Luteoloside Exerts Analgesic Effect in a Complete Freund's Adjuvant-Induced Inflammatory Model via Inhibiting Interleukin-1β Expression and Macrophage/Microglia Activation

Luteoloside mitigates premature age-related macular degeneration by suppressing p53-p21-Rb1 axis: Insights from transcriptomic analysis, serum metabolomics and gut microbiota analysis

Transcriptomics of dry age-related macular degeneration (AMD) patients with premature aging revealed the upregulated pathways involved in glycerolipid metabolism, tyrosine metabolism, and pentose and glucuronate interconversion. To investigate natural strategies for modulating these implicated pathways, we examined the impact and underlying mechanism of luteoloside on premature AMD using a stress-induced premature senescence (SIPS)-associated AMD animal model in middle-aged mice that mimicked the dysregulated pathways observed in dry AMD patients with premature aging. Luteoloside supplementation resulted in a significant reduction in serum levels of the pro-inflammatory cytokine IL-1β and lipofuscin, along with increased serum activity of the antioxidant enzyme superoxide dismutase (SOD) and elevated levels of pigment epithelium-derived factor (PEDF), and preserved retinal thickness and structure in AMD mice. Furthermore, luteoloside supplementation effectively reversed the abnormal serum levels of metabolites, particularly by reducing harmful lysophosphatidylcholine (LysoPC) and increasing beneficial 4-guanidinobutanoic acid. In addition to its impact on metabolites, luteoloside modulated the composition of gut microbiota, promoting the enrichment of beneficial bacterial populations, including Lactobacillus, while reducing the abundance of harmful bacterial populations, including Bacteroides. Overall, our findings highlight the potential of luteoloside supplementation in regulating the dysregulated intestinal microbiota and metabolites in premature AMD, thereby reducing ocular levels of senescence-associated secretory phenotype (SASP) factors through the suppression of the p53-p21-retinoblastoma protein 1 (Rb1) axis.

Function and inhibition of P38 MAP kinase signaling: Targeting multiple inflammation diseases

Inflammation is a natural host defense mechanism that protects the body from pathogenic microorganisms. A growing body of research suggests that inflammation is a key factor in triggering other diseases (lung injury, rheumatoid arthritis, etc.). However, there is no consensus on the complex mechanism of inflammatory response, which may include enzyme activation, mediator release, and tissue repair. In recent years, p38 MAPK, a member of the MAPKs family, has attracted much attention as a central target for the treatment of inflammatory diseases. However, many p38 MAPK inhibitors attempting to obtain marketing approval have failed at the clinical trial stage due to selectivity and/or toxicity issues. In this paper, we discuss the mechanism of p38 MAPK in regulating inflammatory response and its key role in major inflammatory diseases and summarize the synthetic or natural products targeting p38 MAPK to improve the inflammatory response in the last five years, which will provide ideas for the development of novel clinical anti-inflammatory drugs based on p38 MAPK inhibitors.

Luteolin-7-O-glucoside promotes macrophage release of IFN-β by maintaining mitochondrial function and corrects the disorder of glucose metabolism during RSV infection

Respiratory syncytial virus (RSV) pneumonia is the main cause of acute bronchiolitis in infants. Luteolin-7-O-glucoside (LUT-7G) is a natural flavonoid, which exists in a variety of plants and has the potential to treat viral pneumonia. We established RSV pneumonia mouse models and RSV-infected cell models. Clodronate liposomes were used to deplete macrophages. We used HE staining and immunohistochemistry to determine inflammatory damage and virus replication. We detected the expression levels of inflammatory factors and IFN-β through qPCR and ELISA. JC-1 kit was used for detecting the cell mitochondrial Membrane potential (MMP). ROS, SOD, and MDA kits were used for detecting intracellular oxidative stress damage. Metabolites of TCA in lung tissue and serum of mice were detected by GC-MS. Pharmacodynamic studies have shown that intervention with LUT-7G can alleviate lung tissue damage caused by RSV infection, inhibit RSV replication, and downregulate TNF-α, IL-1β, and IL-6 mRNA expression. LUT-7G upregulated the IFN-β content and the expression of IFN-β, ISG15, and OAS1 mRNA. In vitro, LUT-7G inhibited RSV-induced cell death, reversed the RSV-induced decrease of MMP and decreased intracellular oxidative stress. Target metabonomics showed that RSV infection upregulated the levels of glycolysis and TCA metabolites in lung tissue and serum, while LUT-7G could improve the disorder of glucose metabolism. The results indicate that LUT-7G can promote the release of IFN-β in the lung, alleviate inflammatory damage, and inhibit RSV replication during RSV infection. These effects may be achieved by protecting the mitochondrial function of alveolar macrophages and correcting the disorder of glucose metabolism.

Similarities and differences between Ziqin and Kuqin in anti-inflammatory, analgesic, and antioxidant activities and their core chemical composition based on the zebrafish model and spectrum-effect relationship

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria baicalensis (SB) is a traditional Chinese medicine (TCM). In the clinical application of TCM, SB has been divided into two specifications (Ziqin and Kuqin) for a long time. At present, the Chinese Pharmacopoeia Commission no longer distinguishes between the two. However, the two specifications of medicinal materials and pieces are still in circulation in the market.

AIM OF THE STUDY

This work aimed at investigating the similarities and differences between Ziqin and Kuqin in anti-inflammatory, analgesic, and antioxidant activities and their material basis. It will provide a new angle for relevant regulations to formulate the specifications and standards of SB.

MATERIALS AND METHODS

Here we investigated the similarities and differences between Ziqin and Kuqin in anti-inflammatory, analgesic, and antioxidant activities related to four zebrafish models and three chemical tests. The chemical fingerprints of SB (Ziqin and Kuqin) were profiled by HPLC. Meanwhile, UHPLC-Q-TOF/MS was used to identify the chemical constituents of Ziqin and Kuqin. The main effect-related compounds of SB, Ziqin, and Kuqin were screened out by spectrum-effect relationship. Finally, six monomeric compounds were validated experimentally using the zebrafish inflammation model induced by CuSO₄.

RESULTS

Both Ziqin and Kuqin had significant anti-inflammatory, analgesic, and antioxidant activities. Kuqin had better anti-inflammatory and analgesic activities, while Ziqin had better antioxidant activity. HPLC fingerprint and UHPLC-Q-TOF/MS evaluation showed that the chemical composition types and main components of Ziqin and Kuqin were basically the same, while the contents and proportions of chemical components in Ziqin and Kuqin were different. By spectrum-effect relationship, compounds X1, X2 (luteoloside), X3, X4 (baicalin), X6 (wogonoside), X7 (baicalein), X8 (wogonin), and X9 (oroxylin A) were the same active chemical constituents of Ziqin and Kuqin. The core components of anti-inflammatory and analgesia activities in Kuqin were compounds X1, X2, X3, X5, X6, X7, X8, and X9. The antioxidant core active components of Ziqin were compounds X2, X3, X4, X6, X7, and X9. Among them, luteoloside, baicalin, wogonoside, baicalein, wogonin, and oroxylin A were validated successfully with good anti-inflammatory effects.

CONCLUSIONS

This study revealed that Ziqin and kuqin have high similarity in chemical composition, but their proportions and active core components are different. This may be one of the main reasons why they have the same activity but different activity trends. These findings will help to improve the understanding of the different clinical applications of Ziqin and Kuqin, and provide a reference for the formulation of quality standards and their further research.

Regulation of SIRT1-TLR2/TLR4 pathway in cell communication from macrophages to hepatic stellate cells contribute to alleviates hepatic fibrosis by Luteoloside

Regulating macrophage-hepatic stellate cells (HSCs) crosstalk through SIRT1-TLR2/TLR4 has contributed to the essence of new pharmacologic strategies to improve hepatic fibrosis. We investigated how Luteoloside (LUT), one of the flavonoid monomers isolated from Eclipta prostrata (L.) L., modulates macrophage-HSCs crosstalk during hepatic fibrosis. HSC-T6 or rat peritoneal macrophages were activated by TGF-β or LPS/ATP, and then treated with LUT or Sirtinol (SIRT1 inhibitor) for 6 h. Further, HSCs were cultured with the conditioned medium from the LPS/ATP activated peritoneal macrophages. In HSC-T6 or peritoneal macrophages, LUT could decrease the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. LUT also significantly increased the expressions of SIRT1 and ERRα. And LUT significantly suppressed the releases of pro-inflammatory cytokines, including NLRP3, ASC, caspase-1, IL-1β, and regulated signaling TLR2/TLR4-MyD88 activation. The expressions of TLR2, TLR4, NLRP3, caspase-1, IL-1β, α-SMA were increased and the expression of ERRα was decreased by Sirtinol, indicated that LUT might mediate SIRT1 to regulate TLR4 expression and further alleviate inflammation and fibrosis. LUT could regulate SIRT1-mediated TLR4 and ECM in HSCs was reduced, when HSCs were cultured with conditioned medium. Hence, LUT could decrease the expressions of fibrosis markers, reduce the releases of inflammatory cytokines in activated HSCs or macrophages. In conclusion, LUT might be a promising candidate that regulating SIRT1-TLR2/TLR4 signaling in macrophages interacting with HSCs during hepatic fibrosis.

In silico identification of natural antiviral compounds as a potential inhibitor of chikungunya virus non-structural protein 3 macrodomain

Chikungunya Virus (CHIKV) is having a major impact on humans with potentially life-threatening and debilitating arthritis. The lack of a specific antiviral drug against the CHIKV disease has created an alarming situation to identify or develop potent chemical molecules for its remedial measures. Antiviral therapies for viral diseases are generally expensive and have adverse side effects. Plant-based antiviral natural compounds are the most suitable and best alternative of current antiviral drugs because of less toxicity. In the present study, non-structural protein 3 macrodomain (nsP3^MD) of the CHIKV that is essential for virus replication has been selected for anti CHIKV drug target. The compounds were identified using molecular docking, virtual screening and further evaluated by molecular dynamics (MD) simulation studies. The binding mechanism of each compound was analyzed considering the stability and energetic parameter. We have found six plant-based natural antiviral compounds Baicalin, Rutaecarpine, Amentoflavone, Apigetrin, Luteoloside, and Baloxavir as strong inhibitors of nsP3^MD of CHIKV. ADMET prediction and target analysis of the selected compounds showed drug likeliness of these compounds. MD simulation studies indicated energetically favorable complex formation between nsP3^MD and the selected antiviral compounds. Furthermore, the structural effects on these substitutions were analyzed using the principles of each trajectory, which validated the interaction studies. Our analysis suggests a very high probability of these compounds to inhibit nsP3^MD of CHIKV and could be evaluated for Chikungunya fever drug development. Communicated by Ramaswamy H. Sarma.

Targeting Oxidative Stress and Inflammation in Intervertebral Disc Degeneration: Therapeutic Perspectives of Phytochemicals

Low back pain is a major cause of disability worldwide that declines the quality of life; it poses a substantial economic burden for the patient and society. Intervertebral disc (IVD) degeneration (IDD) is the main cause of low back pain, and it is also the pathological basis of several spinal degenerative diseases, such as intervertebral disc herniation and spinal stenosis. The current clinical drug treatment of IDD focuses on the symptoms and not their pathogenesis, which results in frequent recurrence and gradual aggravation. Moreover, the side effects associated with the long-term use of these drugs further limit their use. The pathological mechanism of IDD is complex, and oxidative stress and inflammation play an important role in promoting IDD. They induce the destruction of the extracellular matrix in IVD and reduce the number of living cells and functional cells, thereby destroying the function of IVD and promoting the occurrence and development of IDD. Phytochemicals from fruits, vegetables, grains, and other herbs play a protective role in the treatment of IDD as they have anti-inflammatory and antioxidant properties. This article reviews the protective effects of phytochemicals on IDD and their regulatory effects on different molecular pathways related to the pathogenesis of IDD. Moreover, the therapeutic limitations and future prospects of IDD treatment have also been reviewed. Phytochemicals are promising candidates for further development and research on IDD treatment.

JAK2/STAT3 pathway regulates microglia polarization involved in hippocampal inflammatory damage due to acute paraquat exposure

OBJECTIVE

To explore the effects of acute paraquat (PQ) exposure on the phenotypic polarization of hippocampal microglia and its mechanism.

METHODS

An acute PQ exposure rat model was established. Male SD rats were exposed to 0, 5, 25, and 50 mg/kg PQ, and brain hippocampal tissue was collected after 1, 3, and 7 days of exposure, respectively. Hippocampal pathological changes were examined by H&E staining, and immunohistochemistry (IHC) was used to detect changes in the number of Iba-1-positive cells, the average number of endpoints, and the average process length. The protein expression of Iba-1 was detected by western blotting. BV-2 microglia were treated with 0, 0.01, 0.025, 0.05, or 0.1 μmol/L PQ for 24 h. ELISA and western blotting assays were performed to detect the expression of TNF-α and IL-1β in vivo and in vitro. The M1 microglia marker iNOS, the M2 microglia marker Arg-1, and the p-JAK2 and p-STAT3 protein were detected by western blotting. JAK2/STAT3 pathway activation role in regulating microglia phenotypic polarization was further validated in vivo and in vitro by JAK2-specific inhibitor AG490 administration.

RESULTS

After acute PQ exposure, hippocampal neurons showed pathological changes such as loose arrangement and nuclear pyknosis, the number of Iba-1 positive cells and the expression of Iba-1 protein increased, and the average number of endpoints and average process length of microglia decreased. Histological examination revealed that compared with the control group, in the 50 mg/kg PQ group on the 3rd and 7th day, the expression of TNF-α, IL-1β, and iNOS significantly increased, while that of Arg-1 significantly decreased. p-JAK2 and p-STAT3 expression significantly increased in the 50 mg/kg PQ group on the 1st, 3rd, and 7th day. In vitro, compared with the control group, the expression of TNF-α, IL-1β, iNOS, p-JAK2, and p-STAT3 significantly increased, while Arg-1 expression was significantly reduced in the 0.025, 0.05, and 0.1 μmol/L PQ groups. After AG490 administration, the expression levels of p-JAK2, p-STAT3, iNOS, TNF-α, and IL-1β in the AG490 +PQ group were significantly inhibited in vivo and in vitro compared with the PQ-only group. On the contrary, Arg-1 expression was significantly increased.

CONCLUSION

Our results suggest that acute PQ exposure may induce M1-type polarization of hippocampal microglia by activating the JAK2/STAT3 pathway, which in turn releases pro-inflammatory factors such as TNF-α and IL-1β, leading to hippocampal inflammatory damage.

A Novel Progress: Glial Cells and Inflammatory Pain

Inflammatory pain is the perception of noxious stimuli that occurs during inflammation or an immune response. Glial cells are widespread in the central and peripheral nervous systems, supporting and guiding the migration of neurons, participating in the immune response, forming the myelin sheath and blood-brain barrier, and maintaining the concentration of potassium ions outside nerve cells. Recent studies have shown that glial cells have a significant connection with the production and development of inflammatory pain. This article reviews the relationship, mechanisms, therapeutic targets between five types of glial cells and inflammatory pain, and the medicine composition that can effectively inhibit inflammatory pain. It expands the study on the mechanism of glial cells regulating pain and provides new ideas for the therapy of inflammatory pain.

Natural Products of Pharmacology and Mechanisms in Nucleus Pulposus Cells and Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is one of the main causes of low back pain (LBP), which severely reduces the quality of life and imposes a heavy financial burden on the families of affected individuals. Current research suggests that IDD is a complex cell-mediated process. Inflammation, oxidative stress, mitochondrial dysfunction, abnormal mechanical load, telomere shortening, DNA damage, and nutrient deprivation contribute to intervertebral disc cell senescence and changes in matrix metabolism, ultimately causing IDD. Natural products are widespread, structurally diverse, afford unique advantages, and exhibit great potential in terms of IDD treatment. In recent years, increasing numbers of natural ingredients have been shown to inhibit the degeneration of nucleus pulposus cells through various modes of action. Here, we review the pharmacological effects of natural products on nucleus pulposus cells and the mechanisms involved. An improved understanding of how natural products target signalling pathways will aid the development of anti-IDD drugs. This review focuses on potential IDD drugs.

Transcriptome-wide characterization of the WRKY family genes in Lonicera macranthoides and the role of LmWRKY16 in plant senescence

BACKGROUND

Lonicera macranthoides is an important woody plant with high medicinal values widely cultivated in southern China. WRKY, one of the largest transcription factor families, participates in plant development, senescence, and stress responses. However, a comprehensive study of the WRKY family in L. macranthoides hasn't been reported previously.

OBJECTIVE

To establish an extensive overview of the WRKY family in L. macranthoides and identify senescence-responsive members of LmWRKYs.

METHODS

RNA-Seq and phylogenetic analysis were employed to identify the LmWRKYs and their evolutionary relationships. Quantitative real-time (qRT-PCR) and transgenic technology was utilized to investigate the roles of LmWRKYs in response to developmental-, cold-, and ethylene-induced senescence.

RESULTS

A total of 61 LmWRKY genes with a highly conserved motif WRKYGQK were identified. Phylogenetic analysis of LmWRKYs together with their orthologs from Arabidopsis classified them into three groups, with the number of 15, 39, and 7, respectively. 17 LmWRKYs were identified to be differentially expressed between young and aging leaves by RNA-Seq. Further qRT-PCR analysis showed 15 and 5 LmWRKY genes were significantly induced responding to tissue senescence in leaves and stems, respectively. What's more, five LmWRKYs, including LmWRKY4, LmWRKY5, LmWRKY6, LmWRKY11, and LmWRKY16 were dramatically upregulated under cold and ethylene treatment in both leaves and stems, indicating their involvements commonly in developmental- and stress-induced senescence. In addition, function analysis revealed LmWRKY16, a homolog of AtWRKY75, can accelerate plant senescence, as evidenced by leaf yellowing during reproductive growth in LmWRKY16-overexpressing tobaccos.

CONCLUSION

The results lay the foundation for molecular characterization of LmWRKYs in plant senescence.