Rapamycin Inhibits Transforming Growth Factor beta1-Induced Fibrogenesis in Primary Human Lung Fibroblasts

PURPOSE: The present study was designed to determine whether rapamycin could inhibit transforming growth factor beta1 (TGF-beta1)-induced fibrogenesis in primary lung fibroblasts, and whether the effect of inhibition would occur through the mammalian target of rapamycin (mTOR) and its downstream p70S6K pathway. MATERIALS AND METHODS: Primary normal human lung fibroblasts were obtained from histological normal lung tissue of 3 patients with primary spontaneous pneumothorax. Growth arrested, synchronized fibroblasts were treated with TGF-beta1 (10 ng/mL) and different concentrations of rapamycin (0.01, 0.1, 1, 10 ng/mL) for 24 h. We assessed m-TOR, p-mTOR, S6K1, p-S6K1 by Western blot analysis, detected type III collagen and fibronectin secreting by ELISA assay, and determined type III collagen and fibronectin mRNA levels by real-time PCR assay. RESULTS: Rapamycin significantly reduced TGF-beta1-induced type III collagen and fibronectin levels, as well as type III collagen and fibronectin mRNA levels. Furthermore, we also found that TGF-beta1-induced mTOR and p70S6K phosphorylation were significantly down-regulated by rapamycin. The mTOR/p70S6K pathway was activated through the TGF-beta1-mediated fibrogenic response in primary human lung fibroblasts. CONCLUSION: These results indicate that rapamycin effectively suppresses TGF-beta1-induced type III collagen and fibronectin levels in primary human lung fibroblasts partly through the mTOR/p70S6K pathway. Rapamycin has a potential value in the treatment of pulmonary fibrosis.

MORPHOLOGICAL DEMONSTRATION OF NON-SYNAPTIC RELEASE OF SUBSTANCE P IN RAT / 解剖学报

Previous studies have demonstrated that exocytotic release from large dense cored vesicle(LDV)at structurally non-specialized areas within axon terminal of the medullary dorsal horn and it has been speculated that non-synaptic exocytosis from LDV may be a probable mechanism for neuropeptide release. This study provides the evidence that SP containing LDV can release their contents by exocytosis at non-synaptic sites of axon terminal within superficial dorsal horn of medulla oblongata in the rat with ultrastructural immunohistochemistry staining by an unilateral deafferentation. The results of this study confirmed previous hypothesis that SP and perhaps other peptides containing LDV release their contents by exocytosis at non-specialized sites and the significance of such release is discussed.

THE DISTRIBUTION OF LARGE GRANULAR VESICLES IN SUBSTANCE P AXON TERMINALS AND THEIR SYNAPTIC RELATIONS IN THE TRIGEMINAL SUBNUCLEUS CAUDALIS / 解剖学报

The ultrastructural localization of substance P (SP) immunoreactivity, especially the morphology, number and distribution of positive large granular vesicles (LGV) in SP axon terminals of the trigeminal subnucleus caudalis of the rat were studied by electron microscopic immunocytochemistry. This study revealed that SP immunoreactivity was mostly located in axon terminals and unmyelinated fibers. SP axon terminals contained both clear round vesicles and LGV. SP immunoreactivity was found in LGV, and on the surface of clear round vesicles and outer membrane of mitochondria. Positive LGV were spherical or oval in shape (60～120nm in diameter). The number of LGv was mostly 2～3 in a SP axon terminal. LGV often apposed to the axolemma or scattered in the centre of terminal. LGV were far from the presynaptic sites of the SP terminals which formed synapses. The number of LGV closed to the terminal membrane was significantly (P