| 발표일자: |
2019년 11월 1일(금)~3(일) |
| 발표번호: |
P(e-poster)-387 |
| 발표장소: |
B3 Parking Area
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| PPARγ activation leads to meibocyte differentiation, cell cycle exit and autophagy in human meibomian gland epithelial cells |
| Yonsei University Wonju College of Medicine (1)
Daejeon St Mary Hospital (2)
University of California, Irvine (3) |
| Sun Woong Kim1, Chang Rae Rho2, Donald J. Brown3, James V. Jester3 |
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Purpose : To investigate role of PPARγ signaling during differentiation of human meibomian gland epithelial cells (hMGEC)
Methods : HMGEC were exposed to rosiglitazone or eicosapentaenoic acid (EPA). Cultures were also exposed to specific PPARγ antagonist, T0070907, to block PPARγ signaling. Effect on cell cycle was evaluated using Ki-67 labelling and western blots. Expression of PPARγ response genes were evaluated by qPCR. During differentiation, autophagy was monitored using the Autophagy Tandem Sensor (RFP-GFP-LC3B) kit and LysoTracker. Intracellular compartmental localization of lipid was identified using Lipi-Blue or Bodipy 493/503 staining in combination with ER-Tracker, LysoTracker, and the Autophagy Tandem Sensor. Activation of autophagy was also investigated using western blotting. Seahorse XF analysis was performed to monitor mitochondrial function.
Results : A specific PPARγ agonist, rosiglitazone and possible natural ligand, EPA reduced Ki-67 labeling and cyclin D1 expression along with increase of p21 and p27 leading to cell cycle exit. EPA induced accumulation of lipid droplets in time and dose dependent manners. Both ligands upregulated expression of genes related to meibum synthesis and these upregulations were suppressed by PPARγ antagonist. During PPARγ-induced differentiation, autophagy was increased by activating AMPK-ULK1 signaling pathway. Accumulated lipid droplets were localized in ER and not co-localized with either autophagosome or lysosome. Inhibition of autophagy did not alter lipid accumulation during exposure to PPARγ agonists. Inhibition of autophagy induced mitochondrial crisis when cells were co-exposed to PPARγ agonists.
Conclusion : PPARγ activation inhibited cell cycle progression, induced accumulation of neutral lipid droplet, and progressed autophagy during maturation of hMGEC
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