Biological & pharmaceutical bulletin最新文献

Proton pump inhibitors (PPIs), such as lansoprazole and omeprazole, are associated with an increased risk of cardiovascular events; however, the underlying mechanisms remain unclear. We investigated the inhibitory effects of lansoprazole and omeprazole on the formation of cardioprotective epoxyeicosatrienoic acids (EETs) and their downstream metabolites, dihydroxyeicosatrienoic acids (DHETs), from arachidonic acid catalyzed by CYP enzymes. In vitro incubation studies were conducted using human liver microsomes (HLMs), recombinant CYP2C19 (rCYP2C19), and recombinant CYP2C9 (rCYP2C9). IC₅₀ values and R values (a clinical drug-drug interaction risk predictor) were estimated. In HLMs, lansoprazole inhibited the formation of 5,6-, 8,9-, and 11,12-EETs. Omeprazole showed limited inhibition in comparison. In experiments using recombinant enzymes, lansoprazole and omeprazole strongly inhibited EET formation via rCYP2C19, but not rCYP2C9. Lansoprazole exhibited more potent inhibition than omeprazole. Notably, R values for lansoprazole in rCYP2C19 exceeded 1.1 for total EET and DHET formation. Molecular docking analysis suggested that both PPIs may bind to CYP2C19 in a similar pose to a known inhibitor. Docking scores also supported the stronger inhibitory potential of lansoprazole compared to omeprazole. In conclusion, lansoprazole and omeprazole suppress EET formation primarily via CYP2C19 inhibition. The predicted high risk (R > 1.1) for lansoprazole observed in the rCYP2C19 assay suggests a potential mechanism for the increased cardiovascular risk. Further clinical studies are warranted to validate these findings.

Mitochondria are essential organelles responsible for energy production, autophagy, and apoptosis, and mitochondrial dysfunction has been implicated in various diseases affecting the heart, liver, and kidneys. Mitochondrial transplantation, wherein isolated mitochondria are administered into cells or tissues, has recently emerged as a promising therapeutic approach for restoring cellular functions by enhancing ATP generation and reducing oxidative stress. However, the characteristics and functional diversity of the mitochondria isolated from different cell types remain poorly understood. Here, we aimed to identify the optimal mitochondrial source for transplantation therapy by comparing mitochondria isolated from several mammalian cell types, including mesenchymal stromal, hepatic, muscular, and pluripotent stem cells. Mitochondria were isolated using a streptolysin O-based isolation method and characterized through particle size, zeta potential, protein content, and ATP content. The isolated mitochondria exhibited uniform morphology, negative surface charge, sufficient protein yield, and ATP content, indicating successful preparation of functionally competent organelles suitable for comparative analysis. The mitochondria derived from mesenchymal stromal cells exhibited the highest bioenergetic activity. Adding these mitochondria enhanced cellular proliferation, oxygen consumption, and resistance to oxidative stress in recipient cells. Collectively, these findings demonstrate that mitochondria isolated from autologous mesenchymal stromal cells possess superior bioenergetic properties, highlighting their potential as an optimal source for mitochondrial transplantation therapy and providing new insights into the design of mitochondria-based therapeutics.

Recently, "readthrough compounds" have attracted attention as a promising approach to treat human hereditary diseases caused by nonsense mutations. These compounds enable ribosomes to bypass a premature termination codon (PTC) introduced into mRNA by a nonsense mutation, thereby restoring the expression of full-length functional proteins. We performed a structure-activity relationship study focusing on (+)-negamycin, a known readthrough compound, and identified potent derivatives, TCP-304 and TCP-306, featuring a cyclopropane moiety. In this study, we investigated how the nature of PTCs and their surrounding nucleotide sequences influence the readthrough activity of these negamycin derivatives, using nonsense mutation sequences derived from Duchenne muscular dystrophy and congenital muscular dystrophy genes. In cell-based reporter assay systems, TCP-306 exhibited potent readthrough efficiency against several nonsense mutation sequences containing the TGA-A. Moreover, its sequence preference differed from that of the aminoglycoside G418, a representative readthrough compound that preferentially induces readthrough at TGA-C sequences, suggesting that TCP-306 may serve as an alternative therapeutic option for muscular dystrophies associated with TGA-A nonsense mutations. Overall, this study provides valuable insights for the development of readthrough drugs for hereditary diseases such as muscular dystrophy caused by nonsense mutations.

Transglutaminases (TGs) are calcium-dependent enzymes that cross-link proteins, contributing to apoptosis, extracellular matrix (ECM) stabilization, and inflammation. While TG2 has been extensively studied in hepatic injury, the role of TG7 in oxaliplatin-induced liver responses remains unclear. Oxaliplatin, a third-generation platinum chemotherapeutic, effectively treats solid tumors but can induce hepatic stress through oxidative and pro-inflammatory signaling. Adult rats received intraperitoneal oxaliplatin (10 mg/kg weekly) for 6 weeks. qRT-PCR, immunohistochemistry (IHC), immunofluorescence (IF), and a TG activity assay assessed hepatic TG7 expression, localization, and activity. Oxidative stress indicators (serum malondialdehyde [MDA] and reduced glutathione [GSH]) and pro-inflammatory cytokine transcription (CASP3, interleukin-6 (IL-6), tumor necrosis factor α (TNF-α)) were evaluated. Oxaliplatin exposure markedly increased TG7 mRNA and protein levels, elevated TG enzymatic activity, raised MDA (+49.4%), depleted GSH (-18.6%), and upregulated CASP3, IL-6, and TNF-α. DNA fragmentation and microscopic observations from IHC- and IF-processed sections were consistent with apoptosis-associated DNA degradation and subtle stress-related structural variations. Immunostaining revealed altered TG7 distribution within hepatocytes and sinusoidal regions. In this oxaliplatin-exposed rat liver model, TG7 upregulation and increased TG activity were associated with oxidative stress, inflammatory cytokine induction, and apoptotic signaling. These findings identify TG7 as a stress-associated marker during oxaliplatin exposure and support further studies to clarify its mechanistic role and evaluate its potential as utility as a biomarker under chemotherapy-associated hepatic stress conditions.

Atherosclerosis is a pathological condition that leads to cardiovascular disease and cerebral infarction. Oxidatively modified low-density lipoprotein (LDL), known as oxidized LDL (oxLDL), is one of the major factors for atherogenesis, because it serves as a ligand for scavenger receptors. We and others developed sensitive methods to measure plasma oxLDL levels in the 1990's, and since then, mounting evidence has accumulated demonstrating the relationship between cardiovascular diseases and oxLDL in vivo. Mechanistic insights into the generation, metabolism, and modified structures of oxLDL in vivo have also been obtained. This review focuses on two key issues regarding oxLDL in vivo; its involvement in the initiation of atheromatous lesion development, and the characterization of its modified structures in vivo.

Chronic diabetic complications are mostly caused by vascular disorders, with only a few effective treatments or preventive measures currently available. In this study, we investigated the effects of Stachybotrys microspora triprenyl phenol-44D (SMTP-44D), a fungus-derived compound that inhibits both the epoxide hydrolase and phosphatase activities of soluble epoxide hydrolase (sEH), using human umbilical vein endothelial cells (HUVECs) in a high glucose treatment model. When HUVECs were treated with high glucose (30 mM) for 24 h, cell viability decreased to 69% compared with that under normal glucose (5.6 mM) conditions. When SMTP-44D was added, cell viability increased to 111%. In addition, nitric oxide levels in HUVECs decreased to 52% after 24 h of high-glucose treatment but increased to 82% after SMTP-44D treatment. Under the same conditions, high-glucose treatment increased intracellular reactive oxygen species levels and reduced Akt activation. SMTP-44D significantly improved both these changes, compared with the high glucose group. Under high glucose conditions, it is likely that oxidative stress and the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway are involved in endothelial dysfunction, and that SMTP-44D restores vascular function by acting on these pathways. In this study, we demonstrated, for the first time, SMTP-44D improves diabetic vascular endothelial dysfunction, suggesting that it may be a novel therapeutic and preventive candidate for the treatment of chronic complications of diabetes.

The effects of calcium alginate (Ca-Alg) on the suppression of blood sodium (Na⁺) concentration and blood pressure elevation in rats were investigated. In a single-dose administration test, oral administration of a 0.3% sodium chloride (NaCl) solution (5 mg/kg) resulted in a significant increase in the difference in the area under the blood Na⁺ concentration-time curve (ΔAUC). When the finest Ca-Alg particles (8 mg/body, 270 mesh) were simultaneously administered orally under the same conditions, a significant decrease in ΔAUC and a tendency for a decrease in the maximum blood concentration difference (ΔC_max) were observed. In a repeated administration test, rats were allowed to freely ingest a 3.0% Ca-Alg-containing feed for 5 weeks, and an increase in Na⁺ excretion in feces was observed. Furthermore, in spontaneously hypertensive rats (SHR), when the same Ca-Alg-containing feed was freely consumed for 15 weeks, a significant inhibition of blood pressure elevation was observed after 10 weeks. Additionally, blood biochemical tests and renal histopathological examination of these rats confirmed the safety of Ca-Alg. Based on these results, it was concluded that Ca-Alg suppresses Na⁺ absorption and blood pressure elevation in rats.

Neuregulin 1 (NRG1), a member of the epidermal growth factor (EGF) family, regulates the development, differentiation, proliferation, and plasticity in multiple tissues through its binding to ErbB3 and ErbB4 receptors. In the cardiovascular system, NRG1 plays a crucial role in cardiac development, physiological function, and cell survival. Since NRG1 exerts cardioprotective effects through its interaction with ErbB2/ErbB4 and ErbB4 homodimers on cardiomyocytes, the administration of recombinant human NRG1 has the potential for the treatment of heart failure. ErbB2 is known as human epidermal growth factor receptor 2 (HER2), which is overexpressed in approximately 20% of breast cancers. Trastuzumab (TRZ), a humanized monoclonal antibody targeting ErbB2/HER2, is used for the therapy of HER2-positive breast cancer. However, cardiotoxicity has been observed in approximately 5-10% of patients treated with TRZ. Risk factors for the onset of cardiotoxicity include the use of anthracyclines, hypertension, and diabetes. However, the mechanism linking diabetes and TRZ-induced cardiotoxicity remains unclear. Recently, we reported that the serum levels of NRG1 were elevated in the mouse model of diabetic cardiomyopathy. We found that the up-regulated NRG1 compensates for insulin deficiency to maintain systolic function in the early stage of diabetic cardiomyopathy. This review aims to discuss the physiological roles of NRG1-ErbB2 signaling in the cardiovascular system, the cardioprotective effects of NRG1 and its clinical applications, and the molecular mechanisms of TRZ-induced cardiotoxicity through the blockade of the NRG1-ErbB2 signaling pathway.

Rat kidney tissue slices are expected to be useful for an in vitro evaluation of drug-induced kidney injury (DIKI). We previously established a primary culture of rat kidney tissue slices using gas-permeable plates. However, polydimethylsiloxane (PDMS) exhibits a significant adsorption of lipophilic drugs, leading to limitations in DIKI evaluation. The aim of the present study was to evaluate a gas-permeable InnoCell™ non-treated plate made of polyolefin with low adsorption of lipophilic compounds for the primary culture of rat kidney tissue slices as an in vitro DIKI evaluation system. Drug concentrations in the medium were measured 24 h after the addition of 9 drugs to PDMS plates and InnoCell™ non-treated plates. Intra-tissue ATP levels and histopathology of rat kidney tissue slices were examined on Day 3 of culture. As a result, the InnoCell™ non-treated plates exhibited lower adsorption rates for sunitinib, cyclosporine A, and alectinib than the PDMS plates. Intra-tissue ATP levels were maintained, and immunohistochemical staining of megalin and aquaporin 1 was observed for up to 3 d. Furthermore, exposure to nephrotoxic lipophilic drugs reduced the ATP content in slices compared to that in non-treated slices. These results suggest that the primary culture of rat kidney tissue slices using InnoCell™ non-treated plates is useful for the DIKI evaluation of lipophilic drugs compared with conventional PDMS plates.