Dioscorin protects tight junction protein expression in A549 human airway epithelium cells from dust mite damage.
OBJECTIVE
In addition to being an allergen, the trypsin activity of dust mite extract also destroys the tight junctions of bronchial epithelium. Such damage can lead to airway leakage, which increases airway exposure to allergens, irritants, and other pathogens. Dioscorin, the storage protein of yam, demonstrates anti-trypsin activity, as well as other potential anti-inflammatory effects. This study investigated the protective role of dioscorin for tight junctions.


METHODS
The immunofluorescence stains of zonula occludens (ZO-1), E-cadherin (EC) and desmoplakin (DP) proteins were compared. A cultured A549 cell line was used as a control and A549 cells were incubated with mite extract 100 mg/mL for 16 h, with or without dioscorin 100 mg/mL pretreatment for 8 h and with dioscorin 100 mg/mL alone for 16 h. Western blot was performed to detect changes in ZO-1, EC, and DP in the treated A549 cell lines.


RESULTS
Loss of tight junction protein expression (ZO-1, EC, DP) was demonstrated after 16-h mite extract incubation. The defect could be restored if cells were pretreated with dioscorin for 8 h. In addition, dioscorin did not cause damage to the A549 cell lines in terms of cell survival or morphology. Western blot showed no change in the amount of tight junction protein under various conditions.


CONCLUSIONS
Dioscorin is a potential protector of airway damage caused by mite extract.
Fu
Lin Shien
LS
Division of Immunology and Nephrology, Department of Pediatrics, Taichung Veterans General Hospital, Taichung, Taiwan. linshienfu@yahoo.com.tw
Ko
Ying Hsien
YH
Lin
Kuo Wei
KW
Hsu
Jeng Yuan
JY
Chu
Jao Jia
JJ
Chi
Chin Shiang
CS
D000818:Animals; D015153:Blotting, Western; D015820:Cadherins / Q000096:biosynthesis; D002460:Cell Line; D051180:Desmoplakins / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis; D008856:Microscopy, Fluorescence; D010750:Phosphoproteins / Q000096:biosynthesis; D010940:Plant Proteins / Q000494:pharmacology / Q000627:therapeutic use*; D039981:Pyroglyphidae; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology / Q000469:parasitology*; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
D015820:Cadherins; D051180:Desmoplakins; D008565:Membrane Proteins; D010750:Phosphoproteins; D010940:Plant Proteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; C095057:dioscorin protein, Dioscorea