The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen activation or NF-kappaB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-kappaB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10(-3) mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P < 0.01) following the treatment with a high concentration of carbachol (10(-3) mol/L) in vitro. The addition of 10(-2) mol/L PDTC didn't result in a significant decrease in the activity of trypsin and the leakage of LDH from pancreatic acinar cells treated with a high concentration of carbachol (10(-3) mol/L) in vitro (P > 0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-kappaB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.
Carbachol/*pharmacology ; Cholinergic Agonists/pharmacology ; NF-kappa B/*metabolism ; Pancreas/metabolism ; Pancreas/*pathology ; Rats, Wistar ; Receptor, Muscarinic M3/agonists ; Trypsinogen/*metabolism

OBJECTIVETo investigate the relation between transdifferentiation of the airway myofibroblasts and the expression level of (trypsinogen16, TG16) in vitro and explore the mechanism of airway basement membrane thickening.

METHODSThe total lung proteins were extracted from normal and OVA-induced asthmatic mice and the protein expression profiles were analyzed with SDS-PAGE. The differentially expressed proteins were isolated for analysis with liquid chromatography-mass spectrometry. TG16 was cloned from mouse lung tissue and subcloned into the expression vector pcDNA3.0 to generate a pcDNA3-TG16 plasmid. The vectors were transfected into mouse embryonic fibroblast 3T3 cells and cultured in MEM in the presence of transforming growth factor-beta1 (TGF-beta1). The mRNA levels of alpha-actin and the housekeeping GAPDH gene were analyzed with RT-PCR. Using RNA interference, TG16 expression was suppressed and the resultant alpha-actin or GAPDH protein levels were analyzed using Western blotting.

RESULTSIn the total lung proteins from OVA-induced mice, a 25 000 Da protein was significantly enhanced in comparison with the protein profiles of normal mice. The protein band was identified to represent the protein of TG16. With TGF-beta1 stimulation, transfection with the plasmid pcDNA3-TG16 significantly suppressed the mRNA expression of alpha-actin (alpha-actin/GAPDH=1.78-/+0.50) in 3T3 cells as compared with the expression in cells transfected with pcDNA3.0 (3.20-/+1.36); transfection of the cells with TG16 stealth RNAi oligonucleotide to decrease TG16 mRNA level upregulated the protein level of alpha-actin (3.60-/+0.44) as compared with the alpha-actin protein level in 3T3 cells transfected with control oligonucleotide (2.78-/+0.50).

CONCLUSIONTG16 can inhibit the expression of alpha-actin in fibroblasts, which might be a protective mechanism in the progression of airway remodeling in asthma.

3T3 Cells ; Actins ; biosynthesis ; genetics ; Animals ; Cell Transdifferentiation ; drug effects ; genetics ; physiology ; Chromatography, Liquid ; Fibroblasts ; cytology ; drug effects ; metabolism ; Lung ; cytology ; metabolism ; Male ; Mass Spectrometry ; Mice ; Mice, Inbred BALB C ; Myoblasts ; cytology ; drug effects ; metabolism ; Proteomics ; methods ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; Transforming Growth Factor beta1 ; pharmacology ; Trypsinogen ; genetics ; metabolism