sirolimus and Nasal-Polyps

Rapamycin has antiproliferative and antifibrogenic effects in vitro and in vivo. The purpose of this study was to evaluate the effects of rapamycin on transforming growth factor (TGF) beta 1 induced myofibroblast differentiation (alpha smooth-muscle actin [SMA]), extracellular matrix production, and collagen contraction in nasal polyp-derived fibroblasts (NPDF). The underlying molecular mechanisms of rapamycin were also determined in NPDFs.. NPDFs were grown in culture and transformed into myofibroblasts by using TGF beta 1 (5 ng/mL). For cytotoxicity evaluation, a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay was used. Expression levels of alpha SMA, phosphorylated phosphatidylinositol 3-kinase (PI3K), and phosphorylated mammalian target of rapamycin (mTOR) were determined by using Western blot, reverse transcription-polymerase chain reaction, and immunofluorescence staining. The total amount of collagen was analyzed by using the Sircol collagen assay, and contractile activity was measured with a collagen gel contraction assay. Silencing mTOR with mTOR-specific small interference RNA was determined by using reverse transcription-polymerase chain reaction.. Whereas rapamycin (range, 0-400 nM) had no significant cytotoxic effects on TGF beta 1 induced NPDFs, it significantly reduced the expression levels of alpha-SMA in TGF beta 1 induced NPDFs in a dose-dependent manner. TGF beta 1 induced collagen production and collagen contraction were significantly inhibited by rapamycin treatment. Rapamycin also attenuated the TGF beta 1 induced activation of PI3K and mTOR, and its inhibitory effects were similar to those of mTOR silencing and a specific PI3K inhibitor.. Rapamycin inhibited TGF beta 1 induced myofibroblast differentiation, extracellular matrix production, and collagen contraction through the PI3K/mTOR signal pathways in NPDFs.

Topics: Actins; Cell Differentiation; Cells, Cultured; Collagen; Extracellular Matrix; Fibroblasts; Humans; Immunosuppressive Agents; Myofibroblasts; Nasal Polyps; Phosphatidylinositol 3-Kinase; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transforming Growth Factor beta

Decreased infiltration of Foxp3+ T regulatory cell (Treg) is considered to be critical for the Th1/Th2 dysregulation of nasal polyps, while the cellular mechanism underlying Foxp3+ Treg insufficiency is currently not well defined.. We attempted to investigate the tissue expression of phosphorylated mammalian target of rapamycin (pmTOR) and infiltration of Foxp3+ Tregs in 28 nasal polyps and 16 controls by histological staining. We also evaluated the effects of blocking the mTOR signaling pathway with rapamycin on T cell phenotype selection and Foxp3+CD4+ Tregs expansion in a tissue culture system.. Significantly increased infiltration of pmTOR+ inflammatory cells and decreased infiltration of Foxp3+CD4+ Tregs into nasal polyps was observed, with an inverse association. In the tissue culture system, we detected significantly elevated Foxp3 expression and IL-10 production, as well as an increased percentage of Foxp3+ Tregs in nasal polyps after blocking the mTOR signaling pathway with rapamycin.. Here we demonstrate for the first time that the mTOR signaling pathway is associated with Foxp3+ Tregs insufficiency in nasal polyps. Inhibition of the mTOR signaling pathway may be helpful for enhancement of Foxp3+ Treg expansion, as well as modulation of T cell phenotype imbalances in nasal polyps.

Topics: Adult; Case-Control Studies; Female; Fluorescent Antibody Technique; Forkhead Transcription Factors; GATA3 Transcription Factor; Humans; Immunohistochemistry; Immunosuppressive Agents; Interleukin-10; Male; Middle Aged; Nasal Polyps; Nuclear Receptor Subfamily 1, Group F, Member 3; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinases; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Receptors, Retinoic Acid; Receptors, Thyroid Hormone; Rhinitis; Signal Transduction; Sinusitis; Sirolimus; T-Box Domain Proteins; T-Lymphocytes, Regulatory; Tissue Culture Techniques; TOR Serine-Threonine Kinases; Young Adult