Selaginella tamariscina extract and amentoflavone ameliorate UVB-induced skin aging via AMPK activation

Abstract

Ultraviolet (UV) exposure accelerates skin aging and increases the risk of skin-related diseases. Amentoflavone (AMF), the major compound isolated from Selaginella tamariscina, exhibits potent antioxidant and anti-inflammatory activities. This study aimed to investigate the therapeutic effects and mechanisms of S. tamariscina extract (STE) and AMF on UVB-induced skin photoaging. In vitro and in vivo photoaging models were established to evaluate the protective effects of STE and AMF. The therapeutic target of AMF was identified using network pharmacology, bioinformatic analysis, and molecular docking. In vitro, STE significantly reduced UVB-induced oxidative stress, inflammation, and apoptosis. In vivo, both STE and AMF effectively mitigated UVB-induced skin injury. Mechanistically, AMF directly interacted with AMP-activated protein kinase (AMPK), thereby promoting autophagy and protecting cells from UVB-induced damage. In conclusion, STE and its active compound AMF alleviate UVB-induced photoaging via activation of the AMPK signaling pathway, supporting their potential use in skin photoaging therapy.

Keywords

Selaginella tamariscina / Amentoflavone / Photoaging / Autophagy / AMPK

Funding

This study was supported by the National Natural Science Foundation of China (Nos. 82273817, and 81973206), the China Postdoctoral Science Foundation (No. 2024M763662).

Ethics approval and consent to participate

The animal study protocol was approved by the Institutional Animal Care and Use Committee at China Pharmaceutical University (No. SYXK2021-0011).

Declaration of competing interest

No potential competing interests were reported by the authors.

References

[1] Blume-Peytavi U, Kottner J, Sterry W, et al. Age-associated skin conditions and diseases: current perspectives and future options. Gerontologist. 2016; 56(Suppl 2):S230-242. https://doi.org/10.1093/geront/gnw003.

[2] Gu YP, Han JX, Jiang CP, et al. Biomarkers, oxidative stress and autophagy in skin aging. Ageing Res Rev. 2020; 59:101036. https://doi.org/10.1016/j.arr.2020.101036.

[3] Han AN, Chien AL, Kang S. Photoaging. Dermatol Clin. 2014; 32:291-299, vii. https://doi.org/10.1016/j.det.2014.03.015.

[4] Kammeyer A, Luiten RM. Oxidation events and skin aging. Ageing Res Rev. 2015; 21:16-29. https://doi.org/10.1016/j.arr.2015.01.001.

[5] Kim CW, Alam MB, Song BR, et al. γ-Mangosteen, an autophagy enhancer, prevents skin-aging via activating KEAP1/NRF2 signaling and downregulating MAPKs/AP-1/NF-κB-mediated MMPs. Phytomedicine. 2024; 132:155815. https://doi.org/10.1016/j.phymed.2024.155815.

[6] Wang SQ, Balagula Y, Osterwalder U. Photoprotection: a review of the current and future technologies. Dermatol Ther. 2010; 23:31-47. https://doi.org/10.1111/j.1529-8019.2009.01289.x.

[7] Rittié L, Fisher GJ. UV-light-induced signal cascades and skin aging. Ageing Res Rev. 2002; 1:705-720. https://doi.org/10.1016/s1568-1637(02)00024-7.

[8] Salminen A, Kaarniranta K. AMP-activated protein kinase (AMPK) controls the aging process via an integrated signaling network. Ageing Res Rev. 2012; 11:230-241. https://doi.org/10.1016/j.arr.2011.12.005.

[9] Apfeld J, O'connor G, Mcdonagh T, et al. The AMP-activated protein kinase AAK-2 links energy levels and insulin-like signals to lifespan in C. elegans. Genes Dev. 2004; 18:3004-3009. https://doi.org/10.1101/gad.1255404.

[10] Burkewitz K, Zhang Y, Mair WB. AMPK at the nexus of energetics and aging. Cell Metab. 2014; 20:10-25. https://doi.org/10.1016/j.cmet.2014.03.002.

[11] Meléndez A, Tallóczy Z, Seaman M, et al. Autophagy genes are essential for dauer development and life-span extension in C. elegans. Science. 2003; 301:1387-1391. https://doi.org/10.1126/science.1087782.

[12] Rubinsztein DC, Mariño G, Kroemer G. Autophagy and aging. Cell. 2011; 146:682-695. https://doi.org/10.1016/j.cell.2011.07.030.

[13] Wang M, Charareh P, Lei X, et al. Autophagy: multiple mechanisms to protect skin from ultraviolet radiation-driven photoaging. Oxid Med Cell Longev. 2019; 2019:8135985. https://doi.org/10.1155/2019/8135985.

[14] Zhao YL, Lin JJ, Li JN, et al. RhFGF21 protects epidermal cells against UVB-induced apoptosis through activating AMPK-mediated autophagy. Int J Mol Sci. 2022; 23:12466. https://doi.org/10.3390/ijms232012466.

[15] Xu ZT, Fu X, Jin LJ. Chemical constituents research progress of Selaginella tamariscina. Chin J Mod Appl Pharm. 2017; 34:1779-1784. https://doi.org/10.13748/j.cnki.issn1007-7693.2017.12.030.

[16] Bailly C. The traditional and modern uses of Selaginella tamariscina (P. Beauv.) Spring, in medicine and cosmetic: applications and bioactive ingredients. J Ethnopharmacol. 2021; 280:114444. https://doi.org/10.1016/j.jep.2021.114444.

[17] Lee H, Kim SY, Lee SW, et al. Amentoflavone-enriched Selaginella rossii protects against ultraviolet- and oxidative stress-induced aging in skin cells. Life (Basel). 2022; 12:2106. https://doi.org/10.3390/life12122106.

[18] Yang JW, Pokharel YR, Kim MR, et al. Inhibition of inducible nitric oxide synthase by sumaflavone isolated from Selaginella tamariscina. J Ethnopharmacol. 2006; 105:107-113. https://doi.org/10.1016/j.jep.2005.10.001.

[19] Lee CW, Choi HJ, Kim HS, et al. Biflavonoids isolated from Selaginella tamariscina regulate the expression of matrix metalloproteinase in human skin fibroblasts. Bioorg Med Chem. 2008; 16:732-738. https://doi.org/10.1016/j.bmc.2007.10.036.

[20] De Almeida LGN, Thode H, Eslambolchi Y, et al. Matrix metalloproteinases: from molecular mechanisms to physiology, pathophysiology, and pharmacology. Pharmacol Rev. 2022; 74:712-768. https://doi.org/10.1124/pharmrev.121.000349.

[21] Park NH, Lee CW, Bae JH, et al. Protective effects of amentoflavone on Lamin A-dependent UVB-induced nuclear aberration in normal human fibroblasts. Bioorg Med Chem Lett. 2011; 21:6482-6484. https://doi.org/10.1016/j.bmcl.2011.08.067.

[22] Liu KS, Huang TH, Aljuffali IA, et al. Exploring the structure-permeation relationship of topical tricyclic antidepressants used for skin analgesia. Int J Pharm. 2017; 523:386-397. https://doi.org/10.1016/j.ijpharm.2017.03.048.

[23] Pharmacopoeia of the People’s Republic of China. Beijing: China Medical Science and Technology Press. 2020.

[24] Bhatia-Dey N, Kanherkar RR, Stair SE, et al. Cellular senescence as the causal nexus of aging. Front Genet. 2016; 7:13. https://doi.org/10.3389/fgene.2016.00013.

[25] Zhang WW, Zheng ZT, Wang TY, et al. Succinylated type I collagen regulates ferroptosis to attenuate skin photoaging. ACS Appl Mater Interfaces. 2024; 16:56744-56761. https://doi.org/10.1021/acsami.4c11952.

[26] Jabłońska-Trypuć A, Matejczyk M, Rosochacki S. Matrix metalloproteinases (MMPs), the main extracellular matrix (ECM) enzymes in collagen degradation, as a target for anticancer drugs. J Enzyme Inhib Med Chem. 2016; 31:177-183. https://doi.org/10.3109/14756366.2016.1161620.

[27] He L, He T, Farrar S, et al. Antioxidants maintain cellular redox homeostasis by elimination of reactive oxygen species. Cell Physiol Biochem. 2017; 44:532-553. https://doi.org/10.1159/000485089.

[28] Wang YJ, Wang L, Wen X, et al. NF-κB signaling in skin aging. Mech Ageing Dev. 2019; 184:111160. https://doi.org/10.1016/j.mad.2019.111160.

[29] Garcia D, Shaw RJ. AMPK: mechanisms of cellular energy sensing and restoration of metabolic balance. Mol Cell. 2017; 66:789-800. https://doi.org/10.1016/j.molcel.2017.05.032.

[30] Gao CL, Hou GG, Liu J, et al. Synthesis and target identification of benzoxepane derivatives as potential anti-neuroinflammatory agents for ischemic stroke. Angew Chem Int Ed Engl. 2020; 59:2429-2439. https://doi.org/10.1002/anie.201912489.

[31] Kaushik S, Tasset I, Arias E, et al. Autophagy and the hallmarks of aging. Ageing Res Rev. 2021; 72:101468. https://doi.org/10.1016/j.arr.2021.101468.

[32] Park JM, Lee DH, Kim DH. Redefining the role of AMPK in autophagy and the energy stress response. Nat Commun. 2023; 14:2994. https://doi.org/10.1038/s41467-023-38401-z.

[33] Yang F, Qin Y, Wang YQ, et al. Metformin inhibits the NLRP3 inflammasome via AMPK/mTOR-dependent effects in diabetic cardiomyopathy. Int J Biol Sci. 2019; 15:1010-1019. https://doi.org/10.7150/ijbs.29680.

[34] Zhu JP, Zhang ZZ, Yang QY, et al. Metformin attenuates sevoflurane-induced neurocognitive impairment through AMPK-ULK1-dependent autophagy in aged mice. Brain Res Bull. 2020; 157:18-25. https://doi.org/10.1016/j.brainresbull.2020.01.018.

[35] Tang XY, Yang TY, Yu DJ, et al. Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin. Environ Int. 2024; 185:108535. https://doi.org/10.1016/j.envint.2024.108535.

[36] Ansary TM, Hossain MR, Kamiya K, et al. Inflammatory molecules associated with ultraviolet radiation-mediated skin aging. Int J Mol Sci. 2021; 22:3974. https://doi.org/10.3390/ijms22083974.

[37] Heck DE, Vetrano AM, Mariano TM, et al. UVB light stimulates production of reactive oxygen species: unexpected role for catalase. J Biol Chem. 2003; 278:22432-22436. https://doi.org/10.1074/jbc.C300048200.

[38] Chen HY, Lin CH, Wu Y, et al. Protective effects of degraded Bletilla striata polysaccharides against UVB-induced oxidative stress in skin. Int J Biol Macromol. 2024; 277:134462. https://doi.org/10.1016/j.ijbiomac.2024.134462.

[39] Kim SH, Lee SE, Kim SJ, et al. Protective effects of an electrophilic metabolite of docosahexaenoic acid on UVB-induced oxidative cell death, dermatitis, and carcinogenesis. Redox Biol. 2023; 62:102666. https://doi.org/10.1016/j.redox.2023.102666.

[40] Lei Yl, Wang K, Deng Lf, et al. Redox regulation of inflammation: old elements, a new story. Med Res Rev. 2015; 35:306-340. https://doi.org/10.1002/med.21330.

[41] Chen WQ, Kang J, Xia JP, et al. p53-related apoptosis resistance and tumor suppression activity in UVB-induced premature senescent human skin fibroblasts. Int J Mol Med. 2008; 21:645-653. https://doi.org/10.3892/ijmm.21.5.645.

[42] Tang XW, Zhu YC, Han LD, et al. CP-31398 restores mutant p53 tumor suppressor function and inhibits UVB-induced skin carcinogenesis in mice. J Clin Invest. 2007; 117:3753-3764. https://doi.org/10.1172/jci32481.

[43] Nagase H, Visse R, Murphy G. Structure and function of matrix metalloproteinases and TIMPs. Cardiovasc Res. 2006; 69:562-573. https://doi.org/10.1016/j.cardiores.2005.12.002.

[44] Kim C, Ryu HC, Kim JH. Low-dose UVB irradiation stimulates matrix metalloproteinase-1 expression via a BLT2-linked pathway in HaCaT cells. Exp Mol Med. 2010; 42:833-841. https://doi.org/10.3858/emm.2010.42.12.086.

[45] Mizushima N, Levine B.Autophagy in human diseases. N Engl J Med. 2020; 383:1564-1576. https://doi.org/10.1056/NEJMra2022774.

[46] Ravikumar B, Sarkar S, Davies JE, et al. Regulation of mammalian autophagy in physiology and pathophysiology. Physiol Rev. 2010; 90:1383-1435. https://doi.org/10.1152/physrev.00030.2009.

[47] Zou L, Liao MR, Zhen YQ, et al. Autophagy and beyond: Unraveling the complexity of UNC-51-like kinase 1 (ULK1) from biological functions to therapeutic implications. Acta Pharm Sin B. 2022; 12:3743-3782. https://doi.org/10.1016/j.apsb.2022.06.004.

[48] Codogno P, Mehrpour M, Proikas-Cezanne T. Canonical and non-canonical autophagy: variations on a common theme of self-eating? Nat Rev Mol Cell Biol. 2011; 13:7-12.https://doi.org/10.1038/nrm3249

[49] Ke J, Wang J, Wu X, et al. Salidroside ameliorates ultraviolet-induced keratinocyte injury by inducing SIRT1-dependent autophagy. Clin Cosmet Investig Dermatol. 2022; 15:1499-1508. https://doi.org/10.2147/ccid.S367233.

[50] Egan DF, Shackelford DB, Mihaylova MM, et al. Phosphorylation of ULK1 (hATG1) by AMP-activated protein kinase connects energy sensing to mitophagy. Science. 2011; 331:456-461. https://doi.org/10.1126/science.1196371.

[51] Herzig S, Shaw RJ. AMPK: guardian of metabolism and mitochondrial homeostasis. Nat Rev Mol Cell Biol. 2018; 19:121-135. https://doi.org/10.1038/nrm.2017.95.

[52] Matsuzawa-Ishimoto Y, Hwang S, Cadwell K. Autophagy and inflammation. Annu Rev Immunol. 2018; 36:73-101. https://doi.org/10.1146/annurev-immunol-042617-053253.

[53] Du JF, Xu Q, Zhao H, et al. PI3K inhibitor 3-MA promotes the antiproliferative activity of esomeprazole in gastric cancer cells by downregulating EGFR via the PI3K/FOXO3a pathway. Biomed Pharmacother. 2022; 148:112665. https://doi.org/10.1016/j.biopha.2022.112665.