4-hydroxysesamin protects rat with right ventricular failure due to pulmonary hypertension by inhibiting JNK/p38 MAPK signaling.

The specific mechanism of 4-hydroxysesamin (4-HS), a modification of Sesamin, on right ventricular failure due to pulmonary hypertension (PH) is ominous. By creating a rat model of PH in vivo and a model of pulmonary artery smooth muscle cell (PASMC) hypoxia and inflammation in vitro, the current work aimed to investigate in depth the molecular mechanism of the protective effect of 4-HS. In an in vitro model of hypoxia PASMC, changes in cell proliferation and inflammatory factors were detected after treatment with 4-HS, followed by changes in the JNK/p38 MAPK signaling pathway as detected by Western blot signaling pathway. The findings demonstrated that 4-HS was able to minimize PASMC cell death, block the JNK/p38 MAPK signaling pathway, and resist the promoting effect of hypoxia on PASMC cell proliferation. Following that, we found that 4-HS could both mitigate the right ventricular damage brought on by MCT and had a protective impact on rats Monocrotaline (MCT)-induced PH in in vivo investigations. The key finding of this study is that 4-HS may protect against PH by inhibiting the JNK/p38 MAPK signaling pathway.

Oxidative stress promotes liver fibrosis by modulating the microRNA-144 and SIN3A-p38 pathways in hepatic stellate cells.

Background & Aims: Reactive oxygen species (ROS) act as modulators triggering cellular dysfunctions and organ damage including liver fibrosis in which hepatic stellate cell (HSC) activation plays a key role. Previous studies suggest that microRNA-144 (miR-144) acts as a pro-oxidant molecule; however, whether and how miR-144 affects HSC activation and liver fibrosis remain unknown. Methods: Carbon tetrachloride (CCl4) and bile duct ligation (BDL)-induced experimental liver fibrosis models were used. Hepatic miR-144 expression was analyzed by miRNA in situ hybridization with RNAscope probe. The in vivo effects of silencing or overexpressing miR-144 were examined with an adeno-associated virus 6 (AAV6) carrying miR-144 inhibitor or mimics in fibrotic mouse experimental models. Results: In this study, we demonstrated that ROS treatment significantly upregulated miR-144 in HSCs, which further promoted HSC activation in vitro. Interestingly, miR-144 was preferentially elevated in HSCs of experimental liver fibrosis in mice and in human liver fibrotic tissues. Furthermore, in vivo loss or gain-of-function experiments via AAV6 carrying miR-144 antagomir or agomir revealed that blockade of miR-144 in HSCs mitigated, while overexpression of miR-144 in HSCs accelerated the development of experimental liver fibrosis. Mechanistically, SIN3 transcription regulator family member A (SIN3A), a transcriptional repressor, was identified to be the target of miR-144 in HSCs. MiR-144 downregulated Sin3A, and in line with this result, specific knockdown of Sin3a in HSCs remarkedly activated p38 MAPK signaling pathway to promote HSC activation, eventually exacerbating liver fibrosis. Conclusions: Oxidative stress-driven miR-144 fuels HSC activation and liver fibrogenesis by limiting the SIN3A-p38 axis. Thus, a specific inhibition of miR-144 in HSCs could be a novel therapeutic strategy for the treatment of liver fibrosis.

Amyloid Beta Leads to Decreased Acetylcholine Levels and Non-Small Cell Lung Cancer Cell Survival via a Mechanism That Involves p38 Mitogen-Activated Protein Kinase and Protein Kinase C in a p53-Dependent and -Independent Manner.

Several studies have shown an inverse correlation between the likelihood of developing a neurodegenerative disorder and cancer. We previously reported that the levels of amyloid beta (Aß), at the center of Alzheimer's disease pathophysiology, are regulated by acetylcholinesterase (AChE) in non-small cell lung cancer (NSCLC). Here, we examined the effect of Aß or its fragments on the levels of ACh in A549 (p53 wild-type) and H1299 (p53-null) NSCLC cell media. ACh levels were reduced by cell treatment with Aß 1-42, Aß 1-40, Aß 1-28, and Aß 25-35. AChE and p53 activities increased upon A549 cell treatment with Aß, while knockdown of p53 in A549 cells increased ACh levels, decreased AChE activity, and diminished the Aß effects. Aß increased the ratio of phospho/total p38 MAPK and decreased the activity of PKC. Inhibiting p38 MAPK reduced the activity of p53 in A549 cells and increased ACh levels in the media of both cell lines, while opposite effects were found upon inhibiting PKC. ACh decreased the activity of p53 in A549 cells, decreased p38 MAPK activity, increased PKC activity, and diminished the effect of Aß on those activities. Moreover, the negative effect of Aß on cell viability was diminished by cell co-treatment with ACh.

Mycobacterium avium paratuberculosis Infection Suppresses Vitamin D Activation and Cathelicidin Production in Macrophages through Modulation of the TLR2-Dependent p38/MAPK-CYP27B1-VDR-CAMP Axis.

BACKGROUND: Vitamin D plays a vital role in modulating both innate and adaptive immune systems. Therefore, vitamin D deficiency has been associated with higher levels of autoimmune response and increased susceptibility to infections. CYP27B1 encodes a member of the cytochrome P450 superfamily of enzymes. It is instrumental in the conversion of circulating vitamin D (calcifediol) to active vitamin D (calcitriol). This is a crucial step for macrophages to express Cathelicidin Anti-microbial Peptide (CAMP), an anti-bacterial factor released during the immune response. Our recent study indicated that a Crohn's disease (CD)-associated pathogen known as Mycobacterium avium paratuberculosis (MAP) decreases vitamin D activation in macrophages, thereby impeding cathelicidin production and MAP infection clearance. The mechanism by which MAP infection exerts these effects on the vitamin D metabolic axis remains elusive. METHODS: We used two cell culture models of THP-1 macrophages and Caco-2 monolayers to establish the effects of MAP infection on the vitamin D metabolic axis. We also tested the effects of Calcifediol, Calcitriol, and SB203580 treatments on the relative expression of the vitamin D metabolic genes, oxidative stress biomarkers, and inflammatory cytokines profile. RESULTS: In this study, we found that MAP infection interferes with vitamin D activation inside THP-1 macrophages by reducing levels of CYP27B1 and vitamin D receptor (VDR) gene expression via interaction with the TLR2-dependent p38/MAPK pathway. MAP infection exerts its effects in a time-dependent manner, with the maximal inhibition observed at 24 h post-infection. We also demonstrated the necessity to have toll-like receptor 2 (TLR2) for MAP infection to influence CYP27B1 and CAMP expression, as TLR2 gene knockdown resulted in an average increase of 7.78 ± 0.88 and 13.90 ± 3.5 folds in their expression, respectively. MAP infection also clearly decreased the levels of p38 phosphorylation and showed dependency on the p38/MAPK pathway to influence the expression of CYP27B1, VDR, and CAMP which was evident by the average fold increase of 1.93 ± 0.28, 1.86 ± 0.27, and 6.34 ± 0.51 in their expression, respectively, following p38 antagonism. Finally, we showed that calcitriol treatment and p38/MAPK blockade reduce cellular oxidative stress and inflammatory markers in Caco-2 monolayers following macrophage-mediated MAP infection. CONCLUSIONS: This study characterized the primary mechanism by which MAP infection leads to diminished levels of active vitamin D and cathelicidin in CD patients, which may explain the exacerbated vitamin D deficiency state in these cases.

17ß-Estradiol (E2) Activates Matrix Mineralization through Genomic/Nongenomic Pathways in MC3T3-E1 Cells.

Estrogen plays an important role in osteoporosis prevention. We herein report the possible novel signaling pathway of 17ß-estradiol (E2) in the matrix mineralization of MC3T3-E1, an osteoblast-like cell line. In the culture media-containing stripped serum, in which small lipophilic molecules such as steroid hormones including E2 were depleted, matrix mineralization was significantly reduced. However, the E2 treatment induced this. The E2 effects were suppressed by ICI182,780, the estrogen receptor (ER)α, and the ERß antagonist, as well as their mRNA knockdown, whereas Raloxifene, an inhibitor of estrogen-induced transcription, and G15, a G-protein-coupled estrogen receptor (GPER) 1 inhibitor, had little or no effect. Furthermore, the E2-activated matrix mineralization was disrupted by PMA, a PKC activator, and SB202190, a p38 MAPK inhibitor, but not by wortmannin, a PI3K inhibitor. Matrix mineralization was also induced by the culture media from the E2-stimulated cell culture. This effect was hindered by PMA or heat treatment, but not by SB202190. These results indicate that E2 activates the p38 MAPK pathway via ERs independently from actions in the nucleus. Such activation may cause the secretion of certain signaling molecule(s), which inhibit the PKC pathway. Our study provides a novel pathway of E2 action that could be a therapeutic target to activate matrix mineralization under various diseases, including osteoporosis.

Utilizing network pharmacology, molecular docking, and animal models to explore the therapeutic potential of the WenYang FuYuan recipe for cerebral ischemia-reperfusion injury through AGE-RAGE and NF-κB/p38MAPK signaling pathway modulation.

BACKGROUND: Stroke is a debilitating condition with high morbidity, disability, and mortality that significantly affects the quality of life of patients. In China, the WenYang FuYuan recipe is widely used to treat ischemic stroke. However, the underlying mechanism remains unknown, so exploring the potential mechanism of action of this formula is of great practical significance for stroke treatment. OBJECTIVE: This study employed network pharmacology, molecular docking, and in vivo experiments to clarify the active ingredients, potential targets, and molecular mechanisms of the WenYang FuYuan recipe in cerebral ischemia-reperfusion injury, with a view to providing a solid scientific foundation for the subsequent study of this recipe. MATERIALS AND METHODS: Active ingredients of the WenYang FuYuan recipe were screened using the traditional Chinese medicine systems pharmacology database and analysis platform. Network pharmacology approaches were used to explore the potential targets and mechanisms of action of the WenYang FuYuan recipe for the treatment of cerebral ischemia-reperfusion injury. The Middle Cerebral Artery Occlusion/Reperfusion 2 h Sprague Dawley rat model was prepared, and TTC staining and modified neurological severity score were applied to examine the neurological deficits in rats. HE staining and Nissl staining were applied to examine the pathological changes in rats. Immunofluorescence labeling and Elisa assay were applied to examine the expression levels of certain proteins and associated factors, while qRT-PCR and Western blotting were applied to examine the expression levels of linked proteins and mRNAs in disease-related signaling pathways. RESULTS: We identified 62 key active ingredients in the WenYang FuYuan recipe, with 222 highly significant I/R targets, forming 138 pairs of medication components and component-targets, with the top five being Quercetin, Kaempferol, Luteolin, ß-sitosterol, and Stigmasterol. The key targets included TP53, RELA, TNF, STAT1, and MAPK14 (p38MAPK). Targets related to cerebral ischemia-reperfusion injury were enriched in chemical responses, enzyme binding, endomembrane system, while enriched pathways included lipid and atherosclerosis, fluid shear stress and atherosclerosis, AGE-RAGE signaling in diabetic complications. In addition, the main five active ingredients and targets in the WenYang FuYuan recipe showed high binding affinity (e.g. Stigmasterol and MAPK14, total energy <-10.5 Kcal/mol). In animal experiments, the WenYang FuYuan recipe reduced brain tissue damage, increased the number of surviving neurons, and down-regulated S100ß and RAGE protein expression. Moreover, the relative expression levels of key targets such as TP53, RELA and p38MAPK mRNA were significantly down-regulated in the WenYang FuYuan recipe group, and serum IL-6 and TNF-a factor levels were reduced. After WenYang FuYuan recipe treatment, the AGE-RAGE signaling pathway and downstream NF-kB/p38MAPK signaling pathway-related proteins were significantly modulated. CONCLUSION: This study utilized network pharmacology, molecular docking, and animal experiments to identify the potential mechanism of the WenYang FuYuan recipe, which may be associated with the regulation of the AGE-RAGE signaling pathway and the inhibition of target proteins and mRNAs in the downstream NF-kB/p38MAPK pathway.

Overexpression of GPX2 gene regulates the development of porcine preadipocytes and skeletal muscle cells through MAPK signaling pathway.

Glutathione peroxidase 2 (GPX2) is a selenium-dependent enzyme and protects cells against oxidative damage. Recently, GPX2 has been identified as a candidate gene for backfat and feed efficiency in pigs. However, it is unclear whether GPX2 regulates the development of porcine preadipocytes and skeletal muscle cells. In this study, adenoviral gene transfer was used to overexpress GPX2. Our findings suggest that overexpression of GPX2 gene inhibited proliferation of porcine preadipocytes. And the process is accompanied by the reduction of the p-p38. GPX2 inhibited adipogenic differentiation and promoted lipid degradation, while ERK1/2 was reduced and p-p38 was increased. Proliferation of porcine skeletal muscle cells was induced after GPX2 overexpression, was accompanied by activation in JNK, ERK1/2, and p-p38. Overexpression methods confirmed that GPX2 has a promoting function in myoblastic differentiation. ERK1/2 pathway was activated and p38 was suppressed during the process. This study lays a foundation for the functional study of GPX2 and provides theoretical support for promoting subcutaneous fat reduction and muscle growth.

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway.

Malignant insulinoma is an extremely rare type of functioning pancreatic neuroendocrine tumour with a high degree of malignancy and a high incidence of metastasis. However, it is still unclear how malignant insulinomas develop and metastasize. Serum amyloid P component (SAP), a member of the pentraxin protein family, is an acute-phase protein secreted by liver cells. The role of SAP in insulinoma and the related mechanism are still unknown. To determine the effect of SAP on insulinoma, we crossed Rip1-Tag2 mice, which spontaneously develop insulinoma, and SAP knockout (KO) mice to generate Rip1-Tag2;SAP-/- mice. We found that SAP deletion significantly promoted the growth, invasion and metastasis of malignant insulinoma through C-X-C motif chemokine ligand 12 (CXCL12) secreted by cancer-associated fibroblasts (CAFs). Further study showed that SAP deletion promoted CXCL12 secretion by CAFs through the CXCR4/p38/ERK signalling pathway. These findings reveal a novel role and mechanism of SAP in malignant insulinoma and provide direct evidence that SAP may be a therapeutic agent for this disease.

MicroRNA-671-5p regulates the inflammatory response of periodontal ligament stem cells via the DUSP8/p38 MAPK pathway.

BACKGROUND: MicroRNAs are differentially expressed in periodontitis tissues. They are involved in cellular responses to inflammation and can be used as markers for diagnosing periodontitis. Microarray analysis showed that the expression level of microRNA-671-5p in periodontal tissues of patients with periodontitis was increased. In this study, we investigated the mechanism of action of microRNA-671-5p in human periodontal ligament stem cells (hPDLSCs) under inflammatory conditions. METHODS AND RESULTS: HPDLSCs were treated with lipopolysaccharide (LPS) to establish an inflammation model. The cell survival rate was determined using the cell counting kit-8 (CCK8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the expression of microRNA-671-5p and dual-specificity phosphatase (DUSP) 8 proteins, respectively, Interleukin (IL)-6, IL-1ß, and tumor necrosis factor (TNF)-α were detected using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter system was employed to determine the relationship between micoRNA-671-5p and DUSP8 expression. Activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway was confirmed using western blot analysis. Following the treatment of hPDLSCs with LPS, the expression levels of microRNA-671-5p in hPDLSCs were increased, cell viability decreased, and the expression of inflammatory factors displayed an increasing trend. MicroRNA-671-5p targets and binds to DUSP8. Silencing microRNA-671-5p or overexpressing DUSP8 can improve cell survival rate and reduce inflammatory responses. When DUSP8 was overexpressed, the expression of p-p38 was reduced. CONCLUSIONS: microRNA-671-5p targets DUSP8/p38 MAPK pathway to regulate LPS-induced proliferation and inflammation in hPDLSCs.

Identification of triciribine as a novel myeloid cell differentiation inducer.

Differentiation therapy using all-trans retinoic acid (ATRA) for acute promyelocytic leukemia (APL) is well established. However, because the narrow application and tolerance development of ATRA need to be improved, we searched for another efficient myeloid differentiation inducer. Kinase activation is involved in leukemia biology and differentiation block. To identify novel myeloid differentiation inducers, we used a Kinase Inhibitor Screening Library. Using a nitroblue tetrazolium dye reduction assay and real-time quantitative PCR using NB4 APL cells, we revealed that, PD169316, SB203580, SB202190 (p38 MAPK inhibitor), and triciribine (TCN) (Akt inhibitor) potently increased the expression of CD11b. We focused on TCN because it was reported to be well tolerated by patients with advanced hematological malignancies. Nuclear/cytoplasmic (N/C) ratio was significantly decreased, and myelomonocytic markers (CD11b and CD11c) were potently induced by TCN in both NB4 and acute myeloid leukemia (AML) M2 derived HL-60 cells. Western blot analysis using NB4 cells demonstrated that TCN promoted ERK1/2 phosphorylation, whereas p38 MAPK phosphorylation was not affected, suggesting that activation of the ERK pathway is involved in TCN-induced differentiation. We further examined that whether ATRA may affect phosphorylation of ERK and p38, and found that there was no obvious effect, suggesting that ATRA induced differentiation is different from TCN effect. To reveal the molecular mechanisms involved in TCN-induced differentiation, we performed microarray analysis. Pathway analysis using DAVID software indicated that "hematopoietic cell lineage" and "cytokine-cytokine receptor interaction" pathways were enriched with high significance. Real-time PCR analysis demonstrated that components of these pathways including IL1ß, CD3D, IL5RA, ITGA6, CD44, ITGA2B, CD37, CD9, CSF2RA, and IL3RA, were upregulated by TCN-induced differentiation. Collectively, we identified TCN as a novel myeloid cell differentiation inducer, and trials of TCN for APL and non-APL leukemia are worthy of exploration in the future.

D-arabinose induces cell cycle arrest by promoting autophagy via p38 MAPK signaling pathway in breast cancer.

Breast cancer patients often have a poor prognosis largely due to lack of effective targeted therapy. It is now well established that monosaccharide enhances growth retardation and chemotherapy sensitivity in tumor cells. We investigated whether D-arabinose has capability to restrict the proliferation of tumor cells and its mechanism. Here, we report that D-arabinose induced cytotoxicity is modulated by autophagy and p38 MAPK signaling pathway in breast cancer cell lines. The proliferation of cells was evaluated by CCK-8 and Colony formation assay. The distribution of cells in cell cycle phases was analyzed by flow cytometry. Cell cycle, autophagy and MAPK signaling related proteins were detected by western blotting. Mouse xenograft model was used to evaluate the efficacy of D-arabinose in vivo. The proliferation of cells was dramatically inhibited by D-arabinose exposure in a dose-dependent manner, which was relevant to cell cycle arrest, as demonstrated by G2/M cell cycle restriction and ectopic expression of cell cycle related proteins. Mechanistically, we further identified that D-arabinose is positively associated with autophagy and the activation of the p38 MAPK signaling in breast cancer. In contrast, 3-Ma or SB203580, the inhibitor of autophagy or p38 MAPK, reversed the efficacy of D-arabinose. Additionally, D-arabinose in vivo treatment could significantly inhibit xenograft growth of breast cancer cells. Our findings were the first to reveal that D-arabinose triggered cell cycle arrest by inducing autophagy through the activation of p38 MAPK signaling pathway in breast cancer cells.

HIF-1α-dependent upregulation of angiogenic factors by mechanical stimulation in retinal pigment epithelial cells.

Mechanical stimulation as a mimic of drusen formation in the eye increases the expression of angiogenic factors in retinal pigment epithelial (RPE) cells, but the underlying molecular mechanisms remain unclear. We investigated and characterized the effects of mechanical stimulation on the expression of angiogenic factors in RPE cells both in vitro and in a mouse model. Mechanical stimulation increased the expression of vascular endothelial growth factor (VEGF, encoded by VEGFA) and other angiogenesis-related genes in cultured RPE1 cells. The presence of hypoxia-inducible factor 1α (HIF-1α, encoded by HIF1A) was also increased, and both knockdown of HIF-1α and treatment with the HIF-1α inhibitor CAY10585 attenuated the effect of mechanical stimulation on angiogenesis factor gene expression. Signaling by the tyrosine kinase SRC and p38 mitogen-activated protein kinase was involved in HIF-1α activation and consequent angiogenesis-related gene expression induced by mechanical stimulation. Our results suggest that SRC-p38 and HIF-1α signaling are involved in the upregulation of angiogenic factors in RPE cells by mechanical stimulation. Such in vivo suppression of upregulated expression of angiogenesis-related genes by pharmacological inhibitors of HIF-1α suggests a new potential approach to the treatment of age-related macular degeneration.

Increasing expression of dual-specificity phosphatase 12 mitigates oxygen-glucose deprivation/reoxygenation-induced neuronal apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway.

Dual-specificity phosphatase 12 (DUSP12) is abnormally expressed under various pathological conditions and plays a crucial role in the pathological progression of disorders. However, the role of DUSP12 in cerebral ischaemia/reperfusion injury has not yet been investigated. This study explored the possible link between DUSP12 and cerebral ischaemia/reperfusion injury using an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Marked decreases in DUSP12 levels have been observed in cultured neurons exposed to OGD/R. DUSP12-overexpressed neurons were resistant to OGD/R-induced apoptosis and inflammation, whereas DUSP12-deficient neurons were vulnerable to OGD/R-evoked injuries. Further investigation revealed that DUSP12 overexpression or deficiency affects the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in neurons under OGD/R conditions. Moreover, blockade of ASK1 diminished the regulatory effect of DUSP12 deficiency on JNK and p38 MAPK activation. In addition, DUSP12-deficiency-elicited effects exacerbating neuronal OGD/R injury were reversed by ASK1 blockade. In summary, DUSP12 protects against neuronal OGD/R injury by reducing apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway. These findings imply a neuroprotective function for DUSP12 in cerebral ischaemia/reperfusion injury.

Retinoprotective Effect of SkQ1, Visomitin Eye Drops, Is Associated with Suppression of P38 MAPK and ERK1/2 Signaling Pathways Activity.

Visomitin eye drops are the first and, so far, the only drug based on SkQ1 - the mitochondria-targeted antioxidant 10-(6'-plastoquinonyl) decyltriphenylphosphonium, developed in the laboratories of Moscow State University under the leadership of Academician V. P. Skulachev. SkQ1 is considered as a potential tool to combat the aging program. We have previously shown that it is able to prevent and/or suppress development of all manifestations of accelerated senescence in OXYS rats, including retinopathy, similar to the age-related macular degeneration (AMD). Here, we assessed the effect of Visomitin instillations on progression of the AMD-like pathology and p38 MAPK and ERK1/2 activity in the OXYS rat retina (from the age of 9 to 12 months). Wistar and OXYS rats treated with placebo (composition identical to Visomitin with the exception of SkQ1) were used as controls. Ophthalmological examination showed that in the OXYS rats receiving placebo, retinopathy progressed and severity of clinical manifestations did not differ from the intact OXYS rats. Visomitin suppressed progression of the AMD-like pathology in the OXYS rats and significantly improved structural and functional parameters of the retinal pigment epithelium cells and state of microcirculation in the choroid, which, presumably, contributed to preservation of photoreceptors, associative and ganglion neurons. It was found that the activity of p38 MAPK and ERK1/2 in the retina of 12-month-old OXYS rats is higher than that of the Wistar rats of the same age, as indicated by the increased content of phosphorylated forms of p38 MAPK and ERK1/2 and their target protein tau (at position T181 and S396). Visomitin decreased phosphorylation of p38 MAPK, ERK1/2, and tau indicating suppression of activity of these MAPK signaling cascades. Thus, Visomitin eye drops are able to suppress progression of the AMD-like pathology in the OXYS rats and their effect is associated with the decrease in activity of the MAPK signaling cascades.

A diet of oxidative stress-adapted bacteria improves stress resistance and lifespan in C. elegans via p38-MAPK.

Organisms across taxa face stresses including variable temperature, redox imbalance, and xenobiotics. Successfully responding to stress and restoring homeostasis are crucial for survival. Aging is associated with a decreased stress response and alterations in the microbiome, which contribute to disease development. Animals and their microbiota share their environment; however, microbes have short generation time and can rapidly evolve and potentially affect host physiology during stress. Here, we leverage Caenorhabditis elegans and its simplified bacterial diet to demonstrate how microbial adaptation to oxidative stress affects the host's lifespan and stress response. We find that worms fed stress-evolved bacteria exhibit enhanced stress resistance and an extended lifespan. Through comprehensive genetic and metabolic analysis, we find that iron in stress-evolved bacteria enhances worm stress resistance and lifespan via activation of the mitogen-activated protein kinase pathway. In conclusion, our study provides evidence that understanding microbial stress-mediated adaptations could be used to slow aging and alleviate age-related health decline.

Dynamically changed HSP70 after reperfusion following cerebral infarction in human and rats: correlation with p38 MAPK.

We aimed to clarify the correlation between dynamic change of blood HSP70 and the prognosis of thrombolysis in human and rats, so as to explain the neuroprotection and early warning role of HSP70 in cerebral ischemia-reperfusion. Forty-two patients with acute ischemic stroke were divided into two groups according to the time from onset to thrombolytic therapy: 0 h-3 h (27 patients) and 3-4.5 h group (15 patients). The level of HSP70 in serum before and after thrombolysis was detected by ELISA. Furthermore, a rat model was also used to mimic the ischemic stroke and reperfusion. Peripheral blood of rat samples was collected to detect the level of HSP70 using Elisa. Several signal proteins from MAPK signaling pathway including JNK, p38, ERK (p42/44) were detected at different time points by Western blot of brain tissue. Patients who underwent thrombolytic therapy within 0-3 h had the highest HSP70 level at 1 h after thrombolysis. The higher HSP70 after thrombolysis, the better the patient prognosis. NIHSS scores showed HSP70 was positively correlated with cerebral ischemia. The levels of ERK family (p42/44 MAPK) and p-JNK were decreased gradually along with the time suffering cerebral ischemia. P-ERK, JNK, p-p38 had dynamic changes with increased ischemic time in the middle cerebral artery occlusion model. Dynamic change of HSP70 level in blood may be a biological index that reflects the functional condition of cell survival for cerebral ischemia and estimating the prognostic conditions. Importantly, HSP70 levels in blood were positively correlated with the p38 MAPK pathway in brain tissue.

Homoharringtonine enhances cytarabine-induced apoptosis in acute myeloid leukaemia by regulating the p38 MAPK/H2AX/Mcl-1 axis.

Acute myeloid leukaemia (AML) is a fatal haematopoietic malignancy and is treated with the conventional combination of cytarabine (Ara-C) and daunorubicin (Dau). The survival rate of AML patients is lower due to the cardiotoxicity of daunorubicin. Clinically, homoharringtonine (HHT) plus Ara-C has been reported to be equally effective as Dau plus Ara-C in some types of AML patients with less toxic effects. We utilized the clinical use of homoharringtonine in combination with Ara-C to test its combination mechanism. We found that the insensitivity of AML cells to cytarabine-induced apoptosis is associated with increased Mcl-1 stability and p38 inactivation. HHT downregulates Mcl-1, phosphorylates H2AX and induces apoptosis by activating p38 MAPK. Inactivation of p38 through inhibitors and siRNA blocks apoptosis, H2AX phosphorylation and Mcl-1 reduction. HHT enhances Ara-C activation of the p38 MAPK signalling pathway, overcoming Ara-C tolerance to cell apoptosis by regulating the p38/H2AX/Mcl-1 axis. The optimal ratio of HHT to Ara-C for synergistic lethality in AML cells is 1:4 (M/M). HHT synergistically induces apoptosis in combination with Ara-C in vitro and prolongs the survival of xenografts. We provide a new mechanism for AML treatment by regulating the p38 MAPK/H2AX/Mcl-1 axis to improve cytarabine therapy.

The E3 Ubiquitin Protein Ligase LINCR Amplifies the TLR-Mediated Signals through Direct Degradation of MKP1.

Toll-like receptors (TLRs) induce innate immune responses through activation of intracellular signaling pathways, such as MAP kinase and NF-κB signaling pathways, and play an important role in host defense against bacterial or viral infections. Meanwhile, excessive activation of TLR signaling leads to a variety of inflammatory disorders, including autoimmune diseases. TLR signaling is therefore strictly controlled to balance optimal immune response and inflammation. However, its balancing mechanisms are not fully understood. In this study, we identified the E3 ubiquitin ligase LINCR/ NEURL3 as a critical regulator of TLR signaling. In LINCR-deficient cells, the sustained activation of JNK and p38 MAPKs induced by the agonists for TLR3, TLR4, and TLR5, was clearly attenuated. Consistent with these observations, TLR-induced production of a series of inflammatory cytokines was significantly attenuated, suggesting that LINCR positively regulates innate immune responses by promoting the activation of JNK and p38. Interestingly, our further mechanistic study identified MAPK phosphatase-1 (MKP1), a negative regulator of MAP kinases, as a ubiquitination target of LINCR. Thus, our results demonstrate that TLRs fine-tune the activation of MAP kinase pathways by balancing LINCR (the positive regulator) and MKP1 (the negative regulator), which may contribute to the induction of optimal immune responses.

Sprouty1 is a broad mediator of cellular senescence.

Genes of the Sprouty family (Spry1-4) restrain signaling by certain receptor tyrosine kinases. Consequently, these genes participate in several developmental processes and function as tumor suppressors in adult life. Despite these important roles, the biology of this family of genes still remains obscure. Here we show that Sprouty proteins are general mediators of cellular senescence. Induction of cellular senescence by several triggers in vitro correlates with upregulation of Sprouty protein levels. More importantly, overexpression of Sprouty genes is sufficient to cause premature cellular senescence, via a conserved N-terminal tyrosine (Tyrosine 53 of Sprouty1). Accordingly, fibroblasts from knockin animals lacking that tyrosine escape replicative senescence. In vivo, heterozygous knockin mice display delayed induction of cellular senescence during cutaneous wound healing and upon chemotherapy-induced cellular senescence. Unlike other functions of this family of genes, induction of cellular senescence appears to be independent of activation of the ERK1/2 pathway. Instead, we show that Sprouty proteins induce cellular senescence upstream of the p38 pathway in these in vitro and in vivo paradigms.