Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Volume 46, Issue 2
Displaying 1-30 of 30 articles from this issue
Current Topics - Cutting Edge Developments in RNA Biology for the Control of Gene Expression
Current Topics: Review
  • Charles Jourdan F. Reyes, Katsura Asano
    2023 Volume 46 Issue 2 Pages 139-146
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5′ untranslated region of FMR1.

Current Topics: Regular Articles
  • Kenji Tomita, Shinichi Nakagawa, Hiroyoshi Ariga, Hiroshi Maita
    2023 Volume 46 Issue 2 Pages 147-157
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Intron recognition by the spliceosome mainly depends on conserved intronic sequences such as 5′ splice sites, 3′ splice sites, and branch sites. Therefore, even substitution of just a single nucleotide in a 5′ or 3′ splice site abolishes the splicing at the mutated site and leads to cryptic splice site usage. A number of disease-causative mutations have been found in 5′ and 3′ splice sites, but the genes with these mutations still maintain the correct protein-coding sequence, so recovery of splicing at the mutated splice site may produce a normal protein. Mutations in the spliceosome components have been shown to change the balance between the conformational transition and disassembly of the spliceosome, which affects the decision about whether the reaction of the incorporated substrate will proceed. In addition, the lower disassembly rate caused by such mutations induces splicing of the mutated splice site. We hypothesized that small compounds targeting the spliceosome may include a compound mimicking the effect of those mutations. Thus, we screened a small-compound library and identified a compound, BAY61-3606, that changed the cellular small nuclear ribonucleoprotein composition and also showed activity of enhancing splicing at the mutated 3′ splice site of the reporter gene, as well as splicing at the suboptimal 3′ splice site of endogenous cassette exons. These results indicate that further analysis of the mechanism of action of BAY61-3606 could enable modulation of the fidelity of splicing.

  • Hikari Nishisaka, Takumi Tomohiro, Akira Fukao, Yoshinori Funakami, To ...
    2023 Volume 46 Issue 2 Pages 158-162
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Translation initiation is the rate-limiting step of protein synthesis and is the main target of translation regulation. RNA-binding proteins (RBPs) are key mediators of the spatiotemporal control of translation and are critical for cell proliferation, development, and differentiation. We have previously shown that HuD, one of the neuronal RBPs, enhances cap-dependent translation through the direct interaction with eukaryotic initiation factor 4A (eIF4A) and poly(A) tail using a HeLa-derived in vitro translation system. We have also found that translation stimulation of HuD is essential for HuD-induced neurite outgrowth in PC12 cells. However, it remains unclear how HuD is involved in the regulation of translation initiation. Here, we report that HuD binds to eukaryotic initiation factor 3 (eIF3) via the eIF3b subunit, which belongs to the functional core of mammalian eIF3. eIF3 plays an essential role in recruiting the 40S ribosomal subunit onto mRNA in translation initiation. We hypothesize that the interaction between HuD and eIF3 stabilizes the translation initiation complex and increases translation efficiency. We also showed that the linker region of HuD is required for the interaction with eIF3b. Moreover, we found that eIF3b-binding region of HuD is conserved in all Hu proteins (HuB, HuC, HuD, and HuR). These data might also help to explain how Hu proteins stimulate translation in a cap- and poly(A)-dependent way.

  • Ryosuke Satoh, Taemi Tanaka, Nobuyasu Yoshida, Chiaki Tanaka, Teruaki ...
    2023 Volume 46 Issue 2 Pages 163-169
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Phosphatidylinositol-4-phosphate 5-kinase (PI4P5K) is a highly conserved enzyme that generates phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) by phosphorylating phosphatidylinositol 4-phosphate (PI(4)P). Schizosaccharomyces pombe (S. pombe) its3-1 is a loss-of-function mutation in the essential its3+ gene that encodes a PI4P5K. Its3 regulates cell proliferation, cytokinesis, cell integrity, and membrane trafficking, but little is known about the regulatory mechanisms of Its3. To identify regulators of Its3, we performed a genetic screening utilizing the high-temperature sensitivity (TS) of its3-1 and identified puf3+ and puf4+, encoding Pumilio/PUF family RNA-binding proteins as multicopy suppressors of its3-1 cells. The deletions of the PUF domains in the puf3+ and puf4+ genes resulted in the reduced ability to suppress its3-1, suggesting that the suppression by Puf3 and Puf4 may involve their RNA-binding activities. The gene knockout of Puf4, but not that of Puf3, exacerbated the TS of its3-1. Interestingly, mutant Its3 expression levels both at mRNA and protein levels were lower than those of the wild-type (WT) Its3. Consistently, the overexpression of the mutant its3-1 gene suppressed the its3-1 phenotypes. Notably, Puf3 and Puf4 overexpression increased the mRNA and protein expression levels of both Its3 and Its3-1. Collectively, our genetic screening revealed a functional relationship between the Pumilio/PUF family RNA-binding proteins and PI4P5K.

Regular Articles
  • Keisuke Motoki, Tetsuya Taniguchi, Naoki Ashizawa, Miku Sakai, Noriko ...
    2023 Volume 46 Issue 2 Pages 170-176
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Uricosuric agents lower serum uric acid levels by increasing urinary excretion via inhibition of urate transporter 1 (URAT1), urate reabsorption transporter in the renal proximal tubules. Probenecid and benzbromarone have been used as uricosurics, but these drugs inhibit organic anion transporters (OATs) in addition to URAT1. In this study, we investigated whether uricosuric agents interacted with adefovir, known as a substrate for OAT1, using Sprague–Dawley (SD) rats. Furthermore, involvement of other transporters, multi-drug resistance protein 2 (MRP2) in this interaction was examined using Mrp2-deficient rats. Probenecid and lesinurad increased plasma adefovir concentrations and decreased kidney-to-plasma partition coefficient (Kp) in these rats, presumably by inhibiting Oat1. Although benzbromarone had no effect on plasma adefovir concentration, it increased the Kp to 141% in SD rats. Since this effect was abolished in Mrp2-deficient rats, together with the MRP2 inhibition study, it is suggested that benzbromarone inhibits Mrp2-mediated adefovir excretion from the kidney. In contrast, dotinurad, a novel uricosuric agent that selectively inhibits URAT1, had no effect on the plasma and kidney concentrations of adefovir. Therefore, due to the lack of interaction with adefovir, dotinurad is expected to have low drug–drug interaction risk mediated by OAT1, and also by MRP2.

  • Noria Okada, Shinsuke Nakamura, Masamitsu Shimazawa
    2023 Volume 46 Issue 2 Pages 177-186
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Huntington’s disease (HD) is a hereditary neurodegenerative disease that involves an expansion of the CAG repeats of the Huntingtin (HTT) gene, but the disease onset and progression do not necessarily correspond to the extent of CAG repeats. Decreased mitochondrial complex II activity has also been reported to be closely associated with disease pathogenesis. Here, we examined the mechanism of cell death induced by 3-nitropropionic acid (3-NP), a mitochondrial complex II inhibitor, using striatal cells (STHdhQ111 cells) derived from HD model mice with mutant HTT carrying the CAG repeat extended. Treatment with 3-NP (5 mM) enhanced cell death in STHdhQ111 compared to STHdhQ7 cells with normal HTT. Ferrostatin-1, an inhibitor of ferroptosis, and deferoxamine, an iron chelator, markedly inhibited 3-NP-induced cell death in both the STHdh cell lines. On the other hands, cell death was not abrogated by a broad-spectrum caspase inhibitor, Z-VAD-FMK, indicating that this cell death was caspase-independent. Cell death caused by 3-NP is suggested to be due to ferroptosis. Furthermore, 3-NP-induced cell death was markedly inhibited by GSK2795039, a reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) inhibitor, suggesting that cell death is mainly mediated by intracellular superoxide anion (O2) production through NOX2. Furthermore, a mitochondria-targeted superoxide dismutase mimetic (Mito-TEMPO), partially inhibited 3-NP-induced cell death, suggesting that O2 production in the mitochondria is partially responsible for cell death. These results indicate that 3-NP-induced cell death in the STHdhQ111 cells is caspase-independent, non-apoptotic, and that ferroptotic cell death is mainly induced via NOX2 activation.

  • Ning Luo, Gui-bing Chen, Teng Zhang, Jie Zhao, Jing-nan Fu, Ning Lu, T ...
    2023 Volume 46 Issue 2 Pages 187-193
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Endoplasmic reticulum (ER) dysfunction is characterized by ER stress, which can be triggered by sepsis. Recent studies have reported that lessening ER stress is a promising therapeutic approach to improving the outcome of sepsis. Genipin is derived from gardenia fruit, which is a traditional Chinese medicinal herb for anti-inflammation. Here, mice were treated with genipin (2.5 mg/kg) intravenously to assess its biological effects and underlying mechanism against polymicrobial sepsis. Furthermore, the present study focused on detecting the levels of ER stress-related proteins, including protein kinase R-like ER kinase (PERK), glucose-regulated protein of 78 kDa (GRP78), phosphorylated-eukaryotic initiation factor 2α (p-eIF2α), and CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP). The results demonstrated that genipin significantly decreased the serum concentrations of tumor necrosis factor-α and interleukin-6, alleviated histopathological damage to the lungs, livers and spleens, and even improved the survival rates of septic mice. Moreover, sepsis significantly upregulated the protein expression levels of splenic GRP78, PERK, p-eIF2α and CHOP, but their levels were significantly suppressed by genipin. Furthermore, genipin also significantly downregulated cleaved caspase-3 expression levels and reduced sepsis-induced splenocyte apoptosis. In conclusion, genipin potentially improved the survival rate of sepsis and attenuated sepsis-induced organ injury and an excessive inflammatory response in mice. The effects of genipin against sepsis were potentially associated with decreased splenocyte apoptosis via the attenuation of sepsis-induced ER stress to further inhibit ER stress-induced apoptosis.

  • Shunsaku Nakagawa, Aimi Shimazaki, Taro Funakoshi, Atsushi Yonezawa, S ...
    2023 Volume 46 Issue 2 Pages 194-200
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Higher amounts of circulating ultrafilterable platinum (fPt) are found in patients with renal dysfunction receiving a constant dose of oxaliplatin. However, the increased systemic fPt levels do not increase oxaliplatin-induced toxicities. We hypothesized that renal dysfunction has minimal effect on the elimination rate of reactive fPt, and that the DNA-binding capacity is one of the properties of reactive Pt species. This study aimed to quantify DNA-reactive fPt in plasma and to evaluate the impact of severe renal dysfunction on its pharmacokinetics. The pharmacokinetics of oxaliplatin was assessed in rats with bilateral nephrectomy (BNx) and in a hemodialysis patient who received mFOLFOX7 therapy for advanced metastatic gastric cancer. The platinum concentrations were determined using inductively coupled plasma-mass spectrometry. The amount of DNA-reactive fPt in the plasma was evaluated by the reaction between plasma and calf thymus DNA. Compared to the sham group in rats, the BNx group had significantly higher plasma total fPt concentrations at 24 h after drug administration. However, there was no significant difference in the plasma levels of DNA-reactive fPt between the two groups. In a hemodialysis patient, the plasma levels of total fPt decreased to 35.9 and 7.3% at 2 and 14 d after treatment, respectively. The plasma level of DNA-reactive fPt also decreased to 1.9 and 0.6%, respectively, on these days. This study showed that severe renal dysfunction has a limited effect on the plasma levels of DNA-reactive fPt after oxaliplatin administration.

    Editor's pick

    Oxaliplatin is a platinum (Pt)-based chemotherapeutic drug that is widely used to treat gastrointestinal and pancreatic cancers. The authors hypothesized that the DNA-binding capacity is one of the properties of reactive Pt species and aimed to evaluate the contribution of the kidney to the plasma levels of DNA-reactive Pt in an animal model and a hemodialysis patient. The results of this study showed that severe renal dysfunction has a limited effect on the plasma levels of DNA-reactive Pt after oxaliplatin administration.

  • Nao Yamamoto, Tatsuaki Tagami, Koki Ogawa, Tetsuya Ozeki
    2023 Volume 46 Issue 2 Pages 201-208
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Hospital-acquired pneumonia is an important infectious disease that requires special management and therapy for patients with compromised immunity, as opportunistic infections with microorganisms such as Pseudomonas aeruginosa can be fatal. Nanoparticle-based drug delivery to lung tissue provides several advantages in the treatment of respiratory diseases. In the current study, inhalable nanocomposite particles consisting of microparticles containing solid-state arbekacin (ABK) nanoparticles coated with hydrophobic surfactant (ABK-SD nanoparticles) were prepared using a spray dryer equipped with a two-solution mixing-type spray nozzle we previously developed. ABK-SD/mannitol (MAN) nanocomposite particles were obtained from ABK-SD nanoparticles by varying the amounts of hydrophobic surfactant and ABK. The aerosol performance of ABK-SD/MAN nanocomposite particles was superior to that of ABK-MAN microparticles in terms of the fine particle fraction (28.4 ± 5.4%, ABK-SD/MAN nanocomposite particles; 11.4 ± 7.6%, ABK-MAN microparticles). These results suggest that ABK-SD/MAN nanocomposite particles are suitable for use in inhalation drug formulations and useful for the treatment of lung infections involving Pseudomonas aeruginosa.

  • Chenhao Li, Cuizhi Geng
    2023 Volume 46 Issue 2 Pages 209-218
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Triple-negative breast cancer (TNBC) puts a great threat to women’s health. GLIS family zinc finger 3 (GLIS3) belongs to the GLI transcription factor family and acts as a critical factor in cancer progression. Nevertheless, the part of GLIS3 played in TNBC is not known. Immunohistochemical (IHC) staining analysis displayed that GLIS3 was highly expressed in TNBC tissues. The effect of GLIS3 on the malignant phenotype of TNBC was tested in two different cell lines according to GLIS3 regulation. Upregulation of GLIS3 promoted the proliferation, migration, and invasion of TNBC cell lines, whereas the knockdown of GLIS3 suppressed these tumor activities. Inhibition of GLIS3 induced TNBC cell apoptosis. Furthermore, study as immunofluorescence and electrophoretic mobility shift assay confirmed that the nuclear factor-κB (NF-κB) signaling pathway activated by GLIS3 played an important role in TNBC cells’ malignant phenotype. In conclusion, the present work demonstrated that GLIS3 acts as a crucial element in TNBC progression via activating the NF-κB signaling pathway. Accordingly, above mentioned findings indicated that modulation of GLIS3 expression is a potential tactic to interfere with the progression of TNBC.

  • Peng Tang, Yong Tang, Yan Liu, Bing He, Xin Shen, Zhi-Jie Zhang, Da-Li ...
    2023 Volume 46 Issue 2 Pages 219-229
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
    Advance online publication: December 14, 2022
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    Supplementary material

    For nearly 2000 years, Eucommia ulmoides Oliver (EUO) has been utilized in traditional Chinese medicine (TCM) throughout China. Flavonoids present in bark and leaves of EUO are responsible for their antioxidant, anti-inflammatory, antitumor, anti-osteoporosis, hypoglycemic, hypolipidemic, antibacterial, and antiviral properties, but the main bioactive compound has not been established yet. In this study, we isolated and identified quercetin glycoside (QAG) from EUO leaves (EUOL) and preliminarily explored its molecular mechanism in improving insulin resistance (IR). The results showed that QAG increased uptake of glucose as well as glycogen production in the palmitic acid (PA)-induced HepG2 cells in a dose-dependent way. Further, we observed that QAG increases glucose transporters 2 and 4 (GLUT2 and GLUT4) expression and suppresses the phosphorylation of insulin receptor substrate (IRS)-1 at serine612, thus promoting the expression of phosphatidylinositol-3-kinase (PI3K) at tyrosine458 and tyrosine199, as well as protein kinase B (Akt) and glycogen synthase kinase (GSK)-3β at serine473 and serine9, respectively. The influence posed by QAG on the improvement of uptake of glucose was significantly inhibited by LY294002, a PI3K inhibitor. In addition, the molecular docking result showed that QAG could bind to insulin receptors. In summary, our data established that QAG improved IR as demonstrated by the increased uptake of glucose and glycogen production through a signaling pathway called IRS-1/PI3K/Akt/GSK-3β.

  • Shunsuke Nashimoto, Shungo Imai, Mitsuru Sugawara, Yoh Takekuma
    2023 Volume 46 Issue 2 Pages 230-236
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    The Child–Pugh score is widely used to assess liver function and estimate drug clearance in patients with liver cirrhosis. Recently, the albumin–bilirubin (ALBI) score, which objectively assesses liver function based only on albumin and total bilirubin levels, was developed as a new method. The purpose of this study was to analyze the relationship between the liver function assessment method and the plasma concentration of voriconazole (VRCZ), an antifungal drug for patients with liver cirrhosis. This single-center retrospective study enrolled 159 patients who received VRCZ between 2012 and 2020. In patients administered VRCZ orally, the median concentration to dose (C : D) ratio increased with the progression of Child–Pugh and ALBI grades. Positive correlations between the ALBI score and VRCZ C : D ratio were observed in patients with cirrhosis (r = 0.52 (95% confidence interval, 0.069–0.79); p < 0.05). In addition, a highly negative correlation was observed between the ALBI score and VRCZ daily maintenance dose (r=−0.79 (95% confidence interval, −0.92 to −0.50); p < 0.0001). In contrast, for patients administered VRCZ intravenously, no increase in C : D ratio was observed for both Child–Pugh and ALBI scores compared to the non-liver cirrhosis group. This may be because the injection is often used in severely ill patients, and factors other than impaired liver function may affect the plasma concentrations of VRCZ. In conclusion, the ALBI score was shown to be useful in predicting VRCZ clearance as well as the Child–Pugh score, and the initial dose of VRCZ might be determined according to the ALBI score.

  • Takahiro Muro, Fumihiko Ando, Marie Suehiro, Hiroo Nakagawa, Chieko Ok ...
    2023 Volume 46 Issue 2 Pages 237-244
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
    Advance online publication: December 07, 2022
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    Community-acquired pneumonia (CAP) is an acute pulmonary parenchymal infection acquired outside the hospital. The utility of blood cultures in inpatients with CAP to reduce mortality and length of hospital stay is controversial. This study aimed to determine the utility of blood cultures on the first day of hospitalization for CAP inpatients and its influence on mortality, length of hospital stay, and antibiotics use. We conducted a fact-finding survey on the implementation of blood culture in inpatients with CAP in Japan. A propensity score (PS)-matched analysis based on the National Database of Health Insurance Claims and Specific Health Check-ups of Japan database was conducted. Overall, 163173 patients were included in the analysis, and PS matching extracted 68104 pairs. The results of the comparison between the PS-matched blood culture group and PS-matched control group were as follows: mortality and length of hospital stay were significantly lower in the PS-matched blood culture group than in the control group. The adjusted odds ratio (OR) (95% confidence interval (CI)) for in-hospital mortality with blood culture test was 0.73 (0.68–0.79). Moreover, for days of antibiotic usage, number of antibiotics used were significantly higher in the PS-matched blood culture group than that in the control group. Our findings indicated that performing a blood culture on the first day of hospitalization for inpatients with CAP was associated with reduced mortality. To our knowledge, this is the largest epidemiological study to assess the utility of blood culture in Japanese inpatients with CAP. This testing method shows potential for application in clinical practice.

  • Chiufai Kuok, Qi Wang, Pedro Fong, Yong Qin, Lirong Meng
    2023 Volume 46 Issue 2 Pages 245-256
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Hepatocellular carcinoma (HCC) causes 830000 deaths every year and is becoming the third malignant tumor worldwide. One of the primary reasons is the lack of effective drugs. Hernandezine (HER), a bisbenzylisoquinoline alkaloid of Thalictrum simplex, has been confirmed to have antitumor activity. But there are few reports about its effect on HCC and the underlying mechanisms still remain unclear. Therefore, the antitumor effects and mechanisms of HER on HCC were evaluated in HepG2 and Hep3B cells. The in vitro experiments demonstrated that HER significantly induced G0/G1 phase arrest, inhibited the proliferation and promoted cell apoptosis in liver cancer cell lines. In the mechanisms, the antitumor effects of HER on liver cancer cells were mediated by phosphatidylinositol 3-kinase (PI3K)–protein kinase B (AKT) pathway and reactive oxygen species (ROS), simultaneously. In one way, HER inhibited the activities of PI3K–AKT pathway, which interrupt the dimer formation of cyclin-dependent kinase 4 (CDK4) and cyclin D1 (CCND1) and result to G0/G1 phase arrest. In another way, after HER treatment, ROS accumulated in liver cancer cells and caused mitochondria injury which further influenced the expression of apoptosis-related proteins and eventually resulted to HepG2 and Hep3B cell apoptosis. In addition, HER showed a tumor restrain function in HepG2 and Hep3B bearing nude mice. Overall, these findings indicated that HER is a promising antitumor drug, which may provide a new direction for clinical HCC treatment.

  • Yasuhiro Nakamura, Fumiko Kihara-Negishi, Kazunari Tanigawa, Mitsuo Ki ...
    2023 Volume 46 Issue 2 Pages 257-262
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Platelet-activating factor acetylhydrolase (PAF-AH) hydrolyzes an acetyl ester at the sn-2 position of platelet-activating factor (PAF), thereby mediating a variety of biological functions. PAF-AH is found in three isoforms: Type I PAF-AH (PAF-AH I) and Type II PAF-AH (PAF-AH II) are intracellular enzymes whereas plasma PAF-AH is characterized by association with lipoprotein in plasma. PAF-AH I forms a tetramer constituted by two catalytic subunits (α1 and α2) with β regulatory subunits. We recently showed that a deficiency of PAF-AH I catalytic subunits in male mice caused an increase of body weight, food intake, and white adipose tissue (WAT) weight. In this study, we examined whether the expression of this enzyme was altered in the differentiation of 3T3-L1 preadipocytes into adipocytes. The amount of PAF-AH I α1 subunit protein was significantly reduced in 3T3-L1 differentiation, while the amount of the PAF-AH I α2 subunit was not changed. Immunoprecipitation analysis of 3T3-L1 differentiation showed that the complex of PAF-AH I catalytic subunits was changed from α1/α2 heterodimer to α2/α2 homodimer. Our findings suggest that changes in PAF-AH I catalytic subunits are involved in adipocyte differentiation of 3T3-L1 and obesity in mice.

  • Mayumi Mimura, Yoshihiko Koizumi, Masashi Wada, Tomoaki Ichijo, Kimiko ...
    2023 Volume 46 Issue 2 Pages 263-271
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Private wells are used daily worldwide as convenient household water sources. In Japan, where water supply coverage is high, well water is occasionally used for non-potable purposes, such as irrigation and watering. Currently, the main microbiological test of well water is designed to detect Escherichia coli, which is an indicator of fecal contamination, using culture methods. Water use such as watering generates bioaerosols, which may cause airborne infection. However, many causative bacteria of aerosol-derived infections, such as Legionella spp., are difficult to detect using culture methods. Thus, more comprehensive modern assessment is desirable for securing the microbiological quality of well water. Here, the bacterial community structure of five private wells located in different environments was examined using the rapid and portable MinION sequencer, which enabled us to identify bacteria to the species level based on full-length 16S ribosomal RNA (rRNA) gene sequences. The results revealed the differences in the bacterial community structures of water samples from the five wells and detected Legionella pneumophila and Aeromonas hydrophila as new candidate microbial indicators. The comprehensive analysis method used in this study successfully detected bacteria causing opportunistic infections, which are difficult to detect by conventional methods. This approach is expected to be routinely applied in the future as a highly accurate method for assessing the microbiological quality of private well water.

    Editor's pick

    Private wells are used daily worldwide as convenient household water sources. Comprehensive modern assessment is desirable for securing the microbiological quality of well water. Here, the bacterial community structure was examined using the rapid and portable MinION sequencer, which enabled us to identify bacteria to the species level based on full-length 16S rRNA gene sequences. The analysis method successfully detected bacteria causing opportunistic infections, which are difficult to detect by conventional methods. This approach is expected to be routinely applied in the future as a highly accurate method for assessing the microbiological quality of private well water.

  • Masato Noda, Chigusa Kikuchi, Ryota Tarui, Takashi Nakamura, Takayo Mu ...
    2023 Volume 46 Issue 2 Pages 272-278
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
    Advance online publication: December 16, 2022
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    Xanthine oxidoreductase exists both intracellularly and extracellularly and induces vascular injury by producing reactive oxygen species (ROS). Here, we investigated the effects and mechanism of action of topiroxostat, a xanthine oxidase inhibitor, on ROS using an animal model of type 1 diabetes with persistent hyperglycemia. Six-week-old male Sprague–Dawley rats were administered 50 mg/kg streptozotocin to induce diabetes; at 8 weeks of age, animals were administered topiroxostat (0.3, 1, or 3 mg/kg) for 2 weeks through mixed feeding after which the aorta was sampled. The production of superoxide, a type of ROS, was measured by chemiluminescence and dihydroethidium staining. Cytotoxicity was evaluated by nitrotyrosine staining. Topiroxostat at 3 mg/kg significantly decreased blood urea nitrogen, e-selectin, urinary malondialdehyde, and the urinary albumin/creatinine ratio compared with the streptozotocin group. Superoxide production by xanthine oxidase anchored to the cell membrane was significantly decreased by topiroxostat at both 1 mg/kg and 3 mg/kg compared with the streptozotocin group. Dihydroethidium staining revealed no significant effect of topiroxostat administration on superoxide production. The fluorescence intensity of nitrotyrosine staining was significantly suppressed by 3 mg/kg topiroxostat. Topiroxostat was found to inhibit the production of ROS in the thoracic aorta and suppress vascular endothelial damage. The antioxidant effect of topiroxostat appears to be exerted via the inhibition of anchored xanthine oxidase.

    Editor's pick

    Vascular damage is often seen in patients with diabetes and is thought to be caused by oxidative stress. Xanthine oxidoreductase exists both intracellularly and extracellularly and causes vascular injury by producing reactive oxygen species. The authors investigated the effects of topiroxostat, a xanthine oxidase inhibitor, and its mechanism of action in a rodent model of diabetes. They found that topiroxostat inhibited anchored xanthine oxidase bound to the surface of vascular endothelial cells in the thoracic aorta and suppressed damage to these cells, suggesting that topiroxostat could potentially have a vasoprotective effect in patients with diabetes-induced macrovascular disease.

  • Ayano Sawa-Aihara, Katsuji Hattori, Goshi Nagao, Yoshihisa Yamada, Tat ...
    2023 Volume 46 Issue 2 Pages 279-285
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Renal fibrosis is scarring and tissue hardening caused by the excess deposition of extracellular matrix proteins in response to chronic inflammation. Renal fibrosis is the primary cause of a progressive loss of renal function, and is an important therapeutic target because it ultimately leads to end-stage renal failure, which can be treated only by either dialysis or kidney transplantation. There is no effective treatment that specifically targets renal fibrosis. Myofibroblasts are known to evade apoptosis by activating molecular mechanisms in response to pro-survival biomechanical and growth factor signals from the fibrotic microenvironment. In this study, we screened and selected compounds that selectively cause cell death in myofibroblasts in vitro and studied their possible potency against renal fibrosis in a mouse model. Several proteasome inhibitors induced selective cell death in myofibroblasts differentiated from the human fibroblast cell line (MRC5). The in vivo antifibrotic effect of Delanzomib (Dz), one of the proteasome inhibitors most sensitive to myofibroblasts in vitro, was investigated in a Unilateral Ureteric Obstruction (UUO) mouse model. Treatment with Dz decreased the expression levels of the actin-alpha-2 (ACTA2) and collagen-type-1-alpha-1 (COL1A1) genes in the kidney, which are common fibrosis markers. These results suggest that Dz might be a compound that suppresses renal fibrosis by inducing selective cell death of myofibroblasts, although further investigation is required.

  • Satoko Notomi, Mineaki Kitamura, Kosei Yamaguchi, Maya Komine, Kenji S ...
    2023 Volume 46 Issue 2 Pages 286-291
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Anorexia is a common symptom in older patients undergoing hemodialysis (HD) and has become a serious problem in dialysis facilities with the aging of patients. Polypharmacy, defined as the prescription of several medications, is known to cause drug-induced anorexia. Although polypharmacy is also common in older patients undergoing HD, only a few studies have examined the association between anorexia and polypharmacy. This study used the Simplified Nutritional Appetite Questionnaire for Japanese Elderly (SNAQ-JE) to evaluate patients’ appetite, and examined its association with medications. This cross-sectional study included 233 patients (aged ≥65 years) who underwent HD in October 2021. Among the 233 patients (median age, 73.0 [interquartile range (IQR), 69.0–80.5] years; men, 57.3%; median dialysis vintage, 62.0 [IQR, 30.0–122.0] months), 116 and 117 were classified into the poor (SNAQ-JE total score ≤14) and good (>14) appetite groups, respectively. Although the total number of medications prescribed was not significantly different between the two groups (p = 0.12), the number of antihypertensive drugs was significantly lower (p = 0.03), and that of sleeping medications was significantly higher (p = 0.002) in the poor appetite group. Multivariable logistic regression analysis showed that the number of sleeping medications was associated with poor appetite (odds ratio, 2.08; 95% confidence interval, 1.32–3.27; p < 0.001). The findings suggest that the number of sleeping medications is an important contributing factor to poor appetite in older patients undergoing HD. A proper and regular review of prescriptions may be necessary to improve anorexia.

  • Keishi Ishida, Kazuki Takeda, Yuki Takehara, Tomoki Takabayashi, Masat ...
    2023 Volume 46 Issue 2 Pages 292-300
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Methylmercury (MeHg) is a well-known environmental pollutant that has harmful effects on the central nervous systems of humans and animals. The molecular mechanisms of MeHg-induced neurotoxicity at low concentrations are not fully understood. Here, we investigated the effects of low-concentration MeHg on the cell viability, Ca2+ homeostasis, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA2 levels, which determine Ca2+ permeability of AMPA receptors, in rat primary cortical neurons. Exposure of cortical neurons to 100 and 300 nM MeHg for 7 d resulted in a decrease in GluA2 levels, an increase in basal intracellular Ca2+ concentration, increased phosphorylation levels of extracellular signal-regulated kinase (ERK)1/2 and p38, and decreased cell viability. Moreover, glutamate stimulation exacerbated the decrease in cell viability and increased intracellular Ca2+ levels in MeHg-treated neurons compared to control neurons. MeHg-induced neuronal cell death was ameliorated by 1-naphthyl acetyl spermine, a specific antagonist of Ca2+-permeable, GluA2-lacking AMPA receptors. Our findings raise the possibility that decreased neuronal GluA2 levels and the subsequent increase in intracellular Ca2+ concentration may contribute to MeHg-induced neurotoxicity.

  • Rabab A. Husseini, Naoko Abe, Tomoaki Hara, Hiroshi Abe, Kentaro Kogur ...
    2023 Volume 46 Issue 2 Pages 301-308
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    mRNA vaccines have attracted considerable attention as a result of the 2019 coronavirus pandemic; however, challenges remain regarding use of mRNA vaccines, including insufficient delivery owing to the high molecular weights and high negative charges associated with mRNA. These characteristics of mRNA vaccines impair intracellular uptake and subsequent protein translation. In the current study, we prepared a minimal mRNA vaccine encoding a tumor associated antigen human gp10025–33 peptide (KVPRNQDWL), as a potential treatment for melanoma. Minimal mRNA vaccines have recently shown promise at improving the translational process, and can be prepared via a simple production method. Moreover, we previously reported the successful use of iontophoresis (IP) technology in the delivery of hydrophilic macromolecules into skin layers, as well as intracellular delivery of small interfering RNA (siRNA). We hypothesized that combining IP technology with a newly synthesized minimal mRNA vaccine can improve both transdermal and intracellular delivery of mRNA. Following IP-induced delivery of a mRNA vaccine, an immune response is elicited resulting in activation of skin resident immune cells. As expected, combining both technologies led to potent stimulation of the immune system, which was observed via potent tumor inhibition in mice bearing melanoma. Additionally, there was an elevation in mRNA expression levels of various cytokines, mainly interferon (IFN)-γ, as well as infiltration of cytotoxic CD8+ T cells in the tumor tissue, which are responsible for tumor clearance. This is the first report demonstrating the application of IP for delivery of a minimal mRNA vaccine as a potential melanoma therapeutic.

    Editor's pick

    mRNA has many challenges including insufficient delivery owing to the high molecular weight and high negative charge. Authors chemically synthesized a minimal mRNA vaccine encoding human gp10025-33 peptide (KVPRNQDWL), as a potential treatment for melanoma and iontophoresis (IP) was used for its delivery into the skin. After combining IP with the newly synthetized minimal mRNA vaccine, successful intradermal and intracellular delivery of the minimal mRNA was achieved. Results showed stimulation of the immune system which led to tumor inhibition and infiltration of cytotoxic CD8+ T cells in the tumor tissue. This is the first report combining IP and chemically synthesized minimal mRNA vaccine.

  • Keisuke Obara, Kento Yoshioka, Montserrat De Dios Regadera, Yusuke Mat ...
    2023 Volume 46 Issue 2 Pages 309-319
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    We examined whether the α1L-adrenoceptor (AR), which shows low affinity (pA2 < 9) for prazosin (an α1-AR antagonist) and high affinity (pA2 ≈ 10) for tamsulosin/silodosin (α1A-AR antagonists), is involved in phenylephrine-induced contractions in the guinea pig (GP) thoracic aorta (TA). Intracellular signaling induced by α1L-AR activation was also examined by focusing on Ca2+ influx pathways. Tension changes of endothelium-denuded TAs were isometrically recorded and mRNA encoding α-ARs/Ca2+ channels and their related molecules were measured using RT-quantitative PCR. Phenylephrine-induced contractions were competitively inhibited by prazosin/tamsulosin, and their pA2 value were calculated to be 8.53/9.74, respectively. These contractions were also inhibited by silodosin concentration-dependently. However, the inhibition was not competitive fashion with the apparent pA2 value being 9.48. In contrast, phenylephrine-induced contractions were not substantially suppressed by L-765314 (an α1B-AR antagonist), BMY 7378 (an α1D-AR antagonist), yohimbine, and idazoxan (α2-AR antagonists). Phenylephrine-induced contractions were markedly inhibited by YM-254890 (a Gq protein inhibitor) or removal of extracellular Ca2+, and partially inhibited by verapamil (a voltage-dependent Ca2+ channel (VDCC) inhibitor). The residual contractions in the presence of verapamil were slightly inhibited by LOE 908 (a receptor-operated Ca2+ channel (ROCC) inhibitor) and strongly inhibited by SKF-96365 (a store-operated Ca2+ channel (SOCC) and ROCC inhibitor). Among the mRNA encoding α-ARs/SOCC-related molecules, α1A-AR (Adra1a)/Orai3, Orai1, and Stim2 were abundant in this tissue. In conclusion, phenylephrine-induced contractions in the GP TA can be triggered by stimulation of Gq protein-coupled α1L-AR, followed by activation of SOCCs and VDCCs.

  • Aina Fukuda, Souichi Nakashima, Yoshimi Oda, Kaneyasu Nishimura, Hidek ...
    2023 Volume 46 Issue 2 Pages 320-333
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by dementia. The most characteristic pathological changes in AD brain include extracellular amyloid-β (Aβ) accumulation and neuronal loss. Particularly, cholinergic neurons in the nucleus basalis of Meynert are some of the first neuronal groups to degenerate; accumulating evidence suggests that Aβ oligomers are the primary form of neurotoxicity. Bacopa monniera is a traditional Indian memory enhancer whose extract has shown neuroprotective and Aβ-reducing effects. In this study, we explored the low molecular weight compounds from B. monniera extracts with an affinity to Aβ aggregates, including its oligomers, using Aβ oligomer-conjugated beads and identified plantainoside B. Plantainoside B exhibited evident neuroprotective effects by preventing Aβ attachment on the cell surface of human induced pluripotent stem cell (hiPSC)-derived cholinergic neurons. Moreover, it attenuated memory impairment in mice that received intrahippocampal Aβ injections. Furthermore, radioisotope experiments revealed that plantainoside B has affinity to Aβ aggregates including its oligomers and brain tissue from a mouse model of Aβ pathology. In addition, plantainoside B could delay the Aβ aggregation rate. Accordingly, plantainoside B may exert neuroprotective effects by binding to Aβ oligomers, thus interrupting the binding of Aβ oligomers to the cell surface. This suggests its potential application as a theranostics in AD, simultaneously diagnostic and therapeutic drugs.

    Editor's pick

    Cholinergic neurons in the basal forebrain are known to degenerate early stage of Alzheimer's disease (AD), and amyloid-β (Aβ) oligomers are suggested to be deeply involved in AD pathogenesis. Authors here established an Aβ oligomer-induced neurodegeneration model using human induced pluripotent stem cell-derived cholinergic neurons and demonstrated the neuroprotective effect of plantainoside B identified from herbal extracts as an Aβ-binding small molecule. Radioisotope-labeled plantainoside B showed affinities to Aβ oligomers and brain sections from a mouse model of AD. Results suggest the potential of developing “theranostics” in AD that simultaneously performs diagnoses (Aβ detection) and therapy (neuroprotection).

Notes
  • Kohei Matsuo, Yumi Abiko, Shigeru Yamano, Kimihiko Matsusue, Yoshito K ...
    2023 Volume 46 Issue 2 Pages 334-337
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Morphinone (MO) is an electrophilic metabolite of morphine that covalently binds to protein thiols, resulting in toxicity in vitro and in vivo. We have previously identified a variety of redox signaling pathways that are activated during electrophilic stress. However, the role of MO in such activation remains unknown. In this study, we examined whether MO could activate heat shock protein (HSP) 90/heat shock factor (HSF) 1 signaling in HepG2 cells. MO exposure caused S-modification of HSP90 (determined using biotin-PEAC5-maleimide labeling) and nuclear translocation of transcription factor HSF1, thereby up-regulating its downstream genes encoding B-cell lymphoma 2-associated anthanogene 3 and heat shock 70 kDa protein 1. However, dihydromorphinone, a non-electrophilic metabolite of morphine, had little effect on HSF1 activation or upregulation of these genes, suggesting that covalent modification plays a role in this process and that the HSP90/HSF1 pathway is a redox-signaled adaptive response to morphine metabolism.

  • Kohei Matsuo, Yumi Abiko, Shigeru Yamano, Akira Toriba, Kimihiko Matsu ...
    2023 Volume 46 Issue 2 Pages 338-342
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Morphinone (MO) is an electrophilic metabolite of morphine that covalently binds to protein thiols via its α,β-unsaturated carbonyl group, resulting in toxicity in vitro and in vivo. Our previous studies identified a variety of redox signaling pathways that are activated during electrophilic stress. Here, we examined in vitro activation of a signaling pathway involving Kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) in response to MO. Exposure of HepG2 cells to MO caused covalent modification of Keap1 thiols (evaluated using biotin-PEAC5-maleimide labeling) and nuclear translocation of Nrf2, thereby up-regulating downstream genes encoding ATP binding cassette subfamily C member 2, solute carrier family 7 member 11, glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase modifier subunit, glutathione S-transferase alpha 1, and heme oxygenase 1. However, dihydromorphinone, a metabolite of morphine lacking the reactive C7–C8 double bond, had little effect on Nrf2 activation. These results suggest that covalent modification is crucial in the Keap1/Nrf2 pathway activation and that this pathway is a redox signaling-associated adaptive response to MO metabolism.

  • Risako Morishita, Miki Shimada, Minami Nagao, Shin Shimizu, Noriyasu K ...
    2023 Volume 46 Issue 2 Pages 343-347
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Owing to their unique physicochemical properties and diverse biological effects, ultrafine bubbles (UFBs) have recently been expected to be utilized for industrial and biological purposes. Thus, this study investigated the biological safety of UFBs in water for living beings in drinking the water with a view to future use in health sciences. In this study, we used H2-filled UFBs (NanoGAS®) that can hold hydrogen in the aqueous phase for a long time. Mice were randomly assigned to one of three groups: those receiving NanoGAS® water, reverse osmosis water, or natural mineral water, and they ingested it ad libitum for one month or three months. As a result, subchronic drinking of NanoGAS® water does not affect either the common blood biochemical parameters or the health of the organs and mucosal membranes. Our results, for the first time, scientifically demonstrated the biological safety of H2-filled UFBs water for subchronic oral consumption.

  • Jiajun Lyu, Takuya Kubo, Sayuki Iwahashi, Kazuya Fukasawa, Tetsuhiro H ...
    2023 Volume 46 Issue 2 Pages 348-353
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Royal jelly (RJ), an essential food for the queen honeybee, has a variety of biological activities. Although RJ exerts preventive effects on various lifestyle-related diseases, such as osteoporosis and obesity, no study evaluated the effect of RJ on the development of osteoarthritis (OA), the most common degenerative joint disease. Here, we showed that daily oral administration of raw RJ significantly prevented OA development in vivo following surgically-induced knee joint instability in mice. Furthermore, in vitro experiments using chondrocytes, revealed that raw RJ significantly reduced the expression of inflammatory cytokines and enzymes critical for the degradation of the extracellular matrix (ECM). Similar results were observed after treatment with 10-hydroxy-2-decenoic acid, the most abundant and unique fatty acid in raw RJ. Our results suggest that oral supplementation with RJ would benefit the maintenance of joint health and prophylaxis against OA, possibly by suppressing the activity of inflammatory cytokines and ECM-degrading enzymes.

  • Keisuke Obara, Yuka Matsuoka, Naoya Iwata, Yukako Abe, Yohei Ikegami, ...
    2023 Volume 46 Issue 2 Pages 354-358
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Supplementary material

    Dimethyl sulfoxide (DMSO) has been used not only as an experimental solvent, but also as a therapeutic agent for interstitial cystitis. The therapeutic effects of DMSO on interstitial cystitis are presumed to involve anti-inflammatory and analgesic effects. However, the effects of DMSO on urinary bladder smooth muscle (UBSM) have not been fully investigated. Thus, in this study, we investigated the effects of DMSO on rat UBSM contractions, and these effects were compared with those of acetone, which has a structure in which the sulfur of DMSO is replaced with carbon. DMSO (0.5–5%) enhanced acetylcholine (ACh)-induced contractions, whereas acetone (3 and 5%) suppressed them. Additionally, DMSO (5%) suppressed carbachol-induced contractions. DMSO/acetone (0.5–5%) inhibited 80 mM KCl-induced contractions in a concentration-dependent manner; however, the inhibitory effects of DMSO were weaker than those of acetone. The enhancing/suppressing effects of DMSO and acetone were almost completely abolished by wash out. DMSO and acetone (0.5–5%) inhibited recombinant human acetylcholinesterase (rhAChE) activity in a concentration-dependent manner. At 0.5 and 1%, the inhibitory effects of DMSO on rhAChE activity were more potent than those of acetone. These findings suggest that DMSO can enhance ACh-induced UBSM contractions and promote urinary bladder motility by inhibiting acetylcholinesterase (AChE), although DMSO also inhibits Ca2+ influx-mediated UBSM contractions. In addition, the sulfur atom in DMSO might play an important role in its enhancing effect on ACh-induced contractions by inhibiting AChE, as acetone did not enhance these contractions.

  • Takahito Maki, Masahito Sawahata, Daisuke Uta, Kazuhiro Irie, Toshiaki ...
    2023 Volume 46 Issue 2 Pages 359-363
    Published: February 01, 2023
    Released on J-STAGE: February 01, 2023
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    Amyloid β (Aβ) plays a key role in the pathology of Alzheimer’s disease (AD) and is toxic owing to its ability to aggregate into oligomers and fibrils. Aβ has high aggregative ability and potent toxicity due to the “toxic turn” at positions 22 and 23. Furthermore, APP knock-in mice producing E22P-Aβ with the toxic turn exhibited AD-related phenotypes such as cognitive impairment, Aβ plaque accumulation, and tau hyperphosphorylation. In these mice, it is suggested that the activation of neuroinflammation and dysregulation of hypoxia-inducible factor (HIF) expression in the hippocampus contribute to the pathogenesis of AD-related phenotype. However, it remains unclear which cells are responsible for the dysregulation of HIF expression and the neuroinflammation which was induced by E22P-Aβ with the toxic turn. Here, we investigated the effects of chronic treatment with E22P-Aβ42 and lipopolysaccharides (LPS) on the inflammatory response in BV-2 microglia. Chronic treatment with E22P-Aβ42 and LPS increased nitric oxide production and the expression of interleukin-6 (IL-6), whereas it reduced the expression of HIF-1α and HIF-3α in BV-2 microglia. The reduction of HIF-1α caused by E22P-Aβ42 and LPS was milder than that caused by LPS. Furthermore, chronic treatment with E22P-Aβ42 and LPS increased the nuclear translocation of nuclear factor-kappaB (NF-κB). E22P-Aβ42 could enhance the inflammatory response of microglia with abnormal HIF signaling and contribute to the progression of AD pathology.

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