Crosstalk between p38 MAPK and GR Signaling

Microglia in radiation-induced brain injury: Cellular and molecular mechanisms and therapeutic potential

BACKGROUND

Radiation-induced brain injury is a neurological condition resulting from radiotherapy for malignant tumors, with its underlying pathogenesis still not fully understood. Current hypotheses suggest that immune cells, particularly the excessive activation of microglia in the central nervous system and the migration of peripheral immune cells into the brain, play a critical role in initiating and progressing the injury. This review aimed to summarize the latest advances in the cellular and molecular mechanisms and the therapeutic potential of microglia in radiation-induced brain injury.

METHODS

This article critically examines recent developments in understanding the role of microglia activation in radiation-induced brain injury. It elucidates associated mechanisms and explores novel research pathways and therapeutic options for managing this condition.

RESULTS

Post-irradiation, activated microglia release numerous inflammatory factors, exacerbating neuroinflammation and facilitating the onset and progression of radiation-induced damage. Therefore, controlling microglial activation and suppressing the secretion of related inflammatory factors is crucial for preventing radiation-induced brain injury. While microglial activation is a primary factor in neuroinflammation, the precise mechanisms by which radiation prompts this activation remain elusive. Multiple signaling pathways likely contribute to microglial activation and the progression of radiation-induced brain injury.

CONCLUSIONS

The intricate microenvironment and molecular mechanisms associated with radiation-induced brain injury underscore the crucial roles of immune cells in its onset and progression. By investigating the interplay among microglia, neurons, astrocytes, and peripheral immune cells, potential strategies emerge to mitigate microglial activation, reduce the release of inflammatory agents, and impede the entry of peripheral immune cells into the brain.

Glucocorticoid receptor and specificity protein 1 (Sp1) or Sp3, but not the antibiotic Mithramycin A, stimulates human alphaherpesvirus 1 (HSV-1) replication

Following acute human alphaherpesvirus 1 (HSV-1) infection of oral-facial mucosal surfaces, sensory neurons in trigeminal ganglia (TG) are important sites for life-long latency. Neurons in the central nervous system, including brainstem, also harbor viral genomes during latency. Periodically, certain cellular stressors trigger reactivation from latency, which can lead to recurrent HSV-1 disease: herpes labialis, herpes stromal keratitis, and encephalitis for example. Activation of the glucocorticoid receptor (GR) by stressful stimuli enhances HSV-1 gene expression, replication, and explant-induced reactivation. GR and certain stress-induced Krüppel like factors (KLF) cooperatively transactivate cis-regulatory modules (CRM) that drive expression of viral transcriptional regulatory proteins (ICP0, ICP4, and ICP27). These CRMs lack GR response elements (GRE); however, specificity protein 1 (Sp1) binding sites are crucial for GR and KLF15 or KLF4 mediated transactivation. Hence, we tested whether Sp1 or Sp3 regulate viral replication and transactivation of the ICP0 promoter. During early stages of explant-induced reactivation from latency, the number of Sp3+ TG neurons were significantly higher relative to TG from latently infected mice. Conversely, Sp1+ TG neurons were only increased in females, but not male mice, during explant-induced reactivation. Sp1 siRNA significantly reduced HSV-1 replication in cultured mouse (Neuro-2A) and monkey (CV-1) cells. Mithramycin A, an antibiotic that has anti-tumor activity preferentially interacts with GC-rich DNA, including Sp1 binding sites, significantly reduced HSV-1 replication indicating it has antiviral activity. GR and Sp1 or Sp3 transactivated the HSV-1 ICP0 promoter in Neuro-2A and CV-1 cells confirming these transcription factors enhance viral replication and gene expression.

Mechanism of Apoptosis in Porcine Ovarian Granulosa Cells Triggered by T-2 Toxin

T-2 toxin (T-2), an A-type mono mycotoxin produced by various Fusarium species, disrupts DNA/RNA and protein synthesis upon entering the body, resulting in pathological conditions in various tissues/organs and posing a significant threat to human and animal health. However, the mechanisms underlying its toxicity remain unclear. With the goal of learning how T-2 affects reproduction in animals, we utilized primary porcine ovarian granulosa cells (pGCs) as a carrier in vitro and constructed concentration models for analyzing cell morphology and RNA-sequencing (RNA-seq). Our findings showed that T-2 could influence pGCs morphology, induce cell cycle arrest, and promote apoptosis in a dose-dependent manner. The results of RNA-seq analyses indicated that a total of 8216 genes exhibited significant differential expression (DEG) following T-2 treatment, of which 4812 were observed to be down-regulated and 3404 were up-regulated. The DEGs following T-2 toxin treatment of pGCs had a notable impact on many metabolic pathways such as PI3K-Akt, Ras, MAPK, and apoptosis, which in turn altered important physiological processes. Gene set enrichment analysis (GSEA) indicated that the differences in the harmful effects of T-2 might be caused by the varying control of cellular processes and the pathway responsible for steroid metabolism. These results present further insights regarding the mechanism of T-2 action on sow reproductive toxicity, enhance our understanding of T-2 reproductive toxicological effects, and lay a theoretical foundation for the judicious prevention of T-2-induced reproductive toxicity.

Scutellarin alleviates tensile stress-induced proliferation and migration of venous smooth muscle cells via mediating the p38 MAPK pathway

OBJECTIVE

Abnormal proliferation and migration of biomechanical force-induced venous smooth muscle cells (VSMCs) is a major cause to limit the efficacy of coronary artery bypass grafting (CABG) for coronary heart disease (CHD). Scutellarin is the main active ingredient of Erigeron Breviscapus, and has broad-spectrum pharmacological effects. Therefore, the present study was proposed to investigate the effect of Scutellarin on VSMCs under tensile stress.

METHODS

After interfering with VSMCs at different tensile stresses, the optimal tensile stress was screened. In a tensile stress environment, 100 μM Scutellarin and Hesperetin (p38 MAPK pathway activator) was used to treatment with VSMCs. CCK-8, EDU, Wound healing, flow cytometry and western blotting assays were used to detect cell proliferation, migration, apoptosis, and the expression of apoptosis-related proteins (Caspase3, Bcl2 and Bax).

RESULTS

Tensile stress with 10% significantly enhanced the activity, wound-healing ratio, and EDU+ cells of VSMCs, and decreased their apoptosis ratio. Moreover, it upregulated Bcl2 expression, and downregulated cleaved-Caspase3 and Bax expression of VSMCs. Hence, 10% tensile stress was selected to creates a tensile stress environment for VSMCs. Interestingly, 100 μM Scutellarin alleviated the effect of 10% tensile stress on the phenotype of VSMCs. Notably, 10% tensile stress increased the phosphorylation level of p38 MAPK (Thr180 +Tyr182) in VSMCs, which was restricted by Scutellarin. Further, Hesperetin restored the effect of Scutellarin on the phenotype of VSMCs.

CONCLUSION

Scutellarin alleviates tension stress-induced proliferation and migration of VSMCs via suppressing p38 MAPK pathway. Scutellarin may be used as an adjunctive strategy for future GABG treatment in CHD patients.

Evodiamine attenuates oxidative stress and ferroptosis by inhibiting the MAPK signaling to improve bortezomib-induced peripheral neurotoxicity

BACKGROUND

Bortezomib (BTZ) is a commonly used antitumor drug, but its peripheral neuropathy side effect poses a limitation on its dosage. Evodiamine (EVO) exhibits various biological activities, including antioxidant, anti-inflammatory, and anticancer effects. The purpose of this investigation is to confirm the impact of EVO on BTZ-induced peripheral neurotoxicity.

METHODS

GeneCards and HERB were applied to analyze the targets of peripheral neurotoxicity and EVO. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis of the hub genes were identified by DAVID. Rat dorsal root ganglion neurons (DRGs) and rat RSC96 Schwann cells (SCs) were treated with BTZ to simulate peripheral neurotoxicity. BTZ-induced peripheral neurotoxicity was assessed by detecting cell viability, proliferation, oxidative stress, and ferroptosis in DRGs and SCs. The mitogen-activated protein kinase (MAPK) signaling was scrutinized by Western blot assay.

RESULTS

The Venn diagram for the overlapping targets of EVO and peripheral neurotoxicity showed that EVO might regulate peripheral neurotoxicity by influencing cell oxidative stress, ferroptosis, and MAPK signaling pathway. EVO attenuated BTZ-induced toxicity in DRGs and SCs. EVO attenuated BTZ-induced oxidative stress damage in DRGs and SCs by reducing reactive oxygen species and malondialdehyde levels and enhancing glutathione level. EVO attenuated BTZ-induced ferroptosis in DRGs and SCs. EVO inhibited BTZ-induced activation of the MAPK signaling in DRGs and SCs. Activation of the MAPK signaling reversed the neuroprotective effect of EVO on BTZ-induced oxidative stress injury and ferroptosis.

CONCLUSION

EVO attenuated oxidative stress and ferroptosis by inhibiting the MAPK signaling to improve BTZ-induced peripheral neurotoxicity.

MAPKs signaling is obligatory for male reproductive function in a development-specific manner

Mitogen-activated protein kinases (MAPKs) represent widely expressed and evolutionarily conserved proteins crucial for governing signaling pathways and playing essential roles in mammalian male reproductive processes. These proteins facilitate the transmission of signals through phosphorylation cascades, regulating diverse intracellular functions encompassing germ cell development in testis, physiological maturation of spermatozoa within the epididymis, and motility regulation at ejaculation in the female reproductive tract. The conservation of these mechanisms appears prevalent across species, including humans, mice, and, to a limited extent, livestock species such as bovines. In Sertoli cells (SCs), MAPK signaling not only regulates the proliferation of immature SCs but also determines the appropriate number of SCs in the testes at puberty, thereby maintaining male fertility by ensuring the capacity for sperm cell production. In germ cells, MAPKs play a crucial role in dynamically regulating testicular cell-cell junctions, supporting germ cell proliferation and differentiation. Throughout spermatogenesis, MAPK signaling ensures the appropriate Sertoli-to-germ cell ratio by regulating apoptosis, controlling the metabolism of developing germ cells, and facilitating the maturation of spermatozoa within the cauda epididymis. During ejaculation in the female reproductive tract, MAPKs regulate two pivotal events-capacitation and the acrosome reaction essential for maintaining the fertility potential of sperm cells. Any disruptions in MAPK pathway signaling possibly may disturb the testicular microenvironment homeostasis, sperm physiology in the male body before ejaculation and in the female reproductive tract during fertilization, ultimately compromising male fertility. Despite decades of research, the physiological function of MAPK pathways in male reproductive health remains inadequately understood. The current review attempts to combine recent findings to elucidate the impact of MAPK signaling on male fertility and proposes future directions to enhance our understanding of male reproductive functions.

Reduction of Th2 inflammation and fibrosis in eosinophilic esophagitis in a murine model by citri reticulatae pericarpium

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammation and subepithelial fibrosis play major roles in the early pathology of eosinophilic esophagitis (EoE). However, there are currently no pharmacotherapeutic interventions that directly target eosinophilic esophagitis. Citri Reticulatae Pericarpium (CRP, known as Chen-Pi) is one of most frequently used qi-regulating drugs in Chinese medicine and nutrition. CRP is rich with flavonones and polymethoxy flavones, both of which exhibit superior anti-inflammatory, anti-allergic and anti-fibrosis effects. This study is to investigate intervention effect of CRP on EoE, to identify its active compounds and to explore its underlying mechanisms.

METHODS

The CRP extract was obtained by liquid-liquid extraction with 70% ethanol, and its main components were identified by HPLC and TLC chromatography as hesperidin, nobiletin, tangeretin, and narirutin in turn. Furthermore, we evaluated its effect and underlying mechanisms in an PN (Peanut protein extract)-sensitized murine model of food allergy induced EoE.

RESULTS

CRP treatment attenuated EoE model mice symptomatology, blocked hypothermia, reduced the production of PN-specific IgE and IgG1 and TH2 cytokines (interleukin (IL)-4 and IL-5), and increased the level of anti-inflammatory cytokines IL-10 and interferon (IFN)-γ. CRP treatment also significantly alleviated the pathological damage and reduced fibrosis in inflamed tissues like esophagus, lung, and intestine. These results were strongly associated with reducing the expression of p-p38 mitogen-activated protein kinase (MAPK), transforming growth factor beta1 (TGF-β1) and p-Smad 3 proteins.

CONCLUSION

CRP extract markedly inhibited TH2 immune response and attenuated subepithelial fibrosis with a dose-dependent manner through down-regulating MAPK/TGF-β signaling pathway. It is suggested that CRP extract might serve as a potential therapy for food allergy-induced EoE like disease.

Natural products for the treatment of depression: Insights into signal pathways influencing the hypothalamic-pituitary-adrenal axis

Depression, a prevalent psychiatric malady, afflicts a substantial global demographic, engendering considerable disease burden due to its elevated morbidity and mortality rates. Contemporary therapeutic approaches for depression encompass the administration of serotonin reuptake inhibitors, monoamine oxidase inhibitors, and tricyclic antidepressants, albeit these pharmaceuticals potentially induce adverse neurological and gastrointestinal effects. Traditional Chinese Medicine (TCM) natural products proffer the benefits of multi-target, multi-level, and multi-channel depression treatment modalities. In this investigation, we conducted a comprehensive literature review of the past 5 years in PubMed and other databases utilizing the search terms "Depression," "Natural medicines," "Traditional Chinese Medicine," and "hypothalamic-pituitary-adrenal axis." We delineated the 5 most recent and pertinent signaling pathways associated with depression and hypothalamic-pituitary-adrenal (HPA) axis dysregulation: nuclear factor kappa light-chain-enhancer of activated B cell, brain-derived neurotrophic factor, mitogen-activated protein kinase, cyclic AMP/protein kinase A, and phosphoinositide 3-kinase/protein kinase B. Additionally, we deliberated the antidepressant mechanisms of natural medicines comprising alkaloids, flavonoids, polyphenols, saponins, and quinones via diverse pathways. This research endeavor endeavored to encapsulate and synthesize the progression of TCMs in modulating HPA axis-associated signaling pathways to mitigate depression, thereby furnishing robust evidence for ensuing research in this domain.

Orcinol glucoside targeted p38 as an agonist to promote osteogenesis and protect glucocorticoid-induced osteoporosis

BACKGROUND

Glucocorticoids (GC)-induced osteoporosis (GIOP) is the most common cause of secondary osteoporosis, which leads to an increased risk of fracture in patients. The inhibition of the osteoblast effect is one of the main pathological characteristics of GIOP, but without effective drugs on treatment.

PURPOSE

The aim of this study was to investigate the potential effects of orcinol glucoside (OG) on osteoblast cells and GIOP mice, as well as the mechanism of the underlying molecular target protein of OG both in vitro osteoblast cell and in vivo GIOP mice model.

METHODS

GIOP mice were used to determine the effect of OG on bone density and bone formation. Then, a cellular thermal shift assay coupled with mass spectrometry (CETSA-MS) method was used to identify the target of OG. Surface plasmon resonance (SPR), enzyme activity assay, molecular docking, and molecular dynamics were used to detect the affinity, activity, and binding site between OG and its target, respectively. Finally, the anti-osteoporosis effect of OG through the target signal pathway was investigated in vitro osteoblast cell and in vivo GIOP mice model.

RESULTS

OG treatment increased bone mineral density (BMD) in GIOP mice and effectively promoted osteoblast proliferation, osteogenic differentiation, and mineralization in vitro. The CETSA-MS result showed that the target of OG acting on the osteoblast is the p38 protein. SPR, molecular docking assay and enzyme activity assay showed that OG could direct bind to the p38 protein and is a p38 agonist. The cellular study found that OG could promote p38 phosphorylation and upregulate the proteins expression of its downstream osteogenic (Runx2, Osx, Collagen Ⅰ, Dlx5). Meanwhile, it could also inhibit the nuclear transport of GR by increasing the phosphorylation site at GR226 in osteoblast cell. In vivo GIOP mice experiment further confirmed that OG could prevent bone loss in the GIOP mice model through promoting p38 activity as well as its downstream proteins expression and activity.

CONCLUSIONS

This study has established that OG could promote osteoblast activity and revise the bone loss in GIOP mice by direct binding to the p38 protein and is a p38 agonist to improve its downstream signaling, which has great potential in GIOP treatment for targeting p38. This is the first report to identify OG anti-osteoporosis targets using a label-free strategy (CETSA-MS).

The mechanisms of minocycline in alleviating ischemic stroke damage and cerebral ischemia-reperfusion injury

Stroke is a group of diseases resulting from cerebral vascular rupture or obstruction and subsequent brain blood circulation disorder, leading to rapid neurological deficits. Ischemic stroke accounts for the majority of all stroke cases. The current treatments for ischemic stroke mainly include t-PA thrombolytic therapy and surgical thrombectomy. However, these interventions aimed at recanalizing cerebral vessels can paradoxically lead to ischemia-reperfusion injury, which exacerbates the severity of brain damage. Minocycline, a semi-synthetic tetracycline antibiotic, has been shown to possess a wide range of neuroprotective effects independent of its antibacterial activity. Here we summarize the mechanisms underlying the protective effects of minocycline against cerebral ischemia-reperfusion injury based on the pathogenesis of cerebral ischemia-reperfusion injury, including its modulation of oxidative stress, inflammatory response, excitotoxicity, programmed cell death and blood-brain barrier injury, and also introduce the role of minocycline in alleviating stroke-related complications, in order to provide a theoretical basis for the clinical application of minocycline in cerebral ischemia-reperfusion injury.

CIRP attenuates acute kidney injury after hypothermic cardiovascular surgery by inhibiting PHD3/HIF-1α-mediated ROS-TGF-β1/p38 MAPK activation and mitochondrial apoptotic pathways

BACKGROUND

The ischemia-reperfusion (IR) environment during deep hypothermic circulatory arrest (DHCA) cardiovascular surgery is a major cause of acute kidney injury (AKI), which lacks preventive measure and treatment. It was reported that cold inducible RNA-binding protein (CIRP) can be induced under hypoxic and hypothermic stress and may have a protective effect on multiple organs. The purpose of this study was to investigate whether CIRP could exert renoprotective effect during hypothermic IR and the potential mechanisms.

METHODS

Utilizing RNA-sequencing, we compared the differences in gene expression between Cirp knockout rats and wild-type rats after DHCA and screened the possible mechanisms. Then, we established the hypothermic oxygen-glucose deprivation (OGD) model using HK-2 cells transfected with siRNA to verify the downstream pathways and explore potential pharmacological approach. The effects of CIRP and enarodustat (JTZ-951) on renal IR injury (IRI) were investigated in vivo and in vitro using multiple levels of pathological and molecular biological experiments.

RESULTS

We discovered that Cirp knockout significantly upregulated rat Phd3 expression, which is the key regulator of HIF-1α, thereby inhibiting HIF-1α after DHCA. In addition, deletion of Cirp in rat model promoted apoptosis and aggravated renal injury by reactive oxygen species (ROS) accumulation and significant activation of the TGF-β1/p38 MAPK inflammatory pathway. Then, based on the HK-2 cell model of hypothermic OGD, we found that CIRP silencing significantly stimulated the expression of the TGF-β1/p38 MAPK inflammatory pathway by activating the PHD3/HIF-1α axis, and induced more severe apoptosis through the mitochondrial cytochrome c-Apaf-1-caspase 9 and FADD-caspase 8 death receptor pathways compared with untransfected cells. However, silencing PHD3 remarkably activated the expression of HIF-1α and alleviated the apoptosis of HK-2 cells in hypothermic OGD. On this basis, by pretreating HK-2 and rats with enarodustat, a novel HIF-1α stabilizer, we found that enarodustat significantly mitigated renal cellular apoptosis under hypothermic IR and reversed the aggravated IRI induced by CIRP defect, both in vitro and in vivo.

CONCLUSION

Our findings indicated that CIRP may confer renoprotection against hypothermic IRI by suppressing PHD3/HIF-1α-mediated apoptosis. PHD3 inhibitors and HIF-1α stabilizers may have clinical value in renal IRI.

Mitochondrial ROS Accumulation Contributes to Maternal Hypertension and Impaired Remodeling of Spiral Artery but Not IUGR in a Rat PE Model Caused by Maternal Glucocorticoid Exposure

Increased maternal glucocorticoid levels have been implicated as a risk factor for preeclampsia (PE) development. We found that pregnant rats exposed to dexamethasone (DEX) showed hallmarks of PE features, impaired spiral artery (SA) remodeling, and elevated circulatory levels of sFlt1, sEng IL-1β, and TNFα. Abnormal mitochondrial morphology and mitochondrial dysfunction in placentas occurred in DEX rats. Omics showed that a large spectrum of placental signaling pathways, including oxidative phosphorylation (OXPHOS), energy metabolism, inflammation, and insulin-like growth factor (IGF) system were affected in DEX rats. MitoTEMPO, a mitochondria-targeted antioxidant, alleviated maternal hypertension and renal damage, and improved SA remodeling, uteroplacental blood flow, and the placental vasculature network. It reversed several pathways, including OXPHOS and glutathione pathways. Moreover, DEX-induced impaired functions of human extravillous trophoblasts were associated with excess ROS caused by mitochondrial dysfunction. However, scavenging excess ROS did not improve intrauterine growth retardation (IUGR), and elevated circulatory sFlt1, sEng, IL-1β, and TNFα levels in DEX rats. Our data indicate that excess mitochondrial ROS contributes to trophoblast dysfunction, impaired SA remodeling, reduced uteroplacental blood flow, and maternal hypertension in the DEX-induced PE model, while increased sFlt1 and sEng levels and IUGR might be associated with inflammation and an impaired energy metabolism and IGF system.

Modeling the Effects of Cypermethrin Toxicity on Ovalbumin-Induced Allergic Pneumonitis Rats: Macrophage Phenotype Differentiation and p38/STAT6 Signaling Are Candidate Targets of Pirfenidone Treatment

Although the classic form of asthma is characterized by chronic pneumonitis with eosinophil infiltration and steroid responsivity, asthma has multifactorial pathogenesis and various clinical phenotypes. Previous studies strongly suggested that chemical exposure could influence the severity and course of asthma and reduce its steroid responsiveness. Cypermethrin (CYP), a common pesticide used in agriculture, was investigated for the possible aggravation of the ovalbumin (OVA)-induced allergic pneumonitis and the possible induction of steroid resistance in rats. Additionally, it was investigated whether pirfenidone (PFD) could substitute dexamethasone, as an alternative treatment option, for the induced steroid resistance. Fifty-six male Wistar albino rats were randomly divided into seven groups: control, PFD alone, allergic pneumonitis, CYP alone, allergic pneumonitis/CYP-exposed, allergic pneumonitis/CYP/dexamethasone (Dex), and allergic pneumonitis/CYP/PFD-treated groups. Allergic pneumonitis was induced by three intraperitoneal OVA injections administered once a week, followed by an intranasal OVA instillation challenge. CYP (25 mg/kg/d), Dex (1 mg/kg/d), and PFD (100 mg/kg/d) were administered orally from day 15 to the end of the experiment. Bronchoalveolar lavage fluid (BALF) was analyzed for cytokine levels. Hematoxylin and eosin (H&E) and periodic acid Schiff (PAS)-stained lung sections were prepared. Immunohistochemical identification of p38 MAPK and lung macrophages was performed. The inflammatory/oxidative status of the lung and PCR-quantification of the STAT6, p38 MAPK, MUC5AC, and IL-13 genes were carried out. The allergic pneumonitis-only group showed eosinophil-mediated inflammation (p < 0.05). Further CYP exposure aggravated lung inflammation and showed steroid-resistant changes, p38 activation, neutrophil-mediated, M1 macrophage-related inflammation (p < 0.05). All changes were reversed (p < 0.05) by PFD, meanwhile not by dexamethasone treatment. Pirfenidone could replace dexamethasone treatment in the current rat model of CYP-induced severe steroid-resistant asthma via inhibiting the M1 macrophage differentiation through modulation of the STAT6/p38 MAPK pathway.

Nuclear receptor modulators inhibit osteosarcoma cell proliferation and tumour growth by regulating the mTOR signaling pathway

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Chemoresistance leads to poor responses to conventional therapy in patients with osteosarcoma. The discovery of novel effective therapeutic targets and drugs is still the main focus of osteosarcoma research. Nuclear receptors (NRs) have shown substantial promise as novel therapeutic targets for various cancers. In the present study, we performed a drug screen using 29 chemicals that specifically target 17 NRs in several different human osteosarcoma and osteoblast cell lines. The retinoic acid receptor beta (RARb) antagonist LE135, peroxisome proliferator activated receptor gamma (PPARg) antagonist T0070907, liver X receptor (LXR) agonist T0901317 and Rev-Erba agonist SR9011 significantly inhibited the proliferation of malignant osteosarcoma cells (U2OS, HOS-MNNG and Saos-2 cells) but did not inhibit the growth of normal osteoblasts. The effects of these NR modulators on osteosarcoma cells occurred in a dose-dependent manner and were not observed in NR-knockout osteosarcoma cells. These NR modulators also significantly inhibited osteosarcoma growth in vivo and enhanced the antitumour effect of doxorubicin (DOX). Transcriptomic and immunoblotting results showed that these NR modulators may inhibit the growth of osteosarcoma cells by regulating the PI3K/AKT/mTOR and ERK/mTOR pathways. DDIT4, which blocks mTOR activation, was identified as one of the common downstream target genes of these NRs. DDIT4 knockout significantly attenuated the inhibitory effects of these NR modulators on osteosarcoma cell growth. Together, our results revealed that modulators of RARb, PPARg, LXRs and Rev-Erba inhibit osteosarcoma growth both in vitro and in vivo through the mTOR signaling pathway, suggesting that treatment with these NR modulators is a novel potential therapeutic strategy.

Expression patterns of AMPK and genes associated with lipid metabolism in newly hatched chicks during the metabolic perturbation of fasting and refeeding

Fasting–refeeding perturbation has been extensively used to reveal specific genes and metabolic pathways that control energy metabolism in chickens. In this study, 200 chickens were randomly assigned to 2 groups after hatching: the control group (C, fed ad libitum) and the fasting–refeeding group (T, water ad libitum). The chicks in Group T were fasted for 72 h, and then fed for another 48 h. Liver, hypothalamus, and adipose samples were collected at 0 (F0), 24 (F24), 48 (F48), and 72 h (F72) after fasting and 4 (FR4), 12 (FR12), 24 (FR24), and 48 h (FR48) after refeeding, respectively. Results showed that Group T had a significantly higher number of liver vacuoles (P < 0.05 or P < 0.01) and a significantly lower gray value of Sudan IIIstained sections (P < 0.05 or P < 0.01) than Group C at F48–FR48. In addition, compared with the Group C, fasting and refeeding reduced the expression of stearoyl CoA desaturase (SCD) mRNA (P < 0.05 or P < 0.01) in the liver and adipose tissues, the expression of glucocorticoid receptor (GR) mRNA (P < 0.05 or P < 0.01) in the liver, adipose, and hypothalamus tissues, and the expression of fatty acid synthase (FAS) mRNA (P < 0.05 or P < 0.01) in the liver at F24–FR24. Moreover, relative to those in Group C, fasting and refeeding increased the mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK) α, AMPKβ, and AMPKγ in the hypothalamus (P < 0.05 or P < 0.01) at F24–FR24. In conclusion, fasting and refeeding increased the fat content of the liver, and the expression of lipolytic genes in the hypothalamus (e.g., AMPKα, AMPKβ, and AMPKγ) but decreased the expression of fat synthesis genes in the liver (e.g., SCD, GR, and FAS), adipose (SCD and GR), and hypothalamus (GR).

Intermittent Hypoxia on the Attenuation of Induced Nasal Allergy and Allergic Asthma by MAPK Signaling Pathway Downregulation in a Mice Animal Model

Intermittent hypoxia (IH) has been an issue of considerable research in recent years and triggers a bewildering array of both detrimental and beneficial effects in several physiological systems. However, the mechanisms leading to the effect are not yet clear. Consequently, we investigated the effects of IH on allergen-induced allergic asthma via the mitogen-activated protein kinase (MAPK) signaling pathway. Forty BALB/c mice were dived into four groups. We evaluated the influence of IH on the cell signaling system of the airway during the allergen-induced challenge in an animal model, especially through the MAPK (mitogen-activated protein kinase) pathway. The protein concentrations of p-ERK/ERK, p-JNK/JNK, p-p38/p38, and pMEK/MEK were significantly reduced in the allergen-induced+IH group, compared to the allergen-induced group (p-value < 0.05 as considered statistically significant). The number of eosinophils, neutrophils, macrophages, and lymphocytes in the bronchoalveolar lavage fluid and Dp (Dermatophagoides pteronyssinus)-specific IgG2a and interleukins 4, 5, 13, and 17 were significantly reduced in the Dp+IH group, compared to the Dp group. These findings suggest that the MAPK pathway might be associated with the beneficial effect of IH on the attenuation of allergic response in an allergen-induced mouse model.

Cinnamomum zeylanicum Extract and its Bioactive Component Cinnamaldehyde Show Anti-Tumor Effects via Inhibition of Multiple Cellular Pathways

Cinnamomum zeylanicum is a tropical plant with traditional medicinal significance that possesses antimicrobial, antifungal, anti-parasitic, and anti-tumor properties. Here, we have elucidated the anti-tumor effects of Cinnamomum zeylanicum extract (CZE) and its bioactive compound cinnamaldehyde (CIN) on oral cancer and elucidated underlying molecular mechanisms. Anti-tumor activities of CZE and CIN were demonstrated by various in vitro experiments on oral cancer cells (SCC-4, SCC-9, SCC-25). The cell proliferation, growth, cell cycle arrest, apoptosis, and autophagy were analyzed by MTT, clonogenic assay, propidium iodide, annexin-V-PI, DAPI, and acridine orange staining, respectively. The binding affinity of CIN towards dihydrofolate reductase and p38-MAP kinase alpha was analyzed by molecular docking. Western blot assay was performed to assess the alteration in the expression of various proteins. CZE and CIN treatment significantly inhibited the growth and proliferation of oral cancer cells in a dose-dependent manner. These treatments further induced apoptosis, cell cycle arrest, and autophagy. CZE and CIN inhibited the invasion and cytoplasmic translocation of NF-κB in these cell lines. CIN showed a high affinity to MAP kinase P38 alpha and dihydrofolate reductase with binding affinities of −6.8 and −5.9 kcal/mol, respectively. The cancer cells showed a decreased expression of various PI3k-AKT-mTOR pathways related to VEGF, COX-2, Bcl-2, NF-κB, and proteins post-treatment.