Activation and signaling of the p38 MAP kinase pathway

The discrepancies in amino acid sequence of the phosphate-binding loop lead to distinctive binding modes of a covalent inhibitor for MAP2K1 and MAP2K6: Structural insights for producing selective inhibitors

Mitogen-activated protein kinase kinase 6 (MAP2K6) plays a crucial role in activating the p38 MAPK pathway, and dysregulation of this pathway is associated with serious diseases including autoimmune diseases. 5Z-7-oxozeaenol (5Z7O), a covalent-binding inhibitor, inhibits MAP2K6 approximately ten times more strongly than MAP2K1, a common off-target kinase of MAP2K6. Here, we determined the crystal structure of the 5Z7O-MAP2K6 complex and carefully compared it with that of the 5Z7O-MAP2K1 complex previously reported. The binding orientation of 5Z7O is slightly different between the MAP2K1 and MAP2K6 complexes, resulting in different hydrogen-bond networks and thereby the higher potency of 5Z7O for MAP2K6 than MAP2K1. 5Z7O formed hydrogen bonds with the arginine residue in the catalytic HRD motif of MAP2K6 and asparagine residue in the solvent-accessible region but not with the corresponding residues of MAP2K1. Structural comparison implied that these differences in hydrogen bonding were attributable to differences in the phosphate-binding loop (P-loop) between MAP2K6 and MAP2K1. Molecular dynamics simulation revealed the above-mentioned and further structural features of MAP2K1 and MAP2K6. These distinct structural features are potentially useful for producing selective inhibitors for MAP2K1 and MAP2K6.

Exploring the double-edged role of cellular senescence in chronic liver disease for new treatment approaches

Cellular senescence is a fundamental yet complex defense mechanism that restricts excessive proliferation, maintains cellular homeostasis under various stress conditions-such as oncogenic activation and inflammation-and serves as a dynamic stress response program involved in development, aging, and immunity. Its reversibility depends on essential maintenance components. Cellular senescence is a "double-edged sword": on one hand, it limits the malignant proliferation of damaged cells, thereby preventing tumor development. However, by retaining secretory functions, senescent cells can also induce persistent changes in the microenvironment and disrupt homeostasis, leading to tissue inflammation, fibrosis, and carcinogenesis. Senescence plays a critical role in the pathogenesis of various chronic liver diseases, including chronic viral hepatitis, liver fibrosis, and hepatocellular carcinoma. It exerts a dual influence by facilitating immune evasion and inflammation in chronic viral hepatitis, modulating hepatic stellate cell activity in fibrosis, and reshaping the tumor microenvironment to accelerate hepatocarcinogenesis. This article reviews the characteristics of cellular senescence and its role in the pathogenesis of these chronic liver diseases while exploring potential treatment and prevention strategies. The aim is to provide a comprehensive reference for future clinical and research investigations into chronic liver disease.

7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN) attenuates inflammation and oxidative stress via MAPK, and Nrf2/HO-1 signaling in Traumatic brain injury

Traumatic brain injury (TBI) is an acquired neurological insult that has become a major cause of mortality.Hence, immediate and appropriate medical attention is essential. The present study investigated the neuroprotective effect of 7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid against a weight drop model of traumatic brain injury (TBI). During the in-vitro analysis, ECN demonstrated neuroprotective potential by remarkably improving the cell viability and also provided significant protection in case of nitric oxide-evoked oxidative stress in HT22 cells. The administration of ECN significantly improved the neurological severity score, and mechanical/periorbital allodynia following TBI, when compared with the TBI-group. The level of brain edema and blood-brain barrier (BBB) disruption were also significantly reduced by ECN treatment. ECN also restored constitutional changes in the protein/lipid profile; simultaneous with histological changes in the brain in contrast to the TBI-group. It significantly ameliorated neuronal loss and also minimized the intracerebral hemorrhages arising from traumatic insult. ECN exhibited potent anti-inflammatory effects, by altering the expression of extracellular-signal-regulated kinase (ERK), p38, and activating protein-1 (AP-1) proteins. It also exhibited antioxidant effects by increasing the production levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Furthermore, ECN also produced an anti-apoptotic effect by downregulation of caspase3 and upregulation of B-cell lymphoma 2 (Bcl-2). It also increased the levels of antioxidants while reducing the levels of oxidative stress and inflammatory markers in comparison to the TBI-group. In short, it was concluded that ECN exhibited protective anti-inflammatory, antioxidant, and anti-apoptotic effects against trauma-induced brain injury.

PAQR4: From spatial regulation of cell signaling to physiological homeostasis and diseases

Progestin and adipoQ receptor family member 4 (PAQR4) gene is a recently discovered seven-transmembrane protein-coding gene that belongs to the PAQR family. An increasing amount of evidence suggests that PAQR4 is upregulated in multiple tumors and participates in tumor progression and chemotherapy resistance via different signaling pathways; PAQR4 regulates cellular ceramide homeostasis by influencing sphingolipid metabolism and glycerol metabolism, and plays a significant role in adipose tissue remodeling. Meanwhile, it is known that the differential expression of PAQR4 is associated with the occurrence of various diseases and is a potential biomarker and therapeutic target. This article conducts a systematic review of the subcellular localization of PAQR4, its topological structure characteristics, and its functions in cancer occurrence, metabolic diseases, and fertility, and provides clues for the future research and translational application of PAQR4.

A gut bacterial supplement for Asian honey bee (Apis cerana) enhances host tolerance to nitenpyram: Insight from microbiota-gut-brain axis

The widespread use of neonicotinoid pesticides has severely impacted honey bees, driving population declines. Gut microbiota are increasingly recognized for their role in mitigating pesticide toxicity. This study evaluated the ability of Gilliamella sp. G0441, a core microbiome member of the Asian honey bee (Apis cerana), to confer resistance to the toxicity of a neonicotinoid nitenpyram. Newly emerged Asian honey bees were first colonized with gut microbiota in the source colony, then divided into four treatments: SS (fed sucrose solution throughout), SN (fed sucrose solution, then exposed to nitenpyram), GS (fed Gilliamella, then sucrose solution), and GN (fed Gilliamella, then exposed to nitenpyram), and their responses-mortality, food consumption, body weight, and sucrose sensitivity-were assessed. The protective effects of Gilliamella administration on the host were further validated using a microbiota-free bee model. Gilliamella supplementation significantly mitigated nitenpyram-induced appetite suppression, weight loss, impaired learning, and gut microbiota disruption. Mechanistic analyses revealed that nitenpyram disrupted brain metabolism via the intestinal MAPK pathway, reducing ascorbate and aldarate metabolism. Prophylactic Gilliamella treatment reversed these effects, restored metabolic balance, and modulated esterase E4 expression, enhancing pesticide resistance. This study underscores Gilliamella's vital role in honey bee resilience to neonicotinoids, offering insights into the microbiota-gut-brain axis (MGBA) as a pathway for enhancing pesticide tolerance and ecological health.

Molecular mechanisms and consequences of TDP-43 phosphorylation in neurodegeneration

Increased phosphorylation of TDP-43 is a pathological hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the regulation and roles of TDP-43 phosphorylation remain incompletely understood. A variety of techniques have been utilized to understand TDP-43 phosphorylation, including kinase/phosphatase manipulation, phosphomimic variants, and genetic, physical, or chemical inducement in a variety of cell cultures and animal models, and via analyses of post-mortem human tissues. These studies have produced conflicting results: suggesting incongruously that TDP-43 phosphorylation may either drive disease progression or serve a neuroprotective role. In this review, we explore the roles of regulators of TDP-43 phosphorylation including the putative TDP-43 kinases c-Abl, CDC7, CK1, CK2, IKKβ, p38α/MAPK14, MEK1, TTBK1, and TTBK2, and TDP-43 phosphatases PP1, PP2A, and PP2B, in disease. Building on recent studies, we also examine the consequences of TDP-43 phosphorylation on TDP-43 pathology, especially related to TDP-43 mislocalisation, liquid-liquid phase separation, aggregation, and neurotoxicity. By comparing conflicting findings from various techniques and models, this review highlights both the discrepancies and unresolved aspects in the understanding of TDP-43 phosphorylation. We propose that the role of TDP-43 phosphorylation is site and context dependent, and includes regulation of liquid-liquid phase separation, subcellular mislocalisation, and degradation. We further suggest that greater consideration of the normal functions of the regulators of TDP-43 phosphorylation that may be perturbed in disease is warranted. This synthesis aims to build towards a comprehensive understanding of the complex role of TDP-43 phosphorylation in the pathogenesis of neurodegeneration.

Co-exposure to ozone and polystyrene nanoplastic exacerbates cognitive impairment and anxiety-like behavior by regulating neuronal pyroptosis in mice

Ozone (O3) and nanoplastics (NPs) are pervasive environmental pollutants that frequently co-occur in our heavily industrialized era. While it has been documented that exposure to O3 or NPs individually has neurotoxic effects, studies investigating their combined impact and the hazardous mechanisms resulting from co-exposure are limited. In this study, we established a mouse model co-exposure to polystyrene nanoparticles (PS-NPs) and O3, focusing on the prefrontal cortex (PFC), a brain region crucial for cognition and emotion. We examined the effects of O3 and PS-NPs on behavioral changes related to learning, memory, and anxiety, employing transcriptome sequencing alongside molecular and histopathological methods. Our findings indicate that combined exposure to O3 and PS-NPs disrupts the integrity of the blood-brain barrier, reducing Claudin 5 expression and leading to increased accumulation of PS-NPs in the PFC. Transcriptome sequencing demonstrated the involvement of the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway and oxidative stress in the pathological changes observed in the PFC. Through immunohistochemical and immunofluorescence analysis, we observed enhanced microglial activation, which correlates with increased production of inflammatory factors. Additionally, western blot and immunofluorescence co-labeling analyses revealed elevated expression levels of GSDMD-N, caspase-1, IL-1β, and IL-18 proteins, which are associated with neuronal pyroptosis. Finally, immunofluorescence co-labeling confirmed that the activation of the p38 MAPK pathway in neurons is involved in co-exposure-induced pyroptosis. Meanwhile, N-Acetylcysteine (NAC), a common antioxidant, can alleviate neuroinflammation and neuronal pyroptosis in the PFC, and it rescued the cognitive deficits and anxiety-like behaviors observed in the co-exposed mice. Our study illustrates that co-exposure to O3 and NPs can aggravate damage to the blood-brain barrier and elevate oxidative stress levels in the PFC, thereby increasing the occurrence of neuroinflammation and may mediate neuronal pyroptosis through activation of the p38 MAPK pathway, ultimately contributing to neurobehavioral toxicity.

Rutin Attenuates Distraction Spinal Cord Injury by Inhibiting Microglial Inflammation Through Downregulation of P38 MAPK/NF-κB/STAT3 Pathway

Distraction spinal cord injury (DSCI) is a severe complication following scoliosis correction surgery, for which there are currently no effective clinical treatments. This study aims to evaluate the inhibitory effects of rutin, a natural product, on inflammation in DSCI and to investigate the underlying mechanisms. In vitro, microglial cells were exposed directly to rutin to assess its ability to inhibit lipopolysaccharide (LPS)-induced inflammation. In rats with DSCI, the inhibitory effect of rutin on DSCI was evaluated using behavioral tests. mRNA sequencing was performed on spinal cord tissues to elucidate the mechanism of rutin's action. Rutin significantly suppressed the LPS-induced increase in inflammatory factors in microglial cells. In DSCI rats treated with rutin, scores in the Basso-Beattie-Bresnahan (BBB) were significantly improved. The mechanism of rutin's action was found to be related to its ability to reduce inflammatory infiltration in spinal cord tissue, protecting neurons from apoptosis and microstructural demyelination. Through assays of transcriptomic differentially expressed genes (DEGs), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and RT-qPCR validation of the top DEGs, MAPK13 (also known as P38 MAPK) was finally identified as the key target gene in promoting DSCI development. Further molecular docking analysis indicated an interaction between rutin and P38 MAPK, supporting the rutin's action and the underlying mechanism in anti-inflammation. In conclusion, rutin effectively inhibited the development of DSCI in rats. The mechanism of rutin's action was associated with its activity in blocking the P38 MAPK/NF-κB/STAT3 pathway in the microglial cells of spinal cord. Rutin could be developed as a potential anti-DSCI drug for clinical applications.

During high salt treatment myeloid p38α/MAPK fosters osteoclast activity and inflammatory macrophage responses promoting orthodontic tooth movement

Introduction

During orthodontic tooth movement, sterile inflammatory processes and alveolar bone resorption occur in the periodontal ligament, involving myeloid cells such as macrophages and osteoclasts. The myeloid p38α/MAPK (mitogen-activated protein kinase) not only regulates the inflammatory response of macrophages and osteoclast differentiation but also the activation of the osmoprotective transcription factor NFAT5 (nuclear factor of activated T cells 5) under high-salt conditions. Therefore, this study aims to investigate the relative role of myeloid p38α/MAPK in orthodontic tooth movement as a function of extracellular salt content.

Material and methods

Macrophages and osteoclasts were differentiated from the bone marrow of mice lacking p38α/MAPK expression in myeloid cells (p38α Δmyel) and controls for RNA analysis and calcium phosphate resorption assay. Controls and p38α Δmyel mice were fed a low or a high salt diet for a total of two weeks. One week after the start of the diet, an elastic band was inserted between the first and second molar to induce orthodontic tooth movement. Atomic absorption spectrometry was used to assess the sodium balance of the jaw bone tissue. RNA was isolated from the periodontium of the first molar, osteoclast numbers and extent of orthodontic tooth movement were assessed.

Results

Nfat5 mRNA was increased in macrophages and osteoclasts in vitro and in the periodontium in vivo after high salt treatment in control mice but not in p38α Δmyel mice. While there was no salt effect on interleukin-6 (Il6) gene expression, prostaglandin endoperoxide synthase-2 (Ptgs2) mRNA was upregulated in control but not in p38α Δmyel mice in vitro and in vivo. p38α/MAPK deletion increased osteoclast numbers after low and high salt diet. Of note, deletion of p38α/MAPK elevated osteoclast activity under control salt conditions but reduced osteoclast activity under high salt conditions. High-salt diet resulted in increased sodium ion deposition in the jaw of both genotypes, while tooth movement was only increased in control mice. In p38α Δmyel mice, high salt diet reduced the extent of orthodontic tooth movement, which could be explained by the reduced bone resorption of osteoclasts.

Conclusion

We conclude that myeloid p38α/MAPK promotes macrophage Ptgs2 expression and osteoclast activity in response to extracellular salt levels, thereby supporting orthodontic tooth movement.

Protein Kinases as Mediators for miRNA Modulation of Neuropathic Pain

Neuropathic pain is a chronic condition resulting from injury or dysfunction in the somatosensory nervous system, which leads to persistent pain and a significant impairment of quality of life. Research has highlighted the complex molecular mechanisms that underlie neuropathic pain and has begun to delineate the roles of microRNAs (miRNAs) in modulating pain pathways. miRNAs, which are small non-coding RNAs that regulate gene expression post-transcriptionally, have been shown to influence key cellular processes, including neuroinflammation, neuronal excitability, and synaptic plasticity. These processes contribute to the persistence of neuropathic pain, and miRNAs have emerged as critical regulators of pain behaviors by modulating signaling pathways that control pain sensitivity. miRNAs can influence neuropathic pain by targeting genes that encode protein kinases involved in pain signaling. This review focuses on miRNAs that have been demonstrated to modulate neuropathic pain behavior through their effects on protein kinases or their immediate upstream regulators. The relationship between miRNAs and neuropathic pain behaviors is characterized as either an upregulation or a downregulation of miRNA levels that leads to a reduction in neuropathic pain. In the case of miRNA upregulation resulting in an alleviation of neuropathic pain behaviors, protein kinases exhibit a positive correlation with neuropathic pain, whereas decreased protein kinase levels correlate with diminished neuropathic pain behaviors. The only exception is GRK2, which shows an inverse correlation with neuropathic pain. In the case of miRNA downregulation resulting in a reduction in neuropathic pain behaviors, protein kinases display mixed relationships to neuropathic pain, with some kinases exhibiting positive correlation, while others exhibit negative correlation. By exploring how protein kinases mediate miRNA modulation of neuropathic pain, valuable insight may be gained into the pathophysiology of neuropathic pain, offering potential therapeutic targets for developing more effective strategies for pain management.

Mechanoreceptor Piezo1 channel-mediated interleukin expression in conjunctival epithelial cells: Linking mechanical stress to ocular inflammation

PURPOSE

Mechanical stress on the ocular surface, such as from eye-rubbing, has been reported to lead to inflammation and various ocular conditions. We hypothesized that the mechanosensitive Piezo1 channel in the conjunctival epithelium contributes to the inflammatory response at the ocular surface after receiving mechanical stimuli.

METHODS

Human conjunctival epithelial cells (HConjECs) were treated with Yoda1, a Piezo1-specific agonist, and various allergens to measure cytokine expression levels using qRT-PCR. Piezo1 activation-induced intracellular signaling pathways were also investigated by Western blot. Mechanical stretching experiments were conducted to simulate Piezo1 activation in HConjECs. Specificity of Piezo1 was confirmed by PIEZO1 knockdown and GsMTx4. In in vivo studies, using immunohistochemistry, rats were administered Yoda1 eye drops to examine the inflammatory response in the conjunctiva and Piezo1-induced signaling activation.

RESULTS

HConjECs expressed functional Piezo1 channel which was the dominant mechanoreceptor among putative channels and whose activation significantly increased IL-6 and IL-8 expression through the p38 MAPK-CREB pathway. Piezo1-induced [Ca2+]i elevation was crucial for the production of IL-6. The Yoda1-induced inflammatory responses were blocked by PIEZO1 knockdown. Mechanical stretching mimicked these effects, which were suppressed by GsMTx4. In vivo, Yoda1 administration led to increased phospho-p38 MAPK, phospho-CREB, and IL-6 in the rat conjunctival epithelium, with significant neutrophil infiltration.

CONCLUSION

Mechanical stress-induced Piezo1 channel activation in conjunctival epithelial cells can cause ocular inflammation by upregulating pro-inflammatory cytokines via the p38 MAPK-CREB pathway and promoting neutrophil infiltration. These findings suggest that mechanical stimuli on ocular surface tissues are significant risk factors for ocular inflammation.

CBLB Regulates MAPK-P38 Pathway via MAP3K9 Ubiquitination to Inhibit GBM Cell Invasion and Migration

Glioma cells exhibit high invasiveness and have the ability to evade surgical resection, radiotherapy, and chemotherapy, which are major factors contributing to the challenges in effective treatment and recurrence. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification, significantly contributing to the aggressive progression of glioblastoma (GBM). This study identified the E3 ubiquitin ligase CBLB as a crucial and abnormally regulated component of the UPS in GBM, noting its significant downregulation compared to normal brain tissue and its negative correlation with malignant phenotypes and poor prognosis. Experimental studies, both in vitro and in vivo, have shown that CBLB can inhibit the migration and invasion of GBM cells. Mechanistically, CBLB directly interacts with MAP3K9 through its RING domain, leading to K48-K63-linked polyubiquitination at the Lys 193 site, thereby promoting MAP3K9 proteasomal-mediated degradation. MAP3K9 downregulation suppresses MAPK-P38 pathway activation. This study identifies CBLB as a tumor suppressor that modulates the MAPK-P38 signaling pathway by promoting the polyubiquitination and degradation of MAP3K9, offering a new therapeutic approach for GBM treatment.

GPR35 prevents osmotic stress induced cell damage

GPR35 is an orphan G-protein coupled receptor that has been implicated in the development of cancer. GPR35 regulates the Na+/K+-ATPase's pump and signalling function. Here we show GPR35's critical role in ion flux that in turn controls cellular osmotic pressure and Na+-dependent transport in HepG2 and SW480 cells. GPR35 deficiency results in increased levels of intracellular Na+, osmotic stress and changes in osmolytes leading to increased cells size and decreased glutamine import in vitro and in vivo. The GPR35-T108M risk variant, which increases risk for primary sclerosing cholangitis and inflammatory bowel disease, leads to lower intracellular Na+ levels, and enhanced glutamine uptake. High salt diet (HSD) in wildtype mice resembles the intestinal epithelial phenotype of their Gpr35-/- littermates with decreased Goblet cell size and numbers. This indicates that GPR35's regulation of the Na+/K+-ATPase controls ion homeostasis, osmosis and Na+-dependent transporters.

Exploring the anti-anaphylaxis potential of natural products: A Review

Allergies are a common health issue affecting many people around the world, especially in developed countries. They occur when the immune system overreacts to substances that are usually harmless. Some common allergic conditions include asthma, sinus infections, skin rashes, food allergies, hay fever, severe allergic reactions, eczema, swelling, and reactions to medications or insect stings. The causes of these allergies are complex and often linked to genetics, which can lead to heightened immune responses known as atopy. Throughout history, plant extracts have been used for various purposes, including medicine and food. In addition, their bioactive compounds show a wide range of beneficial effects, such as reducing allergic reactions, fighting oxidative stress, mast cell stabilizers, and lowering inflammation, highlighting their potential for treating various health conditions. Flavonoids and phenolic compounds are commonly used in anaphylaxis for their potent anti-inflammatory action. This review aims to promote the use of natural products as potential treatments for anaphylaxis. In addition, the discovery of new drugs derived from natural sources holds significant promise for the management of anaphylaxis.

Sinapic Acid Ameliorates Doxorubicin-Induced Cardiotoxicity in H9c2 Cardiomyoblasts by Inhibiting Oxidative Stress Through Activation of the Nrf2 Signaling Pathway

The use of doxorubicin (Dox) is restricted because of its cardiotoxicity, which poses a significant mortality risk for cancer patients, despite being a highly effective antibiotic for treating various types of cancer. Therefore, identifying substances or developing preventive strategies against Dox-induced cardiotoxicity is crucial. This study was conducted to determine whether sinapic acid (SA), a phenolic compound with a range of pharmacological effects, could protect against Dox-induced cardiotoxicity in H9c2 cardiomyoblasts. To investigate the preventive effect of SA, H9c2 cardiomyoblasts treated with Dox were pretreated with SA at various concentrations. SA effectively rescued the cells from Dox-induced cardiotoxicity. Additionally, SA significantly reduced oxidative stress by inhibiting mitochondrial dysfunction and endoplasmic reticulum stress. SA also suppressed the expression of MAPK proteins. As for the underlying mechanism of SA's protective effect against Dox-induced cardiotoxicity, SA activated nuclear factor erythroid-2-related factor (Nrf2) by facilitating its movement from the cytosol to the nucleus and increasing the expression of its target antioxidative genes. In summary, this study demonstrated that SA protects H9c2 cardiomyoblasts from Dox-induced cardiotoxicity by inhibiting oxidative stress by the activation of Nrf2-related signaling pathway. Our findings enhance the development of therapeutic strategies to mitigate cardiac toxicity caused by Dox, highlighting the potential antioxidant effect of SA in Dox-treated H9c2 cardiomyoblasts.

Splenic TNF-α signaling potentiates the innate-to-adaptive transition of antiviral NK cells

Natural killer (NK) cells possess both innate and adaptive features. Here, we investigated NK cell activation across tissues during cytomegalovirus infection, which generates antigen-specific clonal expansion and long-lived memory responses. Longitudinal tracking and single-cell RNA sequencing of NK cells following infection revealed enhanced activation in the spleen, as well as early formation of a CD69lo precursor population that preferentially gave rise to adaptive NK cells. Splenic NK cells demonstrated heightened tumor necrosis factor alpha (TNF-α) signaling and increased expression of the receptor TNFR2, which coincided with elevated TNF-α production by splenic myeloid cells. TNFR2-deficient NK cells exhibited impaired interferon gamma (IFN-γ) production and expansion. TNFR2 signaling engaged two distinct nuclear factor κB (NF-κB) signaling arms-innate effector NK cell responses required canonical NF-κB signaling, whereas non-canonical NF-κB signaling enforced differentiation of CD69lo adaptive NK cell precursors. Thus, NK cell priming in the spleen during viral infection promotes an innate-to-adaptive transition, providing insight into avenues for generating adaptive NK cell immunity across diverse settings.

G protein-coupled oestrogen receptor regulates branched-chain amino acid metabolism through c-Jun N-terminal kinase

Branched-chain amino acids (BCAA) are essential requirements for overall protein turnover, signalling and energy balance, and dysregulation of their metabolic pathway has been associated with many pathophysiological events. Despite the importance of BCAA in human health, our understanding of their metabolic regulation is limited. Here, we present evidence that G protein-coupled oestrogen receptor (GPER) activation inhibits the key BCAA metabolic regulatory enzyme branched-chain α-keto acid dehydrogenase complex (BCKDH) by phosphorylating S293. Inhibition of BCKDH results in leucine, isoleucine and valine accumulation in cells. Interestingly, GPER did not alter the levels of the kinase BCKDK and the phosphatase PPM1K, which regulate BCKDH activity, but activated MAPK signalling. Using gene silencing, we identified that JNK intercedes GPER-mediated BCKDH inhibition. Together, our results demonstrate that GPER inhibits BCAA metabolism through JNK signalling.

Pharmacological Enhancement of Adult Hippocampal Neurogenesis Improves Behavioral Pattern Separation in Young and Aged Male Mice

Background

Impairments in behavioral pattern separation (BPS)-the ability to distinguish between similar contexts or experiences-contribute to memory interference and overgeneralization seen in many neuropsychiatric conditions, including depression, anxiety, posttraumatic stress disorder, dementia, and age-related cognitive decline. Although BPS relies on the dentate gyrus and is sensitive to changes in adult hippocampal neurogenesis, its significance as a pharmacological target has not been tested.

Methods

In this study, we applied a human neural stem cell high-throughput screening cascade to identify compounds that increase human neurogenesis. One compound with a favorable profile, RO6871135, was then tested in young and aged mice for effects on BPS and anxiety-related behaviors.

Results

Chronic treatment with RO6871135 (7.5 mg/kg) increased adult hippocampal neurogenesis and improved BPS in a fear discrimination task in both young and aged mice. RO6871135 treatment also lowered innate anxiety-like behavior, which was more apparent in mice exposed to chronic corticosterone. Ablation of adult hippocampal neurogenesis by hippocampal irradiation supported a neurogenesis-dependent mechanism for RO6871135-induced improvements in BPS. To identify possible mechanisms of action, in vitro and in vivo kinase inhibition and chemical proteomics assays were performed. These tests indicated that RO6871135 inhibited CDK8, CDK11, CaMKIIa, CaMKIIb, MAP2K6, and GSK-3β. An analog compound also demonstrated high affinity for CDK8, CaMKIIa, and GSK-3β.

Conclusions

These studies demonstrate a method for empirical identification and preclinical testing of novel neurogenic compounds that can improve BPS and point to possible novel mechanisms that can be interrogated for the development of new therapies to improve specific endophenotypes such as impaired BPS.

Development of a biomarker panel for cell characterization intended for cultivated meat

Cultivated meat has in recent years been suggested as a sustainable alternative to produce meat at large-scale. Several aspects of cultivated meat production have demonstrated significant progress. However, there are still many questions regarding the cell culture, media composition, and the production itself to be answered and optimized. Finding good starter cell populations is a challenge to address and requires robust tools to characterize the cell populations. Detailed analysis is required to identify each type of cell within the skeletal muscle niche leads to optimized cultivated meat production at large-scale. In this study, we developed a set of biomarkers, using digital droplet PCR (ddPCR) and Immunofluorescence (IF) staining, to identify specific cell types within a heterogeneous cell population isolated from skeletal muscle tissue. We showed that combining Neural Cell Adhesion Molecule (NCAM), Calponin 1 (CNN1), and Fibronectin (FN), can be a powerful approach to predict the growth of skeletal myotubes, smooth muscle mesenchymal cells (SMMCs), and myofibroblasts, respectively. Moreover, early cell-cell interactions of fibroblastic cells were observed to be triggered through thin actin filaments containing CNN1 protein, to form, subsequently, myofibroblast networks. Besides, Myogenic Differentiation 1 (MyoD) is the key marker to detect skeletal muscle growth, whereas Myogenic Factor 5 (MyF5) can be expressed in myogenic and non-myogenic cells. MyF5 was detected at differentiation stages within the myotube nuclei, suggesting an unknown role during myotube formation.

Optogenetics with Atomic Precision─A Comprehensive Review of Optical Control of Protein Function through Genetic Code Expansion

Conditional control of protein activity is important in order to elucidate the particular functions and interactions of proteins, their regulators, and their substrates, as well as their impact on the behavior of a cell or organism. Optical control provides a perhaps optimal means of introducing spatiotemporal control over protein function as it allows for tunable, rapid, and noninvasive activation of protein activity in its native environment. One method of introducing optical control over protein activity is through the introduction of photocaged and photoswitchable noncanonical amino acids (ncAAs) through genetic code expansion in cells and animals. Genetic incorporation of photoactive ncAAs at key residues in a protein provides a tool for optical activation, or sometimes deactivation, of protein activity. Importantly, the incorporation site can typically be rationally selected based on structural, mechanistic, or computational information. In this review, we comprehensively summarize the applications of photocaged lysine, tyrosine, cysteine, serine, histidine, glutamate, and aspartate derivatives, as well as photoswitchable phenylalanine analogues. The extensive and diverse list of proteins that have been placed under optical control demonstrates the broad applicability of this methodology.

Nitroxidative Stress, Cell-Signaling Pathways, and Manganese Porphyrins: Therapeutic Potential in Neuropathic Pain

Neuropathic pain, a debilitating condition arising from somatosensory system damage, significantly impacts quality of life, leading to anxiety, self-mutilation, and depression. Oxidative and nitrosative stress, an imbalance between reactive oxygen and nitrogen species (ROS/RNS) and antioxidant defenses, plays a crucial role in its pathophysiology. While reactive species are essential for physiological functions, excessive levels can cause cellular component damage, leading to neuronal dysfunction and pain. This review highlights the complex interactions between reactive species, antioxidant systems, cell signaling, and neuropathic pain. We discuss the physiological roles of ROS/RNS and the detrimental effects of oxidative and nitrosative stress. Furthermore, we explore the potential of manganese porphyrins, compounds with antioxidant properties, as promising therapeutic agents to mitigate oxidative stress and alleviate neuropathic pain by targeting key cellular pathways involved in pain. Further research is needed to fully understand their therapeutic potential in managing neuropathic pain in human and non-human animals.

Downregulation of AQP9 Ameliorates NLRP3 Inflammasome-Dependent Inflammation and Pyroptosis in Crohn's Disease by Inhibiting the p38 MAPK Signaling Pathway

Crohn's disease (CD), a complex gastrointestinal disorder, can be attributed to a combination of genetic factors, immune system dysfunction, and environmental triggers. Aquaporin 9 (AQP9) has been implicated in immunoregulation and inflammation in various conditions, yet its function in CD remains unclear. Herein, we investigated the contribution of AQP9 to CD pathogenesis and its impact on inflammation and pyroptosis. Bioinformatic analysis showed a significant increase in AQP9 expression (above 2.5-fold change) in CD patients compared to controls. In vitro experiments using human colonic epithelial cells (HT-29) demonstrated that AQP9 inhibition attenuated lipopolysaccharide (LPS)-induced cell damage, inflammatory cytokine secretion, and pyroptosis. Mechanistically, AQP9 silencing suppressed NLRP3 inflammasome activation, suggesting a role in regulating pyroptosis. AQP9 silencing inhibited p38 MAPK phosphorylation, indicating a direct involvement in modulating this inflammatory pathway. Furthermore, our findings indicate that AQP9 exacerbates inflammation and pyroptosis via activating the p38 MAPK signaling pathway, known to contribute to CD pathogenesis. In vivo studies using a murine model of CD-like colitis revealed that AQP9 inhibition led to about 45% reduction in colitis severity scores and about 30% decrease in the production of inflammatory cytokine by inactivating NLRP3 inflammasome and the p38 MAPK signaling. To sum up, our study highlights the involvement of AQP9 in CD pathogenesis through modulation of inflammation and pyroptosis via the NLRP3 inflammasome and p38 MAPK signaling pathway. Targeting AQP9 may offer a promising therapeutic approach for CD by suppressing inflammatory responses and preventing tissue damage.

The Shh-p38-NFATc1 signaling pathway is essential for osteoclastogenesis during tooth eruption

Tooth eruption, a critical stage in tooth development, is related to osteoclastogenesis. Intraperitoneal injection of Shh agonists into neonatal mice promoted tooth eruption at postnatal day (PN) 15, whereas treatment with the Shh inhibitor (LDE225) suppressed this process. When RAW264.7 osteoclast precursor cells were treated with RANKL, NFATc1 translocated from the cytoplasm to the nucleus and induced cell differentiation into TRAP+ osteoclasts; this process was activated by Shh but inhibited by LDE225. Treating RAW264.7 cells with the p38 inhibitor, BIRB796, also inhibited NFATc1 nuclear localization. p-p38 expression in the alveolar bone of PN3 and PN5 mice was decreased by treatment with LDE225, and RAW264.7 cell differentiation was reduced by BIRB796, regardless of treatment with Shh. Furthermore, Shh activated p38 signaling pathway in RAW264.7 cells, while p38 phosphorylation was reduced by LDE225, which ultimately inhibited osteoclast precursor differentiation. Therefore, we concluded that Shh promotes osteoclast precursor differentiation via the p38-NFATc1 signaling pathway.

Inhibition of Endoplasmic Reticulum Stress Cooperates with SLC7A11 to Promote Disulfidptosis and Suppress Tumor Growth upon Glucose Limitation

Disulfidptosis is a newly discovered type of regulated cell death triggered by disulfide bond accumulation and NADPH (nicotinamide adenine dinucleotide phosphate) depletion due to glucose deprivation. However, the regulatory mechanisms involving additional cellular circuits remain unclear. Excessive disulfide bond accumulation can impair endoplasmic reticulum (ER) homeostasis and activate the ER stress response. In this study, we found that SLC7A11-mediated disulfidptosis upon glucose deprivation is accompanied by ER stress induction. Pharmacological inhibition of SLC7A11-mediated cystine uptake or cystine withdrawal not only blocks disulfidptosis under glucose starvation but also suppresses the ER stress response, indicating a close link between these processes. Moreover, inhibitors targeting the ER stress response promote disulfidptosis, while ER stress inducers suppress glucose starvation-induced disulfidptosis in SLC7A11-high-expressing cells, suggesting a protective role for ER stress during disulfidptosis. Similar effects are observed in cells treated with glucose transporter inhibitors (GLUTi). Finally, combined treatment with ER stress inhibitors and GLUTi significantly suppresses tumor growth both in vitro and in vivo by inducing disulfide stress and subsequent disulfidptosis. In summary, these findings reveal a novel role for ER stress in regulating disulfidptosis and provide theoretical insights into the potential application of GLUTi and ER stress inhibitors in cancer therapy.

Opposing roles of p38α-mediated phosphorylation and PRMT1-mediated arginine methylation in driving TDP-43 proteinopathy

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder typically characterized by insoluble inclusions of hyperphosphorylated TDP-43. The mechanisms underlying toxic TDP-43 accumulation are not understood. Persistent activation of p38 mitogen-activated protein kinase (MAPK) is implicated in ALS. However, it is unclear how p38 MAPK affects TDP-43 proteinopathy. Here, we show that p38α MAPK inhibition reduces pathological TDP-43 phosphorylation, aggregation, cytoplasmic mislocalization, and neurotoxicity. Remarkably, p38α MAPK inhibition mitigates aberrant TDP-43 phenotypes in diverse ALS patient-derived motor neurons. p38α MAPK phosphorylates TDP-43 at pathological S409/S410 and S292, which reduces TDP-43 liquid-liquid phase separation (LLPS) but allows pathological TDP-43 aggregation. Moreover, we establish that PRMT1 methylates TDP-43 at R293. Importantly, S292 phosphorylation reduces R293 methylation, and R293 methylation reduces S409/S410 phosphorylation. Notably, R293 methylation permits TDP-43 LLPS and reduces pathological TDP-43 aggregation. Thus, strategies to reduce p38α-mediated TDP-43 phosphorylation and promote PRMT1-mediated R293 methylation could have therapeutic utility for ALS and related TDP-43 proteinopathies.

Fibrotic Changes in Rhegmatogenous Retinal Detachment

Rhegmatogenous retinal detachment (RRD) is a sight-threatening condition involving retinal detachment and the accumulation of fluid in the subretinal space. Proliferative vitreoretinopathy (PVR) is a pathologic complication that develops after RRD surgery, and approximately 5-10% of RRD cases develop post-operative PVR. Prolonged inflammation in the wound healing process, epithelial-mesenchymal transition (EMT), retinal pigment epithelial (RPE) cell migration and proliferation, and epiretinal, intraretinal, and subretinal fibrosis are typical in the formation of PVR. RPE cells undergo EMT and become fibroblast-like cells that migrate to the retina and vitreous, promoting PVR formation. Fibroblasts transform into myofibroblasts, which promote fibrosis by overproducing the extracellular matrix (ECM). RPE cells, fibroblasts, glial cells, macrophages, T lymphocytes, and increased ECM production form contractile epiretinal membranes. Cytokine release, complement activation, RPE cells, glial cells, and endothelial cells are all involved in retinal immune responses. Normally, wounds heal within 4 to 6 weeks, including hemostasis, inflammation, proliferation, and remodeling phases. Properly initiated inflammation, complement activation, and the function of neutrophils and glial cells heal the wound in the first stage. In a retinal wound, glial cells proliferate and fill the injured area. Gliosis tries to protect the neurons and prevent damage, but it becomes harmful when it causes scarring. If healing is complicated, prolonged inflammation leads to pathological fibrosis. Currently, there is no preventive treatment for the formation of PVR, and it is worth studying in the future.

PLK3 weakens antioxidant defense and inhibits proliferation of porcine Leydig cells under oxidative stress

Aging is characterized by cellular degeneration and impaired physiological functions, leading to a decline in male sexual desire and reproductive capacity. Oxidative stress (OS) lead to testicular aging by impairing the male reproductive system, but the potential mechanisms remain unclear. In the present study, the functional status of testicular tissues from young and aged boars was compared, and the transcriptional responses of Leydig cells (LCs) to hydrogen peroxide (H2O2)-induced senescence were explored, revealing the role of OS in promoting aging of the male reproductive system. 601 differentially expressed genes (DEGs) associated with OS, cell cycle regulation, and intracellular processes were identified. These DEGs were significantly enriched in critical aging pathways, including the p53 signaling pathway, autophagy, and cellular senescence. Protein-protein interaction (PPI) network analysis unveiled 15 key genes related to cell cycle and DNA replication, with polo-like kinase 3 (PLK3) exhibiting increased expression under OS. In vitro, PLK3 knockdown significantly enhanced the viability and antioxidant capacity of LCs under OS. This study deepens our understanding of how LCs respond to OS and provides new therapeutic targets for enhancing cellular resistance to oxidative damage and promoting tissue health.

Signalling pathways involved in urotensin II induced ventricular myocyte hypertrophy

Sustained pathologic myocardial hypertrophy can result in heart failure(HF); a significant health issue affecting a large section of the population worldwide. In HF there is a marked elevation in circulating levels of the peptide urotensin II(UII) but it is unclear whether this is a result of hypertrophy or whether the high levels contribute to the development of hypertrophy. The aim of this study is to investigate a role of UII and its receptor UT in the development of cardiac hypertrophy and the signalling molecules involved. Ventricular myocytes isolated from adult rat hearts were treated with 200nM UII for 48hours and hypertrophy was quantified from measurements of length/width (L/W) ratio. UII resulted in a change in L/W ratio from 4.53±0.10 to 3.99±0.06; (p<0.0001) after 48hours. The response is reversed by the UT-antagonist SB657510 (1μM). UT receptor activation by UII resulted in the activation of ERK1/2, p38 and CaMKII signalling pathways measured by Western blotting; these are involved in the induction of hypertrophy. JNK was not involved. Moreover, ERK1/2, P38 and CaMKII inhibitors completely blocked UII-induced hypertrophy. Sarcoplasmic reticulum (SR) Ca2+-leak was investigated in isolated myocytes. There was no significant increase in SR Ca2+-leak. Our results suggest that activation of MAPK and CaMKII signalling pathways are involved in the hypertrophic response to UII. Collectively our data suggest that increased circulating UII may contribute to the development of left ventricular hypertrophy and pharmacological inhibition of the UII/UT receptor system may prove beneficial in reducing adverse remodeling and alleviating contractile dysfunction in heart disease.

MiR-4298 and lncKRTAP5-6-3 regulated Cathepsin D expression through ERK-MAPK signaling pathway in chronic UVB-damaged HaCaT cells

Objective

MiRNAs and lncRNAs are important regulators in the process of skin photoaging. In this study, we investigated the expression changes and interactions between miR4298 and lncKRTAP5-6-3 in chronically UVB-damaged human keratinocyte cell line (HaCaT) cells and explored miR4298-MAPK/ERK signaling pathway-Cathepsin D-lncKRTAP5-6-3 mechanisms in photoaging cells.

Methods

HaCaT cells were irradiated with 12 mJ/cm2 UVB once a day for 7 days. miR-4298 mimics and miR-4298 inhibitors were transfected into HaCaT cells by lipo3000 transfection reagent, and the HaCaT cells were divided into three groups: blank control group; UVB-damaged group; and UVB damage+miR-4298 regulation (overexpression or inhibition) group. The expression levels of miR4298 and lncKRTAP5-6-3 were quantitatively analyzed using RT-PCR, while the expression of Cathepsin D and MAPK/ERK signaling pathway proteins was detected using Western blot.

Results

After 7 consecutive days of UVB irradiation, the expression of miR-4298 decreased by 0.64 ± 0.06 (P < 0.001) compared to the un-irradiated HaCaT cells, and the expression of the KRTAP5-6-3 decreased by 0.80 ± 0.13 (P < 0.001) compared to the control group. The expression of p-ERK signaling was increased by 0.9437 ± 0.1186 (P < 0.0001), and Cathepsin D was decreased by 0.6163 ± 0.075 (P < 0.0001). In HaCaT cells transfected with miR-4298 mimics and then irradiated by UVB for 7 days, the expression of lncKRTAP5-6-3 was increased to 0.5114 ± 0.1438 (P < 0.05)-fold, and the phosphorylation level of ERK signaling was decreased by 0.3880 ± 0.1185 (P < 0.01), while Cathepsin D expression was increased by 0.2617 ± 0.0749 (P < 0.0001) compared to the UVB-damaged group. In HaCaT cells transfected with miR-4298 inhibitors and then irradiated by UVB for 7 days, lncKRTAP5-6-3 was decreased by 0.1697 ± 0.1383, the phosphorylation level of ERK signaling was increased by 1.096 ± 0.7836 (P < 0.05), while Cathepsin D expression was decreased by 0.05197 ± 0.24827 compared to the UVB-damaged group.

Conclusion

The synergistic effects of miR4298 and lncKRTAP5-6-3 play important roles in chronic UVB-damaged HaCaT cells by regulating the MAPK/ERK signaling pathway and Cathepsin D expression. This study presents novel targets for intervening in chronic ultraviolet damage (photoaging) skin and UV-related dermatoses.

Neuroinflammation mediates the progression of neonate hypoxia-ischemia brain damage to Alzheimer's disease: a bioinformatics and experimental study

Background

Traumatic brain injury (TBI) can generally be divided into focal damage and diffuse damage, and neonate Hypoxia-Ischemia Brain Damage (nHIBD) is one of the causes of diffuse damage. Patients with nHIBD are at an increased risk of developing Alzheimer's disease (AD). However, the shared pathogenesis of patients affected with both neurological disorders has not been fully elucidated.

Purpose

We here aim to identify the shared molecular signatures between nHIBD and AD. We used an integrated analysis of the cortex gene expression data, targeting differential expression of genes related to the mechanisms of neurodegeneration and cognitive impairment following traumatic brain injury.

Methods

The gene expression profiles of Alzheimer's disease (GSE203206) and that of Neonate Hypoxia-Ischemia Brain Damage (GSE23317) were obtained from the Gene Expression Omnibus (GEO) database. After identifying the common differentially expressed genes (DEGs) of Alzheimer's disease and neonate Hypoxia-Ischemia Brain Damage by limma package analysis, five kinds of analyses were performed on them, namely Gene Ontology (GO) and pathway enrichment analysis, protein-protein interaction network, DEG-transcription factor interactions and DEG-microRNA interactions, protein-drug interactions and protein-disease association analysis, and gene-inflammation association analysis and protein-inflammation association analysis.

Results

In total, 12 common DEGs were identified including HSPB1, VIM, MVD, TUBB4A, AACS, ANXA6, DIRAS2, RPH3A, CEND1, KALM, THOP1, AREL1. We also identified 11 hub proteins, three central regulatory transcription factors, and three microRNAs encoded by the DEGs. Protein-drug interaction analysis showed that CYC1 and UQCRFS1 are associated with different drugs. Gene-disease association analysis shows Mammary Neoplasms, Neoplasm Metastasis, Schizophrenia, and Brain Ischemia diseases are the most relevant to the hub proteins we identified. Gene-inflammation association analysis shows that the hub gene AREL1 is related to inflammatory response, while the protein-inflammation association analysis shows that the hub proteins AKT1 and MAPK14 are related to inflammatory response.

Conclusion

This study provides new insights into the shared molecular mechanisms between AD and nHIBD. These common pathways and hub genes could potentially be used to design therapeutic interventions, reducing the likelihood of Alzheimer's disease development in survivors of neonatal Hypoxic-Ischemia brain injury.

Design, synthesis, and in silico studies of new quinazolinones tagged thiophene, thienopyrimidine, and thienopyridine scaffolds as antiproliferative agents with potential p38α MAPK kinase inhibitory effects

The current work focuses on the creation of novel derivatives of the quinazolinone ring system, with various substituted thiophene, thienopyrimidine, and thienopyridine scaffolds 3a,b-11. Employing the standard MTT assay, every target compound's in vitro antiproliferative efficacy was evaluated in comparison with doxorubicin against both normal WI-38 cells and various cancer cell lines. Derivatives 6, 8a, and 8b demonstrated the most potent activity, alongside their safety profiles against WI-38. The in vitro enzyme assay showed that the new analogues had a better ability to inhibit p38α MAPK kinase than SB 202190 (IC50s = 0.18 ± 0.02, 0.23 ± 0.05, 0.31 ± 0.04, and 0.27 ± 0.06 μM, respectively). Additionally, apoptosis tests conducted on MCF-7 cells revealed that 6, 8a, and 8b significantly increased the levels of Bax (by approximately 7.31, 13.8, and 8.86 fold) and caspase 3 (by approximately 3.55, 4.22, and 3.87 fold), respectively, in comparison to the untreated cells. They decreased the amount of Bcl-2 by ∼1.99, 3.69, and 2.66 fold, respectively. The most powerful counterpart, 8a, underwent additional investigation of the cell cycle and apoptosis. It caused necrotic and apoptotic effects in the late stages and stopped the MCF-7 cell cycle at the G2/M phase. Based on the molecular docking study, candidates 6, 8a, and 8b all fit well within p38α MAPK kinase, with energy scores of -10.88, -11.28, and -10.96 kcal mol-1, respectively. Based on the in silico computer examination of physico-chemical and ADMET properties, the latter analogues seem to be promising candidates for further development and optimization in research.

Dual-action kinase inhibitors influence p38α MAP kinase dephosphorylation

Reversible protein phosphorylation directs essential cellular processes including cell division, cell growth, cell death, inflammation, and differentiation. Because protein phosphorylation drives diverse diseases, kinases and phosphatases have been targets for drug discovery, with some achieving remarkable clinical success. Most protein kinases are activated by phosphorylation of their activation loops, which shifts the conformational equilibrium of the kinase toward the active state. To turn off the kinase, protein phosphatases dephosphorylate these sites, but how the conformation of the dynamic activation loop contributes to dephosphorylation was not known. To answer this, we modulated the activation loop conformational equilibrium of human p38α ΜΑP kinase with existing kinase inhibitors that bind and stabilize specific inactive activation loop conformations. From this, we identified three inhibitors that increase the rate of dephosphorylation of the activation loop phospho-threonine by the PPM serine/threonine phosphatase WIP1. Hence, these compounds are "dual-action" inhibitors that simultaneously block the active site and promote p38α dephosphorylation. Our X-ray crystal structures of phosphorylated p38α bound to the dual-action inhibitors reveal a shared flipped conformation of the activation loop with a fully accessible phospho-threonine. In contrast, our X-ray crystal structure of phosphorylated apo human p38α reveals a different activation loop conformation with an inaccessible phospho-threonine, thereby explaining the increased rate of dephosphorylation upon inhibitor binding. These findings reveal a conformational preference of phosphatases for their targets and suggest a unique approach to achieving improved potency and specificity for therapeutic kinase inhibitors.

Advance on the effects of algal carotenoids on inflammatory signaling pathways

The development of inflammation has an indispensable importance in the self-protection of the human body. However, over-inflammation may damage human health, and inflammatory pathways and inflammasomes have a significant impact on the onset of inflammation. Therefore, how to constrain the development of inflammation through inflammatory pathways or inflammasomes becomes a hot research issue. Carotenoids are a natural pigment and an active substance in algae, with anti-inflammatory and antioxidant effects. Many studies have shown that carotenoids have inhibitory effects on the inflammatory pathways and inflammasomes. In this review, we discussed the mechanism of carotenoids targeting those important inflammatory pathways and their effects on common inflammasome NLRP3 and inflammation-related diseases from the perspective of several inflammatory pathways, including p38 MAPK, IL-6/JAK/STAT3, and PI3K, with a focus on the targets and targeting effects of carotenoids on different inflammatory signaling pathways, and at last proposed possible anti-inflammatory targets.

Potential Signal Pathways and Therapeutic Effects of Mesenchymal Stem Cell on Oxidative Stress in Diseases

Oxidative stress is a biological stress response produced by the destruction of redox equilibrium in aerobic metabolism in organisms, which is closely related to the occurrence of many diseases. Mesenchymal stem cells (MSCs) have been found to improve oxidative stress injury in a variety of diseases, including lung injury, liver diseases, atherosclerotic diseases, diabetes and its complications, ischemia-reperfusion injury, inflammatory bowel disease. The antioxidant stress capacity of MSCs may be a breakthrough in the treatment of these diseases. This review found that MSCs have the ability to resist oxidative stress, which may be achieved through MSCs involvement in mediating the Nrf2, MAPK, NF-κB, AMPK, PI3K/AKT and Wnt4/β-catenin signaling pathways.

Lysosomal damage triggers a p38 MAPK-dependent phosphorylation cascade to promote lysophagy via the small heat shock protein HSP27

Maintenance of lysosomal integrity is essential for cell viability. Upon injury, lysosomes may be targeted for degradation via a selective form of autophagy known as lysophagy. The engulfment of a damaged lysosome by an autophagosome is mediated by the recruitment of adaptor proteins, including SQSTM1/p62. p62 promotes lysophagy via the formation of phase-separated condensates in a mechanism that is regulated by the heat shock protein HSP27. Here, we demonstrate a direct interaction between HSP27 and p62. We used structural modeling to predict the binding interface between HSP27 and p62 and identify several disease-associated mutations that map to this interface. We used proteomics to identify post-translational modifications of HSP27 that regulate HSP27 recruitment to stressed lysosomes, finding robust phosphorylation at several serine residues. Next, we characterized the upstream signaling mechanism leading to HSP27 phosphorylation and found that p38 mitogen-activated protein kinase (MAPK) and its effector kinase MAP kinase-activated protein kinase 2 (MK2) are activated upon lysosomal damage by the kinase mTOR and the production of intracellular reactive oxygen species (ROS). Increased ROS activates p38 MAPK, which in turn allows MK2-dependent phosphorylation of HSP27. Depletion of HSP27 or the inhibition of HSP27 phosphorylation alters the dynamics of p62 condensates on stressed lysosomes, significantly inhibiting p62-dependent lysophagy. Thus, we define a novel lysosomal quality control mechanism in which lysosomal injury triggers a p38 MAPK/MK2 signaling cascade promoting p62-dependent lysophagy. Further, this signaling cascade is activated by many cellular stressors, including oxidative and heat stress, suggesting that other forms of selective autophagy may be regulated by p38 MAPK/MK2/HSP27.

ADAR1 expression in different cancer cell lines and its change under heat shock

Adenosine deaminase acting on RNA 1 (ADAR1) plays an essential role in the development of malignancies by modifying the expression of different oncogenes. ADAR1 presents three distinct activities: adenosine-to-inosine RNA editing, modulating IFN pathways, and response to cellular stress factors. Following stressors such as heat shock, ADAR1p110 isoform relocates from the nucleus to the cytoplasm, where it suppresses RNA degradation which leads to the arrest of apoptosis and cell survival. In this study, we assessed the expression of ADAR1 across different cancer cell lines. We revealed that the presence of ADAR1 varies between cells of different origins and that a high transcript level does not reflect protein abundance. Additionally, we subjected cells to a heat shock in order to evaluate how cellular stress factors affect the expression of ADAR1. Our results indicate that ADAR1 transcript and protein levels are relatively stable and do not change under heat shock in examined cell lines. This research lays a groundwork for future directions on ADAR1-related studies suggesting in which types of cancer ADAR1 may be a promising target for novel therapeutic approaches.

Chemerin, TNF - α and the degree of albuminuria in patients with diabetic kidney disease

BACKGROUND

Chronic inflammation has been increasingly recognized as an essential pathogenic mechanism for the development and progression of diabetic kidney disease (DKD). Chemerin is an adipokine which has been suggested to be related to inflammation and has been correlated with the development of diabetic complications. We aimed to explore the potential links between chemerin, TNF - α, as a marker of systemic inflammation, and the level of albuminuria in patients with type 2 diabetes mellitus (T2DM).

METHOD

The study included 84 patients with T2DM and 10 normoalbuminuric non-diabetic controls. Demographic, clinical and laboratory data including chemerin and TNF-α levels were collected.

RESULTS

A total of 84 diabetic patients were enrolled, 32 males (38.1 %), with mean age 57.9 ± 10.7 years. They were divided into 3 groups: A1: 14 with normalbuminuria, A2: 27 with microalbuminuria, and A3: 43 with macroalbuminuria (uACR < 30, 30-300 and > 300 mg/gm respectively). Chemerin and TNF-α levels increased with the progress of albuminuria (control: 21.3 (14.7 -77), A1: 794 (683-925), A2: 1150 (962.9 - 1221.5) and A3: 1466 (1197.5 - 2002.5) ng/ml; p < 0.001) and (control: 77.9 (59 - 96.8), A1: 85.2 (71-116.3), A2: 87.3 (81 - 97.5) and A3: 99 (85.1 - 142.5) pg/ml; p = 0.009) respectively. Among the diabetics, a significant association was evident between serum chemerin and serum TNF-α (r = 0.53; p < 0.001). On linear stepwise regression analysis, chemerin was significantly associated with TNF-α and HbA1c (unstandardized β 10.881 and 272.68 respectively, p < 0.001); and TNF-α was significantly correlated with chemerin, uACR (unstandardized β 0.059 and 0.004 respectively, p < 0.001) and HbA1c (unstandardized β -13.699, p = 0.014).

CONCLUSION

Our findings suggest a potential role of chemerin and TNF-α in the development and progression of DKD, and thus support the role of the inflammatory pathway. Larger follow up studies are warranted to further explore the potential links between chemerin, inflammation and DKD.

Manipulation of signaling pathways in bone tissue engineering and regenerative medicine: Current knowledge, novel strategies, and future directions

During osteogenesis, a large number of bioactive molecules, macromolecules, cells, and cellular signals are activated to induce bone growth and development. The activation of molecular pathways leads to the occurrence of cellular events, ultimately resulting in observable changes. Therefore, in the studies of bone tissue engineering and regenerative medicine, it is essential to target fundamental events to exploit the mechanisms involved in osteogenesis. In this context, signaling pathways are activated during osteogenesis and trigger the activation of numerous other processes involved in osteogenesis. Direct influence of signaling pathways should allow to manipulate the signaling pathways themselves and impact osteogenesis. A combination of sequential cascades takes place to drive the progression of osteogenesis. Also, the occurrence of these processes and, more generally, cellular and molecular processes related to osteogenesis necessitate the presence of transcription factors and their activity. The present review focuses on outlining several signaling pathways and transcription factors influencing the development of osteogenesis, and describes various methods of their manipulation to induce and enhance bone formation.

Stress contingent changes in Hog1 pathway architecture and regulation in Candida albicans

The Hog1 stress-activated protein kinase (SAPK) is a key mediator of stress resistance and virulence in Candida albicans. Hog1 activation via phosphorylation of the canonical TGY motif is mediated by the Pbs2 MAPKK, which itself is activated by the Ssk2 MAPKKK. Although this three-tiered SAPK signalling module is well characterised, it is unclear how Hog1 activation is regulated in response to different stresses. Functioning upstream of the Ssk2 MAPKKK is a two-component related signal transduction system comprising three sensor histidine kinases, a phosphotransfer protein Ypd1, and a response regulator Ssk1. Here, we report that Ssk1 is a master regulator of the Hog1 SAPK that promotes stress resistance and Hog1 phosphorylation in response to diverse stresses, except high osmotic stress. Notably, we find Ssk1 regulates Hog1 in a two-component independent manner by functioning to promote interactions between the Ssk2 and Pbs2 kinases. We propose this function of Ssk1 is important to maintain a basal level of Hog1 phosphorylation which is necessary for oxidative stress, but not osmotic stress, mediated Hog1 activation. We find that osmotic stress triggers robust Pbs2 phosphorylation which drives its dissociation from Ssk2. In contrast, Pbs2 is not robustly phosphorylated following oxidative stress and the Ssk1-mediated Ssk2-Pbs2 interaction remains intact. Instead, oxidative stress-stimulated increases in phosphorylated Hog1 is dependent on the inhibition of protein tyrosine phosphatases that negatively regulate Hog1 coupled with the Ssk1-mediated promotion of basal Hog1 activity. Furthermore, we find that inhibition of protein tyrosine phosphatases is linked to the hydrogen peroxide induced oxidation of these negative regulators in a mechanism that is partly dependent on thioredoxin. Taken together these data reveal stress contingent changes in Hog1 pathway architecture and regulation and uncover a novel mode of action of the Ssk1 response regulator in SAPK regulation.

Exploring the Therapeutic Potential for Breast Cancer of Phytochemicals and Secondary Metabolites in Marjoram, Thyme, and Persimmon

Background/Objectives: Breast cancer is the most common cause of death in women worldwide and the most commonly diagnosed cancer. Although several therapeutic approaches are widely used against breast cancer, their adverse effects often lead to symptoms severely affecting the quality of life. Alternative methods have been explored to reduce these adverse effects, and nutraceuticals have yielded promising results. This review will discuss mechanisms of action and potential applications against breast cancer of some nutraceuticals, specifically marjoram, thyme, and persimmon leaves. Methods: A systematic search was conducted across the public databases of PubMed, PubChem, and Google Scholar, with a specific focus on the plant extracts and phytochemicals of interest, as well as the anticarcinogenic mechanisms. Results: Ethnopharmacological and biochemical evidence support the anticarcinogenic role of marjoram, thyme, and persimmon. Numerous phytochemicals contained in these herbs' extracts, like terpenes and flavonoids, possess remarkable potential to effectively treat breast cancer. Discussion: The phytochemicals contained in the reviewed nutraceuticals target the main cellular pathways involved in cell growth and disrupted in carcinogenesis, such as Nf-κB, MAPK/p38, TNF-α/IL-1β, and PI3K/Akt. The mechanisms of action of these compounds can successfully limit the abnormal growth and proliferation of cancerous breast cells. Conclusions: The potential use of the phytochemicals discussed in this review, either alone or in combination, may offer a valid alternative to chemotherapy against breast cancer with virtually no adverse effects, and further research on these molecules may lead to the identification of additional chemo-preventative and chemotherapeutic candidates.

Inhibition of Cardiac p38 Highlights the Role of the Phosphoproteome in Heart Failure Progression

Heart failure (HF) is a complex condition characterized by the inability of the heart to pump sufficient oxygen to the organs to meet their metabolic needs. Among the altered signal transduction pathways associated with HF pathogenesis, the p38 mitogen-activated protein kinase (p38 MAPK) pathway-activated in response to stress- has attracted considerable attention for its potential role in HF progression and cardiac hypertrophy. However, the exact mechanisms by which p38 MAPK influences HF remain unclear. Addressing knowledge gaps may provide insight on why p38 inhibition has yielded inconsistent outcomes in clinical trials. Here we investigate the effects of p38 MAPK inhibition via SB203580 on cardiac remodeling in a guinea pig model of HF and sudden cardiac death. Using a well-established HF model with ascending aortic constriction and daily isoproterenol (ACi) administration, we assessed proteomic changes across three groups: sham-operated controls, untreated ACi, and ACi treated with SB203580 (ACiSB). Cardiac function was evaluated by M-mode echocardiography, while proteome and phosphoproteome profiles were analyzed using multiplexed tandem mass tag labeling and LC-MS/MS. Our findings demonstrate that chronic SB203580 treatment offers protection against progressive decline in cardiac function in HF. The proteomic data indicate that SB203580-treatment exerts broad protection of the cardiac phosphoproteome, beyond inhibiting maladaptive p38-dependent phosphorylation, extending to PKA and AMPK networks among others, ultimately protecting the phosphorylation status of critical myofibrillar and Ca2+-handling proteins. Though SB203580 had a more restricted impact on widespread protein changes in HF, its biosignature was consistent with preserved mitochondrial energetics as well as reduced oxidative and inflammatory stress.

Antioxidant and Anti-Inflammatory Effects of Opuntia Extracts on a Model of Diet-Induced Steatosis

Oxidative stress and inflammation are widely recognised as factors that can initiate and facilitate the development of MAFLD. The aim of this study is to analyse the effect of low and high doses of Opuntia stricta var. dillenii peel extract (L-OD and H-OD, respectively) and Opuntia ficus-indica var. colorada pulp extract (L-OFI and H-OFI, respectively), which are rich in betalains and phenolic compounds, on oxidative stress, inflammation, DNA damage and apoptosis in rat livers with diet-induced steatosis. Steatotic diet led to increased final body and liver weight, serum transaminases, hepatic TG content, oxidative status and cell death. H-OFI treatment decreased serum AST levels, while L-OFI reduced hepatic TG accumulation. Oxidative stress was partially prevented with H-OD and H-OFI supplementation, and pro-inflammatory cytokines levels were especially improved with H-OFI treatment. Moreover, H-OFI appears to prevent DNA damage markers. Finally, H-OD and L-OFI supplementation down-regulated the apoptotic pathway. In conclusion, both H-OD and H-OFI supplementation were effective in regulating the progression to metabolic steatohepatitis, triggering different mechanisms of action.

STC-1 alleviates airway inflammation by regulating epithelial cell apoptosis through the 5-LO pathway

Airway inflammation plays a key role in the pathogenesis and development of asthma. Stanniocalcin-1 (STC-1) has powerful antioxidant, anti-inflammatory and anti-apoptotic functions but its impact on the airway inflammation in asthma lacks evidence. Here, we investigated the effect and potential mechanism of STC-1 on airway inflammation through asthmatic mice model and lipopolysaccharide (LPS)-treated BEAS-2B cells. The data showed that STC-1 treatment before the challenge exerted protective effect on ovalbumin (OVA)-induced asthmatic mice, i.e., decreased the inflammatory cell infiltration, mucus secretion, cytokine levels, apoptosis levels, and p38 MAPK signaling. Additionally, STC-1 reduced 5-LO expression. Meanwhile, STC-1 decreased p38 MAPK signaling, cytokine production, mucin MUC5AC production, 5-LO expression and nuclear translocation, and LTB4 production in vitro. Ultimately, transforming growth factor β (TGF- β ), as a 5-LO inducer, reversed the anti-inflammatory and anti-apoptotic effects of STC-1 in BEAS-2B cells by up-regulating 5-LO expression. It reveals the potential of STC-1 to act as an additional therapy to mitigate airway inflammation in asthma and inhibit 5-LO expression.

DNA ligase III mediates deoxynivalenol exposure-induced DNA damage in intestinal epithelial cells by regulating oxidative stress and interaction with PCNA

Deoxynivalenol (DON) is a widely distributed mycotoxin that is severely cytotoxic and genotoxic to animals and humans. The gut is the initial site of DON exposure and absorption, which can cause severe intestinal damage. However, the underlying mechanisms and effective therapeutic approaches remain unknown. Here, the study indicated that DON exposure caused significant DNA damage in intestinal porcine epithelial cells (IPEC-J2), enhanced significantly the expression of γ-H2AX and 8-hydroxy-2'-deoxyguanosine, and altered the mRNA expression of key genes in the DNA repair pathway. Among them, ligases3 (LIG3) is the key DNA damage/repair gene and the only ligase responsible for the replication and maintenance of mitochondrial DNA. The expression of LIG3 was significantly decreased after DON exposure and showed a dose-dependent effect, decreased expression of LIG3 exacerbates DON-induced cytotoxicity and genotoxicity, decreased cell viability, induced apoptosis and cell cycle arrest, activation of inflammatory factors and MAPK pathway. Furthermore, LIG3 directly binds and regulates PCNA and play a positive regulatory role in the cellular cytotoxicity and genotoxicity upon DON exposure. Collectively, the findings elucidate the regulatory function of LIG3 in DON-induced DNA damage, providing valuable insights into identifying molecular targets for the comprehensive prevention and control of DON contamination.

Lanostane triterpenoids from Ganoderma calidophilum exhibit potent anti-tumor activity by inhibiting PTP1B

The species Ganoderma calidophilum represents a distinct variety within the genus Ganoderma and used by the indigenous Li ethnic group as a medicinal agent for the prevention and treatment of cancer. However, the precise biological activity and role of G. calidophilum in antitumor treatment remain largely unresolved. Several lanostane triterpenoids have been isolated from G. calidophilum. The enzyme activity analysis revealed that four lanostane triterpenoids exhibited PTP1B inhibition activity, with minimal inhibition towards SHP2, SHP1, PTPN5, PTPRA, STEP and TCPTP. Molecular docking analysis demonstrated that these compounds primarily bind to the substrate recognition and entry regions of PTP1B. Further analysis indicated that among them, ganoderic aldehyde A (GAA) is a selective and non-competitive PTP1B inhibitor. GAA inhibited the proliferation, colony formation and migration of C33A and MDA-MB-231 cells in a dose-dependent manner. GAA has the capacity to induce apoptosis in a cell-type-specific manner, both in a caspase-dependent and -independent manner. PTP1B siRNA significantly reduced the cytotoxic effect of GAA, while overexpression of PTP1B significantly increased cell growth after GAA treatment. These findings confirm that PTP1B is a functional target of GAA. Research into the mechanisms of action of GAA has revealed that it could inhibit the activation of AKT by inhibiting PTP1B, while simultaneously activating p38, which promotes cell death. It is possible to develop specific PTP1B inhibitors based on the lanosterol triterpene skeleton. G. calidophilum has the potential to be developed into functional foods or drugs with the aim of preventing and treating cancer.

Bioactivities of Quinic Acids from Vitex rotundifolia Obtained by Supercritical Fluid Extraction

Acyl-quinic acids (AQAs), present in various plants with many health benefits, are regarded as therapeutic agents in the prevention and treatment of chronic and cardiovascular diseases. The molecular network-guided identification of ten AQA compounds, two new (5 and 7) and eight known compounds, were isolated from V. rotundifolia L. f. by using a newly applied extraction method. Their structures were determined through spectroscopic means, reaction mixtures, and modified Mosher and PGME techniques. These compounds were assessed for their anti-inflammatory and antioxidant capabilities. Notably, compounds 1, 3, 4, 6, 8, and 9 exhibited notable DPPH radical scavenging activity. In LPS-induced HT-29 cells, compounds 2-7 significantly inhibited IL-8 production. Furthermore, compounds 3-5 and 7 markedly suppressed NO production, while compounds 1-10 effectively inhibited IL-6 production in LPS-induced RAW264.7 cells. Western blot analyses revealed that compounds 3-5, and 7 reduced iNOS and COX-2 expression, and compounds 2-5, 7, and 8 also diminished the expression levels of p38 MAPK phosphorylation. Docking studies demonstrated the active compounds' binding affinity with the IL-8, iNOS, COX-2, and p38 MAPK proteins through interactions with essential amino acids within the binding pockets of complexes. The findings suggest that compounds 1, 3, 4, 6, 8, and 9, and compounds 3-5, and 7, hold promise as potential therapeutic agents for treating antioxidative and inflammatory diseases, respectively.

Analysis of the Plasticity of Circulating Tumor Cells Reveals Differentially Regulated Kinases During the Suspension-to-Adherent Transition

BACKGROUND

Research on circulating tumor cells (CTCs) offers the opportunity to better understand the initial steps of blood-borne metastasis as main cause of cancer-related deaths. Here, we have used the colon cancer CTC-MCC-41 and breast cancer CTC-ITB-01 lines, which were both established from human CTCs as permanent cell lines as models to further study CTC biology with special emphasis on anchorage-independent survival and growth.

METHODS AND RESULTS

Both cell lines showed a marked intrinsic plasticity to switch between suspension and adherent in vitro growth, in 2D adherent culture conditions, and established an equilibrium of both growth patterns with predominant adherent cells in the CTC-MCC-41 line (77%) and suspension cells in the CTC-ITB-01 line (85%). Western blot analysis revealed a higher expression of pERK1/2 in CTC-ITB-01 adherent cells compared to the suspension counterpart that suggested the involvement of kinases in this process. Subsequent functional kinome profiling identified several serine/threonine as well as tyrosine kinases that were differentially regulated in adherent and suspension CTCs. In the adherent cells of the breast cancer line CTC-ITB-01 the activity of MSK1, Src family kinases and the PKG family was increased compared to the suspension counterpart. In adherent cells of the colorectal CTC-MCC-41 line, an increased activity of TYRO3 and JAK2 was detected, whereas p38 MAPK was strongly impaired in the suspension CTC-MCC-41 cells. Some of the regulated kinases, which include the Src family, TYRO3, MSK1, JAK2 and p38 MAPK, have been associated with crucial cellular processes including proliferation, migration and dormancy in the past.

CONCLUSIONS

The investigated CTC lines exhibit a high plasticity, similar to the concept of 'adherent-to-suspension transition (AST)' that was recently suggested as a new hallmark of tumor biology by Huh et al. Moreover, we identified differentially regulated kinome profiles that may represent potential targets for future studies on therapeutic interventions.

A leukocyte immune-type receptor specific polyclonal antibody recognizes goldfish kidney leukocytes and activates the MAPK pathway in isolated goldfish kidney neutrophil-like cells

Leukocyte immune-type receptors (LITRs) belong to a large family of teleost immunoregulatory receptors that share phylogenetic and syntenic relationships with mammalian Fc receptor-like molecules (FCRLs). Recently, several putative stimulatory Carassius auratus (Ca)-LITR transcripts, including CaLITR3, have been identified in goldfish. CaLITR3 has four extracellular immunoglobulin-like (Ig-like) domains, a transmembrane domain containing a positively charged histidine residue, and a short cytoplasmic tail region. Additionally, the calitr3 transcript is highly expressed by goldfish primary kidney neutrophils (PKNs) and macrophages (PKMs). To further investigate the immunoregulatory potential of CaLITR3 in goldfish myeloid cells, we developed and characterized a CaLITR3-epitope-specific polyclonal antibody (anti-CaL3.D1 pAb). We show that the anti-CaL3.D1 pAb stains various hematopoietic cell types within the goldfish kidney, as well as in PKNs and PKMs. Moreover, cross-linking of the anti-CaL3.D1-pAb on PKN membranes induces phosphorylation of p38 and ERK1/2, critical components of the MAPK pathway involved in controlling a wide variety of innate immune effector responses such as NETosis, respiratory burst, and cytokine release. These findings support the stimulatory potential of CaLITR3 proteins as activators of fish granulocytes and pave the way for a more in-depth examination of the immunoregulatory functions of CaLITRs in goldfish myeloid cells.