Atrial natriuretic-like peptide and its prohormone within metasequoia.

Metasequoia glyptostroboides was one of the dominant conifers in North America, Asia, and Europe for more than 100 million years since the late Cretaceous Albian Age, but Quaternary glaciations drove the Metasequoia population to apparent extinction. A small pocket of Metasequoia, however, was found in central China in the 1940s representing the only surviving population of this "living fossil" species. Atrial natriuretic peptide, a 28-amino-acid peptide hormone that causes sodium and water excretion in animals, has been found to be part of the first peptide hormonal system in lower plants. The existence of this hormonal system has never been examined within trees of any genus. High-performance gel permeation chromatography of the leaves and stems (i.e., branches) of Metasequoia followed by atrial natriuretic peptide radioimmunoassay revealed an ANP-like peptide and its prohormone (i.e., approximately 13,000 mol wt) were present in both leaves and stems of this conifer. The elution profile of ANP-like peptide in stems of Metasequoia had a shoulder to the left of where pure synthetic ANP elutes suggesting the possibility of a slightly larger peptide eluting within this shoulder secondary to alternate processing of the ANP-like prohormone and similar to what occurs with the kidney of animals. The elution profile of ANP-like peptide in the leaves of Metasequoia revealed two peaks; one where ANP elutes and a second peak suggesting a smaller peptide that has been metabolically processed. The presence of the ANP-like prohormone strongly suggests that ANP-like gene expression is occurring in both leaves and stems of Metasequoia since this prohormone is the gene product of this hormonal system. The presence of the ANP-like hormonal system in trees implies that this hormonal system may have been present early in land plant evolution to allow trees to reach heights of greater than 30 feet where a water flow-enhancing substance is absolutely necessary for water flow to occur to these heights.

Directed antisense therapy confirms the role of protein kinase C-alpha in the tumorigenicity of pancreatic cancer.

BACKGROUND: The level of expression of the alpha isoform of protein kinase C (PKC-alpha) has been shown to correlate inversely with the pathologic differentiation of human pancreatic cancers. METHODS: We stably transfected a moderately differentiated pancreatic cell line (HPAC) to overexpress PKC-alpha and examined the survival rates compared with parent HPAC according to an orthotopic model. Next we used a PKC-alpha antisense oligonucleotide specifically to down-regulate this isoform in vitro and examine the effect of treatment in vivo again according to the orthotopic model. RESULTS: Animals implanted with the overexpressing cell line had a mortality rate almost twice that of those implanted with the parent cell line (P < .01). Treatment with antisense oligonucleotide in increasing concentrations down-regulated PKC-alpha mRNA by Northern blot analysis and reverse transcriptase-polymerase chain reaction. Animals treated with antisense oligonucleotide after orthotopic implantation of pancreatic cancer cells survived statistically longer than those treated with vehicle alone (P = .005). Treatment with a scrambled oligonucleotide also conferred a survival benefit compared with vehicle alone (P < .01). CONCLUSIONS: Tumorigenicity of pancreatic cancer is related directly to PKC-alpha expression in vivo as demonstrated by decreased survival when overexpressed. PKC-alpha expression can be down-regulated directly (antisense) and indirectly (scrambled) in vitro, which subsequently confers a dramatic survival benefit in vivo.

Tissue-specific cytokine production during experimental acute pancreatitis. A probable mechanism for distant organ dysfunction.

Our purpose was to determine if cytokines are produced systemically during acute pancreatitis. Proinflammatory cytokines are elevated during acute pancreatitis and have been implicated in the progression of pancreatitis-associated multiple organ dysfunction. Whether these mediators are produced within all tissues or very few specific organs is not known. Edematous pancreatitis was induced in adult male mice by IP injection of cerulein. Necrotizing pancreatitis was induced in young female mice by feeding a choline-deficient, ethionine supplemented diet. Animals were sacrificed as pancreatitis worsened, with multiple organs prepared for tissue mRNA and protein analysis by RT-PCR and immunoblotting. Pancreatitis severity was established by histologic grading and serum amylase and lipase. There was no cytokine mRNA or protein detectable prior to the induction of pancreatitis. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1 beta) mRNA and protein were detected within the pancreas early in the course of pancreatitis in both models, coinciding with the development of hyperamylasemia (both P < 0.001). Interleukin-6 was produced in the pancreas after pancreatitis was more fully developed (P < 0.001). IL-1 beta and TNF-alpha were subsequently produced in large amounts in lung, liver, and spleen but never within kidney, cardiac muscle, or skeletal muscle. A significant delay between pancreatic and distant organ cytokine production was always observed. It is concluded that proinflammatory cytokines are produced within the pancreas and within organs known to develop dysfunction during severe pancreatitis. Cytokine production is tissue specific, correlates with disease severity, and occurs within the pancreas first and subsequently within distant organs.

Decreased mortality of severe acute pancreatitis after proximal cytokine blockade.

OBJECTIVE: This study determined the ability of interleukin-1 receptor antagonist (IL-1ra) to decrease the mortality of experimental acute pancreatitis. The response of the inflammatory cytokine cascade and its subsequent effects on pancreatic morphology were measured to determine the role of these peptides in mediating pancreatic injury. SUMMARY BACKGROUND DATA: Previous studies have shown that proinflammatory cytokines are produced in large amounts during acute pancreatitis and that blockade at the level of the IL-1 receptor significantly decreases intrinsic pancreatic damage. The subsequent effect on survival is not known. METHODS: A lethal form of acute hemorrhagic necrotizing pancreatitis was induced in young female mice by feeding a choline-deficient, ethionine supplemented (CDE) diet for 72 hours. For determination of mortality, the animals were divided into 3 groups of 45 animals each: control subjects received 100/microL normal saline intraperitoneally every 6 hours for 5 days; IL-1ra early mice received recombinant interleukin-1 receptor antagonist 15 mg/kg intraperitoneally every 6 hours for 5 days beginning at time 0; IL-1ra late mice received IL-1ra 15 mg/kg intraperitoneally every 6 hours for 3.5 days beginning 1.5 days after introduction of the CDE diet. A parallel experiment was conducted simultaneously with a minimum of 29 animals per group, which were sacrificed daily for comparisons of serum amylase, lipase, IL-1, IL-6, tumor necrosis factor-alpha, IL-1ra, pancreatic wet weight, and blind histopathologic grading. RESULTS: The 10-day mortality in the untreated control group was 73%. Early and late IL-1ra administration resulted in decreases of mortality to 44% and 51%, respectively (both p < 0.001). Interleukin-1 antagonism also was associated with a significant attenuation in the rise in pancreatic wet weight and serum amylase and lipase in both early and late IL-1ra groups (all p < 0.05). All control animals developed a rapid elevation of the inflammatory cytokines, with maximal levels reached on day 3. The IL-1ra-treated animals, however, demonstrated a blunted rise of these mediators (all p < 0.05). Blind histologic grading revealed an overall decrease in the severity of pancreatitis in those animals receiving the antagonist. CONCLUSIONS: Early or late blockade of the cytokine cascade at the level of the IL-1 receptor significantly decreases the mortality of severe acute pancreatitis. The mechanism by which this is accomplished appears to include attenuation of systemic inflammatory cytokines and decreased pancreatic destruction.

Atrial natriuretic peptides are present throughout the plant kingdom and enhance solute flow in plants.

The present investigation was designed to 1) determine if atrial natriuretic-like peptides are present throughout the plant kingdom and 2) to determine if these peptides increase the flow of solute and/or water upward to leaves and flowers of plants. The 126-amino acid prohormone of atrial natriuretic factor (proANF)-(1-30), proANF-(31-67), and atrial natriuretic factor (ANF)-like peptides were present in the roots, stems, leaves, and flower petals of the more highly developed plants (Tracheophyta), with their highest concentrations being: Florida beauty > buddhist pine > Boston fern > rose = geranium = resurrection plant or club moss > Moses-in-the-cradle > Florida coontie. These peptides were also present in Bryophata (plants without vascular tissue or roots) and even in Euglena, flagellated chlorophyll-containing plants without leaves, stems, or roots. proANF-(1-30), proANF-(31-67), and proANF-(79-98) but not ANF (each at < 5.9 pg/ml) significantly increased (P < 0.001) the flow of colored water up stems, coloring their flowers 15-35 min earlier than the other one-half of the same flowers without exogenous peptide addition. These same peptides increased the rate of transpiration (i.e., loss of water from the leaves) and the absorption of solutions. High-performance gel permeation chromatography revealed that proANF-(1-30), proANF-(31-67), and ANF extracted from plants are very similar to their pure synthetic human sequences, with elution profiles and molecular weights of the plant extracts duplicating those of the pure synthetic peptides.