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Prostate cancer (PCa) is threatening the health of millions of people, the pathological mechanism of prostate cancer has not been fully elaborated, and needs to be further explored. Here, we found that the expression of DUSP26 is dramatically suppressed, and a positive connection of its expression with PCa prognosis was also observed. In vitro, overexpression of DUSP26 significantly inhibited the proliferative, migrative, and invasive capacities of PC3 cells, DUSP26 silencing presented opposite results. Tumor formation experiments in subcutaneous nude mice demonstrated that DUSP26 overexpression could significantly suppress PC3 growth in vivo. Moreover, the mechanism of DUSP26 gene and PCa was discovered by RNA-Seq analysis. We found that DUSP26 significantly inhibited MAPK signaling pathway activation, and further experiments displayed that DUSP26 could impair TAK1, p38, and JNK phosphorylation. Interestingly, treatment with the TAK1 inhibitor (iTAK1) attenuated the effect of DUSP26 on PC3 cells. Together, these results suggested that DUSP26 may serve as a novel therapeutic target for PC3 cell type PCa, the underlying mechanism may be through TAK1-JNK/p38 signaling., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest cancers among all solid tumors. First-line treatment relies on gemcitabine (Gem) and despite treatment improvements, refractoriness remains a universal challenge. Attempts to decipher how feedback-loops control signaling pathways towards drug resistance have gained attention in recent years, particularly focused on the role of phosphatases. In this study, a CRISPR/Cas9-based phenotypic screen was performed to identify members from the dual-specificity phosphatases (DUSP) family potentially acting on Gem response in PDAC cells. The approach revealed the atypical RNA phosphatase DUSP11 as a potential target, whose inhibition creates vulnerability of PDAC cells to Gem. DUSP11 genetic inhibition impaired cell survival and promoted apoptosis, synergistically enhancing Gem cytotoxicity. In silico transcriptome analysis of RNA-seq data from PDAC human samples identified NF-ĸB signaling pathway highly correlated with DUSP11 upregulation. Consistently, Gem-induced NF-ĸB phosphorylation was blocked upon DUSP11 inhibition in vitro. Mechanistically, we found that DUSP11 directly impacts nc886 expression and modulates PKR-NF-ĸB signaling cascade after Gem exposure in PDAC cells resulting in resistance to Gem-induced cell death. In conclusion, this study provides new insights on DUSP11 role in RNA biology and Gem response in PDAC cells., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Obesity is a low-grade chronic inflammation induced by the pathological expansion of adipocytes which allows the development of obesity-associated metabolic diseases like type 2 diabetes mellitus (T2D) and non-alcoholic fatty liver disease (NAFLD). However, mechanisms regulating adipocyte inflammation remain poorly understood. Here, we observed that TRIM8 was upregulated in adipocyte inflammation and insulin resistance while DUSP14 was downregulated. TRIM8 deficiency and DUSP14 over-expression decreased the level of inflammatory cytokines, increased glucose uptake content, and improved insulin signalling transduction compared to LPS treatment alone. Conversely, silencing DUSP14 increased the expression of inflammatory cytokines. It decreased the glucose uptake content and the phosphorylation level of proteins involved in insulin signalling, further impairing insulin signalling and aggravating insulin resistance. Furthermore, The decreased level of inflammatory cytokines, increased glucose uptake, and improved insulin signalling transduction caused by TRIM8 deficiency were reversed by down-regulated DUSP14. Collectively, our findings revealed that TRIM8 can regulate adipocyte inflammation and insulin resistance by regulating the MAPKs pathway which is dependent on DUSP14.

Background: Exosomes play a crucial role in promoting tumor progression, dissemination, and resistance to treatment. These extracellular vesicles hold promise as valuable indicators for cancer detection. Our investigation focuses on exploring the significance and clinical relevance of exosomal miRNAs in small cell lung cancer (SCLC)., Methods: Serum exosomes were isolated from both SCLC patients and healthy controls, and subjected to exosomal miRNA sequencing analysis. Mimics and inhibitors were employed to investigate the function of exosomal miR-1128-5p in cell migration and proliferation, both in vitro and in vivo. Western blot and luciferase assay were utilized to identify the interaction between miR-1228-5p and dual specificity phosphatase 22 (DUSP22)., Results: Exosomal miRNA sequencing analysis revealed enrichment of specific miRNAs in SCLC compared to healthy controls. Circulating miR-1228-5p was upregulated in SCLC patients, associated with advanced stages, suggesting its potential oncogenic role. In vitro, miR-1228-5p expression was significantly higher in SCLC cells than in normal cells. SCLC cell-derived exosomes contained elevated levels of miR-1228-5p, facilitating its entry into co-cultured cells. Notably, migration and proliferation induced by SCLC exosomes were mainly mediated by miR-1228-5p. In vivo experiments confirmed these findings. Western blot analysis demonstrated miR-1228-5p's regulation of DUSP22 expression, and luciferase reporter assay validated DUSP22 as a direct target gene. Overexpressing DUSP22 counteracted miR-1228-5p's promotion of SCLC cell proliferation and migration., Conclusions: Collectively, our results suggest that exosomes play a role in facilitating cancer growth and metastasis by delivering miR-1228-5p. Moreover, circulating exosomal miR-1228-5p may serve as a potential marker for SCLC diagnosis and prognosis., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Previous studies have demonstrated that Dual-specificity phosphatase 4 (DUSP4) plays an important role in the progression of different tumor types. However, the role and mechanism of DUSP4 in colorectal cancer (CRC) remain unclear., Aims: We investigate the role and mechanisms of DUSP4 in CRC., Methods: Immunohistochemistry was used to investigate DUSP4 expression in CRC tissues. Cell proliferation, apoptosis and migration assays were used to validate DUSP4 function in vitro and in vivo. RNA-sequence assay was used to identify the target genes of DUSP4. Human phosphokinase array and inhibitor assays were used to explore the downstream signaling of DUSP4., Results: DUSP4 expression was upregulated in CRC tissues relative to normal colorectal tissues, and DUSP4 expression showed a significant positive correlation with CRC stage. Consistently, we found that DUSP4 was highly expressed in colorectal cancer cells compared to normal cells. DUSP4 knockdown inhibits CRC cell proliferation, migration and promotes apoptosis. Furthermore, the ectopic expression of DUSP4 enhanced CRC cell proliferation, migration and diminished apoptosis in vitro and in vivo. Human phosphokinase array data showed that ectopic expression of DUSP4 promotes CREB activation. RNA-sequencing data showed that PRKACB acts as a downstream target gene of DUSP4/CREB and enhances CREB activation through PKA/cAMP signaling. In addition, xenograft model results demonstrated that DUSP4 promotes colorectal tumor progression via PRKACB/CREB activation in vivo., Conclusion: These findings suggest that DUSP4 promotes CRC progression. Therefore, it may be a promising therapeutic target for CRC., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Colorectal cancer (CRC) is one of the most prevalent and life-threatening cancers. Rapid cell proliferation is the leading cause of cancer-related death in CRC. MicroRNAs (miRNAs) have been identified to play essential roles in the proliferation of CRC. Differential expression of let-7c-5p in CRC was assessed using a GEO dataset, and confirmed through RT-qPCR using CRC subject tissues. Let-7c-5p-overexpressing HCT8 cell line was constructed by transfecting let-7c-5p. Bioinformatics analysis identified that DUSP7 is the target gene of let-7c-5p. Further experimental assays, including Cell Counting Kit-8 (CCK8), EdU staining, cell colony, and Western Blot assays, confirmed the target genes and pathway of let-7c-5p. Receiver operator characteristic curve (ROC) analysis was performed to evaluate the diagnostic value of let-7c-5p for CRC. Finally, survival analysis was performed to determine the effect of DUSP7 and let-7c-5p on the prognosis of CRC patients. RT-qPCR analysis showed that the expression level of let-7c-5p was significantly increased in CRC subject tissues compared to the adjacent tissue. Overexpression of let-7c-5p promoted cell proliferation in HCT8 cell line. Furthermore, the MAPK-ERK pathway's protein expression of p-ERK1/2 was downregulated, while the ratio of Bcl-2/Bax was increased by let-7c-5p transfection in HCT 8. ROC analysis demonstrated that the expressive level of let-7c-5p had higher diagnostic value for CRC. Survival curve analysis indicated that high expression of DUSP7 and low expression of let-7c-5p were associated with poor prognosis in CRC patients. The findings suggest that let-7c-5p exerts an antitumor function by inhibiting the DUSP7-mediated MAPK-ERK pathway. Both DUSP7 and let-7c-5p have the potential to serve as prognostic biomarkers in CRC patients., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Tumor cells reprogram their metabolism to produce specialized metabolites that both fuel their own growth and license tumor immune evasion. However, the relationships between these functions remain poorly understood. Here, we report CRISPR screens in a mouse model of colo-rectal cancer (CRC) that implicates the dual specificity phosphatase 18 (DUSP18) in the establishment of tumor-directed immune evasion. Dusp18 inhibition reduces CRC growth rates, which correlate with high levels of CD8 + T cell activation. Mechanistically, DUSP18 dephosphorylates and stabilizes the USF1 bHLH-ZIP transcription factor. In turn, USF1 induces the SREBF2 gene, which allows cells to accumulate the cholesterol biosynthesis intermediate lanosterol and release it into the tumor microenvironment (TME). There, lanosterol uptake by CD8 + T cells suppresses the mevalonate pathway and reduces KRAS protein prenylation and function, which in turn inhibits their activation and establishes a molecular basis for tumor cell immune escape. Finally, the combination of an anti-PD-1 antibody and Lumacaftor, an FDA-approved small molecule inhibitor of DUSP18, inhibits CRC growth in mice and synergistically enhances anti-tumor immunity. Collectively, our findings support the idea that a combination of immune checkpoint and metabolic blockade represents a rationally-designed, mechanistically-based and potential therapy for CRC., (© 2024. The Author(s).)

Plants have evolved a sophisticated immunity system for specific detection of pathogens and rapid induction of measured defences. Over- or constitutive activation of defences would negatively affect plant growth and development. Hence, the plant immune system is under tight positive and negative regulation. MAP kinase phosphatase1 (MKP1) has been identified as a negative regulator of plant immunity in model plant Arabidopsis. However, the molecular mechanisms by which MKP1 regulates immune signalling in wheat (Triticum aestivum) are poorly understood. In this study, we investigated the role of TaMKP1 in wheat defence against two devastating fungal pathogens and determined its subcellular localization. We demonstrated that knock-down of TaMKP1 by CRISPR/Cas9 in wheat resulted in enhanced resistance to rust caused by Puccinia striiformis f. sp. tritici (Pst) and powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt), indicating that TaMKP1 negatively regulates disease resistance in wheat. Unexpectedly, while Tamkp1 mutant plants showed increased resistance to the two tested fungal pathogens they also had higher yield compared with wild-type control plants without infection. Our results suggested that TaMKP1 interacts directly with dephosphorylated and activated TaMPK3/4/6, and TaMPK4 interacts directly with TaPAL. Taken together, we demonstrated TaMKP1 exert negative modulating roles in the activation of TaMPK3/4/6, which are required for MAPK-mediated defence signalling. This facilitates our understanding of the important roles of MAP kinase phosphatases and MAPK cascades in plant immunity and production, and provides germplasm resources for breeding for high resistance and high yield., (© 2024 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)

Dual-specificity phosphatase 26 (DUSP26) acts as a pivotal player in the transduction of signalling cascades with its dephosphorylating activity. Currently, DUSP26 attracts extensive attention due to its particular function in several pathological conditions. However, whether DUSP26 plays a role in kidney ischaemia-reperfusion (IR) injury is unknown. Aims of the current work were to explore the relevance of DUSP26 in kidney IR damage. DUSP26 levels were found to be decreased in renal tubular epithelial cells following hypoxia-reoxygenation (HR) and kidney samples subjected to IR treatments. DUSP26-overexpressed renal tubular epithelial cells exhibited protection against HR-caused apoptosis and inflammation, while DUSP26-depleted renal tubular epithelial cells were more sensitive to HR damage. Upregulation of DUSP26 in rat kidneys by infecting adenovirus expressing DUSP26 markedly ameliorated kidney injury caused by IR, while also effectively reducing apoptosis and inflammation. The mechanistic studies showed that the activation of transforming growth factor-β-activated kinase 1 (TAK1)-JNK/p38 MAPK, contributing to kidney injury under HR or IR conditions, was restrained by increasing DUSP26 expression. Pharmacological restraint of TAK1 markedly diminished DUSP26-depletion-exacebated effects on JNK/p38 activation and HR injury of renal tubular cells. The work reported a renal-protective function of DUSP26, which protects against IR-related kidney damage via the intervention effects on the TAK1-JNK/p38 axis. The findings laid a foundation for understanding the molecular pathogenesis of kidney IR injury and provide a prospective target for treating this condition., Competing Interests: Declaration of competing interest The authors declare that no conflict of interest exists in this work., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Aims: This investigation aims to elucidate the mechanism underlying sorafenib-induced ferroptosis in hepatocellular carcinoma (HCC)., Methods: The role of dual specificity phosphatase 4 (DUSP4) in sorafenib-treated HCC was investigated using comprehensive assessments both in vitro and in vivo, including Western blotting, qRT-PCR, cell viability assay, lipid reactive oxygen species (ROS) assay, immunohistochemistry, and xenograft tumor mouse model. Additionally, label-free quantitative proteomics was employed to identify potential proteins associated with DUSP4., Results: Our study revealed that suppression of DUSP4 expression heightens the susceptibility of HCC cells to ferroptosis inducers, specifically sorafenib and erastin, in both in vitro and in vivo settings. Furthermore, we identified DUSP4-mediated regulation of key ferroptosis-related markers, such as ferritin light chain (FTL) and ferritin heavy chain 1 (FTH1). Notably, label-free quantitative proteomics unveiled the phosphorylation of threonine residue T148 on YTH Domain Containing 1 (YTHDC1) by DUSP4. Further investigations unraveled that YTHDC1, functioning as an mRNA nuclear export regulator, is a direct target of DUSP4, orchestrating the subcellular localization of FTL and FTH1 mRNAs. Significantly, our study highlights a strong correlation between elevated DUSP4 expression and sorafenib resistance in HCC., Conclusions: Our findings introduce DUSP4 as a negative regulator of sorafenib-induced ferroptosis. This discovery opens new avenues for the development of ferroptosis-based therapeutic strategies tailored for HCC treatment., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Protein kinase B (AKT) plays a pivotal in regulating cell migration, proliferation, apoptosis, and survival, making it a prominent target for anticancer therapy. While the kinase activity of AKT has been extensively explored, its dephosphorylation have largely remained uncharted. Herein, we aimed to unravel the molecular mechanisms governing AKT dephosphorylation, with a specific emphasis on dual-specificity phosphatases DUSP22. Our investigation sought to shed light on the potential of DUSP22 as a potential therapeutic target for non-small cell lung cancer (NSCLC). To determine the expression level of DUSP22 in NSCLC cell lines, the gene expression profiling interactive analysis (GEPIA) and Oncomine database were searched. Additionally, the effect of DUSP22 on patient survival was analyzed with Kaplan-Meier database. Antitumor effects of DUSP22 were tested in A549 and H1299 cell lines. Experiments are based on: (1) cell viability determined by the cell counting kit-8 assay and colony-formation assay; (2) cell migratory ability assessed through the scratch assay and the transwell migration assay; (3) the mechanism behind the antitumor effects of DUSP22 dissected with co-immunoprecipitation (Co-IP) and in vitro kinase assays. Our study revealed a significant downregulation of DUSP22 in both NSCLC cell lines and tissues. Meanwhile, survival rate analysis results demonstrated that reduced DUSP22 expression was correlated with poorer overall survival in lung cancer patients. Moreover, DUSP22 exhibited an inhibitory effect on the cell viability and migratory capacity of A549 and H1299 cells. This inhibition was accompanied by the decrease in the phosphorylation of AKT and p38. Mechanistically, the phosphatase domain of DUSP22 interacted with AKT, resulting in the inhibition of AKT phosphorylation. This inhibitory effect was contingent upon the phosphatase activity of DUSP22. These findings provide compelling evidence that DUSP22 directly interacted with AKT, leading to the dephosphorylation of AKT at S473 and T308 residues, ultimately curbing the proliferation and migration of lung cancer cells. Additionally, our results also highlight a preclinical rationale for utilizing DUSP22 as a prognostic marker in NSCLC., (© 2023 Wiley Periodicals LLC.)

Studies indicate that mitogen-activated protein kinases (MAPKs) are activated and overexpressed in psoriatic lesions. The aim of the study was to assess changes in the expression pattern of genes encoding MAPKs and microRNA (miRNA) molecules potentially regulating their expression in human adult low-calcium high-temperature (HaCaT) keratinocytes exposed to bacterial lipopolysaccharide A (LPS) and cyclosporine A (CsA). HaCaT cells were treated with 1 µg/mL LPS for 8 h, followed by treatment with 100 ng/mL cyclosporine A for 2, 8, or 24 h. Untreated cells served as controls. The molecular analysis consists of microarray, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay analyses. The statistical analysis of the obtained results was performed using Transcriptome Analysis Console and STATISTICA 13.5 PL with the statistical significance threshold of p  < 0.05. Changes in the expression profile of six mRNAs: dual-specificity phosphatase 1 ( DUSP1) , dual-specificity phosphatase 4 ( DUSP4) , mitogen-activated protein kinase kinase 2 ( MAP2K2) , mitogen-activated protein kinase kinase 7 ( MAP2K7) , mitogen-activated protein kinase kinase kinase 2 ( MAP3K2) and mitogen-activated protein kinase 9 ( MAPK9) in cell culture exposed to LPS or LPS and the drug compared to the control. We observed that under the LPS and cyclosporine treatment, the expression o/ miR-34a, miR-1275, miR-3188, and miR-382 changed significantly ( p  < 0.05). We demonstrated a potential relationship between DUSP1 and miR-34a; DUSP4 and miR-34a, miR-382, and miR-3188; MAPK9 and miR-1275, MAP2K7 and mir-200-5p; MAP3K2 and mir-200-5p, which may be the subject of further research in the context of psoriasis.

Background: It is well established that females are more susceptible to the toxic effects of alcohol, although the exact mechanisms are still poorly understood. Previous studies noted that alcohol reduces the expression of mitogen-activated protein kinase phosphatase 1 (MKP1), a negative regulator of mitogen-activated protein kinases (MAPK) in the liver. However, the role of hepatocyte- specific MKP1 in the pathogenesis of alcohol-associated liver disease (ALD) remains uncharacterized. This study aimed to evaluate the role of hepatocyte-specific MKP1 in the susceptibility and sexual dimorphism in alcohol-induced liver injury., Methods: C57Bl/6 mice were used in an intragastric ethanol feeding model of alcohol-associated steatohepatitis (ASH). Hepatocyte-specific Mkp1 -/- knockout and ( Mkp1 +/+ "f/f" male and female mice were subjected to the NIAAA chronic plus binge model. Primary mouse hepatocytes were used for in vitro studies. Liver RNA sequencing was performed on an Illumina NextSeq 500. Liver injury was evaluated by plasma alanine transaminase (ALT), hepatic ER stress and inflammation markers. Statistical analysis was carried out using ANOVA and the unpaired Student's t-test., Results: ASH was associated with the severe injury accompanied by increased endoplasmic reticulum (ER) stress and significant downregulation of Dusp1 mRNA expression. In vitro , ethanol treatment resulted in a time-dependent decrease in Dusp1 mRNA and protein expression in primary hepatocytes in both males and females; however, this effect was significantly more pronounced in hepatocytes from females. In vivo , female mice developed more liver injury in a chronic plus binge model which was accompanied by a significant decrease in liver Dusp1 mRNA expression. In comparison, liver Dusp1 was not changed in male mice, while they developed milder injury to alcohol. Mkp1 deletion in hepatocytes led to increased alcohol induced liver injury, ER stress and inflammation in both sexes., Conclusion: Hepatocyte Mkp1 plays a significant role in alcohol induced liver injury. Alcohol downregulates Mkp1 expression in hepatocytes in a sex dependent manner and could play a role in sexual dimorphism in increased female susceptibility to alcohol., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Walter, Montoya-Durango, Rodriguez, Wang, Zhang, Chariker, Rouchka, Maldonado, Bennett, McClain, Barve and Gobejishvili.)

DUSP22 is a dual-specificity phosphatase that inhibits T cell activation by inactivating the kinase Lck. Here we show that the E3 ubiquitin ligase UBR2 is a positive upstream regulator of Lck during T-cell activation. DUSP22 dephosphorylates UBR2 at specific Serine residues, leading to ubiquitin-mediated UBR2 degradation. UBR2 is also modified by the SCF E3 ubiquitin ligase complex via Lys48-linked ubiquitination at multiple Lysine residues. Single-cell RNA sequencing analysis and UBR2 loss of function experiments showed that UBR2 is a positive regulator of proinflammatory cytokine expression. Mechanistically, UBR2 induces Lys63-linked ubiquitination of Lck at Lys99 and Lys276 residues, followed by Lck Tyr394 phosphorylation and activation as part of TCR signalling. Inflammatory phenotypes induced by TCR-triggered Lck activation or knocking out DUSP22, are attenuated by genomic deletion of UBR2. UBR2-Lck interaction and Lck Lys63-linked ubiquitination are induced in the peripheral blood T cells of human SLE patients, which demonstrate the relevance of the UBR2-mediated regulation of inflammation to human pathology. In summary, we show here an important regulatory mechanism of T cell activation, which finetunes the balance between T cell response and aggravated inflammation., (© 2024. The Author(s).)

Background: ARID1A, a tumor suppressor gene encoding BAF250, a protein participating in chromatin remodeling, is frequently mutated in endometrium-related malignancies, including ovarian or uterine clear cell carcinoma (CCC) and endometrioid carcinoma (EMCA). However, how ARID1A mutations alter downstream signaling to promote tumor development is yet to be established., Methods: We used RNA-sequencing (RNA-seq) to explore transcriptomic changes in isogenic human endometrial epithelial cells after deleting ARID1A. Chromatin immunoprecipitation sequencing (ChIP-seq) was employed to assess the active or repressive histone marks on DUSP4 promoter and regulatory regions. We validated our findings using genetically engineered murine endometroid carcinoma models, human endometroid carcinoma tissues, and in silico approaches., Results: RNA-seq revealed the downregulation of the MAPK phosphatase dual-specificity phosphatase 4 (DUSP4) in ARID1A-deficient cells. ChIP-seq demonstrated decreased histone acetylation marks (H3K27Ac, H3K9Ac) on DUSP4 regulatory regions as one of the causes for DUSP4 downregulation in ARID1A-deficient cells. Ectopic DUSP4 expression decreased cell proliferation, and pharmacologically inhibiting the MAPK pathway significantly mitigated tumor formation in vivo., Conclusions: Our findings suggest that ARID1A protein transcriptionally modulates DUSP4 expression by remodeling chromatin, subsequently inactivating the MAPK pathway, leading to tumor suppression. The ARID1A-DUSP4-MAPK axis may be further considered for developing targeted therapies against ARID1A-mutated cancers., (© 2023. The Author(s).)

The onset of obstetric antiphospholipid syndrome (APS) occurs when antiphospholipid antibodies act upon the placenta. During pregnancy, APS exhibits traits such as vascular thrombosis, inflammation, and hindered trophoblast implantation. The involvement of microRNA expression has been proposed as a genetic factor contributing to the syndrome's development. MicroRNAs play a role in regulating gene expression in various cellular processes, including the formation of placental tissue. Therefore, additional research is needed to explore the control of placental miRNA in APS. In this study, we aimed to profile miRNA expressions from placenta tissue of patients with APS. Differentially expressed miRNAs were determined for its targeted genes and pathways. Agilent microarray platform was used to measure placental microRNA expressions between normal placental tissue and those obtained from patients with APS. Differentially expressed miRNAs were detected using GeneSpring GX software 14.2 and sequences were mapped using TargetScan software to generate the predicted target genes. Pathway analysis for the genes was then performed on PANTHER and REACTOME software. Selected miRNAs and their associated genes of interest were validated using qPCR. Microarray findings revealed, 9 downregulated and 21 upregulated miRNAs expressed in placenta of patients with APS. Quantitative expressions of 3 selected miRNAs were in agreement with the microarray findings, however only miR-525-5p expression was statistically significant. Pathway analysis revealed that the targeted genes of differentially expressed miRNAs were involved in several hypothesised signalling pathways such as the vascular endothelial (VE) growth factor (VEGF) and inflammatory pathways. VE-cadherin, ras homolog member A (RHOA) and tyrosine kinase receptor (KIT) showed significant downregulation while Retinoblastoma gene (RET), Dual specificity protein phosphatase 10 (DUSP10) and B-lymphocyte kinase (BLK) genes were significantly upregulated. These preliminary findings suggest the involvement of miRNAs and identified novel associated genes involvement in the mechanism of obstetric APS, particularly through the alteration of vascular-associated regulators and the inflammatory signalling cascade.

Abnormal trophoblast function is associated with diseases such as recurrent spontaneous abortion, pre-eclampsia, and preterm birth, and endangers maternal and fetal health. However, the underlying regulatory mechanisms remain unclear. In this study, we found DOCK1 expression is decreased in the placental villi of patients with recurrent spontaneous abortion, and that its expression determined the invasive properties of extravillous trophoblasts (EVTs), highlighting a previously unknown role of DOCK1 in regulating EVT function. Furthermore, DOCK1 deficiency disturbed the ubiquitinated degradation of DUSP4, leading to its accumulation. This caused inactivation of the ERK signaling pathway, resulting in inadequate EVT migration and invasion. DOCK1 was implicated in regulating the ubiquitin levels of DUSP4, possibly by modulating the E3 ligase enzyme HUWE1. The results of our in vivo experiments confirmed that the DOCK1 inhibitor TBOPP caused miscarriage in mice by inactivating the DUSP4/ERK pathway. Collectively, our results revealed the crucial role of DOCK1 in the regulation of EVT function via the DUSP4-ERK pathway and a basis for the development of novel treatments for adverse pregnancy outcomes caused by trophoblast dysfunction., (© 2023 Xu et al.)

Drug-induced liver injury (DILI) is a widespread and harmful disease, and is closely linked to acute endoplasmic reticulum (ER) stress. Previous reports have shown that acute ER stress can suppress hepatic gluconeogenesis and even leads to hypoglycemia. However, the mechanism is still unclear. MAPK phosphatase 3 (MKP-3) is a positive regulator for gluconeogenesis. Thus, this study was conducted to investigate the role of MKP-3 in the suppression of gluconeogenesis by acute ER stress, as well as the regulatory role of acute ER stress on the expression of MKP-3. Results showed that acute ER stress induced by tunicamycin significantly suppressed gluconeogenesis in both hepatocytes and mouse liver, reduced glucose production level in hepatocytes, and decreased fasting blood glucose level in mice. Additionally, the protein level of MKP-3 was reduced by acute ER stress in both hepatocytes and mouse liver. Mkp-3 deficiency eliminated the inhibitory effect of acute ER stress on gluconeogenesis in hepatocytes. Moreover, the reduction effect of acute ER stress on blood glucose level and hepatic glucose 6-phosphatase ( G6pc ) expression was not observed in the liver-specific Mkp-3 knockout mice. Furthermore, activation of protein kinase R-like ER kinase (PERK) decreased the MKP-3 protein level, while inactivation of PERK abolished the reduction effect of acute ER stress on the MKP-3 protein level in hepatocytes. Taken together, our study suggested that acute ER stress could suppress hepatic gluconeogenesis by stimulating MKP-3 degradation via PERK, at least partially. Thus, MKP-3 might be a therapeutic target for DILI-related hypoglycemia.

Introduction: The unfolded protein response (UPR) has emerged as an important signaling pathway mediating anti-viral defenses to Respiratory Syncytial Virus (RSV) infection. Earlier we found that RSV replication predominantly activates the evolutionarily conserved Inositol Requiring Enzyme 1α (IRE1α)-X-Box Binding Protein 1 spliced (XBP1s) arm of the Unfolded Protein Response (UPR) producing inflammation, metabolic adaptation and cellular plasticity, yet the mechanisms how the UPR potentiates inflammation are not well understood., Methods: To understand this process better, we examined the genomic response integrating RNA-seq and Cleavage Under Targets and Release Using Nuclease (CUT&RUN) analyses. These data were integrated with an RNA-seq analysis conducted on RSV-infected small airway cells ± an IRE1α RNAse inhibitor., Results: We identified RSV induced expression changes in ~3.2K genes; of these, 279 required IRE1α and were enriched in IL-10/cytokine signaling pathways. From this data set, we identify those genes directly under XBP1s control by CUT&RUN. Although XBP1s binds to ~4.2 K high-confidence genomic binding sites, surprisingly only a small subset of IL10/cytokine signaling genes are directly bound. We further apply CUT&RUN to find that RSV infection enhances XBP1s loading on 786 genomic sites enriched in AP1/Fra-1, RELA and SP1 binding sites. These control a subset of cytokine regulatory factor genes including IFN response factor 1 (IRF1), CSF2, NFKB1A and DUSP10. Focusing on the downstream role of IRF1, selective knockdown (KD) and overexpression experiments demonstrate IRF1 induction controls type I and -III interferon (IFN) and IFN-stimulated gene (ISG) expression, demonstrating that ISG are indirectly regulated by XBP1 through IRF1 transactivation. Examining the mechanism of IRF1 activation, we observe that XBP1s directly binds a 5' enhancer sequence whose XBP1s loading is increased by RSV. The functional requirement for the enhancer is demonstrated by targeting a dCas9-KRAB silencer, reducing IRF1 activation. Chromatin immunoprecipitation shows that XBP1 is required, but not sufficient, for RSV-induced recruitment of activated phospho-Ser2 Pol II to the enhancer., Discussion: We conclude that XBP1s is a direct activator of a core subset of IFN and cytokine regulatory genes in response to RSV. Of these IRF1 is upstream of the type III IFN and ISG response. We find that RSV modulates the XBP1s binding complex on the IRF1 5' enhancer whose activation is required for IRF1 expression. These findings provide novel insight into how the IRE1α-XBP1s pathway potentiates airway mucosal anti-viral responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Qiao, Xu, Zhang, Yang and Brasier.)

Background: The study aims to profile the dual-specificity phosphatases (DUSP) expression in response to Transforming growth factor β1 (TGFβ1)-induced epithelial- mesenchymal transition (EMT) in ovarian adenocarcinoma cells., Methods: The ovarian adenocarcinoma cell line SKOV3 was used as a TGFβ1-induced EMT model. Cells were incubated with 5 ng/mL TGFβ1 to induce EMT. EMT was confirmed with real-time qPCR, western blot, and immunofluorescence analyses of various EMT markers. Western blot was used to analyze phospho- and total MAPK protein levels. Typical and atypical DUSPs mRNA expression profile was determined by real-time qPCR., Results: The epithelial marker E-cadherin expressions were decreased and mesenchymal EMT markers Snail and Slug expression levelswere increased after TGFβ1 induction. Phosphorylation of ERK1/2 and p38 MAPK were enhanced in response to TGFβ1 treatment. The expression of DUSP2, DUSP6, DUSP8, DUSP10, and DUSP13 were decreased while DUSP7, DUSP16, DUSP18, DUSP21, and DUSP27 were increased by TGFβ1., Discussion: TGFβ1 induced EMT which was accompanied by increased activity of MAPKs, and led to marked changes in expressions of several DUSPs in SKOV3 cells.

The molecular and pathogenic mechanisms of esophageal squamous cell carcinoma (ESCC) development are still unclear, which hinders the development of effective treatments. In this study, we report that DUSP4 is highly expressed in human ESCC and is negatively correlated with patient prognosis. Knockdown of DUSP4 suppresses cell proliferation and patient-derived xenograft (PDX)-derived organoid (PDXO) growth and inhibits cell-derived xenograft (CDX) development. Mechanistically, DUSP4 directly binds to heat shock protein isoform β (HSP90β) and promotes the ATPase activity of HSP90β by dephosphorylating HSP90β on T214 and Y216. These dephosphorylation sites are critical for the stability of JAK1/2-STAT3 signaling and p-STAT3 (Y705) nucleus translocation. In vivo, Dusp4 knockout in mice significantly inhibits 4-nitrochinoline-oxide-induced esophageal tumorigenesis. Moreover, DUSP4 lentivirus or treatment with HSP90β inhibitor (NVP-BEP800) significantly impedes PDX tumor growth and inactivates the JAK1/2-STAT3 signaling pathway. These data provide insight into the role of the DUSP4-HSP90β-JAK1/2-STAT3 axis in ESCC progression and describe a strategy for ESCC treatment., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023. Published by Elsevier Inc.)

Background: According to the World Health Organization Report, depressive disorders affect about 10% of the population. The molecular mechanism of the pathogenesis of depression is still not well understood. The new findings point to phosphatases as potential targets for effective depression therapy. The aim of the present work was the development of a method that would enable the identification of mitogen-activated protein kinase phosphatase-1 (MKP-1) protein partners using a proteomic approach., Methods: The research was carried out using the PC12 cell line, often used as a model for neurobiological research. The use of the procedure for efficient purification of protein complexes-tandem affinity purification (TAP) will facilitate the identification of proteins interacting with MKP-1, a potential goal of effective antidepressant therapy., Results: Identified proteins belong to various groups: cytoskeletal, ribosomal, nucleic acid binding, chaperones, and enzymes and may potentially be involved in the molecular mechanism of depression., Conclusions: The presented protocol for the purification of protein complexes is universal and can be successfully used in different mammalian cell lines. Proteins identified in the present work have been reported in the literature concerning studies on depressive disorders, which speaks in favour of their role in depression., (© 2023. The Author(s).)

Purpose: Dual-specificity phosphatase 4 (DUSP4) inactivates factors in the mitogen-activated protein kinase (MAPK) signaling cascade, activated in uveal melanoma (UM) by mutations in upstream G-protein α subunits GNAQ/11 in >90% cases. This study examined whether DUSP4 (1) protein expression in primary UM (pUM) was a biomarker of metastatic risk and (2) knockdown sensitized UM cells to therapeutic agents, selumetinib or doxorubicin., Methods: DUSP4 mRNA data from The Cancer Genome Atlas and DUSP4 protein expression examined using immunohistochemistry in 28 cases of pUM were evaluated for association with clinical, genetic, and histological features. In vitro cytotoxic drug assays tested the efficacy of selumetinib and doxorubicin in UM cell lines with/without small interfering RNA DUSP4 gene silencing., Results: DUSP4 protein expression was observed in 93% of cases, with strong nuclear positivity in 79%. Despite higher DUSP4 messenger RNA levels in disomy 3/wild-type BAP1 UM, there was no significant association of nDUSP4 protein with these metastatic risk predictors or outcome. DUSP4 expression in UM cell lines varied. DUSP4 silencing in Mel202, MP46, and MP41 cells did not affect ERK1/2 or phospho-ERK levels. Despite increased phospho-ERK levels in Mel285, no cell line showed enhanced sensitivity to selumetinib/doxorubicin., Conclusions: DUSP4 protein expression is not a biomarker of UM metastatic risk. DUSP4 plays a complex role in oncogenesis, as reported in other cancers, and further work is required to fully understand its functional role in the MAPK pathway., Translational Relevance: Understanding the role of phosphatases, such as DUSP4, in the control of intracellular signaling cascades will facilitate our ability to identify successful treatment options.

The dual-specificity phosphatases responsible for the inactivation of the mitogen-activated protein kinases (MAPKs) are designated as the MAPK phosphatases (MKPs). We demonstrated previously that MKP5 is regulated through a novel allosteric site suggesting additional regulatory mechanisms of catalysis exist amongst the MKPs. Here, we sought to determine whether the equivalent site within the phosphatase domain of a highly similar MKP family member, MKP7, is also important for phosphatase function. We found that mutation of tyrosine 271 (Y271) in MKP7, which represents the comparable Y435 within the MKP5 allosteric pocket, inhibited MKP7 catalytic activity. Consistent with this, when MKP7 Y271 mutants were overexpressed in cells, the substrates of MKP7, p38 MAPK or JNK, failed to undergo dephosphorylation. The binding efficiency of MKP7 to p38 MAPK and JNK1/2 was also reduced when MKP7 Y271 is mutated. Consistent with reduced MAPK binding, we observed a greater accumulation of nuclear p38 MAPK and JNK when the MKP7 Y271 mutants are expressed in cells as compared with WT MKP7, which sequesters p38 MAPK/JNK in the cytoplasm. Therefore, we propose that Y271 is critical for effective MAPK dephosphorylation through a mechanism whereby binding to this residue precedes engagement of the catalytic site and upon overexpression, MKP7 allosteric site mutants potentiate MAPK signaling. These results provide insight into the regulatory mechanisms of MKP7 catalysis and interactions with the MAPKs. Furthermore, these data support the generality of the MKP allosteric site and provide a basis for small molecule targeting of MKP7., Competing Interests: Conflict of interest The authors declare that they have no competing interests with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Nonalcoholic steatohepatitis (NASH), a common clinical disease, is becoming a leading cause of hepatocellular carcinoma (HCC). Dual specificity phosphatase 22 (DUSP22, also known as JKAP or JSP-1) expressed in numerous tissues plays essential biological functions in immune responses and tumor growth. However, the effects of DUSP22 on NASH still remain unknown. Here, we find a significant decrease of DUSP22 expression in human and murine fatty liver, which is mediated by reactive oxygen species (ROS) generation. Hepatic-specific DUSP22 deletion particularly exacerbates lipid deposition, inflammatory response and fibrosis in liver, facilitating NASH and non-alcoholic fatty liver disease (NAFLD)-associated HCC progression. In contrast, transgenic over-expression, lentivirus or adeno-associated virus (AAV)-mediated DUSP22 gene therapy substantially inhibit NASH-related phenotypes and HCC development in mice. We provide mechanistic evidence that DUSP22 directly interacts with focal adhesion kinase (FAK) and restrains its phosphorylation at Tyr397 (Y397) and Y576 + Y577 residues, subsequently prohibiting downstream activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) cascades. The binding of DUSP22 to FAK and the dephosphorylation of FAK are indispensable for DUSP22-meliorated NASH progression. Collectively, our findings identify DUSP22 as a key suppressor of NASH-HCC, and underscore the DUSP22-FAK axis as a promising therapeutic target for treatment of the disease., (© 2022. The Author(s).)

Pantothenate (Pan) is an essential nutrient required by both the mosquito vector and malaria parasite. We previously demonstrated that increasing pantothenate kinase (PanK) activity and co-enzyme A (CoA) biosynthesis led to significantly decreased parasite infection prevalence and intensity in the malaria mosquito Anopheles stephensi. In this study, we demonstrate that Pan stores in A. stephensi are a limited resource and that manipulation of PanK levels or activity, via small molecule modulators of PanK or transgenic mosquitoes, leads to the conversion of Pan to CoA and an overall reduction in Pan levels with minimal to no effects on mosquito fitness. Transgenic A. stephensi lines with repressed insulin signaling due to PTEN overexpression or repressed c-Jun N-terminal kinase (JNK) signaling due to MAPK phosphatase 4 (MKP4) overexpression exhibited enhanced PanK levels and significant reductions in Pan relative to non-transgenic controls, with the PTEN line also exhibiting significantly increased CoA levels. Provisioning of the PTEN line with the small molecule PanK modulator PZ-2891 increased CoA levels while provisioning Compound 7 decreased CoA levels, affirming chemical manipulation of mosquito PanK. We assessed effects of these small molecules on A. stephensi lifespan, reproduction and metabolism under optimized laboratory conditions. PZ-2891 and Compound 7 had no impact on A. stephensi survival when delivered via bloodmeal throughout mosquito lifespan. Further, PZ-2891 provisioning had no impact on egg production over the first two reproductive cycles. Finally, PanK manipulation with small molecules was associated with minimal impacts on nutritional stores in A. stephensi mosquitoes under optimized rearing conditions. Together with our previous data demonstrating that PanK activation was associated with significantly increased A. stephensi resistance to Plasmodium falciparum infection, the studies herein demonstrate a lack of fitness costs of mosquito Pan depletion as a basis for a feasible, novel strategy to control parasite infection of anopheline mosquitoes., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Doxorubicin (Dox) has limited efficiency in breast cancer (BC) due to drug-acquired resistance. The epithelial-mesenchymal transition (EMT) plays a major role in the survival and drug resistance of cancer cells. It was suggested that the JNK pathway was implicated in the response to Dox by regulating EMT. DUSP4/or MKP-2 is a well-known regulator of the JNK pathway and was found to be highly expressed in BC. However, its functional significance is not yet fully understood. In the present study, the possible involvement of MKP-2 in Dox-induced EMT was investigated in breast cancer cells. Immunohistochemistry for tissues obtained from BC patients ( n = 108) revealed 71.3% of tissues stained positively for MKP-2 while only 28.7% stained negatively. However, MKP-2 protein expression exhibited no significant relationship between BC prognostic factors, such as histological grade, histological type, hormonal status, and Ki-67 marker, its expression was significantly correlated with age 40 or below. In MDA-MB-231 cells, Dox-induced phosphorylation of JNK was sufficiently enhanced in MKP-2 silenced cells. This resulted in the attenuation of Dox-induced EMT, cell cycle arrest, and ultimately accelerated apoptosis. It was confirmed that the acquisition of Dox sensitivity by MKP-2 silencing largely depends on the stimulation of the JNK pathway. Indeed, results showed that overexpressing MKP-2 in non-tumorigenic MCF-12A cells dramatically inhibited Dox-induced JNK activation and, subsequently, cell death. The present study, to our knowledge, is the first to provide evidence for the potential role of MKP-2 in chemoresistance to Dox through modulating the JNK pathway and enhancing EMT.

A subset of dual-specificity phosphatases is a major negative regulator of MAPKs, and their involvement in tumorigenesis remains controversial. Among them, DUSP4 is reported to preferentially dephosphorylate extracellular signal‒regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase over p38. In this study, we aimed to identify a possible role of DUSP4 in melanoma genesis. An examination of large-scale public data on gene expression and dependency revealed a considerably high DUSP4 expression and dependency of the melanoma cell lines compared with those of other tumor cell lines, which was not apparent for the other 24 dual-specificity phosphatases genes encoded in the human genome. Using two melanoma lines, we confirmed that DUSP4 depletion impaired cell growth without notably inducing apoptosis. Interestingly, immunoblotting and kinase translocation reporter data revealed that DUSP4 depletion induces a decrease in ERK1/2 phosphorylation but barely affects c-Jun N-terminal kinase phosphorylation, suggesting that neither ERK nor c-Jun N-terminal kinase is a direct target of DUSP4 in our experimental setting. Notably, DUSP4 depletion led to an increase in DUSP6 level, possibly through a post-transcriptional process, and DUSP6 knockout almost eliminated the DUSP4-depletion effect on cell growth and ERK activity. Our findings suggest that DUSP4 plays a role in maintaining a high ERK1/2 activity by negatively regulating DUSP6 and thus contributes to the survival and growth of melanoma cells., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Aim: Deregulated signaling pathways are a hallmark feature of oncogenesis and driver of tumor progression. Dual specificity protein phosphatase 4 (DUSP4) is a critical negative regulator of the mitogen-activated protein kinase (MAPK) pathway and is often deleted or epigenetically silenced in tumors. DUSP4 alterations lead to hyperactivation of MAPK signaling in many cancers, including breast cancer, which often harbor mutations in cell cycle checkpoint genes, particularly in TP53., Methods: Using a genetically engineered mouse model, we generated mammary-specific Dusp4-deleted primary epithelial cells to investigate the necessary conditions in which DUSP4 loss may drive breast cancer oncogenesis., Results: We found that Dusp4 loss alone is insufficient in mediating tumorigenesis, but alternatively converges with loss in Trp53 and MYC amplification to induce tumorigenesis primarily through chromosome 5 amplification, which specifically upregulates Dbf4, a cell cycle gene that promotes cellular replication by mediating cell cycle checkpoint escape., Conclusions: This study identifies a novel mechanism for breast tumorigenesis implicating Dusp4 loss and p53 mutations in cellular acquisition of Dbf4 upregulation as a driver of cellular replication and cell cycle checkpoint escape., (© 2022. The Author(s).)

Non-small-cell lung cancer (NSCLC) is one of the most commonly diagnosed cancers worldwide with limited effective therapies. Cisplatin (DDP), as the first-line treatment, is always served as a mainstay of chemotherapeutic agents in combination with other drugs for NSCLC treatment. Nevertheless, DDP-based therapy is limited due to the frequent development of chemoresistance and adverse effects. Herein, it is necessary to find a more effective therapeutic approach with less toxicity. Falnidamol (FLD) is a pyrimido-pyrimidine compound and exerts anti-cancer activity. In the present study, we found that FLD could strongly promote the cytotoxicity of DDP and markedly reduce the IC 50 values to restrain the proliferation of NSCLC cells. Furthermore, combination of FLD and DDP remarkably induced G2/M cell cycle arrest, DNA damage and mitochondrial apoptosis, which was largely through the induction of reactive oxygen species (ROS). Additionally, FLD/DDP in combination greatly triggered ferroptosis, along with free iron accumulation and enhanced lipid peroxidation. Epithelial to mesenchymal transition (EMT) and epidermal growth factor receptor (EGFR) phosphorylation were also considerably restrained in NSCLC cells co-treated with FLD/DDP. Mechanistically, the combinative treatment significantly reduced DUSP26 expression in NSCLC cells. More studies showed that DUSP26 was strongly up-regulated in human NSCLC samples compared with the paired normal tissues, and high DUSP26 predicted poor overall survival rate among patients. Importantly, we found that DUSP26 suppression intensively reduced the proliferation, EMT process and pEGFR expression in NSCLC cells, whereas facilitated ROS production, DNA damage and cell death; however, opposite phenotype was observed in NSCLC cells over-expressing DUSP26. More importantly, DUSP26 over-expression completely abolished the anti-cancer function of FLD/DDP in NSCLC cells. Animal studies finally confirmed that FLD/DDP in combination efficiently reduced tumor growth and lung metastasis in mice with ameliorated side effects. In conclusion, all these data illustrated that FLD and DDP combinational treatment effectively restrained NSCLC progression, and thus can be served as a promising therapeutic strategy., (Copyright © 2022. Published by Elsevier Inc.)

Advances in structural biology have been fueled in part by developing techniques for large-scale heterologous expression and purification of proteins. Nevertheless, this step is still a bottleneck in biophysical studies of many proteins. Often, fusion proteins are used to increase expression levels, solubility, or both. Here, we compare a recently reported fusion tag, NT*, with Maltose Binding Protein (MBP), a well-known fusion tag and solubility enhancer. NT* shows high expression and solubility when used as an N-terminal fusion partner for several aggregation-prone peptides. Its efficacy in enhancing the solubility of aggregation-prone globular proteins has, however, not been tested. We find here that although the overall expression levels for NT* fusions are much higher than those for the MBP fusion, MBP was far superior for enhancing the solubility of the passenger protein. Nevertheless, the effective yield after purification from the soluble fraction of both MBP-fusion and NT*-fusion was comparable, mainly due to higher expression levels in NT*-fusion and a smaller fraction of the passenger protein net weight being locked in the fusion protein. We conclude that NT* is an excellent fusion tag to improve the overall expression of globular proteins but does not increase the passenger protein's solubility compared to MBP. Proteins that are partially soluble or can be refolded in-vitro will significantly benefit from N-terminal NT* fusions. MBP, however, still remains one of the very few options for an N-terminal fusion if the solubility of the protein after expression is critical for preserving its proper fold or activity., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Dual specificity phosphatase 22 (DUSP22), also named as Jun N-terminal kinase pathway associated phosphatase recently, is reported to be closely engaged in immune and inflammation regulation. This study aimed to investigate the interaction between synovium DUSP22 and serum DUSP22 levels and to explore their correlation with rheumatoid arthritis (RA) risk, inflammation, and disease activity., Methods: Synovium and serum samples from 42 RA patients with knee involvement underwent arthroscopy, and 20 knee trauma patients were collected. Besides, serum samples from 40 healthy controls were also obtained. Synovium DUSP22 expression was detected by reverse transcription quantitative polymerase chain reaction, while serum DUSP22 level was detected by enzyme-linked immunosorbent assay., Results: Synovium DUSP22 level was greatly decreased in RA patients compared to trauma controls (p < 0.001), and it was negatively correlated with tender joint count (TJC) (r = -0.318, p = 0.040), C-reactive protein (CRP) (r = -0.330, p = 0.033), and Lysholm score (r = -0.423, p = 0.005) in RA patients. Serum DUSP22 level was lowest in RA patients, followed by trauma controls, then highest in healthy controls (p < 0.001). Serum DUSP22 level was negatively associated with TJC (r = -0.438, p = 0.004), swollen joint count (SJC) (r = -0.372, p = 0.015), CRP (r = -0.391, p = 0.011), and disease activity score in 28 joints (DAS28 ESR ) score (r = -0.406, p = 0.008), and it increased after treatment (p = 0.001) in RA patients. In addition, serum DUSP22 level positively related to synovium DUSP22 level in RA patients (r = 0.394, p = 0.010)., Conclusion: Synovium and serum DUSP22 are intercorrelated and insufficiently expressed in RA patients; meanwhile, their deficiency correlates with increased systemic inflammation, disease activity, and joint dysfunction., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Activation of the type I angiotensin receptor (AT1-R) in vascular smooth muscle cells (VSMCs) plays a crucial role in the regulation of blood pressure; however, it is also responsible for the development of pathological conditions such as vascular remodeling, hypertension and atherosclerosis. Stimulation of the VSMC by angiotensin II (AngII) promotes a broad variety of biological effects, including gene expression changes. In this paper, we have taken an integrated approach in which an analysis of AngII-induced gene expression changes has been combined with the use of small-molecule inhibitors and lentiviral-based gene silencing, to characterize the mechanism of signal transduction in response to AngII stimulation in primary rat VSMCs. We carried out Affymetrix GeneChip experiments to analyze the effects of AngII stimulation on gene expression; several genes, including DUSP5 , DUSP6 , and DUSP10 , were identified as upregulated genes in response to stimulation. Since various dual-specificity MAPK phosphatase (DUSP) enzymes are important in the regulation of mitogen-activated protein kinase (MAPK) signaling pathways, these genes have been selected for further analysis. We investigated the kinetics of gene-expression changes and the possible signal transduction processes that lead to altered expression changes after AngII stimulation. Our data shows that the upregulated genes can be stimulated through multiple and synergistic signal transduction pathways. We have also found in our gene-silencing experiments that epidermal growth factor receptor (EGFR) transactivation is not critical in the AngII-induced expression changes of the investigated genes. Our data can help us understand the details of AngII-induced long-term effects and the pathophysiology of AT1-R. Moreover, it can help to develop potential interventions for those symptoms that are induced by the over-functioning of this receptor, such as vascular remodeling, cardiac hypertrophy or atherosclerosis.

Osteoarthritis (OA) is a proverbial inflammatory degenerative joint disease associated with the acceleration of the aging process and is characterized by chondrocyte injury and articular cartilage degradation. Dual-specificity phosphatase 14 (Dusp14), a common member of the DUSP family, has been implicated in multiple inflammatory diseases and bone loss. Nevertheless, the function of DUSP14 in OA remains unclear. In the present study, down-regulation of DUSP14 was corroborated in anterior cruciate ligament transection (ACLT)-induced OA rats and interleukin-1β (IL-1β)-stimulated chondrocytes. Additionally, the gain of DUSP14 reversed IL-1β-induced inhibition of chondrocyte viability but attenuated cell apoptosis. Concomitantly, DUSP14 overexpression muted IL-1β-induced release of pro-inflammatory mediators NO and prostaglandin E2 (PGE2), as well as pro-inflammatory cytokine levels (IL-6 and TNF-α). Furthermore, up-regulation of DUSP14 overturned the effects of IL-1β on the inhibition of collagen II and aggrecan expression, and enhancement of A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS5) and matrix metalloproteinases (MMPs; MMP3 and MMP-13). Mechanistically, DUSP14 elevation increased the p-Adenosine 5'-monophosphate-activated protein activated protein kinase(AMPK), inhibitor of NF-κB (IκB) expression and decreased p-p65 NF-κB expression, indicating that DUSP14 might restore the AMPK-IκB pathway to restrain NF-κB signaling under IL-1β exposure. Notably, blockage of AMPK signaling muted the protective efficacy of DUSP14 elevation against IL-1β-induced inflammatory injury and metabolism disturbance in chondrocytes. Interestingly, histological evaluation substantiated that DUSP14 injection alleviated cartilage degradation in OA rats. Together, DUSP14 may ameliorate OA progression by affecting chondrocyte injury, inflammatory response and cartilage metabolism homeostasis, implying a promising therapeutic strategy against OA.

Hypoxia, or low oxygen tension, is a hallmark of the tumor microenvironment. The hypoxia-inducible factor-1α (HIF-1α) subunit plays a critical role in the adaptive cellular response of hypoxic tumor cells to low oxygen tension by activating gene-expression programs that control cancer cell metabolism, angiogenesis, and therapy resistance. Phosphorylation is involved in the stabilization and regulation of HIF-1α transcriptional activity. HIF-1α is activated by several factors, including the mitogen-activated protein kinase (MAPK) superfamily. MAPK phosphatase 3 (MKP-3) is a cytoplasmic dual-specificity phosphatase specific for extracellular signal-regulated kinase 1/2 (Erk1/2). Recent evidence indicates that hypoxia increases the endogenous levels of both MKP-3 mRNA and protein. However, its role in the response of cells to hypoxia is poorly understood. Herein, we demonstrated that small-interfering RNA (siRNA)-mediated knockdown of MKP-3 enhanced HIF-1α (not HIF-2α) levels. Conversely, MKP-3 overexpression suppressed HIF-1α (not HIF-2α) levels, as well as the expression levels of hypoxia-responsive genes ( LDHA , CA9 , GLUT-1 , and VEGF ), in hypoxic colon cancer cells. These findings indicated that MKP-3, induced by HIF-1α in hypoxia, negatively regulates HIF-1α protein levels and hypoxia-responsive genes. However, we also found that long-term hypoxia ( > 12 h) induced proteasomal degradation of MKP-3 in a lactic acid-dependent manner. Taken together, MKP-3 expression is modulated by the hypoxic conditions prevailing in colon cancer, and plays a role in cellular adaptation to tumor hypoxia and tumor progression. Thus, MKP-3 may serve as a potential therapeutic target for colon cancer treatment.

Mitogen-activated protein kinases (MAPKs) are essential for proper cell functioning as they regulate many molecular effectors. Careful regulation of MAPKs is therefore required to avoid MAPK pathway dysfunctions and pathologies. The mammalian genome encodes about 200 phosphatases, many of which dephosphorylate the MAPKs and bring them back to an inactive state. In this review, we focus on the normal and pathological functions of dual-specificity phosphatase 9 ( DUSP9 )/MAP kinase phosphatases-4 (MKP-4). This cytoplasmic phosphatase, which belongs to the threonine/tyrosine dual-specific phosphatase family and was first described in 1997, is known to dephosphorylate ERK1/2, p38, JNK and ASK1, and thereby to control various MAPK pathway cascades. As a consequence, DUSP9 plays a major role in human pathologies and more specifically in cardiac dysfunction, liver metabolic syndromes, diabetes, obesity and cancer including drug response and cell stemness. Here, we recapitulate the mechanism of action of DUSP9 in the cell, its levels of regulation and its roles in the most frequent human diseases, and discuss its potential as a therapeutic target.

Dual specificity phosphatase 4 (DUSP4) is a prognostic marker and potential target of papillary thyroid carcinoma (PTC); however, the molecular mechanism underlying DUSP4-regulated PTC carcinogenesis is unknown. DUSP4 is a negative regulator of the autophagy promoter, JNK. This study explored the relationship between DUSP4 and JNK-mediated autophagic cell death in PTC, and the roles of DUSP4 in PTC using gain-of-function and loss-of-function assays. In addition, we further identified the significance of the JNK-BCL2-Beclin1-autophagy signaling pathway on DUSP4-regulated PTC carcinogenesis by combining knockdown of DUSP4 with a JNK-specific inhibitor (SP600125). We found that knockdown of DUSP4 promoted the phosphorylation of JNK and BCL2 in PTC cells, and enhanced the release of Beclin1 from the BCL2-Beclin1 complex. Knockdown of DUSP4 promoted autophagy and the death of PTC cells. The death and autophagy enhanced by knockdown of DUSP4 was reversed by the JNK inhibitor. We further extended the in-vitro experiments by subcutaneously injecting nude mice with K1 cells transfected with DUSP4-silencing vector. In-vivo assays showed that knockdown of DUSP4 not only inhibited tumor growth, but also promoted the phosphorylation of JNK and BCL2 and the expression of LC3II. In conclusion, DUSP4 inhibits BCL2-Beclin1-autophagy signaling by negatively regulating JNK activity, thus inhibiting PTC oncogenesis. The data from this study contribute to the prevention and cure of PTC.

Background: Pathogenic coronaviruses include Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2. These viruses have induced outbreaks worldwide, and there are currently no effective medications against them. Therefore, there is an urgent need to develop potential drugs against coronaviruses., Methods: High-throughput technology is widely used to explore differences in messenger (m)RNA and micro (mi)RNA expression profiles, especially to investigate protein-protein interactions and search for new therapeutic compounds. We integrated miRNA and mRNA expression profiles in MERS-CoV-infected cells and compared them to mock-infected controls from public databases., Results: Through the bioinformatics analysis, there were 251 upregulated genes and eight highly differentiated miRNAs that overlapped in the two datasets. External validation verified that these genes had high expression in MERS-CoV-infected cells, including RC3H1, NF-κB, CD69, TNFAIP3, LEAP-2, DUSP10, CREB5, CXCL2, etc. We revealed that immune, olfactory or sensory system-related, and signal-transduction networks were discovered from upregulated mRNAs in MERS-CoV-infected cells. In total, 115 genes were predicted to be related to miRNAs, with the intersection of upregulated mRNAs and miRNA-targeting prediction genes such as TCF4, NR3C1, and POU2F2. Through the Connectivity Map (CMap) platform, we suggested potential compounds to use against MERS-CoV infection, including diethylcarbamazine, harpagoside, bumetanide, enalapril, and valproic acid., Conclusions: The present study illustrates the crucial roles of miRNA-mRNA interacting networks in MERS-CoV-infected cells. The genes we identified are potential targets for treating MERS-CoV infection; however, these could possibly be extended to other coronavirus infections., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021. Published by Elsevier B.V.)

Dual specificity phosphatase 4 (DUSP4), a member of the dual specificity phosphatase family, is responsible for the dephosphorylation and inactivation of ERK, JNK and p38, which are mitogen-activated protein kinases involved in cell proliferation, differentiation and apoptosis, but also in inflammation processes. Given its importance for cellular signalling, DUSP4 is subjected to a tight regulation and there is growing evidence that its expression is dysregulated in several tumours. However, the mechanisms underlying DUSP4 transcriptional regulation remain poorly understood. Here, we analysed the regulation of the human DUSP4 promoters 1 and 2, located upstream of exons 1 and 2, respectively, by the cancer-related transcription factors (TFs) STAT3, FOXA1, CTCF and YY1. The presence of binding sites for these TFs was predicted in both promoters through the in silico analysis of DUSP4, and their functionality was assessed through luciferase activity assays. Regulatory activity of the TFs tested was found to be promoter-specific. While CTCF stimulated the activity of promoter 2 that controls the transcription of variants 2 and X1, STAT3 stimulated the activity of promoter 1 that controls the transcription of variant 1. YY1 positively regulated both promoters, although to different extents. Through site-directed mutagenesis, the functionality of YY1 binding sites present in promoter 2 was confirmed. This study provides novel insights into the transcriptional regulation of DUSP4, contributing to a better comprehension of the mechanisms of its dysregulation observed in several types of cancer., (© 2021 Wiley Periodicals LLC.)

Aims: The morbidity and mortality rates of calcific aortic valve disease (CAVD) remain high while treatment options are limited. Here, we evaluated the role and therapeutic value of dual-specificity phosphatase 26 (DUSP26) in CAVD., Methods and Results: Microarray profiling of human calcific aortic valves and normal controls demonstrated that DUSP26 was significantly up-regulated in calcific aortic valves. ApoE-/- mice fed a normal diet or a high cholesterol diet (HCD) were infected with adeno-associated virus serotype 2 carrying DUSP26 short-hairpin RNA to examine the effects of DUSP26 silencing on aortic valve calcification. DUSP26 silencing ameliorated aortic valve calcification in HCD-treated ApoE-/- mice, as evidenced by reduced thickness and calcium deposition in the aortic valve leaflets, improved echocardiographic parameters (decreased peak transvalvular jet velocity and mean transvalvular pressure gradient, as well as increased aortic valve area), and decreased levels of osteogenic markers (Runx2, osterix, and osteocalcin) in the aortic valves. These results were confirmed in osteogenic medium-induced human valvular interstitial cells. Immunoprecipitation, liquid chromatography-tandem mass spectrometry, and functional assays revealed that dipeptidyl peptidase-4 (DPP4) interacted with DUSP26 to mediate the procalcific effects of DUSP26. High N6-methyladenosine levels up-regulated DUSP26 in CAVD; in turn, DUSP26 activated DPP4 by antagonizing mouse double minute 2-mediated ubiquitination and degradation of DPP4, thereby promoting CAVD progression., Conclusion: DUSP26 promotes aortic valve calcification by inhibiting DPP4 degradation. Our findings identify a previously unrecognized mechanism of DPP4 up-regulation in CAVD, suggesting that DUSP26 silencing or inhibition is a viable therapeutic strategy to impede CAVD progression., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Reversible phosphorylation of proteins, controlled by kinases and phosphatases, is involved in various cellular processes. Dual-specificity phosphatases (DUSPs) can dephosphorylate phosphorylated serine, threonine and tyrosine residues. This family consists of 61 members, 44 of which have been identified in human, and these 44 members are classified into six subgroups, the phosphatase and tensin homolog (PTEN) protein phosphatases (PTENs), mitogen-activated protein kinase phosphatases (MKPs), atypical DUSPs, cell division cycle 14 (CDC14) phosphatases (CDC14s), slingshot protein phosphatases (SSHs), and phosphatases of the regenerating liver (PRLs). Growing evidence has revealed dysregulation of DUSPs as one of the common phenomenons and highlighted their key roles in human cancers. Furthermore, their differential expression may be a potential biomarker for tumor prognosis. Despite this, there are still many unstudied members of DUSPs need to further explore their precise roles and mechanism in cancers. Most importantly, the systematic review is very limited on the functional/mechanistic characteristics and clinical application of DUSPs at present. In this review, the structures, functions and underlying mechanisms of DUSPs are systematically reviewed, and the molecular and functional characteristics of DUSPs in different tumor types according to the current researches are summarized. In addition, the potential roles of the unstudied members and the possible different mechanisms of DUSPs in cancer are discussed and classified based on homology alignment and structural domain analyses. Moreover, the specific characteristics of their expression and prognosis are further determined in more than 30 types of human cancers by using the online databases. Finally, their potential application in precise diagnosis, prognosis and treatment of different types of cancers, and the main possible problems for the clinical application at present are prospected., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Pressure overload and other stress stimuli elicit a host of adaptive and maladaptive signaling cascades that eventually lead to cardiac hypertrophy and heart failure. Among those, the mitogen-activated protein kinase (MAPK) signaling pathway has been shown to play a prominent role. The dual specificity phosphatases (DUSPs), also known as MAPK specific phosphatases (MKPs), that can dephosphorylate the MAPKs and inactivate them are gaining increasing attention as potential drug targets. Here we try to review recent advancements in understanding the roles of the different DUSPs, and the pathways that they regulate in cardiac remodeling. We focus on the regulation of three main MAPK branches - the p38 kinases, the c-Jun-N-terminal kinases (JNKs) and the extracellular signal-regulated kinases (ERK) by various DUSPs and try to examine their roles., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Mitogen-activated protein kinases (MAPKs) are inactivated by dual-specificity phosphatases (DUSPs), the activities of which are tightly regulated during cell differentiation. Using knockdown screening and single-cell transcriptional analysis, we demonstrate that DUSP4 is the phosphatase that specifically inactivates p38 kinase to promote megakaryocyte (Mk) differentiation. Mechanistically, PRMT1-mediated methylation of DUSP4 triggers its ubiquitinylation by an E3 ligase HUWE1. Interestingly, the mechanistic axis of the DUSP4 degradation and p38 activation is also associated with a transcriptional signature of immune activation in Mk cells. In the context of thrombocytopenia observed in myelodysplastic syndrome (MDS), we demonstrate that high levels of p38 MAPK and PRMT1 are associated with low platelet counts and adverse prognosis, while pharmacological inhibition of p38 MAPK or PRMT1 stimulates megakaryopoiesis. These findings provide mechanistic insights into the role of the PRMT1-DUSP4-p38 axis on Mk differentiation and present a strategy for treatment of thrombocytopenia associated with MDS., Competing Interests: Declaration of interests M.L. has served on the Scientific Advisory Board for Epi One. A.V. has received research funding from GlaxoSmithKline, Incyte, MedPacto, Novartis, Curis, and Eli Lilly and Company; has received compensation as a scientific advisor to Novartis, Stelexis Therapeutics, Acceleron Pharma, and Celgene; and has equity ownership in Stelexis Therapeutics. The remaining authors declare no competing interests. Array BioPharma provided the p38 inhibitor pexmetinib (ARRY614) and participated in its phase I study (ClinicalTrials.gov: NCT01496495)., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Drug resistance is a major obstacle to the treatment of most human tumors. In this study, we find that dual-specificity phosphatase 16 (DUSP16) regulates resistance to chemotherapy in nasopharyngeal carcinoma, colorectal cancer, gastric and breast cancer. Cancer cells expressing higher DUSP16 are intrinsically more resistant to chemotherapy-induced cell death than cells with lower DUSP16 expression. Overexpression of DUSP16 in cancer cells leads to increased resistance to cell death upon chemotherapy treatment. In contrast, knockdown of DUSP16 in cancer cells increases their sensitivity to treatment. Mechanistically, DUSP16 inhibits JNK and p38 activation, thereby reducing BAX accumulation in mitochondria to reduce apoptosis. Analysis of patient survival in head & neck cancer and breast cancer patient cohorts supports DUSP16 as a marker for sensitivity to chemotherapy and therapeutic outcome. This study therefore identifies DUSP16 as a prognostic marker for the efficacy of chemotherapy, and as a therapeutic target for overcoming chemoresistance in cancer.

Background: This study aimed to investigate the relationship of serum JNK pathway-associated phosphatase (JKAP) expression with rheumatoid arthritis (RA) risk and clinical features, also to explore the longitudinal change of JKAP during etanercept treatment and its relationship with etanercept treatment response in RA patients., Methods: A total of 87 RA patients and 44 healthy controls (HCs) were enrolled; then, their JKAP expression in serum was determined by enzyme-linked immunosorbent assay (ELISA). Among 87 RA patients, 42 cases further received the 24-week etanercept treatment; then, their JKAP level in serum (detected by ELISA) and clinical response (evaluated by disease activity score in 28 joints (DAS28) score) were evaluated at week 4 (W4), week 12 (W12), and week 24 (W24) after initiation of etanercept treatment., Results: JKAP expression was decreased in RA patients compared to HCs, which disclosed a good predictive value for RA risk. JKAP expression was negatively associated with tender joint count, swollen joint count, erythrocyte sedimentation rate, C-reactive protein, and DAS28 in RA patients, respectively. For RA patients who received 24-week etanercept treatment, their clinical response rate was 0.0%, 33.3%, 50.0%, and 69% at W0, W4, W12, and W24, respectively. Importantly, JKAP was gradually increased during etanercept treatment, whose longitudinal elevation positively related to etanercept treatment response in RA patients., Conclusion: Circulating JKAP links with decreased RA risk and mild disease activity, whose longitudinal elevation positively relates to etanercept treatment response., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Background: The vital roles of circular RNAs in human cancers have been demonstrated. In this study, we aimed to investigate the functions of circDUSP16 in esophageal squamous cell carcinoma (ESCC) development., Methods: Quantitative real-time polymerase chain reaction was executed for the expression levels of circDUSP16, DUSP16, miR-497-5p, and transketolase-like-1 (TKTL1) messenger RNA. Actinomycin D assay and RNase R digestion assay were used to determine the characteristics of circDUSP16. Cell Counting Kit-8 assay and colony formation assay were applied for cell proliferation. Transwell assay was performed to assess cell migration and invasion. The glycolysis level was evaluated using specific kits. Protein levels were measured by Western blot assay. RNA pull-down assay and dual-luciferase reporter assay were adopted to explore the relationships among circDUSP16, miR-497-5p, and TKTL1. Murine xenograft model was used to determine the role of circDUSP16 in ESCC in vivo., Results: CircDUSP16 level was elevated in ESCC tissues, cells, and hypoxia-stimulated ESCC cells. Knockdown of circDUSP16 suppressed hypoxia-induced ESCC cell viability, colony formation, migration, invasion, and glycolysis. For mechanism analysis, circDUSP16 could positively regulate TKTL1 expression by sponging miR-497-5p in ESCC cells. Moreover, miR-497-5p inhibition restored the effects of circDUSP16 knockdown on the malignant behaviors of ESCC cells under hypoxia condition. MiR-497-5p overexpression suppressed hypoxia-induced ESCC cell progression by targeting TKTL1. In addition, circDUSP16 knockdown repressed the tumorigenesis of ESCC in vivo., Conclusions: CircDUSP16 knockdown suppressed hypoxia-induced ESCC cell growth, invasion, and glycolysis by regulating TKTL1 expression through sponging miR-497-5p., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Dual specificity phosphatases (DUSPs) play a crucial role in the regulation of intracellular signalling pathways, which in turn influence a broad range of physiological processes. DUSP malfunction is increasingly observed in a broad range of human diseases due to deregulation of key pathways, most notably the MAP kinase (MAPK) cascades. Dual specificity phosphatase 26 (DUSP26) is an atypical DUSP with a range of physiological substrates including the MAPKs. The residues that govern DUSP26 substrate specificity are yet to be determined; however, recent evidence suggests that interactions with a binding partner may be required for DUSP26 catalytic activity. DUSP26 is heavily implicated in cancer where, akin to other DUSPs, it displays both tumour-suppressive and -promoting properties, depending on the context. Here we review DUSP26 by evaluating its transcriptional patterns, protein crystallographic structure and substrate binding, as well as its physiological role(s) and binding partners, its role in human disease and the development of DUSP26 inhibitors.

Elucidating virus-cell interactions is fundamental to understanding viral replication and identifying targets for therapeutic control of viral infection. The extracellular signal-regulated kinase (ERK) pathway has been shown to regulate pathogenesis during many viral infections, but its role during coronavirus infection is undetermined. Infectious bronchitis virus is the representative strain of Gammacoronavirus, which causes acute and highly contagious diseases in the poultry farm. In this study, we investigated the role of ERK1/2 signaling pathway in IBV infection. We found that IBV infection activated ERK1/2 signaling and the up-regulation of phosphatase DUSP6 formed a negative regulation loop. Pharmacological inhibition of MEK1/2-ERK1/2 signaling suppressed the expression of DUSP6, promoted cell death, and restricted virus replication. In contrast, suppression of DUSP6 by chemical inhibitor or siRNA increased the phosphorylation of ERK1/2, protected cells from apoptosis, and facilitated IBV replication. Overexpression of DUSP6 decreased the level of phospho-ERK1/2, promoted apoptosis, while dominant negative mutant DUSP6-DN lost the regulation function on ERK1/2 signaling and apoptosis. In conclusion, these data suggest that MEK-ERK1/2 signaling pathway facilitates IBV infection, probably by promoting cell survival; meanwhile, induction of DUSP6 forms a negative regulation loop to restrict ERK1/2 signaling, correlated with increased apoptosis and reduced viral load. Consequently, components of the ERK pathway, such as MEK1/2 and DUSP6, represent excellent targets for the development of antiviral drugs.