The phosphodiesterase 4 inhibitor AA6216 suppresses activity of fibrosis-specific macrophages

BackgroundIdiopathic pulmonary fibrosis (IPF) is a form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, with a poor prognosis. We previously showed the antifibrotic effects of a novel phosphodiesterase 4 (PDE4) inhibitor, AA6216. In this study, we examined the effect of AA6216 on the pulmonary accumulation of segregated-nucleus-containing atypical monocytes (SatMs), which produce tumor necrosis factor (TNF)-α and are involved in murine lung fibrosis.MethodsMice were treated with bleomycin intratracheally at day 0 and either 10 mg/kg AA6216, 100 mg/kg nintedanib, or vehicle orally once daily from day 0 to 8. On day 9, we isolated the bronchoalveolar lavage fluid and analyzed the SatM ratio. In addition, we evaluated the effect of AA6216 on TNF-α production from SatMs isolated from murine bone marrow.ResultsAA6216, and not the antifibrotic agent nintedanib, significantly suppressed the pulmonary accumulation of SatMs (AA6216: 68.3 ± 5.4%, Nintedanib: 129.8 ± 19.7%). Furthermore, AA6216 dose-dependently inhibited the production of TNF-α by SatMs.ConclusionsAA6216 suppresses pathogenic SatMs in the lung, which contributes to its antifibrotic effects.     

Structural Analysis of a recA-like Gene in the Genome of Arabidopsis thaliana

A recA-like gene was identified in the genome of Arabidopsisthaliana by means of PCR using primers designed on the basisof previously reported amino acid sequences of eukaryotic RecA-likeproteins. The structure of the gene, termed ArLIM15, was investigatedby comparing the primary structure of the genomic DNA with thatof the corresponding cDNA. The open reading frame, which wassplit into 15 exons, was established to have the capacity forencoding a 37.3-kDa polypeptide. The amino acid sequence ofthe putative product of ArLIM15 showed a high degree of similaritytothat of LIM15 in the monocotyledonous plant Lilium, includinga 93% identity, and to those of other recA-like genes in yeastsand vertebrates with identities of 69–71%. Phylogeneticanalysis indicated ArLIM15 to be much closer to meiosis-specificLIM15 and DMC1 in Saccharomyces cerevisiae than to RAD51 inS. cerevisiae and its homologues on an evolutionary scale.     

Complete Genome Structure of the Unicellular Cyanobacterium Synechocystis sp. PCC6803

Cyanobacteria are photoautotrophic organisms capable of oxygen-producingphotosynthesis similar to that in eukaryotic algae and plants,and because of this, they have been used as model organismsfor the study of the mechanism and regulation of oxygen-producingphotosynthesis. To understand the entire genetic system in cyanobacteria,the nucleotide sequence of the entire genome of the unicellularcyanobacterium Synechocystis sp. PCC6803 has been determined.The total length of the circular genome is 3,573,470 bp, witha GC content of 47.7%. A total of 3,168 potential protein codinggenes were assigned. Of these, 145 (4.6%) were identical toreported genes, and 1,259 (39.6%) and 342 (10.8%) showed similarityto reported and hypothetical genes, respectively. The remaining1,422 (45.0%) showed no apparent similarity to any genes registeredin the databases. Classification of the genes by their biologicalfunction and comparison of the gene complement with those ofother organisms have revealed a variety of features of the geneticinformation characteristic of a photoautotrophic organism. Thesequence data, as well as other information on the Synechocystisgenome, is presented in CyanoBase on WWW [http://www.kazusa.or.jp/cyano/]. (Received July 24, 1997; Accepted September 17, 1997)     

Effect of carbon dioxide and ethylene on berberine production and cell browning in Thalictrum minus cell cultures

Cultured cells of Thalictrum minus L. (Ranunculaceae), transferred from culture flasks to a bubble column bioreactor, produced little berberine and turned dark brown, even when supplied with sufficient oxygen. This phenomenon was ascribed to the removal of CO₂ from the culture medium by bubbling air, and could be reproduced in flask cultures artificially deprived of CO₂. The induction of cell browning by exogenously administered ethylene suggested that CO₂ probably acts antagonistically against endogenously generated C₂H₄. The physiological damage caused by forced aeration could be prevented by adding 2 % CO₂ to the air in the bioreactor.     

An Analysis of Osterhout and Hill's Salt Bridge Experiments in Characeae Internode

Conduction of action potentials in Chara internodal cells wasblocked at a 5%-urethane treated region. The action potentialscould be propagated beyond this region when an electric bridgewas built across it with a low enough resistance that the actioncurrent across it could depolarize the membrane at the distaljunction of the bridge up to the threshold level. After recoveryof propagation, the configuration of the action current flowingthrough the bridge changed from monophasic to diphasic. Coursesof the monophasic action current and the depolarizing potentialof the resting membrane were in parallel with the course ofaction potential, although they were slightly out of phase witheach other. The magnitudes of the current and depolarizing potentialagreed well with those estimated using a simplified equivalentcircuit of the bridge arrangement or with those observed usingan electric model circuit. ¹Present address: Department of Physiology, Tohoku UniversitySchool of Dentistry, Seiryo-machi, Sendai 980, Japan. ²Present address: Biology Laboratory, Kyoritsu Women's University,Hachioji, Tokyo 193, Japan. (Received December 18, 1985; Accepted March 26, 1986)     

Glucosylation of esculetin by plant cell suspension cultures

Cell suspension cultures of Lithospermum erythrorhizon, Gardenia jasminoides and Nicotiana tabacum were capable of glucosylating esculetin to esculin (7-hydroxycoumarin-6-O-β-D-glucoside). Especially, a culture strain of Lithospermum erythrorhizon was superior in the esculetin glucosylating capability; 40 to 50% of esculetin administered to the culture medium at early stationary growth stage was converted into esculin within 24 h. The rate of glucosylation was also dependent on the growth stage and the medium composition especially growth hormones and sugar.     

Plant saponins can affect DNA recombination in cultured mammalian cells

Some plant extracts and products are known to affect mammalian cells, tissues and organisms as they contain a toxic substance or a metabolic stimulant. Our biochemical investigations revealed that some plant saponins can increase the cellular DNA repair activity and the general recombinase activity measured by in vitro assay (1). In the experiments described here, HeLa cells were cultured for several days with plant saponins or flavonoids and analyzed to measure i) recombination activity of the cell extract by induction of Tcr colonies from two mutant DNAs (mutants 1 and 2, which are both tetracycline sensitive) after transformation into E. coli recA-, and ii) repair synthesis of nuclear DNA followed by incorporation of 3H-thymidine. Saikosaponins a, b1, d, ginsenosides Rb1, Re, Rh and flavonoid baicalin caused a significant stimulation of intermolecular recombination. It is worth noting that none of the plant saponins and flavonoids had any inhibitory or toxic effect at concentrations less than 25 micrograms/ml in the culture media.