βγ-CAT, Induced Isolated Rabbit Thoracic Aortic Rings Sustained Contraction in Endothelial-dependent Manner

In vertebrates, non-lens βγ-crystallins are widely expressed in various tissues and their functions are not well known. The molecular mechanisms of trefoil factors (TFFs), which involved in mucosal healing and tumorigenesis, have remained elusive. βγ-CAT is a novel multifunctional protein complex of non-lens βγ-crystallin and trefoil factor from frog skin secretions. Here we report that βγ-CAT could induce sustained contraction of isolated rabbit aortic rings in dosage (2-35 nmol/L) and endothelium dependent manners (P<0.01). In addition, in situ immunofluorescence indicated that positive TNF-α signals were mainly detected at the endothelial cell layer of βγ-CAT (25 nmol/L) treated rings. Furthermore，βγ-CAT induced primary cultured rabbit thoracic aortic endothelial cells (RAECs) rapidly to release TNF-α. After βγ-CAT (25 nmol/L) treated for 10 and 30 min, the levels of the endothelial cells released TNF-α were 34.17±5.10 pg/mL and 98.01±4.67 pg/mL (P<0.01), respectively. In conclusion, βγ-CAT could induce sustained contraction of isolated aortic rings, and the contractile effect might be partially explained by the release of TNF-α. These findings will give new insight into understanding the functions and physiological roles of non-lens βγ-crystallins and trefoil factors.

Keywords
Tumor necrosis factor-a; Trefoil factor; Non-lens bg-crystallin; Endothelium-dependent aorta vasoconstriction; bg-CAT