hts-466284 and Fibrosis

The cytokine transforming growth factor beta (TGFβ) has a role in regulating the normal and pathological response to wound healing, yet how it shifts from a pro-repair to a pro-fibrotic function within the wound environment is still unclear. Using a clinically relevant ex vivo post-cataract surgery model that mimics the lens fibrotic disease posterior capsule opacification (PCO), we investigated the influence of two distinct wound environments on shaping the TGFβ-mediated injury response of CD44

Topics: Actins; Animals; Blotting, Western; Capsule Opacification; Cataract Extraction; Cell Proliferation; Chick Embryo; Collagen Type I; Disease Models, Animal; Fibronectins; Fibrosis; Hyaluronan Receptors; Imidazoles; Integrin alphaVbeta3; Microscopy, Fluorescence; Myofibroblasts; Posterior Capsule of the Lens; Postoperative Complications; Pyrazoles; Pyrroles; Quinoxalines; Receptor, Transforming Growth Factor-beta Type I; Signal Transduction; Transforming Growth Factor beta; Wound Healing

Inflammation is recognized as an important contributor to lymphangiogenesis; however, in tubulointerstitial lesions in human chronic kidney diseases, this process is better correlated with the presence of myofibroblasts rather than macrophages. As little is known about the interaction between lymphangiogenesis and renal fibrosis, we utilized the rat unilateral ureteral obstruction model to analyze inflammation, fibrosis, lymphangiogenesis, and growth factor expression. Additionally, we determined the relationship between vascular endothelial growth factor-C (VEGF-C), an inducer of lymphangiogenesis, and the profibrotic factor, transforming growth factor-β1 (TGF-β1). The expression of both TGF-β1 and VEGF-C was detected in tubular epithelial and mononuclear cells, and gradually increased, peaking 14 days after ureteral obstruction. The kinetics and localization of VEGF-C were similar to those of TGF-β1, and the expression of these growth factors and lymphangiogenesis were linked with the progression of fibrosis. VEGF-C expression was upregulated by TGF-β1 in cultured proximal tubular epithelial cells, collecting duct cells, and macrophages. Both in vitro and in vivo, the induction of VEGF-C along with the overall appearance of lymphatics in vivo was specifically suppressed by the TGF-β type I receptor inhibitor LY364947. Thus, TGF-β1 induces VEGF-C expression, which leads to lymphangiogenesis.

Topics: Animals; Cell Line; Disease Models, Animal; Fibroblasts; Fibrosis; Humans; Kidney Tubules; Lymphangiogenesis; Macrophages; Male; Membrane Glycoproteins; Mice; Protein Serine-Threonine Kinases; Pyrazoles; Pyrroles; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptor, Transforming Growth Factor-beta Type I; Receptors, Cell Surface; Receptors, Transforming Growth Factor beta; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Time Factors; Transforming Growth Factor beta1; Up-Regulation; Ureteral Obstruction; Vascular Endothelial Growth Factor C

Cell-specific targeting to renal tubular cells is an interesting approach to enhance the accumulation of drugs in the kidney. Low molecular weight proteins are rapidly filtered and extensively accumulate in proximal tubular cells. We therefore have used lysozyme (LZM, 14 kDa) as a tubular cell-specific carrier for the delivery of kinase inhibitors. Two different kinase inhibitors (LY364947 and erlotinib, directed to either the TGF-beta receptor kinase or the EGF receptor) were individually conjugated to LZM via a novel platinum-based linker (Universal Linkage System; ULS). The cellular handling and pharmacological efficacy of the conjugates were evaluated in cultured proximal tubular cells (HK-2 cells). Both conjugates were efficiently internalized via endocytosis. TGF-beta or EGF activated HK-2 cells showed a strong activation of the studied kinases and the conjugates inhibited these events, as was demonstrated by Western blotting of phosphorylated downstream mediators and quantitative gene expression analysis. In conclusion, we have developed tubular cell-specific kinase inhibitor-LZM conjugates via a novel linker strategy, which both showed to be effective in vitro. Future in vivo studies should show their potential for the treatment of renal diseases.

Topics: Cells, Cultured; Chemistry, Pharmaceutical; Drug Carriers; Endocytosis; Epidermal Growth Factor; ErbB Receptors; Erlotinib Hydrochloride; Fibrosis; Gene Expression Regulation; Humans; Intercellular Signaling Peptides and Proteins; Kidney Tubules, Proximal; Kinetics; Muramidase; Phosphorylation; Protein Kinase Inhibitors; Pyrazoles; Pyrroles; Quinazolines; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta