ABSTRACT
Intestinal?barrier?act?as?the?crucial?defender?against?pathogen?invasion,?and?is?indispensable?in?maintaining?tissue?homeostasis?both?locally?and?systemically.?Severe?disease?can?lead?to?impaired?intestinal?barrier.?In?addition?to?cause?a?variety?of?gastrointestinal?diseases,?intestinal?barrier?damage?can?also?worsen?the?disease?progression?in?critically?ill?patients.?Innate?lymphoid?cells?(ILCs)?is?a?group?of?newly?defined?innate?immune?cells?which?have?some?characteristics?as?adaptive?immune?cells.?Group?3?innate?lymphoid?cells?(ILC3),?which?mainly?reside?at?gut?associate?mucosal?tissue,?have?been?reported?to?play?a?critical?role?in?maintaining?intestinal?barrier?function.?After?a?brief?introduction?about?its?origination?and?classification,?we?will?focus?on?function?of?ILC3?physiologically?and?pathologically,?and?provide?a?new?theoretical?basis?for?maintaining?intestinal?barrier?function?under?pathological?conditions?in??this?review.
ABSTRACT
Objective To investigate the role and mechanism of ulinastatin on the hyper-permeability of vascular endothelial cell induced by matrix metalloproteinase-9 (MMP-9). Methods Human umbilical vein endothelial cells (HUVEC) were cultured in vitro to establish a complete monolayer vascular endothelial cell model. The monolayer vascular endothelial cells were randomly divided into three groups: blank control group [phosphate buffered saline (PBS) added], MMP-9 model group (1 mg/L MMP-9 added) and ulinastatin group (1 mg/L MMP-9 and 1 000 kU/L ulinastatin added). The permeability of monolayer vascular endothelial cells was measured by fluorescein isothiocyanate (FITC)-labeled dextran (FD40) leaking method; the soluble vascular endothelial cells calcium dependent adherin (VE-cadherin) concentration in culture solution was determined by enzyme linked immunosorbent assay (ELISA);the protein expression levels of zonular occlusion protein-1 or tight junction (ZO-1), VE-cadherin, claudin-5 were detected by Western Blot and immunofluorescence methods. Results Compared with the blank control group, the permeability of vascular endothelial cells in MMP-9 model group was significantly increased [(cm2/h, ×10-2):3.35±0.56 vs. 0.94±0.06, P < 0.05]; the concentrations of soluble VE-cadherin in the Transwell upper and lower chambers were increased significantly [upper chamber (μg/L): 5.02±0.40 vs. 3.83±0.42, lower chamber (μg/L):4.92±1.05 vs. 3.24±1.24, both P < 0.05]; the protein expression levels of ZO-1, VE-cadherin and claudin-5 were significantly decreased [ZO-1/β-actin: 0.152±0.067 vs. 0.262±0.090, VE-cadherin/β-actin: 0.137±0.048 vs. 0.246±0.094, claudin-5/β-actin: 0.148±0.062 vs. 0.336±0.119, all P < 0.05], and obvious rupture sites appeared in their fluorescent patterns, and fluorescent particles were significantly reduced; compared with MMP-9 model group, the permeability of vascular endothelial cells in ulinastatin group was significantly decreased [(cm2/h, ×10-2): 1.80±0.34 vs. 3.35±0.56, P < 0.05]; the soluble VE-cadherin concentrations were significantly reduced in upper and lower chambers than those in the MMP-9 model group [upper chamber (μg/L): 4.41±0.37 vs. 5.02±0.40, lower chamber (μg/L):3.85±1.04 vs. 4.92±1.05, both P < 0.05], the expressions of endothelial junction protein were significantly increased in ulinastatin group (ZO-1/β-actin: 0.229±0.097 vs. 0.152±0.067, VE-cadherin/β-actin: 0.236±0.089 vs. 0.137±0.048, claudin-5/β-actin: 0.262±0.101 vs. 0.148±0.062, all P < 0.05], and the continuity of their fluorescent patterns and fluorescent particles were both increased. Conclusion The in vitro experiment showed that the hyper-permeability of vascular endothelial cells induced by MMP-9 can be attenuated by ulinastatin through decreasing the destruction of VE-cadherin and maintaining the protein expression levels of ZO-1, VE-cadherin and claudin-5 in vascular endothelial cells.