NV14 from serine O‐acetyltransferase of cyanobacteria influences the antioxidant enzymes in vitro cells, gene expression against H₂O₂ and other responses in vivo zebrafish larval model

Abstract

In this study, we have identified a novel peptide NV14 with antioxidative functions from serine O‐acetyltransferase (SAT) of Artrospira platensis (Ap). The full sequence of ApSAT and its derived NV14 peptide “NVRIGAGSVVLRDV” (141–154) was characterized using bioinformatics tools. To address the transcriptional activity of ApSAT in response to induce generic oxidative stress, the spirulina culture was exposed to H2O2 (10 mM). The ApSAT expression was studied using RT‐PCR across various time points and it was found that the expression of the ApSAT was significantly upregulated on Day 15. The in vitro cytotoxicity assay against NV14 was performed in human dermal fibroblast cells and human blood leukocytes. Results showed that NV14 treatment was non‐cytotoxic to the cells. Besides, in vivo treatment of NV14 in zebrafish larvae did not exhibit the signs of developmental toxicity. Further, the in vitro antioxidant assays enhanced the activity of the antioxidant enzymes, such as SOD and CAT, due to NV14 treatment; and also significantly reduced the MDA levels, while increasing the superoxide radical and H2O2 scavenging activity. The expression of antioxidant enzyme genes glutathione peroxidase, γ‐glutamyl cysteine synthase, and glutathione S‐transferase were found to be upregulated in the NV14 peptide pretreated zebrafish larvae when induced with generic oxidative stress, H2O2. Overall, the study showed that NV14 peptide possessed potent antioxidant properties, which were demonstrated over both in vitro and in vivo assays. NV14 enhanced the expression of antioxidant enzyme genes at the molecular level, thereby modulating and reversing the cellular antioxidant balance disrupted due to the H2O2‐induced oxidative stress.

Embryonic exposure to butylparaben and propylparaben induced developmental toxicity and triggered anxiety‐like neurobehavioral response associated with oxidative stress and apoptosis in the head of zebrafish larvae

“…90 Among the antioxidant enzymes, SOD serves as the first line of defense in the antioxidant system, converting superoxide radicals to H 2 O 2 , while CAT catalyzes the conversion of H 2 O 2 to water. 44,91,92 The enzyme catalase plays an important role in preventing lipid peroxidation by protecting cells against oxidative stress. 93 Since the brain being a lipid rich organ with high energy consumption, it more prone to oxidative mediated cell injury.…”

“…All of these antioxidant enzymes are known to protect neurons against oxidative stress mediated injury 90 . Among the antioxidant enzymes, SOD serves as the first line of defense in the antioxidant system, converting superoxide radicals to H 2 O 2 , while CAT catalyzes the conversion of H 2 O 2 to water 44,91,92 . The enzyme catalase plays an important role in preventing lipid peroxidation by protecting cells against oxidative stress 93 .…”

“…The following non‐lethal malformations such as pericardial edema, bent spine, bent tail, yolk sac edema and blood cell accumulation were observed in 96 hpf zebrafish larvae. The malformation percentage was calculated for each deformity ( n = 40/group, three independent exposure groups) 44 …”

“…The malformation percentage was calculated for each deformity (n = 40/group, three independent exposure groups). 44…”

“…Diphenyl-1-pyrenylphosphine (DPPP), a fluorescent dye, was used for measuring the lipid peroxidation levels. 44,59 After the exposure experiments, 96 hpf larvae were transferred to a 24 well plate and treated with DPPP (25 μg/ml), further incubated for 1 h in the dark at 28.5 C.…”