Thrombin and PAR-1-AP Increase Proinflammatory Cytokine Expression in C6 Cells1

Fan, Yongyi; Zhang, Weizhen; Mulholland, Michael W.

doi:10.1016/j.jss.2005.07.041

Cited by 44 publications

(32 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A possible explanation for the increase in paracellular solute permeability seen with exposure to astrocyte-conditioned media is that C6 cells, a tumor cell line, could be secreting a tumor-related factor that opens the barrier, as seen in vivo [8,35,52]. Tumor necrosis factor-α (TNF-α), for example, increases BBB permeability [42,86], and is secreted by C6 cells [39]. Release of this cytokine into the astrocyte-conditioned media could account for the increase in monolayer permeability seen in cells exposed to this media.…”

Section: Discussionmentioning

confidence: 99%

Tight junction protein expression and barrier properties of immortalized mouse brain microvessel endothelial cells

2007

View full text Add to dashboard Cite

Understanding the molecular and biochemical mechanisms regulating the blood-brain barrier is aided by in vitro model systems. Many studies have used primary cultures of brain microvessel endothelial cells for this purpose. However, primary cultures limit the generation of material for molecular and biochemical assays since cells grow slowly, are prone to contamination by other neurovascular unit cells, and lose blood-brain barrier characteristics when passaged. To address these issues, immortalized cell lines have been generated. In these studies, we assessed the suitability of the immortalized mouse brain endothelial cell line, bEnd3, as a blood-brain barrier model. RT-PCR and immunofluorescence indicated expression of multiple tight junction proteins. bEnd3 cells formed barriers to radiolabeled sucrose, and responded like primary cultures to disrupting stimuli. Exposing cells to serum-free media on their basolateral side significantly decreased paracellular permeability; astrocyte-conditioned media did not enhance barrier properties. The serum-free media-induced decrease in permeability was correlated with an increase in claudin-5 and zonula occludens-1 immunofluorescence at cell-cell contracts. We conclude that bEnd3 cells are an attractive candidate as a model of the blood-brain barrier due to their rapid growth, maintenance of blood-brain barrier characteristics over repeated passages, formation of functional barriers and amenability to numerous molecular interventions.

show abstract

Section: Discussionmentioning

confidence: 99%

Tight junction protein expression and barrier properties of immortalized mouse brain microvessel endothelial cells

2007

View full text Add to dashboard Cite

show abstract

“…In contrast, L8W markedly suppressed IL-6, IL-18, and renal ACE-1, all markers previously associated with renal dysfunction and protection with APC. 12 Of interest, thrombin is a potent inducer of IL-6 via activation of PAR-1, [35][36][37] suggesting that the effect of L8W is by reducing thrombin and thus thrombin-mediated PAR-1 activation. The lack of an effect of L8W on the hypotensive response is consistent with studies by Isobe et al showing that inhibition of thrombin generation by active-site-inhibited factor Xa could not alter LPS-induced hypotension in an rat endotoxin model.…”

Section: Discussionmentioning

confidence: 99%

“…To further explore the potential role of thrombin inhibition via L8W, we examined other mediators known to play a role in renal microvascular function during endotoxemia, including IL-6 and thrombospondin-1 (TSP-1), which are both induced by PAR-1 induction by thrombin, [35][36][37][38] and IL-18. Activation of these mediators in AKI has been associated with modulation of renal vascular inflammation and tone.…”

Section: Mation (mentioning

confidence: 99%

Distinct Functions of Activated Protein C Differentially Attenuate Acute Kidney Injury

Gupta

Gerlitz

Richardson

et al. 2009

Journal of the American Society of Nephrology

View full text Add to dashboard Cite

Administration of activated protein C (APC) protects from renal dysfunction, but the underlying mechanism is unknown. APC exerts both antithrombotic and cytoprotective properties, the latter via modulation of protease-activated receptor-1 (PAR-1) signaling. We generated APC variants to study the relative importance of the two functions of APC in a model of LPS-induced renal microvascular dysfunction. Compared with wild-type APC, the K193E variant exhibited impaired anticoagulant activity but retained the ability to mediate PAR-1-dependent signaling. In contrast, the L8W variant retained anticoagulant activity but lost its ability to modulate PAR-1. By administering wild-type APC or these mutants in a rat model of LPS-induced injury, we found that the PAR-1 agonism, but not the anticoagulant function of APC, reversed LPS-induced systemic hypotension. In contrast, both functions of APC played a role in reversing LPS-induced decreases in renal blood flow and volume, although the effects on PAR-1-dependent signaling were more potent. Regarding potential mechanisms for these findings, APC-mediated PAR-1 agonism suppressed LPS-induced increases in the vasoactive peptide adrenomedullin and infiltration of iNOS-positive leukocytes into renal tissue. However, the anticoagulant function of APC was responsible for suppressing LPS-induced stimulation of the proinflammatory mediators ACE-1, IL-6, and IL-18, perhaps accounting for its ability to modulate renal hemodynamics. Both variants reduced active caspase-3 and abrogated LPS-induced renal dysfunction and pathology. We conclude that although PAR-1 agonism is solely responsible for APC-mediated improvement in systemic hemodynamics, both functions of APC play distinct roles in attenuating the response to injury in the kidney. 20: 267-277, 200920: 267-277, . doi: 10.1681 Acute kidney injury (AKI) leading to renal failure is a devastating disorder, 1 with a prevalence varying from 30 to 50% in the intensive care unit. 2 AKI during sepsis results in significant morbidity, and is an independent risk factor for mortality. 3,4 In patients with severe sepsis or shock, the reported incidence ranges from 23 to 51% 5-7 with mortality as high as 70% versus 45% among patients with AKI alone. 1,8 The pathogenesis of AKI during sepsis involves hemodynamic alterations along with microvascular impairment. 4 Although many factors change during sepsis, suppression of the plasma serine protease, protein C (PC), has been shown to be predictive of early death in sepsis models, 9 and clinically has been associated with early death resulting from refractory shock and multiple organ failure in severe sepsis. 10 Moreover, low levels of PC have been J Am Soc Nephrol

show abstract

“…Protein expression level of PAR-1 in the skin, small intestine, liver of allogeneic HSCT mice (lanes 2, 6, and 8) was significantly higher than that (lanes 1, 5, 7) of the control (P < 0.01), but not in the stomach, lung, kidney. Enhanced Protein expression of PAR-2 of small intestine, liver (lanes 6,8) was also seen in allogeneic HSCT mice (P < 0.05). Lanes 1,3,5,7,9,11 represent the skin, stomach, small intestine, liver, lung, kidney of syngeneic HSCT mice; lanes 2, 4, 6, 8, 10, 12 represented the skin, stomach, small intestine, liver, lung, kidney of allogeneic HSCT mice.…”

Section: Discussionmentioning

confidence: 87%

“…PAR-1, 2 have been found to be involved in a variety of physiological and pathophysiological activities, including platelet aggregation, relaxation/contraction of vascular and airway smooth muscle, nerve generation, inflammation and immune responses [5][6][7]. The activation of PAR-1, 2 can enhance the gene expression and production of proinflammatory cytokines such as TNF-α, IL-1, IL-6 [8]. Recent findings have demonstrated PARs are not only degradative enzymes, but also important signaling molecules involved in inflammation and immunology [9,10].…”

Section: Introductionmentioning

confidence: 99%

Gene and protein expression of proteinase-activated receptor-1, 2 in a murine model of acute graft vs host disease

Zhang

et al. 2009

Front. Med. China

View full text Add to dashboard Cite

Proteinase-activated receptors (PARs) are a novel subclass of seven transmembrane-spanning, G protein-coupled receptors. PAR-1 and PAR-2 are widely expressed in a variety of cells and are found to be involved in many physiological and pathological processes including inflammation and immune response. However, little is known about the function of PAR-1, 2 in acute graft vs host disease (GVHD). In the present study, we first detected the expression of PAR-1, 2 protein and mRNA in a murine model of acute GVHD using the methods of immunohistochemistry, Western blot and quantitative real-time polymerase chain reaction (PCR). Syngeneic hematopoietic stem cell transplantation (HSCT) mice served as controls. The relative gene expression level of PAR-1 was significantly increased in the skin, liver, small intestine of allogeneic HSCT mice (in skin: 0.039 AE 0.013 vs 0.008 AE 0.002 of controls, P = 0.009; in liver: 0.165 AE 0.006 vs 0.017 AE 0.006 of controls, P = 0.004; in small intestine: 0.215 AE 0.009 vs 0.016 AE 0.002 of controls, P = 0.003), but not in the stomach, lung and kidney of allogeneic HSCT mice (P > 0.05). PAR-2 mRNA expression in the liver and small intestine of allogeneic HSCT mice (in liver: 0.010 AE 0.002 vs 0.003 AE 0.001 of controls, P = 0.008; in small intestine: 0.006 AE 0.001 vs 0.003 AE 0.001 of controls, P = 0.024) was increased significantly, but PAR-2 mRNA expression in the other organs (P > 0.05) was not found to be significantly elevated. PAR-1, 2 protein expression was in accordance with the mRNA expression, as shown by Western blot. Using immunohistochemistry the present study demonstrated that there was strong PAR-1, 2 immunoreactivity in the epithelial cell and vascular endothelial cell of target organs of acute GVHD. Our findings of markedly increased expression of PAR-1, 2 in target organs of acute GVHD suggest that PAR-1 and PAR-2 may play an important role in the pathogenesis of acute GVHD.

show abstract

Thrombin and PAR-1-AP Increase Proinflammatory Cytokine Expression in C6 Cells1

Cited by 44 publications

References 22 publications

Tight junction protein expression and barrier properties of immortalized mouse brain microvessel endothelial cells

Tight junction protein expression and barrier properties of immortalized mouse brain microvessel endothelial cells

Distinct Functions of Activated Protein C Differentially Attenuate Acute Kidney Injury

Gene and protein expression of proteinase-activated receptor-1, 2 in a murine model of acute graft vs host disease

Contact Info

Product

Resources

About