Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The accumulation of apoptotic cells is one of the pathological characteristics of systemic lupus erythematosus (SLE). The expression of urokinase-type plasminogen activator receptor (uPAR) has been reported to be increased in SLE patients and to be involved in macrophage efferocytosis. Although the toll-like receptor 7 (TLR7) is also over-expressed in lupus, its relationship to uPAR and its role in macrophage efferocytosis in lupus is still unclear. In the present study, we revealed that apoptotic cells accumulate in the spleen, macrophage efferocytosis is impaired, and uPAR is increased in the spleen and peritoneal macrophages of the TLR7 agonist imiquimod (IMQ)-induced SLE mouse model. Moreover, TLR7 upregulated uPAR expression in the mouse macrophage RAW 264.7 cells in vitro. The same results were also obtained using peritoneal macrophages of female Balb/c mice. When uPAR levels in peritoneal macrophages were knocked down by siRNA or inhibited by the peptide inhibitor UPARANT, and cells further treated with the TLR7 agonist R848, efferocytosis of peritoneal macrophages on apoptotic cells was restored. These results indicated that TLR7 activation impaired efferocytosis via uPAR in mouse peritoneal macrophages. Furthermore, TLR7 regulated uPAR expression via ERK/JNK signaling in macrophages. These results suggest that uPAR may be an important factor related to the accumulation of apoptotic cells in SLE.
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PMID:Urokinase-type plasminogen activator receptor is required for impairing toll-like receptor 7 signaling on macrophage efferocytosis in lupus. 3291 23

Exosomes (Exos) have been reported to promote pre-metastatic niche formation, proliferation, angiogenesis and metastasis. We have investigated the role of uPAR in melanoma cell lines-derived Exos and their pro-angiogenic effects on human microvascular endothelial cells (HMVECs) and endothelial colony-forming cells (ECFCs). Melanoma Exos were isolated from conditioned media of A375 and M6 cells by differential centrifugation and filtration. Tunable Resistive Pulse Sensing (TRPS) and Nanoparticle tracking analysis were performed to analyze dimension and concentration of Exos. The CRISPR-Cas 9 technology was exploited to obtain a robust uPAR knockout. uPAR is expressed in melanoma Exos that are internalized by HMVECs and ECFCs, enhancing VE-Cadherin, EGFR and uPAR expression in endothelial cells that undergo a complete angiogenic program, including proliferation, migration and tube formation. uPAR loss reduced the pro-angiogenic effects of melanoma Exos in vitro and in vivo by inhibition of VE-Cadherin, EGFR and uPAR expression and of ERK1,2 signaling in endothelial cells. A similar effect was obtained with a peptide that inhibits uPAR-EGFR interaction and with the EGFR inhibitor Gefitinib, which also inhibited melanoma Exos-dependent EGFR phosphorylation. This study suggests that uPAR is required for the pro-angiogenic activity of melanoma Exos. We propose the identification of uPAR-expressing Exos as a potentially useful biomarker for assessing pro-angiogenic propensity and eventually monitoring the response to treatment in metastatic melanoma patients.
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PMID:uPAR-expressing melanoma exosomes promote angiogenesis by VE-Cadherin, EGFR and uPAR overexpression and rise of ERK1,2 signaling in endothelial cells. 3323 52


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