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en: Characteristics of membrane transport, metabolism, and target protein binding of cyclic depsipeptide destruxin E in HeLa cells

en: Cyclic peptides have attracted attention as new modalities for drug development owing to their unique pharmacokinetic and pharmacodynamic properties. Destruxin E, a 19-membered cyclodepsipeptide, is a promising candidate drug for cancer therapy. The purpose of the present study was to clarify the molecular mechanisms underlying membrane transport, metabolism, and the binding for target molecules of destruxin E in human cervical carcinoma HeLa cells used as a model of cancer cells. The influx transport and the intracellular metabolism of destruxin E were non-saturable and saturable, respectively, at up to 10 μM. The intracellular amounts of destruxin E and destruxin E-diol after incubation of destruxin E with the cells significantly decreased at 4 °C compared to those at 37 °C. Destruxin E-diol, but not destruxin E, undergoes efflux transport out of cells via P-gp/MDR1/ABCB1 and BCRP/ABCG2. The epoxide hydrolase EPHX2 functions as a potent metabolizing enzyme that can convert the epoxide of destruxin E to the destruxin E-diol. Treatment with an EPHX2 inhibitor increased the intracellular destruxin E levels and enhanced the inhibitory activity of vacuolar type-H ATPase. These results suggest that epoxide hydrolase could be a regulatory factor for intracellular destruxin E levels and its pharmacological activity.

en: Drug Metabolism and Pharmacokinetics

ja: Drug Metabolism and Pharmacokinetics


en: Hypoxia suppresses glucose-induced increases in collective cell migration in vascular endothelial cell monolayers

en: Blood glucose levels fluctuate during daily life, and the oxygen concentration is low compared to the atmosphere. Vascular endothelial cells (ECs) maintain vascular homeostasis by sensing changes in glucose and oxygen concentrations, resulting in collective migration. However, the behaviors of ECs in response to high-glucose and hypoxic environments and the underlying mechanisms remain unclear. In this study, we investigated the collective migration of ECs simultaneously stimulated by changes in glucose and oxygen concentrations. Cell migration in EC monolayer formed inside the media channels of microfluidic devices was observed while varying the glucose and oxygen concentrations. The cell migration increased with increasing glucose concentration under normoxic condition but decreased under hypoxic condition, even in the presence of high glucose levels. In addition, inhibition of mitochondrial function reduced the cell migration regardless of glucose and oxygen concentrations. Thus, oxygen had a greater impact on cell migration than glucose, and aerobic energy production in mitochondria plays an important mechanistic role. These results provide new insights regarding vascular homeostasis relative to glucose and oxygen concentration changes.

en: Scientific Reports

ja: Scientific Reports


en: Transport characteristics of placenta-derived extracellular vesicles and its relevance to placenta-to-maternal tissues communication.

en: The placenta, a unique organ that helps maintain a healthy pregnancy, plays a pivotal role in maternal adaptation to pregnancy and releases extracellular vesicles (EVs), autacoids, and hormones. EVs are membranous vesicles released by all types of cells, including placental trophoblasts, which are involved in intracellular communication by delivering their cargo, such as proteins, nucleic acids, and lipids, to the targeted cells in a neighboring or distant location. Recently, an increasing number of publications have reported that EVs secreted from the placenta into maternal circulation deliver their cargo to maternal organs and mediate placenta-to-maternal communication during pregnancy. This review provides an overview of the transport mechanism of placenta-derived EVs to maternal organs.

en: Chemical & Pharmaceutical Bulletin

ja: Chemical & Pharmaceutical Bulletin


en: ATF4-mediated transcriptional regulation protects against β-cell loss during endoplasmic reticulum stress in a mouse model.

en: We conclude that transcriptional regulation by ATF4 maintains β-cell identity via ISR modulation. This mechanism provides a promising target for the treatment of diabetes.

ja: To examine the role of ATF4 in vivo, ISR enhancer Sephin1 (5 mg/kg body weight, p.o.) was administered daily for 21 days to Akita mice. We also established β-cell-specific Atf4 knockout (βAtf4-KO) mice that were further crossed with Akita mice. These mice were analyzed for characteristics of diabetes, β-cell function, and morphology of the islets. To identify the downstream factors of ATF4 in β-cells, the islets of βAtf4-KO mice were subjected to cDNA microarray analyses. To examine the transcriptional regulation by ATF4, we also performed in situ PCR analysis of pancreatic sections from mice and ChIP-qPCR analysis of CT215 β-cells.

en: Molecular Metabolism

ja: Molecular Metabolism