Toosendanin inhibits T-cell proliferation through the P38 MAPK signalling pathway

In recent years, immunosuppressants have shown significant success in the treatment of autoimmune diseases. Therefore, there is an urgent need to develop additional immunosuppressants that offer more options for patients. Toosendanin has been shown to have immunosuppressive activity in vitro as well as effects on autoimmune hepatitis (AIH) in vivo. Toosendanin did not induce apoptosis in activated T-cells and affect the survival rate of naive T-cells. Toosendanin did not affect the expression of CD25 or secretion of IL-2 by activated T-cells, and not affect the expression of IL-4 and INF-γ. Toosendanin did not affect the phosphorylation of STAT5, ERK, AKT, P70S6K. However, toosendanin inhibited proliferation of anti-CD3/anti-CD28 mAbs-activated T-cells with IC50 of (10 ± 2.02) nM. Toosendanin arrested the cell cycle in the G0/G1 phase, significantly inhibited IL-6 and IL-17A secretion, promoted IL-10 expression, and inhibited the P38 MAPK pathway. Finally, toosendanin significantly alleviated ConA-induced AIH in mice. In Summary, toosendanin exhibited immunosuppressive activity in vivo and in vitro. Toosendanin inhibits the proliferation of activated T-cells through the P38 MAPK signalling pathway, significantly suppresses the expression of inflammatory factors, enhances the expression of anti-inflammatory factors, and effectively alleviates ConA-induced AIH in mice, suggesting that toosendanin may be a lead compound for the development of novel immunomodulatory agents with improved efficacy and reduced toxicity.

Blocking H1R signal aggravates atherosclerosis by promoting inflammation and foam cell formation

Atherosclerosis (AS) is a chronic inflammatory arterial disease, in which abnormal lipid metabolism and foam cell formation play key roles. Histamine is a vital biogenic amine catalyzed by histidine decarboxylase (HDC) from L-histidine. Histamine H1 receptor (H1R) antagonist is a commonly encountered anti-allergic agent in the clinic. However, the role and mechanism of H1R in atherosclerosis have not been fully elucidated. Here, we explored the effect of H1R on atherosclerosis using Apolipoprotein E-knockout (ApoE-/-) mice with astemizole (AST, a long-acting H1R antagonist) treatment. The results showed that AST increased atherosclerotic plaque area and hepatic lipid accumulation in mice. The result of microarray study identified a significant change of endothelial lipase (LIPG) in CD11b+ myeloid cells derived from HDC-knockout (HDC-/-) mice compared to WT mice. Blocking H1R promoted the formation of foam cells from bone marrow-derived macrophages (BMDMs) of mice by up-regulating p38 mitogen-activated protein kinase (p38 MAPK) and LIPG signaling pathway. Taken together, these findings demonstrate that blocking H1R signal aggravates atherosclerosis by promoting abnormal lipid metabolism and macrophage-derived foam cell formation via p38 MAPK-LIPG signaling pathway. KEY MESSAGES: Blocking H1R signal with AST aggravated atherosclerosis and increased hepatic lipid accumulation in high-fat diet (HFD)-fed ApoE-/- mice. Blocking H1R signal promoted macrophage-derived foam cell formation via p38 MAPK-LIPG signaling pathway.

A critical role for Macrophage-derived Cysteinyl-Leukotrienes in HIV-1 induced neuronal injury

Macrophages (MΦ) infected with human immunodeficiency virus (HIV)-1 or activated by its envelope protein gp120 exert neurotoxicity. We found previously that signaling via p38 mitogen-activated protein kinase (p38 MAPK) is essential to the neurotoxicity of HIVgp120-stimulated MΦ. However, the associated downstream pathways remained elusive. Here we show that cysteinyl-leukotrienes (CysLT) released by HIV-infected or HIVgp120 stimulated MΦ downstream of p38 MAPK critically contribute to neurotoxicity. SiRNA-mediated or pharmacological inhibition of p38 MAPK deprives MΦ of CysLT synthase (LTC4S) and, pharmacological inhibition of the cysteinyl-leukotriene receptor 1 (CYSLTR1) protects cerebrocortical neurons against toxicity of both gp120-stimulated and HIV-infected MΦ. Components of the CysLT pathway are differentially regulated in brains of HIV-infected individuals and a transgenic mouse model of NeuroHIV (HIVgp120tg). Moreover, genetic ablation of LTC4S or CysLTR1 prevents neuronal damage and impairment of spatial memory in HIVgp120tg mice. Altogether, our findings suggest a novel critical role for cysteinyl-leukotrienes in HIV-associated brain injury.

Interferon-β deficiency alters brain response to chronic HIV-1 envelope protein exposure in a transgenic model of NeuroHIV

Human immunodeficiency virus-1 (HIV-1) infects the central nervous system (CNS) and causes HIV-associated neurocognitive disorders (HAND) in about half of the population living with the virus despite combination anti-retroviral therapy (cART). HIV-1 activates the innate immune system, including the production of type 1 interferons (IFNs) α and β. Transgenic mice expressing HIV-1 envelope glycoprotein gp120 (HIVgp120tg) in the CNS develop memory impairment and share key neuropathological features and differential CNS gene expression with HIV patients, including the induction of IFN-stimulated genes (ISG). Here we show that knocking out IFNβ (IFNβKO) in HIVgp120tg and non-tg control mice impairs recognition and spatial memory, but does not affect anxiety-like behavior, locomotion, or vision. The neuropathology of HIVgp120tg mice is only moderately affected by the KO of IFNβ but in a sex-dependent fashion. Notably, in cerebral cortex of IFNβKO animals presynaptic terminals are reduced in males while neuronal dendrites are reduced in females. The IFNβKO results in the hippocampal CA1 region of both male and female HIVgp120tg mice in an ameliorated loss of neuronal presynaptic terminals but no protection of neuronal dendrites. Only female IFNβ-deficient HIVgp120tg mice display diminished microglial activation in cortex and hippocampus and increased astrocytosis in hippocampus compared to their IFNβ-expressing counterparts. RNA expression for some immune genes and ISGs is also affected in a sex-dependent way. The IFNβKO abrogates or diminishes the induction of MX1, DDX58, IRF7 and IRF9 in HIVgp120tg brains of both sexes. Expression analysis of neurotransmission related genes reveals an influence of IFNβ on multiple components with more pronounced changes in IFNβKO females. In contrast, the effects of IFNβKO on MAPK activities are independent of sex with pronounced reduction of active ERK1/2 but also of active p38 in the HIVgp120tg brain. In summary, our findings show that the absence of IFNβ impairs memory dependent behavior and modulates neuropathology in HIVgp120tg brains, indicating that its absence may facilitate development of HAND. Moreover, our data suggests that endogenous IFNβ plays a vital role in maintaining neuronal homeostasis and memory function.

RAD23B mediated proteasomal degradation occurs through p38 MAPK/ATF-2/RAD23B axis under nutrient-deprived conditions in breast cancer

Metabolic reprogramming in cancer occurs due to interaction of cells with the surrounding tumor microenvironment. In the microenvironment of solid tumors, nutrient deprivation is induced by high consumption of nutrients and insufficient vasculature. Tumor cells alter their metabolic strategies to adapt to the microenvironment. To understand the role of these metabolic changes, in the current study, we have mimicked nutrient deprivation condition in vitro to evaluate the associated signaling pathways in breast cancer cells. In our study, we have shown that nutritional deprivation activated p38 MAPK and activating transcription factor-2 (ATF-2) by increased phosphorylation of Thr180/Tyr182 and Thr71, respectively, in breast cancer cells. Pharmacological inhibition of p38 MAPK showed increased cell viability and reduced expression of ATF-2 and RAD23B under nutrient starvation conditions. Further, silencing of ATF-2 showed increased cell viability and decreased expression of RAD23B under nutrient starvation conditions. This suggests the involvement of p38 MAPK/ATF-2/RAD23B axis as a signaling pathway under nutrition starvation in breast cancer cells. The RAD23B mediated proteasome activity was shown to be much higher under stress conditions indicating a crucial role of RAD23B as a target for breast cancer.

Lactate induces C2C12 myoblasts differentiation by mediating ROS/p38 MAPK signalling pathway

Lactate serves not merely as an energy substrate for skeletal muscle but also regulates myogenic differentiation, leading to an elevation of reactive oxygen species (ROS) levels. The present study was focused on exploring the effects of lactate and ROS/p38 MAPK in promoting C2C12 myoblasts differentiation. Our results demonstrated that lactate increased C2C12 myoblasts differentiation at a range of physiological concentrations, accompanied by enhanced ROS contents. We used n-acetylcysteine (NAC, a ROS scavenger) pretreatment and found that it delayed lactate-induced C2C12 myoblast differentiation by upregulating Myf5 expression on days 5 and 7 and lowering MyoD and MyoG expression. The finding implies that lactate accompanies ROS-dependent manner to promote C2C12 myoblast differentiation. Additionally, lactate significantly increased p38 MAPK phosphorylation to promote C2C12 cell differentiation, but pretreatment with SB203580 (p38 MAPK inhibitor) reduced lactate-induced C2C12 myoblasts differentiation. whereas lactate pretreatment with NAC inhibited p38 MAPK phosphorylation in C2C12 cells, demonstrating that lactate mediated ROS and regulated the p38 MAPK signalling pathway to promote C2C12 cell differentiation. In conclusion, our results suggest that the promotion of C2C12 myoblasts differentiation by lactate is dependent on ROS and the p38 MAPK signalling pathway. These observations reveal a beneficial role for lactate in increasing myogenesis through ROS-sensitive mechanisms as well as providing new ideas regarding the positive impact of ROS in improving the function of skeletal muscle.

Increased Expression of KNa1.2 Channel by MAPK Pathway Regulates Neuronal Activity Following Traumatic Brain Injury

Recent studies have indicated that functional abnormalities in the KNa1.2 channel are linked to epileptic encephalopathies. However, the role of KNa1.2 channel in traumatic brain injury (TBI) remains limited. We collected brain tissue from the TBI mice and patients with post-traumatic epilepsy (PTE) to determine changes in KNa1.2 channel following TBI. We also investigated whether the MAPK pathway, which was activated by the released cytokines after injury, regulated KNa1.2 channel in in vitro. Finally, to elucidate the physiological significance of KNa1.2 channel in neuronal excitability, we utilized the null mutant-Kcnt2-/- mice and compared their behavior patterns, seizure susceptibility, and neuronal firing properties to wild type (WT) mice. TBI was induced in both Kcnt2-/- and WT mice to investigate any differences between the two groups under pathological condition. Our findings revealed that the expression of KNa1.2 channel was notably increased only during the acute phase following TBI, while no significant elevation was observed during the late phase. Furthermore, we identified the released cytokines and activated MAPK pathway in the neurons after TBI and confirmed that KNa1.2 channel was enhanced by the MAPK pathway via stimulation of TNF-α. Subsequently, compared to WT mice, neurons from Kcnt2-/- mice showed increased neuronal excitability and Kcnt2-/- mice displayed motor deficits and enhanced seizure susceptibility, which suggested that KNa1.2 channel may be neuroprotective. Therefore, this study suggests that enhanced KNa1.2 channel, facilitated by the inflammatory response, may exert a protective role in an acute phase of the TBI model.

Function and inhibition of P38 MAP kinase signaling: Targeting multiple inflammation diseases

Inflammation is a natural host defense mechanism that protects the body from pathogenic microorganisms. A growing body of research suggests that inflammation is a key factor in triggering other diseases (lung injury, rheumatoid arthritis, etc.). However, there is no consensus on the complex mechanism of inflammatory response, which may include enzyme activation, mediator release, and tissue repair. In recent years, p38 MAPK, a member of the MAPKs family, has attracted much attention as a central target for the treatment of inflammatory diseases. However, many p38 MAPK inhibitors attempting to obtain marketing approval have failed at the clinical trial stage due to selectivity and/or toxicity issues. In this paper, we discuss the mechanism of p38 MAPK in regulating inflammatory response and its key role in major inflammatory diseases and summarize the synthetic or natural products targeting p38 MAPK to improve the inflammatory response in the last five years, which will provide ideas for the development of novel clinical anti-inflammatory drugs based on p38 MAPK inhibitors.

Alleviative Effect of Geniposide on Lipopolysaccharide-Stimulated Macrophages via Calcium Pathway

In this study, we investigated how geniposide (a bioactive ingredient of gardenia fruit) acts on lipopolysaccharide (LPS)-stimulated macrophages. Griess reagent assay, Fluo-4 calcium assay, dihydrorhodamine 123 assay, multiplex cytokine assay, quantitative RT-PCR, and flow cytometry assay were used for this study. Data showed that geniposide at concentrations of 10, 25, and 50 μM reduced significantly the levels of nitric oxide, intracellular Ca2+, and hydrogen peroxide in LPS-activated RAW 264.7. Multiplex cytokine assay showed that geniposide at concentrations of 10, 25, and 50 μM meaningfully suppressed levels of IL-6, G-CSF, MCP-1, and MIP-1α in RAW 264.7 provoked by LPS; additionally, geniposide at concentrations of 25 and 50 μM meaningfully suppressed the levels of TNF-α, IP-10, GM-CSF, and MIP-1β. Flow cytometry assay showed that geniposide reduces significantly the level of activated P38 MAPK in RAW 264.7 provoked by LPS. Geniposide meaningfully suppressed LPS-induced transcription of inflammatory target genes, such as Chop, Jak2, Fas, c-Jun, c-Fos, Stat3, Nos2, Ptgs2, Gadd34, Asc, Xbp1, Nlrp3, and Par-2. Taken together, geniposide exerts alleviative effects in LPS-stimulated macrophages via the calcium pathway.

Duck Tembusu virus infection activates the MKK3/6-p38 MAPK signaling pathway to promote virus replication

Duck Tembusu virus (DTMUV) infection poses a serious threat to ducks, chickens, and geese, causing a range of detrimental effects, including reduced egg production, growth retardation, and even death. These consequences lead to substantial economic losses for the Chinese poultry industry. Although it is established that various viral infections can trigger activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway, the precise role and mechanisms underlying p38 MAPK activation in DTMUV infection remain poorly understood. To address this knowledge gap, we conducted a study to investigate whether the replication of DTMUV necessitates the activation of p38 MAPK. We found that DTMUV infection stimulates activation of the MKK3/6-p38 MAPK pathway, and the activation of p38 MAPK increases with viral titer. Subsequently, the use of the small molecule inhibitor SB203580 significantly reduced DTMUV replication by inhibiting p38 MAPK activity. Furthermore, downregulation of p38 MAPK protein expression by siRNA also inhibited DTMUV replication, whereas transient transfection of p38 MAPK protein promoted DTMUV replication. Interestingly, we found that the DTMUV capsid protein activates p38 MAPK, and there is interaction between DTMUV capsid and p38 MAPK. Finally, we found that DTMUV infection induces elevated mRNA expression of IFN-α, IFN-β, IFN-γ, IL-1β, IL-6, and IL-12, which is associated with p38 MAPK activity. These results indicated that virus hijacking of p38 activation is a crucial event for DTMUV replication, and that pharmacological blockade of p38 activation represents a potential anti-DTMUV strategy.

Secretory products of DPSC mitigate inflammatory effects in microglial cells by targeting MAPK pathway

Activated microglial cells in the central nervous system (CNS) are the main contributors to neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Inhibiting their activation will help in reducing inflammation and oxidative stress during pathogenesis, potentially limiting the progression of the diseases. The immunomodulation properties of dental pulp-derived stem cells (DPSC) make it a promising therapy for neurodegenerative disorders. This study aims to determine whether secretory factors of DPSC (DPSC℗) inhibit inflammation and proliferation of microglial cells and define the molecular mechanisms. Our quantitative RT-PCR analysis showed that the DPSC℗ reduced the markers of the inflammation and induced anti-inflammatory molecules in microglial cells. DPSC ℗ reduced the intracellular and mitochondrial reactive oxygen species (ROS) production and mitochondrial membrane potential in microglial cells. In addition, DPSC ℗ decreased the cellular bioenergetics parameters related to oxygen consumption rate (OCAR) and extracellular acidification rate (ECAR). We found that DPSC℗ inhibited microglial cell proliferation by activating a checkpoint molecule, Chk1 leading an arrest at the G1 phase of the cell cycle. To define the mechanism, we performed the western blot analysis and observed that the MAPK P38 pathway was inhibited by DPSC℗. Furthermore, a System biology analysis revealed that the BDNF and GDNF, secretory factors of DPSC, blocked at the phosphorylation site (Tyr 182) of the P38 molecule resulting in the inhibition of downstream signaling of inflammation. These data suggest that the DPSC℗ may be a potential therapeutic agent for neurodegenerative diseases.

SILAC proteomics based on 3D cell spheroids unveils the role of RAC2 in regulating the crosstalk between triple-negative breast cancer cells and tumor-associated macrophages

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and is characterized by a high infiltration of tumor-associated macrophages (TAMs). TAMs contribute significantly to tumor progression by intricately interacting with tumor cells. Deeply investigating the interaction between TNBC cells and TAMs is of great importance for finding potential biomarkers and developing novel therapeutic strategies to further improve the clinical outcomes of TNBC patients. In this study, we confirmed the interplay using both 3D and 2D co-culture models. The stable-isotype labeling by amino acids in cell culture (SILAC)-based quantitative proteomics was conducted on 3D cell spheroids containing TNBC cells and macrophages to identify the potential candidate in regulating the crosstalk between TNBC and TAMs. Ras-related C3 botulinum toxin substrate 2 (RAC2) was identified as a potential molecule for further exploration, given its high expression in TNBC and positive correlation with M2 macrophage infiltration. The suppression of RAC2 inhibited TNBC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Meanwhile, knocking down RAC2 in TNBC cells impaired macrophage recruitment and M2 polarization. Mechanistically, RAC2 exerted its roles in TNBC cells and TAMs by regulating the activation of P65 NF-κB and P38 MAPK, while TAMs further elevated RAC2 expression and P65 NF-κB activation by secreting soluble mediators including IL-10. These findings highlight the significance of RAC2 as a crucial molecule in the crosstalk between TNBC and TAMs, suggesting it could be a promising therapeutic target in TNBC.

Apigenin protects melanocytes and improve tyrosinase activity in a hydroquinone induced vitiligo mouse model targeting P38 MAP kinase signaling: histopathology and immunohistochemistry analysis

Apigenin (APG) is a plant-based flavonoid that possesses antioxidants, anti-inflammatory, and modulates P38 MAPK as well as tyrosinase. Hydroquinone (HQ), a phenolic compound was used to induce vitiligo in C57BL/6 mice. The present study was performed to check the therapeutic potential of apigenin in HQ-induced vitiligo via targeting P38 MAPK pathway. In the present study, 41 C57BL/6 mice were divided into six groups containing seven animals per group except normal group. (I) normal group, (II) HQ group, (III) to (IV) APG with (1%, 2.5%, 5%), and (VI) tacrolimus (TAC) group. Topical application of HQ was performed from day 1 to day 20 to, (II), (III) to (IV) APG with (1%, 2.5%, 5%), (VI) tacrolimus (TAC) group, and then APG; tacrolimus (TAC) was applied from day 21 to day 60 after removing the hair. In the case of (I) normal group and (II) HQ group, we smeared them with water for 60 days and HQ for 20 days in their individual group. On day 61 after anesthesia, a part of the target skin was peeled and blood serum was taken to check the level of malondialdehyde, cholinesterase, catalase, tyrosinase, pro-inflammatory cytokines, and expression of P38 MAPK, histology of melanin containing hair follicles and depigmentation evaluation. Applying HQ topically had a noticeable impact on depigmentation, inflammatory indicators, oxidative stress, and lowered tyrosinase activity. Further HQ reduced melanin containing hair follicles and increased expression of P38 MAPK was confirmed by histopathology and immunohistochemistry. Furthermore, application of APG and TAC after day 21 to 60 significantly reduced depigmentation, inflammatory markers, oxidative stress, and increased tyrosinase. Furthermore, APG increased melanin containing hair follicles and decreased expression of non-phosphorylated P38 MAPK, as confirmed by histopathology and immunohistochemistry. Our finding demonstrated that APG significantly prevented HQ-induced vitiligo by acting as an anti-inflammatory, increasing tyrosine, and reducing the expression of non-phosphorylated P38 MAPK.

Cold stress causes liver damage by inducing ferroptosis through the p38 MAPK/Drp1 pathway

Acute extreme cold exposure impairs human health and even causes hypothermia which threatens human life. Liver, as a hub in metabolism and thermogenesis, is vital for cold acclimatization. Although accumulating evidence has suggested that cold exposure can cause liver damage, the underlying mechanisms remain poorly understood. This study investigated the role and underlying mechanisms of ferroptosis in cold stress-induced liver damage. To evaluate the role of ferroptosis in cold stress-induced liver damage, rats were pretreated with ferroptosis inhibitor liproxstatin-1 (Lip-1) before exposed to -10 °C for 8 h. Core body temperature was recorded. The levels of ferroptosis-related indicators were examined with the corresponding assay kits or by western blotting. Hepatic pathological changes were analyzed by hematoxylin-eosin staining and ultrastructural observation. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured to assess liver function. Rats were also pretreated with p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 or Dynamin-related protein 1 (Drp1) inhibitor Mdivi-1 to determine the underlying mechanisms. We found that Lip-1 inhibited ferroptosis, attenuated hepatic pathological damages and blocked the increased ALT and AST levels in cold-exposed rats. Moreover, Mdivi-1 inhibited mitochondrial fission and suppressed ferroptosis. Furthermore, SB203580 and Mdivi-1 administration alleviated cold stress-induced liver injury. Our results suggested that cold stress caused liver damage partially by inducing ferroptosis through the p38 MAPK/Drp1 pathway. These findings might provide an effective preventive and therapeutic target for cold stress-induced liver injury.

ZIP14 Affects the Proliferation, Apoptosis, and Migration of Cervical Cancer Cells by Regulating the P38 MAPK Pathway

BACKGROUND

Cervical cancer (CC) remains a major public health concern and is a leading cause of female mortality worldwide. Understanding the molecular basis of its pathogenesis is essential for the development of novel therapeutic strategies. In this study, we aimed to dissect the role of a specific molecule, ZIP14, in the initiation and progression of CC.

METHOD

We used Gene Expression Omnibus for target gene identification, while KEGG was used to delineate CC-related pathways. Proliferation, migration, and apoptosis levels in CC cells were assessed using CCK8, Transwell, and flow cytometry, respectively. The effect of the target genes on the in vivo tumorigenesis of CC cells was evaluated using the subcutaneous tumorigenesis assay.

RESULTS

ZIP14 (SLC39A14) was found to be underexpressed in CC samples. Our KEGG pathway analysis revealed the potential involvement of the P38 mitogen-activated protein kinase (MAPK) pathway in CC pathogenesis. Overexpression of ZIP14 in HeLa and Caski cells increased p38 phosphorylation, inhibited cell growth and migration, and enhanced apoptosis. Conversely, ZIP14 knockdown produced the opposite effects. Importantly, the bioeffects induced by ZIP14 overexpression could be counteracted by the p38 MAPK pathway inhibitor SB203580. In vivo experiments further confirmed the influence of ZIP14 on CC cell migration.

CONCLUSION

Our study is the first to elucidate the pivotal role of ZIP14 in the pathogenesis of CC, revealing its inhibitory effects through the activation of the p38 MAPK signaling pathway. The discovery not only provides a deeper understanding of CC's molecular underpinnings, but also highlights ZIP14 as a promising therapeutic target. As ZIP14 holds significant potential for therapeutic interventions, our findings lay a robust foundation for further studies and pave the way for the exploration of novel treatment modalities for cervical cancer.

IPO7 promotes lipopolysaccharide-induced inflammatory responses in human dental pulp cells via p38 MAPK and NF-κB signaling pathways

Pulpitis is a chronic inflammatory process that greatly affects the physical, mental health and life quality of patients. Human dental pulp cells (hDPCs) are essential components of dental pulp tissue and play a significant role in pulpitis. Lipopolysaccharide (LPS) is an initiator of pulpitis and can induce the production of inflammatory cytokines in hDPCs by activating p38 MAPK and NF-κB signaling pathways. Importin7 (IPO7), a member of the importin-β family, is widely expressed in many tissues. Previous studies have shown that IPO7 mediated nuclear translocation of p-p38 after stimulation, and IPO7 homologous protein IPO8 participated in human dental pulp inflammation. This research aims to investigate whether IPO7 is involved in pulpitis and explore its underlying mechanisms. In the current study, we found the expression of IPO7 was increased in pulpitis tissue. In vitro, hDPCs treated with LPS to mimic the inflammatory environment, the expression of IPO7 was increased. Knockdown of IPO7 significantly inhibited the production of inflammatory cytokines and suppressed the p38 MAPK and NF-κB signaling pathways. Activating the p38 MAPK and NF-κB signaling pathways by the p38 activator and p65 activator reversed the inflammatory responses. IPO7 interacted with p-p38 under LPS stimulation in hDPCs. In addition, the increased binding between IPO7 and p-p38 is associated with the decreased binding ability of IPO7 to Sirt2. In conclusion, we found that IPO7 was highly expressed in pulpitis and played a vital role in modulating human dental pulp inflammation.

Atorvastatin protects against cyclophosphamide-induced thyroid injury in rats via modulation of JNK/ ERK/ p38 MAPK signaling pathway

BACKGROUND

Cancer chemotherapy is associated with various tissue toxicities that limit its use. Cyclophosphamide (CYC) is one of the most commonly used antineoplastic and immunosuppressive agent. Thyroid dysfunction is a critical side effect of anticancer drugs. Atorvastatin (ATV) is antihyperlipedemic drug with different tissue protective activities. The aim of this study was to determine the potential protective effect of ATV against CYC-induced thyroid injury in rats.

METHODS

ATV was administered in the presence and absence of CYC. Thirty-two adult Wistar rats were randomly divided into four groups: control group, ATV group (20 mg/kg/day, p.o. for 14 day), CYC group (200 mg/kg, i.p. on day 9) and ATV/CYC group. Triiodothyronine (T3), thyroxine (T4), reduced glutathione (GSH), malondialdehyde (MDA), total nitrite/nitrate (NOx), p38 mitogen-activated protein kinase (P38MAPK), extracellular signal-regulated kinase (ERK) and c-Jun N-terminal Kinase (JNK) were measured. In addition, thyroid histopathology and caspase 3 immunohistochemistry were performed.

RESULTS

CYC significantly increased thyroid MDA, NOx, P38MAPK, ERK and JNK with decrease in GSH, T3 and T4 levels. Histopathological features of thyroid lesions and increased caspase 3 immune expression were appeared. ATV significantly normalized distributed oxidative, inflammatory and apoptotic indicators, resulting in an improvement of histopathological features and reduction of caspase 3 immunoexpression.

CONCLUSION

These findings suggest that ATV protects against CYC-induced thyroid injury by regulating the JNK/ERK/p38-MAPK signaling pathway.

Adiponectin inhibits TGF-β1-induced skin fibroblast proliferation and phenotype transformation via the p38 MAPK signaling pathway

The aim of this study was to investigate the effects of adiponectin (APN) on the proliferation and phenotypic transformation of human skin fibroblasts (HSFs) induced by TGF-β1. Primary fibroblast cultures were collected from prepuce surgery, and the cell viability and proliferative activity of HSFs were detected by Cell Counting Kit-8 and EdU assays. In addition, cell migration was detected by Transwell assay. The protein levels of related genes in HSF were detected by Western blotting. The results showed that the proliferation and migration abilities of HSF in the TGF-β1 group were significantly improved, and the relative protein expression levels of PCNA, α-SMA, and Collagen I in the TGF-β1 group were greatly increased. Furthermore, TGF-β1 stimulated the phosphorylation of p38 in HSF, while APN pretreatment significantly inhibited the TGF-β1-induced phosphorylation of p38. Additionally, blocking the p38 MAPK signaling pathway relieved the injury in the HSF induced by TGF-β1 and enhanced the therapeutic effect of APN in the TGF-β1-treated HSF. In conclusion, APN inhibits TGF-β1-induced HSF proliferation and myofibroblast phenotypic transformation by activating the p38 MAPK signaling pathway. APN is expected to become a potential target for preventing and treating skin fibrosis and pathological scars.

The role of ROS/p38 MAPK/NLRP3 inflammasome cascade in arsenic-induced depression-/anxiety-like behaviors of mice

Arsenic pollution in groundwater remains a serious public health concern around the world. Recent years, arsenic-related neurological and psychiatric disorders have been reported increasingly. However, the exact mechanisms of it remains elusive. In this study, arsenic exposure through drinking water resulted in depression-/anxiety-like behaviors in mice accompanied by oxidative stress and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome activation in prefrontal cortex (PFC) and hippocampus, two main affected areas found in neurobehavioral disorders. Intervention by NAC, a ROS scavenger, diminished the social behavior impairments in mice as well as ROS generation and NLRP3 inflammasome activation. Further study revealed that it was p38 MAPK signaling pathway that mediated ROS-induced NLRP3 inflammasome activation. Overall, our findings suggested that ROS/p38 MAPK/NLRP3 inflammasome cascade was involved in arsenic-induced depression-/anxiety-disorders. Furthermore, NAC might be a potential therapeutic agent for arsenic-induced depression-/anxiety-disorders by inhibiting both ROS generation and ROS-induced NLRP3 inflammasome activation.

Co-exposure to polystyrene microplastics and di-(2-ethylhexyl) phthalate aggravates allergic asthma through the TRPA1-p38 MAPK pathway

Increasing attention has been paid to the potential impact of microplastics (MPs) pollution on human health. MPs and phthalates coexist in the environment, however, the effects of exposure to MPs alone or to a combination of di-(2-ethylhexyl) phthalate (DEHP) and MPs on allergic asthma are unclear. This study investigates the effects of exposure to polystyrene microplastics (PS-MPs) or co-exposure with DEHP, on allergic asthma, and the underlying molecular mechanisms. We established an allergic asthma model using ovalbumin, and mice were exposed to PS-MPs (5 mg/kg bw/day) alone, or combined with DEHP (0.5, 5 mg/kg bw/day), for 28 days. The results showed that in the presence of ovalbumin (OVA) sensitization, exposure to PS-MPs alone slightly affected airway inflammation, and airway hyperresponsiveness, while co-exposure to PS-MPs and DEHP caused more significant damage. Co-exposure also induced more oxidative stress and Th2 immune responses, and activation of the TRPA1 and p38 MAPK pathways. The aggravation of asthmatic symptoms induced by co-exposure to PS-MPs and DEHP were inhibited by blocking TRPA1 ion channel or p38 MAPK pathway. The results demonstrated that co-exposure to PS-MPs and DEHP exacerbates allergic asthma, by exacerbating oxidative stress and inflammatory responses, and activating the TRPA1-p38 MAPK pathway.

Zinc depletion induces JNK/p38 phosphorylation and suppresses Akt/mTOR expression in acute promyelocytic NB4 cells

BACKGROUND

Myeloid leukemia is associated with reduced serum zinc and increased intracellular zinc. Our previous studies found that zinc depletion by TPEN induced apoptosis with PML-RARα oncoprotein degradation in acute promyelocytic NB4 cells. The effect of zinc homeostasis on intracellular signaling pathways in myeloid leukemia cells remains unclear.

OBJECTIVE

This study examined how zinc homeostasis affected MAPK and Akt/mTOR pathways in NB4 cells.

METHODS

We used western blotting to detect the activation of p38 MAPK, JNK, ERK1/2, and Akt/mTOR pathways in NB4 cells stimulated with the zinc chelator TPEN. Whether the effects of TPEN on these pathways could be reversed by zinc or the nitric oxide donor sodium nitroprusside (SNP) was further explored by western blotting. We used Zinpyr-1 staining to assess the role of SNP on labile zinc levels in NB4 cells treated with TPEN. In additional, we evaluated expressional correlations between the zinc-binding protein Metallothionein-2A (MT2A) and genes related to MAPKs and Akt/mTOR pathways in acute myeloid leukemia (AML) based on the TCGA database.

RESULTS

Zinc depletion by TPEN activated p38 and JNK phosphorylation in NB4 cells, whereas ERK1/2 phosphorylation was increased first and then decreased. The protein expression levels of Akt and mTOR were downregulated by TPEN. The nitric oxide donor SNP promotes zinc release in NB4 cells under zinc depletion conditions. We further found that the effects of zinc depletion on MAPK and Akt/mTOR pathways in NB4 cells can be reversed by exogenous zinc supplementation or treatment with the nitric oxide donor SNP. By bioinformatics analyses based on the TCGA database, we demonstrated that MT2A expression was negatively correlated with the expression of JNK, and was positively correlated with the expression of ERK1 and Akt in AML.

CONCLUSION

Our findings indicate that zinc plays a critical role in leukemia cells and help understanding how zinc depletion induces apoptosis.

The regulatory role and mechanism of lncTUG1 on cartilage apoptosis and inflammation in osteoarthritis

BACKGROUND

Long-stranded non-coding RNA TUG1 is lowly expressed in osteoarthritic chondrocytes. This study aimed to elucidate the role of TUG1 in osteoarthritic cartilage damage and the underlying mechanisms.

METHODS

Combined database analysis, using primary chondrocytes as well as the C28/I2 cell line, was performed by qRT-PCR, Western blotting, and immunofluorescence to determine the expression of TUG1, miR-144-3p, DUSP1, and other target proteins. Dual luciferase reporter gene and RIP to verify direct interaction of TUG1 with miR-144-3-p and miR-144-3-p with DUSP1, Annexin V-FITC/PI double staining to detect apoptosis. CCK-8 to detect cell proliferation. The biological significance of TUG1, miR-144-3p, and DUSP1 was assessed in vitro experiments using siRNA for TUG1, mimic and repressor for miR-144-3p, and overexpression plasmid for DUSP1. In this study, all data were subjected to a t-test or one-way analysis of variance with a p-value < 0.05 as the cutoff.

RESULTS

TUG1 expression was closely associated with osteoarthritic chondrocyte damage, and knockdown of TUG1 significantly promoted chondrocyte apoptosis and inflammation. In the present study, we found that TUG1 inhibited chondrocyte apoptosis and inflammation by competitively binding miR-144-3p, deregulating the negative regulatory effect of miR-144-3p on DUSP1, promoting DUSP1 expression, and inhibiting the p38 MAPK signaling pathway.

CONCLUSIONS

In conclusion, our study clarifies the role of the ceRNA regulatory network of TUG1/miR-144-3p/DUSP1/P38 MAPK in OA cartilage injury and provides an experimental and theoretical basis for genetic engineering tools to promote articular cartilage repair.

Andrographolide induced ferroptosis in multiple myeloma cells by regulating the P38/Nrf2/HO-1 pathway

Andrographis paniculata is used as a functional food in Asia. Andrographolide (Andro), a diterpene lactone isolated from Andrographis paniculata, has been reported to have potent anticancer activity. Multiple myeloma (MM), the second most common malignant tumor in hematology, is incurable. Ferroptosis, a type of cell death driven by iron-dependent lipid peroxidation, has shown potential in the treatment of various cancers. However, previous studies have not demonstrated whether Andro inhibits the development of MM via ferroptosis or any other mechanism. In the present study, we observed that Andro induced cell death, G0/G1 cell cycle arrest and evoked oxidative stress in MM cells. Interestingly, these phenomena were accompanied by increases in intracellular and mitochondrial Fe²⁺ and lipid peroxidation levels. Furthermore, treatment with ferroptosis inhibitors rescued Andro-induced cell death, which indicated that ferroptosis contributed to this phenomenon. Mechanistic examination showed that Andro may block the Nrf2/HO-1 signaling pathway by activating P38, thereby inducing ferroptosis. Moreover, inhibition of P38 expression rescued Andro-induced cell death, changes in the level of Nrf2 and HO-1 expression, Fe²⁺ and lipid peroxidation. Taken together, our findings suggest that Andro induces ferroptosis in MM cells via the P38/Nrf2/HO-1 pathway, providing a potential preventative and therapeutic approach for MM.

Selenium nanoparticles improve nickel-induced testosterone synthesis disturbance by down-regulating miR-708-5p/p38 MAPK pathway in Leydig cells

The present study was designed to investigate the role of miR-708-5p/p38 mitogen-activated protein kinase (MAPK) pathway during the mechanism of selenium nanoparticles (Nano-Se) against nickel (Ni)-induced testosterone synthesis disorder in rat Leydig cells. We conducted all procedures based on in vitro culture of rat primary Leydig cells. After treating Leydig cells with Nano-Se and NiSO₄ alone or in combination for 24 h, we determined the cell viability, reactive oxygen species (ROS) levels, testosterone production, and the protein expression of key enzymes involved in testosterone biosynthesis: steroidogenic acute regulatory (StAR) and cytochrome P450 cholesterol side chain cleavage enzyme (CYP11A1). The results indicated that Nano-Se antagonized cytotoxicity and eliminated ROS generation induced by NiSO₄ , suppressed p38 MAPK protein phosphorylation and reduced miR-708-5p expression. Importantly, we found that Nano-Se upregulated the expression of testosterone synthase and increased testosterone production in Leydig cells. Furthermore, we investigated the effects of p38 MAPK and miR-708-5p using their specific inhibitor during Nano-Se against Ni-induced testosterone synthesis disorder. The results showed that Ni-inhibited testosterone secretion was alleviated by Nano-Se co-treatment with p38 MAPK specific inhibitor SB203580 and miR-708-5p inhibitor, respectively. In conclusion, these findings suggested Nano-Se could inhibit miR-708-5p/p38 MAPK pathway, and up-regulate the key enzymes protein expression for testosterone synthesis, thereby antagonizing Ni-induced disorder of testosterone synthesis in Leydig cells.

Therapeutic effects of p38 mitogen-activated protein kinase inhibition on hyperexcitability of capsaicin sensitive bladder afferent neurons in mice with spinal cord injury

AIMS

Nerve growth factor (NGF) has been implicated as a key molecule of pathology-induced changes in C-fiber afferent nerve excitability, which contributes to the emergence of neurogenic detrusor overactivity due to spinal cord injury (SCI). It is also known that the second messenger signaling pathways activated by NGF utilize p38 Mitogen-Activated Protein Kinase (MAPK). We examined the roles of p38 MAPK on electrophysiological properties of capsaicin sensitive bladder afferent neurons with SCI mice.

MAIN METHODS

We used female C57BL/6 mice and transected their spinal cord at the Th8/9 level. Two weeks later, continuous administration of p38 MAPK inhibitor (0.51 μg/h, i.t. for two weeks) was started. Bladder afferent neurons were labelled with a fluorescent retrograde tracer, Fast-Blue (FB), injected into the bladder wall three weeks after SCI. Four weeks after SCI, freshly dissociated L6-S1 dorsal root ganglion neurons were prepared and whole cell patch clamp recordings were performed in FB-labelled neurons. After recording action potentials or voltage-gated K⁺ currents, the sensitivity of each neuron to capsaicin was evaluated.

KEY FINDINGS

In capsaicin-sensitive FB-labelled neurons, SCI significantly reduced the spike threshold and increased the number of action potentials during 800 ms membrane depolarization. Densities of slow-decaying A-type K⁺ (K_A) and sustained delayed rectifier-type K⁺ (K_DR) currents were significantly reduced by SCI. The reduction of K_A, but not K_DR, current density was reversed by the treatment with p38 MAPK inhibitor.

SIGNIFICANCE

P38 MAPK plays an important role in hyperexcitability of capsaicin-sensitive bladder afferent neurons due to the reduction in K_A channel activity in SCI mice.

Myricetin improves pathological changes in 3×Tg-AD mice by regulating the mitochondria-NLRP3 inflammasome-microglia channel by targeting P38 MAPK signaling pathway

BACKGROUND

Alzheimer's disease (AD) represents the common neurodegenerative disease featured by the manifestations of cognitive impairment and memory loss. AD could be alleviated with medication and improving quality of life. Clinical treatment of AD is mainly aimed at improving the cognitive function of patients. Donepezil, memantine and galantamine are commonly used drug. But they could only relieve AD, not cure it. Therefore, new treatment strategies focusing on AD pathogenesis are of great significance and value. Myricetin (Myr) is a natural flavonoid extracted from Myrica rubra. And it shows different bioactivities, such as anti-inflammation, antioxidation as well as central nervous system (CNS) activities. Nonetheless, its associated mechanism in treating AD remains unknown.

PURPOSE

Here we focused on investigating Myr's effect on treating AD and exploring if its protection on the nervous system activity was associated with specifically inhibiting P38 MAPK signaling pathway while regulating mitochondria-NLRP3 inflammasome-microglia.

STUDY DESIGN AND METHODS

This work utilized triple transgenic mice (3 × Tg-AD) as AD models and Aβ_25-35 was used to induce BV2 cells to build an in vitro AD model. Behavioristics, pathology and related inflammatory factors were examined. Molecular mechanisms are investigated by western-blot, immunofluorescence staining, CETSA, molecular docking, network pharmacology.

RESULTS

According to our findings, Myr could remarkably improve memory loss, spatial learning ability, Aβ plaque deposition, neuronal and synaptic damage in 3 × Tg-AD mice through specifically inhibiting P38 MAPK pathway activation while restraining microglial hyperactivation. Furthermore, Myr promoted the transformation of microglial phenotype, restored the mitochondrial fission-fusion balance, facilitated mitochondrial biogenesis, and restrained NLRP3 inflammasome activation and neuroinflammation. For the in-vitro experiments, P38 agonist dehydrocorydaline (DHC) was utilized to confirm the key regulatory role of P38 MAPK signaling pathway on the mitochondria-NLRP3 inflammasome-microglia channel.

CONCLUSIONS

Our results revealed the therapeutic efficacy of Myr in experimental AD, and implied that the associated mechanism is possibly associated with inhibiting tmitochondrial dysfunction, activating NLRP3 inflammasome, and neuroinflammation which was mediated by P38 MAPK pathway. Myr is the drug candidate in AD therapy via targeting P38 MAPK pathway.

Identification of MAP Kinase Kinase 3 as a protein target of myricetin in non-small cell lung cancer cells

Myricetin is a typical flavonol with various pharmacological effects which shows favorable biological activities in cancer. However, the underlying mechanisms and potential targets of myricetin in NSCLC (non-small cell lung cancer) cells remain unclear. First, we demonstrated that myricetin not only inhibited the proliferation, migration and invasion, but also induced apoptosis in A549 and H1299 cells in a dose-dependent manner. Then, we confirmed myricetin may play an anti-NSCLC effect through modulating MAPK-related functions and signaling pathway by Network pharmacology. Furthermore, MKK3 (MAP Kinase Kinase 3) was identified and confirmed as a potential target of myricetin by biolayer interferometry (BLI) and molecular docking, revealing that myricetin directly bound to MKK3. Moreover, three mutations (D208, L240, and Y245) of key amino acids predicted by molecular docking obviously decreased the affinity between myricetin and MKK3. Finally, enzyme activity assay was utilized to determine the effect of myricetin on MKK3 activity in vitro, and the result showed that myricetin attenuated MKK3 activity. Subsequently, myricetin decreased the phosphorylation of p38 MAPK. Furthermore, knockdown of MKK3 reduced the susceptibility of A549 and H1299 cells to myricetin. These results suggested that myricetin inhibited the growth of NSCLC cells via targeting MKK3 and influencing the downstream p38 MAPK signaling pathway. The findings revealed that MKK3 is a potential target of myricetin in the NSCLC and myricetin is considered to be a small-molecular inhibitor of MKK3, which can improve comprehension of the molecular mechanisms of myricetin pharmacological effects in cancer and further development of MKK3 inhibitors.

Thymol improves autism-like behaviour in VPA-induced ASD rats through the Pin1/p38 MAPK pathway

Inflammation plays an essential role in the pathogenesis of autism spectrum disorder (ASD). Thymol is a bioactive monoterpene isolated from Thymus vulgaris that has anti-inflammatory properties and is helpful in neurodevelopmental disorders. The purpose of this study was to investigate the effects of thymol on autism-like behaviours in rats with VPA-induced ASD and to assess the related molecular mechanisms. In the prefrontal cortex (PFC) of the valproic acid (VPA)-exposed rat model, the levels of Pin1, phosphorylated p38 MAPK, interleukin-1β (IL-1β) and tumour necrosis factor (TNF)-α, were increased, and the levels of PSD95 and synaptophysin (SYP) decreased. After thymol treatment (30 mg/kg), the VPA-induced autism-like behaviours were alleviated. Moreover, thymol also rescued the dysregulated levels of Pin1, phosphorylated p38 MAPK, IL-1β, TNF-α, PSD95, and SYP. In addition, immunofluorescence experiments showed that thymol treatment decreased the correlation between Pin1 and phosphorylated p38 MAPK. Mechanistically, Pin1 knockdown by RNA interference confirmed that Pin1 promotes inflammation via phosphorylation of p38 MAPK in the VPA exposure rat model. In conclusion, thymol improved autism-like behaviours in VPA-induced ASD rats by reducing inflammation and improving neurodevelopment. This effect was mediated by the Pin1/p38 MAPK pathway. These results experimentally provide the potential for thymol in new therapeutic avenues for autism.

Qiangguyin inhibited fat accumulation in OVX mice through the p38 MAPK signaling pathway to achieve anti-osteoporosis effects

Postmenopausal osteoporosis (PMOP) is a common bone disease characterized by decreased bone density and increased bone fragility due to decreased estrogen levels. Qiangguyin (QGY) is transformed from the famous traditional Chinese medicine BuShen Invigorating Blood Decoction. In this study, we used QGY to treat PMOP. We observed that QGY significantly reduced fat accumulation in the chondro-osseous junction. However, its specific mechanism of action remains unclear. To determine the specific molecular mechanism of QGY, we explored the pharmacological mechanism by which QGY reduces fat accumulation in the chondro-osseous junction through network pharmacological analysis. The active components and targets related to PMOP and QGY were screened from different databases, forming a composition-target-disease network. Next, a comprehensive analysis platform including protein-protein interaction (PPI) network, Gene Ontology (GO) enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were established. The results revealed that QGY inhibits adipogenic differentiation by activating the mitogen-activated protein kinase (MAPK) signaling pathway, thus reducing the accumulation of fat in the chondro-osseous junction. For further verification. In vitro and in vivo experiments were carried out. Our data showed that QGY significantly reversed the high expression of fatty acid binding protein 4 (FABP4) and peroxisome proliferator-activated receptor γ (PPARγ). Further, QGY prevents fat accumulation by inhibiting the expression of p38. In summary, the results of this study suggested that QGY-induced phenotypic changes are related to the activation of the p38 MAPK signaling pathway.

PAR2 Overexpression is Involved in the Occurrence of Hyperoxygen-Induced Bronchopulmonary Dysplasia in Rats

BACKGROUND

Bronchopulmonary dysplasia is a chronic lung disease commonly seen in preterm infants. It is characterized by delayed development of the alveoli and lung fibrosis. Protease-activated receptor 2 (PAR2) is an inflammatory driver that plays a proinflammatory role mainly through the P38 MAPK/NF-κB signaling pathway.

METHODS

Newborn rat pups were kept under air or oxygen at >60% concentration. Lung tissues were collected at postnatal days (P) 1, 4, 7, and 10 to observe pathological changes and take measurements.

RESULTS

In the hyperoxic group, P4 and P7 rats showed delayed alveolar development, septal thickening, and disturbances in alveolar structure.PAR2, P38 MAPK, NF-κB, and IL-18 expression at P4, P7, and P10 was significantly higher than in the air group.

CONCLUSION

PAR2 is involved in lung injury induced by persistent hyperoxia. Activated PAR2 promotes IL-18 overexpression through the P38 MAPK/NF-κB signaling pathway, which may be an important mechanism of PAR2-mediated lung injury in bronchopulmonary dysplasia.

Metastatic effects of environmental carcinogens mediated by MAPK and UPR pathways with an in vivo Drosophila Model

Metastasis includes tumor invasion and migration and underlies over 90% of cancer mortality. The metastatic effects of environmental carcinogens raised serious health concerns. However, the underlying mechanisms remained poorly studied. In the present study, an in vivo Ras^V12/lgl^-/- model of the fruitfly, Drosophila melanogaster, with an 8-day exposure was employed to explore the metastatic effects of 3,3',4,4',5-pentachlorobiphenyl (PCB126), perfluorooctanoic acid (PFOA) and cadmium chloride (CdCl₂). At 1.0 mg/L, PCB126, PFOA, and CdCl₂ significantly increased tumor invasion rates by 1.32-, 1.33-, and 1.29-fold of the control, respectively. They also decreased the larval body weight and locomotion behavior. Moreover, they commonly disturbed the expression levels of target genes in MAPK and UPR pathways, and their metastatic effects were significantly abolished by the addition of p38 inhibitor (SB203580), JNK inhibitor (SP600125) and IRE1 inhibitor (KIRA6). Notably, the addition of the IRE inhibitor significantly influenced sna/E-cad pathway which is essential in both p38 and JNK regulations. The results demonstrated an essential role of sna/E-cad in connecting the effects of carcinogens on UPR and MAPK regulations and the resultant metastasis.

Cigarette smoke extract combined with LPS reduces ABCA3 expression in chronic pulmonary inflammation may be related to PPARγ/ P38 MAPK signaling pathway

ABCA3 (ATP-binding cassette class A3) is a transmembrane transporter that plays a positive role in chronic pulmonary inflammation by regulating lipid metabolism. However, it is not completely clear whether ABCA3 and its signaling factors are involved in chronic pulmonary inflammation induced by the combination of CSE (cigarette smoke extract) and LPS (lipopolysaccharide). In this study, we used the method of combining CSE and LPS which was widely used to study lung inflammation-related diseases and has been proven effective in our group's studies to create in vivo and in vitro pulmonary inflammation models. The result showed that, after CSE in combination with LPS treatment, ABCA3 expression was downregulated in rat lung in vivo and in a human alveolar cell line in vitro. ABCA3 expression was upregulated, and related inflammatory factors were downregulated in the state of overexpression of PPARγ or inhibition of the p38 MAPK pathway, while PPARγ deletion or MAPK14 overexpression showed the opposite results. The level of PPARγ remained unchanged, and the expression of ABCA3 was upregulated in the state of the p38 MAPK pathway was inhibited under overexpression of PPARγ. These results indicate that CSE combined with LPS can result in downregulation of ABCA3 under conditions of inflammation, and that the p38 MAPK signaling pathway mediated by PPARγ can regulate the expression changes of ABCA3, thus providing new targets for treating chronic pulmonary inflammation.

Inhibition of P2Y6 receptor expression in Kupffer cells alleviates alcoholic steatohepatitis in mice

Inflammation plays an important role in the progression of alcohol-related liver disease (ALD). UDP-P2Y₆ signaling is involved in many human diseases. The purinergic P2Y₆ receptor, an important regulator of inflammation and phagocytosis, has attracted attention, but its role in alcoholic steatohepatitis remains unclear. Here, we found that P2Y₆ levels were significantly elevated in Kupffer cells in the livers of mice with alcoholic steatohepatitis and ethanol (EtOH)-induced RAW264.7 cells. In this study, mice with alcoholic steatohepatitis were intraperitoneally injected with MRS2578, a specific inhibitor of the P2Y₆ receptor, and P2Y₆ was silenced in EtOH-induced RAW264.7 cells. We found a marked improvement in steatosis and inflammation in the livers of mice with alcoholic steatohepatitis and EtOH-induced RAW264.7 cells. However, P2Y₆ activation in vivo and overexpression in vitro showed contrasting results. In addition, the expression of phospho-p38 mitogen-activated protein kinase (p-p38 MAPK), a phosphorylated protein in the p38 MAPK signaling pathway, was significantly altered after P2Y₆ silencing or overexpression in vitro. P2Y₆ can induce the activation of the p38 MAPK signaling pathway by mediating the calcium influx, whereas inhibition of the expression of P2Y₆ can block the inflammatory process to some extent and thus improve the inflammatory response. The results of this study suggested that targeting P2Y₆ signaling may be a potentially effective strategy for the treatment of alcoholic steatohepatitis.

HDAC9 in the Injury of Vascular Endothelial Cell Mediated by P38 MAPK Pathway

Ischemic stroke caused by atherosclerosis (AS) poses a serious threat to human life expectancy and quality. With the development of genome-wide association studies, the association of histone deacetylase 9 (HDAC9) expression of atheromatous plaques with ischemic stroke in large arteries has been revealed, but the molecular mechanisms behind this phenomenon have not been elucidated. In this study, we explored the effect of HDAC9 on the P38 mitogen activated protein kinase (P38 MAPK), a classic cellular inflammation-related pathway, by knocking down HDAC9 in vascular endothelial cells with short hairpin RNA (shRNA) and found that HDAC9 may mediate oxidized low density lipoprotein (ox-LDL)-induced inflammatory injury in vascular endothelial cells by regulating the phosphorylation level of P38 MAPK to lead to AS. It can be seen that HDAC9 may be a target to control the formation of atherosclerotic plaques. In follow-up experiments, it was verified that sodium valproate (SVA), as a HDAC9 inhibitor, can indeed antagonize the inflammatory damage of vascular endothelial cells, as well as SB203580, which is a P38 MAPK inhibitor. It proves that SVA may be a potential drug for the prevention and treatment of ischemic stroke.

P38 MAPK/AKT signalling is involved in IL-33-mediated anti-apoptosis in childhood acute lymphoblastic leukaemia blast cells

BACKGROUND

Acute lymphoblastic leukaemia (ALL) is often characterized by broad clinical and biological heterogeneity, as well as recurrent genetic aberrations. Despite remarkable improvements in the treatment outcome in paediatric ALL over the past several decades, it remains a leading cause of morbidity and mortality among children. Cytokines have been extensively studied in haematologic diseases; however, the mechanisms by which cytokines contribute to ALL pathogenesis remain poorly understood.

METHODS

IL-33 levels were measured by enzyme-linked immunosorbent assay (ELISA). IL1RL1 expression on ALL cell surface was accessed by flow cytometry. Expression of phosphorylated p38 MAPK, p38, pAKT, AKT and GAPDH were quantified by western blot. Cell survival signals were evaluated by apoptosis using flow cytometry.

RESULTS

BM samples from ALL patients at diagnosis upregulated their cell surface expression of IL1RL1, and a higher interleukin (IL)-33 level in the serum was observed as compared to the healthy individuals. Moreover, exogenous IL-33 treatment significantly inhibited apoptosis by activating p38 mitogen-activated protein kinase (MAPK) and AKT pathway, while the inhibitor for p38 MAPK, SB203580, counteracted IL-33-induced anti-apoptosis via inactivation of p38 MAPK and AKT. Furthermore, IL-33 negatively regulates cyclin B1 protein level while increasing the expression of CDK1, with SB203580 inhibiting the effect.

CONCLUSION

Our study reveals an important role for IL-33/IL1RL1 axis in supporting ALL which may represent a novel treatment for paediatric patients.KEY MESSAGESBoth IL-33 and IL1RL1 levels are upregulated in primary ALL samples.IL-33 increased both p38 MAPK and AKT activation in ALL.IL-33 promotes survival and cell cycle progression of ALL cells via activating p38 MAPK.

The circadian clock regulator Bmal1 affects traumatic brain injury in rats through the p38 MAPK signalling pathway

Traumatic brain injury (TBI) is still one of the main causes of death and disability worldwide. Bmal1 (brain and muscle Arnt-like protein-1) is the most central factor of the circadian rhythms that control life and cells. Studies have shown that Bmal1 is involved in inflammation, oxidative stress, vasodilation, glucose and lipid metabolism. This study explored the effect of Bmal1 on secondary brain injury after TBI in rats and the possible mechanism. We established a rat model of TBI induced by the free fall of a weight in rats. The Western blotting and immunofluorescence results showed that the Bmal1 levels decreased in the cerebral cortex after TBI, especially at 48 h. The effects of Bmal1 levels on rats after TBI were evaluated by brain oedema measurement, adhesive removal tests, behavioural tests, and TUNEL and FJC staining. We found that the recombinant Bmal1 protein increased Bmal1 levels after TBI and reduced brain oedema, neurobehavioural injury, somatosensory disturbances, and nerve cell necrosis and apoptosis. The ELISA results showed that Bmal1 overexpression could reduce the inflammatory factors IL-4 and TNF-α after TBI. In contrast, inhibiting Bmal1 expression had the opposite effect. The changes in Bmal1 levels were closely related to the phosphorylation of p38 MAPK after TBI. In conclusion, a decrease in Bmal1 after TBI may exacerbate pathological symptoms in vivo by activating p38 MAPK phosphorylation.

Downregulation of GNA15 Inhibits Cell Proliferation via P38 MAPK Pathway and Correlates with Prognosis of Adult Acute Myeloid Leukemia With Normal Karyotype

Background

The prognosis of acute myeloid leukemia (AML) with a normal karyotype is highly heterogonous, and the current risk stratification is still insufficient to differentiate patients from high-risk to standard-risk. Changes in some genetic profiles may contribute to the poor prognosis of AML. Although the prognostic value of G protein subunit alpha 15 (GNA15) in AML has been reported based on the GEO (Gene Expression Omnibus) database, the prognostic significance of GNA15 has not been verified in clinical samples. The biological functions of GNA15 in AML development remain open to investigation. This study explored the clinical significance, biological effects and molecular mechanism of GNA15 in AML.

Methods

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression level of GNA15 in blasts of bone marrow specimens from 154 newly diagnosed adult AML patients and 26 healthy volunteers. AML cell lines, Kasumi-1 and SKNO-1, were used for lentiviral transfection. Cell Counting Kit-8 (CCK8) and colony formation assays were used to determine cell proliferation. Cell cycle and apoptosis were analyzed by flow cytometry. The relevant signaling pathways were evaluated by Western blot. The Log-Rank test and Kaplan-Meier were used to evaluate survival rate, and the Cox regression model was used to analyze multivariate analysis. Xenograft tumor mouse model was used for in vivo experiments.

Results

The expression of GNA15 in adult AML was significantly higher than that in healthy individuals. Subjects with high GNA15 expression showed lower overall survival and relapse-free survival in adult AML with normal karyotype. High GNA15 expression was independently correlated with a worse prognosis in multivariate analysis. Knockdown of GNA15 inhibited cell proliferation and cell cycle progression, and induced cell apoptosis in AML cells. GNA15-knockdown induced down-regulation of p-P38 MAPK and its downstream p-MAPKAPK2 and p-CREB. Rescue assays confirmed that P38 MAPK signaling pathway was involved in the inhibition of proliferation mediated by GNA15 knockdown.

Conclusions

In summary, GNA15 was highly expressed in adult AML, and high GNA15 expression was independently correlated with a worse prognosis in adult AML with normal karyotype. Knockdown of GNA15 inhibited the proliferation of AML regulated by the P38 MAPK signaling pathway. Therefore, GNA15 may serve as a potential prognostic marker and a therapeutic target for AML in the future.

Effect of L-thyroxine administration on long-term potentiation and accompanying mitogen-activated protein kinases in rats

The present study investigated the differences in the activation of c-Jun NH2-terminal kinases (JNK), p38 mitogen-activated protein kinases (p38^MAPK ), and extracellular signal-regulated kinases 1/2 (Erk1/2) 1 hr after the induction of long-term potentiation (LTP) between rats with hyperthyroidism that was produced at two different stages of development. Hyperthyroidism was produced in rats by daily injections of L-thyroxine (T4, ip., 0.2 mg/kg) to their dams for lactation period or to the rats itself during the young adult period. LTP was induced by application of high-frequency stimulation protocol. Five-min averages of the excitatory postsynaptic potential (EPSP) slopes and population spike (PS) amplitudes at the end of recording were averaged to measure the magnitude of LTP. Total and phosphorylated levels of Erk1/2, JNK, and P38-MAPK were assessed via western blotting in these hippocampi. LTP was found to be impaired in both groups of hyperthyroidisms, but this impairment observed together with increased expression and phosphorylation of ERK1/2, and increased phosphorylation of JNK in rats treated maternally with T4 compared to those treated adultly. These results suggest that excessiveness of thyroid hormone has longstanding effects on hippocampal function and may account for failed LTP in both early and relatively late stage of development depending on various molecular pathways, such as ERK1/2 and JNK.

Mechanical Stretch Induces Smooth Muscle Cell Dysfunction by Regulating ACE2 via P38/ATF3 and Post-transcriptional Regulation by miR-421

Mechanical stretch promotes deregulation of vascular smooth muscle cell (VSMC) functions during hypertension-induced vascular remodeling. ACE2 has a wide range of cardiovascular and renal protective effects. Loss of ACE2 is associated with cardiovascular disease, but little is known about the regulation of its expression, especially by abnormal mechanical stretch during hypertension. The present study was designed to investigate the contribution of ACE2 to vascular remodeling under mechanical stretch and to assess the possible underlying mechanisms. The abdominal aortic constriction model was established to mimic the environment in vivo. FX-5000T Strain Unit provided mechanical stretch in vitro. Overexpression was used to analyze the role of ACE2 played in the proliferation, migration, apoptosis, and collagen metabolism of the VSMCs. RT-qPCR, Western blot, luciferase assay, and ChIP assay were used to elucidate the molecular mechanism of ACE2 expression regulated by stretch. We found that mechanical stretch modulated the expression of the ACE2/Ang-(1–7) and ACE/AngII axis. ACE2 was mechanically sensitive and was involved in the stretch-induced dysfunction of VSMCs. The p38 MAPK/ATF3 pathway and miR-421 participated in the regulation of ACE2. Thus, ACE2 may contribute to the development of vascular remodeling under conditions of mechanical stretch.

The EGFR-P38 MAPK axis up-regulates PD-L1 through miR-675-5p and down-regulates HLA-ABC via hexokinase-2 in hepatocellular carcinoma cells

BACKGROUND

Immunotherapy has been shown to be a promising strategy against human cancers. A better understanding of the immune regulation in hepatocellular carcinoma (HCC) could help the development of immunotherapy against HCC. The epidermal growth factor receptor (EGFR) signaling is frequently activated in HCC and plays important roles in tumorigenesis. However, its role in HCC immunity is still largely unknown. This study aimed to investigate the impact of EGFR signaling on programmed death-ligand 1 (PD-L1) and human leukocyte antigen class-I (HLA-I) expression in HCC cells and its underlying mechanisms.

METHODS

The expression of phosphorylated EGFR (p-EGFR), PD-L1, and HLA-I (HLA-ABC) in HCC specimens was detected by immunohistochemistry, and their correlations were analyzed. PD-L1 and HLA-ABC expression in EGFR-activated HCC cells were detected by quantitative real-time PCR, Western blotting, and flow cytometry, and T cell-mediated lysis was performed to test the immunosuppressive effects of PD-L1 and HLA-ABC alterations in HCC cells. Furthermore, the underlying mechanisms of EGFR activation-induced PD-L1 up-regulation and HLA-ABC down-regulation were explored by animal experiments, luciferase reporter assay, and gene gain- and loss-of-function studies.

RESULTS

p-EGFR was positively correlated with PD-L1 and negatively correlated with HLA-ABC expression in HCCs. EGFR activation by its ligand EGF up-regulated PD-L1 and down-regulated HLA-ABC in HCC cells, which was functionally important and could be abolished by the EGFR inhibitor, gefitinib, both in vitro and in vivo. Mechanistically, enhanced P38 mitogen-activated protein kinase (MAPK) activation down-regulated microRNA-675-5p (miR-675-5p) and up-regulated glycolysis-related enzyme hexokinase 2 (HK2); miR-675-5p down-regulation enhanced the stability of PD-L1 mRNA probably via the 3'-untranslated region (3'-UTR) of PD-L1 and thereby caused PD-L1 accumulation, and HK2 up-regulation enhanced aerobic glycolysis and mediated a decrease in HLA-ABC.

CONCLUSIONS

The EGFR-P38 MAPK axis could up-regulate PD-L1 through miR-675-5p and down-regulate HLA-ABC via HK2 in HCC cells. Our study reveals a novel signaling network that may cause immune suppression in HCC and suggests that EGFR signaling can be targeted for HCC immunotherapy.

Zinc homeostasis plays an important role in the prevention of obesity-induced cardiac inflammation, remodeling and dysfunction

Obesity often leads to cardiovascular diseases, such as obesity-related cardiac hypertrophy (ORCH), due to chronic cardiac inflammation. Zinc is structurally and functionally essential for many transcription factors, therefore it not only has anti-inflammatory and anti-oxidative stress functions, but also has insulin-like function, however, its role in the development of obesity-associated cardiac pathogenesis and the potentially underlying mechanism(s) remains unclear. This review aims to summarize the available evidence on the role of zinc homeostasis in the prevention of ORCH. It was recently reported that when four-week old mice were fed either high fat diet (HFD) or normal diet containing deficient, adequate or supplemented zinc, HFD induced obesity and ORCH along with increased phosphorylation of p38 MAPK and increased expression of B-cell lymphoma/ leukemia 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These effects were further aggravated by zinc deficiency and significantly alleviated by zinc supplementation. Mechanistically administration of a p38 MAPK specific inhibitor in HFD-fed mice for 3 months did not affect HFD-induced obesity and increased expression of BCL10 and CARD9, but completely abolished HFD/obesity-induced cardiac hypertrophy and inflammation. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. Taken together with other recent studies, we concluded that HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signaling. Zinc supplementation ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation.

Mechanisms Involved in Superiority of Angiotensin Receptor Blockade over ACE Inhibition in Attenuating Neuropathic Pain Induced in Rats

Although previous reports described the beneficial role of angiotensin-converting enzyme inhibitors (ACE-Is) or AT1 receptor blockers (ARBs) in attenuating neuropathic pain (NP), no study has yet explored the exact underlying mechanisms, as well as the superiority of using centrally versus peripherally acting renin-angiotensin-aldosterone system (RAAS) drugs in NP. We investigated the effects of 14 days of treatment with centrally (telmisartan and ramipril) or peripherally (losartan and enalapril) acting ARBs and ACE-Is, respectively, in attenuating peripheral NP induced by sciatic nerve chronic constriction injury (CCI) in rats. We also compared these with the effects of pregabalin, the standard treatment for NP. Behavioral changes, inflammatory markers (NFкB, TNF-α, COX-2, PGE2, and bradykinin), oxidative stress markers (NADPH oxidase and catalase), STAT3 activation, levels of phosphorylated P38-MAPK, ACE, AT1 receptor (AT1R), and AT2 receptor (AT2R), as well as histopathological features, were assessed in the brainstem and sciatic nerve. CCI resulted in clear pain-related behavior along with increased levels of inflammatory and oxidative stress markers, and STAT3 activity, as well as increased levels of phosphorylated P38-MAPK, ACE, AT1R, and AT2R, along with worsened histopathological findings in both the brainstem and sciatic nerve. ARBs improved both animal behavior and all measured parameters in CCI rats and were more effective than ACE-Is. At the tested doses, centrally acting ARBs or ACE-Is were not superior to the peripherally acting drugs of the same category. These findings suggest that ARBs (centrally or peripherally acting) are an effective treatment modality for NP.

Sinensetin suppresses influenza a virus-triggered inflammation through inhibition of NF-κB and MAPKs signalings

Background

Human respiratory system infected with influenza A virus (IAV) elicited a robust pro-inflammatory response that resulted in severe illness and even death. Currently, limited immunomodulator is available to counteract IAV-associated pneumonia in the clinic. Sinensetin, a polymethoxylated flavone with five methoxy groups, has been found to possess anti-agiogenesis, anti-inflammatory and anti-diabetic activities. However, the effects of sinensetin on IAV-triggered pro-inflammatory response remain unclear. In the present study, the anti-inflammatory effects and corresponding possible mechanism of sinensetin in IAV-infected A549 cells were subjected to investigations.

Methods

The cytotoxic effects of sinensetin towards A549 cells was detected by MTT and LDH assays. The antiviral activity of sinensetin against influenza A virus was assayed in A549 cells with an engineered replication-competent influenza A virus carrying Gaussia luciferase reporter gene infection. The effect of sinensetin on influenza A virus-triggered inflammatory reaction was determined by qRT-PCR, Luminex assays, ELISA and Western blot.

Results

Our results showed that sinensetin did not exhibit antiviral activity against A/PR/8/34 (H1N1). Meanwhile, sinensetin treatment significantly decreased IAV-induced expression of pro-inflammatory mediators at mRNA and protein levels, including IL-6, TNF-α, IP-10, IL-8 and MCP-1. Additionally, levels of cyclooxygenase (COX)-2 and the downstream product prostaglandin E₂ (PGE₂) up-regulated by IAV infection were dramatically suppressed by sinensetin. The mechanistic investigation revealed that sinensetin treatment suppressed the NF-κB transcriptional activity using the NF-κB reporter stable HEK293 cell line stimulated with TNF-α (20 ng/mL) or influenza H1N1 virus. Furthermore, sinensetin abrogated influenza H1N1 virus-induced activation of NF-κB, ERK1/2 MAPK and p38 MAPK signalings.

Conclusion

Collectively, our results indicated that sinensetin has potential capacity to attenuate IAV-triggered pro-inflammatory response via inactivation of NF-κB, ERK1/2 MAPK and p38 MAPK signalings, which implied that sinensetin may be a promising candidate drug for influenza H1N1 virus infection therapeutics.

Ethanol Stimulation of Microglia Release Increases ERK1/2-Dependent Neuronal cPLA2 Activity in Immature Cultured Cortical Preparations

Ethanol consumption typically begins during adolescence and is associated with age-dependent responses and maladaptive neuronal consequences. Our previous work established the role of a putative signaling cascade involving cytoplasmic phospholipase A₂ (cPLA₂), arachidonic acid (AA) and novel protein kinase C isoforms in adolescent hypnotic sensitivity. The current study aimed to further delineate this pathway by ascertaining the cellular specificity as well as the upstream activators of cPLA₂ using an immature cultured cortical preparation. A threefold increase in cPLA₂ was detected within 2 min of 100 mM ethanol exposure as measured by phosphorylation of serine 505 (Ser505). Increases in cPLA₂ activity were further observed to be primarily confined to neuronal cells. Increases in the number of neurons co-expressing cPLA2 Ser505 phosphorylation were prevented by preincubation with an ERK1/2 inhibitor, but not P38 MAPK inhibition. Finally, conditioned media studies were used to determine whether glial cells were involved in the ethanol-induced neuronal cPLA₂ activity. Rapid increases in neuronal cPLA2 activity appears to be initiated through ethanol stimulated microglial, but not astrocytic releasable factors. Taken together, these data extend the proposed signaling cascade involved in developmental ethanol responding.

Ferrostatin-1 mitigates cognitive impairment of epileptic rats by inhibiting P38 MAPK activation

Evidence indicates that ferrostain-1 (Fer-1), a specific inhibitor of ferroptosis, could ameliorate cognitive dysfunction of rats with kainic acid (KA)-induced temporal lobe epilepsy (TLE) by suppressing ferroptosis processes. Recent studies suggest that P38 mitogen-activated protein kinase (MAPK) pathway could be mediated by ferroptosis processes. The activation of P38 MAPK results in cognitive impairment by suppressing the expression of synaptic plasticity-related proteins. However, it is unclear whether Fer-1 can mitigate cognitive impairment of rats with KA-induced TLE by inhibiting P38 MAPK activation. In the present study, treatment with Fer-1 blocked the activation of P38 MAPK, which resulted in an increased expression of synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95) in the hippocampus of rats with KA-induced TLE, hence, ameliorating their cognitive impairment. Also, P38 MAPK activation in the hippocampus of the rats reduced the expression of both PSD-95 and SYP proteins. Treatment of the rats with SB203580, a P38 MAPK-specific inhibitor, prevented the activation of P38 MAPK, which resulted in an increase in SYP and PSD95 protein levels in the hippocampus. These results suggest that Fer-1 could mitigate the cognitive impairment by suppressing P38 MAPK activation thus restoring the expression of synaptic proteins. Ferroptosis processes might be involved in suppressing synaptic protein expression.

Design and Synthesis of Novel 1-hydroxy-2,4,5-triaryl Imidazole Derivatives as Anti-cytokine Agents

Among recent advances in the identification of anti-inflammation agents, anti-cytokines (like Interleukin-1), related to p38 MAPK families play an important role; Here in we designed new effective and low toxic anti-cytokine agents based on 1-hydroxy-2,4,5-triaryl imidazole derivatives. The reaction of oximoinoketone intermediate with ten different aromatic aldehyde and ammonium acetate in refluxing acetic acid condition give imidazole derived product, the IL-1β inhibitory assay were performed on Human PBMCs (peripheral blood mononuclear cells) using an enzyme-linked immunosorbent assay (ELISA) kit and then in computational part the binding mode of the best compound was accomplished by docking in Crystal structure of p38 MAP kinase (PDB ID: 1A9U) compared with SB202190 as standard drug. All compounds were synthesized and evaluated in biological assay showing the inhibitory activity from 28% to 82% compared to SB202190 and binding mode analysis revealed that the hydrogen-bond interactions with residues (Met109, Val30) were key point in inhibitor binding. Compound 5g clearly proved the best inhibitory action and could be further utilized for designing newer anti-cytokine agents and p38α MAP kinase potentially inhibitory action.

Involvement of the p38 MAPK-pHsp27 pathway in vascular hyporeactivity induced by obstructive jaundice in rats

Patients with obstructive jaundice are prone to develop cardiovascular complications during surgery. However, the underlying mechanisms remain largely unknown. The present study was aimed to investigate the role of p38 MAPK-pHsp27 pathway in vascular hyporesponsiveness induced by obstructive jaundice. Firstly, an experimental rat obstructive jaundice model was established by bile duct ligation (BDL). We found that the thoracic aorta rings isolated from BDL rats showed decreased response to norepinephrine and acetylcholine, while continuous intraperitoneal injection with SB203580, a selective P38 MAPK inhibitor, could significantly prevented BDL-induced hyporeactivity. Also, the immunohistochemistry and Western blot assays revealed that the up-regulation of pHsp27 and F-actin in thoracic aorta rings from BDL rats and bilirubin-treated vascular smooth muscle cells (VSMCs) were also inhibited by SB203580. Moreover, we identified that bilirubin could induced decreased cell proliferation of VSMCs by using CCK8 assay and which was also prevented by SB203580. All these data demonstrated that p38 MAPK-pHsp27 mediates vascular hyporesponsiveness in rats with obstructive jaundice by modulating the expression level of pHsp27 and F-actin, and that inhibition of p38 MAPK signaling could remodel the vascular activity.

The protective role of microRNA-21 against coxsackievirus B3 infection through targeting the MAP2K3/P38 MAPK signaling pathway

Background

The P38 mitogen-activated protein kinase (MAPK) pathway plays an essential role in CVB3-induced diseases. We previously demonstrated microRNA-21 has potential inhibitory effect on the MAP2K3 which locates upstream of P38 MAPK and was upregulated in mouse hearts upon CVB3 infection. However, the effect and underlying mechanism of miRNA-21 on CVB3 infection remain unclear.

Methods

We detected continuous changes of cellular miRNA-21 and P38 MAPK proteins expression profiling post CVB3 infection in vitro within 12 h. P38 MAPK signaling was inhibited by the specific inhibitor, small interfering RNA and miRNA-21 mimic in vitro, CVB3 replication, cell apoptosis rate and proliferation were detected. Viral load in the mice heart, cardiomyocyte apoptosis rate and histological of the heart were also detected in the mice model of viral myocarditis pretreated with miRNA-21-lentivirus.

Results

We observed significant upregulation of miRNA-21 expression followed by suppression of the MAP2K3/P38 MAPK signaling in CVB3-infected Hela cells. The inactivation of the MAP2K3/P38 MAPK signaling by P38 MAPK specific inhibitor, small interfering RNA against MAP2K3, or miRNA-21 overexpression significantly inhibited viral progeny release from CVB3-infected cells. Mechanistically, when compared with control miRNA, miRNA-21 showed no effect on capsid protein VP1 expression and viral load within host cells, while significantly reversing CVB3-induced caspase-3 activation and cell apoptosis rate, further promoting proliferation of infected cells, which indicates the inhibitory effect of miRNA-21 on CVB3 progeny release. In the in vivo study, when compared with control miRNA, miRNA-21 pretreatment remarkably inactivated the MAP2K3/P38 MAPK signaling in mice and protected them against CVB3 infection as evidenced by significantly alleviated cell apoptosis rate, reduced viral titers, necrosis in the heart as well as by remarkably prolonged survival time.

Conclusions

miRNA-21 were reverse correlated with P38 MAPK activation post CVB3 infection, miRNA-21 overexpression significantly inhibited viral progeny release and decreased myocytes apoptosis rate in vitro and in vivo, suggesting that miRNA-21 may serve as a potential therapeutic agent against CVB3 infection through targeting the MAP2K3/P38 MAPK signaling.

P38 MAPK signaling pathway mediates COM crystal-induced crystal adhesion change in rat renal tubular epithelial cells

The objective of the study is to clarify the mechanism of p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway in the change of crystal adhesion in rat renal tubular epithelial cells (NRK-52E) induced by calcium oxalate monohydrate (COM) crystals. NRK-52E cells were divided into COM crystal-treated group and control group according to whether the cell culture medium contains different concentrations of COM crystals. The concentrations of lactate dehydrogenase in the both group medium were determined after being cultured for 24 h. Protein and RNA were extracted from both cell groups after being cultured at different time points. SB239063, an inhibitor of the activation of p38 MAPK, was pretreated for 2 h before incubation with COM crystals. Western blotting and RT-qPCR were performed to confirm the expression levels of relative genes. All the experimental results were summarized and analyzed by SPSS 20.0 statistical analysis software. COM crystals (146 µg/cm²) could induce the expression levels of NLRP3, caspase-1 and interleukin-1β (IL-1β) significantly increased in NRK-52E cells. Compared with the control group cells, the transcription and translation levels of p38 MAPK-related molecule (such as p-p38) and adhesion molecules (such as osteopontin, hyaluronic acid and CD44) were significantly increased in COM crystal-treated cells and can be inhibited by SB239063 and NLRP3 gene silencing. This study demonstrated that the p38 MAPK signaling pathway mediated the COM crystal-induced crystal adhesion change in NRK-52E cells and required the involvement of NLRP3 inflammasome.

Celastrol suppresses experimental autoimmune encephalomyelitis via MAPK/SGK1-regulated mediators of autoimmune pathology

OBJECTIVE AND DESIGN

Multiple sclerosis (MS) is a debilitating autoimmune disease involving immune dysregulation of the pathogenic T helper 17 (Th17) versus protective T regulatory (Treg) cell subsets, besides other cellular aberrations. Studies on the mechanisms underlying these changes have unraveled the involvement of mitogen-activated protein kinase (MAPK) pathway in the disease process. We describe here a gene expression- and bioinformatics-based study showing that celastrol, a natural triterpenoid, acting via MAPK pathway regulates the downstream genes encoding serum/glucocorticoid regulated kinase 1 (SGK1), which plays a vital role in Th17/Treg differentiation, and brain-derived neurotrophic factor (BDNF), which is a neurotrophic factor, thereby offering protection against experimental autoimmune encephalomyelitis (EAE) in mice.

METHODS

We first tested the gene expression profile of splenocytes of EAE mice in response to the disease-related antigen, myelin oligodendrocyte glycoprotein (MOG), and then examined the effect of celastrol on that profile.

RESULTS

Interestingly, celastrol reversed the expression of many MOG-induced genes involved in inflammation and immune pathology. The MAPK pathway involving p38MAPK and ERK was identified as one of the mediators of celastrol action. It involved suppression of SGK1 but upregulation of BDNF, which then contributed to protection against EAE.

CONCLUSION

Our results not only provide novel insights into disease pathogenesis, but also offer promising therapeutic targets for MS.