REV-ERBα integrates colon clock with experimental colitis through regulation of NF-κB/NLRP3 axis

Ji-Ming-San enhances intestinal circadian rhythms and mitigates colitis in mice: The role of epithelial RORα

BACKGROUND

Ji-Ming-San (JMS), a traditional Chinese medicine, exhibits time-dependent pharmacological effects, suggesting its potential as a circadian clock modulator. However, the precise mechanisms by which JMS regulates circadian rhythms remain unclear.

PURPOSE

This study aims to elucidate how JMS influences the local circadian clock machinery, and move beyond association to mechanistic discovery.

METHODS

A jet lag model of circadian disruption was used to assess the regulatory effects of JMS on circadian behavior and clock gene expression. The impact of JMS on clock genes was examined in colon epithelial cells. Non-targeted metabolomics was utilized to identify key components and potential pathways. Network pharmacology, molecular docking, Gal4 co-transfection assays, and RNA sequencing were conducted to explore potential JMS targets. Chromatin immunoprecipitation assays were performed to investigate the transcriptional regulation mechanisms.

RESULTS

JMS restored circadian rhythms in locomotor activity and intestinal clock gene expression in jet-lagged mice. Under colitis conditions, JMS reduced pathological severity and inflammation in mice with circadian disruption by upregulating BMAL1 and PER2. In mice with normal circadian rhythms, the protective effect of JMS was observed during the remission phase of colitis. At the cellular level, JMS activated RORα and enhanced the transcription and expression of BMAL1 and PER2 in colonic epithelial cells. Metabolomics and RNA sequencing revealed that JMS inhibited NF-κB signaling, contributing to its anti-inflammatory action. Mechanistically, JMS enhanced RORα/HDAC3 binding to NF-κB target genes in epithelial cells, leading to reduced H3K9Ac levels and repression of Il-1β and Tnf-α, while epithelial RORα knockdown abolished the anti-inflammatory effects.

CONCLUSION

This study demonstrates that JMS activates epithelial RORα to restore circadian rhythm in the colon and suppresses NF-κB signaling, ultimately promoting colitis recovery These findings underscore the role of JMS in regulating intestinal circadian rhythm and highlight its potential as a chronotherapeutic strategy for colitis.

Tea residue protein-derived oligopeptides attenuate DSS-induced acute colitis complicated with hepatic injury in C57BL/6J mice by regulating the gut-microbiome-liver axis

BACKGROUND

Impairment of the intestinal mucosal barrier is a prevalent feature of acute colitis, and untreated acute colitis can lead to extra-intestinal manifestations, including hepatic injury. Previous research has demonstrated that large-leaf yellow tea residue protein-derived oligopeptides (TPP) can alleviate ulcerative colitis symptoms and hepatic injury in mice. However, the underlying regulatory mechanisms by which TPP improves colitis complicated with liver injury are unknown.

PURPOSE

To explore the potential mechanism by which TPP alleviates acute colitis complicated with hepatic injury.

METHODS

Acute colitis with hepatic injury was induced in mice using 3.5 % dextran sodium sulfate. Both 16S rRNA sequencing and transcriptomic analyses were utilized to investigate the impact of TPP on mitigating symptoms in mice.

RESULTS

It indicated that TPP administration effectively reduced inflammatory symptoms in the colon and liver, enhanced the secretion of mucin occluding, claudin-1, ZO-1, and MUC-2, decreased intestinal mucosal permeability, and restored homeostasis within the gut microbiome of mice. Moreover, transcriptomic analysis has evidenced the effectiveness of TPP in mitigating liver-related effects. RNA-seq KEGG enrichment and RT-qPCR analyses validated TPP could modulate the "gut-microbiome-liver" axis, and participate in signaling pathways related to inflammatory regulation, as well as bile acid metabolism and synthesis.

CONCLUSION

These findings suggest that TPP administration is a promising novel approach for preventing and treating acute colitis complicated with hepatic injury.

Cold-Induced RNA-Binding Protein (CIRP) Affects Cerebral Ischemia-Reperfusion Injury Through NF-κB Pathway

The pathological and physiological mechanisms for effectively mitigating ischemia-reperfusion (I/R) injury and preserving brain structure and function remain unclear. This study investigates the regulatory mechanism underlying cold-induced RNA-binding protein (CIRP)-mediated NF-κB pathway in cerebral I/R injury and neuronal inflammatory injury. The infarct volume of I/R CIRP-/- mice was significantly mitigated, and the inflammatory factor IL-18 expression in mice serum and the NLRP3 and IL-1β expression in brain tissue was significantly decreased as opposed to the I/R WT mice. The in vitro outcomes manifested that inhibiting CIRP expression led to a significant hindrance in cell apoptosis, a significant drop in the inflammatory factors levels in the cell supernatant, and a significant decline in the expression of pyroptosis-linked proteins ASC, cleaved caspase-1, and gasdermin D (GSDMD) in cells. Following administration of the NF-κB pathway inhibitor PDTC, there was a significant hindrance in cell apoptosis, as well as a significant drop in the inflammatory factors levels IL-1β, TNF-α, and IL-18 in the cell supernatant. After treating BV-2 cells with HT22 cell conditioned medium under OGD condition, the content of LDH in BV-2 cells was increased. Intervention of CIRP expression in HT22 cells resulted in reduced damage to BV-2 cells and decreased expression of M1 marker CD86. CIRP may be involved in neuronal damage in I/R and in vitro OGD models via the NF-κB /NLRP3 pathway, and it may affect microglial polarization.

A circadian clock controls the daily function of the intestine in rainbow trout. Influence of light and food as synchronizers

Environmental factors (daily light/dark cycles, food availability, etc.) entrain endogenous oscillators in living organisms, thereby allowing them to control the rhythms of behavioral and physiological functions, such as energy homeostasis. The gastrointestinal tract (GIT) is the first site of nutrient contact upon food intake. Thus, the GIT is key in energy homeostasis. Circadian oscillators exist within the GIT of mammals, modulating the daily function of the tissue. However, little information in this respect is available for other vertebrates, such as fish. Thus, we aimed to confirm the presence of a circadian oscillator within the GIT of rainbow trout (Oncorhynchus mykiss) and its interaction with locally released hormones that participate in feeding regulation in this species. We subsequently evaluated the role of food and light in synchronizing the rhythmic functioning of the GIT. According to our results, a circadian oscillator exists throughout the GIT of rainbow trout, based on the daily rhythms of clock gene (clock1a, bmal1b, per1, cry2 and reb-ervβ-like) mRNA abundance. Light influences the function of the circadian oscillator within the GIT, but food is a key factor as a synchronizer. The feeding time and the presence and/or absence of food synchronize the rhythmic function of the GIT, as observed for GIT hormones (Ghrelin, Glp1 and Cck). Understanding the functioning of the circadian machinery in peripheral organs such as the GIT will ultimately help to improve different aspects of aquaculture, from farming strategies to welfare, among others.

Anti-Inflammatory Effects of Spexin on Acetic Acid‑Induced Colitis in Rats via Modulating the NF-κB/NLRP3 Inflammasome Pathway

Ulcerative colitis is a chronic inflammatory bowel disease characterized by inflammation and ulcers in the lining of the colon and rectum. Spexin is a novel peptide with antioxidant and anti-inflammatory properties. This study aims to elucidate the therapeutic effects and underlying mechanisms of spexin in mitigating acetic acid-induced colitis in rats. Male Sprague Dawley rats were assigned to control (n = 14) and colitis (n = 21) groups. Colitis was induced via 5% acetic acid (AA) administration (1 mL, intrarect). Post-induction, rats received subcutaneous saline (1 mL/kg), spexin (50 µg/kg/day), or oral sulfasalazine (500 mg/kg) for 5 days. Control groups received saline or spexin. After 24 h of the final treatment, colons were evaluated macroscopically, and levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-18 were determined by ELISA, oxidative stress markers myeloperoxidase (MPO), malondialdehyde (MDA) and glutathione (GSH) levels were measured spectrophotometrically and NOD-like receptor pyrin domain-containing 3 (NLRP3), nuclear factor-κB (NF-κB), caspase-1 proteins were analyzed with Western Blot alongside histopathological assessments. Colitis induction significantly elevated macroscopic damage scores, stool consistency, inflammatory cytokines, MDA, MPO, and NLRP3, NF-κB, caspase-1, while reducing GSH levels (p < 0.001-0.01). Microscopic evaluations confirmed increased necrosis, submucosal edema, and inflammatory cell infiltration (p < 0.001). Spexin reversed these effects by enhancing GSH levels (p < 0.01), reducing macroscopic/microscopic scores, cytokines, MDA, and MPO levels (p < 0.05-0.001), and suppressing NLRP3, NF-κB, and caspase-1 activation (p < 0.01-0.001). For the first time that spexin ameluates acetic acid-induced colitis in rats by modulating the NF-κB/NLRP3 signaling pathway, reducing oxidative damage, enhancing antioxidant capacity, and suppressing inflammation.

Genetic disruption of the circadian gene Bmal1 in the intestinal epithelium reduces colonic inflammation

Disruption of the circadian clock is associated with the development of inflammatory bowel disease (IBD), but the underlying mechanisms remain unclear. Here, we observe that mice in the early active phase (Zeitgeber time 12, ZT12) of the circadian clock are more tolerant to dextran sodium sulfate (DSS)-induced colitis, compared to those in the early resting phase (ZT0). The expression of the circadian gene Bmal1 peaks in the early resting phase and declines in the early active phase. Bmal1 knockout in the intestinal epithelium reduces DSS-induced inflammatory symptoms. Mechanistically, BMAL1 promotes apoptosis by binding to apoptosis-related genes, including Bax, p53, and Bak1, and promotes their expression. Intriguingly, we observe circadian apoptotic rhythms in the homeostatic intestinal epithelium, while Bmal1 deletion reduces cell apoptosis. Consistently, reducing Bmal1 expression by the REV-ERBα agonist SR9009 has the best therapeutic efficacy against DSS-induced colitis at ZT0. Collectively, our data demonstrate that the Bmal1-centered circadian clock is involved in intestinal injury repair.

CMTM3 Promotes Colitis-associated Carcinogenesis Via CLTC Stabilization and Modulation of VE-cadherin

BACKGROUND & AIMS

Inflammatory bowel disease leads to increased risk of developing colitis-associated colon cancer (CAC). CMTM3 has a higher methylation level in colon cancer, and accumulating evidence suggests that chemokine-like factor-like MARVEL transmembrane domain-containing member 3 (CMTM3) participates in inflammation and cancer development.

METHODS

We explored the signs of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced CAC in wild-type (WT) and Cmtm3 deficiency (Cmtm3-/-) mice. Experimental colitis was induced in Cmtm3-/- mice as well as mice with endothelial cell-specific deletion of Cmtm3. Disease phenotypes were investigated by body weight, disease activity index (DAI), colon length, histology, immune cell infiltration, and intestinal permeability. The mechanism was analyzed using bone marrow reconstitution, immunofluorescent staining, Western blot, immunoprecipitation, and pull-down experiments.

RESULTS

We found CMTM3 promoted CAC by aggravating colitis. Further, we revealed endothelial cell-specific deletion of Cmtm3 inhibited the colitis development. In vitro and in vivo mechanistic studies revealed that CMTM3 drove colitis by increasing clathrin-dependent downregulation of vascular endothelial-cadherin, thus causing vascular permeability. We further identified that CMTM3 interacted with clathrin heavy chain and inhibited clathrin heavy chain ubiquitination and proteasome-dependent degradation. Interestingly, Cmtm3 knockout and imatinib mesylate both targeted vascular permeability and had comparable efficacy.

CONCLUSIONS

Our study indicates that CMTM3 promotes CAC by aggravating colitis through causing vascular permeability, providing insights into targets for development of future therapies.

Regulation of cyclophosphamide induced hepatotoxicity by REV-ERBα modifiers

INTRODUCTION

Cyclophosphamide (CPA) is a widely used broad-spectrum antitumor drug with severe hepatotoxicity. Finding an effective way to mitigate the hepatotoxicity caused by CPA is a challenge in its clinical application.

METHODS

In Rev-erbα knockout and wild-type mice, hepatotoxicity was evaluated by ALT, AST, and histopathological scores 4-h post dose of CPA (i.p. 300 mg/kg). CYP2B10 expression and pharmacokinetic behavior of CPA were also detected. SR9009 (i.p. 10 mg/kg) and Berberine (BBR, i.p. 50 mg/kg) were pre-administered to mice. Then, the measurements were carried out following the same procedures as previous. The regulation effects of SR9009 and BBR on CYP2B10 were validated using Hepa-1c1c7 cells.

RESULTS

Firstly, REV-ERBα negatively regulated CPA-induced hepatotoxicity by altering the expression of CYP2B10 and CPA pharmacokinetics. Secondly, REV-ERBα agonists, SR9009 and BBR, increased REV-ERBα expression and alleviated hepatic toxicity of CPA. Furthermore, both SR9009 and BBR reduced expression of CYP2B10 and REV-ERBα target gene Bmal1 both in vivo and in vitro.

CONCLUSIONS

REV-ERBα agonists can significantly attenuate the hepatotoxicity of CPA by regulating CYP2B10. The discovery of REV-ERBα as novel regulator for CYP2B10 will help to establish new targets to improve drug efficacy or reduce toxicity.

High-Resolution Tracking of Aging-Related Small Molecules: Bridging Pollutant Exposure, Brain Aging Mechanisms, and Detection Innovations

Brain aging is a complex process regulated by genetic, environmental, and metabolic factors, and increasing evidence suggests that environmental pollutants can significantly accelerate this process by interfering with oxidative stress, neuroinflammation, and mitochondrial function-related signaling pathways. Traditional studies have focused on the direct damage of pollutants on macromolecules (e.g., proteins, DNA), while the central role of senescence-associated small molecules (e.g., ROS, PGE2, lactate) in early regulatory mechanisms has been long neglected. In this study, we innovatively proposed a cascade framework of "small molecule metabolic imbalance-signaling pathway dysregulation-macromolecule collapse", which reveals that pollutants exacerbate the dynamics of brain aging through activation of NLRP3 inflammatory vesicles and inhibition of HIF-1α. Meanwhile, to address the technical bottleneck of small molecule spatiotemporal dynamics monitoring, this paper systematically reviews the cutting-edge detection tools such as electrochemical sensors, genetically encoded fluorescent probes and antioxidant quantum dots (AQDs). Among them, AQDs show unique advantages in real-time monitoring of ROS fluctuations and intervention of oxidative damage by virtue of their ultra-high specific surface area, controllable surface modification, and free radical scavenging ability. By integrating multimodal detection techniques and mechanism studies, this work provides a new perspective for analyzing pollutant-induced brain aging and lays a methodological foundation for early intervention strategies based on small molecule metabolic networks.

Closed-loop theranostic microgels for immune microenvironment modulation and microbiota remodeling in ulcerative colitis

Inflammatory bowel disease (IBD) is characterized by the upregulation of reactive oxygen species (ROS) and dysfunction of gut immune system, and microbiota. The conventional treatments mainly focus on symptom control with medication by overuse of drugs. There is an urgent need to develop a closed-loop strategy that combines in situ monitoring and precise treatment. Herein, we innovatively designed the 'cluster munition structure' theranostic microgels to realize the monitoring and therapy for ulcerative colitis (a subtype of IBD). The superoxide anion specific probe (tetraphenylethylene-coelenterazine, TPC) and ROS-responsive nanogels consisting of postbiotics urolithin A (UA) were loaded into alginate and ion-crosslinked to obtain the theranostic microgels. The theranostic microgels could be delivered to the inflammatory site, where the environment-triggered breakup of the microgels and release of the nanogels were achieved in sequence. The TPC-UA group had optimal results in reducing inflammation, repairing colonic epithelial tissue, and remodeling microbiota, leading to inflammation amelioration and recovery of tight junction between the colonic epithelium, and maintenance of gut microbiota. During the recovery process, the local chemiluminescence intensity, which is proportional to the degree of inflammation, was gradually inhibited. The cluster munition of theranostic microgels displayed promising outcomes in monitoring inflammation and precise therapy, and demonstrated the potential for inflammatory disease management.

Circadian Rhythm Disruption Exacerbates Autoimmune Uveitis: The Essential Role of PER1 in Treg Cell Metabolic Support for Stability and Function

Circadian rhythm plays a critical role in the progression of autoimmune diseases. While our previous study demonstrated the therapeutic effects of melatonin in experimental autoimmune uveitis, the involvement of circadian rhythm remained unclear. Using a light-induced circadian rhythm disruption model, we showed that disrupted circadian rhythms exacerbate autoimmune uveitis by impairing the stability and function of Treg cells. Mechanistically, we identified the core clock gene Per1, which is significantly reduced under circadian disruption, is essential for Treg cell metabolism and immunoregulatory function. This study underscores the pivotal role of circadian rhythm-related Treg cells in autoimmune disease progression.

Circadian disruption by simulated shift work aggravates periodontitis via orchestrating BMAL1 and GSDMD-mediated pyroptosis

Approximately 20% to 30% of the global workforce is engaged in shift work. As a significant cause of circadian disruption, shift work is closely associated with an increased risk for periodontitis. Nevertheless, how shift work-related circadian disruption functions in periodontitis remains unknown. Herein, we employed a simulated shift work model constructed by controlling the environmental light-dark cycles and revealed that shift work-related circadian disruption exacerbated the progression of experimental periodontitis. RNA sequencing and in vitro experiments indicated that downregulation of the core circadian protein brain and muscle ARNT-like protein 1 (BMAL1) and activation of the Gasdermin D (GSDMD)-mediated pyroptosis were involved in the pathogenesis of that. Mechanically, BMAL1 regulated GSDMD-mediated pyroptosis by suppressing NOD-like receptor protein 3 (NLRP3) inflammasome signaling through modulating nuclear receptor subfamily 1 group D member 1 (NR1D1), and inhibiting Gsdmd transcription via directly binding to the E-box elements in its promoter. GSDMD-mediated pyroptosis accelerated periodontitis progression, whereas downregulated BMAL1 under circadian disruption further aggravated periodontal destruction by increasing GSDMD activity. And restoring the level of BMAL1 by circadian recovery and SR8278 injection alleviated simulated shift work-exacerbated periodontitis via lessening GSDMD-mediated pyroptosis. These findings provide new evidence and potential interventional targets for circadian disruption-accelerated periodontitis.

Pharmacological targets and therapeutic mechanisms of Arabic gum in treating diabetic wounds: insights from network pharmacology and experimental validation

Background and objectives

On account of the long-term inflammatory microenvironment, diabetic wounds are challenging to heal in which advanced glycation end products are considered important factors hindering the healing of diabetic wounds. Gum Arabic has demonstrated significant potential in the treatment of various diseases owing to its anti-inflammatory and antioxidant properties. Nonetheless, there is still insufficient research on the role of Arabic gum in facilitating diabetic wounds healing and its mechanisms. This study aims to investigate the pharmacological targets and therapeutic mechanisms of Arabic Gum on diabetic wound healing by adopting network pharmacology, molecular docking, and experimental validation.

Methods

Key active components of Arabic Gum and disease targets were identified through network pharmacology and bioinformatics. GO/KEGG enrichment was performed to identify critical pathways. Cytoscape and AutoDock were used for targets prediction and molecular docking validation. In vitro, Transwell assay and tube formation assay were performed to evaluate the effect of Arabic Gum on human fibroblasts migration and human umbilical vein endothelial cells angiogenesis. Western blotting analyzed Pro-caspase-1, ASC, NLRP3 and NF-κB pathway-related proteins. In vivo, a full-thickness diabetic wound model was established. Histological changes were assessed via H&E and Masson's staining, oxidative stress levels through DHE staining, inflammation levels with IL-1β, CD68 and CD206 staining, angiogenesis and cell proliferation levels were assessed by CD31 and Ki67 staining. The levels of pathway-related proteins were analyzed by NLRP3 and Phospho-NF-κB P65 staining.

Results

Network pharmacology analysis identified key targets, encompassing HSP90AA1, STAT3, and PRKCB, involved in the AGEs-NF-κB-NLRP3 signaling axis. Molecular docking demonstrated strong binding affinity between AG components and these targets. In vitro, AG lessened AGEs-induced activation of the NLRP3 inflammasome via modulation of the NF-κB pathway and reinforced cell migration and angiogenesis. In vivo, AG-treated diabetic wounds exhibited accelerated healing, with augmented collagen deposition, lowered oxidative stress and inflammation, and strengthened cell migration and angiogenesis. AG promotes diabetic wound healing by modulating the AGEs-NF-κB-NLRP3 axis, exerting anti-inflammatory, antioxidant, pro-angiogenic, and cell-proliferative effects.

Conclusion

This study provides new insights into diabetic wound repair and suggests that AG is a promising therapeutic agent for improving diabetic wound healing.

REV-ERBα Inhibits Osteoclastogenesis and Protects against Alveolar Bone Loss

Circadian rhythm disruption is thought to be associated with periodontitis, and molecular clock genes play critical roles in regulating bone homeostasis. However, the specific contribution of molecular clock genes to alveolar bone resorption caused by periodontitis is poorly understood. In this study, we introduced a novel Periodontitis Circadian Rhythm Score (PeriCRS) model that was established through machine learning using periodontal transcriptomic data from periodontitis clinical cohorts in the Gene Expression Omnibus (GEO) database. This approach revealed the potential regulatory role of circadian rhythm disruption in periodontitis and identified key molecular clock genes associated with alveolar bone destruction. Moreover, we established an experimental periodontitis model with circadian rhythm disturbance via periodontal ligation in mice exposed to a 6-h advanced LD12:12 cycle every 2 d. Our bioinformatics analysis revealed that NR1D1, which encodes REV-ERBα, is a pivotal factor in the impact of circadian rhythm disruption on periodontitis in periodontal tissues. Next, we confirmed the abnormal expression of the molecular clock gene Rev-erbα in inflammatory periodontal tissue in mice and confirmed that circadian rhythm disruption altered REV-ERBα expression. Furthermore, the activation of REV-ERBα with the agonist SR9009 notably decreased RANKL-induced osteoclast differentiation and suppressed the expression of osteoclast-related factors. Subsequent in vivo experiments demonstrated that SR9009 mitigated alveolar bone loss caused by periodontitis. Mechanistically, we found that the IL-22-STAT3 pathway inhibited REV-ERBα expression and modulated RANKL-induced osteoclast differentiation in vitro. Our results elucidate the role of REV-ERBα in osteoclastogenesis and suggest a potential new therapeutic avenue for addressing alveolar bone resorption associated with periodontitis.

Triptolide attenuates LPS-induced chondrocyte inflammation by inhibiting inflammasome activation via the Wnt/β-catenin and NF-κB signaling pathways

Osteoarthritis (OA) is a common form of arthritis characterized by subchondral bone proliferation and articular cartilage degeneration. Recently, the Nod-like receptor pyrin domain 3 (NLRP3) inflammasome has gained attention due to its association with synovial inflammation in OA. Triptolide (TP), known for its immunosuppressive and anti-inflammatory effects, has been studied in various diseases. However, the specific impact of TP on OA and its underlying mechanism remains largely unexplored. In this study, chondrocytes were treated with a specific concentration of TP, and subsequent analysis through Western blotting and immunofluorescence staining revealed decreased expression levels of MMP-13, NLRP3, Caspase-1, ASC, β-catenin, p-p65, and IκB compared to the model group. ELISA results demonstrated significantly lower levels of IL-1β, IL-18, and TNF-α in the TP treatment group compared to the model group. In addition, triptolide ameliorates the degradation of the extracellular matrix (ECM) by enhancing the expression of collagen-II. In conclusion, our findings suggest that TP exhibits anti-inflammatory effects on chondrocytes in the presence of LPS-induced inflammation by inhibiting the activation of the NLRP3 inflammasome via the Wnt/β-catenin and NF-κB pathway. These results contribute to a better understanding of TP's potential therapeutic benefits in managing OA.

Basic helix-loop-helix ARNT like 1 regulates the function of immune cells and participates in the development of immune-related diseases

The circadian clock is an internal timekeeper system that regulates biological processes through a central circadian clock and peripheral clocks controlling various genes. Basic helix-loop-helix ARNT-like 1 (BMAL1), also known as aryl hydrocarbon receptor nuclear translocator-like protein 1 (ARNTL1), is a key component of the circadian clock. The deletion of BMAL1 alone can abolish the circadian rhythms of the human body. BMAL1 plays a critical role in immune cell function. Dysregulation of BMAL1 is linked to immune-related diseases such as autoimmune diseases, infectious diseases, and cancer, and vice versa. This review highlights the significant role of BMAL1 in governing immune cells, including their development, differentiation, migration, homing, metabolism, and effector functions. This study also explores how dysregulation of BMAL1 can have far-reaching implications and potentially contribute to the onset of immune-related diseases such as autoimmune diseases, infectious diseases, cancer, sepsis, and trauma. Furthermore, this review discusses treatments for immune-related diseases that target BMAL1 disorders. Understanding the impact of BMAL1 on immune function can provide insights into the pathogenesis of immune-related diseases and help in the development of more effective treatment strategies. Targeting BMAL1 has been demonstrated to achieve good efficacy in immune-related diseases, indicating its promising potential as a targetable therapeutic target in these diseases.

Curcumin attenuates ulcerative colitis via regulation of Sphingosine kinases 1/NF-κB signaling pathway

Curcumin, a compound from Curcuma longa L., has significant anti-inflammatory properties. However, the mechanisms underlying its anti-inflammatory activity in dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) remain inadequately understood. This study aimed to further elucidate the molecular mechanisms of curcumin DSS-induced UC mice. Our data showed that curcumin alleviated DSS-induced colitis by reducing intestinal damage and inflammation, increasing goblet cells in colon tissues. Enzyme-linked immunosorbent assay revealed that curcumin reduced the expression of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1β, and interleukin-8) in serum and myeloperoxidase in colon tissues. A comprehensive analysis integrating network pharmacology and RNA sequencing (RNA-seq) revealed significant enrichment of the nuclear factor kappa B (NF-κB) signaling pathways. Notably, RNA-seq analysis demonstrated that curcumin significantly downregulated the mRNA expression of sphingosine kinase 1 (SphK1). Furthermore, molecular docking analysis showed that curcumin can bind to SphK1 and NF-κB. Additionally, curcumin was found to inhibit the activation of the SphK1/NF-κB signaling pathway in DSS-induced UC colon tissue. This study addresses pharmacologic and mechanistic perspectives of curcumin that ameliorates DSS-induced UC and inflammatory response.

Time-restricted feeding modulates gene expression related with rhythm and inflammation in Mongolian gerbils

Time-restricted feeding (TRF) has the potential to modulate circadian rhythm and widely studied in humans and laboratory mice. However, less is known about the physiological responses to TRF in wild mammals. Here, we used Mongolian gerbils, Meriones unguiculatus, to explore the effect of 6-week TRF on gene expression related with circadian rhythm and inflammation. The TRF gerbils had higher cumulative food intake than the ad libitum (AL) group, but body mass, feeding frequency/time and metabolic rate did not differ between groups. In the hypothalamus, downregulation of rhythm-related genes Per3, Cry1 and Dbp was detected in the daytime-restricted feeding (DRF) group and Cry1 was downregulated in the nighttime-restricted feeding (NRF) group. In the liver, the expression of Per1/3, Rev-erbα/β and Dbp was lower, and Bmal1 was higher in the DRF than in AL group, while NRF gerbils showed no changes. In the colon, the expression of Bmal1 and Cry1 was higher but Per3, Rev-erbα/β and Dbp were lower in the DRF than in AL group. Further, the expression of inflammation-related genes such as NF-κB, IL-1β, IL-18 and Nlrp3 was lower in the liver of DRF gerbils, and IL-1β was lower both in the hypothalamus and liver of NRF gerbils. Moreover, the genes related with inflammation such as NF-κB, Nlrp3, IL-10/18/1β and Tnf-α were positively or negatively correlated with multiple rhythm-related genes in the central and peripheral organs. In conclusion, TRF, particularly DRF, could modulate rhythm-related genes in the central and peripheral tissues and reduce hepatic expression of inflammation-related genes in gerbils.

Time-of-day control of mitochondria regulates NLRP3 inflammasome activation in macrophages

Macrophages are innate immune cells that orchestrate the process of inflammation, which varies across time of day. This ensures appropriate biological timing of the immune response with the external environment. The NLRP3 inflammasome mediates IL-1-family cytokine release via pyroptosis. Mitochondria play a multifaceted role regulating NLRP3 inflammasome activity. Mitochondria exhibit distinct metabolic changes across time of day, which are influenced by clock genes. However, whether the macrophage clock regulates the NLRP3 inflammasome via mitochondrial control remains unclear. We find heightened mitochondrial membrane potential (Δψm) and enhanced NLRP3 inflammasome activation from peritoneal exudate cells (PECs) isolated at circadian time (CT) 12 compared to CT 0. In vitro time-of-day synchronization of bone-marrow derived macrophages (BMDMs) induced time-dependent differences in NLRP3 inflammasome activation. Myeloid-specific Bmal1-deletion enhanced NLRP3 inflammasome activity in PECs at CT0 and in unsynchronized BMDMs compared to controls. Pharmacologically disrupting Δψm in synchronized cells reduced NLRP3 inflammasome activation to comparable levels, and the same occurred with Bmal1-deletion. These results further demonstrate circadian clock timing of the NLRP3 inflammasome, which is dependent on mitochondrial function and driven through the circadian gene Bmal1.

The circadian clock in inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) involve relapsing-remitting immune activation and inflammation. Both immune system activity and digestive tract function exhibit diurnal variations, regulated by the circadian clock. Disruption of this clock is linked to inflammation, suggesting that circadian regulators may play a pivotal role in the inflammatory process of IBD.

Peptostreptococcus Anaerobius enhances dextran sulfate sodium-induced colitis by promoting nf-κB-NLRP3-Dependent macrophage pyroptosis

Evidence indicates that gut microbiota is crucial in ulcerative colitis (UC) development. Increased Peptostreptococcus species abundance is linked to UC, but its role and mechanisms in intestinal inflammation are not well understood. This study used a dextran sulfate sodium (DSS)-induced colitis model in mice, and different bacterial strains were administered via gavage. We assessed clinical manifestations, colonic barrier function, gut microbiota composition, and levels of inflammatory cytokines, NOD-like receptor family pyrin domain-containing 3 (NLRP3) signaling molecules, and pyroptosis-related proteins. Mouse bone marrow-derived macrophages (BMDMs) were infected with Peptostreptococcus anaerobius at different time points and multiplicities of infection (MOI). Cell viability and the expression of NLRP3 signaling molecules and pyroptosis-associated proteins were assessed. The inhibitors C29, TAK-242, and MCC950 were employed for Toll-like receptor (TLR) and NLRP3 signaling pathways. It was observed that P. anaerobius exacerbated intestinal inflammation and barrier injury in DSS-induced colitis in mice. Additionally, P. anaerobius contributed to gut microbiota dysbiosis during colitis progression. P. anaerobius induced the expression of NLRP3 signaling molecules and pyroptosis-associated proteins in mouse colitis tissues. In vitro assays demonstrated that P. anaerobius activated NLRP3 inflammasome and evoked gasdermin D-mediated pyroptosis and interleukin (IL)-1β secretion in macrophages. Furthermore, TLR2 and TLR4 were identified as key mediators of P. anaerobius-induced macrophage pyroptosis via activation of the Nuclear Factor-kappa B (NF-κB)-NLRP3 pathway. In conclusion, P. anaerobius promotes macrophage pyroptosis and IL-1β secretion through the TLR2/4-NF-κB-NLRP3 signaling axis, thereby aggravating colitis. P. anaerobius may represent a potential risk factor for UC development.

Inflammation o'clock: interactions of circadian rhythms with inflammation-induced skeletal muscle atrophy

Circadian rhythms are ∼24 h cycles evident in behaviour, physiology and metabolism. The molecular mechanism directing circadian rhythms is the circadian clock, which is composed of an interactive network of transcription-translation feedback loops. The core clock genes include Bmal1, Clock, Rev-erbα/β, Per and Cry. In addition to keeping time, the core clock regulates a daily programme of gene expression that is important for overall cell homeostasis. The circadian clock mechanism is present in all cells, including skeletal muscle fibres, and disruption of the muscle clock is associated with changes in muscle phenotype and function. Skeletal muscle atrophy is largely associated with a lower quality of life, frailty and reduced lifespan. Physiological and genetic modification of the core clock mechanism yields immune dysfunction, alters inflammatory factor expression and secretion and is associated with skeletal muscle atrophy in multiple conditions, such as ageing and cancer cachexia. Here, we summarize the possible interplay between the circadian clock modulation of immune cells, systemic inflammatory status and skeletal muscle atrophy in chronic inflammatory conditions. Although there is a clear disruption of circadian clocks in various models of atrophy, the mechanism behind such alterations remains unknown. Understanding the modulatory potential of muscle and immune circadian clocks in inflammation and skeletal muscle health is essential for the development of therapeutic strategies to protect skeletal muscle mass and function of patients with chronic inflammation.

Nuclear receptor Rev-erbα alleviates intervertebral disc degeneration by recruiting NCoR-HDAC3 co-repressor and inhibiting NLRP3 inflammasome

Intervertebral discs (IVDs) are rhythmic tissues that experience daily low-load recovery. Notably, aging and abnormal mechanical stress predispose IVDs to degeneration due to dysrhythmia-induced disordered metabolism. Meanwhile, Rev-erbα acts as a transcriptional repressor in maintaining biorhythms and homeostasis; however, its function in IVD homeostasis and degeneration remains unclear. This study assessed the relationship between low Rev-erbα expression levels and IVD degeneration. Rev-erbα deficiency accelerated needle puncture or aging-induced IVD degeneration, characterized by increased extracellular matrix (ECM) catabolism and nucleus pulposus (NP) cell apoptosis. Mechanistically, Rev-erbα knockdown in NP cells aggravated rhIL1β-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation, exacerbating the imbalanced ECM and NP cell apoptosis. Meanwhile, blocking NLRP3 inflammasome activation mitigated Rev-erbα deficiency and needle puncture-induced IVD degeneration. Particularly, Rev-erbα mediated the transcriptional repression of the NLRP3 inflammasome via the ligand heme-binding of nuclear receptor co-repressor (NCoR) and histone deacetylase 3 (HDAC3) complex. Thus, the increased expression of Rev-erbα in NP cells following short-term rhIL1β treatment failed to inhibit NLRP3 transcription in vitro owing to heme depletion. Pharmacological activation of Rev-erbα in vivo and in vitro alleviated IVD degeneration by altering the NLRP3 inflammasome. Taken together, targeting Rev-erbα may be a potential therapeutic strategy for alleviating IVD degeneration and its related diseases.

Parenteral nutrition results in peripheral ileal to hepatic circadian discordance in mice

We have developed a mouse model of parenteral nutrition-associated liver disease (PNALD) in which parenteral nutrition (PN) infusion results in cholestatic liver injury. In the liver, the master circadian genes Arntl/Bmal drive rhythmic gene expression and regulate circadian expression of hepatic functions including bile acid synthesis. The aim of this study was to examine the effect of continuous PN on ileal and hepatic expression of circadian regulatory (CR) genes, farnesoid X receptor (FXR) signaling, and bile acid synthesis in mice. Wild-type mice were exposed to ad libitum Chow or continuous soy oil lipid emulsion-based PN infusion through a central venous catheter for 4 days (PN). Water was provided ad libitum, but no nutrients were provided enterally. On day 4, separate groups of Chow and PN-fed mice were euthanized every 6 h (7 AM, 1 PM, 7 PM, and 1 AM), and ileal, hepatic tissue and serum harvested. From tissue samples, the relative expression of circadian transcription factors and FXR signaling was assessed. Administration of 4-day PN increased hepatic injury, inflammatory cytokine expression, and gut permeability. In the ileum, PN activated FXR and induced expression of Fgf15 and Nr0b2. In the liver, expression of FXR-downstream targets was dysregulated. PN administrations impacted hepatic and ileal circadian transcription factor mRNA expression, which was discordant between the two organs. Dysregulation of circadian regulatory machinery is in part due to discordance of the gut-liver axis during PN. Pharmacological targeting of CR as a therapeutic strategy for PNALD thus deserves further investigation.NEW & NOTEWORTHY This study used a novel short-term model of parenteral nutrition (PN) that is translationally relevant. We find that short-term PN is sufficient to induce hepatic and ileal changes in circadian transcription factor expression and to prevent normal concordant coordination of circadian transcription factors between the ileum and liver. These data suggest that targeting circadian transcription may have some clinical benefit in patients receiving parenteral nutrition.

NR1D1 activation alleviates inflammatory response through inhibition of IL-6 expression in bovine endometrial epithelial cells

Endometritis, an inflammatory disease affecting dairy cattle, causes substantial economic losses in the dairy industry. Conventional treatment using uterine infusion of antibiotics often results in bacterial resistance and antibiotic residues in milk. Thus, identifying novel, effective therapeutic targets for endometritis in dairy cows is necessary. Nuclear receptor subfamily 1 group D member 1 (NR1D1) activation attenuates inflammatory responses in various diseases through transcriptional repression; however, its role in treating bovine endometritis remains unclear. This study investigated the role and underlying mechanisms of NR1D1 in endometritis using a bovine endometrial epithelial cell line (BENDs) and primary bovine endometrial epithelial cells, both induced with Escherichia coli lipopolysaccharide (LPS). Immunofluorescence staining revealed the predominant nuclear localization of NR1D1 in endometrial epithelial cells. LPS treatment (1 μg/mL for 12 h) significantly increased the expression levels of NR1D1 and proinflammatory cytokines (IL-6, IL-1β, IL-8, and CCL5) in BENDs. Immunohistochemical staining showed elevated NR1D1 expression in uterine tissues of cows with endometritis. Deletion of NR1D1 significantly increased IL-6 mRNA expression; NR1D1 overexpression substantially repressed IL-6 expression in BENDs. NR1D1 agonist SR9009 attenuated LPS-induced mRNA expression of proinflammatory cytokines (IL-6, IL-1β, CCL5) in both BENDs and primary endometrial epithelial cells. Additionally, SR9009 treatment attenuated LPS-induced inflammatory responses in the endometrium of mice. Dual-luciferase reporter assays and real-time monitoring via luminescence assays showed that NR1D1 overexpression significantly repressed luciferase activity driven by the IL-6 promoter region, which was abolished by deletion of the retinoic acid receptor-related orphan receptor-responsive element (-473 to -479) within the IL-6 promoter fragment. In summary, NR1D1 activation alleviates the inflammatory response of BENDs by repressing the expression of proinflammatory cytokines, at least partly via IL-6, suggesting NR1D1 is a promising therapeutic target for endometritis prevention and treatment.

Circadian disruption in cancer hallmarks: Novel insight into the molecular mechanisms of tumorigenesis and cancer treatment

Circadian rhythms are 24-h rhythms governing temporal organization of behavior and physiology generated by molecular clocks composed of autoregulatory transcription-translation feedback loops (TTFLs). Disruption of circadian rhythms leads to a spectrum of pathologies, including cancer by triggering or being involved in different hallmarks. Clock control of phenotypic plasticity involved in tumorigenesis operates in aberrant dedifferentiating to progenitor-like cell states, generation of cancer stem cells (CSCs) and epithelial-to-mesenchymal transition (EMT) events. Circadian rhythms might act as candidates for regulatory mechanisms of cellular senescent and functional determinants of senescence-associated secretory phenotype (SASP). Reciprocal control between clock and epigenetics sheds light on post-transcriptional regulation of circadian rhythms and opens avenues for novel anti-cancer strategies. Additionally, disrupting circadian rhythms influences microbiota communities that could be associated with altered homeostasis contributing to cancer development. Herein, we summarize recent advances in support of the nexus between disruptions of circadian rhythms and cancer hallmarks of new dimensions, thus providing novel perspectives on potentially effective treatment approaches for cancer management.

Ginsenoside Rb1 Alleviates DSS-Induced Ulcerative Colitis by Protecting the Intestinal Barrier Through the Signal Network of VDR, PPARγ and NF-κB

Purpose

Ginseng (Panax ginseng Meyer) is an herbal medicine used in traditional Chinese medicine (TCM), has the effects of treating colitis and other diseases. Ginsenoside Rb1 (GRb1), a major component of ginseng, modulates autoimmunity and metabolism. However, the mechanism underlying GRb1 treatment of ulcerative colitis (UC) has not yet been elucidated. UC is a refractory inflammatory bowel disease (IBD) with a high recurrence rate, and researches on new drugs for UC have been in the spotlight for a long time.

Methods

Mice with DSS-induced UC were treated with GRb1 or 0.9% saline for 10 days. Colon tissue of UC mice was collected to detect the levels of intestinal inflammatory cytokines and integrity of the intestinal barrier. RNA-seq and network pharmacology were used to predict the therapeutic targets of GRb1 during UC treatment.

Results

GRb1 treatment alleviated intestinal inflammation and improved intestinal barrier dysfunction in UC mice. Specifically, GRb1 downregulated the levels of pro-inflammatory cytokines such as TNF-α and IL-6, while upregulating the level of the anti-inflammatory cytokine IL-10. Additionally, GRb1 treatment increased the levels of tight junction proteins including ZO-1, Occludin, and E-cadherin, which are crucial for maintaining intestinal barrier integrity. Further analyses using RNA-seq and network pharmacology suggested that these effects might involve the regulation of GRb1 in the signal transduction network of VDR, PPARγ, and NF-κB.

Conclusion

The study demonstrated that GRb1 effectively alleviated UC by modulating intestinal inflammation and protecting the integrity of the intestinal barrier through the signal transduction network of VDR, PPARγ, and NF-κB.

Circadian rhythm disruption modulates enteric neural precursor cells differentiation leading to gastrointestinal motility dysfunction via the NR1D1/NF-κB axis

OBJECTIVES

Circadian rhythm disruption (CRD) is implicated with numerous gastrointestinal motility diseases, with the enteric nervous system (ENS) taking main responsibility for the coordination of gastrointestinal motility. The purpose of this study is to explore the role of circadian rhythms in ENS remodeling and to further elucidate the underlying mechanisms.

METHODS

First, we established a jet-lagged mice model by advancing the light/dark phase shift by six hours every three days for eight weeks. Subsequent changes in gastrointestinal motility and the ENS were then assessed. Additionally, a triple-transgenic mouse strain (Nestin-creERT2 × Ngfr-DreERT2: DTRGFP) was utilized to track the effects of CRD on the differentiation of enteric neural precursor cells (ENPCs). RNA sequencing was also performed to elucidate the underlying mechanism.

RESULTS

Compared to the control group, CRD significantly accelerated gastrointestinal motility, evidenced by faster intestinal peristalsis (P < 0.01), increased fecal output (P < 0.01), and elevated fecal water content (P < 0.05), as well as enhanced electrical field stimulation induced contractions (P < 0.05). These effects were associated with an increase in the number of glial cells and nitrergic neurons in the colonic myenteric plexus. Additionally, ENPCs in the colon showed a heightened differentiation into glial cells and nitrergic neurons. Notably, the NR1D1/nuclear factor-kappaB (NF-κB) axis played a crucial role in the CRD-mediated changes in ENPCs differentiation. Supplementation with NR1D1 agonist or NF-κB antagonist was able to restore gastrointestinal motility and normalize the ENS in jet-lagged mice.

CONCLUSIONS

CRD regulates the differentiation of ENPCs through the NR1D1/NF-κB axis, resulting in dysfunction of the ENS and impaired gastrointestinal motility in mice.

Interferon regulatory factor 7 alleviates the experimental colitis through enhancing IL-28A-mediated intestinal epithelial integrity

BACKGROUND

The incidence of inflammatory bowel disease (IBD) is on the rise in developing countries, and investigating the underlying mechanisms of IBD is essential for the development of targeted therapeutic interventions. Interferon regulatory factor 7 (IRF7) is known to exert pro-inflammatory effects in various autoimmune diseases, yet its precise role in the development of colitis remains unclear.

METHODS

We analyzed the clinical significance of IRF7 in ulcerative colitis (UC) by searching RNA-Seq databases and collecting tissue samples from clinical UC patients. And, we performed dextran sodium sulfate (DSS)-induced colitis modeling using WT and Irf7-/- mice to explore the mechanism of IRF7 action on colitis.

RESULTS

In this study, we found that IRF7 expression is significantly reduced in patients with UC, and also demonstrated that Irf7-/- mice display heightened susceptibility to DSS-induced colitis, accompanied by elevated levels of colonic and serum pro-inflammatory cytokines, suggesting that IRF7 is able to inhibit colitis. This increased susceptibility is linked to compromised intestinal barrier integrity and impaired expression of key molecules, including Muc2, E-cadherin, β-catenin, Occludin, and Interleukin-28A (IL-28A), a member of type III interferon (IFN-III), but independent of the deficiency of classic type I interferon (IFN-I) and type II interferon (IFN-II). The stimulation of intestinal epithelial cells by recombinant IL-28A augments the expression of Muc2, E-cadherin, β-catenin, and Occludin. The recombinant IL-28A protein in mice counteracts the heightened susceptibility of Irf7-/- mice to colitis induced by DSS, while also elevating the expression of Muc2, E-cadherin, β-catenin, and Occludin, thereby promoting the integrity of the intestinal barrier.

CONCLUSION

These findings underscore the pivotal role of IRF7 in preserving intestinal homeostasis and forestalling the onset of colitis.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Circadian time-dependent effects of experimental colitis on theophylline disposition and toxicity

BACKGROUND AND PURPOSE

Drug disposition undergoes significant alteration in patients with inflammatory bowel disease (IBD), yet circadian time-dependency of these changes remains largely unexplored. In this study, we aimed to determine the temporal effects of experimental colitis on drug disposition and toxicity.

EXPERIMENTAL APPROACH

RNA-sequencing was used to screen genes relevant to colitis induced by dextran sodium sulfate in mice. Liver microsomes and pharmacokinetic analysis were used to analyze the activity of key enzymes. Dual luciferase assays and chromatin immunoprecipitation (ChIP) were employed to elucidate regulatory mechanisms.

KEY RESULTS

RNA sequencing analysis revealed that colitis markedly influenced expression of cytochrome P450 (CYP) enzymes. Specifically, a substantial down-regulation of CYP1A2 and CYP2E1 was observed in livers of mice with colitis at Zeitgeber Time 8 (ZT8), with no significant changes detected at ZT20. At ZT8, the altered expression corresponded to diminished metabolism and enhanced incidence of hepato-cardiac toxicity of theophylline, a substrate specifically metabolized by these enzymes. A combination of assays, integrating liver-specific Bmal1 knockout and targeted activation of BMAL1 showed that dysregulation in CYP1A2 and CYP2E1 during colitis was attributable to perturbed BMAL1 functionality. Luciferase reporter and ChIP assays collectively substantiated the role of BMAL1 in regulating Cyp1a2 and Cyp2e1 transcription through its binding affinity to E-box-like sites.

CONCLUSION AND IMPLICATION

Our findings establish a strong link between colitis and chronopharmacology, shedding light on how IBD affects drug disposition and toxicity over time. This research provides a theoretical foundation for optimizing drug dosage in patients with IBD.

MiR-146a-5p engineered hucMSC-derived extracellular vesicles attenuate Dermatophagoides farinae-induced allergic airway epithelial cell inflammation

INTRODUCTION

Allergic asthma is prevalent in children, with Dermatophagoides farinae as a common indoor allergen. Current treatments for allergic airway inflammation are limited and carry risks. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) show promise as a cell-free therapeutic approach. However, the use of engineered MSC-EVs for D. farinae-induced allergic airway epithelial cell inflammation remains unexplored.

METHODS

We generated miR-146a-5p-engineered EVs from human umbilical cord mesenchymal stem cells (hucMSCs) and established D. farinae-induced mouse and human bronchial epithelial cell allergic models. Levels of IL-1β, IL-18, IL-4, IL-5, IL-6, IL-10, IL-33, TNF-α and IgE were detected using ELISA. The relative TRAF6 and IRAK1 mRNA expression was quantified using qPCR assay and the NLRP3, NF-κB, IRAK1 and TRAF6 protein expression was determined using Western blotting. The regulatory effect of IRAK1 and TRAF6 by miR-146a-5p was examined using a dual luciferase reporter assay, and the nuclear translocation of NF-κB p65 into 16-HBE cells was evaluated using immunofluorescence assay.

RESULTS

Treatment with hucMSC-EVs effectively reduced allergic inflammation, while miR-146a-5p engineered hucMSC-EVs showed greater efficacy. The enhanced efficacy in alleviating allergic airway inflammation was attributed to the downregulation of IRAK1 and TRAF6 expression, facilitated by miR-146a-5p. This downregulation subsequently led to a decrease in NF-κB nuclear translocation, which in turn resulted in reduced activation of the NLRP3 inflammasome and diminished production of inflammatory cytokines, including IL-6, TNF-α, IL-1β and IL-18.

CONCLUSION

Our study underscores the potential of miR-146a-5p engineered hucMSC-EVs as a cell-free therapeutic strategy for D. farinae-induced allergic airway inflammation, offering a promising avenue for boosting anti-inflammatory responses.

A New Frontier in Cystic Fibrosis Pathophysiology: How and When Clock Genes Can Affect the Inflammatory/Immune Response in a Genetic Disease Model

Cystic fibrosis (CF) is a monogenic syndrome caused by variants in the CF Transmembrane Conductance Regulator (CFTR) gene, affecting various organ and systems, in particular the lung, pancreas, sweat glands, liver, gastrointestinal tract, vas deferens, and vascular system. While for some organs, e.g., the pancreas, a strict genotype-phenotype occurs, others, such as the lung, display a different pathophysiologic outcome in the presence of the same mutational asset, arguing for genetic and environmental modifiers influencing severity and clinical trajectory. CFTR variants trigger a pathophysiological cascade of events responsible for chronic inflammatory responses, many aspects of which, especially related to immunity, are not ascertained yet. Although clock genes expression and function are known modulators of the innate and adaptive immunity, their involvement in CF has been only observed in relation to sleep abnormalities. The aim of this review is to present current evidence on the clock genes role in immune-inflammatory responses at the lung level. While information on this topic is known in other chronic airway diseases (chronic obstructive pulmonary disease and asthma), CF lung disease (CFLD) is lacking in this knowledge. We will present the bidirectional effect between clock genes and inflammatory factors that could possibly be implicated in the CFLD. It must be stressed that besides sleep disturbance and its mechanisms, there are not studies directly addressing the exact nature of clock genes' involvement in inflammation and immunity in CF, pointing out the directions of new and deepened studies in this monogenic affection. Importantly, clock genes have been found to be druggable by means of genetic tools or pharmacological agents, and this could have therapeutic implications in CFLD.

Nasal solitary chemosensory cells govern daily rhythm in mouse model of allergic rhinitis

BACKGROUND

While the daily rhythm of allergic rhinitis (AR) has long been recognized, the molecular mechanism underlying this phenomenon remains enigmatic.

OBJECTIVE

We aimed to investigate the role of circadian clock in AR development and to clarify the mechanism by which the daily rhythm of AR is generated.

METHODS

AR was induced in mice with ovalbumin. Toluidine blue staining, liquid chromatography-tandem mass spectrometry analysis, real-time quantitative PCR, and immunoblotting were performed with AR and control mice.

RESULTS

Ovalbumin-induced AR is diurnally rhythmic and associated with clock gene disruption in nasal mucosa. In particular, Rev-erbα is generally downregulated and its rhythm retained, but with a near-12-hour phase shift. Furthermore, global knockout of core clock gene Bmal1 or Rev-erbα increases the susceptibility of mice to AR and blunts AR rhythmicity. Importantly, nasal solitary chemosensory cells (SCCs) are rhythmically activated, and inhibition of the SCC pathway leads to attenuated AR and a loss of its rhythm. Moreover, rhythmic activation of SCCs is accounted for by diurnal expression of ChAT (an enzyme responsible for the synthesis of acetylcholine) and temporal generation of the neurotransmitter acetylcholine. Mechanistically, Rev-erbα trans-represses Chat through direct binding to a specific response element, generating a diurnal oscillation in this target gene.

CONCLUSION

SCCs, under the control of Rev-erbα, are a driver of AR rhythmicity; targeting SCCs should be considered as a new avenue for AR management.

Aegeline attenuates TNBS-induced colitis by suppressing the NFƙB-mediated NLRP3 inflammasome pathway in mice

A chronic inflammatory condition of the intestine, ulcerative colitis (UC), is challenging to successfully manage once diagnosed. Currently, available medical therapies for UC exhibit minimal efficacy with unacceptable side effects, while inventive biological agents are expensive and yet not well accepted by patients. Discovering more effective and safer treatments to treat UC is therefore essential. One of the primary alkaloids found in Aegle marmelos, aegeline, has anti-inflammatory and antioxidant properties as well as being able to suppress several pro-inflammatory cytokines responsible for inflammation. The study aimed to investigate the effectiveness of aegeline in alleviating 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis through the NFƙB-mediated NLRP3 inflammasome pathway. Mice were randomly allocated into six groups, Normal control (NC), Model control (MC-TNBS, 2,4,6-trinitrobenzene sulfonic acid), STD (TNBS + sulfasalazine 100 mg/kg), AG1, AG2, and AG3 (TNBS + aegeline 5, 10, 20 mg/kg) respectively. Physical parameters such as a change in body weight, stool consistency, rectal bleeding, colon length, myeloperoxidase (MPO) levels and nitric oxide (NO) levels, and disease activity index (DAI) were assessed and supporting gene expression studies of various pro-inflammatory cytokines and enzymes were evaluated and histopathological changes observed. Administration of aegeline (10, 20 mg/kg) was found to be effective in colon protection by lowering the disease activity score and myeloperoxidase level and improving other physical parameters. Aegeline in high dose significantly downregulated the gene expression of NFƙB, iNOS, COX-2, NLRP3, IL-1β, and IL-18, conferring great anti-inflammatory potential. Suggestive of the findings, aegeline reduced the damage to the colon by downregulating transcriptional genes and enzymes leading to inflammation and mitigated TNBS-induced colitis probably through the NFƙB-mediated NLRP3 inflammasome pathway.

Circadian rhythms and cardiac physiology: An essential interplay

Virtually every cell in the human body contains a molecular circadian clock that orchestrates the rhythmic oscillations of a multitude of tissue-specific functions. This is evident in the heart, where circadian rhythms are seen in various cardiac functions. Genetic disruption of clock genes has underscored their significance in regulating multiple aspects of cardiac physiology. In this review, we report the principal findings regarding the impact of clock gene manipulation (whole body or cardiomyocyte specific) on cardiac function. Furthermore, we present the current knowledge on the circadian clock in the different cell populations in the heart-cardiomyocytes, endothelial cells, fibroblasts, and immune cells. While increasing studies have shown mechanistic links between core clock components and cardiomyocytes-specific genes, the information of clock function within other cardiac cells in the heart is extremely limited. This review underlines the need to gain more information on the temporal segregation of clock processes in cardiac-especially in non-cardiomyocytes-cells, as clock-controlled mechanism may be target of chronotherapy to optimize current treatments for cardiovascular diseases.

Regulation of hepatocyte phospholipid peroxidation signaling by a Chinese patent medicine against psychological stress-induced liver injury

BACKGROUND

Psychological stress is associated with various diseases including liver dysfunction, yet effective intervention strategies remain lacking due to the unrevealed pathogenesis mechanism.

PURPOSE

This study aims to explore the relevance between BMAL1-controlled circadian rhythms and lipoxygenase 15 (ALOX15)-mediated phospholipids peroxidation in psychological stress-induced liver injury, and to investigate whether hepatocyte phospholipid peroxidation signaling is involved in the hepatoprotective effects of a Chinese patent medicine, Pien Tze Huang (PZH).

METHODS

Restraint stress models were established to investigate the underlying molecular mechanisms of psychological stress-induced liver injury and the hepatoprotective effects of PZH. Redox lipidomics based on liquid chromatography-tandem mass spectrometry was applied for lipid profiling.

RESULTS

The present study discovered that acute restraint stress could induce liver injury. Notably, lipidomic analysis confirmed that phospholipid peroxidation was accumulated in the livers of stressed mice. Additionally, the essential core circadian clock gene Brain and Muscle Arnt-like Protein-1 (Bmal1) was altered in stressed mice. Circadian disruption in mice, as well as BMAL1-overexpression in human HepaRG cells, also appeared to have a significant increase in phospholipid peroxidation, suggesting that stress-induced liver injury is closely related to circadian rhythm and phospholipid peroxidation. Subsequently, arachidonate 15-lipoxygenase (ALOX15), a critical enzyme that contributed to phospholipid peroxidation, was screened as a potential regulatory target of BMAL1. Mechanistically, BMAL1 promoted ALOX15 expression via direct binding to an E-box-like motif in the promoter. Finally, this study revealed that PZH treatment significantly relieved pathological symptoms of psychological stress-induced liver injury with a potential mechanism of alleviating ALOX15-mediated phospholipid peroxidation.

CONCLUSION

Our findings illustrate the critical role of BMAL1-triggered phospholipid peroxidation in psychological stress-induced liver injury and provide new insight into treating psychological stress-associated liver diseases by TCM intervention.

IRF7 Exacerbates Candida albicans Infection by Compromising CD209-Mediated Phagocytosis and Autophagy-Mediated Killing in Macrophages

IFN regulatory factor 7 (IRF7) exerts anti-infective effects by promoting the production of IFNs in various bacterial and viral infections, but its role in highly morbid and fatal Candida albicans infections is unknown. We unexpectedly found that Irf7 gene expression levels were significantly upregulated in tissues or cells after C. albicans infection in humans and mice and that IRF7 actually exacerbates C. albicans infection in mice independent of its classical function in inducing IFNs production. Compared to controls, Irf7-/- mice showed stronger phagocytosis of fungus, upregulation of C-type lectin receptor CD209 expression, and enhanced P53-AMPK-mTOR-mediated autophagic signaling in macrophages after C. albicans infection. The administration of the CD209-neutralizing Ab significantly hindered the phagocytosis of Irf7-/- mouse macrophages, whereas the inhibition of p53 or autophagy impaired the killing function of these macrophages. Thus, IRF7 exacerbates C. albicans infection by compromising the phagocytosis and killing capacity of macrophages via regulating CD209 expression and p53-AMPK-mTOR-mediated autophagy, respectively. This finding reveals a novel function of IRF7 independent of its canonical IFNs production and its unexpected role in enhancing fungal infections, thus providing more specific and effective targets for antifungal therapy.

Circadian rhythm disruption-mediated downregulation of Bmal1 exacerbates DSS-induced colitis by impairing intestinal barrier

Background

Circadian rhythm disruption (CRD) is thought to increase the risk of inflammatory bowel disease. The deletion of Bmal1, a core transcription factor, leads to a complete loss of the circadian rhythm and exacerbates the severity of dextran sodium sulfate (DSS)-induced colitis in mice. However, the underlying mechanisms by which CRD and Bmal1 mediate IBD are still unclear.

Methods

We used a CRD mouse model, a mouse colitis model, and an in vitro model of colonic epithelial cell monolayers. We also knocked down and overexpressed Bmal1 in Caco-2 cells by transfecting lentivirus in vitro. The collected colon tissue and treated cells were assessed and analyzed using immunohistochemistry, immunofluorescence staining, quantitative reverse transcription-polymerase chain reaction, western blot, flow cytometry, transmission electron microscopy, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling staining.

Results

We found that CRD mice with downregulated Bmal1 expression were more sensitive to DSS-induced colitis and had more severely impaired intestinal barrier function than wild-type mice. Bmal1-/- mice exhibited more severe colitis, accompanied by decreased tight junction protein levels and increased apoptosis of intestinal epithelial cells compared with wild-type mice, which were alleviated by using the autophagy agonist rapamycin. Bmal1 overexpression attenuated Lipopolysaccharide-induced apoptosis of intestinal epithelial cells and impaired intestinal epithelial cells barrier function in vitro, while inhibition of autophagy reversed this protective effect.

Conclusion

This study suggests that CRD leads to the downregulation of Bmal1 expression in the colon, which may exacerbate DSS-induced colitis in mice, and that Bmal1 may serve as a novel target for treating inflammatory bowel disease.

Circadian Control of the Response of Macrophages to Plasmodium Spp.-Infected Red Blood Cells

Malaria is a serious vector-borne disease characterized by periodic episodes of high fever and strong immune responses that are coordinated with the daily synchronized parasite replication cycle inside RBCs. As immune cells harbor an autonomous circadian clock that controls various aspects of the immune response, we sought to determine whether the intensity of the immune response to Plasmodium spp., the parasite causing malaria, depends on time of infection. To do this, we developed a culture model in which mouse bone marrow-derived macrophages are stimulated with RBCs infected with Plasmodium berghei ANKA (iRBCs). Lysed iRBCs, but not intact iRBCs or uninfected RBCs, triggered an inflammatory immune response in bone marrow-derived macrophages. By stimulating at four different circadian time points (16, 22, 28, or 34 h postsynchronization of the cells' clock), 24-h rhythms in reactive oxygen species and cytokines/chemokines were found. Furthermore, the analysis of the macrophage proteome and phosphoproteome revealed global changes in response to iRBCs that varied according to circadian time. This included many proteins and signaling pathways known to be involved in the response to Plasmodium infection. In summary, our findings show that the circadian clock within macrophages determines the magnitude of the inflammatory response upon stimulation with ruptured iRBCs, along with changes of the cell proteome and phosphoproteome.

Circadian-clock-controlled endocrine and cytokine signals regulate multipotential innate lymphoid cell progenitors in the bone marrow

Innate lymphoid cells (ILCs), strategically positioned throughout the body, undergo population declines over time. A solution to counteract this problem is timely mobilization of multipotential progenitors from the bone marrow. It remains unknown what triggers the mobilization of bone marrow ILC progenitors (ILCPs). We report that ILCPs are regulated by the circadian clock to emigrate and generate mature ILCs in the periphery. We found that circadian-clock-defective ILCPs fail to normally emigrate and generate ILCs. We identified circadian-clock-controlled endocrine and cytokine cues that, respectively, regulate the retention and emigration of ILCPs at distinct times of each day. Activation of the stress-hormone-sensing glucocorticoid receptor upregulates CXCR4 on ILCPs for their retention in the bone marrow, while the interleukin-18 (IL-18) and RORα signals upregulate S1PR1 on ILCPs for their mobilization to the periphery. Our findings establish important roles of circadian signals for the homeostatic efflux of bone marrow ILCPs.

SR9009 attenuates inflammation-related NPMSC pyroptosis and IVDD through NR1D1/NLRP3/IL-1β pathway

Intervertebral disc is a highly rhythmical tissue. As a key factor linking biorhythm and inflammatory response, the shielding effect of NR1D1 in the process of intervertebral disc degeneration remains unclear. Here, we first confirmed that NR1D1 in the nucleus pulposus tissue presents periodic rhythmic changes and decreases in expression with intervertebral disc degeneration. Second, when NR1D1 was activated by SR9009 in vitro, NLRP3 inflammasome assembly and IL-1β production were inhibited, while ECM synthesis was increased. Finally, the vivo experiments further confirmed that the activation of NR1D1 can delay the process of disc degeneration to a certain extent. Mechanistically, we demonstrate that NR1D1 can bind to IL-1β and NLRP3 promoters, and that the NR1D1/NLRP3/IL-1β pathway is involved in this process. Our results demonstrate that the activation of NR1D1 can effectively reduce IL-1β secretion, alleviate LPS-induced NPMSC pyroptosis, and protect ECM degeneration.

Timosaponin BⅡ reduces colonic inflammation and alleviates DSS-induced ulcerative colitis by inhibiting NLRP3

ETHNOPHARMACOLOGICAL RELEVANCE

The Timosaponin BⅡ (TBⅡ) is one of the main active components of the traditional Chinese medicine Anemarrhena asphodeloides, and it is a steroidal saponin with various pharmacological activities such as anti-oxidation, anti-inflammatory and anti-apoptosis. However, its role in acute ulcerative colitis remains unexplored thus far.

AIM OF THE STUDY

This study aims to investigate the protective effect of TBⅡ against dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and elucidate its underlying mechanisms.

METHODS

Wild-type (WT) and NLRP3 knockout (NLRP3-/-) mice were applied to evaluate the protective effect of TBⅡ in DSS-induced mice colitis. Pharmacological inhibition of NLRP3 or adenovirus-mediated NLRP3 overexpression in bone marrow-derived macrophages (BMDM) from WT mice and colonic epithelial HCoEpiC cells was used to assess the role of TBⅡ in LPS + ATP-induced cell model. RNA-seq, ELISA, western blots, immunofluorescence staining, and expression analysis by qPCR were performed to examine the alterations of colonic NLRP3 expression in DSS-induced colon tissues and LPS + ATP-induced cells, respectively.

RESULTS

In mice with DSS-induced ulcerative colitis, TBⅡ treatment attenuated clinical symptoms, repaired the intestinal mucosal barrier, reduced inflammatory infiltration, and alleviated colonic inflammation. RNA-seq analysis and protein expression levels demonstrated that TBⅡ could prominently inhibit NLRP3 signaling. TBⅡ-mediated NLRP3 inhibition was associated with alleviating intestinal permeability and inflammatory response via the blockage of communication between epithelial cells and macrophages, probably in an NLRP3 inhibition mechanism. However, pharmacological inhibition of NLRP3 by MCC950 or Ad-NLRP3 mediated NLRP3 overexpression significantly impaired the TBⅡ-mediated anti-inflammatory effect. Mechanistically, TBⅡ-mediated NLRP3 inhibition may be partly associated with the suppression of NF-κB, a master pro-inflammatory factor for transcriptional regulation of NLRP3 expression in the priming step. Moreover, co-treatment TBⅡ with NF-κB inhibitor BAY11-7082 partly impaired TBⅡ-mediated NLRP3 inhibition, and consequently affected the IL-1β mature and secretion. Importantly, TBⅡ-mediated amelioration was not further enhanced in NLPR3-/- mice.

CONCLUSION

TBⅡ exerted a prominent protective effect against DSS-induced colitis via regulation of alleviation of intestinal permeability and inflammatory response via the blockage of crosstalk between epithelial cells and macrophages in an NLRP3-mediated inhibitory mechanism. These beneficial effects could make TBⅡ a promising drug for relieving colitis.

Circadian rhythms in solid organ transplantation

Circadian rhythms are daily cycles in physiology that can affect medical interventions. This review considers how these rhythms may relate to solid organ transplantation. It begins by summarizing the mechanism for circadian rhythm generation known as the molecular clock, and basic research connecting the clock to biological activities germane to organ acceptance. Next follows a review of clinical evidence relating time of day to adverse transplantation outcomes. The concluding section discusses knowledge gaps and practical areas where applying circadian biology might improve transplantation success.

Melatonin restores hepatic lipid metabolic homeostasis disrupted by blue light at night in high-fat diet-fed mice

Artificial light at night (ALAN) is an emerging environmental pollutant that threatens public health. Recently, ALAN has been identified as a risk factor for obesity; however, the role of ALAN and its light wavelength in hepatic lipid metabolic homeostasis remains undetermined. We showed that chronic dim (~5 lx) ALAN (dLAN) exposure significantly promoted hepatic lipid accumulation in obese or diabetic mice, with the most severe effect of blue light and little effect of green or red light. These metabolic phenotypes were attributed to blue rather than green or red dLAN interfering with hepatic lipid metabolism, especially lipogenesis and lipolysis. Further studies found that blue dLAN disrupted hepatic lipogenesis and lipolysis processes by inhibiting hepatic REV-ERBs. Mechanistically, feeding behavior mediated the regulation of dLAN on hepatic REV-ERBs. In addition, different effects of light wavelengths at night on liver REV-ERBs depended on the activation of the corticosterone (CORT)/glucocorticoid receptor (GR) axis. Blue dLAN could activate the CORT/GR axis significantly while other wavelengths could not. Notably, we demonstrated that exogenous melatonin could effectively inhibit hepatic lipid accumulation and restore the hepatic GR/REV-ERBs axis disrupted by blue dLAN. These findings demonstrate that dLAN promotes hepatic lipid accumulation in mice via a short-wavelength-dependent manner, and exogenous melatonin is a potential therapeutic approach. This study strengthens the relationship between ALAN and hepatic lipid metabolism and provides insights into directing ambient light.

REV-ERBα negatively regulates NLRP6 transcription and reduces the severity of Salmonella infection in mice

Non-typhoidal Salmonella infection is among the most frequent foodborne diseases threatening human health worldwide. The host circadian clock orchestrates daily rhythms to adapt to environmental changes, including coordinating immune function in response to potential infections. However, the molecular mechanisms underlying the interplay between the circadian clock and the immune system in modulating infection processes are incompletely understood. Here, we demonstrate that NLRP6, a novel nucleotide-oligomerization domain (NOD)-like receptor (NLR) family member highly expressed in the intestine, is closely associated with the differential day-night response to Salmonella infection. The core clock component REV-ERBα negatively regulates NLRP6 transcription, leading to the rhythmic expression of NLRP6 and the secretion of IL-18 in intestinal epithelial cells, playing a crucial role in mediating the differential day-night response to Salmonella infection. Activating REV-ERBα with agonist SR9009 in wild-type mice attenuated the severity of infection by decreasing the NLRP6 level in intestinal epithelial cells. Our findings provide new insights into the association between the host circadian clock and the immune response to enteric infections by revealing the regulation of Salmonella infection via the inhibitory effect of REV-ERBα on NLRP6 transcription. Targeting REV-ERBα to modulate NLRP6 activation may be a potential therapeutic strategy for bacterial infections.

Circadian rhythm regulates the function of immune cells and participates in the development of tumors

Circadian rhythms are present in almost all cells and play a crucial role in regulating various biological processes. Maintaining a stable circadian rhythm is essential for overall health. Disruption of this rhythm can alter the expression of clock genes and cancer-related genes, and affect many metabolic pathways and factors, thereby affecting the function of the immune system and contributing to the occurrence and progression of tumors. This paper aims to elucidate the regulatory effects of BMAL1, clock and other clock genes on immune cells, and reveal the molecular mechanism of circadian rhythm's involvement in tumor and its microenvironment regulation. A deeper understanding of circadian rhythms has the potential to provide new strategies for the treatment of cancer and other immune-related diseases.

Rev-erbα attenuates refractory periapical periodontitis via M1 polarization: An in vitro and in vivo study

AIM

Rev-erbα has been reported to regulate the healing of inflammatory lesions through its effect on the immune system in a variety of inflammatory disease. Moreover, the balance of macrophages polarization plays a crucial role in immune response and inflammatory progression. However, in refractory periapical periodontitis (RAP), the role of Rev-erbα in inflammatory response and bone resorption by regulating macrophage polarization remains unclarified. The aims of the present study were to investigate the expression of Rev-erbα in experimental RAP and to explore the relationship between Rev-erbα and macrophage polarization through the application of its pharmacological agonist SR9009 into the in vivo and in vitro experiments.

METHODOLOGY

Enterococcus faecalis-induced RAP models were established in SD rats. Histological staining and micro-computed tomography scanning were used to evaluate osteoclastogenesis and alveolar bone resorption. The expression of Rev-erbα and macrophage polarization were detected in the periapical tissues from rats by immunofluorescence, flow cytometry, and western blots. Furthermore, immunohistochemical staining and enzyme-linked immunosorbent assay were performed to explore the relationship between Rev-erbα and inflammatory cytokines related to macrophage polarization.

RESULT

Compared to healthy periapical tissue, the expression of Rev-erbα was significantly down-regulated in macrophages from inflammatory periapical area, especially in Enterococcus faecalis-induced periapical lesions, with obvious type-1 macrophage (M1)-like dominance and the production of pro-inflammatory cytokines. In addition, Rev-erbα activation by SR9009 could induce type-2 macrophage (M2)-like polarization in periapical tissue and THP1 cell line, followed by increased secretion of anti-inflammatory cytokines IL-10 and TGF-β. Furthermore, intracanal application of SR9009 reduced the lesion size and promoted the repair of RAP by decreasing the number of osteoclasts and enhancing the formation of mineralized tissue in periapical inflammatory lesions.

CONCLUSIONS

Rev-erbα played an essential role in the pathogenesis of RAP through its effect on macrophage polarization. Targeting Rev-erbα might be a promising and prospective therapy method for the prevention and management of RAP.

YTHDF1-CLOCK axis contributes to pathogenesis of allergic airway inflammation through LLPS

N6-methyladenosine (m6A) modification has been implicated in many cell processes and diseases. YTHDF1, a translation-facilitating m6A reader, has not been previously shown to be related to allergic airway inflammation. Here, we report that YTHDF1 is highly expressed in allergic airway epithelial cells and asthmatic patients and that it influences proinflammatory responses. CLOCK, a subunit of the circadian clock pathway, is the direct target of YTHDF1. YTHDF1 augments CLOCK translation in an m6A-dependent manner. Allergens enhance the liquid-liquid phase separation (LLPS) of YTHDF1 and drive the formation of a complex comprising dimeric YTHDF1 and CLOCK mRNA, which is distributed to stress granules. Moreover, YTHDF1 strongly activates NLRP3 inflammasome production and interleukin-1β secretion leading to airway inflammatory responses, but these phenotypes are abolished by deleting CLOCK. These findings demonstrate that YTHDF1 is an important regulator of asthmatic airway inflammation, suggesting a potential therapeutic target for allergic airway inflammation.

Circadian Effects on Vascular Immunopathologies

Circadian rhythms exert a profound impact on most aspects of mammalian physiology, including the immune and cardiovascular systems. Leukocytes engage in time-of-day-dependent interactions with the vasculature, facilitating the emigration to and the immune surveillance of tissues. This review provides an overview of circadian control of immune-vascular interactions in both the steady state and cardiovascular diseases such as atherosclerosis and infarction. Circadian rhythms impact both the immune and vascular facets of these interactions, primarily through the regulation of chemoattractant and adhesion molecules on immune and endothelial cells. Misaligned light conditions disrupt this rhythm, generally exacerbating atherosclerosis and infarction. In cardiovascular diseases, distinct circadian clock genes, while functioning as part of an integrated circadian system, can have proinflammatory or anti-inflammatory effects on these immune-vascular interactions. Here, we discuss the mechanisms and relevance of circadian rhythms in vascular immunopathologies.