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Cited by 30Skin Protection and Agingmelanin and skin pigmentationProtein Hydrolysis and Bioactive Peptides

A Frog Peptide Ameliorates Skin Photoaging Through Scavenging Reactive Oxygen Species

Open access
Feng, Guizhu, Wei, Lin, Che, Helong, Shen, Yan, Yang, Jun, Mi, Kai, Liu, Jin, Wu, Jing +2 more·2022·Frontiers in Pharmacology
DOI 10.3389/fphar.2021.761011PMC PMC8807480
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Abstract

Although many bioactive peptides have been identified from the frog skins, their protective effects and the molecular mechanisms against skin photodamage are still poorly understood. In this study, a novel 20-residue peptide (antioxidin-NV, GWANTLKNVAGGLCKMTGAA) was characterized from the skin of plateau frog Nanorana ventripunctata . Antioxidin-NV obviously decreased skin erythema, thickness and wrinkle formation induced by Ultraviolet (UV) B exposure in hairless mice. In UVB-irradiated keratinocytes (HaCaT cells) and hairless mice, it effectively inhibited DNA damage through reducing p-Histone H2A.X (γH2AX) expression, alleviated cell apoptosis by decreasing the expression of apoptosis-specific protein (cleaved caspase 3), and reduced interleukin-6 (IL-6) production via blocking UVB-activated Toll-like receptor 4 (TLR4)/p38/JNK/NF-κB signaling. In UVB-irradiated human skin fibroblasts (HSF cells) and hairless mice, it effectively restored HSF cells survival rate, and rescued α-SMA accumulation and collagen (especially type I collagen) production by restoring transforming growth factor-β1 (TGF-β1)/Smad2 signaling. We found that antioxidin-NV directly and rapidly scavenged intracellular and mitochondrial ROS in HaCaT cells upon UVB irradiation, and quickly eliminated the artificial free radicals, 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS + ). Taken together, antioxidin-NV directly and rapidly scavenged excessive ROS upon UVB irradiation, subsequently alleviated UVB-induced DNA damage, cell apoptosis, and inflammatory response, thus protecting against UVB-induced skin photoaging. These properties makes antioxidin-NV an excellent candidate for the development of novel anti-photoaging agent.

AI snapshot

Written from the paper’s full text.

TL;DR

Antioxidin-NV, a novel 20-residue frog-skin peptide from *Nanorana ventripunctata*, directly scavenges ROS and protects against UVB-induced skin photoaging in cells and hairless mice. It reduces DNA damage, apoptosis, inflammation, and restores collagen production via TGF-β1/Smad2 signaling.

Key findings

  • Antioxidin-NV (GWANTLKNVAGGLCKMTGAA) was isolated and characterized; MALDI-TOF MS measured 1963.70 Da versus calculated 1963.30 Da, and its precursor is 72 amino acids with a 24-residue signal peptide, 28-residue acidic region, and 20-residue mature peptide.
  • It rapidly scavenged ABTS+ in a dose- and time-dependent manner: at 80 μg/ml, 96% within 1 min and nearly 99% within 8 min; at 5 μg/ml, 40% within 4 min.
  • In UVB-irradiated HaCaT cells, apoptosis was 43.26% with UVB alone and 14.44% with antioxidin-NV at 40 μg/ml; it also reduced γH2AX, cleaved caspase 3, and IL-6 via blocking TLR4/p38/JNK/NF-κB signaling.
  • In UVB-irradiated hairless mice, topical antioxidin-NV reduced erythema, epidermal thickness, and wrinkle formation, restored α-SMA and type I collagen, and increased TGF-β1/Smad2 signaling; scrambled sNV had no significant therapeutic effect.

Methods

  • Peptide purification and characterization: skin secretions from *N. ventripunctata* (n = 30; 20–25 g) were fractionated by Sephadex G-50 and C18 RP-HPLC, then analyzed by Edman degradation, MALDI-TOF MS, and cDNA cloning; antioxidin-NV and scrambled sNV were synthesized.
  • In vitro assays: HaCaT keratinocytes and HSF cells were UVB-irradiated at 80 mJ/cm² and treated with antioxidin-NV (10, 20, 40 μg/ml) or vitamin C (40 μg/ml); outcomes included ABTS+ scavenging, intracellular/mitochondrial ROS, MTT cytotoxicity, hemolysis, DNA fragmentation, western blot, immunofluorescence, flow cytometry, and ELISA.
  • In vivo model: male SKH-1 hairless mice (n = 30, 6–8 weeks old, 20–30 g) were randomized into five groups of six; UVB was 100 mJ/cm² five times in week 1 then 200 mJ/cm² three times/week for 12 weeks, with topical 100 μl of 200 μg/ml antioxidin-NV, vitamin C, PBS, or sNV; skin was analyzed by H&E, Masson stain, IHC, immunofluorescence, western blot, and ELISA, with statistics by Student’s t-test or one-way ANOVA (p < 0.05).

Limitations

  • The paper states that the effects of antioxidin-NV on DNA damage-related signaling pathways need further investigation to clarify its protective mechanism in vitro and in vivo.
  • The paper reports no adverse effects on body weight, general health, or behavior with topical antioxidin-NV, but does not present a dedicated long-term toxicity or safety study.
  • Evident from the text: the in vivo work uses only male SKH-1 hairless mice, a single topical mouse dose (200 μg/ml), and no human data; in vitro experiments report n = 3 and in vivo n = 6, limiting broader generalization.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3389/fphar.2021.761011

Cites

46 of 47 references verified1 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 31 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Antioxidin-NV decreased skin erythema, thickness and wrinkle formation induced by UVB exposure in hairless mice.

    “Antioxidin-NV obviously decreased skin erythema, thickness and wrinkle formation induced by Ultraviolet (UV) B exposure in hairless mice.”
    • Also stated in: § Antioxidin-NV Suppressed UVB-Induced Skin Photoaging in Hairless Mice · boosted
      “topical application of antioxidin-NV significantly suppressed UVB-induced skin photoaging in hairless mice with reduced skin erythema, hyperplasia, wrinkling, and roughness compared to PBS-treated mice.”
    Quote in the paperSubstantial claim
  • Findingown data

    In UVB-irradiated HSF cells and hairless mice, antioxidin-NV rescued α-SMA accumulation and collagen (especially type I collagen) production by restoring TGF-β1/Smad2 signaling.

    “rescued α-SMA accumulation and collagen (especially type I collagen) production by restoring transforming growth factor-β1 (TGF-β1)/Smad2 signaling.”
    Quote in the paperSubstantial claim
  • Findingown data

    In UVB-irradiated HaCaT cells and hairless mice, antioxidin-NV inhibited DNA damage through reducing γH2AX expression.

    “In UVB-irradiated keratinocytes (HaCaT cells) and hairless mice, it effectively inhibited DNA damage through reducing p-Histone H2A.X (γH2AX) expression”
    • Also stated in: § Antioxidin-NV Inhibited UVB-Induced DNA Damage in HaCaT Cells and Hairless Mice by Reducing p-Histone H2A.X (γH2AX) Expression · plain
      “However, antioxidin-NV significantly reduced γH2AX expression in HaCaT cells induced by UVB irradiation in a dose-dependent manner (Figures 4B,C).”
    Quote in the paperSubstantial claim
  • Findingown data

    A novel 20-residue peptide (antioxidin-NV, GWANTLKNVAGGLCKMTGAA) was characterized from the skin of the plateau frog Nanorana ventripunctata.

    “In this study, a novel 20-residue peptide (antioxidin-NV, GWANTLKNVAGGLCKMTGAA) was characterized from the skin of plateau frog Nanorana ventripunctata.”
    • Also stated in: § Isolation and Characterization of Antioxidin-NV · plain
      “The purified peptide was designated as antioxidin-NV (Supplementary Figure S1C).”
    Quote in the paperSubstantial claim
  • Findingown data

    In UVB-irradiated HaCaT cells and hairless mice, antioxidin-NV alleviated cell apoptosis by decreasing cleaved caspase 3 expression.

    “alleviated cell apoptosis by decreasing the expression of apoptosis-specific protein (cleaved caspase 3)”
    • Also stated in: § Antioxidin-NV Inhibited UVB-Induced Cell Apoptosis in HaCaT Cells and Hairless Mice · plain
      “Immunofluorescence and western blot analysis showed that antioxidin-NV significantly reduced the expression of apoptotic protein cleaved caspase 3 (a marker protein for apoptosis) in the UVB-irradiated HaCaT cells in a dose-dependent manner (Figures 5B,C).”
    Quote in the paperSubstantial claim
  • May combine two claims. 23
  • Classified as probably not a substantial claim. 12
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingown data

    Antioxidin-NV did not exhibit cytotoxicity and hemolytic activity at an absolutely high concentration.

    “Besides, antioxidin-NV did not exhibit cytotoxicity and hemolytic activity at an absolutely high concentration (Supplementary Figure S3)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The antioxidin-NV precursor is composed of 72 amino acid residues, including a predicted signal peptide (24 amino acid residue), an acidic peptide region (28 amino acid residue) that ends in a typical trypsin-like proteases processing site (-Lys51Arg52-), followed by a mature peptide (20 amino acid).

    “It is composed of 72 amino acid residues, including a predicted signal peptide (24 amino acid residue), an acidic peptide region (28 amino acid residue) that ends in a typical trypsin-like proteases processing site (-Lys51Arg52-), followed by a mature peptide (20 amino acid).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    UVB induced fragmentation of DNA in HaCaT cells and accumulation of γH2AX signals in the cells and in vivo.

    “We observed that UVB induced fragmentation of DNA in HaCaT cells and accumulation of γH2AX signals in the cells and in vivo”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Antioxidin-NV ameliorated UVB-induced apoptosis and inhibited the expression of apoptosis-specific protein cleaved caspase 3 in HaCaT cells and skin tissues.

    “antioxidin-NV ameliorated UVB-induced apoptosis and inhibited the expression of apoptosis-specific protein, cleaved caspase 3 in HaCaT cells and skin tissues”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    MALDI-TOF MS analysis indicated that antioxidin-NV had a measured molecular mass of 1963.70 Da, matching well with the calculated molecular mass of 1963.30 Da.

    “MALDI-TOF MS analysis indicated that antioxidin-NV had a measured molecular mass of 1963.70 Da (Supplementary Figure S2), matching well with the calculated molecular mass of 1963.30 Da.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    At the concentration of 80 μg/ml, antioxidin-NV scavenged 96% ABTS+ within 1 min, and scavenged nearly 99% ABTS+ within 8 min.

    “At the concentration of 80 μg/ml, antioxidin-NV scavenged 96% ABTS+ within 1 min, and scavenged nearly 99% ABTS+ within 8 min.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    No adverse effect on the body weight, general health or behavior of the mice were observed for the topical antioxidin-NV treatment.

    “no adverse effect on the body weight, general health or behavior of the mice were observed for the topical antioxidin-NV treatment”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    UVB-irradiation resulted in a reduction of the thickness of epidermal layers, but topical application of antioxidin-NV significantly reversed this reduction.

    “H&E staining of the dorsal skin showed that UVB-irradiation resulted in a reduction of the thickness of epidermal layers, but topical application of antioxidin-NV significantly reversed this reduction (Figures 3B,C).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The skin secretions of N. ventripunctata were divided into five fractions after Sephadex G-50 gel filtration.

    “As shown in Supplementary Figure S1A, the skin secretions of N. ventripunctata were divided into five fractions after Sephadex G-50 gel filtration.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    Antioxidin-NV inhibits UVB-induced DNA damage, apoptosis, and inflammation.

    “As subsequent results, it inhibits UVB-induced DNA damage, apoptosis, and inflammation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    UV irradiation, especially UVB, triggers overproduction of ROS, leading to photo-induced skin damage, skin diseases and even skin cancer.

    “UV irradiation, especially UVB, has the twofold effect of regulating the brain and central neuroendocrine system to rebalance the internal environment (Slominski et al., 2018), and triggering the overproduction of ROS, leading to photo-induced skin damage, skin diseases and even skin cancer (Rinnerthaler et al., 2015).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Slominski et al., 2018 source

      Not checked in the free run.

    • cites Rinnerthaler et al., 2015 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The two frog-skin AOPs antioxidin-RL and OA-VI12 prevented UVB irradiation-induced photoaging in mice, but their detailed mechanisms remain to be fully understood.

    “They prevented UVB irradiation-induced photoaging in mice, but the detailed mechanisms of the two AOPs remain to be fully understood.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Qin et al., 2018 source

      Not checked in the free run.

    • cites Yin et al., 2019 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Frog-skin antioxidant peptides (AOPs) possess gene-encoded origins like antioxidant enzymes but show no enzyme activity, and instead function as direct free radical scavengers like low molecular weight antioxidants (LMWAs).

    “They possess gene-encoded origins as antioxidant enzymes do, but they show no enzyme activity. Instead they function as direct free radical scavengers like LMWAs.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Yang et al., 2009 source

      Not checked in the free run.

    • cites Liu et al., 2010 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    Antioxidin-NV directly and rapidly scavenged excessive ROS upon UVB irradiation, subsequently alleviated UVB-induced DNA damage, cell apoptosis, and inflammatory response, thus protecting against UVB-induced skin photoaging.

    “Taken together, antioxidin-NV directly and rapidly scavenged excessive ROS upon UVB irradiation, subsequently alleviated UVB-induced DNA damage, cell apoptosis, and inflammatory response, thus protecting against UVB-induced skin photoaging.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Currently, only two frog-skin AOPs with potential skin protective effects in vivo have been described.

    “Currently, only two frog-skin AOPs with potential skin protective effects in vivo have been described (Qin et al., 2018; Yin et al., 2019).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Qin et al., 2018 source

      Not checked in the free run.

    • cites Yin et al., 2019 source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    The overproduction and/or mismanagement of ROS may result in oxidative stress, which has been implicated in a large variety of skin disorders and skin diseases, such as UV irradiation damages, skin inflammation, bacterial skin infections, and skin cancer.

    “The overproduction and/or mismanagement of ROS may result in oxidative stress, which have been implicated in a large variety of skin disorders and skin diseases, such as UV irradiation damages, skin inflammation, bacterial skin infections, and skin cancer (Portugal et al., 2007; Pham-Huy et al., 2008; Godic et al., 2014).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Portugal et al., 2007 source

      Not checked in the free run.

    • cites Pham-Huy et al., 2008 source

      Not checked in the free run.

    • cites Godic et al., 2014 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Results are shown as mean ± SD from three independent experiments.

    “Results are shown as mean ± SD from three independent experiments.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The data indicate that antioxidin-NV had a strong ability to scavenge ROS induced by UVB irradiation, suggesting a strong antioxidant activity of antioxidin-NV.

    “The data indicate that antioxidin-NV had a strong ability to scavenge ROS induced by UVB irradiation, suggesting a strong antioxidant activity of antioxidin-NV.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    HSFs can synthesize and maintain the extracellular matrix of skin and reduce skin photoaging.

    “HSFs, which can synthesize and maintain the extracellular matrix of skin and reduce skin photoaging, are a very critical cell type in skin photoaging (Tobin, 2017).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Tobin, 2017 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Collagen is derived from HSF cells and plays an important role in maintaining the elasticity of skin.

    “Collagen is derived from HSF cells and plays important role in maintaining the elasticity of skin (Lee et al., 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Lee et al., 2012 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Type I collagen is the major component of collagen fibrils and the most abundant structural protein in the skin.

    “Type I collagen, which is the major component of collagen fibrils, is the most abundant structural protein in the skin (Makrantonaki and Zouboulis, 2007).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Makrantonaki and Zouboulis, 2007

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    To cope with the increasing oxidative stress, N. ventripunctata should possess potent free radical scavenging and radio-protective effect for their survival.

    “To cope with the increasing oxidative stress, N. ventripunctata should possess potent free radical scavenging and radio-protective effect for their survival.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: N. ventripunctata lives in high altitude (3120–4100 m) where there is low temperature, long sunshine duration and strong ultraviolet radiation.

  • Classified as probably not a substantial claim.

    Premisecitation

    MAPKs and NF-κB signaling are important signal transduction pathways activated by UVB irradiation.

    “MAPKs and NF-κB signaling are known to be important signal transduction pathways activated by UVB irradiation (Subedi et al., 2017).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Subedi et al., 2017 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The TGF-β/Smad pathway promotes the differentiation of myofibroblasts.

    “the TGF-β/Smad pathway also promotes the differentiation of myofibroblasts (Guo et al., 2009).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Guo et al., 2009 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    α-SMA is a marker of myofibroblast which has a higher capacity to synthesize collagen.

    “a-SMA is also a marker of myofibroblast which has a higher capacity to synthesize collagen (Nakyai et al., 2018).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Nakyai et al., 2018 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Inflammation enhances the epidermal hyperproliferative response to UVB and plays a crucial role in promoting skin photoaging.

    “Inflammation was found to enhance the epidermal hyperproliferative response to UVB and play a crucial role in promoting skin photoaging (Pillai et al., 2005).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Pillai et al., 2005 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Study design and conductnone given

    Histological and immunohistochemical slides were read in blindness.

    “The pathology slides were read in blindness, and the images were recorded.”
    • Also stated in: § Masson Stain · plain
      “Finally, the slides were read in blindness, and the images were recorded.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The mice were randomized into five treatment groups (six mice per group).

    “The mice were randomized into five treatment groups (six mice per group)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Antioxidin-NV identified from N. ventripunctata skin is a bioactive/effector compound with potential anti-photoaging ability.

    “antioxidin-NV identified from N. ventripunctata skin is a bioactive/effector compound with potential anti-photoaging ability”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Series of peptides have been identified with antioxidant activity from the skin of frogs lived in this plateau area.

    “series of peptides have been identified with antioxidant activity from the skin of frogs lived in this plateau area (Yang et al., 2009; Liu et al., 2010)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Yang et al., 2009 source

      Not checked in the free run.

    • cites Liu et al., 2010 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    These pathways may orchestrate in regulating cytokine expression and inhibiting skin photoaging process.

    “they may orchestrate in regulating these cytokines expression and inhibiting skin photoaging process”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Antioxidin-NV-mediated reduction of free radical accumulation led to the reduction of DNA damage, apoptosis, and inflammation upon UVB radiation, thereby providing protection against UVB-induced skin photoaging.

    “antioxidin-NV-mediated reduction of free radical accumulation led to the reduction of DNA damage, apoptosis, and inflammation upon UVB radiation, thereby providing protection against UVB-induced skin pohto-aging”
    Quote in the paperSubstantial claim
32 of 32

  • The paper relies on this without support.

    N. ventripunctata lives in high altitude (3120–4100 m) where there is low temperature, long sunshine duration and strong ultraviolet radiation.

    “N. ventripunctata lives in high altitude (3120–4100 m) where there is low temperature, long sunshine duration and strong ultraviolet radiation.”

  • The paper relies on this without support.

    Smad proteins, including Smad2, are essential components of downstream TGF-β signaling.

    “Smad proteins, including Smad2, are essential components of downstream TGF-β signaling.”
    “Smad proteins, including Smad2, are key regulators in TGF-β signaling pathways and they are essential components of downstream TGF-β signaling.”

  • The paper relies on this without support.

    The southwestern plateau area of China possesses long duration of sunshine and strong ultraviolet radiation.

    “This plateau area possesses long duration of sunshine, and suffers strong ultraviolet radiation”

  • The paper relies on this without support.

    The naked skin of frogs in the southwestern plateau area of China evolved an effective antioxidant system to scavenge free radicals induced by light radiation.

    “which make the naked skin of frogs evolve an effective antioxidant system to scavenge free radicals induced by light radiation”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • A cathelicidin molecule from the spot-bellied plateau frog Nanorana ventripunctata has been shown to reduce the effects of ultraviolet B on skin photoaging in mice by ROS scavenging.

    “Recently, a cathelicidin molecule (ARGKKECKDDRCRLLMKRGSFSYV) from the spot-bellied plateau frog Nanorana ventripunctata has been shown to reduce the effects of ultraviolet B (UVB) on skin photoaging in mice by ROS scavenging [189].”

    From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [189]

  • Antimicrobial peptides are involved in the regulation of oxidative-antioxidant homeostasis.

    “This could lead to the notion that antimicrobial peptides are involved in the regulation of oxidative-antioxidant homeostasis.”

    From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [189]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Opposite effects reported for epidermal thickness

    Major

    The Results say UVB reduced epidermal thickness and antioxidin-NV reversed that reduction. The Figure 3 caption instead says antioxidin-NV decreased UVB-induced thickness, reversing the direction of a reported treatment effect.

  • Conflicting DCFH-DA concentrations

    Major

    The method specifies 30 μM DCFH-DA for the cellular ROS assay, whereas the Figure 2 caption specifies 10 μM for the HaCaT-cell measurement.

  • Different cell types named for TGF-β1 result

    Minor

    The Results attribute the dose-dependent TGF-β1 increase to HSF cells, but the Discussion attributes it to HaCaT cells.

3 of 3

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Related

Authors
Feng, G., Wei, L., Che, H., Shen, Y., Yang, J., Mi, K., Liu, J., Wu, J., Yang, H., & Mu, L.
Affiliations
  • Kunming Medical University (CN)
  • Soochow University (CN)
  • Chinese People's Liberation Army (CN)
Corresponding author
  • Wu, Jing
  • Yang, Hailong
  • Mu, Lixian
ORCID
Venue
Frontiers in Pharmacology
Publisher
Frontiers Media SA
Published
2022-01-19
Volume
12
Pages
761011-761011
ISSN
1663-9812 (ISSN-L)
DOI
10.3389/fphar.2021.761011
PMC
PMC8807480
OpenAlex
W4206681594
Semantic Scholar
145d6405f9d5dafd89f6e099478d641e1dccd28e
Cited by
30
References
46
Citations by year
2026: 7 · 2025: 8 · 2024: 11 · 2023: 2 · 2022: 2
FWCI
5.62
Type
journal article
Language
en
Open access
Licence
Locations
  • Frontiers in Pharmacology (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Natural Science Foundation of Yunnan Province (202101AY070001-004, 2019HB023, 81673401, 82160680, 81560581, 2018FE001(-135)
  • Priority Academic Program Development of Jiangsu Higher Education Institutions
Topics
  • Health Sciences › Medicine › Dermatology › Skin Protection and Aging
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › melanin and skin pigmentation
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Hydrolysis and Bioactive Peptides
Keywords
photoaging, frog skin peptides, antioxidant peptides, reactive oxygen species scavenging, DNA damage, apoptosis, interleukin-6, TLR4 signaling, NF-κB signaling, TGF-β1/Smad2 signaling, collagen synthesis, keratinocytes, dermal fibroblasts

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Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

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