Plasminogen activator/plasmin system regulates formation of the hepatocyte spheroids

Hasebe, Yuichi; Akao, Makoto; Okumura, Nobuaki; Izumi, Takako; Koh, Tomohiko; Seki, Taiichiro; Ariga, Toshio

doi:10.1016/s0006-291x(03)01468-2

Cited by 18 publications

(16 citation statements)

References 31 publications

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“…The impairment of liver regeneration and abnormalities in liver repair have been observed in plasminogen-deficient mice, when they have undergone partial hepatectomy (8,9) or been treated with CCl 4 (10). We demonstrated that the plasminogen activator/plasmin system acts to enhance the formation of hepatocyte spheroids (11) and to promote the proliferation of hepatocytes in vitro (12). These results strongly suggest that plasmin(ogen) is a positive regulator for liver regeneration.…”

Section: Thrombin-activatable Fibrinolysis Inhibitor (Tafi)mentioning

confidence: 52%

A Novel Function of Thrombin-activatable Fibrinolysis Inhibitor during Rat Liver Regeneration and in Growth-promoted Hepatocytes in Primary Culture

Okumura

Koh

Hasebe

et al. 2009

Journal of Biological Chemistry

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Thrombin-activatable fibrinolysis inhibitor (TAFI) exhibits anti-fibrinolytic activity by removing C-terminal lysine residues from fibrin or plasminogen receptor proteins on the cellular surface, and plays an important role in the regulation of fibrinolysis. In this study, we examined the regulation of TAFI in hepatocytes during liver regeneration, and revealed its pivotal role in hepatocyte proliferation. In rat models, partial hepatectomy or carbon tetrachloride (CCl 4 )-induced acute liver injury suppressed the levels of plasma TAFI activity and hepatic TAFI mRNA, whereas this operation markedly increased both the hepatic plasmin activity and the level of proliferating cell nuclear antigen. In primary cultures of rat hepatocytes, the TAFI mRNA level was decreased under growth-promoting culture conditions. Treatment of the hepatocytes with TAFI siRNA increased the amount of plasmin on the hepatocytes and promoted hepatocyte proliferation. We concluded that TAFI regulates plasmin activity through its enzymatic activity whereby it reduces the plasminogen-binding capacity of the hepatocytes. The TAFI gene expression is down-regulated in hepatocyte proliferation for producing a fibrinolytic microenvironment suitable for cell growth. This is the first report on the role of TAFI in the pericellular fibrinolysis necessary for cellular proliferation. Thrombin-activatable fibrinolysis inhibitor (TAFI)3 is a 60-kDa plasma glycoprotein secreted by hepatocytes as an inactive form. Activation of TAFI is known to be mediated by thrombin (1), thrombin-thrombomodulin complex (2), or plasmin (3). Activated TAFI down-regulates fibrinolysis by removing the plasminogen-anchoring structure from fibrin. This fibrin structure contains C-terminal lysine residues, to which plasminogen binds via its lysine-binding site (4). Thus, TAFI is thought to exhibit negative regulatory activity in the binding of plasminogen to fibrin or cell surfaces.It is well known that plasminogen on fibrin or a cell surface exerts its maximum activity there, because this binding is not only a prerequisite for plasminogen activators to convert plasminogen to plasmin efficiently, but also a guarantee for the plasmin to be protected from inactivation by specific inhibitors, such as ␣2-plasmin inhibitor (5). As such, plasminogen can fulfill its roles for both thrombolysis and pericellular proteolysis, when it is located on the surface (6).It has been reported that activation of plasminogen is observed at the early stage of liver regeneration in rats and that plasmin contributes to the priming of hepatocytes for proliferation through the reorganization of extracellular matrix (ECM) components (7). The impairment of liver regeneration and abnormalities in liver repair have been observed in plasminogen-deficient mice, when they have undergone partial hepatectomy (8, 9) or been treated with CCl 4 (10). We demonstrated that the plasminogen activator/plasmin system acts to enhance the formation of hepatocyte spheroids (11) and to promote the proliferation of hepatocyt...

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Section: Thrombin-activatable Fibrinolysis Inhibitor (Tafi)mentioning

confidence: 52%

A Novel Function of Thrombin-activatable Fibrinolysis Inhibitor during Rat Liver Regeneration and in Growth-promoted Hepatocytes in Primary Culture

Okumura

Koh

Hasebe

et al. 2009

Journal of Biological Chemistry

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“…These factors are not only involved in the degradation of fibrin clot in blood vessels, but also in the patho/physiological events in the liver such as acute liver injury and ischemia-reperfusion injury of the liver [11,12]. We also reported recently that PA/plasmin system was involved in the mechanism of hepatocyte adhesion and migration during spheroid formation on PM dishes [13].…”

Section: Introductionmentioning

confidence: 94%

“…The culture medium was replaced with fresh medium every 24 h after plating. In experiments to examine the effects of tranexamic acid (Sigma-Aldrich) and anti-plasmin antibody (generated in our laboratory [13]) on the formation of spheroids, either inhibitor was added at 6 h after the plating; and the hepatocytes were cultured continuously in the presence of the inhibitor.…”

Section: Preparation Of Hepatocytes and Their Culturesmentioning

confidence: 99%

Formation of rat hepatocyte spheroids on agarose

Hasebe¹,

Okumura²,

Koh³

et al. 2005

Hepatology Research

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“…mRNAs of uPA, uPAR, and GAPDH were measured by RT-PCR, as previously described. 17) PCR was performed with specific primers, described as follows: Rat uPA primers, 5 0 -CGG AGA GAT GAA GTT TGA GGT GGA GCA GCT-3 0 (U) and 5 0 -CAC TCT GGG TCA GCA GCA CAC AGC ATT TTA-3 0 (L), were used for 25-cycle amplification of uPA cDNA (annealing at 63 C for 1 min, extension at 72 C for 1 min, and denaturation at 94 C for 1 min). Rat uPAR primers, 5 0 -GCA CCT TTG GAT GTT CCT A-3 0 (U) and 5 0 -CCA TTA CAG CAG GAG ATA GA-3 0 (L), were used for 25-cycle amplification of uPAR cDNA (annealing at 55 C for 1 min, extension at 72 C for 1 min, and denaturation at 94 C for 1 min).…”

Section: Measurement Of Pas and Mmps Activitiesmentioning

confidence: 99%

Cell Surface-Bound Plasminogen Regulates Hepatocyte Proliferation Through a uPA-Dependent Mechanism

Okumura

Seki

Ariga

2007

Bioscience, Biotechnology, and Biochemistry

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Plasminogen and plasminogen activators play important roles in liver regeneration. Previously, we found that plasminogen potentiates hepatocyte proliferation in the primary culture of rat hepatocytes. Here, we examined how exogenous plasminogen affects the downstream events leading to cell proliferation. The addition of plasminogen to hepatocytes increased urokinase-type plasminogen activator (uPA) activity, but did not affect matrix metalloproteinase (MMP)-9 or MMP-2 activities. To increase uPA activity, plasminogen was required to bind the hepatocyte surface through the lysine-binding site of plasminogen molecule, but neither uPA mRNA nor uPA receptor (uPAR) mRNA was affected by the exogenous plasminogen. In addition, treatment of hepatocytes with an uPA inhibitor, p-aminobenzamidine, inhibited the plasminogen-induced and even EGF-induced hepatocyte proliferation. These results suggest that plasminogen-related control of hepatocyte proliferation is exerted topically by producing a hyperfibrinolytic state on the cellular surface involving the activation of uPA.

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Plasminogen activator/plasmin system regulates formation of the hepatocyte spheroids

Cited by 18 publications

References 31 publications

A Novel Function of Thrombin-activatable Fibrinolysis Inhibitor during Rat Liver Regeneration and in Growth-promoted Hepatocytes in Primary Culture

A Novel Function of Thrombin-activatable Fibrinolysis Inhibitor during Rat Liver Regeneration and in Growth-promoted Hepatocytes in Primary Culture

Formation of rat hepatocyte spheroids on agarose

Cell Surface-Bound Plasminogen Regulates Hepatocyte Proliferation Through a uPA-Dependent Mechanism

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