Enhanced Nrf2 up-regulation by extracellular basic pH in a human skin equivalent system.

Extracellular basic pH regulates cellular processes in wounds, and consequently influenced wound healing. Oxidative defence system modulation in the skin helps heal wounds, inhibits skin ageing and improves the skin condition. Moreover, the role of keratinocyte growth factor (KGF) and nuclear factor erythroid 2-related factor 2 (Nrf2) in antioxidant systems has been reported in various skin models. However, the effects of extracellular basic pH on wound- or skin ageing-related skin damage have not been examined. Thus, we investigated the antioxidant systems affected by extracellular basic pH in a 3D human skin equivalent system (3HSE). Extracellular basic pH decreased KGF expression and enhanced the oxidative defence system, and thus activated Nrf2 in the 3HSE. Additionally, extracellular basic pH and KGF treatment up-regulated Nrf2 activation and its regulation of the oxidative defence system in the 3HSE. This indicates that Nrf2 up-regulation is enhanced by reactive oxygen species production, rather than KGF, and by extracellular basic pH of the skin. The inhibition of skin damage through pH imbalance and KGF regulation suggests that the development of pH-regulating or pH-maintaining materials may provide effective therapeutic strategies for maintaining a healthy skin.

Cera Flava Alleviates Atopic Dermatitis by Activating Skin Barrier Function via Immune Regulation.

Cera Flava (CF), a natural extract obtained from beehives, is widely used in dermatological products owing to its wound healing, wrinkle reduction, UV-protective, and skin cell turnover stimulation effects. However, its effect on AD-like skin lesions is unknown. In this study, we used a mouse model of AD to evaluate the effects of CP at the molecular and phenotypic levels. Topical house dust mite (HDM) sensitization and challenge were performed on the dorsal skin of NC/Nga mice to induce AD-like cutaneous lesions, phenotypes, and immunologic responses. The topical application of CF for 6 weeks relieved HDM-induced AD-like phenotypes, as quantified by the dermatitis severity score, scratching frequency, and skin moisture. CP decreased immunoglobulin E, histamine, and thymic stromal lymphopoietin levels. Histopathological analysis showed that CF decreased epidermal thickening and the number of mast cells. CF attenuated HDM-induced changes in the expression of skin barrier-related proteins. Furthermore, CF decreased the mRNA levels of inflammatory factors, including interleukin (IL)-1ß, IL-4, IL-13, IL-8, TARC, MDC, and RANTES, in dorsal skin tissue via the TLR2/MyD88/TRAF6/ERK pathway. CF influences skin barrier function and immune regulation to alleviate AD symptoms. It may therefore be an effective alternative to topical steroids for the treatment of AD.

Role of melatonin as an SIRT1 enhancer in chronic obstructive pulmonary disease induced by cigarette smoke.

BACKGROUND: Melatonin has various biological activities that improve the health of an individual. We evaluated the effects of melatonin on inflammatory response in chronic obstructive pulmonary disease (COPD), focusing on the regulation of SIRT1 expression. METHODS: To investigate the effect of melatonin, we used cigarette smoke (CS)-induced COPD mouse model and CS condensate (CSC)-stimulated J774 macrophage cells. RESULTS: CSC-stimulated J774 macrophages exhibited increased p65 acetylation with a reduction in SIRT1 expression. However, melatonin induced the enhancement of SIRT1 expression, which eventually decreased p65 acetylation in CSC-stimulated J774 cells. Melatonin-treated mice exhibited an enhancement in SIRT1 expression with the reduction in p65 acetylation, which decreased the level of inflammatory mediators induced by CS. Additionally, SIRT1 inhibitor treatment increased the level of inflammatory mediators, which was accompanied by an increase in p65 acetylation. However, cotreatment with melatonin and an SIRT1 inhibitor reduced the level of inflammatory mediators compared with that by treatment with the SIRT1 inhibitor alone, which was accompanied by elevation in SIRT1 expression and reduction in p65 acetylation. CONCLUSIONS: Overall, the results indicated that melatonin has therapeutic effects against COPD, owing to its property to enhance SIRT1 expression.

Dual actions on gout flare and acute kidney injury along with enhanced renal transporter activities by Yokuininto, a Kampo medicine.

BACKGROUND: Prolonged hyperuricemia is associated with kidney disease or gouty arthritis. Whether Yokuininto, a commercially available Kampo medicine that has been used for osteoarthritis or rheumatoid arthritis, can exhibit anti-hyperuricemic and inflammatory effects remains elusive. In the present study, Yokuininto exerts multiple homeostatic action on serum uric acid (sUA) levels by blocking pro-inflammatory cytokine activities and inducing uricosuric function with anti-renal injury functions. METHODS: The sUA was measured in potassium oxonate (PO)-administered mice. Renal transporter uptake assays were performed using HEK293 cells overexpressing OAT1, OCT2 or OAT3, MDCKII cells overexpressing BCRP, and Xenopus oocytes overexpressing OAT3 or URAT1. Immunoblot and ELISA assays were performed to detect the molecules (OAT3, GLUT9, XO, NGAL, KIM-1 and IL-1α) in various human kidney cell lines. Cell viability analysis was performed to evaluate the cytotoxicity of Yokuininto [Ephedrine + pseudoephedrine 21.94%; Paeoniflorin 35.40% and Liquiritin 16.21% relatively measured by the ratios (HR-MS2 intensity / HR-MS1 intensity)]. RESULTS: Yokuininto (300 mg/kg) significantly reduced sUA by approximately 44% compared to that of PO-induced mice. The OAT3 levels were decreased in PO-induced hyperuricemic condition, whereas the GLUT9 transporter levels were markedly increased. However, PO did not alter the levels of URAT1. Yokuininto significantly inhibited the lipopolysaccharide (LPS)-induced secretion of IL-1α by approximately 63.2% compared to the LPS-treated macrophages. In addition, Yokuininto inhibited nitric oxide synthesis by approximately 33.7 (500 µg/mL) and 64.6% (1000 µg/mL), compared to that of LPS-treated macrophages. Yokuininto markedly increased xanthine oxidase inhibition activity. Furthermore, interleukin-1α (IL-1α), a pro-inflammatory cytokine, elevated neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) activities in LLC-PK1 cells. Expression of renal inflammatory biomarkers, NGAL and KIM-1, was reduced under the Yokuininto treatment by 36.9 and 72.1%, respectively. CONCLUSIONS: Those results suggest that Yokuininto may suppress inflammation and protect against kidney dysfunction in hyperuricemia. The present findings demonstrated that Yokuininto lowered sUA through both increased uric acid excretion and decreased uric acid production. Our results may provide a basis for the protection of prolonged hyperuricemia-associated kidney injury with uric acid-lowering agents such as Yokuininto.

Therapeutic Effect of Dipsacus asperoides C. Y. Cheng et T. M. Ai in Ovalbumin-Induced Murine Model of Asthma.

Dipsacus asperoides C. Y. Cheng et T. M. Ai (DA) has been used in China as a traditional medicine to treat lumbar and knee pain, liver dysfunction, and fractures. We explored the suppressive effect of DA on allergic asthma using an ovalbumin (OVA)-induced asthma model. In the asthma model, female Balb/c mice were sensitized to OVA on day 0 and 14 to boost immune responses and then exposed to OVA solution by using an ultrasonic nebulizer on days 21 to 23. DA (20 and 40 mg/kg) was administered to mice by oral gavage on days 18 to 23. Methacholine responsiveness was determined on day 24 using a plethysmography. On day 25, we collected bronchoalveolar lavage fluid, serum, and lung tissue from animals under anesthesia. DA treatment effectively inhibited methacholine responsiveness, inflammatory cell infiltration, proinflammatory cytokines such as interleukin (IL)-5 and IL-13, and immunoglobulin (Ig) E in OVA-induced asthma model. Reductions in airway inflammation and mucus hypersecretion, accompanied by decreases in the expression of inducible nitric oxide synthase (iNOS) and the phosphorylation of nuclear factor kappa B (NF-κB), were also observed. Our results indicated that DA attenuated the asthmatic response, and that this attenuation was closely linked to NF-κB suppression. Thus, this study suggests that DA is a potential therapeutic for allergic asthma.

Melatonin inhibits neuronal dysfunction-associated with neuroinflammation by atopic psychological stress in NC/Nga atopic-like mouse models.

Atopic dermatitis (AD), also known as atopic eczema, is chronic pruritic skin disease. AD can increase psychological stress as well, increasing glucocorticoid release and exacerbating the associated symptoms. Chronic glucocorticoid elevation disturbs neuroendocrine signaling and can induce neuroinflammation, neurotoxicity, and cognitive impairment; however, it is unclear whether AD-related psychological stress elevates glucocorticoids enough to cause neuronal damage. Therefore, we assessed the effects of AD-induced stress in a mouse AD model. AD-related psychological stress increased astroglial and microglial activation, neuroinflammatory cytokine expression, and markers of neuronal loss. Notably, melatonin administration inhibited the development of skin lesions, scratching behavior, and serum IgE levels in the model mice, and additionally caused a significant reduction in corticotropin-releasing hormone responsiveness, and a significant reduction in neuronal damage. Finally, we produced similar results in a corticosterone-induced AD-like skin model. This is the first study to demonstrate that AD-related psychological stress increases neuroendocrine dysfunction, exacerbates neuroinflammation, and potentially accelerates other neurodegenerative disease states.

Acceleration of Apoptosis by Extracellular Basic pH in a 3D Human Skin Equivalent System.

Previously, we have shown that extracellular basic pH plays a significant role in both the direct and indirect regulation of cellular processes in a wound; this in turn affects the wound-healing process. Several studies have demonstrated the importance of apoptosis modulation in the wound-healing process, especially in removing inflammatory cells and in inhibiting scar formation. However, the effects of extracellular basic pH on wound healing-related skin damage are yet to be examined. Therefore, we investigated the induction of accelerated apoptosis by extracellular basic pH in skin. Apoptosis-related protein levels were measured using an array kit, target protein expression levels were detected by immunostaining, lactate dehydrogenase was analyzed spectrophotometrically, and Annexin V levels were measured by fluorescence staining. Basic pH (8.40) strongly upregulated extrinsic apoptosis proteins (Fas, high temperature requirement A, and p21) and slightly upregulated intrinsic apoptosis proteins (cytochrome c, B-cell lymphoma 2 [Bcl-2], Bcl-2-associated death promoter, and Bcl-2-like protein 4) in a 3D human skin equivalent system. Moreover, basic pH (8.40) induced heat shock protein (HSP) 60 and 70. In addition, basic pH-exposed Fas- and HSP60-knockdown cells showed significantly decreased levels of apoptosis. Taken together, these results indicate that extracellular basic pH increases early-stage apoptosis through Fas/FasL via modulation of HSP60 and HSP70.

Assessing the recovery from prerenal and renal acute kidney injury after treatment with single herbal medicine via activity of the biomarkers HMGB1, NGAL and KIM-1 in kidney proximal tubular cells treated by cisplatin with different doses and exposure times.

BACKGROUND: Acute kidney injury (AKI) is an initial factor in many kidney disorders. Pre- and intra-renal AKI biomarkers have recently been reported. Recovery from AKI by herbal medicine has rarely been reported. Thus, this study aimed to investigate the dose- and time-dependent effects of herbal medicines to protect against AKI in cisplatin-induced human kidney 2 (HK-2) cells by assessing the activities of high-mobility group box protein 1 (HMGB1), neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). METHODS: Proximal tubular HK-2 cell lines were treated with either 400 µM of cisplatin for 6 h or 10 µM of cisplatin for 24 h and then exposed to ten types of single herbal medicines, including Nelumbo nymphaea (NY) at a dose of 100 µg/mL. The AKI biomarkers HMGB1, NGAL and KIM-1 were repeatedly measured by an ELISA assay at 2, 4, and 6 h in the group treated with 400 µM of cisplatin to confirm necrotic cell death and at 6, 24, and 48 h in the group treated with 10 µM of cisplatin to examine apoptotic cell death. Recovery confirm was conducted through in vivo study using ICR mice for 3 day NY or Paeonia suffruticosa intake. RESULTS: Cisplatin treatment at a concentration of 10 µM decreased cell viability. Treatment with 400 µM of cisplatin reduced HMBG1 activity and resulted in lactate dehydrogenase release. In longer exposure durations (up to 48 h), NGAL and KIM-1 exhibited activity from 24 h onward. Additionally, NY treatment resulted in an approximately 50% change in all three biomarkers. The time-dependent profiles of HMGB1, NGAL and KIM-1 activities up to 48 h were notably different; HMGB1 exhibited a 7-fold change at 6 h, and NGAL and KIM-1 exhibited 1.7-fold changes at 24 h, respectively. Consistently, serum and urine NGAL and KIM-1 activities were all reduced in ICR mice. CONCLUSIONS: Several single herbal medicines, including NY, have a potential as effectors of AKI due to their ability to inhibit the activation of HMGB1, NGAL and KIM-1 in an in vitro AKI-mimicked condition and simple in vivo confirm. Furthermore, an in vivo proof-of-concept study is needed.

6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway.

Allergic dermatitis (AD) clinically presents with skin erythematous plaques, eruption, and elevated serum IgE, and T helper cell type 2 and 1 (Th2 and Th1) cytokine levels. 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown anti-inflammatory effects, but its inhibitory effects on AD are unknown. The aim of this study was to examine whether 6-shogaol inhibits AD-like skin lesions and their underlying mechanism in vivo and in vitro. An AD-like response was induced by tumor necrosis factor-α (TNF-α)+IFN-γ in human keratinocytes or by 2,4-dinitrochlorobenzene (DNCB) in mice. In vivo, 6-shogaol inhibited the development of DNCB-induced AD-like skin lesions and scratching behavior, and showed significant reduction in Th2/1-mediated inflammatory cytokines, IgE, TNF-α, IFN-γ, thymus and activation-regulated chemokine, IL-1, 4, 12, and 13, cyclooxygenase-2, and nitric oxide synthase levels. In vitro, 6-shogaol inhibited reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling, and increased the levels of total glutathione, heme oxygenase-1, and quinone 1 via nuclear factor erythroid 2 related factor 2 (Nrf2) activation. 6-Shogaol can alleviate AD-like skin lesions by inhibiting immune mediators via regulating the ROS/MAPKs/Nrf2 signaling pathway, and may be an effective alternative therapy for AD.

Protection on Skin Aging Mediated by Antiapoptosis Effects of the Water Lily (Nymphaea Tetragona Georgi) via Reactive Oxygen Species Scavenging in Human Epidermal Keratinocytes.

AIMS: The water lily (WL) is found in Europe, Asia, and North America. WL reportedly has various pharmacological activities that improve the activities of daily life in humans. To our knowledge, no previous study has investigated about the aspect of protection on skin aging due to the mitochondria-mediated antiapoptosis effects of WL rhizome extract (WLRE) on human epidermal keratinocytes. METHODS: Human epidermal keratinocytes cells were treated with WLRE (100, 200, and 400 µg/ml) for 1 h and then with ultraviolet radiation B (UVB) (50 mJ/cm2) for another 23 h. The levels of lactate dehydrogenase, reactive oxygen species (ROS), MitoTracker, caspase-3, and glutathione were analyzed spectrophotometrically. Also, the levels of B-cell lymphoma 2 (Bcl-2) family proteins were determined with immunohistochemistry or western blotting. RESULTS: We investigated the protective effects of WLRE against UVB-induced mitochondria-mediated apoptosis. WLRE significantly and concentrations-dependently reduced UVB-induced apoptotic cytotoxicity. Furthermore, WLRE decreased ROS generation, mitochondrial dysfunction, Bcl-2-associated X protein levels, and cytochrome c release from mitochondria while increasing Bcl-2 protein levels as assessed. Moreover, WLRE inhibited caspase-3 activity and expression, indicating the inhibition of the apoptotic cascade, and induced increased levels of total glutathione, heme oxygenase 1, and radical-scavenging activity. CONCLUSION: Together, these results demonstrate that WLRE can protect human epidermal keratinocytes against UVB-induced mitochondria-mediated apoptosis by regulating ROS-eliminating pathways.

Acceleration of Collagen Breakdown by Extracellular Basic pH in Human Dermal Fibroblasts.

BACKGROUND/AIMS: Wound healing is a complex regeneration process involving the degradation and reassembly of connective tissues and skin layers. Previous studies have shown that pH plays a significant role in both the direct and indirect regulation of cellular processes in the wound, which, in turn, affect the wound healing process. However, the effects of pH on the collagen breakdown component of wound healing have yet to be investigated. Therefore, we investigated the induction of accelerated collagen breakdown by pH imbalance in the skin. METHODS: Na+/H+ exchanger and metalloproteinase (MMP)-1 were analyzed spectrophotometrically, and the expression of collagen type-I-alpha-1 (COL1A1) and mitogen-activated protein kinase (MAPK) was measured by Western blotting. RESULTS: Accelerated collagen breakdown induced by extracellular basic pH via the overproduction of reactive oxygen species (ROS) and MAPK signaling was examined in skin fibroblasts and in a three-dimensional human skin equivalent system. Basic pH (>7.50) upregulated MMP-1 and downregulated COL1A1 levels via ROS generation and MAPK signaling pathways. Acidic pH (<6.04) slightly upregulated MMP-1 and slightly downregulated COL1A1 levels via ROS generation and the p38 signaling pathway. CONCLUSION: Our results indicate that skin pH is an important effector of collagen formation in wound healing. This finding will aid in the development of new pH-targeted therapeutic strategies.

In Vitro and in Vivo Neuroprotective Effects of Walnut (Juglandis Semen) in Models of Parkinson's Disease.

Monoamine oxidase (MAO) catalyzes the oxidative deamination of monoamines including dopamine (DA). MAO expression is elevated in Parkinson's disease (PD). An increase in MAO activity is closely related to age, and this may induce neuronal degeneration in the brain due to oxidative stress. MAO (and particularly monoamine oxidase B (MAO-B)) participates in the generation of reactive oxygen species (ROS), such as hydrogen peroxide that are toxic to dopaminergic cells and their surroundings. Although the polyphenol-rich aqueous walnut extract (JSE; an extract of Juglandis Semen) has been shown to have various beneficial bioactivities, no study has been dedicated to see if JSE is capable to protect dopaminergic neurons against neurotoxic insults in models of PD. In the present study we investigated the neuroprotective potential of JSE against 1-methyl-4-phenylpyridinium (MPP⁺)- or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicities in primary mesencephalic cells and in a mouse model of PD. Here we show that JSE treatment suppressed ROS and nitric oxide productions triggered by MPP⁺ in primary mesencephalic cells. JSE also inhibited depletion of striatal DA and its metabolites in vivo that resulted in significant improvement in PD-like movement impairment. Altogether our results indicate that JSE has neuroprotective effects in PD models and may have potential for the prevention or treatment of PD.

Artemisinin protects dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity in a mouse model of Parkinson's disease.

Artemisinin is an antimalarial drug that has been used for almost half a century. However, the anti-Parkinson's disease (PD) effects of artemisinin with respect to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced oxidative stress have not yet been investigated while focusing on NF-E2-related factor 2 (Nrf2) signaling. Thus, we sought to assess the behavioral and oxidative mechanistic effects of artemisinin on MPTP-induced toxicity via the Nrf2 signaling pathway. We explored this through immunohistochemical assays, ELISA, in differentiated PC12 cells treated with siRNA, and with a PD mouse model. Artemisinin increased Nrf2 DNA-binding activity and HO-1 and NQO1 expression. Artemisinin treatment protected cells against MPP+ -induced neuronal death signaling, including NADH dehydrogenase activity, reactive oxygen species, mitochondrial membrane potential, and cleaved caspase-3. Moreover, it protected cells against MPTP-induced behavioral impairments and significantly reduced dopaminergic neuronal loss. Additionally, Nrf2 pre-inhibition using ML385 neutralized the inhibitory effects of artemisinin on dopaminergic neuronal damage and behavioral impairments induced by MPTP. Our results suggest that artemisinin inhibits MPTP-induced behavioral and neurotoxic effects in mice. This provides a foundation for further research to evaluate artemisinin as a potential therapeutic agent for PD.

Anti-Oxidative Bioactivities of Medicinal Herbs in the Treatment of Aging-Related Diseases.

Over the last 20 years, significant progress has been made in understanding the biology of aging and lifespans [...].

Chronic ultraviolet irradiation induces memory deficits via dysregulation of the dopamine pathway.

The effects of ultraviolet (UV) radiation on brain function have previously been investigated; however, the specific neurotransmitter-mediated mechanisms responsible for UV radiation-induced neurobehavioral changes remain elusive. In this study, we aimed to explore the mechanisms underlying UV radiation-induced neurobehavioral changes. In a mouse model, we observed that UV irradiation of the skin induces deficits in hippocampal memory, synaptic plasticity, and adult neurogenesis, as well as increased dopamine levels in the skin, adrenal glands, and brain. Chronic UV exposure altered the expression of genes involved in dopaminergic neuron differentiation. Furthermore, chronic peripheral dopamine treatments resulted in memory deficits. Systemic administration of a dopamine D1/D5 receptor antagonist reversed changes in memory, synaptic plasticity, adult neurogenesis, and gene expression in UV-irradiated mice. Our findings provide converging evidence that chronic UV exposure alters dopamine levels in the central nervous system and peripheral organs, including the skin, which may underlie the observed neurobehavioral shifts, such as hippocampal memory deficits and impaired neurogenesis. This study underscores the importance of protection from UV exposure and introduces the potential of pharmacological approaches targeting dopamine receptors to counteract the adverse neurological impacts of UV exposure.

6-Shogaol, an active compound of ginger, protects dopaminergic neurons in Parkinson's disease models via anti-neuroinflammation.

AIM: 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown various neurobiological and anti-inflammatory effects. The aim of this study was to examine the effects of 6-shogaol on neuroinflammatory-induced damage of dopaminergic (DA) neurons in Parkinson's disease (PD) models. METHODS: Cultured rat mesencephalic cells were treated with 6-shogaol (0.001 and 0.01 µmol/L) for 1 h, then with MPP(+)(10 µmol/L) for another 23 h. The levels of TNF-α and NO in medium were analyzed spectrophotometrically. C57/BL mice were administered 6-shogaol (10 mg·kg(-1)·d(-1), po) for 3 d, and then MPTP (30 mg/kg, ip) for 5 d. Seven days after the last MPTP injection, behavioral testings were performed. The levels of tyrosine hydroxylase (TH) and macrophage antigen (MAC)-1 were determined with immunohistochemistry. The expression of iNOS and COX-2 was measured using RT PCR. RESULTS: In MPP(+)-treated rat mesencephalic cultures, 6-shogaol significantly increased the number of TH-IR neurons and suppressed TNF-α and NO levels. In C57/BL mice, treatment with 6-shogaol reversed MPTP-induced changes in motor coordination and bradykinesia. Furthermore, 6-shogaol reversed MPTP-induced reductions in TH-positive cell number in the substantia nigra pars compacta (SNpc) and TH-IR fiber intensity in stratum (ST). Moreover, 6-shogaol significantly inhibited the MPTP-induced microglial activation and increases in the levels of TNF-α, NO, iNOS, and COX-2 in both SNpc and ST. CONCLUSION: 6-Shogaol exerts neuroprotective effects on DA neurons in in vitro and in vivo PD models.

Sauchinone, a lignan from Saururus chinensis, protects human skin keratinocytes against ultraviolet B-induced photoaging by regulating the oxidative defense system.

Ultraviolet (UV) radiation from sunlight induces matrix metalloproteinase (MMP) expression, which are responsible for collagenous extracellular matrix proteins breakdown in skin, causing photoaging. Sauchinone is reported to have various bioactivity such as antioxidative, hepatoprotective, and anti-inflammatory effects. In the present study, we investigated the protective effect of sauchinone against UVB (50 mJ/cm(2))-induced photoaging in HaCaT human epidermal keratinocytes. Sauchinone, at 5-40 µM, significantly protected keratinocytes against UVB-induced damage as assessed by cell viability and toxicity assay. Additionally, sauchinone, at 20-40 µM, prevented the upregulation of MMP-1 proteins and reduction of type 1 collagen induced by UVB. Other assays revealed that, in keratinocytes, sauchinone decreased reactive oxygen species (ROS) production and increased glutathione levels and heme oxygenase-1. Sauchinone also inhibited UVB-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling pathways. These results demonstrated that sauchinone protects skin keratinocytes through inhibition of extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 MAPK signaling via upregulation of oxidative defense enzymes.

Repeated heat exposure impairs nigrostriatal dopaminergic neurons in mice.

Environmental heat stress is associated with physical stress responses, including changes in monoamines, protein expression, and neuronal circuits and damage to neurons in the brain. This study determined the effects of heat stress on the nigrostriatal dopaminergic system based on behavioral, histological, and neurochemical analyses. To evaluate behavioral changes after heat exposure, we subjected mice to the pole and open field tests. The data suggested that heat stress for 7 d significantly impaired movement. Then, we conducted a histological analysis using tyrosine hydroxylase (TH) immunoreactivity in the striatum and substantia nigra (SN). Heat stress induced a significant deficit in TH-positive fibers and cells after 14- and 21-d exposure, respectively. We also measured the striatal dopamine (DA), 4-hydroxy-3-methoxy-phenylacetic acid, and 3,4-dihydroxyphenylacetic acid levels. The data suggested that DA turnover rate increased with heat exposure in a time-dependent manner, resulting in the significant decrease of DA after 28 d. Moreover, the expression of heat shock protein 70 (HSP70) was increased in the mouse SN with up to 14-d heat exposure, but decreased after 21 d of the stress. And glucose-regulated protein 78 (GRP78) was gradually increased in the mouse SN with 28-d heat exposure. The caspase-3 activity was also increased after 14-d heat exposure. These findings are the first evidence that repeated heat stress impairs nigrostriatal dopaminergic neurons, motor function, and DA availability with changes of HSP70 and GRP78 expressions and caspase-3 activity in mice.

Sanguisorbae radix protects against 6-hydroxydopamine-induced neurotoxicity by regulating NADPH oxidase and NF-E2-related factor-2/heme oxygenase-1 expressions.

6-Hydroxydopamine (6-OHDA) produces neuronal cell damage by generating reactive oxygen species (ROS). The major mechanisms of protection against ROS-induced stress are inhibiting expression of ROS generating genes such as NADPH oxidase (NOX) and increasing expression of endogenous antioxidant genes such as heme oxygenase-1 (HO-1). This study investigated whether a standardized Sanguisorbae Radix extract (SRE), a medical herb commonly used in Asian traditional medicine, has a protective effect on 6-OHDA-induced cell toxicity by regulating ROS in SH-SY5Y cells. SRE at 10 and 50 µg/mL significantly reduced 6-OHDA-induced cell damage dose dependently in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and by Hoechst 33342 staining. SRE increased the B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X ratio and decreased cytochrome C release and caspase-3 activity. SRE also abolished 6-OHDA-induced ROS by inhibiting NOX expression and by inducing HO-1 expression via NF-E2-related factor-2 activation. Taken together, these results demonstrate that SRE has protective effects against 6-OHDA-induced cell death by regulating ROS in SH-SY5Y cells.

Changes in RBM47 expression based on the timing of melatonin administration and its effects on Nrf2 activity in the hippocampus.

Melatonin is an endogenous indoleamine that plays a significant role in various physiological processes, including the sleep-wake cycle, anxiety, immunity, and circadian rhythms. However, it is important to clarify that melatonin does not directly control circadian rhythms. Circadian rhythms are primarily synchronized by light, which acts on the suprachiasmatic nucleus (SCN) and subsequently regulates melatonin production. This light-mediated synchronization of circadian rhythms is essential for maintaining the alignment of the body with the light-dark cycle. In this study, we investigated the efficacy of melatonin administration during different times of the day or night and explored its neuroprotective effects. Furthermore, we aimed to apply these findings to rodent models of dementia, aging, and neuro-inflammation for potential therapeutic applications. Our study uncovered novel evidence suggesting the involvement of RNA-binding motif protein (RBM)-47 and Nrf2 in the signaling pathways associated with melatonin administration during both day and night. We examined the role of RBM47 in Nrf2 activity through siRNA or CRISPR-mediated knockdown experiments using hippocampal neuronal cells and lentivirus injections in mice. In 5xFAD/aging/neuroinflammatory mouse models, antioxidant effects were enhanced when melatonin was administered during the day compared to nighttime administration. Furthermore, mRNA analysis and molecular biology experiments revealed the differential expression of RBM47 depending on the timing of melatonin administration. These findings suggest that a decrease in RBM47 expression may improve the antioxidant defense system in the hippocampus. Consequently, administering melatonin during the day rather than at night may present a plausible therapeutic strategy as an antioxidant.