β-Asarone suppresses TNF-α expression through DNA methylation and c-Jun-mediated transcription modulation in scratch-injured neuronal cells

Management of the Brain: Essential Oils as Promising Neuroinflammation Modulator in Neurodegenerative Diseases

Neuroinflammation, a pivotal factor in the pathogenesis of various brain disorders, including neurodegenerative diseases, has become a focal point for therapeutic exploration. This review highlights neuroinflammatory mechanisms that hallmark neurodegenerative diseases and the potential benefits of essential oils in counteracting neuroinflammation and oxidative stress, thereby offering a novel strategy for managing and mitigating the impact of various brain disorders. Essential oils, derived from aromatic plants, have emerged as versatile compounds with a myriad of health benefits. Essential oils exhibit robust antioxidant activity, serving as scavengers of free radicals and contributing to cellular defense against oxidative stress. Furthermore, essential oils showcase anti-inflammatory properties, modulating immune responses and mitigating inflammatory processes implicated in various chronic diseases. The intricate mechanisms by which essential oils and phytomolecules exert their anti-inflammatory and antioxidant effects were explored, shedding light on their multifaceted properties. Notably, we discussed their ability to modulate diverse pathways crucial in maintaining oxidative homeostasis and suppressing inflammatory responses, and their capacity to rescue cognitive deficits observed in preclinical models of neurotoxicity and neurodegenerative diseases.

UHRF1-induced connexin26 methylation is involved in hearing damage triggered by intermittent hypoxia in neonatal rats

Ubiquitin-like with plant homeodomain and ring finger domains 1 (UHRF1) promotes the maintenance of established patterns of DNA methylation in mammalian cells. Extensive methylation of connexin26 (COX26) during hearing impairment has been demonstrated. The present study aims to determine whether UHRF1 can induce the methylation of COX26 in cochlea damaged by intermittent hypoxia (IH). After the establishment of the cochlear injury model through IH treatment or isolation of the cochlea containing Corti's organ, pathological changes were observed via HE staining. Expressions of COX26 and UHRF1 were detected by quantitative reverse-transcription polymerase chain reaction and Western blot. The effect of COX26 methylation levels was analyzed by methylation-specific PCR (MSP). Phalloidin/immunofluorescence staining was used to observe structural changes. The binding relationship between UHRF1 and COX26 was verified by chromatin immunoprecipitation. IH caused cochlear damage, accompanied by increased methylation of COX26 and expression of UHRF1 in the cochlea of neonatal rats. CoCl₂ treatment caused the loss of cochlear hair cells, downregulation and hypermethylation of COX26, abnormal upregulation of UHRF1, and disordered expressions of apoptosis-related proteins. UHRF1 in cochlear hair cells binds to COX26, and its knockdown upregulated COX26 level. Overexpressed COX26 partially alleviated the CoCl₂-caused cell damage. UHRF1 induces COX26 methylation and aggravates the cochlear damage caused by IH.

LncRNA HOTAIRM1 Involved in Nano NiO-Induced Pulmonary Fibrosis via Regulating PRKCB DNA Methylation-Mediated JNK/c-Jun Pathway

Nickel oxide nanoparticles (Nano NiO) lead to pulmonary fibrosis, and the mechanisms are associated with epigenetics. This study aimed to clarify the regulatory relationship among long noncoding RNA HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1), DNA methylation and expression of protein kinase C beta (PRKCB), and JNK/c-Jun pathway in Nano NiO-induced pulmonary fibrosis. Therefore, we constructed the rat pulmonary fibrosis model by intratracheal instillation of Nano NiO twice a week for 9 weeks and established the collagen deposition model by treating BEAS-2B cells with Nano NiO for 24 h. Here, the DNA methylation pattern was analyzed by whole-genome bisulfite sequencing in rat fibrotic lung tissues. Then, we integrated mRNA transcriptome data and found 93 DNA methylation genes with transcriptional significance. Meanwhile, the data showed that Nano NiO caused the down-regulation of lncRNA HOTAIRM1, the hypomethylation, and up-regulation of PRKCB2, JNK/c-Jun pathway activation, and collagen deposition (the up-regulated Col-I and α-SMA) both in vivo and in vitro. DNMTs inhibitor 5-AZDC attenuated Nano NiO-induced PRKCB2 expression, JNK/c-Jun pathway activation, and collagen deposition, but overexpression of PRKCB2 aggravated the changes mentioned indicators in Nano NiO-induced BEAS-2B cells. Furthermore, JNK/c-Jun pathway inhibitor (SP600125) alleviated Nano NiO-induced excessive collagen formation. Additionally, overexpression of HOTAIRM1 restrained the PRKCB hypomethylation, the activation of JNK/c-Jun pathway, and collagen formation induced by Nano NiO in BEAS-2B cells. In conclusion, these findings demonstrated that HOTAIRM1 could arrest Nano NiO-induced pulmonary fibrosis by suppressing the PRKCB DNA methylation-mediated JNK/c-Jun pathway.

Inflammatory factor tumor necrosis factor-α (TNF-α) activates P-glycoprotein (P-gp) by phosphorylating c-Jun and thus promotes transportation in placental cells

BACKGROUND

P-glycoprotein (P-gp), encoded by the ABCB1 gene, actively pumps drugs and other xenobiotics from trophoblast cells back into the maternal circulation and thus acts as one of the most critical protectors of the fetus. The effect of tumor necrosis factor-α (TNF-α) on P-gp and molecule-transporting activity remains unknown. The goal of this study was to investigate the role of TNF-α in placental molecule-transporting activity and the underlies mechanisms.

METHODS

Cultured human placental choriocarcinoma cell lines, Bewo, JEG-3 and JAR, were used in this study. Cultured cells were incubated with 5, 10 and 20 ng/mL of recombinant TNF-α (rTNF-α) for 24 h, respectively, for follow-up experiments. The dimer form and expression of activator protein-1 (AP-1) family members were detected using Western blot (WB) and chromatin immunoprecipitation (ChIP). mRNA and protein expression of ABCB1 were detected using reverse transcriptional quantitative polymerase chain reaction (RT-qPCR) and WB, respectively. Double luciferase labeling was used to verify the concentration of digoxin. Electromobility shift assay (EMSA) and ChIP were used to identify the binding ability of c-Jun to ABCB1 gene promoter. Proliferation and apoptosis of Bewo cells were determined using flow cytometry. Digoxin concentration were determined using dual luciferase labeling method.

RESULTS

Administration of rTNF-α upregulated the expression of c-Jun but not JunB or JunD in a dose-dependent manner and promoted the binding of c-Jun to the ABCB1 promoter region in Bewo cells. rTNF-α also increased the uptake of two P-gp-specific substrates, Rh123 and DiOC₂(3), a function reversed by the addition of SP600125 and SR11302. We also found that rTNF-α increased the efflux ratio of digoxin, an outcome that was reversed, as expected, by inhibiting c-Jun and P-gp binding activities. Furthermore, we identified that rTNF-α tightly regulates the molecule-transporting activity of P-gp by promoting the phosphorylation of c-Jun.

CONCLUSIONS

TNF-α activates P-gp to promote placental molecule-transporting activity by directly upregulating c-Jun expression and phosphorylation. These findings demonstrate the clinical significance of TNF-α in modulating the placental barrier, which plays an important role in protecting fetus against harmful drugs.

Protective effect of α-asarone and β-asarone on Aβ -induced inflammatory response in PC12 cells and its

To investigate effects of α-asarone and β-asarone on induced PC12 cell injury and related mechanisms. Aβ toxic injury cell model was induced by Aβ in PC12 cells. PC12 cells were divided into blank control group, model control group, α-asarone group (0.5, 1.0, β-asarone group (6.3, 12.5, vasoactive intestinal peptide (VIP) group, and VIP antagonist control group. Cell survival rate was detected by CCK-8 kit; cell apoptosis rate was detected by flow cytometry. The levels of inflammatory cytokines interleukin (IL)-1, , tumor necrosis factor (TNF)-α, oxidation-related inducible nitric oxide synthase (iNOS), nitric oxide (NO), apoptosis factors caspase-3 and p53 were detected by ELISA method. The expressions of C-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK) were detected by Western blotting. Compared with model control group, cell survival rates of group, β-asarone group and VIP group increased; the cell apoptosis rate decreased; levels of apoptosis-related factors caspase-3, p53, inflammatory factors IL-1, TNF-α decreased; IL-10 level increased; levels of oxidization-related factors iNOS and NO decreased; the expression of JNK and p38MAPK protein decreased (all <0.05). After VIP antagonist intervention, the survival rate of β-asarone group decreased; apoptosis rate increased; apoptosis related factors caspase-3, p53, inflammatory factors IL-1, TNF-α increased; IL-10 decreased; oxidation related factors iNOS and NO increased; the expression of JNK and p38MAPK protein increased (all <0.05); while there were no significant changes in these indicators of α-asarone group (all >0.05). α-asarone and β-asarone have protective effects on PC12 cell injury induced by Aβ. β-asarone may inhibit inflammatory factors and oxidation-related factors through promoting VIP secretion, regulating JNK/MAPK pathway, and reducing PC12 cell apoptosis; however, the effect of α-asarone may be not related to VIP secretion.