Ser276 phosphorylation of NF-kB p65 by MSK1 controls SCF expression in inflammation

Artificial and Natural Sweeteners Biased T1R2/T1R3 Taste Receptors Transactivate Glycosylated Receptors on Cancer Cells to Induce Epithelial-Mesenchymal Transition of Metastatic Phenotype

Understanding the role of biased taste T1R2/T1R3 G protein-coupled receptors (GPCR) agonists on glycosylated receptor signaling may provide insights into the opposing effects mediated by artificial and natural sweeteners, particularly in cancer and metastasis. Sweetener-taste GPCRs can be activated by several active states involving either biased agonism, functional selectivity, or ligand-directed signaling. However, there are increasing arrays of sweetener ligands with different degrees of allosteric biased modulation that can vary dramatically in binding- and signaling-specific manners. Here, emerging evidence proposes the involvement of taste GPCRs in a biased GPCR signaling crosstalk involving matrix metalloproteinase-9 (MMP-9) and neuraminidase-1 (Neu-1) activating glycosylated receptors by modifying sialic acids. The findings revealed that most natural and artificial sweeteners significantly activate Neu-1 sialidase in a dose-dependent fashion in RAW-Blue and PANC-1 cells. To confirm this biased GPCR signaling crosstalk, BIM-23127 (neuromedin B receptor inhibitor, MMP-9i (specific MMP-9 inhibitor), and oseltamivir phosphate (specific Neu-1 inhibitor) significantly block sweetener agonist-induced Neu-1 sialidase activity. To assess the effect of artificial and natural sweeteners on the key survival pathways critical for pancreatic cancer progression, we analyzed the expression of epithelial-mesenchymal markers, CD24, ADLH-1, E-cadherin, and N-cadherin in PANC-1 cells, and assess the cellular migration invasiveness in a scratch wound closure assay, and the tunneling nanotubes (TNTs) in staging the migratory intercellular communication. The artificial and natural sweeteners induced metastatic phenotype of PANC-1 pancreatic cancer cells to promote migratory intercellular communication and invasion. The sweeteners also induced the downstream NFκB activation using the secretory alkaline phosphatase (SEAP) assay. These findings elucidate a novel taste T1R2/T1R3 GPCR functional selectivity of a signaling platform in which sweeteners activate downstream signaling, contributing to tumorigenesis and metastasis via a proposed NFκB-induced epigenetic reprogramming modeling.

MiR-148a-3p/SIRT7 Axis Relieves Inflammatory-Induced Endothelial Dysfunction

In endothelial cells, miR-148a-3p is involved in several pathological pathways, including chronic inflammatory conditions. However, the molecular mechanism of miR-148a-3p in endothelial inflammatory states is, to date, not fully elucidated. To this end, we investigated the involvement of miR-148a-3p in mitochondrial dysfunction and cell death pathways in human aortic endothelial cells (teloHAECs) treated with interleukin-6 (IL-6), a major driver of vascular dysfunction. The results showed that during IL6-activated inflammatory pathways, including increased protein levels of sirtuin 7 (SIRT7) (p < 0.01), mitochondrial stress (p < 0.001), and apoptosis (p < 0.01), a decreased expression of miR-148a-3p was observed (p < 0.01). The employment of a miR-148a mimic counteracted the IL-6-induced cytokine release (p < 0.01) and apoptotic cell death (p < 0.01), and ameliorated mitochondria redox homeostasis and respiration (p < 0.01). The targeted relationship between miR-148a-3p and SIRT7 was predicted by a bioinformatics database analysis and validated via the dual-luciferase reporter assay. Mechanistically, miR-148a-3p targets the 3' untranslated regions of SIRT7 mRNA, downregulating its expression (p < 0.01). Herein, these in vitro results support the role of the miR-148a-3p/SIRT7 axis in counteracting mitochondrial damage and apoptosis during endothelial inflammation, unveiling a novel target for future strategies to prevent endothelial dysfunction.

Co-Culture of P. gingivalis and F. nucleatum Synergistically Elevates IL-6 Expression via TLR4 Signaling in Oral Keratinocytes

Periodontitis, characterized by persistent inflammation in the periodontium, is intricately connected to systemic diseases, including oral cancer. Bacteria, such as Porphyromonas gingivalis and Fusobacterium nucleatum, play a pivotal role in periodontitis development because they contribute to dysbiosis and tissue destruction. Thus, comprehending the interplay between these bacteria and their impacts on inflammation holds significant relevance in clinical understanding and treatment advancement. In the present work, we explored, for the first time, their impacts on the expressions of pro-inflammatory mediators after infecting oral keratinocytes (OKs) with a co-culture of pre-incubated P. gingivalis and F. nucleatum. Our results show that the co-culture increases IL-1β, IL-8, and TNF-α expressions, synergistically augments IL-6, and translocates NF-kB to the cell nucleus. These changes in pro-inflammatory mediators-associated with chronic inflammation and cancer-correlate with an increase in cell migration following infection with the co-cultured bacteria or P. gingivalis alone. This effect depends on TLR4 because TLR4 knockdown notably impacts IL-6 expression and cell migration. Our study unveils, for the first time, crucial insights into the outcomes of their co-culture on virulence, unraveling the role of bacterial interactions in polymicrobial diseases and potential links to oral cancer.

Functional Selectivity of Cannabinoid Type 1 G Protein-Coupled Receptor Agonists in Transactivating Glycosylated Receptors on Cancer Cells to Induce Epithelial-Mesenchymal Transition Metastatic Phenotype

Understanding the role of biased G protein-coupled receptor (GPCR) agonism in receptor signaling may provide novel insights into the opposing effects mediated by cannabinoids, particularly in cancer and cancer metastasis. GPCRs can have more than one active state, a phenomenon called either 'biased agonism', 'functional selectivity', or 'ligand-directed signaling'. However, there are increasing arrays of cannabinoid allosteric ligands with different degrees of modulation, called 'biased modulation', that can vary dramatically in a probe- and pathway-specific manner, not from simple differences in orthosteric ligand efficacy or stimulus-response coupling. Here, emerging evidence proposes the involvement of CB1 GPCRs in a novel biased GPCR signaling paradigm involving the crosstalk between neuraminidase-1 (Neu-1) and matrix metalloproteinase-9 (MMP-9) in the activation of glycosylated receptors through the modification of the receptor glycosylation state. The study findings highlighted the role of CB1 agonists AM-404, Aravnil, and Olvanil in significantly inducing Neu-1 sialidase activity in a dose-dependent fashion in RAW-Blue, PANC-1, and SW-620 cells. This approach was further substantiated by findings that the neuromedin B receptor inhibitor, BIM-23127, MMP-9 inhibitor, MMP9i, and Neu-1 inhibitor, oseltamivir phosphate, could specifically block CB1 agonist-induced Neu-1 sialidase activity. Additionally, we found that CB1 receptors exist in a multimeric receptor complex with Neu-1 in naïve, unstimulated RAW-Blue, PANC-1, and SW-620 cells. This complex implies a molecular link that regulates the interaction and signaling mechanism among these molecules present on the cell surface. Moreover, the study results demonstrate that CB1 agonists induce NFκB-dependent secretory alkaline phosphatase (SEAP) activity in influencing the expression of epithelial-mesenchymal markers, E-cadherin, and vimentin in SW-620 cells, albeit the impact on E-cadherin expression is less pronounced compared to vimentin. In essence, this innovative research begins to elucidate an entirely new molecular mechanism involving a GPCR signaling paradigm in which cannabinoids, as epigenetic stimuli, may traverse to influence gene expression and contribute to cancer and cancer metastasis.

MAP kinase inhibitor PD98059 regulates Th1, Th9, Th17, and natural T regulatory cells in an experimental autoimmune encephalomyelitis mouse model of multiple sclerosis

Experimental autoimmune encephalitis (EAE), an animal model of multiple sclerosis (MS), provides significant insights into the mechanisms that initiate and drive autoimmunity. MS is a chronic autoimmune disease of the central nervous system, characterized by inflammatory infiltration associated with demyelination. T lymphocyte cells play a crucial role in MS, whereas natural T regulatory (nTreg) cells prevent autoimmune inflammation by suppressing lymphocyte activity. This study sought to investigate the role of PD98059, a selective MAP kinase inhibitor, in Th1, Th9, Th17, and nTreg cells using the SJL/J mouse model of EAE. Following EAE development, the mice were intraperitoneally administered PD98059 (5 mg/kg for two weeks) daily. We evaluated the effects of PD98059 on Th1 (IFN-γ and T-bet), Th9 (IL-9 and IRF4), Th17 (IL-17A and RORγT), and nTreg (FoxP3 and Helios) cells in the spleen using flow cytometry. Moreover, we explored the effects of PD98059 on the IFN-γ, T-bet, IL-9, IRF4, IL-17A, RORγT, FoxP3, and Helios mRNA and protein levels in brain tissues using qRT-PCR and Western blot analyses. PD98059 treatment significantly decreased the proportion of CD4+IFN-γ+, CD4+T-bet+, CD4+IL-9+, CD4+IRF4+, CD4+IL-17A+, CD4+RORγT+, CD4+IL-17A+, and CD4+RORγT+ cells while increasing that of CD4+FoxP3+ and CD4+Helios+ cells. In addition, PD98059 administration decreased the mRNA and protein levels of IFN-γ, T-bet, IL-9, IRF4, IL-17A, and RORγT but increased those of FoxP3 and Helios in the brain tissue of EAE mice. Our findings suggest that PD98059 corrects immune dysfunction in EAE mice, which is concurrent with the modulation of multiple signaling pathways.

8-Oxoguanine DNA glycosylase 1 selectively modulates ROS-responsive NF-κB targets through recruitment of MSK1 and phosphorylation of RelA/p65 at Ser276

Nuclear factor kappa B (NF-κB) activity is regulated by various posttranslational modifications, of which Ser276 phosphorylation of RelA/p65 is particularly impacted by reactive oxygen species (ROS). This modification is responsible for selective upregulation of a subset of NF-κB targets; however, the precise mechanism remains elusive. ROS have the ability to modify cellular molecules including DNA. One of the most common oxidation products is 8-oxo-7,8-dihydroguanine (8-oxoGua), which is repaired by the 8-oxoguanine DNA glycosylase1 (OGG1)-initiated base excision repair pathway. Recently, a new function of OGG1 has been uncovered. OGG1 binds to 8-oxoGua, facilitating the occupancy of NF-κB at promoters and enhancing transcription of pro-inflammatory cytokines and chemokines. In the present study, we demonstrated that an interaction between DNA-bound OGG1 and mitogen-and stress-activated kinase 1 is crucial for RelA/p65 Ser276 phosphorylation. ROS scavenging or OGG1 depletion/inhibition hindered the interaction between mitogen-and stress-activated kinase 1 and RelA/p65, thereby decreasing the level of phospho-Ser276 and leading to significantly lowered expression of ROS-responsive cytokine/chemokine genes, but not that of Nfkbis. Blockade of OGG1 binding to DNA also prevented promoter recruitment of RelA/p65, Pol II, and p-RNAP II in a gene-specific manner. Collectively, the data presented offer new insights into how ROS signaling dictates NF-κB phosphorylation codes and how the promoter-situated substrate-bound OGG1 is exploited by aerobic mammalian cells for timely transcriptional activation of ROS-responsive genes.

Understanding cellular senescence: pathways involved, therapeutics and longevity aiding

A normal somatic cell undergoes cycles of finite cellular divisions. The presence of surveillance checkpoints arrests cell division in response to stress inducers: oxidative stress from excess free radicals, oncogene-induced abnormalities, genotoxic stress, and telomere attrition. When facing such stress when undergoing these damages, there is a brief pause in the cell cycle to enable repair mechanisms. Also, the nature of stress determines whether the cell goes for repair or permanent arrest. As the cells experience transient or permanent stress, they subsequently choose the quiescence or senescence stage, respectively. Quiescence is an essential stage that allows the arrested/damaged cells to go through appropriate repair mechanisms and then revert to the mainstream cell cycle. However, senescent cells are irreversible and accumulate with age, resulting in inflammation and various age-related disorders. In this review, we focus on senescence-associated pathways and therapeutics understanding cellular senescence as a cascade that leads to aging, while discussing the recent details on the molecular pathways involved in regulating senescence and the benefits of therapeutic strategies against accumulated senescent cells and their secretions.

Understanding NK cell biology for harnessing NK cell therapies: targeting cancer and beyond

Gene-engineered immune cell therapies have partially transformed cancer treatment, as exemplified by the use of chimeric antigen receptor (CAR)-T cells in certain hematologic malignancies. However, there are several limitations that need to be addressed to target more cancer types. Natural killer (NK) cells are a type of innate immune cells that represent a unique biology in cancer immune surveillance. In particular, NK cells obtained from heathy donors can serve as a source for genetically engineered immune cell therapies. Therefore, NK-based therapies, including NK cells, CAR-NK cells, and antibodies that induce antibody-dependent cellular cytotoxicity of NK cells, have emerged. With recent advances in genetic engineering and cell biology techniques, NK cell-based therapies have become promising approaches for a wide range of cancers, viral infections, and senescence. This review provides a brief overview of NK cell characteristics and summarizes diseases that could benefit from NK-based therapies. In addition, we discuss recent preclinical and clinical investigations on the use of adoptive NK cell transfer and agents that can modulate NK cell activity.

The clinically relevant CHK1 inhibitor MK-8776 induces the degradation of the oncogenic protein PML-RARα and overcomes ATRA resistance in acute promyelocytic leukemia cells

Acute promyelocytic leukemia (APL) is a hematological disease characterized by the expression of the oncogenic fusion protein PML-RARα. The current treatment approach for APL involves differentiation therapy using all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). However, the development of resistance to therapy, occurrence of differentiation syndrome, and relapses necessitate the exploration of new treatment options that induce differentiation of leukemic blasts with low toxicity. In this study, we investigated the cellular and molecular effects of MK-8776, a specific inhibitor of CHK1, in ATRA-resistant APL cells. Treatment of APL cells with MK-8776 resulted in a decrease in PML-RARα levels, increased expression of CD11b, and increased granulocytic activity consistent with differentiation. Interestingly, we showed that the MK-8776-induced differentiating effect resulted synergic with ATO. We found that the reduction of PML-RARα by MK-8776 was dependent on both proteasome and caspases. Specifically, both caspase-1 and caspase-3 were activated by CHK1 inhibition, with caspase-3 acting upstream of caspase-1. Activation of caspase-3 was necessary to activate caspase-1 and promote PML-RARα degradation. Transcriptomic analysis revealed significant modulation of pathways and upstream regulators involved in the inflammatory response and cell cycle control upon MK-8776 treatment. Overall, the ability of MK-8776 to induce PML-RARα degradation and stimulate differentiation of immature APL cancer cells into more mature forms recapitulates the concept of differentiation therapy. Considering the in vivo tolerability of MK-8776, it will be relevant to evaluate its potential clinical benefit in APL patients resistant to standard ATRA/ATO therapy, as well as in patients with other forms of acute leukemias.

Elevated GRO-α and IL-18 in serum and brain implicate the NLRP3 inflammasome in frontotemporal dementia

Neuroinflammation is a hallmark of frontotemporal dementia (FTD), a heterogeneous group of proteinopathies characterized by the progressive degeneration of the frontal and temporal lobes. It is marked by microglial activation and subsequent cytokine release. Although cytokine levels in FTD brain and CSF have been examined, the number of cytokines measured in each study is limited and knowledge on cytokine concentrations in FTD serum is scarce. Here, we assessed 48 cytokines in FTD serum and brain. The aim was to determine common cytokine dysregulation pathways in serum and brain in FTD. Blood samples and brain tissue samples from the superior frontal cortex (SFC) were collected from individuals diagnosed with behavioral variant FTD (bvFTD) and healthy controls, and 48 cytokines were measured using a multiplex immunological assay. The data were evaluated by principal component factor analysis to determine the contribution from different components of the variance in the cohort. Levels of a number of cytokines were altered in serum and SFC in bvFTD compared to controls, with increases in GRO-α and IL-18 in both serum and SFC. These changes could be associated with NLRP3 inflammasome activation or the NFκB pathway, which activates NLRP3. The results suggest the possible importance of the NLRP3 inflammasome in FTD. An improved understanding of the role of inflammasomes in FTD could provide valuable insights into the pathogenesis, diagnosis and treatment of FTD.

Parsimonious Effect of Pentoxifylline on Angiogenesis: A Novel Pentoxifylline-Biased Adenosine G Protein-Coupled Receptor Signaling Platform

Angiogenesis is the physiological process of developing new blood vessels to facilitate the delivery of oxygen and nutrients to meet the functional demands of growing tissues. It also plays a vital role in the development of neoplastic disorders. Pentoxifylline (PTX) is a vasoactive synthetic methyl xanthine derivative used for decades to manage chronic occlusive vascular disorders. Recently, it has been proposed that PTX might have an inhibitory effect on the angiogenesis process. Here, we reviewed the modulatory effects of PTX on angiogenesis and its potential benefits in the clinical setting. Twenty-two studies met the inclusion and exclusion criteria. While sixteen studies demonstrated that pentoxifylline had an antiangiogenic effect, four suggested it had a proangiogenic effect, and two other studies showed it did not affect angiogenesis. All studies were either in vivo animal studies or in vitro animal and human cell models. Our findings suggest that pentoxifylline may affect the angiogenic process in experimental models. However, there is insufficient evidence to establish its role as an anti-angiogenesis agent in the clinical setting. These gaps in our knowledge regarding how pentoxifylline is implicated in host-biased metabolically taxing angiogenic switch may be via its adenosine A2BAR G protein-coupled receptor (GPCR) mechanism. GPCR receptors reinforce the importance of research to understand the mechanistic action of these drugs on the body as promising metabolic candidates. The specific mechanisms and details of the effects of pentoxifylline on host metabolism and energy homeostasis remain to be elucidated.

Cannabinoids Transmogrify Cancer Metabolic Phenotype via Epigenetic Reprogramming and a Novel CBD Biased G Protein-Coupled Receptor Signaling Platform

The concept of epigenetic reprogramming predicts long-term functional health effects. This reprogramming can be activated by exogenous or endogenous insults, leading to altered healthy and different disease states. The exogenous or endogenous changes that involve developing a roadmap of epigenetic networking, such as drug components on epigenetic imprinting and restoring epigenome patterns laid down during embryonic development, are paramount to establishing youthful cell type and health. This epigenetic landscape is considered one of the hallmarks of cancer. The initiation and progression of cancer are considered to involve epigenetic abnormalities and genetic alterations. Cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer development, including DNA methylation, histone modifications, nucleosome positioning, non-coding RNAs, and microRNA expression. Endocannabinoids are natural lipid molecules whose levels are regulated by specific biosynthetic and degradative enzymes. They bind to and activate two primary cannabinoid receptors, type 1 (CB1) and type 2 (CB2), and together with their metabolizing enzymes, form the endocannabinoid system. This review focuses on the role of cannabinoid receptors CB1 and CB2 signaling in activating numerous receptor tyrosine kinases and Toll-like receptors in the induction of epigenetic landscape alterations in cancer cells, which might transmogrify cancer metabolism and epigenetic reprogramming to a metastatic phenotype. Strategies applied from conception could represent an innovative epigenetic target for preventing and treating human cancer. Here, we describe novel cannabinoid-biased G protein-coupled receptor signaling platforms (GPCR), highlighting putative future perspectives in this field.

Paeoniflorin-6'-O-benzene sulfonate protected the intestinal epithelial barrier by restoring the inhibitory effect of GRK2 and β-arrestin 2 on ERK1/2-NF-κB

Peoniflorin-6'-O-benzene sulfonate (CP-25) inhibited the activity of GRK2 to exert anti-inflammatory and immunomodulatory effects. This study aimed to investigate the effect of CP-25 the intestinal epithelial barrier and the mechanism. CaCO-2 cell monolayer and dextran sulfate salt (DSS)-induced colitis mouse model was used to evaluate intestinal epithelial barrier function in vitro and in vivo, respectively. Results showed that CP-25 prevented dysfunction of the intestinal epithelial barrier and inhibited NF-κB p65 activation in TNF-α-induced CaCO-2 cells. The colon structure destroyed in DSS-induced colitis mice was improved by CP-25. CP-25 has a role in inhibition membrane translocation of GRK2-β-arrestin 2 complex, stabilization of the binding of GRK2 and β-arrestin 2 to ERK1/2 in cytoplasm. Subsequently down-regulated the nuclear transcription and transactivation of NF-κB p65 via inhibiting its phosphorylation of Ser536, and Ser276, respectively and restored the epithelial barrier function. In conclusion, CP-25 inhibited ERK1/2-NF-κB activation and thereby protected the intestinal epithelial barrier, which was associated with restoring the inhibition of GRK2 and β-arrestin 2 on ERK1/2.

Anti-Inflammatory Activity and Mechanism of Sweet Corn Extract on Il-1β-Induced Inflammation in a Human Retinal Pigment Epithelial Cell Line (ARPE-19)

Age-related macular degeneration (AMD) is an eye disease associated with aging. Development of AMD is related to degeneration and dysfunction of the retinal pigment epithelium (RPE) caused by low-grade chronic inflammation in aged RPE cells leading to visual loss and blindness. Sweet corn is a good source of lutein and zeaxanthin, which were reported to exert various biological activities, including anti-inflammatory activity. The present study aims to investigate the anti-inflammatory activity and mechanisms of SCE to inhibit the production of inflammatory biomarkers related to AMD development. Cells were pretreated with SCE for 1 h followed by stimulation with IL-1β for another 24 h. The results demonstrated that SCE attenuated IL-1β-induced production of IL-6, IL-8, and MCP-1 and the expression of ICAM-1 and iNOS in a dose-dependent manner. In addition, SCE suppressed the phosphorylation of ERK1/2, SAPK/JNK, p38, and NF-κB (p65) in IL-1β-stimulated ARPE-19 cells. These results proved that SCE protected ARPE-19 cells from IL-1β-induced inflammation by inhibiting inflammatory markers partly via suppressing the activation of MAPK and NF-κB signaling pathways. Overall, SCE is a potential agent for the prevention of AMD development, which should be further evaluated in animals.

Treponema denticola Induces Interleukin-36γ Expression in Human Oral Gingival Keratinocytes via the Parallel Activation of NF-κB and Mitogen-Activated Protein Kinase Pathways

The oral epithelial barrier acts as both a physical barrier to the abundant oral microbiome and a sentry for the immune system that, in health, constrains the accumulation of the polymicrobial plaque biofilm. The immune homeostasis during gingivitis that is largely protective becomes dysregulated, unproductive, and destructive to gingival tissue as periodontal disease progresses to periodontitis. The progression to periodontitis is associated with the dysbiosis of the oral microbiome, with increasing prevalences and abundances of periodontal pathogens such as Treponema denticola. Despite the association of T. denticola with a chronic inflammatory disease, relatively little is known about gingival epithelial cell responses to T. denticola infection. Here, we characterized the transcriptome of gingival keratinocytes following T. denticola challenge and identified interleukin-36γ (IL-36γ) as the most differentially expressed cytokine. IL-36γ expression is regulated by p65 NF-κB and the activation of both the Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways downstream of Toll-like receptor 2 (TLR2). Finally, we demonstrate for the first time that mitogen- and stress-activated kinase 1 (MSK1) contributes to IL-36γ expression and may link the activation of MAPK and NF-κB signaling. These findings suggest that the interactions of T. denticola with the gingival epithelium lead to elevated IL-36γ expression, which may be a critical inducer and amplifier of gingival inflammation and subsequent alveolar bone loss.

Endogenous Jaagsiekte sheep retrovirus envelope protein promotes sheep trophoblast cell fusion by activating PKA/MEK/ERK1/2 signaling

BACKGROUND

Endogenous Jaagsiekte sheep retrovirus envelope protein (enJSRV-Env) plays an important role in trophoblast cell fusion in sheep. However, the underlying mechanism remains unclear.

METHODS

Primary endometrial luminal epithelial cells (LECs) were isolated from the sheep uterus and cocultured with sheep trophoblast cells (STCs). Giemsa staining was conducted to count multinucleated cells in the coculture system. Gain- and loss-of-function assays were performed to explore the role of enJSRV-Env in trophoblast cell fusion in the coculture system. Co-immunoprecipitation and mass spectrometry were carried out to identify the interacting partner of enJSRV-Env in the cocultures. Western blot analysis were conducted to determine the activation of protein kinase A (PKA)/mitogen-activated extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling.

RESULTS

Primary LECs were identified by the expression of epithelial marker cytokeratin 18. Overexpression of enJSRV-Env promoted the formation of multinucleated cells in the coculture system. enJSRV-Env activated and physically interacted with PKA, along with the activation of MEK/ERK1/2 signaling. PKA inhibition completely reversed enJSRV-Env-induced MEK/ERK1/2 activation, and ERK1/2 inhibition abolished enJSRV-Env-induced formation of multinucleated cells in the coculture system.

CONCLUSION

enJSRV-Env promotes trophoblast cell fusion in the sheep placenta by activating PKA/MEK/ERK1/2 signaling. This finding reveals a novel mechanism underlying the contribution of enJSRV-Env to trophoblast cell fusion during placental morphogenesis.

The utilisation of resolvins in medicine and tissue engineering

Recent advances in the field of regenerative medicine and biomaterial science have highlighted the importance of controlling immune cell phenotypes at the biomaterial interface. These studies have clearly indicated that a rapid resolution of the inflammatory process, mediated by a switch in the macrophage population towards a reparative phenotype, is essential for tissue regeneration to occur. While various biomaterial surfaces have been developed in order to impart immunomodulatory properties to the resulting constructs, an alternative strategy involving the use of reparative biological cues, known as resolvins, is emerging in regenerative medicine. This review reports on the mechanisms via which resolvins participate in the resolution of inflammation and describes their current utilisation in pre-clinical and clinical settings, along with their effectiveness when combined with biomaterial constructs in tissue engineering applications. STATEMENT OF SIGNIFICANCE: The resolution of the inflammatory process is necessary for achieving tissue healing and regeneration. Resolvins are lipid mediators and play a key role in the resolution of the inflammatory response and can be used in as biological cues to promote tissue regeneration. This review describes the various biological inflammatory mechanisms and pathways involving resolvins and how their action results in a pro-healing response. The use of these molecules in the clinical setting is then summarised for various applications along with their limitations. Lastly, the review focuses on the emergence resolvins in tissue engineering products including the use of a more stable form which holds greater prospect for regenerative purposes.

Galectin-8, cytokines, and the storm

Galectin-8 (Gal-8) belongs to a family of animal lectins that modulate cell adhesion, cell proliferation, apoptosis, and immune responses. Recent studies have shown that mammalian Gal-8 induces in an autocrine and paracrine manner, the expression and secretion of cytokines and chemokines such as RANKL, IL-6, IL-1β, SDF-1, and MCP-1. This involves Gal-8 binding to receptor complexes that include MRC2/uPAR/LRP1, integrins, and CD44. Receptors ligation triggers FAK, ERK, Akt, and the JNK signaling pathways, leading to induction of NF-κB that promotes cytokine expression. Indeed, immune-competent Gal-8 knockout (KO) mice express systemic lower levels of cytokines and chemokines while the opposite is true for Gal-8 transgenic animals. Cytokine and chemokine secretion, induced by Gal-8, promotes the migration of cancer cells toward cells expressing this lectin. Accordingly, Gal-8 KO mice experience reduced tumor size and smaller and fewer metastatic lesions when injected with cancer cells. These observations suggest the existence of a ‘vicious cycle’ whereby Gal-8 expression and secretion promotes the secretion of cytokines and chemokines that further promote Gal-8 expression. This ‘vicious cycle’ could enhance the development of a ‘cytokine storm’ which is a key contributor to the poor prognosis of COVID-19 patients.

Exposure of Microglia to Interleukin-4 Represses NF-κB-Dependent Transcription of Toll-Like Receptor-Induced Cytokines

Interleukin (IL)-4 is a cytokine that affects both adaptive and innate immune responses. In the central nervous system, microglia express IL-4 receptors and it has been described that IL-4-exposed microglia acquire anti-inflammatory properties. We here demonstrate that IL-4 exposure induces changes in the cell surface protein expression profile of primary rhesus macaque microglia and enhances their potential to induce proliferation of T cells with a regulatory signature. Moreover, we show that Toll like receptor (TLR)-induced cytokine production is broadly impaired in IL-4-exposed microglia at the transcriptional level. IL-4 type 2 receptor-mediated signaling is shown to be crucial for the inhibition of microglial innate immune responses. TLR-induced nuclear translocalization of NF-κB appeared intact, and we found no evidence for epigenetic modulation of target genes. By contrast, nuclear extracts from IL-4-exposed microglia contained significantly less NF-κB capable of binding to its DNA consensus site. Further identification of the molecular mechanisms that underlie the inhibition of TLR-induced responses in IL-4-exposed microglia may aid the design of strategies that aim to modulate innate immune responses in the brain, for example in gliomas.

Cordycepin induces M1/M2 macrophage polarization to attenuate the liver and lung damage and immunodeficiency in immature mice with sepsis via NF-κB/p65 inhibition

OBJECTIVES

To explore the impacts of cordycepin and underlying mechanism on the sepsis.

METHODS

The sepsis mice model was built and treated with different concentrations of cordycepin. Then the liver and lung injury caused by cecal ligation and puncture (CLP) was assessed using H&E staining and TUNEL assay. The expression of relevant genes was detected using qRT-PCR analysis and ELISA assays. Besides, the macrophage polarization was checked by flow cytometry.

KEY FINDINGS

Cordycepin could significantly improve the liver and lung injury. Moreover, cordycepin increased the distribution of F4/80+ CD206+ M2-like macrophages and F4/80+ iNOS+ M1-like macrophages through down-regulating the expression of relevant genes. More importantly, cordycepin could monitor the protein expression of iNOS, Arg-1, TNF-α, MCP-1, IL-4 and IL-10 in CLP mice. Meanwhile, the elevated level of p65 induced by CLP was also repressed by the increase of the cordycepin. Moreover, cordycepin played a crucial part in CLP mice through modulating the NF-κB/p65 signalling pathway.

CONCLUSIONS

Cordycepin played an important role in mice with sepsis via reducing the M1/M2 macrophage polarization and modulating the NF-κB/p65 signalling pathway.

CLec-TM1-ERK-GSK3β Pathway Regulates Vibrio splendidus-Induced IL-17 Production in Oyster

C-type lectins are a family of pattern recognition receptors that recognize microbial components and subsequently activate the signaling cascade to induce the production of proinflammatory cytokines. In the current study, the homologs of ERK (named as CgERK) and GSK3β (named as CgGSK3β) and a novel C-type lectin with a transmembrane domain (named as CgCLec-TM1) were identified from oyster Crassostrea gigas CgCLec-TM1 was able to bind Escherichia coli and Vibrio splendidus through its carbohydrate recognition domain and then activated CgERK by inducing its phosphorylation. The activated CgERK interacted with CgGSK3β to phosphorylate it at Ser⁹, which eventually induced the expressions of CgIL-17-1 and CgIL-17-5. The interaction between CgERK and CgGSK3β, as well as the phosphorylation of CgGSK3β, could be inhibited by ERK inhibitor (PD98059) to reduce the expressions of CgIL-17-1 and CgIL-17-5. CgGSK3β in oyster was proposed as a new substrate of CgERK. The results defined a CLec-TM1-ERK-GSK3β signaling pathway in oyster, which was activated by V. splendidus and then induced CgIL-17 productions.

Overexpression of the MSK1 Kinase in Patients With Chronic Lung Allograft Dysfunction and Its Confirmed Role in a Murine Model

BACKGROUND

Chronic lung allograft dysfunction (CLAD) and its obstructive form, the obliterative bronchiolitis (OB), are the main long-term complications related to high mortality rate postlung transplantation. CLAD treatment lacks a significant success in survival. Here, we investigated a new strategy through inhibition of the proinflammatory mitogen- and stress-activated kinase 1 (MSK1) kinase.

METHODS

MSK1 expression was assessed in a mouse OB model after heterotopic tracheal allotransplantation. Pharmacological inhibition of MSK1 (H89, fasudil, PHA767491) was evaluated in the murine model and in a translational model using human lung primary fibroblasts in proinflammatory conditions. MSK1 expression was graded over time in biopsies from a cohort of CLAD patients.

RESULTS

MSK1 mRNA progressively increased during OB (6.4-fold at D21 posttransplantation). Inhibition of MSK1 allowed to counteract the damage to the epithelium (56% restoration for H89), and abolished the recruitment of MHCII+ (94%) and T cells (100%) at the early inflammatory phase of OB. In addition, it markedly decreased the late fibroproliferative obstruction in allografts (48%). MSK1 inhibitors decreased production of IL-6 (whose transcription is under the control of MSK1) released from human lung fibroblasts (96%). Finally, we confirmed occurrence of a 2.9-fold increased MSK1 mRNA expression in lung biopsies in patients at 6 months before CLAD diagnosis as compared to recipients with stable lung function.

CONCLUSIONS

These findings suggest the overall interest of the MSK1 kinase either as a marker or as a potential therapeutic target in lung dysfunction posttransplantation.

Flavopiridol (Alvocidib), a Cyclin-dependent Kinases (CDKs) Inhibitor, Found Synergy Effects with Niclosamide in Cutaneous T-cell Lymphoma

Flavopiridol (FVP; Alvocidib), a CDKs inhibitor, is currently undergoing clinical trials for treatment of leukemia and other blood cancers. Our studies demonstrated that FVP also inhibited p38 kinases activities with IC₅₀ (μM) for p38α: 1.34; p38 β: 1.82; p38γ: 0.65, and p38δ: 0.45. FVP showed potent cytotoxicity in cutaneous T-cell lymphoma (CTCL) Hut78 cells, with IC₅₀ <100 nM. NMR analysis revealed that FVP bound to p38γ in the ATP binding pocket, causing allosteric perturbation from sites surrounding the ATP binding pocket. Kinomic profiling with the PamGene platform in both cell-based and cell-free analysis further revealed dosage of FVP significantly affects downstream pathways in treated CTCL cells, which suggested a need for development of synergistic drugs with FVP to prevent its clinically adverse effects. It led us discover niclosamide as a synergistic drug of FVP for our future in vivo study.

MSK1 downregulation is involved in inflammatory responses following subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH) is a life-threatening neurological disease. Recently, inflammatory factors have been confirmed to be responsible for the brain damage associated with SAH. Therefore, studying the post-SAH inflammatory reaction may clarify the mechanism of SAH. Mitogen and stress-activated protein kinase 1 (MSK1) causes the phosphorylation of NF-κB and regulates the activity of pro-inflammatory transcription factors. The present study aimed to identify the potential role of MSK1 in inflammation and brain damage development following SAH. A cisterna magna blood injection model was established in Sprague-Dawley rats. Hematoxylin and eosin staining, reverse transcription-quantitative polymerase chain reaction assays and double immunofluorescence staining were used to analyze the role of MSK1, IL-1β and TNF-α in the inflammatory process after SAH. In a model of lipopolysaccharide-induced astrocyte inflammation, the effect of overexpressing MSK1 overexpression was analyzed by western blot analysis. The results demonstrated that MSK1 expression were negatively correlated with TNF-α and IL-1β expression levels, and reached peak levels 2 days after TNF-α and IL-1β. The double immunofluorescence staining results showed that the expression of MSK1 was in the same plane of view as TNF-α and IL-1β in the brain cortex. Furthermore, the in vitro studies indicated that the overexpression of MSK1 inhibited the expression of TNF-α and IL-1β following LPS challenge. These results imply that MSK1 may be involved in the inflammatory reaction following SAH, and may potentially serve as a negative regulator of inflammation.

Gastric Electrical Pacing Reduces Apoptosis of Interstitial Cells of Cajal via Antioxidative Stress Effect Attributing to Phenotypic Polarization of M2 Macrophages in Diabetic Rats

BACKGROUND

Gastric electrical pacing (GEP) could restore interstitial cells of Cajal in diabetic rats. M2 macrophages contribute to the repair of interstitial cells of Cajal injury though secreting heme oxygenase-1 (HO-1). The aim of the study is to investigate the effects and mechanisms of gastric electrical pacing on M2 macrophages in diabetic models.

METHODS

Sixty male Sprague-Dawley rats were randomized into control, diabetic (DM), diabetic with the sham GEP (DM+SGEP), diabetic with GEP1 (5.5 cpm, 100 ms, 4 mA) (DM+GEP1), diabetic with GEP2 (5.5 cpm, 300 ms, 4 mA) (DM+GEP2), and diabetic with GEP3 (5.5 cpm, 550 ms, 4 mA) (DM+GEP3) groups. The apoptosis of interstitial cells of Cajal and the expression of macrophages were detected by immunofluorescence technique. The expression levels of the Nrf2/HO-1 and NF-κB pathway were evaluated using western blot analysis or immunohistochemical method. Malonaldehyde, superoxide dismutase, and reactive oxygen species were tested to reflect the level of oxidative stress.

RESULTS

Apoptosis of interstitial cells of Cajal was increased in the DM group but significantly decreased in the DM+GEP groups. The total number of macrophages was almost the same in each group. In the DM group, M1 macrophages were increased and M2 macrophages were decreased. However, M2 macrophages were dramatically increased and M1 macrophages were reduced in the DM+GEP groups. Gastric electrical pacing improved the Nrf2/HO-1 pathway and downregulated the phosphorylation of NF-κB. In the DM group, the levels of malonaldehyde and reactive oxygen species were elevated and superoxide dismutase was lowered, while gastric electrical pacing reduced the levels of malonaldehyde and reactive oxygen species and improved superoxide dismutase.

CONCLUSION

Gastric electrical pacing reduces apoptosis of interstitial cells of Cajal though promoting M2 macrophages polarization to play an antioxidative stress effect in diabetic rats, which associates with the activated Nrf2/HO-1 pathway and the phosphorylation of NF-κB pathway.

Design, Synthesis and Biological Evaluation of Arylpyridin-2-yl Guanidine Derivatives and Cyclic Mimetics as Novel MSK1 Inhibitors. An Application in an Asthma Model

Mitogen- and Stress-Activated Kinase 1 (MSK1) is a nuclear kinase, taking part in the activation pathway of the pro-inflammatory transcription factor NF-kB and is demonstrating a therapeutic target potential in inflammatory diseases such as asthma, psoriasis and atherosclerosis. To date, few MSK1 inhibitors were reported. In order to identify new MSK1 inhibitors, a screening of a library of low molecular weight compounds was performed, and the results highlighted the 6-phenylpyridin-2-yl guanidine (compound 1a, IC₅₀~18 µM) as a starting hit for structure-activity relationship study. Derivatives, homologues and rigid mimetics of 1a were designed, and all synthesized compounds were evaluated for their inhibitory activity towards MSK1. Among them, the non-cytotoxic 2-aminobenzimidazole 49d was the most potent at inhibiting significantly: (i) MSK1 activity, (ii) the release of IL-6 in inflammatory conditions in vitro (IC₅₀~2 µM) and (iii) the inflammatory cell recruitment to the airways in a mouse model of asthma.

Baicalin suppresses Propionibacterium acnes-induced skin inflammation by downregulating the NF-κB/MAPK signaling pathway and inhibiting activation of NLRP3 inflammasome

Acne is a kind of common, chronic skin condition caused by the inflammation of the sebaceous glands in hair follicles. Recent studies have demonstrated that baicalin (BA) possesses potential anti-inflammatory properties. In this study, we evaluated the anti-inflammatory activity of BA in vitro and in vivo. Heat-killed Propionibacterium acnes-induced THP-1 cells and live P. acnes-injected male Sprague Dawley rats were used for establishing the acne model. The rate of ear swelling was calculated, and the severity was determined by hematoxylin and eosin staining. The production of cytokines [interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF-α)] in the cell supernatant and ear tissue homogenates was measured by ELISA. Protein levels of JNK, ERK, P38, IκBα, P65, Nod-like receptor pyrin domain-containing 3 (NLRP3), pro-caspase-1, and IL-1β in THP-1 cells and ear tissues were detected by western blotting. NLRP3 and IL-1β were detected by immunohistochemistry, and the NLRP3, IL-1β and pro-caspase-1 mRNAs were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that BA decreased the expression of pro-inflammatory cytokines in vitro and in vivo. Moreover, BA down-regulated the phosphorylation of JNK, ERK1/2, and κBα and inhibited the nuclear translocation of p65. Furthermore, BA inhibited the activation of NLRP3 inflammasome, at both the gene and protein levels. Taken together, the results demonstrated that BA might exert its anti-inflammatory activity by inhibiting NF-κB/MAPK signaling pathways and consequently suppressing the activation of the NLRP3 inflammasome both in vivo and in vitro.

Transcriptomics-Based Characterization of the Toxicity of ZnO Nanoparticles Against Chronic Myeloid Leukemia Cells

INTRODUCTION

Zinc oxide nanoparticles (ZnO NPs) have recently attracted attention as potential anti-cancer agents. To the best of our knowledge, the toxicity of ZnO NPs against human chronic myeloid leukemia cells (K562 cell line) has not been studied using transcriptomics approach.

OBJECTIVE

The goals of this study were to evaluate the capability of ZnO NPs to induce apoptosis in human chronic myeloid leukemia cells (K562 cells) and to investigate the putative mechanisms of action.

METHODS

We used viability assay and flowcytometry coupled with Annexin V-FITC and propidium iodide to investigate the toxicity of ZnO NPs on K562 cells and normal peripheral blood mononuclear cells. Next we utilized a DNA microarray-based transcriptomics approach to characterize the ZnO NPs-induced changes in the transcriptome of K562 cells.

RESULTS

ZnO NPs exerted a selective toxicity (mainly by apoptosis) on the leukemic cells (p≤0.005) and altered their transcriptome; 429 differentially expressed genes (DEGs) with fold change (FC)≥4 and p≤0.008 with corrected p≤0.05 were identified in K562 cells post treatment with ZnO NPs. The over-expressed genes were implicated in "response to zinc", "response to toxic substance" and "negative regulation of growth" (corrected p≤0.05). In contrast, the repressed genes positively regulated "cell proliferation", "cell migration", "cell adhesion", "receptor signaling pathway via JAK-STAT" and "phosphatidylinositol 3-kinase signaling" (corrected p≤0.05). Lowering the FC to ≥1.5 with p≤0.05 and corrected p≤0.1 showed that ZnO NPs over-expressed the anti-oxidant defense system, drove K562 cells to undergo mitochondrial-dependent apoptosis, and targeted NF-κB pathway.

CONCLUSION

Taken together, our findings support the earlier studies that reported anti-cancer activity of ZnO NPs and revealed possible molecular mechanisms employed by ZnO NPs to induce apoptosis in K562 cells.

SARS-CoV-2 multifaceted interaction with the human host. Part II: Innate immunity response, immunopathology, and epigenetics

The SARS-CoV-2 makes its way into the cell via the ACE2 receptor and the proteolytic action of TMPRSS2. In response to the SARS-CoV-2 infection, the innate immune response is the first line of defense, triggering multiple signaling pathways to produce interferons, pro-inflammatory cytokines and chemokines, and initiating the adaptive immune response against the virus. Unsurprisingly, the virus has developed strategies to evade detection, which can result in delayed, excessive activation of the innate immune system. The response elicited by the host depends on multiple factors, including health status, age, and sex. An overactive innate immune response can lead to a cytokine storm, inflammation, and vascular disruption, leading to the vast array of symptoms exhibited by COVID-19 patients. What is known about the expression and epigenetic regulation of the ACE2 gene and the various players in the host response are explored in this review.

Mycosporine-like amino acids stimulate hyaluronan secretion by up-regulating hyaluronan synthase 2 via activation of the p38/MSK1/CREB/c-Fos/AP-1 axis

Hyaluronan (HA) is an extracellular matrix glycosaminoglycan that critically supports the physicochemical and mechanical properties of the skin. Here, we demonstrate that mycosporine-like amino acids (MAAs), which typically function as UV-absorbing compounds, can stimulate HA secretion from normal human fibroblasts. MAA-stimulated HA secretion was associated with significantly increased and decreased levels of mRNAs encoding HA synthase 2 (HAS2) and the HA-binding protein involved in HA depolymerization (designated HYBID), respectively. Using immunoblotting, we found that MAAs at 10 and at 25 μg/ml stimulate the phosphorylation of the mitogen-activated protein kinase (MAPK) p38, extracellular signal-regulated kinase (ERK)/c-Jun, and mitogen- and stress-activated protein kinase 1 (MSK1) (at Thr-581, Ser-360, and Ser-376, respectively) and activation of cAMP-responsive element-binding protein (CREB) and activating transcription factor 2 (ATF2), but not phosphorylation of JUN N-terminal kinase (JNK) or NF-κB (at Ser-276 or Ser-536, respectively), and increased c-Fos protein levels. Moreover, a p38-specific inhibitor, but not inhibitors of MAPK/ERK kinase (MEK), JNK, or NF-κB, significantly abrogated the increased expression of HAS2 mRNA, accompanied by significantly decreased MAA-stimulated HA secretion. These results suggested that the p38-MSK1-CREB-c-Fos-transcription factor AP-1 (AP-1) or the p38-ATF2 signaling cascade is responsible for the MAA-induced stimulation of HAS2 gene expression. Of note, siRNA-mediated ATF2 silencing failed to abrogate MAA-stimulated HAS2 expression, and c-Fos silencing abolished the increased expression of HAS2 mRNA. Our findings suggest that MAAs stimulate HA secretion by up-regulating HAS2 mRNA levels through activation of an intracellular signaling cascade consisting of p38, MSK1, CREB, c-Fos, and AP-1.

Regulation of senescence traits by MAPKs

A phenotype of indefinite growth arrest acquired in response to sublethal damage, cellular senescence affects normal aging and age-related disease. Mitogen-activated protein kinases (MAPKs) are capable of sensing changes in cellular conditions, and in turn elicit adaptive responses including cell senescence. MAPKs modulate the levels and function of many proteins, including proinflammatory factors and factors in the p21/p53 and p16/RB pathways, the main senescence-regulatory axes. Through these actions, MAPKs implement key traits of senescence-growth arrest, cell survival, and the senescence-associated secretory phenotype (SASP). In this review, we summarize and discuss our current knowledge of the impact of MAPKs in senescence. In addition, given that eliminating or suppressing senescent cells can improve health span, we discuss the function and possible exploitation of MAPKs in the elimination (senolysis) or suppression (senostasis) of senescent cells.

Hesperidin methyl chalcone interacts with NFκB Ser276 and inhibits zymosan-induced joint pain and inflammation, and RAW 264.7 macrophage activation

Arthritis can be defined as a painful musculoskeletal disorder that affects the joints. Hesperidin methyl chalcone (HMC) is a flavonoid with analgesic, anti-inflammatory, and antioxidant effects. However, its effects on a specific cell type and in the zymosan-induced inflammation are unknown. We aimed at evaluating the effects of HMC in a zymosan-induced arthritis model. A dose-response curve of HMC (10, 30, or 100 mg/kg) was performed to determine the most effective analgesic dose after intra-articular zymosan stimuli. Knee joint oedema was determined using a calliper. Leukocyte recruitment was performed by cell counting on knee joint wash as well as histopathological analysis. Oxidative stress was measured by colorimetric assays (GSH, FRAP, ABTS and NBT) and RT-qPCR (gp91^phox and HO-1 mRNA expression) performed. In vitro, oxidative stress was assessed by DCFDA assay using RAW 264.7 macrophages. Cytokine production was evaluated in vivo and in vitro by ELISA. In vitro NF-κB activation was analysed by immunofluorescence. We observed HMC reduced mechanical hypersensitivity and knee joint oedema, leukocyte recruitment, and pro-inflammatory cytokine levels. We also observed a reduction in zymosan-induced oxidative stress as per increase in total antioxidant capacity and reduction in gp91^phox and increase in HO-1 mRNA expression. Accordingly, total ROS production and macrophage NFκB activation were diminished. HMC interaction with NFκB p65 at Ser276 was revealed using molecular docking analysis. Thus, data presented in this work suggest the usefulness of HMC as an analgesic and anti-inflammatory in a zymosan-induced arthritis model, possibly by targeting NFκB activation in macrophages.

LETMD1 Regulates Phagocytosis and Inflammatory Responses to Lipopolysaccharide via Reactive Oxygen Species Generation and NF-κB Activation in Macrophages

LETM1 domain-containing protein 1 (LETMD1), also known as HCCR-1, is a mitochondrial protein and is known to regulate p53 and STAT3 activities in cancer cells. In this study, we present, for the first time (to our knowledge), data indicating that LETMD1 suppresses multiple immune responses in monocyte/macrophage lineage cells and mouse primary macrophages. Attenuation of LETMD1 expression with specific small interfering RNA and short hairpin RNA constructs enhanced LPS-induced expressions of inflammatory mediators in macrophages. In addition, LETMD1 attenuation caused potentiation of phagocytosis as well as migration in a macrophage-like cell line, U937. These enhancing effects were associated with altered activation of signaling adaptors (such as NF-κB, MAPKs, p53, and JAK-STAT) involved in TLR4 signaling. Especially, LETMD1 selectively regulated TLR4-induced NF-κB activation via MyD88 but not via TIR-domain-containing adapter-inducing IFN-β (TRIF). Attenuation of LETMD1 expression caused mitochondrial hyperpolarization and subsequent decrease in ATP production and increase in mitochondrial/cellular reactive oxygen species (ROS) and intracellular calcium levels. LETMD1 attenuation also enhanced LPS-induced expression of NADPH oxidase (NOX) 2, the main producer of cellular ROS in phagocytes, through augmenting IFN regulatory factor 1. Accordingly, treatment with ROS scavenger, NOX2 suppressing agents, or calcium chelators resulted in suppression of LPS-induced cytokine production as well as NF-κB activation in cells with LETMD1 attenuation. These findings reveal a previously unknown function of LETMD1 and provide evidences showing LETMD1 negatively regulates macrophage functions by modulating mitochondrial function, subsequent ROS generation, and NF-κB activation.

Heracleum moellendorffii roots inhibit the production of pro-inflammatory mediators through the inhibition of NF-κB and MAPK signaling, and activation of ROS/Nrf2/HO-1 signaling in LPS-stimulated RAW264.7 cells

BACKGROUND

Heracleum moellendorffii roots (HM-R) have been long treated for inflammatory diseases such as arthritis, backache and fever. However, an anti-inflammatory effect and the specific mechanism of HM-R were not yet clear. In this study, we for the first time explored the anti-inflammatory of HM-R.

METHODS

The cytotoxicity of HM-R against RAW264.7 cells was evaluated using MTT assay. The inhibition of NO and PGE₂ production by HM-R was evaluated using Griess reagent and Prostaglandin E₂ ELISA Kit, respectively. The changes in mRNA or protein level following HM-R treatment were assessed by RT-PCR and Western blot analysis, respectively.

RESULTS

HM-R dose-dependently blocked LPS-induced NO and PGE₂ production. In addition, HM-R inhibited LPS-induced overexpression of iNOS, COX-2, IL-1β and IL-6 in RAW264.7 cells. HM-R inhibited LPS-induced NF-κB signaling activation through blocking IκB-α degradation and p65 nuclear accumulation. Furthermore, HM-R inhibited MAPK signaling activation by attenuating the phosphorylation of ERK1/2, p38 and JNK. HM-R increased nuclear accumulation of Nrf2 and HO-1 expression. However, NAC reduced the increased nuclear accumulation of Nrf2 and HO-1 expression by HM-R. In HPLC analysis, falcarinol was detected from HM-R as an anti-inflammatory compound.

CONCLUSIONS

These results indicate that HM-R may exert anti-inflammatory activity by inhibiting NF-κB and MAPK signaling, and activating ROS/Nrf2/HO-1 signaling. These findings suggest that HM-R has a potential as a natural material for the development of anti-inflammatory drugs.

Genome reading by the NF-κB transcription factors

The NF-κB family of dimeric transcription factors regulates transcription by selectively binding to DNA response elements present within promoters or enhancers of target genes. The DNA response elements, collectively known as κB sites or κB DNA, share the consensus 5'-GGGRNNNYCC-3' (where R, Y and N are purine, pyrimidine and any nucleotide base, respectively). In addition, several DNA sequences that deviate significantly from the consensus have been shown to accommodate binding by NF-κB dimers. X-ray crystal structures of NF-κB in complex with diverse κB DNA have helped elucidate the chemical principles that underlie target selection in vitro. However, NF-κB dimers encounter additional impediments to selective DNA binding in vivo. Work carried out during the past decades has identified some of the barriers to sequence selective DNA target binding within the context of chromatin and suggests possible mechanisms by which NF-κB might overcome these obstacles. In this review, we first highlight structural features of NF-κB:DNA complexes and how distinctive features of NF-κB proteins and DNA sequences contribute to specific complex formation. We then discuss how native NF-κB dimers identify DNA binding targets in the nucleus with support from additional factors and how post-translational modifications enable NF-κB to selectively bind κB sites in vivo.

Cannabidiol and Cannabinoid Compounds as Potential Strategies for Treating Parkinson's Disease and L-DOPA-Induced Dyskinesia

Parkinson's disease (PD) and L-DOPA-induced dyskinesia (LID) are motor disorders with significant impact on the patient's quality of life. Unfortunately, pharmacological treatments that improve these disorders without causing severe side effects are not yet available. Delay in initiating L-DOPA is no longer recommended as LID development is a function of disease duration rather than cumulative L-DOPA exposure. Manipulation of the endocannabinoid system could be a promising therapy to control PD and LID symptoms. In this way, phytocannabinoids and synthetic cannabinoids, such as cannabidiol (CBD), the principal non-psychotomimetic constituent of the Cannabis sativa plant, have received considerable attention in the last decade. In this review, we present clinical and preclinical evidence suggesting CBD and other cannabinoids have therapeutic effects in PD and LID. Here, we discuss CBD pharmacology, as well as its neuroprotective effects and those of other cannabinoids. Finally, we discuss the modulation of several pro- or anti-inflammatory factors as possible mechanisms responsible for the therapeutic/neuroprotective potential of Cannabis-derived/cannabinoid synthetic compounds in motor disorders.

Resistance to lysosomotropic drugs used to treat kidney and breast cancers involves autophagy and inflammation and converges in inducing CXCL5

Lysosomotropic agents such as sunitinib, lapatinib, and chloroquine belong to a drug family that is being used more frequently to treat advanced cancers. Sunitinib is standard care for metastatic renal cell carcinomas (mRCC) and lapatinib is used for trastuzumab/pertuzumab-refractory cancers. However, patients ineluctably relapse with a delay varying from a few months to a few years. To improve reactivity prior to relapse it is essential to identify the mechanisms leading to such variability. We showed previously that sunitinib became sequestered in lysosomes because of its basic pKa.

Methods: Modifications to gene expression in response to sunitinib and in sunitinib resistant cells were analyzed by transcriptomic and proteomic analysis. ROS production was evaluated by FACS. Nuclear Factor kappa B (NFkB)-dependent transcriptional regulation of inflammatory gene expression was evaluated with a reporter gene. Correlation of CXCL5 with survival was analyzed with an online available data base (TCGA) and using a cohort of patients enrolled in the SUVEGIL clinical trial (NCT00943839).

Results: We now show that sunitinib sequestration in lysosomes induced an incomplete autophagic process leading to activation of the NFkB inflammatory pathway. We defined a subset of inflammatory cytokines that were up-regulated by the drug either after an acute or chronic stimulus. One of the most up-regulated genes in sunitinib-resistant cells was the CXCL5 cytokine. CXCL5 was also induced in RCC by chloroquine and in a model of HER2 positive breast cancer cell lines after acute or chronic treatment with lapatinib. CXCL5 correlated to shorter survival in RCC and to the most aggressive forms of breast cancers. The levels of CXCL5 present in the plasma of patients treated with sunitinib were predictive of the efficacy of sunitinib but not of the VEGF-directed antibody bevacizumab.

Conclusion: This translational study identified CXCL5 as a biomarker of efficacy of lysosomotropic drugs, a potential asset for personalized medicine.

NF-κB p65 and p105 implicate in interleukin 1β-mediated COX-2 expression in melanoma cells

Inflammatory and microenvironmental factors produced by cancer cells are thought to directly or indirectly promote cancer cell growth. Prostaglandins, including prostaglandin E2, have key roles as a microenvironment factor in influencing the development of tumors, and are produced by the rate limiting enzyme cyclooxygenase 2 (COX-2). In this study, we used canine melanoma cells treated with the proinflammatory cytokine interleukin 1β (IL-1β) and investigated the transcriptional factor nuclear factor-κB (NF-κB) signaling in IL-1β-induced COX-2 expression. IL-1β induced prostaglandin E2 release and COX-2 mRNA expression in a time- and dose-dependent manner. In the cells treated with the NF-κB inhibitors BAY11-7082 and TPC-1, IL-1β-mediated prostaglandin E2 release and COX-2 mRNA expression were inhibited. IL-1β also provoked phosphorylation of p65/RelA and p105/NF-κB1, which are members of the NF-κB families. The IL-1β-induced phosphorylation of p65 and p105 was attenuated in the presence of both NF-κB inhibitors. In melanoma cells transfected with siRNA of p65 or p105, IL-1β-mediated COX-2 mRNA expression was inhibited. These findings suggest that canonical activation of NF-κB signaling plays a crucial role for inflammatory states in melanoma cells.

Immune response in the relapsing-remitting experimental autoimmune encephalomyelitis in mice: The role of the NF-κB signaling pathway

Characteristics of the mouse model of relapsing-remitting experimental autoimmune encephalomyelitis (rEAE) closely resemble manifestations of multiple sclerosis in humans. In the present study, we investigated the mechanisms of inflammatory response, focusing on NF-κB pathway activation. Cytokine response in rEAE mice was multiphasic: the early phase was characterized by the increase in interferon-γ level in plasma. In the later stage, the level of interleukin-17, but not of interferon-γ, was increased. The early phase of rEAE was also accompanied by increased RelA/p65 phosphorylation at Ser276 in spleen cells, whereas the rEAE maintenance phase was characterized by RelA/p65 phosphorylation at Ser536 and IKK phosphorylation. The IKKα/β inhibitor reduced interleukin-17 and interferon-γ levels in plasma and alleviated rEAE symptoms. The IKKα/β inhibitor decreased IKK and p65(Ser536) phosphorylation, but doubled p65(Ser276) phosphorylation in rEAE mice. The increased RelA/p65(Ser276) phosphorylation coincided in time with the production of interferon-γ, Hsp72, and the early phase of IL-17 generation, whereas increased RelA/p65(Ser536) phosphorylation coincided with the activation of IKK, SAPK/JNK, and p53, as well as the late phase of IL-17 production, indicating the role of the RelA/p65 phosphorylation events in the induction and maintenance of rEAE.

Intracellular Signaling Mechanisms Involved in the Biological Effects of the Xanthophyll Carotenoid Astaxanthin to Prevent the Photo-aging of the Skin in a Reactive Oxygen Species Depletion-independent Manner: The Key Role of Mitogen and Stress-activated Protein Kinase 1

In the first review, we summarized the biological effects of the xanthophyll carotenoid astaxanthin (AX) to prevent UV-induced cutaneous inflammation, abnormal keratinization, pigmentation, and wrinkling in a manner independent of the depletion of reactive oxygen species. In this manuscript, we review what is known about the intracellular signaling mechanisms that are involved in those effects in keratinocytes and in melanocytes. Our research has characterized the intracellular stress signaling mechanism(s) that are involved in the up-regulated expression of genes encoding cyclooxygenase (COX2), interleukin (IL)-8, granulocyte macrophage colony stimulatory factor (GM-CSF), and transglutaminase (TGase)1 in UVB-exposed keratinocytes as well as in the stimulated transcription and/or translation of melanogenic factors, including microphthalmia-associated transcription factor (MITF), in stem cell factor (SCF)-treated melanocytes. The results reveal that while the expression of COX2, IL-8, GM-CSF, and TGase1 stimulated by UVB is due to effects primarily via the NFκB pathway, that stimulation can be abrogated by specifically interrupting the p38/MSK1/NFκBp65Ser276 axis. Further, the stimulation of melanogenesis by SCF can be inhibited by disrupting the phosphorylation of MSK1 via the p38, MSK1, CREB, and MITF axis. The sum of these findings provides new evidence for the interruption of ROS depletion independent-signaling by antioxidants.

Mechanisms of NF-κB p65 and strategies for therapeutic manipulation

The transcription factor NF-κB is a critical regulator of immune and inflammatory responses. In mammals, the NF-κB/Rel family comprises five members: p50, p52, p65 (Rel-A), c-Rel, and Rel-B proteins, which form homo- or heterodimers and remain as an inactive complex with the inhibitory molecules called IκB proteins in resting cells. Two distinct NF-κB signaling pathways have been described: 1) the canonical pathway primarily activated by pathogens and inflammatory mediators, and 2) the noncanonical pathway mostly activated by developmental cues. The most abundant form of NF-κB activated by pathologic stimuli via the canonical pathway is the p65:p50 heterodimer. Disproportionate increase in activated p65 and subsequent transactivation of effector molecules is integral to the pathogenesis of many chronic diseases such as the rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and even neurodegenerative pathologies. Hence, the NF-κB p65 signaling pathway has been a pivotal point for intense drug discovery and development. This review begins with an overview of p65-mediated signaling followed by discussion of strategies that directly target NF-κB p65 in the context of chronic inflammation.

Anti-inflammatory effects of Chinese propolis in lipopolysaccharide-stimulated human umbilical vein endothelial cells by suppressing autophagy and MAPK/NF-κB signaling pathway

This study aimed to investigate the possible benefits of Chinese poplar propolis (CP) in inhibiting inflammation using vascular endothelial cells (VECs) cultured in a nutrient-rich condition exposed to lipopolysaccharide (LPS). Cell proliferation was detected by sulforhodamine B assay and EdU kit. The production of reactive oxygen species (ROS) and level of mitochondrial membrane potential were determined with fluorescent probe DCHF and JC-1, respectively. Protein expression was examined by immunofluorescence staining and western blotting. The results showed that CP (6.25, 12.5, and 25 μg/mL) significantly reduced LPS-induced cytotoxicity, and when challenged with CP substantially suppressed ROS overproduction and protected mitochondrial membrane potential. CP treatment significantly inhibited autophagy by inhibiting LC3B distribution and accumulation, and elevating the p62 level in an mTOR-independent manner but mainly by suppressing the translocation of p53 from the cytoplasm to the nucleus. Furthermore, CP treatment markedly reduced protein levels of TLR4 at 12 and 24 h and significantly suppressed nuclear translocation of NF-κB p65 from cytoplasm to nucleus. In addition, CP treatment significantly reduced the phosphorylation of JNK, ERK1/2, and p38 MAPK. Our findings demonstrated that CP protects VECs from LPS-induced oxidative stress and inflammation, which might be associated with depressing autophagy and MAPK/NF-κB signaling pathway. The results provided novel insights for the potential use of nutrient-rich propolis against inflammation.

Dendritic Cells Actively Limit Interleukin-10 Production Under Inflammatory Conditions via DC-SCRIPT and Dual-Specificity Phosphatase 4

Dendritic cell (DC)-based immunotherapy makes use of the DC’s ability to direct the adaptive immune response toward activation or inhibition. DCs perform this immune orchestration in part by secretion of selected cytokines. The most potent anti-inflammatory cytokine interleukin-10 (IL-10) is under tight regulation, as it needs to be predominantly expressed during the resolution phase of the immune response. Currently it is not clear whether there is active suppression of IL-10 by DCs at the initial pro-inflammatory stage of the immune response. Previously, knockdown of the DC-specific transcription factor DC-SCRIPT has been demonstrated to mediate an extensive increase in IL-10 production upon encounter with pro-inflammatory immune stimuli. Here, we explored how DC-SCRIPT contributes to IL-10 suppression under pro-inflammatory conditions by applying chromatin immunoprecipitation sequencing analysis of DC-SCRIPT and the epigenetic marks H3K4me3 and H3K27ac in human DCs. The data showed binding of DC-SCRIPT to a GA-rich motif at H3K27ac-marked genomic enhancers that associated with genes encoding MAPK dual-specificity phosphatases (DUSPs). Functional studies revealed that upon knockdown of DC-SCRIPT, human DCs express much less DUSP4 and exhibit increased phosphorylation of the three major MAPKs (ERK, JNK, and p38). Enhanced ERK signaling in DC-SCRIPT-knockdown-DCs led to higher production of IL-10, which was reverted by rescuing DUSP4 expression. Finally, DC-SCRIPT-knockdown-DCs induced less IFN-γ and increased IL-10 production in naïve T cells, indicative for a more anti-inflammatory phenotype. In conclusion, we have delineated a new mechanism by which DC-SCRIPT allows DCs to limit IL-10 production under inflammatory conditions and potentiate pro-inflammatory Th1 responses. These insights may be exploited to improve DC-based immunotherapies.

Exclusive enteral nutrition protects against inflammatory bowel disease by inhibiting NF‑κB activation through regulation of the p38/MSK1 pathway

Although enteral nutrition therapy for inflammatory bowel disease has been confirmed to be an effective treatment method, the exact mechanism responsible for the effects of enteral nutrition remains unclear. The aim of the present study was to investigate the protective effect of exclusive enteral nutrition (EEN) against colitis, and to elucidate the potential mechanisms by inhibiting p65 activation via regulating the p38/mitogen‑ and stress‑activated protein kinase‑1 (MSK1) pathway. Experiments were performed by establishing dextran sulfate sodium (DSS)‑mice colitis and picrylsulfonic acid solution (TNBS)‑induced rat colitis, and the results demonstrated that EEN treatment attenuated body weight loss, colon length shortening and colonic pathological damage caused by colitis. EEN also inhibited inflammatory cells infiltration and decreased myeloperoxidase and inducible nitric oxide synthase activities. Furthermore, EEN significantly reduced the production of pro‑inflammatory mediators in serum and the colon. Mechanically, EEN suppressed activation of p65 by inhibiting the p38/MSK1 pathway. In conclusion, the present study demonstrated that EEN attenuated DSS‑ and TNBS‑induced colitis by inhibiting p65 activation via regulating the p38/MSK1 pathway, thus suggesting that EEN is effective in the treatment of colitis.