Differential regulation and properties of MAPKs

Membrane-bound trehalase enhances cadmium tolerance by regulating cell apoptosis in Neocaridina denticulata sinensis

Trehalase gene is mainly expressed in the digestive circulatory system for regulating energy metabolism and chitin synthesis in insects, but it is significantly expressed in gill for immunomodulation in shrimp. However, its function in regulating immunity, particularly metal resistance in crustaceans has yet to be elucidated. In this study, one Tre2 gene (NdTre2) was isolated from Neocaridina denticulata sinensis. It could bind to Cd2+ and inhibit its toxicity. Spatiotemporal expression analysis showed that the expression of NdTre2 was highest in the gill and significantly reduced at 12 h after Cd2+ stimulation. The transcriptomic analysis of the gill after NdTre2 knockdown showed that the expression of genes synthetizing 20E was up-regulated and the increased 20E could further induce apoptosis by activating the intrinsic mitochondrial pathway, exogenous death receptor-ligand pathway, and MAPK pathway. In vitro, overexpressing NdTre2 enhanced the tolerance of E. coli in Cd2+ environment. In summary, these results indicate that NdTre2 plays an essential role in regulating immunity and chitin metabolism in N. denticulata sinensis.

The 3,3'-dimethoxy-4,4'-dihydroxy-stilbene Triazole (STT) Inhibits Liver Cancer Cell Growth by Targeting Akt/mTOR Pathway

The present study was aimed to investigate the proliferation inhibitory ability of 3,3'-dimethoxy-4,4'-dihydroxy-stilbene triazole (STT) on SNU449 and Huh7 cells. Moreover, the mechanism associated with the suppression of liver cancer cell proliferation by STT was also studied. The results revealed that STT suppresses proliferation of SNU449 and Huh7 cells to 28 and 21%, respectively treatment with 20 µM. The clonogenic survival of SNU449 and Huh7 cells was also significantly reduced after incubation with STT compared to the control cultures. In comparison to the control, STT treatment significantly decreased the invasive potential of SNU449 cells. Treatment with STT led to a prominent suppression in p62 and increase in LC3B protein expression in SNU449 cells compared to the control cells. The STT treatment dramatically decreased p-Akt and p-mTOR protein expression in SNU449 cells. Docking study revealed that STT interacts via traditional hydrogen bonding with the glutamine, phenylalanine, leucine, serine, arginine, aspartic acid, and lysine residues of Akt protein. In summary, the current study demonstrates that STT effectively suppresses the viability of SNU449 and Huh7 liver cancer cells. Moreover, STT treatment of the liver cancer cells also significantly reduces the clonogenic survival and invasive potential of SNU449 cells. Treatment of liver cancer cells with STT increases the expression of autophagic, targets anti-autophagic protein expression and down-regulates Akt/mTOR pathway to inhibit cancer growth and proliferation. Thus, STT exhibits prominent anticancer effect and needs to be investigated further as a potential candidate for the treatment of liver cancer.

TG2 participates in pulmonary vascular remodelling by regulating the senescence of pulmonary artery smooth muscle cells

Pulmonary hypertension (PH) is a severe cardiovascular disease characterised by pulmonary vascular remodelling. The pivotal role of cellular senescence in vascular remodelling has been acknowledged. Transglutaminase type 2 (TG2), a calcium-dependent enzyme, is intricately linked to both cellular senescence and PH. However, the precise mechanisms underlying the involvement of TG2 in PH remain unclear. In this study, we explored the expression of TG2 and the cellular senescence marker p16INK4a in the pulmonary vasculature of mice with PH induced by hypoxia combined with SU5416. Our findings revealed upregulation of both TG2 and p16INK4a expression in the pulmonary vasculature of PH mice. Additionally, a notable increase in TG2 expression was observed in senescent pulmonary artery smooth muscle cells (PASMC). To delve deeper, we employed proteomic sequencing to reveal seven genes associated with cellular senescence, with a subsequent focus on MAPK14. Our investigation revealed that TG2 regulates senescence in PASMC by modulating the phosphorylation levels of MAPK14. Additionally, in the context of hypoxia combined with SU5416, our observations revealed a noteworthy reduction in both pulmonary vascular remodelling and senescent manifestations in smooth muscle-specific TG2 knockout mice compared with their wild-type counterparts. In summary, our findings indicate that TG2 deficiency lowers the senescence levels of PASMC by inhibiting the activity of MAPK14. This inhibition of senescence in the pulmonary vasculature of PH mice helps to decelerate the progression of pulmonary vascular remodelling and consequently hinders the onset and development of PH.

Weighted gene co-expression network analysis reveals genes related to growth performance in Hu sheep

Hu sheep are a unique breed in our country with great reproductive potential, the extent of whose breeding has been steadily rising in recent years. The study subjects in this experiment were 8-month-old Hu sheep (n = 112). First of all, the growth performance, slaughter performance and meat quality of their eye muscle quality were assessed, meanwhile their live weight, carcass weight, body length, body height, chest circumference, chest depth and tube circumference were respectively 33.81 ± 5.47 kg, 17.43 ± 3.21 kg, 60.36 ± 4.41 cm, 63.25 ± 3.88 cm, 72.03 ± 5.02 cm, 30.70 ± 2.32 cm and 7.36 ± 0.56 cm, with a significant difference between rams and ewes (P < 0.01). Following that, transcriptome sequencing was done, and candidate genes related to growth performance were identified using the weighted co-expression network analysis (WGCNA) approach, which was used to identified 15 modules, with the turquoise and blue modules having the strongest association with growth and slaughter performance, respectively. We discovered hub genes such as ARHGAP31, EPS8, AKT3, EPN1, PACS2, KIF1C, C12H1orf115, FSTL1, PTGFRN and IFIH1 in the gene modules connected with growth and slaughter performance. Our research identifies the hub genes associated with the growth and slaughter performance of Hu sheep, which play an important role in their muscle growth, organ and cartilage development, blood vessel development and energy metabolic pathways. Our findings might lead to the development of potentially-useful biomarkers for the selection of growth and slaughterer performance-related attributes of sheep and other livestock.

Advances of the MAPK pathway in the treatment of spinal cord injury

Spinal cord injury (SCI) represents a complex pathology within the central nervous system (CNS), leading to severe sensory and motor impairments. It activates various signaling pathways, notably the mitogen-activated protein kinase (MAPK) pathway. Present treatment approaches primarily focus on symptomatic relief, lacking efficacy in addressing the underlying pathophysiological mechanisms. Emerging research underscores the significance of the MAPK pathway in neuronal differentiation, growth, survival, axonal regeneration, and inflammatory responses post-SCI. Modulating this pathway post-injury has shown promise in attenuating inflammation, minimizing apoptosis, alleviating neuropathic pain, and fostering neural regeneration. Given its pivotal role, the MAPK pathway emerges as a potential therapeutic target in SCI management. This review synthesizes current knowledge on SCI pathology, delineates the MAPK pathway's characteristics, and explores its dual roles in SCI pathology and therapeutic interventions. Furthermore, it addresses the existing challenges in MAPK research in the context of SCI, proposing solutions to overcome these hurdles. Our aim is to offer a comprehensive reference for future research on the MAPK pathway and SCI, laying the groundwork for targeted therapeutic strategies.

Translational Relevance of Secondary Intracellular Signaling Cascades Following Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) is a life-threatening and life-altering condition that results in debilitating sensorimotor and autonomic impairments. Despite significant advances in the clinical management of traumatic SCI, many patients continue to suffer due to a lack of effective therapies. The initial mechanical injury to the spinal cord results in a series of secondary molecular processes and intracellular signaling cascades in immune, vascular, glial, and neuronal cell populations, which further damage the injured spinal cord. These intracellular cascades present promising translationally relevant targets for therapeutic intervention due to their high ubiquity and conservation across eukaryotic evolution. To date, many therapeutics have shown either direct or indirect involvement of these pathways in improving recovery after SCI. However, the complex, multifaceted, and heterogeneous nature of traumatic SCI requires better elucidation of the underlying secondary intracellular signaling cascades to minimize off-target effects and maximize effectiveness. Recent advances in transcriptional and molecular neuroscience provide a closer characterization of these pathways in the injured spinal cord. This narrative review article aims to survey the MAPK, PI3K-AKT-mTOR, Rho-ROCK, NF-κB, and JAK-STAT signaling cascades, in addition to providing a comprehensive overview of the involvement and therapeutic potential of these secondary intracellular pathways following traumatic SCI.

Depletion of Ppp6c in hematopoietic and vascular endothelial cells causes embryonic lethality and decreased hematopoietic potential

Protein phosphatase 6 (PP6) is a serine/threonine (Ser/Thr) protein phosphatase, and its catalytic subunit is Ppp6c. PP6 forms the PP2A subfamily with PP2A and PP4. The diverse phenotypes observed following small interfering RNA (siRNA)-based knockdown of Ppp6c in cultured mammalian cells suggest that PP6 plays roles in cell growth and DNA repair. There is also evidence that PP6 regulates nuclear factor kappa B (NF-κB) signaling and mitogen-activated protein kinases and inactivates transforming growth factor-β-activated kinase 1 (TAK1). Loss of Ppp6c causes several abnormalities, including those of T cell and regulatory T cell function, neurogenesis, oogenesis, and spermatogenesis. PP2A has been reported to play an important role in erythropoiesis. However, the roles of PP6 in other hematopoietic cells have not been investigated. We generated Ppp6cfl/fl;Tie2-Cre (Ppp6cTKO) mice, in which Ppp6c was specifically deleted in hematopoietic and vascular endothelial cells. Ppp6cTKO mice displayed embryonic lethality. Ppp6c deficiency increased the number of dead cells and decreased the percentages of erythroid and monocytic cells during fetal hematopoiesis. By contrast, the number of Lin-Sca-1+c-Kit+ cells, which give rise to all hematopoietic cells, was slightly increased, but their colony-forming cell activity was markedly decreased. Ppp6c deficiency also increased phosphorylation of extracellular signal-regulated kinase 1/2 and c-Jun amino (N)-terminal kinase in fetal liver hematopoietic cells.

pH-responsive targeted nanoparticles release ERK-inhibitor in the hypoxic zone and sensitize free gemcitabine in mutant K-Ras-addicted pancreatic cancer cells and mouse model

Therapeutic options for managing Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest types of aggressive malignancies, are limited and disappointing. Therefore, despite suboptimal clinical effects, gemcitabine (GEM) remains the first-line chemotherapeutic drug in the clinic for PDAC treatment. The therapeutic limitations of GEM are primarily due to poor bioavailability and the development of chemoresistance resulting from the addiction of mutant-K-RAS/AKT/ERK signaling-mediated desmoplastic barriers with a hypoxic microenvironment. Several new therapeutic approaches, including nanoparticle-assisted drug delivery, are being investigated by us and others. This study used pH-responsive nanoparticles encapsulated ERK inhibitor (SCH772984) and surface functionalized with tumor-penetrating peptide, iRGD, to target PDAC tumors. We used a small molecule, SCH772984, to target ERK1 and ERK2 in PDAC and other cancer cells. This nanocarrier efficiently released ERKi in hypoxic and low-pH environments. We also found that the free-GEM, which is functionally weak when combined with nanoencapsulated ERKi, led to significant synergistic treatment outcomes in vitro and in vivo. In particular, the combination approaches significantly enhanced the GEM effect in PDAC growth inhibition and prolonged survival of the animals in a genetically engineered KPC (LSL-KrasG12D/+/LSL-Trp53R172H/+/Pdx-1-Cre) pancreatic cancer mouse model, which is not observed in a single therapy. Mechanistically, we anticipate that the GEM efficacy was increased as ERKi blocks desmoplasia by impairing the production of desmoplastic regulatory factors in PDAC cells and KPC mouse tumors. Therefore, 2nd generation ERKi (SCH 772984)-iRGD-pHNPs are vital for the cellular response to GEM and denote a promising therapeutic target in PDAC with mutant K-RAS.

An insight into crosstalk among multiple signalling pathways contributing to the pathophysiology of PTSD and depressive disorders

Post-traumatic stress disorder (PTSD) and depressive disorders represent two significant mental health challenges with substantial global prevalence. These are debilitating conditions characterized by persistent, often comorbid, symptoms that severely impact an individual's quality of life. Both PTSD and depressive disorders are often precipitated by exposure to traumatic events or chronic stress. The profound impact of PTSD and depressive disorders on individuals and society necessitates a comprehensive exploration of their shared and distinct pathophysiological features. Although the activation of the stress system is essential for maintaining homeostasis, the ability to recover from it after diminishing the threat stimulus is also equally important. However, little is known about the main reasons for individuals' differential susceptibility to external stressful stimuli. The solution to this question can be found by delving into the interplay of stress with the cognitive and emotional processing of traumatic incidents at the molecular level. Evidence suggests that dysregulation in these signalling cascades may contribute to the persistence and severity of PTSD and depressive symptoms. The treatment strategies available for this disorder are antidepressants, which have shown good efficiency in normalizing symptom severity; however, their efficacy is limited in most individuals. This calls for the exploration and development of innovative medications to address the treatment of PTSD. This review delves into the intricate crosstalk among multiple signalling pathways implicated in the development and manifestation of these mental health conditions. By unravelling the complexities of crosstalk among multiple signalling pathways, this review aims to contribute to the broader knowledge base, providing insights that could inform the development of targeted interventions for individuals grappling with the challenges of PTSD and depressive disorders.

Potential Antitumor Activity of Combined Lycopene and Sorafenib against Solid Ehrlich Carcinoma via Targeting Autophagy and Apoptosis and Suppressing Proliferation

An FDA-approved kinase inhibitor called sorafenib (SOR) is used to treat primary kidney and liver cancer as well as to stop the spread of advanced breast cancer. Side effects from SOR, such as palmar-plantar erythrodysesthesia syndrome, can negatively impact an individual's quality of life. There are a lot of data supporting the importance of lycopene (LYC) in preventing cancer. The antitumor properties of the combination of sorafenib and lycopene were examined in this study. A viability test against MDA-MB-231 was used to assess the anticancer efficacy of sorafenib, lycopene, and their combination in vitro. Moreover, a cell cycle analysis and Annexin-V/PI double staining were performed by using flow cytometry. In addition, the protein level of JNK-1, ERK-1, Beclin-1, P38, and P53 of the MDA-MB-231 cell line was estimated using ELISA kits. In addition, mice with SEC were divided into four equal groups at random (n = 10) to investigate the possible processes underlying the in vivo antitumor effect. Group IV (SEC-SOR-LYC) received SOR (30 mg/kg/day, p.o.) and LYC (20 mg/kg/day, p.o.); Group I received the SEC control; Group II received SEC-SOR (30 mg/kg/day, p.o.); and Group III received SEC-LYC (20 mg/kg/day, p.o.). The findings demonstrated that the combination of sorafenib and lycopene was superior to sorafenib and lycopene alone in causing early cell cycle arrest, suppressing the viability of cancer cells, and increasing cell apoptosis and autophagy. Likewise, the combination of sorafenib and lycopene demonstrated inhibition of the levels of Bcl-2, Ki-67, VEGF, IL-1β, and TNF-α protein. Otherwise, the quantities of the proteins BAX, P53, and caspase 3 were amplified. Furthermore, the combined treatment led to a substantial increase in TNF-α, caspase 3, and VEGF gene expression compared to the equivalent dosages of monotherapy. The combination of sorafenib and lycopene enhanced apoptosis and reduced inflammation, as seen by the tumor's decreased weight and volume, hence demonstrating its potential anticancer effect.

Role of the Atypical MAPK ERK3 in Cancer Growth and Progression

Extracellular signal-regulated kinase 3 (ERK3) is an atypical mitogen-activated protein kinase (MAPK) whose structural and regulatory features are distinct from those of conventional MAPKs, such as ERK1/2. Since its identification in 1991, the regulation, substrates and functions of ERK3 have remained largely unknown. However, recent years have witnessed a wealth of new findings about ERK3 signaling. Several important biological functions for ERK3 have been revealed, including its role in neuronal morphogenesis, inflammation, metabolism, endothelial cell tube formation and epithelial architecture. In addition, ERK3 has been recently shown to play important roles in cancer cell proliferation, migration, invasion and chemoresistance in multiple types of cancers. Furthermore, accumulating studies have uncovered various molecular mechanisms by which the expression level, protein stability and activity of ERK3 are regulated. In particular, several post-translational modifications (PTMs), including ubiquitination, hydroxylation and phosphorylation, have been shown to regulate the stability and activity of ERK3 protein. In this review, we discuss recent findings regarding biochemical and cellular functions of ERK3, with a main focus on its roles in cancers, as well as the molecular mechanisms of regulating its expression and activity.

Role of MAPKs in TGF-β1-induced maturation and mineralization in human osteoblast-like cells

OBJECTIVES

Our study aimed to clarify the role of mitogen-activated protein kinases (MAPKs) in transforming growth factor (TGF)-β1-stimulated mineralization in the human osteoblast-like MG63 cells.

METHODS

The viability of MG63 cells under TGF-β1 stimulation was assessed by MTS assay. Western blotting determined TGF-β1-mediated activation of extracellular signal-related protein kinase (ERK), p38, and c-Jun amino-terminal kinase (JNK). Mineralization-related gene expression was examined by quantitative real-time PCR, and mineral deposition levels were evaluated by alizarin red S staining.

RESULTS

TGF-β1 had no effect on MG63 cell proliferation. Activation of p38 was observed at 3 h post TGF-β1 stimulation. Moreover, JNK phosphorylation was upregulated by TGF-β1 from 1 to 6 h post stimulation, but had no activation on ERK phosphorylation throughout the experimental period. Treatment with JNK inhibitor diminished the alizarin red S-stained area in a dose-dependent manner. Mineral deposition was unaffected by MEK inhibitor, whereas p38 inhibitor increased the red-stained area. Gene expression levels of ALP and BSP were significantly decreased under treatment with JNK inhibitor and p38 inhibitor. The MEK inhibitor had no effect on the TGF-β1-mediated upregulation of ALP and BSP. Although all three inhibitors suppressed expression of COL I, none were found to stimulate expression of OCN.

CONCLUSIONS

Human osteoblast-like MG63 cells maturation and mineralization are induced through JNK activation of MAPK signaling in response to TGF-β1.

MKP-1 regulates the inflammatory activation of microglia against Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases leading to dementia in elderly people. Microglia-mediated neuroinflammation plays an important role in AD pathogenesis, so modulation of neuroinflammation has emerged as an essential therapeutic method to improve AD. The current study aims to investigate whether MKP-1 can regulate microglia phenotype and inflammatory factor release in AD and explore its possible mechanisms.

METHODS

Amyloid precursor protein/PS1 double transgenic mice and wild-type mice were selected to study the locations of microglia and amyloid-β (Aβ) plaques in different regions of mice brains. Changes in MKP-1 of microglia were detected using AD model mice and AD model cells. Changes in phenotype and the release of inflammatory factors within immortalized BV2 murine microglia were investigated by regulating the expression of MKP-1.

RESULTS

The distribution of microglia and Aβ plaques in the AD brain was region-specific. MKP-1 expression was downregulated in AD mice, and in vitro, with increasing Aβ concentrations, MKP-1 expression was reduced. MKP-1 over-expression increased M2 microglia but decreased M1 microglia accompanied by changes in inflammatory factors and inhibition of MKP-1 yielded the opposite result.

CONCLUSION

MKP-1 regulated microglia phenotype and inflammatory factor release in AD through modulation of the p38 signaling pathway.

The mTORC2 signaling network: targets and cross-talks

The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.

Genetic alterations in thyroid cancer mediating both resistance to BRAF inhibition and anaplastic transformation

A subset of thyroid cancers present at advanced stage or with dedifferentiated histology and have limited response to standard therapy. Tumors harboring the BRAF V600E mutation may be treated with BRAF inhibitors; however, tumor response is often short lived due to multiple compensatory resistance mechanisms. One mode of resistance is the transition to an alternative cell state, which on rare occasions can correspond to tumor dedifferentiation. DNA sequencing and RNA expression profiling show that thyroid tumors that dedifferentiate after BRAF inhibition are enriched in known genetic alterations that mediate resistance to BRAF blockade, and may also drive tumor dedifferentiation, including mutations in the PI3K/AKT/MTOR (PIK3CA, MTOR), MAP/ERK (MET, NF2, NRAS, RASA1), SWI/SNF chromatin remodeling complex (ARID2, PBRM1), and JAK/STAT pathways (JAK1). Given these findings, recent investigations have evaluated the efficacy of dual-target therapies; however, continued lack of long-term tumor control illustrates the complex and multifactorial nature of these compensatory mechanisms. Transition to an immune-suppressed state is another correlate of BRAF inhibitor resistance and tumor dedifferentiation, suggesting a possible role for concurrent targeted therapy with immunotherapy. Investigations into combined targeted and immunotherapy are ongoing, but early results with checkpoint inhibitors, viral therapies, and CAR T-cells suggest enhanced anti-tumor immune activity with these combinations.

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.

Revisiting the Role of B-RAF Kinase as a Therapeutic Target in Melanoma

Malignant melanoma is the rarest but most aggressive and deadly skin cancer. Melanoma is the result of a malignant transformation of melanocytes, which leads to their uncontrolled proliferation. Mutations in the mitogen-activated protein kinase (MAPK) pathway, which are crucial for the control of cellular processes, such as apoptosis, division, growth, differentiation, and migration, are one of its most common causes. BRAF kinase, as one of the known targets of this pathway, has been known for many years as a prominent molecular target in melanoma therapy, and the following mini-review outlines the state-of-the-art knowledge regarding its structure, mutations and mechanisms.

Nanotechnology-mediated photodynamic therapy: Focus on overcoming tumor hypoxia

The oxygen level in the tumor is a critical marker that determines response to different treatments. Cancerous cells can adapt to hypoxia and low pH conditions within the tumor microenvironment (TME) to regulate tumor metabolism, proliferation, and promote tumor metastasis as well as angiogenesis, consequently leading to treatment failure and recurrence. In recent years, widespread attempts have been made to overcome tumor hypoxia through different methods, such as hyperbaric oxygen therapy (HBOT), hyperthermia, O2 carriers, artificial hemoglobin, oxygen generator hydrogels, and peroxide materials. While oxygen is found to be an essential agent to improve the treatment response of photodynamic therapy (PDT) and other cancer treatment modalities, the development of hypoxia within the tumor is highly associated with PDT failure. Recently, the use of nanoparticles has been a hot topic for researchers and exploited to overcome hypoxia through Oxygen-generating hydrogels, O2 nanocarriers, and O2 -generating nanoparticles. This review aimed to discuss the role of nanotechnology in tumor oxygenation and highlight the challenges, prospective, and recent advances in this area to improve PDT outcomes. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Fucoidan's Molecular Targets: A Comprehensive Review of Its Unique and Multiple Targets Accounting for Promising Bioactivities Supported by In Silico Studies

Fucoidan is a class of multifunctional polysaccharides derived from marine organisms. Its unique and diversified physicochemical and chemical properties have qualified them for potential and promising pharmacological uses in human diseases, including inflammation, tumors, immunity disorders, kidney diseases, and diabetes. Physicochemical and chemical properties are the main contributors to these bioactivities. The previous literature has attributed such activities to its ability to target key enzymes and receptors involved in potential disease pathways, either directly or indirectly, where the anionic sulfate ester groups are mainly involved in these interactions. These findings also confirm the advantageous pharmacological uses of sulfated versus non-sulfated polysaccharides. The current review shall highlight the molecular targets of fucoidans, especially enzymes, and the subsequent responses via either the upregulation or downregulation of mediators' expression in various tissue abnormalities. In addition, in silico studies will be applied to support the previous findings and show the significant contributors. The current review may help in understanding the molecular mechanisms of fucoidan. Also, the findings of this review may be utilized in the design of specific oligomers inspired by fucoidan with the purpose of treating life-threatening human diseases effectively.

Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

Metastatic dissemination of solid tumors, a leading cause of cancer-related mortality, underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis, chemoresistance, and the mechanistic backgrounds of individuals whose cancers are prone to migration. The most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase (MAPK) pathway, encompassing the RAS-RAF-MAPK kinase (MEK)-extracellular signal-related kinase (ERK) pathway. RAF kinase is a primary mediator of the MAPK pathway, responsible for the sequential activation of downstream targets, such as MEK and the transcription factor ERK, which control numerous cellular and physiological processes, including organism development, cell cycle control, cell proliferation and differentiation, cell survival, and death. Defects in this signaling cascade are associated with diseases such as cancer. RAF inhibitors (RAFi) combined with MEK blockers represent an FDA-approved therapeutic strategy for numerous RAF-mutant cancers, including melanoma, non-small cell lung carcinoma, and thyroid cancer. However, the development of therapy resistance by cancer cells remains an important barrier. Autophagy, an intracellular lysosome-dependent catabolic recycling process, plays a critical role in the development of RAFi resistance in cancer. Thus, targeting RAF and autophagy could be novel treatment strategies for RAF-mutant cancers. In this review, we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and RAFi-resistance. Furthermore, we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic profiles. Additionally, this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

A guide to ERK dynamics, part 1: mechanisms and models

Extracellular signal-regulated kinase (ERK) has long been studied as a key driver of both essential cellular processes and disease. A persistent question has been how this single pathway is able to direct multiple cell behaviors, including growth, proliferation, and death. Modern biosensor studies have revealed that the temporal pattern of ERK activity is highly variable and heterogeneous, and critically, that these dynamic differences modulate cell fate. This two-part review discusses the current understanding of dynamic activity in the ERK pathway, how it regulates cellular decisions, and how these cell fates lead to tissue regulation and pathology. In part 1, we cover the optogenetic and live-cell imaging technologies that first revealed the dynamic nature of ERK, as well as current challenges in biosensor data analysis. We also discuss advances in mathematical models for the mechanisms of ERK dynamics, including receptor-level regulation, negative feedback, cooperativity, and paracrine signaling. While hurdles still remain, it is clear that higher temporal and spatial resolution provide mechanistic insights into pathway circuitry. Exciting new algorithms and advanced computational tools enable quantitative measurements of single-cell ERK activation, which in turn inform better models of pathway behavior. However, the fact that current models still cannot fully recapitulate the diversity of ERK responses calls for a deeper understanding of network structure and signal transduction in general.

Sphingosine-1-phosphate receptor 3 is a non-hormonal target to counteract endometriosis-associated fibrosis

OBJECTIVE

To study the molecular mechanisms responsible for fibrosis in endometriosis by investigating whether the protein expression levels of sphingosine-1-phosphate receptor 3 (S1PR3), one of the five specific receptors of the bioactive sphingolipid sphingosine-1-phosphate (S1P), correlate with fibrosis extent in endometriotic lesions and which are the cellular mechanisms involved in this process.

DESIGN

Case-control laboratory study and cultured endometriotic cells.

SETTING

University research institute and university hospital.

PATIENT(S)

A total of 33 women, with and without endometriosis, were included in the study.

INTERVENTIONS(S)

Endometriotic lesions were obtained from women with endometriosis (ovarian endometrioma, n = 8; deep infiltrating endometriosis, n = 15; [urological n = 5, gastrointestinal n = 6, and posterior n = 4]) and control endometrium from healthy women, n = 10, by means of laparoscopic and hysteroscopic surgery. The expression of S1PR3 was evaluated using immunohistochemistry and the extent of fibrosis was assessed using Masson's trichrome staining. Human-cultured epithelial endometriotic 12Z cells were used to evaluate the mechanisms involved in the profibrotic effect of S1PR3 activation.

MAIN OUTCOME MEASURE(S)

The expression of S1PR3 in endometriotic lesions is positively correlated with endometriosis-associated fibrosis. In addition, S1P induced epithelial-mesenchymal transition (EMT) and fibrosis in epithelial endometriotic cells. Using RNA interference and pharmacological approaches, the profibrotic effect of S1P was shown to rely on S1PR3, thus unveiling the molecular mechanism implicated in the profibrotic action of the bioactive sphingolipid.

RESULT(S)

The protein expression levels of S1PR3 were significantly augmented in the glandular sections of endometrioma and deep infiltrating endometriosis of different localizations with respect to the control endometrium and positively correlated with the extent of fibrosis. Sphingosine-1-phosphate was shown to have a crucial role in the onset of fibrosis in epithelial endometriotic cells, stimulating the expression of EMT and fibrotic markers. Genetic approaches have highlighted that S1PR3 mediates the fibrotic effect of S1P. Downstream of S1PR3, ezrin and extracellular-signal-regulated kinases 1 and 2 signaling were found to be critically implicated in the EMT and fibrosis elicited by S1P.

CONCLUSION(S)

Sphingosine-1-phosphate receptor 3 may represent a possible innovative pharmacological target for endometriosis.

Research on the Pathogenesis of Cognitive and Neurofunctional Impairments in Patients with Noonan Syndrome: The Role of Rat Sarcoma-Mitogen Activated Protein Kinase Signaling Pathway Gene Disturbances

Noonan syndrome (NS) is one of the most common genetic conditions inherited mostly in an autosomal dominant manner with vast heterogeneity in clinical and genetic features. Patients with NS might have speech disturbances, memory and attention deficits, limitations in daily functioning, and decreased overall intelligence. Here, 34 patients with Noonan syndrome and 23 healthy controls were enrolled in a study involving gray and white matter volume evaluation using voxel-based morphometry (VBM), white matter connectivity measurements using diffusion tensor imaging (DTI), and resting-state functional magnetic resonance imaging (rs-fMRI). Fractional anisotropy (FA) and mean diffusivity (MD) probability distributions were calculated. Cognitive abilities were assessed using the Stanford Binet Intelligence Scales. Reductions in white matter connectivity were detected using DTI in NS patients. The rs-fMRI revealed hyper-connectivity in NS patients between the sensorimotor network and language network and between the sensorimotor network and salience network in comparison to healthy controls. NS patients exhibited decreased verbal and nonverbal IQ compared to healthy controls. The assessment of the microstructural alterations of white matter as well as the resting-state functional connectivity (rsFC) analysis in patients with NS may shed light on the mechanisms responsible for cognitive and neurofunctional impairments.

Gemcitabine resistance in non-small cell lung cancer is mediated through activation of the PI3K/AKT/NF-κB pathway and suppression of ERK signaling by reactive oxygen species

Lung cancer is one of the most common cancers in the world. Chemotherapy is a standard clinical treatment. However, tumor cells often develop multidrug resistance after chemotherapy, an inevitable bottleneck in cancer treatment. Therefore, this study used gemcitabine-resistant (GEM-R) CL1-0 lung cancer cells. First, we used flow cytometry and western blot analysis to examine differences in performance between resistant and parental cells. The results showed that compared with parental cells, GEM-R CL1-0 cells significantly enhanced the activation of the AKT pathway, which promoted survival and growth, and decreased the activation of the reactive oxygen species-extracellular signal-regulated kinase (ROS)-ERK pathway. Next, the AKT and ERK pathways' role in tumor growth was further explored in vivo using a xenograft model. The results showed that enhancing AKT and inhibiting ERK activation reduced GEM-induced inhibition of tumor growth. Finally, combining the above results, we found that GEM-R CL1-0 cells showed reduced sensitivity to GEM by activating the phosphatidylinositol 3-kinase/AKT/NF-kB pathway and inhibiting the ROS-ERK pathway leading to resistance against GEM. Therefore, the AKT and ERK pathways are potential targets for improving the sensitivity of cancer cells to anticancer drugs.

Linear motif specificity in signaling through p38α and ERK2 mitogen-activated protein kinases

Mitogen-activated protein kinase (MAPK) cascades are essential for eukaryotic cells to integrate and respond to diverse stimuli. Maintaining specificity in signaling through MAPK networks is key to coupling distinct inputs to appropriate cellular responses. Docking sites-short linear motifs found in MAPK substrates, regulators, and scaffolds-can promote signaling specificity through selective interactions, but how they do so remains unresolved. Here, we screened a proteomic library for sequences interacting with the MAPKs extracellular signal-regulated kinase 2 (ERK2) and p38α, identifying selective and promiscuous docking motifs. Sequences specific for p38α had high net charge and lysine content, and selective binding depended on a pair of acidic residues unique to the p38α docking interface. Finally, we validated a set of full-length proteins harboring docking sites selected in our screens to be authentic MAPK interactors and substrates. This study identifies features that help define MAPK signaling networks and explains how specific docking motifs promote signaling integrity.

Cell-cycle arrest and mitochondria-dependent apoptosis induction in T-47D cells by the capsular polysaccharide from the marine bacterium Kangiella japonica KMM 3897

In this study, we reported the in vitro mechanisms of antiproliferative activity of capsular polysaccharide derived from marine Gram-negative bacteria Kangiella japonica KMM 3897 in human breast сarcinoma T-47D cells. Flow cytometric and Western blot analysis revealed that capsular polysaccharide effectively suppressed T-47D cell proliferation by inducing G0/G1 phase arrest and mitochondrial-dependent apoptosis. Moreover, polysaccharide influenced the ERK1/2 and p38 signaling pathways. The results of this study would enrich our understanding of the molecular mechanism of the anti-cancer activity of sulfated polysaccharides from marine Gram-negative bacteria.

Design, Synthesis, and Antitumor Activity Evaluation of Proteolysis-Targeting Chimeras as Degraders of Extracellular Signal-Regulated Kinases 1/2

Inhibition of the extracellular signal-regulated kinases 1/2 (ERK1/2) alone or in combination with other targets has emerged as a promising treatment strategy for a variety of human tumors. In addition to the development of inhibitors, the development of ERK1/2 degraders is an alternative approach to decrease its activity. We synthesized proteolysis-targeting chimeras (PROTACs) as effective ERK1/2 degraders, among which B1-10J showed high degradative activity, with DC50 of 102 nM and cytotoxic IC50 of 2.2 μM against HCT116 cells. Moreover, B1-10J dose-dependently inhibited tumor cell migration. Xenograft experiments in nude mice demonstrated that B1-10J inhibited HCT116 tumor cell growth and achieved significant regression of tumors at a daily dose of 25 mg/kg.

Cooperativity and oscillations: Regulatory mechanisms of K-Ras nanoclusters

K-Ras nanoclusters (NCs) concentrate all required molecules belonging to the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway in a small area where signaling events take place, increasing efficiency and specificity of signaling. Such nanostructures are characterized by controlled sizes and lifetimes distributions, but there is a poor understanding of the mechanisms involved in their dynamics of growth/decay. Here, a minimum computational model is presented to analyze the behavior of K-Ras NCs as cooperative dynamic structures that self-regulate their growth and decay according to their size. Indeed, the proposed model reveals that the growth and the local production of a K-Ras nanocluster depend positively on its actual size, whilst its lifetime is inversely proportional to the root of its size. The cooperative binding between the structural constituents of the NC (K-Ras proteins) induces oscillations in the size distributions of K-Ras NCs allowing them to range within controlled values, regulating the growth/decay dynamics of these NCs. Thereby, the size of a K-Ras NC is proposed as a key factor to regulate cell signaling, opening a range of possibilities to develop strategies for use in chronic diseases and cancer.

Cutaneous Melanoma: A Review of Multifactorial Pathogenesis, Immunohistochemistry, and Emerging Biomarkers for Early Detection and Management

Cutaneous melanoma (CM) is an increasingly significant public health concern. Due to alarming mortality rates and escalating incidence, it is crucial to understand its etiology and identify emerging biomarkers for improved diagnosis and treatment strategies. This review aims to provide a comprehensive overview of the multifactorial etiology of CM, underscore the importance of early detection, discuss the molecular mechanisms behind melanoma development and progression, and shed light on the role of the potential biomarkers in diagnosis and treatment. The pathogenesis of CM involves a complex interplay of genetic predispositions and environmental exposures, ultraviolet radiation exposure being the predominant environmental risk factor. The emergence of new biomarkers, such as novel immunohistochemical markers, gene mutation analysis, microRNA, and exosome protein expressions, holds promise for improved early detection, and prognostic and personalized therapeutic strategies.

Optical Approaches for Investigating Neuromodulation and G Protein-Coupled Receptor Signaling

Despite the fact that roughly 40% of all US Food and Drug Administration (FDA)-approved pharmacological therapeutics target G protein-coupled receptors (GPCRs), there remains a gap in our understanding of the physiologic and functional role of these receptors at the systems level. Although heterologous expression systems and in vitro assays have revealed a tremendous amount about GPCR signaling cascades, how these cascades interact across cell types, tissues, and organ systems remains obscure. Classic behavioral pharmacology experiments lack both the temporal and spatial resolution to resolve these long-standing issues. Over the past half century, there has been a concerted effort toward the development of optical tools for understanding GPCR signaling. From initial ligand uncaging approaches to more recent development of optogenetic techniques, these strategies have allowed researchers to probe longstanding questions in GPCR pharmacology both in vivo and in vitro. These tools have been employed across biologic systems and have allowed for interrogation of everything from specific intramolecular events to pharmacology at the systems level in a spatiotemporally specific manner. In this review, we present a historical perspective on the motivation behind and development of a variety of optical toolkits that have been generated to probe GPCR signaling. Here we highlight how these tools have been used in vivo to uncover the functional role of distinct populations of GPCRs and their signaling cascades at a systems level. SIGNIFICANCE STATEMENT: G protein-coupled receptors (GPCRs) remain one of the most targeted classes of proteins for pharmaceutical intervention, yet we still have a limited understanding of how their unique signaling cascades effect physiology and behavior at the systems level. In this review, we discuss a vast array of optical techniques that have been devised to probe GPCR signaling both in vitro and in vivo.

Turnover and bypass of p21-activated kinase during Cdc42-dependent MAPK signaling in yeast

Mitogen-activated protein kinase (MAPK) pathways regulate multiple cellular behaviors, including the response to stress and cell differentiation, and are highly conserved across eukaryotes. MAPK pathways can be activated by the interaction between the small GTPase Cdc42p and the p21-activated kinase (Ste20p in yeast). By studying MAPK pathway regulation in yeast, we recently found that the active conformation of Cdc42p is regulated by turnover, which impacts the activity of the pathway that regulates filamentous growth (fMAPK). Here, we show that Ste20p is regulated in a similar manner and is turned over by the 26S proteasome. This turnover did not occur when Ste20p was bound to Cdc42p, which presumably stabilized the protein to sustain MAPK pathway signaling. Although Ste20p is a major component of the fMAPK pathway, genetic approaches here identified a Ste20p-independent branch of signaling. Ste20p-independent signaling partially required the fMAPK pathway scaffold and Cdc42p-interacting protein, Bem4p, while Ste20p-dependent signaling required the 14-3-3 proteins, Bmh1p and Bmh2p. Interestingly, Ste20p-independent signaling was inhibited by one of the GTPase-activating proteins for Cdc42p, Rga1p, which unexpectedly dampened basal but not active fMAPK pathway activity. These new regulatory features of the Rho GTPase and p21-activated kinase module may extend to related pathways in other systems.

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.

Photodynamic reactions using high-intensity red LED promotes gingival wound healing by ROS induction

Photodynamic therapy is a treatment that combines a light source with a photosensitizer. LEDs have attracted considerable attention in clinical dentistry because they are inexpensive and safe to use. Although the interaction between photosensitizers and LEDs in dental practice is effective for treating periodontal disease by killing periodontopathic bacteria, little is known about the effects of LEDs on human gingival fibroblasts (HGnFs), which play an important role in gingival wound healing. In this study, we investigated the effects of high-intensity red LED irradiation on HGnFs after the addition of methylene blue (MB), one of the least harmful photosensitizers, on wound healing and reactive oxygen species (ROS) production induced by photodynamic reactions. We found that irradiation of MB with high-intensity red LED at controlled energy levels promoted cell proliferation, migration, and production of wound healing factors. Furthermore, ROS production by a photodynamic reaction enabled the translocation of phosphorylated Grb2-associated binder-1, activating Extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase signals. Our findings suggest that proper control of ROS production has a beneficial effect on gingival fibroblasts, which constitute periodontal tissue, from the perspective of gingival wound healing.

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.

Inflammation-related signaling pathways in tendinopathy

Tendon is a connective tissue that produces movement by transmitting the force produced by muscle contraction to the bones. Most tendinopathy is caused by prolonged overloading of the tendon, leading to degenerative disease of the tendon. When overloaded, the oxygen demand of tenocytes increases, and the tendon structure is special and lacks blood supply, which makes it easier to form an oxygen-deficient environment in tenocytes. The production of reactive oxygen species due to hypoxia causes elevation of inflammatory markers in the tendon, including PGE2, IL-1β, and TNF-α. In the process of tendon healing, inflammation is also a necessary stage. The inflammatory environment formed by cytokines and various immune cells play an important role in the clearance of necrotic material, the proliferation of tenocytes, and the production of collagen fibers. However, excessive inflammation can lead to tendon adhesions and hinder tendon healing. Some important and diverse biological functions of the body originate from intercellular signal transduction, among which cytokine mediation is an important way of signal transduction. In particular, NF-κB, NLRP3, p38/MAPK, and signal transducer and activator of transcription 3, four common signaling pathways in tendinopathy inflammatory response, play a crucial role in the regulation and transcription of inflammatory factors. Therefore, summarizing the specific mechanisms of inflammatory signaling pathways in tendinopathy is of great significance for an in-depth understanding of the inflammatory response process and exploring how to inhibit the harmful part of the inflammatory response and promote the beneficial part to improve the healing effect of the tendon.

MKP1 promotes nonalcoholic steatohepatitis by suppressing AMPK activity through LKB1 nuclear retention

Nonalcoholic steatohepatitis (NASH) is triggered by hepatocyte death through activation of caspase 6, as a result of decreased adenosine monophosphate (AMP)-activated protein kinase-alpha (AMPKα) activity. Increased hepatocellular death promotes inflammation which drives hepatic fibrosis. We show that the nuclear-localized mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP1) is upregulated in NASH patients and in NASH diet fed male mice. The focus of this work is to investigate whether and how MKP1 is involved in the development of NASH. Under NASH conditions increased oxidative stress, induces MKP1 expression leading to nuclear p38 MAPK dephosphorylation and decreases liver kinase B1 (LKB1) phosphorylation at a site required to promote LKB1 nuclear exit. Hepatic deletion of MKP1 in NASH diet fed male mice releases nuclear LKB1 into the cytoplasm to activate AMPKα and prevents hepatocellular death, inflammation and NASH. Hence, nuclear-localized MKP1-p38 MAPK-LKB1 signaling is required to suppress AMPKα which triggers hepatocyte death and the development of NASH.

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.

Eucalyptol induces osteoblast differentiation through ERK phosphorylation in vitro and in vivo

Eucalyptol (EU) is monoterpene oxide that is the main component of the essential oil extracted from aromatic plants such as Eucalyptus globules. EU has therapeutic effects such as antibacterial, anti-inflammatory and antioxidant in chronic diseases including inflammation disorder, respiratory disease, and diabetic disease. However, the effects of EU on osteoblast differentiation and bone diseases such as osteoporosis have not been studied. The present study investigated the effects of EU on osteoblast differentiation and bone formation. EU induces mRNA and protein expression of osteogenic genes in osteoblast cell line MC3T3-E1 and primary calvarial osteoblasts. EU also promoted alkaline phosphatase (ALP) activity and mineralization. Here, the osteoblast differentiation effect of EU is completely reversed by ERK inhibitor. These results demonstrate that osteoblast differentiation effect of EU is mediated by ERK phosphorylation. The efficacy of EU on bone formation was investigated using surgical bone loss-induced animal models. EU dose-dependently promoted bone regeneration in zebrafish caudal fin rays. In the case of ovariectomized mice, EU increased ERK phosphorylation and ameliorated bone loss of femurs. These results indicate that EU ameliorates bone loss by promoting osteoblast differentiation through ERK phosphorylation. We suggest that EU, plant-derived monoterpenoid, may be useful for preventing bone loss. KEY MESSAGES: Eucalyptol (EU) increases osteoblast differentiation in pre-osteoblasts. EU up-regulates the osteogenic genes expression via ERK phosphorylation. EU promotes bone regeneration in partially amputated zebrafish fin rays. Oral administration of EU improves ovariectomy-induced bone loss and increases ERK phosphorylation.

The regulatory roles of Fasciola hepatica GSTO1 protein in inflammatory cytokine expression and apoptosis in murine macrophages

Fascioliasis, a global zoonotic parasitic disease, is mainly caused by Fasciola hepatica (F. hepatica) parasitizing in the livers of hosts, mainly humans and herbivores. Glutathione S-transferase (GST) is one of the important excretory- secretory products (ESPs) from F. hepatica, however, the regulatory roles of its Omega subtype in the immunomodulatory effects remain unknown. Here, we expressed F. hepatica recombinant GSTO1 protein (rGSTO1) in Pichia pastoris and analyzed its antioxidant properties. Then, the interaction between F. hepatica rGSTO1 and RAW264.7 macrophages and its effects on inflammatory responses and cell apoptosis were further explored. The results revealed that GSTO1 of F. hepatica owned the potent ability to resist oxidative stress. F. hepatica rGSTO1 could interact with RAW264.7 macrophages and inhibit its cell viability, furthermore, it may suppress the production of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, but promote the expression of anti-inflammatory cytokine IL-10. In addition, F. hepatica rGSTO1 may down-regulate the ratio of Bcl-2/Bax, and increase the expression of pro-apoptotic protein caspase-3, thereby eliciting the apoptosis of macrophages. Notably, F. hepatica rGSTO1 inhibited the activation of nuclear factor-κB (NF-κB) and mitogen‑activated protein kinases (MAPKs p38, ERK and JNK) pathways in LPS-activated RAW264.7 cells, exerting potent modulatory effects on macrophages. These findings suggested that F. hepatica GSTO1 can modulate the host immune response, which provided new insights into the immune evasion mechanism of F. hepatica infection in host.

Identification and biochemical characterization of small molecule inhibitors of ERK2 that target the D-recruitment site

Extracellular signal-regulated kinase (ERK) is the culmination of a mitogen-activated protein kinase cascade that regulates cellular processes like proliferation, migration, and survival. Consequently, abnormal ERK signaling often plays a role in the tumorigenesis and metastasis of numerous cancers. ERK inhibition is a sought-after treatment for cancers, especially since clinically approved drugs that target signaling upstream of ERK often induce acquired resistance. Furthermore, the ERK2 isoform may have a differential role in various cancers from the other canonical isoform, ERK1. We demonstrate that small molecules can inhibit ERK2 catalytic and noncatalytic functions by binding to the D-recruitment site (DRS), a protein-protein interaction site distal to the enzyme active site. Using a fluorescence anisotropy-based high-throughput screening, we identify compounds that bind to the DRS and exhibit dose-dependent inhibition of ERK2 activity and ERK2 phosphorylation. We characterize the dose-dependent potency of ERK2 inhibitors using fluorescence anisotropy-based binding assays, fluorescence-based ERK2 substrate phosphorylation assays, and in vitro ERK2 activation assays. In our example, the binding of a DRS inhibitor can be prevented by mutating the DRS residue Cys-159 to serine, indicating that this residue is essential for the interaction. Resulting inhibitors from this process can be assessed in cellular and in vivo experiments for inhibition of ERK signaling and can be evaluated as potential cancer drugs.

Mitogen-activated protein kinase (MAPK) cascades-A yeast perspective

Discovery of the class of protein kinase now dubbed a mitogen (or messenger)-activated protein kinase (MAPK) is an illustrative example of how disparate lines of investigation can converge and reveal an enzyme family universally conserved among eukaryotes, from single-celled microbes to humans. Moreover, elucidation of the circuitry controlling MAPK function defined a now overarching principle in enzyme regulation-the concept of an activation cascade mediated by sequential phosphorylation events. Particularly ground-breaking for this field of exploration were the contributions of genetic approaches conducted using several model organisms, but especially the budding yeast Saccharomyces cerevisiae. Notably, examination of how haploid yeast cells respond to their secreted peptide mating pheromones was crucial in pinpointing genes encoding MAPKs and their upstream activators. Fully contemporaneous biochemical analysis of the activities elicited upon stimulation of mammalian cells by insulin and other growth- and differentiation-inducing factors lead eventually to the demonstration that components homologous to those in yeast were involved. Continued studies of these pathways in yeast were integral to other foundational discoveries in MAPK signaling, including the roles of tethering, scaffolding and docking interactions.

Modulating p38 MAPK signaling by proteostasis mechanisms supports tissue integrity during growth and aging

The conserved p38 MAPK family is activated by phosphorylation during stress responses and inactivated by phosphatases. C. elegans PMK-1 p38 MAPK initiates innate immune responses and blocks development when hyperactivated. Here we show that PMK-1 signaling is enhanced during early aging by modulating the stoichiometry of non-phospho-PMK-1 to promote tissue integrity and longevity. Loss of pmk-1 function accelerates progressive declines in neuronal integrity and lysosome function compromising longevity which has both cell autonomous and cell non-autonomous contributions. CED-3 caspase cleavage limits phosphorylated PMK-1. Enhancing p38 signaling with caspase cleavage-resistant PMK-1 protects lysosomal and neuronal integrity extending a youthful phase. PMK-1 works through a complex transcriptional program to regulate lysosome formation. During early aging, the absolute phospho-p38 amount is maintained but the reservoir of non-phospho-p38 diminishes to enhance signaling without hyperactivation. Our findings show that modulating the stoichiometry of non-phospho-p38 dynamically supports tissue-homeostasis during aging without hyper-activation of stress response.

Pharmacological Potential of Betulin as a Multitarget Compound

Betulin is a natural triterpene, usually from birch bark, known for its potential wound-healing properties. Despite having a wide range of pharmacological targets, no studies have proposed betulin as a multitarget compound. Betulin has protective effects against cardiovascular and liver diseases, cancer, diabetes, oxidative stress, and inflammation. It reduces postprandial hyperglycemia by inhibiting α-amylase and α-glucosidase activity, combats tumor cells by inducing apoptosis and inhibiting metastatic proteins, and modulates chronic inflammation by blocking the expression of proinflammatory cytokines via modulation of the NFκB and MAPKs pathways. Given its potential to influence diverse biological networks with high target specificity, it can be hypothesized that betulin may eventually become a new lead for drug development because it can modify a variety of pharmacological targets. The summarized research revealed that the diverse beneficial effects of betulin in various diseases can be attributed, at least in part, to its multitarget anti-inflammatory activity. This review focuses on the natural sources, pharmacokinetics, pharmacological activity of betulin, and the multi-target effects of betulin on signaling pathways such as MAPK, NF-κB, and Nrf2, which are important regulators of the response to oxidative stress and inflammation in the body.

MKP1 promotes nonalcoholic steatohepatitis by suppressing AMPK activity through LKB1 nuclear retention

Nonalcoholic steatohepatitis (NASH) is triggered by hepatocyte death through activation of caspase 6, as a result of decreased adenosine monophosphate (AMP)-activated protein kinase-alpha (AMPKα) activity. Increased hepatocellular death promotes inflammation which drives hepatic fibrosis. We show that the nuclear-localized mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP1) is upregulated in NASH patients and in NASH diet fed mice. The focus of this work was to investigate whether and how MKP1 is involved in the development of NASH. Under NASH conditions increased oxidative stress, induces MKP1 expression leading to nuclear p38 MAPK dephosphorylation and decreased liver kinase B1 (LKB1) phosphorylation at a site required to promote LKB1 nuclear exit. Hepatic deletion of MKP1 in NASH diet fed mice released nuclear LKB1 into the cytoplasm to activate AMPKα and prevent hepatocellular death, inflammation and NASH. Hence, nuclear-localized MKP1-p38 MAPK-LKB1 signaling is required to suppress AMPKα which triggers hepatocyte death and the development of NASH.

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.

BRAF V600E Mutation of Non-Small Cell Lung Cancer in Korean Patients

Background and Objectives: BRAF mutational status in resected non-small cell lung cancer (NSCLC) in the Korean population is poorly understood. We explored BRAF (particularly BRAF V600E) mutational status among Korean patients with NSCLC. Materials and Methods: This study included 378 patients with resected primary NSCLC who were enrolled from January 2015 to December 2017. The authors obtained formalin-fixed paraffin-embedded (FFPE) tissue blocks and performed peptide nucleic acid (PNA)-clamping polymerase chain reaction (PCR) for detecting BRAF V600, real-time PCR for detecting BRAF V600E, and immunohistochemical analyses using the mutation-specific Ventana VE1 monoclonal antibody. For positive cases in any methods mentioned above, direct Sanger sequencing was additionally performed. Results: The PNA-clamping method revealed the BRAF V600 mutation in 5 (1.3%) of the 378 patients. Among these five patients, real-time PCR, direct Sanger sequencing detected BRAF V600E mutations in three (0.8%) patients. Thus, two cases showed differences in their PNA-clamping and the others. Direct Sanger sequencing of PNA-clamping PCR product was performed for two cases showing negative results on direct Sanger sequencing; both contained BRAF mutations other than V600E. All patients harboring BRAF mutations had adenocarcinomas, and all patients with V600E mutation exhibited minor micropapillary components. Conclusions: Despite the low incidence of the BRAF mutation among Korean patients with NSCLC, lung adenocarcinoma patients with micropapillary components should be prioritized in terms of BRAF mutation testing. Immunohistochemical staining using Ventana VE1 antibody may serve as a screening examination for BRAF V600E.

Differences in p38-STAT3-S100A11 signaling after the administration of aristolochic acid I and IVa may account for the disparity in their nephrotoxicity

BACKGROUND

The safety of herbs containing aristolochic acids (AAs) has become a widespread concern. Previous reports indicate that AAs are highly nephrotoxic and carcinogenic, although there are more than 170 analogues of aristolochic acid. Not all AAs have the same degree of nephrotoxicity or carcinogenicity. Previous studies have found that aristolochic acid IVa (AA-IVa), the principal component of AAs within members of the Aristolochiaceae family, especially Asarum, a commonly used herb in China, has essentially no significant nephrotoxicity. However, several studies, including ours, have shown that aristolochic acid I (AA-I) is clearly nephrotoxic.

PURPOSE

The focus of the study was to elucidate the molecular mechanism responsible for the difference in nephrotoxicity between the AA-I and AA-IVa.

STUDY DESIGN/METHOD

Mice were administered with AA-I or AA-IVa for 22 weeks through the oral route, followed by a 50-week recovery time. The kidney tissues of mice were extracted at the end of 22 weeks. Pathological examination and proteomic detection (tandem mass tagging (TMT) and phosphorylated proteomics) were performed on the kidney tissue to investigate the key signaling pathways and targets of AAs-induced renal interstitial fibrosis (RIF). The key signaling pathways and targets were verified by Western blot (WB), siRNA transfection, and luciferase assays.

RESULTS

AA-I caused severe nephrotoxicity, high mortality, and extensive RIF. However, the same AA-IVa dosage exhibited almost no nephrotoxicity and does not trigger RIF. The activation of the p38-STAT3-S100A11 signaling pathway and upregulated expression of α smooth muscle actin (α-SMA) and Bcl2-associated agonist of cell death (Bad) proteins could be the molecular mechanism underlying AA-I-induced nephrotoxicity. On the other hand, AA-IVa did not regulate the activation of the p38-STAT3-S100A11 signaling pathway and had relatively little effect on the expression of α-SMA and Bad. Consequently, the difference in the regulation of p38-STAT3-S100A11 pathway, α-SMA, and Bad proteins between AA-I and AA-IVa may be responsible for the divergence in their level of nephrotoxicity.

CONCLUSION

This is the first study to reveal the molecular mechanism underlying the difference in nephrotoxicity between AA-I and AA-IVa. Whether STAT3 is activated or not may be the key factor leading to the difference in nephrotoxicity between AA-I and AA-IVa.

Erk5 functions in modulation of zebrafish intestinal permeability

The intestine of zebrafish consists of mucosa, muscularis and serosa. Intestinal epithelial cells (IECs) act as a physical and biochemical barrier to protect against invasion by external commensal bacteria. Cell junction is one of the crucial basis of the barrier function. When cell junctions were disrupted, intestinal permeability would be naturally impeded. Extracellular signal-regulated kinase 5 (ERK5), belonging to the Mitogen-activated protein kinase (MAPK) family, is involved in the normal physiological development of the cardiovascular system and nervous system. But the role of erk5 in intestinal morphogenesis and intestinal function is yet to know. Here, we showed that knockout of the erk5 in zebrafish larvae resulted in intestinal wall hypoplasia, including the thinned intestinal wall, reduced intestinal folds, and disrupted cell junctions. In addition, the intestinal permeability assay demonstrated that knockout of erk5 resulted in increased intestinal permeability. All of these showed that erk5 plays an essential role in the maintenance of intestinal barrier function. Thus, our data indicate that erk5 is a critical effector in intestinal morphogenesis and intestinal function, and dysfunction of erk5 would lead to intestinal diseases.

TLR7 Agonists Modulate the Activation of Human Conjunctival Epithelial Cells Induced by IL-1β via the ERK1/2 Signaling Pathway

Conjunctival epithelia cells play an important role in the development of allergic reactions. TLR7 agonists have been shown in studies to increase the body's immunological tolerance by controlling the proportion of Th1/Th2 cells, although it is still unknown what impact this has on conjunctival epithelial cells. In this study, we examined the effect of TLR7 agonists on the inflammatory-activation of conjunctival epithelial cells induced by IL-1β. Quantitative PCR and ELISA analysis confirmed that TLR7 agonists could impair the proinflammatory cytokines released by the epithelia cells, whereas pro-inflammatory cytokines led to subsequent reactive oxygen species and neutrophil chemotaxis. Phosphorylation analysis and nucleocytoplasmic separation further confirmed that TLR7 agonists inhibit IL-1β-induced epithelia cells activation and ATP depletion via modulating the cytoplasmic residence of ERK1/2. Our finding indicated that TLR7 of conjunctival epithelia cells could be as a potent anti-inflammatory target for the ocular surface. And TLR7 agonists may become potential new drug for the treatment of allergic conjunctivitis.

T cells: an emerging cast of roles in bipolar disorder

Bipolar disorder (BD) is a distinctly heterogeneous and multifactorial disorder with a high individual and social burden. Immune pathway dysregulation is an important pathophysiological feature of BD. Recent studies have suggested a potential role for T lymphocytes in the pathogenesis of BD. Therefore, greater insight into T lymphocytes' functioning in patients with BD is essential. In this narrative review, we describe the presence of an imbalance in the ratio and altered function of T lymphocyte subsets in BD patients, mainly in T helper (Th) 1, Th2, Th17 cells and regulatory T cells, and alterations in hormones, intracellular signaling, and microbiomes may be potential causes. Abnormal T cell presence explains the elevated rates of comorbid inflammatory illnesses in the BD population. We also update the findings on T cell-targeting drugs as potentially immunomodulatory therapeutic agents for BD disease in addition to classical mood stabilizers (lithium, valproic acid). In conclusion, an imbalance in T lymphocyte subpopulation ratios and altered function may be involved in the development of BD, and maintaining T cell immune homeostasis may provide an overall therapeutic benefit.