ABSTRACT
Effective clearance of inflammatory cells is required for resolution of inflammation. Here, we show in vivo evidence that apoptosis and reverse transendothelial migration (rTEM) are important mechanisms in eliminating neutrophils and facilitating recovery following ischemia/reperfusion injury (IRI) of the kidney. The clearance of neutrophils was delayed in the Bax knockout (KO)BM → wild-type (WT) chimera in which bone marrow derived cells are partially resistant to apoptosis, compared to WTBM → WT mice. These mice also showed delayed functional, histological recovery, increased tissue cytokines, and accelerated fibrosis. The circulating intercellular adhesion molecule-1 (ICAM-1)+ Gr-1+ neutrophils displaying rTEM phenotype increased during the recovery phase and blockade of junctional adhesion molecule-C (JAM-C), a negative regulator of rTEM, resulted in an increase in circulating ICAM-1+ neutrophils, faster resolution of inflammation and recovery. The presence of Tamm-Horsfall protein (THP) in circulating ICAM-1+ neutrophils could suggest that they are derived from injured kidneys. In conclusion, we suggest that apoptosis and rTEM are critically involved in the clearance mechanisms of neutrophils during the recovery phase of IRI.
Subject(s)
Animals , Mice , Acute Kidney Injury , Apoptosis , Bone Marrow , Chimera , Cytokines , Fibrosis , Inflammation , Intercellular Adhesion Molecule-1 , Kidney , Neutrophils , Phenotype , Transendothelial and Transepithelial Migration , UromodulinABSTRACT
Objective To investigate the function of chemokine receptor 5（CCR5）in human brain microvascular endothelial cells（HBMEC）during T lymphocytes transendothelial migration induced by amyloid beta（Aβ）.Methods The in vitro model of blood-brain barrier was established with cultured HBMEC monolayer.The ability of T lymphocytes transendothelial migration induced by Aβ was analyzed by Transwell and Millicell-ERS endothelia volt-ohmmeter.Results Aβ could promote T lymphocytes to migrate through the HBMEC monolayer.Over-expression of CCR5 in HBMEC promoted T lymphocytes to migrate through HBMEC monolayer.Expression of CCR5 mutant in HBMEC inhibited the transendothelial migration of T lymphocytes.Conclusion CCR5 of HBMEC is involved in T lymphocytes transendothelial migration induced by Aβ.
ABSTRACT
Objective:To investigate whether VLA-5 and VLA-6 are involved in facilitating en-dothelium-oriented transmigration of hematopoietic stem/progenitor cells. Methods:Purified hu-man CD34+ cells were subject to ex vivo transmigration assay and blocking experiments throughtranswell filter inserts coated with human umbilical vein endothelial cells (HUVECs). Four-colorfluorescence-activated cell sorting (FACS) analysis was applied to detect the expression profilesof adhesion molecules and chemokine receptor CXCR-4 on CD34bright cells. Results:Stromal cell-derived factor (SDF)-1-induced transmigrations of both mobilized peripheral blood (mPB)-(56.6±20. 1)% and bone marrow (BM)- (15. 6±1. 8)% derived CD34+ cells were significantlyfacilitated through HUVECs-coated transwell filter insters compared with noncoated ones, whichwere efficiently blocked by preincubation of CD34+ cells with neutralizing antibodies to VLA-5,or VLA-6, or both of them; meanwhile the proportions of migrating CD34+ cells through bothHUVECs-coated and noncoated transwell filter inserts in BM were significantly lower than thosein mPB; the different percentages of migrating CD34+ cells between in mPB and BM were corre-lated with their variable expressions of VLA-5 and VLA-6, but not for VLA-4 or chemokine re-ceptor CXCR-4. Conclusion:Facilitating HS/PCs transmigrations through HUVECs are involvedin both VLA-5 and VLA-6.
ABSTRACT
BACKGROUND: Rhinovirus infection of the airways results in increased permeability of the airway vascular endothelium with the influx of plasma proteins, including lipids such as LDL. In vitro studies on the effect of oxLDL on leukocytes has shown many proinflammatory effects on multiple leukocytes. We hypothesized that oxLDL is one mechanism for recruiting granulocytes to the airways during a RV infection. Therefore, chemotaxis and transendothelial migration, in response to nLDL, was determined for these granulocytes. METHODS: nLDL was oxidized with 5mM Cu2SO4 for 20-24 hours. 3-5×10(5) cells were loaded into the Transwell filter while the chemotatic agonists were placed in the lower well for chemotaxis. Confluent monolayers on HPMEC were grown on Transwell filters for transendothelial migration. The filters were washed and eosinophils and neutrophils loaded on to the filter with the chemotatic agonist was were placed in the lower well. The wells were incubated for 3 hours. The number of migrating cells was counted on a hemocytometer. RESULTS: OxLDL, but not nLDL, is chemotatic for eosinophils and neutrophils. The level of granulocytes chemotaxis was dependent on both the concentration of LDL and its degree of oxidation. OxLDL stimulates eosinophil and neutrophils migration across HPMEC monolayers (±IL-1β preactivation) in a dose dependent manner. CONCLUSION: Increased vascular permeability during a RV infection may lead to the influx and oxidation of LDL. The resulting oxLDL. is one possible mechanism for the recruitment of neutrophils and eosinophils to the airway interstitial matrix. Once in the airways, granulocytes can further interact with oxLDL to promote airway inflammation.