Oxidative stress mediates chemical hypoxia-induced injury and inflammation by activating NF-κb-COX-2 pathway in HaCaT cells

Advancements in incorporating metal ions onto the surface of biomedical titanium and its alloys via micro-arc oxidation: a research review

The incorporation of biologically active metallic elements into nano/micron-scale coatings through micro-arc oxidation (MAO) shows significant potential in enhancing the biological characteristics and functionality of titanium-based materials. By introducing diverse metal ions onto titanium implant surfaces, not only can their antibacterial, anti-inflammatory and corrosion resistance properties be heightened, but it also promotes vascular growth and facilitates the formation of new bone tissue. This review provides a thorough examination of recent advancements in this field, covering the characteristics of commonly used metal ions and their associated preparation parameters. It also highlights the diverse applications of specific metal ions in enhancing osteogenesis, angiogenesis, antibacterial efficacy, anti-inflammatory and corrosion resistance properties of titanium implants. Furthermore, the review discusses challenges faced and future prospects in this promising area of research. In conclusion, the synergistic approach of micro-arc oxidation and metal ion doping demonstrates substantial promise in advancing the effectiveness of biomedical titanium and its alloys, promising improved outcomes in medical implant applications.

The role of cellular crosstalk in the progression of diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common complications of diabetes, and its main manifestations are progressive proteinuria and abnormal renal function, which eventually develops end stage renal disease (ESRD). The pathogenesis of DN is complex and involves many signaling pathways and molecules, including metabolic disorders, genetic factors, oxidative stress, inflammation, and microcirculatory abnormalities strategies. With the development of medical experimental techniques, such as single-cell transcriptome sequencing and single-cell proteomics, the pathological alterations caused by kidney cell interactions have attracted more and more attention. Here, we reviewed the characteristics and related mechanisms of crosstalk among kidney cells podocytes, endothelial cells, mesangial cells, pericytes, and immune cells during the development and progression of DN and highlighted its potential therapeutic effects.

Priming with caffeic acid enhances the potential and survival ability of human adipose-derived stem cells to counteract hypoxia

The therapeutic effectiveness of stem cells after transplantation is hampered by the hypoxic milieu of chronic wounds. Prior research has established antioxidant priming as a thorough plan to improve stem cell performance. The purpose of this study was to ascertain how caffeic acid (CA) priming affected the ability of human adipose-derived stem cells (hASCs) to function under hypoxic stress. In order to study the cytoprotective properties of CA, hASCs were primed with CA in CoCl₂ hypoxic conditions. Microscopy was used to assess cell morphology, while XTT, Trypan Blue, X-gal, LDH, Live Dead, scratch wound healing, and ROS assays were used to analyze viability, senescence, cell death, proliferation, and reactive oxygen species prevalence in the cells. According to our findings, CA priming enhances hASCs' ability to survive and regenerate in a hypoxic microenvironment more effectively than untreated hASCs. Our in-vitro research suggested that pre-treatment with CA of hASCs could be a unique way to enhance their therapeutic efficacy and ability to survive in hypoxic microenvironments.

High-altitude Hypoxia Influences the Activities of the Drug-Metabolizing Enzyme CYP3A1 and the Pharmacokinetics of Four Cardiovascular System Drugs

(1) Background: High-altitude hypoxia has been shown to affect the pharmacokinetic properties of drugs. Although there is a high incidence of cardiovascular disease among individuals living in high-altitude areas, studies on the effect of high-altitude hypoxia on the pharmacokinetic properties of cardiovascular drugs are limited. (2) Methods: The aim of this study was to evaluate the pharmacokinetics of nifedipine, bosentan, simvastatin, sildenafil, and their respective main metabolites, dehydronifedipine, hydroxybosentan, simvastatin hydroxy acid, and N-desmethyl sildenafil, in rats exposed to high-altitude hypoxia. Additionally, the protein and mRNA expression of cytochrome P450 3A1 (CYP3A1), a drug-metabolizing enzyme, were examined. (3) Results: There were significant changes in the pharmacokinetic properties of the drugs in rats exposed to high-altitude hypoxia, as evidenced by an increase in the area under the curve (AUC) and the half-life (t_1/2z) and a decrease in total plasma clearance (CL_z/F). However, most of these changes were reversed when the rats returned to a normoxic environment. Additionally, there was a significant decrease in CYP3A1 expression in rats exposed to high-altitude hypoxia at both the protein and mRNA levels. (4) Conclusions: High-altitude hypoxia suppressed the metabolism of the drugs, indicating that the pharmacokinetics of the drugs should be re-examined, and the optimal dose should be reassessed in patients living in high-altitude areas.

Ameliorative effects of epigallocatechin-3-gallate nanoparticles on 2,4-dinitrochlorobenzene induced atopic dermatitis: A potential mechanism of inflammation-related necroptosis

Atopic dermatitis (AD) is a common autoimmune and chronic inflammatory cutaneous disease with a relapsing-remitting course. Necroptosis is a regulated necrotic cell death mediated by receptor-interacting protein 1 (RIP1), receptor-interacting protein 3 (RIP3), and mixed lineage kinase domain-like pseudokinase (MLKL), which is activated by tumor necrosis factor-α (TNF-α). However, the mechanism and the role of necroptosis have not been delineated in AD progression. (-)-Epigallocatechin-3-gallate (EGCG), the main biological activity of tea catechin, is well known for its beneficial effects in the treatment of skin diseases. Here, PEG-PLGA-EGCG nanoparticles (EGCG-NPs) were formulated to investigate the bioavailability of EGCG to rescue cellular injury following the inhibition of necroptosis after AD. 2,4-dinitrochlorobenzene (DNCB) was used to establish AD mouse models. As expected, topically applied EGCG-NPs elicited a significant amelioration of AD symptoms in skin lesions, including reductions in the ear and skin thickness, dermatitis score, and scratching behavior, which was accompanied by redox homeostasis restored early in the experiment. In addition, EGCG-NPs significantly decreased the expression of inflammatory cytokines like TNF-α, interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-6 (IL-6), and interleukin-17A (IL-17A) in a time-dependent manner than those of in AD group. As a result, the overexpression of RIP1, RIP3, and MLKL in the entire epidermis layers was dramatically blocked by EGCG-NPs, as well as the expression ofphosphorylated p38 (p-p38), extracellular signal-regulated kinase 1 (ERK1), and extracellular signal-regulated kinase 2 (ERK2). These findings promote that EGCG-NPs formulation represents a promising drug-delivery strategy for the treatment of AD by maintaining the balance of Th1/Th2 inflammation response and targeting necroptosis.

Cobalt (II) Chloride Regulates the Invasion and Survival of Brucella abortus 544 in RAW 264.7 Cells and B6 Mice

The effects of Cobalt (II) chloride (CoCl2) in the context of Brucella abortus (B. abortus) infection have not been evaluated so far. Firstly, we found that CoCl2 treatment inhibited the phagocytosis of B. abortus into RAW 264.7 cells. The inhibition of bacterial invasion was regulated by F-actin formation and associated with a reduction in the phosphorylation of ERK1/2 and HIF-1α expression. Secondly, the activation of trafficking regulators LAMP1, LAMP2, and lysosomal enzyme GLA at the transcriptional level activated immune responses, weakening the B. abortus growth at 4 h post-infection (pi). The silencing of HIF-1α increased bacterial survival at 24 h pi. At the same time, CoCl2 treatment showed a significant increase in the transcripts of lysosomal enzyme HEXB and cytokine TNF-α and an attenuation of the bacterial survival. Moreover, the enhancement at the protein level of HIF-1α was induced in the CoCl2 treatment at both 4 and 24 h pi. Finally, our results demonstrated that CoCl2 administration induced the production of serum cytokines IFN-γ and IL-6, which is accompanied by dampened Brucella proliferation in the spleen and liver of treated mice, and reduced the splenomegaly and hepatomegaly. Altogether, CoCl2 treatment contributed to host resistance against B. abortus infection with immunomodulatory effects.

Thermosensitive Hydrogel Incorporating Prussian Blue Nanoparticles Promotes Diabetic Wound Healing via ROS Scavenging and Mitochondrial Function Restoration

Diabetic foot ulcer is a serious complication in diabetes patients, imposing a serious physical and economic burden to patients and to the healthcare system as a whole. Oxidative stress is thought to be a key driver of the pathogenesis of such ulcers. However, no antioxidant drugs have received clinical approval to date, underscoring the need for the further development of such medications. Hydrogels can be applied directly to the wound site, wherein they function to prevent infection and maintain local moisture concentrations, in addition to serving as a reservoir for the delivery of a range of therapeutic compounds with the potential to expedite wound healing in a synergistic manner. Herein, we synthesized Prussian blue nanoparticles (PBNPs) capable of efficiently scavenging reactive oxygen species (ROS) owing to their ability to mimic the activity of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD). In the context of in vitro oxidative stress, these PBNPs were able to protect against cytotoxicity, protect mitochondria from oxidative stress-related damage, and restore nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathway activity. To expand on these results in an in vivo context, we prepared a thermosensitive poly (d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA) hydrogel (PLEL)-based wound dressing in which PBNPs had been homogenously incorporated, and we then used this dressing as a platform for controlled PBNP release. The resultant PBNPs@PLEL wound dressing was able to improve diabetic wound healing, decrease ROS production, promote angiogenesis, and reduce pro-inflammatory interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels within diabetic wounds. Overall, our results suggest that this PBNPs@PLEL platform holds great promise as a treatment for diabetic foot ulcers.

Liquiritin reduces lipopolysaccharide-aroused HaCaT cell inflammation damage via regulation of microRNA-31/MyD88

BACKGROUND

Pressure ulcers are a common issue for people who have limited mobility. This study tested the impact of liquiritin on human keratinocyte HaCaT cell inflammatory damage aroused by lipopolysaccharide (LPS).

METHODS

HaCaT cells were underwent LPS and/or liquiritin incubation. Cell viability, apoptosis and inflammatory molecules interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and cyclooxygenase-2 (Cox-2) expressions, along with nuclear factor kappa B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways activities were tested by MTT assay, Guava Nexin assay, ELISA and western blotting, respectively. qRT-PCR was done for measuring microRNA-31 (miR-31) expression. miR-31 inhibitor was transfected to silence miR-31. Animal pressure ulcers was established on the dorsal skin of adult rats. The effects of liquiritin on wound healing were analyzed by measuring wound closure rates.

RESULTS

LPS aroused HaCaT cell inflammatory damage, as evidenced by the decrease of cell viability, increase of cell apoptosis and enhanced expressions of IL-6, TNF-α and Cox-2. Liquiritin protected HaCaT cells against LPS-aroused inflammatory damage through increasing cell viability, decreasing cell apoptosis, and reducing IL-6, TNF-α and Cox-2 expressions. Liquiritin attenuated the LPS-aroused NF-κB and JNK pathways activation in HaCaT cells. Rat pressure ulcers model also confirmed that liquiritin promoted wound healing. In mechanism, miR-31 expression was boosted by liquiritin in HaCaT cells. Silencing miR-31 weakened the impacts of liquiritin on LPS-irritated HaCaT cells. Myeloid differentiation factor 88 (MyD88) was a target of miR-31 in HaCaT cells.

CONCLUSION

This research affirmed the beneficial impact of liquiritin on pressure ulcers. Liquiritin reduced LPS-aroused HaCaT cell inflammatory damage might be implemented via raising miR-31 expression, lowering MyD88 expression, and repressing NF-κB and JNK pathways.

Dermal exposure to cobalt studied in vitro in keratinocytes - effects of cobalt exposure on inflammasome activated cytokines, and mRNA response

BACKGROUND

Cobalt is a dermal sensitizer, and keratinocytes respond to cobalt exposure by releasing proinflammatory mediators, regulating the immune response.

OBJECTIVE

To determine the effect of cobalt on the inflammasome associated cytokine- and gene expression in cultured human keratinocytes (HaCaT). Cultivation in low- or high calcium conditions model separate differentiation states of keratinocytes in the skin.

METHOD

HaCaT cells in two different states of differentiation were exposed to cobalt chloride and caspase-1 activity as well as the production of IL-1β, IL-18 and gene expression of IL1B, IL18, NLRP3, CASP1, and PYCARD was quantified.

RESULTS

High cobalt chloride exposure mediated significant increase in caspase-1 activity, cytokine levels, and IL1B and NLRP3 expression with a corresponding regulatory decrease for CASP1 and PYCARD expression. No difference between high- and low calcium culturing conditions modelling differentiation states was detected.

CONCLUSIONS

Our data suggest that HaCaT cells respond with inflammmasome associated activity upon cobalt exposure in a concentration-dependent manner. These mechanisms could be of importance for the understanding of the pathophysiology behind allergic sensitization to dermal cobalt exposure.

Woodsmoke Extracts Cross-Link Proteins and Induce Cornified Envelope Formation without Stimulating Keratinocyte Terminal Differentiation

Air pollution poses a serious risk to human health. To help understand the contribution of smoke from wood burning to the harmfulness of air pollution toward the skin, we studied the effects of liquid smoke, aqueous extracts of wood smoke condensate, a commercially available food flavor additive, in cultured keratinocytes. We report that liquid smoke can react with and cross-link keratinocyte cellular proteins, leading to abnormal cross-linked envelope formation. Instead of inducing genes ordinarily involved in terminal differentiation, liquid smoke induced expression of genes associated with stress responses. When transglutaminase activity was inhibited, liquid smoke still promoted protein cross-linking and envelope formation in keratinocytes. This phenomenon likely results from oxidative stress and protein adducts from aldehydes as either preloading the cells with N-acetylcysteine or reducing the aldehyde content of liquid smoke decreased its ability to promote protein cross-linking and envelope formation. Finally, liquid smoke-induced envelopes were found to have elevated protein content, suggesting oxidative cross-linking and formation of protein adducts might impair barrier function by inducing abnormal incorporation of cellular proteins into envelopes. Since the cross-linked protein envelope provides structural stability to the stratum corneum and serves as a scaffold for the organization of the corneocyte lipid envelope (hydrophobic barrier to the environment), these findings provide new insight into the mechanism by which pro-oxidative air pollutants can impair epidermal function.

Dose- and time-dependent changes in viability and IL-6, CXCL8 and CCL2 production by HaCaT-cells exposed to cobalt. Effects of high and low calcium growth conditions

Background

Sensitization requires exposure to an allergen with subsequent production of a “danger “signal. In the skin, keratinocytes are the main producers of these signals.

Objective

To compare dose- and time-effects of cobalt on the viability of and cytokine release from HaCaT cells cultured at low or high calcium.

Method

To model two separate states of differentiation of keratinocytes, HaCaT cells were cultured under low or high calcium conditions. HaCaT were exposed to different concentrations of cobalt chloride (10 μm to 5 mM) over time (30 minutes– 48 hours). Cell viability was measured with the Cell-Titer Blue Viability assay. Cytokine production was measured using a bead-based immunoassay and flow cytometry. Gene expression was quantified using qPCR. Data was analyzed by ANOVA and linear mixed model.

Results

Viability of the cells was dose- and time-dependent. A linear mixed statistical model showed that cobalt exposure induces increase in IL-6, CXCL8 and CCL2 production over time and whereas increase of IL-6 and a decrease of CCL2 was associated with increasing cobalt chloride concentrations. When comparing the cells incubated under high and low calcium conditions, the more differentiated cells in the high concentration were found to exert a stronger response in terms of IL-6 release.

Conclusions

Our data suggest that cobalt chloride triggered an alarm system in HaCaT cells, and proinflammatory cytokines/chemokines were secreted in a dose- and time-dependent manner. When high and low calcium incubations were compared, the difference was seen only for IL-6. These findings indicate that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis.

Haplopine Ameliorates 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis-Like Skin Lesions in Mice and TNF-α/IFN-γ-Induced Inflammation in Human Keratinocyte

This study aimed to investigate the anti-inflammatory, antioxidant, and anti-atopic dermatitis (AD) effects of haplopine, which is one of the active components in D. dasycarpus. Haplopine (12.5 and 25 μM) inhibited the mRNA expressions of inflammatory cytokines IL-6, TSLP, GM-CSF, and G-CSF and the protein expressions of IL-6 and GM-CSF in TNF-α/INF-γ-stimulated HaCaT cells. In H₂O₂-induced Jukat T cells, haplopine (25 and 50 μM) suppressed the productions of proinflammatory cytokines (IL-4, IL-13, and COX-2) and increased the mRNA and protein expressions of oxidative stress defense enzymes (SOD, CAT, and HO-1) in a concentration-dependent manner. In vivo, haplopine significantly attenuated the development of AD symptoms in 2,4-dinitrochlorobenzene (DNCB)-stimulated Balb/c mice, as evidenced by reduced clinical dermatitis scores, skin thickness measurements, mast cell infiltration, and serum IgE concentrations. These findings demonstrate that haplopine should be considered a novel anti-atopic agent with the potential to treat AD.

3-B-RUT, a derivative of RUT, protected against alcohol-induced liver injury by attenuating inflammation and oxidative stress

Alcoholic liver disease (ALD) is the most common chronic liver disease worldwide. Currently, there is no definitive treatment for alcohol-induced liver injury (ALI). Inflammatory response and oxidative stress play a crucial role in ALI. Cyclooxygenase 2 (COX-2) can be induced by inflammation and it has been reported that the enhanced expression of COX-2 in alcoholic liver injury. Rutaecarpine (RUT) was extracted from evodia rutaecarpa. RUT has a wide range of pharmacological activities. In order to increase its anti-inflammatory activity, our group introduced sulfonyl group to synthesized the 3-[2-(trifluoromethoxy)benzenesulfonamide]-rutaecarpine (3-B-RUT). In this study, we explored the protective effect of 3-B-RUT on alcoholic liver injury in vivo and in vitro and preliminarily explore its mechanism. Mice ALI model was established according to the chronic-plus-binge ethanol model. Results showed that 3-B-RUT (20 μg/kg) attenuated alcohol-induced liver injury and suppressed liver inflammation and oxidative stress, and the effect was comparable to RUT (20 mg/kg). In vitro results are consistent with in vivo results. Mechanistically, the 3-B-RUT might suppress inflammatory response and oxidative stress by regulating activation of NF-κB/COX-2 pathway. In summary, 3-B-RUT, a derivative of RUT, may be a promising clinical candidate for ALI treatment.

Role of microRNAs in Pressure Ulcer Immune Response, Pathogenesis, and Treatment

Pressure ulcers are preventable, yet highly prevalent, chronic wounds that have significant patient morbidity and high healthcare costs. Like other chronic wounds, they are characterized by impaired wound healing due to dysregulated immune processes. This review will highlight key biochemical pathways in the pathogenesis of pressure injury and how this signaling leads to impaired wound healing. This review is the first to comprehensively describe the current literature on microRNA (miRNA, miR) regulation of pressure ulcer pathophysiology.

Endothelial cells secreted endothelin-1 augments diabetic nephropathy via inducing extracellular matrix accumulation of mesangial cells in ETBR-/- mice

Endothelin B receptor (ETBR) deficiency may contribute to the progression of diabetic nephropathy (DN) in a streptozotocin (STZ) model, but the underlying mechanism is not fully revealed. In this study, STZ-diabetic ETBR^-/- mice was characterized by increased serum creatinine and urinary albumin, enhanced glomerulosclerosis, and upregulated ET-1 expression compared with STZ-diabetic WT mice. In vitro, HG conditioned media (CM) of ETBR^-/- GENs promoted mesangial cell proliferation and upregulated ECM-related proteins, and ET-1 knockout in GENs or inhibition of ET-1/ETAR in mesangial cell suppressed mesangial cell proliferation and collagen IV formation. In addition, ET-1 was over-expressed in ETBR^-/- GENs and was regulated by NF-kapapB pathway. ET-1/ETBR suppressed NF-kappaB to modulate ET-1 in GENs. Furthermore, ET-1/ETAR promoted RhoA/ROCK pathway in mesangial cells, and accelerated mesangial cell proliferation and ECM accumulation. Finally, in vivo experiments proved inhibition of NF-kappaB pathway ameliorated DN in ETBR^-/- mice. These results suggest that in HG-exposed ETBR^-/- GENs, suppression of ET-1 binding to ETBR activated NF-kappaB pathway, thus to secrete large amount of ET-1. Due to the communication between GENs and mesangial cells in diabetes, ET-1 binding to ETAR in mesangial cell promoted RhoA/ROCK pathway, thus to accelerate mesangial cell proliferation and ECM accumulation.

Is Hydrogen Sulfide a Concern During Treatment of Lung Adenocarcinoma With Ammonium Tetrathiomolybdate?

Ammonium tetrathiomolybdate (ATTM) has been used in breast cancer therapy for copper chelation, as elevated copper promotes tumor growth. ATTM is also an identified H₂S donor and endogenous H₂S facilitates VitB₁₂-induced S-adenosylmethionine (SAM) generation, which have been confirmed in m⁶A methylation and lung cancer development. The m⁶A modification was recently shown to participate in lung adenocarcinoma (LUAD) progression. These conflicting analyses of ATTM's anticancer vs. H₂S's carcinogenesis suggest that H₂S should not be ignored during LUAD's treatment with ATTM. This study was aimed to explore ATTM's effects on LUAD cells and mechanisms associated with H₂S and m⁶A. It was found that treatment with ATTM inhibited cell growth at high concentrations, while enhanced cell growth at low concentrations in three LUAD cell lines (A549, HCC827, and PC9). However, another copper chelator triethylenetetramine, without H₂S releasing activity, was not found to induce cell growth. Low ATTM concentrations also elevated m⁶A content in A549 cells. Analysis of differentially expressed genes in TCGA cohort indicated that m⁶A writer METTL3 and reader YTHDF1 were upregulated while eraser FTO was downregulated in LUAD tissues, consistent with the findings of protein expression in patient tissues. ATTM treatment of A549 cells significantly increased METTL3/14 and YTHDF1 while decreased FTO expression. Furthermore, inhibition of m⁶A with shMETTL3 RNA significantly attenuated eukaryotic translation initiation factor (eIF) expressions in A549 cells. Correlation analysis indicated that small nuclear ribonucleic protein PRPF6 was positively expressed with YTHDF1 in LUAD tissues. Knockdown of YTHDF1 partially blocked both basal and ATTM-induced PRPF6 expression, as well as A549 cell growth. Lastly, ATTM treatment not only raised intracellular H₂S content but also upregulated H₂S-producing enzymes. Exogenous H₂S application mimicked ATTM's aforementioned effects, but the effects could be weakened by zinc-induced H₂S scavenging. Collectively, H₂S impedes ATTM-induced anticancer effects through YTHDF1-dependent PRPF6 m⁶A methylation in lung adenocarcinoma cells.

Rutin abrogates manganese-Induced striatal and hippocampal toxicity via inhibition of iron depletion, oxidative stress, inflammation and suppressing the NF-κB signaling pathway

Excess exposure to Manganese (Mn) promotes oxidative stress and neuro-inflammation. Rutin (RUT) has been found to exhibit both anti-oxidative stress and anti-inflammatory properties. This study aimed to investigate the effects of RUT on Mn accumulation, endogenous iron (Fe) depletion, oxidative stress, inflammation and nuclear factor kappa B (NF-κB) signaling pathways in the hippocampus and striatum of Mn - induced rats. Rats were treated with 30 mg/kg Mn body weight alone or orally co-treated by gavage with RUT at 50 and at 100 mg/kg body weight for 35 consecutive days. Thereafter, we investigated Mn and endogenous Fe levels, acetylcholinesterase activity, oxidative stress markers, pro-inflammatory cytokines and nuclear factor kappa B (NF-κB) in the hippocampus and striatum of rats. The results indicate that Mn induced Mn - accumulation, Fe depletion, oxidative stress, inflammation and the activation of acetylcholinesterase activity and NF-κB signaling pathways in the hippocampus and striatum of the rats. However, RUT attenuated Fe depletion, oxidative stress and inflammation and suppressed acetylcholinesterase activity and NF-κB pathway via downstream regulations of tumor necrosis factor alpha, interleukin I beta and interleukin 6. Taken together, our present study demonstrates that RUT abrogates Mn - induced striatal and hippocampal toxicity via inhibition of Fe depletion, oxidative stress, inflammation and suppressing the NF-κB signaling pathways. Our results indicate that RUT may be of use as a neuroprotective agent against Mn - induced neuronal toxicity.

Antiphotoaging and Antimelanogenic Effects of Penthorum chinense Pursh Ethanol Extract due to Antioxidant- and Autophagy-Inducing Properties

Ethnopharmacological Relevance. Penthorum chinense Pursh (Penthoraceae) is a traditional herbal plant that has been used in China for the treatment of jaundice, cholecystitis, edema, and infectious hepatitis. In addition, the Korea Medicinal Plant Dictionary states that Penthorum chinense Pursh can be used to treat contusions and skin bruises by improving blood flow. Recent studies have shown that Penthorum chinense Pursh ethanol extract (Pc-EE) exhibits strong antioxidant effects. In this study, we examined the effects of Pc-EE on UVB-induced or H₂O₂-induced oxidative stress, as well as its antimelanogenic properties. Cell viability, matrix metalloproteinase (MMP) expression, cyclooxygenease-2 (COX-2), and interleukin-6 (IL-6) expression and moisturizing factors were investigated in keratinocytes. Collagen synthesis induction was measured in HEK293T cells. For melanogenesis, the effects of Pc-EE on melanin content and tyrosinase activity were measured. Additionally, the antimelanogenic- and autophagy-inducing activities of Pc-EE were examined using immunoblotting and confocal microscopy. Pc-EE protected HaCaT cells against death from UVB irradiation- or H₂O₂-induced oxidative stress. Pc-EE increased the promoter activity of the type 1 procollagen gene Col1A1 and decreased the expression of MMPs, COX-2, IL-6, and hyaluronidase induced by UVB irradiation- or H₂O₂-induced oxidative stress. Pc-EE showed a strong antioxidant effect in the DPPH assay. In α-melanocyte-stimulating hormone- (α-MSH-) stimulated B16F10 cells, Pc-EE reduced melanin production, decreased tyrosinase expression and microphthalmia-associated transcription factor (MITF) protein levels, and decreased the phosphorylation levels of p38 and JNK. In HEK293T cells, Pc-EE promoted the expression of GFP-LC3B. In B16F10 cells, the LC3B and melanin contents were reduced by Pc-EE and were restored by the autophagy inhibitor 3-methyladenine (3-MA). These results suggest that Pc-EE can be used as a skin protection agent due to its antiapoptotic, antiaging, anti-inflammatory, and antimelanogenic properties.

Reduced AMPK activation and increased HCAR activation drive anti-inflammatory response and neuroprotection in glaucoma

Background

Glaucoma is a chronic degenerative disease for which inflammation is considered to play a pivotal role in the pathogenesis and progression. In this study, we examined the impact of a ketogenic diet on the inflammation evident in glaucoma as a follow-up to a recent set of experiments in which we determined that a ketogenic diet protected retinal ganglion cell structure and function.

Methods

Both sexes of DBA/2J (D2) mice were placed on a ketogenic diet (keto) or standard rodent chow (untreated) for 8 weeks beginning at 9 months of age. DBA/2J-Gpnmb⁺ (D2G) mice were also used as a non-pathological genetic control for the D2 mice. Retina and optic nerve (ON) tissues were micro-dissected and used for the analysis of microglia activation, expression of pro- and anti-inflammatory molecules, and lactate- or ketone-mediated anti-inflammatory signaling. Data were analyzed by immunohistochemistry, quantitative RT-PCR, ELISA, western blot, and capillary tube-based electrophoresis techniques.

Results

Microglia activation was observed in D2 retina and ON as documented by intense microglial-specific Iba1 immunolabeling of rounded-up and enlarged microglia. Ketogenic diet treatment reduced Iba1 expression and the activated microglial phenotype. We detected low energy-induced AMP-activated protein kinase (AMPK) phosphorylation in D2 retina and ON that triggered NF-κB p65 signaling through its nuclear translocation. NF-κB induced pro-inflammatory TNF-α, IL-6, and NOS2 expression in D2 retina and ON. However, treatment with the ketogenic diet reduced AMPK phosphorylation, NF-κB p65 nuclear translocation, and expression of pro-inflammatory molecules. The ketogenic diet also induced expression of anti-inflammatory agents Il-4 and Arginase-1 in D2 retina and ON. Increased expression of hydroxycarboxylic acid receptor 1 (HCAR1) after ketogenic diet treatment was observed. HCAR1 stimulation by lactate or ketones from the ketogenic diet reduced inflammasome formation, as shown by reduced mRNA and protein expression of NLRP3 and IL-1β. We also detected increased levels of Arrestin β-2 protein, an adapter protein required for HCAR1 signaling.

Conclusion

Our data demonstrate that the AMPK activation apparent in the glaucomatous retina and ON triggers NF-κB signaling and consequently induces a pro-inflammatory response. The ketogenic diet resolves energy demand and ameliorates the inflammation by inhibition of AMPK activation and stimulation of HCAR1-ARRB2 signaling that inhibits NLRP3 inflammasome-mediated inflammation. Thus, these findings depict a neuroprotective mechanism of the ketogenic diet in controlling inflammation and suggest potential therapeutic targets for inflammatory neurodegenerative diseases, including glaucoma.

Suppression of LRRC19 promotes cutaneous wound healing in pressure ulcers in mice

The ischemia-reperfusion (I/R) induced skin lesion has been identified as primary cause of pressure ulcer. Better understanding of the mechanism is required for new therapy development. Leucine rich repeat containing protein 19 (LRRC19) is a recently discovered transmembrane protein containing leucine-rich repeats and plays a role in immune response. To investigate the role of LRRC19 in pressure ulcers, mouse ulcer model was established with two cycles of I/R. The expression of LRRC19 was assessed during injury. siRNA mediated LRRC19 downregulation was applied to investigate the disease severity, immune cell infiltration and pro-inflammatory cytokines production. The primary skin fibroblasts were stimulated with IL-1β to dissect the molecular mechanism. LRRC19 was readily induced in I/R induced lesion site in a pattern mimicking the disease progress as measured by wound area. Knockdown of LRRC19 by siRNA significantly alleviated the disease severity and attenuated immune cell infiltration and pro-inflammatory cytokines production. In primary skin fibroblast model, siRNA knockdown of LRRC19 suppressed IL-1β mediated NFκB activation and its downstream cytokines production. LRRC19 was a novel factor for I/R-induced tissue damage by promoting NFκB dependent pro-inflammatory response. Our results supported that LRRC19 could be a potential therapeutic target for pressure ulcers.

Fish Scale Collagen Peptides Protect against CoCl2/TNF-α-Induced Cytotoxicity and Inflammation via Inhibition of ROS, MAPK, and NF-κB Pathways in HaCaT Cells

Skin diseases associated with inflammation or oxidative stress represent the most common problem in dermatology. The present study demonstrates that fish scale collagen peptides (FSCP) protect against CoCl₂-induced cytotoxicity and TNF-α-induced inflammatory responses in human HaCaT keratinocyte cells. Our study is the first to report that FSCP increase cell viability and ameliorate oxidative injury in HaCaT cells through mechanisms mediated by the downregulation of key proinflammatory cytokines, namely, TNF-α, IL-1β, IL-8, and iNOS. FSCP also prevent cell apoptosis by repressing Bax expression, caspase-3 activity, and cytochrome c release and by upregulating Bcl-2 protein levels in CoCl₂- or TNF-α-stimulated HaCaT cells. In addition, the inhibitory effects of FSCP on cytotoxicity and the induction of proinflammatory cytokine expression were found to be associated with suppression of the ROS, MAPK (p38/MAPK, ERK, and JNK), and NF-κB signaling pathways. Taken together, our data suggest that FSCP are useful as immunomodulatory agents in inflammatory or immune-mediated skin diseases. Furthermore, our results provide new insights into the potential therapeutic use of FSCP in the prevention and treatment of various oxidative- or inflammatory stress-related inflammation and injuries.

Inhibition of Methylglyoxal-Induced AGEs/RAGE Expression Contributes to Dermal Protection by N-Acetyl-L-Cysteine

BACKGROUND/AIM

Accumulation of advanced glycation end products (AGEs) is a major cause of diabetes mellitus (DM) skin complications. Methylglyoxal (MGO), a reactive dicarbonyl compound, is a crucial intermediate of AGEs generation. N-acetyl-L-cysteine (NAC), an active ingredient of some medicines, can induce endogenous GSH and hydrogen sulfide generation, and set off a condensation reaction with MGO. However, there is rare evidence to show NAC can alleviate DM-induced skin injury through inhibition of AGEs generation or toxicity. The present study aimed to observe the effects of NAC on MGO-induced inflammatory injury and investigate the roles of AGEs and its receptor (RAGE) in NAC's dermal protection in human HaCaT keratinocytes.

METHODS

The cells were exposed to MGO to simulate a high MGO status in diabetic blood or tissues. The content of AGEs in serum or cell medium was measured with ELISA. The protective effects of NAC against MGO-induce injury were evaluated by administration before MGO one hour, in virtue of cell viability, mitochondrial membrane potential, inflammation reaction, nuclear factor (NF)-κB activation, matrix metalloproteinase (MMP)-9 expression, as well as cellular behavioral function.

RESULTS

We found the AGEs levels of patients with DM were elevated comparing with healthy volunteers. The in vitro AGEs generation was also able to be enhanced by the exposure of HaCaT cells to MGO, which reduced dose-dependently cellular viability, damaged mitochondrial function, triggered secretion of interleukin (IL)-6 and IL-8, activated NF-κB and upregulated MMP-9 expression. Furthermore, the exposure caused cellular adhesion and migration dysfunction, as well as collagen type I inhibition. Importantly, before the exposure to MGO, the preconditioning with NAC significantly attenuated MGO-induced AGEs generation, improved cellular viability and mitochondrial function, partially reversed the overexpression of proinflammatory factors and MMP-9, as well as the activation of NF-κB. Lastly, NAC blocked MGO-induced RAGE upregulation, and inhibition of RAGE with its neutralizing antibody significantly alleviated MGO-induced NF-κB activation, MMP-9 upregulation and inflammatory injury in HaCaT cells.

CONCLUSION

The present work indicates the administration of NAC can prevent MGO-induced dermal inflammatory injury through inhibition of AGEs/RAGE signal, which may provide a basal support for the treatment of diabetic skin complications with NAC-containing medicines in the future.

Intermittent Hypoxia and Unsaturated Aldehydes: Effects on Oral Epithelial Wound Healing

Obstructive sleep apnea (OSA) is a highly prevalent sleep breathing disorder characterized by intermittent hypoxia (IH), leading to blood hypoxemia, hypercapnia, and sleep fragmentation. Studies on the effects of OSA on oral epithelial tissue healing are limited. Smoking is considered a risk factor for OSA through the exposure to chemically active toxins, present in the smoke. Acrolein is the most chemically active unsaturated aldehyde, impairing a variety of biological processes. The aim of this study was to determine the effect of IH on oral epithelial tissue healing, with and without acrolein. HaCaT cells were wounded by a cross-scratch made in the cell cultures, considered as time zero. Then, cells were exposed to 28 IH cycles (5-20% oxygen) during 12 h using the BioSpherix OxyCycler-C42 system. Control cells were maintained in normoxic conditions or in sustained hypoxia (SH) (5% oxygen) for the same durations, after which all cells were maintained for additional 12 h in normoxia. The migrating abilities of cells were measured after 24 h by calculating the percent of the residual cross-scratch area. In parallel experiments, 25 μM acrolein were added to each treatment. We found that the scratch closure was the slowest under IH. After 24 h, the residual scratch area in the IH treated cells was 29.5 ± 13.4% of the initial area, while in normoxia and SH it was 9.2 ± 5.8% and 10.3 ± 11.3%, respectively (p < 0.01 for both vs. IH). Adding acrolein further attenuated the migratory ability in IH as compared to normoxia and SH. We conclude that IH delays the healing process of oral epithelial tissue by slowing the cells' migratory abilities. The healing might be further attenuated by chemically active unsaturated aldehydes such as acrolein.

Controls of Nuclear Factor-Kappa B Signaling Activity by 5'-AMP-Activated Protein Kinase Activation With Examples in Human Bladder Cancer Cells

Generally, both lipopolysaccharide (LPS)- and hypoxia-induced nuclear factor kappa B (NF-κB) effects are alleviated through differential posttranslational modification of NF-κB phosphorylation after pretreatment with 5´-AMP-activated protein kinase (AMPK) activators such as 5´-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or the hypoglycemic agent metformin. We found that AICAR or metformin acts as a regulator of LPS/NF-κB-or hypoxia/NF-κB-mediated cyclooxygenase induction by an AMPK-dependent mechanism with interactions between p65-NF-κB phosphorylation and acetylation, including in a human bladder cancer cell line (T24). In summary, we highlighted the regulatory interactions of AMPK activity on NF-κB induction, particularly in posttranslational phosphorylation and acetylation of NF-κB under inflammatory conditions or hypoxia environment.

Antioxidant tert-butylhydroquinone ameliorates arsenic-induced intracellular damages and apoptosis through induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes

Human skin is a known target site of inorganic arsenic with effects ranging from hyperkeratosis to dermal malignancies. Tert-butylhydroquinone (tBHQ), approved food-grade phenolic antioxidant, is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at the protective effects of tBHQ on arsenic-induced cytotoxicity and apoptosis in human keratinocytes. Our results demonstrated that tBHQ antagonized arsenic-induced decrease of cell viability, generation of reactive oxygen species (ROS) and lipid peroxidation, as well as reduction of antioxidative enzymes superoxide dismutase (SOD) and catalase (CAT) activities. We also found that tBHQ relieved the G2/M phase arrest by arsenic exposure, which was associated with altering the expression of cell cycle regulators cyclin D1 and CDK4. tBHQ treatment further reduced the numbers of arsenic-induced mitochondrial-mediated apoptotic cells, which occurred concomitantly with the effective recovery of mitochondrial membrane potential (ΔΨm) depolarization, the release of cytochrome c releasing from the mitochondrial as well as the survival signal related factor caspase 3 activation. Our experiments then confirmed that tBHQ activated nuclear factor E2-related factor 2 (NRF2) pathway by increasing NRF2 protein in both nucleus and cytoplasm and upregulating NRF2 downstream targets

NAD(P)H

quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). More interestingly, arsenic-induced decrease of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) and increase of pro-apoptotic factor Bcl-2-associated X protein (Bax) could all be reversed by tBHQ pretreatment. These results suggested together that tBHQ could ameliorate arsenic-induced cytotoxicity and apoptosis, which might be linked with the induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes.

Red Light Modulates Ultraviolet-Induced Gene Expression in the Epidermis of Hairless Mice

OBJECTIVE

The purpose of this study was to investigate whether low-level light therapy (LLLT) was capable of modulating expression of ultraviolet (UV) light-responsive genes in vivo.

MATERIALS AND METHODS

The effects of 670 nm light-emitting diode (LED) array irradiation were investigated in a hairless SHK-1 mouse epidermis model. Mice were given a single dose of UVA/UVB light, or three doses of red light (670 nm @ 8 mW/cm(2) x 312 sec, 2.5 J/cm(2) per session) spread over 24 h along with combinations of pre- and post-UV treatment with red light. Levels of 14 UV-responsive mRNAs were quantified 24 h after UV irradiation by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

The transcription of mRNAs encoding for cluster of differentiation molecule 11b (CD11b) (p < 0.05) and interferon (IFN)-γ (p < 0.012) increased after irradiation with red light alone, whereas expression level of cyclooxygenase (COX)-2 (p < 0.02) was downregulated. Genes unresponsive to UV did not change their expression levels after exposure to red light either. Pretreatment with red light significantly modified response of Fos to UV exposure (p < 0.01). A synergy of UV and post-treatment with red light in reducing the transcription levels of CD11b (p < 0.05) and inducible nitric oxide synthase (iNOS) (p < 0.05) was observed.

CONCLUSIONS

This is an initial observation that in mouse red light LLLT more often than not causes opposite gene expression changes or reduces those caused by moderate UVA-UVB irradiation.

Cynaropicrin attenuates UVB-induced oxidative stress via the AhR-Nrf2-Nqo1 pathway

Due to its antioxidant and anti-inflammatory activities, artichoke (Cynara scolymus) has been used as folk medicine to treat various diseases. Cynaropicrin (Cyn), a sesquiterpene lactone, is the major bioactive phytochemical in the artichoke; however, its pharmacological mechanism remains unknown. Because some phytochemicals exert their antioxidant activity by activating aryl hydrocarbon receptor (AhR), leading to subsequent induction of the antioxidant pathway including nuclear factor E2-related factor 2 (Nrf2) and

NAD(P)H

quinone oxidoreductase 1 (Nqo1), we investigated whether Cyn also activates the AhR-Nrf2-Nqo1 pathway. Cyn indeed induced the activation (nuclear translocation) of AhR, leading to nuclear translocation of Nrf2 and dose-dependent upregulation of Nrf2 and Nqo1 mRNAs in human keratinocytes. The Cyn-induced AhR-Nrf2-Nqo1 activation was AhR- and Nrf2-dependent, as demonstrated by the observation that it was absent in keratinocytes transfected by siRNA against either AhR or Nrf2. In accordance with these findings, Cyn actively inhibited generation of reactive oxygen species from keratinocytes irradiated with ultraviolet B (UVB) in a Nrf2-dependent manner. Cyn also inhibited the production of proinflammatory cytokines such as interleukin 6 and tumor necrosis factor-α from UVB-treated keratinocytes. Our findings demonstrate that Cyn is a potent activator of the AhR-Nrf2-Nqo1 pathway, and could therefore be applied to prevention of UVB-induced photo aging.

Activation of Protein C in Human Trophoblasts in Culture and Downregulation of Trophoblast Endothelial Protein C Receptor by TNF-α

In mice, trophoblasts are equipped with a potent anticoagulant mechanism, the protein C pathway. In human placenta, no functional studies of the protein C pathway are available. Human first-trimester trophoblasts (CK(++) HLA-G(+/-) Vim(-)) were isolated and kept in culture for a maximum of 48 hours. Activation of protein C on trophoblasts was at least as efficient as in endothelial cells (4.43 × 10 (-) (7) nmol/L/min/cell). Endothelial protein C receptor (EPCR) was expressed in syncytiotrophoblasts and extravillous trophoblasts. Downregulation of the messenger RNA of trophoblast EPCR occurred when trophoblasts were challenged with tumor necrosis factor α, and it could be prevented by unfractionated heparin but not by low-molecular-weight heparin at therapeutic doses. In conclusion, there is a functional protein C pathway on human first-trimester trophoblasts which can be modulated by inflammation. This finding has implications for the pathogenesis and prevention of placenta-mediated obstetric complications.

Effects of cobalt chloride on phenotypes of normal human saphenous vein smooth muscle cells

To explore the cellular adaptations and responses to hypoxia in normal human saphenous vein smooth muscle cells (SMCs) and presume what roles phenotypic modulation of normal human saphenous vein SMCs would play in varicose vein of lower extremity, we used cobalt chloride (CoCl2), a hypoxia mimetic, to treat normal human saphenous vein SMCs in vitro. The proliferating ability of cells exposed to serial dilutions of CoCl2 (0, 200, 300, 400 and 500 μM) at 24 h, 48 h and 72 h respectively was detected by MTT assay. Wound healing assay was used to observe the migrating ability of cells under CoCl2 (200 μM) treatment for 8 days continuously. Hoechst 33258 stain was used to determine whether hypoxia induced by CoCl2 could cause apoptosis of normal human saphenous vein SMCs. We found that CoCl2 enhanced the proliferation and inhibited the migration of normal human saphenous vein SMCs. The apparent morphous of normal human saphenous vein SMCs under chronic CoCl2 treatment was significantly changed compared to no CoCl2 treated control, but this process did not relate to cell apoptosis. To conclude, our results support the concept that the phenotypes of normal human saphenous vein SMCs could be influenced by hypoxia stimulus. Cellular structural and functional changes under chronic hypoxia in normal human saphenous vein SMCs might play important roles in the development of varicose veins of lower extremity.

The role of air pollutants in atopic dermatitis

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease and a growing health concern, especially in children, because of its high prevalence and associated low quality of life. Genetic predisposition, environmental triggers, or interactions between them contribute to the pathophysiology of AD. Therefore, it is very important to identify and control risk factors from the environment in susceptible subjects for successful treatment and prevention. Both indoor and outdoor air pollution, which are of increasing concern with urbanization, are well-known environmental risk factors for asthma, whereas there is relatively little evidence in AD. This review highlights epidemiologic and experimental data on the role of air pollution in patients with AD. Recent evidence suggests that a variety of air pollutants, such as environmental tobacco smoke, volatile organic compounds, formaldehyde, toluene, nitrogen dioxide, and particulate matter, act as risk factors for the development or aggravation of AD. These air pollutants probably induce oxidative stress in the skin, leading to skin barrier dysfunction or immune dysregulation. However, these results are still controversial because of the low number of studies, limitations in study design, inaccurate assessment of exposure and absorption, and many other issues. Further research about the adverse effects of air pollution on AD will help to expand our understanding and to establish a better strategy for the prevention and management of AD.

Melatonin attenuates intermittent hypoxia-induced lipid peroxidation and local inflammation in rat adrenal medulla

Chronic intermittent hypoxia (CIH) induces lipid peroxidation and leads to cardiovascular dysfunction, in which impaired activities of the adrenal medulla are involved. This may be caused by CIH-induced injury in the adrenal medulla, for which the mechanism is currently undefined. We tested the hypothesis that melatonin ameliorates the CIH-induced lipid peroxidation, local inflammation and cellular injury in rat adrenal medulla. Adult Sprague–Dawley rats were exposed to air (normoxic control) or hypoxia mimicking a severe recurrent sleep apnoeic condition for 14 days. The injection of melatonin (10 mg/kg) or vehicle was given before the daily hypoxic treatment. We found that levels of malondialdehyde and nitrotyrosine were significantly increased in the vehicle-treated hypoxic group, when compared with the normoxic control or hypoxic group treated with melatonin. Also, the protein levels of antioxidant enzymes (superoxide dismutase (SOD)-1 and SOD-2) were significantly lowered in the hypoxic group treated with vehicle but not in the melatonin group. In addition, the level of macrophage infiltration and the expression of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) and mediators (inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2)) were elevated in the vehicle-treated hypoxic group, but were significantly ameliorated by the melatonin treatment. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. In conclusion, CIH-induced lipid peroxidation causes local inflammation and cellular injury in the adrenal medulla. The antioxidant and anti-inflammatory actions of melatonin are indicative of a protective agent against adrenal damage in patients with severe obstructive sleep apnea syndrome.

Naringin inhibits growth and induces apoptosis by a mechanism dependent on reduced activation of NF‑κB/COX‑2‑caspase-1 pathway in HeLa cervical cancer cells

Naringin (NRG), a bioflavonoid found in citrus fruit extracts, has been pharmacologically evaluated as a potential anticancer agent. This study confirmed a novel mechanism of the anticancer effects of NRG in the human cervical cancer HeLa cell line (HeLa cells). Exposure of HeLa cells to NRG resulted in growth inhibition, as evidenced by a decrease in cell viability. In addition, NRG treatment induced apoptosis, as indicated by the increased apoptotic percentage and the cleaved caspase-3 expression. Importantly, exposure of the cells to NRG attenuated the expression levels of phosphorylated (p) nuclear factor κB (NF-κB) p65 subunit, cyclooxygenase-2 (COX-2) and cysteinyl aspartate proteinase-1 (caspase-1). Treatment with PDTC (an inhibitor of NF-κB) or NS-398 (an inhibitor of COX-2) or SC-3069 (an inhibitor of caspase-1) markedly induced growth inhibition and apoptosis. Treatment with PDTC or NS-398 also reduced caspase-1 expression. Interestingly, PDTC treatment blocked the expression of COX-2 and NS-398 reduced the p-NF-κB p65 expression. Taken together, this study provides novel evidence that NRG induces growth inhibition and apoptosis by inhibiting the NF-κB/COX-2-caspase-1 pathway and that a positive interaction between NF-κB and COX-2 pathway contributes to the growth and antiapoptotic effect in HeLa cells.

Suppression of abdominal aortic aneurysm formation by inhibition of prolyl hydroxylase domain protein through attenuation of inflammation and extracellular matrix disruption

In the present study we sought to determine the effect of CoCl2, an inhibitor of PHD (prolyl hydroxylase domain protein), on the development of AAA (abdominal aortic aneurysm). AAA was induced in C57BL/6 mice by periaortic application of CaCl2 (AAA group). NaCl (0.9%)-treated mice were used as a sham control (SHAM group). Mice were treated with 0.05% CoCl2 in the drinking water (AAA/CoCl2 group). At 1 and 6 weeks after the operation, aortic tissue was excised for further examination. After 6 weeks of CaCl2 treatment, aortic diameter and macrophage infiltration into the aortic adventitia were increased in the AAA group compared with the SHAM group. Treatment with CoCl2 reduced the aneurysmal size and macrophage infiltration compared with the AAA group. Aortic expression of inflammatory cytokines and MCP-1 (monocyte chemoattractant protein-1) and the activities of MMP-9 (matrix metalloproteinase-9) and MMP-2 were enhanced in the AAA group and attenuated in the AAA/CoCl2 group. Expression of cytokines and the activities of MMPs were already increased after 1 week of CaCl2 treatment, but were suppressed by CoCl2 treatment in association with reduced NF-κB (nuclear factor κB) phosphorylation. Treatment with CoCl2 in mice prevented the development of CaCl2-induced AAA in association with reduced inflammation and ECM (extracellular matrix) disruption. The results of the present study suggest that PHD plays a critical role in the development of AAA and that there is a therapeutic potential for PHD inhibitors in the prevention of AAA development.

NF-κB enhances hypoxia-driven T-cell immunosuppression via upregulation of adenosine A(2A) receptors

Hypoxia affects inflammation by modulating T-cell activation via the adenosinergic system. We supposed that, in turn, inflammation influences cell hypoxic behavior and that stimulation of T-cells in inflammatory conditions involves the concerted action of the nuclear factor κB (NF-κB) and the related hypoxia-inducible factor 1α (HIF-1α) on the adenosinergic system. We addressed this hypothesis by monitoring both transcription factors and four adenosinergic signaling parameters - namely adenosine, adenosine deaminase (ADA), adenosine A2A receptor (A2AR) and cAMP - in T-cells stimulated using phorbol myristate acetate and phytohemagglutinin and submitted to hypoxic conditions which were mimicked using CoCl2 treatment. We found that cell viability was more altered in stimulated than in resting cells under hypoxia. Detailed analysis showed that: i) NF-κB activation remained at basal level in resting hypoxic cells but greatly increased following stimulation, stimulated hypoxic cells exhibiting the higher level; ii) HIF-1α production induced by hypoxia was boosted via NF-κB activation in stimulated cells whereas hypoxia increased HIF-1α production in resting cells without further activating NF-κB; iii) A2AR expression and cAMP production increased in stimulated hypoxic cells whereas adenosine level remained unchanged due to ADA regulation; and iv) the presence of H2S, an endogenous signaling molecule in inflammation, reversed the effect of stimulation on cell viability by down-regulating the activity of transcription factors and adenosinergic immunosuppression. We also found that: i) the specific A2AR agonist CGS-21680 increased the suppressive effect of hypoxia on stimulated T-cells, the antagonist ZM-241385 exhibiting the opposite effect; and ii) Rolipram, a selective inhibitor of cAMP-specific phosphodiesterase 4, and 8-Br-cAMP, a cAMP analog which preferentially activates cAMP-dependent protein kinase A (PKA), increased T-cell immunosuppression whereas H-89, a potent and selective inhibitor of cAMP-dependent PKA, restored cell viability. Together, these data indicate that inflammation enhances T-cell sensitivity to hypoxia via NF-κB activation. This process upregulates A2AR expression and enhances cAMP production and PKA activation, resulting in adenosinergic T-cell immunosuppression that can be modulated via H2S.

Activation of the p38 MAPK/NF-κB pathway contributes to doxorubicin-induced inflammation and cytotoxicity in H9c2 cardiac cells

A number of studies have demonstrated that inflammation plays a role in doxorubicin (DOX)-induced cardiotoxicity. However, the molecular mechanism by which DOX induces cardiac inflammation has yet to be fully elucidated. The present study aimed to investigate the role of the p38 mitogen-activated protein kinase (MAPK)/nuclear factor-κB (NF-κB) pathway in DOX-induced inflammation and cytotoxicity. The results of our study demonstrated that the exposure of H9c2 cardiac cells to DOX reduced cell viability and stimulated an inflammatory response, as demonstrated by an increase in the levels of interleukin-1β (IL-1β) and IL-6, as well as tumor necrosis factor-α (TNF-α) production. Notably, DOX exposure induced the overexpression of phosphorylated p38 MAPK and phosphorylation of the NF-κB p65 subunit, which was markedly inhibited by SB203580, a specific inhibitor of p38 MAPK. The inhibition of NF-κB by pyrrolidine dithiocarbamate (PDTC), a selective inhibitor of NF-κB, significantly ameliorated DOX-induced inflammation, leading to a decrease in the levels of IL-1β and IL-6, as well as TNF-α production in H9c2 cells. The pretreatment of H9c2 cells with either SB203580 or PDTC before exposure to DOX significantly attenuated DOX-induced cytotoxicity. In conclusion, our study provides novel data demonstrating that the p38 MAPK/NF-κB pathway is important in the induction of DOX-induced inflammation and cytotoxicity in H9c2 cardiac myocytes.

Inhibition of ROS-activated p38MAPK pathway is involved in the protective effect of H2S against chemical hypoxia-induced inflammation in PC12 cells

We have demonstrated the neuroprotection of hydrogen sulfide (H₂S) against chemical hypoxia-induced injury by inhibiting p38MAPK pathway. The present study attempts to evaluate the effect of H₂S on chemical hypoxia-induced inflammation responses and its mechanisms in PC12 cells. We found that treatment of PC12 cells with cobalt chloride (CoCl₂, a hypoxia mimetic agent) enhanced IL-6 secretion, nitric oxide (NO) generation and expression levels of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). L-canavanine, a selective iNOS inhibitor, partly blocked CoCl₂-induced cytotoxicity, apoptosis and mitochondrial insult. In addition, 7-Nitroindazole (7-NI), an inhibitor of nNOS, also partly attenuated the CoCl₂-induced cytotoxicity. The inhibition of p38MAPK by SB203580 (a selective p38MAPK inhibitor) or genetic silencing of p38MAPK by RNAi (Si-p38) depressed not only CoCl₂-induced iNOS expression, NO production, but also IL-6 secretion. In addition, N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, conferred a similar protective effect of SB203580 or Si-p38 against CoCl₂-induced inflammatory responses. Importantly, pretreatment of PC12 cells with exogenous application of sodium hydrosulfide (a H₂S donor, 400 μmol/l) for 30 min before exposure to CoCl₂ markedly attenuated chemical hypoxia-stimulated iNOS and nNOS expression, NO generation and IL-6 secretion as well as p38MAPK phosphorylation in PC12 cells. Taken together, we demonstrated that p38MAPK-iNOS pathway contributes to chemical hypoxia-induced inflammation and that H₂S produces an anti-inflammatory effect in chemical hypoxia-stimulated PC12 cells, which may be partly due to inhibition of ROS-activated p38MAPK-iNOS pathway.

Development, characterisation and biocompatibility testing of a cobalt-containing titanium phosphate-based glass for engineering of vascularized hard tissues

There is a continuing need to develop scaffold materials that can promote vascularisation throughout the tissue engineered construct. This study investigated the effect of cobalt oxide (CoO) doped into titanium phosphate glasses on material properties, biocompatibility and vascular endothelial growth factor (VEGF) secretion by osteoblastic MG63 cells. Glasses composed of (P2O5)45(Na2O)20(TiO2)05(CaO)30-x(CoO)x(x=0, 5, 10, and 15 mol%) were fabricated and the effect of Co on physicochemical properties including density, glass transition temperature (Tg), degradation rate, ion release, and pH changes was assessed. The results showed that incorporation of CoO into the glass system produced an increase in density with little change in Tg. It was then confirmed that the pH did not change significantly when CoO was incorporated in the glass, and stayed constant at around 6.5-7.0 throughout the dissolution study period of 336 h. Ion release results followed a specific pattern with increasing amounts of CoO. In general, although incorporation of CoO into a titanium phosphate glass increased its density, other bulk and surface properties of the glass did not show any significant changes. Cell culture studies performed using MG63 cells over a 7-day period indicated that the glasses provide a stable surface for cell attachment and are biocompatible. Furthermore, VEGF secretion was significantly enhanced on all glasses compared with standard tissue culture plastic and Co doping enhanced this effect further. In conclusion, the developed Co-doped glasses are stable and biocompatible and thus offer enhanced potential for engineering vascularized tissue.

Transcriptional and translational regulation of COX-2 expression by cadmium in C6 glioma cells

High exposure to cadmium is a risk factor for many neuronal diseases. Overexpression of cyclooxygenase (COX)-2 is linked to many neuroinflammatory and neoplastic diseases. We, herein, investigated the effect of cadmium on the expression of COX-2 in C6 rat glioma cells. Treatment with cadmium sulfate (cadmium) increased the expression of COX-2 mRNA. Remarkably, cadmium treatment further increased expression of not only the N-glycosylated COX-2 protein of 72 kDa but also the unglycosylated COX-2 of 66 kDa, as assessed by the unglycosylated COX-2 induced by tunicamycin or glucosamine, known inhibitors of COX-2 N-glycosylation. Of note, when translation was blocked in the presence of cycloheximide (CHX), levels of both N-glycosylated and unglycosylated COX-2 proteins induced by cadmium rapidly declined but the decline was prevented by MG132, a 26S proteasomal inhibitor. However, in the absence of CHX, cadmium induced and maintained expression of the unglycosylated COX-2 proteins. Pharmacological inhibition studies importantly demonstrated that the cadmium-mediated COX-2 transcriptional upregulation in C6 cells was not shown by exogenous glutathione (GSH) supplementation or treatment with inhibitors of extracellular signal-regulated protein kinase-1/2 (ERK-1/2), p38 MAPK and c-Jun N-terminal protein kinase-1/2 (JNK-1/2), respectively. Expression of COX-2 was not noted in C6 cells exposed to other heavy metals (cobalt or manganese). These results demonstrate that cadmium specifically induces expression of COX-2 through both transcriptional and co-translational (N-glycosylation) regulation in C6 cells in which the cadmium-induced COX-2 transcriptional upregulation is closely related to oxidative stress-dependent activation of the family of MAPKs and the cadmium-induced expression of both N-glycosylated and unglycosylated COX-2 proteins is proteasome- and translation-dependent.

Molecular mechanisms linking endometriosis under oxidative stress with ovarian tumorigenesis and therapeutic modalities

Inflammation plays a role in the pathogenesis of endometriosis. Endometriosis-associated ovarian carcinogenesis might be promoted through oxidative stress-induced increased genomic instability, aberrant methylation, and aberrant chromatin remodeling, as well as mutations of tumor suppressor genes. Aberrant expression of ARID1A, PIK3CA, and NF-kB genes has been recognized as the major target genes involved in oxidative stress-induced carcinogenesis. HNF-1beta appears to play a key role in anti-oxidative defense mechanisms. We discuss the pathophysiologic roles of oxidative stress as somatic mutations as well as highly specific agents that effectively modulate these targets.

Genome integrity, stem cells and hyaluronan

Faithful preservation of genome integrity is the critical mission of stem cells as well as of germ cells. Reviewed are the following mechanisms involved in protecting DNA in these cells: (a) The efflux machinery that can pump out variety of genotoxins in ATP-dependent manner; (b) the mechanisms maintaining minimal metabolic activity which reduces generation of reactive oxidants, by-products of aerobic respiration; (c) the role of hypoxic niche of stem cells providing a gradient of variable oxygen tension; (d)(e) the presence of hyaluronan (HA) and HA receptors on stem cells and in the niche; (f) the role of role of HA in protecting DNA from oxidative damage; (g) the specific role of HA that may play a role protecting DNA in stem cells; (h) the interactions of HA with sperm cells and oocytes that also may shield their DNA from oxidative damage, and (e) mechanisms by which HA exerts the anti-oxidant activity. While HA has multitude of functions its anti-oxidant capabilities are often overlooked but may be of significance in preservation of integrity of stem and germ cells genome.

Gastric diseases in Mongolian gerbils infected with different strains of Helicobacter pylori

Helicobacter pylori (H.pylori) is a bacterium responsible for one of the most widespread infections found in humans. It colonizes the gastric mucosa and can result in chronic gastritis and gastric cancer. The incidence of spontaneous gastric gastritis is low in Mongolian gerbils, and spontaneous H.pylori infection can not be detected in this animal. Since H.pylori-related gastric diseases in Mongolian gerbils are very similar to those in humans, they have been considered as ideal animals to establish H.pylori infection models. However, different strains of H.pylori may induce different types of pathologic changes in Mongolian gerbils. Clarification of the pathogenic mechanisms of different strains of H.pylori may provide a theoretical basis for screening appropriate H.pylori strains and directing individualized treatment in patients with H.pylori-related gastric diseases. In this paper, we review the recent progress in research of gastric diseases in Mongolian gerbils infected with different strains of H.pylori.