Cai-Xia Li1, Li-Hua Cui1, Yu-Zhen Zhuo1, Jian-Gong Hu2, Nai-Qiang Cui3, Shu-Kun Zhang4. 1. Department of Cell and Molecular Biology, Institute of Integrated Traditional Chinese and Western Medicine, Nankai Hospital, Tianjin 300100, China; Nankai Clinical College, Tianjin Medical University, Tianjin 300107, China. 2. Department of Pathology, the Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300150, China. 3. Nankai Clinical College, Tianjin Medical University, Tianjin 300107, China; Hepatobiliary and Pancreatic Surgery, Nankai Hospital, Tianjin 300100, China. 4. Department of Cell and Molecular Biology, Institute of Integrated Traditional Chinese and Western Medicine, Nankai Hospital, Tianjin 300100, China; Nankai Clinical College, Tianjin Medical University, Tianjin 300107, China. Electronic address: shu1971@163.com.
Abstract
AIMS: Autophagy is an intracellular metabolic process that degrades and recycles own constituents to maintain homeostasis and supply substrates. Disruption of collagen degradation is one of the pathogenesis of pancreatic fibrosis. In this study, we investigated the effects of inhibiting autophagy on the collagen degradation of PSCs. MAIN METHODS: Rats were injected dibutyltin dichloride (DBTC) to induce chronic pancreatitis (CP) model. The expression of LC3B was measured by western blotting. Rat PSCs were isolated from pancreas tissues, and the experiments used the primary PSCs. Autophagosome was confirmed by transmission electron microscope. Immunofluorescence for LC3B and α-SMA were applied to assess autophagy and activated PSCs. The effects of autophagy inhibition of 3-MA on the expressions of LC3B, Atg5, and Beclin-1 were investigated by real-time PCR and Western blotting, as well as the α-SMA, TGF-β1, ColI, Col III, FN, MMP-2, MMP-13, TIMP-1 and TIMP-2. Meanwhile, the secretion of ColI, Col III and FN were investigated by ELISA. KEY FINDINGS: The LC3-II/I ratio was increased in rat CP model. Autophagosomes and an increased autophagic level were observed during PSCs activation. Inhibiting autophagy could down-regulate the expressions of α-SMA, TGF-β1, FN, ColI, Col III, TIMP-1 and TIMP-2, while the expressions of MMP-2 and MMP-13 were increased. SIGNIFICANCE: This study confirmed that autophagic level is increased during PSCs activation in vivo and in vitro. Inhibiting autophagy prevents the activation of PSCs, and suppresses fibrosis through promoting extracellular matrix (ECM) degradation by decreasing the expression of TGF-β1 and increasing MMPs/TIMPs ratio.
AIMS: Autophagy is an intracellular metabolic process that degrades and recycles own constituents to maintain homeostasis and supply substrates. Disruption of collagen degradation is one of the pathogenesis of pancreatic fibrosis. In this study, we investigated the effects of inhibiting autophagy on the collagen degradation of PSCs. MAIN METHODS:Rats were injected dibutyltin dichloride (DBTC) to induce chronic pancreatitis (CP) model. The expression of LC3B was measured by western blotting. Rat PSCs were isolated from pancreas tissues, and the experiments used the primary PSCs. Autophagosome was confirmed by transmission electron microscope. Immunofluorescence for LC3B and α-SMA were applied to assess autophagy and activated PSCs. The effects of autophagy inhibition of 3-MA on the expressions of LC3B, Atg5, and Beclin-1 were investigated by real-time PCR and Western blotting, as well as the α-SMA, TGF-β1, ColI, Col III, FN, MMP-2, MMP-13, TIMP-1 and TIMP-2. Meanwhile, the secretion of ColI, Col III and FN were investigated by ELISA. KEY FINDINGS: The LC3-II/I ratio was increased in rat CP model. Autophagosomes and an increased autophagic level were observed during PSCs activation. Inhibiting autophagy could down-regulate the expressions of α-SMA, TGF-β1, FN, ColI, Col III, TIMP-1 and TIMP-2, while the expressions of MMP-2 and MMP-13 were increased. SIGNIFICANCE: This study confirmed that autophagic level is increased during PSCs activation in vivo and in vitro. Inhibiting autophagy prevents the activation of PSCs, and suppresses fibrosis through promoting extracellular matrix (ECM) degradation by decreasing the expression of TGF-β1 and increasing MMPs/TIMPs ratio.