The complete 1,210-amino acid sequence of the human epidermal growth factor (EGF) receptor precursor, deduced from cDNA clones derived from placental and A431 carcinoma cells, reveals close similarity between the entire predicted v-erb-B mRNA oncogene product and the receptor transmembrane and cytoplasmic domains. A single transmembrane region of 23 amino acids separates the extracellular EGF binding and cytoplasmic domains. The receptor gene is amplified and apparently rearranged in A431 cells, generating a truncated 2.8-kilobase mRNA which encodes only the extracellular EGF binding domain.

Human tumour necrosis factor has about 30% homology in its amino acid sequence with lymphotoxin, a lymphokine that has similar biological properties. Recombinant tumour necrosis factor can be obtained by expression of its complementary DNA in Escherichia coli and induces the haemorrhagic necrosis of transplanted methylcholanthrene-induced sarcomas in syngeneic mice.

Kirsten (Ki)-ras cDNA clones were prepared from human lung and colon carcinoma cell lines expressing an activated c-Ki-ras2 gene. DNA sequence analysis and transfection studies indicate that different point mutations at the same codon can activate the gene; that most human c-Ki-ras2 mRNA uses sequences from a fourth coding exon distinct from that of its viral counterpart; and that at least one cell line is functionally homozygous for the activated gene.

Hereditary hypogonadism in the hypogonadal (hpg) mouse is caused by a deletional mutation of at least 33.5 kilobases encompassing the distal half of the gene for the common biosynthetic precursor of gonadotropin-releasing hormone (GnRH) and GnRH-associated peptide (GAP). The partially deleted gene is transcriptionally active as revealed by in situ hybridization histochemistry of hpg hypothalamic tissue sections, but immunocytochemical analysis failed to show the presence of antigen corresponding to any part of the precursor protein.

P110delta phosphoinositide 3-kinase (PI3K) plays a pivotal role in the recruitment and activation of certain inflammatory cells. Recent findings revealed that the activity of p110delta also contributes to allergen-IgE-induced mast cell activation and vascular permeability. We investigated the role of p110delta in allergic airway inflammation and hyperresponsiveness using IC87114, a selective p110delta inhibitor, in a mouse asthma model. BALB/c mice were sensitized with OVA and, upon OVA aerosol challenge, developed airway eosinophilia, mucus hypersecretion, elevation in cytokine and chemokine levels, up-regulation of ICAM-1 and VCAM-1 expression, and airway hyperresponsiveness. Intratracheal administration of IC87114 significantly (P<0.05) attenuated OVA-induced influx into lungs of total leukocytes, eosinophils, neutrophils, and lymphocytes, as well as levels of IL-4, IL-5, IL-13, and RANTES in a dose-dependent manner. IC87114 also significantly (P<0.05) reduced the serum levels of total IgE and OVA-specific IgE and LTC(4) release into the airspace. Histological studies show that IC87114 inhibited OVA-induced lung tissue eosinophilia, airway mucus production, and inflammation score. In addition, IC87114 significantly (P<0.05) suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. Western blot analyses of whole lung tissue lysates shows that IC87114 markedly attenuated the OVA-induced increase in expression of IL-4, IL-5, IL-13, ICAM-1, VCAM-1, RANTES, and eotaxin. Furthermore, IC87114 treatment markedly attenuated OVA-induced serine phosphorylation of Akt, a downstream effector of PI3K signaling. Taken together, our findings implicate that inhibition of p110delta signaling pathway may have therapeutic potential for the treatment of allergic airway inflammation.

The phosphoinositide 3-kinase (PI3K) catalytic subunit p110␦ is expressed in neutrophils and is thought to play a role in their accumulation at sites of inflammation by contributing to chemoattractantdirected migration. We report here that p110␦ is present in endothelial cells and participates in neutrophil trafficking by modulating the proadhesive state of these cells in response to tumor necrosis factor ␣ (TNF␣). Specifically, administration of the selective inhibitor of PI3K␦, IC87114, to animals reduced neutrophil tethering to and increased rolling velocities on cytokine-activated microvessels in a manner similar to that observed in mice deficient in p110␦. These results were confirmed in vitro as inhibition of this isoform in endothelium, but not neutrophils, diminished cell attachment in flow. A role for PI3K␦ in TNF␣-induced signaling is demonstrated by a reduction in Aktphosphorylation and phosphatidylinositol-dependent kinase 1 (PDK1) enzyme activity upon treatment of this cell type with IC87114. p110␦ expressed in neutrophils also contributes to trafficking as demonstrated by the impaired movement of these cells across inflamed venules in animals in which this catalytic subunit was blocked or genetically deleted, results corroborated in transwell migration assays. Thus, PI3K␦ may be a reasonable therapeutic target in specific inflammatory conditions as blockade of its activity reduces neutrophil influx into tissues by diminishing their attachment to and migration across vascular endothelium. (Blood.

Cloned cDNAs encoding the precursor protein for gonadotropin-releasing hormone (Gn-RH) and prolactin release-inhibiting factor (PIF) were isolated from libraries derived from human and rat hypothalamic mRNA. Nucleotide sequence analyses predict precursor proteins of 92 amino acids for both species and show identity between the human placental and human hypothalamic precursor proteins. Whereas the Gn-RH peptide structure is completely conserved in human and rat, the PIF domain of the precursor displays 70% interspecies homology. Genomic analyses revealed the presence of a single Gn-RH-PIF gene in human and rat containing sequences corresponding to the cDNA distributed across four exons.The decapeptide gonadotropin-releasing hormone (Gn-RH), also termed luteinizing hormone-releasing hormone (LH-RH), is a key molecule in the control of mammalian reproduction (1, 2). The peptide is secreted in a pulsatile manner from hypothalamic neurons into the capillary plexus of the median eminence to elicit the episodic release of gonadotropins from the anterior pituitary. In addition to the role of Gn-RH on pituitary gonadotrophs, Gn-RH or Gn-RH-like immunoreactivity has been found in extrahypothalamic regions of the central nervous system (3), gonads (4), mammary glands (5), and placenta (6), indicating that the decapeptide serves a variety of other functions essential for reproduction.In an attempt to study the biosynthesis of Gn-RH we recently reported the use of oligonucleotide probes to isolate a recombinant X phage carrying human genomic DNA that contained coding sequence for Gn-RH and the subsequent use of this DNA in the isolation of cloned human placental cDNA encoding a 92 amino acid precursor protein for Gn-RH (7). The placental protein, whose structure was solely deduced from nucleotide sequencing, contains an enzymatic processing site that separates the Gn-RH structure from a 56 amino acid sequence initially termed GAP for "Gn-RHassociated peptide." Immunocytochemical studies revealed antigenic determinants of this peptide in rat brain. In fact, such antigenic determinants were found by us in Gn-RH containing neurons only and coexisted with Gn-RH in secretory granules of nerve terminals in the median eminence (8).The 56 amino acid peptide synthesized by genetically programed Escherichia coli effected gonadotropin release similar to Gn-RH and possessed potent prolactin secretion inhibitory action when tested in vitro by using primary rat anterior pituitary cell cultures (9). Active immunization with synthetic peptides derived from the 56 amino acid sequence led to greatly increased serum levels of prolactin in rabbits (9). These findings identified the 56 amino acid sequence as a dominant prolactin secretion-inhibitory factor (PIF) and demonstrated that the hypothalamic control of gonadotropin and prolactin secretion is coupled through the synthesis of a common precursor for Gn-RH and PIF by neurosecretory cells (9). This concept assumes that the same precursor protein is biosynthesized in placenta and hypo...

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