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9. The NOX1 isoform of NADPH oxidase is involved in dysfunction of liver sinusoids in nonalcoholic fatty liver disease.

Author

Matsumoto, Misaki, Zhang, Jia, Zhang, Xueqing, Liu, Junjie, Jiang, Joy, Yamaguchi, Kanji, Taruno, Akiyuki, Katsuyama, Masato, Iwata, Kazumi, Ibi, Masakazu, Cui, Wenhao, Matsuno, Kuniharu, Marunaka, Yoshinori, Itoh, Yoshito, Torok, Natalie, and Yabe-Nishimura, Chihiro

Subjects
Liver sinusoidal endothelial cells (LSECs), Nitric oxide (NO), Nitrotyrosine, Nonalcoholic fatty liver disease (NAFLD), Reactive oxygen species (ROS), Alanine Transaminase, Animals, Capillaries, Cell Line, Diet, High-Fat, Disease Models, Animal, Humans, Liver, Male, Mice, Mice, Knockout, NADPH Oxidase 1, NADPH Oxidases, Non-alcoholic Fatty Liver Disease, Reactive Oxygen Species, Up-Regulation
Abstract

The increased production of reactive oxygen species (ROS) has been postulated to play a key role in the progression of nonalcoholic fatty liver disease (NAFLD). However, the source of ROS and mechanisms underlying the development of NAFLD have yet to be established. We observed a significant up-regulation of a minor isoform of NADPH oxidase, NOX1, in the liver of nonalcoholic steatohepatitis (NASH) patients as well as of mice fed a high-fat and high-cholesterol (HFC) diet for 8 weeks. In mice deficient in Nox1 (Nox1KO), increased levels of serum alanine aminotransferase and hepatic cleaved caspase-3 demonstrated in HFC diet-fed wild-type mice (WT) were significantly attenuated. Concomitantly, increased protein nitrotyrosine adducts, a marker of peroxynitrite-induced injury detected in hepatic sinusoids of WT, were significantly suppressed in Nox1KO. The expression of NOX1 mRNA was much higher in the fractions of enriched liver sinusoidal endothelial cells (LSECs) than in those of hepatocytes. In primary cultured LSECs, palmitic acid (PA) up-regulated the mRNA level of NOX1, but not of NOX2 or NOX4. The production of nitric oxide by LSECs was significantly attenuated by PA-treatment in WT but not in Nox1KO. When the in vitro relaxation of TWNT1, a cell line that originated from hepatic stellate cells, was assessed by the gel contraction assay, the relaxation of stellate cells induced by LSECs was attenuated by PA treatment. In contrast, the relaxation effect of LSECs was preserved in cells isolated from Nox1KO. Taken together, the up-regulation of NOX1 in LSECs may elicit peroxynitrite-mediated cellular injury and impaired hepatic microcirculation through the reduced bioavailability of nitric oxide. ROS derived from NOX1 may therefore constitute a critical component in the progression of NAFLD.

Published
2018

16. Ciliary Motility Decreased by a CO 2 /HCO 3 − -Free Solution in Ciliated Human Nasal Epithelial Cells Having a pH Elevated by Carbonic Anhydrase IV.

Author

Okamoto, Shota, Yasuda, Makoto, Kawaguchi, Kotoku, Yasuoka, Kasane, Kikukawa, Yumi, Asano, Shinji, Tsujii, Taisei, Inoue, Sana, Amagase, Kikuko, Inui, Taka-aki, Hirano, Shigeru, Inui, Toshio, Marunaka, Yoshinori, and Nakahari, Takashi

Subjects
CARBONIC anhydrase, EPITHELIAL cells, CARBON dioxide, CILIA & ciliary motion, BICARBONATE ions, RESPIRATION
Abstract

An application of CO2/HCO3−-free solution (Zero-CO2) did not increase intracellular pH (pHi) in ciliated human nasal epithelial cells (c-hNECs), leading to no increase in frequency (CBF) or amplitude (CBA) of the ciliary beating. This study demonstrated that the pHi of c-hNECs expressing carbonic anhydrase IV (CAIV) is high (7.64), while the pHi of ciliated human bronchial epithelial cells (c-hBECs) expressing no CAIV is low (7.10). An extremely high pHi of c-hNECs caused pHi, CBF and CBA to decrease upon Zero-CO2 application, while a low pHi of c-hBECs caused them to increase. An extremely high pHi was generated by a high rate of HCO3− influx via interactions between CAIV and Na+/HCO3− cotransport (NBC) in c-hNECs. An NBC inhibitor (S0859) decreased pHi, CBF and CBA and increased CBF and CBA in c-hNECs upon Zero-CO2 application. In conclusion, the interactions of CAIV and NBC maximize HCO3− influx to increase pHi in c-hNECs. This novel mechanism causes pHi to decrease, leading to no increase in CBF and CBA in c-hNECs upon Zero-CO2 application, and appears to play a crucial role in maintaining pHi, CBF and CBA in c-hNECs periodically exposed to air (0.04% CO2) with respiration. [ABSTRACT FROM AUTHOR]

Published
2024
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17. The Increase in the Frequency and Amplitude of the Beating of Isolated Mouse Tracheal Cilia Reactivated by ATP and cAMP with Elevation in pH.

Author

Kobayashi, Akari, Kawaguchi, Kotoku, Asano, Shinji, Wu, Hong, Nakano, Takashi, Inui, Toshio, Marunaka, Yoshinori, and Nakahari, Takashi

Subjects
VIDEO microscopy, TRITON X-100, CILIA & ciliary motion, PH effect, CANNABIDIOL
Abstract

Single cilia, 100 nm in diameter and 10 µm in length, were isolated from mouse tracheae with Triton X-100 (0.02%) treatment, and the effects of pH on ciliary beating were examined by measuring the ciliary beat frequency (CBF) and the ciliary bend distance (CBD—an index of amplitude) using a high-speed video microscope (250 fps). ATP (2.5 mM) plus 8Br-cAMP (10 µM) reactivated the CBF and CBD in the isolated cilia, similar to the cilia of in vivo tracheae. In the reactivated isolated cilia, an elevation in pH from 7.0 to 8.0 increased the CBF from 3 to 15 Hz and the CBD from 0.6 to 1.5 µm. The pH elevation also increased the velocity of the effective stroke; however, it did not increase the recovery stroke, and, moreover, it decreased the intervals between beats. This indicates that H+ (pHi) directly acts on the axonemal machinery to regulate CBF and CBD. In isolated cilia priorly treated with 1 µM PKI-amide (a PKA inhibitor), 8Br-cAMP did not increase the CBF or CBD in the ATP-stimulated isolated cilia. pH modulates the PKA signal, which enhances the axonemal beating generated by the ATP-activated inner and outer dyneins. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Nasal ciliary beating controlled by carbonic anhydrase IV and Na+/HCO3- co-transport under an extremely low CO2 condition (air)

Author

Okamoto, Shota, primary, Yasuda, Makoto, additional, Kawaguchi, Kotoku, additional, Yasuoka, Kasane, additional, Kikukawa, Yumi, additional, Asano, Shinji, additional, Inui, Taka-aki, additional, Hirano, Shigeru, additional, Inui, Toshio, additional, Marunaka, Yoshinori, additional, and Nakahari, Takashi, additional

Published
2023
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37. Ambroxol-Enhanced Frequency and Amplitude of Beating Cilia Controlled by a Voltage-Gated Ca 2+ Channel, Cav1.2, via pH i Increase and [Cl − ] i Decrease in the Lung Airway Epithelial Cells of Mice.

Author

Nakahari, Takashi, Suzuki, Chihiro, Kawaguchi, Kotoku, Hosogi, Shigekuni, Tanaka, Saori, Asano, Shinji, Inui, Toshio, and Marunaka, Yoshinori

Subjects
CALCIUM ions, EPITHELIAL cells, CILIA & ciliary motion, LUNGS, MICE, CELL size
Abstract

Ambroxol (ABX), a frequently prescribed secretolytic agent which enhances the ciliary beat frequency (CBF) and ciliary bend angle (CBA, an index of amplitude) by 30%, activates a voltage-dependent Ca2+ channel (CaV1.2) and a small transient Ca2+ release in the ciliated lung airway epithelial cells (c-LAECs) of mice. The activation of CaV1.2 alone enhanced the CBF and CBA by 20%, mediated by a pHi increasei and a [Cl−]i decrease in the c-LAECs. The increase in pHi, which was induced by the activation of the Na+-HCO3− cotransporter (NBC), enhanced the CBF (by 30%) and CBA (by 15–20%), and a decrease in [Cl−]i, which was induced by the Cl− release via anoctamine 1 (ANO1), enhanced the CBA (by 10–15%). While a Ca2+-free solution or nifedipine (an inhibitor of CaV1.2) inhibited 70% of the CBF and CBA enhancement using ABX, CaV1.2 enhanced most of the CBF and CBA increases using ABX. The activation of the CaV1.2 existing in the cilia stimulates the NBC to increase pHi and ANO1 to decrease the [Cl−]i in the c-LAECs. In conclusion, the pHi increase and the [Cl−]i decrease enhanced the CBF and CBA in the ABX-stimulated c-LAECs. [ABSTRACT FROM AUTHOR]

Published
2023
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38. Mumefural prevents insulin resistance and amyloid-beta accumulation in the brain by improving lowered interstitial fluid pH in type 2 diabetes mellitus

Author

Hosogi, Shigekuni, primary, KUWAHARA, Atsukazu, additional, KUWAHARA, Yuko, additional, TANAKA, Saori, additional, SHIMAMOTO, Chikao, additional, TAGAWA, Noriko, additional, KATO, Ikuo, additional, YOSHIMOTO, Kanji, additional, AOI, Wataru, additional, TAKATA, Kazuyuki, additional, MIYAZAKI, Hiroaki, additional, NIISATO, Naomi, additional, TSUBO, Yasuhiro, additional, YAGI, Katsumi, additional, NAKAHARI, Takashi, additional, and MARUNAKA, Yoshinori, additional

Published
2023
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