title: Dibutyryl-cAMP attenuates pulmonary fibrosis by blocking myofibroblast differentiation via PKA/CREB/CBP signaling in rats with silicosis.
abstract: Myofibroblasts play a major role in the synthesis of extracellular matrix (ECM) and the stimulation of these cells is thought to play an important role in the development of silicosis. The present study was undertaken to investigate the anti-fibrotic effects of dibutyryl-cAMP (db-cAMP) on rats induced by silica.
  
  
  
  A HOPE MED 8050 exposure control apparatus was used to create the silicosis model. Rats were randomly divided into 4 groups: 1)controls for 16 w; 2)silicosis for 16 w; 3)db-cAMP pre-treatment; 4) db-cAMP post-treatment. Rat pulmonary fibroblasts were cultured in vitro and divided into 4 groups as follows: 1) controls; 2) 10-7mol/L angiotensin II (Ang II); 3) Ang II +10-4mol/L db-cAMP; and 4) Ang II + db-cAMP+ 10-6mol/L H89. Hematoxylin-eosin (HE), Van Gieson staining and immunohistochemistry (IHC) were performed to observe the histomorphology of lung tissue. The levels of cAMP were detected by enzyme immunoassay. Double-labeling for α-SMA with Gαi3, protein kinase A (PKA), phosphorylated cAMP-response element-binding protein (p-CREB), and p-Smad2/3 was identified by immunofluorescence staining. Protein levels were detected by Western blot analysis. The interaction between CREB-binding protein (CBP) and Smad2/3 and p-CREB were measured by co-immunoprecipitation (Co-IP).
  
  
  
  Db-cAMP treatment reduced the number and size of silicosis nodules, inhibited myofibroblast differentiation, and extracellular matrix deposition in vitro and in vivo. In addition, db-cAMP regulated Gαs protein and inhibited expression of Gαi protein, which increased endogenous cAMP. Db-cAMP increased phosphorylated cAMP-response element-binding protein (p-CREB) via protein kinase A (PKA) signaling, and decreased nuclear p-Smad2/3 binding with CREB binding protein (CBP), which reduced activation of p-Smads in fibroblasts induced by Ang II.
  
  
  
  This study showed an anti-silicotic effect of db-cAMP that was mediated via PKA/p-CREB/CBP signaling. Furthermore, the findings offer novel insight into the potential use of cAMP signaling for therapeutic strategies to treat silicosis.
authors.affiliation: Basic Medical College, Hebei Medical University, No. 361 Zhongshan Road, Shijiazhuang city, Hebei province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Yucong
authors.initials: Y
authors.lastname: Geng
authors.affiliation: Traditional Chinese Medicine College, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Dingjie
authors.initials: D
authors.lastname: Xu
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Basic Medical College, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Zhongqiu
authors.initials: Z
authors.lastname: Wei
authors.affiliation: Basic Medical College, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Bonan
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Li
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Xuemin
authors.initials: X
authors.lastname: Gao
authors.affiliation: Medical Research Center, North China University of Science and Technology, Tangshan, Hebei, 063009, China.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Basic Medical College, Hebei Medical University, No. 361 Zhongshan Road, Shijiazhuang city, Hebei province, China.
authors.forename: Xianghong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
authors.forename: Darrell
authors.initials: D
authors.lastname: Brann
authors.affiliation: Basic Medical College, Hebei Medical University, No. 361 Zhongshan Road, Shijiazhuang city, Hebei province, China. fangyang990404@sina.com.
authors.forename: Fang
authors.initials: F
authors.lastname: Yang
mesh_terms: D000818:Animals; D001195:Asbestosis / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D050882:CREB-Binding Protein / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003563:Cyclic CMP / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D058628:Myofibroblasts / Q000187:drug effects* / Q000473:pathology; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D008565:Membrane Proteins; C408142:Pag1 protein, rat; D010750:Phosphoproteins; D003563:Cyclic CMP; C053441:dibutyryl cyclic-3',5'-cytidine monophosphate; D050882:CREB-Binding Protein; C494365:Crebbp protein, rat; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: CAMP; CREB; Myofibroblast; PKA; Silicosis; Smad