p38 MAPK: a dual role in hepatocyte proliferation through reactive oxygen species

The interplay of p38 MAPK signaling and mitochondrial metabolism, a dynamic target in cancer and pathological contexts

Mitochondria play a crucial role in cellular metabolism and bioenergetics, orchestrating various cellular processes, including energy production, metabolism, adaptation to stress, and redox balance. Besides, mitochondria regulate cellular metabolic homeostasis through coordination with multiple signaling pathways. Importantly, the p38 mitogen-activated protein kinase (MAPK) signaling pathway is a key player in the intricate communication with mitochondria, influencing various functions. This review explores the multifaced interaction between the mitochondria and p38 MAPK signaling and the consequent impact on metabolic alterations. Overall, the p38 MAPK pathway governs the activities of key mitochondrial proteins, which are involved in mitochondrial biogenesis, oxidative phosphorylation, thermogenesis, and iron homeostasis. Additionally, p38 MAPK contributes to the regulation of mitochondrial responses to oxidative stress and apoptosis induced by cancer therapies or natural substances by coordinating with other pathways responsible for energy homeostasis. Therefore, dysregulation of these interconnected pathways can lead to various pathologies characterized by aberrant metabolism. Consequently, gaining a deeper understanding of the interaction between mitochondria and the p38 MAPK pathway and their implications presents exciting forecasts for novel therapeutic interventions in cancer and other disorders characterized by metabolic dysregulation.

Dissection of MKK6 and p38 Signaling Using Light-Activated Protein Kinases

Stress-activated signaling pathways orchestrate cellular behaviors and fates. Studying the precise role(s) of stress-activated protein kinases is challenging, because stress conditions induce adaptation and impose selection pressure. To meet this challenge, we have applied an optogenetic system with a single plasmid to express light-activated p38α or its upstream activator, MKK6, in conjunction with live-cell fluorescence microscopy. In starved cells, decaging of constitutively active p38α or MKK6 by brief exposure to UV light elicits rapid p38-mediated signaling, release of cytochrome c from mitochondria, and apoptosis with different kinetics. In parallel, light activation of p38α also suppresses autophagosome formation, similarly to stimulation with growth factors that activate PI3K/Akt/mTORC1 signaling. Active MKK6 negatively regulates serum-induced ERK activity, which is p38-independent as previously reported. Here, we reproduce that result with the one plasmid system and show that although decaging active p38α does not reduce basal ERK activity in our cells, it can block growth factor-stimulated ERK signaling in serum-starved cells. These results clarify the roles of MKK6 and p38α in dynamic signaling programs, which act in concert to actuate apoptotic death while suppressing cell survival mechanisms.

Nanotechnology-mediated photodynamic therapy: Focus on overcoming tumor hypoxia

The oxygen level in the tumor is a critical marker that determines response to different treatments. Cancerous cells can adapt to hypoxia and low pH conditions within the tumor microenvironment (TME) to regulate tumor metabolism, proliferation, and promote tumor metastasis as well as angiogenesis, consequently leading to treatment failure and recurrence. In recent years, widespread attempts have been made to overcome tumor hypoxia through different methods, such as hyperbaric oxygen therapy (HBOT), hyperthermia, O2 carriers, artificial hemoglobin, oxygen generator hydrogels, and peroxide materials. While oxygen is found to be an essential agent to improve the treatment response of photodynamic therapy (PDT) and other cancer treatment modalities, the development of hypoxia within the tumor is highly associated with PDT failure. Recently, the use of nanoparticles has been a hot topic for researchers and exploited to overcome hypoxia through Oxygen-generating hydrogels, O2 nanocarriers, and O2 -generating nanoparticles. This review aimed to discuss the role of nanotechnology in tumor oxygenation and highlight the challenges, prospective, and recent advances in this area to improve PDT outcomes. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Sericin enhances ammonia detoxification by promotes urea cycle enzyme genes and activates hepatic autophagy in relation to CARD-9/MAPK pathway

Urea cycle is an important metabolic process that initiates in liver mitochondria and converts ammonia to urea. The impairment of ammonia detoxification, both primary and secondary causes, lead to hyperammonemia, a life-threatening condition affecting to the brain. Current treatments are not enough effective. In addition, our recent proteomics study in hypercholesterolemic rat model demonstrated that sericin enhances hepatic nitrogenous waste removal through carbamoyl-phosphate synthase 1 (CPS-1), aldehyde dehydrogenase-2 (ALDH-2), and uricase proteins. However, the underlining mechanisms regard to this property is not clarified yet. Therefore, the present study aims to examine the effect of sericin on urea cycle enzyme genes (CPS-1 and ornithine transcarbamylase; OTC) and proteins (mitogen-activated protein kinase; MAPK, caspase recruitment domain-containing protein 9; CARD-9, Microtubule-associated protein light chain 3; LC-3), which relate to urea production and liver homeostasis in hepatic cell line (HepG2) and hypercholesterolemic rat treated with or without sericin. qRT-PCR, immunohistochemistry, and electron microscopy techniques were performed. In vitro study determined that high dose of sericin at 1 mg/ml increased liver detoxification enzyme (Cytochrome P450 1A2; CYP1A2 and ALDH-2) and urea cycle enzyme (CPS-1 and OTC) genes. Both in HepG2 cell and rat liver mitochondria, sericin significantly downregulated CARD-9 (apoptotic protein) expression while upregulated MAPK (hepatic homeostasis protein) and LC-3 (autophagic protein) expressions. Hence, it might be concluded that sericin promotes ammonia detoxification by both increases urea cycle enzyme genes and enhances hepatic autophagy in associated with CARD-9/MAPK pathway (as shown by their own negative relationship). This study presents another beneficial property of sericin to develop an upcoming candidate for ammonia toxicity alleviation and liver function improvement.

Shikimic Acid Regulates the NF-κB/MAPK Signaling Pathway and Gut Microbiota to Ameliorate DSS-Induced Ulcerative Colitis

Shikimic acid (SA) is a compound extracted from the plant anise and has anti-inflammatory effects. However, any impact on intestinal inflammation or mechanisms involved has not been investigated. The present study used a dextran sulfate sodium (DSS)-induced mouse colitis model to investigate the effects of SA on intestinal inflammation. Intragastric administration of SA slowed DSS-induced weight loss, reduced disease activity index (DAI) score, enhanced the intestinal barrier, reduced the destruction of the colonic structure, inhibited the phosphorylation of key proteins in MAPK and NF-κB signaling pathways, inhibited the expression of inflammatory factors TNF-α, IL-1β, and MPO (P < 0.05), decreased IFN-γ expression (P < 0.05), and increased immunoglobulin IgG content (P < 0.05). After 50 mg/kg SA treatment, the content of Bacteroidetes increased and Proteobacteria decreased in the cecal feces of mice with colitis (P < 0.05) and the richness of gut species increased. In conclusion, SA could improve intestinal inflammation and enhance intestinal immunity, indicating its suitability as a therapeutic candidate.

Arabinogalactan ameliorates benzo[a]pyrene-induced intestinal epithelial barrier dysfunction via AhR/MAPK signaling pathway

Benzo[a]pyrene (B[a]P), a kind of pollutant, can disrupt the gut microbiota, but its effects on the function of intestinal epithelial barrier (IEB) is still unclear. Arabinogalactan (AG), a natural polysaccharide, can protect intestinal tract. Thus, the purpose of this study was to evaluate the effect of B[a]P on IEB function and the mitigation effect of AG on the IEB dysfunction induced by B[a]P using a Caco-2 cell monolayer model. We found B[a]P could damage the IEB integrity by inducing cell cytotoxicity, increasing lactate dehydrogenase leakage, decreasing the transepithelial electrical resistance, and increasing fluorescein isothiocyanate-dextran flux. The mechanism of B[a]P-induced IEB damage may through induction of oxidative stress, including increasing reactive oxygen species levels, decreasing glutathione levels, reducing the activity of superoxide dismutase, and increasing malonaldehyde levels. Moreover, it can be due to increasing secretion of pro-inflammatory cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor [TNF]-α), down-regulated expression of tight junction (TJ) proteins (claudin-1, zonula occludens [ZO]-1, and occludin), and induced activation of aryl hydrocarbon receptor (AhR)/mitogen activated protein kinase (MAPK) signaling pathway. Remarkably, AG ameliorated B[a]P-induced IEB dysfunction through inhibited oxidative stress and pro-inflammatory factor secretion. Our study demonstrated B[a]P could damage the IEB and AG could alleviate this damage.

Attenuation of cancer proliferation by suppression of glypican-1 and its pleiotropic effects in neoplastic behavior

Glypicans (GPC1-6) are associated with tumorigenic processes and their involvement in neoplastic behavior has been discussed in different cancer types. Here, a cancer-wide GPC expression study, using clinical cancer patient data in The Cancer Genome Atlas, reveals net upregulation of GPC1 and GPC2 in primary solid tumors, whereas GPC3, GPC5 and GPC6 display lowered expression pattern compared to normal tissues. Focusing on GPC1, survival analyses of the clinical cancer patient data reveal statistically significant correlation between high expression of GPC1 and poor prognosis in 10 particular cancer types i.e., bladder urothelial carcinoma, brain lower grade glioma, liver hepatocellular carcinoma, colon adenocarcinoma, kidney renal clear cell carcinoma, lung adenocarcinoma, mesothelioma, ovarian serous cystadenocarcinoma, uterine corpus endometrial carcinoma and uveal melanoma. In vitro studies targeting GPC1 expression by CRISPR/Cas9 or siRNA or treatment with an anti-GPC1 antibody resulted in attenuation of proliferation of cancer cells from bladder carcinoma, glioma and hepatocellular carcinoma patients (T24, U87 and HepG2 cells). Further, overexpression of GPC1 exhibited a significant and negative correlation between GPC1 expression and proliferation of T24 cells. Attempt to reveal the mechanism through which downregulation of GPC1 leads to attenuation of tumor growth using systematic Ingenuity Pathway Analysis indicate that suppression of GPC1 results in ECM-mediated inhibition of specific pro-cancer signaling pathways involving TGF-β and p38 MAPK. Identified differential expression and pleiotropic effects of GPCs in specific cancer types emphasize their potential of as novel diagnostic tools and prognostic factors and open doors for future GPC targeted therapy.

TIGAR Protects Cochlear Hair Cells against Teicoplanin-Induced Damage

Teicoplanin is a glycopeptide antibiotic used to treat severe staphylococcal infections. It has been claimed that teicoplanin possesses ototoxic potential, although its toxic effects on cochlear hair cells (HCs) remain unknown. The TP53-induced glycolysis and apoptosis regulator (TIGAR) plays a crucial role in promoting cell survival. Prior research has demonstrated that TIGAR protects spiral ganglion neurons against cisplatin damage. However, the significance of TIGAR in damage to mammalian HCs has not yet been investigated. In this study, firstly, we discovered that teicoplanin caused dose-dependent cell death in vitro in both HEI-OC1 cells and cochlear HCs. Next, we discovered that HCs and HEI-OC1 cells treated with teicoplanin exhibited a dramatically decrease in TIGAR expression. To investigate the involvement of TIGAR in inner ear injury caused by teicoplanin, the expression of TIGAR was either upregulated via recombinant adenovirus or downregulated by shRNA in HEI-OC1 cells. Overexpression of TIGAR increased cell viability, decreased apoptosis, and decreased intracellular reactive oxygen species (ROS) level, whereas downregulation of TIGAR decreased cell viability, exacerbated apoptosis, and elevated ROS level following teicoplanin injury. Finally, antioxidant therapy with N-acetyl-L-cysteine decreased ROS level, prevented cell death, and restored p38/phosphorylation-p38 expression levels in HEI-OC1 cells injured by teicoplanin. This study demonstrates that TIGAR may be a promising novel target for the prevention of teicoplanin-induced ototoxicity.

P38 MAPK and Radiotherapy: Foes or Friends?

Over the last 30 years, the study of the cellular response to ionizing radiation (IR) has increased exponentially. Among the various signaling pathways affected by IR, p38 MAPK has been shown to be activated both in vitro and in vivo, with involvement in key processes triggered by IR-mediated genotoxic insult, such as the cell cycle, apoptosis or senescence. However, we do not yet have a definitive clue about the role of p38 MAPK in terms of radioresistance/sensitivity and its potential use to improve current radiotherapy. In this review, we summarize the current knowledge on this family of MAPKs in response to IR as well as in different aspects related to radiotherapy, such as their role in the control of REDOX, fibrosis, and in the radiosensitizing effect of several compounds.

Protective effects of lycopene on TiO2 nanoparticle-induced damage in the liver of mice

Titanium dioxide nanoparticles (nano-TiO₂ ) is one of the most widely used and produced nanomaterials. Studies have demonstrated that nano-TiO₂ could induce hepatotoxicity through oxidative stress, and lycopene has strong antioxidant capacity. The present study aimed to explore if lycopene protects the liver of mice from nano-TiO₂ damage. Ninety-six ICR mice were randomly divided into eight groups. They were control group, nano-TiO₂ -treated group (50 mg/kg BW), lycopene-treated groups (5, 20, and 40 mg/kg BW), and 50 mg/kg BW nano-TiO₂ - and lycopene-co-treated groups (nano-TiO₂  + 5 mg/kg BW of lycopene, nano-TiO₂  + 20 mg/kg BW of lycopene, nano-TiO₂  + 40 mg/kg BW of lycopene). After treated by gavage for 30 days, the histopathology of the liver was observed. Liver function was evaluated using changes in serum biochemical indicators of the liver (AST, ALT, ALP); and the level of ROS was indirectly reflected by the level of SOD, GSH-Px, MDA, GSH, and T-AOC. TUNEL assay was performed to examine the apoptosis of hepatocytes. Proteins of p53, cleaved-caspase 9, cleaved-caspase 3, Bcl-2, and Bax as well as p38 were detected. Results showed that lycopene alleviated the liver pathological damage and reduced the injury to liver function induced by nano-TiO₂ , as well as decreased nano-TiO₂ -induced ROS. Meanwhile, lycopene mitigated apoptosis resulting from nano-TiO₂ , accompanied by the reversed expression of apoptosis-related proteins. Furthermore, lycopene significantly reversed the upregulation of p-p38 induced by nano-TiO₂ . In conclusion, this study demonstrated that nano-TiO₂ resulted in hepatocyte apoptosis through ROS/ROS-p38 MAPK pathway and led to liver function injury. Lycopene protected mice liver against the hepatotoxicity of nano-TiO₂ through antioxidant property.

2, 2', 4, 4'-tetrabromodiphenyl ether induces placental toxicity via activation of p38 MAPK signaling pathway in vivo and in vitro

2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) is one of the most important polybrominated diphenyl ethers (PBDEs) congeners, and epidemiological studies have shown that it can cause adverse pregnancy outcomes. The aim of our study was to investigate the role of placental injury in BDE-47-induced adverse pregnancy outcomes through in vivo and in vitro models. From day 0.5 to day 16.5 of pregnancy of ICR mice, BDE-47 oral doses of 0, 25, 50 and 100 mg/kg/day were administered. Immunohistochemical staining found that BDE-47 inhibited the expression of CD34 in mouse placenta, and ELISA results showed that BDE-47 reduced the levels of VEGF and PlGF in the serum of pregnant mice. Western blot assays found that the expression levels of VEGF-A and invasion-related factors were decreased in the placentas of BDE-47-treated group, which indicated that BDE-47 could impair placental angiogenesis. Furthermore, BDE-47 inhibited proliferation, increased apoptosis and autophagy, and activated p38 MAPK signaling pathway in mouse placental tissue. In vitro, HTR-8/SVneo cells were treated with 0, 5, 10, 20 μM BDE-47 for 24 h. Wound healing assays and Transwell assays showed that BDE-47 inhibited the migration and invasion ability of HTR-8/SVneo cells. We also found that BDE-47 inhibited the proliferation of HTR-8/SVneo cells and increased apoptosis and autophagy. BDE-47 activated p38 MAPK signaling pathway in HTR-8/SVneo cells, and inhibition of p38 MAPK signaling pathway in HTR-8/SVneo cells restored the effects caused by BDE-47. In conclusion, BDE-47 impairs placental angiogenesis by inhibiting cell migration and invasion, and induces placental toxicity by inhibiting proliferation, increasing apoptosis and autophagy. In vitro, activation of p38 MAPK signaling pathway is involved in the processes of placental injury by BDE-47.

p38 MAPK Is a Major Regulator of Amyloid Beta-Induced IL-6 Expression in Human Microglia

The accumulation of amyloid beta (Aβ) plaques in the brain is a hallmark of Alzheimer's disease (AD) pathology. Microglial activation-mediated neuroinflammation has been implicated in the pathogenesis of AD and the expression levels of interleukin-6 (IL-6) were increased in the brains of AD patients. However, the mechanisms by which IL-6 expression is regulated in human microglia are incompletely understood. Here, we show that Aβ1-40 oligomers (Aβ40) dose-dependently stimulate IL-6 expression in HMC3 human microglial cells. Treatment with Aβ40 promotes the transcription of IL-6 and tumor necrosis factor α (TNFα) mRNAs in both HMC3 and THP-1 cells. Mechanistic studies reveal that Aβ40-induced increase of IL-6 secretion is associated with the activation of p38 mitogen-activated protein kinase (p38 MAPK). Inhibition of p38 MAPK by BIRB 796 or SB202190 abrogates Aβ40-induced increase of IL-6 production. Through analyzing brain specimens, we found that the immunoreactivity for IL-6 and phosphorylated (the activated form) p38 MAPK was markedly higher in microglia of AD patients than in age-matched control subjects. Moreover, our studies identified the co-localization of IL-6 with phosphorylated p38 MAPK in microglia in the cortices of AD patients. Taken together, these results indicate that p38 MAPK is a major regulator of Aβ-induced IL-6 production in human microglia, which suggests that targeting p38 MAPK may represent a new approach to ameliorate Aβ accumulation-induced neuroinflammation in AD.

The role of protein kinases as key drivers of metabolic dysfunction-associated fatty liver disease progression: New insights and future directions

Metabolic dysfunction-associated fatty liver disease (MAFLD), proposed in 2020 is a novel term for non-alcoholic fatty liver disease (NAFLD) which was coined for the first time in 1980. It is a leading cause of the most chronic liver disease and hepatic failure all over the world, and unfortunately, with no licensed drugs for treatment yet. The progress of the disease is driven by the triggered inflammatory process, oxidative stress, and insulin resistance in many pathways, starting with simple hepatic steatosis to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and liver cancer. Protein kinases (PKs), such as MAPK, ErbB, PKC, PI3K/Akt, and mTOR, govern most of the pathological pathways by acting on various downstream key points in MAFLD and regulating both hepatic gluco- lipo-neogenesis and inflammation. Therefore, modulating the function of those potential protein kinases that are effectively involved in MAFLD might be a promising therapeutic approach for tackling this disease. In the current review, we have discussed the key role of protein kinases in the pathogenesis of MAFLD and performed a protein-protein interaction (PPI) network among the main proteins of each kinase pathway with MAFLD-related proteins to predict the most likely targets of the PKs in MAFLD. Moreover, we have reported the experimental, pre-clinical, and clinical data for the most recent investigated molecules that are activating p38-MAPK and AMPK proteins and inhibiting the other PKs to improve MAFLD condition by regulating oxidation and inflammation signalling.

Effect of a Plateau Environment on the Oxidation State of the Heart and Liver through AMPK/p38 MAPK/Nrf2-ARE Signaling Pathways in Tibetan and DLY Pigs

This study evaluated the effect of a plateau environment on the heart and liver oxidation state of Tibetan pigs (TPs) and DLY pigs through analyzing AMPK, p38 MAPK, and Nrf2 signaling pathways. Twelve 120-day-old TPs and twelve 120-day-old DLY pigs were randomly divided into two groups in a plateau environment for three weeks. Exposed to a plateau environment, TPs exhibited a lower (p < 0.05) malondialdehyde level but higher (p < 0.05) glutathione, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) activities in the liver and heart than those observed in DLY pigs. TPs also showed higher (p < 0.05) mRNA levels of SOD and GSH-Px in the liver and heart compared with those of DLY pigs. The TPs showed higher (p < 0.05) mRNA and protein levels of AMPK and Nrf2 in the liver and heart compared with those of DLY pigs. Furthermore, TPs showed higher (p < 0.05) mRNA and protein levels of p38 MAPK in the heart and higher mRNA levels of p38 MAPK in the liver compared with those of DLY pigs under a plateau environment. In summary, TPs possess a stronger antioxidant capacity in the heart and liver than that of DLY pigs in a plateau environment through AMPK/p38 MAPK/Nrf2-ARE signaling pathways.

Actein contributes to black cohosh extract-induced genotoxicity in human TK6 cells

Black cohosh extract (BCE) is one of the most popular botanical products for relieving menopausal symptoms. However, recent studies indicate that BCE is not only ineffective for menopausal therapy, but also induces genotoxicity through an aneugenic mode of action (MoA). In this study, the cytotoxicity of five constituents of BCE was evaluated in human lymphoblastoid TK6 cells. Among the five constituents, actein (up to 50 μM) showed the highest cytotoxicity and was thus selected for further genotoxicity evaluations. Actein caused DNA damage proportionally to concentration as evidenced by the phosphorylation of the histone protein H2A.X (γH2A.X) and resulted in chromosomal damage as measured by the increased percentage of micronuclei (MN) in cells. In addition, actein activated DNA damage response (DDR) pathway through induction of p-ATM, p-Chk1, and p-Chk2, which subsequently induced cell cycle changes and apoptosis. Moreover, both BCE and actein increased intracellular reactive oxygen species (ROS) production, decreased glutathione levels, and activated the mitogen-activated protein kinases (MAPK) signaling pathway. N-acetylcysteine, a ROS scavenger, attenuated BCE- and actein-induced ROS production, apoptosis, and DNA damage. These findings indicate that BCE- and actein-induced genotoxicity is mediated through oxidative stress. Taken together, our data show that actein is likely one of the major contributors to BCE-induced genotoxicity.

The Contribution of the Interleukin-4-Induced Epithelial Cell Senescence to Glandular Fibrosis in IgG4-Related Sialadenitis

OBJECTIVE

Immunoglobulin G4-related sialadenitis (IgG4-RS) is a chronic fibro-inflammatory disease characterized by glandular fibrosis and hyposalivation. Here we aimed to explore the role of cellular senescence in the pathogenesis of IgG4-RS-related fibrosis.

METHODS

The expression of senescence markers and proinflammatory cytokines in the submandibular glands (SMGs) of IgG4-RS patients (n = 18) and controls (n = 14) was determined by proteomics, real-time polymerase chain reaction (PCR), western blot, and immunohistochemistry. After interleukin-4 (IL-4) treatment, high-throughput RNA-sequencing was performed to identify the differentially expressed genes in SMG-C6 cells. A glandular fibrosis model was established by the intraglandular injection of IL-4 into mouse SMGs (n = 8 per group).

RESULTS

Salivary acinar and ductal epithelial cells underwent senescence in IgG4-RS patients, as indicated by the elevated activity of senescence-associated β-galactosidase, lipofuscin accumulation, enhanced expression of senescence markers (p53 and p16^INK4A ), and upregulation of senescence-associated secretory phenotype factors. Moreover, there was a significant increase in IL-4 levels in SMGs of IgG4-RS patients, which positively correlated with p16^INK4A expression and the fibrosis score. Incubation with IL-4 exacerbated salivary epithelial cell senescence by increasing the expression of p16^INK4A through ROS-p38 mitogen-activated protein kinase (MAPK) pathway. The supernatant collected from IL-4-induced senescent SMG-C6 cells enhanced fibroblast activation and matrix protein production. Furthermore, injecting IL-4 promoted fibrosis and senescence phenotypes in the SMGs in vivo.

CONCLUSION

The cellular senescence induced by IL-4 through the ROS-p38 MAPK-p16^INK4A pathway promoted fibrogenesis during IgG4-RS. Our data suggest that cellular senescence could serve as a novel therapeutic target for treating IgG4-RS.

The promising therapeutic potentials of ginsenosides mediated through p38 MAPK signaling inhibition

The p38 mitogen-activated protein kinases (p38 MAPK) is a 38kD polypeptide recognized as the target for many potential anti-inflammatory agents. Accumulating evidence indicates that p38 MAPK could perform many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors. Ginseng is an exceptionally valued medicinal plant of the family Araliaceae (Panax genus). Recently, several studies targeted the therapeutic effects of purified individual ginsenoside, the most significant active ingredient of ginseng, and studied its particular molecular mechanism(s) of action rather than whole-plant extracts. Interestingly, several ginsenosides: ginsenosides compound K, F1, Rb1, Rb3, Rc, Rd, Re, Rf, Rg1, Rg2, Rg3, Rg5, Rh1, Rh2, Ro, notoginsenoside R1, and protopanaxadiol have shown to possess great therapeutic potentials mediated by their ability to downregulate p38 MAPK signaling in different cell lines and experimental animal models. Our review compiles the research findings of various ginsenosides as potent anti-inflammatory agents, highlighting the crucial role of p38 MAPK suppression in their pharmacological actions. In addition, in silico studies were conducted to explore the probable binding of these ginsenosides to p38 MAPK. The results obtained proposed p38 MAPK involvement in the beneficial pharmacological activities of ginsenosides in different ailments.

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p38 MAPK plays many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors.

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Several ginsenosides showed to possess great therapeutic potentials mediated by its ability to downregulate p38 MAPK signaling.

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in silico ​studies were conducted to explore the binding of these ginsenosides to p38 MAPK and evidenced the promising their inhibitory effect.

ROS-Nrf2 pathway mediates the development of TGF-β1-induced epithelial-mesenchymal transition through the activation of Notch signaling

Epithelial-mesenchymal transition (EMT) is a cellular process by which epithelial cells transform to acquire mesenchymal phenotypes. Accumulating evidence indicate the involvement of EMT in the progression of malignant diseases. Notch signaling mediates TGF-β1-induced EMT through direct transcriptional activation of Snai1. The molecular mechanism how TGF-β1 activates Notch signaling, however, remains unknown. In this study, we show a pivotal role for reactive oxygen species (ROS)-Nrf2 pathway in TGF-β1-induced Notch signaling activation and EMT development. TGF-β1 induces Nrf2 activation through ROS production. Inhibiting Nrf2 activation either by reducing ROS levels by N-acetylcysteine or by knocking down of Nrf2 by small interfering RNA attenuated both Notch signaling activation and EMT development. TGF-β1 induced the transcription of Notch4 via Nrf2-dependent promoter activation. In conclusion, our study indicates the ROS-Nrf2 pathway mediates the development of TGF-β1-induced EMT through the activation of Notch signaling.

In search of elixir: Pharmacological agents against stem cell senescence

Stem cell senescence causes different complications. In addition to the aging phenomenon, stem cell senescence has been investigated in various concepts such as cancer, adverse drug effects, and as a limiting factor in cell therapy. This manuscript examines protective medicines and supplements which are capable of hindering stem cell senescence. We searched the databases such as EMBASE, PubMed, and Web of Science with the keywords “stem cell,” “progenitor cell,” “satellite,” “senescence” and excluded the keywords “cancer,” “tumor,” “malignancy” and “carcinoma” until June 2020. Among these results, we chose 47 relevant studies. Our investigation indicates that most of these studies examined endothelial progenitor cells, hematopoietic stem cells, mesenchymal stem cells, adipose-derived stem cells, and a few others were about less-discussed types of stem cells such as cardiac stem cells, myeloblasts, and induced pluripotent stem cells. From another aspect, 17β-Estradiol, melatonin, metformin, rapamycin, coenzyme Q10, N-acetyl cysteine, and vitamin C were the most studied agents, while the main protective mechanism was through telomerase activity enhancement or oxidative damage ablation.

Although many of these studies are in vitro, they are still worthwhile. Stem cell senescence in the in vitro expansion stage is an essential concern in clinical procedures of cell therapy. Moreover, in vitro studies are the first step for further in vivo and clinical studies. It is noteworthy to mention the fact that these protective agents have been used in the clinical setting for various purposes for a long time. Given that, we only need to examine their systemic anti-senescence effects and effective dosages.

LR12 Promotes Liver Repair by Improving the Resolution of Inflammation and Liver Regeneration in Mice with Thioacetamide- (TAA-) Induced Acute Liver Failure

Background

Triggering receptor expressed on myeloid cells-1 (TREM-1) controls the mobilization of inflammatory cells in response to injury and consequently enhances liver damage. LR12 is a TREM-1 inhibitory peptide. However, the role of LR12 in acute liver failure (ALF) has remained elusive. This study was aimed at indicating whether LR12 could promote liver repair in mice with thioacetamide- (TAA-) induced ALF.

Methods

BALB/c mice were intraperitoneally injected with TAA, followed by intravenous injection of LR12. Damage and regeneration of the liver were assessed. LO2 cells and macrophages were used to assess the therapeutic effects of LR12.

Results

Mice treated with TAA for 24 h developed ALF, while liver inflammation was alleviated after LR12 treatment. Moreover, LR12 promoted hepatocyte regeneration in mice with TAA-induced ALF. In vitro, the supernatant from TAA+LR12-treated macrophages promoted the proliferation of LO2 cells. Cytokine protein microarray analysis suggested that LR12 promoted the secretion of C-C chemokine ligand 20 (CCL20) from macrophages. Besides, neutralization of CCL20 blocked the effects of LR12, thus inhibited the proliferation of LO2 cells in vitro, aggregated the liver inflammation, and restrained hepatocyte regeneration in ALF mice in vivo. Furthermore, we also found that LR12 activated the p38 mitogen-activated protein kinase (MAPK) pathway in hepatocytes through promoting the secretion of CCL20 from macrophages.

Conclusions

LR12 could improve the resolution of inflammation and liver regeneration in mice with TAA-induced ALF by promoting the secretion of CCL20 from macrophages and activating the p38 MAPK pathway. Therefore, LR12 could be an attractive therapeutic target for the treatment of ALF.

Modulating NF-κB, MAPK, and PI3K/AKT signaling by ergothioneine attenuates iron overload-induced hepatocellular injury in rats

The liver is highly susceptible to iron overload-evoked oxidative injury. Ergothioneine is a thio-histidine amino acid that has exhibited strong antioxidant and metal chelating activities. This study aimed at exploring the potential modulating effects of ergothioneine on iron-triggered liver injury. The results showed that ergothioneine inhibited iron-evoked inflammation and apoptosis as demonstrated by a significant reduction in tumor necrosis factor-α and interleukin-6 levels and in caspase-3 activity. Ergothioneine significantly improved liver cell survival as indicated by modulating phosphatidylinositol 3-kinase/protein kinase B signaling. Consistent with reduced necrotic cell death, ergothioneine diminished the iron-evoked histopathological changes and decreased serum activity of the liver enzymes. Mechanistically, ergothioneine reduced nuclear translocation of nuclear factor kappa B p65 and modulated p38 mitogen-activated protein kinase/c-Fos signaling. In addition, it enhanced the liver tissue antioxidant potential and curbed hepatic iron load. Together, these results point out the modulatory effects of ergothioneine on iron-evoked liver cell injury that are possibly mediated via anti-inflammatory, antioxidant, and possible iron chelation capabilities.

Role of NADPH oxidase in MAPK signaling activation by a 50 Hz magnetic field in human neuroblastoma cells

Our previous studies have shown that intermittent exposure to a 50-Hz, 100-µT sine wave magnetic field (MF) promotes human NB69 cell proliferation, mediated by activation of the epidermal growth factor receptor (EGFR) and pathways MAPK-ERK1/2 and p38; being the effects on proliferation and p38 activation blocked by the chelator N-acetylcysteine. The present work investigates the MF effects on free radical (FR) production, and the potential involvement of NADPH oxidase, the main source of reactive oxygen species (ROS), in the MF-induced activation of MAPK pathways. To this end, the field effects on MAPK-ERK1/2, -p38 and -JNK activation in the presence or absence of the NADPH oxidase inhibitor, diphenyleneiodonium chloride (DPI), as well as the expression of the p67phox subunit, were analyzed. The results revealed that field exposure increases FR production and induces early, transient expression of the cytosolic component of the NADPH oxidase, p67phox. Also, the MF-induced activation of the MAPK-JNK pathway, but not that of -ERK1/2 or -p38 pathways, was prevented in the presence of the DPI, which has been shown to significantly reduce p67phox expression. These data, together with those from previous studies, identify various, FR-dependent or -independent mechanisms, involved in the MF-induced proliferative response mediated by MAPK signaling activation.

Targeting Mitogen-Activated Protein Kinases by Natural Products: A Novel Therapeutic Approach for Inflammatory Bowel Diseases

An increase in the prevalence of Inflammatory Bowel Diseases (IBD) as a multifactorial intestinal chronic inflammation as well as the absence of a certain cure, has created an innovative era in the management of IBD by molecule/pathway-based anti-inflammatory approaches. There are credible documentations that demonstrate Mitogen-Activated Protein Kinases (MAPK) acts as IBD regulator. Upon the activation of MAPK signalling pathway, the transcription and expression of various encoding inflammatory molecules implicated in IBD are altered, thereby exacerbating the inflammation development. The current pharmacological management of IBD, including drug and biological therapies are expensive, possess temporary relief and some adverse effects. In this context, a variety of dietary fruits or medicinal herbs have received worldwide attention versus the development of IBD. Infact, natural ingredients, such as Flavaglines, Fisetin, Myricitrin, Cardamonin, Curcumin, Octacosanol and Mangiferin possess protective and therapeutic effects against IBD via modulation of different segments of MAPK signaling pathway. This review paper calls attention to the role of MAPK signaling triggered by natural products in the prevention and treatment of IBD.

The combined treatment of NAD+ and atorvastatin ameliorates the development of experimental autoimmune encephalomyelitis in C57BL/6 mice

Multiple sclerosis (MS) is a demyelinating and degenerating disorder of the central nervous system impacting many patients worldwide. Due to the complex pathogenesis of MS, drugs to treat MS often show partial effectiveness. Earlier experiments have demonstrated that both atorvastatin and nicotinamide adenine dinucleotide (NAD+) may ameliorate experimental autoimmune encephalomyelitis (EAE), which is known as a classical model of MS, via different protective mechanisms. Since combination therapy can exhibit more beneficial effects than monotherapy, we observed the protective effects of combined treatment of atorvastatin and NAD+ in EAE mice. Our results showed that the combined treatment of these two drugs at half of their optimal dosages had synergistic effect to alleviate the severity of EAE in mice than treatment with each alone. The combined treatment of EAE mice with atorvastatin plus NAD+ relieved the clinical signs and histologic changes, increased the proportion of Treg cells, attenuated IL-17 production, reduced proinflammatory cytokine secretion of Th17 cells, and increased cytokine secretion of Treg cells. In addition, the combined treatment also diminished phosphorylation of both P38 MAPK and ERK, while elevated SIRT1 expression. Taken together, these data suggested that combined treatment with NAD+ and atorvastatin could attenuate the progression of EAE by synergistic immune regulation.

Protective and Detrimental Roles of p38α Mitogen-Activated Protein Kinase in Different Stages of Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

Neutrophil infiltration is a hallmark of nonalcoholic steatohepatitis (NASH), but how this occurs during the progression from steatosis to NASH remains obscure. Human NASH features hepatic neutrophil infiltration and up-regulation of major neutrophil-recruiting chemokines (e.g., chemokine [C-X-C motif] ligand 1 [CXCL1] and interleukin [IL]-8). However, mice fed a high-fat diet (HFD) only develop fatty liver without significant neutrophil infiltration or elevation of chemokines. The aim of this study was to determine why mice are resistant to NASH development and the involvement of p38 mitogen-activated protein kinase (p38) activated by neutrophil-derived oxidative stress in the pathogenesis of NASH.

APPROACH AND RESULTS

Inflamed human hepatocytes attracted neutrophils more effectively than inflamed mouse hepatocytes because of the greater induction of CXCL1 and IL-8 in human hepatocytes. Hepatic overexpression of Cxcl1 and/or IL-8 promoted steatosis-to-NASH progression in HFD-fed mice by inducing liver inflammation, injury, and p38 activation. Pharmacological inhibition of p38α/β or hepatocyte-specific deletion of p38a (a predominant form in the liver) attenuated liver injury and fibrosis in the HFD^+Cxcl1 -induced NASH model that is associated with strong hepatic p38α activation. In contrast, hepatocyte-specific deletion of p38a in HFD-induced fatty liver where p38α activation is relatively weak exacerbated steatosis and liver injury. Mechanistically, weak p38α activation in fatty liver up-regulated the genes involved in fatty acid β-oxidation through peroxisome proliferator-activated receptor alpha phosphorylation, thereby reducing steatosis. Conversely, strong p38α activation in NASH promoted caspase-3 cleavage, CCAAT-enhancer-binding proteins homologous protein expression, and B cell lymphoma 2 phosphorylation, thereby exacerbating hepatocyte death.

CONCLUSIONS

Genetic ablation of hepatic p38a increases simple steatosis but ameliorates oxidative stress-driven NASH, indicating that p38α plays distinct roles depending on the disease stages, which may set the stage for investigating p38α as a therapeutic target for the treatment of NASH.

Intranasal administration of Cytoglobin modifies human umbilical cord‑derived mesenchymal stem cells and improves hypoxic‑ischemia brain damage in neonatal rats by modulating p38 MAPK signaling‑mediated apoptosis

Neonatal hypoxic‑ischemic brain damage (HIBD) is a common clinical syndrome in newborns. Hypothermia is the only approved therapy for the clinical treatment; however, the therapeutic window of hypothermia is confined to 6 h after birth and even then, >40% of the infants either die or survive with various impairments, including cerebral palsy, seizure disorder and intellectual disability following hypothermic treatment. The aim of the present study was to determine whether nasal transplantation of Cytoglobin (CYGB) genetically modified human umbilical cord‑derived mesenchymal stem cells (CYGB‑HuMSCs) exhibited protective effects in neonatal rats with HIBD compared with those treated without genetically modified CYGB. A total of 120 neonatal Sprague‑Dawley rats (postnatal day 7) were assigned to either a Sham, HIBD, HuMSCs or CYGB‑HuMSCs group (n = 30 rats/group). For HIBD modeling, rats underwent left carotid artery ligation and were exposed to 8% oxygen for 2.5 h. A total of 30 min after HI, HuMSCs (or CYGB‑HuMSCs) labeled with enhanced‑green fluorescent protein (eGFP) were intranasally administered. After modeling for 3, 14 and 29 days, five randomly selected rats were sacrificed in each group, and the expression levels of CYGB, ERK, JNK and p38 in brain tissues were determined. Nissl staining of the cortex and hippocampal Cornu Ammonis 1 area of rats in each group were compared after 3 days of modeling. TUNEL assay and immunofluorescence were performed 3 days after modeling. Long term memory in rats was assessed using a Morris‑water maze 29 days after modeling. The HIBD group demonstrated significant deficiencies compared with the Sham group based on Nissl staining, TUNEL assay and the Morris‑water maze test. HuMSC treated rats exhibited improvement on in all the tests, and CYGB‑HuMSCs treatment resulted in further improvements. PCR and western blotting results indicated that the CYGB mRNA and protein levels were increased from day 3 to day 29 after transplantation of CYGB‑HuMSCs. Furthermore, it was identified that CYGB‑HuMSC transplantation suppressed p38 signaling at all experimental time points. Immunofluorescence indicated the scattered presence of HuMSCs or CYGB‑HuMSCs in damaged brain tissue. No eGFP and glial fibrillary acidic protein or eGFP and neuron‑specific enolase double‑stained positive cells were found in the brain tissues. Therefore, CYGB‑HuMSCs may serve as a gene transporter, as well as exert a neuroprotective and antiapoptotic effect in HIBD, potentially via the p38 mitogen‑activated protein kinase signaling pathway.

Apoptosis signal-regulating kinase 1 inhibition in in vivo and in vitro models of pulmonary hypertension

Pulmonary arterial hypertension, group 1 of the pulmonary hypertension disease family, involves pulmonary vascular remodelling, right ventricular dysfunction and cardiac failure. Oxidative stress, through activation of mitogen-activated protein kinases is implicated in these changes. Inhibition of apoptosis signal-regulating kinase 1, an apical mitogen-activated protein kinase, prevented pulmonary arterial hypertension developing in rodent models. Here, we investigate apoptosis signal-regulating kinase 1 in pulmonary arterial hypertension by examining the impact that its inhibition has on the molecular and cellular signalling in established disease. Apoptosis signal-regulating kinase 1 inhibition was investigated in in vivo pulmonary arterial hypertension and in vitro pulmonary hypertension models. In the in vivo model, male Sprague Dawley rats received a single subcutaneous injection of Sugen SU5416 (20 mg/kg) prior to two weeks of hypobaric hypoxia (380 mmHg) followed by three weeks normoxia (Sugen/hypoxic), then animals were either maintained for three weeks on control chow or one containing apoptosis signal-regulating kinase 1 inhibitor (100 mg/kg/day). Cardiovascular measurements were carried out. In the in vitro model, primary cultures of rat pulmonary artery fibroblasts and rat pulmonary artery smooth muscle cells were maintained in hypoxia (5% O₂) and investigated for proliferation, migration and molecular signalling in the presence or absence of apoptosis signal-regulating kinase 1 inhibitor. Sugen/hypoxic animals displayed significant pulmonary arterial hypertension compared to normoxic controls at eight weeks. Apoptosis signal-regulating kinase 1 inhibitor decreased right ventricular systolic pressure to control levels and reduced muscularised vessels in lung tissue. Apoptosis signal-regulating kinase 1 inhibition was found to prevent hypoxia-induced proliferation, migration and cytokine release in rat pulmonary artery fibroblasts and also prevented rat pulmonary artery fibroblast-induced rat pulmonary artery smooth muscle cell migration and proliferation. Apoptosis signal-regulating kinase 1 inhibition reversed pulmonary arterial hypertension in the Sugen/hypoxic rat model. These effects may be a result of intrinsic changes in the signalling of adventitial fibroblast.

Looking for immortality: Review of phytotherapy for stem cell senescence

In this paper, we discussed natural agents with protective effects against stem cell senescence. Different complications have been observed due to stem cell senescence and the most important of them is "Aging". Senescent cells have not normal function and their secretary inflammatory factors induce chronic inflammation in body which causes different pathologies. Stem cell senescence also has been investigated in different diseases or as drug adverse effects. We searched databases such as Embase, Pubmed and Web of Science with keywords "stem cell", "progenitor cell", "satellite", "senescence" and excluded keywords "cancer", "tumor", "malignancy" and "carcinoma" without time limitation until May 2019. Among them we chose 52 articles that have investigated protective effects of natural agents (extracts or molecules) against cellular senescence in different kind of adult stem cells. Most of these studies were in endothelial progenitor cells, hematopoietic stem cells, mesenchymal stem cells, adipose-derived stem cells and few were about other kinds of stem cells. Most studied agents were resveratrol and ginseng which are also commercially available as supplement. Most protective molecular targets were telomerase and anti-oxidant enzymes to preserve genome integrity and reduce senescence-inducing signals. Due to the safe and long history of herbal usage in clinic, phytotherapy can be used for preventing stem cell senescence and their related complication. Resveratrol and ginseng can be the first choice for this aim due to their protective mechanisms in various kinds of stem cells and their long term clinical usage.

Butyrate Inhibits Deoxycholic-Acid-Resistant Colonic Cell Proliferation via Cell Cycle Arrest and Apoptosis: A Potential Pathway Linking Dietary Fiber to Cancer Prevention

SCOPE

Butyrate, an intestinal microbiota metabolite of dietary fiber, exhibits colon cancer preventive effects. In contrast, a high fat intake increases fecal secondary bile acids, such as deoxycholic acid (DCA, a potential cancer promoter), which selectively enrich mutant epithelial cells with an abnormally high resistance to DCA-induced apoptosis in the colon. This study is conducted to test the hypothesis that physiological concentrations of butyrate inhibit DCA-resistant colonic cell proliferation.

METHODS AND RESULTS

With human HCT-116 cells as parental colonic cells, a human DCA-resistant colonic cell line (DCA-RCL) is developed. DCA treatment increases apoptosis and intracellular reactive oxygen species (an apoptotic trigger) at a rate threefold greater in HCT-116 cells than in DCA-RCL cells. Subsequently, 41 apoptosis related genes (including signaling pathways) with greater than onefold (mRNA) change in DCA-RCL cells are identified compared with HCT-116 cells. Moreover, butyrate treatment inhibits DCA-RCL cell proliferation with similar efficacy when compared with HCT116 cells via cellular myelocytomatosis oncogene (c-Myc)/p38 mitogen-activated protein kinase pathway.

CONCLUSION

It is demonstrated that butyrate inhibits DCA-RCL cell proliferation at the cellular and molecular level. These data provide a proof of concept that butyrate can protect against colon carcinogenesis through a specific targeting of DCA-resistant colonic cells.

Apigenin alleviated acetaminophen-induced hepatotoxicity in low protein-fed rats: Targeting oxidative stress, STAT3, and apoptosis signals

Apigenin (API) is a natural flavonoid abundant in fruits and vegetables. The present study was undertaken to evaluate the effect of protein malnutrition (PMN) on acetaminophen (APAP)-induced hepatotoxicity, together with the protective effects of API, in male Wistar albino rats. In total, 64 male rats were divided into eight groups. Silymarin (SIL) (100 mg/kg, PO) as a reference standard and API (50 mg/kg, PO) were given to normal and APAP-induced hepatic injury in low protein-fed rats. The present results revealed that PMN significantly potentiated APAP-induced hepatotoxicity. Interestingly, the administration of SIL and API alleviated the induced damage, as revealed by reduced serum alanine aminotransferase and aspartate aminotransferase activities along with a significant improvement of the histopathological damage. API suppressed inflammatory response by reducing the interleukin-1β level and signal transducer and activator of transcription 3 expressions along with attenuating oxidative stress as shown by a significant reduction in liver contents of malondialdehyde and nitrite/nitrate as well as restoration of hepatic content of reduced glutathione and superoxide dismutase activity. API also counteracted apoptosis through downregulation of caspase-3 expression level. In conclusion, PMN greatly potentiated the hepatotoxic effects of APAP, and API produced a multimechanistic hepatoprotective activity that can be attributed to its antioxidant, anti-inflammatory, and antiapoptotic effects.

Investigating RNA expression profiles altered by nicotinamide mononucleotide therapy in a chronic model of alcoholic liver disease

BACKGROUND

Chronic alcohol consumption is a significant cause of liver disease worldwide. Several biochemical mechanisms have been linked to the initiation and progression of alcoholic liver disease (ALD) such as oxidative stress, inflammation, and metabolic dysregulation, including the disruption of NAD⁺/NADH. Indeed, an ethanol-mediated reduction in hepatic NAD⁺ levels is thought to be one factor underlying ethanol-induced steatosis, oxidative stress, steatohepatitis, insulin resistance, and inhibition of gluconeogenesis. Therefore, we applied a NAD⁺ boosting supplement to investigate alterations in the pathogenesis of early-stage ALD.

METHODS

To examine the impact of NAD⁺ therapy on the early stages of ALD, we utilized nicotinamide mononucleotide (NMN) at 500 mg/kg intraperitoneal injection every other day, for the duration of a Lieber-DeCarli 6-week chronic ethanol model in mice. Numerous strategies were employed to characterize the effect of NMN therapy, including the integration of RNA-seq, immunoblotting, and metabolomics analysis.

RESULTS

Our findings reveal that NMN therapy increased hepatic NAD⁺ levels, prevented an ethanol-induced increase in plasma ALT and AST, and changed the expression of 25% of the genes that were modulated by ethanol metabolism. These genes were associated with a number of pathways including the MAPK pathway. Interestingly, our analysis revealed that NMN treatment normalized Erk1/2 signaling and prevented an induction of Atf3 overexpression.

CONCLUSIONS

These findings reveal previously unreported mechanisms by which NMN supplementation alters hepatic gene expression and protein pathways to impact ethanol hepatotoxicity in an early-stage murine model of ALD. Overall, our data suggest further research is needed to fully characterize treatment paradigms and biochemical implications of NAD⁺-based interventions.

Involvement of p38 MAPK pathway in benzo(a)pyrene-induced human hepatoma cell migration and invasion

The objective of this study was to investigate the potential role of p38 mitogen-activated protein kinases (MAPK) in benzo(a)pyrene (BaP)-induced hepatoma cell migration and invasion. Western blot assay was applied to detect the expression of proteins. qRT-PCR assay was used to measure the expression of mRNA. Wound healing assay and Transwell invasion assay were performed to evaluate cell migratory ability and cell invasive ability, respectively. Our data showed that BaP exposure increased the expression of p-p38 protein in human hepatoma HepG2 cells. Exposure to BaP facilitated HepG2 cell migration and invasion, which could be blocked by p38 MAPK inhibitors. In addition, BaP exposure induced upregulation of MMP9 mRNA expression, which was modulated by p-p38. In conclusion, p38 MAPK pathway was involved in BaP-induced hepatoma cell migration and invasion.

Cerium oxide nanoparticles improve liver regeneration after acetaminophen-induced liver injury and partial hepatectomy in rats

Background and aims

Cerium oxide nanoparticles are effective scavengers of reactive oxygen species and have been proposed as a treatment for oxidative stress-related diseases. Consequently, we aimed to investigate the effect of these nanoparticles on hepatic regeneration after liver injury by partial hepatectomy and acetaminophen overdose.

Methods

All the in vitro experiments were performed in HepG2 cells. For the acetaminophen and partial hepatectomy experimental models, male Wistar rats were divided into three groups: (1) nanoparticles group, which received 0.1 mg/kg cerium nanoparticles i.v. twice a week for 2 weeks before 1 g/kg acetaminophen treatment, (2) N-acetyl-cysteine group, which received 300 mg/kg of N-acetyl-cysteine i.p. 1 h after APAP treatment and (3) partial hepatectomy group, which received the same nanoparticles treatment before partial hepatectomy. Each group was matched with vehicle-controlled rats.

Results

In the partial hepatectomy model, rats treated with cerium oxide nanoparticles showed a significant increase in liver regeneration, compared with control rats. In the acetaminophen experimental model, nanoparticles and N-acetyl-cysteine treatments decreased early liver damage in hepatic tissue. However, only the effect of cerium oxide nanoparticles was associated with a significant increment in hepatocellular proliferation. This treatment also reduced stress markers and increased cell cycle progression in hepatocytes and the activation of the transcription factor NF-κB in vitro and in vivo.

Conclusions

Our results demonstrate that the nanomaterial cerium oxide, besides their known antioxidant capacities, can enhance hepatocellular proliferation in experimental models of liver regeneration and drug-induced hepatotoxicity.

Hepatospecific ablation of p38α MAPK governs liver regeneration through modulation of inflammatory response to CCl4-induced acute injury

Mammalian p38α MAPK (Mitogen-Activated Protein Kinase) transduces a variety of extracellular signals that regulate cellular processes, such as inflammation, differentiation, proliferation or apoptosis. In the liver, depending of the physiopathological context, p38α acts as a negative regulator of hepatocyte proliferation as well as a promotor of inflammatory processes. However, its function during an acute injury, in adult liver, remains uncharacterized. In this study, using mice that are deficient in p38α specifically in mature hepatocytes, we unexpectedly found that lack of p38α protected against acute injury induced by CCl₄ compound. We demonstrated that the hepatoprotective effect alleviated ROS accumulation and shaped the inflammatory response to promote efficient tissue repair. Mechanistically, we provided strong evidence that Ccl2/Ccl5 chemokines were crucial for a proper hepatoprotective response observed secondary to p38α ablation. Indeed, antibody blockade of Ccl2/Ccl5 was sufficient to abrogate hepatoprotection through a concomitant decrease of both inflammatory cells recruitment and antioxidative response that result ultimately in higher liver damages. Our findings suggest that targeting p38α expression and consequently orientating immune response may represent an attractive approach to favor tissue recovery after acute liver injury.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) protected intestinal ischemia-reperfusion injury through JNK and p38/MAPK-dependent pathway for anti-apoptosis

BACKGROUND

Heparin-Binding Epidermal Growth Factor-Like Growth Factor (HB-EGF) is a potent cytoprotective factor in various body systems, including gastrointestinal tract. In this study, we intended to examine whether HB-EGF exerts its protective effects through MAPK dependent anti-apoptosis after intestinal I/R injury.

METHODS

We randomly divided 30 laboratory 30 rats into 5 groups: (A) normal control group, (B) ischemia group with normal saline, (C) I/R group with normal saline, (D) ischemia group with HB-EGF (400 ug/kg), and (E) I/R group with HB-EGF (400 ug/kg). With Western blotting study, we determined JNK and p38/MAPK pathway and caspase-3 activity protein levels using Western analyses.

RESULTS

The JNK phosphorylation protein levels increased after intestinal ischemia or intestinal reperfusion phase, and HB-EGF pre-treatment was significantly decreased in JNK phosphorylation protein levels (p < 0.01). We found that p38 protein levels was increased after intestinal reperfusion phase, and that HB-EGF pre-treatment significantly decreased p38 protein levels (p < 0.01). The expression protein level of caspase 3 was increased after intestinal ischemia or intestinal reperfusion phase. HB-EGF pre-treatment significantly decreased Caspase 3 proteins. (p < 0.01).

CONCLUSION

Our study revealed that pre-treatment of HB-EGF decreased the amount of activity of JNK and p38/MAPK pathway and caspase-3 protein after intestinal I/R injury. These results may further support that the cytoprotective of HB-EGF after I/R injury could be through anti-apoptotic effect of activity of JNK and p38/MAPK pathway.

Differences in Lipopolysaccharides-Induced Inflammatory Response Between Mouse Embryonic Fibroblasts and Bone Marrow-Derived Macrophages

Mouse embryonic fibroblasts (MEFs) are commonly used in research on the molecular mechanism(s) of inflammation because of its good response to inflammatory stimuli. However, the difference in inflammatory reaction between MEFs and macrophages, a classical inflammatory cell type, has not been identified. In this study, we report that both mRNA and protein levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in MEFs upon lipopolysaccharides (LPS) stimulation were significantly lower than those in bone marrow-derived macrophages (BMDMs). MAPK, NF-κB, and IRF3 pathways control the expression and production of inflammatory activated in LPS-stimulated MEFs, but showed different activation patterns in comparison with LPS-stimulated BMDMs. Upon LPS stimulation, activation of the MAPK pathway was slow and remarkably weaker in MEFs than that in BMDMs, whereas more pronounced activation of both NF-κB and IRF3 pathways was observed in MEFs compared to BMDMs. This difference in the activation of MAPK, NF-κB, and IRF3 pathways may result in different production of IL-6 and TNF-α between MEFs and BMDMs. We further revealed that substantial differences in more additional inflammatory response-related cytokines exist between LPS-stimulated MEFs and BMDMs. In conclusion, MEFs exhibit good responsiveness to LPS as a target cell for inflammation-related research. However, MEFs cannot replace macrophages because of substantial differences in their inflammatory reactivity.

p38α deficiency restrains liver regeneration after partial hepatectomy triggering oxidative stress and liver injury

p38α MAPK negatively regulates the G₁/S and G₂/M cell cycle transitions. However, liver-specific p38α deficiency impairs cytokinesis and reduces hepatocyte proliferation during cirrhosis and aging in mice. In this work, we have studied how p38α down-regulation affects hepatocyte proliferation after partial hepatectomy, focusing on mitotic progression, cytokinesis and oxidative stress. We found that p38α deficiency triggered up-regulation of cyclins A1, B1, B2, and D1 under basal conditions and after hepatectomy. Moreover, p38α-deficient hepatocytes showed enhanced binucleation and increased levels of phospho-histone H3 but impaired phosphorylation of MNK1 after hepatectomy. The recovery of liver mass was transiently delayed in mice with p38α-deficient hepatocytes vs wild type mice. We also found that p38α deficiency caused glutathione oxidation in the liver, increased plasma aminotransferases and lactate dehydrogenase activities, and decreased plasma protein levels after hepatectomy. Interestingly, p38α silencing in isolated hepatocytes markedly decreased phospho-MNK1 levels, and silencing of either p38α or Mnk1 enhanced binucleation of hepatocytes in culture. In conclusion, p38α deficiency impairs mitotic progression in hepatocytes and restrains the recovery of liver mass after partial hepatectomy. Our results also indicate that p38α regulates cytokinesis by activating MNK1 and redox modulation.

Resistance to lysosomotropic drugs used to treat kidney and breast cancers involves autophagy and inflammation and converges in inducing CXCL5

Lysosomotropic agents such as sunitinib, lapatinib, and chloroquine belong to a drug family that is being used more frequently to treat advanced cancers. Sunitinib is standard care for metastatic renal cell carcinomas (mRCC) and lapatinib is used for trastuzumab/pertuzumab-refractory cancers. However, patients ineluctably relapse with a delay varying from a few months to a few years. To improve reactivity prior to relapse it is essential to identify the mechanisms leading to such variability. We showed previously that sunitinib became sequestered in lysosomes because of its basic pKa.

Methods: Modifications to gene expression in response to sunitinib and in sunitinib resistant cells were analyzed by transcriptomic and proteomic analysis. ROS production was evaluated by FACS. Nuclear Factor kappa B (NFkB)-dependent transcriptional regulation of inflammatory gene expression was evaluated with a reporter gene. Correlation of CXCL5 with survival was analyzed with an online available data base (TCGA) and using a cohort of patients enrolled in the SUVEGIL clinical trial (NCT00943839).

Results: We now show that sunitinib sequestration in lysosomes induced an incomplete autophagic process leading to activation of the NFkB inflammatory pathway. We defined a subset of inflammatory cytokines that were up-regulated by the drug either after an acute or chronic stimulus. One of the most up-regulated genes in sunitinib-resistant cells was the CXCL5 cytokine. CXCL5 was also induced in RCC by chloroquine and in a model of HER2 positive breast cancer cell lines after acute or chronic treatment with lapatinib. CXCL5 correlated to shorter survival in RCC and to the most aggressive forms of breast cancers. The levels of CXCL5 present in the plasma of patients treated with sunitinib were predictive of the efficacy of sunitinib but not of the VEGF-directed antibody bevacizumab.

Conclusion: This translational study identified CXCL5 as a biomarker of efficacy of lysosomotropic drugs, a potential asset for personalized medicine.

A prospect of cell immortalization combined with matrix microenvironmental optimization strategy for tissue engineering and regeneration

Cellular senescence is a major hurdle for primary cell-based tissue engineering and regenerative medicine. Telomere erosion, oxidative stress, the expression of oncogenes and the loss of tumor suppressor genes all may account for the cellular senescence process with the involvement of various signaling pathways. To establish immortalized cell lines for research and clinical use, strategies have been applied including internal genomic or external matrix microenvironment modification. Considering the potential risks of malignant transformation and tumorigenesis of genetic manipulation, environmental modification methods, especially the decellularized cell-deposited extracellular matrix (dECM)-based preconditioning strategy, appear to be promising for tissue engineering-aimed cell immortalization. Due to few review articles focusing on this topic, this review provides a summary of cell senescence and immortalization and discusses advantages and limitations of tissue engineering and regeneration with the use of immortalized cells as well as a potential rejuvenation strategy through combination with the dECM approach.

Skin anti-inflammatory activity of rose petal extract (Rosa gallica) through reduction of MAPK signaling pathway

The aim of this study was to investigate the skin anti-inflammatory activity of rose petal extract (RPE) and the mechanisms underlying this phenomenon. Recently, flowers have been considered as dietary resources owing to their biological activities, such as inhibition of nephritis and hemorrhoids. The Rosa plant exerts various biological functions, including antioxidant and anti-microbiological activities. Herein, we confirmed the skin anti-inflammatory activity of RPE upon solar UV (sUV) exposure. RPE reduced sUV-induced COX-2 expression as well as expressions of several cytokines. Activation of MKK4-JNK, MEK-ERK, and MKK3-p38 signaling pathways, which are associated with cytokine production, was also attenuated by RPE treatment. We hypothesized these RPE-induced changes are because of its antioxidant activity, because RPE displayed drastic radical scavenging and oxygen radical absorbance capacity (ORAC). Furthermore, high anthocyanins, polyphenols, and flavonoids contents were found in RPE. Hence, these results indicated the skin anti-inflammatory activity of RPE is because of antioxidant activity.

Hydrogen sulfide alleviates uranium-induced rat hepatocyte cytotoxicity via inhibiting Nox4/ROS/p38 MAPK pathway

As a gasotransmitter, hydrogen sulfide (H₂ S) plays a crucial role in regulating the signaling pathway mediated by oxidative stress. The purpose of this study was to investigate the protective effects of H ₂ S on uranium-induced rat hepatocyte cytotoxicity. Primary hepatocytes were isolated and cultured from Sprague Dawley rat liver tissues. After pretreating with sodium hydrosulfide (an H ₂ S donor) for 1 hour (or GKT-136901 for 30 minutes), hepatocytes were treated by uranyl acetate for 24 hours. Cell viability, reactive oxygen species (ROS), malondialdehyde (MDA), NADPH oxidase 4 (Nox4), and p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation were respectively determined. The effects of direct inhibition of Nox4 expression by GKT-136901 (a Nox4 inhibitor) on ROS and phospho-p38 MAPK levels were examined in uranium-treated hepatocytes. The results implicate that H ₂ S can afford protection of rat hepatocytes against uranium-induced adverse effects through attenuating oxidative stress via prohibiting Nox4/ROS/p38 MAPK signaling.

Lactobacillus brevis 23017 Relieves Mercury Toxicity in the Colon by Modulation of Oxidative Stress and Inflammation Through the Interplay of MAPK and NF-κB Signaling Cascades

Aims: Lactobacillus strains have protective effects against heavy metals while relieving oxidative stress and modulating the immune response. Mechanisms that ameliorate heavy metal toxicity and the relationship between probiotics and gut barrier protection in the process of heavy metal pathogenesis was poorly understood. Methods and Results: In this study, Lactobacillus brevis 23017 (LAB, L. brevis 23017), a selected probiotics strain with strong mercury binding capacities, was applied to evaluate the efficiency against mercury toxicity in a mouse model. Histopathological results along with HE stains show that L. brevis 23017 protects the integrity of the small intestinal villus, which slows weight loss in response to Hg exposure. The qRT-PCR results demonstrate that L. brevis 23017 maintains a normal mucosal barrier via modulation of tight junction proteins. Importantly, the present study demonstrates that L. brevis 23017 effectively ameliorates injury of the small intestine by reducing intestinal inflammation and alleviating oxidative stress in animal models. Moreover, L. brevis 23017 blocks oxidative stress and inflammation through MAPK and NF-κB pathways, as shown by western blot. Conclusions: Together, these results reveal that L. brevis 23017 may have applications in the prevention and treatment of oral Hg exposure with fermented functional foods by protecting gut health in daily life.

Bavachinin Induces Oxidative Damage in HepaRG Cells through p38/JNK MAPK Pathways

Drug-induced liver injury is one of the main causes of drug non-approval and drug withdrawal by the Food and Drug Administration (FDA). Bavachinin (BVC) is a natural product derived from the fruit of the traditional Chinese herb Fructus Psoraleae (FP). There have been reports of acute liver injury following the administration of FP and its related proprietary medicines. To explore BVC hepatotoxicity and its mechanisms, we used the HepaRG cell line. In our recent research, we showed that BVC induces HepaRG cell death, mainly via BVC-induced oxidative damage. The formation of ROS is closely related to the activation of the stress-activated kinases, JNK and p38, while SP600125 (SP, JNK inhibitor) and SB203580 (SB, p38 inhibitor) pretreatment inhibited the generation of ROS. On the other hand, N-acetylcysteine (NAC) pretreatment prevented the phosphorylation of p38 but not that of JNK. Taken together, these data reveal that BVC induces HepaRG cell death via ROS and the JNK/p38 signaling pathways.

Interleukin-17A participates in podocyte injury by inducing IL-1β secretion through ROS-NLRP3 inflammasome-caspase-1 pathway

Studies show that the Th17/IL-17A axis plays an important role in the pathogenesis of kidney diseases. Previously, we also showed that IL-17A may play a role in the pathogenesis of primary nephrotic syndrome; however, the underlying mechanism(s) is unclear. The aim of this study was to explore the molecular mechanism of IL-17A-inducing podocyte injury in vitro. In this study, the NLRP3 inflammasome activation and the morphology of podocytes were detected by Western blot and immunofluorescence. The results showed that podocytes persistently expressed IL-17A receptor and that NLRP3 inflammasome in these cells was activated upon exposure to IL-17A. Also, activity of caspase-1 and secretion of IL-1β increased in the presence of IL-17A. In addition, IL-17A disrupted podocyte morphology by decreasing expression of podocin and increasing expression of desmin. Blockade of intracellular ROS or inhibition of caspase-1 prevented activation of the NLRP3 inflammasome, thereby restoring podocyte morphology. Taken together, the results suggest that IL-17A induces podocyte injury by activating the NLRP3 inflammasome and IL-1β secretion and contributes to disruption of the kidney's filtration system.

A reactive oxygen species activation mechanism contributes to Sophoridine-induced apoptosis in rat liver BRL-3A cells

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora alopecuroides L., a traditional Chinese herb, has been widely used to treat numerous diseases throughout China. Quinolizidine alkaloids were identified as active components in Sophora alopecuroides L., and Sophoridine (SRI) is the major component in the Quinolizidine alkaloids.

AIM OF THE STUDY

To investigate the toxic effects of SRI in rat liver BRL-3A cells and to explore potential ROS-related mechanisms.

MATERIALS AND METHODS

Cell viability, cytotoxicity, apoptosis, intracellular generation of ROS, GSH/GSSG ratio and levels of proteins in mitochondria apoptosis pathway were analyzed.

RESULTS

Our data indicated that SRI could suppress BRL-3A cells viability in a concentration- and time-dependent manner and increase cytotoxicity, ROS accumulation and cell apoptosis in a concentration-dependent manner. Expressions and activities of apoptotic related proteins were upregulated, whereas expression of Bcl-2 was downregulated after treatment. Furthermore, level of H₂O₂ was increased, whereas level of Superoxide was not changed after treatment. Moreover, the antioxidant N-acetylcysteine reversed SRI-induced apoptosis and ROS accumulation.

CONCLUSION

Our data suggest that SRI promotes rat liver BRL-3A cells apoptosis by increasing intracellular ROS accumulation.

Reactive Oxygen Species and Mitochondrial Dynamics: The Yin and Yang of Mitochondrial Dysfunction and Cancer Progression

Mitochondria are organelles with a highly dynamic ultrastructure maintained by a delicate equilibrium between its fission and fusion rates. Understanding the factors influencing this balance is important as perturbations to mitochondrial dynamics can result in pathological states. As a terminal site of nutrient oxidation for the cell, mitochondrial powerhouses harness energy in the form of ATP in a process driven by the electron transport chain. Contemporaneously, electrons translocated within the electron transport chain undergo spontaneous side reactions with oxygen, giving rise to superoxide and a variety of other downstream reactive oxygen species (ROS). Mitochondrially-derived ROS can mediate redox signaling or, in excess, cause cell injury and even cell death. Recent evidence suggests that mitochondrial ultrastructure is tightly coupled to ROS generation depending on the physiological status of the cell. Yet, the mechanism by which changes in mitochondrial shape modulate mitochondrial function and redox homeostasis is less clear. Aberrant mitochondrial morphology may lead to enhanced ROS formation, which, in turn, may deteriorate mitochondrial health and further exacerbate oxidative stress in a self-perpetuating vicious cycle. Here, we review the latest findings on the intricate relationship between mitochondrial dynamics and ROS production, focusing mainly on its role in malignant disease.