoma, which was even more important in organ confined disease.