Luteolin suppresses TNF‑α‑induced inflammatory injury and senescence of nucleus pulposus cells via the Sirt6/NF‑κB pathway

Potential of SIRT6 modulators in targeting molecular pathways involved in cardiovascular diseases and their treatment-A comprehensive review

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity, accounting for major public health concerns worldwide. CVD poses an immense burden on the global healthcare system and economy. Ischemic heart disease, stroke, heart failure, atherosclerosis, and hypertension are the major diseases belonging to CVDs and ischemic heart diseases and stroke contribute to most CVD-induced deaths. Previously published review articles focused on the role of SIRT6 in CVDs but did not focus on the important role of SIRT6 in modulating the signaling pathways involved in CVDs and targeting them to treat CVDs. Thus, this review aims to identify and delineate the major signaling pathways that are involved in CVDs and whether SIRT6 can modulate those pathways to improve and treat CVDs. Alongside possible applications of small molecule modulators of SIRT6 in cardiovascular disease treatment have been comprehensively analyzed.

Extraction, detection, bioactivity, and product development of luteolin: A review

Luteolin is a kind of natural flavonoid, widely existing in a variety of plants, has been revealed to have a wide range of biological activities. In recent years, the research results of luteolin are abundant. Here we review the latest research results of luteolin in order to provide new ideas for further research and development of luteolin. In this paper, the focus of the search was published between 2010 and 2024 on the extraction and determination of luteolin, biological activities, and the development and application of luteolin products. A comprehensive search using the keyword "luteolin" was conducted in the PubMed, Web of Science and WIPO databases. Through the collection of related literature, this paper summarized a variety of extraction techniques of luteolin, including immersion extraction, solvent extraction, ultrasonic-assisted extraction, supercritical fluid extraction and so on. The determination methods include: thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), electrochemical method (ED) and so on. In addition, the biological activities of luteolin, including antioxidant, anti-inflammatory, anti-tumor, antibacterial, analgesic and so on, were described. And luteolin as the main component of the product is being gradually developed, and has been used in the field of food, medicine and cosmetics. This paper provides a reference for further study of luteolin.

The potential of flavonoids to mitigate cellular senescence in cardiovascular disease

Aging is one of the most significant factors affecting cardiovascular health, with cellular senescence being a central hallmark. Senescent cells (SCs) secrete a specific set of signaling molecules known as the senescence-associated secretory phenotype (SASP). The SASP has a remarkable impact on age-associated diseases, particularly cardiovascular diseases (CVD). Targeting SCs through anti-aging therapies represents a novel strategy to effectively retard senescence and attenuate disease progression. Accumulating evidence demonstrates that the flavonoids, widely presented in fruits and vegetables worldwide, can delay or treat CVD via selectively eliminating SCs (senolytics) and modulating SASPs (senomorphics). Nevertheless, only sporadic research has illustrated the application of flavonoids in targeting SCs for CVD, which requires further exploration. This review recapitulates the hallmarks and key molecular mechanisms involved in cellular senescence, then summarizes senescence of different types of cardiac cells and describes the mechanisms by which cellular senescence affects CVD development. The discussion culminates with the potential use of flavonoids via exerting their biological effects on cellular senescence to reduce CVD incidence. This summary will provide valuable insights for cardiovascular drug design, development and clinical applications leveraging flavonoids.

Targeting senescence induced by age or chemotherapy with a polyphenol-rich natural extract improves longevity and healthspan in mice

Accumulating senescent cells within tissues contribute to the progression of aging and age-related diseases. Botanical extracts, rich in phytoconstituents, present a useful resource for discovering therapies that could target senescence and thus improve healthspan. Here, we show that daily oral administration of a standardized extract of Salvia haenkei (Haenkenium (HK)) extended lifespan and healthspan of naturally aged mice. HK treatment inhibited age-induced inflammation, fibrosis and senescence markers across several tissues, as well as increased muscle strength and fur thickness compared with age-matched controls. We also found that HK treatment reduced acutely induced senescence by the chemotherapeutic agent doxorubicin, using p16LUC reporter mice. We profiled the constituent components of HK by mass spectrometry, and identified luteolin-the most concentrated flavonoid in HK-as a senomorphic compound. Mechanistically, by performing surface plasmon resonance and in situ proximity ligation assay, we found that luteolin disrupted the p16-CDK6 interaction. This work demonstrates that administration of HK promotes longevity in mice, possibly by modulating cellular senescence and by disrupting the p16-CDK6 interaction.

The role of sirtuins in intervertebral disc degeneration: Mechanisms and therapeutic potential

Intervertebral disc degeneration (IDD) is one of the main causes of low back pain, which affects the patients' quality of life and health and imposes a significant socioeconomic burden. Despite great efforts made by researchers to understand the pathogenesis of IDD, effective strategies for preventing and treating this disease remain very limited. Sirtuins are a highly conserved family of (NAD+)-dependent deacetylases in mammals that are involved in a variety of metabolic processes in vivo. In recent years, sirtuins have attracted much attention owing to their regulatory roles in IDD on physiological activities such as inflammation, apoptosis, autophagy, aging, oxidative stress, and mitochondrial function. At the same time, many studies have explored the therapeutic effects of sirtuins-targeting activators or micro-RNA in IDD. This review summarizes the molecular pathways of sirtuins involved in IDD, and summarizes the therapeutic role of activators or micro-RNA targeting Sirtuins in IDD, as well as the current limitations and challenges, with a view to provide possible solutions for the treatment of IDD.

Integrating network pharmacology, experimental validation and molecular docking to reveal the alleviation of Yinhuang granule on idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by the abnormal proliferation of fibroblast and excessive deposition of extracellular matrix (ECM), accompanied by inflammation and ultimately respiratory failure. Yinhuang granule (YHG), with clinical properties of clearing heat, detoxifying and anti-inflammation, is commonly used to heal upper respiratory diseases in China for decades.

PURPOSE

To explore the improvement of YHG on bleomycin (BLM)-induced IPF in mice and its possible engaged mechanism.

METHODS

The mortality rate was recorded, lung function was determined and hematoxylin-eosin (H&E) staining was carried out to explore the alleviation of YHG on BLM-caused IPF in mice. Hydroxyproline, collagen I and collagen III contents were detected, and Sirius red and Masson staining were conducted to evaluate YHG's alleviation on lung fibrosis. The underlying mechanism was predicted by network pharmacology, and confirmed by Real-time polymerase chain reaction (RT-PCR), Western-blot (WB) and enzyme linked immunosorbent assay (ELISA). The binding affinity between related key proteins and active compounds in YHG was calculated by using molecular docking, and further validated by cellular thermal shift assay (CESTA).

RESULTS

YHG (400, 800 mg/kg) weakened lung damage and pulmonary fibrosis in mice induced by BLM. Network pharmacology and experimental validation displayed that inflammation and angiogenesis participated in the YHG-provided improvement on IPF, and key involved molecules included tumor necrosis factor-α (TNFα), vascular endothelial growth factor-A (VEGFA), interleukine-6 (IL-6), etc. The data of molecular docking presented that some main active compounds from YHG had a high binding affinity with TNFR1 or VEGFR2, and some of them were further validated by CESTA.

CONCLUSION

YHG effectively improved the BLM-induced IPF in mice via reducing inflammation and angiogenesis.

M6A methylation-regulated autophagy may be a new therapeutic target for intervertebral disc degeneration

Degeneration of intervertebral discs is considered one of the most important causes of low back pain and disability. The intervertebral disc (IVD) is characterized by its susceptibility to various stressors that accelerate the senescence and apoptosis of nucleus pulposus cells, resulting in the loss of these cells and dysfunction of the intervertebral disc. Therefore, how to reduce the loss of nucleus pulposus cells under stress environment is the main problem in treating intervertebral disc degeneration. Autophagy is a kind of programmed cell death, which can provide energy by recycling substances in cells. It is considered to be an effective method to reduce the senescence and apoptosis of nucleus pulposus cells under stress. However, further research is needed on the mechanisms by which autophagy of nucleus pulposus cells is regulated under stress environments. M6A methylation, as the most extensive RNA modification in eukaryotic cells, participates in various cellular biological functions and is believed to be related to the regulation of autophagy under stress environments, may play a significant role in nucleus pulposus responding to stress. This article first summarizes the effects of various stressors on the death and autophagy of nucleus pulposus cells. Then, it summarizes the regulatory mechanism of m6A methylation on autophagy-related genes under stress and the role of these autophagy genes in nucleus pulposus cells. Finally, it proposes that the methylation modification of autophagy-related genes regulated by m6A may become a new treatment approach for intervertebral disc degeneration, providing new insights and ideas for the clinical treatment of intervertebral disc degeneration.

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

Sirtuins as Players in the Signal Transduction of Citrus Flavonoids

Sirtuins (SIRTs) belong to the family of nicotine adenine dinucleotide (NAD+)-dependent class III histone deacetylases, which come into play in the regulation of epigenetic processes through the deacetylation of histones and other substrates. The human genome encodes for seven homologs (SIRT1-7), which are localized into the nucleus, cytoplasm, and mitochondria, with different enzymatic activities and regulatory mechanisms. Indeed, SIRTs are involved in different physio-pathological processes responsible for the onset of several human illnesses, such as cardiovascular and neurodegenerative diseases, obesity and diabetes, age-related disorders, and cancer. Nowadays, it is well-known that Citrus fruits, typical of the Mediterranean diet, are an important source of bioactive compounds, such as polyphenols. Among these, flavonoids are recognized as potential agents endowed with a wide range of beneficial properties, including antioxidant, anti-inflammatory, hypolipidemic, and antitumoral ones. On these bases, we offer a comprehensive overview on biological effects exerted by Citrus flavonoids via targeting SIRTs, which acted as modulator of several signaling pathways. According to the reported studies, Citrus flavonoids appear to be promising SIRT modulators in many different pathologies, a role which might be potentially evaluated in future therapies, along with encouraging the study of those SIRT members which still lack proper evidence on their support.

Luteolin induces ferroptosis in prostate cancer cells by promoting TFEB nuclear translocation and increasing ferritinophagy

BACKGROUND

As the second most common cancer in men and the leading cause of cancer-related death, prostate cancer (PCa) could potentially be treated by inducing ferroptosis. In this study, we aimed to investigate whether luteolin could induce ferroptosis in PCa cells through the transcription Factor EB (TFEB).

METHODS

Different concentrations of luteolin were applied to treat normal prostate epithelial cells RWPE-1 and PCa cell lines DU145, PC-3, VCaP, and LNcaP. Ferrostatin-1 (Fer-1), Necrostain-1 (Nec-1), 3-methyladenine (3-MA), chloroquine (CQ), and the apoptosis inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (Z-VAD-FMK) were added to treat DU145 and PC-3 cells. Additionally, we knocked down TFEB and performed in vitro cell experiments. Finally, tumor-forming experiments in nude mice were conducted to verify luteolin mechanism in PCa after knocking down TFEB.

RESULTS

There was no significant difference in RWPE-1 at 12, 24, and 48 h after treatment with 60 μM luteolin. However, a significant difference was observed between DU145 and PC-3 cells. Luteolin exhibited a promoting effect on PCa cell death. After treatment with luteolin, cell viability, and Ki67 expression were decreased, and AnV-PI-positive dead cells were increased. Fer-1, Nec-1, 3-MA, and Z-VAD-FMK reversed luteolin effects on DU145 and PC-3 cell viability, proliferation, and AnV-PI-positive dead cells. Among them, Fer-1 and 3-MA were more effective. Luteolin-induced increased autophagy and ferroptosis in DU145 and PC-3 cells. Moreover, luteolin promoted ferroptosis by inducing increased autophagy in DU145 and PC-3 cells. However, knockdown of TFEB reversed the ability of luteolin to induce lysosome degradation of ferritin. In addition, luteolin promoted PCa ferroptosis by inducing ferritinophagy in vivo.

CONCLUSIONS

Luteolin-induced ferroptosis in PCa cells by promoting TFEB nuclear translocation and increasing ferritinophagy.

Epigenetic modifications of inflammation in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a common cause of joint-related chronic disability in elderly individuals worldwide. It seriously impacts the quality of life and inflicts a substantial social and economic burden. The pathological mechanisms underlying IDD have not been fully revealed, leading to less satisfactory clinical treatment outcomes. More studies are urgently needed to reveal its precise pathological mechanisms. Numerous studies have revealed that inflammation is closely related to various pathological processes of IDD, including the continuous loss of extracellular matrix, cell apoptosis, and senescence, indicating the important role of inflammation in the pathological mechanism of IDD. Epigenetic modifications affect the functions and characteristics of genes mainly through DNA methylation, histone modification, non-coding RNA regulation, and other mechanisms, thus having a major effect on the survival state of the body. Recently, the role of epigenetic modifications in inflammation during IDD has been attracting research interest. In this review, we summarize the roles of different types of epigenetic modifications in inflammation during IDD in recent years, to improve our understanding of the etiology of IDD and to transform basic research strategy into a clinically effective treatment for joint-related chronic disability in elderly individuals.

A Network Pharmacology Method Combined with Molecular Docking Verification to Explore the Therapeutic Mechanisms Underlying Simiao Pill Herbal Medicine against Hyperuricemia

Objective

Hyperuricemia (HUA) is a common metabolic disease caused by disordered purine metabolism. We aim to reveal the mechanisms underlying the anti-HUA function of Simiao pill and provide therapeutic targets.

Methods

Simiao pill-related targets were obtained using Herbal Ingredients' Targets (HIT), Traditional Chinese Medicine Systems Pharmacology (TCMSP), and Traditional Chinese Medicine Integrated Database (TCMID). HUA-associated targets were retrieved from GeneCards, DisGeNET, and Therapeutic Targets Database (TTD). Protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, ggraph and igraph R packages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using ClusterProfiler. The top 10 core targets were identified through cytoHubba. Molecular docking was conducted using PyMOL and AutoDock high-performance liquid chromatograph (HPLC) analysis was performed to identify effective compounds of Simiao pill.

Results

Simiao pill-HUA target network contained 80 targets. The key targets were mainly involved in inflammatory responses. Insulin (INS), tumor necrosis factor (TNF), interleukin-6 (IL6), interleukin 1 beta (IL1B), vascular endothelial growth factor A (VEGFA), leptin (LEP), signal transducer and activator of transcription 3 (STAT3), C-C motif chemokine ligand 2 (CCL2), interleukin-10 (IL10), and toll like receptor 4 (TLR4) were the top 10 targets in the PPI network. GO analysis demonstrated the main implication of the targets in molecular responses, production, and metabolism. KEGG analysis revealed that Simiao pill might mitigate HUA through advanced glycation end-product- (AGE-) receptor for AGE- (RAGE-) and hypoxia-inducible factor-1- (HIF-1-) associated pathways. IL1B, IL6, IL10, TLR4, and TNF were finally determined as the promising targets of Simiao pill treating HUA. Through molecular docking and HPLC analysis, luteolin, quercetin, rutaecarpine, baicalin, and atractylenolide I were the main active compounds.

Conclusions

Simiao pill can mitigate HUA by restraining inflammation, mediating AGE-RAGE- and HIF-1-related pathways, and targeting IL1B, IL6, IL10, TLR4, and TNF.

In Vitro Effect of Flavonoids on Basophils Degranulation and Intestinal Epithelial Barrier Damage Induced by ω-5 Gliadin-Derived Peptide

Flavonoids have antioxidant, anti-inflammatory and immunomodulatory properties, and may alleviate food allergic reactions and intestinal inflammation induced by ω-5 gliadin, a main allergen of wheat food allergy in children. In this study, a human basophil KU812 cell degranulation model and a Caco-2 monolayer cell model were constructed in vitro to evaluate the effects of four flavonoids on the allergenicity of ω-5 gliadin peptides and ω-5 gliadin peptide-induced barrier damage in Caco-2 intestinal epithelial monolayers. The results show that baicalein, luteolin, isorhamnetin and naringenin can significantly inhibit the degranulation of KU812 cells stimulated by ω-5 gliadin-derived peptide P4 and the release of IL-6 and TNF-α. In addition, the four flavonoids significantly inhibited the ω-5 gliadin-derived peptide P4 to induce the release of IL-6, IL-8 in Caco-2 cells, inhibited the release of zonulin, and significantly increase the expression of tight junction proteins Occludin and ZO-1 in the Caco-2 cell monolayer. In conclusion, baicalein, luteolin, isorhamnetin and naringenin inhibit degranulation stimulated by wheat allergen and enhance intestinal barrier functions, which supports the potential pharmaceutical application of the four flavonoids treatment for wheat food allergy.

Recent Updates on Source, Biosynthesis, and Therapeutic Potential of Natural Flavonoid Luteolin: A Review

Nature gives immense resources that are beneficial to humankind. The natural compounds present in plants provide primary nutritional values to our diet. Apart from food, plants also provide chemical compounds with therapeutic values. The importance of these plant secondary metabolites is increasing due to more studies revealing their beneficial properties in treating and managing various diseases and their symptoms. Among them, flavonoids are crucial secondary metabolite compounds present in most plants. Of the reported 8000 flavonoid compounds, luteolin is an essential dietary compound. This review discusses the source of the essential flavonoid luteolin in various plants and its biosynthesis. Furthermore, the potential health benefits of luteolins such as anti-cancer, anti-microbial, anti-inflammatory, antioxidant, and anti-diabetic effects and their mechanisms are discussed in detail. The activity of luteolin and its derivatives are diverse, as they help to prevent and control many diseases and their life-threatening effects. This review will enhance the knowledge and recent findings regarding luteolin and its therapeutic effects, which are certainly useful in potentially utilizing this natural metabolite.