• Journal of Life Science
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• v.21 no.1
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• pp.31-35
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• 2011

Dual-specificity protein phosphatases (DUSPs) constitute a family of protein phosphatase characterized by the ability to dephosphorylate phospho-tyrosyl and phospho-seryl/threonyl residues. Most DUSPs are involved in regulation of cell survival and differentiation. In this study, a human dual-specificity protein phosphatase, DUSP28, was isolated from a human kidney cDNA. The recombinant protein was successfully produed in E.coli and showed sufficient phosphatase activity toward DiFMUP (6,8-difluoro-4-methylumbelliferyl phosphate). Various phosphatase inhibitors and divalent metals were tested for their effects on the DUSP28 phosphatase activity. As a result, $Zn^{2+}$ was found to strongly inhibit DUSP28 phosphatase activity, suggesting DUSP28 is involved in Zn-related signal transduction pathway. Furthermore, the DUSP28 protein preferred phospho-tyrosyl residues to phospho-threonyl residues, implying its physiological roles in the cellular process.

• The Korean Journal of Pain
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• v.37 no.4
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• pp.320-331
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• 2024

Background: MicroRNA (miRNA) plays a crucial role in neuropathic pain (NP) by targeting mRNAs. This study aims to analyze the regulatory function and mechanism of miR-382-5p/dual specificity phosphatase-1 (DUSP1) axis in NP. Methods: We utilized rats with chronic constriction injury (CCI) of the sciatic nerve as the NP model. The levels of miR-382-5p and DUSP1 were reduced by intrathecal injection of lentiviral interference vectors targeting miR-382-5p and DUSP1. The mRNA levels of miR-382-5p and DUSP1 in the dorsal root ganglions (DRGs) were measured by RT-qPCR assay. The pain behavior was evaluated by mechanical nociceptive sensitivity and thermal nociceptive sensitivity. The expression levels of interleukin-6 (IL)-6, IL-1β, and tumor necrosis factor-α in the DRGs were analyzed by ELISA assay. The targeting relationship between miR-382-5p and DUSP1 was verified by DLR assay and RIP assay. Results: Compared to the Sham group, the CCI rats exhibited higher levels of miR-382-5p and lower levels of DUSP1. Overexpression of miR-382-5p significantly decreased DUSP1 levels. Reducing miR-382-5p levels can lower the mechanical nociceptive sensitivity and thermal nociceptive sensitivity of CCI rats and inhibit the over-activation of pro-inflammatory factors. Reduced miR-382-5p levels decreased NP in CCI rats. DUSP1 is the target of miR-382-5p, and down-regulation of DUSP1 reverses the inhibitory effect of reduced miR-382-5p levels on NP. Conclusions: Down-regulation of miR-382-5p inhibits the over-activation of pro-inflammatory factors by targeting and regulating the expression of DUPS1, thereby alleviating NP.

• Molecules and Cells
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• v.42 no.2
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• pp.183-188
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• 2019

Osteoarthritis (OA) is a naturally occurring, irreversible disorder and a major health burden. The disease is multifactorial, involving both physiological and mechanical processes, but calcium crystals have been associated intimately with its pathogenesis. This study tested the hypothesis that these crystals have a detrimental effect on the differentiation of osteoclasts and bone homeostasis. This study employed an osteoblastosteoclast coculture system that resembles in vivo osteoblastdependent osteoclast differentiation along with $Ca^{2+}$-phosphate-coated culture dishes. The calcium-containing crystals upregulated the expression of RANKL and increased the differentiation of osteoclasts significantly as a result. On the other hand, osteoblast differentiation was unaffected. MicroRNA profiling showed that dual-specificity phosphatases 1 (DUSP1) was associated with the increased RANKL expression. DUSP1 belongs to a family of MAPK phosphatases and is known to inactivate all three groups of MAPKs, p38, JNK, and ERK. Furthermore, knockdown of DUSP1 gene expression suggested that RANKL expression increases significantly in the absence of DUSP1 regulation. Microarray analysis of the DUSP1 mRNA levels in patients with pathological bone diseases also showed that the downregulated DUSP1 expression leads to increased expression of RANKL and consequently to the destruction of the bone observed in these patients. These findings suggest that calcium-containing crystals may play a crucial role in promoting RANKL-induced osteoclastogenesis via DUSP1.

• Journal of Yeungnam Medical Science
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• v.30 no.1
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• pp.10-16
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• 2013

Background: Toll-like receptors (TLRs) are well-known pattern recognition receptors. Among the 13 TLRs, TLR2 is the most known receptor for immune response. It activates mitogen-activated protein kinases (MAPKs), which are counterbalanced by MAPK phosphatases [MKPs or dual-specificity phosphatases (DUSPs)]. However, the regulatory mechanism of DUSPs is still unclear. In this study, the effect of a TLR2 ligand (TLR2L, Pam3CSK4) on DUSP4 expression in Raw264.7 cells was demonstrated. Methods: A Raw264.7 mouse macrophage cell line was cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and 1% antibiotics (100 U/mL penicillin and 100 g/mL streptomycin) at $37^{\circ}C$ in 5% $CO_2$. TLR2L (Pam3CSK4)-mediated DUSP4 expressions were confirmed with RT-PCR and western blot analysis. In addition, the detection of reactive oxygen species (ROS) was measured with lucigenin assay. Results: Pam3CSK4 induced the expression of DUSP1, 2, 4, 5 and 16. The DUSP4 expression was also increased by TLR4 and 9 agonists (lipopolysaccharide and CpG ODN, respectively). Pam3CSK4 also induced ERK1/2 phosphorylation and ROS production, and the Pam3CSK4-induced DUSP4 expression was decreased by ERK1/2 (U0126) and ROS (DPI) inhibitors. U0126 suppressed the ROS production by Pam3CSK4. Conclusion: Pam3CSK4-mediated DUSP4 expression is regulated by ERK1/2 and ROS. This finding suggests the physiological importance of DUSP4 in TLR2-mediated immune response.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1909-1912
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• 2013

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3835-3837
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• 2012

• IMMUNE NETWORK
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• v.16 no.2
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• pp.85-98
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• 2016

The mitogen-activated protein kinases (MAPKs) are key regulators of cell growth and survival in physiological and pathological processes. Aberrant MAPK signaling plays a critical role in the development and progression of human cancer, as well as in determining responses to cancer treatment. The MAPK phosphatases (MKPs), also known as dual-specificity phosphatases (DUSPs), are a family of proteins that function as major negative regulators of MAPK activities in mammalian cells. Studies using mice deficient in specific MKPs including MKP1/DUSP1, PAC-1/DUSP2, MKP2/DUSP4, MKP5/DUSP10 and MKP7/DUSP16 demonstrated that these molecules are important not only for both innate and adaptive immune responses, but also for metabolic homeostasis. In addition, the consequences of the gain or loss of function of the MKPs in normal and malignant tissues have highlighted the importance of these phosphatases in the pathogenesis of cancers. The involvement of the MKPs in resistance to cancer therapy has also gained prominence, making the MKPs a potential target for anti-cancer therapy. This review will summarize the current knowledge of the MKPs in cancer development, progression and treatment outcomes.

• IMMUNE NETWORK
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• v.23 no.4
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• pp.34.1-34.15
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• 2023

Lung cancer, particularly non-small cell lung cancer (NSCLC) which contributes more than 80% to totally lung cancer cases, remains the leading cause of cancer death and the 5-year survival is less than 20%. Continuous understanding on the mechanisms underlying the pathogenesis of this disease and identification of biomarkers for therapeutic application and response to treatment will help to improve patient survival. Here we found that a molecule known as DUSP10 (also known as MAPK phosphatase 5) is oncogenic in NSCLC. Overexpression of DUSP10 in NSCLC cells resulted in reduced activation of ERK and JNK, but increased activation of p38, which was associated with increased cellular growth and migration. When inoculated in immunodeficient mice, the DUSP10-overexpression NSCLC cells formed larger tumors compared to control cells. The increased growth of DUSP10-overexpression NSCLC cells was associated with increased expression of tumor-promoting cytokines including IL-6 and TGFβ. Importantly, higher DUSP10 expression was associated with poorer prognosis of NSCLC patients. Therefore, DUSP10 could severe as a biomarker for NSCLC prognosis and could be a target for development of therapeutic method for lung cancer treatment.

• Korean Circulation Journal
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• v.54 no.5
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• pp.233-252
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• 2024

Background and Objectives: Myocardial ischemia-reperfusion injury (MIRI) refers to the damage of cardiac function caused by restoration of blood flow perfusion in ischemic myocardium. However, long non-coding RNA prostate androgen regulated transcript 1 (PART1)'s role in MIRI remain unclear. Methods: Immunofluorescence detected LC3 expression. Intermolecular relationships were verified by dual luciferase reporter assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry and transferase-mediated dUTP nick-end labeling (TUNEL) assays analyzed cell viability and apoptosis. The release of lactate dehydrogenase was tested via enzyme-linked immunosorbent assay (ELISA). Left anterior descending coronary artery surgery induced a MIRI mouse model. Infarct area was detected by 2,3,5-triphenyltetrazolium chloride staining. Hematoxylin and eosin staining examined myocardial injury. ELISA evaluated myocardial marker (creatine kinase MB) level. Results: PART1 was decreased in hypoxia/reoxygenation (H/R) induced AC16 cells and MIRI mice. PART1 upregulation attenuated the increased levels of Bax, beclin-1 and the ratio of LC3II/I, and enhanced the decrease of Bcl-2 and p62 expression in H/R-treated cells. PART1 upregulation alleviated H/R-triggered autophagy and apoptosis via miR-302a-3p. Mechanically, PART1 targeted miR-302a-3p to upregulate transcription factor activating enhancer-binding protein 2C (TFAP2C). TFAP2C silencing reversed the protected effects of miR-302a-3p inhibitor on H/R treated AC16 cells. We further established TFAP2C combined to dual-specificity phosphatase 5 (DUSP5) promoter and activated DUSP5. TFAP2C upregulation suppressed H/R-stimulated autophagy and apoptosis through upregulating DUSP5. Overexpressed PART1 reduced myocardial infarction area and attenuated MIRI in mice. Conclusion: PART1 improved the autophagy and apoptosis in H/R-exposed AC16 cells through miR-302a-3p/TFAP2C/DUSP5 axis, which might provide novel targets for MIRI treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.1925-1929
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• 2014

Background: Vascular endothelial growth factor-C (VEGF-C), which contributes to lymphatic metastasis (LM) in malignant disease, is one of the most important factors involved in physical and pathological lymphangiogenesis. Some VEGF-C related factors such as sine oculis homeobox homolog (SIX) 1, contactin (CNTN) 1 and dual specificity phosphatase (DUSP) 6 have been extensively studied in malignancies, but their expression levels and associations have still to be elucidated in stomach cancer. Methods: We detected their expression levels in 30 paired stomach cancer tissues using quantitative real-time reverse transcription-PCR (qRT-PCR). The expression and clinical significance of each factor was analyzed using Wilcoxon signed rank sum test. The correlation among all the factors was performed by Spearman rank correlation analysis. Results: The results suggest that VEGF-C and CNTN1 are significantly correlated with tumor size, SIX1 with the age and CNTN1 also with the cTNM stage. There are significant correlations of expression levels among VEGF-C, SIX1, CNTN1 and DUSP6. Conclusions: There exists an important regulatory crosstalk involving SIX1, VEGF-C, CNTN1 and DUSP6 in stomach cancer.