Chemokine CXCL12 induces binding of ferritin heavy chain to the chemokine receptor CXCR4, alters CXCR4 signaling, and induces phosphorylation and nuclear translocation of ferritin heavy chain

Causal Association of Iron Status With Functional Outcome After Ischemic Stroke

BACKGROUND

Iron status has been associated with functional outcomes after ischemic stroke (IS). Nonetheless, this association may be affected by confounders. We perform Mendelian randomization to clarify the causal association between iron status and functional outcome after IS.

METHODS

We obtained summary-level statistics related to iron status biomarkers from a meta-analysis of a gene-wide association study conducted by the Genetics of Iron Status Consortium, which included 11 discovery cohorts and 8 replication cohorts. We also took genetic variants related to 4 biomarkers of iron status from combining gene-wide association study results of Iceland, the United Kingdom, and Denmark to perform a replicate Mendelian randomization analysis. This data set included 4 iron status biomarkers, namely, ferritin, total iron binding capacity, iron, and transferrin saturation (TSAT). The confounders in these data sets have been adjusted to mitigate the collider bias. We acquired summary statistics data sets for functional outcomes following IS from the gene-wide association study meta-analysis conducted by the Genetics of Ischemic Stroke Functional Outcome Consortium. The genetic estimates for functional outcomes at 90 days after IS were evaluated by the modified Rankin Scale score, including 3741 cases with good functional outcomes (modified Rankin Scale score, 0-2) and 2280 subjects with poor functional outcomes poststroke (modified Rankin Scale score, 3-6). Inverse variance weighting was used as the primary method, complemented by sensitivity analyses for pleiotropy and increasing robustness.

RESULTS

Reported with odds ratios (ORs) of stroke outcome with per SD unit increase in genetically determined iron status biomarker, TSAT and iron were associated with poor functional outcome after IS (TSAT: OR, 1.36 [95% CI, 1.23-1.50]; P=2.27×10-9; iron: OR, 1.44 [95% CI, 1.13-1.85]; P=0.0033). In replicate Mendelian randomization analysis, the detrimental effects of iron on poor functional outcome after IS remained stable (OR, 1.60 [95% CI, 1.24-2.08]; P=0.0003). In the meta-analysis, iron and TSAT were associated with poor functional outcomes after IS (TSAT: ORmeta, 1.35 [95% CI, 1.23-1.48]; iron: ORmeta, 1.51 [95% CI, 1.27-1.81]). Through sensitivity analyses and reverse Mendelian randomization analyses, we confirmed the robustness of the results.

CONCLUSIONS

Our study provides evidence suggesting a potential causal relationship between iron status and poor functional outcomes after IS. Future studies are required to illuminate the underlying mechanism.

Global Transcriptome Analysis Reveals Distinct Phases of the Endothelial Response to TNF

The vascular endothelium acts as a dynamic interface between blood and tissue. TNF-α, a major regulator of inflammation, induces endothelial cell (EC) transcriptional changes, the overall response dynamics of which have not been fully elucidated. In the present study, we conducted an extended time-course analysis of the human EC response to TNF, from 30 min to 72 h. We identified regulated genes and used weighted gene network correlation analysis to decipher coexpression profiles, uncovering two distinct temporal phases: an acute response (between 1 and 4 h) and a later phase (between 12 and 24 h). Sex-based subset analysis revealed that the response was comparable between female and male cells. Several previously uncharacterized genes were strongly regulated during the acute phase, whereas the majority in the later phase were IFN-stimulated genes. A lack of IFN transcription indicated that this IFN-stimulated gene expression was independent of de novo IFN production. We also observed two groups of genes whose transcription was inhibited by TNF: those that resolved toward baseline levels and those that did not. Our study provides insights into the global dynamics of the EC transcriptional response to TNF, highlighting distinct gene expression patterns during the acute and later phases. Data for all coding and noncoding genes is provided on the Web site (http://www.endothelial-response.org/). These findings may be useful in understanding the role of ECs in inflammation and in developing TNF signaling-targeted therapies.

Expression and Localization of Ferritin-Heavy Chain Predicts Recurrence for Breast Cancer Patients with a BRCA1/2 Mutation

The ferritin-heavy chain (FTH1) is the catalytic subunit of the ferroxidase ferritin, which prevents oxidative DNA damage via intracellular iron storage. FTH1 was shown to be a prognostic marker for triple-negative breast cancer (BC) patients and associated with an enrichment of CD8+ effector T cells. However, whether the expression and localization of FTH1 are also associated with clinical outcome in other BC subtypes is unknown. Here, we investigated the association of FTH1 with time to survival in BCs from 222 BRCA1/2 mutation carriers by immunohistochemistry on tissue microarrays. In addition, for 51 of these patients, the association between FTH1 and specific subsets of T cells was evaluated on whole slides using automatic scoring algorithms. We revealed that nuclear FTH1 (nFTH1) expression, in multivariable analyses, was associated with a shorter disease-free (HR = 2.71, 95% CI = 1.49-4.92, p = 0.001) and metastasis-free survival (HR = 3.54, 95% CI = 1.45-8.66, p = 0.006) in patients carrying a BRCA1/2 mutation. However, we found no relation between cytoplasmic FTH1 expression and survival of BRCA1/2 mutation carriers. Moreover, we did not detect an association between FTH1 expression and the amount of CD45+ (p = 0.13), CD8+ (p = 0.18), CD4+ (p = 0.20) or FOXP3+ cells (p = 0.17). Consequently, the mechanism underlying the worse recurrence-free survival of nFTH1 expression in BRCA1/2 mutation carriers needs further investigation.

DNA methylation in poultry: a review

As an important epigenetic modification, DNA methylation is involved in many biological processes such as animal cell differentiation, embryonic development, genomic imprinting and sex chromosome inactivation. As DNA methylation sequencing becomes more sophisticated, it becomes possible to use it to solve more zoological problems. This paper reviews the characteristics of DNA methylation, with emphasis on the research and application of DNA methylation in poultry.

Assessing the Potential of Small Peptides for Altering Expression Levels of the Iron-Regulatory Genes FTH1 and TFRC and Enhancing Androgen Receptor Inhibitor Activity in In Vitro Prostate Cancer Models

Recent research highlights the key role of iron dyshomeostasis in the pathogenesis of prostate cancer (PCa). PCa cells are heavily dependent on bioavailable iron, which frequently results in the reprogramming of iron uptake and storage pathways. Although advanced-stage PCa is currently incurable, bioactive peptides capable of modulating key iron-regulatory genes may constitute a means of exploiting a metabolic adaptation necessary for tumor growth. Recent annual increases in PCa incidence have been reported, highlighting the urgent need for novel treatments. We examined the ability of LNCaP, PC3, VCaP, and VCaP-EnzR cells to form colonies in the presence of androgen receptor inhibitors (ARI) and a series of iron-gene modulating oligopeptides (FT-001-FT-008). The viability of colonies following treatment was determined with clonogenic assays, and the expression levels of FTH1 (ferritin heavy chain 1) and TFRC (transferrin receptor) were determined with quantitative polymerase chain reaction (PCR). Peptides and ARIs combined significantly reduced PCa cell growth across all phenotypes, of which two peptides were the most effective. Colony growth suppression generally correlated with the magnitude of concurrent increases in FTH1 and decreases in TFRC expression for all cells. The results of this study provide preliminary insight into a novel approach at targeting iron dysmetabolism and sensitizing PCa cells to established cancer treatments.

A novel view of ferritin in cancer

Since its discovery more than 85 years ago, ferritin has principally been known as an iron storage protein. However, new roles, beyond iron storage, are being uncovered. Novel processes involving ferritin such as ferritinophagy and ferroptosis and as a cellular iron delivery protein not only expand our thinking on the range of contributions of this protein but present an opportunity to target these pathways in cancers. The key question we focus on within this review is whether ferritin modulation represents a useful approach for treating cancers. We discussed novel functions and processes of this protein in cancers. We are not limiting this review to cell intrinsic modulation of ferritin in cancers, but also focus on its utility in the trojan horse approach in cancer therapeutics. The novel functions of ferritin as discussed herein realize the multiple roles of ferritin in cell biology that can be probed for therapeutic opportunities and further research.

The Interplay between Intracellular Iron Homeostasis and Neuroinflammation in Neurodegenerative Diseases

Iron is essential for life. Many enzymes require iron for appropriate function. However, dysregulation of intracellular iron homeostasis produces excessive reactive oxygen species (ROS) via the Fenton reaction and causes devastating effects on cells, leading to ferroptosis, an iron-dependent cell death. In order to protect against harmful effects, the intracellular system regulates cellular iron levels through iron regulatory mechanisms, including hepcidin-ferroportin, divalent metal transporter 1 (DMT1)-transferrin, and ferritin-nuclear receptor coactivator 4 (NCOA4). During iron deficiency, DMT1-transferrin and ferritin-NCOA4 systems increase intracellular iron levels via endosomes and ferritinophagy, respectively. In contrast, repleting extracellular iron promotes cellular iron absorption through the hepcidin-ferroportin axis. These processes are regulated by the iron-regulatory protein (IRP)/iron-responsive element (IRE) system and nuclear factor erythroid 2-related factor 2 (Nrf2). Meanwhile, excessive ROS also promotes neuroinflammation by activating the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). NF-κB forms inflammasomes, inhibits silent information regulator 2-related enzyme 1 (SIRT1), and induces pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β). Furthermore, 4-hydroxy-2,3-trans-nonenal (4-HNE), the end-product of ferroptosis, promotes the inflammatory response by producing amyloid-beta (Aβ) fibrils and neurofibrillary tangles in Alzheimer's disease, and alpha-synuclein aggregation in Parkinson's disease. This interplay shows that intracellular iron homeostasis is vital to maintain inflammatory homeostasis. Here, we review the role of iron homeostasis in inflammation based on recent findings.

Hereditary Hyperferritinemia

Ferritin is a ubiquitous protein that is present in most tissues as a cytosolic protein. The major and common role of ferritin is to bind Fe²⁺, oxidize it and sequester it in a safe form in the cell, and to release iron according to cellular needs. Ferritin is also present at a considerably low proportion in normal mammalian sera and is relatively iron poor compared to tissues. Serum ferritin might provide a useful and convenient method of assessing the status of iron storage, and its measurement has become a routine laboratory test. However, many additional factors, including inflammation, infection, metabolic abnormalities, and malignancy-all of which may elevate serum ferritin-complicate interpretation of this value. Despite this long history of clinical use, fundamental aspects of the biology of serum ferritin are still unclear. According to the high number of factors involved in regulation of ferritin synthesis, secretion, and uptake, and in its central role in iron metabolism, hyperferritinemia is a relatively common finding in clinical practice and is found in a large spectrum of conditions, both genetic and acquired, associated or not with iron overload. The diagnostic strategy to reveal the cause of hyperferritinemia includes family and personal medical history, biochemical and genetic tests, and evaluation of liver iron by direct or indirect methods. This review is focused on the forms of inherited hyperferritinemia with or without iron overload presenting with normal transferrin saturation, as well as a step-by-step approach to distinguish these forms to the acquired forms, common and rare, of isolated hyperferritinemia.

Ferritin Heavy Chain Binds Peroxiredoxin 6 and Inhibits Cell Proliferation and Migration

The H Ferritin subunit (FTH1), as well as regulating the homeostasis of intracellular iron, is involved in complex pathways that might promote or inhibit carcinogenesis. This function may be mediated by its ability to interact with different molecules. To gain insight into the FTH1 interacting molecules, we analyzed its interactome in HEK293T cells. Fifty-one proteins have been identified, and among them, we focused our attention on a member of the peroxiredoxin family (PRDX6), an antioxidant enzyme that plays an important role in cell proliferation and in malignancy development. The FTH1/PRDX6 interaction was further supported by co-immunoprecipitation, in HEK293T and H460 cell lines and by means of computational methods. Next, we demonstrated that FTH1 could inhibit PRDX6-mediated proliferation and migration. Then, the results so far obtained suggested that the interaction between FTH1/PRDX6 in cancer cells might alter cell proliferation and migration, leading to a less invasive phenotype.

Proteomic changes in broiler liver by body weight differences under chronic heat stress

The increasing global temperature is causing economic losses and animal welfare problems in the poultry industry. Because poultry do not have sweat glands, it is difficult for them to return to their usual body temperature. Heat stress has negative impact on production and health in broilers. Given the effects of chronic stress on broilers, the objective of this study was to identify physiological changes in differentially expressed proteins in broilers with different growth performances using liver tissue from 35-day-old chickens (Ross-308). Changes in protein levels were analyzed with two-dimensional gel electrophoresis (2DE) and mass spectrometry. This study contained 2 groups (control and heat treatment groups) with 8 replicates per group. After d 20, ten birds were assigned to each replicate. On d 35, the heat treatment group was subdivided into 2 groups, a heat stressed high body weight group (HH) and a heat stressed low body weight group (HL). Body weight was lower in the heat treatment group than that in the control group. In the heat treatment group, the HH group had a significantly higher body weight than the HL group. The expression of heat shock protein 70 significantly increased in the HL group. Protein spots with significant differences in 2DE analysis were screened and selected. Thirteen significant spots were excised and analyzed using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). Among the 13 spots, 8 spots were identified. The identified spots were MRP-126, fatty acid binding protein, ferritin heavy chain, glutathione S-transferase, agmatinase; mitochondrial, alpha-enolase, 60 kDa heat shock protein; mitochondrial, and tubulin beta-7 chain. Our study has showed that high temperature stress aggravated oxidative stress in broilers, which resulted in comparatively slow growth to preserve body homeostasis.

Ferroptosis: Cancer Stem Cells Rely on Iron until "to Die for" It

Cancer stem cells (CSCs) are a distinct subpopulation of tumor cells with stem cell-like features. Able to initiate and sustain tumor growth and mostly resistant to anti-cancer therapies, they are thought responsible for tumor recurrence and metastasis. Recent accumulated evidence supports that iron metabolism with the recent discovery of ferroptosis constitutes a promising new lead in the field of anti-CSC therapeutic strategies. Indeed, iron uptake, efflux, storage and regulation pathways are all over-engaged in the tumor microenvironment suggesting that the reprogramming of iron metabolism is a crucial occurrence in tumor cell survival. In particular, recent studies have highlighted the importance of iron metabolism in the maintenance of CSCs. Furthermore, the high concentration of iron found in CSCs, as compared to non-CSCs, underlines their iron addiction. In line with this, if iron is an essential macronutrient that is nevertheless highly reactive, it represents their Achilles’ heel by inducing ferroptosis cell death and therefore providing opportunities to target CSCs. In this review, we first summarize our current understanding of iron metabolism and its regulation in CSCs. Then, we provide an overview of the current knowledge of ferroptosis and discuss the role of autophagy in the (regulation of) ferroptotic pathways. Finally, we discuss the potential therapeutic strategies that could be used for inducing ferroptosis in CSCs to treat cancer.

Iron Metabolism: An Under Investigated Driver of Renal Pathology in Lupus Nephritis

Nephritis is a common manifestation of systemic lupus erythematosus, a condition associated with inflammation and iron imbalance. Renal tubules are the work horse of the nephron. They contain a large number of mitochondria that require iron for oxidative phosphorylation, and a tight control of intracellular iron prevents excessive generation of reactive oxygen species. Iron supply to the kidney is dependent on systemic iron availability, which is regulated by the hepcidin-ferroportin axis. Most of the filtered plasma iron is reabsorbed in proximal tubules, a process that is controlled in part by iron regulatory proteins. This review summarizes tubulointerstitial injury in lupus nephritis and current understanding of how renal tubular cells regulate intracellular iron levels, highlighting the role of iron imbalance in the proximal tubules as a driver of tubulointerstitial injury in lupus nephritis. We propose a model based on the dynamic ability of iron to catalyze reactive oxygen species, which can lead to an accumulation of lipid hydroperoxides in proximal tubular epithelial cells. These iron-catalyzed oxidative species can also accentuate protein and autoantibody-induced inflammatory transcription factors leading to matrix, cytokine/chemokine production and immune cell infiltration. This could potentially explain the interplay between increased glomerular permeability and the ensuing tubular injury, tubulointerstitial inflammation and progression to renal failure in LN, and open new avenues of research to develop novel therapies targeting iron metabolism.

Opioid Modulation of Neuronal Iron and Potential Contributions to NeuroHIV

Opioid use has substantially increased over recent years and remains a major driver of new HIV infections worldwide. Clinical studies indicate that opioids may exacerbate the symptoms of HIV-associated neurocognitive disorders (HAND), but the mechanisms underlying opioid-induced cognitive decline remain obscure. We recently reported that the μ-opioid agonist morphine increased neuronal iron levels and levels of ferritin proteins that store iron, suggesting that opioids modulate neuronal iron homeostasis. Additionally, increased iron and ferritin heavy chain protein were necessary for morphine's ability to reduce the density of thin and mushroom dendritic spines in cortical neurons, which are considered critical mediators of learning and memory, respectively. As altered iron homeostasis has been reported in HAND and related neurocognitive disorders like Alzheimer's, Parkinson's, and Huntington's disease, understanding how opioids regulate neuronal iron metabolism may help identify novel drug targets in HAND with potential relevance to these other neurocognitive disorders. Here, we review the known mechanisms of opioid-mediated regulation of neuronal iron and corresponding cellular responses and discuss the implications of these findings for patients with HAND. Furthermore, we discuss a new molecular approach that can be used to understand if opioid modulation of iron affects the expression and processing of amyloid precursor protein and the contributions of this pathway to HAND.

Iron control of erythroid microtubule cytoskeleton as a potential target in treatment of iron-restricted anemia

Anemias of chronic disease and inflammation (ACDI) result from restricted iron delivery to erythroid progenitors. The current studies reveal an organellar response in erythroid iron restriction consisting of disassembly of the microtubule cytoskeleton and associated Golgi disruption. Isocitrate supplementation, known to abrogate the erythroid iron restriction response, induces reassembly of microtubules and Golgi in iron deprived progenitors. Ferritin, based on proteomic profiles, regulation by iron and isocitrate, and putative interaction with microtubules, is assessed as a candidate mediator. Knockdown of ferritin heavy chain (FTH1) in iron replete progenitors induces microtubule collapse and erythropoietic blockade; conversely, enforced ferritin expression rescues erythroid differentiation under conditions of iron restriction. Fumarate, a known ferritin inducer, synergizes with isocitrate in reversing molecular and cellular defects of iron restriction and in oral remediation of murine anemia. These findings identify a cytoskeletal component of erythroid iron restriction and demonstrate potential for its therapeutic targeting in ACDI.

Debilitating anemias in chronic diseases can result from deficient iron delivery to red cell precursors. Here, the authors show how this deficiency damages the cytoskeletal framework of progenitor cells and identify a targeted strategy for cytoskeletal repair, leading to anemia correction.

Hyperferritinemia in children hospitalized with scrub typhus

BACKGROUND

Hyperferritinemia is increasingly associated with mortality in sepsis. Studies estimating the prevalence of hyperferritinemia in pediatric scrub typhus are limited.

METHODS

This was a secondary analysis of a prospective observational study (FERRIS) from a tertiary care teaching hospital in North India where 72 children with confirmed scrub typhus, 4 (5.5%) PCR positive, 55 (76.4%)-IgM ELISA positive, and 13 (18.1%)-both PCR and ELISA positive, were analyzed. Serum ferritin was measured in 62 children to identify the prevalence of hyperferritinemia and determine its association with mortality.

RESULTS

Hyperferritinemia (> 500 μg/L) was seen in 72.6% [n = 45] children; 26 (41.9%) were mild (500-2000 μg/L), 13 (21%) were moderate (2000-10,000 μg/L), and 6 (9.7%) were severe (> 10,000 μg/L). Early presentation to hospital (≤ 7 days of febrile illness) had more survivors than late presentation (> 7 days). Non-survivors had significantly higher PRISM III, PELOD-2, hyperlactatemia, hypoalbuminemia, organ dysfunction, need for mechanical ventilation, and need of RRT. Ferritin had poor sensitivity and specificity in predicting survival with AUC of 0.56. Organ dysfunction and risk scores as PRISM III, PELOD 2, and VIS at admission were better predictors with AUC (95% CI) of 0.72 (0.56, 0.89), 0.77 (0.63, 0.92), and 0.90 (0.78, 1.0) respectively.

CONCLUSIONS

Hyperferritinemia is common in scrub typhus but it did not predict survival. Organ dysfunction and risk scores were better predictors of mortality than ferritin.

Mechanisms of neuronal dysfunction in HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorder (HAND) is characterized by cognitive and behavioral deficits in people living with HIV. HAND is still common in patients that take antiretroviral therapies, although they tend to present with less severe symptoms. The continued prevalence of HAND in treated patients is a major therapeutic challenge, as even minor cognitive impairment decreases patient’s quality of life. Therefore, modern HAND research aims to broaden our understanding of the mechanisms that drive cognitive impairment in people with HIV and identify promising molecular pathways and targets that could be exploited therapeutically. Recent studies suggest that HAND in treated patients is at least partially induced by subtle synaptodendritic damage and disruption of neuronal networks in brain areas that mediate learning, memory, and executive functions. Although the causes of subtle neuronal dysfunction are varied, reversing synaptodendritic damage in animal models restores cognitive function and thus highlights a promising therapeutic approach. In this review, we examine evidence of synaptodendritic damage and disrupted neuronal connectivity in HAND from clinical neuroimaging and neuropathology studies and discuss studies in HAND models that define structural and functional impairment of neurotransmission. Then, we report molecular pathways, mechanisms, and comorbidities involved in this neuronal dysfunction, discuss new approaches to reverse neuronal damage, and highlight current gaps in knowledge. Continued research on the manifestation and mechanisms of synaptic injury and network dysfunction in HAND patients and experimental models will be critical if we are to develop safe and effective therapies that reverse subtle neuropathology and cognitive impairment.

The relationship between serum erythropoietin, hepcidin, and haptoglobin levels with disease severity and other biochemical values in patients with COVID-19

Introduction

Studies have shown that iron metabolism is affected by coronavirus disease 19 (COVID‐19), which has spread worldwide and has become a global health problem. Our study aimed to evaluate the relationship between COVID‐19 and serum erythropoietin (EPO), hepcidin, and haptoglobin (Hpt) levels with disease severity, and other biochemical values.

Methods

Fifty nine COVID‐19 patients hospitalized in the intensive care unit (ICU) and wards in our hospital between March and June 2020 and 19 healthy volunteers were included in the study. Participants were divided into mild, severe, and critical disease severity groups. Group mean values were analyzed with SPSS according to disease severity, mortality, and intubation status.

Results

Hemoglobin (Hb) levels were significantly lower in the critical patient group (P < .0001) and deceased group (P < .0001). The red blood cell distribution width‐coefficient of variation (RDW‐CV) and ferritin values were significantly higher in the intubated (P = .001, P = .005) and deceased (P = .014, P = .003) groups. Ferritin values were positively correlated with disease severity (P < .0001). Serum iron levels were lower in the patient group compared with the reference range. (P < .0001). It was found that the transferrin saturation (TfSat) was lower in the patient group compared with the control group (P < .0001). It was found that the mean EPO of the deceased was lower than the control group and the survived patient group (P = .035). Hepcidin levels were found to be significantly lower in the patient group (P < .0001). Hpt values were found to be significantly lower in the intubated group (P = .004) and the deceased group (P = .042).

Conclusion

In our study, while serum iron and hepcidin levels decreased in patients diagnosed with COVID‐19, we found that EPO and Hpt levels were significantly lower in critical and deceased patient groups. Our study is the first study examining EPO and Hpt levels in patients diagnosed with COVID‐19.

Valuable clinical indicators for identifying infantile-onset inflammatory bowel disease patients with monogenic diseases

BACKGROUND

Infantile-onset inflammatory bowel disease (IO-IBD) occurs in very young children and causes severe clinical manifestations, which has poor responses to traditional inflammatory bowel disease (IBD) treatments. At present, there are no simple and reliable laboratory indicators for early screening IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.

AIM

To search for valuable indicators for early identifying IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.

METHODS

A retrospective analysis was performed in 73 patients with IO-IBD admitted to our hospital in the past 5 years. Based on the next-generation sequencing results, they were divided into a monogenic IBD group (M-IBD) and a non-monogenic IBD group (NM-IBD). Forty age-matched patients with allergic proctocolitis (AP) were included in a control group. The clinical manifestations and the inflammatory factors in peripheral blood were evaluated. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were used to identify the screening factors and cut-off values of IO-IBD as well as monogenic IO-IBD, respectively.

RESULTS

Among the 44 M-IBD patients, 35 carried IL-10RA mutations, and the most common mutations were c.301C>T (p.R101W, 30/70) and the c.537G>A (p.T179T, 17/70). Patients with higher serum tumor necrosis factor (TNF)-α value were more likely to have IBD [odds ratio (OR) = 1.25, 95% confidence interval (CI): 1.05-1.50, P = 0.013], while higher serum albumin level was associated with lower risk of IBD (OR = 0.86, 95%CI: 0.74-1.00, P = 0.048). The cut-off values of TNF-α and albumin were 17.40 pg/mL (sensitivity: 0.78; specificity: 0.88) and 36.50 g/L (sensitivity: 0.80; specificity: 0.90), respectively. The increased ferritin level was indicative of a genetic mutation in IO-IBD patients. Its cut-off value was 28.20 ng/mL (sensitivity: 0.93; specificity: 0.92). When interleukin (IL)-10 level was higher than 33.05 pg/mL (sensitivity: 1.00; specificity: 0.84), or the onset age was earlier than 0.21 mo (sensitivity: 0.82; specificity: 0.94), the presence of disease-causing mutations in IL-10RA in IO-IBD patients was strongly suggested.

CONCLUSION

Serum TNF-α and albumin level could differentiate IO-IBD patients from allergic proctocolitis patients, and serum ferritin and IL-10 levels are useful indicators for early diagnosing monogenic IO-IBD.

Inflaming the Brain with Iron

Iron accumulation and neuroinflammation are pathological conditions found in several neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Iron and inflammation are intertwined in a bidirectional relationship, where iron modifies the inflammatory phenotype of microglia and infiltrating macrophages, and in turn, these cells secrete diffusible mediators that reshape neuronal iron homeostasis and regulate iron entry into the brain. Secreted inflammatory mediators include cytokines and reactive oxygen/nitrogen species (ROS/RNS), notably hepcidin and nitric oxide (·NO). Hepcidin is a small cationic peptide with a central role in regulating systemic iron homeostasis. Also present in the cerebrospinal fluid (CSF), hepcidin can reduce iron export from neurons and decreases iron entry through the blood-brain barrier (BBB) by binding to the iron exporter ferroportin 1 (Fpn1). Likewise, ·NO selectively converts cytosolic aconitase (c-aconitase) into the iron regulatory protein 1 (IRP1), which regulates cellular iron homeostasis through its binding to iron response elements (IRE) located in the mRNAs of iron-related proteins. Nitric oxide-activated IRP1 can impair cellular iron homeostasis during neuroinflammation, triggering iron accumulation, especially in the mitochondria, leading to neuronal death. In this review, we will summarize findings that connect neuroinflammation and iron accumulation, which support their causal association in the neurodegenerative processes observed in AD and PD.

Iacta Alea Est: The Inexorable Advance of Tofacitinib in the Treatment of Dermatomyositis-Associated Rapidly Progressive Interstitial Lung Disease. A Case Report

Rapidly progressive interstitial lung disease is typically associated with clinically amyopathic dermatomyositis and the anti-melanoma differentiation associated gene 5 antibody, a condition with high mortality and resistance to classic immunosuppression. Recent reports have described the efficacy of the Janus kinase inhibitor tofacitinib in the treatment of rapidly progressive interstitial lung disease in anti-melanoma differentiation associated gene 5 antibody-positive clinically amyopathic dermatomyositis. It is uncertain, however, whether tofacitinib alters the course of rapidly progressive interstitial lung disease in other variants of dermatomyositis that are unrelated to the anti-melanoma differentiation associated gene 5 antibody and whether the early addition of the anti-fibrotic tyrosine kinase inhibitor nintedanib interferes with the development of fibrosis. To answer these questions, we present and discuss the case of an elderly woman who presented with a flare of dermatomyositis sine myositis. Based upon the detection of anti-Jo-1 antibodies and the absence of anti-melanoma differentiation associated gene 5 antibodies, anti-synthetase syndrome was diagnosed. While the cutaneous manifestations quickly resolved with prednisone, azathioprine and tacrolimus, the respiratory function paradoxically and rapidly deteriorated, and invoked the use of tofacitinib. Markedly raised ferritin levels and a severe numerical deficiency of circulating natural killer cells paralleled the acute lung inflammation, which was reflected by ¹⁸F-fluorodeoxyglucose hypermetabolism on positron emission tomography/CT. Tofacitinib lead to a prompt clinical recovery, with a reduction in oxygen requirement, correction of hyperferritinemia, reversal of the natural killer cell deficiency, and a decrease in ¹⁸F-fluorodeoxyglucose uptake in the affected lung segments. Subsequently, nintedanib was added at a point in time when inflammation subsided. Apart from cytomegalovirus reactivation no adverse events occurred. In conclusion, tofacitinib reversed the pronounced inflammatory component of anti-Jo-1 antibody-positive, anti-melanoma differentiation associated gene 5 antibody-negative rapidly progressive interstitial lung disease, confirming that Janus kinase signaling pathways are critically involved in the pathogenesis of rapidly progressive interstitial lung disease, apparently independently of the targeted autoantigen. Although some improvement in pulmonary function was observed, it seems premature to conclusively judge on reversibility or prevention of pulmonary fibrosis by pairing both kinase inhibitors for which an extended follow-up and ideally, prospective and controlled studies are needed.

FTH1 Pseudogenes in Cancer and Cell Metabolism

Ferritin, the principal intracellular iron-storage protein localized in the cytoplasm, nucleus, and mitochondria, plays a major role in iron metabolism. The encoding ferritin genes are members of a multigene family that includes some pseudogenes. Even though pseudogenes have been initially considered as relics of ancient genes or junk DNA devoid of function, their role in controlling gene expression in normal and transformed cells has recently been re-evaluated. Numerous studies have revealed that some pseudogenes compete with their parental gene for binding to the microRNAs (miRNAs), while others generate small interference RNAs (siRNAs) to decrease functional gene expression, and still others encode functional mutated proteins. Consequently, pseudogenes can be considered as actual master regulators of numerous biological processes. Here, we provide a detailed classification and description of the structural features of the ferritin pseudogenes known to date and review the recent evidence on their mutual interrelation within the complex regulatory network of the ferritin gene family.

Homocysteine-induced decrease in HUVEC cells' resistance to oxidative stress is mediated by Akt-dependent changes in iron metabolism

PURPOSE

Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases and also promotes neuronal death in various neurodegenerative diseases. There is evidence that iron can mediate homocysteine (Hcy) toxicity. Thus, the aim of this study was to investigate the effect of Hcy on iron metabolism in HUVEC and SH-SY5Y cells.

METHODS

HUVEC and SH-SY5Y cells were treated with 3 mM Hcy for a defined time.

RESULTS

We demonstrate that Hcy induced the upregulation of ferritins type L and H in HUVEC cells in a time-dependent manner and had no effect on the ferritins in SH-SY5Y cells. The change in ferritin expression was preceded by a significant decrease in the cellular level of the active form of Akt kinase in HUVEC but not in SH-SY5Y cells. An increase in ferritin L and H protein levels was observed in the Akt1, Akt2, Akt3 siRNA transfected cells, while in the cells transfected with FOXO3a siRNA, a decrease in both ferritins levels was noticed. Moreover, in the HUVEC cells treated with Hcy for 6 days, the active form of kinase Akt returned to the control level and it was accompanied by a drop in ferritin L and H protein levels. Cytotoxicity of hydrogen peroxide significantly increased in HUVEC cells pre-treated with Hcy for 24 h.

CONCLUSIONS

These data indicate that Hcy induces an increase in cellular ferritin level, and the process is mediated by alterations in Akt-FOXO3a signaling pathway.

COVID-19 as part of the hyperferritinemic syndromes: the role of iron depletion therapy

SARS-CoV-2 infection is characterized by a protean clinical picture that can range from asymptomatic patients to life-threatening conditions. Severe COVID-19 patients often display a severe pulmonary involvement and develop neutrophilia, lymphopenia, and strikingly elevated levels of IL-6. There is an over-exuberant cytokine release with hyperferritinemia leading to the idea that COVID-19 is part of the hyperferritinemic syndrome spectrum. Indeed, very high levels of ferritin can occur in other diseases including hemophagocytic lymphohistiocytosis, macrophage activation syndrome, adult-onset Still's disease, catastrophic antiphospholipid syndrome and septic shock. Numerous studies have demonstrated the immunomodulatory effects of ferritin and its association with mortality and sustained inflammatory process. High levels of free iron are harmful in tissues, especially through the redox damage that can lead to fibrosis. Iron chelation represents a pillar in the treatment of iron overload. In addition, it was proven to have an anti-viral and anti-fibrotic activity. Herein, we analyse the pathogenic role of ferritin and iron during SARS-CoV-2 infection and propose iron depletion therapy as a novel therapeutic approach in the COVID-19 pandemic.

FtH-Mediated ROS Dysregulation Promotes CXCL12/CXCR4 Axis Activation and EMT-Like Trans-Differentiation in Erythroleukemia K562 Cells

The cell-microenvironment communication is essential for homing of hematopoietic stem cells in stromal niches. Recent evidences support the involvement of epithelial-to-mesenchymal (EMT) process in hematopoietic stem cell homeostasis as well as in leukemia cells invasiveness and migration capability. Here, we demonstrate that the alteration of iron homeostasis and the consequent increase of redox metabolism, mediated by the stable knock down of ferritin heavy chain (FtH), enhances the expression of CXCR4 in K562 erythroleukemia cells, thus promoting CXCL12-mediated motility. Indeed, addition of the CXCR4 receptor antagonist AMD3100 reverts this effect. Upon FtH knock down K562 cells also acquire an “EMT-like” phenotype, characterized by the increase of Snail, Slug and Vimentin with the parallel loss of E-cadherin. By using fibronectin as substrate, the cell adhesion assay further shows a reduction of cell adhesion capability in FtH-silenced K562 cells. Accordingly, confocal microscopy shows that adherent K562 control cells display a variety of protrusions while FtH-silenced K562 cells remain roundish. These phenomena are largely due to the reactive oxygen species (ROS)-mediated up-regulation of HIF-1α/CXCR4 axis which, in turn, promotes the activation of NF-κB and the enhancement of EMT features. These data are confirmed by treatments with either N-acetylcysteine (NAC) or AMD3100 or NF-κB inhibitor IκB-alpha which revert the FtH-silenced K562 invasive phenotype. Overall, our findings demonstrate the existence of a direct relationship among iron metabolism, redox homeostasis and EMT in the hematological malignancies. The effects of FtH dysregulation on CXCR4/CXCL12-mediated K562 cell motility extend the meaning of iron homeostasis in the leukemia cell microenvironment.

Hyperferritinaemia: An Iron Sword of Autoimmunity

BACKGROUND

Ferritin is a molecule that plays many roles being the storage for iron, signalling molecule, and modulator of the immune response.

METHODS

Different electronic databases were searched in a non-systematic way to find out the literature of interest.

RESULTS

The level of ferritin rises in many inflammatory conditions including autoimmune disorders. However, in four inflammatory diseases (i.e., adult-onset Still's diseases, macrophage activation syndrome, catastrophic antiphospholipid syndrome, and sepsis), high levels of ferritin are observed suggesting it as a remarkable biomarker and pathological involvement in these diseases. Acting as an acute phase reactant, ferritin is also involved in the cytokine-associated modulator of the immune response as well as a regulator of cytokine synthesis and release which are responsible for the inflammatory storm.

CONCLUSION

This review article presents updated information on the role of ferritin in inflammatory and autoimmune diseases with an emphasis on hyperferritinaemic syndrome.

Ferritin: An Inflammatory Player Keeping Iron at the Core of Pathogen-Host Interactions

Iron is an essential element for virtually all cell types due to its role in energy metabolism, nucleic acid synthesis and cell proliferation. Nevertheless, if free, iron induces cellular and organ damage through the formation of free radicals. Thus, iron levels must be firmly controlled. During infection, both host and microbe need to access iron and avoid its toxicity. Alterations in serum and cellular iron have been reported as important markers of pathology. In this regard, ferritin, first discovered as an iron storage protein, has emerged as a biomarker not only in iron-related disorders but also in inflammatory diseases, or diseases in which inflammation has a central role such as cancer, neurodegeneration or infection. The basic research on ferritin identification and functions, as well as its role in diseases with an inflammatory component and its potential as a target in host-directed therapies, are the main considerations of this review.

Ferritins in Kidney Disease

Ferritins are evolutionarily conserved proteins that regulate cellular iron metabolism. It is the only intracellular protein that is capable of storing large quantities of iron. Although the ratio of different subunits determines the iron content of each ferritin molecule, the exact mechanism that dictates organization of these subunits still is unclear. In this review, we address renal ferritin expression and its implication in kidney disease. Specifically, we address the role of ferritin subunits in preventing kidney injury and also promoting tolerance against infection-associated kidney injury. We describe functions for ferritin that are independent of its ability to ferroxidize and store iron. We further discuss the implications of ferritin in body fluids, including blood and urine, during inflammation and kidney disease. Although there are several in-depth review articles on ferritin in the context of iron metabolism, we chose to focus on the role of ferritin particularly in kidney health and disease and highlight unanswered questions in the field.

Transferrin and H-ferritin involvement in brain iron acquisition during postnatal development: impact of sex and genotype

Iron delivery to the developing brain is essential for energy and metabolic support needed for processes such as myelination and neuronal development. Iron deficiency, especially in the developing brain, can result in a number of long-term neurological deficits that persist into adulthood. There is considerable debate that excess access to iron during development may result in iron overload in the brain and subsequently predispose individuals to age-related neurodegenerative diseases. There is a significant gap in knowledge regarding how the brain acquires iron during development and how biological variables such as development, genetics, and sex impact brain iron status. In this study, we used a mouse model expressing a mutant form of the iron homeostatic regulator protein HFE, (Hfe H63D), the most common gene variant in Caucasians, to determine impact of the mutation on brain iron uptake. Iron uptake was assessed using 59 Fe bound to either transferrin or H-ferritin as the iron carrier proteins. We demonstrate that at postnatal day 22, mutant mice brains take up greater amounts of iron compared with wildtype. Moreover, we introduce H-ferritin as a key protein in brain iron transport during development and identify a sex and genotype effect demonstrating female mutant mice take up more iron by transferrin, whereas male mutant mice take up more iron from H-ferritin at PND22. Furthermore, we begin to elucidate the mechanism for uptake using immunohistochemistry to profile the regional distribution and temporal expression of transferrin receptor and T-cell immunoglobulin and mucin domain 2, the latter is the receptor for H-ferritin. These data demonstrate that sex and genotype have significant effects on iron uptake and that regional receptor expression may play a large role in the uptake patterns during development. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/ Cover Image for this issue: doi: 10.1111/jnc.14731.

Bidirectional Regulation of Opioid and Chemokine Function

The opioid family of GPCRs consists of the classical opioid receptors, designated μ-, κ-, and δ-opioid receptors, and the orphanin-FQ receptor, and these proteins are expressed on both neuronal and hematopoietic cells. A number of laboratories have reported that an important degree of cross-talk can occur between the opioid receptors and the chemokine and chemokine receptor families. As a part of this, the opioid receptors are known to regulate the expression of certain chemokines and chemokine receptors, including those that possess strong pro-inflammatory activity. At the level of receptor function, it is clear that certain members of the chemokine family can mediate cross-desensitization of the opioid receptors. Conversely, the opioid receptors are all able to induce heterologous desensitization of some of the chemokine receptors. Consequently, activation of one or more of the opioid receptors can selectively cross-desensitize chemokine receptors and regulate chemokine function. These cross-talk processes have significant implications for the inflammatory response, since the regulation of both the recruitment of inflammatory cells, as well as the sensation of pain, can be controlled in this way.

Opioid and chemokine regulation of cortical synaptodendritic damage in HIV-associated neurocognitive disorders

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) persist despite effective antiretroviral therapies (ART). Evidence suggests that modern HAND is driven by subtle synaptodendritic damage in select brain regions, as ART-treated patients do not display overt neuronal death in postmortem brain studies. HAND symptoms are also aggravated by drug abuse, particularly with injection opioids. Opioid use produces region-specific synaptodendritic damage in similar brain regions, suggesting a convergent mechanism that may enhance HAND progression in opioid-using patients. Importantly, studies indicate that synaptodendritic damage and cognitive impairment in HAND may be reversible. Activation of the homeostatic chemokine receptor CXCR4 by its natural ligand CXCL12 positively regulates neuronal survival and dendritic spine density in cortical neurons, reducing functional deficits. However, the molecular mechanisms that underlie CXCR4, as well as opioid-mediated regulation of dendritic spines are not completely defined. Here, we will consolidate studies that describe the region-specific synaptodendritic damage in the cerebral cortex of patients and animal models of HAND, describe the pathways by which opioids may contribute to cortical synaptodendritic damage, and discuss the prospects of using the CXCR4 signaling pathway to identify new approaches to reverse dendritic spine deficits. Additionally, we will discuss novel research questions that have emerged from recent studies of CXCR4 and µ-opioid actions in the cortex. Understanding the pathways that underlie synaptodendritic damage and rescue are necessary for developing novel, effective therapeutics for this growing patient population.

Ferritin expression in the periodontal tissues of primates

Ferritin, an iron-binding protein, is composed of two subunits, ferritin heavy chain and ferritin light chain. It regulates many biological functions, such as proliferation, angiogenesis, and immunosuppression. The objective of this study was to determine the expression and distribution of ferritin in the periodontal tissues of primates. First, we assessed the expression of ferritin in primary cultured cells isolated from human periodontal tissues using the polymerase chain reaction and immunofluorescent staining in vitro. Second, we investigated the expression and distribution of ferritin in the periodontal tissues of Macaca fascicularis, human gingival tissues, and human gingival carcinoma tissues using immunohistochemistry in vivo. Both protein and mRNA of ferritin were constitutively present in human primary cultured cells, including those from the dental apical papilla, periodontal ligament, dental pulp, and gingival epithelium, as well as gingival fibroblasts. In M. fascicularis tissues, the immunohistochemical staining was particularly strong in blood vessel and mineralizing areas of the dental pulp and periodontal ligament. Ferritin heavy chain exhibited specific immunopositivity in the stratum basal of the epithelium in human gingival tissue, and strong immunostaining was found in peripheral regions of gingival carcinoma sites. Ferritin is constitutively present and widely distributed in the periodontal tissues of primates. Ferritin may play roles in epithelial proliferation, vascular angiogenesis, and mineralization in these tissues.

Morphine-Induced Modulation of Endolysosomal Iron Mediates Upregulation of Ferritin Heavy Chain in Cortical Neurons

HIV-associated neurocognitive disorders (HAND) remain prevalent and are aggravated by µ-opioid use. We have previously shown that morphine and other µ-opioids may contribute to HAND by inhibiting the homeostatic and neuroprotective chemokine receptor CXCR4 in cortical neurons, and this novel mechanism depends on upregulation of the protein ferritin heavy chain (FHC). Here, we examined the cellular events and potential mechanisms involved in morphine-mediated FHC upregulation using rat cortical neurons of either sex in vitro and in vivo. Morphine dose dependently increased FHC protein levels in primary neurons through µ-opioid receptor (µOR) and Gαi-protein signaling. Cytoplasmic FHC levels were significantly elevated, but nuclear FHC levels and FHC gene expression were unchanged. Morphine-treated rats also displayed increased FHC levels in layer 2/3 neurons of the prefrontal cortex. Importantly, both in vitro and in vivo FHC upregulation was accompanied by loss of mature dendritic spines, which was also dependent on µOR and Gαi-protein signaling. Moreover, morphine upregulated ferritin light chain (FLC), a component of the ferritin iron storage complex, suggesting that morphine altered neuronal iron metabolism. Indeed, prior to FHC upregulation, morphine increased cytoplasmic labile iron levels as a function of decreased endolysosomal iron. In line with this, chelation of endolysosomal iron (but not extracellular iron) blocked morphine-induced FHC upregulation and dendritic spine reduction, whereas iron overloading mimicked the effect of morphine on FHC and dendritic spines. Overall, these data demonstrate that iron mediates morphine-induced FHC upregulation and consequent dendritic spine deficits and implicate endolysosomal iron efflux to the cytoplasm in these effects.

Heme Catabolic Pathway in Inflammation and Immune Disorders

In recent years, the heme catabolic pathway is considered to play an important regulatory role in cell protection, apoptosis, inflammation, and other physiological and pathological processes. An appropriate amount of heme forms the basic elements of various life activities, while when released in large quantities, it can induce toxicity by mediating oxidative stress and inflammation. Heme oxygenase (HO) -1 can catabolize free heme into carbon monoxide (CO), ferrous iron, and biliverdin (BV)/bilirubin (BR). The diverse functions of these metabolites in immune systems are fascinating. Decades work shows that administration of degradation products of heme such as CO and BV/BR exerts protective activities in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS) and other immune disorders. This review elaborates the molecular and biochemical characterization of heme catabolic pathway, discusses the signal transduction and immunomodulatory mechanism in inflammation and summarizes the promising therapeutic strategies based on this pathway in inflammatory and immune disorders.

The role of ferritin and adiponectin as predictors of cartilage damage assessed by arthroscopy in patients with symptomatic knee osteoarthritis

The aim of the present study was to evaluate whether circulating serum ferritin and adiponectin (ADP) in the serum and synovial fluid correlate with cartilage damage severity assessed by arthroscopy in patients with knee osteoarthritis. The 40 subjects with symptomatic knee osteoarthritis were divided into four groups according to arthroscopy assessed cartilage damage, using Outerbridge (OB) grading. Group I included minor damage while Group IV included severe damage. Metabolic parameters, bone homeostasis, and insulin resistance markers were determined. Synovial fluid of the affected knee joint was obtained and assessed for synovial adiponectin levels. Parameters of bone homeostasis in the serum including levels of PTH, alkaline phosphatase, 25OH vitamin D, serum calcium and phosphorus were similar in the four groups. A significant difference in the level of serum ferritin was found: ferritin levels increased from Group 1 to Group 4 in a continuous fashion (p < 0.035). In General linear model (GLM) analysis significant by-group differences in circulating ferritin persisted even after adjustment (p = 0.030). Although all groups were similar in terms of serum ADP levels, between groups difference in synovial fluid ADP was found (p < 0.037). However, after controlling for the age, there was no between-group difference in terms of synovial ADP levels. Serum ferritin levels were associated with cartilage damage severity assessed by arthroscopy. This association was independent of age, sex, BMI, and CRP levels suggesting that ferritin may be actively involved in the progression of cartilage damage in patients with symptomatic knee OA.

Magnetoferritin: Process, Prospects, and Their Biomedical Applications

Ferritin is a spherical iron storage protein composed of 24 subunits and an iron core. Using biomimetic mineralization, magnetic iron oxide can be synthesized in the cavity of ferritin to form magnetoferritin (MFt). MFt, also known as a superparamagnetic protein, is a novel magnetic nanomaterial with good biocompatibility and flexibility for biomedical applications. Recently, it has been demonstrated that MFt had tumor targetability and a peroxidase-like catalytic activity. Thus, MFt, with its many unique properties, provides a powerful platform for tumor diagnosis and therapy. In this review, we discuss the biomimetic synthesis and biomedical applications of MFt.

Ferritin-based anticancer metallodrug delivery: Crystallographic, analytical and cytotoxicity studies

The encapsulation of anticancer metal-based drugs within a protein nanocage represents a valuable strategy to improve the efficacy and selectivity of these compounds towards cancer cells. The preparation, characterization of the in vitro cytotoxicity and X-ray structures of several ferritin-metallodrug nanocomposites (mainly containing platinum-, ruthenium- and gold-based anticancer agents) are here reviewed. The molecular mechanisms of action of these Ft-metallodrug adducts are discussed and future directions in the field are outlined.

Up-regulated ferritin in periodontitis promotes inflammatory cytokine expression in human periodontal ligament cells through transferrin receptor via ERK/P38 MAPK pathways

OBJECTIVE

Ferritin, an iron-binding protein, is ubiquitous and highly conserved; it plays a crucial role in inflammation, which is the main symptom of periodontitis. Full-length cDNA library analyses have demonstrated abundant expression of ferritin in human periodontal ligament. The aims of the present study were to explore how ferritin is regulated by local inflammation, and to investigate its functions and mechanisms of action in the process of periodontitis.

METHODS

Human gingival tissues were collected from periodontitis patients and healthy individuals. Experimental periodontitis was induced by ligature of second molars in mice. The expression of ferritin light polypeptide (FTL) and ferritin heavy polypeptide (FTH) were assessed by immunohistochemistry. Meanwhile, after stimulating human periodontal ligament cells (HPDLCs) with P. gingivalis-lipopolysaccharide (LPS), interleukin (IL)-6, and tumor necrosis factor-α (TNF-α), the expression of FTH and FTL were measured. Then, IL-6 and IL-8 were measured after incubation with different concentrations of apoferritin (iron-free ferritin) and several intracellular signaling pathway inhibitors, or after knockdown of the transferrin receptor.

RESULTS

Both FTH and FTL were substantially higher in inflamed periodontal tissues than in healthy tissues. The location of the elevated expression correlated well with the extent of inflammatory infiltration. Moreover, expression of FTH and FTL were enhanced after stimulation with P. gingivalis-LPS, IL-6, TNF-α. Apoferritin induced the production of IL-6 and IL-8 in a dose-dependent manner partly through binding to the transferrin receptor and activating ERK/P38 signaling pathways in HPDLCs.

CONCLUSIONS

Ferritin is up-regulated by inflammation and exhibits cytokine-like activity in HPDLCs inducing a signaling cascade that promotes expression of pro-inflammatory cytokines associated with periodontitis.

Screening, identification of prostate cancer urinary biomarkers and verification of important spots

Prostate-specific antigen (PSA) has been widely used as the unique serum biomarker for the diagnosis of prostate cancer (PCa). When PSA is moderately increased (e.g., 4-10 ng/ml), it is difficult to differentiate benign prostatic hyperplasia (BPH) from cancer. The diagnostic test (i.e., prostate biopsy) is invasive, adding pain and economic burden to the patient. Urine samples are more convenient, non-invasive and readily available than blood. We sought to determine whether ferritin might be the potential urinary biomarker in prostate cancer diagnosis. Using two-dimensional electrophoresis (2DE) followed by mass spectrometry (MS), differentially expressed urinary proteins among patients with PCa, BPH and normal controls were obtained. The ferritin heavy chain (FTH) gene, ferritin light chain (FTL) gene and protein expression of BPH-1 cells and PC-3 cells were analyzed by real-time quantitative PCR and Western blotting, respectively. Stable FTH or FTL silenced cell lines were generated by small hairpin(sh) RNA lentiviral transfection. The function of the cell lines was evaluated by the colony formation assay, transwell assay, and flow cytometry. Compared with BPH and normal controls, 15 overexpressed proteins, including FTH and FTL, were identified in the urine of the PCa group. FTH and FTL were also highly expressed in PC-3 cell lines compared with BPH-1 cells. FTH-silenced cells showed reduced cell proliferation, migration and increased cell apoptosis. FTL-silenced cells showed increased proliferation and migration abilities. There are differences in urinary proteins among patients with PCa, BPH and normal controls. FTH and FTL play different roles in PCa cells and are potential biomarkers for PCa.

Prognostic evaluation of serum ferritin in acute exacerbation of idiopathic pulmonary fibrosis

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) has an extremely poor prognosis. The role of ferritin in the pathogenesis of AE-IPF is not well known while serum ferritin is a key prognostic indicator for patients with clinically amyopathic dermatomyositis with rapidly progressive interstitial pneumonia.

OBJECTIVE

To elucidate the clinical importance of serum ferritin in patients with AE-IPF.

METHODS

Thirty-seven patients (48 episodes), who were diagnosed with AE-IPF and treated at our hospital between 1997 and 2015, were retrospectively studied.

RESULTS

Patients with AE-IPF had significantly higher levels of serum ferritin than baseline levels at the first diagnosis of IPF (P = 0.0017). Receiver operating characteristic analysis showed the cut-off value 174 ng/mL for the separation of AE (area under the curve, 0.700). No patients with AE-IPF were positive for anti- melanoma differentiation-associated gene 5 antibody. Patients with AE-IPF and higher ferritin (≥174 ng/mL) had lower %FVC and %DLCO before AE, and those with much higher ferritin (≥500 ng/mL) had significantly worse prognosis than those with lower ferritin (log-rank, P = 0.024). Immunohistochemical staining in autopsy specimens showed alveolar macrophages that were producing ferritin. Finally, in multivariate Cox proportional hazards analyses, serum ferritin level of ≥500 ng/mL was a significant worse prognostic factor (hazard ratio 5.280, P = 0.046).

CONCLUSION

Higher serum ferritin may be related to a worse prognosis in patients with AE-IPF.

Emerging and Dynamic Biomedical Uses of Ferritin

Ferritin, a ubiquitously expressed protein, has classically been considered the main iron cellular storage molecule in the body. Owing to the ferroxidase activity of the H-subunit and the nucleation ability of the L-subunit, ferritin can store a large amount of iron within its mineral core. However, recent evidence has demonstrated a range of abilities of ferritin that extends well beyond the scope of iron storage. This review aims to discuss novel functions and biomedical uses of ferritin in the processes of iron delivery, delivery of biologics such as chemotherapies and contrast agents, and the utility of ferritin as a biomarker in a number of neurological diseases.

Ferritin heavy chain is a negative regulator of ovarian cancer stem cell expansion and epithelial to mesenchymal transition

Objectives

Ferritin is the major intracellular iron storage protein essential for maintaining the cellular redox status. In recent years ferritin heavy chain (FHC) has been shown to be involved also in the control of cancer cell growth. Analysis of public microarray databases in ovarian cancer revealed a correlation between low FHC expression levels and shorter survival. To better understand the role of FHC in cancer, we have silenced the FHC gene in SKOV3 cells.

Results

FHC-KO significantly enhanced cell viability and induced a more aggressive behaviour. FHC-silenced cells showed increased ability to form 3D spheroids and enhanced expression of NANOG, OCT4, ALDH and Vimentin. These features were accompanied by augmented expression of SCD1, a major lipid metabolism enzyme. FHC apparently orchestrates part of these changes by regulating a network of miRNAs.

Methods

FHC-silenced and control shScr SKOV3 cells were monitored for changes in proliferation, migration, ability to propagate as 3D spheroids and for the expression of stem cell and epithelial-to-mesenchymal-transition (EMT) markers. The expression of three miRNAs relevant to spheroid formation or EMT was assessed by q-PCR.

Conclusions

In this paper we uncover a new function of FHC in the control of cancer stem cells.

shRNA targeting of ferritin heavy chain activates H19/miR-675 axis in K562 cells

PURPOSE

The heavy subunit of the iron storage protein ferritin (FHC) is essential for the intracellular iron metabolism and, at the same time, it represents a central hub of iron-independent pathways, such as cell proliferation, angiogenesis, p53 regulation, chemokine signalling, stem cell expansion, miRNAs expression. In this work we have explored the ability of FHC to modulate gene expression in K562 cells, through the up-regulation of the lncRNA H19 and its cognate miR-675.

MATERIALS AND METHODS

Targeted silencing of FHC was performed by lentiviral-driven shRNA strategy. FHC reconstitution was obtained by full length FHC cDNA transfection with Lipofectamine 2000. ROS amounts were determined with the redox-sensitive probe H2DCFDA. H19, miR-675, miR-107, Twist1, ID3, EPHB6, GNS, ANK1 and SMAD6 mRNA amounts were quantified by Taqman assay and qPCR analysis.

RESULTS

FHC silencing in K562 cells modulates gene expression through the up-regulation of the lncRNA H19 and its cognate miR-675. Experimental findings demonstrate that the molecular mechanism underlying this phenomenon is represented by an FHC knock-down-triggered increase in reactive oxygen species (ROS) production.

CONCLUSIONS

In this paper we uncover a so far not described function of the ferritin heavy subunit in the control of lncRNA pathways.

FTH1 expression is affected by promoter polymorphism and not DNA methylation in response to DHV-1 challenge in duck

Ferritin heavy polypeptide 1 (FTH1) plays a pivotal role in response to viral infections. FTH1 expression is modulated by various pathogens, but the regulatory mechanisms are unknown. We firstly construct duck hepatitis virus 1 (DHV-1) infection model, including morbid ducklings, non-morbid ducklings and control ducklings. Then the mRNA expression of duck FTH1 (duFTH1) was measured mRNA expression of duck FTH1 (duFTH1) in the liver and spleen after duck hepatitis virus 1 (DHV-1) infection using quantitative polymerase chain reaction (qPCR) and found that duFTH1 mRNA was down-regulated significantly in morbid ducklings (liver, P < 0.01; spleen, P < 0.05) compared with the control ducklings. We also found that duFTH1 expression was significantly higher in the spleen (P < 0.01) and liver (P < 0.05) of non-morbid ducklings than in morbid ducklings. Moreover, DNA methylation of the duFTH1 promoter was examined by bisulfite sequencing (BSP) and we found that the duFTH1 promoter was hypomethylated, the relative methylation was only 5.9% and 2.0% in the morbid ducklings and non-morbid ducklings, respectively. The promoter contained a -55 C/T mutation in 75% of non-morbid ducklings, and this polymorphism affected promoter activity. Further analysis suggested that this mutation altered the binding site of the transcription factor NRF1. Binding of NRF1 to the FTH1 promoter was confirmed by electrophoretic mobility shift assay (EMSA) analysis. Thus, our findings revealed the NRF1 was a negative regulator, and lossed of binding of NRF1 to duFTH1 promoter due to -55C/T mutation enhances duFTH1 expression in non-morbid ducks, which provided molecular insights into the effect of duFTH1 expression via promoter polymorphisms, but not DNA methylation, in response to DHV-1 challenge.

Hyperferritinemia and inflammation

Understanding of ferritin biology has traditionally centered on its role in iron storage and homeostasis, with low ferritin levels indicative of deficiency and high levels indicative of primary or secondary hemochromatosis. However, further work has shown that iron, redox biology and inflammation are inexorably linked. During infection, increased ferritin levels represent an important host defense mechanism that deprives bacterial growth of iron and protects immune cell function. It may also be protective, limiting the production of free radicals and mediating immunomodulation. Additionally, hyperferritinemia is a key acute-phase reactants, used by clinicians as an indication for therapeutic intervention, aimed at controlling inflammation in high-risk patients. One school of thought maintains that hyperferritinemia is an 'innocent bystander' biomarker of uncontrolled inflammation that can be used to gauge effectiveness of intervention. Other schools of thought maintain that ferritin induction could be a protective negative regulatory loop. Others maintain that ferritin is a key mediator of immune dysregulation, especially in extreme hyperferritinemia, via direct immune-suppressive and pro-inflammatory effects. There is a clear need for further investigation of the role of ferritin in uncontrolled inflammatory conditions both as a biomarker and mediator of disease because its occurrence identifies patients with high mortality risk and its resolution predicts their improved survival.

Epithelial-to-mesenchymal transition in FHC-silenced cells: the role of CXCR4/CXCL12 axis

Background

Ferritin plays a central role in the intracellular iron metabolism; the molecule is a nanocage of 24 subunits of the heavy and light types. The heavy subunit (FHC) is provided of a ferroxidase activity and thus performs the key transformation of iron in a non-toxic form. Recently, it has been shown that FHC is also involved in additional not iron-related critical pathways including, among the others, p53 regulation, modulation of oncomiRNAs expression and chemokine signalling. Epithelial to mesenchymal transition (EMT) is a cellular mechanism by which the cell acquires a fibroblast-like phenotype along with a decreased adhesion and augmented motility. In this work we have focused our attention on the role of the FHC on EMT induction in the human cell lines MCF-7 and H460 to elucidate the underlying molecular mechanisms.

Methods

Targeted silencing of the FHC was performed by lentiviral-driven shRNA strategy. Reconstitution of the FHC gene product was obtained by full length FHC cDNA transfection with Lipofectamine 2000. MTT and cell count assays were used to evaluate cell viability and proliferation; cell migration capability was assayed by the wound-healing assay and transwell strategy. Quantification of the CXCR4 surface expression was performed by flow cytometry.

Results

Experimental data indicated that FHC-silenced MCF-7 and H460 cells (MCF-7^shFHC, H460^shFHC) acquire a mesenchymal phenotype, accompanied by a significant enhancement of their migratory and proliferative capacity. This shift is coupled to an increase in ROS production and by an activation of the CXCR4/CXCL12 signalling pathway. We present experimental data indicating that the cytosolic increase in ROS levels is responsible for the enhanced proliferation of FHC-silenced cells, while the higher migration rate is attributable to a dysregulation of the CXCR4/CXCL12 axis.

Conclusions

Our findings indicate that induction of EMT, increased migration and survival depend, in MCF-7 and H460 cells, on the release of FHC control on two pathways, namely the iron/ROS metabolism and CXCR4/CXCL12 axis. Besides constituting a further confirmation of the multifunctional nature of FHC, this data also suggest that the analysis of FHC amount/function might be an important additional tool to predict tumor aggressiveness.

Fumarate Mediates a Chronic Proliferative Signal in Fumarate Hydratase-Inactivated Cancer Cells by Increasing Transcription and Translation of Ferritin Genes

Germ line mutations of the gene encoding the tricarboxylic acid (TCA) cycle enzyme fumarate hydratase (FH) cause a hereditary cancer syndrome known as hereditary leiomyomatosis and renal cell cancer (HLRCC). HLRCC-associated tumors harbor biallelic FH inactivation that results in the accumulation of the TCA cycle metabolite fumarate. Although it is known that fumarate accumulation can alter cellular signaling, if and how fumarate confers a growth advantage remain unclear. Here we show that fumarate accumulation confers a chronic proliferative signal by disrupting cellular iron signaling. Specifically, fumarate covalently modifies cysteine residues on iron regulatory protein 2 (IRP2), rendering it unable to repress ferritin mRNA translation. Simultaneously, fumarate increases ferritin gene transcription by activating the NRF2 (nuclear factor [erythroid-derived 2]-like 2) transcription factor. In turn, increased ferritin protein levels promote the expression of the promitotic transcription factor FOXM1 (Forkhead box protein M1). Consistently, clinical HLRCC tissues showed increased expression levels of both FOXM1 and its proliferation-associated target genes. This finding demonstrates how FH inactivation can endow cells with a growth advantage.

IL-1β/IL-6/CRP and IL-18/ferritin: Distinct Inflammatory Programs in Infections

The host inflammatory response against infections is characterized by the release of pro-inflammatory cytokines and acute-phase proteins, driving both innate and adaptive arms of the immune response. Distinct patterns of circulating cytokines and acute-phase responses have proven indispensable for guiding the diagnosis and management of infectious diseases. This review discusses the profiles of acute-phase proteins and circulating cytokines encountered in viral and bacterial infections. We also propose a model in which the inflammatory response to viral (IL-18/ferritin) and bacterial (IL-6/CRP) infections presents with specific plasma patterns of immune biomarkers.