14-3-3 interaction with phosphodiesterase 8A sustains PKA signaling and downregulates the MAPK pathway.

The cAMP/PKA and mitogen-activated protein kinase (MAPK) signaling cascade control many cellular processes and are highly regulated for optimal cellular responses upon external stimuli. Phosphodiesterase 8A (PDE8A) is an important regulator that inhibits signaling via cAMP-dependent PKA by hydrolyzing intracellular cAMP pool. Conversely, PDE8A activates the MAPK pathway by protecting CRAF/Raf1 kinase from PKA-mediated inhibitory phosphorylation at Ser259 residue, a binding site of scaffold protein 14-3-3. It still remains enigmatic as to how the cross-talk involving PDE8A regulation influences cAMP/PKA and MAPK signaling pathways. Here, we report that PDE8A interacts with 14-3-3ζ in both yeast and mammalian system, and this interaction is enhanced upon the activation of PKA, which phosphorylates PDE8A's Ser359 residue. Biophysical characterization of phospho-Ser359 peptide with 14-3-3ζ protein further supports their interaction. Strikingly, 14-3-3ζ reduces the catalytic activity of PDE8A, which upregulates the cAMP/PKA pathway while the MAPK pathway is downregulated. Moreover, 14-3-3ζ in complex with PDE8A and cAMP-bound regulatory subunit of PKA, RIα, delays the deactivation of PKA signaling. Our results define 14-3-3ζ as a molecular switch that operates signaling between cAMP/PKA and MAPK by associating with PDE8A.

Extracellular domain mutations of the EGF receptor differentially modulate high-affinity and low-affinity responses to EGF receptor ligands.

The EGF receptor is mutated in a number of cancers. In most cases, the mutations occur in the intracellular tyrosine kinase domain. However, in glioblastomas, many of the mutations are in the extracellular ligand binding domain. To determine what changes in receptor function are induced by such extracellular domain mutations, we analyzed the binding and biological response to the seven different EGF receptor ligands in three common glioblastoma mutants-R84K, A265V, and G574V. Our data indicate that all three mutations significantly increase the binding affinity of all seven ligands. In addition, the mutations increase the potency of all ligands for stimulating receptor autophosphorylation, phospholipase Cγ, Akt, and MAP kinase activity. In all mutants, the rank order of ligand potency seen at the wild-type receptor was retained, suggesting that the receptors still discriminate among the different ligands. However, the low-affinity ligands, EPR and EPG, did show larger than average enhancements of potency for stimulating Akt and MAPK but not receptor autophosphorylation and phospholipase Cγ activation. Relative to the wild-type receptor, these changes lead to an increase in the responsiveness of these mutants to physiological concentrations of ligands and an alteration in the ratio of activation of the different pathways. This may contribute to their oncogenic potential. In the context of recent findings, our data also suggest that so-called "high"-affinity biological responses arise from activation by isolated receptor dimers, whereas "low"-affinity biological responses require clustering of receptors which occurs at higher concentrations of ligand.

Establishing chronic models of age-related macular degeneration via long-term iron ion overload.

Age-related macular degeneration (AMD) is characterized by the degenerative senescence in the retinal pigment epithelium (RPE) and photoreceptors, which is accompanied by the accumulation of iron ions in the aging retina. However, current models of acute oxidative stress are still insufficient to simulate the gradual progression of AMD. To address this, we established chronic injury models by exposing the aRPE-19 cells, 661W cells, and mouse retina to iron ion overload over time. Investigations at the levels of cell biology and molecular biology were performed. It was demonstrated that long-term treatment of excessive iron ions induced senescence-like morphological changes, decreased cell proliferation, and impaired mitochondrial function, contributing to apoptosis. Activation of the mitogen-activated protein kinase (MAPK) pathway and the downstream molecules were confirmed both in the aRPE-19 and 661W cells. Furthermore, iron ion overload resulted in dry AMD-like lesions and decreased visual function in the mouse retina. These findings suggest that chronic exposure to overloading iron ions plays a significant role in the pathogenesis of retinopathy and provide a potential model for future studies on AMD.NEW & NOTEWORTHY To explore the possibility of constructing reliable research carriers on age-related macular degeneration (AMD), iron ion overload was applied to establish models in vitro and in vivo. Subsequent investigations into cellular physiology and molecular biology confirmed the presence of senescence in these models. Through this study, we hope to provide a better option of feasible methods for future researches into AMD.

Phase plane dynamics of ERK phosphorylation.

The extracellular signal-regulated kinase (ERK) controls multiple critical processes in the cell and is deregulated in human cancers, congenital abnormalities, immune diseases, and neurodevelopmental syndromes. Catalytic activity of ERK requires dual phosphorylation by an upstream kinase, in a mechanism that can be described by two sequential Michaelis-Menten steps. The estimation of individual reaction rate constants from kinetic data in the full mechanism has proved challenging. Here, we present an analytically tractable approach to parameter estimation that is based on the phase plane representation of ERK activation and yields two combinations of six reaction rate constants in the detailed mechanism. These combinations correspond to the ratio of the specificities of two consecutive phosphorylations and the probability that monophosphorylated substrate does not dissociate from the enzyme before the second phosphorylation. The presented approach offers a language for comparing the effects of mutations that disrupt ERK activation and function in vivo. As an illustration, we use phase plane representation to analyze dual phosphorylation under heterozygous conditions, when two enzyme variants compete for the same substrate.

Kinome profiling identifies MARK3 and STK10 as potential therapeutic targets in uveal melanoma.

Most uveal melanoma cases harbor activating mutations in either GNAQ or GNA11. Despite activation of the mitogen-activated protein kinase (MAPK) signaling pathway downstream of Gαq/11, there are no effective targeted kinase therapies for metastatic uveal melanoma. The human genome encodes numerous understudied kinases, also called the "dark kinome". Identifying additional kinases regulated by Gαq/11 may uncover novel therapeutic targets for uveal melanoma. In this study, we treated GNAQ-mutant uveal melanoma cell lines with a Gαq/11 inhibitor, YM-254890, and conducted a kinase signaling proteomic screen using multiplexed-kinase inhibitors followed by mass spectrometry. We observed downregulated expression and/or activity of 22 kinases. A custom siRNA screen targeting these kinases demonstrated that knockdown of microtubule affinity regulating kinase 3 (MARK3) and serine/threonine kinase 10 (STK10) significantly reduced uveal melanoma cell growth and decreased expression of cell cycle proteins. Additionally, knockdown of MARK3 but not STK10 decreased ERK1/2 phosphorylation. Analysis of RNA-sequencing and proteomic data showed that Gαq signaling regulates STK10 expression and MARK3 activity. Our findings suggest an involvement of STK10 and MARK3 in the Gαq/11 oncogenic pathway and prompt further investigation into the specific roles and targeting potential of these kinases in uveal melanoma.

Langerhans cell histiocytosis: NACHO update on progress, chaos, and opportunity on the path to rational cures.

Langerhans cell histiocytosis (LCH) is a myeloid neoplastic disorder characterized by lesions with CD1a-positive/Langerin (CD207)-positive histiocytes and inflammatory infiltrate that can cause local tissue damage and systemic inflammation. Clinical presentations range from single lesions with minimal impact to life-threatening disseminated disease. Therapy for systemic LCH has been established through serial trials empirically testing different chemotherapy agents and durations of therapy. However, fewer than 50% of patients who have disseminated disease are cured with the current standard-of-care vinblastine/prednisone/(mercaptopurine), and treatment failure is associated with long-term morbidity, including the risk of LCH-associated neurodegeneration. Historically, the nature of LCH-whether a reactive condition versus a neoplastic/malignant condition-was uncertain. Over the past 15 years, seminal discoveries have broadly defined LCH pathogenesis; specifically, activating mitogen-activated protein kinase pathway mutations (most frequently, BRAFV600E) in myeloid precursors drive lesion formation. LCH therefore is a clonal neoplastic disorder, although secondary inflammatory features contribute to the disease. These paradigm-changing insights offer a promise of rational cures for patients based on individual mutations, clonal reservoirs, and extent of disease. However, the pace of clinical trial development behind lags the kinetics of translational discovery. In this review, the authors discuss the current understanding of LCH biology, clinical characteristics, therapeutic strategies, and opportunities to improve outcomes for every patient through coordinated agent prioritization and clinical trial efforts.

Genome-wide identification of MAPK family in papaya (Carica papaya) and their involvement in fruit postharvest ripening.

BACKGROUND: Papaya (Carica papaya) is an economically important fruit cultivated in the tropical and subtropical regions of China. However, the rapid softening rate after postharvest leads to a short shelf-life and considerable economic losses. Accordingly, understanding the mechanisms underlying fruit postharvest softening will be a reasonable way to maintain fruit quality and extend its shelf-life. RESULTS: Mitogen-activated protein kinases (MAPKs) are conserved and play essential roles in response to biotic and abiotic stresses. However, the MAPK family remain poorly studied in papaya. Here, a total of nine putative CpMAPK members were identified within papaya genome, and a comprehensive genome-wide characterization of the CpMAPKs was performed, including evolutionary relationships, conserved domains, gene structures, chromosomal locations, cis-regulatory elements and expression profiles in response to phytohormone and antioxidant organic compound treatments during fruit postharvest ripening. Our findings showed that nearly all CpMAPKs harbored the conserved P-loop, C-loop and activation loop domains. Phylogenetic analysis showed that CpMAPK members could be categorized into four groups (A-D), with the members within the same groups displaying high similarity in protein domains and intron-exon organizations. Moreover, a number of cis-acting elements related to hormone signaling, circadian rhythm, or low-temperature stresses were identified in the promoters of CpMAPKs. Notably, gene expression profiles demonstrated that CpMAPKs exhibited various responses to 2-chloroethylphosphonic acid (ethephon), 1-methylcyclopropene (1-MCP) and the combined ascorbic acid (AsA) and chitosan (CTS) treatments during papaya postharvest ripening. Among them, both CpMAPK9 and CpMAPK20 displayed significant induction in papaya flesh by ethephon treatment, and were pronounced inhibition after AsA and CTS treatments at 16 d compared to those of natural ripening control, suggesting that they potentially involve in fruit postharvest ripening through ethylene signaling pathway or modulating cell wall metabolism. CONCLUSION: This study will provide some valuable insights into future functional characterization of CpMAPKs, and hold great potential for further understanding the molecular mechanisms underlying papaya fruit postharvest ripening.

The MAPK homolog, Smk1, promotes assembly of the glucan layer of the spore wall in S. cerevisiae.

Smk1 is a MAPK homolog in the yeast Saccharomyces cerevisiae that controls the postmeiotic program of spore wall assembly. During this program, haploid cells are surrounded by a layer of mannan and then a layer of glucan. These inner layers of the spore wall resemble the vegetative cell wall. Next, the outer layers consisting of chitin/chitosan and then dityrosine are assembled. The outer layers are spore-specific and provide protection against environmental stressors. Smk1 is required for the proper assembly of spore walls. However, the protective properties of the outer layers have limited our understanding of how Smk1 controls this morphogenetic program. Mutants lacking the chitin deacetylases, Cda1 and Cda2, form spores that lack the outer layers of the spore wall. In this study, cda1,2∆ cells were used to demonstrate that Smk1 promotes deposition of the glucan layer of the spore wall through the partially redundant glucan synthases Gsc2 and Fks3. Although Gsc2 is localized to sites of spore wall assembly in the wild type, it is mislocalized in the mother cell cytoplasm in the smk1∆ mutant. These findings suggest that Smk1 controls assembly of the spore wall by regulating the localization of Gsc2 during sporogenesis.

Orexin B protects dopaminergic neurons from 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity associated with reduced extracellular signal-regulated kinase phosphorylation.

BACKGROUND: The loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) is a major pathological hallmark of Parkinson's disease (PD). Orexin B (OXB) has been reported to promote the growth of DA neurons. However, the roles of OXB in the degeneration of DA neurons still remained not fully clear. METHODS: An in vivo PD model was constructed by administrating 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Pole test was performed to investigate the motor function of mice and the number of DA neurons was detected by immunofluorescence (IF). A PD cell model was established by treating SH-SY5Y cells with 1-methyl-4-phenylpyridinium (MPP+). OXB was added to the culture medium 2 h after MPP + treatment. Microscopic analysis was carried out to investigate the function of OXB in the cell model of PD 24 h after MPP + challenge. RNA-Seq analysis of the PD cell model was performed to explore the possible mechanisms. Western blot was used to detect the phosphorylation levels of extracellular signal-regulated kinase (ERK). RESULTS: OXB significantly decreased the DA neurons death caused by MPTP, alleviated MPP+-induced neurotoxicity in SH-SY5Y cells, and robustly enhanced the weight and motor ability of PD mice. Besides, RNA-Seq analysis demonstrated that the mitogen-activated protein kinase (MAPK) pathway was involved in the pathology of PD. Furthermore, MPP + led to increased levels of phosphorylation of ERK (p-ERK), OXB treatment significantly decreased the levels of p-ERK in MPP+-treated SH-SY5Y cells. CONCLUSIONS: This study demonstrated that OXB exerts a neuroprotective role associated with reduced ERK phosphorylation in the PD model. This suggests that OXB may have therapeutic potential for treatment of PD.

Icariin alleviates high-fat diet-induced nonalcoholic fatty liver disease via up-regulating miR-206 to mediate NF-κB and MAPK pathways.

Nonalcoholic fatty liver disease (NAFLD) is an abnormal lipid accumulation disease in hepatocytes. The existing drugs for NAFLD have some side effects, so new therapeutic agents are required to be explored. In this study, the effect and mechanism of icariin (ICA) on high-fat diet-induced NAFLD were investigated. Firstly, a high-fat diet was used to construct a NAFLD rat model and HepG2 cells were treated with 1 mM free fatty acid (FFA). After ICA treatment, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured; liver injury and lipid deposition were observed by H&E and Oil Red O staining; interleukin-1ß (IL-1ß), IL-12, and IL-6 were measured by enzyme-linked immunosorbent assay. Additionally, qRT-PCR and western blot were performed to detect miR-206 expression and NF-κB/MAPK pathway-related protein expression in liver tissues and cells. After a variety of trials, we discovered that compared with the NAFLD group, ICA significantly reduced ALT, AST, TBil, TG, TC, and LDL-C levels and increased HDL-C levels, and improved liver tissue injury and lipid deposition. Moreover, ICA reduced IL-1ß, IL-12, and IL-6 levels in liver tissues and cells as well as inhibited MAPK and NF-κB-related protein expression in the liver tissues. Notably, ICA could significantly increase miR-206 expression in liver tissues and cells. Further experiments confirmed that inhibition of miR-206 was able to reverse the effect of ICA on NAFLD. In conclusion, ICA can alleviate NAFLD by upregulating miR-206 to mediate NF-κB and MAPK pathways.

Cellular Energy Sensor Sirt1 Augments Mapk Signaling to Promote Hypoxia/Reoxygenation-Induced Catch-up Growth in Zebrafish Embryo.

Animal growth is blunted in adverse environments where catabolic metabolism dominates; however, when the adversity disappears, stunted animals rapidly catch up to age-equivalent body size. This phenomenon is called catch-up growth, which we observe in various animals. Since growth retardation and catch-up growth are sequential processes, catabolism or stress response molecules may remain active, especially immediately after growth resumes. Sirtuins (Sirt1-7) deacetylate target proteins in a nicotinamide adenine dinucleotide-dependent manner, and these enzymes govern diverse alleys of cellular functions. Here, we investigated the roles of Sirt1 and its close paralog Sirt2 in the hypoxia/reoxygenation-induced catch-up growth model using zebrafish embryos. Temporal blockade of Sirt1/2 significantly reduced the growth rate of the embryos in reoxygenation, but it was not evident in constant normoxia. Subsequent gene knockdown and chemical inhibition experiments demonstrated that Sirt1, but not Sirt2, was required for the catchup growth. Inhibition of Sirt1 significantly reduced the activity of mitogen-activated kinase (Mapk) of embryos in the reoxygenation condition. In addition, co-inhibition of Sirt1- and Igf-signaling did not further reduce the body growth or Mapk activation compared to those of the Igf-signaling-alone-inhibited embryos. Furthermore, in the reoxygenation condition, Sirt1- or Igf-signaling inhibition similarly blunted Mapk activity, especially in anterior tissues and trunk muscle, where the sirt1 expression was evident in the catching-up embryos. These results suggest that the catch-up growth requires Sirt1 action to activate the somatotropic Mapk pathway, likely by modifying the Igf-signaling.

The Interplay between the DNA Damage Response (DDR) Network and the Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway in Multiple Myeloma.

The DNA damage response (DDR) network and the mitogen-activated protein kinase (MAPK) signaling pathway are crucial mechanisms for the survival of all living beings. An accumulating body of evidence suggests that there is crosstalk between these two systems, thus favoring the appropriate functioning of multi-cellular organisms. On the other hand, aberrations within these mechanisms are thought to play a vital role in the onset and progression of several diseases, including cancer, as well as in the emergence of drug resistance. Here, we provide an overview of the current knowledge regarding alterations in the DDR machinery and the MAPK signaling pathway as well as abnormalities in the DDR/MAPK functional crosstalk in multiple myeloma, the second most common hematologic malignancy. We also present the latest advances in the development of anti-myeloma drugs targeting crucial DDR- and MAPK-associated molecular components. These data could potentially be exploited to discover new therapeutic targets and effective biomarkers as well as for the design of novel clinical trials. Interestingly, they might provide a new approach to increase the efficacy of anti-myeloma therapy by combining drugs targeting the DDR network and the MAPK signaling pathway.

p38α Mitogen-Activated Protein Kinase-An Emerging Drug Target for the Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is a neurodegenerative disorder, characterized by the formation of amyloid ß and tau protein aggregates in the brain, neuroinflammation, impaired cholinergic neurotransmission, and oxidative stress, resulting in the gradual loss of neurons and neuronal function, which leads to cognitive and memory deficits in AD patients. Chronic neuroinflammation plays a particularly important role in the progression of AD since the excessive release of proinflammatory cytokines from glial cells (microglia and astrocytes) induces neuronal damage, which subsequently causes microglial activation, thus facilitating further neurodegenerative changes. Mitogen-activated protein kinase (MAPK) p38α is one of the key enzymes involved in the control of innate immune response. The increased activation of the p38α MAPK pathway, observed in AD, has been for a long time associated not only with the maintenance of excessive inflammatory process but is also linked with pathophysiological hallmarks of this disease, and therefore is currently considered an attractive drug target for novel AD therapeutics. This review aims to summarize the current state of knowledge about the involvement of p38α MAPK in different aspects of AD pathophysiology and also provides insight into the possible therapeutic effects of novel p38α MAPK inhibitors, which are currently studied as potential drug candidates for AD treatment.

The molecular associations in clathrin-coated pit regulate ß-arrestin-mediated MAPK signaling downstream of µ-opioid receptor.

It has been thought that µ-opioid receptors (MOPs) activate the G protein-mediated analgesic pathway and ß-arrestin 2-mediated side effect pathway; however, ligands that only minimally recruit ß-arrestin 2 to MOPs may also cause opioid side effects. Moreover, such side effects have been induced in mutant mice lacking ß-arrestin 2 or expressing phosphorylation-deficient MOPs that do not recruit ß-arrestin 2. These findings raise the critical question of whether ß-arrestin 2 recruitment to MOP triggers side effects. Here, we show that ß-arrestin 1 and 2 are essential in the efficient activation of the Gi/o-mediated MAPK signaling at MOP. Moreover, the magnitude of ß-arrestin-mediated signals is not correlated with the magnitude of phosphorylation of the carboxyl-terminal of MOP, which is used to evaluate the ß-arrestin bias of a ligand. Instead, the molecular association with ß2-adaptin and clathrin heavy chain in the formation of clathrin-coated pits is essential for ß-arrestin to activate MAPK signaling. Our findings provide insights into G protein-coupled receptor-mediated signaling and further highlight a concept that the accumulation of molecules required for endocytosis is critical for activating intracellular signaling.

Revisiting the role of MAPK signalling pathway in plants and its manipulation for crop improvement.

The mitogen-activated protein kinase (MAPK) pathway is an important signalling event associated with every aspect of plant growth, development, yield, abiotic and biotic stress adaptation. Being a central metabolic pathway, it is a vital target for manipulation for crop improvement. In this review, we have summarised recent advancements in understanding involvement of MAPK signalling in modulating abiotic and biotic stress tolerance, architecture and yield of plants. MAPK signalling cross talks with reactive oxygen species (ROS) and abscisic acid (ABA) signalling events in bringing about abiotic stress adaptation in plants. The intricate involvement of MAPK pathway with plant's pathogen defence ability has also been identified. Further, recent research findings point towards participation of MAPK signalling in shaping plant architecture and yield. These make MAPK pathway an important target for crop improvement and we discuss here various strategies to tweak MAPK signalling components for designing future crops with improved physiology and phenotypes.

The cellular responses of corneal fibroblasts to cyclic stretching loads.

Mechanical signaling plays a crucial role in maintaining extracellular matrix (ECM) homeostasis in various structures. In this study, we investigated the responses of corneal fibroblasts to cyclic stretching loads using an in vitro cell culture system. Bovine corneal fibroblasts were cultured and subjected to equibiaxial cyclic strain of 15% for 72 h at a frequency of 0.25 Hz, with bovine skin fibroblasts used as a comparison. We explored various cellular behaviors, including morphological changes, cell proliferation, and metabolism in response to mechanical stretching loads. The expression of genes, protein secretion, and enzymatic activity for several major metalloproteinases was also determined through Q-PCR, Western blot, and gel zymography. Additionally, we investigated the involvement of mitogen-activated protein kinases (MAPKs) signaling pathways in the corneal fibroblasts when subjected to mechanical stimuli. Our findings revealed that, compared to skin fibroblasts, corneal fibroblasts were reluctant to morphological changes in response to a prolonged (72 h) and high-amplitude (15% of strain) cyclic stretching load. However, cyclic stretching loads stimulated the upregulation of MMP-2 expression in corneal fibroblasts via the MAPK signaling pathways involving extracellular signal-regulated kinase and p38. Together with a lack of upregulation in type I collagen expression, our results indicate the induction of the ECM degradation process in corneal fibroblasts in response to cyclic stretching. These findings emphasize the mechanoresponsive nature of corneal fibroblasts and shed light on the potential impact of intense mechanical stress on the cornea in both normal and pathological conditions such as keratoconus, providing valuable insights for understanding corneal mechanobiology.

Gremlin-1 promotes IL-1ß-stimulated chondrocyte inflammation and extracellular matrix degradation via activation of the MAPK signaling pathway.

The role and mechanism of Gremlin-1 in osteoarthritis (OA) were expected to be probed in this study. Firstly, an in vitro OA model was constructed by stimulating human chondrocyte cell line CHON-001 with IL-1ß. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were utilized for assessing the effect of IL-1ß with different concentrations (5, 10, and 20 ng/mL) on the activity and Gremlin-1 messenger RNA of CHON-001 cells, respectively. Besides, the influence of knocking down/over-expressing Gremlin-1 on the inflammatory factors (IL-6, TNF-α, IL-18 and PGE2), oxidative stress-related substances (malondialdehyde [MDA]; superoxide dismutase [SOD]; lactate dehydrogenase [LDH]), extracellular matrix (ECM) degradation-related proteins, and mitogen-activated protein kinase (MAPK) pathway proteins in IL-1ß-stimulated CHON-001 cells were tested by enzyme-linked immunosorbent assay, related kits, qRT-PCR, and western blot, respectively. IL-1ß inhibited CHON-001 cell proliferation and upregulated Gremlin-1 expression in a concentration-dependent manner. Overexpression of Gremlin-1 increased the IL-6, TNF-α, IL-18, PGE2, and MDA levels, enhanced the LDH activity, and decreased the SOD activity in IL-1ß-induced CHON-001 cells; while the effect of Gremlin-1 knockdown on the above factors was in contrast with that of the overexpression. Furthermore, overexpression of Gremlin-1 upregulated protein expression of matrix metalloproteinase (MMP)-3, MMP-13, and ADAMTS4 while downregulated protein expression of collagen III, aggrecan, and SOX-9 in IL-1ß-stimulated CHON-001 cells. Besides, overexpression of Gremlin-1 increased the p-p38/p38 value while decreased the p-JNK/JNK value in L-1ß-stimulated CHON-001 cells; however, knockdown of Gremlin-1 reversed the above results. Gremlin-1 may promote IL-1ß-stimulated CHON-001 cell inflammation and ECM degradation by activating the MAPK signaling pathway.

Anti-inflammatory Activity of Gegen Decoction and Its Modulatory Mechanism on the NF-κB and MAPK Signaling Pathways.

Gegen Decoction as anti-inflammatory medicine is used in clinic widespread, however the specific anti-inflammatory molecular mechanism of Gegen Decoction is still unclear. The purpose was to study the anti-inflammatory activity of Gegen Decoction in vivo and to research its anti-inflammatory molecular mechanism. The content of main essential components in Gegen Decoction were determined by HPLC method. The anti-inflammatory activity of Gegen Decoction was confirmed through in vivo animal experiments. Furthermore, RAW 264.7 cells were stimulated by lipopolysaccharides to induce inflammatory reaction, the modulatory effect of Gegen Decoction on the activation process of mitogen-activated protein kinases and nuclear factor-κB signaling pathways was investigated. The content of puerarin was the highest among all the index components. Gegen Decoction inhibited carrageenan-induced paw edema in rats and xylene-induced ear swelling in mice. Gegen Decoction had no obvious toxicity against RAW 264.7 cells at the concentrations of 10-40 mg/mL; significantly inhibited the release of nitric oxide, prostaglandin E2, tumor necrosis factor-α and interleukin-6; down-regulated the high expression of inflammatory proteins inducible nitric oxide synthase and cyclooxygenase-2. It inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs)/extracellular regulated protein kinases (ERK)/c-Jun N-terminal kinase (JNK), the degradation of nuclear factor-κB (NF-κB)/inhibitor of NF-κB-α (IκB-α) and the nuclear translocation of NF-κB/p65 into nucleus. Gegen Decoction exerts significant anti-inflammatory activity, mainly by blocking the activation of both MAPKs and NF-κB pathway.

IFI6 Downregulation Reverses Oxaliplatin Resistance of Colorectal Cancer Cells by Activating the ROS-Induced p38MAPK Signaling Pathway.

Oxaliplatin (OXA) is a usual chemotherapeutic agent applied in the colorectal cancer (CRC) clinical treatment. Interferon-alpha inducible protein 6 (IFI6) has been proved to promote proliferation and suppress apoptosis in several tumor cells, while the impacts of IFI6 on OXA resistance in CRC still need exploration. HCT116 and SW620 cells were used as the parental to obtain OXA-resistant cells. The influence of IFI6 on OXA sensitivity, cell proliferation and apoptosis were evaluated by overexpression or knockdown IFI6 in cells. In this work, we found that the level of IFI6 was significantly enhanced in HCT116/OXA and SW620/OXA cells as compared to the parental cells. Overexpression of IFI6 decreased the sensitivity of HCT116 and SW620 cells to OXA. However, knockdown of IFI6 enhanced the sensitivity of HCT116/OXA and SW620/OXA cells to OXA. And upregulated IFI6 promoted the proliferation and repressed apoptosis in HCT116 cells, while suppressed IFI6 markedly reduced proliferation and increased apoptosis in HCT116/OXA cells. Additionally, IFI6 suppressed the phosphorylation level of p38, and silenced IFI6 enhanced it. The addition of the p38 kinase inhibitor, SB203580, alleviated the decreased cell proliferation and increased apoptosis in HCT116/OXA cells. Suppressed IFI6 enhanced the reactive oxygen species (ROS) level in HCT116/OXA cells, and blockade of ROS with N-acetyl-L-cysteine (NAC) decreased the enhancement level of ROS and the phosphorylation level of the p38, which was induced by IFI6 down-regulation. We, therefore, implied that suppressed IFI6 reverses OXA-resistance of CRC cells via promoting the ROS-induced p38 mitogen-activated protein kinase (MAPK) signaling pathway.

SARM1 can be a potential therapeutic target for spinal cord injury.

Injury to the spinal cord is devastating. Studies have implicated Wallerian degeneration as the main cause of axonal destruction in the wake of spinal cord injury. Therefore, the suppression of Wallerian degeneration could be beneficial for spinal cord injury treatment. Sterile alpha and armadillo motif-containing protein 1 (SARM1) is a key modulator of Wallerian degeneration, and its impediment can improve spinal cord injury to a significant degree. In this report, we analyze the various signaling domains of SARM1, the recent findings on Wallerian degeneration and its relation to axonal insults, as well as its connection to SARM1, the mitogen-activated protein kinase (MAPK) signaling, and the survival factor, nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2). We then elaborate on the possible role of SARM1 in spinal cord injury and explicate how its obstruction could potentially alleviate the injury.