Extracellular Signal-Regulated Kinase: A Regulator of Cell Growth, Inflammation, Chondrocyte and Bone Cell Receptor-Mediated Gene Expression

Unraveling the pathogenesis of myelosuppression and therapeutic potential of natural products

BACKGROUND

Myelosuppression is a serious and common complication of radiotherapy and chemotherapy in cancer patients and is characterized by a reduction of peripheral blood cells. This condition not only compromises the efficacy of treatment but also increases the risk of patient death. Natural products are emerging as promising adjuvant therapies due to their antioxidant properties, ability to modulate immune responses, and capacity to stimulate haematopoietic stem cell proliferation. These therapies demonstrate significant potential in ameliorating myelosuppression.

METHODS

A systematic review of the literature was performed utilizing the search terms "natural products," "traditional Chinese medicine," and "myelosuppression" across prominent databases, including Google Scholar, PubMed, and Web of Science. All pertinent literature was meticulously analysed and summarized. The objective of this study was to perform a pertinent analysis to elucidate the mechanisms underlying myelosuppression and to categorize and synthesize information on natural products and traditional Chinese medicines employed for the therapeutic management of myelosuppression.

RESULTS

Myelosuppression resulting from drug and radiation exposure, viral infections, and exosomes is characterized by multiple underlying mechanisms involving immune factors, target genes, and the activation of diverse signalling pathways, including the (TGF-β)/Smad pathway. Recently, traditional Chinese medicine monomers and compounds, including more than twenty natural products, such as Astragalus and Angelica, have shown promising potential as therapeutics for ameliorating myelosuppression. These natural products exert their effects by modulating haematopoietic stem cells, immune factors, and critical signalling pathways.

CONCLUSIONS

Understanding the various mechanisms of myelosuppression facilitates the exploration of natural product therapies and biological target identification for evaluating herbal medicine efficacy. This study aimed to establish a foundation for the clinical application of natural products and provide methodologies and technical support for exploring additional treatments for myelosuppression.

AI-based prediction of protein-ligand binding affinity and discovery of potential natural product inhibitors against ERK2

Determination of protein-ligand binding affinity (PLA) is a key technological tool in hit discovery and lead optimization, which is critical to the drug development process. PLA can be determined directly by experimental methods, but it is time-consuming and costly. In recent years, deep learning has been widely applied to PLA prediction, the key of which lies in the comprehensive and accurate representation of proteins and ligands. In this study, we proposed a multi-modal deep learning model based on the early fusion strategy, called DeepLIP, to improve PLA prediction by integrating multi-level information, and further used it for virtual screening of extracellular signal-regulated protein kinase 2 (ERK2), an ideal target for cancer treatment. Experimental results from model evaluation showed that DeepLIP achieved superior performance compared to state-of-the-art methods on the widely used benchmark dataset. In addition, by combining previously developed machine learning models and molecular dynamics simulation, we screened three novel hits from a drug-like natural product library. These compounds not only had favorable physicochemical properties, but also bound stably to the target protein. We believe they have the potential to serve as starting molecules for the development of ERK2 inhibitors.

GPS2 ameliorates cigarette smoking-induced pulmonary vascular remodeling by modulating the ras-Raf-ERK axis

BACKGROUND

Mitogen-activated protein kinase (MAPK)signaling-mediated smoking-associated pulmonary vascular remodeling (PVR) plays an important role in the pathogenesis of group 3 pulmonary hypertension (PH). And G protein pathway suppressor 2 (GPS2) could suppress G-protein signaling such as Ras and MAPK, but its role in cigarette smoking -induced PVR (CS-PVR) is unclear.

METHODS

An in vivo model of smoke-exposed rats was constructed to assess the role of GPS2 in smoking-induced PH and PVR. In vitro, the effects of GPS2 overexpression and silencing on the function of human pulmonary arterial smooth cells (HPASMCs) and the underlying mechanisms were explored.

RESULTS

GPS2 expression was downregulated in rat pulmonary arteries (PAs) and HPASMCs after CS exposure. More importantly, CS-exposed rats with GPS2 overexpression had lower right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and wall thickness (WT%) than those without. And enhanced proliferation and migration of HPASMCs induced by cigarette smoking extract (CSE) can be evidently inhibited by overexpressed GPS2. Besides, GPS2siRNA significantly enhanced the proliferation, and migration of HPASMCs as well as activated Ras and Raf/ERK signaling, while these effects were inhibited by zoledronic acid (ZOL). In addition, GPS2 promoter methylation level in rat PAs and HPASMCs was increased after CS exposure, and 5-aza-2-deoxycytidine (5-aza) inhibited CSE-induced GPS2 hypermethylation and downregulation in vitro.

CONCLUSIONS

GPS2 overexpression could improve the CS-PVR, suggesting that GPS2 might serve as a novel therapeutic target for PH-COPD in the future.

Bone and Extracellular Signal-Related Kinase 5 (ERK5)

Bones are vital for anchoring muscles, tendons, and ligaments, serving as a fundamental element of the human skeletal structure. However, our understanding of bone development mechanisms and the maintenance of bone homeostasis is still limited. Extracellular signal-related kinase 5 (ERK5), a recently identified member of the mitogen-activated protein kinase (MAPK) family, plays a critical role in the pathogenesis and progression of various diseases, especially neoplasms. Recent studies have highlighted ERK5's significant role in both bone development and bone-associated pathologies. This review offers a detailed examination of the latest research on ERK5 in different tissues and diseases, with a particular focus on its implications for bone health. It also examines therapeutic strategies and future research avenues targeting ERK5.

Hexaconazole induces developmental toxicities via apoptosis, inflammation, and alterations of Akt and MAPK signaling cascades

Hexaconazole is a highly effective triazole fungicide that is frequently applied in various countries to elevate crop productivity. Given its long half-life and high water solubility, this fungicide is frequently detected in the environment, including water sources. Moreover, hexaconazole exerts hazardous effects on nontarget organisms. However, little is known about the toxic effects of hexaconazole on animal development. Thus, this study aimed to investigate the developmental toxicity of hexaconazole to zebrafish, a valuable animal model for toxicological studies, and elucidate the underlying mechanisms. Results showed that hexaconazole affected the viability and hatching rate of zebrafish at 96 h postfertilization. Hexaconazole-treated zebrafish showed phenotypic defects, such as reduced size of head and eyes and enlarged pericardiac edema. Moreover, hexaconazole induced apoptosis, DNA fragmentation, and inflammation in developing zebrafish. Various organ defects, including neurotoxicity, cardiovascular toxicity, and hepatotoxicity, were observed in transgenic zebrafish models olig2:dsRed, fli1:eGFP, and l-fabp:dsRed. Furthermore, hexaconazole treatment altered the Akt and MAPK signaling pathways, which possibly triggered the organ defects and other toxic mechanisms. This study demonstrated the developmental toxicity of hexaconazole to zebrafish and elucidated the underlying mechanisms.

Analysis of the effect of CCR7 on the microenvironment of mouse oral squamous cell carcinoma by single-cell RNA sequencing technology

BACKGROUND

Studies have shown that CCR7, an important inflammatory factor, can promote the proliferation and metastasis of oral squamous cell carcinoma (OSCC), but its role in the tumor microenvironment (TME) remains unclear. This paper explores the role of CCR7 in the TME of OSCC.

METHODS

In this work, we constructed CCR7 gene knockout mice and OSCC mouse models. Single-cell RNA sequencing (scRNA-seq) and bioinformatics were used to analyze the differences in the OSCC microenvironment between three CCR7 gene knockout mice (KO) and three wild-type mice (WT). Immunohistochemistry, immunofluorescence staining, and flow cytometry were used to analyze the expression of key genes in significantly different cell types between the KO and WT groups. An in vitro experiment was used to verify the effect of CCR7 on M2 macrophage polarization.

RESULTS

In the mouse OSCC models, the tumor growth rate in the KO group was significantly lower than that in the WT group. Eight main cell types (including tumor cells, fibroblasts, macrophages, granulocytes, T cells, endothelial cells, monocytes, and B cells) were identified by Seurat analysis. The scRNA-seq results showed that the proportion of tumor cells was lower, but the proportion of inflammatory cells was significantly higher in the KO group than in the WT group. CellPhoneDB analysis results indicated a strong interaction relationship between tumor cells and macrophages, T cells, fibroblasts, and endothelial cells. Functional enrichment results indicated that the expression level of the Dusp1 gene in the KO group was generally higher than that in the WT group in various cell types. Macrophage subclustering results indicated that the proportion of M2 macrophages in the KO group was lower than that in the WT group. In vitro experimental results showed that CCR7 can promote M2 macrophage polarization, thus promoting the proliferation, invasion and migration of OSCC cells.

CONCLUSIONS

CCR7 gene knockout can significantly inhibit the growth of mouse oral squamous cell carcinoma by promoting the polarization of M2 macrophages.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Rheumatoid arthritis: pathogenesis and therapeutic advances

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the unresolved synovial inflammation for tissues-destructive consequence, which remains one of significant causes of disability and labor loss, affecting about 0.2-1% global population. Although treatments with disease-modifying antirheumatic drugs (DMARDs) are effective to control inflammation and decrease bone destruction, the overall remission rates of RA still stay at a low level. Therefore, uncovering the pathogenesis of RA and expediting clinical transformation are imminently in need. Here, we summarize the immunological basis, inflammatory pathways, genetic and epigenetic alterations, and metabolic disorders in RA, with highlights on the abnormality of immune cells atlas, epigenetics, and immunometabolism. Besides an overview of first-line medications including conventional DMARDs, biologics, and small molecule agents, we discuss in depth promising targeted therapies under clinical or preclinical trials, especially epigenetic and metabolic regulators. Additionally, prospects on precision medicine based on synovial biopsy or RNA-sequencing and cell therapies of mesenchymal stem cells or chimeric antigen receptor T-cell are also looked forward. The advancements of pathogenesis and innovations of therapies in RA accelerates the progress of RA treatments.

Rheumatoid arthritis-recent advances in pathogenesis and the anti-inflammatory effect of plant-derived COX inhibitors

The majority of people with autoimmune disorders, including those with rheumatoid arthritis, osteoarthritis, and tendonitis report pain, stiffness, and inflammation as major contributors to their worse quality of life in terms of overall health. Of all the available treatment options, COX inhibitors are the ones that are utilized most frequently to ease the symptoms. Various signaling cascades have been reported to be involved in the pathogenesis of rheumatoid arthritis which includes JAK/STAT, MAPK, and NF-kB signaling pathways, and several allopathic inhibitors (tofacitinib and baricitinib) have been reported to target the components of these cascades and have received approval for RA treatment. However, the prolonged use of these COX inhibitors and other allopathic drugs can pose serious health challenges due to their significant side effects. Therefore, searching for a more effective and side effect-free treatment for rheumatoid arthritis has unveiled phytochemicals as both productive and promising. Their therapeutic ability helps develop potent and safe drugs targeting immune-inflammatory diseases including RA. Various scientific databases were used for searching articles such as NCBI, SpringerLink, BioMed Central, ResearchGate, Google Scholar, Scopus, Nature, Wiley Online Library, and ScienceDirect. This review lists various phytochemicals and discusses their potential molecular targets in RA treatment, as demonstrated by various in vitro, in vivo (pre-clinical), and clinical studies. Several pre-clinical and clinical studies suggest that various phytochemicals can be an alternative promising intervention for attenuating and managing inflammation-associated pathogenesis of rheumatoid arthritis.

The role of mechanically sensitive ion channel Piezo1 in bone remodeling

Piezo1 (2010) was identified as a mechanically activated cation channel capable of sensing various physical forces, such as tension, osmotic pressure, and shear force. Piezo1 mediates mechanosensory transduction in different organs and tissues, including its role in maintaining bone homeostasis. This review aimed to summarize the function and possible mechanism of Piezo1 in the mechanical receptor cells in bone tissue. We found that it is a potential therapeutic target for the treatment of bone diseases.

The Na/K-ATPase role as a signal transducer in lung inflammation

Acute respiratory distress syndrome (ARDS) is marked by damage to the capillary endothelium and alveolar epithelium following edema formation and cell infiltration. Currently, there are no effective treatments for severe ARDS. Pathologies such as sepsis, pneumonia, fat embolism, and severe trauma may cause ARDS with respiratory failure. The primary mechanism of edema clearance is the epithelial cells' Na/K-ATPase (NKA) activity. NKA is an enzyme that maintains the electrochemical gradient and cell homeostasis by transporting Na+ and K+ ions across the cell membrane. Direct injury on alveolar cells or changes in ion transport caused by infections decreases the NKA activity, loosening tight junctions in epithelial cells and causing edema formation. In addition, NKA acts as a receptor triggering signal transduction in response to the binding of cardiac glycosides. The ouabain (a cardiac glycoside) and oleic acid induce lung injury by targeting NKA. Besides enzymatic inhibition, the NKA triggers intracellular signal transduction, fostering proinflammatory cytokines production and contributing to lung injury. Herein, we reviewed and discussed the crucial role of NKA in edema clearance, lung injury, and intracellular signaling pathway activation leading to lung inflammation, thus putting the NKA as a protagonist in lung injury pathology.

Conformational diversity and protein-protein interfaces in drug repurposing in Ras signaling pathway

We focus on drug repurposing in the Ras signaling pathway, considering structural similarities of protein-protein interfaces. The interfaces formed by physically interacting proteins are found from PDB if available and via PRISM (PRotein Interaction by Structural Matching) otherwise. The structural coverage of these interactions has been increased from 21 to 92% using PRISM. Multiple conformations of each protein are used to include protein dynamics and diversity. Next, we find FDA-approved drugs bound to structurally similar protein-protein interfaces. The results suggest that HIV protease inhibitors tipranavir, indinavir, and saquinavir may bind to EGFR and ERBB3/HER3 interface. Tipranavir and indinavir may also bind to EGFR and ERBB2/HER2 interface. Additionally, a drug used in Alzheimer's disease can bind to RAF1 and BRAF interface. Hence, we propose a methodology to find drugs to be potentially used for cancer using a dataset of structurally similar protein-protein interface clusters rather than pockets in a systematic way.

Mechanistic target of rapamycin in regulating macrophage function in inflammatory cardiovascular diseases

The mechanistic target of rapamycin (mTOR) is evolutionarily conserved from yeast to humans and is one of the most fundamental pathways of living organisms. Since its discovery three decades ago, mTOR has been recognized as the center of nutrient sensing and growth, homeostasis, metabolism, life span, and aging. The role of dysregulated mTOR in common diseases, especially cancer, has been extensively studied and reported. Emerging evidence supports that mTOR critically regulates innate immune responses that govern the pathogenesis of various cardiovascular diseases. This review discusses the regulatory role of mTOR in macrophage functions in acute inflammation triggered by ischemia and in atherosclerotic cardiovascular disease (ASCVD) and heart failure with preserved ejection fraction (HFpEF), in which chronic inflammation plays critical roles. Specifically, we discuss the role of mTOR in trained immunity, immune senescence, and clonal hematopoiesis. In addition, this review includes a discussion on the architecture of mTOR, the function of its regulatory complexes, and the dual-arm signals required for mTOR activation to reflect the current knowledge state. We emphasize future research directions necessary to understand better the powerful pathway to take advantage of the mTOR inhibitors for innovative applications in patients with cardiovascular diseases associated with aging and inflammation.

Inhibition of microRNA-34c reduces detrusor ROCK2 expression and urinary bladder inflammation in experimental cystitis

Interstitial cystitis (IC), also called painful bladder syndrome (PBS), is 2 to 5 times more common in women than in men, yet its cause and pathogenesis remain unclear. In our study using the cyclophosphamide (CYP)-induced mouse model of cystitis, histological evaluation of the urinary bladder (UB) lamina propria (LP) showed immune cell infiltrations, indicating moderate to severe inflammation. In this study, we noticed a differential expression of a subset of microRNAs (miRs) in the UB cells (UBs) of CYP-induced cystitis as compared to the control. UB inflammatory scores and inflammatory signaling were also elevated in CYP-induced cystitis as compared to control. We identified eight UBs miRs that exhibited altered expression after CYP induction and are predicted to have a role in inflammation and smooth muscle function (miRs-34c-5p, -34b-3p, -212-3p, -449a-5p, -21a-3p, -376b-3p, -376b-5p and - 409-5p). Further analysis using ELISA for inflammatory markers and real-time PCR (RT-PCR) for differentially enriched miRs identified miR-34c as a potential target for the suppression of UB inflammation in cystitis. Blocking miR-34c by antagomir ex vivo reduced STAT3, TGF-β1, and VEGF expression in the UBs, which was induced during cystitis as compared to control. Interestingly, miR-34c inhibition also downregulated ROCK2 but elevated ROCK1 expression in bladder and detrusor cells. Thus, the present study shows that targeting miR-34c can mitigate the STAT3, TGF-β, and VEGF, inflammatory signaling in UB, and suppress ROCK2 expression in UBs to effectively suppress the inflammatory response in cystitis. This study highlights miR-34c as a potential biomarker and/or serves as the basis for new therapies for the treatment of cystitis.

IRE1α regulates the PTHrP-IHH feedback loop to orchestrate chondrocyte hypertrophy and cartilage mineralization

Cartilage development is controlled by the highly synergistic proliferation and differentiation of growth plate chondrocytes, in which the Indian hedgehog (IHH) and parathyroid hormone-related protein-parathyroid hormone-1 receptor (PTHrP-PTH1R) feedback loop is crucial. The inositol-requiring enzyme 1α/X-box-binding protein-1 spliced (IRE1α/XBP1s) branch of the unfolded protein response (UPR) is essential for normal cartilage development. However, the precise role of ER stress effector IRE1α, encoded by endoplasmic reticulum to nucleus signaling 1 (ERN1), in skeletal development remains unknown. Herein, we reported that loss of IRE1α accelerates chondrocyte hypertrophy and promotes endochondral bone growth. ERN1 acts as a negative regulator of chondrocyte proliferation and differentiation in postnatal growth plates. Its deficiency interrupted PTHrP/PTH1R and IHH homeostasis leading to impaired chondrocyte hypertrophy and differentiation. XBP1s, produced by p-IRE1α-mediated splicing, binds and up-regulates PTH1R and IHH, which coordinate cartilage development. Meanwhile, ER stress cannot be activated normally in ERN1-deficient chondrocytes. In conclusion, ERN1 deficiency accelerates chondrocyte hypertrophy and cartilage mineralization by impairing the homeostasis of the IHH and PTHrP/PTH1R feedback loop and ER stress. ERN1 may have a potential role as a new target for cartilage growth and maturation.

Advances in the extracellular signal-regulated kinase signaling pathway in silkworms, Bombyx mori (Lepidoptera)

Signaling pathways regulate the transmission of signals during organism growth and development, promoting the smooth and accurate completion of numerous physiological and biochemical reactions. The extracellular signal-regulated kinase (ERK) signaling pathway is an essential pathway involved in regulating various physiological processes, such as cell proliferation, differentiation, adhesion, migration, and more. This pathway also contributes to several important physiological processes in silkworms, including protein synthesis, reproduction, and immune defense against pathogens. Organizing related studies on the ERK signaling pathway in silkworms can provide a better understanding of its mechanism in Lepidopterans and develop a theoretical foundation for improving cocoon production and new strategies for pest biological control.

Potential Key Proteins, Molecular Networks, and Pathways in Perinatal Hypoxia

Perinatal hypoxia is a common risk factor for CNS development. Using bioinformatics databases, a list of 129 genes involved in perinatal hypoxia was selected from the literature and analyzed with respect to proteins important for biological processes influencing the brain development. Functional enrichment analysis using the DAVID database was performed to identify relevant Gene Ontology (GO) biological processes like response to hypoxia, inflammatory response, positive and negative regulation of apoptosis, and positive and negative regulation of cell proliferation. The selected GO processes contain 17-30 proteins and show an enrichment of 6.3-14.3-fold. The STRING protein-protein interaction network and the Cytoscape data analyzer were used to identify interacting proteins playing a significant role in these processes. The two top protein pairs referring to the proteins with highest degrees and the corresponding proteins connected by high score edges exert opposite or regulatory functions and are essential for the balance between damaging, repairing, protective, or epigenetic processes. The GO response to hypoxia is characterized by the high score protein-protein interaction pairs CASP3/FAS promoting apoptosis and by the protective acting BDNF/MECP2 protein pair. Core components of the GO processes positive and negative regulation of apoptosis are the proteins CASP3/FAS/AKT/eNOS/RPS6KB1 involved in several signal pathways. The GO processes cell proliferation are characterized by the high-score protein-protein interaction pairs MYC/ MAPK1, JUN/MAPK1, IL6/IL1B, and JUN/HDAC1. The study provides new insights into the pathophysiology of perinatal hypoxia and is of importance for future investigations, diagnostics, and therapy of perinatal hypoxia.

The Effects of Natural Product-Derived Extracts for Longitudinal Bone Growth: An Overview of In Vivo Experiments

Approximately 80% of children with short stature are classified as having Idiopathic Short Stature (ISS). While growth hormone (GH) treatment received FDA approval in the United States in 2003, its long-term impact on final height remains debated. Other treatments, like aromatase inhibitors, metformin, and insulin-like growth factor-1 (IGF-1), have been explored, but there is no established standard treatment for ISS. In South Korea and other Asian countries, East Asian Traditional Medicine (EATM) is sometimes employed by parents to potentially enhance their children's height growth, often involving herbal medicines. One such product, Astragalus membranaceus extract mixture HT042, claims to promote height growth in children and has gained approval from the Korean Food and Drug Administration (KFDA). Research suggests that HT042 supplementation can increase height growth in children without skeletal maturation, possibly by elevating serum IGF-1 and IGF-binding protein-3 levels. Preclinical studies also indicate the potential benefits of natural products, including of EATM therapies for ISS. The purpose of this review is to offer an overview of bone growth factors related to ISS and to investigate the potential of natural products, including herbal preparations, as alternative treatments for managing ISS symptoms, based on their known efficacy in in vivo studies.

Hydrogen peroxide-dependent oxidation of ERK2 within its D-recruitment site alters its substrate selection

Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are dysregulated in many pervasive diseases. Recently, we discovered that ERK1/2 is oxidized by signal-generated hydrogen peroxide in various cell types. Since the putative sites of oxidation lie within or near ERK1/2's ligand-binding surfaces, we investigated how oxidation of ERK2 regulates interactions with the model substrates Sub-D and Sub-F. These studies revealed that ERK2 undergoes sulfenylation at C159 on its D-recruitment site surface and that this modification modulates ERK2 activity differentially between substrates. Integrated biochemical, computational, and mutational analyses suggest a plausible mechanism for peroxide-dependent changes in ERK2-substrate interactions. Interestingly, oxidation decreased ERK2's affinity for some D-site ligands while increasing its affinity for others. Finally, oxidation by signal-generated peroxide enhanced ERK1/2's ability to phosphorylate ribosomal S6 kinase A1 (RSK1) in HeLa cells. Together, these studies lay the foundation for examining crosstalk between redox- and phosphorylation-dependent signaling at the level of kinase-substrate selection.

Atypical MAP kinases - new insights and directions from amoeba

Mitogen-activated protein kinases (MAPKs) have been the focus of many studies over the past several decades, but the understanding of one subgroup of MAPKs, orthologs of MAPK15, known as atypical MAPKs, has lagged behind others. In most organisms, specific activating signals or downstream responses of atypical MAPK signaling pathways have not yet been identified even though these MAPKs are associated with many eukaryotic processes, including cancer and embryonic development. In this Review, we discuss recent studies that are shedding new light on both the regulation and function of atypical MAPKs in different organisms. In particular, the analysis of the atypical MAPK in the amoeba Dictyostelium discoideum has revealed important roles in chemotactic responses and gene regulation. The rapid and transient phosphorylation of the atypical MAPK in these responses suggest a highly regulated activation mechanism in vivo despite the ability of atypical MAPKs to autophosphorylate in vitro. Atypical MAPK function can also impact the activation of other MAPKs in amoeba. These advances are providing new perspectives on possible MAPK roles in animals that have not been previously considered, and this might lead to the identification of potential targets for regulating cell movement in the treatment of diseases.

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.

Yangqing Chenfei formula alleviates silica-induced pulmonary inflammation in rats by inhibiting macrophage M1 polarization

BACKGROUND

Yangqing Chenfei formula (YCF) is a traditional Chinese medicine formula for early-stage silicosis. However, the therapeutic mechanism is unclear. The purpose of this study was to determine the mechanism for the effects of YCF on early-stage experimental silicosis.

METHODS

The anti-inflammatory and anti-fibrotic effects of YCF were determined in a silicosis rat model, which was established by intratracheal instillation of silica. The anti-inflammatory efficacy and molecular mechanisms of YCF were examined in a lipopolysaccharide (LPS)/interferon (IFN)-γ-induced macrophage inflammation model. Network pharmacology and transcriptomics were integrated to analyze the active components, corresponding targets, and anti-inflammatory mechanisms of YCF, and these mechanisms were validated in vitro.

RESULTS

Oral administration of YCF attenuated the pathological changes, reduced inflammatory cell infiltration, inhibited collagen deposition, decreased the levels of inflammatory factors, and reduced the number of M1 macrophages in the lung tissue of rats with silicosis. YCF5, the effective fraction of YCF, significantly attenuated the inflammatory factors induced by LPS and IFN-γ in M1 macrophages. Network pharmacology analysis showed that YCF contained 185 active components and 988 protein targets, which were mainly associated with inflammation-related signaling pathways. Transcriptomic analysis showed that YCF regulated 117 reversal genes mainly associated with the inflammatory response. Integrative analysis of network pharmacology and transcriptomics indicated that YCF suppressed M1 macrophage-mediated inflammation by regulating signaling networks, including the mTOR, mitogen-activated protein kinases (MAPK), PI3K-Akt, NF-κB, and JAK-STAT signaling pathways. In vitro studies confirmed that the active components of YCF significantly decreased the levels of p-mTORC1, p-P38, and p-P65 by suppressing the activation of related-pathways.

CONCLUSION

YCF significantly attenuated the inflammatory response in rats with silicosis via the suppression of macrophage M1 polarization by inhibiting a "multicomponent-multitarget-multipathway" network.

Establishment of Risk Model and Analysis of Immunoinfiltration Based on Mitophagy-Related Associated Genes in Atrial Fibrillation

Objective

Atrial fibrillation (AF) is a common tachyarrhythmia whose pathogenesis remains elusive. In the present study, we aimed to investigate the pathological mechanism of mitophagy and immunoinfiltration in AF.

Methods

First, we identified differentially expressed mitophagy-related genes (DEMRGs) based on the GSE79768 and GSE115574 datasets, subjecting them to functional enrichment analysis. STRING, TRRUST, miRNet, miRwalk, and Cytoscape were used to explore the potential regulatory roles of downstream signaling pathways. Subsequently, the random forest method was used to construct the AF risk model, and the DEMRGs most correlated with AF risk were determined by combining the Gini index. ssGSEA algorithm, NMF algorithm, and unsupervised clustering were used to subdivide AF molecular types. We then studied the characteristics of mitophagy- and immune infiltration-related genes in AF. Ultimately, we detected the expression of key genes in canine atrial tissues and HL-1 cells by immunofluorescence and Western blot.

Results

Mitophagy and immune infiltration were significantly enriched and activated in AF samples. Thirty-seven DEMRGs were screened, of which MAPK1, VDAC1, MAPK14, and MTERF3 were most associated with AF risk. The risk model based on these could identify patients at a high risk of AF. The infiltration of immunocells such as mast cells and neutrophils was significantly different among AF types. Finally, expression verification indicated that the expression trend of four key genes in canine atrial muscle tissue and HL-1 cells was consistent.

Conclusion

We found that mitophagy may participate in AF progression through immune activation. In addition, the AF risk prediction model composed of VDAC1, MAPK1, MAPK14, and MTERF3 has a good AF prediction performance, which provides new ideas for the study of AF pathogenesis and potential therapeutic targets.

Characterization of aberrant glycosylation associated with osteoarthritis based on integrated glycomics methods

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, affecting millions of aging people. Investigation of abnormal glycosylation is essential for the understanding of pathological mechanisms of OA.

METHODS

The total protein was isolated from OA (n = 13) and control (n = 11) cartilages. Subsequently, glycosylation alterations of glycoproteins in OA cartilage were investigated by lectin microarrays and intact glycopeptides analysis. Finally, the expression of glycosyltransferases involved in the synthesis of altered glycosylation was assessed by qPCR and GEO database.

RESULTS

Our findings revealed that several glycopatterns, such as α-1,3/6 fucosylation and high-mannose type of N-glycans were altered in OA cartilages. Notably, over 27% of identified glycopeptides (109 glycopeptides derived from 47 glycoproteins mainly located in the extracellular region) disappeared or decreased in OA cartilages, which is related to the cartilage matrix degradation. Interestingly, the microheterogeneity of N-glycans on fibronectin and aggrecan core protein was observed in OA cartilage. Our results combined with GEO data indicated that the pro-inflammatory cytokines altered the expression of glycosyltransferases (ALG3, ALG5, MGAT4C, and MGAT5) which may contribute to the alterations in glycosylation.

CONCLUSION

Our study revealed the abnormal glycopatterns and heterogeneities of site-specific glycosylation associated with OA. To our knowledge, it is the first time that the heterogeneity of site-specific N-glycans was reported in OA cartilage. The results of gene expression analysis suggested that the expression of glycosyltransferases was impacted by pro-inflammatory cytokines, which may facilitate the degradation of protein and accelerate the process of OA. Our findings provide valuable information for the understanding of molecular mechanisms in the pathogenesis of OA.

Advances in traditional Chinese medicine for the treatment of chronic obstructive pulmonary disease

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and thus imposes heavy economic burden on patients, their families, and society. Furthermore, COPD seriously affects the quality of life of patients. The concept of "overall regulation" of traditional Chinese medicine (TCM) plays an important role in the prevention and treatment of COPD.

AIM OF THE STUDY

The objective of this review is to summarize the TCM theories, experimental methods, TCM extracts, active TCM ingredients, and TCM formulas for the treatment of COPD and reveal the effects and mechanisms of TCM treatments on COPD.

MATERIALS AND METHODS

This article reviewed literature on TCM-based treatments for COPD reported from 2016 to 2021. Relevant scientific studies were obtained from databases that included PubMed, China National Knowledge Infrastructure, Web of Science, Google Scholar, The Plant List, ScienceDirect, and SciFinder.

RESULTS

This review summarized TCM-based theory, experimental methods, active ingredients, and potential toxicities, the effects of TCM extracts and formulations, and their mechanisms for the treatment of COPD. Most investigators have used in vivo models of cigarette smoke combined with lipopolysaccharide induction in rats and in vitro models of cigarette smoke extract induction. The active ingredients of TCM used for the treatment of COPD in relevant studies were triterpenoids, flavonoids, phenolics, quinones, glycosides, and alkaloids. TCMs commonly used in the treatment of COPD include antipyretic drugs, tonic medicines, anticough medications, and asthma medications. TCM can treat COPD by suppressing inflammation, reducing oxidative stress, inhibiting apoptosis, and improving airway remodeling.

CONCLUSIONS

This review enriches the theory of COPD treatments based on TCM, established the clinical significance and development prospects of TCM-based COPD treatments, and provided the necessary theoretical support for the further development of TCM resources for the treatment of COPD.

Missense polymorphisms potentially involved in mandibular prognathism

Objective

The current study aimed to identify and analyze missense single nucleotide polymorphisms (SNPs) that can potentially cause mandibular prognathism.

Methods

After reviewing the articles, 56 genes associated with mandibular prognathism were identified and their missense SNPs were retrieved from the NCBI website. Several web-based tools including CADD, PolyPhen-2, PROVEAN, SNAP2, PANTHER, FATHMM, and PON-P2 were used to filter out harmful SNPs. Additionally, ConSurf determined the level of evolutionary conservation at positions where SNPs occur. I-Mutant2 and MUpro predicted the effect of SNPs on protein stability. Furthermore, to investigate the structural and functional changes of proteins, HOPE and LOMETS tools were utilized.

Results

Based on predictions in at least four web-based tools, the results indicated that PLXNA2-rs4844658, DUSP6-rs2279574, and FBN3-rs33967815 are harmful. These SNPs are located at positions with variable or average conservation and have the potential to reduce the stability of their respective proteins. Moreover, they may impair protein activity by causing structural and functional changes.

Conclusions

In this study, we identified PLXNA2-rs4844658, DUSP6-rs2279574, and FBN3-rs33967815 as potential risk factors for mandibular prognathism using several web-based tools. According to the possible roles of PLXNA2, DUSP6, and FBN3 proteins in ossification pathways, we recommend that these SNPs be investigated further in experimental research. Through such studies, we hope to gain a better understanding of the molecular mechanisms involved in mandible formation.

Licochalcone A Inhibits Prostaglandin E2 by Targeting the MAPK Pathway in LPS Activated Primary Microglia

Neuroinflammation and oxidative stress are conditions leading to neurological and neuropsychiatric disorders. Natural compounds exerting anti-inflammatory and anti-oxidative effects, such as Licochalcone A, a bioactive flavonoid present in a traditional Chinese herb (licorice), might be beneficial for the treatment of those disorders. Therefore, this study aimed to investigate the anti-inflammatory and anti-oxidative effects of Licochalcone A in LPS-activated primary rat microglia. Licochalcone A dose-dependently prevented LPS-induced PGE₂ release by inhibiting the arachidonic acid (AA)/cylcooxygenase (COX) pathway decreasing phospholipase A2, COX-1, and COX-2 protein levels. Furthermore, LPS-induced levels of the cytokines IL-6 and TNFα were reduced by Licochalcone A, which also inhibited the phosphorylation and, thus, activation of the mitogen-activated protein kinases (MAPK) p38 MAPK and Erk 1/2. With the reduction of 8-iso-PGF_2α, a sensitive marker for oxidative stress, anti-oxidative effects of Licochalcone A were demonstrated. Our data demonstrate that Licochalcone A can affect microglial activation by interfering in important inflammatory pathways. These in vitro findings further demonstrate the potential value of Licochalcone A as a therapeutic option for the prevention of microglial dysfunction related to neuroinflammatory diseases. Future research should continue to investigate the effects of Licochalcone A in different disease models with a focus on its anti-oxidative and anti-neuroinflammatory properties.

Anti-inflammatory activity of Echinosophora koreensis nakai root extract in lipopolysaccharides-stimulated RAW 264.7 cells and carrageenan-induced mouse paw edema model

ETHNOPHARMACOLOGICAL RELEVANCE

Echinosophora koreensis Nakai is an endemic plant species distributed in a limited area within the Korean province of Gangwon, including the Yanggu-gun, Inje-gun, Cheorwon-gun, Chuncheon-si, and Hongcheon-gun counties. It is used in traditional medicine to treat various disorders, such as fever, skin diseases, diuresis, and neuralgia.

MATERIALS AND METHODS

This study demonstrated the effects of E. koreensis Nakai root extract (EKRE) on lipopolysaccharide (LPS)-induced inflammatory responses in vitro and in vivo. Cell viability was assessed through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Nitric oxide (NO) production was measured using Griess reagent. Interleukin (IL)-6 and tumor necrosis factor (TNF) levels were assessed using enzyme-linked immunosorbent assays. Inducible nitric oxide synthase (iNOS), nuclear factor kappa-B (NF-κB), and mitogen-activated protein kinase (MAPK) expression were assessed using Western blot analysis. To examine the effects of EKRE in vivo, it was administered orally at doses of 50 or 200 mg/kg for 3 days in mice. Edema in the paws was induced through λ-carrageenan injection and measured hourly for up to 5 h using calipers.

RESULTS

EKRE markedly suppressed LPS-generated NO, IL-6, and iNOS production in RAW 264.7 cells. Moreover, it suppressed the activation of the NF-κB and MAPK in LPS-stimulated cells. Furthermore, EKRE significantly inhibited carrageenan-induced edema in mouse paws. There were no significant differences in IL-6 and TNF production in paw tissue harvested from mice, but levels decreased at high EKRE concentrations (200 mg/kg).

CONCLUSION

The results of this study provided validation for EKRE-induced inhibition of inflammatory responses in vitro and in vivo. This research suggested that EKRE is a promising treatment for inflammatory disorders.

Activating Protein-1 (AP-1): A Promising Target for the Treatment of Fibrotic Diseases

The fibrosis of tissues and organs occurs via an aberrant tissue remodeling process characterized by an excessive deposition of extracellular matrix, which can lead to organ dysfunction, organ failure, and death. Because the pathogenesis of fibrosis remains unclear and elusive, there is currently no medication to reverse it; hence, this process deserves further study. Activating protein-1 (AP-1)-comprising Jun (c-Jun, JunB, JunD), Fos (c-fos, FosB, Fra1, and Fra2), and activating transcription factor-is a versatile dimeric transcription factor. Numerous studies have demonstrated that AP-1 plays a crucial role in advancing tissue and organ fibrosis via induction of the expression of fibrotic molecules and activating fibroblasts. This review focuses on the role of AP-1 in a range of fibrotic disorders as well as on the antifibrotic effects of AP-1 inhibitors. It also discusses the potential of AP-1 as a new therapeutic target in conditions involving tissue and organ fibrosis.

Nanoparticles Targeting Delivery Antagomir-483-5p to Bone Marrow Mesenchymal Stem Cells Treat Osteoporosis by Increasing Bone Formation

BACKGROUND

Promoting bone marrow mesenchymal stem cell (BMSC) osteoblastic differentiation is a promising therapeutic strategy for osteoporosis (OP). The present study demonstrates that miR- 483-5p inhibits the osteogenic differentiation of BMSCs. Therefore, selectively delivering the nanoparticles carrying antagomir-483-5p (miR-483-5p inhibitor) to BMSCs is expected to become an effective treatment drug for OP.

METHODS

Real-time PCR assays were used to analyze miR-483-5p, ALP and Bglap levels in BMSCs of ovariectomized and aged osteoporotic mice. Immunoglobulin G and poloxamer-188 encapsulated the functional small molecules, and a BMSC-targeting aptamer was employed to confirm the direction of the nanoparticles to selectively and efficiently deliver antagomir-483-5p to BMSCs in vivo. Luciferase assays were used to determine the target genes of miR-483-5p. Western blot assays and immunohistochemistry staining were used to detect the targets in vitro and in vivo.

RESULTS

miR-483-5p levels were increased in BMSCs of ovariectomized and aged osteoporotic mice. Inhibiting miR-483-5p levels in BMSCs by antagomir-483-5p in vitro promoted the expression of bone formation markers, such as ALP and Bglap. The FAM-BMSC-aptamer-nanoparticles carrying antagomir- 483-5p were taken up by BMSCs, resulting in stimulation of BMSC osteoblastic differentiation in vitro and osteoporosis prevention in vivo. Furthermore, our research demonstrated that mitogen-activated protein kinase 1 (MAPK1) and SMAD family member 5 (Smad5) were direct targets of miR-483-5p in regulating BMSC osteoblastic differentiation and osteoporosis pathological processes.

CONCLUSIONS

The important therapeutic role of FAM-BMSC-aptamer-nanoparticles carrying antagomir- 483-5p in osteoporosis was established in our study. These nanoparticles are a novel candidate for the clinical prevention and treatment of osteoporosis. The optimized, targeted drug delivery platform for small molecules will provide new ideas for treating clinical diseases.

Research advances in the role of MAPK cascade in regulation of cell growth, immunity, inflammation, and cancer

Mitogen-activated protein kinase (MAPK) cascade system is one of the highly conserved signal systems in eukaryotic cells, which participates in the regulation of many biological processes. Under the stimulation of different signals (such as cytokines, neurotransmitters, and hormones), MAPK cascade activates downstream targets and controls a variety of cellular processes, including growth, immunity, inflammation, and stress response. In different cells, the effects of MAPK cascade on cells vary with the stimuli and the duration of stimulation. MAPK cascade induces Th differentiation and participates in T cell receptor signal pathway and B cell receptor signal pathway. MAPK cascades regulate various cellular activities related to the occurrence and development of cancer. A thorough and systematic understanding of the specific regulatory effects of MAPK cascade on various cellular processes will provide theoretical guidance for treating various diseases.

Serum Levels of CXCR4, SDF-1, MCP-1, NF-κB and ERK1/2 in Patients with Skeletal Fluorosis

C-X-C motif chemokine receptor 4 (CXCR4), stromal cell-derived factor-1 (SDF-1), monocyte chemoattractant protein-1 (MCP-1), extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) affect bone cells and play an important role in bone and joint diseases, but the data on CXCR4, SDF-1, MCP-1, ERK1/2 and NF-κB in the serum of skeletal fluorosis (SF) patients are inconclusive. Thus, according to the "Diagnostic Criteria for Endemic Skeletal Fluorosis" (WS 192-2008), we enrolled patients with SF (n = 60) as the SF group and those without SF as the controls (n = 60). Serum levels of CXCR4, SDF-1, MCP-1, ERK1/2 and NF-κB were detected by enzyme-linked immunosorbent assays (ELISAs). Serum SDF-1, CXCR4, MCP-1 and NF-κB levels were significantly higher in the SF group than in the control group. Within the serum of SF patients, CXCR4 and SDF-1 levels were positively correlated with NF-κB levels. There was no correlation between MCP-1 levels and those of ERK1/2 or NF-κB. SDF-1 and CXCR4 may activate the NF-κB pathway, and MCP-1 affects the occurrence and development of SF by regulating osteocytes through other pathways. The SDF-1/CXCR4 axis and MCP-1 signalling pathway provide a new theoretical basis for the occurrence and development of SF.

The effect of ARVs on the MEKKK1 gene promoter, inflammatory cytokine expression and signalling in acute treated Jurkat T cells

ARVs alter the methylation status of the MEKKK1 gene promoter in acute treated Jurkat T cells with inflammatory outcomesInflammation is reduced in patients under going antiretroviral therapy; however the mechanism is not well understood. We investigated DNA methylation of the mitogen-activated protein kinase kinase kinase kinase 1 (MEKKK1) gene promoter in Jurkat T cells to determine whether the antiretroviral drugs, lamivudine, tenofovir disoproxil fumarate, dolutegravir, TLD (a combination of TDF, 3TC and DTG) and efavirenz modify the methylation status of the MEKKK1 gene - a known stimulus of inflammation.Acute antiretroviral treatments (24 h) were not cytotoxic to Jurkat T cells. MEKKK1 promoter hypomethylation occurred in cells treated with 5-aza-2'-deoxycytidine (Aza), TDF and 3TC, and MEKKK1 promoter hypermethylation occurred in cells treated with DTG; however, promoter DNA methylation of the MEKKK1 gene did not influence MEKKK1 gene expression; therefore, these drugs did not epigenetically regulate MEKKK1 and downstream signalling by promoter DNA methylation. Acute TLD and EFV treatments induced inflammation in Jurkat T cells by increasing MEKKK1, MAPK/ERK and NFκB expression, and activating tumour necrosis factor-α (TNF-α) expression. ARVs decreased IL-10 gene expression, showing no anti-inflammatory activity.The data shows that the inflammation caused by ARVs is not related to the methylation status of MEKKK1 gene promoter and suggests an alternative stimulus via post-transcriptional/post-translational modifications may activate the canonical MEKKK1/NFκB pathway that leads to inflammation. Finally, an increase in NFκB activity and pro-inflammatory cytokine activation seemed to occur via the MAPK/ERK pathway following ARV treatments in Jurkat T cells.

Molecular mechanism and potential therapeutic targets of liver metastasis from gastric cancer

Gastric cancer (GC) is characterized by high invasion and poor prognosis. The occurrence of liver metastasis seriously affects advanced GC prognosis. In recent years, great progress has been made in the field of GC liver metastasis. The abnormal expression of related genes leads to the occurrence of GC liver metastasis through metastasis cascades. The changes in the liver microenvironment provide a pre-metastasis condition for GC cells to colonize and grow. The development of several potential therapeutic targets might provide new therapeutic strategies for its treatment. Therefore, we reviewed the regulatory mechanism of abnormal genes mediating liver metastasis, the effect of liver resident cells on liver metastasis, and potential therapeutic targets, hoping to provide a novel therapeutic option to improve the quality of life and prognosis of GC patients with liver metastasis.

First evidence of dermo-protective activity of marine sulfur-containing histidine compounds

Among natural products, ovothiol (ovo), produced by marine invertebrates, bacteria, and microalgae, is receiving increasing interest for its unique antioxidant properties. Recently, ovo has been shown to exhibit anti-inflammatory activity in an in vitro model of endothelial dysfunction and in an in vivo model of liver fibrosis. The aim of this study was to evaluate the effect of ovo and its precursor 5-thiohistidine (5-thio) in comparison with ergothioneine (erg), in human skin cells and tissues upon inflammation. We used both an in vitro and ex vivo model of human skin, represented by a keratinocytes cell line (HaCaT) and skin biopsies, respectively. We observed that ovo, 5-thio, and erg were not cytotoxic in HaCaT cells, but instead exerted a protective function against TNF-α -induced inflammation. In order to get insights on their mechanism of action, we performed western blot analysis of ERK and JNK, as well as sub-cellular localization of Nrf2, a key mediator of the anti-inflammatory response. The results indicated that the pre-treatment with ovo, 5-thio, and erg differently affected the phosphorylation of ERK and JNK. However, all the three molecules promoted the accumulation of Nrf2 in the nucleus of HaCaT cells. In addition, gene expression analysis by RTqPCR and ELISA assays performed in ex vivo human skin tissues pre-treated with thiohistidines and then inflamed with IL-1β revealed a significant downregulation of IL-8, TNF-α and COX-2 genes and a concomitant significant decrease in the cytokines IL-6, IL-8 and TNF-α production. Moreover, the protective action of ovo and 5-thio resulted to be stronger when compared with dexamethasone, a corticosteroid drug currently used to treat skin inflammatory conditions. Our findings suggest that ovo and 5-thio can ameliorate skin damage and may be used to develop natural skin care products to prevent the inflammatory status induced by environmental stressors and aging.

Mangiferin promotes osteogenic differentiation and alleviates osteoporosis in the ovariectomized mouse via the AXL/ERK5 pathway

Mangiferin is a xanthone glucoside extracted from multiple plants, which has been shown to inhibit bone resorption and alleviate osteoporosis. However, the effect of purified Mangiferin on osteoporosis and its specific mechanisms is unknown. This study aimed to explore whether Mangiferin can promote osteogenic differentiation and alleviate osteoporosis in ovariectomized (OVX) mice and explore the potential mechanisms. Different concentrations and durations of Mangiferin were applied to MC3T3-E1 cells. The optimal concentration and duration of Mangiferin were determined by evaluating the cell viability via cell count kit-8 (CCK-8). The gene and protein expressions of AXL, ERK5, and osteogenic differentiation markers, including BMP2, Collagen1, OPN, Osterix, and Runx2, were detected using western blotting, qRT-PCR, immunofluorescence, and flow cytometry. Mangiferin was administered to OVX mice, and the severity of osteoporosis was evaluated by H and E staining, immunohistochemistry (IHC), microscopic computed-tomography (micro-CT) scanning, western blotting, and immunofluorescence of bone tissue. We found that Mangiferin promoted osteogenic differentiation in a dose-dependent manner at concentrations less than 30 μM. The 30 μM Mangiferin significantly upregulated the expression of AXL, ERK5, and osteogenic differentiation, including the ALP activity, percentage of alizarin red, and the levels of osteogenic differentiation markers. However, these expression levels decreased when AXL was knocked down in MC3T3-E1 cells and it could not be rescued by Mangiferin. Mangiferin relieved osteoporosis in OVX mice without causing severe organ damage. This study concluded that Mangiferin promoted osteogenic differentiation of MC3T3-E1 cells and alleviated osteoporosis in OVX mice. The potential mechanism was via the AXL/ERK5 pathway.

Baiying qingmai formulation ameliorates thromboangiitis obliterans by inhibiting HMGB1/RAGE/NF-κB signaling pathways

Baiying Qingmai Formulation (BF) is a classical clinical prescription used for decades to treat thromboangiitis obliterans (TAO). Although it effectively relieves pain and ischemic ulcers in patients with TAO, its anti-TAO mechanisms remain unclear. The chemical components of BF were analyzed using high-performance liquid chromatography and the potential targets of the compounds identified in BF were analyzed using molecular docking. Further, the signaling pathways and molecular mechanism of BF in treating TAO were studied using a rat model of TAO. Seven compounds (gallic acid, catechin, chlorogenic acid, caffeic acid, paeoniflorin, quercetin, and paeonol) were identified in BF, and molecular docking predicted their high affinities with HMGB1/RAGE/NF-κB proteins. In in vivo studies, BF not only inhibited the protein expression of HMGB1, RAGE, ICAM-1, and VCAM-1; mRNA levels of HMGB1 and RAGE; and the phosphorylation of NF-κB, ERK, Janus kinase (JNK) and p38 MAPK in the femoral artery, but also reduced the levels of inflammatory cytokines (IL-6, TNF-α, IL-1β, HMGB1) and stable metabolite (TXB2) of cytokine promoting thrombosis (TXA2) in the plasma. Moreover, BF stimulated the secretion of stable metabolite (6-keto-PGF1α) of cytokine inhibiting thrombosis (PGI2) in the plasma. BF inhibited the inflammatory response and thrombosis in the femoral artery, thus reducing the degree of vascular occlusion, which alleviated the symptoms in rats with TAO. Our findings suggest that BF ameliorates TAO by inhibiting the activation of the ERK, JNK, p38 MAPK and HMGB1/RAGE/NF-κB signaling pathways, thereby providing novel ideas for the treatment of TAO and essential information for the further development and utilization of BF as a promising drug to treat TAO.

Revealing the mechanisms of Weishi Huogu I capsules used for treating osteonecrosis of the femoral head based on systems pharmacology with one mechanism validated with in vitro experiments

ETHNOPHARMACOLOGICAL RELEVANCE

Weishi Huogu I (WH I) capsules, developed through traditional Chinese medicine, have been used to treat clinical osteonecrosis of the femoral head (ONFH) for decades. However, the mechanisms have not been systematically studied.

AIM OF THE STUDY

In this study, the mechanisms of WH I capsules used in treating ONFH were examined through a systems pharmacology strategy, and one mechanism was validated with in vitro experiments.

MATERIALS AND METHODS

WH I capsules compounds were identified by screening databases; then, a database of the potential active compounds was constructed after absorption, distribution, metabolism and excretion (ADME) evaluation. The compounds were identified through a systematic approach in which the probability of an interaction of every candidate compound with each corresponding target in the DrugBank database was calculated. Gene Ontology (GO) and pathway enrichment analyses of the targets was performed with the Metascape and KEGG DISEASE databases. Then, a compound-target network (C-T) and target-pathway network (T-P) of WH I capsule components were constructed, and network characteristics and related information were used for systematically identifying WH I capsule multicomponent-target interactions. Furthermore, the effects of WH I capsule compounds identified through the systematic pharmacology analysis of the osteogenic transformation of human umbilical mesenchymal stem cells (HUMSCs) were validated in vitro.

RESULTS

In total, 152 potentially important compounds and 176 associated targets were identified. Twenty-two crucial GO biological process (BP) or pathways were related to ONFH, mainly in regulatory modules regulating blood circulation, modulating growth, and affecting pathological processes closely related to ONFH. Furthermore, the GO enrichment analysis showed that corydine, isorhamnetin, and bicuculline were enriched in "RUNX2 regulates osteoblast differentiation", significantly increased alkaline phosphatase activity and calcium deposition and upregulated runt-related transcription factor 2 mRNA and protein expression and osteocalcin mRNA expression in HUMSCs, suggesting that these compounds promoted the mesenchymal stem cell (MSC) osteogenic transformation.

CONCLUSIONS

The study showed that the pharmacological mechanisms of WH I capsule attenuation of ONFH mainly involve three therapeutic modules: blood circulation, modulating growth, and regulating pathological processes. The crosstalk between GOBPs/pathways may constitute the basis of the synergistic effects of the compounds in WH I capsules in attenuating ONFH. One of the pharmacological mechanisms in the WH I capsule effect on ONFH involves enhancement of the osteogenic transformation of MSCs, as validated in experiments performed in vitro; however, more mechanisms should be validated in further studies.

Knockdown of FOXA1 enhances the osteogenic differentiation of human bone marrow mesenchymal stem cells partly via activation of the ERK1/2 signalling pathway

Background

The available therapeutic options for large bone defects remain extremely limited, requiring new strategies to accelerate bone healing. Genetically modified bone mesenchymal stem cells (BMSCs) with enhanced osteogenic capacity are recognised as one of the most promising treatments for bone defects.

Methods

We performed differential expression analysis of miRNAs between human BMSCs (hBMSCs) and human dental pulp stem cells (hDPSCs) to identify osteogenic differentiation-related microRNAs (miRNAs). Furthermore, we identified shared osteogenic differentiation-related miRNAs and constructed an miRNA-transcription network. The Forkhead box protein A1 (FOXA1) knockdown strategy with a lentiviral vector was used to explore the role of FOXA1 in the osteogenic differentiation of MSCs. Cell Counting Kit-8 was used to determine the effect of the knockdown of FOXA1 on hBMSC proliferation; real-time quantitative reverse transcription PCR (qRT-PCR) and western blotting were used to investigate target genes and proteins; and alkaline phosphatase (ALP) staining and Alizarin Red staining (ARS) were used to assess ALP activity and mineral deposition, respectively. Finally, a mouse model of femoral defects was established in vivo, and histological evaluation and radiographic analysis were performed to verify the therapeutic effects of FOXA1 knockdown on bone healing.

Results

We identified 22 shared and differentially expressed miRNAs between hDPSC and hBMSC, 19 of which were downregulated in osteogenically induced samples. The miRNA-transcription factor interaction network showed that FOXA1 is the most significant and novel osteogenic differentiation biomarker among more than 300 transcription factors that is directly targeted by 12 miRNAs. FOXA1 knockdown significantly promoted hBMSC osteo-specific genes and increased mineral deposits in vitro. In addition, p-ERK1/2 levels were upregulated by FOXA1 silencing. Moreover, the increased osteogenic differentiation of FOXA1 knockdown hBMSCs was partially rescued by the addition of ERK1/2 signalling inhibitors. In a mouse model of femoral defects, a sheet of FOXA1-silencing BMSCs improved bone healing, as detected by microcomputed tomography and histological evaluation.

Conclusion

These findings collectively demonstrate that FOXA1 silencing promotes the osteogenic differentiation of BMSCs via the ERK1/2 signalling pathway, and silencing FOXA1 in vivo effectively promotes bone healing, suggesting that FOXA1 may be a novel target for bone healing.

ERK1/2-RSK2 Signaling in Regulation of ERα-Mediated Responses

Signaling via extracellular regulated kinase 1/2 (ERK1/2) and p90 ribosomal S6 kinase (RSK), a downstream effector, mediates numerous processes. For example, ERK1/2-RSK signaling is essential for estrogen homeostasis in the mammary gland and uterus to maintain physiological responsiveness. This review will focus on the coordination of ERK1/2-RSK2 and estrogen signaling through estrogen receptor alpha (ERα). The interrelationship and the feedback mechanisms between these pathways occurs at the level of transcription, translation, and posttranslational modification. Identifying how ERK1/2-RSK2 and estrogen signaling cooperate in homeostasis and disease may lead to novel therapeutic approaches in estrogen-dependent disorders.

Experimental Bothrops atrox Envenomation: Blood Plasma Proteome Effects after Local Tissue Damage and Perspectives on Thromboinflammation

The clinical manifestations of Bothrops atrox envenoming involve local and systemic changes, among which edema requires substantial attention due to its ability to progress to compartmental syndromes and sometimes cause tissue loss and amputations. However, the impact of edema on the poisoned body’s system has not been explored. Thus, the present study aimed to explore the systemic pathological and inflammatory events that are altered by intraplantar injection of B. atrox venom in a mouse model through hematologic, lipidic, and shotgun proteomics analysis. Plasma samples collected showed a greater abundance of proteins related to complement, coagulation, lipid system, platelet and neutrophil degranulation, and pathways related to cell death and ischemic tolerance. Interestingly, some proteins, in particular, Prdx2 (peroxiredoxin 2), Hba (hemoglobin subunit alpha), and F9 (Factor IX), increased according to the amount of venom injected. Our findings support that B. atrox venom activates multiple blood systems that are involved in thromboinflammation, an observation that may have implications for the pathophysiological progression of envenomations. Furthermore, we report for the first time a potential role of Prdx2, Hba, and F9 as potential markers of the severity of edema/inflammation in mice caused by B. atrox.

Dental Pulp-Derived Stem Cells Reduce Inflammation, Accelerate Wound Healing and Mediate M2 Polarization of Myeloid Cells

This work aimed to validate the potential use of dental pulp-derived stem cells (DPSCs) for the treatment of inflammation by defining their mechanisms of action. We planned to investigate whether priming of DPSC with proinflammatory molecules had any impact on their behavior and function. In the first step of our validation in vitro, we showed that priming of DPSCs with the bioactive agents LPS, TNF-α, or IFN-γ altered DPSCs’ immunologic properties by increasing their expression levels of IL-10, HGF, IDO, and IL-4 and by decreasing their mitochondrial functions. Moreover, DPSCs induced accelerated wound healing irrespective of priming, as determined by using a gut epithelial cell line in a scratch wound assay. Wound healing of gut epithelial cells was mediated by regulating the expressions of AKT, NF-κB, and ERK1/2 proteins compared to the control epithelial cells. In addition, primed DPSCs altered monocyte polarization toward an immuno-suppressive phenotype (M2), where monocytes expressed higher levels of IL-4R, IL-6, Arg1, and YM-1 compared to monocytes cultured with control DPSCs. In silico analysis revealed that this was accomplished in part by the interaction between kynurenine and PPARγ, which regulated the expression of M2 differentiation-related genes. Collectively, these data provided evidence that the DPSCs reduced inflammation, induced M2 polarization of myeloid cells, and healed damaged gut epithelial cells through inactivation of inflammation and modulating constitutively active signaling pathways.

Anti‐inflammatory properties of lemon‐derived extracellular vesicles are achieved through the inhibition of ERK / NF‐κB signalling pathways

Chronic inflammation is associated with the occurrence of several diseases. However, the side effects of anti‐inflammatory drugs prompt the identification of new therapeutic strategies. Plant‐derived extracellular vesicles (PDEVs) are gaining increasing interest in the scientific community for their biological properties. We isolated PDEVs from the juice of Citrus limon L. (LEVs) and characterized their flavonoid, limonoid and lipid contents through reversed‐phase high‐performance liquid chromatography coupled to electrospray ionization quadrupole time‐of‐flight mass spectrometry (RP‐HPLC–ESI‐Q‐TOF‐MS). To investigate whether LEVs have a protective role on the inflammatory process, murine and primary human macrophages were pre‐treated with LEVs for 24 h and then were stimulated with lipopolysaccharide (LPS). We found that pre‐treatment with LEVs decreased gene and protein expression of pro‐inflammatory cytokines, such as IL‐6, IL1‐β and TNF‐α, and reduced the nuclear translocation and phosphorylation of NF‐κB in LPS‐stimulated murine macrophages. The inhibition of NF‐κB activation was associated with the reduction in ERK1‐2 phosphorylation. Furthermore, the ability of LEVs to decrease pro‐inflammatory cytokines and increase anti‐inflammatory molecules was confirmed ex vivo in human primary T lymphocytes. In conclusion, we demonstrated that LEVs exert anti‐inflammatory effects both in vitro and ex vivo by inhibiting the ERK1‐2/NF‐κB signalling pathway.

Screening and Isolation of Potential Anti-Inflammatory Compounds from Saxifraga atrata via Affinity Ultrafiltration-HPLC and Multi-Target Molecular Docking Analyses

In this study, a 100 g sample of Saxifraga atrata was processed to separate 1.3 g of 11-O-(4′-O-methylgalloyl)-bergenin (Fr1) after 1 cycle of MCI GEL® CHP20P medium pressure liquid chromatography using methanol/water. Subsequently, COX-2 affinity ultrafiltration coupled with reversed-phase liquid chromatography was successfully used to screen for potential COX-2 ligands in this target fraction (Fr1). After 20 reversed-phase liquid chromatography runs, 74.1 mg of >99% pure 11-O-(4′-O-methylgalloyl)-bergenin (Fr11) was obtained. In addition, the anti-inflammatory activity of 11-O-(4′-O-methylgalloyl)-bergenin was further validated through molecular docking analyses which suggested it was capable of binding strongly to ALOX15, iNOS, ERBB2, SELE, and NF-κB. As such, the AA metabolism, MAPK, and NF-κB signaling pathways were hypothesized to be the main pathways through which 11-O-(4′-O-methylgalloyl)-bergenin regulates inflammatory responses, potentially functioning by reducing pro-inflammatory cytokine production, blocking pro-inflammatory factor binding to cognate receptors and inhibiting the expression of key proteins. In summary, affinity ultrafiltration-HPLC coupling technology can rapidly screen for multi-target bioactive components and when combined with molecular docking analyses, this approach can further elucidate the pharmacological mechanisms of action for these compounds, providing valuable information to guide the further development of new multi-target drugs derived from natural products.

CXCL16/ERK1/2 pathway regulates human podocytes growth, migration, apoptosis and epithelial mesenchymal transition

Primary nephrotic syndrome (PNS) is the commonest glomerular disease affecting children. Previous studies have confirmed that CXC motif chemokine ligand 16 (CXCL16) is involved in the pathogenesis of PNS. However, the exact mechanisms underlying the pathogenesis of PNS remain to be elucidated. Thus, the present study aimed to elucidate the role of CXCL16 in PNS. It was found that the expression of CXCL16 and extracellular signal‑regulated kinases 1 and 2 (ERK1/2) were significantly increased in clinical PNS renal tissues using reverse transcription‑quantitative PCR, western blot analysis and immunohistochemistry. Lentivirus overexpression or short hairpin RNA vector was used to induce the overexpression or knockdown of CXCL16 in podocytes, respectively. Overexpression of CXCL16 in podocytes could decrease the cell proliferation and increase the migration and apoptosis, whereas CXCL16 knockdown increased cell proliferation and decreased cell migration and apoptosis. Results of the present study further demonstrated that ERK2 protein expression was regulated by CXCL16. The knockdown of ERK2 expression reversed the effects of CXCL16 on the proliferation, apoptosis, migration and epithelial mesenchymal transition (EMT) of podocytes. Collectively, the findings of the present study highlighted that the CXCL16/ERK1/2 pathway regulates the growth, migration, apoptosis and EMT of human podocytes.

Potential therapeutic application of biophenols - plants secondary metabolites in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease showed that persistent inflammation in the joints, induces the cartilage destruction, bone erosion, and leukocyte infiltration in the synovium. RA mostly affects the joints of hands, feet, wrists, ankles, and knees. Each year, approximately 20-40 new cases are reported per lac population and the disease affects women more than men. The etiology of RA is still unknown, but many pathways have been identified as potential targets in its pathophysiology, including the PI3K/AKT signaling pathway, NF-κB signaling, Adenosine signaling, Wnt, SYK/BTK, and mTOR signaling pathways. Biophenol, plant secondary metabolite, is considered one of the most abundantly phytoconstituents to have potential anti-inflammatory effects associated with multiple pathways. These indicate that biophenols can be used for its protective effect on the development and symptoms of RA. The current review explores and discusses the role of different biophenols in the treatment of RA disease.

Intermittent Theta Burst Stimulation Ameliorates Cognitive Deficit and Attenuates Neuroinflammation via PI3K/Akt/mTOR Signaling Pathway in Alzheimer’s-Like Disease Model

Neurodegeneration implies progressive neuronal loss and neuroinflammation further contributing to pathology progression. It is a feature of many neurological disorders, most common being Alzheimer’s disease (AD). Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive stimulation which modulates excitability of stimulated brain areas through magnetic pulses. Numerous studies indicated beneficial effect of rTMS in several neurological diseases, including AD, however, exact mechanism are yet to be elucidated. We aimed to evaluate the effect of intermittent theta burst stimulation (iTBS), an rTMS paradigm, on behavioral, neurochemical and molecular level in trimethyltin (TMT)-induced Alzheimer’s-like disease model. TMT acts as a neurotoxic agent targeting hippocampus causing cognitive impairment and neuroinflammation, replicating behavioral and molecular aspects of AD. Male Wistar rats were divided into four experimental groups–controls, rats subjected to a single dose of TMT (8 mg/kg), TMT rats subjected to iTBS two times per day for 15 days and TMT sham group. After 3 weeks, we examined exploratory behavior and memory, histopathological and changes on molecular level. TMT-treated rats exhibited severe and cognitive deficit. iTBS-treated animals showed improved cognition. iTBS reduced TMT-induced inflammation and increased anti-inflammatory molecules. We examined PI3K/Akt/mTOR signaling pathway which is involved in regulation of apoptosis, cell growth and learning and memory. We found significant downregulation of phosphorylated forms of Akt and mTOR in TMT-intoxicated animals, which were reverted following iTBS stimulation. Application of iTBS produces beneficial effects on cognition in of rats with TMT-induced hippocampal neurodegeneration and that effect could be mediated via PI3K/Akt/mTOR signaling pathway, which could candidate this protocol as a potential therapeutic approach in neurodegenerative diseases such as AD.

3,4-Dihydroxyphenylethanol (DPE or Hydroxytyrosol) Counteracts ERK1/2 and mTOR Activation, Pro-Inflammatory Cytokine Release, Autophagy and Mitophagy Reduction Mediated by Benzo[a]pyrene in Primary Human Colonic Epithelial Cells

Understanding the effects induced by carcinogens on primary colonic epithelial cells and how to counteract them might help to prevent colon cancer, which is one of the most frequent and aggressive cancers. In this study, we exposed primary human colonic epithelial cells (HCoEpC) to Benzo[a]pyrene (B[a]P) and found that it led to an increased production of pro-inflammatory cytokines and activated ERK1/2 and mTOR. These pathways are known to be involved in inflammatory bowel disease (IBD), which represents a colon cancer risk factor. Moreover, B[a]P reduced autophagy and mitophagy, processes whose dysregulation has been clearly demonstrated to predispose to cancer either by in vitro or in vivo studies. Interestingly, all the effects induced by B[a]P could be counteracted by 3,4-Dihydroxyphenylethanol (DPE or Hydroxytyrosol, H), the most powerful anti-inflammatory and antioxidant compound contained in olive oil. This study sheds light on the mechanisms that could be involved in colon carcinogenesis induced by a chemical carcinogen and identifies a safe natural product that may help to prevent them.