Periodontitis-level butyrate-induced ferroptosis in periodontal ligament fibroblasts by activation of ferritinophagy

Metabolism-epigenetic interaction-based bone and dental regeneration: From impacts and mechanisms to treatment potential

Metabolic pathways exhibit fluctuating activities during bone and dental loss and defects, suggesting a regulated metabolic plasticity. Skeletal remodeling is an energy-demanding process related to altered metabolic activities. These metabolic changes are frequently associated with epigenetic modifications, including variations in the expression or activity of enzymes modified through epigenetic mechanisms, which directly or indirectly impact cellular metabolism. Metabolic reprogramming driven by bone and dental conditions alters the epigenetic landscape by modulating the activities of DNA and histone modification enzymes at the metabolite level. Epigenetic mechanisms modulate the expression of metabolic genes, consequently influencing the metabolome. The interplay between epigenetics and metabolomics is crucial in maintaining bone and dental homeostasis by preserving cell proliferation and pluripotency. This review, therefore, aims to examine the effects of metabolic reprogramming in bone and dental-related cells on the regulation of epigenetic modifications, particularly acetylation, methylation, and lactylation. We also discuss the effects of chromatin-modifying enzymes on metabolism and the potential therapeutic benefits of dietary compounds as epigenetic modulators. In this review, we highlight the inconsistencies in current research findings and suggest potential approaches to translate fundamental insights into clinical treatments for bone and tooth diseases.

Role of periodontal ligament fibroblasts in periodontitis: pathological mechanisms and therapeutic potential

Periodontal ligament fibroblasts (PDLFs) play a crucial role in the etiology of periodontitis and periodontal tissue regeneration. In healthy periodontal tissues, PDLFs maintain the homeostasis of periodontal soft and hard tissues as well as the local immune microenvironment. PDLFs also have the potential for multidirectional transdifferentiation and are involved in periodontal tissue regeneration. On the other hand, PDLFs can become dysfunctional and acquire an inflammatory phenotype to secret various inflammatory cytokines when affected by pathological factors. These cytokines further trigger immune and inflammatory events, and lead to destruction of periodontal soft and hard tissues as well as damage to the regenerative potential of PDLFs. This review summarizes the physiological functions of PDLFs. Meanwhile, this review also highlights recent insights into the pathological mechanisms driving the development of periodontitis through dysfunctional PDLFs and the negative impact on periodontal tissue regeneration. Additionally, this paper summarizes strategies for targeting PDLFs to treat periodontitis, involving blocking multiple stages of the inflammatory response induced by PDLFs and promoting the multidirectional transdifferentiation of PDLFs. Future research directions are proposed to address important questions that have not yet been answered in this field. This article provides a reference for understanding the important role of PDLFs in the pathological mechanisms of periodontitis and for developing new strategies for targeting PDLFs in periodontitis treatment.

Detection of molecular markers of ferroptosis in human Alzheimer's disease brains

BACKGROUND

We have previously shown that droplet degeneration (DD) signifies the beginning of neuritic plaque formation during Alzheimer's disease (AD) pathogenesis. As microglia associated with neuritic plaques exhibited strong ferritin expression and Perl's iron staining showed iron in microglia, droplet spheres and neuritic plaque cores, we hypothesized that DD is a form of ferroptosis.

OBJECTIVE

Detection of molecular markers of ferroptosis in AD brains.

METHODS

Immunohistochemical detection of transferrin receptor (TfR) and ferritin as ferroptosis markers in prefrontal cortex of AD brains, investigation of spatial correlation of these with histopathological hallmarks of AD, visualization of ferroptotic marker genes by in situ hybridization, comparison of expression of ferroptosis genes with snRNAseq analyses and comparison of TfR and ferritin expression in different neurofibrillary tangle (NFT) stages.

RESULTS

TfR was found on neurons that appeared to be degenerating and exhibited typical features of droplet degeneration. Co-localization with hyperphosphorylated tau (p-tau) was a rare event. TfR-positive neurons increased with higher NFT stages as did ferritin expression in microglia. mRNA of genes linked to ferroptosis was detected in pretangles and p-tau negative neurons, less in DD. snRNAseq analyses support a link between AD, ferroptosis and TfR as a ferroptosis marker.

CONCLUSIONS

Increased expression of TfR and ferritin in high NFT stages, demonstration of ferroptotic marker genes in Alzheimer's lesions, as well as snRNAseq analyses strengthen our hypothesis that DD represents ferroptosis. Because of the morphological similarity between TfR-positive structures and DD, TfR might be an early ferroptosis marker expressed transiently during AD pathogenesis.

Single-cell analysis reveals a unique microenvironment in peri-implantitis

AIM

This study aimed to reveal the unique microenvironment of peri-implantitis through single-cell analysis.

MATERIALS AND METHODS

Herein, we performed single-cell RNA sequencing (scRNA-seq) of biopsies from patients with peri-implantitis (PI) and compared the results with healthy individuals (H) and patients with periodontitis (PD).

RESULTS

Decreased numbers of stromal cells and increased immune cells were found in the PI group, which implies a severe inflammatory infiltration. The fibroblasts were found to be heterogeneous and the specific pro-inflammatory CXCL13+ sub-cluster was more represented in the PI group, in contrast to the PD and H groups. Furthermore, more neutrophil infiltration was detected in the PI group than in the PD group, and cell-cell communication and ligand-receptor pairs revealed most neutrophils were recruited by CXCL13+ fibroblasts through CXCL8/CXCL6-CXCR2/CXCR1. Notably, our study demonstrated that the unique microenvironment of the PI group promoted the differentiation of monocyte/macrophage lineage cells into osteoclasts, which might explain the faster and more severe bone resorption in the progression of PI than PD.

CONCLUSIONS

Collectively, this study suggests a unique immune microenvironment of PI, which may explain the differences between PI and PD in the clinic. These outcomes will aid in finding new specific and effective treatments for PI.

[Research progress on iron metabolism in the occurrence and development of periodontitis]

Iron metabolism refers to the process of absorption, transport, excretion and storage of iron in organisms, including the biological activities of iron ions and iron-binding proteins in cells. Clinical research and animal experiments have shown that iron metabolism is associated with the progress of periodontitis. Iron metabolism not only enhances the proliferation and toxicity of periodontal pathogens, but also activate host immune-inflammatory response mediated by macrophages, neutrophils and lymphocytes. In addition, iron metabolism is also involved in regulating cellular death sensitivity of gingival fibroblasts and osteoblasts and promoting the differentiation of osteoclasts, which plays a regulatory role in the regeneration and repair of periodontal tissue. This article reviews the research progress on the pathogenesis of periodontitis from the perspective of iron metabolism, aiming to provide new ideas for the treatment of periodontitis.

The potential roles of HIF-1α in epithelial-mesenchymal transition and ferroptosis in tumor cells

In tumors, the rapid proliferation of cells and the imperfect blood supply system lead to hypoxia, which can regulate the adaptation of tumor cells to the hypoxic environment through hypoxia-inducible factor-1α (HIF-1α) and promote tumor development in multiple ways. Recent studies have found that epithelial-mesenchymal transition (EMT) and ferroptosis play important roles in the progression of tumor cells. The activation of HIF-1α is considered a key factor in inducing EMT in tumor cells. When HIF-1α is activated, it can regulate EMT-related genes, causing tumor cells to gradually lose their epithelial characteristics and acquire more invasive mesenchymal traits. The occurrence of EMT allows tumor cells to better adapt to changes in the surrounding tissue, enhancing their migratory and invasive capabilities, thus promoting tumor progression. At the same time, HIF-1α also plays a crucial regulatory role in ferroptosis in tumor cells. In a hypoxic environment, HIF-1α may affect processes such as iron metabolism and oxidative stress responses, inducing ferroptosis in tumor cells. This article briefly reviews the dual role of HIF-1α in EMT and ferroptosis in tumor cells, helping to gain a deeper understanding of the regulatory pathways of HIF-1α in the development of tumor cells, providing a new perspective for understanding the pathogenesis of tumors. The regulation of HIF-1α may become an important strategy for future tumor therapy.

Metabolic Footprint of Treponema phagedenis and Treponema pedis Reveals Potential Interaction Towards Community Succession and Pathogenesis in Bovine Digital Dermatitis

Bovine digital dermatitis (BDD) is a cattle infection causing hoof lesions and lameness, with treponemes as key pathogens. We analyzed the metabolic activity of Treponema phagedenis and Treponema pedis using gas chromatography-mass spectrometry for organic acids (OAs), amino acids (AAs), and fatty acids (FAs), and high-performance liquid chromatography for short-chain fatty acids (SCFAs). Key findings include a 61.5% reduction in pyruvic acid in T. pedis and 81.0% in T. phagedenis. 2-hydroxybutyric acid increased by 493.8% in T. pedis, while succinic acid increased by 31.3%, potentially supporting T. phagedenis. Among AAs, glycine was reduced by 97.4% in T. pedis but increased by 64.1% in T. phagedenis. Proline increased by 76.6% in T. pedis but decreased by 13.6% in T. phagedenis. Methionine and glutamic acid were competitively utilized, with methionine reduced by 41.8% in T. pedis and 11.9% in T. phagedenis. Both species showed significant utilization of palmitic acid (reduced by 82.8% in T. pedis and 87.2% in T. phagedenis). Butyric acid production increased by 620.2% in T. phagedenis, and propionic acid increased by 932.8% in T. pedis and 395.6% in T. phagedenis. These reveal metabolic interactions between the pathogens, contributing to disease progression and offering insights to BDD pathogenesis.

Integrative microbiome and metabolome profiles reveal the impacts of periodontitis via oral-gut axis in first-trimester pregnant women

BACKGROUND

Periodontitis results from host-microbe dysbiosis and the resultant dysregulated immunoinflammatory response. Importantly, it closely links to numerous systemic comorbidities, and perplexingly contributes to adverse pregnancy outcomes (APOs). Currently, there are limited studies on the distal consequences of periodontitis via oral-gut axis in pregnant women. This study investigated the integrative microbiome-metabolome profiles through multi-omics approaches in first-trimester pregnant women and explored the translational potentials.

METHODS

We collected samples of subgingival plaques, saliva, sera and stool from 54 Chinese pregnant women at the first trimester, including 31 maternal periodontitis (Perio) subjects and 23 Non-Perio controls. By integrating 16S rRNA sequencing, untargeted metabolomics and clinical traits, we explored the oral-gut microbial and metabolic connection resulting from periodontitis among early pregnant women.

RESULTS

We demonstrated a novel bacterial distinguisher Coprococcus from feces of periodontitis subjects in association with subgingival periodontopathogens, being different from other fecal genera in Lachnospiraceae family. The ratio of fecal Coprococcus to Lachnoclostridium could discriminate between Perio and Non-Perio groups as the ratio of subgingival Porphyromonas to Rothia did. Furthermore, there were differentially abundant fecal metabolic features pivotally enriched in periodontitis subjects like L-urobilin and kynurenic acid. We revealed a periodontitis-oriented integrative network cluster, which was centered with fecal Coprococcus and L-urobilin as well as serum triglyceride.

CONCLUSIONS

The current findings about the notable influence of periodontitis on fecal microbiota and metabolites in first-trimester pregnant women via oral-gut axis signify the importance and translational implications of preconceptional oral/periodontal healthcare for enhancing maternal wellbeing.

Non-coding RNAs Function in Periodontal Ligament Stem Cells

Non-coding RNA has many types which has rich functions and plays an important role in the study of basic molecular mechanisms. Many non-coding RNA have important implications for pluripotent stem cells and embryonic stem cells. It has been found to affect the self-renewal and osteogenesis of many types of stem cells. They have also been found to regulate stem cell proliferation and induct bone differentiation. Periodontal ligament stem cells are essential for the regeneration of periodontal tissue. In recent years, in the field of stomatology, studies have found that many non-coding RNA also have significant regulatory effects on the proliferation and differentiation of periodontal stem cells and may become potential therapeutic targets for many common periodontal diseases such as periodontitis, bone/tooth/soft tissue loss and orthodontic treatment. Therefore, we summarized the current research status of non-coding RNA in the field of molecular mechanism of periodontal ligament stem cells and prospected its future progress.

G protein-coupled receptor 91 promotes the inflammatory response to Porphyromonas gingivalis in bone marrow-derived macrophages

Macrophages are important for maintaining tissue homeostasis and defending against pathogens in periodontal tissues. However, these tissues are often vulnerable to damage due to local inflammatory responses within the host tissues. This study aimed to investigate the role of G protein-coupled receptor 91(GPR91) during the inflammatory response to Porphyromonas gingivalis (P. gingivalis) in bone marrow-derived macrophages (BMDMs). To this end, we examined expression levels of GPR91 genes in human periodontal tissues affected by periodontitis. Utilizing primary mouse BMDMs from wild-type (WT) and GPR91 knockout (GPR91-/-) mice infected with P. gingivalis, we demonstrated that GPR91 accumulates in inflamed gingival tissues. Additionally, P. gingivalis can induce intercellular succinate accumulation, inflammatory mediator generation, reactive oxygen species (ROS) production, lipid peroxidation, and superoxide dismutase activity in WT-BMDMs. Moreover, inhibition of GPR91 by the specific inhibitor 4C as well as knockdown of GPR91 reduced inflammation and oxidative stress in P. gingivalis-infected BMDMs. Furthermore, we discovered that GPR91-mediated inflammation in P. gingivalis-infected BMDMs is activated via the Erk/Nuclear Factor-κB pathway. These findings provide new insights into the metabolic pathogenesis of periodontal inflammation.

Effect of luteolin on oxidative stress and inflammation in the human osteoblast cell line hFOB1.19 in an inflammatory microenvironment

BACKGROUND

Periapical lesions are characterized by periapical inflammation and damage to periapical tissues and eventually lead to bone resorption and even tooth loss. H2O2 is widely used in root canal therapy for patients with periapical inflammation. Luteolin possesses high anti-inflammatory, antioxidant, and anticancer potential. However, the underlying mechanism of the efficacy of H2O2 and luteolin on oxidative stress and inflammatory tissue has not been previously addressed. We aimed to investigate the anti-inflammatory and antioxidative effects of luteolin on H2O2-induced cellular oxidative inflammation.

METHODS

After human osteoblasts (hFOB1.19) were treated with lipopolysaccharide (LPS), luteolin, or H2O2, cell proliferation was analysed by using a cell counting kit-8 (CCK-8), cell apoptosis was measured by using flow cytometry, the production of reactive oxygen species (ROS) was evaluated by using an oxidation-sensitive probe DCFH-DA ROS assay kit, and the expression of genes and proteins was detected by using reverse transcription quantitative polymerase chain reaction (RT‒qPCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA).

RESULTS

We demonstrated that inflammation is closely related to oxidative stress and that the oxidative stress level in the inflammatory environment is increased. Luteolin inhibited the H2O2-induced increase in the expression of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor α (TNF-α) and significantly repressed the H2O2-induced increase in ROS, as well as markedly strengthened superoxide dismutase (SOD) activity in hFOB1.19 cells. Moreover, we detected that luteolin may inhibit H2O2-induced hFOB1.19 cell injury by suppressing the NF-κB pathway.

CONCLUSION

We elucidated that luteolin protected human osteoblasts (hFOB1.19) from H2O2-induced cell injury and inhibited the production of proinflammatory cytokines by suppressing the NF-κB signalling pathway. Our findings provide a potential drug for treating H2O2-induced periodontitis and cell injury.

Ferritinophagy: A novel insight into the double-edged sword in ferritinophagy-ferroptosis axis and human diseases

Nuclear receptor coactive 4 (NCOA4), which functions as a selective cargo receptor, is a critical regulator of the particularly autophagic degradation of ferritin, a process known as ferritinophagy. Mechanistically, NCOA4-mediated ferritinophagy performs an increasingly vital role in the maintenance of intracellular iron homeostasis by promoting ferritin transport and iron release as needed. Ferritinophagy is not only involved in iron-dependent responses but also in the pathogenesis and progression of various human diseases, including metabolism-related, neurodegenerative, cardiovascular and infectious diseases. Therefore, ferritinophagy is of great importance in maintaining cell viability and function and represents a potential therapeutic target. Recent studies indicated that ferritinophagy regulates the signalling pathway associated with ferroptosis, a newly discovered type of cell death characterised by iron-dependent lipid peroxidation. Although accumulating evidence clearly demonstrates the importance of the interplay between dysfunction in iron metabolism and ferroptosis, a deeper understanding of the double-edged sword effect of ferritinophagy in ferroptosis has remained elusive. Details of the mechanisms underlying the ferritinophagy-ferroptosis axis in regulating relevant human diseases remain to be elucidated. In this review, we discuss the latest research findings regarding the mechanisms that regulate the biological function of NCOA4-mediated ferritinophagy and its contribution to the pathophysiology of ferroptosis. The important role of the ferritinophagy-ferroptosis axis in human diseases will be discussed in detail, highlighting the great potential of targeting ferritinophagy in the treatment of diseases.

Ferroptosis: Biology and Role in Gastrointestinal Disease

Ferroptosis is a form of nonapoptotic cell death that involves iron-dependent phospholipid peroxidation induced by accumulation of reactive oxygen species, and results in plasma membrane damage and the release of damage-associated molecular patterns. Ferroptosis has been implicated in aging and immunity, as well as disease states including intestinal and liver conditions and cancer. To date, several ferroptosis-associated genes and pathways have been implicated in liver disease. Although ferroptotic cell death is associated with dysfunction of the intestinal epithelium, the underlying molecular basis is poorly understood. As the mechanisms regulating ferroptosis become further elucidated, there is clear potential to use ferroptosis to achieve therapeutic benefit.

High-Throughput Combined Analysis of Saliva Microbiota and Metabolomic Profile in Chinese Periodontitis Patients: A Pilot Study

The onset and progression of periodontitis involves complicated interactions between the dysbiotic oral microbiota and disrupted host immune-inflammatory response, which can be mirrored by the changes in salivary metabolites profile. This pilot study sought to examine the saliva microbiome and metabolome in the Chinese population by the combined approach of 16s rRNA sequencing and high-throughput targeted metabolomics to discover potential cues for host-microbe metabolic interactions. Unstimulated whole saliva samples were collected from eighteen Stage III and IV periodontitis patients and thirteen healthy subjects. Full-mouth periodontal parameters were recorded. The taxonomic composition of microbiota was obtained by 16s rRNA sequencing, and the metabolites were identified and measured by ultra-high performance liquid chromatography and mass spectrometry-based metabolomic analysis. The oral microbiota composition displayed marked changes where the abundance of 93 microbial taxa differed significantly between the periodontitis and healthy group. Targeted metabolomics identified 103 differential metabolites between the patients and healthy individuals. Functional enrichment analysis demonstrated the upregulation of protein digestion and absorption, histidine metabolism, and nicotinate and nicotinamide metabolism pathways in the dysbiotic microbiota, while the ferroptosis, tryptophan metabolism, glutathione metabolism, and carbon metabolism pathways were upregulated in the patients. Correlation analysis confirmed positive relationships between the clinical parameters, pathogen abundances, and disease-related metabolite levels. The integral analysis of the saliva microbiome and metabolome yielded an accurate presentation of the dysbiotic oral microbiome and functional alterations in host-microbe metabolism. The microbial and metabolic profiling of the saliva could be a potential tool in the diagnosis, prognosis evaluation, and pathogenesis study of periodontitis.

International consensus guidelines for the definition, detection, and interpretation of autophagy-dependent ferroptosis

Macroautophagy/autophagy is a complex degradation process with a dual role in cell death that is influenced by the cell types that are involved and the stressors they are exposed to. Ferroptosis is an iron-dependent oxidative form of cell death characterized by unrestricted lipid peroxidation in the context of heterogeneous and plastic mechanisms. Recent studies have shed light on the involvement of specific types of autophagy (e.g. ferritinophagy, lipophagy, and clockophagy) in initiating or executing ferroptotic cell death through the selective degradation of anti-injury proteins or organelles. Conversely, other forms of selective autophagy (e.g. reticulophagy and lysophagy) enhance the cellular defense against ferroptotic damage. Dysregulated autophagy-dependent ferroptosis has implications for a diverse range of pathological conditions. This review aims to present an updated definition of autophagy-dependent ferroptosis, discuss influential substrates and receptors, outline experimental methods, and propose guidelines for interpreting the results.Abbreviation: 3-MA:3-methyladenine; 4HNE: 4-hydroxynonenal; ACD: accidentalcell death; ADF: autophagy-dependentferroptosis; ARE: antioxidant response element; BH2:dihydrobiopterin; BH4: tetrahydrobiopterin; BMDMs: bonemarrow-derived macrophages; CMA: chaperone-mediated autophagy; CQ:chloroquine; DAMPs: danger/damage-associated molecular patterns; EMT,epithelial-mesenchymal transition; EPR: electronparamagnetic resonance; ER, endoplasmic reticulum; FRET: Försterresonance energy transfer; GFP: green fluorescent protein;GSH: glutathione;IF: immunofluorescence; IHC: immunohistochemistry; IOP, intraocularpressure; IRI: ischemia-reperfusion injury; LAA: linoleamide alkyne;MDA: malondialdehyde; PGSK: Phen Green™ SK;RCD: regulatedcell death; PUFAs: polyunsaturated fatty acids; RFP: red fluorescentprotein;ROS: reactive oxygen species; TBA: thiobarbituricacid; TBARS: thiobarbituric acid reactive substances; TEM:transmission electron microscopy.

Lipotoxicity: The missing link between diabetes and periodontitis?

Lipotoxicity refers to the accumulation of lipids in tissues other than adipose tissue (body fat). It is one of the major pathophysiological mechanisms responsible for the progression of diabetes complications such as non-alcoholic fatty liver disease and diabetic nephropathy. Accumulating evidence indicates that lipotoxicity also contributes significantly to the toxic effects of diabetes on periodontitis. Therefore, we reviewed the current in vivo, in vitro, and clinical evidence of the detrimental effects of lipotoxicity on periodontitis, focusing on its molecular mechanisms, especially oxidative and endoplasmic reticulum stress, inflammation, ceramides, adipokines, and programmed cell death pathways. By elucidating potential therapeutic strategies targeting lipotoxicity and describing their associated mechanisms and clinical outcomes, including metformin, statins, liraglutide, adiponectin, and omega-3 PUFA, this review seeks to provide a more comprehensive and effective treatment framework against diabetes-associated periodontitis. Furthermore, the challenges and future research directions are proposed, aiming to contribute to a more profound understanding of the impact of lipotoxicity on periodontitis.

Exploring the molecular mechanisms of ferroptosis-related genes in periodontitis: a multi-dataset analysis

PURPOSE

This study aims to elucidate the biological functions of ferroptosis-related genes in periodontitis, along with their correlation to tumor microenvironment (TME) features such as immune infiltration. It aims to provide potential diagnostic markers of ferroptosis for clinical management of periodontitis.

METHODS

Utilizing the periodontitis-related microarray dataset GSE16134 from the Gene Expression Omnibus (GEO) and a set of 528 ferroptosis-related genes identified in prior studies, this research unveils differentially expressed ferroptosis-related genes in periodontitis. Subsequently, a protein-protein interaction network was constructed. Subtyping of periodontitis was explored, followed by validation through immune cell infiltration and gene set enrichment analyses. Two algorithms, randomForest and SVM(Support Vector Machine), were employed to reveal potential ferroptosis diagnostic markers for periodontitis. The diagnostic efficacy, immune correlation, and potential transcriptional regulatory networks of these markers were further assessed. Finally, potential targeted drugs for differentially expressed ferroptosis markers in periodontitis were predicted.

RESULTS

A total of 36 ferroptosis-related genes (30 upregulated, 6 downregulated) were identified from 829 differentially expressed genes between 9 periodontitis samples and the control group. Subsequent machine learning algorithm screening highlighted 4 key genes: SLC1A5(Solute Carrier Family 1 Member 5), SLC2A14(Solute Carrier Family 1 Member 14), LURAP1L(Leucine Rich Adaptor Protein 1 Like), and HERPUD1(Homocysteine Inducible ER Protein With Ubiquitin Like Domain 1). Exploration of these 4 key genes, supported by time-correlated ROC analysis, demonstrated reliability, while immune infiltration results indicated a strong correlation between key genes and immune factors. Furthermore, Gene Set Enrichment Analysis (GSEA) was conducted for the four key genes, revealing enrichment in GO/KEGG pathways that have a significant impact on periodontitis. Finally, the study predicted potential transcriptional regulatory networks and targeted drugs associated with these key genes in periodontitis.

CONCLUSIONS

The ferroptosis-related genes identified in this study, including SLC1A5, SLC2A14, LURAP1L, and HERPUD1, may serve as novel diagnostic and therapeutic targets for periodontitis. They are likely involved in the occurrence and development of periodontitis through mechanisms such as immune infiltration, cellular metabolism, and inflammatory chemotaxis, potentially linking the ferroptosis pathway to the progression of periodontitis. Targeted drugs such as flurofamide, L-733060, memantine, tetrabenazine, and WAY-213613 hold promise for potential therapeutic interventions in periodontitis associated with these ferroptosis-related genes.

A multi-platform analysis of human gingival crevicular fluid reveals ferroptosis as a relevant regulated cell death mechanism during the clinical progression of periodontitis

Ferroptosis is implicated in the pathogenesis of numerous chronic-inflammatory diseases, yet its association with progressive periodontitis remains unexplored. To investigate the involvement and significance of ferroptosis in periodontitis progression, we assessed sixteen periodontitis-diagnosed patients. Disease progression was clinically monitored over twelve weeks via weekly clinical evaluations and gingival crevicular fluid (GCF) collection was performed for further analyses. Clinical metrics, proteomic data, in silico methods, and bioinformatics tools were combined to identify protein profiles linked to periodontitis progression and to explore their potential connection with ferroptosis. Subsequent western blot analyses validated key findings. Finally, a single-cell RNA sequencing (scRNA-seq) dataset (GSE164241) for gingival tissues was analyzed to elucidate cellular dynamics during periodontitis progression. Periodontitis progression was identified as occurring at a faster rate than traditionally thought. GCF samples from progressing and non-progressing periodontal sites showed quantitative and qualitatively distinct proteomic profiles. In addition, specific biological processes and molecular functions during progressive periodontitis were revealed and a set of hub proteins, including SNCA, CA1, HBB, SLC4A1, and ANK1 was strongly associated with the clinical progression status of periodontitis. Moreover, we found specific proteins - drivers or suppressors - associated with ferroptosis (SNCA, FTH1, HSPB1, CD44, and GCLC), revealing the co-occurrence of this specific type of regulated cell death during the clinical progression of periodontitis. Additionally, the integration of quantitative proteomic data with scRNA-seq analysis suggested the susceptibility of fibroblasts to ferroptosis. Our analyses reveal proteins and processes linked to ferroptosis for the first time in periodontal patients, which offer new insights into the molecular mechanisms of progressive periodontal disease. These findings may lead to novel diagnostic and therapeutic strategies.

Effects of the ferroptosis inducer erastin on osteogenic differentiation and biological pathways of primary osteoblasts

BACKGROUND

Periodontitis is a chronic destructive inflammatory disease exacerbated by osteoblast dysfunction. Ferroptosis has emerged as a significant factor that could contribute to the pathological changes observed in periodontitis. However, the impact of ferroptosis on osteogenic differentiation and gene expression patterns of primary osteoblasts remain elusive.

METHODS

In this study, osteoblasts were osteogenically induced for specific durations with and without the ferroptosis inducer erastin. Subsequently, cell proliferation, ferroptosis-related molecules, and osteogenic differentiation capacity were assessed. Furthermore, the differences in transcriptome expression following erastin treatment were analyzed by RNA sequencing.

RESULTS

The results demonstrated that erastin treatment induced ferroptosis, resulting in suppressed cell proliferation and impaired osteogenic differentiation. Transcriptomic analysis revealed significant alterations in processes such as hydrogen peroxide catabolism, response to lipid peroxidation, and metal iron binding, as well as BMP receptor activity and collagen type XI trimer.

CONCLUSION

The ferroptosis inducer erastin inhibited osteoblast proliferation and differentiation. Our study provides novel insights into the effect of ferroptosis on osteogenesis, suggesting that targeting ferroptosis may present a promising approach in the treatment of periodontitis.

Gut microbiome, short-chain fatty acids, alpha-synuclein, neuroinflammation, and ROS/RNS: Relevance to Parkinson's disease and therapeutic implications

In this review, we explore how short-chain fatty acids (SCFAs) produced by the gut microbiome affect Parkinson's disease (PD) through their modulatory interactions with alpha-synuclein, neuroinflammation, and oxidative stress mediated by reactive oxygen and nitrogen species (ROS/RNS). In particular, SCFAs-such as acetate, propionate, and butyrate-are involved in gut-brain communication and can modulate alpha-synuclein aggregation, a hallmark of PD. The gut microbiome of patients with PD has lower levels of SCFAs than healthy individuals. Probiotics may be a potential strategy to restore SCFAs and alleviate PD symptoms, but the underlying mechanisms are not fully understood. Also in this review, we discuss how alpha-synuclein, present in the guts and brains of patients with PD, may induce neuroinflammation and oxidative stress via ROS/RNS. Alpha-synuclein is considered an early biomarker for PD and may link the gut-brain axis to the disease pathogenesis. Therefore, elucidating the role of SCFAs in the gut microbiome and their impact on alpha-synuclein-induced neuroinflammation in microglia and on ROS/RNS is crucial in PD pathogenesis and treatment.

Butyrate attenuates the stemness of lung cancer cells through lysosome Fe2+- and SLC7A11-mediated ferroptosis

Cancer stem cells (CSCs) are considered key contributors to tumor progression, and ferroptosis has been identified as a potential target for CSCs. We have previously shown that butyrate enhances the ferroptosis induced by erastin in lung cancer cell, this study aimed to investigate the impact of butyrate on the progression of lung CSCs. To investigate these effects, we constructed a series of in vitro experiments, including 3D non-adherent sphere-formation, cytometry analysis, assessment of CSC marker expression, cell migration assay, and in vivo tumorigenesis analyses. Additionally, the influence of butyrate on chemotherapeutic sensitivity were determined through both in vitro and in vivo experiments. Mechanistically, immunofluorescence analysis was employed to examine the localization of biotin-conjugated butyrate. We identified that butyrate predominantly localized in the lysosome and concurrently recruited Fe2+ in lysosome. Moreover, butyrate reduced the stability of SLC7A11 protein stability in lung cancer cells through ubiquitination and proteasome degradation. Importantly, the effects of butyrate on lung CSCs were found to be dependent on lysosome Fe2+- and SLC7A11-mediated ferroptosis. In summary, our results demonstrate that butyrate could induce the ferroptosis in lung CSCs by recruiting Fe2+ in lysosome and promoting the ubiquitination-lysosome degradation of SLC7A11 protein.

Role of ferroptosis in Porphyromonas gingivalis-induced impairment of epithelial junction

Objectives

This study aims to clarify the effect of ferroptosis by P. gingivalis on periodontal epithelium impairment and potential mechanisms.

Materials and methods

The expression of epithelial junction proteins (CDH1, OCLN, ZO-1), FTL and GPX4 in healthy and periodontitis tissues was analyzed using bioinformatics analysis and validated in vivo. An in vitro model was constructed to evaluate ferroptosis by mitochondria morphology, content of iron and GSH, and level of lipid peroxidation, FTL, GPX4 and SLC7A11. The iron concentration was changed with iron chelator DFO and iron supplementation FAC. The epithelial impairment was assessed by protein expression. To investigate the mechanism, si-MYB (a negative transcription factor of SLC7A11) and GPX4 inhibitor RSL3 were employed.

Results

CDH1, OCLN, ZO-1 and GPX4 expression was decreased, while FTL expression was elevated in periodontitis tissues. Infected cells showed ferroptosis change of the mitochondria with higher level of lipid peroxidation, iron, FTL and lower level of GPX4, GSH, SLC7A11. FAC augmented ferroptosis and weakened epithelial junction, while DFO exhibited a counteractive effect. Silencing MYB rescued SLC7A11, GPX4 and epithelial junction proteins, which was hindered by RSL3.

Conclusions

Our study demonstrated that P. gingivalis weakened the oral epithelial barrier by causing ferroptosis via inhibiting SLC7A11/GSH/GPX4 axis.

Inhibition of ZDHHC16 promoted osteogenic differentiation and reduced ferroptosis of dental pulp stem cells by CREB

BACKGROUND

The repair of bone defects caused by periodontal diseases is a difficult challenge in clinical treatment. Dental pulp stem cells (DPSCs) are widely studied for alveolar bone repair. The current investigation aimed to examine the specific mechanisms underlying the role of Zinc finger DHHC-type palmitoyl transferases 16 (ZDHHC16) in the process of osteogenic differentiation (OD) of DPSCs.

METHODS

The lentiviral vectors ZDHHC16 or si-ZDHHC16 were introduced in the DPSCs and then the cells were induced by an odontogenic medium for 21 days. Subsequently, Quantitate Polymerase Chain Reaction (PCR), immunofluorescent staining, proliferation assay, ethynyl deoxyuridine (EdU) staining, and western blot analysis were used to investigate the specific details of ZDHHC16 contribution in OD of DPSCs.

RESULTS

Our findings indicate that ZDHHC16 exhibited a suppressive effect on cellular proliferation and oxidative phosphorylation, while concurrently inducing ferroptosis in DPSCs. Moreover, the inhibition of ZDHHC16 promoted cell development and OD and reduced ferroptosis of DPSCs. The expression of p-CREB was suppressed by ZDHHC16, and immunoprecipitation (IP) analysis revealed that ZDHHC16 protein exhibited interconnection with cAMP-response element binding protein (CREB) of DPSCs. The CREB suppression reduced the impacts of ZDHHC16 on OD and ferroptosis of DPSCs. The activation of CREB also reduced the influences of si-ZDHHC16 on OD and ferroptosis of DPSCs.

CONCLUSIONS

These findings provide evidences to support a negative association between ZDHHC16 and OD of DPSCs, which might be mediated by ferroptosis of DPSCs via CREB.

Exploring the effect of butyric acid, a metabolite from periodontopathic bacteria, on primary human melanocytes: An in vitro study

Effects of butyric acid, a bacterial metabolite implicated in periodontitis progression, have never been examined on oral melanocytes. Herein, primary human epidermal melanocytes were used as a model for oral melanocytes. Results show the adverse effects of butyric acid (sodium butyrate; NaB) on them, which comprise marked cytotoxicity at higher concentrations (>1 mM) and robust differentiation at lower nontoxic concentrations. NaB did not alter MITF protein levels; however, it stimulated tyrosinase protein synthesis and inhibited tyrosinase activity, with no changes in cellular melanin. NaB did not affect oxidative stress, although it induced significant levels of the pro-inflammatory cytokine IL-6.

NCOA4-mediated ferritinophagy aggravate intestinal oxidative stress and ferroptosis after traumatic brain injury

Intestinal injury caused by traumatic brain injury (TBI) seriously affects patient prognosis; however, the underlying mechanisms are unknown. Recent studies have demonstrated that ferritinophagy-mediated ferroptosis is involved in several intestinal disorders. However, uncertainty persists regarding the role of ferritinophagy-mediated ferroptosis in the intestinal damage caused by TBI. High-throughput transcriptional sequencing was used to identify the genes that were differentially expressed in the intestine after TBI. The intestinal tissues were harvested for hematoxylin and eosin staining (HE), immunofluorescence, and western blot (WB). Lipid peroxide markers and iron content in the intestines were determined using the corresponding kits. High throughput sequencing revealed that the ferroptosis signaling pathway was enriched, demonstrating that intestinal damage caused by TBI may include ferroptosis. Chiu's score, tight junction proteins, and lipid peroxide indicators demonstrated that TBI caused an intestinal mucosal injury that persisted for several days. The ferroptosis pathway-related proteins, ferritin heavy polypeptide 1 (Fth1) and glutathione peroxidase 4 (GPX4), exhibited dynamic changes. The results indicated that lipid peroxide products were markedly increased, whereas antioxidant enzymes were markedly decreased. WB analysis demonstrated that the expression levels of nuclear receptor coactivator 4 (NCOA4), LC3II/LC3I, and p62 were markedly upregulated, whereas those of GPX4 and Fth1 were markedly downregulated. In addition, ferrostatin-1 attenuates intestinal ferroptosis and injury post-TBI in vivo. Intriguingly, 3-methyladenine (3-MA) reduces intestinal ferritin decomposition, iron accumulation, and ferroptosis after TBI. Moreover, 3-MA markedly reduced intestinal apoptosis. In conclusion, NCOA4 mediated ferritinophagy and ferroptosis play roles in intestinal oxidative stress injury post-TBI. This study provides a deeper understanding of the mechanisms underlying intestinal damage following TBI.

Clostridium butyricum and its metabolite butyrate promote ferroptosis susceptibility in pancreatic ductal adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited therapeutic options. The diversity and composition of the intratumoral microbiota are associated with PDAC outcomes, and modulating the tumor microbiota has the potential to influence tumor growth and the host immune response. Here, we explore whether intervention with butyrate-producing probiotics can limit PDAC progression.

METHODS

Based on the TCGA (PAAD) database, we analyzed the differential communities of intratumoral microbiota in PDAC patients with long survival and short survival and explored the relevant mechanisms of Clostridium butyricum and its metabolite butyrate in the treatment of PDAC. Treatment with Clostridium butyricum or butyrate in combination with the ferroptosis inducer RSL3 in a PDAC mouse model has an inhibitory effect on PDAC progression. The potential molecular mechanisms were verified by flow cytometry, RNA-seq, Western blotting, qRT‒PCR and immunofluorescence.

RESULTS

We found that the tumoral butyrate-producing microbiota was linked to a better prognosis and less aggressive features of PDAC. Intervention with Clostridium butyricum or its metabolite butyrate triggered superoxidative stress and intracellular lipid accumulation, which enhanced ferroptosis susceptibility in PDAC.

CONCLUSION

Our study reveals a novel antitumor mechanism of butyrate and suggests the therapeutic potential of butyrate-producing probiotics in PDAC.

The Complicated Relationship of Short-Chain Fatty Acids and Oral Microbiome: A Narrative Review

The human oral microbiome has emerged as a focal point of research due to its profound implications for human health. The involvement of short-chain fatty acids in oral microbiome composition, oral health, and chronic inflammation is gaining increasing attention. In this narrative review, the results of early in vitro, in vivo, and pilot clinical studies and research projects are presented in order to define the boundaries of this new complicated issue. According to the results, the current research data are disputable and ambiguous. When investigating the role of SCFAs in human health and disease, it is crucial to distinguish between their local GI effects and the systemic influences. Locally, SCFAs are a part of normal oral microbiota metabolism, but the increased formation of SCFAs usually attribute to dysbiosis; excess SCFAs participate in the development of local oral diseases and in oral biota gut colonization and dysbiosis. On the other hand, a number of studies have established the positive impact of SCFAs on human health as a whole, including the reduction of chronic systemic inflammation, improvement of metabolic processes, and decrease of some types of cancer incidence. Thus, a complex and sophisticated approach with consideration of origin and localization for SCFA function assessment is demanded. Therefore, more research, especially clinical research, is needed to investigate the complicated relationship of SCFAs with health and disease and their potential role in prevention and treatment.

Role of ferroptosis in periodontitis: An animal study in rats

OBJECTIVE

This study aimed to investigate (1) the temporal pattern of ferroptosis, an iron-dependent cell death, in ligation-induced rat periodontitis and (2) the effect of ferrostatin-1, a ferroptosis inhibitor, on the model.

BACKGROUND

Ferroptosis may contribute to various diseases. However, the role of ferroptosis in periodontitis is still fully understood.

METHODS

In the first experiment, 25 rats with ligation-induced periodontitis were sacrificed on days 0, 1, 2, 7, and 10. Gingivae were obtained to determine tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and ferroptotic biomarkers, including solute carrier family 3 member 2 (SLC3A2) and solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (Gpx4), via immunoblotting. Using microcomputed tomography (μCT) and histology, the periodontal soft and hard tissue lesions, including dental alveolar bone crest level, bony characteristics of the surrounding alveolus, periodontal tissue inflammation, and periodontal tissue losses, were evaluated. In study two, 16 rats with induced periodontitis were grouped according to ferrostatin-1 treatment. The rats were intraperitoneally injected with solvent or ferrostatin-1 (1.5 mg/kg/day) 1 day before ligation and sacrificed on days 7 and 10. Gingival protein changes and periodontal tissue damage were also examined.

RESULTS

In study one, SLC3A2/SLC7A11 and Gpx4 decreased since day 1; however, TNF-α/IL-1β increased on days 7 and 10. Moreover, the μCT/histology revealed resorptive bony characteristics, inflamed gingival tissue, and periodontal attachment loss. In study two, ferrostatin-1-injected rats exhibited significantly increased SLC3A2/SLC7A11 and Gpx4 but decreased TNF-α/IL-1β than vehicle rats. They also revealed lessened bone resorption, tissue inflammation, and attachment loss.

CONCLUSION

This study highlights the role of ferroptosis, via the system Xc/Gpx4 pathway, in experimental periodontitis and may serve as a regulatory strategy.

Periodontitis contributes to COPD progression via affecting ferroptosis

BACKGROUND

Periodontitis has emerged as a potential risk factor for chronic obstructive pulmonary disease (COPD). However, the precise mechanism through which periodontitis influences the progression of COPD requires further investigation. Ferroptosis is one of the crucial pathogenesis of COPD and recent researches suggested that periodontitis was associated with ferroptosis. Nonetheless, the relationship among periodontitis, COPD and ferroptosis remains unclear. This study aimed to elucidate whether periodontitis contributes to COPD exacerbation and to assess the potential impact of ferroptosis on periodontitis affecting COPD.

METHODS

The severity of COPD was assessed using Hematoxylin and eosin (H&E) staining and lung function tests. Iron assays, malondialdehyde (MDA) measurement and RT-qPCR were used to investigate the potential involvement of ferroptosis in the impact of periodontitis on COPD. Co-cultures of periodontitis associated pathogen Phophyromonas gingivalis (P. gingivalis) and lung tissue cells were used to evaluate the effect of P. gingivalis on inducing the ferroptosis of lung tissue via RT-qPCR analysis. Clinical Bronchoalveolar Lavage Fluid (BALF) samples from COPD patients were collected to further validate the role of ferroptosis in periodontal pathogen-associated COPD.

RESULTS

Periodontitis aggravated the COPD progression and the promotion was prolonged over time. For the first time, we demonstrated that periodontitis promoted the ferroptosis-associated iron accumulation, MDA contents and gene expressions in the COPD lung with a time-dependent manner. Moreover, periodontitis-associated pathogen P. gingivalis could promote the ferroptosis-associated gene expression in single lung tissue cell suspensions. Clinical BALF sample detection further indicated that ferroptosis played essential roles in the periodontal pathogen-associated COPD.

CONCLUSION

Periodontitis could contribute to the exacerbation of COPD through up-regulating the ferroptosis in the lung tissue.

High-Dose Ionizing Radiation Accelerates Atherosclerotic Plaque Progression by Regulating P38/NCOA4-Mediated Ferritinophagy/Ferroptosis of Endothelial Cells

PURPOSE

Radiation therapy (RT) significantly increased the incidence of coronary artery diseases, especially atherosclerosis. Endothelial dysfunction has been the major side effect of RT among tumor patients who received RT. However, the involvement between endothelial dysfunction and radiation-induced atherosclerosis (RIA) remains unclear. Here, we constructed a murine model of RIA, aiming to uncover its underlying mechanisms and identify novel strategies for RIA prevention and treatment.

METHODS AND MATERIALS

Eight-week-old ApoE-/- mice that were fed a Western diet were subjected to partial carotid ligation (PCL). Four weeks later, ionizing radiation (IR) of 10 Gy was performed to verify the detrimental role of IR on atherogenesis. Ultrasound imaging, RT quantitative polymerase chain reaction, histopathology and immunofluorescence, and biochemical analysis were performed 4 weeks after IR. To study the involvement of endothelial ferroptosis induced by IR in RIA, mice after IR were administrated with ferroptosis agonist (cisplatin) or antagonist (ferrostatin-1) intraperitoneally. Western blotting, autophagic flux measurement, reactive oxygen species level detection, and coimmunoprecipitation assay were carried out in vitro. Furthermore, to determine the effect of ferritinophagy inhibition on RIA, in vivo knockdown of NCOA4 was carried out by pluronic gel.

RESULTS

We verified that accelerated plaque progression was concomitant with endothelial cell (EC) ferroptosis after IR induction, as suggested by a higher level of lipid peroxidation and changes in ferroptosis-associated genes in the PCL + IR group than in the PCL group within vasculature. In vitro experiments further validated the devastating effects of IR on oxidative stress and ferritinophagy in ECs. Mechanistic experiments revealed that IR induced EC ferritinophagy and subsequent ferroptosis in a P38/NCOA4-dependent manner. Both in vitro and in vivo experiments confirmed the therapeutic effect of NCOA4 knockdown in alleviating IR-induced ferritinophagy/ferroptosis of EC and RIA.

CONCLUSIONS

Our findings provide novel insights into the regulatory mechanisms of RIA and first prove that IR accelerates atherosclerotic plaque progression by regulating ferritinophagy/ferroptosis of ECs in a P38/NCOA4-dependent manner.

Reactive Oxygen Species and Ferroptosis at the Nexus of Inflammation and Colon Cancer

Significance: Reactive oxygen species (ROS) are essential in maintaining normal intestinal physiology. Inflammatory bowel disease (IBD) is a relapsing chronic inflammatory disease of the intestine that is a major risk factor for colorectal cancer (CRC). Excess ROS are widely implicated in intestinal inflammation and cancer. Recent Advances: Clinical data have shown that targeting ROS broadly does not yield improved outcomes in IBD and CRC. However, selectively limiting oxidative damage may improve the efficacy of ROS targeting. An accumulation of lipid ROS induces a novel oxidative cell death pathway known as ferroptosis. A growing body of evidence suggests that ferroptosis is relevant to both IBD and CRC. Critical Issues: We propose that inhibition of ferroptosis will improve disease severity in IBD, whereas activating ferroptosis will limit CRC progression. Data from preclinical models suggest that methods of modulating ferroptosis have been successful in attenuating IBD and CRC. Future Directions: The etiology of IBD and progression of IBD to CRC are still unclear. Further understanding of ferroptosis in intestinal diseases will provide novel therapies. Ferroptosis is highly linked to inflammation, cell metabolism, and is cell-type dependent. Further research in assessing the inflammatory and tumor microenvironment in the intestine may provide novel vulnerabilities that can be targeted. Antioxid. Redox Signal. 39, 551-568.

HP1 induces ferroptosis of renal tubular epithelial cells through NRF2 pathway in diabetic nephropathy

The aim of this study was to investigate the role of ferroptosis in diabetic nephropathy (DN) and the mechanism of its regulatory genes. HK-2 cells were cultured with high glucose and mice were intraperitoneally injected with streptozotocin to establish DN models. GSE111154 was analyzed to identify the abnormal expression of genes associated with DN. Cell injury was evaluated through CCK-8 assay and 4',6-diamidino-2-phenylindole/phenylindole double staining. The levels of iron, glutathione, malondialdehyde, urinary albumin, and urinary creatinine were determined by ELISA. Furthermore, western blot and RT-qPCR were used to detect protein and mRNA levels, respectively. Our data showed that heterochromatin protein 1 is an abnormally elevated gene related to DN and is further elevated by ferroptosis activators. Inhibition of HP1 significantly inhibited ferroptosis but promoted cell viability. In addition, nuclear factor erythroid2-related factor2 (NRF2) was decreased in DN cell model, but increased under the action of ferroptosis activators. NRF2 silencing reversed the protective effects of HP1 inhibition on HK-2 cells. Additionally, HP1 silencing also alleviated kidney damage in DN mice. Collectively, these findings suggest that inhibiting HP1 inhibits ferroptosis via NRF2 pathway, thereby protecting renal tubular epithelial cells from damage.

Programmed cell death of periodontal ligament cells

The periodontal ligament is a crucial tissue that provides support to the periodontium. Situated between the alveolar bone and the tooth root, it consists primarily of fibroblasts, cementoblasts, osteoblasts, osteoclasts, periodontal ligament stem cells (PDLSCs), and epithelial cell rests of Malassez. Fibroblasts, cementoblasts, osteoblasts, and osteoclasts are functionally differentiated cells, whereas PDLSCs are undifferentiated mesenchymal stem cells. The dynamic development of these cells is intricately linked to periodontal changes and homeostasis. Notably, the regulation of programmed cell death facilitates the clearance of necrotic tissue and plays a pivotal role in immune response. However, it also potentially contributes to the loss of periodontal supporting tissues and root resorption. These findings have significant implications for understanding the occurrence and progression of periodontitis, as well as the mechanisms underlying orthodontic root resorption. Further, the regulation of periodontal ligament cell (PDLC) death is influenced by both systemic and local factors. This comprehensive review focuses on recent studies reporting the mechanisms of PDLC death and related factors.

Curcumin Attenuates Periodontal Injury via Inhibiting Ferroptosis of Ligature-Induced Periodontitis in Mice

Periodontitis is a chronic infectious disease characterized by the destruction of connective tissue and alveolar bone that eventually leads to tooth loss. Ferroptosis is an iron-dependent regulated cell death and is involved in ligature-induced periodontitis in vivo. Studies have demonstrated that curcumin has a potential therapeutic effect on periodontitis, but the mechanism is still unclear. The purpose of this study was to investigate the protective effects of curcumin on alleviating ferroptosis in periodontitis. Ligature-induced periodontal-diseased mice were used to detect the protective effect of curcumin. The level of superoxide dismutase (SOD), malondialdehyde (MDA) and total glutathione (GSH) in gingiva and alveolar bone were assayed. Furthermore, the mRNA expression levels of acsl4, slc7a11, gpx4 and tfr1 were measured using qPCR and the protein expression of ACSL4, SLC7A11, GPX4 and TfR1 were investigated by Western blot and immunocytochemistry (IHC). Curcumin reduced the level of MDA and increased the level of GSH. Additionally, curcumin was proven to significantly increase the expression levels of SLC7A11 and GPX4 and inhibit the expression of ACSL4 and TfR1. In conclusion, curcumin plays a protective role by inhibiting ferroptosis in ligature-induced periodontal-diseased mice.

Identification of hub cuproptosis related genes and immune cell infiltration characteristics in periodontitis

Introduction

Periodontitis is an inflammatory disease and its molecular mechanisms is not clear. A recently discovered cell death pathway called cuproptosis, may related to the disease.

Methods

The datasets GSE10334 of human periodontitis and control were retrieved from the Gene Expression Omnibus database (GEO) for analysis.Following the use of two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature removal (SVM-RFE) were used to find CRG-based signature. Then the Receiver operating characteristic (ROC) curves was used to evaluate the gene signature's discriminatory ability. The CIBERSORT deconvolution algorithm was used to study the link between hub genes and distinct types of immune cells. Next, the association of the CRGs with immune cells in periodontitis and relevant clusters of cuproptosis were found. The link between various clusters was ascertained by the GSVA and CIBERSORT deconvolution algorithm. Finally, An external dataset (GSE16134) was used to confirm the diagnosis capacity of the identified biomarkers. In addition, clinical samples were examined using qRT-PCR and immunohistochemistry to verifiy the expression of genes related to cuprotosis in periodontitis and the signature may better predict the periodontitis.

Results

15 periodontitis-related DE-CRGs were found,then 11-CRG-based signature was found by using of LASSO and SVM-RFE. ROC curves also supported the value of signature. CIBERSORT results of immune cell signature in periodontitis showed that signature genes is a crucial component of the immune response.The relevant clusters of cuproptosis found that the NFE2L2, SLC31A1, FDX1,LIAS, DLD, DLAT, and DBT showed a highest expression levels in Cluster2 ,while the NLRP3, MTF1, and DLST displayed the lowest level in Cluster 2 but the highest level in Cluster1. The GSVA results also showed that the 11 cuproptosis diagnostic gene may regulate the periodontitis by affecting immune cells. The external dataset (GSE16134) confirm the diagnosis capacity of the identified biomarkers, and clinical samples examined by qRT-PCR and immunohistochemistry also verified that these cuprotosis related signiture genes in periodontitis may better predict the periodontitis.

Conclusion

These findings have important implications for the cuproptosis and periodontitis, and highlight further research is needed to better understand the mechanisms underlying this relationship between the cuproptosis and periodontitis.

Butyrate dictates ferroptosis sensitivity through FFAR2-mTOR signaling

Evidence shows that short-chain fatty acids (SCFAs) play an important role in health maintenance and disease development. In particular, butyrate is known to induce apoptosis and autophagy. However, it remains largely unclear whether butyrate can regulate cell ferroptosis, and the mechanism by which has not been studied. In this study, we found that RAS-selective lethal compound 3 (RSL3)- and erastin-induced cell ferroptosis were enhanced by sodium butyrate (NaB). With regard to the underlying mechanism, our results showed that NaB promoted ferroptosis by inducing lipid ROS production via downregulating the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). Moreover, the FFAR2-AKT-NRF2 axis and FFAR2-mTORC1 axis accounts for the NaB-mediated downregulation of SLC7A11 and GPX4, respectively, in a cAMP-PKA-dependent manner. Functionally, we found that NaB can inhibit tumor growth and the inhibitory effect could be eliminated by administrating MHY1485 (mTORC1 activator) and Ferr-1 (ferroptosis inhibitor). Altogether, in vivo results suggest that NaB treatment is correlated to the mTOR-dependent ferroptosis and consequent tumor growth through xenografts and colitis-associated colorectal tumorigenesis, implicating the potential clinical applications of NaB for future colorectal cancer treatments. Based on all these findings, we have proposed a regulatory mechanism via which butyrate inhibits the mTOR pathway to control ferroptosis and consequent tumorigenesis.

Ferritinophagy in the etiopathogenic mechanism of related diseases

Iron is an essential trace element that is involved in a variety of physiological processes. Ferritinophagy is selective autophagy mediated by nuclear receptor coactivator 4 (NCOA4), which regulates iron homeostasis in the body. Upon iron depletion or starvation, ferritinophagy is activated, releasing large amounts of Fe²⁺ and increasing reactive oxygen species (ROS), leading to ferroptosis. This plays a significant role in the etiopathogenesis of many diseases, such as metabolic diseases, neurodegenerative diseases, infectious diseases, tumors, cardiomyopathy, and ischemia-reperfusion ischemia-reperfusion injury. Here, we first review the regulation and functions of ferritinophagy and then describe its involvement in different diseases, with hopes of providing new understanding and insights into iron metabolism and iron disorder-related diseases and the therapeutic opportunity for targeting ferritinophagy.

Development of Ferroptosis-Associated ceRNA Network in Periodontitis

OBJECTIVES

Periodontitis is a chronic inflammatory illness that may lead to tooth loosening and even loss, and its pathogenesis is not fully understood. Ferroptosis is an iron-dependent, regulated cell death. The present study aims to find the key ferroptosis-related genes (FRGs) in periodontitis and develop an mRNA-miRNA-lncRNA network to deeply explore the pathogenesis of periodontitis.

METHODS

Data from the Gene Expression Omnibus (GEO) database and FerrDb database were downloaded to discover the differentially expressed mRNA, miRNA, and FRGs. Functional enrichment analysis was conducted for the differentially expressed FRGs (DE-FRGs), including gene ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein-protein interaction (PPI) network analysis. Targetscan and miRtarbase were used to estimate the miRNAs that DE-FRGs may interact with, whilst StarBase v3.0 was used for lncRNA-miRNA interaction.

RESULTS

Seven DE-FRGs were identified through differential expression analysis. Interleukin 1 beta (IL1B) interacted with XBP1 and MMP13 in the PPI network. After taking the intersection between DE-miRNAs and predicted miRNAs, a ceRNA network containing IL1B, has-miR-185, has-miR-204, has-miR-211, has-miR-4306, and 28 lncRNAs was established.

CONCLUSIONS

Seven FRGs in periodontitis were identified, which might promote deeper understanding of ferroptosis in periodontitis.

Development of a classification model and an immune-related network based on ferroptosis in periodontitis

BACKGROUND AND OBJECTIVES

Periodontitis is an immunoinflammatory disease characterized by irreversible periodontal attachment loss and bone destruction. Ferroptosis is a kind of immunogenic cell death that depends on the participation of iron ions and is involved in various inflammatory and immune processes. However, information regarding the relationship between ferroptosis and immunomodulation processes in periodontitis is extremely limited. The purpose of this study was to investigate the correlation between ferroptosis and immune responses in periodontitis.

METHODS

Gene expression profiles of gingivae were collected from the Gene Expression Omnibus data portal. After detecting differentially expressed ferroptosis-related genes (FRGs), we used univariate logistic regression analysis followed by logistic least absolute shrinkage and selection operator (LASSO) regression to establish a ferroptosis-related classification model in an attempt to accurately distinguish periodontitis gingival tissues from healthy samples. The infiltration level of immunocytes in periodontitis was then assessed through single-sample gene-set enrichment analysis. Subsequently, we screened out immune-related genes by weighted correlation network analysis and protein-protein interaction (PPI) analysis and constructed an immune-related network based on FRGs and immune-related genes.

RESULTS

A total of 24 differentially expressed FRGs were detected, and an 8-FRG combined signature constituted the classification model. The established model showed outstanding discriminating ability according to the results of receiver operating characteristic (ROC) curve analysis. In addition, the periodontitis samples had a higher degree of immunocyte infiltration. Activated B cells had the strongest positive correlation while macrophages had a strong negative correlation with certain FRGs, and we found that XBP1, ALOX5 and their interacting genes might be crucial genes in the immune-related network.

CONCLUSIONS

The FRG-based classification model had a satisfactory determination ability, which could bring new insights into the pathogenesis of periodontitis. Those genes in the immune-related network, especially hub genes along with XBP1 and ALOX5, would have the potential to serve as promising targets of immunomodulatory treatments for periodontitis.

Study of the inflammatory activating process in the early stage of Fusobacterium nucleatum infected PDLSCs

Fusobacterium nucleatum (F. nucleatum) is an early pathogenic colonizer in periodontitis, but the host response to infection with this pathogen remains unclear. In this study, we built an F. nucleatum infectious model with human periodontal ligament stem cells (PDLSCs) and showed that F. nucleatum could inhibit proliferation, and facilitate apoptosis, ferroptosis, and inflammatory cytokine production in a dose-dependent manner. The F. nucleatum adhesin FadA acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1β, IL-6 and IL-8. Further study showed that FadA could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways. Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F. nucleatum infection. NFκB1 and NFκB2 upregulated after 3 h of F. nucleatum-infection, and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time. Using computational drug repositioning analysis, we predicted and validated that two potential drugs (piperlongumine and fisetin) could attenuate the negative effects of F. nucleatum-infection. Collectively, this study unveils the potential pathogenic mechanisms of F. nucleatum and the host inflammatory response at the early stage of F. nucleatum infection.

Identification of ferroptosis, necroptosis, and pyroptosis-associated genes in periodontitis-affected human periodontal tissue using integrated bioinformatic analysis

Introduction: Periodontitis is a chronic inflammatory oral disease that destroys soft and hard periodontal support tissues. Multiple cell death modes including apoptosis, necroptosis, pyroptosis, and ferroptosis play a crucial role in the pathogenicity of inflammatory diseases. This study aimed to identify genes associated with ferroptosis, necroptosis, and pyroptosis in different cells present in the periodontium of periodontitis patients. Methods: Gingival tissues' mRNA sequencing dataset GSE173078 of 12 healthy control and 12 periodontitis patients' and the microarray dataset GSE10334 of 63 healthy controls and 64 periodontitis patients' were obtained from Gene Expression Omnibus (GEO) database. A total of 910 differentially expressed genes (DEGs) obtained in GSE173078 were intersected with necroptosis, pyroptosis, and ferroptosis-related genes to obtain the differential genes associated with cell death (DCDEGs), and the expression levels of 21 differential genes associated with cell death were verified with dataset GSE10334. Results: Bioinformatic analysis revealed 21 differential genes associated with cell death attributed to ferroptosis, pyroptosis, and necroptosis in periodontitis patients compared with healthy controls. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that 21 differential genes associated with cell death were related to various cellular and immunological pathways including inflammatory responses, necroptosis, and osteoclast differentiation. Additionally, the single-cell RNA (scRNA) sequencing data GSE171213 of 4 healthy controls and 5 periodontitis patients' periodontal tissue was analyzed to obtain cell clustering and cell types attributed to differential genes associated with cell death. We found that among 21 DCDEGs, SLC2A3, FPR2, TREM1, and IL1B were mainly upregulated in neutrophils present in the periodontium of periodontitis patients. Gene overlapping analysis revealed that IL-1B is related to necroptosis and pyroptosis, TREM1 and FPR2 are related to pyroptosis, and SLC2A3 is related to ferroptosis. Finally, we utilized the CIBERSORT algorithm to assess the association between DCDEGs and immune infiltration phenotypes, based on the gene expression profile of GSE10334. The results revealed that the upregulated SLC2A3, FPR2, TREM1, and IL1B were positively correlated with neutrophil infiltration in the periodontium. Discussion: The findings provide upregulated SLC2A3, FPR2, TREM1, and IL1B in neutrophils as a future research direction on the mode and mechanism of cell death in periodontitis and their role in disease pathogenicity.

Regulation of programmed cell death by Brd4

Epigenetic factor Brd4 has emerged as a key regulator of cancer cell proliferation. Targeted inhibition of Brd4 suppresses growth and induces apoptosis of various cancer cells. In addition to apoptosis, Brd4 has also been shown to regulate several other forms of programmed cell death (PCD), including autophagy, necroptosis, pyroptosis, and ferroptosis, with different biological outcomes. PCD plays key roles in development and tissue homeostasis by eliminating unnecessary or detrimental cells. Dysregulation of PCD is associated with various human diseases, including cancer, neurodegenerative and infectious diseases. In this review, we discussed some recent findings on how Brd4 actively regulates different forms of PCD and the therapeutic potentials of targeting Brd4 in PCD-related human diseases. A better understanding of PCD regulation would provide not only new insights into pathophysiological functions of PCD but also provide new avenues for therapy by targeting Brd4-regulated PCD.

Polysaccharide of Atractylodes macrocephala Koidz Alleviates Cyclophosphamide-Induced Thymus Ferroptosis in Gosling

The present study aimed to explore the mechanism by which PAMK alleviates cyclophosphamide (CTX)-induced ferroptosis in thymocytes. One-day-old goslings were divided into four groups (10 goslings/group). The CON and CTX groups were fed a basic diet. The PAMK and CTX + PAMK groups were fed the basic diet mixed with PAMK (400 mg/kg). Moreover, the CTX and CTX + PAMK groups were given a daily injection of 40 mg/kg BW of CTX (at 19, 20, and 21 days of age). On the other hand, the CON and PAMK groups were given 0.5 mL of sterilized saline into the leg muscle (at 19, 20, and 21 days of age). The goslings were fed for 28 days. The ferroptosis pathway was enriched in transcriptome sequencing. Compared to the CON group, the thymus in the CTX group underwent injury, and the mitochondria of thymocytes showed features of ferroptosis. PAMK treatment alleviated ferroptosis in thymocytes and thymus injury, and CTX-induced elevated levels of oxidative stress and iron content restored GPX4 protein expression (p < 0.05) and inhibited the CTX-induced activation of the ferroptosis pathway (p < 0.05). Conclusively, PAMK could reduce thymus injury by alleviating CTX-induced thymocyte ferroptosis in gosling to alleviate the immunosuppression caused by CTX in the organism.

Pyroptosis in inflammatory bone diseases: Molecular insights and targeting strategies

Inflammatory bone diseases include osteoarthritis (OA) and rheumatoid arthritis (RA), which can cause severe bone damage in a chronic inflammation state, putting tremendous pressure on the patients' families and government agencies regarding medical costs. In addition, the complexity of osteoimmunology makes research on these diseases difficult. Hence, it is urgent to determine the potential mechanisms and find effective drugs to target inflammatory bone diseases to reduce the negative effects of these diseases. Recently, pyroptosis, a gasdermin-induced necrotic cell death featuring secretion of pro-inflammatory cytokines and lysis, has become widely known. Based on the effect of pyroptosis on immunity, this process has gradually emerged as a vital component in the etiopathogenesis of inflammatory bone diseases. Herein, we review the characteristics and mechanisms of pyroptosis and then focus on its clinical significance in inflammatory bone diseases. In addition, we summarize the current research progress of drugs targeting pyroptosis to enhance the therapeutic efficacy of inflammatory bone diseases and provide new insights for future directions.

The role of Nrf2 in periodontal disease by regulating lipid peroxidation, inflammation and apoptosis

Nuclear factor E2-related factor 2(Nrf2) is a transcription factor that mainly regulates oxidative stress in the body. It initiates the expression of several downstream antioxidants, anti-inflammatory proteins and detoxification enzymes through the Kelch-like ECH-associating protein 1 (Keap1) -nuclear factor E2-related factor 2(Nrf2) -antioxidant response element (ARE) signaling pathway. Its anti-apoptosis, anti-oxidative stress and anti-inflammatory effects have gradually become the focus of periodontal disease research in recent years. In this paper, the structure and function of Nrf2 pathway and its mechanism of action in the treatment of periodontitis in recent years were analyzed and summarized, so as to further clarify the relationship between Nrf2 pathway and oxidative stress in the occurrence and development of periodontitis, and to provide ideas for the development of new treatment drugs targeting Nrf2 pathway.

Ferroptosis: A New Development Trend in Periodontitis

Periodontitis is a chronic inflammatory disease associated with bacterial biofilm. It is characterized by loss of periodontal support tissue and has long been considered as a "silent disease". Because it is difficult to prevent and has a health impact that can not be ignored, researchers have been focusing on a mechanism-based treatment model. Ferroptosis is an iron-dependent regulatory form of cell death, that directly or indirectly affects glutathione peroxidase through different signaling pathways, resulting in a decrease in cell antioxidant capacity, accumulation of reactive oxygen species and lipid peroxidation, which cause oxidative cell death and tissue damage. Recently, some studies have proven that iron overload, oxidative stress, and lipid peroxidation exist in the process of periodontitis. Based on this, this article reviews the relationship between periodontitis and ferroptosis, in order to provide a theoretical reference for future research on the prevention and treatment of periodontal disease.

Identification of bromodomain-containing proteins prognostic value and expression significance based on a genomic landscape analysis of ovarian serous cystadenocarcinoma

Background

Ovarian serous cystadenocarcinoma (OSC), a common gynecologic tumor, is characterized by high mortality worldwide. Bromodomain (BRD)-containing proteins are a series of evolutionarily conserved proteins that bind to acetylated Lys residues of histones to regulate the transcription of multiple genes. The ectopic expression of BRDs is often observed in multiple cancer types, but the role of BRDs in OSC is still unclear.

Methods

We performed the differential expression, GO enrichment, GSEA, immune infiltration, risk model, subtype classification, stemness feature, DNA alteration, and epigenetic modification analysis for these BRDs based on multiple public databases.

Results

Most BRDs were dysregulated in OSC tissues compared to normal ovary tissues. These BRDs were positively correlated with each other in OSC patients. Gene alteration and epigenetic modification were significant for the dysregulation of BRDs in OSC patients. GO enrichment suggested that BRDs played key roles in histone acetylation, viral carcinogenesis, and transcription coactivator activity. Two molecular subtypes were classified by BRDs for OSC, which were significantly correlated with stemness features, m6A methylation, ferroptosis, drug sensitivity, and immune infiltration. The risk model constructed by LASSO regression with BRDs performed moderately well in prognostic predictions for OSC patients. Moreover, BRPF1 plays a significant role in these BRDs for the development and progression of OSC patients.

Conclusion

BRDs are potential targets and biomarkers for OSC patients, especially BRPF1.

LncRNA HEPFAL accelerates ferroptosis in hepatocellular carcinoma by regulating SLC7A11 ubiquitination

Ferroptosis is a new type of cell death that has been recognized in recent years and is different from apoptosis, autophagy, and necrosis. It is mainly due to cellular iron homeostasis and lipid peroxidation of iron metabolism caused by large accumulation. There is a close correlation between ferroptosis and hepatocellular carcinoma (HCC). This study shows that the expression of the long noncoding RNA HEPFAL was reduced in HCC tissues. We found that lncRNA HEPFAL can promote ferroptosis by reducing the expression of solute carrier family 7 member 11 (SLC7A11) and increasing the levels of lipid reactive oxygen species (ROS) and iron (two surrogate markers of ferroptosis). In addition, we found that lncRNA HEPFAL increases the sensitivity of erastin-induced ferroptosis, which may be related to mTORC1, and lncRNA HEPFAL can promote the ubiquitination of SLC7A11 and reduce the stability of the SLC7A11 protein, resulting in decreased expression. Understanding these mechanisms indicates that lncRNAs related to ferroptosis are essential for the occurrence and treatment of HCC.

Tocopherol attenuates the oxidative stress of BMSCs by inhibiting ferroptosis through the PI3k/AKT/mTOR pathway

Oxidative stress can induce bone tissue damage and the occurrence of multiple diseases. As a type of traditional medicine, tocopherol has been reported to have a strong antioxidant effect and contributes to osteogenic differentiation. The purpose of this study was to investigate the protective effect of tocopherol on the oxidative stress of rat bone marrow-derived mesenchymal stem cells (BMSCs) and the underlying mechanisms. By establishing an oxidative stress model in vitro, the cell counting kit-8 (CCK-8), reactive oxygen species (ROS) analysis, Western blot (WB), real-time PCR (RT-PCR), alkaline phosphatase (ALP) staining, and Alizarin Red staining (ARS) evaluated the effects of tocopherol on the cell viability, intracellular ROS levels, and osteogenic differentiation in BMSCs. In addition, ferroptosis-related markers were examined via Western blot, RT-PCR, and Mito-FerroGreen. Eventually, the PI3K/AKT/mTOR signaling pathway was explored. We found that tocopherol significantly maintained the cell viability, reduced intracellular ROS levels, upregulated the levels of anti-oxidative genes, promoted the levels of osteogenic-related proteins, and the mRNA of BMSCs stimulated by H₂O₂. More importantly, tocopherol inhibited ferroptosis and upregulated the phosphorylation levels of PI3K, AKT, and mTOR of BMSCs upon H₂O₂ stimulation. In summary, tocopherol protected BMSCs from oxidative stress damage via the inhibition of ferroptosis through the PI3K/AKT/mTOR pathway.