Chronic Fibroproliferative Diseases Research Articles

PAI‐1 transcriptional regulation during the G0 → G1 transition in human epidermal keratinocytes

Plasminogen activator inhibitor type-1 (PAI-1) is the major negative regulator of the plasmin-dependent pericellular proteolytic cascade. PAI-1 gene expression is normally growth state regulated but frequently elevated in chronic fibroproliferative and neoplastic diseases affecting both stromal restructuring and cellular migratory activities. Kinetic modeling of cell cycle transit in synchronized human keratinocytes (HaCaT cells) indicated that PAI-1 transcription occurred early after serum stimulation of quiescent (G0) cells and prior to entry into a cycling G1 condition. PAI-1 repression (in G0) was associated with upstream stimulatory factor-1 (USF-1) occupancy of two consensus E box motifs (5'-CACGTG-3') at the PE1 and PE2 domains in the PF1 region (nucleotides -794 to -532) of the PAI-1 promoter. Chromatin immunoprecipitation (ChIP) analysis established that the PE1 and PE2 site E boxes were occupied by USF-1 in quiescent cells and by USF-2 in serum-activated, PAI-1-expressing keratinocytes. This reciprocal and growth state-dependent residence of USF family members (USF-1 vs. USF-2) at PE1/PE2 region chromatin characterized the G0 --> G1 transition period and the transcriptional status of the PAI-1 gene. A consensus E box motif was required for USF/E box interactions, as a CG --> AT substitution at the two central nucleotides inhibited formation of USF/probe complexes. The 5' flanking sites (AAT or AGAC) in the PE2 segment were not necessary for USF binding. USF recognition of the PE1/PE2 region E box sites required phosphorylation with several potential involved residues, including T153, maping to the USF-specific region (USR). A T153A substitution in USF-1 did not repress serum-induced PAI-1 expression whereas the T153D mutant was an effective suppressor. As anticipated from the ChIP results, transfection of wild-type USF-2 failed to inhibit PAI-1 induction. Collectively, these data suggest that USF family members are important regulators of PAI-1 gene control during serum-stimulated recruitment of quiescent human epithelial cells into the growth cycle.

Effect of Monthly Atorvastatin and Fenofibrate Treatment on Monocyte Chemoattractant Protein-1 Release in Patients with Primary Mixed Dyslipidemia

The aim of this study was to compare the effect of 30-day treatment with atorvastatin and fenofibrate on monocyte release and plasma levels of monocyte chemoattractant protein-1 (MCP-1). We studied 52 atherosclerotic patients with primary mixed dyslipidemia and 16 age-, sex-, and weight-matched control subjects with asymptomatic atherosclerosis. Dyslipidemic patients enrolled into the study were randomly divided into three groups, simultaneously treated with atorvastatin (20 mg/d, n = 18), fenofibrate (267 mg/d, n = 16), or placebo (n = 18). Plasma lipid-profile and content of MCP-1, and monocyte release of this chemokine were measured at baseline and after 30 days of therapy. Compared with the control subjects, dyslipidemic patients exhibited the increased plasma levels and monocyte MCP-1 release. Atorvastatin and fenofibrate not only improved lipid profile but also decreased monocyte secretion of this chemokine. Moreover, hypolipemic agents slightly reduced its plasma levels. MCP-1-lowering effect of atorvastatin and fenofibrate did not correlate with the lipid-lowering potential of these agents. Our results suggest that atorvastatin and fenofibrate produce their antiinflammatory effect partially via inhibiting monocyte release of MCP-1. The treatment-induced reduction in its secretion may contribute to the clinical effectiveness of statins and fibrates in the therapy for atherosclerosis and other chronic fibroproliferative diseases.

Poly (ADP) ribose synthetase inhibition reduces obliterative airway disease in rat tracheal allografts

Background Obliterative bronchiolitis (OB) is the major long-term complication affecting lung transplant recipients, and is characterized pathologically by chronic inflammatory and fibroproliferative airway disease. Based on studies revealing anti-inflammatory and anti-apoptotic properties of poly (ADP)-ribose synthetase (PARS) inhibitors, we hypothesized that their administration would be protective in a heterotopic model of experimental OB. Methods We transplanted rat tracheas from Brown-Norway donors into Lewis recipients, and treated 2 groups with a novel PARS inhibitor, INO-1001. One group received 14 days of treatment, whereas a second received delayed treatment beginning on Day 7 post-transplant. Tracheas were analyzed by light microscopy and computerized morphometry. Effects on cytokine transcription, nuclear transcription factor activation and cellular death were assessed by in situ hybridization for tumor necrosis factor-alpha (TNF-α), electromobility shift assays for nuclear factor-kappaB (NF-κB) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays, respectively. Results PARS inhibition significantly decreased luminal obstruction ( p < 0.001) and enhanced preservation of epithelial lining ( p < 0.001) at 14 days post-transplant. Day 7 controls confirmed the development of an obstructive lesion in the lumen, averaging 28% occlusion. Delayed treatment (beginning on Day 7) arrested ( p < 0.001) progression of the established lesion. Allograft airways treated with INO-1001 demonstrated attenuated NF-κB nuclear translocation, reduced transcription of TNF-α mRNA, and decreased cellular death on TUNEL and caspase 3 staining. Conclusions PARS inhibition is anti-inflammatory, protects against experimental OB, and is associated with enhanced preservation of respiratory epithelium and decreased cellular death. Delayed treatment with INO-1001 arrests progression of the lesion developed by Day 7. These studies suggest that activation of PARS plays a critical role in the development of airway obliterative disease.

The effects of cytokines on the atherosclerotic process.

Atherosclerotic lesions result from a series of highly specific cellular and molecular responses to various endogenous risk factors and potential exogenous antigens. The cellular mechanisms involved in atherogenesis, with the exception of calcification and thrombotic events, are principally no different to those found in chronic inflammatory fibroproliferative diseases such as liver cirrhosis, rheumatoid arthritis, glomerulosclerosis, pulmonary fibrosis or chronic pancreatitis. These responses are mediated by interactions among endothelial cells, monocyte-derived macrophages, smooth muscle cells and specific subtypes of T lymphocytes. Monocyte and lymphocyte activation leads to the release of a wide spectrum of cytokines and chemokines that have key roles in all of the phases of endothelial damage, as well as in the formation and rupture of the atherosclerotic plaques. This review attempts to analyze the role of chemokines and cytokines in the multiple steps of atherosclerotic process.