The involvement of reactive oxygen species derived from NADPH oxidase-1 activation on the constitutive tyrosine auto-phosphorylation of RET proteins

Synthesis and Use of the Bifunctional Sulfenic Acid Probe BCN-E-BCN for In Vitro and Cell-Based Assays of Protein Oxidation

The reversible oxidation of cysteine thiol groups to sulfenic acid by reactive oxygen species (ROS) such as hydrogen peroxide can impact protein function, activity, and localization. As a consequence, ROS have profound effects on cell functions including proliferation, differentiation, and survival. Furthermore, there are clear associations between the effects of ROS on cells and the etiology of several diseases including cancer and neurodegeneration. In spite of the importance of cysteine sulfenylation as a validated post-translational modification, its labile nature impedes efficient and reproducible detection of proteins with cysteine sulfenic acid residues. To overcome this challenge, we developed a novel cell-permeable bifunctional reagent, consisting of two linked bicyclo[6.1.0]nonyne (BCN) moieties coupled with a short ethylenediamine-derived linker (BCN-E-BCN) that enables the detection of sulfenylated proteins in vitro and in intact cells. The two symmetrical BCN groups allow protein sulfenic acids to be selectively tagged with a BCN at one end while allowing for copper-free click chemistry with azide-tagged reagents of the opposite BCN. In this protocol, the synthesis of BCN-E-BCN and its use to detect cysteine sulfenic acids will be detailed. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Copper-mediated cyclopropanation of 1,5-cyclooctadiene Basic Protocol 2: Synthesis of endo- and exo-bicyclononyne Basic Protocol 3: Synthesis of endo-BCN-E-BCN Basic Protocol 4: BCN-E-BCN treatment of wild-type and cysteine-deficient mutant recombinant cofilin protein Basic Protocol 5: BCN-E-BCN labeling in live cells Basic Protocol 6: Western blotting and visualization of BCN-E-BCN-labeled samples.

Association analysis of NOX5 polymorphisms with Hirschsprung disease

BACKGROUND/PURPOSE

Hirschsprung disease (HSCR) is a developmental disease characterized by the absence of ganglion cells in the intestinal region. NADPH oxidase5 (NOX5) has been identified as one of the possible candidate genes for risk of Hirschsprung disease in our recent genome wide association study (GWAS). In this study, we performed a replication study to analyze the association of NOX5 polymorphisms with HSCR risk and conducted an extended analysis to investigate further associations for sub-groups and haplotypes.

METHODS

A total of 23 NOX5 single nucleotide polymorphisms (SNPs) were genotyped in 187 HSCR patients and 283 unaffected controls. Statistical analysis was performed to examine the effects of genotype on risk of HSCR and HSCR subtype.

RESULTS

Logistic regression analyses revealed that six SNPs (rs59355559, rs62010828, rs34990910, rs11856030, rs311905, and rs8024894) were associated with risk of HSCR (minimum p = 0.007 at rs62010828). Moreover, three SNPs (rs59355559, rs62010828, and rs8024894) were significantly associated with risk of long-segment HSCR (L-HSCR) subtype and 5 SNPs (rs59355559, rs62010828, rs34990910, rs11856030, and rs8024894) were found to be associated with risk of TCA subtype.

CONCLUSION

Our results demonstrate that genetic variants in NOX5 have genetic effects on risk of HSCR, which may serve as useful preliminary information for further study.

LEVELS OF EVIDENCE

Level III of prognosis study.

Interventions and mechanisms of N-acetylcysteine on monocrotaline-induced pulmonary arterial hypertension

The aim of the present study was to investigate the impact of N-acetylcysteine (NAC) on the expression of activin receptor-like kinase-1 (ALK-1) and mothers against decapentaplegic homolog 1 (Smad1) in the pulmonary artery of rats with pulmonary arterial hypertension (PAH), and to explore the possible mechanisms underlying its effects on pulmonary vascular remodeling (PVR). In total, 32 Wistar rats were randomly divided into four groups: Control, model, low-dose (100 mg/kg/day) NAC and high-dose (500 mg/kg/day) NAC. Monocrotaline (MCT) was intraperitoneally injected to prepare the model, and the right ventricular hypertrophy index (RVHI) and hemodynamic parameters were detected 6 weeks later. Hematoxylin and eosin staining was used to observe the pulmonary arterial structural changes and evaluate the peri-pulmonary artery inflammation score. Additionally, western blot analysis was used to detect the protein expression of ALK-1 and Smad1 in the pulmonary artery. The results demonstrated that treatment with NAC reduced RVHI and mean pulmonary artery pressure. In addition, NAC reduced the MCT-induced PVR, pulmonary inflammation score and upregulation of ALK-1 and Smad1. These results indicate that ALK-1 and Smad1 participate in the formation of PAH and the process of PVR, and suggest that NAC may inhibit PAH by inhibiting the expression of ALK-1 and Smad1 in the pulmonary artery.

Mechanisms of N‑acetylcysteine in reducing monocrotaline‑induced pulmonary hypertension in rats: Inhibiting the expression of Nox1 in pulmonary vascular smooth muscle cells

The aim of the present study was to investigate the impact of N‑acetylcysteine (NAC) on the expression of reduced nicotinamide adenine dinucleotide phosphate oxidase 1 (Nox1), and the proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) in rats exhibiting monocrotaline (MCT)‑induced pulmonary hypertension, and to investigate the possible mechanisms and treatment roles of NAC in pulmonary vascular remodeling (PVR). A total of 18 Wistar rats were randomly divided into three groups: The control (C) group; the MCT (M) group; and the NAC (N) group. The right ventricular hypertrophy index (RVHI) and other indicators were recorded 6 weeks subsequently. Groups C and M were divided into two subgroups: Groups C1 and M1 (control); and group C2 and M2 group (treated with ML171). Group N was not sub‑divided. PASMCs were isolated, and the vascular remodeling and Nox1 positioning were observed. The expression of Nox mRNA in each group, and the proliferation, apoptosis, and superoxide dismutase (SOD) activity of PASMCs, prior to and following the ML171 treatment, were measured. NAC was able to decrease RVHI and other indicators (P<0.001). The mRNA expression of Nox1 and Nox4 in group M was significantly increased compared with group C (P<0.05), and NAC was able to significantly decrease the expression of these two factors in lung tissue (P<0.001). MCT‑PASMCs exhibited differences in Nox1 mRNA expression (P<0.001), and the total SOD activity was Nox1‑dependently increased (r=0.949; P<0.001). NAC was able to decrease Nox1‑derived reactive oxygen species in PASMCs, thereby improving PVR. Nox1 was able to increase SOD activity, thereby demonstrating its positive effect on the proliferation of MCT‑PASMCs.