Mitogen-activated Protein Kinase Family Research Articles

Modulation of Glycolipid Metabolism in T2DM Rats by Rubus Irritans Focke Extract: Insights from Metabolic Profiling and ERK/IRS-1 signaling pathway

Ethnopharmacological RelevanceThe extracellular regulated protein kinase (ERK) plays a crucial role in the mitogen-activated protein kinase (MAPK) family, influencing apoptosis, proliferation, and differentiation. It connection to the insulin (INS) signaling cascade and the development of type 2 diabetes mellitus (T2DM) has been established. Rubus irritans Focke, an indispensable herb in Chinese Tibetan medicine for diabetes mellitus treatment, lacks a comprehensive understanding of its effects and pharmacological mechanisms in T2DM. Aim of the studyThis study aimed to elucidate the effects of Rubus irritans Focke extract (Rife) on a T2DM rat model, exploring its impact on glycemic and lipid metabolism, histopathological changes, and its potential targeting of the extracellular regulated protein kinase/insulin receptor substrate-1 (ERK/IRS-1) signaling pathway. Materials and MethodsA T2DM rat model was induced by streptozotocin (STZ) injection (40 mg/kg) in high-fat diet-fed (HFD) male Wistar rats. Rife and metformin (Met) were administered for 4 weeks, and glycemic, lipid metabolism indices, and histopathological changes were assessed. Protein expression of ERK, IRS-1 in rat liver tissues was examined to evaluate the impact on the ERK/IRS-1 pathway. ResultsRife reducing hepatic ERK and IRS-1 protein expression in T2DM rats. Untargeted metabolomics identified 13 potential biomarkers and 4 differential metabolic pathways related to glycolipid metabolism disorders. ConclusionsRife demonstrated improved glycolipid metabolism in T2DM rats by inhibiting the ERK/IRS-1 related signaling pathway and influencing multiple metabolic pathways. This study provides valuable insights into the potential therapeutic mechanisms of Rife in the context of T2DM.

Overexpression of TaMPK3 enhances freezing tolerance by increasing the expression of ICE-CBF-COR related genes in the Arabidopsis thaliana.

Mitogen-activated protein kinases (MAPKs) play important roles in plant stress response. As a major member of the MAPK family, MPK3 has been reported to participate in the regulation of chilling stress. However, the regulatory function of wheat (Triticum aestivum ) mitogen-activated protein kinase TaMPK3 in freezing tolerance remains unknown. Dongnongdongmai No.1 (Dn1) is a winter wheat variety with strong freezing tolerance; therefore, it is important to explore the mechanisms underlying this tolerance. In this study, the expression of TaMPK3 in Dn1 was detected under low temperature and hormone treatment. Gene cloning, bioinformatics and subcellular localisation analyses of TaMPK3 in Dn1 were performed. Overexpressed TaMPK3 in Arabidopsis thaliana was obtained, and freezing tolerance phenotype observations, physiological indices and expression levels of ICE-C-repeat binding factor (CBF)-COR -related genes were determined. In addition, the interaction between TaMPK3 and TaICE41 proteins was detected. We found that TaMPK3 expression responds to low temperatures and hormones, and the TaMPK3 protein is localised in the cytoplasm and nucleus. Overexpression of TaMPK3 in Arabidopsis significantly improves freezing tolerance. TaMPK3 interacts with the TaICE41 protein. In conclusion, TaMPK3 is involved in regulating the ICE-CBF-COR cold resistance module through its interaction with TaICE41, thereby improving freezing tolerance in Dn1 wheat.

Identification of potential JNK3 inhibitors through virtual screening, molecular docking and molecular dynamics simulation as therapeutics for Alzheimer's disease.

Alzheimer's disease (AD) is a complex neurological disorder and no effective drug is available for its treatment. Numerous pathological conditions are believed to be responsible for the initiation and development of AD including c-Jun N-terminal kinases (JNKs). The JNKs are one of the enzymes from the mitogen-activated protein kinase (MAPK) family that controls the phosphorylation of various transcription factors on serine and threonine residues, and hold significant responsibilities in tasks like gene expression, cell proliferation, differentiation, and apoptosis. Since, JNK3 is primarily expressed in the brain hence its increased levels in the brain are associated with the AD pathology promoting neurofibrillary tangles, senile plaques, neuroinflammation, and nerve cell apoptosis. The current research work is focused on the development of novel JNK inhibitors as therapeutics for AD employing a structure-based virtual screening (SBVS) approach. The ZINC database (14634052 compounds) was investigated after employing pan assay interference (PAINs), drug-likeness, and diversity picking filter to distinguish molecules interacting with JNK3 by following three docking precision criteria: High Throughput Virtual Screening (HTVS), Standard Precision (SP), and Extra Precision (XP) & MMGBSA. Five lead molecules showed a better docking score in the range of -13.091 to -14.051kcal/mol better than the reference compound (-11.828kcal/mol). The lead compounds displayed acceptable pharmacokinetic properties and were subjected to molecular dynamic simulations of 100ns and binding free energy calculations. All the lead molecules showed stable RMSD and hydrogen bond interactions throughout the trajectory. The ∆GMM/PBSA_total score for the lead compounds ZINC220382956, ZINC147071339, ZINC207081127, ZINC205151456, ZINC1228819126, and CC-930 was calculated and found to be -31.39, -42.8, -37.04, -39.01, -36.5, -34.16kcal/mol, respectively. Thus, it was concluded that the lead molecules identified in these studies have the potential to be explored as potent JNK3 inhibitors.

Pirfenidone ameliorates alcohol-induced promotion of breast cancer in mice.

Alcohol consumption increases the risk of breast cancer and promotes cancer progression. Alcohol exposure could affect both processes of the mammary carcinogenesis, namely, the cell transformation and onset of tumorigenesis as well as cancer aggressiveness including metastasis and drug resistance/recurrence. However, the cellular and molecular mechanisms underlying alcohol tumor promotion remain unclear. There are four members of the mammalian p38 mitogen-activated protein kinase (MAPK) family, namely, p38α, p38β, p38γ and p38δ. We have previously demonstrated alcohol exposure selectively activated p38γ MAPK in breast cancer cells in vitro and in vivo. Pirfenidone (PFD), an antifibrotic compound approved for the treatment of idiopathic pulmonary fibrosis, is also a pharmacological inhibitor of p38γ MAPK. This study aimed to determine whether PFD is useful to inhibit alcohol-induced promotion of breast cancer. Female adolescent (5 weeks) MMTV-Wnt1 mice were exposed to alcohol with a liquid diet containing 6.7% ethanol. Some mice received intraperitoneal (IP) injection of PFD (100 mg/kg) every other day. After that, the effects of alcohol and PFD on mammary tumorigenesis and metastasis were examined. Alcohol promoted the progression of mammary tumors in adolescent MMTV-Wnt1 mice. Treatment of PFD blocked tumor growth and alcohol-promoted metastasis. It also significantly inhibited alcohol-induced tumorsphere formation and cancer stem cell (CSC) population. PFD inhibited mammary tumor growth and alcohol-promoted metastasis. Since PFD is an FDA-approved drug, the current findings may be helpful to re-purpose its application in treating aggressive breast cancer and alcohol-promoted mammary tumor progression.

Role of reactive oxygen species (ROS) signaling pathway in the wound-induced spore formation of Pyropia yezoensis

Asexual spore formation of Pyropia yezoensis significantly impacts yield. After mechanical sectioning of leafy thalli into fragments, somatic cells rapidly develop into a large number of wound-induced spores (WIS, a form of asexual spores). Recent studies on P. yezoensis have demonstrated a notable increase in reactive oxygen species (ROS) during this process; however, the regulatory mechanism underlying this ROS signaling remains largely unclear. This paper shows that in P. yezoensis, ROS signals play a crucial role in WIS formation. When treated with the ROS-producing enzyme NADPH oxidase inhibitor diphenyleneiodonium chloride, P. yezoensis thalli fragments strongly repressed WIS formation, accompanied by a significant decrease of ROS levels, malondialdehyde contents, and activities of NADPH oxidase and antioxidant enzymes. The expression levels of respiratory burst oxidase homolog genes, aquaporin protein genes, superoxide dismutase genes, glutathione S-transferase genes, and glutathioneperoxidase genes were also decreased, thus inhibiting WIS formation. As an upstream signal, ROS promote ion exchange and metabolism both inside and outside of cells within the first 12 h of wound stress. Following 12 h of wound stress, transcriptional activation of specific genes associated with cell cycle progression—which promotes cell division and dedifferentiation under normal conditions—was also blocked by diphenyleneiodonium chloride. In addition, the generated ROS signals also regulated the expression of mitogen-activated protein kinase family genes under wound stress. Overall, this study provides novel insights into the molecular mechanism underlying the ROS signaling regulation of WIS formation in P. yezoensis.

The Role of the Dysregulated JNK Signaling Pathway in the Pathogenesis of Human Diseases and Its Potential Therapeutic Strategies: A Comprehensive Review.

JNK is named after c-Jun N-terminal kinase, as it is responsible for phosphorylating c-Jun. As a member of the mitogen-activated protein kinase (MAPK) family, JNK is also known as stress-activated kinase (SAPK) because it can be activated by extracellular stresses including growth factor, UV irradiation, and virus infection. Functionally, JNK regulates various cell behaviors such as cell differentiation, proliferation, survival, and metabolic reprogramming. Dysregulated JNK signaling contributes to several types of human diseases. Although the role of the JNK pathway in a single disease has been summarized in several previous publications, a comprehensive review of its role in multiple kinds of human diseases is missing. In this review, we begin by introducing the landmark discoveries, structures, tissue expression, and activation mechanisms of the JNK pathway. Next, we come to the focus of this work: a comprehensive summary of the role of the deregulated JNK pathway in multiple kinds of diseases. Beyond that, we also discuss the current strategies for targeting the JNK pathway for therapeutic intervention and summarize the application of JNK inhibitors as well as several challenges now faced. We expect that this review can provide a more comprehensive insight into the critical role of the JNK pathway in the pathogenesis of human diseases and hope that it also provides important clues for ameliorating disease conditions.

Involvement of Sep38β in the Insecticidal Activity of Bacillus thuringiensis against Beet Armyworm, Spodoptera exigua (Lepidoptera).

The p38 mitogen-activated protein kinases (MAPKs) are associated with insect immunity, tissue repair, and the insecticidal activity of Bacillus thuringiensis (Bt). Here, a p38 MAPK family gene (Sep38β) was identified from Spodoptera exigua. Among the developmental stages, the transcription level of Sep38β was the highest in egg, followed by that in prepupa and pupa. Sep38β expression peaked in Malpighian tubules and the hemolymph of fifth instar larvae. Knockdown of Sep38β or injection of SB203580 (a p38 MAPK inhibitor) significantly downregulated the SeDUOX expression and reactive oxygen species (ROS) level in the midgut, accounting for deterioration of the midgut to scavenge pathogens and enhancement of Bt insecticidal activity. In conclusion, all the results demonstrate that Sep38β regulates the immune-related ROS level in the insect midgut, which suppresses the insecticidal activity of Bt against S. exigua by 17-22%. Our study highlights that Sep38β is essential for insect immunity and the insecticidal activity of Bt to S. exigua and is a potential target for pest control.

Genome-Wide Identification, Evolution, and Expression Analysis of the MAPK Gene Family in Rosaceae Plants

Mitogen-activated protein kinases (MAPKs) are crucial regulators in coping with abiotic and biotic stresses, including drought, salinity, fungi, and pathogens. However, little is known about the characteristics, evolution process, and functional divergence of the MAPK gene family in Rosaceae plants. A total of 97 MAPK members were identified in six Rosaceae species, including 12 genes in Fragaria vesca, 22 genes in Malus domestica, 23 genes in Pyrus bretschneideri, 12 genes in Prunus mume, 14 genes in Prunus persica, and 14 genes in Rosa chinensis. All MAPK members of six Rosaceae plants were categorized into four clusters by the phylogenetic relationship analysis. Collinearity analysis discovered that both segmental duplication and tandem duplication contributed to the expansion of MAPK family genes in Rosaceae plants. And the analysis of motifs and gene structures indicated that the evolution of the MAPK gene family was highly conserved among phylogenetic clusters in Rosaceae species. In addition, the dN/dS rates of MAPK paralogous gene pairs were below one, suggesting the MAPK gene family in Rosaceae was driven by purifying selective pressure. Furthermore, functional divergence analysis discovered that 14 amino acid residues were detected as potentially key sites for functional divergence of MAPK family genes between different cluster pairs, specifically Type I functional divergence. The analysis of functional distance indicated that cluster C retained more of the original functional features, while cluster B exhibited functional specialization. Moreover, the expression profiles revealed that PmMAPK8, PmMAPK9, and PmMAPK10 were both highly expressed under drought stress and low temperature conditions. This study aims to comprehensively analyze the evolutionary process and functional analyses of the MAPK gene family in Rosaceae plants, which will lay the foundation for future studies into MAPK genes of Rosaceae in response to drought and cold stress.

Abstract C137: Tumor-selective, chaperone-mediated targeting of ERK5 (MAPK7)

Abstract Extracellular signal-regulated kinase 5 (ERK5 or MAPK7) belongs to the mitogen-activated protein kinase family and has been associated with a wide range of cellular functions, including cell proliferation, migration, differentiation and survival. ERK5 has also been implicated in the onset and progression of several types of cancer. Importantly, studies comparing pharmacological inhibition versus genetic deletion or knockdown of ERK5 have revealed that it also possesses kinase activity-independent functions, suggesting that an ERK5 protein degrader approach may be required to completely block all ERK5-regulated signaling. To this end, we have explored applying Chaperone-mediated Protein Degradation (CHAMP) technology to target ERK5 protein. CHAMPs are heterobifunctional small molecules that mediate protein degradation by inducing proximity between a target protein and the HSP90 chaperone complex, resulting in target ubiquitination and degradation by the proteasome. Due to HSP90 being highly activated in cancer cells, CHAMPs also preferentially accumulate in tumors relative to normal tissues, resulting in an improved therapeutic index versus typical inhibitors. In order to chemically induce ERK5 degradation, CHAMP compounds were synthesized by covalently coupling ERK5- and HSP90-binding moieties through a short linker. CHAMP treatment of cancer cell lines resulted in formation of an ERK5-CHAMP-HSP90 ternary complex and subsequent proteasome-dependent ERK5 degradation. This in turn resulted in inhibition of ERK5 downstream signaling, leading to cell growth inhibition, cell cycle arrest and apoptosis in a panel of cancer cell lines. Further, in mouse xenograft models, CHAMPs displayed prolonged pharmacokinetics in tumors relative to plasma and normal tissues and strongly inhibited tumor growth at tolerated doses. Based on these findings, ERK5-targeted CHAMPs represents a promising new approach to disrupt the entire function of ERK5 for the of treatment cancer. Citation Format: Kevin P Foley, Xiangcai Yang, Wei Yin, Mengmeng Xu, Mingkai Wang, Qinglin Ding, Yan Dai, Haoxin Zhou, Ignazia Tusa, Alessio Menconi, Zoe Lombardi, Alessandro Tubita, Thomas L Prince, Guoqiang Wang, Elisabetta Rovida, Weiwen Ying. Tumor-selective, chaperone-mediated targeting of ERK5 (MAPK7) [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C137.

PBK correlates with prognosis, immune escape and drug response in LUAD

PBK (PDZ-binding kinase) is a protein-coding gene that encodes a serine/threonine protein kinase associated with the dual-specific mitogen-activated protein kinase (MAPKK) family. Overexpression of this gene is closely linked to tumor development. In this study, we aimed to investigate the role of PBK in lung adenocarcinoma (LUAD) progression, prognosis, and immune evasion. We conducted a pan-cancer analysis of PBK to examine its expression and prognostic value. In the LUAD cohort, we analyzed PBK expression, prognosis, mutational features, and immune infiltration in groups with different PBK expression levels. We constructed a PBK-associated genomic model, integrated it into a nomogram, and compared high and low-risk subgroups. In our pan-cancer analysis, PBK was significantly upregulated, particularly in LUAD patients, and displayed poor prognosis. The high PBK expression group had many deletion mutations but still showed gene upregulation. Immune infiltration analysis indicated that PBK-triggered immune escape in the high expression group might relate to antigen presentation, dendritic cell, and CD8+ T cell infiltration. We constructed a 5-gene prognostic model and a nomogram to quantify individual survival probabilities. The PBK-associated gene prognostic model reliably predicted patient prognosis and drug response. Our findings offer new insights into PBK-induced immune escape and targeted therapy during LUAD development, providing valuable suggestions for clinical treatment approaches.

The endocrine disruptor cadmium modulates the androgen-estrogen receptors ratio and induces inflammatory cytokines in luminal (A) cell models of breast cancer.

Breast cancer (BC) is the most common malignancy that affects women, and it is, to date, their leading cause of death. Luminal A molecular subtype accounts for 40% of BC and is characterized by hormone receptors positive/human epidermal growth factor 2 expression and current treatment consists of surgery plus aromatase inhibitor therapy. Interestingly, several studies demonstrated that the heavy metal cadmium (Cd), classified as a group 1 human carcinogen and widely spread in the environment, exerts estrogen-like activities in several tissues and suggested an intriguing relationship between increased Cd exposure and BC incidence. Thus, aim of this study was to evaluate effects of Cd on Luminal A BC estrogen receptor (ER) positive/progesterone receptor positive cell models in vitro to characterize the mechanism(s) involved in breast cell homeostasis disruption. T47D and MCF7 were exposed to Cd (0.5-1 µM) for 6-24 h to evaluate potential alterations in: cells viability, steroid receptors and intracellular signaling by western blot. Moreover, we evaluated the expression of inflammatory cytokines interleukin by RT-PCR. Our results showed a significant induction of androgen receptor (AR) and an increased AR/ER ratio. Further, Cd exposure increased pro-inflammatory cytokines interleukin (IL)6, IL8 and tumor necrosis factor α levels. Finally, as previously demonstrated by our group, Cd alters pathways such as mitogen-activated protein kinase family and protein kinase B. In conclusion, our study demonstrates that Cd modifies the expression and pattern of ERs and AR in BC cell lines, suggesting an alteration of BC cells homeostasis, likely predisposing to a carcinogenetic microenvironment.

A pan-cancer analysis of the MAPK family gene and their association with prognosis, tumor microenvironment, and therapeutic targets.

The mitogen-activated protein kinases family of genes plays a crucial role in a wide range of inflammatory responses in the human body. The MAPK family of genes includes ERK, ERK5, JNK, P-38 mitogen-activated protein kinases. However, the correlation between MAPK family gene expression and pan-cancer prognosis, as well as the tumor microenvironment, has not been extensively studied. This study integrated multiple bioinformatics analysis methods to assess the expression and prognostic value of MAPK family genes, as well as their relationship with tumor microenvironment in patients with pan-cancer. The results showed that ERK, JNK, and P-38 MAPK expression were found to be significantly upregulated in rectum adenocarcinoma (READ), colon adenocarcinoma/rectum adenocarcinoma esophageal carcinoma (COADREAD), and kidney renal clear cell carcinoma (KIRC), and significantly downregulated in acute myeloid leukemia. And the results revealed good prognostic results for ERK, JNK, and P-38 MAPK in READ, COADREAD, and KIRC. We observed significant positive correlation between MAPK family gene expression and immune scores especially dendritic cells in READ, COADREAD, and KIRC. And we observed that the expression levels of MAPK family genes were significantly correlated with the expression of immune-related genes, such as CXCL1, CXCL2, CXCL8, CXCR1, CXCR2, CTLA-4, CD80, CD86, and CD28, suggesting their important role in regulating immune infiltrates and tumor progression. Therefore, our study suggested that MAPK family gene plays an important role in regulating immune infiltrates and tumor progression.

Transcriptome analysis of Haemaphysalis flava female using Illumina HiSeq 4000 sequencing: de novo assembly, functional annotation and discovery of SSR markers

BackgroundTicks are ectoparasites capable of directly damaging their hosts and transmitting vector-borne diseases. The ixodid tick Haemaphysalis flava has a broad distribution that extends from East to South Asia. This tick is a reservoir of severe fever with thrombocytopenia syndrome virus (SFTSV) that causes severe hemorrhagic disease, with cases reported from China, Japan and South Korea. Recently, the distribution of H. flava in South Korea was found to overlap with the occurrence of SFTSV.MethodsThis study was undertaken to discover the molecular resources of H. flava female ticks using the Illumina HiSeq 4000 system, the Trinity de novo sequence assembler and annotation against public databases. The locally curated Protostome database (PANM-DB) was used to screen the putative adaptation-related transcripts classified to gene families, such as angiotensin-converting enzyme, aquaporin, adenylate cyclase, AMP-activated protein kinase, glutamate receptors, heat shock proteins, molecular chaperones, insulin receptor, mitogen-activated protein kinase and solute carrier family proteins. Also, the repeats and simple sequence repeats (SSRs) were screened from the unigenes using RepeatMasker (v4.0.6) and MISA (v1.0) software tools, followed by the designing of SSRs flanking primers using BatchPrimer 3 (v1.0) software.ResultsThe transcriptome produced a total of 69,822 unigenes, of which 46,175 annotated to the homologous proteins in the PANM-DB. The unigenes were also mapped to the EuKaryotic Orthologous Groups (KOG), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) specializations. Promiscuous presence of protein kinase, zinc finger (C2H2-type), reverse transcriptase, and RNA recognition motif domains was observed in the unigenes. A total of 3480 SSRs were screened, of which 1907 and 1274 were found as tri- and dinucleotide repeats, respectively. A list of primer sequences flanking the SSR motifs was detailed for validation of polymorphism in H. flava and the related tick species.ConclusionsThe reference transcriptome information on H. flava female ticks will be useful for an enriched understanding of tick biology, its competency to act as a vector and the study of species diversity related to disease transmission.Graphical abstract

In Silico Analysis of the MAPK Gene Family in Cabbage and Its Expression during Development and Stress Response

Cabbage is often affected by an adverse environment and pathogens during its growth, resulting in a decline in yield and quality. Mitogen-activated protein kinases (MAPKs) play crucial roles in the development process, hormones, abiotic and biotic stresses, and cell division. So far, MAPKs have been characterized in various species. However, no systematic analysis of the MAPK family in cabbage has been performed. A total of 24 BoMAPK genes were identified and renamed according to Arabidopsis homologs; they were unevenly distributed on nine chromosomes. According to the conserved domain and phylogenetic relationship, BoMAPKs were divided into four subgroups, of which three belonged to subgroup A, four to subgroup B, three to subgroup C, and fourteen to subgroup D, respectively. There were 13 segmental duplication events in the cabbage genome. The Ka/Ks ratios for duplicated gene pairs of the MAPK family were less than 0.2, indicating that these BoMAPK genes have undergone purification selection in evolution. There were various cis-acting elements associated with stress, hormones, and development found in the promoter regions of most BoMAPK genes. Transcriptome data showed a high expression of BoMAPK3, BoMAPK4.1, and BoMAPK6.1 genes in various tissues. BoMAPK17.2, BoMAPK20.1 and BoMAPK20.2 were significantly induced by Plasmodiophora brassicae, as evidenced in the quantitative PCR (RT-qPCR) analysis, revealing their enormous potential to regulate stress response. RT-qPCR results showed how the transcriptional levels of BoMAPK genes varied substantially under abiotic stress at different time points. These analysis results provide a reference to further explore the function and evolution of BoMAPK genes in cabbage.

The impact of extremely low-temperature changes on fish: A case study on migratory bony fishes (Takifugu fasciatus)

The impact of low temperatures on the aquaculture industry is of paramount importance as an environmental factor, resulting in significant losses worldwide in the breeding sector owing to sudden cold waves or seasonal fluctuations. Consequently, understanding the mechanisms through which fish adapt to low-temperature stress has become a crucial research focus in aquaculture. This research aims to investigate the effects of different temperature gradients (25, 19, and 13 °C) and time intervals (0, 6, 24, and 96 h) on the histomorphology, antioxidant enzyme activity, mitogen-activated protein kinase (MAPK) pathway, and lipidomics of the liver in Takifugu fasciatus. These findings reveal that exposure to low temperatures disrupts the liver’ structure, causing fibrosis, which intensifies with prolonged exposure and decreased temperatures. Additionally, cold stress induces oxidative stress, leading to lipid peroxidation and triggering activation of the antioxidant enzyme system. Concurrently, the MAPK family proteins (extracellular signal-regulated kinase [ERK], c-Jun N-terminal kinase [JNK], and P38MAPK) undergo phosphorylation and regulate the expression of genes associated with lipid synthesis, breakdown, and transport. Lipidomic analysis under low-temperature stress identified both upregulated and downregulated lipid metabolites. Notably, specific phospholipid metabolites such as phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidylcholine were significantly upregulated, and demonstrated reparative capabilities. This study suggests that T.fasciatus potentially regulates lipid metabolism through the MAPK family, improving lipid composition, and facilitating the repair of temperature-induced cell membrane damage. These results highlight the pivotal role of lipids in the response of T.fasciatus response to low-temperature stress, with phospholipid metabolites demonstrating potential as feed additives. Overall, this study enhances the understanding of low-temperature tolerance mechanisms in osteichthyan fish, offering valuable insights for further investigations.

Design, Synthesis, and Biological Evaluation of Proteolysis-Targeting Chimeras as Highly Selective and Efficient Degraders of Extracellular Signal-Regulated Kinase 5.

Extracellular signal-regulated kinase 5 (ERK5) is recognized as a key member of the mitogen-activated protein kinase family and is involved in tumor growth, migration, and angiogenesis. However, the results of ERK5 inhibition in multiple studies are controversial, and a highly specific ERK5-targeting agent is required to confirm physiological functions. Using proteolysis-targeting chimera technology, we designed the selective ERK5 degrader PPM-3 and examined its biological effect on cancer cells. Interestingly, the selective degradation of ERK5 with PPM-3 did not influence tumor cell growth directly. Based on proteomics analysis, the ERK5 deletion may be associated with tumor immunity. PPM-3 influences tumor development by affecting the differentiation of macrophages. Therefore, PPM-3 is an effective small-molecule tool for studying ERK5 and a promising immunotherapy drug candidate.

Abstract P418: Antigen-presenting Cell-specific MAP-kinase Signaling Contributes To Inflammation And Salt-sensitivity Of Blood Pressure In Humans

Salt-sensitivity of blood pressure (SSBP) is defined by the changes in blood pressure in concert with salt intake/depletion. SSBP affects 50 percent of hypertensive and 25 percent of normotensive individuals and is an independent risk for stroke and cardiovascular death in both groups. We recently found that phosphorylation of STAT3 and SMAD3 in antigen-presenting cells plays an important role in developing SSBP. We hypothesized that mitogen-activated protein kinases (MAPKs) signaling plays an important role in activating/phosphorylating JAK-STAT-SMAD and contributes to salt-sensitivity of blood pressure. We isolated monocytes from eleven healthy individuals and treated them with either normal salt (NS) or high salt (HS) and performed bulk-RNA-sequencing. The bulk-RNA transcriptomic data analysis suggested that out of 21 members of the MAPK family, eighteen were upregulated (1.7-fold) in monocytes exposed to high salt. Among these, MAPK7 (NS:818.18±54.96; HS:1473.18±151.50) and MAPKAPK2 (NS:3977.81±286.67; HS:6222.63±440.32) were significantly upregulated. In additional experiments, we enrolled eleven hypertensive patients and phenotyped them for salt-sensitivity using a rapid salt-load and depletion inpatient protocol. Blood was collected at baseline, after salt loading, and depletion, and CITE-Seq was performed on isolated PBMCs. The data analysis showed that MAPK7 and MAPKAPK2 expressions mirror the blood pressure changes following salt loading and depletion in salt-sensitive but not in salt-resistant patients. Moreover, we found a positive correlation between MAPKAPK2 expression and the pulse pressure ((PP) r=0.52, p=0.033) after salt-load. Epoxyeicosatrienoic acid (EET) has been shown to activate MAPKs resulting in inhibiting ENAC activity. The data showed a strong positive correlation between MAPK7 expression and levels of EETs in plasma (r=0.70, p=0.036), and urine (r=0.68, p=0.045) after salt-load. These results from bulk-RNA and single-cell CITE-Seq data indicate that MAPKs play an important role in human SSBP.

Unraveling effective extracellular signal-regulated kinase 2 inhibitors: a de novo drug design strategy enhanced by in-depth in silico analyses

Extracellular signal-regulated kinase 2 (ERK-2) is a serine/threonine protein kinase in eukaryotic cells and belongs to the mitogen-activated protein kinase (MAPK) family. An activated form of ERK-2 phosphorylates substrates in the nucleus or cytoplasm and causes specific proteins to be expressed or activated, regulating cell proliferation, differentiation and other functions. Caffeic acid (3,4 − dihydroxy cinnamic acid), as previously reported, directly interacts with ERK-2 and reduces its effects in vitro. It is also reported to have a variety of pharmacological effects, including anti-inflammatory, immunomodulatory, antioxidant and anticancer activities. In the current study, a deep-learning protocol was employed to develop effective 100 compounds by modifying the chemical structure of DHC to improve its inhibitory performance against ERK-2. Calculations of physicochemical properties for those compounds revealed that 20 compounds had drug scores better than DHC (≥ 80%). Following that, molecular docking calculations were performed on the selected compounds and DHC. The obtained data revealed that five compounds had docking scores better than DHC (≥ −5.9 kcal/mol). Moreover, data from molecular mechanics and the Poisson − Boltzmann surface area (MM/PBSA) binding energy over 200 ns MD simulation confirmed that Cmd-1 and Cmd-4 exhibited higher stability with ΔG binding of −40.8 and −49.1 kcal/mol, respectively, which is better than DHC (−35.1 kcal/mol). Finally, various energetic and structural studies showed the high stability of the two generated compounds within the active site of ERK-2. This study highlights the potential use of Cmd-1 and Cmd-4 as promising anti-ERK-2 drug candidates. Communicated by Ramaswamy H. Sarma

Differential Modulation of the Phosphoproteome by the MAP Kinases Isoforms p38α and p38β.

The p38 members of the mitogen-activated protein kinases (MAPKs) family mediate various cellular responses to stress conditions, inflammatory signals, and differentiation factors. They are constitutively active in chronic inflammatory diseases and some cancers. The differences between their transient effects in response to signals and the chronic effect in diseases are not known. The family is composed of four isoforms, of which p38α seems to be abnormally activated in diseases. p38α and p38β are almost identical in sequence, structure, and biochemical and pharmacological properties, and the specific unique effects of each of them, if any, have not yet been revealed. This study aimed to reveal the specific effects induced by p38α and p38β, both when transiently activated in response to stress and when chronically active. This was achieved via large-scale proteomics and phosphoproteomics analyses using stable isotope labeling of two experimental systems: one, mouse embryonic fibroblasts (MEFs) deficient in each of these p38 kinases and harboring either an empty vector or vectors expressing p38αWT, p38βWT, or intrinsically active variants of these MAPKs; second, induction of transient stress by exposure of MEFs, p38α-/-, and p38β-/- MEFs to anisomycin. Significant differences in the repertoire of the proteome and phosphoproteome between cells expressing active p38α and p38β suggest distinct roles for each kinase. Interestingly, in both cases, the constitutive activation induced adaptations of the cells to the chronic activity so that known substrates of p38 were downregulated. Within the dramatic effect of p38s on the proteome and phosphoproteome, some interesting affected phosphorylation sites were those found in cancer-associated p53 and Hspb1 (HSP27) proteins and in cytoskeleton-associated proteins. Among these, was the stronger direct phosphorylation by p38α of p53-Ser309, which was validated on the Ser315 in human p53. In summary, this study sheds new light on the differences between chronic and transient p38α and p38β signaling and on the specific targets of these two kinases.

The significance of ERK5 catalytic-independent functions in disease pathways.

Extracellular signal-regulated kinase 5 (ERK5), also known as BMK1 or MAPK7, represents a recent addition to the classical mitogen-activated protein kinase (MAPK) family. This family includes well-known members such as ERK1/2, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK), as well as atypical MAPKs such as ERK3, ERK4, ERK7 (ERK8), and Nemo-like kinase (NLK). Comprehensive reviews available elsewhere provide detailed insights into ERK5, which interested readers can refer to for in-depth knowledge (Nithianandarajah-Jones et al., 2012; Monti et al., Cancers (Basel), 2022, 14). The primary aim of this review is to emphasize the essential characteristics of ERK5 and shed light on the intricate nature of its activation, with particular attention to the catalytic-independent functions in disease pathways.