T cell lymphokines modulate bFGF-induced smooth muscle cell fibrinolysis and migration

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

Glutamatergic Receptor Activation in the Commisural Nucleus Tractus Solitarii (cNTS) Mediates Brain Glucose Retention (BGR) Response to Anoxic Carotid Chemoreceptor (CChr) Stimulation in Rats

Glutamate, released from central terminals of glossopharyngeal nerve, is a major excitatory neurotransmitter of commissural nucleus tractus solitarii (cNTS) afferent terminals, and brain derived neurotrophic factor (BDNF) has been shown to attenuate glutamatergic AMPA currents in NTS neurons. To test the hypothesis that AMPA contributes to glucose regulation in vivo modulating the hyperglycemic reflex with brain glucose retention (BGR), we microinjected AMPA and NBQX (AMPA antagonist) into the cNTS before carotid chemoreceptor stimulation in anesthetized normal Wistar rats, while hyperglycemic reflex an brain glucose retention (BGR) were analyzed. To investigate the underlying mechanisms, GluR2/3 receptor and c-Fos protein expressions in cNTS neurons were determined. We showed that AMPA in the cNTS before CChr stimulation inhibited BGR observed in aCSF group. In contrast, NBQX in similar conditions, did not modify the effects on glucose variables observed in aCSF control group. These experiments suggest that glutamatergic pathways, via AMPA receptors, in the cNTS may play a role in glucose homeostasis.

Expression of a Secreted Fibroblast Growth Factor Binding Protein-1 (FGFBP1) in Angioproliferative Kaposi Sarcoma

OBJECTIVE

Kaposi's sarcoma (KS) is an angioproliferative disease frequently seen in patients with the acquired immunodeficiency syndrome (AIDS). Previous studies suggest that the HIV-1 protein Tat and Fibroblast Growth Factor 2 (FGF-2) have synergistic angiogenic effects in AIDS-KS tumors. However, the mechanisms by which FGF-2 is released and activated in KS tumors are not clearly defined. We carried out this study to determine whether an FGF-binding protein (FGFBP1 or BP1) that enhances the angiogenic activity of FGF-2 is expressed in AIDS-KS tumors, and to define whether BP1, FGF-2, and HIV-Tat protein-protein interactions could play a potential clinically role in the pathogenesis of AIDS-KS.

METHODS

BP1 was localized in AIDS-KS lesions by immunohistochemistry and in situ hybridization studies. The binding of radiolabeled FGF-2 to His-tagged BP1 or the FGF-receptor 1 was assessed in the presence and absence of HIV-Tat and other viral proteins. Mice carrying tetracycline-regulated BP1 transgene mice were used to determine whether activation of BP1 during wound healing induces KS-like lesions.

RESULTS

BP1 expression was detected in AIDS-KS tumor keratinocytes, spindle cells, and infiltrating mononuclear cells. In addition, HIV-Tat competed for the binding of FGF-2 to immobilized BP1, but does not affect the interactions of FGF-2 with its high affinity receptor (FGFR-1). In contrast, two other HIV-proteins, Nef and gp120, did not affect the binding of FGF-2 to BP1 or to FGFR-1. Finally, up-regulation of BP1 expression in tetracycline-regulated -conditional BP1 transgenic mice subjected to skin wounds, induced KS-like skin lesions.

CONCLUSION

Taking into consideration the results of previous studies showing that both HIV-Tat and BP1 enhance the mitogenic and angiogenic activity of locally-stored FGF-2, both in vitro and in vivo, our findings suggest a novel mechanism by which the release and activity of FGFs can be modulated in AIDS-KS tumors by HIV-Tat as well as BP1.

The interaction between low glucose and hypoxia in the in vitro, rat carotid body

A role for the carotid body (CB) in systemic glycaemic control is yet to be fully characterised. Observations made on fasted, anaesthetised cats, rats and dogs in vivo showed that intra-arterial injection of sodium cyanide into the carotid sinus region immediately increased carotid sinus nerve (CSN) discharge frequency and elicited a subsequent significant increase in the systemic arterial glucose concentration, within 2-8 min of drug administration (Alvarez-Buylla and Alvarez-Buylla 1988). These responses were abolished in animals in which both CSNs had been surgically sectioned, demonstrating that the increased arterial glucose concentration detected following CB stimulation was dependent on CSN input into the NTS. Although not directly tested by these authors, it was proposed that low plasma glucose directly stimulated the CB, as the increase in CSN discharge frequency elicited with NaCN was attenuated by direct injection of a hyperglycaemic solution into the common carotid artery (Alvarez-Buylla and Alvarez-Buylla 1988; Alvarez-Buylla et al. 1997). Additionally, in dogs with bilateral CB resection (CBR), the rate of exogenous glucose infusion required to maintain a fixed hypoglycaemic level was significantly higher, whilst the endogenous hepatic glucose production was significantly lower, compared to control (CSN intact) animals (Koyama et al. 2000). These results further suggested a dependence on CB stimulation for the maintenance of a physiologically normal plasma glucose concentration, but again no direct measure of CB response to hypoglycaemia had been made.

Elevated plasma levels of interleukin-2 and soluble IL-2 receptor in ischemic heart disease

BACKGROUND

T-lymphocytes are present in significant numbers in the atherosclerotic plaque, but their role in the progression and pathogenesis of coronary syndromes remains poorly understood.

HYPOTHESIS

We sought to determine the relationship between T-lymphocyte activation and ischemic heart disease by measuring plasma levels of cytokines related to T-lymphocyte function in patients with stable and unstable angina.

METHODS

Plasma levels of interleukin-2 (IL-2) and soluble IL-2 receptor (sIL-2R) were measured in 105 patients: 66 with stable angina, 24 with unstable angina, and 15 healthy controls. Patients who presented to the cardiac catheterization laboratory with unstable or stable anginal syndromes for coronary angiography or percutaneous coronary intervention enrolled in the study.

RESULTS

Mean levels of IL-2 were significantly higher in patients with stable angina than in those with unstable angina. The differences between stable angina and control groups, or between unstable angina and control groups, were not statistically significant. Mean levels of slL-2R were significantly higher in patients with stable angina than in either patients with unstable angina or control patients.

CONCLUSIONS

Levels of IL-2 and sIL-2 receptor are significantly elevated in patients with stable angina, but not in patients with unstable angina. The contribution of T-lymphocytes to the development of both stable and unstable angina requires further investigation.

Increased expression of lymphocyte-derived cytokines in benign hyperplastic prostate tissue, identification of the producing cell types, and effect of differentially expressed cytokines on stromal cell proliferation

BACKGROUND

Benign prostatic hyperplasia (BPH) frequently exhibit infiltration of CD4 (+)/CD45RO (+) memory-T-lymphocytes. Expression and impact of lymphocyte-derived growth factors on prostatic stromal cell (PSC) growth were investigated. METHODS; Lymphokine synthesis in normal prostate tissues (n = 3), BPH-tissues (n = 13), BPH-derived T-cells (n = 6), BPH-derived epithelial cells (BPH-EC) (n = 5), normal prostate-derived (n = 3) and BPH-derived stromal cell lines (BPH-SC) (n = 6), and prostate cancer (CaP) lines (n = 3) was analyzed by RT-PCR and Southern-blotting. The effect of interleukin (IL)-2, -4, -7, and interferon-gamma (IFN-gamma) on normal and BPH-SC growth was investigated by (3)H-thymidine incorporation assays.

RESULTS

All BPH-tissues and, to a lesser degree, normal prostates, expressed significant amounts of IFN-gamma mRNA. However, only BPH-tissues contained IL-2 and IL-4 mRNA (ratio: 10:13). BPH-T-cell lines were heterogeneous in composition and expressed significant amounts of IFN-gamma, IL-2, and IL-4 mRNA. Low level expression of these lymphokines was also observed in BPH-EC, CaP lines, and PSC lines. IL-2, -7 and IFN-gamma stimulated the proliferation of BPH-PSC lines but not that of normal PSC, while IL-4 inhibited BPH-PSC growth.

CONCLUSIONS

Chronic inflammation may induce an increased growth pattern of fibromuscular tissue in BPH similar to that of wound healing.

Induction of plasminogen activator inhibitor-1 in endothelial cells by basic fibroblast growth factor and its modulation by fibric acid

Plasminogen activator inhibitor-1 (PAI-1) inhibits fibrinolysis and proteolysis. Basic fibroblast growth factor (bFGF) stimulates angiogenesis, which requires regional proteolysis. Because modulation of vasculopathy requires tight control of proteolysis, effects of bFGF on PAI-1 expression in endothelial cells (ECs) were characterized. bFGF increased PAI-1 mRNA and accumulation of PAI-1 protein in conditioned media in human umbilical vein ECs. The bFGF-mediated increase in PAI-1 mRNA was attenuated by inhibition of extracellular signal-regulated kinase kinase in human ECV304 cells. The rate of decrease in PAI-1 mRNA after actinomycin D treatment was not affected by bFGF. Transient transfection assays of the human PAI-1 promoter-luciferase construct demonstrated that bFGF-induced PAI-1 transcription was dependent on the elements within the -313 to -260 bp relative to the transcription start site. This region contains an E26 transformation specific 1 (Ets-1)-like site. Electrophoretic mobility shift assay showed that bFGF increased nuclear translocation or DNA binding of the Ets-1-like transcription factor to the PAI-1 promoter. Nucleotide substitution to disrupt the Ets-1-like site reduced bFGF-stimulated promoter activity. Fenofibric acid, an agonist ligand for the peroxisome proliferator-activated receptor-alpha, inhibited basal and bFGF-stimulated PAI-1 expression. By inducing PAI-1 expression from ECs, bFGF may control proteolysis and fibrinolysis in vessel walls.

Defibrinogenating effect of batroxobin (Defibrase®) in rats and inhibition of migration of human vascular smooth muscle cells by the plasma of batroxobin-treated rats in vitro

The defibrinogenating effect of batroxobin (Defibrase) in male Wistar rats and the inhibitory effects of the plasma of batroxobin-treated rats on the migration of human vascular smooth muscle cells (SMCs) were investigated in vitro. At 1 h after a single intravenous injection of 3.0, 10.0 or 30.0 BU/kg batroxobin (ten rats in each group), the fibrinogen levels in the plasma of the rats decreased to 88.3, 66.2 and 16.5%, respectively, of that in the plasma of control saline-treated rats (261.0+/-26.7 mg/dl). When the plasma from the batroxobin-treated rats was added to Dulbecco's modified Eagle's medium at a concentration of 0.2% for a vascular SMC migration assay and incubated in a modified Boyden's chamber system at 37 degrees C for 24 h, significant inhibitory effects on vascular SMC migration were observed in the 10.0 (P<0.05) and 30.0 BU/kg (P<0.01) batroxobin-treated rats. The plasma of batroxobin-treated rats as well as standard rat fibrinogen induced vascular SMC migration in a fibrinogen content-dependent manner except the plasma of the 30.0 BU/kg batroxobin-treated rats. Moreover, the rat serum (0.1 approximately 5.0%) did not show any activity on vascular SMC migration in the present experimental system. These results indicate that the plasma fibrinogen significantly influences vascular SMC migration, and that the inhibitory effect of the plasma of batroxobin-treated rats on vascular SMC migration is related to the defibrinogenating action of batroxobin in vivo.

Requirement of aquaporin-1 for NaCl-driven water transport across descending vasa recta

Deletion of AQP1 in mice results in diminished urinary concentrating ability, possibly related to reduced NaCl- and urea gradient-driven water transport across the outer medullary descending vasa recta (OMDVR). To quantify the role of AQP1 in OMDVR water transport, we measured osmotically driven water permeability in vitro in microperfused OMDVR from wild-type, AQP1 heterozygous, and AQP1 knockout mice. OMDVR diameters in AQP1(-/-) mice were 1.9-fold greater than in AQP1(+/+) mice. Osmotic water permeability (P(f)) in response to a 200 mM NaCl gradient (bath > lumen) was reduced about 2-fold in AQP1(+/-) mice and by more than 50-fold in AQP1(-/-) mice. P(f) increased from 1015 to 2527 microm/s in AQP1(+/+) mice and from 22 to 1104 microm/s in AQP1(-/-) mice when a raffinose rather than an NaCl gradient was used. This information, together with p-chloromercuribenzenesulfonate inhibition measurements, suggests that nearly all NaCl-driven water transport occurs by a transcellular route through AQP1, whereas raffinose-driven water transport also involves a parallel, AQP1-independent, mercurial-insensitive pathway. Interestingly, urea was also able to drive water movement across the AQP1-independent pathway. Diffusional permeabilities to small hydrophilic solutes were comparable in AQP1(+/+) and AQP1(-/-) mice but higher than those previously measured in rats. In a mathematical model of the medullary microcirculation, deletion of AQP1 resulted in diminished concentrating ability due to enhancement of medullary blood flow, partially accounting for the observed urine-concentrating defect.

Lung fluid transport in aquaporin-1 and aquaporin-4 knockout mice

The mammalian lung expresses water channel aquaporin-1 (AQP1) in microvascular endothelia and aquaporin-4 (AQP4) in airway epithelia. To test whether these water channels facilitate fluid movement between airspace, interstitial, and capillary compartments, we measured passive and active fluid transport in AQP1 and AQP4 knockout mice. Airspace-capillary osmotic water permeability (Pf) was measured in isolated perfused lungs by a pleural surface fluorescence method. Pf was remarkably reduced in AQP1 (-/-) mice (measured in cm/s x 0.001, SE, n = 5-10: 17 +/- 2 [+/+]; 6.6 +/- 0.6 AQP1 [+/-]; 1.7 +/- 0.3 AQP1 [-/-]; 12 +/- 1 AQP4 [-/-]). Microvascular endothelial water permeability, measured by a related pleural surface fluorescence method in which the airspace was filled with inert perfluorocarbon, was reduced more than 10-fold in AQP1 (-/-) vs. (+/+) mice. Hydrostatically induced lung interstitial and alveolar edema was measured by a gravimetric method and by direct measurement of extravascular lung water. Both approaches indicated a more than twofold reduction in lung water accumulation in AQP1 (-/-) vs. (+/+) mice in response to a 5- to 10-cm H2O increase in pulmonary artery pressure for five minutes. Active, near-isosmolar alveolar fluid absorption (Jv) was measured in in situ perfused lungs using 125I-albumin as an airspace fluid volume marker. Jv (measured in percent fluid uptake at 30 min, n = 5) in (+/+) mice was 6.0 +/- 0.6 (37 degrees C), increased to 16 +/- 1 by beta-agonists, and inhibited to less than 2.0 by amiloride, ouabain, or cooling to 23 degrees C. Jv (with isoproterenol) was not affected by aquaporin deletion (18.9 +/- 2.2 [+/+]; 16.4 +/- 1.5 AQP1 [-/-]; 16.3 +/- 1.7 AQP4 [-/-]). These results indicate that osmotically driven water transport across microvessels in adult lung occurs by a transcellular route through AQP1 water channels and that the microvascular endothelium is a significant barrier for airspace-capillary osmotic water transport. AQP1 facilitates hydrostatically driven lung edema but is not required for active near-isosmolar absorption of alveolar fluid.