Medicine and Health Sciences Commons^™

Decreased Expression Of Caveolin 1 In Patients With Systemic Sclerosis: Crucial Role In The Pathogenesis Of Tissue Fibrosis., Francesco Del Galdo, Federica Sotgia, Cecilia J. De Almeida, Jean-Francois Jasmin, Megan Musick, Michael P. Lisanti, Sergio A. Jimenez

Department of Medicine Faculty Papers

OBJECTIVE: Recent studies have implicated caveolin 1 in the regulation of transforming growth factor beta (TGFbeta) downstream signaling. Given the crucial role of TGFbeta in the pathogenesis of systemic sclerosis (SSc), we sought to determine whether caveolin 1 is also involved in the pathogenesis of tissue fibrosis in SSc. We analyzed the expression of CAV1 in affected SSc tissues, studied the effects of lack of expression of CAV1 in vitro and in vivo, and analyzed the effects of restoration of caveolin 1 function on the fibrotic phenotype of SSc fibroblasts in vitro.

METHODS: CAV1 expression in tissues was analyzed by …

Modulation Of Tgf-Beta Signaling By Proinflammatory Cytokines In Articular Chondrocytes., Jorge A. Roman-Blas, David G. Stokes, Sergio A. Jimenez

Department of Medicine Faculty Papers

OBJECTIVE: The normal structure and function of articular cartilage are the result of a precisely balanced interaction between anabolic and catabolic processes. The transforming growth factor-beta (TGF-beta) family of growth factors generally exerts an anabolic or repair response; in contrast, proinflammatory cytokines such as interleukin 1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) exert a strong catabolic effect. Recent evidence has shown that IL-1beta, and TNF-alpha, and the TGF-beta signaling pathways share an antagonistic relationship. The aim of this study was to determine whether the modulation of the response of articular chondrocytes to TGF-beta by IL-1beta or TNF-alpha signaling pathways …

Transcriptional Inhibition Of Type I Collagen Gene Expression In Scleroderma Fibroblasts By The Antineoplastic Drug Ecteinascidin 743., Natalia Louneva, Biagio Saitta, David J Herrick, Sergio A. Jimenez

Department of Medicine Faculty Papers

We previously showed that COL1A1 expression is up-regulated at the transcriptional level in systemic sclerosis (SSc) fibroblasts and that the CCAAT-binding factor (CBF) is involved in this increased expression. Ecteinascidin 743 (ET-743) is a chemotherapeutic agent that binds with sequence specificity to the minor groove of DNA and inhibits CBF-mediated transcriptional activation of numerous genes. Therefore, we examined the effects of ET-743 on the increased COL1A1 expression in SSc fibroblasts. The drug caused a potent and dose-dependent inhibition of type I collagen biosynthesis, which reached 70-90% at 700 pM without affecting cell viability. The same drug concentration caused 60-80% reduction …

Increased Alpha 1(I) Procollagen Gene Expression In Tight Skin (Tsk) Mice Myocardial Fibroblasts Is Due To A Reduced Interaction Of A Negative Regulatory Sequence With Ap-1 Transcription Factor., Neena Philips, Reza I. Bashey, Sergio A. Jimenez

Department of Medicine Faculty Papers

The TSK mouse, a model of fibrosis, displays exaggerated connective tissue accumulation in skin and visceral organs including the heart. To study the mechanisms of myocardial fibrosis in TSK mice, we established several strains of TSK mice myocardial fibroblasts in culture and examined the regulation of collagen gene expression in these cells. These strains displayed increased collagen gene expression in comparison with myocardial fibroblasts established from normal mice. On an average, the TSK myocardial fibroblast cultures showed a 4-fold increase in collagen synthesis and 4.4- and 3.6-fold increases, respectively, in alpha 1(I) and alpha 1(III) collagen mRNA steady state levels. …

Epidermal Growth Factor Coordinately Regulates The Expression Of Prostaglandin G/H Synthase And Cytosolic Phospholipase A2 Genes In Embryonic Mouse Cells., Kenneth P. Chepenik, Arturo Diaz, Sergio A. Jimenez

Department of Medicine Faculty Papers

Confluent, primary cultures of mouse embryo palate mesenchyme (MEPM) cells are refractory to activation of phospholipase A2 (PLA2) by the calcium ionophore A23187. However, treatment of these cultures with epidermal growth factor (EGF) permits the cells to activate PLA2 in response to A23187. We have developed this finding by exploring molecular mechanisms by which growth factors modulate mobilization and metabolism of arachidonic acid. We found chronic treatment (> 6 h) of confluent MEPM cells with EGF (a) increases their ability to metabolize exogenous arachidonic acid to prostaglandin E2 (PGE2) and (b) stimulated constitutive expression of activities of PLA2 and cyclooxygenase …

Regulation Of Human Lung Fibroblast Alpha 1(I) Procollagen Gene Expression By Tumor Necrosis Factor Alpha, Interleukin-1 Beta, And Prostaglandin E2., Arturo Diaz, Elena Munoz, Rosemary Johnston, Joseph H. Korn, Sergio A. Jimenez

Department of Medicine Faculty Papers

We investigated the participation of prostaglandin (PG) E2 in the regulation of the alpha 1(I) procollagen gene expression by tumor necrosis factor alpha (TNF alpha), and interleukin-1 beta (IL-1 beta) in normal adult human lung fibroblasts. TNF alpha (100 units/ml) and IL-1 beta (100 units/ml) stimulated the production of PGE2 and caused a dose-dependent inhibition of up to 54 and 66%, respectively, of the production of type I procollagen. Preincubation of cultures with indomethacin partially reversed the inhibition of procollagen production induced by the cytokines. Cytokine-stimulated endogenous fibroblast PG accounted for 35 and 68% of the inhibition induced by TNF …

Alternative Splicing Of Human Prostaglandin G/H Synthase Mrna And Evidence Of Differential Regulation Of The Resulting Transcripts By Transforming Growth Factor Beta 1, Interleukin 1 Beta, And Tumor Necrosis Factor Alpha., Arturo Diaz, Anthony M. Reginato, Sergio A. Jimenez

Department of Medicine Faculty Papers

Prostaglandin G/H synthase (PGG/HS) is the rate-limiting enzyme in the conversion of arachidonic acid to prostaglandins and thromboxanes. We screened a human lung fibroblast cDNA library with an ovine PGG/HS cDNA and isolated a 2.3-kilobase clone (HCO-T9). Sequence analysis of this clone showed that (a) it contained the entire translated region of PGG/HS and (b) it displayed an in-frame splicing of the last 111 base pairs encoded by exon 9, which resulted in the elimination of the N-glycosylation site at residue 409. Polymerase chain reaction amplification with specific oligonucleotides of reverse-transcribed mRNA from diverse human tissues and cultured cells yielded …

Expression Of A Human Cartilage Procollagen Gene (Col2a1) In Mouse 3t3 Cells., Leena Ala-Kokko, James Hyland, Carol Smith, Kari I. Kivirikko, Sergio A. Jimenez, Darwin J. Prockop

Department of Medicine Faculty Papers

Expression in a recombinant system has been difficult to obtain for any of the major fibrillar collagens that require processing by eight or more post-translational enzymes. Here, two DNA constructs were designed so that the promoter region of the gene for the pro-alpha 1(I) chain of human type I procollagen drove expression of the human type II procollagen gene in mouse NIH 3T3 cells, a culture line that normally synthesizes type I procollagen but not any cartilage-specific protein such as type II procollagen. Both constructs were expressed as both mRNA and protein. In clones expressing the construct at high levels, …

Transforming Growth Factor-Beta Stimulation Of Lung Fibroblast Prostaglandin E2 Production., Arturo Diaz, John Varga, Sergio A. Jimenez

Department of Medicine Faculty Papers

Transforming growth factor-beta (TGF beta) stimulated the production of total protein, collagen, and fibronectin by normal human lung fibroblasts. The stimulatory response was maximal at 100 pM TGF beta and reversed toward control at higher concentrations. Inhibition of fibroblast prostaglandin (PG) synthesis enhanced TGF beta-induced stimulation of total protein, collagen, and fibronectin production and reversed the negative slope of the dose-response curve at high concentrations of TGF beta. Determination of the steady-state levels of Types I and III procollagens and fibronectin mRNAs employing specific cDNA probes demonstrated that inhibition of fibroblast PG production increased the stimulatory effect of TGF beta …