FOXO family isoforms

The dual missions of FoxO3a in inflammatory diseases: Regulation of antioxidant enzymes and involvement in programmed cell death

The transcription factor FoxO3a plays a crucial role in the process of cells adapting to various stress conditions. Multiple post - translational modifications and epigenetic mechanisms work together to precisely regulate the activity of FoxO3a, influencing its subcellular localization, stability, interactions with other proteins, DNA - binding affinity, and transcriptional regulatory capacity. Under different chemical signal stimuli and subcellular environments, the activation of FoxO3a triggered by oxidative stress can initiate diverse transcriptional programs, which are essential for the body to resist oxidative damage. In the development and progression of inflammatory diseases, FoxO3a exerts an important function by regulating the expression levels of antioxidant enzymes and participating in key physiological processes such as programmed cell death. This article comprehensively reviews the structural characteristics, mechanism of action of FoxO3a, as well as its functions in regulating antioxidant enzymes and programmed cell death. The aim is to deeply explore the potential of FoxO3a as a potential therapeutic target for preventing and treating damages such as inflammatory diseases caused by cellular stress.

FOXO6: A unique transcription factor in disease regulation and therapeutic potential

FOXO6, a unique member of the Forkhead box O (FOXO) transcription factor family, has emerged as a pivotal regulator in various physiological and pathological processes, including apoptosis, oxidative stress, autophagy, cell cycle control, and inflammation. Unlike other FOXO proteins, FOXO6 exhibits distinct regulatory mechanisms, particularly its inability to undergo classical nucleocytoplasmic shuttling. These unique properties suggest that FOXO6 may function through alternative pathways, positioning it as a novel research target. This review provides the first comprehensive review of FOXO6's biological functions and its roles in the progression of multiple diseases, such as cancer, metabolic disorders, neurodegenerative conditions, and cardiovascular dysfunction. We highlight FOXO6's interaction with critical signaling pathways, including PI3K/Akt, PPARγ, and TXNIP, and discuss its contributions to tumor progression, glucose and lipid metabolism, oxidative stress, and neuronal degeneration. Moreover, FOXO6's potential as a therapeutic target is explored, with particular emphasis on its ability to modulate drug resistance and its implications for disease treatment. Despite its promising therapeutic potential, the development of FOXO6-targeted therapies remains challenging due to overlapping functions within the FOXO family and the context-dependent nature of FOXO6's regulatory roles. This review underscores the need for further experimental and clinical studies to elucidate the molecular mechanisms underlying FOXO6's functions and to validate its application in disease prevention and treatment. By systematically analyzing current research, this review aims to provide a foundational reference for future studies on FOXO6, paving the way for novel therapeutic strategies targeting this unique transcription factor.

Gene expression profile in ulcerative colitis patients: FOXO4, ALDOB, SLC26A3, SOD2 genes as potential biomarkers

BACKGROUND

Ulcerative colitis (UC) is a complex, chronic inflammatory disease that primarily impacts the colon mucosa. One of the key pathological contributors to the development and progression of inflammatory bowel disease (IBD) is oxidative stress, which results in reactive oxygen species (ROS)-induced mucosal damage. This stress leads to dysfunction of the intestinal barrier.

OBJECTIVES

The purpose of this study is to examine the expression levels of genes involved in various inflammatory pathways, including autophagy, unfolded protein response (UPR), ubiquitination, metabolic pathways, and immune responses in the colon mucosa of patients with UC.

MATERIAL AND METHODS

Patients diagnosed with UC at Çukurova University, Balcalı Hospital, Gastroenterology Department between December 2023 and January 2024 were included in this prospective study. A total of 40 participants were included in the study: 27 ulcerative colitis patients and 13 controls. To isolate high-quality RNA, colon biopsy material obtained during colonoscopy was immediately placed in stabilization solution and stored at - 80 degrees Celsius. The relative quantification of target gene mRNA was determined using a Light Cycler. Subsequently, differences in gene expression between patients and the control group were evaluated using the Mann-Whitney U and Kruskal-Wallis tests.

RESULTS

In our study, FOXO4 gene expression increased in UC patients during both active and remission phases compared to the control group. The high expression of this gene is associated with its role in inflammation and cell death processes. Additionally, the high expression of ALDOB and SLC26A genes is linked to increased inflammation and energy demand. Lastly, the elevated expression of the SOD2 gene can be considered a response to oxidative stress-related inflammatory processes in the disease.

CONCLUSION

These findings propose that these genes could serve as potential biomarkers for genomic identification and understanding the pathogenesis of UC.

Signaling pathways and targeted therapies in Ewing sarcoma

Ewing sarcoma, the second most prevalent malignant bone tumor with potential occurrence in soft tissues, exhibits a high level of aggressiveness, primarily afflicting children and adolescents. It is characterized by fusion proteins arising from chromosomal translocations. The fusion proteins induce aberrations in multiple signaling pathways and molecules, constituting a key event in oncogenic transformation. While diagnostic and therapeutic modalities have advanced in recent decades and multimodal treatments, including surgery, radiotherapy, and chemotherapy, have significantly improved survival of patients with localized tumors, patients with metastatic tumors continue to face poor prognoses. There persists a pressing need for novel alternative treatments, yet the translation of our understanding of Ewing sarcoma pathogenesis into improved clinical outcomes remains a critical challenge. Here, we provide a comprehensive review of Ewing sarcoma, including fusion proteins, various signaling pathways, pivotal pathogenetic molecules implicated in its development, and associated targeted therapies and immunotherapies. We summarize past endeavors, current advancements, and deliberate on limitations and future research directions. It is envisaged that this review will furnish novel insights into prospective treatment avenues for Ewing sarcoma.

The Genetic and Epigenetic Arms of Human Ageing and Longevity

This proposed review aims to shed light on the major genetic and epigenetic contributions to the ageing process and longevity of individuals. In this context, we summarize the state of knowledge on the most important longevity and ageing genetic variants, and their interactions with the environment, in achieving a healthy lifespan. We also explore the contribution of lifestyle and the influence of non-heritable environmental factors on ageing (i.e., epigenetics). Accordingly, we discuss the role of inflammageing as one of the major targets to overcome morbidity and mortality in older people for the maintenance of healthy ageing. This more integrated view of longevity will display not only the underlying mechanisms at play but also invites the reader to rethink both our ageing process and our attitudes toward age.

Identification of Small-Molecule Modulators of FOXO3 Through Virtual Screening

FOXO3 is integral in regulating numerous genes involved in critical cellular processes such as apoptosis, oxidative damage protection, cell growth, and cancer. Consequently, modulating FOXO3 activity holds significant potential for applications in cancer treatment and cellular aging. A promising approach involves identifying small-molecule modulators that can either enhance or inhibit FOXO3's DNA-binding capability. This paper details a virtual screening protocol aimed at discovering such modulators. Utilizing the crystal structures of FOXO3 in both its free and DNA-bound forms, we pinpoint potential binding sites that may disrupt or facilitate the DNA-FOXO3 interaction. A comprehensive virtual screening of a small-molecule compound library is conducted using AutoDock Vina software. The highest-ranking hits for each site are carefully selected and analyzed to determine their binding modes. This protocol paves the way for identifying novel modulators of FOXO3, offering therapeutic avenues in cancer and aging-related research.

Effect of Acetyl tributyl citrate on bone metabolism based on network toxicology and molecular docking technology

This study aims to elucidate the intricate effects of Acetyl tributyl citrate (ATBC) on bone metabolism, disentangling the underlying molecular mechanisms that govern the impact of environmental contaminants on disease processes. Leveraging the exhaustive exploration of databases such as ChEMBL, STITCH, GeneCards, and OMIM, we have identified a comprehensive list of 164 potential targets intimately associated with both ATBC and bone metabolism. Following rigorous refinement using the STRING platform and Cytoscape software, we pinpointed ten core targets, encompassing KDM1A, EP300, HDAC2, EHMT2, DNMT1, and several others. In-depth Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, conducted within the Metascape database, revealed that the core targets of ATBC's influence on bone metabolism are predominantly concentrated within vital signaling cascades, including thyroid hormone signaling, FOXO signaling, glucagon signaling, AMPK signaling, insulin signaling, adipocytokine signaling, and Notch signaling pathways. Additionally, molecular docking simulations performed with AutoDock software confirmed the robust binding interactions between ATBC and these core targets, reinforcing our understanding of their interactions. To explore the cellular impact of ATBC, we performed in vitro experiments using osteoblasts (MC3T3-E1) exposed to relevant concentrations. Our findings revealed that low-dose ATBC (100 μM) significantly impaired cell proliferation and migration. Concurrently, we observed a downregulation in the transcriptional expression of key epigenetic regulators (KDM1A, EP300, HDAC2), suggesting that ATBC can disrupt bone metabolism at the cellular level. Collectively, our findings provide a theoretical scaffold for comprehending the intricate molecular mechanisms mediating ATBC's effects on bone metabolism, and paves the way for the development of preventive and therapeutic strategies against orthopedic disorders that may arise from exposure to plastic products containing ATBC or excessive ATBC environments.

Phosphorylation of FOXO Proteins as a Key Mechanism to Regulate Their Activity

Phosphorylation of FOXO transcription factors is one of the key mechanisms involved in the regulation of the activity, nucleo-cytosolic shuttling, and stability of this family of proteins. Here we describe several experimental approaches allowing analysis of changes in the phosphorylation of these proteins upon exposure to different stimuli.

Multiplexed Dual-Color Fluorescence-Based Distinction Between Nuclear Trapping and Translocation of FOXO3

FOXO3 is a transcription factor that mainly exerts its functions in the cell nucleus. The amino acid sequence of FOXO3 contains a nuclear localization sequence (NLS) and a nuclear export sequence (NES) allowing for nuclear/cytoplasmic shuttling that plays an important role in regulating FOXO3 activity. Nuclear accumulation of FOXO3 proteins can be the result of translocation to the nucleus triggered by upstream regulatory input or trapping of FOXO3 within the nucleus through the inhibition of its nuclear export via the receptor CRM1. In order to distinguish these two modes of FOXO3 activation, we have generated a multiplexed assay. The development of this platform includes a reporter cell line that monitors CRM1 activity by using RFP-labeled HIV-1 Rev. protein with a strong heterologous NES. Simultaneously, the intracellular localization of FOXO3 can be monitored by a second cell line stably expressing GFP-FOXO3. Here we describe a detailed protocol on how to co-culture these reporter cell lines and use them to interrogate compound-induced FOXO3 activation in order to understand the mode of action.

Role of the Transcription Factor FoxO in Type 2 Diabetes and Its Complications

FoxO proteins represent a subfamily of the forkhead box family (Fox) superfamily of proteins. It is involved in cell proliferation, differentiation, oxidative stress, apoptosis as well as tumors and metabolic disorders by regulating cellular functions. This paper aims to summarize the role of the transcription factor FoxO in type 2 diabetes and its complications, which may add to the potential of FoxO as a therapeutic target for future research. The transcription factor FoxO is expressed in various tissues and participates in various bodily functions including cell proliferation, differentiation, apoptosis, tumor therapy, and metabolic processes, playing a crucial role in the human body. FoxO plays a positive role in attenuating oxidative stress, inflammation, and metabolic disorders, which are the main causes of type 2 diabetes and its complications. FoxO plays an important role in the regulation of type 2 diabetes and its complications, and more precise targeting studies of FoxO will help to prevent, regulate, and treat diabetes-related diseases.

FOXO Transcription Factors: A Brief Overview

Forkhead box O (FOXO) transcription factors constitute a mammalian family of proteins, comprising FOXO1, FOXO3, FOXO4, and FOXO6. Originally recognized as downstream regulators within the insulin pathway, FOXO factors exhibit the ability to bind to diverse target gene promoters, thereby governing crucial facets of cellular homeostasis. These encompass cellular energy generation, resilience against oxidative stress, and the modulation of cell viability and proliferation. The dysregulation of FOXO proteins has been established as pivotal in metabolic disorders, human longevity, and the inhibition of tumorigenesis. Notably subject to posttranslational modifications for regulation, FOXO inactivation predominantly arises from excessive activation of their upstream modifying enzymes, presenting a plethora of potential avenues for pharmaceutical reinstatement of FOXO activity.

Immunocytochemistry-Based Detection of FOXO Isoforms in Human Cancer and Fibroblasts

In mammals, the FOXO protein family consists of four distinct isoforms: FOXO1, FOXO3, FOXO4, and FOXO6. These isoforms are key players in a wide spectrum of physiological and pathological processes, including context-specific tumor suppression. FOXO3, in particular, has emerged as a gene associated with extraordinary human longevity. While these four FOXO isoforms share common biological functions, the mechanisms underlying their overlapping and distinct roles remain less understood. It is believed that intrinsic properties and context-dependent factors contribute to isoform-specific and nonredundant FOXO functions. One promising avenue for unraveling the commonalities and specificities of these proteins involves characterizing their expression patterns in specific cell types and their activation in response to different stimuli. To facilitate this, we have developed immunocytochemistry methods capable of detecting FOXO isoforms in a highly specific manner within various human cancer cell types and fibroblasts. Importantly, this approach enables the visualization of endogenous FOXO proteins as they translocate into the cell nucleus in response to different stimuli. In this article, we present a comprehensive guide to these procedures, offering valuable insights into the distinct roles of FOXO isoforms in cellular function.

NMR 1H, 13C, 15N backbone resonance assignments of 14-3-3ζ binding region of human FOXO3a (residues 1-284)

In tumors, mutation in Ras proteins stimulates a signaling cascade through phosphorylation. Downstream of the cascade, many transcription and translation factors are up- or down-regulated by phosphorylation, leading to cancer progression. This phosphorylation cascade is sustained by 14-3-3ζ protein. 14-3-3ζ binds to its client proteins that are Ser/Thr-phosphorylated and prevents their dephosphorylation. One of those transcription factors is FOXO3a, whose transcriptional activity is suppressed in the phosphorylation cascade. FOXO3a binds to specific DNA sequences and activates the transcription of apoptosis-related proteins. In cancer cells, however, FOXO3a is phosphorylated, bound to 14-3-3ζ, and dissociated from the DNA, resulting in FOXO3a inactivation. To elucidate the mechanism of FOXO3a inactivation by the 14-3-3ζ binding, we aim to perform NMR analysis of the interaction between 14-3-3ζ and di-phosphorylated FOXO3a residues 1-284 (dpFOXO3a). Here, we report the backbone resonance assignments of dpFOXO3a, which are transferred from those of the N-terminal domain (NTD) and the DNA-binding domain (DBD) of dpFOXO3a.

c-Myc and FOXO3a-The Everlasting Decision Between Neural Regeneration and Degeneration

The transcription factors c-Myc and FoxO3a play significant roles in neurodegenerative processes, yet their interaction in neurological disorders remains largely unexplored. In contrast, much of the available information about their relationship comes from cancer research. While it is well-established that FoxO3a inhibits c-Myc activity, this interaction represents only a basic understanding of a far more complex dynamic, which includes exceptions under specific conditions and the involvement of additional regulatory factors. Given the critical need to address this gap for the treatment and prevention of neurodegenerative disorders, this review consolidates current knowledge on the joint roles of these two factors in neuropathology. It also highlights their conformational flexibility, post-translational modifications, and outlines potential directions for future research.

RNAi-Mediated FoxO Silencing Inhibits Reproduction in Locusta migratoria

FoxO is a downstream target gene of cellular nutrient and growth factors, oxidative stress responses, and insulin signaling pathways. It play a crucial role in insect growth, development, and reproduction. Locusta migratoria is a significant agricultural pest; therefore, the identification of novel control targets for its management is of significant importance. After injecting dsRNA to interfere with FoxO expression, we observed changes in the reproduction-related gene expression and ovary development through RT-qPCR and morphological observation. Simultaneously, the trehalose and glycogen contents were measured following RNAi. The results demonstrate that interference with FoxO significantly downregulates key genes in the Hippo pathway and Notch gene expression. In terms of carbohydrate metabolism, the trehalose content decreases significantly while the glycogen content increases markedly after FoxO silencing. Additionally, FoxO silencing considerably inhibits reproductive-related gene expression, resulting in delayed ovarian development. These findings indicate that FoxO regulates L. migratoria reproduction through the Hippo signaling pathway: when impaired, the reproductive capacity function declines. In addition, FoxO-mediated energy mobilization is involved in the regulation of egg production. These results indicate that the RNAi of FoxO may be a useful control strategy against L. migratoria.

Incretin-Based Therapies: A Promising Approach for Modulating Oxidative Stress and Insulin Resistance in Sarcopenia

BACKGROUND

Recent studies have linked sarcopenia development to the hallmarks of diabetes, oxidative stress, and insulin resistance. The anti-oxidant and insulin sensitivityenhancing effects of incretin-based therapies may provide a promising option for the treatment of sarcopenia. This review aimed to unveil the role of oxidative stress and insulin resistance in the pathogenesis of sarcopenia and explore the potential benefits of incretin-based therapies in individuals with sarcopenia.

METHODS

PubMed, the Cochrane Library, and Google Scholar databases were searched by applying keywords relevant to the main topic, to identify articles that met our selection criteria.

RESULTS

Incretin-based therapies manifested anti-oxidant effects by increasing the anti-oxidant defense system and decreasing free radical generation or by indirectly minimizing glucotoxicity, which was mainly achieved by improving insulin signaling and glucose homeostasis. Likewise, these drugs exhibit insulin-sensitizing activities by increasing insulin secretion, transduction, and β-cell function or by reducing inflammation and lipotoxicity.

CONCLUSIONS

Incretin-based therapies, as modulators of oxidation and insulin resistance, may target the main pathophysiological factors of sarcopenia, thus providing a promising strategy for the treatment of this disease.

Blockade of forkhead box protein O1 signaling alleviates primary sclerosing cholangitis-induced sarcopenia in mice model

AIMS

Primary sclerosing cholangitis (PSC) is a cholestatic liver disease that affects the hepatic bile ducts, leading to hepatic inflammation and fibrosis. PSC can also impact skeletal muscle through the muscle-liver axis, resulting in sarcopenia, a complication characterized by a generalized loss of muscle mass and strength. The underlying mechanisms and therapy of PSC-induced sarcopenia are not well understood, but one potential regulator is the transcription factor forkhead box protein O1 (FOXO1), which is involved in the ubiquitin proteasome system. Thus, the aim of this study is to assess the pharmacological potential of FOXO1 inhibition for treating PSC-induced sarcopenia.

MATERIALS AND METHODS

To establish diet-induced PSC model, we provided mice with a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet for 4 weeks. Mice were intramuscularly injected with AS1842856 (AS), a FOXO1 inhibitor, at a dose of 3.5 mg/kg twice a week for last two weeks. C2C12 myotubes with cholic acid (CA) or deoxycholic acid (DCA) were treated with AS.

KEY FINDINGS

We observed a decrease in muscle size and performance in DDC-fed mice with upregulated expression of FOXO1 and E3 ligases such as ATROGIN1 and MuRF1. We found that myotube diameter and MyHC protein level were decreased by CA or DCA in C2C12 myotubes, but treatment of AS reversed these reductions. We observed that intramuscular injection of AS effectively mitigates DDC diet-induced sarcopenia in a rodent PSC model.

SIGNIFICANCE

Our study suggests that a FOXO1 inhibitor could be a potential leading therapeutic drug for relieving PSC-induced sarcopenia.

Micellar curcumol for maintenance therapy of ovarian cancer by activating the FOXO3a

Maintenance therapy (MT) for ovarian cancer (OC) is crucial for preventing disease relapse. Curcumol shows effective anti-OC ability and low-toxicity to the normal ovarian epithelial cells, however, its bioavailability is low. Herein, micellar loaded curcumol (MC) was prepared and the anti-tumor ability of MC were performed on OC cells. The results indicated that the IC50 values of MC in two kinds of OC cells were 37.69 ± 2.43 and 28.54 ± 1.58 μg/mL, respectively. Mechanistically, curcumol could interact with the AKTThr308 site, inhibiting the phosphorylation of FOXO3a, which promoted FOXO3a nuclear locating and recruited it to the PERK promoter, activating the ERS induced apoptosis pathway. Moreover, MC inhibited the growth of SKOV3 cells on tumor-bearing nude mice and the DiR-labeled MC could quickly accumulate in the tumor region. MC provides great feasibility to achieve efficient MT for OC based on the nanoplatforms of active ingredients from natural products.

[Tongsai Granules inhibit autophagy and macrophage-mediated inflammatory response to improve acute exacerbations of chronic obstructive pulmonary disease in rats]

OBJECTIVE

To investigate the inhibitory effect of Tongsai Granules (TSG) on macrophage-mediated inflammatory response to alleviate acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in rats and explore the underlying mechanism.

METHODS

Twenty-four rats were divided into control group, AECOPD model group, TSG treatment group, and moxifloxacin+salbutamol (MXF+STL) treatment group. In the rat models of COPD, AECOPD was induced by nasal instillation of Klebsiella pneumoniae on day 3 of week 9 after modeling, and saline, TSG or MXF+STL were administered via gavage on days 1 and 2 and days 4 to 7 of week 9. After the treatments, lung tissues were collected for examining for pathologies and expressions of inflammatory markers, MMP2, and MMP9. In cultured macrophage MH-S cells with LPS stimulation, the effect of TSG-medicated serum on IL-1β, IL-6, TNF-α, COX-2, and iNOS expressions and phosphorylation levels of p38, p-p62, LC3, FoxO3a, and mTOR were evaluated.

RESULTS

TSG significantly improved lung pathologies and lung function in AECOPD rats by reducing bronchial wall thickness and mean alveolar linear intercept, increasing alveolar numbers, and reducing pulmonary expression of IL-1β, IL-6, TNF- α, MMP2 and MMP9. In MH-S cells, TSG significantly suppressed LPS-induced expressions of inflammatory cytokines, COX-2 and iNOS. Serum pharmacology coupled with network pharmacology identified 10 chemical components in TSG-medicated serum, and functional analysis of their 466 targets suggested that the therapeutic effect of TSG on AECOPD was mediated primarily by luteolin and quercetin, which regulate the MAPK, mTOR, FoxO, and autophagy pathways. In MH-S cells, luteolin significantly inhibited LPS-induced inflammatory responses and expressions of p-p38, FoxO3a, mTOR, p-p62 and LC3.

CONCLUSION

TSG reduces macrophage-mediated inflammatory responses to alleviate AECOPD in rats possibly by modulating p38, mTOR, and FoxO3a pathways and inhibiting autophagy.

FoxO1-Overexpressed Small Extracellular Vesicles Derived from hPDLSCs Promote Periodontal Tissue Regeneration by Reducing Mitochondrial Dysfunction to Regulate Osteogenesis and Inflammation

Purpose

Periodontitis is a chronic infectious disease characterized by progressive inflammation and alveolar bone loss. Forkhead box O1 (FoxO1), an important regulator, plays a crucial role in maintaining bone homeostasis and regulating macrophage energy metabolism and osteogenic differentiation of mesenchymal stem cells (MSCs). In this study, FoxO1 was overexpressed into small extracellular vesicles (sEV) using engineering technology, and effects of FoxO1-overexpressed sEV on periodontal tissue regeneration as well as the underlying mechanisms were investigated.

Methods

Human periodontal ligament stem cell (hPDLSCs)-derived sEV (hPDLSCs-sEV) were isolated using ultracentrifugation. They were then characterized using transmission electron microscopy, Nanosight, and Western blotting analyses. hPDLSCs were treated with hPDLSCs-sEV in vitro after stimulation with lipopolysaccharide, and osteogenesis was evaluated. The effect of hPDLSCs-sEV on the polarization phenotype of THP-1 macrophages was also evaluated. In addition, we measured the reactive oxygen species (ROS) levels, adenosine triphosphate (ATP) production, mitochondrial characteristics, and metabolism of hPDLSCs and THP-1 cells. Experimental periodontitis was established in vivo in mice. HPDLSCs-sEV or phosphate-buffered saline (PBS) were injected into periodontal tissues for four weeks, and the maxillae were collected and assessed by micro-computed tomography, histological staining, and small animal in vivo imaging.

Results

In vitro, FoxO1-overexpressed sEV promoted osteogenic differentiation of hPDLSCs in the inflammatory environment and polarized THP-1 cells from the M1 phenotype to the M2 phenotype. Furthermore, FoxO1-overexpressed sEV regulated the ROS level, ATP production, mitochondrial characteristics, and metabolism of hPDLSCs and THP-1 cells in the inflammatory environment. In the in vivo analyses, FoxO1-overexpressed sEV effectively promoted bone formation and inhibited inflammation.

Conclusion

FoxO1-overexpressed sEV can regulate osteogenesis and immunomodulation. The ability of FoxO1-overexpressed sEV to regulate inflammation and osteogenesis can pave the way for the establishment of a therapeutic approach for periodontitis.

Anti-Inflammatory Role of the Klotho Protein and Relevance to Aging

The α-Klotho protein (hereafter Klotho) is an obligate coreceptor for fibroblast growth factor 23 (FGF23). It is produced in the kidneys, brain and other sites. Klotho insufficiency causes hyperphosphatemia and other anomalies. Importantly, it is associated with chronic pathologies (often age-related) that have an inflammatory component. This includes atherosclerosis, diabetes and Alzheimer's disease. Its mode of action in these diseases is not well understood, but it inhibits or regulates multiple major pathways. Klotho has a membrane form and a soluble form (s-Klotho). Cytosolic Klotho is postulated but not well characterized. s-Klotho has endocrine properties that are incompletely elucidated. It binds to the FGF receptor 1c (FGFR1c) that is widely expressed (including endothelial cells). It also attaches to soluble FGF23, and FGF23/Klotho binds to FGFRs. Thus, s-Klotho might be a roaming FGF23 coreceptor, but it has other functions. Notably, Klotho (cell-bound or soluble) counteracts inflammation and appears to mitigate related aging (inflammaging). It inhibits NF-κB and the NLRP3 inflammasome. This inflammasome requires priming by NF-κB and produces active IL-1β, membrane pores and cell death (pyroptosis). In accord, Klotho countered inflammation and cell injury induced by toxins, damage-associated molecular patterns (DAMPs), cytokines, and reactive oxygen species (ROS). s-Klotho also blocks the TGF-β receptor and Wnt ligands, which lessens fibrotic disease. Low Klotho is associated with loss of muscle mass (sarcopenia), as occurs in aging and chronic diseases. s-Klotho counters the inhibitory effects of myostatin and TGF-β on muscle, reduces inflammation, and improves muscle repair following injury. The inhibition of TGF-β and other factors may also be protective in diabetic retinopathy and age-related macular degeneration (AMD). This review examines Klotho functions especially as related to inflammation and potential applications.

Gene, Protein, and in Silico Analyses of FoxO, an Evolutionary Conserved Transcription Factor in the Sea Urchin Paracentrotus lividus

FoxO is a member of the evolutionary conserved family of transcription factors containing a Forkhead box, involved in many signaling pathways of physiological and pathological processes. In mammals, mutations or dysfunctions of the FoxO gene have been implicated in diverse diseases. FoxO homologs have been found in some invertebrates, including echinoderms. We have isolated the FoxO cDNA from the sea urchin Paracentrotus lividus (Pl-foxo) and characterized the corresponding gene and mRNA. In silico studies showed that secondary and tertiary structures of Pl-foxo protein corresponded to the vertebrate FoxO3 isoform, with highly conserved regions, especially in the DNA-binding domain. A phylogenetic analysis compared the Pl-foxo deduced protein with proteins from different animal species and confirmed its evolutionary conservation between vertebrates and invertebrates. The increased expression of Pl-foxo mRNA following the inhibition of the PI3K signaling pathway paralleled the upregulation of Pl-foxo target genes involved in apoptosis or cell-cycle arrest events (BI-1, Bax, MnSod). In silico studies comparing molecular data from sea urchins and other organisms predicted a network of Pl-foxo protein-protein interactions, as well as identified potential miRNAs involved in Pl-foxo gene regulation. Our data may provide new perspectives on the knowledge of the signaling pathways underlying sea urchin development.

Forkhead box O1 transcription factor; a therapeutic target for diabetic cardiomyopathy

Cardiovascular disease including diabetic cardiomyopathy (DbCM) represents the leading cause of death in people with diabetes. DbCM is defined as ventricular dysfunction in the absence of underlying vascular diseases and/or hypertension. The known molecular mediators of DbCM are multifactorial, including but not limited to insulin resistance, altered energy metabolism, lipotoxicity, endothelial dysfunction, oxidative stress, apoptosis, and autophagy. FoxO1, a prominent member of forkhead box O transcription factors, is involved in regulating various cellular processes in different tissues. Altered FoxO1 expression and activity have been associated with cardiovascular diseases in diabetic subjects. Herein we provide an overview of the role of FoxO1 in various molecular mediators related to DbCM, such as altered energy metabolism, lipotoxicity, oxidative stress, and cell death. Furthermore, we provide valuable insights into its therapeutic potential by targeting these perturbations to alleviate cardiomyopathy in settings of type 1 and type 2 diabetes.

SIRT1 signaling pathways in sarcopenia: Novel mechanisms and potential therapeutic targets

Sarcopenia is an aging-related skeletal disease characterized by decreased muscle mass, strength, and physical function, severely affecting the quality of life (QoL) of the elderly population. Sirtuin 1 (SIRT1), as a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases, has been reported to participate in various aging-related signaling pathways and exert protective effect on many human diseases. SIRT1 functioned as an important role in the occurrence and progression of sarcopenia through regulating key pathways related to protein homeostasis, apoptosis, mitochondrial dysfunction, insulin resistance and autophagy in skeletal muscle, including SIRT1/Forkhead Box O (FoxO), AMP-activated protein kinase (AMPK)/SIRT1/nuclear factor κB (NF-κB), SIRT1/p53, AMPK/SIRT1/peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and SIRT1/live kinase B1 (LKB1)/AMPK pathways. However, the specific mechanisms of these processes have not been fully illuminated. Currently, several SIRT1-mediated interventions on sarcopenia have been preliminarily developed, such as SIRT1 activator polyphenolic compounds, exercising and calorie restriction. In this review, we summarized the predominant mechanisms of SIRT1 involved in sarcopenia and therapeutic modalities targeting the SIRT1 signaling pathways for the prevention and prognosis of sarcopenia.

Longevity factor FOXO3a: A potential therapeutic target for age-related ocular diseases

The forkhead box protein O3 (FOXO3a) belongs to the subgroup O of the forkhead transcription factor family and plays an important role in regulating the aging process by participating in the regulation of various life processes, including cell cycle arrest, apoptosis, autophagy, oxidative stress, and DNA repair. The eye is an organ that is affected by aging earlier. However, the functional role and potential clinical applications of FOXO3a in age-related eye diseases have not received widespread attention and lacked comprehensive and clear clarification. In this review, we demonstrated the relationship between FOXO3a and visual system health, summarized the functional roles of FOXO3a in various eye diseases, and potential ocular-related therapies and drugs targeting FOXO3a in visual system diseases through a review and summary of relevant literature. This review indicates that FOXO3a is an important factor in maintaining the normal function of various tissues in the eye, and is closely related to the occurrence and development of ophthalmic-related diseases. Based on its vital role in the normal function of the visual system, FOXO3a has potential clinical application value in related ophthalmic diseases. At present, multiple molecules and drugs targeting FOXO3a have been reported to have the potential for the treatment of related ophthalmic diseases, but further clinical trials are needed. In conclusion, this review can facilitate us to grasp the role of FOXO3a in the visual system and provide new views and bases for the treatment strategy research of age-related eye diseases.

Functional properties of aged hypothalamic cells

The hypothalamus, in addition to controlling the main body's vital functions, is also involved in aging regulation. The aging process in the hypothalamus is accompanied by disturbed intracellular pathways, including Ca2+ signaling and neuronal excitability in the brain. Intrinsic electrophysiological properties of individual neurons and synaptic transmission between cells is disrupted in the central nervous system of old animals. However, changes in neuronal excitability and excitation/inhibition balance with aging are specific to the type of neurons, brain region, and species. Glia-neuron interactions play a significant role in the brain and undergo remodeling accompanied by advanced loss of function with aging. In the current review, I have summarized the current understanding of the changes in the brain and especially in the hypothalamus with aging.

Forkhead box O1 in metabolic dysfunction-associated fatty liver disease: molecular mechanisms and drug research

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a chronic liver disease that progresses from hepatic steatosis to non-alcoholic steatohepatitis, cirrhosis, and liver cancer, posing a huge burden on human health. Existing research has confirmed that forkhead box O1 (FOXO1), as a member of the FOXO transcription factor family, is upregulated in MAFLD. Its activity is closely related to nuclear-cytoplasmic shuttling and various post-translational modifications including phosphorylation, acetylation, and methylation. FOXO1 mediates the progression of MAFLD by regulating glucose metabolism, lipid metabolism, insulin resistance, oxidative stress, hepatic fibrosis, hepatocyte autophagy, apoptosis, and immune inflammation. This article elaborates on the regulatory role of FOXO1 in MAFLD, providing a summary and new insights for the current status of drug research and targeted therapies for MAFLD.

Interferon-Alpha Induces Psoriatic Inflammation in Mice by Phosphorylating FOXO3

Psoriasis is a chronic, immune-mediated inflammatory skin disease characterized by epidermal thickening and inflammatory cell infiltration. Excessive proliferation of keratinocytes and resistance to apoptosis lead to thickening of the epidermis. Plasmacytoid dendritic cells are involved in the occurrence of psoriasis mainly by secreting interferon-alpha (IFN-α). IFN-α is a glycoprotein with antiviral, antitumor, and immunomodulatory effects, but its role in psoriasis remains unclear. In this investigation, a mild psoriatic phenotype was observed in mice upon topical application of IFN-α cream, and the inflammation was exacerbated when combined with imiquimod (IMQ). Immunohistochemical analyses demonstrated that IFN-α induces psoriatic inflammation in mice by stimulating phosphorylation of forkhead box O3, consistent with the involvement of this protein in cell proliferation, apoptosis, and inflammation. Our results suggested that topical IFN-α caused psoriatic inflammation and that the psoriatic inflammation was exacerbated by the combination of IFN-α and IMQ, possibly due to the dysfunction of forkhead box O3.

Immunohistochemical Investigation into Protein Expression Patterns of FOXO4, IRF8 and LEF1 in Canine Osteosarcoma

Osteosarcoma (OSA) is the most common type of primary bone malignancy in people and dogs. Our previous molecular comparisons of canine OSA against healthy bone resulted in the identification of differentially expressed protein-expressing genes (forkhead box protein O4 (FOXO4), interferon regulatory factor 8 (IRF8), and lymphoid enhancer binding factor 1 (LEF1)). Immunohistochemistry (IHC) and H-scoring provided semi-quantitative assessment of nuclear and cytoplasmic staining alongside qualitative data to contextualise staining (n = 26 patients). FOXO4 was expressed predominantly in the cytoplasm with significantly lower nuclear H-scores. IRF8 H-scores ranged from 0 to 3 throughout the cohort in the nucleus and cytoplasm. LEF1 was expressed in all patients with significantly lower cytoplasmic staining compared to nuclear. No sex or anatomical location differences were observed. While reduced levels of FOXO4 might indicate malignancy, the weak or absent protein expression limits its primary use as diagnostic tumour marker. IRF8 and LEF1 have more potential for prognostic and diagnostic uses and facilitate further understanding of their roles within their respective molecular pathways, including Wnt/beta-catenin/LEF1 signalling and differential regulation of tumour suppressor genes. Deeper understanding of the mechanisms involved in OSA are essential contributions towards the development of novel diagnostic, prognostic, and treatment options in human and veterinary medicine contexts.