Figure 2.

Expression of AQP3 and TIMP3 and the effect of synthetic metalloproteinase inhibitor 3 (TIMP3) peptides on tumor necrosis factor-α (TNF-α) secretion in ultraviolet B (UVB)-irradiation conditions. NHEKs were treated with 20 mJ/cm² UVB at zeitgeber time (ZT) 2 and harvested every 4 h. The expression of AQP3 (A) and TIMP3 (B) was downregulated by UVB irradiation but recovered at ZT 24; (C) The secreted or cytosolic TIMP3 and aquaporin 3 (AQP3) were examined at ZT 8 and 24 after UVB irradiation. UVB irradiation reduced the protein levels of both TIMP3 and AQP3. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was loaded as the control; (D) Synthetic TIMP3-peptides were used to treat the cells with or without UVB irradiation (Figure 3). TIMP3, AQP3, and the secreted TNF-α protein levels were analyzed using Western blotting at ZT 8 and 24. The synthetic TIMP3-peptides inhibited UVB-induced TNF-α secretion. GAPDH was loaded as control. Sync indicates synchronization.