Nonalcoholic fatty liver disease (NAFLD), which promotes serious health problems, is related to the increase in the nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome and pyroptosis by a high-fat diet (HFD). Whether dieckol (DK), a component of Ecklonia cava extracts (ECE), attenuated NAFLD in an HFD-induced NAFLD animal model was evaluated. The expression of high mobility group box 1/Toll-like receptor 4/nuclear factor-κB, which initiated the NLRP3 inflammasome, was increased in the liver of HFD-fed animals and significantly decreased with ECE or DK administration. The expression of NLRP3/ASC/caspase-1, which are components of the NLRP3 inflammasome, and the number of pyroptotic cells were increased by HFD and decreased with ECE or DK administration. The accumulation of triglycerides and free fatty acids in the liver was increased by HFD and decreased with ECE or DK administration. The histological NAFLD score was increased by HFD and decreased with ECE or DK administration. The expression of lipogenic genes (FASN, SREBP-2, PPARγ, and FABP4) increased and that of lipolytic genes (PPARα, CPT1A, ATGL, and HSL) was decreased by HFD and attenuated with ECE or DK administration. In conclusion, ECE or DK attenuated NAFLD by decreasing the NLRP3 inflammasome and pyroptosis.

It is well-known that increased oxidative stress caused by ultraviolet B (UV-B) radiation induces melanogenesis and activates metalloproteinases (MMPs), which degrade collagen and elastin fibers, leading to decreased skin elasticity. Various antioxidant agents, such as vitamin C and niacinamide, have been evaluated for use as treatments for photoaging or skin pigmentation. In this study, we evaluated the ability of a topical liquid formula of polydeoxyribonucleotide (PDRN), vitamin C, and niacinamide (PVN) delivered via a microneedling therapy system (MTS) to attenuate photoaging and pigmentation by increasing nuclear factor erythroid 2-like 2 (NRF2)/heme oxygenase-1 (HO-1) and decreasing MMP expression in a UV-B-radiated animal model. The effects of the PVN were compared with those of individual PDRN and hydroquinone (HQ) compounds. The expression of NRF2/HO-1 significantly increased in response to HQ, PDRN, and PVN in UV-B-radiated animal skin. The activity of nicotinamide adenine dinucleotide phosphate hydrogen oxidase decreased in response to HQ, PDRN, and PVN, and the superoxide dismutase activity increased. The expression of tumor protein p53 and microphthalmia-associated transcription factor and tyrosinase activity decreased in response to HQ, PDRN, and PVN, and this decrease was accompanied by decreased melanin content in the skin. The expression of nuclear factor kappa-light-chain enhancer of activated B cells and MMP2/3/9 decreased in response to HQ, PDRN, and PVN in UV-B-radiated skin. However, the expression of collagen type I α1 chain and the amount of collagen fibers that were evaluated by Masson’s trichrome staining increased in response to HQ, PDRN, and PVN. The contents of elastin fibers, fibrillin 1/2 and fibulin 5 increased in response to HQ, PDRN, and PVN. In conclusion, PVN delivered via MTS led to decreased melanogenesis and destruction of collagen and elastin fibers by MMPs, and, thus, PVN decreased skin pigmentation and increased skin elasticity.

It is well known that skin aging is related to the destruction of collagen and elastin fibers by metalloproteinases (MMPs). Aged fibroblasts have a decreased ability to synthesize collagen and elastin. Nuclear factor erythroid 2-related factor 2 (NRF2) involves glyoxalase (GLO) activation, which inhibits the production of advanced glycated end products (AGE) and the expression of its receptor (RAGE). RAGE increases nuclear transcription factor-kappa B (NF-κB), which upregulates MMPs and decreases skin elasticity. NRF2 also decreases M1 macrophages, which secrete tumor necrosis factor-alpha (TNF-α), thereby decreasing AGE production. It is well known that radiofrequency (RF) decreases skin elasticity by increasing collagen synthesis. We evaluated whether RF increases skin elasticity via NRF2/GLO and whether they decrease AGE and RAGE expression in aged animal skin. We also compared the effects of RF based on the modes (monopolar or bipolar) or the combination used. In aged skin, NRF2, GLO-1, and M2 macrophage expression was decreased, and their expression increased when RF was applied. M1 and TNF-α demonstrated increased expression in the aged skin and decreased expression after RF application. AGE accumulation and RAGE, NF-κB, and MMP2/3/9 expression were increased in the aged skin, and they were decreased by RF. The papillary and reticular fibroblast markers showed decreased expression in young skin and increased expression in aged skin. The densities of collagen and elastin fiber in the aged skin were low, and they were increased by RF. In conclusion, RF leads to increased collagen and elastin fibers by increasing NRF2/GLO-1 and modulating M1/M2 polarization, which leads to decreased AGE and RAGE and, consequently, decreased NF-κB, which eventually slows collagen and elastin destruction. RF also leads to increased collagen and elastin fiber synthesis by increasing papillary and reticular fibroblast expression.

Vascular calcification (VC) is induced by a decrease in sirtuin 3 (SIRT3) and superoxide dismutase (SOD)2 and increases mitochondrial reactive oxygen species (mtROS), eventually leading to mitochondrial dysfunction and phenotype alterations in vascular smooth muscle cells (VSMCs) into osteoblast-like cells in hypertension. Ecklonia cava extract (ECE) is known to increase peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α) and SOD2. In this study, we evaluated the effect of ECE on decreasing VC by increasing PGC-1α which increased SOD2 activity and decreased mtROS in an in vitro VSMC model of treating serums from Wistar Kyoto (WKY), spontaneous hypertensive rats (SHRs), and ECE-treated SHRs. Furthermore, the decreasing effect of ECE on VC was evaluated with an in vivo SHR model. PGC-1α expression, SIRT3 expression, and SOD2 activity were decreased by the serum from the SHRs and increased by the serum from the ECE-treated SHRs in the VSMCs. PGC-1α silencing eliminated those increases. mtROS generation and mitochondrial DNA (mtDNA) damage increased in the SHRs but decreased with ECE. Mitochondrial fission increased in the SHRs but decreased by ECE. Mitochondrial fusion, mitophagy, and mitochondrial biogenesis were decreased in the SHRs but increased by ECE. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and calcium deposition in the medial layer of the aorta increased in the SHRs but decreased with ECE. Therefore, ECE decreases VC via the upregulation of PGC-1α and SIRT3, which increases SOD2 activity. Activated SOD2 decreases mtDNA damage and mtROS generation, which sequentially decreases NADPH oxidase activity and changes the mitochondrial dynamics, thereby decreasing VC.

Nicotinamide nucleotide transhydrogenase (NNT) is involved in decreasing melanogenesis through tyrosinase degradation induced by cellular redox changes. Nicotinamide is a component of coenzymes, such as NAD⁺, NADH, NADP⁺, and NADPH, and its levels are modulated by NNT. Vitamin C and polydeoxyribonucleotide (PDRN) are also known to decrease skin pigmentation. We evaluated whether a mixture of nicotinamide, vitamin C, and PDRN (NVP-mix) decreased melanogenesis by modulating mitochondrial oxidative stress and NNT expression in UV-B-irradiated animals and in an in vitro model of melanocytes treated with conditioned media (CM) from UV-B-irradiated keratinocytes. The expression of NNT, GSH/GSSG, and NADPH/NADP⁺ in UV-B-irradiated animal skin was significantly decreased by UV-B radiation but increased by NVP-mix treatment. The expression of NNT, GSH/GSSG, and NADPH/NADP⁺ ratios decreased in melanocytes after CM treatment, although they increased after NVP-mix administration. In NNT-silenced melanocytes, the GSH/GSSG and NADPH/NADP⁺ ratios were further decreased by CM compared with normal melanocytes. NVP-mix decreased melanogenesis signals, such as MC1R, MITF, TYRP1, and TYRP2, and decreased melanosome transfer-related signals, such as RAB32 and RAB27A, in UV-B-irradiated animal skin. NVP-mix also decreased MC1R, MITF, TYRP1, TYRP2, RAB32, and RAB27A in melanocytes treated with CM from UV-irradiated keratinocytes. The expression of MC1R and MITF in melanocytes after CM treatment was unchanged by NNT silencing. However, the expression of TYRP1, TYRP2, RAB32, and RAB27A increased in NNT-silenced melanocytes after CM treatment. NVP-mix also decreased tyrosinase activity and melanin content in UV-B-irradiated animal skin and CM-treated melanocytes. In conclusion, NVP-mix decreased mitochondrial oxidative stress by increasing NNT expression and decreased melanogenesis by decreasing MC1R/MITF, tyrosinase, TYRP1, and TYRP2.

Poly L-lactic acid (PLLA) fillers stimulate collagen synthesis by activating various immune cells and fibroblasts. Piezo1, an ion channel, responds to mechanical stimuli, including changes in extracellular matrix stiffness, by mediating Ca²⁺ influx. Given that elevated intracellular Ca²⁺ levels trigger signaling pathways associated with fibroblast proliferation, Piezo1 is a pivotal regulator of collagen synthesis and tissue fibrosis. The aim of the present study was to investigate the impact of PLLA on dermal collagen synthesis by activating Piezo1 in both an H₂O₂-induced cellular senescence model in vitro and aged animal skin in vivo. PLLA elevated intracellular Ca²⁺ levels in senescent fibroblasts, which was attenuated by the Piezo1 inhibitor GsMTx4. Furthermore, PLLA treatment increased the expression of phosphorylated ERK1/2 to total ERK1/2 (pERK1/2/ERK1/2) and phosphorylated AKT to total AKT (pAKT/AKT), indicating enhanced pathway activation. This was accompanied by upregulation of cell cycle-regulating proteins (CDK4 and cyclin D1), promoting the proliferation of senescent fibroblasts. Additionally, PLLA promoted the expression of phosphorylated mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III in senescent fibroblasts, with GsMTx4 treatment mitigating these effects. In aged skin, PLLA treatment similarly upregulated the expression of pERK1/2/ERK1/2, pAKT/AKT, CDK4, cyclin D1, mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III. In summary, our findings suggest Piezo1′s involvement in PLLA-induced collagen synthesis, mediated by heightened activation of cell proliferation signaling pathways such as pERK1/2/ERK1/2, pAKT/AKT, and phosphorylated mTOR/S6K1/4EBP1, underscoring the therapeutic potential of PLLA in tissue regeneration.