Activation and function of the MAPKs and their substrates, the MAPK-activated protein kinases. Microbiol Mol Biol Rev. 2011;75:50-83. [PMID: 21372320 DOI: 10.1128/mmbr.00031-10]

Functions of SRPK, CLK and DYRK kinases in stem cells, development, and human developmental disorders

Human developmental disorders encompass a wide range of debilitating physical conditions and intellectual disabilities. Perturbation of protein kinase signalling underlies the development of some of these disorders. For example, disrupted SRPK signalling is associated with intellectual disabilities, and the gene dosage of DYRKs can dictate the pathology of disorders including Down's syndrome. Here, we review the emerging roles of the CMGC kinase families SRPK, CLK, DYRK, and sub-family HIPK during embryonic development and in developmental disorders. In particular, SRPK, CLK, and DYRK kinase families have key roles in developmental signalling and stem cell regulation, and can co-ordinate neuronal development and function. Genetic studies in model organisms reveal critical phenotypes including embryonic lethality, sterility, musculoskeletal errors, and most notably, altered neurological behaviours arising from defects of the neuroectoderm and altered neuronal signalling. Further unpicking the mechanisms of specific kinases using human stem cell models of neuronal differentiation and function will improve our understanding of human developmental disorders and may provide avenues for therapeutic strategies.

Tolerized Microglia Protect Neurons Against Endotoxin-Induced TNF-α Production via an LBP-Dependent Intracellular p38 MAPK Signaling Pathway

The development of microglial endotoxin tolerance (ET) is a critical event in protecting neurons against excessive immune responses when microglia are administered two consecutive lipopolysaccharide (LPS) challenges. However, the intrinsic mechanisms of microglia shape ET programs and protect neurons remain unclear. This study aimed to determine whether extracellular autocrine cascades or intracellular signaling pathways are involved in ET microglia-mediated tumor necrosis factor-alpha (TNF-α) reduction and neuroprotection. Neuron-glia cultures composed of astroglia, neurons, and microglia were performed in different conditions: with or without serum or LPS-binding proteins (LBP), along with an induction approach of ET. Enzyme-linked immunosorbent assay results revealed that LPS induced TNF-α tolerance of microglia in an LBP-dependent manner. Furthermore, we determined whether the early pro-inflammatory cytokines induced by LPS might contribute to the development of microglial ET. Our data showed that the neutralization of TNF-α using an anti-TNF-α antibody had no change in the TNF-α tolerance of microglia during the ET challenge. Furthermore, pre-incubation of TNF-α, interleukin-1 beta, and prostaglandin E2 failed to induce any TNF-α tolerance in microglia after LPS treatment. Moreover, using three specific chemical inhibitors that respectively blocked the activities of the mitogen-activated protein kinases (MAPKs) namely p38, c-Jun N-terminal kinase and extracellular signal-related kinases revealed that inhibition of p38 MAPK by SB203580 disrupted the tolerated microglia-mediated TNF-α reduction and neuroprotection. In summary, our findings demonstrated that the LPS pre-treatment immediately programmed the microglial ET to prevent endotoxin-induced TNF-α production and neuronal damage through the intracellular p38 MAPK signaling pathway.

Regulation of ERK2 activity by dynamic S-acylation

Extracellular signal-regulated kinases (ERK1/2) are key effector proteins of the mitogen-activated protein kinase pathway, choreographing essential processes of cellular physiology. Here, we discover that ERK1/2 are subject to S-acylation, a reversible lipid modification of cysteine residues, at C271/C254. The levels of ERK1/2 S-acylation are modulated by epidermal growth factor (EGF) signaling, mirroring its phosphorylation dynamics, and acylation-deficient ERK2 displays altered phosphorylation patterns. We show that ERK1/2 S-acylation is mediated by "writer" protein acyl transferases (PATs) and "eraser" acyl protein thioesterases (APTs) and that chemical inhibition of either lipid addition or removal alters ERK1/2's EGF-triggered transcriptional program. Finally, in a mouse model of metabolic syndrome, we find that ERK1/2 lipidation levels correlate with alterations in ERK1/2 lipidation writer/eraser expression, solidifying a link between ERK1/2 activity, ERK1/2 lipidation, and organismal health. This study describes how lipidation regulates ERK1/2 and offers insight into the role of dynamic S-acylation in cell signaling more broadly.

Molecular basis for cellular retinoic acid-binding protein 1 in modulating CaMKII activation

Introduction: Cellular retinoic acid (RA)-binding protein 1 (CRABP1) is a highly conserved protein comprised of an anti-parallel, beta-barrel, and a helix-turn-helix segment outside this barrel. Functionally, CRABP1 is thought to bind and sequester cytosolic RA. Recently, CRABP1 has been established as a major mediator of rapid, non-genomic activity of RA in the cytosol, referred to as "non-canonical" activity. Previously, we have reported that CRABP1 interacts with and dampens the activation of calcium-calmodulin (Ca2+-CaM)-dependent kinase 2 (CaMKII), a major effector of Ca2+ signaling. Through biophysical, molecular, and cellular assays, we, herein, elucidate the molecular and structural mechanisms underlying the action of CRABP1 in dampening CaMKII activation. Results: We identify an interaction surface on CRABP1 for CaMKII binding, located on the beta-sheet surface of the barrel, and an allosteric region within the helix segment outside the barrel, where both are important for interacting with CaMKII. Molecular studies reveal that CRABP1 preferentially associates with the inactive form of CaMKII, thereby dampening CaMKII activation. Alanine mutagenesis of residues implicated in the CaMKII interaction results in either a loss of this preference or a shift of CRABP1 from associating with the inactive CaMKII to associating with the active CaMKII, which corresponds to changes in CRABP1's effect in modulating CaMKII activation. Conclusions: This is the first study to elucidate the molecular and structural basis for CRABP1's function in modulating CaMKII activation. These results further shed insights into CRABP1's functional involvement in multiple signaling pathways, as well as its extremely high sequence conservation across species and over evolution.

Reactive Oxygen Species-Dependent Activation of EGFR/Akt/p38 Mitogen-Activated Protein Kinase and JNK1/2/FoxO1 and AP-1 Pathways in Human Pulmonary Alveolar Epithelial Cells Leads to Up-Regulation of COX-2/PGE2 Induced by Silica Nanoparticles

The risk of lung exposure to silica nanoparticles (SiNPs) and related lung inflammatory injury is increasing with the wide application of SiNPs in a variety of industries. A growing body of research has revealed that cyclooxygenase (COX)-2/prostaglandin E2 (PGE2) up-regulated by SiNP toxicity has a role during pulmonary inflammation. The detailed mechanisms underlying SiNP-induced COX-2 expression and PGE2 synthesis remain unknown. The present study aims to dissect the molecular components involved in COX-2/PGE2 up-regulated by SiNPs in human pulmonary alveolar epithelial cells (HPAEpiCs) which are one of the major targets while SiNPs are inhaled. In the present study, we demonstrated that SiNPs induced COX-2 expression and PGE2 release, which were inhibited by pretreatment with a reactive oxygen species (ROS) scavenger (edaravone) or the inhibitors of proline-rich tyrosine kinase 2 (Pyk2, PF-431396), epidermal growth factor receptor (EGFR, AG1478), phosphatidylinositol 3-kinase (PI3K, LY294002), protein kinase B (Akt, Akt inhibitor VIII), p38 mitogen-activated protein kinase (MAPK) (p38 MAPK inhibitor VIII), c-Jun N-terminal kinases (JNK)1/2 (SP600125), Forkhead Box O1 (FoxO1, AS1842856), and activator protein 1 (AP-1, Tanshinone IIA). In addition, we also found that SiNPs induced ROS-dependent Pyk2, EGFR, Akt, p38 MAPK, and JNK1/2 activation in these cells. These signaling pathways induced by SiNPs could further cause c-Jun and FoxO1 activation and translocation from the cytosol to the nucleus. AP-1 and FoxO1 activation could increase COX-2 and PGE2 levels induced by SiNPs. Finally, the COX-2/PGE2 axis might promote the inflammatory responses in HPAEpiCs. In conclusion, we suggested that SiNPs induced COX-2 expression accompanied by PGE2 synthesis mediated via ROS/Pyk2/EGFR/PI3K/Akt/p38 MAPK- and JNK1/2-dependent FoxO1 and AP-1 activation in HPAEpiCs.

The potential role of miRNAs and regulation of their expression in the development of mare endometrial fibrosis

Mare endometrial fibrosis (endometrosis), is one of the main causes of equine infertility. Despite the high prevalence, both ethology, pathogenesis and the nature of its progression remain poorly understood. Recent studies have shown that microRNAs (miRNAs) are important regulators in multiple cellular processes and functions under physiological and pathological circumstances. In this article, we reported changes in miRNA expression at different stages of endometrosis and the effect of transforming growth factor (TGF)-β1 on the expression of the most dysregulated miRNAs. We identified 1, 26, and 5 differentially expressed miRNAs (DEmiRs), in categories IIA (mild fibrosis), IIB (moderate fibrosis), and III (severe fibrosis) groups compared to category I (no fibrosis) endometria group, respectively (Padjusted < 0.05, log2FC ≥ 1.0/log2FC ≤  - 1.0). This study indicated the potential involvement of miRNAs in the regulation of the process associated to the development and progression of endometrosis. The functional enrichment analysis revealed, that DEmiRs target genes involved in the mitogen-activated protein kinases, Hippo, and phosphoinositide-3-kinase (PI3K)-Akt signalling pathways, focal adhesion, and extracellular matrix-receptor interaction. Moreover, we demonstrated that the most potent profibrotic cytokine-TGF-β1-downregulated novel-eca-miR-42 (P < 0.05) expression in fibroblasts derived from endometria at early-stage endometrosis (category IIA).

Sensitivity and Frequency Response of Biochemical Cascades

Signal transduction from a cell's surface to cytoplasmic and nuclear targets takes place through a complex network of interconnected pathways. Phosphorylation cycles are common components of many pathways and may take the form of a multi-layered cascade of cycles or incorporate species with multiple phosphorylation sites that effectively create a sequence of cycles with increasing states of phosphorylation. This work focuses on the frequency response and sensitivity of such systems, two properties that have not been thoroughly examined. Starting with a singularly phosphorylated single-cycle system, we compare the sensitivity to perturbation at steady-state across a range of input signal strengths. This is followed by a frequency response analysis focusing on the gain and associated bandwidth. Next, we consider a two-layer cascade of single phosphorylation cycles and focus on how the two cycles interact to produce various effects on the bandwidth and damping properties. Then we consider the (ultra)sensitivity of a doubly phosphorylated system, where we describe in detail first-order ultrasensitivity, a unique property of these systems, which can be blended with zero-order ultrasensitivity to create systems with relatively constant gain over a range of signal input. Finally, we give an in-depth analysis of the sensitivity of an n-phosphorylated system.

The Neuroprotective Effects of Flavonoid Fisetin against Corticosterone-Induced Cell Death through Modulation of ERK, p38, and PI3K/Akt/FOXO3a-Dependent Pathways in PC12 Cells

The overactive hypothalamic-pituitary-adrenal (HPA) axis is believed to trigger the overproduction of corticosterone, leading to neurotoxicity in the brain. Fisetin is a flavonoid commonly found in fruits and vegetables. It has been suggested to possess various biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects. This study aims to explore the potential neuroprotective properties of fisetin against corticosterone-induced cell death and its underlying molecular mechanism in PC12 cells. Our results indicate that fisetin, at concentrations ranging from 5 to 40 μM, significantly protected PC12 cells against corticosterone-induced cell death. Fisetin effectively reduced the corticosterone-mediated generation of reactive oxygen species (ROS) in PC12 cells. Fisetin treatments also showed potential in inhibiting the corticosterone-induced apoptosis of PC12 cells. Moreover, inhibitors targeting MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK, and phosphatidylinositol 3-kinase (PI3K) were found to significantly block the increase in cell viability induced by fisetin in corticosterone-treated cells. Consistently, fisetin enhanced the phosphorylation levels of ERK, p38, Akt, and c-AMP response element-binding protein (CREB) in PC12 cells. Additionally, it was found that the diminished levels of p-CREB and p-ERK by corticosterone can be restored by fisetin treatment. Furthermore, the investigation of crosstalk between ERK and CREB revealed that p-CREB activation by fisetin occurred through the ERK-independent pathway. Moreover, we demonstrated that fisetin effectively counteracted the corticosterone-induced nuclear accumulation of FOXO3a, an apoptosis-triggering transcription factor, and concurrently promoted FOXO3a phosphorylation and its subsequent cytoplasmic localization through the PI3K/Akt pathway. In conclusion, our findings indicate that fisetin exerts its neuroprotective effect against corticosterone-induced cell death by modulating ERK, p38, and the PI3K/Akt/FOXO3a-dependent pathways in PC12 cells. Fisetin emerges as a promising phytochemical for neuroprotection.

Insampaedok-San Extract Exerts an Immune-Enhancing Effect through NF-κB p65 Pathway Activation

Insampaedok-san (IS) has traditionally been prescribed as a medication for cold-related symptoms in Northeast Asia, including Korea and China. In this study, we focused on elucidating the molecular mechanism underlying the immunomodulatory activity of IS water extract (ISE) in macrophages. ISE significantly enhanced the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) by increasing the expression of inducible NO synthase and cyclooxygenase-2 (COX-2) in a dose-dependent manner. ISE, which consists of many herbs, contains a large number of active compounds whose pharmacological targets and mechanisms are complicated. Therefore, network pharmacology analysis was used to predict the potential key components, targets, and mechanisms of ISE as immunomodulators. Subsequently, the network pharmacology results were validated experimentally. Seven key components were identified through HPLC-QTOF-MS. As predicted by the network pharmacology analysis, ISE increased the mRNA expression of Tnf and Il6. Furthermore, ISE increased the phosphorylation, nuclear translocation, and transcriptional activity of the p65 subunit of the nuclear factor-κB (NF-κB) signaling pathway. In contrast, rapamycin, an NF-κB inhibitor, suppressed the ISE-induced mRNA expression of Tnf and Il6. In conclusion, ISE is an immune activator that can elevate the production of NO, PGE2, and proinflammatory cytokines mediated by NF-κB signaling.

The effect of hormones insulin and glucagon on ubiquitin modifications elucidated by proteomics in liver cells

AIMS

Insulin action is intertwined with changing levels of glucose and counter-regulatory hormone glucagon. While insulin lowers blood sugar level, glucagon raises it by promoting the breakdown of the stored glycogen in liver and releases glucose into the bloodstream. The hormones insulin and glucagon are key in the pathogenesis of type 2 diabetes (T2D). Insulin resistance is a primary predisposing factor for diabetes. Phosphorylation of insulin signaling molecules is altered in the insulin-resistant state. However, ubiquitin (Ub) modifications in insulin-resistant state are relatively understudied. To dissect the underlying mechanisms, we performed a proteomics study on hepatoma cells to study the regulation of ubiquitination by insulin and glucagon.

MATERIALS AND METHODS

We performed western blotting, immunoprecipitations, and affinity pull down using tandem Ub binding entities (TUBE) reagents on hepatoma cells treated with insulin or glucagon. Next, we performed MS/MS analysis on Ub-linkage specific affinity pull down samples. Gene ontology analysis and protein-protein interaction network analysis was performed using DAVID GO and STRING db, respectively.

KEY FINDINGS

The ubiquitination pattern of total Ub, K48-linked Ub, and K63-linked Ub was altered with the treatment of hormones insulin and glucagon. Ubiquitination in immunoprecipitated samples showed enrichment with total Ub and K48-linked Ub but not with K63-linked Ub. Ubiquitination by treatment with hormones mainly enriched key signaling pathways MAPK, Akt, oxidative stress etc. SIGNIFICANCE: Our study identified key altered proteins and signal transduction pathways which aids in understanding the mechanisms of hormonal action on ubiquitination and identify new therapeutic targets for T2D.

Revisiting p38 Mitogen-Activated Protein Kinases (MAPK) in Inflammatory Arthritis: A Narrative of the Emergence of MAPK-Activated Protein Kinase Inhibitors (MK2i)

The p38 mitogen-activated protein kinase (p38-MAPK) is a crucial signaling pathway closely involved in several physiological and cellular functions, including cell cycle, apoptosis, gene expression, and responses to stress stimuli. It also plays a central role in inflammation and immunity. Owing to disparate p38-MAPK functions, it has thus far formed an elusive drug target with failed clinical trials in inflammatory diseases due to challenges including hepatotoxicity, cardiac toxicity, lack of efficacy, and tachyphylaxis, which is a brief initial improvement with rapid disease rebound. To overcome these limitations, downstream antagonism of the p38 pathway with a MAPK-activated protein kinase (MAPKAPK, also known as MK2) blockade has demonstrated the potential to abrogate inflammation without the prior recognized toxicities. Such MK2 inhibition (MK2i) is associated with robust suppression of key pro-inflammatory cytokines, including TNFα and IL-6 and others in experimental systems and in vitro. Considering this recent evidence regarding MK2i in inflammatory arthritis, we revisit the p38-MAPK pathway and discuss the literature encompassing the challenges of p38 inhibitors with a focus on this pathway. We then highlight how novel MK2i strategies, although encouraging in the pre-clinical arena, may either show evidence for efficacy or the lack of efficacy in emergent human trials data from different disease settings.

Treatment of Alzheimer's Disease: Beyond Symptomatic Therapies

In an ever-increasing aged world, Alzheimer's disease (AD) represents the first cause of dementia and one of the first chronic diseases in elderly people. With 55 million people affected, the WHO considers AD to be a disease with public priority. Unfortunately, there are no final cures for this pathology. Treatment strategies are aimed to mitigate symptoms, i.e., acetylcholinesterase inhibitors (AChEI) and the N-Methyl-D-aspartate (NMDA) antagonist Memantine. At present, the best approaches for managing the disease seem to combine pharmacological and non-pharmacological therapies to stimulate cognitive reserve. Over the last twenty years, a number of drugs have been discovered acting on the well-established biological hallmarks of AD, deposition of β-amyloid aggregates and accumulation of hyperphosphorylated tau protein in cells. Although previous efforts disappointed expectations, a new era in treating AD has been working its way recently. The Food and Drug Administration (FDA) gave conditional approval of the first disease-modifying therapy (DMT) for the treatment of AD, aducanumab, a monoclonal antibody (mAb) designed against Aβ plaques and oligomers in 2021, and in January 2023, the FDA granted accelerated approval for a second monoclonal antibody, Lecanemab. This review describes ongoing clinical trials with DMTs and non-pharmacological therapies. We will also present a future scenario based on new biomarkers that can detect AD in preclinical or prodromal stages, identify people at risk of developing AD, and allow an early and curative treatment.

Asarinin attenuates bleomycin-induced pulmonary fibrosis by activating PPARγ

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that lacks effective treatment modalities. Once patients are diagnosed with IPF, their median survival is approximately 3-5 years. PPARγ is an important target for the prevention and treatment of pulmonary fibrosis. Asarinin is a lignan compound that can be extracted from food plant Asarum heterotropoides. In this study, we investigated the therapeutic effects of asarinin in a pulmonary fibrosis model constructed using bleomycin in mice and explored the underlying mechanisms. Intraperitoneal administration of asarinin to mice with pulmonary fibrosis showed that asarinin effectively attenuated pulmonary fibrosis, and this effect was significantly inhibited by the PPARγ inhibitor GW9662. Asarinin inhibited TGF-β1-induced fibroblast-to-myofibroblast transition in vitro, while GW9662 and PPARγ gene silencing significantly inhibited this effect. In addition, asarinin inhibited not only the canonical Smad pathway of TGF-β but also the non-canonical AKT and MAPK pathways by activating PPARγ. Our study demonstrates that asarinin can be used as a therapeutic agent for pulmonary fibrosis, and that PPARγ is its key target.

Functional Distinctions of Endometrial Cancer-Associated Mutations in the Fibroblast Growth Factor Receptor 2 Gene

Functional analysis of somatic mutations in tumorigenesis facilitates the development and optimization of personalized therapy for cancer patients. The fibroblast growth factor receptor 2 (FGFR2) gene is frequently mutated in endometrial cancer (EC), but the functional implications of FGFR2 mutations in cancer development remain largely unexplored. In this study, we introduced a reliable and readily deployable screening method to investigate the effects of FGFR2 mutations. We demonstrated that distinct mutations in FGFR2 can lead to differential downstream consequences, specifically affecting a disintegrin- and metalloprotease 17 (ADAM17)-dependent shedding of the epidermal growth factor receptor (EGFR) ligand heparin-binding EGF-like growth factor (HB-EGF) and phosphorylation of mitogen-activated protein kinases (MAPKs). Furthermore, we showed that the distribution of mutations within the FGFR2 gene can influence their oncogenic effects. Together, these findings provide important insights into the complex nature of FGFR2 mutations and their potential implications for EC. By unraveling the distinct effects of different mutations, our study contributes to the identification of personalized treatment strategies for patients with FGFR2-mutated cancers. This knowledge has the potential to guide the development of targeted therapies that specifically address the underlying molecular alterations associated with FGFR2 mutations, ultimately improving patient outcomes in EC and potentially other cancer types characterized by FGFR2 mutations.

Irisin as an agent for protecting against osteoporosis: A review of the current mechanisms and pathways

BACKGROUND

Osteoporosis is recognized as a skeletal disorder characterized by diminished bone tissue quality and density. Regular physical exercise is widely acknowledged to preserve and enhance bone health, but the detailed molecular mechanisms involved remain unclear. Irisin, a factor derived from muscle during exercise, influences bone and muscle. Since its discovery in 2012, irisin has been found to promote bone growth and reduce bone resorption, establishing a tangible link between muscle exertion and bone health. Consequently, the mechanism by which irisin prevents osteoporosis have attracted significant scientific interest.

AIM OF THE REVIEW

This study aims to elucidate the multifaceted relationship between exercise, irisin, and bone health. Focusing on irisin, a muscle-derived factor released during exercise, we seek to understand its role in promoting bone growth and inhibiting resorption. Through a review of current research article on irisin in osteoporosis, Our review provides a deep dive into existing research on influence of irisin in osteoporosis, exploring its interaction with pivotal signaling pathways and its impact on various cell death mechanisms and inflammation. We aim to uncover the molecular underpinnings of how irisin, secreted during exercise, can serve as a therapeutic strategy for osteoporosis.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

Irisin, secreted during exercise, plays a vital role in bridging muscle function to bone health. It not only promotes bone growth but also inhibits bone resorption. Specifically, Irisin fosters osteoblast proliferation, differentiation, and mineralization predominantly through the ERK, p38, and AMPK signaling pathways. Concurrently, it regulates osteoclast differentiation and maturation via the JNK, Wnt/β-catenin and RANKL/RANK/OPG signaling pathways. This review further delves into the profound significance of irisin in osteoporosis and its involvement in diverse cellular death mechanisms, including apoptosis, autophagy, ferroptosis, and pyroptosis.

Reactive Oxygen Species and H. pylori Infection: A Comprehensive Review of Their Roles in Gastric Cancer Development

Gastric cancer (GC) is the fifth most common cancer worldwide and makes up a significant component of the global cancer burden. Helicobacter pylori (H. pylori) is the most influential risk factor for GC, with the International Agency for Research on Cancer classifying it as a Class I carcinogen for GC. H. pylori has been shown to persist in stomach acid for decades, causing damage to the stomach's mucosal lining, altering gastric hormone release patterns, and potentially altering gastric function. Epidemiological studies have shown that eliminating H. pylori reduces metachronous cancer. Evidence shows that various molecular alterations are present in gastric cancer and precancerous lesions associated with an H. pylori infection. However, although H. pylori can cause oxidative stress-induced gastric cancer, with antioxidants potentially being a treatment for GC, the exact mechanism underlying GC etiology is not fully understood. This review provides an overview of recent research exploring the pathophysiology of H. pylori-induced oxidative stress that can cause cancer and the antioxidant supplements that can reduce or even eliminate GC occurrence.

Glucose Transporter-2 Regulation of Male versus Female Hypothalamic Astrocyte MAPK Expression and Activation: Impact of Glucose

The plasma membrane glucose transporter (GLUT)-2 is unique among GLUT family proteins in that it also functions as a glucose sensor. GLUT2 imposes sex-dimorphic control of hypothalamic astrocyte glucose storage and catabolism by unknown mechanisms. Mitogen-activated protein kinase (MAPK) signaling cascades operate within stress-sensitive signal transduction pathways. Current research employed an established primary astrocyte culture model and gene knockdown tools to investigate whether one or more of the three primary MAP kinase families are regulated by GLUT2. GLUT2 gene knockdown caused opposing adjustments in total ERK1/2 proteins in glucose-supplied male versus female astrocytes, augmenting or reducing the mean phosphorylated/total protein ratio for 44 and 42 kDa variants in these sexes. Glucose deprivation amplified this ratio for both ERK1/2 variants, albeit by a larger magnitude in male; GLUT2 siRNA exacerbated this stimulatory response in males only. Phosphorylated/total p38 MAPK protein ratios were up-regulated by GLUT2 knockdown in male, but not female astrocytes. Glucose-deprived astrocytes exhibited no change (male) or reduction (female) in this ratio after GLUT2 gene silencing. GLUT2 siRNA increased the phosphorylated/total protein ratio for 54 and 46 kDa SAPK/JNK proteins in each sex when glucose was present. However, glucose withdrawal suppressed (male) or amplified (female) these ratios, while GLUT2 knockdown attenuated these inverse responses. Results show that GLUT2 inhibits ERK1/2, p38, and SAPK/JNK MAPK activity in male, but differentially stimulates and inhibits activity of these signaling pathways in female hypothalamic astrocytes. Glucoprivation induces divergent adjustments in astrocyte p38 MAPK and SAPK/JNK activities. The findings demonstrate a stimulatory role for GLUT2 in p38 MAPK activation in glucose-starved female astrocytes, but can act as either an inhibitor or inducer of SAPK/JNK activation in glucose-deprived male versus female glial cells, respectively.

P38 kinase in gastrointestinal cancers

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen‑activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

Inductive effect of SORT1 on odontoblastic differentiation of human dental pulp-derived stem cells

This study investigated the expression of sortilin 1 (SORT1) in cultured human dental pulp-derived stem cells (hDPSCs) and its role in their odontoblastic differentiation. Permanent teeth were extracted from five patients, and the dental pulp was harvested for explant culture. Fluorescence-activated cell sorting was used to analyze the outgrowth of adherent cells and cells that had migrated from the tissue margin. SORT1 expression was detected in hDPSCs simultaneously expressing the mesenchymal stem cell markers CD44 and CD90. The odontoblastic differentiation potential of SORT1-positive hDPSCs was examined via staining for alkaline phosphatase (ALP), an early odontoblastic differentiation marker. ALP staining was more intense in SORT1-positive than in SORT1-negative hDPSCs. Consistently, the expression of mRNA encoding SORT1 and p75NTR, a binding partner of SORT1, increased in SORT1-positive hDPSCs during odontoblastic differentiation. In addition, pro-nerve growth factor (NGF), a ligand for SORT1-p75NTR co-receptor, promoted ALP expression in SORT1-positive hDPSCs, and the interaction between SORT1 and p75NTR was detected using a coimmunoprecipitation assay. The function of SORT1 in odontoblastic differentiation was examined via RNA interference using shRNA targeting SORT1. ALP staining intensity in SORT1/shRNA-transfected cells was markedly lower than in control/shRNA-transfected cells. SORT1 knockdown decreased JUN phosphorylation and recruitment of phosphorylated JUN to the ALP promoter. Collectively, these results indicate that SORT1 is involved in the odontoblastic differentiation of hDPSCs through the JUN N-terminal kinases (JNK)/JUN signaling pathway and that the binding of SORT1 and p75NTR plays an important role in this process.

Association of single-nucleotide polymorphisms in dual specificity phosphatase 8 and insulin-like growth factor 2 genes with inosine-5'-monophosphate, inosine, and hypoxanthine contents in chickens

OBJECTIVE

This study aimed to identify the single-nucleotide polymorphisms (SNPs) in the dual-specificity phosphatase 8 (DUSP8) and insulin-like growth factor 2 (IGF2) genes and to explore their effects on inosine-5'-monophosphate (IMP), inosine, and hypoxanthine contents in Korean native chicken -red-brown line (KNC-R Line).

METHODS

A total sample of 284 (males, n = 127; females n = 157) and 230 (males, n = 106; females, n = 124) aged of 10 weeks old KNC-R line was used for genotyping of DUSP8 and IGF2 genes, respectively. One SNP (rs313443014 C>T) in DUSP8 gene and two SNPs (rs315806609A/G and rs313810945T/C) in IGF2 gene were used for genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and KASP methods, respectively. The Two-way analysis of variance of the R program was used to associate DUSP8 and IGF2 genotypes with nucleotide contents in KNC-R chickens.

RESULTS

The DUSP8 (rs313443014 C>T) was polymorphic in KNC-R line and showed three genotypes: CC, CT, and TT. The IGF2 gene (rs315806609A/G and rs313810945T/C) was also polymorphic and had three genotypes per SNP, including GG, AG, and AA for the SNP rs315806609A/G and genotypes: CC, CT, and TT for the SNP rs313810945T/C. Association resulted into a strong significant association (p<0.01) with IMP, inosine, and hypoxanthine. Moreover, the significant effect of sex (p<0.05) on nucleotide content was also observed.

CONCLUSION

The SNPs in the DUSP8 and IGF2 genes might be used as genetic markers in the selection and production of chickens with highly flavored meat.

Metabolic protein kinase signalling in neuroblastoma

BACKGROUND

Neuroblastoma is a paediatric malignancy of incredibly complex aetiology. Oncogenic protein kinase signalling in neuroblastoma has conventionally focussed on transduction through the well-characterised PI3K/Akt and MAPK pathways, in which the latter has been implicated in treatment resistance. The discovery of the receptor tyrosine kinase ALK as a target of genetic alterations in cases of familial and sporadic neuroblastoma, was a breakthrough in the understanding of the complex genetic heterogeneity of neuroblastoma. However, despite progress in the development of small-molecule inhibitors of ALK, treatment resistance frequently arises and appears to be a feature of the disease. Moreover, since the identification of ALK, several additional protein kinases, including the PIM and Aurora kinases, have emerged not only as drivers of the disease phenotype, but also as promising druggable targets. This is particularly the case for Aurora-A, given its intimate engagement with MYCN, a driver oncogene of aggressive neuroblastoma previously considered 'undruggable.'

SCOPE OF REVIEW

Aided by significant advances in structural biology and a broader understanding of the mechanisms of protein kinase function and regulation, we comprehensively outline the role of protein kinase signalling, emphasising ALK, PIM and Aurora in neuroblastoma, their respective metabolic outputs, and broader implications for targeted therapies.

MAJOR CONCLUSIONS

Despite massively divergent regulatory mechanisms, ALK, PIM and Aurora kinases all obtain significant roles in cellular glycolytic and mitochondrial metabolism and neuroblastoma progression, and in several instances are implicated in treatment resistance. While metabolism of neuroblastoma tends to display hallmarks of the glycolytic "Warburg effect," aggressive, in particular MYCN-amplified tumours, retain functional mitochondrial metabolism, allowing for survival and proliferation under nutrient stress. Future strategies employing specific kinase inhibitors as part of the treatment regimen should consider combinatorial attempts at interfering with tumour metabolism, either through metabolic pathway inhibitors, or by dietary means, with a view to abolish metabolic flexibility that endows cancerous cells with a survival advantage.

Transgenic overexpression of heat shock protein (HSP83) enhances protein kinase A activity, disrupts GP63 surface protease expression and alters promastigote morphology in Leishmania amazonensis

Leishmania parasites undergo morphological changes during their infectious life cycle, including developmental transitions within the sandfly vector, culminating in metacyclic stages that are pre-adapted for infection. Upon entering vertebrate host phagocytes, Leishmania differentiate into intracellular amastigotes, the form that is ultimately transmitted back to the vector to complete the life cycle. Although environmental conditions that induce these cellular transitions are well-established, molecular mechanisms governing Leishmania morphologic differentiation in response to these cues remain largely uncharacterized. Previous studies indicate a key role for HSP83 in both promastigote metacyclogenesis and amastigote differentiation. To further elucidate HSP83 functions in the Leishmania lifecycle, we examined the biological impact of experimentally elevating HSP83 gene expression in Leishmania. Significantly, HSP83 overexpression was associated with altered metacyclic morphology, increased protein kinase A (PKA) activity and decreased expression of the Leishmania major surface protease, GP63. Corroborating these findings, overexpression of the L. amazonensis PKA catalytic subunit resulted in a largely similar phenotype. Our findings demonstrate for the first time in Leishmania, a functional link between HSP83 and PKA in the control of Leishmania gene expression, replication and morphogenesis.

Phosphorylated MAPK11 promotes the progression of clear cell renal cell carcinoma by maintaining RUNX2 protein abundance

Previous studies have demonstrated that mitogen-activated protein kinase 11 (MAPK11) functions as an important point of integration in signalling transduction pathways and controlling endocellular processes, including viability of cells, differentiation, proliferation and apoptosis, through the sequence phosphorylation of the substrate protein Ser/Thr kinase protein cascade. Though MAPK 11 plays an important role in various tumours, especially in the invasive and metastatic processes, its expression and molecular mechanism in clear cell renal cell carcinoma (ccRCC) remain unclear. Runt-associated transcription factor 2 (RUNX2), a main transcription factor for osteoblast differentiation and chondrocyte maturation, has high expression in a number of tumours. In this study, the mRNA and protein levels of targeted genes in ccRCC tissues and adjacent tissues are analysed using the Cancer Genome Atlas (TCGA) database and western blotting. The ccRCC cell proliferation was measured with colony formation and EdU assay, and cell migration was examined through transwell assay. The interactive behaviour between proteins was detected with immunoprecipitation. Half-life period of RUNX2 protein was measured with cycloheximide chase assay. The results of the study indicated overexpression of MAPK11 and RUNX2 in ccRCC tissues and cell lines. MAPK11 and RUNX2 promoted the ccRCC cell proliferation and migration. Additionally, physical interaction took place between RUNX2 and P-MAPK11, which functioned to sustain the stability of RUNX2 protein. The high expression of RUNX2 could neutralize the functional degradation in MAPK11. And the outcomes of the study suggest that the P-MAPK11/RUNX2 axis may be used as a potential therapeutic target of ccRCC.

Severe fever with thrombocytopenia syndrome virus induces platelet activation and apoptosis via a reactive oxygen species-dependent pathway

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by the SFTS virus (SFTSV) and with a high fatality rate. Thrombocytopenia is a major clinical manifestation observed in SFTS patients, but the underlying mechanism remains largely unclear. Here, we explored the effects of SFTSV infection on platelet function in vivo in severely infected SFTSV IFNar-/- mice and on mouse and human platelet function in vitro. Results showed that SFTSV-induced platelet clearance acceleration may be the main reason for thrombocytopenia. SFTSV-potentiated platelet activation and apoptosis were also observed in infected mice. Further investigation showed that SFTSV infection induced platelet reactive oxygen species (ROS) production and mitochondrial dysfunction. In vitro experiments revealed that administration of SFTSV or SFTSV glycoprotein (Gn) increased activation, apoptosis, ROS production, and mitochondrial dysfunction in separated mouse platelets, which could be effectively ameliorated by the application of antioxidants (NAC (N-acetyl-l-cysteine), SKQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) and resveratrol). In vivo experiments showed that the antioxidants partially rescued SFTSV infection-induced thrombocytopenia by improving excessive ROS production and mitochondrial dysfunction and down-regulating platelet apoptosis and activation. Furthermore, while SFTSV and Gn directly potentiated human platelet activation, it was completely abolished by antioxidants. This study revealed that SFTSV and Gn can directly trigger platelet activation and apoptosis in an ROS-MAPK-dependent manner, which may contribute to thrombocytopenia and hemorrhage during infection, but can be abolished by antioxidants.

JNK Cascade-Induced Apoptosis-A Unique Role in GqPCR Signaling

The response of cells to extracellular signals is mediated by a variety of intracellular signaling pathways that determine stimulus-dependent cell fates. One such pathway is the cJun-N-terminal Kinase (JNK) cascade, which is mainly involved in stress-related processes. The cascade transmits its signals via a sequential activation of protein kinases, organized into three to five tiers. Proper regulation is essential for securing a proper cell fate after stimulation, and the mechanisms that regulate this cascade may involve the following: (1) Activatory or inhibitory phosphorylations, which induce or abolish signal transmission. (2) Regulatory dephosphorylation by various phosphatases. (3) Scaffold proteins that bring distinct components of the cascade in close proximity to each other. (4) Dynamic change of subcellular localization of the cascade's components. (5) Degradation of some of the components. In this review, we cover these regulatory mechanisms and emphasize the mechanism by which the JNK cascade transmits apoptotic signals. We also describe the newly discovered PP2A switch, which is an important mechanism for JNK activation that induces apoptosis downstream of the Gq protein coupled receptors. Since the JNK cascade is involved in many cellular processes that determine cell fate, addressing its regulatory mechanisms might reveal new ways to treat JNK-dependent pathologies.

Transcriptome Responses to Different Environments in Intertidal Zones in the Peanut Worm Sipunculus nudus

The peanut worm (Sipunculus nudus) is an important intertidal species worldwide. Species living in the same aquaculture area might suffer different environmental impacts. To increase knowledge of the molecular mechanisms underlying the response to environmental fluctuations, we performed a transcriptome analysis of S. nudus from different intertidal zones using a combination of the SMRT platform and the Illumina sequencing platform. (1) A total of 105,259 unigenes were assembled, and 23,063 unigenes were perfectly annotated. The results of the PacBio Iso-Seq and IIIumina RNA-Seq enriched the genetic database of S. nudus. (2) A total of 830 DEGs were detected in S. nudus from the different groups. In particular, 33 DEGs had differential expression in the top nine KEGG pathways related to pathogens, protein synthesis, and cellular immune response and signaling. The results indicate that S. nudus from different zones experience different environmental stresses. (3) Several DEGs (HSPA1, NFKBIA, eEF1A, etc.) in pathways related to pathogens (influenza A, legionellosis, measles, and toxoplasmosis) had higher expression in groups M and L. HSPA1 was clearly enriched in most of the pathways, followed by NFKBIA. The results show that the peanut worms from the M and L tidal flats might have suffered more severe environmental conditions. (4) Some DEGs (MKP, MRAS, and HSPB1) were upregulated in peanut worms from the H tidal flat, and these DEGs were mainly involved in the MAPK signaling pathway. These results indicate that the MAPK pathway may play a vital role in the immune response of the peanut worm to the effects of different intertidal flats. This study provides a valuable starting point for further studies to elucidate the molecular basis of the response to different environmental stresses in S. nudus.

Dual-specificity protein phosphatase 6 (DUSP6) overexpression reduces amyloid load and improves memory deficits in male 5xFAD mice

Background

Dual specificity protein phosphatase 6 (DUSP6) was recently identified as a key hub gene in a causal network that regulates late-onset Alzheimer's disease. Importantly, decreased DUSP6 levels are correlated with an increased clinical dementia rating in human subjects, and DUSP6 levels are additionally decreased in the 5xFAD amyloidopathy mouse model.

Methods

AAV5-DUSP6 or AAV5-GFP (control) were stereotactically injected into the dorsal hippocampus (dHc) of female and male 5xFAD or wild type mice to overexpress DUSP6 or GFP. Spatial learning memory of these mice was assessed in the Barnes maze, after which hippocampal tissues were isolated for downstream analysis.

Results

Barnes maze testing indicated that DUSP6 overexpression in the dHc of 5xFAD mice improved memory deficits and was associated with reduced amyloid plaque load, Aß 1-40 and Aß 1-42 levels, and amyloid precursor protein processing enzyme BACE1, in male but not in female mice. Microglial activation and microgliosis, which are increased in 5xFAD mice, were significantly reduced by dHc DUSP6 overexpression in both males and females. Transcriptomic profiling of female 5xFAD hippocampus revealed upregulated expression of genes involved in inflammatory and extracellular signal-regulated kinase (ERK) pathways, while dHc DUSP6 overexpression in female 5xFAD mice downregulated a subset of genes in these pathways. A limited number of differentially expressed genes (DEGs) (FDR<0.05) were identified in male mice; gene ontology analysis of DEGs (p<0.05) identified a greater number of synaptic pathways that were regulated by DUSP6 overexpression in male compared to female 5xFAD. Notably, the msh homeobox 3 gene, Msx3 , previously shown to regulate microglial M1/M2 polarization and reduce neuroinflammation, was one of the most robustly upregulated genes in female and male wild type and 5xFAD mice overexpressing DUSP6.

Conclusions

In summary, our data indicate that DUSP6 overexpression in dHc reduced amyloid deposition and memory deficits in male but not female 5xFAD mice, whereas reduced neuroinflammation and microglial activation were observed in both males and females. The sex-dependent regulation of synaptic pathways by DUSP6 overexpression, however, correlated with the improvement of spatial memory deficits in male but not female 5xFAD.

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.

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.

Monoclonal antibodies binding to different epitopes of CD20 differentially sensitize DLBCL to different classes of chemotherapy

Introduction

Rituximab (R), an anti-CD20 monoclonal antibody (mAb) and the world's first approved antibody for oncology patients, was combined with the CHOP chemotherapy regimen and markedly improved the prognosis of all B- cell-derived lymphomas, the most common hematological malignancy worldwide. However, there is a 35% disease recurrence with no advancement in the first-line treatment since R was combined with the archetypal CHOP chemotherapy regimen nearly 30 years ago. There is evidence that R synergizes with chemotherapy, but the pharmacological interactions between R and CHOP or between newer anti-CD20 mAbs and CHOP remain largely unexplored.

Methods

We used in vitro models to score pharmacological interactions between R and CHOP across various lymphoma cell lines. We compared these pharmacological interactions to ofatumumab, a second-generation anti-CD20 mAb, and CHOP. Lastly, we used RNA-sequencing to characterize the transcriptional profiles induced by these two antibodies and potential molecular pathways that mediate their different effects.

Results

We discovered vast heterogeneity in the pharmacological interactions between R and CHOP in a way not predicted by the current clinical classification. We then discovered that R and ofatumumab differentially synergize with the cytotoxic and cytostatic capabilities of CHOP in separate distinct subsets of B-cell lymphoma cell lines, thereby expanding favorable immunochemotherapy interactions across a greater range of cell lines beyond those induced by R-CHOP. Lastly, we discovered these two mAbs differentially modulate genes enriched in the JNK and p38 MAPK family, which regulates apoptosis and proliferation.

Discussion

Our findings were completely unexpected because these mAbs were long considered to be biological and clinical equivalents but, in practice, may perform better than the other in a patient-specific manner. This finding may have immediate clinical significance because both immunochemotherapy combinations are already FDA-approved with no difference in toxicity across phase I, II, and III clinical trials. Therefore, this finding could inform a new precision medicine strategy to provide additional therapeutic benefit to patients with B-cell lymphoma using immunochemotherapy combinations that already meet the clinical standard of care.

Fibrotic extracellular vesicles contribute to mechanical ventilation-induced pulmonary fibrosis development by activating lung fibroblasts via JNK signalling pathway: an experimental study

Recent research has revealed that mechanical ventilation (MV) could initiate ventilator-induced lung injury along with the initiation of the process of pulmonary fibrosis (PF), leading to MV-induced PF (MVPF). However, the underlying mechanism remains unclear. This study aimed to explore the role of MV-induced extracellular vesicles (MV-EVs) and the c-Jun N-terminal kinase (JNK) signalling pathway in the pathogenesis of MVPF in vivo and in vitro. The process of MV is accompanied by the secretion of MV-EVs, which could induce lung fibroblast activation. Furthermore, single-cell RNA-sequencing analysis revealed that the JNK pathway in lung fibroblasts was activated after MV initiation. Inhibiting the JNK pathway could both restrain MV-EV-induced lung fibroblast activation in vitro or reduce the severity of MVPF in vivo. In conclusion, this study demonstrated that MV-EVs contribute to MVPF progression by activating lung fibroblasts via the JNK signalling pathway and that inhibiting the secretion of EV and the activation of the JNK signalling pathway is a promising strategy for treating MVPF.

Psychological distress influences lung cancer: Advances and perspectives on the immune system and immunotherapy

Lung cancer has the highest incidence rate and mortality worldwide. Moreover, multiple factors may cause heterogeneity in the efficacy of immunotherapy for lung cancer, and preclinical studies have gradually uncovered the promotive effects of psychological distress (PD) on tumor hallmarks. Therefore, treatment targeted at PD may be a vital factor in adjusting and improving immunotherapy for lung cancer. Here, by focusing on the central nervous system, as well as stress-related crucial neurotransmitters and hormones, we highlight the effects of PD on the lung immune system, the lung tumor microenvironment (TME) and immunotherapy, which brings a practicable means and psychosocial perspective to lung cancer treatment.

Consolidating the association of biallelic MAPKAPK5 pathogenic variants with a distinct syndromic neurodevelopmental disorder

BACKGROUND

MAPK-activated protein kinase 5 (MAPKAPK5) is an essential enzyme for diverse cellular processes. Dysregulation of the pathways regulated by MAPKAPK enzymes can lead to the development of variable diseases. Recently, homozygous loss-of-function variants in MAPKAPK5 were reported in four patients from three families presenting with a recognisable neurodevelopmental disorder, so-called 'neurocardiofaciodigital' syndrome.

OBJECTIVE AND METHODS

In order to improve characterisation of the clinical features associated with biallelic MAPKAPK5 variants, we employed a genotype-first approach combined with reverse deep-phenotyping of three affected individuals.

RESULTS

In the present study, we identified biallelic loss-of-function and missense MAPKAPK5 variants in three unrelated individuals from consanguineous families. All affected individuals exhibited a syndromic neurodevelopmental disorder characterised by severe global developmental delay, intellectual disability, characteristic facial morphology, brachycephaly, digital anomalies, hair and nail defects and neuroradiological findings, including cerebellar hypoplasia and hypomyelination, as well as variable vision and hearing impairment. Additional features include failure to thrive, hypotonia, microcephaly and genitourinary anomalies without any reported congenital heart disease.

CONCLUSION

In this study, we consolidate the causality of loss of MAPKAPK5 function and further delineate the molecular and phenotypic spectrum associated with this new ultra-rare neurodevelopmental syndrome.

Transcriptome Analysis of the Inhibitory Effects of 20(S)-Protopanaxadiol on NCI-H1299 Non-Small Cell Lung Cancer Cells

Lung cancer seriously threatens human health. To explore the molecular mechanism of 20(S)-Protopanaxadiol (PPD) on human non-small cell lung cancer cells, we investigated the transcriptional profile of PPD-treated NCI-H1299 cells. Cell proliferation, cell cycle, and apoptosis were detected using cell counting kit-8 and flow cytometry, respectively. Differentially expressed genes (DEGs) between PPD-treated and untreated cells were determined using RNA sequencing and bioinformatic analysis. Protein phosphorylation was detected using Western blotting. Data of mRNA expression profiles of lung cancer were from The Cancer Genome Atlas (TCGA) and analyzed using R software version 4.3.1. PPD showed an inhibitory effect on the proliferation of NCI-H1299 cells and induced apoptosis. There were 938 upregulated genes and 466 downregulated genes in PPD-treated cells, and DEGs were primarily enriched in the MAPK signaling pathway. The detection of phosphorylation revealed that the phosphorylation of ERK and p38 MAPK was significantly reduced in PPD-treated cells. Further comparison of PPD-regulated DEGs with clinical data of lung adenocarcinoma demonstrated that most downregulated genes in tumor tissues were upregulated in PPD-treated cells or vice versa. Two PPD-downregulated genes HSPA2 and EFNA2 were associated with patients' overall survival. Therefore, PPD could inhibit NCI-H1299 cells by affecting gene expression and regulating ERK and p38 MAPK pathways.

Epigallocatechin-3-Gallate, an Active Green Tea Component to Support Anti-VEGFA Therapy in Wet Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a largely incurable disease and an emerging problem in aging societies. It occurs in two forms, dry and wet (exudative, neovascular), which may cause legal blindness and sight loss. Currently, there is not any effective treatment for dry AMD. Meanwhile, repeated intravitreal injections with antibodies effective against vascular endothelial growth factor A (VEGFA) slow down wet AMD progression but are not free from complications. (-)-Epigallocatechin-3-gallate (EGCG) is an active compound of green tea, which exerts many beneficial effects in the retinal pigment epithelium and the neural retina. It has been reported to downregulate the VEGFA gene by suppressing its activators. The inhibition of mitogen-activated protein kinases 1 and 3 (MAPK1 and MAPK3) may lie behind the antiangiogenic action of EGCG mediated by VEGFA. EGCG exerts protective effects against UV-induced damage to retinal cells and improves dysfunctional autophagy. EGCG may also interact with the mechanistic target rapamycin (MTOR) and unc-51-like autophagy activating kinase (ULK1) to modulate the interplay between autophagy and apoptosis. Several other studies report beneficial effects of EGCG on the retina that may be related to wet AMD. Therefore, controlled clinical trials are needed to verify whether diet supplementation with EGCG or green tea consumption may improve the results of anti-VEGFA therapy in wet AMD.

CMGC Kinases in Health and Cancer

CMGC kinases, encompassing cyclin-dependent kinases (CDKs), mitogen-activated protein kinases (MAPKs), glycogen synthase kinases (GSKs), and CDC-like kinases (CLKs), play pivotal roles in cellular signaling pathways, including cell cycle regulation, proliferation, differentiation, apoptosis, and gene expression regulation. The dysregulation and aberrant activation of these kinases have been implicated in cancer development and progression, making them attractive therapeutic targets. In recent years, kinase inhibitors targeting CMGC kinases, such as CDK4/6 inhibitors and BRAF/MEK inhibitors, have demonstrated clinical success in treating specific cancer types. However, challenges remain, including resistance to kinase inhibitors, off-target effects, and the need for better patient stratification. This review provides a comprehensive overview of the importance of CMGC kinases in cancer biology, their involvement in cellular signaling pathways, protein-protein interactions, and the current state of kinase inhibitors targeting these kinases. Furthermore, we discuss the challenges and future perspectives in targeting CMGC kinases for cancer therapy, including potential strategies to overcome resistance, the development of more selective inhibitors, and novel therapeutic approaches, such as targeting protein-protein interactions, exploiting synthetic lethality, and the evolution of omics in the study of the human kinome. As our understanding of the molecular mechanisms and protein-protein interactions involving CMGC kinases expands, so too will the opportunities for the development of more selective and effective therapeutic strategies for cancer treatment.

Nitric oxide-induced ribosome collision activates ribosomal surveillance mechanisms

Impairment of protein translation can cause stalling and collision of ribosomes and is a signal for the activation of ribosomal surveillance and rescue pathways. Despite clear evidence that ribosome collision occurs stochastically at a cellular and organismal level, physiologically relevant sources of such aberrations are poorly understood. Here we show that a burst of the cellular signaling molecule nitric oxide (NO) reduces translational activity and causes ribosome collision in human cell lines. This is accompanied by activation of the ribotoxic stress response, resulting in ZAKα-mediated activation of p38 and JNK kinases. In addition, NO production is associated with ZNF598-mediated ubiquitination of the ribosomal protein RPS10 and GCN2-mediated activation of the integrated stress response, which are well-described responses to the collision of ribosomes. In sum, our work implicates a novel role of NO as an inducer of ribosome collision and activation of ribosomal surveillance mechanisms in human cells.

Asiaticoside Mitigates Alzheimer's Disease Pathology by Attenuating Inflammation and Enhancing Synaptic Function

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder, hallmarked by the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles. Due to the uncertainty of the pathogenesis of AD, strategies aimed at suppressing neuroinflammation and fostering synaptic repair are eagerly sought. Asiaticoside (AS), a natural triterpenoid derivative derived from Centella asiatica, is known for its anti-inflammatory, antioxidant, and wound-healing properties; however, its neuroprotective function in AD remains unclear. Our current study reveals that AS, when administered (40 mg/kg) in vivo, can mitigate cognitive dysfunction and attenuate neuroinflammation by inhibiting the activation of microglia and proinflammatory factors in Aβ1-42-induced AD mice. Further mechanistic investigation suggests that AS may ameliorate cognitive impairment by inhibiting the activation of the p38 MAPK pathway and promoting synaptic repair. Our findings propose that AS could be a promising candidate for AD treatment, offering neuroinflammation inhibition and enhancement of synaptic function.

Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay

Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production. This results in an innate immune response that can eliminate the bacterial pathogen. However, enteric bacterial pathogens evolved sophisticated mechanisms that interfere with such a response by delivering virulent proteins, termed effectors, and toxins into the host cells. These proteins act in numerous ways to inactivate or activate critical components of the MAPK signaling cascades and innate immunity. The consequence of such activities could lead to successful bacterial colonization, dissemination, and pathogenicity. This article will review enteric bacterial pathogens' strategies to modulate MAPKs and host responses. It will also discuss findings attempting to develop anti-microbial treatments by targeting MAPKs.

Myocardial fibrosis in rheumatic heart disease: emerging concepts and clinical implications

Rheumatic heart disease (RHD) remains a significant cardiovascular burden in the world even though it is no longer common in affluent countries. Centuries of history surrounding this disease provide us with a thorough understanding of its pathophysiology. Infections in the throat, skin, or mucosa are the gateway for Group A Streptococcus (GAS) to penetrate our immune system. A significant inflammatory response to the heart is caused by an immunologic cascade triggered by GAS antigen cross-reactivity. This exaggerated immune response is primarily responsible for cardiac dysfunction. Recurrent inflammatory processes damage all layers of the heart, including the endocardium, myocardium, and pericardium. A vicious immunological cycle involving inflammatory mediators, angiotensin II, and TGF-β promotes extracellular matrix remodeling, resulting in myocardial fibrosis. Myocardial fibrosis appears to be a prevalent occurrence in patients with RHD. The presence of myocardial fibrosis, which causes left ventricular dysfunction in RHD, might be utilized to determine options for treatment and might also be used to predict the outcome of interventions in patients with RHD. This emerging concept of myocardial fibrosis needs to be explored comprehensively in order to be optimally utilized in the treatment of RHD.

Polysaccharides-based nanocarriers enhance the anti-inflammatory effect of curcumin

Curcumin (CUR) has been discovered to have many biological activities, including anti-inflammatory, anti-cancer, anti-oxygenation, anti-human immunodeficiency virus, anti-microbial and exhibits a good effect on the prevention and treatment of many diseases. However, the limited properties of CUR, including the poor solubility, bioavailability and instability caused by enzymes, light, metal irons, and oxygen, have compelled researchers to turn their attention to drug carrier application to overcome these drawbacks. Encapsulation may provide potential protective effects to the embedding materials and/or have a synergistic effect with them. Therefore, nanocarriers, especially polysaccharides-based nanocarriers, have been developed in many studies to enhance the anti-inflammatory capacity of CUR. Consequently, it's critical to review current advancements in the encapsulation of CUR using polysaccharides-based nanocarriers, as well as further study the potential mechanisms of action where polysaccharides-based CUR nanoparticles (the complex nanoparticles/Nano CUR-delivery systems) exhibit their anti-inflammatory effects. This work suggests that polysaccharides-based nanocarriers will be a thriving field in the treatment of inflammation and inflammation-related diseases.

COVID-19 of differing severity: from bulk to single-cell expression data analysis

Coronavirus disease 2019 (COVID-19) is raging worldwide and causes an immense disease burden. Despite this, the biomarkers and targeting drugs of COVID-19 of differing severity remain largely unknown. Based on the GSE164805 dataset, we identified modules most critical for mild COVID-19 (mCOVID-19) and severe COVID-19 (sCOVID-19) through WGCNA, respectively. We subsequently constructed a protein-protein interaction network, and detected 16 hub genes for mCOVID-19 and 10 hub genes for sCOVID-19, followed by the prediction of upstream transcription factors (TFs) and kinases. The enrichment analysis then showed downregulation of TNFA signaling via NFKB for mCOVID-19, as well as downregulation of MYC targets V1 for sCOVID-19. Infiltration degrees of many immune cells, such as macrophages, were also sharply different between mCOVID-19 and sCOVID-19 samples. Predicted protein targeting drugs with the highest scores nearly all belong to naturally derived or synthetic glucocorticoids. For the two single-cell RNA-seq datasets, we explored the expression distribution of hub genes for mCOVID-19/sCOVID-19 in each cell type. The expression levels of PRKCA, MCM5, TYMS, RBBP4, BCL6, FLOT1, KDM6B, and TLR2 were found to be cell-type-specific. Furthermore, the expression levels of 10 hub genes for mCOVID-19 were significantly upregulated in PBMCs between eight healthy controls and eight mCOVID-19 patients at our institution. Collectively, we detected critical modules, pathways, TFs, kinases, immune cells, targeting drugs, hub genes, and their expression distributions in different cell types that may involve the pathogenesis of COVID-19 of differing severity, which may propel earlier diagnosis and more effective treatment of this intractable disease in the future.

JNK signaling during IL-3-mediated differentiation contributes to the c-kit-potentiated allergic inflammatory capacity of mast cells

Mast cells are leukocytes that mediate various aspects of immunity and drive allergic hypersensitivity pathologies. Mast cells differentiate from hematopoietic progenitor cells in a manner that is largely IL-3 dependent. However, molecular mechanisms, including the signaling pathways that control this process, have yet to be thoroughly investigated. Here, we examine the role of the ubiquitous and critical mitogen-activated protein kinase signaling pathway due to its position downstream of the IL-3 receptor. Hematopoietic progenitor cells were harvested from the bone marrow of C57BL/6 mice and differentiated to bone marrow-derived mast cells in the presence of IL-3 and mitogen-activated protein kinase inhibitors. Inhibition of the JNK node of the mitogen-activated protein kinase pathway induced the most comprehensive changes to the mature mast cell phenotype. Bone marrow-derived mast cells differentiated during impaired JNK signaling expressed impaired c-kit levels on the mast cell surface, first detected at week 3 of differentiation. Following 1 wk of inhibitor withdrawal and subsequent stimulation of IgE-sensitized FcεRI receptors with allergen (TNP-BSA) and c-kit receptors with stem cell factor, JNK-inhibited bone marrow-derived mast cells exhibited impediments in early-phase mediator release through degranulation (80% of control), as well as late-phase secretion of CCL1, CCL2, CCL3, TNF, and IL-6. Experiments with dual stimulation conditions (TNP-BSA + stem cell factor or TNP-BSA alone) showed that impediments in mediator secretion were found to be mechanistically linked to reduced c-kit surface levels. This study is the first to implicate JNK activity in IL-3-mediated mast cell differentiation and also identifies development as a critical and functionally determinative period.

Epigenetic modification in diabetic kidney disease

Diabetic kidney disease (DKD) is a common microangiopathy in diabetic patients and the main cause of death in diabetic patients. The main manifestations of DKD are proteinuria and decreased renal filtration capacity. The glomerular filtration rate and urinary albumin level are two of the most important hallmarks of the progression of DKD. The classical treatment of DKD is controlling blood glucose and blood pressure. However, the commonly used clinical therapeutic strategies and the existing biomarkers only partially slow the progression of DKD and roughly predict disease progression. Therefore, novel therapeutic methods, targets and biomarkers are urgently needed to meet clinical requirements. In recent years, increasing attention has been given to the role of epigenetic modification in the pathogenesis of DKD. Epigenetic variation mainly includes DNA methylation, histone modification and changes in the noncoding RNA expression profile, which are deeply involved in DKD-related inflammation, oxidative stress, hemodynamics, and the activation of abnormal signaling pathways. Since DKD is reversible at certain disease stages, it is valuable to identify abnormal epigenetic modifications as early diagnosis and treatment targets to prevent the progression of end-stage renal disease (ESRD). Because the current understanding of the epigenetic mechanism of DKD is not comprehensive, the purpose of this review is to summarize the role of epigenetic modification in the occurrence and development of DKD and evaluate the value of epigenetic therapies in DKD.

Serum proteome profiling of naturally acquired Babesia rossi infection in dogs

Babesiosis is a disease of significant medically and veterinary importance with worldwide distribution. It is caused by intra-erythrocyte protozoal parasites, with Babesia rossi causing the most severe clinical signs of all the large Babesia parasites infecting dogs. The disease can be clinically classified into uncomplicated and complicated forms with a wide range of clinical presentations from a mild, subclinical illness to complicated forms and death. The aim of this study was to assess serum proteomic profiles from dogs with babesiosis and healthy dogs using a label-based proteomics approach. Altogether 32 dogs naturally infected with B. rossi (subdivided into 18 uncomplicated cases and 14 complicated cases of babesiosis) and 20 healthy dogs were included. There were 78 proteins with significantly different abundances between the three groups of dogs. Elucidation of proteins and pathways involved in canine babesiosis caused by B. rossi have revealed key differences associated with haemostasis, innate immune system, lipid metabolism and inflammation. Shotgun proteomic profiling allowed identification of potential serum biomarkers for differentiation of disease severity in canine babesiosis caused by B. rossi. These findings may be applicable to the study of host-parasite interactions and the development of novel therapeutic targets.

Genome-wide identification and immune response analysis of mitogen-activated protein kinase cascades in tea geometrid, Ectropis grisescens Warren (Geometridae, Lepidoptera)

BACKGROUND

Tea geometrid Ectropis grisescens (Geometridae: Lepidoptera), is one of the most destructive defoliators in tea plantations in China. The MAPK cascade is known to be an evolutionarily conserved signaling module, acting as pivotal cores of host-pathogen interactions. Although the chromosome-level reference genome of E. grisescens was published, the whole MAPK cascade gene family has not been fully identified yet, especially the expression patterns of MAPK cascade gene family members upon an ecological biopesticide, Metarhizium anisopliae, remains to be understood.

RESULTS

In this study, we have identified 19 MAPK cascade gene family members in E. grisescens, including 5 MAPKs, 4 MAP2Ks, 8 MAP3Ks, and 2 MAP4Ks. The molecular evolution characteristics of the whole Eg-MAPK cascade gene family, including gene structures, protein structural organization, chromosomal localization, orthologs construction and gene duplication, were systematically investigated. Our results showed that the members of Eg-MAPK cascade gene family were unevenly distributed in 13 chromosomes, and the clustered members in each group shared similar structures of the genes and proteins. Gene expression data revealed that MAPK cascade genes were expressed in all four developmental stages of E. grisescens and were fairly and evenly distributed in four different larva tissues. Importantly, most of the MAPK cascade genes were induced or constitutively expressed upon M. anisopliae infection.

CONCLUSIONS

In summary, the present study was one of few studies on MAPK cascade gene in E. grisescens. The characterization and expression profiles of Eg-MAPK cascades genes might help develop new ecofriendly biological insecticides to protect tea trees.

Structural insights into regulation of the PEAK3 pseudokinase scaffold by 14-3-3

PEAK pseudokinases are molecular scaffolds which dimerize to regulate cell migration, morphology, and proliferation, as well as cancer progression. The mechanistic role dimerization plays in PEAK scaffolding remains unclear, as there are no structures of PEAKs in complex with their interactors. Here, we report the cryo-EM structure of dimeric PEAK3 in complex with an endogenous 14-3-3 heterodimer. Our structure reveals an asymmetric binding mode between PEAK3 and 14-3-3 stabilized by one pseudokinase domain and the SHED domain of the PEAK3 dimer. The binding interface contains a canonical phosphosite-dependent primary interaction and a unique secondary interaction not observed in previous structures of 14-3-3/client complexes. Additionally, we show that PKD regulates PEAK3/14-3-3 binding, which when prevented leads to PEAK3 nuclear enrichment and distinct protein-protein interactions. Altogether, our data demonstrate that PEAK3 dimerization forms an unusual secondary interface for 14-3-3 binding, facilitating 14-3-3 regulation of PEAK3 localization and interactome diversity.

Tetrandrine inhibits the proliferation of mesangial cells induced by enzymatically deglycosylated human IgA1 via IgA receptor/MAPK/NF-κB signaling pathway

Objective: Despite the use of renin-angiotensin system blockade and immunosuppressive drugs, including corticosteroids, the current treatment regimens for Immunoglobulins A nephropathy (IgAN) are severely limited. The proliferation of mesangial cell and deposition of deglycosylated human IgA1 immune complex are the most common pathologic features of IgAN. We examined the tetrandrine potential of suppressing the proliferation of mesangial cells and explored its underlying mechanisms with a focus on IgA receptor/MAPK/NF-κB signaling pathway. Methods: Standard human IgA (native IgA) were enzymatically desialylated (deS IgA) or further degalactosylated (deS/deGal IgA) using neuraminidase and β-galactosidase. Rat glomerular mesangial cells (HBZY-1) and human renal mesangial cells (HRMC) stimulated by IgA were used to observe the suppressive effect of tetrandrine. The MTT assay was used to detect the cell viability. The protein expression of IgA receptor/MAPK/NF-κB signaling pathway was examined by Western blot. Cell cycle analysis was measured by flow cytometer. Results: Native IgA and deS IgA showed limited stimulation effect on both HBZY-1 cells and HRMCs, whereas deS/deGal IgA significantly stimulated the proliferation of both HBZY-1 cells and HRMCs (p < 0.05). Compared with non-stimulation of deS/deGal IgA, 1-3 μM of tetrandrine had stronger inhibitory effect on the proliferation of HBZY-1 cells and HRMCs with the stimulation of deS/deGal IgA (p < 0.05), suggesting that tetrandrine possibly inhibited the proliferation of mesangial cells induced by deglycosylated human IgA1 specifically. Molecular mechanism study revealed that tetrandrine decreased the expression of IgA1 receptor, CD71 and β4GALT1, and inhibited the activation of MAPK/NF-κB significantly (p < 0.05). Moreover, these inhibitory effect of tetrandrine caused cell cycle arrest and stopped the cell growth in the S phase companied with the upregulating of cyclin A2 and downregulating of cyclin D1. Conclusion: Taken together, tetrandrine inhibited the proliferation of mesangial cells induced by enzymatically deglycosylated human IgA1 via IgA receptor/MAPK/NF-κB signaling pathway. Based on these potential molecular mechanisms, tetrandrine would be an appealing therapeutic option for IgAN.

The reduced SCFA-producing gut microbes are involved in the inflammatory activation in Kawasaki disease

Kawasaki disease (KD), an acute febrile systemic vasculitis in children, has become the leading cause of acquired heart disease in developed countries. Recently, the altered gut microbiota was found in KD patients during the acute phase. However, little is known about its characteristics and role in the pathogenesis of KD. In our study, an altered gut microbiota composition featured by the reduction in SCFAs-producing bacteria was demonstrated in the KD mouse model. Next, probiotic Clostridium butyricum (C. butyricum) and antibiotic cocktails were respectively employed to modulate gut microbiota. The use of C. butyricum significantly increased the abundance of SCFAs-producing bacteria and attenuated the coronary lesions with reduced inflammatory markers IL-1β and IL-6, but antibiotics depleting gut bacteria oppositely deteriorated the inflammation response. The gut leakage induced by dysbiosis to deteriorate the host's inflammation was confirmed by the decreased intestinal barrier proteins Claudin-1, Jam-1, Occludin, and ZO-1, and increased plasma D-lactate level in KD mice. Mechanistically, SCFAs, the major beneficial metabolites of gut microbes to maintain the intestinal barrier integrity and inhibit inflammation, was also found decreased, especially butyrate, acetate and propionate, in KD mice by gas chromatography-mass spectrometry (GC-MS). Moreover, the reduced expression of SCFAs transporters, monocarboxylate transporter 1 (MCT-1) and sodium-dependent monocarboxylate transporter 1 (SMCT-1), was also shown in KD mice by western blot and RT-qPCR analyses. As expected, the decrease of fecal SCFAs production and barrier dysfunction were improved by oral C. butyricum treatment but was deteriorated by antibiotics. In vitro, butyrate, not acetate or propionate, increased the expression of phosphatase MKP-1 to dephosphorylate activated JNK, ERK1/2 and p38 MAPK against excessive inflammation in RAW264.7 macrophages. It suggests a new insight into probiotics and their metabolites supplements to treat KD.

The ideal reporting of RAS testing in colorectal adenocarcinoma: a pathologists' perspective

RAS gene mutational status represents an imperative predictive biomarker to be tested in the clinical management of metastatic colorectal adenocarcinoma. Even if it is one of the most studied biomarkers in the era of precision medicine, several pre-analytical and analytical factors may still impasse an adequate reporting of RAS status in clinical practice, with significant therapeutic consequences. Thus, pathologists should be aware on the main topics related to this molecular evaluation: (i) adopt diagnostic limit of detections adequate to avoid the interference of sub-clonal cancer cell populations; (ii) choose the most adequate diagnostic strategy according to the available sample and its qualification for molecular testing; (iii) provide all the information regarding the mutation detected, since many RAS mutation-specific targeted therapeutic approaches are in development and will enter into routine clinical practice. In this review, we give a comprehensive description of the current scenario about RAS gene mutational testing in the clinic focusing on the pathologist's role in patient selection for targeted therapies.