Mitogen-activated Protein Kinase Research Articles

Multiple Machine Learning Models, Molecular Subtyping and Singlecell Analysis Identify PANoptosis-related Core Genes and their Association with Subtypes in Crohn's Disease.

PANoptosis plays an important role in many inflammatory diseases. However, there are no reports on the association between PANoptosis and CD. This study used five machine learning algorithms - least absolute shrinkage and selection operator, support vector machine, random forest, decision tree and Gaussian mixture models - to construct CD's PANoptosis signature. Unsupervised hierarchical clustering analysis was used to identify PANoptosis-associated subgroups of CD. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were conducted to compare the PANoptosis-associated subgroups of CD among the potential biological mechanisms. Single sample GSEA was used to assess immune microenvironmental differences among the subgroups. The potential role of PANoptosis in CD was further explored using single-cell RNA-Seq (scRNA-Seq) for PANoptosis scoring, differential analysis, pseudotime analysis, cellular communication analysis and weighted gene co-expression network analysis (WGCNA) analysis. CD's PANoptosis signature consisted of seven genes: CEACAM6, CHP2, PIK3R1, CASP10, PSMB1, PSMB8 and UBC. The PANoptosis signature in multiple cohorts had a strong ability to recognise CD. The levels of immune cell infiltration and the vigour of the immune responses significantly varied between the two subpopulations of CD associated with PANoptosis. Multiple lines of evidence from the GO, KEGG, GSEA, GSVA, scRNA-Seq and WGCNA analyses suggested that I-kappaB kinase/NF- kappaB signalling, mitogen-activated protein kinase (MAPK), leukocyte activation and leukocyte migration were mechanisms closely associated with PANoptosis in CD. This study is the first to construct a PANoptosis signature with excellent efficacy in recognising CD. PANoptosis may mediate the process of CD through inflammatory and immune mechanisms, such as NF- kappaB, MAPK and leukocyte migration.

Emodin Inhibited MUC5AC Mucin Gene Expression via Affecting EGFR-MAPK-Sp1 Signaling Pathway in Human Airway Epithelial Cells.

The aim of this study was to evaluate emodin, a natural trihydroxyanthraquinone compound found in the roots and barks of several plants including rhubarb and buckthorn, might attenuate epidermal growth factor (EGF)-induced airway MUC5AC mucin gene expression. The human pulmonary mucoepidermoid NCI-H292 cells were pretreated with for 30 min and then stimulated with EGF for the following 24 h. The effect of emodin on EGF-induced mitogen-activated protein kinase (MAPK) signaling pathway was examined. As a result, emodin blocked the expression of MUC5AC mucin mRNA and production of mucous glycoprotein via suppressing the phosphorylation of EGF receptor (EGFR), phosphorylation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) 1 and 2 (MEK1/2), phosphorylation of p38 MAPK, phosphorylation of ERK 1/2 (p44/42), and the nuclear expression of specificity protein-1 (Sp1). These findings imply that emodin has a potential to mitigate EGF-stimulated mucin gene expression by inhibiting the EGFR-MAPK-Sp1 signaling pathway, in NCI-H292 cells.

Suppressing DUSP16 overexpression induced by ELK1 promotes neural progenitor cell differentiation in mouse models of Alzheimer's disease.

Emerged evidence indicated that stimulating hippocampal neurogenesis is a potential strategy for restoring cognition in AD. Mitogen-activated protein kinases (MAPKs) play an essential role in neurogenesis. Meanwhile, the enzymatic power of the phosphatases is much greater than that of kinases. Dual-specificity phosphatase 16 (DUSP16), known to as a phosphatase negatively regulate MAPKs, may be implicated in neural differentiation. Nevertheless, the effect of DUSP16 on cognitive disorders by stimulating neural progenitor cell (NPC) differentiation in AD mice remains unclear. Our study demonstrates an association between DUSP16 SNPs and clinical progression in individuals with mild cognitive impairment (MCI). Besides, increased DUSP16 expression was detected in both 3xTg and SAMP8 mouse models of AD, accompanied by NPC neural differentiation impairments. By silencing DUSP16, the induction of neural differentiation, synaptic transmission, and cognitive benefits were observed in both AD mice. Furthermore, DUSP16 was involved in the process of NPC differentiation through regulating c-Jun N-terminal kinase (JNK) phosphorylation and SOX2 expression. Moreover, ETS transcription factor (ELK1) was involved in the DUSP16 transcription, which resulted in the upregulation of DUSP16 at the state of AD. Our data uncovers a potential regulatory role for DUSP16 in adult hippocampal neurogenesis (AHN) and provides a possibility to find a novel strategy for AD intervention.

Delphinidin or α-amyrin attenuated liver steatosis and metabolic disarrangement in rats fed a high-fat diet.

Non-alcoholic fatty liver disease (NAFLD) is a liver pathology concomitant with metabolic disarrangement. This study assessed the therapeutic impacts of delphinidin, an anthocyanin, or α-amyrin, a pentacyclic triterpenoid, on NAFLD in rats and the underlying mechanisms involved. NAFLD was established by feeding a high-fat diet (HFD) for 10 weeks, either alone or in combination with delphinidin (40 mg/kg, oral) or α-amyrin (20 mg/kg, oral). Delphinidin or α-amyrin ameliorated the metabolic and histopathological perturbations induced by HFD. These compounds markedly attenuated NAFLD-induced hepatic steatosis, as evidenced by a substantial decrease in body weight, insulin resistance, and liver and adipose tissue indices. Alongside normalization of the atherogenic index, both improved HFD-mediated abnormalities in serum lipids, liver enzymes, leptin, and ghrelin levels. Moreover, their intervention activated the NFE2 like bZIP transcription factor 2 and heme oxygenase 1 pathways and abrogated HFD-triggered activation of mitogen-activated protein kinase 1 signaling. These remedies inhibited hepatic apoptosis and modulated the gene expression of lipogenic enzymes. Furthermore, histological analysis corroborated the suppression of lipid accumulation and amelioration of hepatic architecture in the treated rats. Our findings highlight the hepatoprotective value of delphinidin or α-amyrin against NAFLD and related metabolic diseases through their insulin-sensitizing, anti-inflammatory, antioxidant, and antiapoptotic effects.

Falcarindiol improves functional recovery and alleviates neuroinflammation after spinal cord injury by inhibiting STAT/MAPK signaling pathways

Spinal cord injury (SCI) is a devastating trauma in the central nervous system (CNS), leading to motor and sensory impairment. Neuroinflammation is one of the critical contributors to the progression of secondary injury. Falcarindiol has been reported to efficaciously mitigate lipopolysaccharide (LPS)-mediated inflammation in RAW 264.7 cells. The role of falcarindiol in SCI recovery remains unclear. In this present study, traumatic SCI mice models and LPS-stimulated murine microglia cell line (BV2 cells) were performed to explore the pharmacological effects and the underlying mechanisms of falcarindiol in improving SCI repair with detection of motor function recovery, morphological changes, numbers of survival neurons and protein expression levels of inflammation or apoptosis-related proteins. Our study found that falcarindiol intervention could promote motor function recovery and reduce spinal cord tissue damage in mice following SCI. Mechanistically, falcarindiol intervention suppressed apoptosis-driven neuronal cell death and mitigated inflammatory reactions following SCI. Additionally, falcarindiol inhibited the activation of signal transducer and activator of transcription (STAT) and mitogen-activated protein kinases (MAPK) signaling pathways in vivo and in vitro. This suppression of STAT and MAPK activation by falcarindiol was reversed by STAT3 agonist Colivelin TFA and MAPK agonist C16-PAF in BV2 cells, respectively. Moreover, the study further demonstrated that the anti-inflammation role of falcarindiol was obstructed by Colivelin TFA but not by C16-PAF in LPS-stimulated BV2 cells, suggesting that falcarindiol may efficaciously ameliorate neuroinflammation through inhibiting the activation of STAT signaling pathway following SCI. Collectively, our study indicates that falcarindiol may be a novel drug candidate for the treatment and management of SCI.

Impact of Curcumin on the IL-17A-Mediated p53-Fibrinolytic System: Mouse Proteomics and Integrated Human Fibrosis scRNAseq Insights.

Acute lung injury (ALI) is primarily driven by an intense inflammation in the alveolar epithelium. Key to this is the pro-inflammatory cytokine, Interleukin 17 (IL-17), which influences pulmonary immunity and modifies p53 function. The direct role of IL-17A in p53-fibrinolytic system is still unclear, it is important to evaluate this mechanism to regulate the ALI progression to idiopathic pulmonary fibrosis (IPF). C57BL/6 mice, exposed to recombinant IL-17A protein and treated with curcumin, provided insight into IL-17A mechanisms and curcumin's potential for modulating early pulmonary fibrosis stages. A diverse methodology, including proteomics, single-cell RNA sequencing (scRNA-seq) integration, molecular, and Schroedinger approach were utilized. In silico approaches facilitated the potential interactions between curcumin, IL-17A, and apoptosis-related proteins. A notable surge in the expression levels of IL-17A, p53, and fibrinolytic components such as Plasminogen Activator Inhibitor-1 (PAI-I) was discerned upon the IL17A exposure in mouse lungs. Furthermore, the enrichment of pathways and differential expression of proteins underscored the significance of IL-17A in governing downstream regulatory pathways such as inflammation, NF-kappaB signaling, Mitogen-Activated Protein Kinases (MAPK), p53, oxidative phosphorylation, JAK-STAT, and apoptosis. The integration of scRNA-seq data from 20 IPF and 10 control lung specimens emphasized the importance of IL-17A mediated downstream regulation in PF patients. A potent immuno-pharmacotherapeutic agent, curcumin, demonstrated a substantial capacity to modulate the lung pathology and molecular changes induced by IL-17A in mouse lungs. Human IPF single cell data integration confirmed the effects of IL-17A mediated fibrinolytic components in ALI to IPF progression.

Immunomodulatory Effects of a Prebiotic Formula with 2'-Fucosyllactose and Galacto- and Fructo-Oligosaccharides on Cyclophosphamide (CTX)-Induced Immunosuppressed BALB/c Mice via the Gut-Immune Axis.

Obejectives: This study explored the immunomodulatory effects of a prebiotic formula consisting of 2'-fucosyllactose (2'-FL), galacto-oligosaccharides (GOSs), and fructo-oligosaccharides (FOSs) (hereinafter referred to as 2FGF) in cyclophosphamide (CTX)-induced immunosuppressed BALB/c mice and its underlying mechanisms. Methods: Sixty healthy female BALB/c mice were randomly divided into the following groups: normal control (NC) group; CTX treatment (CTX) group; 2FGF low-dose (2FGF-L) group; 2FGF medium-dose (2FGF-M) group; and 2FGF high-dose (2FGF-H) group. An immunosuppressed model was established in the 2FGF-H group by intraperitoneal injection of 80 mg/kg CTX. After 30 days of 2FGF intervention, peripheral blood, spleen tissue, thymus tissue, and intestinal tissue from the mice were collected and analyzed. The changes in weight and food intake of the mice were recorded weekly. Hematoxylin-eosin (HE) staining was used to observe the histological change of the spleen tissue. Enzyme-linked immunosorbent assay (ELISA) was employed to detect cytokine levels in peripheral blood. Flow cytometry was used to analyze T lymphocyte subgroup ratio of splenic lymphocytes. Western blot analysis was conducted on intestinal tissues to assess the expression of proteins involved in the tight junction, toll-like receptor 4 (TLR4), mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathways. Additionally, molecular techniques were used to analyze the intestinal microbiota. Results: The results showed that 2FGF restored CTX-induced splenic injury, increased the number of splenic T lymphocytes, and elevated serum cytokines such as interleukin-4 (IL-4) and IL-10. In the intestine, 2FGF upregulated the expression of intestinal epithelial tight junction proteins such as Claudin-1 and zonula occludens 1 (ZO-1), thereby enhancing intestinal barrier function and activating the MAPK and NF-κB pathways via TLR4. Furthermore, 2FGF elevated the α-diversity (Shannon and Simpson indices) of the gut microbiota in CTX-induced immunosuppressed mice, enriching bacteria species positively correlated with anti-inflammatory cytokines (e.g., IL-4) such as g_Streptomyces and g_Bacillus and negatively correlated with pro-inflammatory cytokines (e.g., IL-1β) such as g_Saccharomyces. The results suggest that 2FGF may enhance immunity via the gut-immune axis. Conclusions: The 2FGF prebiotic formula showed an immunomodulatory effect in CTX-induced immunosuppressed mice, and the mechanism of which might involve optimizing the gut flora, enhancing intestinal homeostasis, strengthening the intestinal barrier, and promoting the expression of immune factors by regulating the TLR-4/MAPK/NF-κB pathway.

Upcycling olive pomace into pectic elicitors for plant immunity and disease protection

Olive oil production generates substantial quantities of pomace, which are often disposed of in soil, leading to adverse effects on agriculture and the environment. Furthermore, climate change exacerbates plant diseases and promotes the use of toxic phytochemicals in agriculture. However, olive mill wastes can have high potential as reusable and valuable bioresources. Using diluted ethanol, an environmentally friendly solvent, we extracted a fraction containing short and long oligogalacturonides, short arabino-oligosaccharides and polysaccharides. The obtained extract elicited key features of plant innate immunity in Arabidopsis seedlings, including the phosphorylation of mitogen-activated protein kinases MPK3 and MPK6 and the upregulation of defence genes such as CYP81F2, WRKY33, WRKY53, and FRK1. Notably, pretreatment of adult Arabidopsis and tomato plants with the olive pomace extract primed defence responses and enhanced their resistance to the phytopathogens Botrytis cinerea and Pseudomonas syringae. Our results highlight the opportunity to upcycle the two-phase olive pomace collected at the late stage of olive oil campaign, in low-cost and sustainable glycan elicitors, contributing to reducing the use of chemically synthesized pesticides.

Hypoxia-inducible Factor-1α Pathway in Cerebral Ischemia: From Molecular Mechanisms to Therapeutic Targets.

Ischemic injury to the brain can result in a variety of life-threatening conditions, mortality, or varying degrees of disability. Hypoxia-inducible factor 1α (HIF 1α), an oxygen- sensitive transcription factor that controls the adaptive metabolic response to hypoxia, is a critical constituent of cerebral ischemia. It participates in numerous processes, such as metabolism, proliferation, and angiogenesis, and plays a major role in cerebral ischemia. Through the use of a number of different search engines like Scopus, PubMed, Bentham, and Elsevier databases, a literature review was carried out for investigating the pharmacological modulation of HIF-1α pathways for the treatment of cerebral ischemia. Various signalling pathways, such as Mitogen-activated protein kinase (MAPK), Janus kinase/ signal transducers and activators (JAK/STAT), Phosphoinositide-3-kinase (PI3-K), and cAMPresponse element binding protein (CREB) play a vital role in modulation of HIF-1α pathway, which helps in preventing the pathogenesis of cerebral ischemia. The pharmacological modulation of the HIF-1α pathway via various molecular signalling pathways, such as PI3-K, MAPK, CREB, and JAK/STAT activators, offer a promising prospect for future interventions and treatment for cerebral ischemia.

Comparison of sGC activator and sGC stimulator in 5/6 nephrectomized rats on high-salt-diet.

Soluble guanylate cyclase (sGC) stimulators and activators are known to enhance kidney function in various models of chronic kidney disease (CKD) by increasing cyclic guanosine monophosphate (cGMP). Their differential effects on CKD progression, particularly under conditions of oxidative stress, remain unexplored by direct comparative studies. We conducted a side-by-side comparison using 5/6 nephrectomized rats on a high salt diet (5/6Nx+HSD) to evaluate the efficacy of the sGC stimulator BAY 41-8543 and the sGC activator BAY 60-2770 in CKD progression. BAY 41-8543 (1mg/kg; twice daily) and BAY 60-2770 (1mg/kg; once daily) were administered by gavage for 11 weeks. The 5/6Nx+HSD model led to increased plasma creatinine, proteinuria, and blood pressure. Both BAY 41-8543 and BAY 60-2770 significantly reduced systolic and diastolic blood pressure to a similar extent but did not improve renal function parameters. Notably, BAY 60-2770 reduced renal fibrosis, including interstitial fibrosis and glomerulosclerosis, whereas BAY 41-8543 did not. These antifibrotic effects of BAY 60-2770 were independent of blood pressure reduction. Proteomic analysis revealed that BAY 60-2770 corrected the upregulation of 9 proteins associated with apoptosis and fibrosis, including Caspase-3, MKK6 (Mitogen-Activated Protein Kinase Kinase 6), Prdx5 (Peroxiredoxin-5), in the 5/6Nx+HSD group. In contrast, BAY 41-8543 had no significant impact on these proteins. sGC activators were more effective than sGC stimulators in reducing renal fibrosis in 5/6 nephrectomized rats on a high salt diet, and this effect was due to modulation of apoptosis-associated proteins beyond the control of blood pressure.

Synergistic Effect of Resveratrol and Paclitaxel in the Treatment of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a lethal and aggressive cancer due to exposure to asbestos since this carcinogen is still being used in industrial buildings and housing in several countries. Untreated MPM has a median survival time of 12 months, and most people die within 24 months after diagnosis. If caught early, surgery may be performed. Treatment option for palliative care is limited using platinum with pemetrexed. Malignant transformation of a cell is attributed to a series of genetic and epigenetic events involving alterations in several oncogenes, tumor suppressor genes, and others. Different anticancer and antioxidants with anticancer properties were tested individually and in combination to find the best synergistic effect in killing MSTO-211H, a lung mesothelioma cell line used as model of MPM. Once the combination was identified, assays and staining methods such as MTT, Rhodamine123, Hoechst 33342, Nuclear ID Red/Green, and Western Blot were performed to identify different proteins involved in apoptosis and cell signaling cascade to proof the cytotoxic effect of the combine anticancer and antioxidant treatment. Combination of Paclitaxel (PAC) at 3 µM and Resveratrol (RSV) at 62.5 µM showed synergistic effect on MSTO-211H cells by causing inhibition of epidermal growth factor receptor (EGFR), inhibition of mitogen activated protein kinases (MEKs) 1-4, inhibition of programmed death ligand-1 (PDL-1), inhibition of cell cycle proteins, and induction of caspases 3-8. This study provided possible potential application of using RSV as a chemo-enhancing compound with PAC in the treatment of MPM.

Genome-Wide Identification of MKK Gene Family and Response to Hormone and Abiotic Stress in Rice.

Mitogen-activated protein kinase (MAPK/MPK) cascades are pivotal and highly conserved signaling modules widely distributed in eukaryotes; they play essential roles in plant growth and development, as well as biotic and abiotic stress responses. With the development of sequencing technology, the complete genome assembly of rice without gaps, T2T (Telomere-to-Telomere)-NIP (version AGIS-1.0), has recently been released. In this study, we used bioinformatic approaches to identify and analyze the rice MPK kinases (MKKs) based on the complete genome. A total of seven OsMKKs were identified, and their physical and chemical properties, chromosome localization, gene structure, subcellular localization, phylogeny, family evolution, and cis-acting elements were evaluated. OsMKKs can be divided into four subgroups based on phylogenetic relationships, and the family members located in the same evolutionary branch have relatively similar gene structures and conserved domains. Quantitative real-time PCR (qRT-PCR) revealed that all OsMKKs were highly expressed in rice seedling leaves. The expression levels of all OsMKKs were more or less altered under exogenous hormone and abiotic stress treatments, with OsMKK1, OsMKK6, and OsMKK3 being induced under almost all treatments, while the expression of OsMKK4 and OsMKK10-2 was repressed under salt and drought treatments and IAA treatment, respectively. In this study, we also summarized the recent progress in rice MPK cascades, highlighted their diverse functions, and outlined the potential MPK signaling network, facilitating further studies on OsMKK genes and rice MPK cascades.

Interaction between CD244 and SHP2 regulates inflammation in chronic obstructive pulmonary disease via targeting the MAPK/NF-κB signaling pathway.

This study delved into the interplay between CD244 and Src Homology 2 Domain Containing Phosphatase-2 (SHP2) in chronic obstructive pulmonary disease (COPD) pathogenesis, focusing on apoptosis and inflammation in cigarette smoke extract (CSE)-treated human bronchial epithelial (HBE) cells. Analysis of the GSE100153 dataset identified 290 up-regulated and 344 down-regulated differentially expressed genes (DEGs). Weighted gene co-expression network analysis (WGCNA) highlighted the turquoise module had the highest correlation with COPD samples. Functional enrichment analysis linked these DEGs to critical COPD processes and pathways like neutrophil degranulation, protein kinase B activity, and diabetic cardiomyopathy. Observations on CD244 expression revealed its upregulation with increasing CSE concentrations, suggesting a dose-dependent relationship with inflammatory cytokines (IL-6, IL-8, TNF-α). CD244 knockdown mitigated CSE-induced apoptosis and inflammation, while overexpression exacerbated these responses. Co-immunoprecipitation (Co-IP) confirmed the physical interaction between CD244 and SHP2, emphasizing their regulatory connection. Analysis of Concurrently, the Nuclear Factor-kappa B (NF-κB) and Mitogen-activated protein kinase (MAPK) signaling pathways showed that modulating CD244 expression impacted key pathway components (p-JNK, p-IKKβ, p-ERK, p-P38, p-lkBα, p-P65), an effect reversed upon SHP2 knockdown. These findings underscore the pivotal role of the CD244/SHP2 axis in regulating inflammatory and apoptotic responses in CSE-exposed HBE cells, suggesting its potential as a therapeutic target in COPD treatment strategies.

EPHB4-RASA1 Inhibition of PIEZO1 Ras Activation Drives Lymphatic Valvulogenesis.

EPHB4 (ephrin receptor B4) and the RASA1 (p120 Ras GTPase-activating protein) are necessary for the development of lymphatic vessel (LV) valves. However, precisely how EPHB4 and RASA1 regulate LV valve development is unknown. In this study, we examine the mechanisms by which EPHB4 and RASA1 regulate the development of LV valves. We used LV-specific inducible EPHB4-deficient mice and EPHB4 knockin mice that express a form of EPHB4 that is unable to bind RASA1 yet retains protein tyrosine kinase activity (EPHB4 2YP) to study the role of EPHB4 and RASA1 in LV valve development in the embryo and LV valve maintenance in adults. We also used human dermal lymphatic endothelial cells in vitro to study the role of EPHB4 and RASA1 as regulators of LV valve specification induced by oscillatory shear stress, considered the trigger for LV valve specification in vivo. LV valve specification, continued valve development postspecification, and LV valve maintenance were blocked upon induced loss of EPHB4 in LV. LV specification and maintenance were also impaired in EPHB4 2YP mice. Defects in LV development were reversed by inhibition of the Ras-MAPK (mitogen-activated protein kinase) signaling pathway. In human dermal lymphatic endothelial cells, loss of expression of EPHB4 or its ephrin b2 ligand, loss of expression of RASA1, and inhibition of physical interaction between EPHB4 and RASA1 resulted in dysregulated oscillatory shear stress-induced Ras-MAPK activation and impaired expression of LV specification markers that could be rescued by Ras-MAPK pathway inhibition. The same results were observed when human dermal lymphatic endothelial cells were stimulated with the Yoda1 agonist of the PIEZO1 oscillatory shear stress sensor. Although Yoda1 increased the number of LV valves when administered to wild-type embryos, it did not increase LV valve number when administered to EPHB4 2YP embryos. EPHB4 is necessary for LV valve specification, continued valve development postspecification, and valve maintenance. LV valve specification requires physical interaction between EPHB4 and RASA1 to limit activation of the Ras-MAPK pathway in lymphatic endothelial cells. Specifically, EPHB4-RASA1 physical interaction is necessary to dampen Ras-MAPK activation induced through the PIEZO1 oscillatory shear stress sensor. These findings reveal the mechanism by which EPHB4 and RASA1 regulate the development of LV valves.

The Candida auris Hog1 MAP kinase is essential for the colonization of murine skin and intradermal persistence.

Candida auris is a World Health Organization fungal priority pathogen and an urgent public health threat recognized by the Centers for Disease Control and Prevention. C. auris has a unique ability to colonize human skin. It also persists on abiotic surfaces in healthcare environments for an extended period of time. These attributes facilitate the inter- and intrahospital clonal transmission of C. auris. Therefore, understanding C. auris skin colonization mechanisms is critical for infection control, especially in hospitals and nursing homes. However, despite its profound clinical relevance, the molecular and genetic basis of C. auris skin colonization mechanisms are poorly understood. Herein, we present data on the identification of the Hog1 MAP kinase as a key regulator of C. auris skin colonization. These findings lay the foundation for further characterization of unique mechanisms that promote fungal persistence on human skin.

Distinct mechanisms of type 3 secretion system recognition control LTB4 synthesis in neutrophils and macrophages.

Leukotriene B4 (LTB4) is an inflammatory lipid produced in response to pathogens that is critical for initiating the inflammatory cascade needed to control infection. However, during plague, Yersinia pestis inhibits the timely synthesis of LTB4 and subsequent inflammation. Using bacterial mutants, we previously determined that Y. pestis inhibits LTB4 synthesis via the action of the Yop effector proteins that are directly secreted into host cells through a type 3 secretion system (T3SS). Here, we show that the T3SS is the primary pathogen associated molecular pattern (PAMP) required for production of LTB4 in response to both Yersinia and Salmonella. However, we also unexpectantly discovered that T3SS-mediated LTB4 synthesis by neutrophils and macrophages require the activation of two distinctly different host signaling pathways. We identified that phagocytosis and the NLRP3/CASP1 inflammasome significantly impact LTB4 synthesis by macrophages but not neutrophils. Instead, the SKAP2/PLC signaling pathway is required for T3SS-mediated LTB4 production by neutrophils. Finally, while recognition of the T3SS is required for LTB4 production, we also discovered that a second unrelated PAMP-mediated signal activates the MAP kinase pathway needed for synthesis. Together, these data demonstrate significant differences in the host factors and signaling pathways required by macrophages and neutrophils to quickly produce LTB4 in response to bacteria. Moreover, while macrophages and neutrophils might rely on different signaling pathways for T3SS-dependent LTB4 synthesis, Y. pestis has evolved virulence mechanisms to counteract this response by either leukocyte to inhibit LTB4 synthesis and colonize the host.

AIBP Protects Müller Glial Cells Against Oxidative Stress-Induced Mitochondrial Dysfunction and Reduces Retinal Neuroinflammation.

Glaucoma, an optic neuropathy with the loss of retinal ganglion cells (RGCs), is a leading cause of irreversible vision loss. Oxidative stress and mitochondrial dysfunction have a significant role in triggering glia-driven neuroinflammation and subsequent glaucomatous RGC degeneration in the context of glaucoma. It has previously been shown that apolipoprotein A-I binding protein (APOA1BP or AIBP) has an anti-inflammatory function. Moreover, Apoa1bp-/- mice are characterized by retinal neuroinflammation and RGC loss. In this study, we found that AIBP deficiency exacerbated the oxidative stress-induced disruption of mitochondrial dynamics and function in the retina, leading to a further decline in visual function. Mechanistically, AIBP deficiency-induced oxidative stress triggered a reduction in glycogen synthase kinase 3β and dynamin-related protein 1 phosphorylation, optic atrophy type 1 and mitofusin 1 and 2 expression, and oxidative phosphorylation, as well as the activation of mitogen-activated protein kinase (MAPK) in Müller glia dysfunction, leading to cell death and inflammatory responses. In vivo, the administration of recombinant AIBP (rAIBP) effectively protected the structural and functional integrity of retinal mitochondria under oxidative stress conditions and prevented vision loss. In vitro, incubation with rAIBP safeguarded the structural integrity and bioenergetic performance of mitochondria and concurrently suppressed MAPK activation, apoptotic cell death, and inflammatory response in Müller glia. These findings support the possibility that AIBP promotes RGC survival and restores visual function in glaucomatous mice by ameliorating glia-driven mitochondrial dysfunction and neuroinflammation.

Negative regulation of APC/C activation by MAPK-mediated attenuation of Cdc20Slp1 under stress

Mitotic anaphase onset is a key cellular process tightly regulated by multiple kinases. The involvement of mitogen-activated protein kinases (MAPKs) in this process has been established in Xenopus egg extracts. However, the detailed regulatory cascade remains elusive, and it is also unknown whether the MAPK-dependent mitotic regulation is evolutionarily conserved in the single-cell eukaryotic organisms such as fission yeast (Schizosaccharomyces pombe). Here, we show that two MAPKs in S. pombe indeed act in concert to restrain anaphase-promoting complex/cyclosome (APC/C) activity upon activation of the spindle assembly checkpoint (SAC). One MAPK, Pmk1, binds to and phosphorylates Slp1Cdc20, the co-activator of APC/C. Phosphorylation of Slp1Cdc20 by Pmk1, but not by Cdk1, promotes its subsequent ubiquitylation and degradation. Intriguingly, Pmk1-mediated phosphorylation event is also required to sustain SAC under environmental stress. Thus, our study establishes a new underlying molecular mechanism of negative regulation of APC/C by MAPK upon stress stimuli, and provides a previously unappreciated framework for regulation of anaphase entry in eukaryotic cells.

Supplementing exogenous xylanase improves the liver antioxidant capacity and immune response of Tibetan sheep fed wheat-based diets

Xylanase is a heteropolysaccharide found in the plant cell wall, which aids in the absorption and utilisation of nutrients. When embedded in animal feed, it enhances nutrient availability, leading to improved animal performance. The aim of this study was to explore the effect of xylanase supplementation in wheat-based feeds on the hepatic development, antioxidant capacity, and immune response in Tibetan sheep. Sixty healthy, weaned, non-neutered male lambs (19.35 ± 2.18 kg) were randomly assigned to two equal groups (n = 30 per group). Dietary treatments were: basal diet (H group), and basal diet with 0.2% xylanase supplementation (E group). After a 10–day adaptation period, the feeding trial was carried out for 90 days. The live weight, morphology, antioxidant capacity and immune response were measured. The differential genes in liver were identified by RNA-sequencing. Our results showed that the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were significantly higher in E group than in H group (p < 0.05). Enzyme-linked immunosorbent assay (ELISA) revealed that immunoglobulin A (IgA), IgM, and IgG were significantly higher in E group than in H group (p < 0.05). The hepatocytes of sheep fed xylanase diet showed arranged radially into hepatic plates cantered around the central vein, and the plates linked with each other to form a lost-like structure. A total of 4,509 differential genes (DEGs) were identified, among which 4,427 were up-regulated and 82 down-regulated. Additionally, the expression of antioxidant-related genes in cluding catalase (CAT), superoxide dismutase 1 (SOD1), oxidation resistance 1 (OXR1) and glutathione peroxidase 2 (GPX2), and immunity-related gene including mitogen-activated protein kinase 1 (MAPK1), signal transducer and activator of transcription 5B (STAT5B), janus kinase 3 (JAK3) and jun proto-oncogene (JUN) were verified using the quantitative reverse transcription polymerase chain reaction (qRT-PCR). Conclusion: In conclusion, dietary 0.2% xylanase supplementation promoted hepatic antioxidant capacity and immune response via modulating the expression of functional genes in Tibetan sheep.

VE-1 regulation of MAPK signaling controls sexual development in Neurospora crassa.

Sexual reproduction generates new gene combinations and novel phenotypic traits and facilitates evolution. Induction of sexual development in fungi is often regulated by environmental conditions, such as the presence of light and nutrients. The velvet protein complex coordinates internal cues and environmental signals to regulate development. We have found that VE-1, a component of the velvet complex, regulates transcription during sexual development in the fungus Neurospora crassa. VE-1 regulates the transcription of many genes, including those involved in mitogen-activated protein kinase (MAPK) signaling pathways that are essential in the regulation of sexual development, and regulates the activity of the MAPK pathway. Our findings provide valuable insights into how fungi respond to environmental signals and integrate them into their reproductive processes.