Action-at-a-distance mutagenesis induced by oxidized guanine in Werner syndrome protein-reduced human cells.

8-Oxo-7,8-dihydroguanine (G(O), 8-hydroxyguanine) in DNA is one of the most important oxidatively damaged bases and causes G:C → T:A substitution mutations. The Werner syndrome protein (WRN) is a cancer-related RecQ DNA helicase and plays many roles in DNA replication and repair. To examine the relationships between G(O)-induced mutations and WRN, shuttle plasmid DNA containing a G(O):C pair in the supF gene was transfected into human U2OS cells, in which WRN was knocked down. The plasmid DNA replicated in the knockdown cells was introduced into an Escherichia coli indicator strain. The knockdown of WRN increased the mutant frequency of the G(O)-plasmid DNA. Unexpectedly, however, the WRN knockdown only slightly enhanced the targeted G:C → T:A mutation. Instead, base-substitution mutations at various positions were more frequently detected, with statistical significance. The results obtained in this study suggested that the reduction of the cancer-related WRN induced action-at-a-distance mutagenesis by the G(O):C pair in human cells. In addition, the WRN knockdown decreased the G(O):A-induced A:T → C:G mutations, suggesting that WRN may enhance the mutations caused by G(O) in the nucleotide pool.

A case of emphysematous pyelonephritis in an older man with poorly controlled type 2 diabetes mellitus.

Emphysematous pyelonephritis (EPN) is a necrotizing bacterial infection characterized by gas retention and a poor prognosis. We present the case of a 75-year-old man who was diagnosed early with EPN and received multidisciplinary treatment. He had poorly controlled type 2 diabetes mellitus (DM) and chronic kidney disease (CKD), and was treated with oral hypoglycemic drugs, including a sodium-glucose co-transporter-2 inhibitor. He experienced the onset of back pain in the midsection of his back, tenderness in the costovertebral angle, and a high fever (> 39 °C), accompanied by tachycardia, hypotension, and tachypnea. The patient was diagnosed with pyelonephritis and septic shock. Immediate measures encompassing empirical antibiotic therapy, administration of noradrenaline, blood glucose regulation, and urethral catheterization were implemented. However, due to the persistent fever (> 38 °C) and lack of improvement in his condition, abdominal computed tomography (CT) was repeated on the fourth day. This revealed the presence of gas around the right kidney parenchyma, leading to a diagnosis of EPN that had evolved from acute pyelonephritis. Subsequently, percutaneous drainage of the right kidney parenchyma was performed. Subsequently, multidisciplinary treatment was continued, and his condition gradually improved. Clinicians should evaluate abdominal CT when acute pyelonephritis does not improve within a few days of antibiotic therapy. Disease progression from acute pyelonephritis to EPN should be considered in patients with DM and CKD.

Protein Concentration of Refractory Ascites in Cancer Patients is Reflected by the Presence and Severity of Peritoneal and Liver Metastasis.

Ascites total protein concentration (A-TP) affects the performance of cell-free and concentrated ascites reinfusion therapy (CART). As the factors determining A-TP remain unclear, we examined peritoneal and liver metastasis. Among 98 patients who received CART, 68 with cancer, ascites from no other apparent cause, and complete CT and A-TP data were recruited. Sixty-six patients (97%) with peritoneal and/or liver metastasis on CT were divided into the peritoneal metastasis group (PM group), peritoneal and liver metastasis group (PM + LM group), and liver metastasis group (LM group). A-TP was highest in the PM group (3.9 g/dL [3.4-4.4]), lowest in the LM group (1.0 g/dL [0.9-2.0]), and broadly dispersed in the PM + LM group (3.3 g/dL [2.0-3.8]). All differences were statistically significant. The percentage of metastasis volume occupying the liver was negatively and significantly related to A-TP in the PM + LM group. Taken together, the presence and severity of peritoneal and liver metastasis may influence A-TP.

The nanoparticulation by octaarginine-modified liposome improves α-galactosylceramide-mediated antitumor therapy via systemic administration.

Alpha-galactosylceramide (αGC), a lipid antigen present on CD1d molecules, is predicted to have clinical applications as a new class of adjuvant, because αGC strongly activates natural killer T (NKT) cells which produce large amounts of IFN-γ. Here, we incorporated αGC into stearylated octaarginine-modified liposomes (R8-Lip), our original delivery system developed for vaccines, and investigated the effect of nanoparticulation. Unexpectedly, the systemic administered R8-Lip incorporating αGC (αGC/R8-Lip) failed to improve the immune responses mediated by αGC compared with soluble αGC in vivo, although αGC/R8-Lip drastically enhanced αGC presentation on CD1d in antigen presenting cells in vitro. Thus, we optimized the αGC/R8-Lip in vivo to overcome this inverse correlation. In optimization in vivo, we found that size control of liposome and R8-modification were critical for enhancing the production of IFN-γ. The optimization led to the accumulation of αGC/R8-Lip in the spleen and a positive therapeutic effect against highly malignant B16 melanoma cells. The optimized αGC/R8-Lip also enhanced αGC presentation on CD1d in antigen presenting cells and resulted in an expansion in the population of NKT cells. Herein, we show that R8-Lip is a potent delivery system, and size control and R8-modification in liposomal construction are promising techniques for achieving systemic αGC therapy.

Visualization of abscisic acid-perception sites on the plasma membrane of stomatal guard cells.

Abscisic acid (ABA) is a phytohormone that plays a key role as a stress signal, regulating water relations during drought conditions, by inducing stomatal closure. However, to date, no putative ABA receptor(s) has been reported at the protein sequence, gene family, or cellular localization levels. We used biotinylated ABA (bioABA) to characterize the ABA-perception sites in the stomatal guard cells of Vicia faba. Treatment with bioABA induced stomatal closure and shrinkage of guard cell protoplasts (GCPs). The ABA-perception sites were visualized by fluorescence microscopy and confocal laser scanning microscopy (CLSM), using bioABA and fluorescence-labeled avidin. Fluorescent particles were observed in patches on the surface of the GCPs. Fluorescence intensity was quantified by flow cytometry (FCM) as well as by CLSM. Binding of bioABA was inhibited by ABA in a dose-dependent manner. Pre-treatment of GCPs with proteinase K also blocked the binding of bioABA. Binding of bioABA was inhibited by RCA-7a, an ABA analog that induces stomatal closure, but not by RCA-16, which has no effect on stomatal aperture. Another ABA analog, PBI-51, inhibited ABA-induced stomatal closure. This ABA antagonist also inhibited binding of bioABA to the GCPs. These results suggest that ABA is perceived on the plasma membrane of stomatal guard cells, and that the present experimental methods constitute valuable tools for characterizing the nature of the ABA receptor(s) that perceives physiological ABA signals. These imaging studies allow us to demonstrate the spatial distribution of the ABA-perception sites. Visualization of the ABA-perception sites provides new insights into the nature of membrane-associated ABA receptor(s).