1: J Cell Sci. 2005 Jun 15;118(Pt 12):2743-53. Urokinase-induced activation of the gp130/Tyk2/Stat3 pathway mediates a pro-inflammatory effect in human mesangial cells via expression of the anaphylatoxin C5a receptor. Shushakova N, Tkachuk N, Dangers M, Tkachuk S, Park JK, Zwirner J, Hashimoto K, Haller H, Dumler I. Hannover Medical School, Germany. Glomerular mesangial cells (MCs) are central to the pathogenesis of progressive glomeruli-associated renal diseases. However, molecular mechanisms underlying changes in MC functions still remain poorly understood. Here, we show that in MCs, the urokinase-type plasminogen activator (uPA) induces, via its specific receptor (uPAR, CD87), upregulated expression of the complement anaphylatoxin C5a receptor (C5aR, CD88), and modulates C5a-dependent functional responses. This effect is mediated via the interaction of the uPA-specific receptor (uPAR, CD87) and gp130, a signal transducing subunit of the receptor complexes for the IL-6 cytokine family. The Janus kinase Tyk2 and the transcription factor Stat3 serve as downstream components in the signaling cascade resulting in upregulation of C5aR expression. In vivo, expression of C5aR and uPAR was increased in the mesangium of wild-type mice in a lipopolysaccharide (LPS)-induced model of inflammation, whereas in uPAR(-/-) animals C5aR expression remained unchanged. This is the first demonstration in vitro and in vivo that uPA acts in MCs as a modulator of immune responses via control of immune-competent receptors. The data suggest a novel role for uPA/uPAR in glomeruli-associated renal failure via a signaling cross-talk between the fibrinolytic and immune systems. PMID: 15944400 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 2: Nippon Geka Gakkai Zasshi. 2004 Oct;105(10):650-3. [Liver regeneration after resection: molecular and cellular mechanism] [Article in Japanese] Wakabayashi G, Shimazu M, Ueda M, Tanabe M, Kawachi S, Kitajima M. Department of Surgery, Keio University School of Medicine, Tokyo, Japan. It has been well established that the liver can regenerate after resection. Liver regeneration is a fundamental mechanism by which the liver responds to injury. This review article discusses molecular and cellular mechanism of liver regeneration, including growth factors and cytokines in the initiation and regulation of liver regeneration, the importance of the liver extracellular matrix and its dynamic effect on hepatocyte growth, and finally, stem cell biology in liver regeneration. Publication Types: Review Review, Tutorial PMID: 15521380 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: J Exp Ther Oncol. 2002 Nov-Dec;2(6):350-9. Epigallocatechin-3-gallate decreases VEGF production in head and neck and breast carcinoma cells by inhibiting EGFR-related pathways of signal transduction. Masuda M, Suzui M, Lim JT, Deguchi A, Soh JW, Weinstein IB. Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, HHSC-1509, 701 W. 168th Street, New York, NY 10032, USA. In a recent study on head and neck squamous cell carcinoma (HNSCC) cells we found that epigallocatechin-3-gallate (EGCG), a major biologically active component of green tea, inhibited activation of the epidermal growth factor receptor (EGFR) and related signaling pathways. Since activation of EGFR signaling pathways is associated with angiogenesis, we examined the effects of EGCG on vascular endothelial growth factor (VEGF) production by YCU-H891 HNSCC and MDA-MB-231 breast carcinoma cell lines, because we found that both of these cell lines display autocrine activation of transforming growth factor-alpha (TGF-alpha)/EGFR signaling and produce high levels of VEGF. Treatment with EGCG inhibited the constitutive activation of the EGFR, Stat3, and Akt in both cell lines. These changes were associated with inhibition of VEGF promoter activity and cellular production of VEGF. Mechanistic studies indicated that inhibition of Stat3, but not mitogen-activated protein kinase kinase (MEK)1 or phosphatidylinositol 3'-kinase (PI3K), significantly decreased VEGF promoter activity. However, the inhibitory effects of a dominant negative Stat3 on VEGF expression was not as strong as that produced by EGCG. An analysis of alternative pathways indicated that EGCG strongly inhibited the constitutive activation of NF-kappa B in both cell lines, and an NF-kappa B inhibitor strongly inhibited VEGF production. These results suggest that EGCG inhibits VEGF production by inhibiting both the constitutive activation of Stat3 and NF-kappa B, but not extracellular-signal-regulated kinase (ERK) or Akt, in these cells. Therefore, EGCG may be useful in treating HNSCC and breast carcinoma because it can exert both antiproliferative and antiangiogenic activities. PMID: 12440226 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 4: J Neurochem. 2002 Nov;83(3):696-703. Mechanism of plasminogen activator inhibitor-1 regulation by oncostatin M and interleukin-1 in human astrocytes. Kasza A, Kiss DL, Gopalan S, Xu W, Rydel RE, Koj A, Kordula T. Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA. Glial cells that produce and respond to various cytokines mediate inflammatory processes in the brain. Here, we show that oncostatin M (OSM) and interleukin-1 (IL-1) regulate the expression of plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator (uPA) in human astrocytes. Using the PAI-1 reporter constructs we show that the -58 to -51 proximal element mediates activation by both cytokines. This element is already bound by c-fos/c-jun heterodimers in unstimulated astrocytes, and treatment with cytokine strongly stimulates both expression of c-fos and binding of c-fos/c-jun heterodimers. In addition, IL-1 activates an inhibitory mechanism that down-regulates PAI-1 expression after longer exposure to this cytokine. Overexpression of dominant-negative signal transducer and activator of transcription-1 (STAT1), STAT3, STAT5 and inhibitor of nuclear factor-kappaB (IkappaB) suppressed OSM/IL-1-induced expression of the PAI-1 reporter construct. We conclude that OSM and IL-1 regulate the PAI-1 gene expression via up-regulating c-fos levels and subsequent binding of c-fos/c-jun heterodimers to the proximal element of the PAI-1 gene. PMID: 12390531 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 5: Int J Cancer. 2002 Aug 20;100(6):642-53. Erratum in: Int J Cancer. 2005 Dec 20;117(6):1065. Proiettii, Cecilia J [corrected to Proietti, Cecilia J]. Heregulin inhibits proliferation via ERKs and phosphatidyl-inositol 3-kinase activation but regulates urokinase plasminogen activator independently of these pathways in metastatic mammary tumor cells. Puricelli L, Proietti CJ, Labriola L, Salatino M, Balana ME, Aguirre Ghiso J, Lupu R, Pignataro OP, Charreau EH, Bal de Kier Joffe E, Elizalde PV. Instituto de Oncologia Angel H. Roffo, Universidad de Buenos Aires, Argentina. Heregulin (HRG) and type I receptor tyrosine kinase (RTK) expression was investigated in the highly invasive and metastatic LM3 cell line, our previously described model of metastasis for mammary cancer (Bal de Kier Joffe et al. [1986] Invasion Metastasis 6:302-12; Urtreger et al. [1997] Int J Oncol 11:489-96). Although LM3 cells do not express HRG, they exhibit high levels of ErbB-2 and ErbB-3 as well as moderate expression of ErbB-4. Addition of exogenous HRGbeta1 resulted in inhibition of both proliferation and migration of LM3 cells. HRGbeta1 was also able to decrease the activity of urokinase-type plasminogen activator (uPA) and matrix metalloproteinase 9 (MMP-9), 2 key enzymes in the invasion and metastatic cascade. HRGbeta1 treatment of LM3 cells induced tyrosine phosphorylation of ErbB-2, ErbB-3 and ErbB-4 as well as the formation of ErbB-2/ErbB-3 and ErbB-2/ErbB-4 heterodimers. Assessment of the signaling pathways involved in HRGbeta1 action indicated that the addition of HRGbeta1 to LM3 cells resulted in activation of phosphatidylinositol 3- kinase (PI-3K) and in strong induction of the association of the p85 subunit of PI-3K with ErbB-3. HRGbeta1 also caused the rapid activation of ERK1/ERK2 and Stat3 and Stat5 (signal transducers and activators of transcription [STAT]). This is the first demonstration of the ability of HRGbeta1 to activate STATs in mammary tumor cells. Blockage of PI-3K activity with its chemical inhibitor wortmannin, or of MEK1/ERKs activity with PD98059, resulted in suppression of the ability of HRGbeta1 to inhibit LM3 cell growth. Notwithstanding the suppression of these 2 signaling pathways, HRGbeta1 still proved capable of inhibiting uPA activity. Therefore, our results provide evidence that signaling pathways involved in HRGbeta1-induced proliferation appear to be distinct from those involved in HRGbeta1 regulation of uPA, a protease that plays a pivotal role in invasion and metastasis. Copyright 2002 Wiley-Liss, Inc. PMID: 12209601 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 6: J Biol Chem. 1999 Aug 20;274(34):24059-65. Urokinase induces activation and formation of Stat4 and Stat1-Stat2 complexes in human vascular smooth muscle cells. Dumler I, Kopmann A, Wagner K, Mayboroda OA, Jerke U, Dietz R, Haller H, Gulba DC. Franz Volhard Clinic and Max-Delbruck Center for Molecular Medicine, Virchow Klinikum-Charite, Humboldt University of Berlin, D-13125 Berlin, Germany. dumler@fvk-berlin.de Urokinase-type plasminogen activator (uPA) and its specific receptor (uPAR) act in concert to stimulate cytoplasmic signaling machinery and transcription factors responsible for cell migration and proliferation. Recently we demonstrated that uPA activates the Janus kinase/signal transducers and activators of transcription (Stat1) signaling in human vascular smooth muscle and endothelial cells. However, the important question whether other transcription factors of the Stat family, in addition to Stat1, are involved in the uPAR-related signaling has not been addressed. In this study, we demonstrate that Stat4 and Stat2, but not Stat3, Stat5, or Stat6, are rapidly activated in response to uPA. We demonstrate further that Stat4 and Stat2 rapidly and transiently translocate to the cell nucleus where they bind specifically to the regulatory DNA elements. Analysis of Stat complexes formed in response to uPA revealed a Stat2-Stat1 heterodimer, which lacks p48, a DNA-binding protein known to combine with Stat1-Stat2. This new uPA-induced Stat2-Stat1 heterodimer binds to GAS (the interferon-gamma activation site) distinct from the interferon-stimulated response element to which the p48 protein containing complexes generally bind. We conclude that uPA activates a specific and unusual subset of latent cytoplasmic transcription factors in human vascular smooth muscle cells that suggests a critical role of uPA in these cells. PMID: 10446176 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------