bims-noxint 2020-05-03 papers

Issue of 2020–05–03
five papers selected by
Laia Caja Puigsubira, Uppsala University

Clin Transl Sci. 2020 May 01.

microRNA-100 Enhances Autophagy and Suppresses Migration and Invasion of Renal Cell Carcinoma Cells via Disruption of NOX4-dependent mTOR Pathway.

Xiumin Liu, Lili Zhong, Ping Li, Peng Zhao.

Renal cell carcinoma (RCC) is the most common kidney malignancy and has a poor prognosis owing to its resistance to chemotherapy. Recently, microRNAs (miRNAs or miRs) have been shown to have a role in cancer metastasis and potential as prognostic biomarkers in cancer. In the present study, we aim to explore the potential role of miR-100 in RCC by targeting NADPH oxidase 4 (NOX4) through the mammalian target of rapamycin (mTOR) pathway. Initially, microarray-based gene expression profiling of RCC was employed to identify differentially expressed genes. Next, the expression of miR-100 and NOX4 was examined in RCC tissues and cell lines. Then, the interaction between miR-100 and NOX4 was identified using bioinformatics analysis and dual-luciferase reporter assay. Gain- or loss-of-function approaches were adopted to manipulate miR-100 and NOX4 in order to explore the functional roles in RCC. The results revealed the presence of an upregulated NOX4 and a downregulated miR-100 in both RCC tissues and cell lines. NOX4 was verified as a target of miR-100 in cells. In addition, overexpression of miR-100 or NOX4 silencing could increase autophagy while decreasing the expression of mTOR pathway-related genes and migration and invasion. Conjointly, upregulated miR-100 can potentially increase the autophagy and inhibit the invasion and migration of RCC cells by targeting NOX4 and inactivating the mTOR pathway, which contributes to an extensive understanding of RCC and may provide novel therapeutic options for this disease.

Keywords: Autophagy; Invasion; Migration; NOX4; Renal cell carcinoma; mTOR pathway; microRNA-100

DOI: https://doi.org/10.1111/cts.12798

J Cell Mol Med. 2020 Apr 29.

Diabetes aggravates myocardial ischaemia reperfusion injury via activating Nox2-related programmed cell death in an AMPK-dependent manner.

Chunyan Wang, Lijie Zhu, Wenlin Yuan, Lingbin Sun, Zhengyuan Xia, Zhongjun Zhang, Weifeng Yao.

Cardiovascular diseases such as myocardial ischaemia have a high fatality rate in patients with diabetes. This study was designed to expose the crosstalk between oxidative stress and AMPK, a vital molecule that controls biological energy metabolism, in myocardial ischaemia reperfusion injury (I/RI) in diabetic rats. Diabetes was stimulated in rats using streptozotocin injection. Rats were separated on random into control, control + I/R, Diabetes, Diabetes + I/R, Diabetes + I/R + N-acetylcysteine and Diabetes + I/R + Vas2870 groups. Myocardial infarct size was determined, and the predominant Nox family isoforms were analysed. In vitro, the H9C2 cells were administered excess glucose and exposed to hypoxia/reoxygenation to mimic diabetes and I/R. The AMPK siRNA or AICAR was used to inhibit or activate AMPK expression in H9C2 cells, respectively. Then, myocardial oxidative stress and programmed cell death were measured. Diabetes or high glucose levels were found to aggravate myocardial I/RI or hypoxia/reoxygenation in H9C2 cells, as demonstrated by an increase in myocardial infarct size or lactate dehydrogenase levels, oxidative stress generation and induction of programmed cell death. In diabetic rat hearts, cardiac Nox1, Nox2 and Nox4 were all heightened. The suppression of Nox2 expression using Vas2870 or Nox2-siRNA treatment in vivo or in vitro, respectively, protected diabetic rats from myocardial I/RI. AMPK gene knockout increased Nox2 protein expression while AMPK agonist decreased Nox2 expression. Therefore, diabetes aggravates myocardial I/RI by generating of Nox2-associated oxidative stress in an AMPK-dependent manner, which led to the induction of programmed cell death such as apoptosis, pyroptosis and ferroptosis.

Keywords: AMPK; Nox2; diabetes; myocardial ischaemia reperfusion injury; programmed cell death

DOI: https://doi.org/10.1111/jcmm.15318

Redox Rep. 2020 Dec;25(1): 41-50

Evidence for NADPH oxidase activation by GPR40 in pancreatic β-cells.

Gabriela Nunes Marsiglio-Librais, Eloisa Aparecida Vilas-Boas, Christopher Carlein, Markus Daniel Alexander Hoffmann, Leticia Prates Roma, Angelo Rafael Carpinelli.

Objective: Investigate the involvement of the fatty acids receptor GPR40 in the assembly and activation of NADPH oxidase and the implications on pancreatic β-cell function.Methods: BRIN-BD11 β-cells were exposed to GPR40 agonist (GW9508) or linoleic acid in different glucose concentrations. Superoxide and H2O2 were analyzed, respectively, by DHE fluorescence and by fluorescence of the H2O2 sensor, roGFP2-Orp1. Protein contents of p47phox in plasma membrane and cytosol were analyzed by western blot. NADPH oxidase role was evaluated by p22phox siRNA or by pharmacological inhibition with VAS2870. NOX2 KO islets were used to measure total cytosolic calcium and insulin secretion.Results: GW9508 and linoleic acid increased superoxide and H2O2 contents at 5.6 and 8.3 mM of glucose. In addition, in 5.6 mM, but not at 16.7 mM of glucose, activation of GPR40 led to the translocation of p47phox to the plasma membrane. Knockdown of p22phox abolished the increase in superoxide after GW9508 and linoleic acid. No differences in insulin secretion were found between wild type and NOX2 KO islets treated with GW9508 or linoleic acid.Discussion: We report for the first time that acute activation of GPR40 leads to NADPH oxidase activation in pancreatic β-cells, without impact on insulin secretion.

Keywords: BRIN-BD11; GPR40; GW9508; Insulin secretion; Linoleic acid; NADPH oxidase; NOX2 KO islets; ROS; p47phox translocation; roGFP2-Orp1

DOI: https://doi.org/10.1080/13510002.2020.1757877

Biophys Chem. 2020 Apr 14. pii: S0301-4622(20)30087-9. [Epub ahead of print]262 106379

Binding of Nox5's EF-Hand domain to the peptides corresponding to the phosphorylatable region and regulatory inhibitory loop in its dehydrogenase domain.

Chin-Chuan Wei, Evan Hay, Dustin Smith, Laura Lloyd, Ganesh Acharya, Rebecca Ngo.

Reactive oxygen species (ROS) produced by NADPH oxidase 5 (Nox5) are regulated by Ca2+ flux through the interactions of its self-contained EF-hand domain (EFD), dehydrogenase domain (DH), and transmembrane domain. Studies suggest that the regulatory EF-hand binding domain (REFBD) and phosphorylatable (PhosR) sequences within DH play an important role in Nox5's superoxide-generating activity. However, the interplay of the EFD-DH interaction is largely unclear. Here, we used two synthetic peptides corresponding to the putative REFBD and PhosR sequences, as well as DH construct proteins, and separately studied their binding to EFD by fluorescence spectroscopy and calorimetry. With mutagenesis, we revealed that the C-terminal half domain of EFD binds specifically to REFBD in a Ca2+-dependent manner, which is driven primarily by hydrophobic interactions to form a more compact structure. On the other hand, the interaction between EFD and PhosR is not Ca2+-dependent and is primarily dominated by electrostatic interactions. The binding constants (Ka) for both peptides to EFD were calculated to be in the range of 105 M-1. The formation of the binary complex EFD/REFBD and ternary complex EFD/REFBD/PhosR was demonstrated by fluorescence resonance energy transfer (FRET). However, EFD binding to PhosR appears to be not biologically important while the conformational change on its C-terminal half domain resembles a major factor in EFD-DH domain-domain interactions.

Keywords: Calcium binding; Calorimetry; Domain-domain interactions; EF-hand; Fluorescence; NADPH oxidase 5

DOI: https://doi.org/10.1016/j.bpc.2020.106379

Am J Nephrol. 2020 Apr 29. 1-11

Glomerular Transcriptome Profiles in Focal Glomerulosclerosis: New Genes and Pathways for Steroid Resistance.

Jun Tong, Yuanmeng Jin, Qinjie Weng, Shuwen Yu, Hafiz Muhammad Jafar Hussain, Hong Ren, Jing Xu, Wen Zhang, Xiao Li, Weiming Wang, Jingyuan Xie, Nan Chen.

BACKGROUND: Patients with focal segmental glomerulosclerosis (FSGS) characterized by steroid-resistant nephrotic syndrome (SRNS) are prone to progress to ESRD. Mechanism for the FSGS patients' response to steroid treatment is still unknown and currently, it is impossible to predict the steroid resistance before treatment of patients with FSGS.
METHODS: To identify biomarkers and potential therapeutic targets of FSGS patients with SRNS, patients diagnosed as kidney biopsy-proven FSGS and nephrotic syndrome (NS) were prospectively enrolled. They were divided into 2 groups, steroid-sensitive NS and SRNS based on their treatment response. Cortical regions were selected from biopsied renal tissues, and glomeruli were isolated under an inverted microscope. RNA was prepared from the isolated glomeruli and further used for microarray analysis. Followed by multiple analyses, the top 6 highest and lowest, and a selected panel of differentially expressed genes obtained and their related pathways were validated via real-time PCR, western blot, and measurement of reactive oxygen species (ROS).
RESULTS: In SRNS group, we discovered that the most significant up-regulated pathway was primarily related to cellular amino acid and derivative metabolic process. Meanwhile, the most significant down-regulated pathway was primarily involved in anatomical structure morphogenesis. Moreover, we found NADPH oxidase 4 (NOX4), one of the key regulators of renal ROS, at a much higher level in SRNS both at transcriptomic and proteomic levels. We also found the levels of ROS, p-p38 MAPK and matrix metalloproteinase (MMP)-2, which were all regulated by NOX4, were also higher in glomeruli isolated from SRNS patients. At last, we detected stimulated by retinoic acid gene 6 homolog (STRA6), a cell surface receptor formerly known as a gene preventing podocytes from over-proliferative lesion induced by HIV infection and was up-regulated by retinoic acid, expressed at a much higher level in SRNS kidneys.
CONCLUSION: We found 2 potential mechanisms underline the SRNS, NOX4/ROS/P38 MAPK/MMP-2 pathway and STRA6. Our findings provided new insights into the steroid resistance.

Keywords: Focal segmental glomerulosclerosis; Pharmacological target; Reactive oxygen species; Steroid-resistant nephrotic syndrome; Stimulated by retinoic acid gene 6 homolog

DOI: https://doi.org/10.1159/000505956