Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Investigation of the molecular mechanisms that control smooth muscle cell (SMC) development and differentiation is a prerequisite in understanding the regulatory mechanisms of physiological and pathological SMC-associated vascular processes. The pluripotent murine embryonal carcinoma P19 cell, whose developmental potential resembles that of early embryonic cells, can develop into cell types derived from the neuroectoderm, mesoderm, and endoderm. In the present study, we have shown a unique strategy to enhance SMC differentiation in P19 cells. Under chemical induction of high concentrations of retinoic acid (1 micromol/L), P19 cells showed optimum differentiation into SMCs. Because the P19 cells thus induced also showed differentiation into neuronal cells, a strategy to block neuronal lineage differentiation was developed using a stable transformant antisense RNA construct against Brn-2, a neuronal lineage-specific POU-domain transcription factor; thus, by specifically inhibiting neuronal differentiation, enhanced SMC differentiation by P19 cells was attained. SMC expression was confirmed by immunohistochemical staining, RNA analysis (RNase protection assay), and protein analysis (Western blot) using SMC-specific markers (eg, SM1 and calponin) and alpha-smooth muscle actin. Our results show that the pathway of SMC differentiation may provide an in vitro system useful in the investigation of SMC regulatory mechanisms (eg, transcriptional regulation) and in the further understanding of SMC development and differentiation.
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PMID:Preferential differentiation of P19 mouse embryonal carcinoma cells into smooth muscle cells. Use of retinoic acid and antisense against the central nervous system-specific POU transcription factor Brn-2. 859 98

To characterize the phenotypic modulation of mesangial and glomerular epithelial cells, we investigated the expression of a nonmuscle type myosin heavy chain, SMemb, and alpha-smooth muscle actin (alpha-SM actin) in rat experimental glomerular diseases, which included anti-Thy 1 nephritis, 5/6 nephrectomy, diabetes, and anti-glomerular basement membrane nephritis. SMemb was only slightly expressed in normal glomerular epithelial cells but not in mesangial cells. In the anti-Thy 1 nephritis rats, both SMemb and alpha-SM actin were most conspicuously induced in mesangial cells. However, the expression profile was shifted from alpha-SM actin to SMemb dominant pattern over the course of glomerulonephritis. The expression of SMemb was also increased in epithelial cells in this model. In the other three models, glomerular cells did not express alpha-SM actin, but did so for SMemb. In the nephrectomized and the diabetic rats SMemb was newly expressed in mesangial cells at earlier stages, but at later stages was remarkably enhanced in epithelial cells when severe glomerular hypertrophy developed. In the anti-GBM nephritis rats, SMemb expression was increased in epithelial cells. In all models examined, mesangial and epithelial expression of SMemb was confirmed by immunoelectron microscopy, and enhanced expression of SMemb mRNA in glomeruli was verified by RNase protection assay. We conclude from these results that glomerular cells change their phenotypes differently depending on various types of glomerular diseases. These phenotypic changes in glomerular cells can be revealed by the combined immunostaining for SMemb and alpha-SM actin. SMemb is especially useful to detect both mesangial and glomerular epithelial cell activation in these glomerular disease models. Understanding the functional difference and regulatory mechanisms of these cytoskeletal proteins will provide insight into the pathogenesis and progression of glomerular diseases.
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PMID:Expression of a nonmuscle myosin heavy chain in glomerular cells differentiates various types of glomerular disease in rats. 873 Oct 86

This study tested the hypothesis that insulin-like growth factor I (IGF-I) expression is increased at sites of fibrosis in diseased intestine of patients with Crohn's disease (CD). IGF-I mRNA was quantified by RNase protection assay in uninvolved and involved intestine of 13 CD patients (10 ileum, 3 colon) and 7 ulcerative colitis (UC) patients (colon). In situ hybridization histochemistry compared the localization of IGF-I and procollagen alpha1(I) mRNAs. Masson's trichrome staining and immunohistochemistry for IGF-I precursor, alpha-smooth muscle actin (A), vimentin (V), desmin (D), and c-kit were used to examine the mesenchymal cell subtypes that express IGF-I and collagen in uninvolved and involved ileum and colon of CD patients and "normal" ileum and colon from noninflammatory controls. IGF-I mRNA was elevated in involved ileum and colon of patients with CD but not in involved colon of patients with UC. IGF-I and procollagen alpha1(I) mRNA showed overlapping distribution within fibrotic submucosa and muscularis propria of involved CD ileum and colon. In involved CD intestine, increased IGF-I precursor expression localized to mesenchymal cells in regions of tissue disorganization and fibrosis in muscularis mucosa, submucosa, and muscularis propria. In these regions, there were increased numbers of V(+) cells relative to normal or uninvolved intestine. Increased IGF-I expression was localized to cells with a phenotype typical of fibroblasts (V(+)/A(-)/D(-)), myofibroblasts (V(+)/A(+)/D(+)), and, to a lesser extent, cells with normal enteric smooth muscle phenotype (V(-)/A(+)/D(+)). We conclude that increased IGF-I expression in multiple mesenchymal cell subtypes and increased numbers of cells with fibroblast/myofibroblast phenotype are involved in fibrosis associated with CD.
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PMID:IGF-I and procollagen alpha1(I) are coexpressed in a subset of mesenchymal cells in active Crohn's disease. 1109 55

Leptin is a 16-kd hormone that mediates a range of metabolic effects by using a transduction pathway from the long form of the leptin receptor, OB-R(L,) through Janus kinase-signal transducer and activator of transcription (Jak-Stat) signaling components. Leptin is produced by hepatic stellate cells (HSCs) but only following their "activation." Because activation of stellate cells is a central event in the fibrotic response to liver injury, we hypothesized that leptin may directly stimulate fibrogenesis in activated stellate cells via OB-R(L). We analyzed leptin receptors and their signaling partners in a stellate cell line (HSC-T6) as well as in primary stellate cell isolates. We also examined the effect of leptin on stellate cell expression of alpha(2)(I) collagen messenger RNA (mRNA) levels by ribonuclease protection analysis (RPA). Finally, we examined the role of leptin in in vivo fibrogenesis by inducing a wounding response in ob/ob mice, which lack functional leptin. HSC-T6 and culture-activated stellate cells expressed OB-R(L). Scatchard analysis verified specific binding of leptin to HSCs, with an association constant (K(d)) equal to 660 +/- 5.8 pmol/L. Exposure of HSCs to leptin resulted in significant increases in alpha(2)(I) collagen mRNA expression. Transient transfection with a promoter reporter construct showed a 3-fold increase in alpha(2)(I) collagen transgene activity. Leptin stimulated activation of Stat3 in activated HSCs. Finally, lean animals, but not ob/ob littermates, had significant fibrosis as assessed by picrosirius red staining and abundant alpha-smooth muscle actin staining. In conclusion, these results indicate that leptin is profibrogenic in activated HSCs and can signal via the Jak-Stat pathway. Up-regulation of leptin signaling in liver injury could contribute to enhanced fibrogenesis, particularly in states in which leptin levels are high.
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PMID:Leptin in hepatic fibrosis: evidence for increased collagen production in stellate cells and lean littermates of ob/ob mice. 1191 21

A pathologically elevated interstitial fluid pressure (IFP) is a characteristic of both clinical and experimental carcinoma. The soluble TGF-beta receptor type II-murine Fc:IgG2A chimeric protein (Fc:TbetaRII) lowers IFP in the KAT-4 experimental model for anaplastic thyroid carcinoma. Analyses of messenger RNA (mRNA) expressions by Affymetrix microarrays and RNase protection assays, as well as of protein expressions identified tumor macrophages as targets for Fc:TbetaRII. Treatment with Fc:TbetaRII reduced albumin extravasation, increased coverage of alpha-smooth muscle actin-positive cells and reduced expression of NG2, a marker of activated pericytes, in KAT-4 carcinoma blood vessels. Specific inhibition of interleukin-1 (IL-1), a major cytokine produced by activated macrophages, lowered carcinoma IFP to a similar degree as Fc:TbetaRII but had no significant effect on the parameters of blood vessel maturation. Neither Fc:TbetaRII nor inhibition of IL-1 changed blood vessel density. Finally, pretreatment of KAT-4 carcinomas with Fc:TbetaRII increased the antitumor efficacy of doxorubicin. Our data emphasize a potential role of tumor macrophages in carcinoma physiology and identify these cells as potential stromal targets for treatment aimed to improve efficacy of chemotherapy.
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PMID:Inhibition of TGF-beta modulates macrophages and vessel maturation in parallel to a lowering of interstitial fluid pressure in experimental carcinoma. 1571 66

Keloid scars represent a pathological response to cutaneous injury under the regulation of many growth factors. Activin-A, a dimeric protein and a member of the transforming growth factor-beta superfamily, has been shown to regulate various aspects of cell growth and differentiation in the repair of the skin mesenchyme and the epidermis. Thus our aim was to study the role of activin and its antagonist, follistatin, in keloid pathogenesis. Increased mRNA expression for activin was observed in keloid scar tissue by performing RNase protection assay. Immunohistochemistry showed increased localization of both activin-A and follistatin in the basal layer of epidermis of keloid tissue compared with normal tissue. ELISA demonstrated a 29-fold increase in concentration of activin-A and an approximately 5-fold increase in follistatin in conditioned media in keloid fibroblasts compared with normal fibroblasts. Although keloid keratinocytes produced 25% more follistatin than normal keratinocytes, the amounts of activin-A, in contrast, was approximately 77% lower. Proliferation of fibroblasts was stimulated when treated with exogenous activin-A (46% increase in keloids fibroblasts) or following co-culture with hbetaAHaCaT cells (66% increase). Activin-A upregulated key extracellular matrix components, namely collagen, fibronectin, and alpha-smooth muscle actin, in normal and keloid fibroblasts. Co-treatment of follistatin with activin-A blocked the stimulatory effects of activin on extracellular matrix components. These findings emphasize the importance of the activin system in keloid biology and pathogenesis and suggest a possible therapeutic potential of follistatin in the prevention and treatment of keloids.
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PMID:The role of the activin system in keloid pathogenesis. 1697 93

This study aimed to investigate a biocompatible, biomechanically functional, small-diameter (<6 mm) scaffold for tissue engineering a vascular graft using acellular porcine ureters. Porcine ureters were decellularized and sterilized using sequential treatment with hypotonic Tris buffer, sodium dodecyl sulphate 0.1% w/v (plus proteinase inhibitors), nuclease solution (RNase and DNase), and peracetic acid. The scaffold was compared with fresh ureter according to histology, immunocytochemistry, quantitative determination of alpha-galactosyl (alpha-Gal), and biochemistry. The biomechanical properties of the scaffold were compared with those of fresh ureters and human saphenous vein. The biocompatibility of decellularized ureters was assessed using in vitro contact and extract cytotoxicity tests. The in vivo biocompatibility was investigated using a mouse model. The histioarchitecture of the acellular ureteric scaffolds was preserved with some loss of basement membrane proteins while showing no evidence of cellularity. There was no evidence of residual alpha-Gal epitope present in acellular ureter. The ultimate tensile strength, compliance, and burst pressures of the acellular ureters were not compromised, compared with fresh tissues (p > 0.05), and the results compared favorably with fresh human saphenous vein samples (p > 0.05). The decellularized scaffolds were shown to be biocompatible with porcine smooth muscle and endothelial cells in vitro. One month after subcutaneous implantation in mice, explants were analyzed immunohistochemically using anti-CD3, Factor VIII, F4/80 (macrophage), and alpha-smooth muscle actin antibodies. The fresh tissue controls had a significantly thicker capsule (of inflammatory cells and fibrous tissue) than decellularized implants (p < 0.05). Decellularized explants were infiltrated with a combination of fibroblast-like cells and macrophages, indicating a healthy repair process. This study has demonstrated the potential of acellular porcine ureteric scaffolds in tissue engineering small-diameter living vascular grafts.
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PMID:Tissue engineering small-diameter vascular grafts: preparation of a biocompatible porcine ureteric scaffold. 1895 Feb 73