A heparin-binding growth factor secreted by macrophage-like cells that is related to EGF.

Macrophage-like U-937 cells secrete a 22-kilodalton heparin-binding growth factor that is mitogenic for BALB-3T3 fibroblasts and smooth muscle cells, but not endothelial cells. The amino acid sequence predicted from complementary DNA clones indicates that the mitogen is a new member of the epidermal growth factor (EGF) family. This heparin-binding EGF-like growth factor (HB-EGF) binds to EGF receptors on A-431 epidermoid carcinoma cells and smooth muscle cells, but is a far more potent mitogen for smooth muscle cells than is EGF. HB-EGF is also expressed in cultured human macrophages and may be involved in macrophage-mediated cellular proliferation.

Nucleotide sequence of a bovine clone encoding the angiogenic protein, basic fibroblast growth factor.

Basic and acidic fibroblast growth factors (FGF's) are potent mitogens for capillary endothelial cells in vitro, stimulate angiogenesis in vivo, and may participate in tissue repair. An oligonucleotide probe for bovine basic FGF was designed from the nucleotide sequence of the amino-terminal exon of bovine acidic FGF, taking into account the 55 percent amino acid sequence homology between the two factors. With this oligonucleotide probe, a full length complementary DNA for basic FGF was isolated from bovine pituitary. Basic FGF in bovine hypothalamus was shown to be encoded by a single 5.0-kilobase messenger RNA; in a human hepatoma cell line, both 4.6- and 2.2-kilobase basic FGF messenger RNA's were present. Both growth factors seem to be synthesized with short amino-terminal extensions that are not found on the isolated forms for which the amino acid sequences have been determined. Neither basic nor acidic FGF has a classic signal peptide.

Addition of growth hormone secretion signal to basic fibroblast growth factor results in cell transformation and secretion of aberrant forms of the protein.

Basic fibroblast growth factor (bFGF) is a potent mitogen for a wide variety of cell types. Unlike most growth factors, the primary translation product for bFGF appears to lack a secretory signal peptide. To explore the normal mode of bFGF release, as well as to investigate the growth factor's oncogenic potential, expression vectors were created for a bFGF cDNA and for a chimeric molecule in which the bFGF coding sequence was linked to the human growth hormone signal peptide sequence. Transfection of NIH3T3 cells with the bFGF cDNA vectors caused the synthesis of high levels of biologically active, cell-associated bFGF, but no evidence of transformation was detected. In contrast, the chimeric bFGF-signal peptide expression vector induced foci of transformation at a very high frequency. The transformed cells grew in soft agar and were tumorigenic in nude mice. The majority of the immunoreactive bFGF species made by the transformed cells was found in the conditioned medium and appeared to be posttranslationally modified, indicating that the chimeric bFGF-signal peptide molecule was processed through the secretory pathway. The secreted bFGF exhibited little mitogenic activity, suggesting that interaction of bFGF with its receptor likely occurs while the fusion protein is being processed along the secretory pathway.

Basic fibroblast growth factor stimulation of epidermal wound healing in pigs.

Basic fibroblast growth factor (bFGF) has recently been shown to be a mitogen for keratinocytes. This observation has now been extended in a porcine model of epidermal wound healing. A single application of recombinant human bFGF given at the time of injury to healthy animals accelerated the rate of epithelialization by 20%; multiple applications gave no greater effect than the single application. Histologic analysis of biopsies of these partial-thickness wounds taken during bFGF-mediated healing supported the assessment of an enhanced rate of epithelialization and an earlier onset of dermal healing. Because no histologic abnormalities were observed, bFGF induced an acceleration of what appears to be the normal healing process.

Basic fibroblast growth factor: production and growth stimulation in cultured adrenal cortex cells.

Cultured bovine adrenal cortex cells express the basic fibroblast growth factor (bFGF) gene and contain, but under normal conditions apparently do not release, bFGF. However, once released, bFGF can stimulate proliferation of the cells, indicating that it could act as a self-stimulating growth factor for adrenal cortex cells. It is conceivable that the intracellular bFGF is released upon injury of the adrenal cortex and that it may be involved in the subsequent tissue repair mechanisms by stimulating the proliferation of adrenal cortical and vascular endothelial cells.

Effect of local application of the antimicrobial peptide IB-367 on the incidence and severity of oral mucositis in hamsters.

OBJECTIVE: The purpose of this animal study was to determine whether IB-367, an antimicrobial peptide, is able to ameliorate oral mucositis by reducing microflora densities on the mucosal surfaces of the mouth. STUDY DESIGN: Oral mucositis was induced in hamsters by intraperitoneal injection of 5-fluorouracil followed by superficial abrasion of the buccal mucosa. A test formulation was applied topically to the buccal mucosa 5 or 6 times per day starting 6 to 8 hours before abrasion. RESULTS: Mucositis scores were significantly lower (P < .05) in hamsters given formulations containing 0.5 or 2.0 mg/mL of IB-367 than in placebo-treated controls. Treatment with IB-367 produced a more than 100-fold reduction in oral microflora densities. In a second experiment, treatment of hamsters with a formulation containing IB-367 at 0.12, 0.5 or 2.0 mg/mL resulted in a dose-dependent reduction in mucositis severity. CONCLUSION: The results indicate that reduction of local microflora densities through use of IB-367 may improve clinical outcomes in patients at risk for the development of oral mucositis.

Protegrin antimicrobial peptides.

Protegrins are 16 to 18 amino acid, cationic antimicrobial peptides that are produced by porcine neutrophils, and are activated extracellularly by cleavage of the pro-protegrin molecule by neutrophil elastase. Biologically, the protegrins are characterized by broad-spectrum antimicrobial activity, rapid microbicidal action and low inherent ability to induce microbial resistance.Structurally, the protegrins form amphiphilic beta-sheets maintained by two intramolecular disulfides that are key for optimal biological activity. A synthetic protegrin analog, IB-367, is in clinical development as a locally administered agent in one program to prevent oral mucositis, a significant side effect of high dose chemotherapy and radiotherapy, and in another program to prevent nosocomial pneumonia in patients undergoing mechanically assisted ventilation.

Nucleotide sequence of the J gene and surrounding untranslated regions of phage G4 DNA: comparison with phage phiX174.

A 290 nucleotide long region of the bacteriophage G4 genome including the end of the overlapping genes D and E, the entire gene J and the untranslated region between genes J and F has been sequenced and compared with the same region in bacteriophage phiX174. Deletions, insertions, duplications and single base changes in G4 relative to phiX174 have resulted in the following changes: the loss of the phiX174 overlapping gene Dtermination and gene J initiation codons, resulting in their separation by 32 untranslated nucleotides; the deletion of one third of the gene J coding region, so that the G4 protein is only 24 amino acids long compared with 37 amino acids in phiX174; and the establishment of a long untranslated region between G4 genes J and F, which despite many nucleotide changes retains the ability to form a stable hairpin loop in the same place and with the same geometry as in phiX174. The G4 overlapping gene E is longer than in phiX174 and extends beyond gene D. Sixteen nucleotides at the end of genes D and E in phiX174 are duplicated in G4 before gene J.

The gene encoding the common alpha subunit of the four human glycoprotein hormones.

The gene encoding the common alpha subunit of the four human glycoprotein hormones, chorionic gonadotropin (CG), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH), has been cloned in a bacteriophage lambda vector. Restriction endonuclease digestion of total human DNA suggests that the common alpha subunit is coded for by a single gene. Three distinct polymorphic hybridization patterns have been observed for this gene in the human population. The cloned gene encompasses a total of 9.4 kilobases (kb) and contains three intervening sequences whose locations have been established by restriction enzyme mapping and by DNA sequencing. One of the intervening sequences is located in the 5' untranslated region, generating a leader sequence that is separated from the rest of the gene by 6.4 kb. The other two intervening sequences are 1.7 and 0.4 kb long and are located within codon number 6, and between codons 67 and 68, respectively. The location of the 5' end of the mature transcript has been established by priming placental mRNA with a restriction fragment obtained from the cloned cDNA. A transcript of similar size for the alpha subunit gene has been detected in both the pituitary, where the gene is expressed for the synthesis of LH, FSH, and TSH, and the placenta, where the gene is expressed for the synthesis of CG. When parts of the 5' untranslated nucleotide sequences of the alpha subunit and the human growth hormone genes are compared a highly homologous region is observed. These otherwise unrelated genes share the common feature that they encode a secreted pituitary polypeptide hormone.

Isolation, cloning and sequence analysis of the cDNA for the alpha-subunit of human chorionic gonadotropin.

A 621-base pair fragment of the cDNA for the alpha-subunit of human chorionic gonadotropin has been isolated by cloning in a plasmid vector, and the complete nucleotide sequence determined. The entire coding region, including the 24-amino acid pre-sequence and most of the untranslated regions, are present in the fragment.

The cDNA for the beta-subunit of human chorionic gonadotropin suggests evolution of a gene by readthrough into the 3'-untranslated region.

A 579-base pair approximately full-length cDNA which codes for the 145-amino acid long beta-subunit of human chorionic gonadotropin (HCG) has been cloned in the plasmid vector pBR322 and its complete nucleotide sequence determined. A hydrophobic presequence of 20 amino acids can be identified from the nucleotide sequence. The amino acid sequence of the beta-subunit is known to be related to those of the beta-subunits of the other glycoprotein hormones LH, FSH and TSH, but the beta-subunit of HCG is unique in that it contains a C-terminal extension of about 30 amino acids which has no homologous counterpart in the other three hormones. Analysis of the beta HCG cDNA nucleotide sequence suggests that this extension may have arisen by the loss of the termination codon of an ancestral beta-like gene so that most of what was previously the 3'-untranslated region now codes for protein. The beta-subunit of HCG terminates with the codon UAA located 16 bases before the poly(A) in the sequence AAUAAA. This sequence is believed to be a recognition signal involved in either polyadenylation or processing and therefore has a dual role in this gene, serving both a coding and a regulatory function.