Mast cells play a key role in Th2 cytokine-dependent asthma model through production of adhesion molecules by liberation of TNF-alpha

Mast cells are well recognized as key cells in allergic reactions, such as asthma and allergic airway diseases. However, the effects of mast cells and TNF-alpha on T-helper type 2 (Th2) cytokine-dependent asthma are not clearly understood. Therefore, an aim of this study was to investigate the role of mast cells on Th2 cytokine-dependent airway hyperresponsiveness and inflammation. We used genetically mast cell-deficient WBB6F1/J-KitW/KitW-v (W/Wv), congenic normal WBB6F1/J-Kit+/Kit+ (+/+), and mast cell-reconstituted W/Wv mouse models of allergic asthma to investigate the role of mast cells in Th2 cytokine-dependent asthma induced by ovalbumin (OVA). And we investigated whether the intratracheal injection of TNF-alpha directly induce the expression of ICAM-1 and VCAM-1 in W/Wv mice. This study, with OVA-sensitized and OVA-challenged mice, revealed the following typical histopathologic features of allergic diseases: increased inflammatory cells of the airway, airway hyperresponsiveness, and increased levels of TNF-alpha, intercellular adhesion molecule (ICAM)-1, and vascular cellular adhesion molecule (VCAM)-1. However, the histopathologic features and levels of ICAM-1 and VCAM-1 proteins in W/Wv mice after OVA challenges were significantly inhibited. Moreover, mast cell-reconstituted W/Wv mice showed restoration of histopathologic features and recovery of ICAM-1 and VCAM-1 protein levels that were similar to those found in +/+ mice. Intratracheal administration of TNF-alpha resulted in increased ICAM-1 and VCAM-1 protein levels in W/Wv mice. These results suggest that mast cells play a key role in a Th2 cytokine-dependent asthma model through production of adhesion molecules, including ICAM-1 and VCAM-1, by liberation of TNF-alpha.

A study on immunopathogenetic mechanisms of atherosclerotic process caused by chronic infection of Chlamydia pneumoniae in rats (Ratus novergicus).

AIM: this study was aimed to determine the correlations between duration of Chlamydia pneumoniae infection and the development of atherosclerotic process in white-rats' (Ratus novergicus) aorta. METHODS: this is an experimental study which examined the expression of TNFa, IL-1b, IL-8, adhesion molecule of VCAM-1 and the development of foam cells associated with atherosclerotic process in white-rats' aorta. There were 32 male rats, +/- 6 weeks of age, divided into 4 groups: control group (K) without infection, and 3 groups with infection through nasal and oral inoculation of Chlamydia pneumoniae by single dose of 5 x 105 in amount of 35 microl. The first group (P1) was preserved for 5(1/2) months period, the second group (P2) was preserved for 7(1/2) months and the third group (P3) was preserved for 9(1/2) months. At the end of study, histological slides were made from aortic tissues in order to study the development of atherosclerotic process by examining foam cells and cytokines expression of TNFa, IL-1b, IL-8 and VCAM-1. Foam cells examination was performed by Hematoxcillin-eosin staining, while indirect immunohistochemistry staining was used to examine the expression of TNFa, IL-1b, IL-8 and VCAM-1. Afterward, the amount of foam cells and cytokines expression was measured. The study result was analyzed by ANOVA. RESULTS: there was increased expression of TNFa, IL-1b, IL-8, VCAM-1and increased foam cells formation (extended atherosclerosis area) in the aortic tissues infected by Chlamydia pneumoniae (5(1/2) months, 7(1/2) months and 9(1/2) months), which was significantly different compared to the control group. The result of ANOVA revealed that the most important factor in tissue injury is foam cells development induced by VCAM-1 and IL-8 in all of phases (characterized by most abundant neutrophil infiltration). It indicated the infection caused by extracellular pathogenic agent, which established the fatty streak (acute phase) in 5(1/2) months period. In the group with 7(1/2) months infection period, TNFa also had important roles (characterized by increased monocytes and lymphocytes infiltration), indicating that there was negative-gram pathogenic agent with intracellular infection, which caused a progressive atherosclerotic process, and development of fibrosis / atherosclerotic plaque (sub acute phase). In 9(1/2) months infection period, there was large thrombus containing a lot of leukocytes in the aorta (chronic phase). CONCLUSION: based on the result of this study, it may be concluded that Chlamydia pneumoniae may cause atherosclerotic process in aorta. Extracellular infection of Chlamydia pneumoniae occurs in all of phases and intracellular infection begins in sub-acute phase. On 5(1/2) months period, fatty streak is developed (acute phase); on 7(1/2) months period, there is atherosclerotic plaque (sub acute phase); and on 9(1/2) period, there is large thrombus containing a lot of leukocytes (a progressive chronic phase).

Expression of NF-kappaB and Cytokines in Chronic Rejection of Transplanted Murine Heart

The heart transplantation-associated accelerated graft arteriosclerosis (AGAS) is one of the major causes of cardiac allograft failure. We investigated the early time-course of expresssion patterns of cytokines, transcription factor, and its inhibitor in the intraabdominally transplanted mice hearts that differed only in the D locus of class I histocompatibility antigen. The allograft hearts were harvested at 1-3, 5, 7, 14, 28, and 42 days after the transplantation, and the expressions of NF-kappaB/I-kappaB and cytokines (TNF-alpha , INF-gamma) were examined in these specimens. The expressions of TNF-alpha and INF-gamma were observed on day 1, peaking on day 5 and 7, respectively. Activated NF-kappaB (p65) expression was present on the cytoplasm and perinuclear area in the endothelial cells of coronary arteries on day 1. The peak of translocation of NF-B from cytoplasm to nucleus appeared on day 5 in the endothelial cells, myocytes, and leukocytes within the vessels, and remained elevated until day 42. The I-kappaB expression gradually increased from day 1 until day 5, but a remarkable decrease was detected on day 7. Our data suggest that the increased expressions of NF-kappaB/I-kappaB and cytokines (TNF-alpha, INF-gamma) play an important role in inducing immune responses in the donor allograft heart and hence the blockage of the expressions might be mandatory to avoid a potential graft failure.

Time-dependent expression of ICAM-1 & VCAM-1 on coronaries of the heterotopically transplanted mouse heart

To investigate the pathogenesis of accelerated graft atherosclerosis after rdiac transplantation, a genetically well-defined and reproducible animal del is required. We performed heterotopic intraabdominal heart transplantation tween the two inbred strains of mice. Forty hearts from B10.A mice were ansplanted into B10.BR mice. Recipients were sacrificed at 1, 3, 5, 7, 14, 28, d 42 days after implantation. The specimens from both donor and recipient were amined with fluorescent immunohistochemistry and the serial histopathologic anges were evaluated. In the donor hearts, ICAM-1 and VCAM-1 expressions were nimal at day 1 and they gradually increased, reaching their peaks on day 5 or and remained unchanged by day 42. However, there were very little expressions the recipients' hearts. Mean percent areas of intima in the donor coronaries vealed progressive increase by day 42. However, those in the recipients cupied consistently less than 5% of the lumen. In conclusion, we demonstrated at a heterotopic murine heart transplantation model was a useful tool to oduce transplantation coronary artery disease and that adhesion molecules on e cardiac allografts were activated very early and remained elevated at all me-points, nonetheless the arterial lesion was detected after day 28 and its ogression was accelerated thereafter.

Effects of mixed leukocyte reaction, hydrocortisone and cyclosporine on expression of leukocyte adhesion molecules by endothelial and mesangial cells

We investigated the effects of mixed leukocyte reaction (MLR), hydrocortisone (HC) and cyclosporine A (CsA) on the expression of leukocyte adhesion molecules on the mesangial (MC) and endothelial cells (EnC). Cell surface enzyme immunoassay showed that INFnu, IL-1beta, or TNF alpha stimulated expression of ICAM-1, or VCAM-1 on MC after 24 hours. Flow cytometric analysis demonstrated that MLR supernatant induced a marked increase in mean fluorescence of or % of cells highly expressing intercellular adhesion molecule(ICAM)-1 or vascular cell adhesion molecule (VCAM)-1 on both cells after 24 hours (p<0.001). HC treatment(300 ng/ml) during MLR effectively inhibited MLR-induced upregulation of ICAM-1 and VCAM-1 on both cells (p<0.005). When MLR supernatant with HC was added to adhesion molecule assay, there was no inhibitory effect of HC on VCAM-1. CsA treatment (500 ng/ml) during MLR caused a modest decrease in upregulation of VCAM-1 on EnC (p<0.05), but had no effects on ICAM-1 on both cells. CsA directly decreased expression of VCAM-1 on MC. In conclusion, alloreactive lymphocytes and monocytes upregulate the expression of VCAM-1 and ICAM-1 on target cells probably by the mediation of cytokines. HC effectively prevents MLR-induced upregulation of VCAM-1 and ICAM-1. CsA does not increase the expression of VCAM-1 and ICAM-1.

Effects of mixed leukocyte reaction, hydrocortisone and cyclosporine on expression of leukocyte adhesion molecules by endothelial and mesangial cells

We investigated the effects of mixed leukocyte reaction (MLR), hydrocortisone (HC) and cyclosporine A (CsA) on the expression of leukocyte adhesion molecules on the mesangial (MC) and endothelial cells (EnC). Cell surface enzyme immunoassay showed that INFnu, IL-1beta, or TNF alpha stimulated expression of ICAM-1, or VCAM-1 on MC after 24 hours. Flow cytometric analysis demonstrated that MLR supernatant induced a marked increase in mean fluorescence of or % of cells highly expressing intercellular adhesion molecule(ICAM)-1 or vascular cell adhesion molecule (VCAM)-1 on both cells after 24 hours (p<0.001). HC treatment(300 ng/ml) during MLR effectively inhibited MLR-induced upregulation of ICAM-1 and VCAM-1 on both cells (p<0.005). When MLR supernatant with HC was added to adhesion molecule assay, there was no inhibitory effect of HC on VCAM-1. CsA treatment (500 ng/ml) during MLR caused a modest decrease in upregulation of VCAM-1 on EnC (p<0.05), but had no effects on ICAM-1 on both cells. CsA directly decreased expression of VCAM-1 on MC. In conclusion, alloreactive lymphocytes and monocytes upregulate the expression of VCAM-1 and ICAM-1 on target cells probably by the mediation of cytokines. HC effectively prevents MLR-induced upregulation of VCAM-1 and ICAM-1. CsA does not increase the expression of VCAM-1 and ICAM-1.