bims-noxint 2021-05-30 papers

Issue of 2021–05–30
five papers selected by
Laia Caja Puigsubira, Uppsala University

J Biol Chem. 2021 May 20. pii: S0021-9258(21)00605-0. [Epub ahead of print] 100810

NOX4 regulates macrophage apoptosis resistance to induce fibrotic progression.

Jennifer L Larson-Casey, Linlin Gu, Jungsoon Kang, Ashish Dhyani, A Brent Carter.

Pulmonary fibrosis is a progressive lung disease often occurring secondary to environmental exposure. Asbestos exposure is an important environmental mediator of lung fibrosis and remains a significant cause of disease despite strict regulations to limit exposure. Lung macrophages play an integral role in the pathogenesis of fibrosis induced by asbestos (asbestosis), in part by generating reactive oxygen species (ROS) and promoting resistance to apoptosis. However, the mechanism(s) by which macrophages acquire apoptosis resistance is not known. Here, we confirm that macrophages isolated from asbestosis subjects are resistant to apoptosis and show they are associated with enhanced mitochondrial content of NADPH oxidase 4 (NOX4), which generates mitochondrial ROS generation. Similar results were seen in chrysotile-exposed WT mice, while macrophages from Nox4-/- mice showed increases apoptosis. NOX4 regulated apoptosis resistance by activating Akt1-mediated BAD phosphorylation. Demonstrating the importance of NOX4-mediated apoptosis resistance in fibrotic remodeling, mice harboring a conditional deletion of Nox4 in monocyte-derived macrophages exhibited increased apoptosis and were protected from pulmonary fibrosis. Moreover, resolution occurred when Nox4 was deleted in monocyte-derived macrophages in mice with established fibrosis. These observations suggest that NOX4 regulates apoptosis resistance in monocyte-derived macrophages and contributes to the pathogenesis of pulmonary fibrosis. Targeting NOX4-mediated apoptosis resistance in monocyte-derived macrophages may provide a novel therapeutic target to protect against the development and/or progression of pulmonary fibrosis.

Keywords: NOX4; apoptosis resistance; monocyte-derived macrophages; pulmonary fibrosis

DOI: https://doi.org/10.1016/j.jbc.2021.100810

Redox Biol. 2021 Jul;pii: S2213-2317(21)00171-3. [Epub ahead of print]43 102013

Regulation of TRPML1 channel activity and inflammatory exosome release by endogenously produced reactive oxygen species in mouse podocytes.

Guangbi Li, Dandan Huang, Ningjun Li, Joseph K Ritter, Pin-Lan Li.

The nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome in podocytes has been implicated in the initiation of glomerular inflammation during hyperhomocysteinemia (hHcy). However, the mechanism by which NLRP3 inflammasome products are released from podocytes remains unknown. The present study tested whether exosome secretion from podocytes is enhanced by NADPH oxidase-produced reactive oxygen species (ROS), which may serve as a pathogenic mechanism mediating the release of inflammatory cytokines produced by the NLRP3 inflammasome in podocytes after Hcy stimulation. We first demonstrated the remarkable elevation of endogenously produced ROS in podocytes treated with Hcy compared with control podocytes, which was abolished by pre-treatment with the NADPH oxidase inhibitors, gp91 ds-tat peptide and diphenyleneiodonium (DPI). In addition, Hcy induced activation in podocytes of NLRP3 inflammasomes and the formation of multivesicular bodies (MVBs) containing inflammatory cytokines, which were prevented by treatment with gp91 ds-tat or the ROS scavenger, catalase. Given the importance of the transient receptor potential mucolipin 1 (TRPML1) channel in Ca2+-dependent lysosome trafficking and consequent lysosome-MVB interaction, we tested whether lysosomal Ca2+ release through TRPML1 channels is inhibited by endogenously produced ROS in podocytes after Hcy stimulation. By GCaMP3 Ca2+ imaging, we confirmed the inhibition of TRPML1 channel activity by Hcy which was remarkably ameliorated by catalase and gp91 ds-tat peptide. By structured illumination microscopy (SIM) and nanoparticle tracking analysis (NTA), we found that ML-SA1, a TRPML1 channel agonist, significantly enhanced lysosome-MVB interaction and reduced exosome release in podocytes, which were attenuated by Hcy. Pre-treatment of podocytes with catalase or gp91 ds-tat peptide restored ML-SA1-induced changes in lysosome-MVB interaction and exosome secretion. Moreover, we found that hydrogen peroxide (H2O2) mimicked the effect of Hcy on TRPML1 channel activity, lysosome-MVB interaction, and exosome secretion in podocytes. Based on these results, we conclude that endogenously produced ROS importantly contributes to inflammatory exosome secretion from podocytes through inhibition of TRPML1 channel activity, which may contribute to the initiation of glomerular inflammation during hHcy.

Keywords: Exosome; Homocysteine; Lysosome; Podocyte; Reactive oxygen species; TRPML1 channel

DOI: https://doi.org/10.1016/j.redox.2021.102013

Front Cell Dev Biol. 2021 ;9 655794

NADPH Oxidase 5 and Melatonin: Involvement in Ram Sperm Capacitation.

Sara Miguel-Jiménez, Blanca Pina-Beltrán, Silvia Gimeno-Martos, Melissa Carvajal-Serna, Adriana Casao, Rosaura Pérez-Pe.

Reactive oxygen species (ROS) play an essential role in mammalian sperm capacitation. NADPH oxidase 5 (NOX5) has been described as the main source of ROS production in some mammalian spermatozoa, such as human and equine. On the other hand, melatonin can decrease cellular ROS levels and regulates NOX activity in somatic cells. Therefore, the objectives of this work were (1) to identify NOX5 in ram spermatozoa and analyze its possible changes during in vitro capacitation and (2) to investigate the effect of melatonin on NOX5 expression and localization and on superoxide levels in capacitated ram spermatozoa. Protein bands associated with NOX5 were detected by Western blot analysis. Likewise, indirect immunofluorescence (IIF) revealed six different immunotypes for NOX5, which varied throughout in vitro capacitation. Superoxide (O2 ⋅-), evaluated by DHE/Yo-Pro-1, rose after in vitro capacitation and in the presence of the calcium ionophore A23187 but decreased in the presence of the NOX inhibitor GKT136901. GKT also reduced the percentage of capacitated and acrosome-reacted spermatozoa that had increased during incubation in capacitating conditions. The presence of melatonin at micromolar concentrations avoided the increment in O2 ⋅- and the changes in NOX5 immunotypes provoked by capacitation. In conclusion, NOX5 is present in ram spermatozoa and the changes in its distribution, associated with sperm capacitation, can be prevented by melatonin. To this extent, it could imply that melatonin exerts its antioxidant role, at least in part, by modulating NOX5 activity during ram sperm capacitation.

Keywords: NADPH oxidase; NOX5; capacitation; melatonin; ram spermatozoa; reactive oxygen species

DOI: https://doi.org/10.3389/fcell.2021.655794

Kidney Res Clin Pract. 2021 May 21.

Fabry disease exacerbates renal interstitial fibrosis after unilateral ureteral obstruction via impaired autophagy and enhanced apoptosis.

Sungjin Chung, Mina Son, Yura Chae, Songhee Oh, Eun Sil Koh, Yong Kyun Kim, Seok Joon Shin, Cheol Whee Park, Sung-Chul Jung, Ho-Shik Kim.

Background: Fabry disease is a rare X-linked genetic lysosomal disorder caused by mutations in the GLA gene encoding alpha-galactosidase A. Despite some data showing that profibrotic and proinflammatory cytokines and oxidative stress could be involved in Fabry disease-related renal injury, the pathogenic link between metabolic derangement within cells and renal injury remains unclear.
Methods: Renal fibrosis was triggered by unilateral ureteral obstruction (UUO) in mice with Fabry disease to investigate the pathogenic mechanism leading to fibrosis in diseased kidneys.
Results: Compared to kidneys of wild-type mice, lamellar inclusion bodies were recognized in proximal tubules of mice with Fabry disease. Sirius red and trichrome staining revealed significantly increased fibrosis in all UUO kidneys, though it was more prominent in obstructed Fabry kidneys. Renal messenger RNA levels of inflammatory cytokines and profibrotic factors were increased in all UUO kidneys compared to sham-operated kidneys but were not significantly different between UUO control and UUO Fabry mice. Protein levels of Nox2, Nox4, NQO1, catalase, SOD1, SOD2, and Nrf2 were not significantly different between UUO control and UUO Fabry kidneys, while the protein contents of LC3-II and LC3-I and expression of Beclin1 were significantly decreased in UUO kidneys of Fabry disease mouse models compared with wild-type mice. Notably, TUNEL-positive cells were elevated in obstructed kidneys of Fabry disease mice compared to wild-type control and UUO mice.
Conclusion: These findings suggest that impaired autophagy and enhanced apoptosis are probable mechanisms involved in enhanced renal fibrosis under the stimulus of UUO in Fabry disease.

Keywords: Autophagy; Fabry disease; Fibrosis; alpha-Galactosidase

DOI: https://doi.org/10.23876/j.krcp.20.264

Exp Ther Med. 2021 Jul;22(1): 762

Role of bone morphogenic protein-4 in gestational diabetes mellitus-related hypertension.

Benshuo Cai, Juan Du.

Hyperglycaemia stimulates the synthesis and release of bone morphogenetic protein-4 (BMP-4) in vascular endothelial cells, which further induces peroxide production and inflammatory responses, leading to vascular endothelial dysfunction. However, the role of BMP-4 in gestational diabetes mellitus (GDM)-related vascular endothelial dysfunction remains unclear. In the present study, the hypothesis that the overexpression of BMP-4 would induce GDM-related hypertension by impairing vascular endothelial function was evaluated. An animal model of GDM was established in Sprague-Dawley (SD) rats. Based on blood pressure, rats were divided into control, GDM and GDM + hypertension (HT) groups. The expression levels of BMP-4, cyclooxygenase-2 (COX-2), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX-1) and vascular cell adhesion molecule 1 (VCAM-1) in the endothelium of the abdominal aorta of rats in each group were determined via immunohistochemistry and western blotting. Pregnant SD rats were divided into four groups, separately infused with BMP-4, BMP-4 + noggin, noggin or vehicle by osmotic pumps, and blood pressure and vasorelaxation were examined. Immunohistochemistry indicated that the expression levels of the four proteins were lower in the control group than in the GDM and GDM + HT groups. The positive expression rate of VCAM-1 was significantly lower in the control group than in the GDM and GDM+HT groups, and the differences were statistically significant (χ2=17.325, P<0.05; χ2=10.080, P<0.05). Western blotting revealed that the expression level of the COX-2 protein exhibited a sequential increase in the three groups. The expression level of COX-2 in the control and GDM groups was significantly lower than that in the GDM+HT group (3.358±1.286; P<0.05 and P<0.05, respectively). The expression level of VCAM-1 protein in the three groups also exhibited a significant sequential increase (F=31.732; P≤0.001). The expression level of VCAM-1 in the control and GDM groups was significantly lower than that in the GDM+HT group (2.698±0.223; P≤0.001 and P≤0.001, respectively). Infusion of BMP-4 increased systolic blood pressure (from 82 to 112 mmHg) and impaired vasorelaxation in pregnant SD rats after 2 weeks. Co-treatment with noggin completely blocked BMP-4-induced effects. Thus, the BMP-4/NOX-1/COX-2 signalling pathway may be involved in GDM-related hypertension, but VCAM-1 may be substantially associated with GDM-related hypertension. Furthermore, overexpression of BMP-4 could lead to hypertension by impairing endothelial function in pregnancy.

Keywords: bone morphogenetic protein-4; endothelial dysfunction; gestational diabetes mellitus; noggin

DOI: https://doi.org/10.3892/etm.2021.10194