Changes in the distribution of the substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the laryngeal mucosa of chronically hypoxic rats.

The distribution and abundance of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive nerve fibers in four different regions of the laryngeal mucosa were compared between normoxic and chronically hypoxic rats (10% O2 and 3.0-4.0% CO2 for 3 months). In the chronically hypoxic laryngeal mucosa, the number of SP and CGRP fibers within and just beneath the epithelium, and around the laryngeal gland was increased in comparison with those in the normoxic controls. Especially in the epiglottic and arytenoid regions, the number of intraepithelial SP fibers was increased remarkably. Most intraepithelial SP and CGRP fibers penetrated into the epithelium to extend to the luminal surface. There was no distinct difference in the distribution and abundance of these peptidergic fibers in the mucosa of the normoxic and chronically hypoxic vocal cord regions. These results suggest that the increased density of SP and CGRP fibers within the epithelium of the upper laryngeal mucosa is a predominant feature of hypoxic adaptation, and this may be involved in airway protection, swallowing, and other functions in the chronically hypoxic environment. In addition, the increased SP and CGRP fibers around the laryngeal gland suggest an enhanced mucous secretion, and this may participate in the airway defense mechanism in low O2 conditions.     

Exploration of the binding proteins of perfluorooctane sulfonate by a T7 phage display screen

Perfluorooctane sulfonate (PFOS) is a pollutant widely found throughout nature and is toxic to animals. We created a PFOS analogue on a polyethylene glycol polyacrylamide copolymer and isolated peptides that preferentially bound the PFOS analogue using a T7 phage display system. Bioinformatic analysis using the FASTAskan program on the RELIC bioinformatics server showed several human proteins that likely bound PFOS. Among them, we confirmed binding between PFOS and a recombinant soluble form of monocyte differentiation antigen CD14 (sCD14) by a surface plasmon biosensor. Furthermore, PFOS inhibited TNF-α production induced by the sCD14 in mouse macrophage RAW264.7 cells.     

Effect of ipriflavone on glucocorticoid-induced osteoporosis in rats

Ipriflavone, 7-isopropoxy-3-phenyl-4H-1-benzopyran-4-one, was administered orally for 12 weeks to male rats with prednisolone-induced osteoporosis. Microdensitometric analysis of a roentgenograph of the femurs revealed that ipriflavone increased the density of the distal metaphysis dose-dependently and tended to increase the density of the diaphysis. It also inhibited dose-dependently the decrease in the mechanical strength of the tibia, breaking strain and breaking energy, and the fractional content of ash in femurs. These results indicate that ipriflavone markedly suppresses bone resorption at the metaphysis where the content of trabecular bone with a rapid turnover rate is high, and possibly inhibits bone reduction at the diaphysis.     

Human B lymphocytes activated by Epstein-Barr virus (EBV) or by mitogens suppress mitogen-induced immunoglobulin production

Polyclonal activation of human B lymphocytes by LPS or protein A, alone or in combination or by Epstein-Barr virus (EBV), generates suppressive conditions that inhibit the response of human B lymphocytes to pokeweed mitogen (PWM), measured by the induction of immunoglobulin-secreting cells (PFC). Moreover, EBV-transformed B cell lines of normal or neoplastic (Burkitt lymphoma) origin also suppressed the PWM-induced immunoglobulin production of normal B cells. Cell separation experiments have shown that mitogen activated autologous B cells stimulate suppressor T cells in a similar way as B cell-derived lymphoblastoid cell lines. The significance of this phenomenon is considered in relation to the escape of the activating microorganism or virus from immune control and the occurrence of network interactions within the immune system.     

The antitumor agent doxorubicin binds to Fanconi anemia group F protein

Doxorubicin, a commonly used cancer chemotherapy agent, elicits several potent biological effects, including synergistic-antitumor activity in combination with cisplatin. However, the mechanism of this synergism remains obscure. Here, we employed an improved T7 phage display screening method to identify Fanconi anemia group F protein (FANCF) as a doxorubicin-binding protein. The FANCF-doxorubicin interaction was confirmed by pull-down assay and SPR analysis. FANCF is a component of the Fanconi anemia complex, which monoubiquitinates D2 protein of Fanconi anemia group as a cellular response against DNA cross-linkers such as cisplatin. We observed that the monoubiquitination was inhibited by doxorubicin treatment.     

INO80-dependent chromatin remodeling regulates early and late stages of mitotic homologous recombination

Chromatin remodeling is emerging as a critical regulator of DNA repair factor access to DNA damage, and optimum accessibility of these factors is a major determinant of DNA repair outcome. Hence, chromatin remodeling is likely to play a key role in genome stabilization and tumor suppression. We previously showed that nucleosome eviction near double-strand breaks (DSBs) in yeast is regulated by the INO80 nucleosome remodeling complex and is defective in mutants lacking the Arp8 subunit of INO80. In the absence of homologous donor sequences, RPA recruitment to a DSB appeared normal in arp8Δ, but Rad51 recruitment was defective. We now show that the early strand invasion step of homologous recombination (HR) is markedly delayed in an arp8Δ haploid, but there is only a minor defect in haploid HR efficiency (MAT switching). In an arp8Δ diploid, interhomolog DSB repair by HR shows a modest defect that is partially suppressed by overexpression of Rad51 or its mediator, Rad52. In wild type cells, DSB repair typically results in gene conversion, and most gene conversion tracts are continuous, reflecting efficient mismatch repair of heteroduplex DNA. In contrast, arp8Δ gene conversion tracts are longer and frequently discontinuous, indicating defects in late stages of HR. Interestingly, when a homologous donor sequence is present, Rad51 is recruited normally to a DSB in arp8Δ, but its transfer to the donor is delayed, and this correlates with defective displacement of donor nucleosomes. We propose that retained nucleosomes at donors destabilize heteroduplex DNA or impair mismatch recognition, reflected in delayed strand invasion and altered conversion tracts.     

Preparation, crystal structures and spectroscopic properties of novel [MCl3 − n(P)3 + n] (M = Co, Rh; n = 0, 1, 2 or 3) series of complexes containing tripodal tridentate phosphine, 1,1,1-tris(dimethylphosphinomethyl)ethane

Cobalt(III) and rhodium(III) complexes of the series of [M^IIICl_3 − n(P)_3 + n]ⁿ⁺ (M = Co or Rh; n = 0, 1, 2 or 3) have been prepared with the use of 1,1,1-tris(dimethylphosphinomethyl)ethane (tdmme) and mono- or didentate phosphines. The single-crystal X-ray analyses of both series of complexes revealed that the M-P and M-Cl bond lengths were dependent primarily on the strong trans influence of the phosphines, and secondarily on the steric congestion around the metal center resulting from the coordination of several phosphine groups. In fact, the M-P(tdmme) bonds became longer in the order of [MCl₃(tdmme)] < [MCl₂(tdmme)(PMe₃)]⁺ < [MCl(tdmme)(dmpe)]²⁺ (dmpe = 1,2-bis(dimethylphosphino)ethane) < [M(tdmme)₂]³⁺ for both Co^III and Rh^III series of complexes, while the M-Cl bond lengths were shortened in this order (except for [M(tdmme)₂]³⁺). Such a steric congestion around the metal center can also account for the structural and spectroscopic characteristics of the series of complexes, [MCl(tdmme)(dmpm, dmpe or dmpp)]²⁺ (dmpm = bis(dimethylphosphino)methane, dmpp = 1,3-bis(dimethylphosphino)propane). The X-ray analysis for [CoCl(tdmme)(dmpm or dmpe)](BF₄)₂ showed that all Co-P bonds in the dmpm complex were shorter by 0.03-0.04 Å than those in the dmpe complex. Furthermore, the first d-d transition energy of the Co^III complexes and the ¹J_Rh-P(tdmme) coupling constants observed for the Rh^III complexes indicated an unusual order in the coordination bond strengths of the didentate diphosphines, i.e., dmpm > dmpe > dmpp.     

Discovery of novel tetracyclic compounds as anaplastic lymphoma kinase inhibitors

Anaplastic lymphoma kinase (ALK) receptor tyrosine kinase is considered a promising therapeutic target for human cancers. We identified novel tetracyclic derivatives as potent ALK inhibitors. Among them, compound 27 showed strong cytotoxicity against KARPAS-299 with an IC₅₀ value of 21 nM and significant antitumor efficacy in ALK fusion-positive blood and solid cancer xenograft models in mice without body weight loss.