Search

Extracellular signal-regulated protein kinase 5 (Erk5), a member of the mitogen-activated protein kinase (MAPK) family, is ubiquitously expressed in all eukaryotic cells and is implicated in the various mitotic processes such as cell survival, proliferation, migration, and differentiation. However, the potential functional roles of Erk5 in oocyte meiosis have not been fully determined. In this study, we document that ERK5 participates in the meiotic maturation of mouse oocytes by regulating the spindle assembly to ensure the meiotic progression. We unexpectedly found that phosphorylated ERK5 was localized in the spindle pole region at metaphase I and II stages by immunostaining analysis. Inhibition of ERK5 activity using its specific inhibitor XMD8-92 dramatically reduced the incidence of first polar body extrusion. In addition, inhibition of ERK5 evoked the spindle assembly checkpoint to arrest oocytes at metaphase I stage by impairing the spindle assembly, chromosome alignment and kinetochore-microtubule attachment. Mechanically, over-strengthened microtubule stability was shown to disrupt the microtubule dynamics and thus compromise the spindle assembly in ERK5-inhibited oocytes. Conversely, overexpression of ERK5 caused decreased level of acetylated α-tubulin and spindle defects. Collectively, we conclude that ERK5 plays an important role in the oocyte meiotic maturation by regulating microtubule dynamics and spindle assembly. • Phosphorylated ERK5 was localized in the spindle pole region at metaphase I and II stages in oocytes. • Inhibition of ERK5 evoked the spindle assembly checkpoint to arrest oocytes at metaphase I stage. • Over-strengthened microtubule stability was shown to disrupt the microtubule dynamics in ERK5-inhibited oocytes. • Overexpression of ERK5 causes decreased level of acetylated α-tubulin and spindle defects. [ABSTRACT FROM AUTHOR]

Background and Purpose: The AMP‐activated protein kinase (AMPK) signalling pathway is a desirable target for various cardiovascular diseases (CVD), while the involvement of AMPK‐mediated specific downstream pathways and effective interventions in hyperlipidaemia‐induced endothelial dysfunction remain largely unknown. Herein, we aim to identify an effective AMPK activator and to explore its efficacy and mechanism against endothelial dysfunction. Experimental Approach: Molecular docking technique was adopted to screen for the potent AMPK activator among 11 most common rare ginsenosides. In vivo, poloxamer 407 (P407) was used to induce acute hyperlipidaemia in C57BL/6J mice. In vitro, palmitic acid (PA) was used to induce lipid toxicity in HAEC cells. Key Results: We discovered the strongest binding of ginsenoside Rh4 to AMPKα1 and confirmed the action of Rh4 on AMPK activation. Rh4 effectively attenuated hyperlipidaemia‐related endothelial injury and oxidative stress both in vivo and in vitro and restored cell viability, mitochondrial membrane potential and mitochondrial oxygen consumption rate in HAEC cells. Mechanistically, Rh4 bound to AMPKα1 and simultaneously up‐regulated AKT/eNOS‐mediated NO release, promoted PGC‐1α‐mediated mitochondrial biogenesis and inhibited P38 MAPK/NFκB‐mediated inflammatory responses in both P407‐treated mice and PA‐treated HAEC cells. The AMPK inhibitor Compound C treatment completely abrogated the regulation of Rh4 on the above pathways and weakened the lowering effect of Rh4 on endothelial impairment markers, suggesting that the beneficial effects of Rh4 are AMPK dependent. Conclusion and Implications: Rh4 may serve as a novel AMPK activator to protect against hyperlipidaemia‐induced endothelial dysfunction, providing new insights into the prevention and treatment of endothelial injury‐associated CVD. [ABSTRACT FROM AUTHOR]

Mangiferin is a bioactive substance present in high concentration in mangoes and also in some other fruits. Owing to its potential as a chemopreventive and chemotherapeutic agent against several types of cancer, this unique, significant, and well‐researched polyphenol has received a lot of attention recently. It possesses the ability to treat cancers, including rectal cancer, prostate cancer, ovarian cancer, leukemia, gastric cancer, liver cancer, chronic pancreatitis, and lung cancer. It can control/regulate multiple key signaling pathways, such as signal transducer and activator of transcription 3 (STAT3), second mitochondria‐derived activator of caspases/direct inhibitor of apoptosis (IAP)‐binding protein with low propidium iodide (pl) (Smac/DIABLO) nuclear factor kappa B (NF‐κB), phosphatidylinositol 3 kinase/protein 3 kinase (PI3K/Akt), transforming growth factor beta/suppressor of mothers against decapentaplegic (TGF‐β/SMAD), c‐jun N‐terminal kinase/p38 mitogen‐activated protein kinase (JNK/p38‐MAPK), and phosphor‐I kappa B kinase (p‐IκB), which are crucial to the development of cancers. By triggering apoptotic signals and halting the advancement of the cell cycle, it can also prevent some cancer cell types from proliferating and developing. It has been revealed that mangiferin targets a variety of adhesion molecules, cytokines, pro‐inflammatory transcription factors, kinases, chemokines, growth factors, and cell‐cycle proteins. By means of preventing the onset, advancement, and metastasis of cancer, these targets may mediate the chemopreventive and therapeutic effects of mangiferin. Mangiferin has confirmed potential benefits in lung, cervical, breast, brain, and prostate cancers as well as leukemia whether administered alone or in combination with recognized anticancer compounds. More clinical trials and research investigations are required to completely unleash the potential of mangiferin, which may lower the risk of cancer onset and act as a preventive and therapeutic alternative for a number of cancers. [ABSTRACT FROM AUTHOR]

ABSTRACT Bacteria adapt the biosynthesis of their envelopes to specific growth conditions and prevailing stress factors. Peptidoglycan (PG) is the major component of the cell wall in Gram‐positive bacteria, where PASTA kinases play a central role in PG biosynthesis regulation. Despite their importance for growth, cell division and antibiotic resistance, the mechanisms of PASTA kinase activation are not fully understood. ReoM, a recently discovered cytosolic phosphoprotein, is one of the main substrates of the PASTA kinase PrkA in the Gram‐positive human pathogen Listeria monocytogenes. Depending on its phosphorylation, ReoM controls proteolytic stability of MurA, the first enzyme in the PG biosynthesis pathway. The late cell division protein GpsB has been implicated in PASTA kinase signalling. Consistently, we show that L. monocytogenes prkA and gpsB mutants phenocopied each other. Analysis of in vivo ReoM phosphorylation confirmed GpsB as an activator of PrkA leading to the description of structural features in GpsB that are important for kinase activation. We further show that ReoM phosphorylation is growth phase‐dependent and that this kinetic is reliant on the protein phosphatase PrpC. ReoM phosphorylation was inhibited in mutants with defects in MurA degradation, leading to the discovery that MurA overexpression prevented ReoM phosphorylation. Overexpressed MurA must be able to bind its substrates and interact with ReoM to exert this effect, but the extracellular PASTA domains of PrkA or MurJ flippases were not required. Our results indicate that intracellular signals control ReoM phosphorylation and extend current models describing the mechanisms of PASTA kinase activation. [ABSTRACT FROM AUTHOR]

Malignant ascites is commonly produced in advanced epithelial ovarian cancer (EOC) and serves as unique microenvironment for tumour cells. Acellular ascites fluid (AAF) is rich in signalling molecules and has been proposed to play a role in the induction of chemoresistance. Through in vitro testing of drug sensitivity and by assessing intracellular phosphorylation status in response to mono‐ and combination treatment of five EOC cell lines after incubation with AAFs derived from 20 different patients, we investigated the chemoresistance‐inducing potential of ascites. We show that the addition of AAFs to the culture media of EOC cell lines has the potential to induce resistance to standard‐of‐care drugs (SCDs). We also show that AAFs induce time‐ and concentration‐dependent activation of downstream signalling to signal transducer and activator of transcription 3 (STAT3), and concomitantly altered phosphorylation of mitogen‐activated protein kinase kinase (MEK), phosphoinositide 3‐kinase (PI3K)–protein kinase B (AKT) and nuclear factor NF‐kappa‐B (NFκB). Antibodies targeting the interleukin‐6 receptor (IL6R) effectively blocked phosphorylation of STAT3 and STAT1. Treatments with SCDs were effective in reducing cell viability in only a third of 30 clinically relevant conditions examined, defined as combinations of drugs, different cell lines and AAFs. Combinations of SCDs and novel therapeutics such as trametinib, fludarabine or rapamycin were superior in another third. Notably, we could nominate effective treatment combinations in almost all conditions except in 4 out of 30 conditions, in which trametinib or fludarabine showed higher efficacy alone. Taken together, our study underscores the importance of the molecular characterisation of individual patients' AAFs and the impact on treatment resistance as providing clinically meaningful information for future precision treatment approaches in EOC. [ABSTRACT FROM AUTHOR]

The centromere, a chromosome locus defined by the histone H3-like protein centromeric protein A (CENP-A), promotes assembly of the kinetochore to bind microtubules during cell division. Centromere maintenance requires CENP-A to be actively replenished by dedicated protein machinery in the early G1 phase of the cell cycle to compensate for its dilution after DNA replication. Cyclin-dependent kinases (CDKs) limit CENP-A deposition to once per cell cycle and function as negative regulators outside of early G1. Antithetically, Polo-like kinase 1 (PLK1) promotes CENP-A deposition in early G1, but the molecular details of this process are still unknown. We reveal here a phosphorylation network that recruits PLK1 to the deposition machinery to control a conformational switch required for licensing the CENP-A deposition reaction. Our findings clarify how PLK1 contributes to the epigenetic maintenance of centromeres. [ABSTRACT FROM AUTHOR]

Human phosphoglycerate kinase 1(hPGK1) is a key glycolytic enzyme that regulates the balance between ADP and ATP concentrations inside the cell. Phosphorylation of hPGK1 at S203 and S256 has been associated with enzyme import from the cytosol to the mitochondria and the nucleus respectively. These changes in subcellular locations drive tumorigenesis and are likely associated with site‐specific changes in protein stability. In this work, we investigate the effects of site‐specific phosphorylation on thermal and kinetic stability and protein structural dynamics by hydrogen–deuterium exchange (HDX) and molecular dynamics (MD) simulations. We also investigate the binding of 3‐phosphoglycerate and Mg‐ADP using these approaches. We show that the phosphomimetic mutation S256D reduces hPGK1 kinetic stability by 50‐fold, with no effect of the mutation S203D. Calorimetric studies of ligand binding show a large decrease in affinity for Mg‐ADP in the S256D variant, whereas Mg‐ADP binding to the WT and S203D can be accurately investigated using protein kinetic stability and binding thermodynamic models. HDX and MD simulations confirmed the destabilization caused by the mutation S256D (with some long‐range effects on stability) and its reduced affinity for Mg‐ADP due to the strong destabilization of its binding site (particularly in the apo‐state). Our research provides evidence suggesting that modifications in protein stability could potentially enhance the translocation of hPGK1 to the nucleus in cancer. While the structural and energetic basis of its mitochondrial import remain unknown. [ABSTRACT FROM AUTHOR]

Transposable elements (TEs) are mobile genetic modules of viral derivation that have been co-opted to become modulators of mammalian gene expression. TEs are a major source of endogenous dsRNAs, signaling molecules able to coordinate inflammatory responses in various physiological processes. Here, we provide evidence for a positive involvement of TEs in inflammation-driven bone repair and mineralization. In newly fractured mice bone, we observed an early transient upregulation of repeats occurring concurrently with the initiation of the inflammatory stage. In human bone biopsies, analysis revealed a significant correlation between repeats expression, mechanical stress and bone mineral density. We investigated a potential link between LINE-1 (L1) expression and bone mineralization by delivering a synthetic L1 RNA to osteoporotic patient-derived mesenchymal stem cells and observed a dsRNA-triggered protein kinase (PKR)-mediated stress response that led to strongly increased mineralization. This response was associated with a strong and transient inflammation, accompanied by a global translation attenuation induced by eIF2α phosphorylation. We demonstrated that L1 transfection reshaped the secretory profile of osteoblasts, triggering a paracrine activity that stimulated the mineralization of recipient cells. Synopsis: Transposable elements (TEs) are selfish genetic modules that have, in certain contexts, evolved into modulators of mammalian gene expression. This study provides evidence for a role of TEs in promoting an inflammatory response that is required for bone repair and mineralization via dsRNA sensing-dependent PKR activation. In mice, TE expression is transiently upregulated shortly after a bone fracture concurrently with the onset of the inflammatory process. In humans, mechanically loaded bones upregulate TE expression, which correlates with local bone mineral density. Transfection with LINE-1 (L1) TE RNA stimulates mineralization activity in human osteoblasts in vitro. Cytoplasmic L1 RNA accumulation in differentiating osteoblasts triggers PKR-dependent translational shutdown, inflammation, and reshaping of the secretome. The secretome of L1 RNA-primed osteoblasts induces the mineralization activity of recipient osteoblasts. Bone fracture is associated with upregulation of transient transposable element RNA expression triggering bone mineralization via a paracrine, secretome mediated process. [ABSTRACT FROM AUTHOR]

Small molecular kinase inhibitors play a key role in modern cancer therapy. Protein kinases are essential mediators in the growth and progression of cancerous tumors, rendering involved kinases an increasingly important target for therapy. However, kinase inhibitors are almost insoluble in water because of their hydrophobic aromatic nature, often lowering their availability and pharmacological efficacy. Direct drug functionalization with polar groups represents a simple strategy to improve the drug solubility, availability, and performance. Here, we present a strategy to functionalize secondary amines with oligoethylene glycol (OEG) phosphate using a one‐pot synthesis in three exemplary kinase inhibiting drugs Ceritinib, Crizotinib, and Palbociclib. These OEG‐prodrug conjugates demonstrate superior solubility in water compared to the native drugs, with the solubility increasing up to 190‐fold. The kinase inhibition potential is only slightly decreased for the conjugates compared to the native drugs. We further show pH dependent hydrolysis of the OEG‐prodrugs which releases the native drug. We observe a slow release at pH 3, while the conjugates remain stable over 96 h under physiological conditions (pH 7.4). Using confocal microscopy, we verify improved cell uptake of the drug‐OEG conjugates into the cytoplasm of HeLa cells, further supporting our universal solubility approach. [ABSTRACT FROM AUTHOR]

Post-translational SUMOylation of nuclear and cytosolic proteins maintains homeostasis in eukaryotic cells and orchestrates programmed responses to changes in metabolic demand or extracellular stimuli. In excitable cells, SUMOylation tunes the biophysical properties and trafficking of ion channels. Ion channel SUMOylation status is determined by the opposing enzyme activities of SUMO ligases and deconjugases. Phosphorylation also plays a permissive role in SUMOylation. SUMO deconjugases have been identified for several ion channels, but their corresponding E3 ligases remain unknown. This study shows PIAS3, a.k.a. KChAP, is a bona fide SUMO E3 ligase for Kv4.2 and HCN2 channels in HEK cells, and endogenous Kv4.2 and Kv4.3 channels in cardiomyocytes. PIAS3-mediated SUMOylation at Kv4.2-K579 increases channel surface expression through a rab11a-dependent recycling mechanism. PKA phosphorylation at Kv4.2-S552 reduces the current mediated by Kv4 channels in HEK293 cells, cardiomyocytes, and neurons. This study shows PKA mediated phosphorylation blocks Kv4.2-K579 SUMOylation in HEK cells and cardiomyocytes. Together, these data identify PIAS3 as a key downstream mediator in signaling cascades that control ion channel surface expression. [ABSTRACT FROM AUTHOR]

Objective Methods Results Significance Early life seizures (ELS) are commonly associated with autism spectrum disorder (ASD); however, the exact role of ELS in the pathology is unknown. Prior studies have demonstrated social deficits, a core feature of ASD, following ELS; consequently, alterations in sensory modalities may contribute to the overall social deficits. Considering the speculated contribution of sensory deficit to social communication, we examined the developmental consequences of early postnatal kainic acid (KA)‐induced seizures on olfactory preference and neural markers in the olfactory bulb in both male and female Sprague Dawley rats.KA‐induced seizures or saline was administered. Rats were then exposed to a series of biologically relevant scents including male scent, female scent, nest scent, and phenylethylamine during the juvenile period and again during adulthood. Alterations in sensory modalities were expected to be expressed via abnormal preference for certain scents and/or production of abnormal ultrasonic vocalizations in response to scents. The olfactory bulbs were also assessed for the biologically relevant markers glial fibrillary acidic protein (GFAP) and calcium/calmodulin‐dependent protein kinase II (CAMKII).Our findings resulted in no significant differences in olfactory preference following ELS for juveniles or adults compared to controls. Similarly, there were no differences in GFAP expression or the ratio of phosphorylated CAMKII to CAMKII in either olfactory bulb. Interestingly, despite a lack of treatment differences, different scents were shown to elicit different responses in juvenile rats, yet these differences subsided in adulthood.Overall, the results of this study suggest that olfaction does not contribute to socialization deficit following ELS within the KA model. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To investigate the independent effects of irisin on insulin resistance (IR) in ovary of polycystic ovary syndrome (PCOS) and explore possible pathways.We established PCOS medel using Poretsky L's method, then PCOS rats were randomly divided into model group (M) and irisin group (I), and normal rats (N) were used as the control. Then rats in the group I were injected with recombinant irisin. Then the levels of circulating fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of IR (HOMA‐IR) and PI3K/AKT and MAPK/ERK pathways in each group were observed, as well as the effects of irisin on the levels of circulating HOMA‐IR and PI3K/AKT and MAPK/ERK pathways in ovary of PCOS rats were evaluated.Compared with normal group, levels of FBG, FINS, and HOMA‐IR of model group were significantly increased (p < 0.001, p < 0.001, and p < 0.001, respectively), levels of average optical density by IHC of p‐PI3K, PI3K, p‐AKT, and AKT (p = 0.015, p = 0.010, p = 0.005, and p = 0.009, respectively) and levels of mRNA concentration of PI3K and AKT (p = 0.001, and p = 0.005, respectively) were decreased, while the levels of average optical density of p‐ERK, ERK (p = 0.011, and p = 0.013, respectively) and level of mRNA concentration of ERK (p < 0.001) were increased in ovary. After irisin intervention, compared with model group, levels of FBG, FINS, and HOMA‐IR of rats in irisin group were significantly decreased (p = 0.001, p < 0.001, and p < 0.001, respectively), levels of average optical density by IHC of p‐PI3K, PI3K, p‐AKT, and AKT (p = 0.030, p = 0.024, p = 0.012, and p = 0.025, respectively) and levels of mRNA concentration of PI3K and AKT (p = 0.002, and p = 0.003, respectively) were significantly increased, while the levels of average optical density of p‐ERK, ERK (p = 0.004, and p = 0.026, respectively) and level of mRNA concentration of ERK (p = 0.001) were significantly decreased.Our study demonstrated that irisin could not only improve circulating insulin resistance, but may also improve ovarian IR through an increase in the activity of PI3K/AKT signaling and a decrease of MAPK/ERK signaling. [ABSTRACT FROM AUTHOR]

The repair of hierarchical osteochondral defects requires complex gradient reconstruction at different levels, with continuous‐gradient mineralization being crucial. Strategies for achieving continuous‐gradient mineralization have rarely been reported. Here, a continuous‐gradient mineralized hydrogel is prepared using simple gravitational osmosis of a ≈2 nm amorphous calcium phosphate nanocluster (ACPC) suspension into composite organic frameworks for osteochondral regeneration. During gravitational infiltration, ACPC underwent gradual mineralization, resulting in the spontaneous formation of hydroxyapatite (HAP). The continuous‐gradient mineralized hydrogel aligned closely with the normal osteochondral structure, thereby effectively promoting repair of the cartilage and subchondral bone. In the cartilage layer, organic compounds improved the oxidative stress environment induced by injury and complemented the extracellular matrix of the cartilage. In the subchondral bone layer, HAP from the continuously mineralized hydrogel induced intracellular calcium accumulation in mesenchymal stem cells (MSCs), activating calcium/calmodulin‐dependent protein kinase 2 (CaMK2) and promoting osteogenic differentiation of MSCs through the calcium signaling pathway. Ultimately, compared with the nongradient hydrogel, this innovative gradient mineralization method exhibited significantly enhanced regeneration capabilities for osteochondral defects, as evidenced by metrics, such as bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N). This holistic strategy provides hope in the field of osteochondral repair. [ABSTRACT FROM AUTHOR]

The complex interactome crucial for successful pregnancy is constituted by the intricate network of endocrine and paracrine signaling pathways, involving gametes, embryos, and the female reproductive tract. Specifically, the oviduct exhibits distinct responses to gametes and early embryos during particular phases of the estrus cycle, a process tightly regulated by reproductive hormones. Moreover, these hormones play a pivotal role in orchestrating cyclical changes within oviductal epithelial cells. To unravel the molecular mechanisms underlying these dynamic changes, our study aimed to investigate the involvement of protein kinase A (PKA) in oviductal epithelial cells throughout the estrus cycle and in advanced pregnancy, extending our studies to oviductal epithelial cell in primary culture. By a combination of 2D-gel electrophoresis, Western blotting, and mass spectrometry, we identified 17 proteins exhibiting differential phosphorylation status mediated by PKA. Among these proteins, we successfully validated the phosphorylation status of heat shock 70 kDa protein (HSP70), aconitase 2 (ACO2), and lamin B1 (LMNB1). Our findings unequivocally demonstrate the dynamic regulation of PKA throughout the estrus cycle in oviductal epithelial cells. Also, analysis by bioinformatics tools suggest its pivotal role in mediating cyclical changes possibly through modulation of apoptotic pathways. This research sheds light on the intricate molecular mechanisms underlying reproductive processes, with implications for understanding fertility and reproductive health. [ABSTRACT FROM AUTHOR]

Estrogens are believed to modulate cognitive functions in part through the modulation of synaptic transmission in the cortex and hippocampus. Administration of 17β‐estradiol (E2) can rapidly enhance excitatory synaptic transmission in the hippocampus and facilitate excitatory synaptic transmission in rat lateral entorhinal cortex via activation of the G protein‐coupled estrogen receptor‐1 (GPER1). To assess the mechanisms through which GPER1 activation facilitates synaptic transmission, we assessed the effects of acute 10 nM E2 administration on pharmacologically isolated evoked excitatory and inhibitory synaptic currents in layer II/III entorhinal neurons. Female Long‐Evans rats were ovariectomized between postnatal day (PD) 63 and 74 and implanted with a subdermal E2 capsule to maintain continuous low levels of E2. Electrophysiological recordings were obtained between 7 and 20 days after ovariectomy. Application of E2 for 20 min did not significantly affect AMPA or NMDA receptor‐mediated excitatory synaptic currents. However, GABA receptor‐mediated inhibitory synaptic currents (IPSCs) were markedly reduced by E2 and returned towards baseline levels during the 20‐min washout period. The inhibition of GABA‐mediated IPSCs was blocked in the presence of the GPER1 receptor antagonist G15. GPER1 can modulate protein kinase A (PKA), but blocking PKA with intracellular KT5720 did not prevent the E2‐induced reduction in IPSCs. GPER1 can also stimulate extracellular signal‐regulated kinase (ERK), a negative modulator of GABAA receptors, and blocking activation of ERK with PD90859 prevented the E2‐induced reduction of IPSCs. E2 can therefore result in a rapid GPER1 and ERK signaling‐mediated reduction in GABA‐mediated IPSCs. This provides a novel mechanism through which E2 can rapidly modulate synaptic excitability in entorhinal layer II/III neurons and may also contribute to E2 and ERK‐dependent alterations in synaptic transmission in other brain areas. [ABSTRACT FROM AUTHOR]

Hippocampal area CA2 has garnered attention in recent times owing to its significant involvement in social memory and distinctive plasticity characteristics. Research has revealed that the CA2 region demonstrates a remarkable resistance to plasticity, particularly in the Schaffer Collateral (SC)‐CA2 pathway. In this study we investigated the role of Nogo‐A, a well‐known axon growth inhibitor and more recently discovered plasticity regulator, in modulating plasticity within the CA2 region. The findings demonstrate that blocking Nogo‐A in male rat hippocampal slices facilitates the establishment of both short‐term and long‐term plasticity in the SC‐CA2 pathway, while having no impact on the Entorhinal Cortical (EC)‐CA2 pathway. Additionally, the study reveals that inhibiting Nogo‐A enables association between the SC and EC pathways. Mechanistically, we confirm that Nogo‐A operates through its well‐known co‐receptor, p75 neurotrophin receptor (p75NTR), and its downstream signaling factor such as Rho‐associated protein kinase (ROCK), as their inhibition also allows plasticity induction in the SC‐CA2 pathway. Additionally, the induction of long‐term depression (LTD) in both the EC and SC‐CA2 pathways led to persistent LTD, which was not affected by Nogo‐A inhibition. Our study demonstrates the involvement of Nogo‐A mediated signaling mechanisms in limiting synaptic plasticity within the CA2 region. [ABSTRACT FROM AUTHOR]

Summary: Boron (B) is crucial for plant growth and development. B deficiency can impair numerous physiological and metabolic processes, particularly in root development and pollen germination, seriously impeding crop growth and yield. However, the molecular mechanism underlying boron signal perception and signal transduction is rather limited.In this study, we discovered that CPK10, a calcium‐dependent protein kinase in the CPK family, has the strongest interaction with the boron transporter BOR1. Mutations in CPK10 led to growth and root development defects under B‐deficiency conditions, while constitutively active CPK10 enhanced plant tolerance to B deficiency.Furthermore, we found that CPK10 interacted with and phosphorylated BOR1 at the Ser689 residue. Through various biochemical analyses and complementation of B transport in yeast and plants, we revealed that Ser689 of BOR1 is important for its transport activity.In summary, these findings highlight the significance of the CPK10‐BOR1 signaling pathway in maintaining B homeostasis in plants and provide targets for the genetic improvement of crop tolerance to B‐deficiency stress. See also the Commentary on this article by Huang, 243: 1633–1635. [ABSTRACT FROM AUTHOR]

In plants, nitric oxide (NO) has become a versatile signaling molecule essential for mediating a wide range of physiological processes under various biotic and abiotic stress conditions. The fundamental function of NO under various stress scenarios has led to a paradigm shift in which NO is now seen as both a free radical liberated from the toxic product of oxidative metabolism and an agent that aids in plant sustenance. Numerous studies on NO biology have shown that NO is an important signal for germination, leaf senescence, photosynthesis, plant growth, pollen growth, and other processes. It is implicated in defense responses against pathogensas well as adaptation of plants in response to environmental cues like salinity, drought, and temperature extremes which demonstrates its multifaceted role. NO can carry out its biological action in a variety of ways, including interaction with protein kinases, modifying gene expression, and releasing secondary messengers. In addition to these signaling events, NO may also be in charge of the chromatin modifications, nitration, and S-nitrosylation-induced posttranslational modifications (PTM) of target proteins. Deciphering the molecular mechanism behind its essential function is essential to unravel the regulatory networks controlling the responses of plants to various environmental stimuli. Taking into consideration the versatile role of NO, an effort has been made to interpret its mode of action based on the post-translational modifications and to cover shreds of evidence for increased growth parameters along with an altered gene expression. • Nitric oxide(NO) plays a significant role in plant biology, affecting crop improvement and sustainable agriculture. • NO has proven to be a multifaceted molecule that signals plant defense under stress conditions. • NO interacts with other signaling molecules to regulate gene expression and enhance the defense system under stress. • Post-translational modifications (PTMs) of NO affect many cellular activities. [ABSTRACT FROM AUTHOR]

P38 mitogen‐activated protein kinases are key in the regulation of the cellular response to stressors. P38 is known to regulate transcription, mRNA processing, stability, and translation. The transcriptional changes mediated by phosphorylated p38 (P‐p38) in response to extracellular stimuli have been thoroughly analyzed in many tissues and organisms. However, the genomic localization of chromatin‐associated P‐p38 remains poorly understood. Here, we analyze the chromatin binding of activated P‐p38 and its role in the response to reactive oxygen species (ROS) in Drosophila S2 cells. We found that P‐p38 is already bound to chromatin in basal conditions. After ROS exposure, chromatin‐associated P‐p38 relocates towards genes involved in the recovery process. Our findings highlight the role of P‐p38 dynamic chromatin binding in orchestrating gene expression responses to oxidative stress. [ABSTRACT FROM AUTHOR]

Protein kinase C isoform ι (PKC ι) is an essential regulator of diverse neurobiological signaling pathways, which has been implicated in general anesthetic action and a variety of nervous neoplasms. Traditional efforts have been primarily addressed on the development of small-molecule inhibitors to target the catalytic or regulatory domain of this kinase. Instead, we herein reported a rational chemical modification of Par3 pseudosubstrate peptide to target the kinase domain with improved affinity and specificity. Structural and energetic analysis suggested that the Par3 peptide can be divided into two binding-independent sections; they are separately anchored to the substrate-binding pocket of PKC ι with two aromatic anchor residues Phe818 and Phe823. The side-chain phenyl group of these two aromatic residues was systematically substituted by different halogen moieties at o -, m - and p -positions of the phenyl group. It is revealed that the p -bromination of Par3 Phe818 and the p -iodinization of Par3 Phe823 residue can separately form two geometrically and energetically satisfactory orthogonal halogen (X)-bond/hydrogen (H)-bond [ortX/H] motifs across Par3 complex interface with PKC ι ; they co-define a so-called ortX/H system and were demonstrated to improve both the binding affinity and recognition specificity of the kinase–peptide interaction by integrating in silico analysis and in vitro assay. The peptide affinity promotes 23.5-fold and 6.6-fold upon the formation of ortX/H motif-I and motif-II, respectively, which further increases to 43.5-fold by forming the complete ortX/H system, indicating cooperativity between the two motifs in the system. In addition, we also demonstrated that the ortX/H system can considerably enhance the peptide selectivity for its cognate PKC ι and noncogante isoforms PKC α and PKC δ. An orthogonal X-bond/H-bond system is rationally designed across the complex interface of PKC ι kinase domain with a Par3 pseudosubstrate peptide by integrating in silico analysis and in vitro assay, which can effectively improve both the peptide affinity to PKC ι and the peptide selectivity for PKC ι over other kinase isoforms. [ABSTRACT FROM AUTHOR]

Mechanistic target of rapamycin kinase (mTOR) is a member of the phosphatidylinositol-3-hydroxide kinase (PI3 K)-related protein kinase family that functions as a central regulator of cell growth, metabolism, proliferation, and survival. The role of the TSC-mTOR signaling pathway in kidney tumors has been implicated in some hamartoma syndromes; however, with the advent and wide utilization of molecular studies, a growing number of kidney tumors have been linked to somatic or germline mutations involving genes that encode for this pathway, including eosinophilic solid and cystic renal cell carcinoma, low-grade oncocytic tumor, eosinophilic vacuolated tumor, renal cell carcinoma with fibromyomatous stroma and angiomyolipoma, among others. Herein, we review the contemporary developments of mTOR pathway-related renal neoplasia, focusing on the clinicopathologic features of the tumor entities. [ABSTRACT FROM AUTHOR]

Pepper is a vegetable that is used and cultivated worldwide. The quality and production of pepper are reduced by fruit anthracnose disease caused by Colletotrichum scovillei. The highly conserved fungal sucrose non‐fermenting 1 (SNF1)‐related AMPK protein kinases are implicated in the pathogenicity and differentiation of several destructive foliar fungal pathogens; in addition, they affect fungal growth in the presence of glucose at different concentrations and under different environmental stresses. However, the function of SNF1 in C. scovillei is unclear. We functionally characterized SNF1 of C. scovillei using a targeted deletion mutant (ΔCssnf1) generated by homology‐dependent replacement. ΔCssnf1 was severely impaired in mycelial growth under glucose‐limited conditions; multiple defects in conidiation, conidial germination, appressorium formation, lipid degradation and vacuole formation were also observed. Compared to the wild type, ΔCssnf1 caused anthracnose disease of reduced severity on intact and wounded pepper fruits. These defects were recovered in the complemented strain (Cssnf1c). Taken together, our findings implicate CsSNF1 in the growth, development and virulence of C. scovillei. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a common pathological process in the progression of several chronic liver diseases to cirrhosis and hepatocellular carcinoma. Therefore, the development of medications that can repress the progress of liver fibrosis is essential. We discovered that initially, 12β-(m-methyl-benzoyl)-11,12-dihydro oleanolic acid (12d-OA), a farnesoid X receptor (FXR) modulator, possessed potential anti-fibrotic properties. Through an in-depth study, we revealed that 12d-OA not only inhibited the expression of fibrogenic markers in the LX-2 cells and HSC-T6 cells but also exhibited significant protective effects against liver injury and liver fibrosis in bile duct ligation (BDL) rats. Further exploration of its molecular mechanism indicated that 12d-OA exerted antifibrotic activity by inhibiting the extracellular signal-regulated kinase (ERK)/stress-activated protein kinase (p38) signaling pathways. Consequently, the great effects of 12d-OA in vitro and in vivo suggest that it may be a good candidate for liver fibrosis. [ABSTRACT FROM AUTHOR]

Aeromonas veronii is an important pathogen found in various aquatic environments and products, posing a threat to public health. The Hanks‐like serine/threonine protein kinase is closely linked to the pathogenesis of pathogenic bacteria, but the exact role of YihE in A. veronii remains still unknown. To study the specific function of the YihE kinase, we constructed a knockout mutant of the yihE gene in A. veronii. The deletion of the yihE gene resulted in changes to the metabolism of L‐arginine‐AMC and acetic acid, as well as enhanced resistance to ampicillin and kanamycin in A. veronii. Additionally, the ΔyihE strain demonstrated a 1.4‐fold increase in biofilm formation ability and a 1.8‐fold decrease in adhesion and invasion to EPCs when compared to the wild‐type strain. A significant decrease in cytotoxicity was observed at 2 and 3 h post‐infection with EPCs compared to the wild‐type strain. Additionally, the deletion of the yihE gene was associated with a significant decrease in motility of the strain. Furthermore, the deletion of the yihE gene resulted in a 1.44‐fold increase in the LD50 of A. veronii in zebrafish. These findings offer valuable insights into the pathogenic mechanisms of A. veronii. [ABSTRACT FROM AUTHOR]

Members of the Protein kinases D (PKD) family are described as regulators of T cell responses. From the two T cell‐expressed isoforms PKD2 and PKD3, so far mainly the former was thoroughly investigated and is well understood. Recently, we have investigated also PKD3 using conventional as well as conditional T cell‐specific knockout models. These studies suggested PKD3 to be a T cell‐extrinsic regulator of the cells' fate. However, these former model systems did not take into account possible redundancies with the highly homologous PKD2. To overcome this issue and thus properly unravel PKD3's T cell‐intrinsic functions, here we additionally used a mouse model overexpressing a constitutively active isoform of PKD3 specifically in the T cell compartment. These transgenic mice showed a slightly higher proportion of central memory T cells in secondary lymphoid organs and blood. This effect could not be explained via differences upon polyclonal stimulation in vitro, however, may be connected to the observed developmental aberrances in the CD8 single positive compartment during thymic development. Lastly, the observed alterations in the CD8+ T cell compartment did not impact proper immune response upon immunization with ovalbumin or in a subcutaneous tumour model suggesting only a small to absent biological relevance. Taking together the knowledge of all our published studies on PKD3 in the T cell compartment, we now conclude that T cell‐intrinsic PKD3 is a fine‐tuner of central memory T cell as well as CD8 single positive thymocyte development. [ABSTRACT FROM AUTHOR]

Developing novel therapies that outperform the existing chemotherapeutic treatments is required for treatment-resistant ovarian clear cell carcinoma. We investigated the antitumor effect of metformin on ovarian clear cell carcinoma, enhancement of the antitumor effect by its combination with chemotherapy, and its molecular regulatory mechanism. First, we evaluated the viability of ovarian clear cell carcinoma lines using the water-soluble tetrazolium-1 assay and found that metformin suppressed cell viability. Cell viability was significantly suppressed by co-treatment with cisplatin and metformin. In contrast, co-treatment with paclitaxel and metformin showed no significant difference in viability compared with the group without metformin. Western blot analysis showed increased phosphorylation of AMP-activated protein kinase in some cell lines and suppressed phosphorylation of the mammalian target of rapamycin in a particular cell line. Flow cytometry analysis revealed a significant increase in the rate of apoptosis in the metformin-treated group and rate of cell cycle arrest at the G2/M phase in a particular cell line. These results indicated that metformin may be effective against cultured ovarian clear cell carcinoma cells, particularly in combination with cisplatin. [ABSTRACT FROM AUTHOR]

Introduction: Limited awareness exists regarding real-world data (RWD) for palbociclib in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced/metastatic breast cancer in populations from certain countries outside of Western regions. Methods: A systematic scoping review was conducted using PubMed and Embase to evaluate RWD for palbociclib from countries outside of Western regions that are underrepresented in clinical trials. Search criteria were aligned with our research question for relevant English-language publications, without restrictions on publication date, followed by Phase 1 (title and abstract) and Phase 2 (full-text) screening of retrieved citations as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data analyses of eligible studies were done separately for abstracts and full-text publications to enhance the precision and reliability of the results. Results: Database search yielded 1485 non-duplicate records, 46 qualified for inclusion, of which 47.8% were published as full text. The analysis of outcomes, based exclusively on full-text publications that collectively included 2048 patients treated with palbociclib, revealed the median progression-free survival (PFS) of 20.2–36.7 months, overall survival (OS) of 39.9 months (reported in one publication) and objective response rate (ORR) of 45.3–80.0% with first-line treatment. In ≥ second line, the median PFS, OS and ORR ranged from 7.0 to 24.2 months, 11 to 19.6 months, and 13.9% to 47.9%, respectively. The safety profile of palbociclib was similar to that reported in pivotal clinical studies, and no new safety concerns were identified. Conclusions: A comprehensive volume of evidence demonstrates that palbociclib's effectiveness and safety profile in real-world settings align with those observed in clinical trials, offering valuable insights for clinical decision-making in countries outside of Western regions underrepresented in clinical trials. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is the most common malignant cancer of the head and neck, with high morbidity and mortality, ranking as the sixth most common cancer in the world. The treatment of OSCC is mainly radiotherapy, chemotherapy and surgery, however, the prognosis of patients is still poor and the recurrence rate is high. This paper reviews the range of effects of natural medicinal plant active ingredients (NMPAIs) on OSCC cancer, including the types of NMPAIs, anti-cancer mechanisms, involved signaling pathways, and clinical trials. The NMPAIs include terpenoids, phenols, flavonoids, glycosides, alkaloids, coumarins, and volatile oils. These active ingredients inhibit proliferation, induce apoptosis and autophagy, inhibit migration and invasion of OSCC cells, and regulate cancer immunity to exert anti-cancer effects. The mechanism involves signaling pathways such as mitogen-activated protein kinase, phosphatidylinositol 3 kinase/protein kinase B, nuclear factor kappa B, miR-22/WNT1/β-catenin and Nrf2/Keap1. Clinically, NMPAIs can inhibit the growth of OSCC, and the combined drug is more effective. Natural medicinal plants are promising candidates for the treatment of OSCC. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether Buthus martensii karsch (Scorpiones), Scolopendra subspinipes mutilans L. Koch (Scolopendra) and Gekko gecko Linnaeus (Gekko) could ameliorate the hypoxic tumor microenvironment and inhibit lung cancer growth and metastasis by regulating phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin/hypoxia-inducible factor-1α (PI3K/AKT/mTOR/HIF-1α) signaling pathway. Methods: Male C57BL/6J mice were inoculated with luciferase labeled LL/2-luc-M38 cell suspension to develop lung cancer models, with rapamycin and cyclophosphamide as positive controls. Carboxy methyl cellulose solutions of Scorpiones, Scolopendra and Gekko were administered intragastrically as 0.33, 0.33, and 0.83 g/kg, respectively once daily for 21 days. Fluorescent expression were detected every 7 days after inoculation, and tumor growth curves were plotted. Immunohistochemistry was performed to determine CD31 and HIF-1α expressions in tumor tissue and microvessel density (MVD) was analyzed. Western blot was performed to detect the expression of PI3K/AKT/mTOR/HIF-1α signaling pathway-related proteins. Enzyme-linked immunosorbent assay was performed to detect serum basic fibroblast growth factor (bFGF), transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) in mice. Results: Scorpiones, Scolopendra and Gekko prolonged the survival time and inhibited lung cancer metastasis and expression of HIF-1α (all P<0.01). Moreover, Scorpiones, Scolopendra and Gekko inhibited the phosphorylation of AKT and ribosomal protein S6 kinase (p70S6K) (P<0.05 or P<0.01). In addition, they also decreased the expression of CD31, MVD, bFGF, TGF-β1 and VEGF compared with the model group (P<0.05 or P<0.01). Conclusion: Scorpiones, Scolopendra and Gekko all showed beneficial effects on lung cancer by ameliorating the hypoxic tumor microenvironment via PI3K/AKT/mTOR/HIF-1α signaling pathway. [ABSTRACT FROM AUTHOR]

AQP3 (aquaporin 3 (Gill blood group)), a member of the AQP family, is an aquaglyceroporin which transports water, glycerol and small solutes across the plasma membrane. Beyond its role in fluid transport, AQP3 plays a significant role in regulating various aspects of tumor cell behavior, including cell proliferation, migration, and invasion. Nevertheless, the underlying regulatory mechanism of AQP3 in tumors remains unclear. Here, for the first time, we report that AQP3 is a direct target for ubiquitination by the SCFFBXW5 complex. In addition, we revealed that downregulation of FBXW5 significantly induced AQP3 expression to prompt macroautophagic/autophagic cell death in hepatocellular carcinoma (HCC) cells. Mechanistically, AQP3 accumulation induced by FBXW5 knockdown led to the degradation of PDPK1/PDK1 in a lysosomal-dependent manner, thus inactivating the AKT-MTOR pathway and inducing autophagic death in HCC. Taken together, our findings revealed a previously undiscovered regulatory mechanism through which FBXW5 degraded AQP3 to suppress autophagic cell death via the PDPK1-AKT-MTOR axis in HCC cells. Abbreviation: BafA1: bafilomycin A1; CQ: chloroquine; CRL: CUL-Ring E3 ubiquitin ligases; FBXW5: F-box and WD repeat domain containing 5; HCC: hepatocellular carcinoma; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; 3-MA: 3-methyladenine; PDPK1/PDK1: 3-phosphoinositide dependent protein kinase 1; RBX1/ROC1: ring-box 1; SKP1: S-phase kinase associated protein 1; SCF: SKP1-CUL1-F-box protein. [ABSTRACT FROM AUTHOR]

Hypertension is a globally prevalent disease, but the pathogenesis remains largely unclear. AMP-activated protein kinase (AMPK) is a nutrition-sensitive signal of cellular energy metabolism, which has a certain influence on the development of hypertension. Previously, we found a down-regulation of the phosphorylated (p-) form of AMPK, and the up-regulation of the angiotensin II type 1 receptor (AT1-R) and that of p-ERK1/2 in the hypothalamic paraventricular nucleus (PVN) of hypertensive rats. However, the exact mechanism underlying the relationship between AMPK and AT1-R in the PVN during hypertension remains unclear. Thus, we hypothesized that AMPK modulates AT1-R through the ERK1/2-NF-κB pathway in the PVN, thereby inhibiting sympathetic nerve activity and improving hypertension. To examine this hypothesis, we employed a renovascular hypertensive animal model developed via two-kidney, one-clip (2K1C) and sham-operated (SHAM). Artificial cerebrospinal fluid (aCSF), used as vehicle, or 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide (AICAR, an AMPK activator, 60 μg/day) was microinjected bilaterally in the PVN of these rats for 4 weeks. In 2K1C rats, there an increase in systolic blood pressure (SBP) and circulating norepinephrine (NE). Also, the hypertensive rats had lowered expression of p-AMPK and p-AMPK/AMPK, elevated expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R, increased NF-κB p65 activity in the PVN compared with the levels of these biomarkers in SHAM rats. Four weeks of bilateral PVN injection of AMPK activator AICAR, attenuated the NE level and SBP, increased the expression of p-AMPK and p-AMPK/AMPK, lessened the NF-κB p65 activity, decreased the expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R in the PVN of 2K1C rats. Data from this study imply that the activation of AMPK within the PVN suppressed AT1-R expression through inhibiting the ERK1/2-NF-κB pathway, decreased the activity of the sympathetic nervous system, improved hypertension. [ABSTRACT FROM AUTHOR]

Cold stress, a prominent adverse environmental factor, severely hinders rice growth and productivity. Unraveling the complex mechanisms governing chilling tolerance in rice is crucial for molecular breeding of cold-tolerant varieties. Here, we identify an APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factor, OsERF52, as a positive modulator in response to low temperatures. OsERF52 directly regulates the expression of C-Repeat Binding Factor (CBF) genes in rice. In addition, Osmotic Stress/ABA-Activated Protein Kinase 9-mediated phosphorylation of OsERF52 at S261 enhances its stability and interaction with Ideal Plant Architecture 1 and OsbHLH002/OsICE1. This collaborative activation leads to the expression of OsCBFs, thereby initiating the chilling response in rice. Notably, plants with base-edited OsERF52S261D-3HA exhibit enhanced chilling resistance without yield penalty. Our findings unveil the mechanism orchestrated by a regulatory framework involving a protein kinase and transcription factors from diverse families, offering potential genetic resources for developing chilling-tolerant rice varieties. [ABSTRACT FROM AUTHOR]

AMP‐activated protein kinase (AMPK), a crucial regulatory kinase, monitors energy levels, conserving ATP and boosting synthesis in low‐nutrition, low‐energy states. Its sensitivity links microenvironmental changes to cellular responses. As the primary support structure and endocrine organ, the maintenance, and repair of bones are closely associated with the microenvironment. While a series of studies have explored the effects of specific microenvironments on bone, there is lack of angles to comprehensively evaluate the interactions between microenvironment and bone cells, especially for bone marrow mesenchymal stem cells (BMMSCs) which mediate the differentiation of osteogenic lineage. It is noteworthy that accumulating evidence has indicated that AMPK may serve as a hub between BMMSCs and microenvironment factors, thus providing a new perspective for us to understand the biology and pathophysiology of stem cells and bone. In this review, we emphasize AMPK's pivotal role in bone microenvironment modulation via ATP, inflammation, reactive oxygen species (ROS), calcium, and glucose, particularly in BMMSCs. We further explore the use of AMPK‐activating drugs in the context of osteoarthritis and osteoporosis. Moreover, building upon the foundation of AMPK, we elucidate a viewpoint that facilitates a comprehensive understanding of the dynamic relationship between the microenvironment and bone homeostasis, offering valuable insights for prospective investigations into stem cell biology and the treatment of bone diseases. [ABSTRACT FROM AUTHOR]

Melatonin, the hormone of the pineal gland, possesses a range of physiological functions, and recently, its anticancer effect has become more apparent. A more thorough understanding of molecular alterations in the components of several signaling pathways as new targets for cancer therapy is needed because of current innate restrictions such as drug toxicity, side effects, and acquired or de novo resistance. The PI3K/Akt/mTOR pathway is overactivated in many solid tumors, such as breast and ovarian cancers. This pathway in normal cells is essential for growth, proliferation, and survival. However, it is an undesirable characteristic in malignant cells. We have reviewed multiple studies about the effect of melatonin on breast and ovarian cancer, focusing on the PI3K/Akt/mTOR pathway. Melatonin exerts its inhibitory effects via several mechanisms. A: Downregulation of downstream or upstream components of the signaling pathway such as phosphatase and tensin homolog (PTEN), phosphatidylinositol (3,4,5)‐trisphosphate kinase (PI3K), p‐PI3K, Akt, p‐Akt, mammalian target of rapamycin (mTOR), and mTOR complex1 (mTORC1). B: Apoptosis induction by decreasing MDM2 expression, a downstream target of Akt, and mTOR, which leads to Bad activation in addition to Bcl‐XL and p53 inhibition. C: Induction of autophagy in cancer cells via activating ULK1 after mTOR inhibition, resulting in Beclin‐1 phosphorylation. Beclin‐1 with AMBRA1 and VPS34 promotes PI3K complex I activity and autophagy in cancer cells. The PI3K/Akt/mTOR pathway overlaps with other intracellular signaling pathways and components such as AMP‐activated protein kinase (AMPK), Wnt/β‐catenin, mitogen‐activated protein kinase (MAPK), and other similar pathways. Cancer therapy can benefit from understanding how these pathways interact and how melatonin affects these pathways. [ABSTRACT FROM AUTHOR]

Background: Type 2 diabetes mellitus, one of the most prevalent metabolic disorders worldwide, is closely linked with an enhanced risk of atherosclerosis. However, the molecular mechanism of this linkage is not still clear. Genetic variations in the mTOR gene may increase the susceptibility of individuals to these diseases. Methods: One hundred nine diabetic patients and 375 healthy subjects participated in this study. mTOR Single Nucleotide Polymorphism (SNP) rs2295080 was determined using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Results: Comparison of genotypic, allelic, and genotypic combination frequencies between cases and controls revealed no significant result. Nevertheless, the frequency of rs2295080 GT + TT genotype was significantly more in diabetic women with atherosclerosis compared with those without atherosclerosis (p = 0.047). Besides, the rs2295080 G allele was more frequently detected in diabetic women without atherosclerosis compared to those with atherosclerosis (p = 0.046). Conclusion: The rs2295080 GT + TT genotype predisposes Iranian diabetic women to atherosclerosis, while the rs2295080 G allele protects them against atherosclerosis. However, additional experiments using larger sample sizes are needed to verify this result. [ABSTRACT FROM AUTHOR]

Drought stress is a common abiotic challenge that profoundly impacts plant growth and development. As sessile organisms, plants rely on various physiological and morphological adaptations to cope with drought conditions. The CIPK (calcineurin B‐like protein‐interacting protein kinase) family proteins play a pivotal role in mediating plant responses to abiotic stress through modulation of cellular membrane events via the CBL‐CIPK complex. However, reports documenting the CIPKs’ regulation of non‐membrane events are scant. In this study, we discovered a novel subcellular localisation pattern of the AtCIPK20 protein of Arabidopsis, specifically to cortical microtubules (cMT), which is distinct from previously reported localisation patterns of plant CIPKs. AtCIPK20 regulates ABA‐induced loss of cMT organisation in guard cells, thereby facilitating stomatal closure, mitigating leaf water loss, and protecting plants from drought stress in Arabidopsis. The C‐terminal regulatory domain of AtCIPK20 governs its cMT targeting, whereas the interaction of AtCIPK20 with its CBL partners disrupts this localisation. Notably, the cMT targeting characteristic of AtCIPK20 is not exclusive, as several other CIPK members in Arabidopsis, maize, and rice exhibit similar localisation patterns. These findings broaden our current understanding of the role of plant CIPK members in abiotic stress resistance and suggest that future exploration of CIPK molecular functions should adopt a more comprehensive perspective. [ABSTRACT FROM AUTHOR]

TOR (target of rapamycin), a ubiquitous protein kinase central to cellular homeostasis maintenance, fundamentally regulates ribosome biogenesis in part by its target La-related protein 1 (LARP1). Among other target transcripts, LARP1 specifically binds TOP (terminal oligopyrimidine) mRNAs encoding all 80 ribosomal proteins in a TOR-dependent manner through its C-terminal region containing the DM15 module. Though the functional implications of the LARP1 interaction with target mRNAs is controversial, it is clear that the TOP-LARP1-TOR axis is critical to cellular health in humans. Its existence and role in evolutionarily divergent animals remain less understood. We focused our work on expanding our knowledge of the first arm of the axis: the connection between LARP1-DM15 and the 5' TOP motif. We show that the overall DM15 architecture observed in humans is conserved in fruit fly and zebrafish. Both adopt familiar curved arrangements of HEAT-like repeats that bind 5' TOP mRNAs on the same conserved surface, although molecular dynamics simulations suggest that the N-terminal fold of the fruit fly DM15 is predicted to be unstable and unfold. We demonstrate that each ortholog interacts with TOP sequences with varying affinities. Importantly, we determine that the ability of the DM15 region to bind some TOP sequences but not others might amount to the context of the RNA structure, rather than the ability of the module to recognize some sequences but not others. We propose that TOP mRNAs may retain similar secondary structures to regulate LARP1 DM15 recognition. [ABSTRACT FROM AUTHOR]

Respiratory diseases are a growing concern in public health because of their potential to endanger the global community. Cell death contributes critically to the pathophysiology of respiratory diseases. Recent evidence indicates that necroptosis, a unique form of programmed cell death (PCD), plays a vital role in the molecular mechanisms underlying respiratory diseases, distinguishing it from apoptosis and conventional necrosis. Necroptosis is a type of inflammatory cell death governed by receptor-interacting serine/threonine protein kinase 1 (RIPK1), RIPK3, and mixed-lineage kinase domain-like protein (MLKL), resulting in the release of intracellular contents and inflammatory factors capable of initiating an inflammatory response in adjacent tissues. These necroinflammatory conditions can result in significant organ dysfunction and long-lasting tissue damage within the lungs. Despite evidence linking necroptosis to various respiratory diseases, there are currently no specific alternative treatments that target this mechanism. This review provides a comprehensive overview of the most recent advancements in understanding the significance and mechanisms of necroptosis. Specifically, this review emphasizes the intricate association between necroptosis and respiratory diseases, highlighting the potential use of necroptosis as an innovative therapeutic approach for treating these conditions. [ABSTRACT FROM AUTHOR]

Targeting receptor‐interacting protein kinase 1 (RIPK1) has emerged as a promising therapeutic stratagem for neurodegenerative disorders, particularly Alzheimer's disease (AD). A positron emission tomography (PET) probe enabling brain RIPK1 imaging can provide a powerful tool to unveil the neuropathology associated with RIPK1. Herein, the development of a new PET radioligand, [11C]CNY‐10 is reported, which may enable brain RIPK1 imaging. [11C]CNY‐10 is radiosynthesized with a high radiochemical yield (41.8%) and molar activity (305 GBq/µmol). [11C]CNY‐10 is characterized by PET imaging in rodents and a non‐human primate, demonstrating good brain penetration, binding specificity, and a suitable clearance kinetic profile. It is performed autoradiography of [11C]CNY‐10 in human AD and healthy control postmortem brain tissues, which shows strong radiosignal in AD brains higher than healthy controls. Subsequently, it is conducted further characterization of RIPK1 in AD using [11C]CNY‐10‐based PET studies in combination with immunohistochemistry leveraging the 5xFAD mouse model. It is found that AD mice revealed RIPK1 brain signal significantly higher than WT control mice and that RIPK1 is closely related to amyloid plaques in the brain. The studies enable further translational studies of [11C]CNY‐10 for AD and potentially other RIPK1‐related human studies. [ABSTRACT FROM AUTHOR]

In this work, we design a new approach for digital counting-based protein kinase activity assay by using plasmonic nanoparticle-assisted single-molecule dynamic binding. This method breaks the concentration-dependent limitation in single-molecule detection and displays good selectivity and sensitivity with a detection limit as low as 0.0001 U mL-1 for the protein kinase A (PKA) assay, which would find broad applications in drug screening and medical investigations. [ABSTRACT FROM AUTHOR]

Background: An elevated endogenous cortisol level due to the peripartum stress is one of the risk factors of postpartum bovine uterine infections. Selenium is a trace element that elicits anti-inflammation and antioxidation properties. This study aimed to reveal the modulatory effect of selenium on the inflammatory response of primary bovine endometrial stromal cells in the presence of high-level cortisol. The cells were subjected to lipopolysaccharide to establish cellular inflammation. The mRNA expression of toll-like receptor 4 (TLR4), proinflammatory factors, and selenoproteins was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blot and immunofluorescence. Results: The pretreatment with sodium selenite (2 and 4 µΜ) resulted in a down-regulation of TLR4 and genes encoding proinflammatory factors, including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor α, cyclooxygenase 2, and inducible nitric oxide synthase. Selenium inhibited the activation of NF-κB and the phosphorylation of mitogen-activated protein kinase kinase, extracellular signal-regulated kinase, p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase. The suppression of those genes and pathways by selenium was more significant in the presence of high cortisol level (30 ng/mL). Meanwhile the gene expression of glutathione peroxidase 1 and 4 was promoted by selenium, and was even higher in the presence of cortisol and selenium. Conclusions: The anti-inflammatory action of selenium is probably mediated through NF-κB and MAPK, and is augmented by cortisol in primary bovine endometrial stromal cells. [ABSTRACT FROM AUTHOR]

Summary In Arabidopsis, the enzymatically active lysin motif‐containing receptor‐like kinase (LysM‐RLK) CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) and the pseudokinases LYSIN MOTIF‐CONTAINING RECEPTOR‐LIKE KINASE 5 (LYK5) and LYK4 are the core components of the canonical chitin receptor complex. CERK1 dimerizes and autophosphorylates upon chitin binding, resulting in activation of chitin signaling. In this study, we clarified and further elucidated the individual contributions of LYK4 and LYK5 to chitin‐dependent signaling using mutant (combination)s and stably transformed Arabidopsis plants expressing fluorescence‐tagged LYK5 and LYK4 variants from their endogenous promoters. Our analyses revealed that LYK5 interacts with CERK1 upon chitin treatment, independently of LYK4 and vice versa. We show that chitin‐induced autophosphorylation of CERK1 is predominantly dependent on LYK5, whereas chitin‐triggered ROS generation is almost exclusively mediated by LYK4. This suggests specific signaling functions of these two co‐receptor proteins apart from their redundant function in mitogen‐activated protein kinase (MAPK) signaling and transcriptional reprogramming. Moreover, we demonstrate that LYK5 is subject to chitin‐induced and CERK1‐dependent ubiquitination, which serves as a signal for chitin‐induced internalization of LYK5. Our experiments provide evidence that a combination of phosphorylation and ubiquitination events controls LYK5 removal from the plasma membrane via endocytosis, which likely contributes to receptor complex desensitization. [ABSTRACT FROM AUTHOR]

Background: The mitogen-activated protein kinase (MAPK) cascade is crucial cell signal transduction mechanism that plays an important role in plant growth and development, metabolism, and stress responses. The MAPK cascade includes three protein kinases, MAPK, MAPKK, and MAPKKK. The three protein kinases mediate signaling to downstream response molecules by sequential phosphorylation. The MAPK gene family has been identified and analyzed in many plants, however it has not been investigated in alfalfa. Results: In this study, Medicago sativa MAPK genes (referred to as MsMAPKs) were identified in the tetraploid alfalfa genome. Eighty MsMAPKs were divided into four groups, with eight in group A, 21 in group B, 21 in group C and 30 in group D. Analysis of the basic structures of the MsMAPKs revealed presence of a conserved TXY motif. Groups A, B and C contained a TEY motif, while group D contained a TDY motif. RNA-seq analysis revealed tissue-specificity of two MsMAPKs and tissue-wide expression of 35 MsMAPKs. Further analysis identified MsMAPK members responsive to drought, salt, and cold stress conditions. Two MsMAPKs (MsMAPK70 and MsMAPK75) responds to salt and cold stresses; two MsMAPKs (MsMAPK60 and MsMAPK73) responds to cold and drought stresses; four MsMAPKs (MsMAPK1, MsMAPK33, MsMAPK64 and MsMAPK71) responds to salt and drought stresses; and two MsMAPKs (MsMAPK5 and MsMAPK7) responded to all three stresses. Conclusion: This study comprehensively identified and analysed the alfalfa MAPK gene family. Candidate genes related to abiotic stresses were screened by analysing the RNA-seq data. The results provide key information for further analysis of alfalfa MAPK gene functions and improvement of stress tolerance. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is the primary malignant tumor of the liver. c-Myc is one of the most common oncogenes in clinical settings, and amplified levels of c-Myc are frequently found in HCC. Histone deacetylase inhibitors (HDACi), such as Trichostatin A (TSA), hold enormous promise for the treatment of HCC. However, the potential and mechanism of TSA in the treatment of c-Myc-induced HCC are unclear. In this study, we investigated the effects of TSA treatment on a c-Myc-induced HCC model in mice. TSA treatment delayed the development of HCC, and liver function indicators such as ALT, AST, liver weight ratio, and spleen weight ratio demonstrated the effectiveness of TSA treatment. Oil red staining further demonstrated that TSA attenuated lipid accumulation in the HCC tissues of mice. Through mRNA sequencing, we identified that TSA mainly affected cell cycle and fatty acid degradation genes, with alcohol dehydrogenase 4 (ADH4) potentially being the core molecular downstream target. QPCR, immunohistochemistry, and western blot analysis revealed that ADH4 expression was repressed by c-Myc and restored after TSA treatment both in vitro and in vivo. Furthermore, we observed that the levels of total NAD+ and NADH, NAD+, NAD+/NADH, and ATP concentration increased after c-Myc transfection in liver cells but decreased after TSA intervention. The levels of phosphorylated protein kinase B (p-AKT) and p-mTOR were identified as targets regulated by TSA, and they governed the ADH4 expression and the downstream regulation of total NAD+ and NADH, NAD+, NAD+/NADH, and ATP concentration. Overall, our study suggests that TSA has a therapeutic effect on c-Myc-induced HCC through the AKT-mTOR-ADH4 pathway. These findings provide valuable insights into the potential treatment of HCC using TSA and shed light on the underlying molecular mechanisms involved. [ABSTRACT FROM AUTHOR]

Aim Methods Results Conclusions AMP‐activated protein kinase (AMPK) is activated during cellular energy perturbation. AMPK complexes are composed of three subunits and several variants of AMPK are expressed in skeletal muscle. The regulatory AMPKγ3 subunit is predominantly expressed in fast‐twitch muscle fibers. A human AMPKγ3 R225W mutation has been described. The mutation increases the total pool of AMPK activity in cells cultured from R225W carrier muscle and is associated with increased glycogen levels in mature skeletal muscle. This led to the idea of AMPKγ3 being involved in the regulation of skeletal muscle glycogen levels. Evidence for this causative link remains to be provided.We studied muscle biopsies from human carriers of the AMPKγ3 R225W mutation and we developed a novel AMPKγ3 R225W knock‐in mouse model (KI HOM). Through in vitro, in situ, and ex vivo techniques, we investigated AMPK activity, AMPK function, and glycogen levels in skeletal muscle of humans and mice.In human carriers, the basal AMPKγ3‐associated activity was reduced when assayed in the absence of exogenous AMP. No difference was observed when assayed under AMP saturation, which was supported by findings in muscle of KI HOM mice. Furthermore, effects of AICAR/muscle contraction on AMPKγ3‐associated activity were absent in KI HOM muscle. Muscle glycogen levels were not affected by the mutation in human carriers or in KI HOM mice.The AMPKγ3 R225W mutation does not impact the AMPK‐associated activity in human skeletal muscle and the mutation is not linked to glycogen accumulation. The R225W mutation ablates the AMPKγ3‐associated activation by AICAR/muscle contractions, presumably due to loss of nucleotide binding in the CBS 1 domain of AMPKγ3. [ABSTRACT FROM AUTHOR]

TORC1 (target of rapamycin complex 1) is a highly conserved protein kinase that plays a central role in regulating cell growth. Given the role of mammalian TORC1 (mTORC1) in metabolism and disease, understanding mTORC1 downstream signaling and feedback loops is important. mTORC1 recognizes some of its substrates via a five amino acid binding sequence called the TOR signaling (TOS) motif. mTORC1 binding to a TOS motif facilitates phosphorylation of a distinct, distal site. Here, we show that LST2, also known as ZFYVE28, contains a TOS motif (amino acids 401 to 405) and is directly phosphorylated by mTORC1 at serine 670 (S670). mTORC1-mediated S670 phosphorylation promotes LST2 monoubiquitination on lysine 87 (K87). Monoubiquitinated LST2 is stable and displays a broad reticular distribution. When mTORC1 is inactive, unphosphorylated LST2 is degraded by the proteasome. The absence of LST2 enhances EGFR (epidermal growth factor receptor) signaling. We propose that mTORC1 negatively feeds back on its upstream receptor EGFR via LST2. [ABSTRACT FROM AUTHOR]

The mitogen‐activated protein kinase (MAPK) cascade (MAPKKK‐MAPKK‐MAPK) plays a critical role in biotic and abiotic stress responses and abscisic acid (ABA) signalling. A previous study has shown that the ABA‐activated MKK1‐MPK1 cascade is essential in regulating ABA response and stress tolerance in rice. However, the specific MAPKKK upstream of the MKK1‐MPK1 cascade in ABA signalling remains unknown. Here, we identified that MAPKKK28, a previously uncharacterized member of the rice MEKK family, is involved in regulating ABA responses, including seed germination, root growth, stomatal closure, and the tolerance to oxidative stress and osmotic stress. We found that MAPKKK28 directly interacts with and phosphorylates MKK1. Further analysis indicated that the activation of both MKK1 and MPK1 depends on MAPKKK28 in ABA signalling. Genetic analysis revealed that MAPKKK28 functions upstream of the MKK1‐MPK1 cascade to positively regulate ABA responses and enhance tolerance to oxidative and osmotic stress. These results not only reveal a new complete MAPK cascade in plants but also uncover its importance in ABA signalling. [ABSTRACT FROM AUTHOR]

Neutrophils are the first immune cells to reach inflamed sites and contribute to the pathogenesis of chronic inflammatory skin diseases. Yet, little is known about the pattern of neutrophil infiltration in inflamed skin in vivo and the mechanisms mediating their recruitment. Here, we provide insight into the dynamics of neutrophil infiltration in skin in response to acute or repeated inflammatory stress, highlighting a novel keratinocyte- and keratin 17 (K17)-dependent mechanism that regulates neutrophil recruitment to inflamed skin. We used the phorbol ester TPA and UVB, alone or in combination, to induce sterile inflammation in mouse skin. A single TPA treatment results in a neutrophil influx in the dermis that peaks at 12 h and resolves within 24 h. A subsequent TPA treatment or a UVB challenge, when applied 24 h but not 48 h later, accelerates, amplifies, and prolongs neutrophil infiltration. This transient amplification response (TAR) is mediated by local signals in inflamed skin, can be recapitulated in ex vivo culture, and involves the K17-dependent sustainment of protein kinase Cα (PKCα) activity and release of chemoattractants by stressed keratinocytes. K17 binds RACK1, a scaffold protein essential for PKCα activity. The N-terminal head domain of K17 is crucial for its association with RACK1 and regulation of PKCα activity. Analysis of RNAseq data reveals a signature consistent with TAR and PKCα activation in inflammatory skin diseases. These findings uncover a novel, keratin-dependent mechanism that amplifies neutrophil recruitment in skin under stress, with direct implications for inflammatory skin disorders. Neutrophils contribute to the pathogenesis of chronic inflammatory diseases, but the mechanisms underlying their recruitment to inflamed skin are unclear. This study shows that repeated acute stress to the skin amplifies a neutrophil infiltration response involving keratin 17 and PKCα. [ABSTRACT FROM AUTHOR]

Summary DNA sensors generally initiate innate immune responses through the production of type I interferons. While extensively studied for host defense against invading pathogens, emerging evidence highlights the involvement of DNA sensors in metabolic and cardiovascular diseases. Elevated levels of modified, damaged, or ectopically localized self‐DNA and non‐self‐DNA have been observed in patients and animal models with obesity, diabetes, fatty liver disease, and cardiovascular disease. The accumulation of cytosolic DNA aberrantly activates DNA signaling pathways, driving the pathological progression of these disorders. This review highlights the roles of specific DNA sensors, such as cyclic AMP‐GMP synthase and stimulator of interferon genes (cGAS‐STING), absent in melanoma 2 (AIM2), toll‐like receptor 9 (TLR9), interferon gamma‐inducible protein 16 (IFI16), DNA‐dependent protein kinase (DNA‐PK), and DEAD‐box helicase 41 (DDX41) in various metabolic disorders. We explore how DNA signaling pathways in both immune and non‐immune cells contribute to the development of these diseases. Furthermore, we discuss the intricate interplay between metabolic stress and immune responses, offering insights into potential therapeutic targets for managing metabolic and cardiovascular disorders. Understanding the mechanisms of DNA sensor signaling in these contexts provides a foundation for developing novel interventions aimed at mitigating the impact of these pervasive health issues. [ABSTRACT FROM AUTHOR]

Background: Intracellular sensing of lipopolysaccharide (LPS) is essential for the immune response against gram-negative bacteria and results in activation of caspase-11 and pyroptotic cell death with fatal consequences in sepsis. We found the neuronal guidance receptor plexin C1 (PLXNC1) influences the intracellular response to LPS. Methods: We employed a murine model of sepsis via cecal ligation and binding (CLP), using PLXNC1-/- mice and littermate controls, and additionally transfected murine bone-marrow-derived macrophages (BMDMs) from both genotypes with LPS to achieve activation of the noncanonical inflammasome ex vivo. Additionally, we transfected the PLXNC1 ligand SL4c-d in vivo and ex vivo to examine its effect on intracellular LPS response. Results: We found the neuronal guidance receptor PLXNC1 dampens the intracellular response to LPS by interacting with adenylate cyclase 4 (ADCY4) and protein kinase A activity, which in turn diminishes caspase-11 expression. The absence of PLXNC1 results in excessive inflammation marked by increased cytokine release, increased secondary organ injury and reduced sepsis survival in a murine sepsis model induced by CLP. Notably, administration of SL4c-d—peptide ligand of PLXNC1—reduces the inflammatory response during CLP-induced sepsis and improves survival. Conclusions: These results elucidate a previously unknown mechanism for PLXNC1 suppressing excessive noncanonical inflammasome activity and offer a new potential target for treatment of sepsis with its detrimental effects. [ABSTRACT FROM AUTHOR]