Coagulation factors promote brown adipose tissue dysfunction and abnormal systemic metabolism in obesity

Brown adipose tissue (BAT) has a role in maintaining systemic metabolic health in rodents and humans. Here, we show that metabolic stress induces BAT to produce coagulation factors, which then-together with molecules derived from the circulation-promote BAT dysfunction and systemic glucose intolerance. When mice were fed a high-fat diet (HFD), the levels of tissue factor, coagulation Factor VII (FVII), activated coagulation Factor X (FXa), and protease-activated receptor 1 (PAR1) expression increased significantly in BAT. Genetic or pharmacological suppression of coagulation factor-PAR1 signaling in BAT ameliorated its whitening and improved thermogenic response and systemic glucose intolerance in mice with dietary obesity. Conversely, the activation of coagulation factor-PAR1 signaling in BAT caused mitochondrial dysfunction in brown adipocytes and systemic glucose intolerance in mice fed normal chow. These results indicate that BAT produces endogenous coagulation factors that mediate pleiotropic effects via PAR1 signaling under metabolic stress.

Proteomic analysis of nascent polypeptide chains that potentially induce translational pausing during elongation

Currently, proteins equipped with "ribosomal arrest peptides" (RAPs) that regulate the expression of downstream genes and their own activity by pausing their own translation during elongation are extensively studied. However, studies focusing on RAP have been conducted primarily in prokaryotic cells; studies on eukaryotic cells, especially mammalian cells, are limited. In the present study, we comprehensively examined translationally arrested nascent polypeptides to gain novel insights into RAPs in mammalian cells. Cetyltrimethylammonium bromide was used to obtain nascent polypeptide chains that were translationally arrested during translation elongation. After proteomic analysis, additional screening by discriminating according to amino acid residues at the C-terminal end revealed several novel RAP candidates. Our method can be applied for comprehensive RAP studies in mammalian cells.

Distinct RNA polymerase transcripts direct the assembly of phase-separated DBC1 nuclear bodies in different cell lines

The mammalian cell nucleus is a highly organized organelle that contains membrane-less structures referred to as nuclear bodies (NBs). Some NBs carry specific RNA types that play architectural roles in their formation. Here, we show two types of RNase-sensitive DBC1-containing NBs, DBC1 nuclear body (DNB) in HCT116 cells and Sam68 nuclear body (SNB) in HeLa cells, that exhibit phase-separated features and are constructed using RNA polymerase I or II transcripts in a cell type–specific manner. We identified additional protein components present in DNB by immunoprecipitation–mass spectrometry, some of which (DBC1 and heterogeneous nuclear ribonucleoprotein L [HNRNPL]) are required for DNB formation. The rescue experiment using the truncated HNRNPL mutants revealed that two RNA-binding domains and intrinsically disordered regions of HNRNPL play significant roles in DNB formation. All these domains of HNRNPL promote in vitro droplet formation, suggesting the need for multivalent interactions between HNRNPL and RNA as well as proteins in DNB formation.

LYAR potentiates rRNA synthesis by recruiting BRD2/4 and the MYST-type acetyltransferase KAT7 to rDNA

Activation of ribosomal RNA (rRNA) synthesis is pivotal during cell growth and proliferation, but its aberrant upregulation may promote tumorigenesis. Here, we demonstrate that the candidate oncoprotein, LYAR, enhances ribosomal DNA (rDNA) transcription. Our data reveal that LYAR binds the histone-associated protein BRD2 without involvement of acetyl-lysine-binding bromodomains and recruits BRD2 to the rDNA promoter and transcribed regions via association with upstream binding factor. We show that BRD2 is required for the recruitment of the MYST-type acetyltransferase KAT7 to rDNA loci, resulting in enhanced local acetylation of histone H4. In addition, LYAR binds a complex of BRD4 and KAT7, which is then recruited to rDNA independently of the BRD2-KAT7 complex to accelerate the local acetylation of both H4 and H3. BRD2 also helps recruit BRD4 to rDNA. By contrast, LYAR has no effect on rDNA methylation or the binding of RNA polymerase I subunits to rDNA. These data suggest that LYAR promotes the association of the BRD2-KAT7 and BRD4-KAT7 complexes with transcription-competent rDNA loci but not to transcriptionally silent rDNA loci, thereby increasing rRNA synthesis by altering the local acetylation status of histone H3 and H4.

Progerin impairs vascular smooth muscle cell growth via the DNA damage response pathway

Mutations of the lamin A gene cause various premature aging syndromes, including Hutchinson-Gilford progeria syndrome (HGPS) and atypical Werner syndrome. In HGPS (but not atypical Werner syndrome), extensive loss of vascular smooth muscle cells leads to myocardial infarction with premature death. The underlying mechanisms how single gene mutations can cause various phenotypes are largely unknown. We performed an interactome analysis using mutant forms of lamin A involved in progeroid syndromes. We found that the mutant lamin A responsible for HGPS, known as progerin, could not bind to proteins related to the DNA damage response, including DNA-dependent protein kinase (DNA-PK). In contrast, wild-type lamin A and lamin A mutants causing atypical Werner syndrome were able to bind to these molecules. We also found that forced expression of progerin in vascular smooth muscle cells led to activation of DNA-PK and cellular growth arrest, while knockdown of DNA-PK attenuated this. Deletion of p53 also improved the inhibition of cell growth due to forced expression of progerin. These findings suggested that progerin activates the DNA damage response pathway and that dysregulation of this pathway may be responsible for the development of cardiovascular pathology in patients with HGPS.

Hyperactive mTOR induces neuroendocrine differentiation in prostate cancer cell with concurrent up-regulation of IRF1

BACKGROUND

Neuroendocrine-differentiated prostate cancer (NEPCa) is refractory to androgen deprivation therapy and shows a poor prognosis. The underlying mechanisms responsible for neuroendocrine differentiation (NED) are yet to be clarified. In this study, we investigated the role of mammalian target of rapamycin (mTOR) in NEPCa.

METHODS

We utilized a gain-of-function analysis by establishing a human PCa LNCaP stable line that expresses hyperactive mTOR (LNCaP-mTOR). Then, we employed a comprehensive mass spectrometric analysis to identify a key transcription factor in LNCaP-mTOR, followed by a loss-of-function analysis using CRISPR/Cas system.

RESULTS

The activation of mTOR induced NED. We observed significant cell growth arrest in NED of LNCaP-mTOR, which accompanied increased expression of p21^WAF1/CIP1 . A comprehensive mass spectrometric analysis identified interferon regulatory factor 1 (IRF1) as a key transcription factor in growth arrest of LNCaP-mTOR. The disruption of IRF1 gene in LNCaP-mTOR reversed cell growth arrest along with the suppression of its target p21^WAF1/CIP1 . These results indicate that the growth arrest in NED is at least in part dependent on IRF1 through the induction of p21^WAF1/CIP1 .

CONCLUSIONS

We identified active mTOR as a novel inducer of NED, and elucidated a mechanism underlying the malignant transformation of NEPCa by recapitulating NED in vitro.

Abstract A04: Hyperactive mTOR induces neuroendocrine differentiation in LNCaP prostate cancer cell with concurrent upregulation of interferon regulatory factor 1

The PI3K-Akt-mTOR pathway is frequently activated in prostate cancer. However, the precise function of mTOR in prostate cancer progression is yet to be elucidated. Thus, in this study, we performed a gain-of-function analysis by establishing human prostate cancer LNCaP stable line that expresses hyperactive mTOR (LNCaP-mTOR). Hyperactive mTOR induced neuroendocrine differentiation (NED) that can be suppressed by an mTOR inhibitor, rapamycin. Subsequent comprehensive mass spectrometric analysis in conjunction with cascade analysis indicates that the members of interferon regulator factor (IRF) family, especially IRF1, are key transcription factors in NED of LNCaP-mTOR. Aside from its major role in immune response, IRF1 is known to be a tumor suppressor. To further investigate the function of IRF1 in NED induced by hyperactive mTOR, we disrupted the IRF1 gene in LNCaP-mTOR by CRISPR/Cas system. The disruption of the IRF1 gene resulted in an acceleration of an NED-associated morphological change, elevation of neuroendocrine cell marker, neuron specific enolase, and a partial recovery of growth arrest. These results suggest that IRF1 partially suppresses NED at downstream of hyperactive mTOR. Together, our results indicate that two seemingly contradictory events, NED and the induction of IRF1, are induced by hyperactive mTOR, giving rise to a notion that pharmacological inhibition of mTOR can be a “double-edged sword” for prostate cancer treatments.

Citation Format: Mayuko Kanayama, Toshiya Hayano, Tatsuya Maeda, Shigeo Horie, Atsu Aiba. Hyperactive mTOR induces neuroendocrine differentiation in LNCaP prostate cancer cell with concurrent upregulation of interferon regulatory factor 1. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr A04.

Human nucleolar protein Nop52 (RRP1/NNP-1) is involved in site 2 cleavage in internal transcribed spacer 1 of pre-rRNAs at early stages of ribosome biogenesis

During the early steps of ribosome biogenesis in mammals, the two ribosomal subunits 40S and 60S are produced via splitting of the large 90S pre-ribosomal particle (90S) into pre-40S and pre-60S pre-ribosomal particles (pre-40S and pre-60S). We previously proposed that replacement of fibrillarin by Nop52 (RRP1/NNP-1) for the binding to p32 (C1QBP) is a key event that drives this splitting process. However, how the replacement by RRP1 is coupled with the endo- and/or exo-ribonucleolytic cleavage of pre-rRNA remains unknown. In this study, we demonstrate that RRP1 deficiency suppressed site 2 cleavage on ITS1 of 47S/45S, 41S and 36S pre-rRNAs in human cells. RRP1 was also present in 90S and was localized in the dense fibrillar component of the nucleolus dependently on active RNA polymerase I transcription. In addition, double knockdown of XRN2 and RRP1 revealed that RRP1 accelerated the site 2 cleavage of 47S, 45S and 41S pre-rRNAs. These data suggest that RRP1 is involved not only in competitive binding with fibrillarin to C1QBP on 90S but also in site 2 cleavage in ITS1 of pre-rRNAs at early stages of human ribosome biogenesis; thus, it is likely that RRP1 integrates the cleavage of site 2 with the physical split of 90S into pre-40S and pre-60S.

Comparative proteomic analysis reveals differentially expressed proteins in Caenorhabditis elegans pgl-1 mutants grown at 20°C and 25°C

PGL-1 is an RNA-binding protein component of germ granules and essential for fertility in Caenorhabditis elegans. To clarify the molecular function of PGL-1, we performed comparative proteomic analysis using 2-D DIGE and LC-MS/MS. Five groups of synchronized adult hermaphrodites were analyzed: (1) wild-type N2 grown at 20°C, (2) pgl-1(bn101) mutants grown at 20°C, (3) pgl-1(bn101) mutants grown at 20°C then upshifted to 25°C after the L1 stage, (4) pgl-1(ct131) mutants grown at 20°C, and (5) pgl-1(ct131) mutants grown at 20°C then upshifted to 25°C after the L1 stage. The five groups were divided into two experimental sets for 2-D DIGE: set A included N2 and pgl-1(bn101) mutants, and set B included N2 and pgl-1(ct131) mutants. Dunnett's test indicated 90 and 100 specific spots, respectively, with significantly different expression levels from the rest of the experimental set (q≤0.1). Among them, 69 and 58 spots, respectively, were analyzed by LC-MS/MS. Finally, we identified 19 proteins from 24 specific spots common to both the experimental sets. RNAi analysis indicated that decreased eef-1G expression is strongly associated with the temperature-sensitive sterile phenotype of pgl-1. Our results suggest that PGL-1 is closely involved in translational processes during C. elegans germline development.

Splicing factor 2-associated protein p32 participates in ribosome biogenesis by regulating the binding of Nop52 and fibrillarin to preribosome particles

Ribosome biogenesis starts with transcription of the large ribosomal RNA precursor (47S pre-rRNA), which soon combines with numerous factors to form the 90S pre-ribosome in the nucleolus. Although the subsequent separation of the pre-90S particle into pre-40S and pre-60S particles is critical for the production process of mature small and large ribosomal subunits, its molecular mechanisms remain undetermined. Here, we present evidence that p32, fibrillarin (FBL), and Nop52 play key roles in this separation step. Mass-based analyses combined with immunoblotting showed that p32 associated with 155 proteins including 31 rRNA-processing factors (of which nine were components of small subunit processome, and six were those of RIX1 complex), 13 chromatin remodeling components, and six general transcription factors required for RNA polymerase III-mediated transcription. Of these, a late rRNA-processing factor Nop52 interacted directly with p32. Immunocytochemical analyses demonstrated that p32 colocalized with an early rRNA-processing factor FBL or Nop52 in the nucleolus and Cajal bodies, but was excluded from the nucleolus after actinomycin D treatment. p32 was present in the pre-ribosomal fractions prepared by cell fractionation or separated by ultracentrifugation of the nuclear extract. p32 also associated with pre-rRNAs including 47S/45S and 32S pre-rRNAs. Furthermore, knockdown of p32 with a small interfering RNA slowed the early processing from 47S/45S pre-rRNAs to 18S rRNA and 32S pre-rRNA. Finally, Nop52 was found to compete with FBL for binding to p32 probably in the nucleolus. Given the fact that FBL and Nop52 are associated with pre-ribosome particles distinctly different from each other, we suggest that p32 is a new rRNA maturation factor involved in the remodeling from pre-90S particles to pre-40S and pre-60S particles that requires the exchange of FBL for Nop52.

Parvulin (Par14), a peptidyl-prolyl cis-trans isomerase, is a novel rRNA processing factor that evolved in the metazoan lineage

Although parvulin (Par14/eukaryotic parvulin homolog), a peptidyl-prolyl cis-trans isomerase, is found associated with the preribosomal ribonucleoprotein (pre-rRNP) complexes, its roles in ribosome biogenesis remain undetermined. In this study, we describe a comprehensive proteomics analysis of the Par14-associated pre-rRNP complexes using LC-MS/MS and a knockdown analysis of Par14. Together with our previous results, we finally identified 115 protein components of the complexes, including 39 ribosomal proteins and 54 potential trans-acting factors whose yeast homologs are found in the pre-rRNP complexes formed at various stages of ribosome biogenesis. We give evidence that, although Par14 exists in both the phosphorylated and unphosphorylated forms in the cell, only the latter form is associated with the pre-40 S and pre-60 S ribosomal complexes. We also show that Par14 co-localizes with the nucleolar protein B23 during the interphase and in the spindle apparatus during mitosis and that actinomycin D treatment results in the exclusion of Par14 from the nucleolus. Finally we demonstrate that knockdown of Par14 mRNA decelerates the processing of pre-rRNA to 18 and 28 S rRNAs. We propose that Par14 is a component of the pre-rRNA complexes and functions as an rRNA processing factor in ribosome biogenesis. As the amino acid sequence of Par14 including that in the amino-terminal pre-rRNP binding region is conserved only in metazoan homologs, we suggest that its roles in ribosome biogenesis have evolved in the metazoan lineage.

Automated SPR-LC-MS/MS system for protein interaction analysis

We have developed a novel automated system to analyze protein complexes by integrating a surface plasmon resonance (SPR) biosensor with highly sensitive nanoflow liquid chromatography-tandem mass spectrometry (LC-MS/MS). A His-tagged protein, which is also tagged with FLAG and biotinylated sequences, was expressed in mammalian cells. After purification by using the His tag from the cell lysate, the sample protein mixture was applied to an SPR biosensor and the protein complex was captured on the sensor chip. The automated SPR-LC-MS/MS was then performed: (1) two-step on-chip purification of the protein complex by using the FLAG and the biotinylated tags, (2) on-chip protease digestion of the complex, and (3) online nanoflow LC-MS/MS analysis of the resulting peptide fragments for protein identification. All of these processes could be monitored in real-time by the SPR biosensor. We validated the performance of the system using either FK506-binding protein 52 kDa (FKBP52) or ribosomal protein S19 (rpS19) as bait. Thus, the fully automated SPR-LC-MS/MS system appeared to be a powerful tool for functional proteomics studies, particularly for snapshot analysis of functional cellular complexes and machines.

Evidence for mitochondrial localization of P5, a member of the protein disulphide isomerase family

This report demonstrates for the first time that P5, a member of the protein disulphide isomerase (PDI) family, is present in the mitochondria. Various organelles were screened for proteins bearing the CGHC motif using an affinity column conjugated with the phage antibody 5E, which cross-reacts with PDI family proteins. P5 was found in bovine liver mitochondrial extract and identified by Western blot analysis using anti-P5 antibody and by mass spectrometric analysis. Results of cell fractionation, proteinase sensitivity experiments and immuno-electron microscopy supported the mitochondrial localization of P5 and also indicated the presence of ERp57, another PDI family protein, in mitochondria. Our findings will be useful for the elucidation of the translocation mechanism of PDI family proteins and their roles in mitochondria.

Hsp90 regulates the Fanconi anemia DNA damage response pathway

Heat shock protein 90 (Hsp90) regulates diverse signaling pathways. Emerging evidence suggests that Hsp90 inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG), enhance DNA damage-induced cell death, suggesting that Hsp90 may regulate cellular responses to genotoxic stress. However, the underlying mechanisms are poorly understood. Here, we show that the Fanconi anemia (FA) pathway is involved in the Hsp90-mediated regulation of genotoxic stress response. In the FA pathway, assembly of 8 FA proteins including FANCA into a nuclear multiprotein complex, and the complex-dependent activation of FANCD2 are critical events for cellular tolerance against DNA cross-linkers. Hsp90 associates with FANCA, in vivo and in vitro, in a 17-AAG-sensitive manner. Disruption of the FANCA/Hsp90 association by cellular treatment with 17-AAG induces rapid proteasomal degradation and cytoplasmic relocalization of FANCA, leading to impaired activation of FANCD2. Furthermore, 17-AAG promotes DNA cross-linker-induced cytotoxicity, but this effect is much less pronounced in FA pathway-defective cells. Notably, 17-AAG enhances DNA cross-linker-induced chromosome aberrations. In conclusion, our results identify FANCA as a novel client of Hsp90, suggesting that Hsp90 promotes activation of the FA pathway through regulation of intracellular turnover and trafficking of FANCA, which is critical for cellular tolerance against genotoxic stress.

NOP132 is required for proper nucleolus localization of DEAD-box RNA helicase DDX47

Previously, we described a novel nucleolar protein, NOP132, which interacts with the small GTP binding protein RRAG A. To elucidate the function of NOP132 in the nucleolus, we identified proteins that interact with NOP132 using mass spectrometric methods. NOP132 associated mainly with proteins involved in ribosome biogenesis and RNA metabolism, including the DEAD-box RNA helicase protein, DDX47, whose yeast homolog is Rrp3, which has roles in pre-rRNA processing. Immunoprecipitation of FLAG-tagged DDX47 co-precipitated rRNA precursors, as well as a number of proteins that are probably involved in ribosome biogenesis, implying that DDX47 plays a role in pre-rRNA processing. Introduction of NOP132 small interfering RNAs induced a ring-like localization of DDX47 in the nucleolus, suggesting that NOP132 is required for the appropriate localization of DDX47 within the nucleolus. We propose that NOP132 functions in the recruitment of pre-rRNA processing proteins, including DDX47, to the region where rRNA is transcribed within the nucleolus.

Potential roles for ubiquitin and the proteasome during ribosome biogenesis

We have investigated the possible involvement of the ubiquitin-proteasome system (UPS) in ribosome biogenesis. We find by immunofluorescence that ubiquitin is present within nucleoli and also demonstrate by immunoprecipitation that complexes associated with pre-rRNA processing factors are ubiquitinated. Using short proteasome inhibition treatments, we show by fluorescence microscopy that nucleolar morphology is disrupted for some but not all factors involved in ribosome biogenesis. Interference with proteasome degradation also induces the accumulation of 90S preribosomes, alters the dynamic properties of a number of processing factors, slows the release of mature rRNA from the nucleolus, and leads to the depletion of 18S and 28S rRNAs. Together, these results suggest that the UPS is probably involved at many steps during ribosome biogenesis, including the maturation of the 90S preribosome.

A child case of acute right coronary obstruction due to catheter-induced coronary dissection: successful reperfusion without stenting

We report on a 10-year-old child who suffered from acute right coronary obstruction due to catheter-induced coronary dissection. Immediate placement of a perfusion catheter into the obstructed right coronary artery and subsequent overnight reperfusion allowed successful recovery of the right coronary artery lumen without implantation of a stent. Follow-up angiography demonstrated spontaneous regression of the dissected coronary artery and normal right and left ventricular wall motion. The indication of stent implantation should be carefully determined in a child case of iatrogenic coronary dissection because stenting may induce coronary stenosis during growth.

ERp57 binds competitively to protein disulfide isomerase and calreticulin

In this study, we screened for protein disulfide isomerase (PDI)-binding proteins in bovine liver microsomes under strict salt concentrations, using affinity column chromatography. One main band observed using SDS-PAGE was identified as ERp57 (one of the PDI family proteins) by LC-MS/MS analysis. The K(D) value of PDI binding to ERp57 was calculated as 5.46x10(-6)M with the BIACORE system. The interactions between PDI and ERp57 occurred specifically at their a and b domains, respectively. Interestingly, low concentrations of ERp57 enhanced the chaperone activity of PDI, while high concentrations interfered with chaperone activity. On the other hand, ERp57 did not affect the isomerase activity of PDI. Additionally, following pre-incubation of ERp57 with calreticulin (CRT), decreased interactions were observed between ERp57 and PDI, and vice versa. Based on the data, we propose that once ERp57 binds to PDI or CRT, the resultant complex inhibits further interactions. Therefore, ERp57 selectively forms a protein-folding complex with PDI or CRT in ER.

Human fibrillarin forms a sub-complex with splicing factor 2-associated p32, protein arginine methyltransferases, and tubulins alpha 3 and beta 1 that is independent of its association with preribosomal ribonucleoprotein complexes

Fibrillarin (FIB, Nop1p in yeast) is an RNA methyltransferase found not only in the fibrillar region of the nucleolus but also in Cajal bodies. FIB is essential for efficient processing of preribosomal RNA during ribosome biogenesis, although its precise function in this process and its role in Cajal bodies remain uncertain. Here, we demonstrate that the human FIB N-terminal glycine- and arginine-rich domain (residues 1-77) and its spacer region 1 (78-132) interact with splicing factor 2-associated p32 (SF2A-p32) and that the FIB methyltransferase-like domain (133-321) interacts with protein-arginine methyltransferase 5 (PRMT5, Janus kinase-binding protein 1). We also show that these proteins associate with several additional proteins, including PRMT1, tubulin alpha 3, and tubulin beta 1 to form a sub-complex that is principally independent of the association of FIB with preribosomal ribonucleoprotein complexes that co-immunoprecipitate with the sub-complex in human cells expressing FLAG-tagged FIB. Based on the physical association of FIB with SF2A-p32 and PRMTs, as well as the other reported results, we propose that FIB may coordinate both RNA and protein methylation during the processes of ribosome biogenesis in the nucleolus and RNA editing such as small nuclear (nucleolar) ribonucleoprotein biogenesis in Cajal bodies.

Proteomic analysis of human Nop56p-associated pre-ribosomal ribonucleoprotein complexes. Possible link between Nop56p and the nucleolar protein treacle responsible for Treacher Collins syndrome

Nop56p is a component of the box C/D small nucleolar ribonucleoprotein complexes that direct 2'-O-methylation of pre-rRNA during its maturation. Genetic analyses in yeast have shown that Nop56p plays important roles in the early steps of pre-rRNA processing. However, its precise function remains elusive, especially in higher eukaryotes. Here we describe the proteomic characterization of human Nop56p (hNop56p)-associated pre-ribosomal ribonucleoprotein complexes. Mass spectrometric analysis of purified pre-ribosomal ribonucleoprotein complexes identified 61 ribosomal proteins, 16 trans-acting factors probably involved in ribosome biogenesis, and 29 proteins whose function in ribosome biogenesis is unknown. Identification of pre-rRNA species within hNop56p-associated pre-ribosomal ribonucleoprotein complexes, coupled with the known functions of yeast orthologs of the probable trans-acting factors identified in human, demonstrated that hNop56p functions in the early to middle stages of 60 S subunit synthesis in human cells. Interestingly, the nucleolar phosphoprotein treacle, which is responsible for the craniofacial disorder associated with Treacher Collins syndrome, was found to be a constituent of hNop56p-associated pre-rRNP complexes. The association of hNop56p and treacle within the complexes was independent of rRNA integrity, indicating a direct interaction. In addition, the protein compositions of the treacle-associated and hNop56p-associated pre-ribosomal ribonucleoprotein complexes were very similar, suggesting functional similarities between these two complexes with respect to ribosome biogenesis in human cells.

Proteomic snapshot analyses of preribosomal ribonucleoprotein complexes formed at various stages of ribosome biogenesis in yeast and mammalian cells

Proteomic technologies powered by advancements in mass spectrometry and bioinformatics and coupled with accumulated genome sequence data allow a comprehensive study of cell function through large-scale and systematic protein identifications of protein constituents of the cell and tissues, as well as of multi-protein complexes that carry out many cellular function in a higher-order network in the cell. One of the most extensively analyzed cellular functions by proteomics is the production of ribosome, the protein-synthesis machinery, in the nucle(ol)us--the main site of ribosome biogenesis. The use of tagged proteins as affinity bait, coupled with mass spectrometric identification, enabled us to isolate synthetic intermediates of ribosomes that might represent snapshots of nascent ribosomes at particular stages of ribosome biogenesis and to identify their constituents--some of which showed dynamic changes for association with the intermediates at various stages of ribosome biogenesis. In this review, in conjunction with the results from yeast cells, our proteomic approach to analyze ribosome biogenesis in mammalian cells is described.

Proteomics: advanced technology for the analysis of cellular function

Proteomics developed initially from the decade-long study of comprehensive protein visualization on two-dimensional electrophoresis gels has been expanded by mass spectrometry and the growth in searchable sequence databases. Currently, by use of more sophisticated technology such as a combination of multidimensional chromatography and mass spectrometry, thousands of proteins can automatically be identified in a day along with semiquantitative information on differential-protein expression. As with differential gene expression by cDNA-chips, the differential-protein analysis is useful for monitoring and identifying proteins involved in various physiological changes in cells or organisms, although the analysis alone does not necessarily provide information regarding the cause of the change or the function of the proteins. However, proteomics also provides the tools to expand into more sophisticated biochemical approaches, such as the study of protein interactions that can be determined directly by performing a pull-down assay with a bait protein followed by mass spectrometric identification of the bound proteins. Proteomics, thus, is useful for both large-scale surveys of proteins and detailed studies of the functional relationships among the proteins of interest. Certainly this approach can be applicable to the assessment of amino acid adequacy and safety.

Isolation and proteomic characterization of human Parvulin-associating preribosomal ribonucleoprotein complexes

Human parvulin (hParvulin; Par14/EPVH) belongs to the third family of peptidylprolyl cis-trans isomerases that exhibit an enzymatic activity of interconverting the cis-trans conformation of the prolyl peptide bond, and shows sequence similarity to the regulator enzyme for cell cycle transitions, human Pin1. However, the cellular function of hParvulin is entirely unknown. Here, we demonstrate that hParvulin associates with the preribosomal ribonucleoprotein (pre-rRNP) complexes, which contain preribosomal RNAs, at least 26 ribosomal proteins, and 26 trans-acting factors involved in rRNA processing and assembly at an early stage of ribosome biogenesis. Since an amino-terminal domain of hParvulin, which is proposed to be a putative DNA-binding domain, was alone sufficient to associate in principle with the pre-rRNP complexes, the association is probably through protein-RNA interaction. In addition, hParvulin co-precipitated at least 10 proteins not previously known to be involved in ribosome biogenesis. Coincidentally, most of these proteins are implicated in regulation of microtubule assembly or nucleolar reformation during the mitotic phase of the cell. Thus, these results, coupled with the preferential nuclear localization of hParvulin, suggest that hParvulin may be involved in ribosome biogenesis and/or nucleolar re-assembly of mammalian cells.

Phosphorylation-dependent interaction of kinesin light chain 2 and the 14-3-3 protein

The protein 14-3-3 is a key regulator in a cell signaling pathway mediated by protein phosphorylation. To identify the cellular targets of this protein systematically, we have employed a proteomic approach: protein components pulled down from PC12 cells stably expressing a myc-tagged 14-3-3eta isoform were analyzed by means of SDS-PAGE and mass spectrometry. This procedure allowed us to identify more than 30 proteins that include various known and unknown targets of the 14-3-3 protein. Among them are several proteins in the membrane traffic pathway, such as the heavy and light chains (KHC/KIF5B and KLC2) of conventional kinesin, a heterotetrameric mechanochemical motor involved in the ATP-dependent movement of vesicles and organelles along microtubules. Subsequent analysis showed that 14-3-3 directly binds to kinesin heterodimers through interaction with KLC2 and that this interaction is dependent on the phosphorylation of KLC2. Studies on the interaction between 14-3-3 and KLC2 variants expressed in cultured cells coupled with mass spectrometric analysis proved that Ser575 is the site of phosphorylation in KLC2 that is responsible for the in vivo interaction with the 14-3-3 protein. These data add KLC2 to the growing list of 14-3-3 targets, and suggest a role of 14-3-3 in the phosphorylation-regulated cellular transport of vesicles and organelles.

Solution NMR structure of the myosin phosphatase inhibitor protein CPI-17 shows phosphorylation-induced conformational changes responsible for activation

Contractility of vascular smooth muscle depends on phosphorylation of myosin light chains, and is modulated by hormonal control of myosin phosphatase activity. Signaling pathways activate kinases such as PKC or Rho-dependent kinases that phosphorylate the myosin phosphatase inhibitor protein called CPI-17. Phosphorylation of CPI-17 at Thr38 enhances its inhibitory potency 1000-fold, creating a molecular on/off switch for regulating contraction. We report the solution NMR structure of the CPI-17 inhibitory domain (residues 35-120), which retains the signature biological properties of the full-length protein. The final ensemble of 20 sets of NMR coordinates overlaid onto their mean structure with r.m.s.d. values of 0.84(+/-0.22) A for the backbone atoms. The protein forms a novel four-helix, V-shaped bundle comprised of a central anti-parallel helix pair (B/C helices) flanked by two large spiral loops formed by the N and C termini that are held together by another anti-parallel helix pair (A/D helices) stabilized by intercalated aromatic and aliphatic side-chains. Chemical shift perturbations indicated that phosphorylation of Thr38 induces a conformational change involving displacement of helix A, without significant movement of the other three helices. This conformational change seems to flex one arm of the molecule, thereby exposing new surfaces of the helix A and the nearby phosphorylation loop to form specific interactions with the catalytic site of the phosphatase. This phosphorylation-dependent conformational change offers new structural insights toward understanding the specificity of CPI-17 for myosin phosphatase and its function as a molecular switch.

Double ventricular response by a single ventricular extrastimulus to the inner loop of reentry in a patient without apparent heart disease

In a patient without apparent heart disease, a ventricular extrastimulus delivered from the left ventricular apex where the electrogram was recorded 30 ms after the onset of the QRS complex during VT advanced the second QRS complex, but not the first QRS complex. The morphology of the second QRS complex was the same as that of VT. The postpacing interval was the same as the cycle length of the VT. These findings indicated that the site of stimulation was at the inner loop of the reentry circuit of the VT. A ventricular extrastimulus with a shorter coupling interval advanced the first and second QRS complexes, indicating that the ventricle was activated by antidromic and orthodromic activation from the extrastimulus. Radiofrequency ablation at that site of stimulation terminated the VT and no further VT could be induced.

Fast folding of Escherichia coli cyclophilin A: a hypothesis of a unique hydrophobic core with a phenylalanine cluster

Escherichia coli cyclophilin A, a 164 residue globular protein, shows fast and slow phases of refolding kinetics from the urea-induced unfolded state at pH 7.0. Given that the slow phases are independent of the denaturant concentration and may be rate-limited by cis/trans isomerizations of prolyl peptide bonds, the fast phase represents the true folding reaction. The extrapolation of the fast-phase rate constant to 0 M urea indicates that the folding reaction of cyclophilin A is extraordinarily fast and has about 700 s(-1) of the rate constant. Interrupted refolding experiments showed that the protein molecules formed in the fast phase had already been fully folded to the native state. This finding overthrows the accepted view that the fast folding is observed only in small proteins of fewer than 100 amino acid residues. Examination of the X-ray structure of cyclophilin A has shown that this protein has only one unique hydrophobic core (phenylalanine cluster) formed by evolutionarily conserved phenylalanine residues, and suggests that this architecture of the molecule may be responsible for the fast folding behavior.

Assessment of right artrial mapping and P wave-triggered signal-average in patients with paroxysmal atrial fibrillation

To assess right atrial mapping and P wave-triggered signal-averaged electrocardiogram (ECG) in patients with paroxysmal atrial fibrillation (PAF), this study examined right atrial electrograms using atrial mapping and parameters by P wave-triggered signal-averaged ECG in 39 patients without sick sinus syndrome. Subjects were divided into those with PAF (n = 13; 60+/-13 years old) and a control group (n = 26; 49+/-19 years old). The total number of abnormal right atrial electrograms per patient was significantly greater in the PAF group (3.2+/-1.9) than in the control group (1.1+/-0.9; P < .001). The longest duration of right atrial electrogram in the PAF group tended to be greater than that in the control group (P = .06). The filtered P wave duration was significantly longer in the PAF group than in the control group (144+/-21 vs 125+/-14 ms [P < .002]). The values of the root mean square of P wave-triggered signal-averaged ECG 15 ms from the onset (RMSi 15) and 20 ms from the offset (RMSe 20) were significantly lower in the PAF group (1.1+/-0.4 microV, 1.4+/-0.5 microV) than in the control group (1.9+/-1.1 microV [P < .02], 2.1+/-0.9 microV [P < .01]). The total number of right atrial electrograms in patients with RMSi 15 of < or =1.5 microV was significantly greater than in patients with RMSi 15 of >1.5 microV (2.2+/-1.8 vs 1.3+/-1.3 [P < .05]). Thus, the total number of abnormal right atrial electrograms per patient, the total filtered P wave duration, RMSi 15, and RMSe 20 may be good indices of PAF in patients without sick sinus syndrome. RMSi 15 may reflect the total number of the abnormal right atrial electrograms per patient.

A 21-aminosteroid, U-74006F, attenuates endotoxin-induced lung injury in awake sheep

The purpose of the present study was to examine the efficacy of U-74006F, a 21-aminosteroid, on lung dysfunction induced by endotoxaemia in awake sheep with lung lymph fistula and haemodynamic monitoring. We measured pulmonary haemodynamics, lung lymph balance, circulating leucocyte count, arterial blood gas tensions, and levels of thromboxane (Tx) B2 and 6-keto-prostaglandin (PG) F1 alpha in plasma and lung lymph. We performed two experiments. In experiment 1 (n = 6), we intravenously infused Escherichia coli lipopolysaccharide endotoxin (1 microgram/kg) over 30 min and observed the parameters over 5 h. In experiment 2 (n = 6), we pretreated sheep with an intravenous bolus of U-74006F (2 mg/kg) 30 min before the infusion of endotoxin in the same manner of experiment 1, and continuously infused U-74006F (0.5 mg/kg per h) over 5 h after the bolus during the experiment. The U-74006F significantly suppressed the early pulmonary hypertension, the late increase in pulmonary permeability and the elevations of TxB2 and 6-keto-PGF1 alpha levels in plasma and lung lymph during the early period following endotoxaemia, although the compound did not change the time course of leucocytopenia and hypoxaemia. These findings suggest that the administration of U-74006F attenuates the lung dysfunction induced by endotoxaemia in awake sheep.

Interferon-alpha elevates pulmonary blood pressure in sheep--the role of thromboxane cascade

We tested the effect of interferon-alpha on lung function to examine whether interferon-alpha causes some pathophysiological change in the lung. We prepared awake sheep with chronic lung lymph fistula, and measured the pulmonary hemodynamics, lung fluid balance and concentrations of prostanoid products. At 1 h after intravenous interferon-alpha administration (18 x 10(6) I.U.), pulmonary arterial pressure and pulmonary vascular resistance were significantly increased compared to the baseline values. The levels of thromboxane B2 in both plasma and lung lymph were increased concomitant with early elevation on pulmonary arterial pressure. In addition, OKY-046 [sodium-3[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid] (10 mg kg(-1)), a selective thromboxane synthase inhibitor, significantly prevented the interferon-alpha-induced pulmonary hypertension and thromboxane B2 production. While no evidence of increased pulmonary vascular leakage was observed. These findings suggest that a single infusion of interferon-alpha stimulates a thromboxane cascade and causes transient pulmonary hypertension. However, interferon-alpha itself or increased thromboxane A2 might not affect the pulmonary vascular permeability in sheep.

Ultrastructural studies on the formation and distribution of lipid droplets in the lung capillary endothelial cells in patients with sarcoidosis

BACKGROUND AND AIM OF THE WORK

We previously reported the presence of definite morphological alterations in the capillary endothelium of sarcoid lung. The aim of this study was to examine ultrastructural changes and distribution of lipid droplets in the endothelium of lung capillaries of patients with sarcoidosis.

METHODS

Tissue specimens were obtained by transbronchial lung biopsy or open lung biopsy from 16 patients with sarcoidosis and 13 controls. Biopsies were evaluated by electron microscopy following lead citrate and uranyl acetate staining.

RESULTS

Typical lipid droplets were observed in pulmonary capillaries of 11 out of 16 sarcoid patients (69%); the droplet frequency was higher in sarcoid patients than in control specimens. Lipid droplets were characterized by biphasic density: most droplets contained eccentrically located vacuoles (saturated fatty acids) others were characterized by low density areas (unsaturated fatty acids). Biphasic droplets were covered by large lysosomal granules and were mainly distributed in the endothelium and pericytes. Interestingly, in the latter, vacuoles increased in size while small amounts of lysosomal granules were detectable.

CONCLUSION

Our findings suggest that biphasic droplets increase in number in pulmonary capillaries of patients with sarcoidosis with a characteristic distribution pattern from the endothelium to pericytes.

Effects of proline mutations on the folding of staphylococcal nuclease

Effects of proline isomerizations on the equilibrium unfolding and kinetic refolding of staphylococcal nuclease were studied by circular dichroism in the peptide region (225 nm) and fluorescence spectra of a tryptophan residue. For this purpose, four single mutants (P11A, P31A, P42A, and P56A) and four multiple mutants (P11A/P47T/P117G, P11A/P31A/P47T/P117G, P11A/P31A/P42A/P47T/P117G, and P11A/P31A/P42A/P47T/P56A/P117G) were constructed. These mutants, together with the single and double mutants for Pro47 and Pro117 constructed in our previous study, cover all six proline sites of the nuclease. The P11A, P31A, and P42A mutations did not change the stability of the protein remarkably, while the P56A mutation increased protein stability to a small extent by 0.5 kcal/mol. The refolding kinetics of the protein were, however, affected remarkably by three of the mutations, namely, P11A, P31A, and P56A. Most notably, the amplitude of the slow phase of the triphasic refolding kinetics of the nuclease observed by stopped-flow circular dichroism decreased by increasing the number of the proline mutations; the slow phase disappeared completely in the proline-free mutant (P11A/P31A/P42A/P47T/P56A/P117G). The kinetic refolding reactions of the wild-type protein assessed in the presence of Escherichia coli cyclophilin A showed that the slow phase was accelerated by cyclophilin, indicating that the slow phase was rate-limited by cis-trans isomerization of the proline residues. Although the fast and middle phases of the refolding kinetics were not affected by cyclophilin, the amplitude of the middle phase decreased when the number of the proline mutations increased; the percent amplitudes for the wild-type protein and the proline-free mutants were 43 and 13%, respectively. In addition to these three phases detected with stopped-flow circular dichroism, a very fast phase of refolding was observed with stopped-flow fluorescence, which had a shorter dead time (3.6 ms) than the stopped-flow circular dichroism. The following conclusions were drawn. (1) The effects of the P11A, P31A, and P56A mutations on the refolding kinetics indicate that the isomerizations of the three proline residues are rate-limiting, suggesting that the structures around these residues (Pro11, Pro31, and Pro56) may be organized at an early stage of refolding. (2) The fast phase corresponds to the refolding of the native proline isomer, and the middle phase whose amplitude has decreased when the number of proline mutations was increased may correspond to the slow refolding of non-native proline isomers. The occurrence of the fast- and slow-refolding reactions together with the slow phase rate-limited by the proline isomerization suggests that there are parallel folding pathways for the native and non-native proline isomers. (3) The middle phase did not completely disappear in the proline-free mutant. This suggests that the slow-folding isomer is produced not only by the proline isomerizations but also by another conformational event that is not related to the prolines. (4) The very fast phase detected with the fluorescent measurements suggests that there is an intermediate at a very early stage of kinetic refolding.

Paradoxical effects of pirenzepine on parasympathetic activity in chronic heart failure and control

We studied the effect of intravenous pirenzepine (3 mg) in normal subjects (n=15, 43+/-16 years old) and in patients with chronic heart failure (n=15, 61+/-12 years old) to assess the effect of low-dose pirenzepine on vagal activity. R-R intervals and the standard deviations, low-frequency power (LF: ln ms2, 0.04-0.15 Hz), high-frequency power (HF: ln ms2, 0.15-0.40 Hz) and the ratio of low- to high-frequency power (LF/HF ratio) were measured 10 min before and after pirenzepine using a Holter analysis system. Pirenzepine was found to cause a significant increase in the R-R interval from 903+/-112 to 956+/-129 ms in the control group (P<0.0001) and from 927+/-141 to 958+/-168 ms in patients with chronic heart failure (P<0.01). Pirenzepine also increased HF significantly from 4.29+/-0.32 to 5.16+/-0.38 ln ms2 in the control group (P<0.0001) and from 4.04+/-0.16 to 4.48+/-0.24 ln ms2 in the chronic heart failure group (P<0.05). Pirenzepine did not significantly alter the LF/HF ratio in either group. We emphasize that pirenzepine appears to have a vagoinimetic effect in patients with chronic heart failure and that it may be useful for augmenting vagal control of the heart in some patients with chronic heart failure.

Molecular evolution of the domain structures of protein disulfide isomerases

Protein disulfide isomerase (PDI) is an enzyme that promotes protein folding by catalyzing disulfide bridge isomerization. PDI and its relatives form a diverse protein family whose members are characterized by thioredoxin-like (TX) domains in the primary structures. The family was classified into four classes by the number and the relative positions of the TX domains. To investigate the evolution of the domain structures, we aligned the amino acid sequences of the TX domains, and the molecular phylogeny was examined by the NJ and ML methods. We found that all of the current members of the PDI family have evolved from an ancestral enzyme, which has two TX domains in the primary structure. The diverse domain structures of the members have been generated through domain duplications and deletions.

Pharmacokinetic evaluation of amphotericin B in lung tissue: lung lymph distribution after intravenous injection and airspace distribution after aerosolization and inhalation of amphotericin B

We have studied the pharmacokinetics of amphotericin B (AmB) in lung lymph circulation and bronchial-wash fluid after intravenous infusion and inhalation, respectively. For two experiments with awake sheep, we used lung lymph fistulas and tracheotomy. In experiment 1, AmB concentrations in plasma and lung lymph after intravenous infusion of AmB (1 mg/kg of body weight) over 1.5 h were measured. The mean peak in plasma level was 756.0 +/- 188.8 ng/ml at 3 h after the start of infusion, and the level then decreased gradually to 194.8 +/- 28.9 ng/ml at 24 h. The stable and maximal levels in lung lymph last 5 to 9 h after the start of AmB infusion. The concentrations in lung lymph after 9 h were slightly higher than those in plasma. Thus, the lung lymph-to-plasma ratio of AmB concentrations increased gradually during infusion, and the ratio was more than 1.0 after the end of infusion, suggesting that AmB could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. In another experiment, 5 or 30 mg of aerosol AmB was inhaled, and the concentration of AmB in the bronchial-wash fluid was determined by bronchoalveolar lavage. The peak AmB concentration in the fluid was observed at 0.5 h. After that, AmB was slowly eliminated over 24 h. The area under the concentration-time curve for 30 mg of inhaled AmB was higher than that for 5 mg, but maximum concentrations of AmB in serum for 5 and 30 mg were almost similar. These observations identify the pharmacokinetic characteristics of AmB in the lung and may provide a new insight into the strategy for clinical treatment of fungal pneumonia.

[Radiofrequency catheter ablation therapy in elderly patients with supraventricular tachycardia]

138 patients with Wolf-Parkinson-White (WPW) syndrome (n = 96), atrioventricular nodal reentrant tachycardia (AVNRT; n = 27) and the other supraventricular tachycardia (n = 15), were divided into two groups, a control group (less than 65 years old; n = 108) and an elderly group (more than 66 years old; n = 30). We then estimated the success rate and safety of radiofrequency ablation for supraventricular tachycardia in elderly patients. For WPW syndrome, there were 76 (97%) successes and 9 (13%) recurrences in the control group (n = 78). In the elderly group of WPW patients, the number of successes was 18 (100%) and the number of recurrences one (63%). In 27 patients with AVNRT, the number of successes was 26 (96%) and there were no recurrences. In 15 patients with some other supraventricular tachycardia, there were 11 patients (73%) successes and one recurrence (11%). Major complications consisted of cardiac tamponade in 2 patients, dissecting aneurysm in one patient and cerebral embolism in one patients. All major complications occurred in patients with WPW syndrome. The cause of the complications, except the cerebral embolism was manipulation of the electrical or ablation catheter. Three of four patients with major complications belonged to the control group. It is possible that radiofrequency catheter ablation for supraventricular tachycardia in elderly patients is safe and highly effective. However, it is still invasive therapy. Ablation on a left accessory pathway by the transaortic valve approach especially needs meticulous care.

Inflammatory cytokines in BAL fluid and pulmonary hemodynamics in high-altitude pulmonary edema

To evaluate the pathogenesis of high-altitude pulmonary edema (HAPE), we performed bronchoalveolar lavage (BAL) and pulmonary hemodynamic studies in seven patients with HAPE at its early stage. We measured cell counts, biochemical contents, and concentrations of pro-inflammatory cytokines including interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha and of anti-inflammatory cytokines including IL-1 receptor antagonist (ra) and IL-10 in the BAL fluid (BALF). All patients showed increased counts for total cells, alveolar macrophages, neutrophils and lymphocytes, and markedly elevated concentrations of proteins, lactate dehydrogenase, IL-1beta, IL-6, IL-8, TNF-alpha and IL-1ra. The levels of IL-1alpha and IL-10 were not increased. Patients also showed pulmonary hypertension with normal wedge pressure. Both the driving pressure obtained as pulmonary arterial pressure minus wedge pressure and the PaO2 under room air were significantly correlated with the concentrations of IL-6 and TNF-alpha in the BALF. These findings suggest that the inflammatory cytokines play a role at the early stage of HAPE and might be related to pulmonary hypertension.

Isolation of anti-glutathione antibodies from a phage display library

We have isolated anti-glutathione antibodies from a human synthetic phage antibody scFv library (Nissim,A., Hoogenboom,H.R., Tomlinson,I.M., Flynn,G., Midgley,C., Lane,D. and Winter,G., 1994, EMBO J., 13, 692-698). Glutathione (GSH) conjugates with carrier proteins, such as bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH) and human lysozyme (LZM), were used as antigens. After four cycles of panning and affinity chromatography, clones that recognized GSH-conjugated proteins, but not BSA, KLH or LZM, were isolated. The isolated phage antibodies and the soluble scFv fragments were characterized by immunoblotting, and the nucleotide sequences of the VH segments of selected clones were determined. The binding of several isolates to GSH-BSA was competitively inhibited by GSH in an ELISA. These observations have demonstrated that antibodies against GSH, a tripeptide, can be isolated from the library. We constructed the tertiary models of several scFv fragments and discussed the mechanism of antigen binding sites.

Churg-Strauss syndrome (allergic granulomatous angitis) presenting with ileus caused by ischemic ileal ulcer

We report a rare case of Churg-Strauss syndrome (CSS) in a 41-year-old Japanese man with a history of middle-age onset of bronchial asthma who had severe abdominal pain. He presented with ileus caused by an annular ulcer of the ileum, attributable to mucosal ischemia resulting from necrotizing vasculitis of the mesenteric artery. He also had marked hypereosinophilia (51.5%), elevated serum IgE levels (34040 IU/ml), and generalized enlargement of the superficial cervical lymph nodes, containing eosinophilic granulomas. A stenotic lesion caused by an annular ulcer in the ileum was found and resected by laparotomy. Microscopic examination of the resected specimen revealed luminal narrowing or occlusion of small arteries in the ulcer base, subserosa, and mesenterium resulting from marked fibrotic intimal thickening with fragmentation or lack of the internal elastic lamina. These findings were diagnosed as vasculitis, scar stage. The postoperative course was uneventful, with the patient receiving a maintenance dose of prednisolone (10-15 mg/day) for 7 years subsequently. We must carefully diagnose and treat patients with middle-age onset asthma, because the symptom may be a lung manifestation of CSS, in which various organs including gastrointestinal tract are involved as a result of systemic necrotizing vasculitis.

Effect of post-treatment with granulocyte colony-stimulating factor on endotoxin-induced lung injury in sheep

We administered a bolus of G-CSF (250 micrograms/body) just after the infusion of endotoxin (1 microgram/kg) in awake sheep with chronic lung lymph fistula to examine the effect of post-treatment with G-CSF on endotoxin-induced lung injury. We measured pulmonary hemodynamics, lung lymph flow, and concentrations of thromboxane B2 and 6-keto-prostaglandin F1 alpha in plasma and lung lymph. In the G-CSF post-treated group, the pulmonary arterial pressure, pulmonary vascular resistance, and lung lymph flow did not significantly increase in the late period (3-5 h after endotoxin infusion). The arterial oxygen gas tension in the late period was higher in the G-CSF post-treated sheep than in those that received only endotoxin. Although the level of thromboxane B2 in plasma significantly increased at 1 h after endotoxin, the lung lymph flow did not increase much in the G-CSF post-treated group. We conclude that post-treatment with G-CSF instead attenuates the degree of pulmonary vascular leakage on endotoxin-induced lung injury and increased thromboxane B2, the principle metabolite of thromboxane A2, may not exacerbate the injury in awake sheep.

Neutrophils pretreated with granulocyte colony-stimulating factor (G-CSF) are not related to the severity of endotoxin-induced lung injury

Neutrophils play an important role in mediating acute lung injury that is characteristic of adult respiratory distress syndrome. Granulocyte colony-stimulating factor (G-CSF) has been shown to increase neutrophil counts and to enhance their biological functions. This study investigated the effects of neutrophils pretreated with G-CSF on endotoxin-induced lung injury in conscious sheep. Nineteen sheep were chronically instrumented with a lung lymph fistula and vascular catheters for monitoring. Sheep were randomly allocated into three groups: group 1-sheep were infused only with endotoxin; group 2-G-CSF (250 micrograms/day) was administered intravenously for 5 days prior to endotoxin; and group 3-G-CSF (125 micrograms) was administered just before endotoxin. In each group, sheep received E. coli endotoxin (1 microgram/kg) for 30 min and observations were made for 5 h after endotoxin administration. Circulating leukocyte counts before endotoxin markedly increased in group 2 and significantly decreased in group 3, when compared with the level in group 1 (9700 +/- 900 (SEM) in group 1, 49,900 +/- 10,000 in group 2, and 3600 +/- 600/microL in group 3). In each group, circulating leukocyte counts significantly decreased 1 h after endotoxin administration and then returned to baseline values. However, there were no significant differences in either pulmonary hemodynamic or lung lymph responses to endotoxin among the groups. The results indicate that G-CSF does not adversely affect physiologic responses of the lung to endotoxin in sheep.

Stabilized analogs of thymopentin. 1. 4,5-Ketomethylene pseudopeptides

The pentapeptide, thymopentin (Arg1-Lys2-Asp3-Val4-Tyr5) is known for its activity as an immunomodulating drug, but with limited half-life in plasma. In this first paper of a series of three studies, the synthesis of analogs stabilized at the peptide bond between the C-terminal amino acids via insertion of a ketomethylene moiety is described. N-Blocked pseudopeptides containing Val(k)Phe, Ala(k)Phe, and Val(k)Val units were prepared and attached to chloromethyl Merrifield resin via the carboxy terminal. Removal of the N-BOC group by trifluoroacetic acid was followed by sequential coupling with N-BOC dipeptides of aspartic acid to yield resin-bound N-BOC pseudotetrapeptides. Removal of N-BOC and coupling with N-BOC-r-N-tosylarginine followed by total cleavage of blocking groups and resin by HF afforded the target pseudopentapeptides. The analogs were found to compete favorably with thymopentin for binding to CEM cells, but binding was reduced by about 20-30% on average. All analogs showed significant enhancement of half-life versus thymopentin in mouse serum, but most showed only modest improvement in human serum. Insertion of proline or norleucine at position 2 in the chain caused a substantial increase in half-life (3-4-fold), while N-methylnorleucine conferred complete stability in the analogs.

[Tumor lysis syndrome after treatment for mediastinal non-Hodgkin's lymphoma]

An 18-year man was admitted to the hospital because of acute dyspnea. Roentgenological examination revealed a large anterior mediastinal tumor. Histologic examination of a specimen from a cervical lymph node yielded a diagnosis of non-Hodgkin's lymphoma of, diffuse, large, T-cell type. Acute respiratory failure and a massive pleural effusion developed, and mechanical ventilation was begun. Chemotherapy with adriamycin, vincristine, cyclophosphamide, and prednisolone resulted in rapid shrinking of the mass. Acute renal failure developed because of hypoperfusion of the kidney caused by acute circulatory failure and the tumor lysis syndrome, and rapid increases in the concentrations of lactate dehydrogenase, creatine phosphokinase, and uric acid in serum after the tumor collapsed. Mediastinal malignant lymphoma often forms a bulky mass, and effective chemotherapy, while it can prolong survival, may also cause the tumor lysis syndrome.

[Two patients with idiopathic pulmonary fibrosis and monoclonal gammopathy]

A 67-year-old man and a 70-year-old man were admitted to our hospital because of dyspnea and dry coughing. Chest X-ray films showed bilateral reticulonodular shadows in the middle and lower lung fields. Specimens were obtained by open lung biopsies and the findings were compatible with those of usual interstitial pneumonia. Immunoelectrophoresis revealed monoclonal gammopathy in both patients. The levels of interleukin 6 in bronchoalveolar lavage fluid were high. In these two patients, idiopathic pulmonary fibrosis was associated with multiple myeloma and monoclonal gammopathy, and the levels of interleukin-6 in bronchoalveolar lavage fluid were high. These findings may help to elucidate the pathogenesis and development of idiopathic pulmonary fibrosis.