Virus induces metal-binding proteins and changed trace element balance in the brain during the course of a common human infection (coxsackievirus B3) in mice

Unveiling the intersection: ferroptosis in influenza virus infection

The influenza virus (IFV) imposes a considerable health and economic burden globally, requiring a comprehensive understanding of its pathogenic mechanisms. Ferroptosis, an iron-dependent lipid peroxidation cell death pathway, holds unique implications for the antioxidant defense system, with possible contributions to inflammation. This exploration focuses on the dynamic interplay between ferroptosis and the host defense against viruses, emphasizing the influence of IFV infections on the activation of the ferroptosis pathway. IFV causes different types of cell death, including apoptosis, necrosis, and ferroptosis. IFV-induced ferroptotic cell death is mediated by alterations in iron homeostasis, intensifying the accumulation of reactive oxygen species and promoting lipid peroxidation. A comprehensive investigation into the mechanism of ferroptosis in viral infections, specifically IFV, has great potential to identify therapeutic strategies. This understanding may pave the way for the development of drugs using ferroptosis inhibitors, presenting an effective approach to suppress viral infections.

Ferroptosis, from the virus point of view: opportunities and challenges

Ferroptosis is a new type of cell death, which is mainly dependent on the formation and accumulation of reactive oxygen species and lipid peroxides mediated by iron. It is distinct from other forms of regulation of cell death in morphology, immunology, biochemistry, and molecular biology. Various cell death mechanisms have been observed in many viral infections, and virus-induced cell death has long been considered as a double-edged sword that can inhibit or aggravate viral infections. However, understanding of the role of ferroptosis in various viral infections is limited. Special attention will be paid to the mechanisms of ferroptosis in mediating viral infection and antiviral treatment associated with ferroptosis. In this paper, we outlined the mechanism of ferroptosis. Additionally, this paper also review research on ferroptosis from the perspective of the virus, discussed the research status of ferroptosis in virus infection and classified and summarized research on the interaction between viral infections and ferroptosis.

The Role of the NRF2 Pathway in the Pathogenesis of Viral Respiratory Infections

In humans, acute and chronic respiratory infections caused by viruses are associated with considerable morbidity and mortality. Respiratory viruses infect airway epithelial cells and induce oxidative stress, yet the exact pathogenesis remains unclear. Oxidative stress activates the transcription factor NRF2, which plays a key role in alleviating redox-induced cellular injury. The transcriptional activation of NRF2 has been reported to affect both viral replication and associated inflammation pathways. There is complex bidirectional crosstalk between virus replication and the NRF2 pathway because virus replication directly or indirectly regulates NRF2 expression, and NRF2 activation can reversely hamper viral replication and viral spread across cells and tissues. In this review, we discuss the complex role of the NRF2 pathway in the regulation of the pathogenesis of the main respiratory viruses, including coronaviruses, influenza viruses, respiratory syncytial virus (RSV), and rhinoviruses. We also summarize the scientific evidence regarding the effects of the known NRF2 agonists that can be utilized to alter the NRF2 pathway.

Free Radical and Viral Infection: A Review from the Perspective of Ferroptosis

Free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), play critical roles in various physiological activities such as cell differentiation, apoptosis, and vascular tension when existing in cells at low levels. However, excessive amounts of free radicals are harmful, causing DNA damage, lipid peroxidation, protein degeneration, and abnormal cell death. Certain viral infections induce cells to produce excessive free radicals, which in multiple ways help the virus to replicate, mature, and exit. Iron is a necessary element for many intracellular enzymes, involved in both cellular activities and viral replication. Ferroptosis, a programmed cell death mode distinct from apoptosis, necrosis, and pyroptosis, is characterized by lipid peroxide accumulation and damage to the antioxidant system, affecting many cellular processes. Viral infection commonly manifests as decreased glutathione (GSH) content and down-regulated glutathione peroxidase 4 (GPX4) activity, similar to ferroptosis. Recent studies have suggested a possible relationship among free radicals, viral infections and ferroptosis. This review aims to elucidate the molecular mechanism linking free radicals and ferroptosis during viral infections and provide a new theoretical basis for studying viral pathogenesis and control.

Ferroptosis in viral infection: the unexplored possibility

Virus-induced cell death has long been thought of as a double-edged sword in the inhibition or exacerbation of viral infections. The vital role of iron, an essential element for various enzymes in the maintenance of cellular physiology and efficient viral replication, places it at the crossroads and makes it a micronutrient of competition between the viruses and the host. Viruses can interrupt iron uptake and the antioxidant response system, while others can utilize iron transporter proteins as receptors. Interestingly, the unavailability of iron facilitates certain viral infections and causes cell death characterized by lipid peroxide accumulation and malfunction of the antioxidant system. In this review, we discuss how iron uptake, regulation and metabolism, including the redistribution of iron in the host defense system during viral infection, can induce ferroptosis. Fenton reactions, a central characteristic of ferroptosis, are caused by the increased iron content in the cell. Therefore, viral infections that increase cellular iron content or intestinal iron absorption are likely to cause ferroptosis. In addition, we discuss the hijacking of the iron regulatoy pathway and the antioxidant response, both of which are typical in viral infections. Understanding the potential signaling mechanisms of ferroptosis in viral infections will aid in the development of new therapeutic agents.

Metallothionein: a Potential Link in the Regulation of Zinc in Nutritional Immunity

Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a "delicate" balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)-a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.

Trace Element Concentrations in Human Tissues of Death Cases Associated With Secondary Infection and MOF After Severe Trauma

Proper trace element level is crucial for the organs in maintaining normal physiological functions. Multiple organ failure (MOF) might be added to critically ill patients due to a lack of trace elements. Alterations of trace element levels in brain, heart, liver, and kidney after severe trauma, however, have been little studied so far. In this study, tissue samples of the frontal cortex of the brain, interventricular septum of the heart, right lobe of the liver, and upper pole of the kidney were obtained from forensic autopsies, of which 120 cases died during the 5th to 15th day of hospitalization, whereas the trauma death group and 43 cases immediately died due to severe craniocerebral trauma as the control group. Copper (Cu), iron (Fe), zinc (Zn), and selenium (Se) were quantified by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). Cu, Fe, Zn, and Se concentrations in the brain, heart, liver, and kidney in the trauma group decreased dramatically (p<0.05) compared to the control group. The incidence of secondary infection and multiple organ failure (MOF) in the trauma death group were 78.33 and 29.17%, respectively. The concentrations of all elements exhibited a significant correlation with secondary infection and MOF (p<0.01). Our data suggest that low concentrations of Cu, Fe, Zn, and Se in pivotal organs may contribute to the incidence of secondary infection and MOF after severe trauma, which to some extent results in death.

Redox Regulation and the Autistic Spectrum: Role of Tryptophan Catabolites, Immuno-inflammation, Autoimmunity and the Amygdala

The autistic spectrum disorders (ASD) form a set of multi-faceted disorders with significant genetic, epigenetic and environmental determinants. Oxidative and nitrosative stress (O&NS), immuno-inflammatory pathways, mitochondrial dysfunction and dysregulation of the tryptophan catabolite (TRYCATs) pathway play significant interactive roles in driving the early developmental etiology and course of ASD. O&NS interactions with immuno-inflammatory pathways mediate their effects centrally via the regulation of astrocyte and microglia responses, including regional variations in TRYCATs produced. Here we review the nature of these interactions and propose an early developmental model whereby different ASD genetic susceptibilities interact with environmental and epigenetic processes, resulting in glia biasing the patterning of central interarea interactions. A role for decreased local melatonin and N-acetylserotonin production by immune and glia cells may be a significant treatment target.

Long-term intermittent hypoxia elevates cobalt levels in the brain and injures white matter in adult mice

STUDY OBJECTIVES

Exposure to the variable oxygenation patterns in obstructive sleep apnea (OSA) causes oxidative stress within the brain. We hypothesized that this stress is associated with increased levels of redox-active metals and white matter injury.

DESIGN

Participants were randomly allocated to a control or experimental group (single independent variable).

SETTING

University animal house.

PARTICIPANTS

Adult male C57BL/6J mice.

INTERVENTIONS

To model OSA, mice were exposed to long-term intermittent hypoxia (LTIH) for 10 hours/day for 8 weeks or sham intermittent hypoxia (SIH).

MEASUREMENTS AND RESULTS

Laser ablation-inductively coupled plasma-mass spectrometry was used to quantitatively map the distribution of the trace elements cobalt, copper, iron, and zinc in forebrain sections. Control mice contained 62 ± 7 ng cobalt/g wet weight, whereas LTIH mice contained 5600 ± 600 ng cobalt/g wet weight (P < 0.0001). Other elements were unchanged between conditions. Cobalt was concentrated within white matter regions of the brain, including the corpus callosum. Compared to that of control mice, the corpus callosum of LTIH mice had significantly more endoplasmic reticulum stress, fewer myelin-associated proteins, disorganized myelin sheaths, and more degenerated axon profiles. Because cobalt is an essential component of vitamin B12, serum methylmalonic acid (MMA) levels were measured. LTIH mice had low MMA levels (P < 0.0001), indicative of increased B12 activity.

CONCLUSIONS

Long-term intermittent hypoxia increases brain cobalt, predominantly in the white matter. The increased cobalt is associated with endoplasmic reticulum stress, myelin loss, and axonal injury. Low plasma methylmalonic acid levels are associated with white matter injury in long-term intermittent hypoxia and possibly in obstructive sleep apnea.

Total blood mercury and serum measles antibodies in US children, NHANES 2003-2004

BACKGROUND

Environmental toxins, pathogens and host susceptibility cofactors may interact to contribute to disease. In vitro mercury exposure inhibited antiviral cytokines in human cells; however, little is known about the relationship between mercury and viruses in children. Children are susceptible to mercury toxicity; lower vitamin B-12 and folate levels and higher homocysteine levels may represent susceptibility cofactors. This study aimed to evaluate associations between total blood mercury (Hg) and measles antibodies in children, and the influence of these susceptibility cofactors.

DESIGN

Cross-sectional data on serum measles antibodies, Hg, homocysteine, methylmalonic acid (MMA, indicator of B-12 deficiency), and folate were obtained from the 2003-2004 NHANES for children aged 6-11 years with measles seropositivity (n=692). We used linear regression to evaluate relationships between measles antibodies and Hg, stratified by sex, MMA ≥, folate <, and homocysteine≥sample medians, adjusted for demographic, nutritional and environmental cofactors.

RESULTS

Hg (range: 0.10-19.10μg/L) was inversely associated with measles antibodies (range: 1.00-28.24 units) in non-stratified analysis (n=692), yet positively associated among the subset of boys with higher MMA and lower folate (n=98). Among this subset with higher homocysteine levels (n=61), correlations were positive across all Hg quartiles relative to Q1 (Hg≤0.20μg/L): Q2:β=6.60 (3.02, 10.19); Q3:β=8.49 (6.17, 10.81); Q4 (Hg>0.80μg/L):β=4.90 (2.12, 7.67) (p(trend)=0.077).

CONCLUSION

Stratification by susceptibility cofactors revealed opposing directionality for correlations between Hg and measles antibodies, with positive effect estimates at lowest exposures only among boys with higher MMA, lower folate and higher homocysteine levels.

Gastrointestinal uptake of trace elements are changed during the course of a common human viral (Coxsackievirus B3) infection in mice

Most infectious diseases are accompanied by a change in levels of several trace elements in the blood. However, it is not known whether changes in the gastrointestinal uptake of trace elements contribute to this event. Coxsackievirus B3 (CVB3), adapted to Balb/c mice, was used to study whether infection induces gene expression of metallothionein (MT1) and divalent-metal transporter 1 (DMT1) in the intestine and liver and hepcidin in the liver, as well as whether trace elements in these tissues are changed accordingly. Quantitative expression of CVB3, MT1, DMT1 and hepcidin was measured by real-time RT-PCR and six trace elements by ICP-MS on days 3, 6 and 9 of the infection. The copper/zinc (Cu/Zn) ratio in serum increased as a response to the infection. High concentrations of virus were found in the intestine and liver on day 3 and in the intestine on day 6. MT1 in the intestine and liver increased on days 3 and 6. The increase of MT1 in the liver correlated positively with Cu and Zn. Hepcidin in the liver showed a non-significant increase on days 3 and 6 of the infection, whereas DMT1 in the intestine decreased on day 9. Accordingly, iron (Fe) in the liver increased progressively during the disease, whereas in the intestine DMT1 was negatively correlated to Fe. Arsenic (As), cadmium (Cd) and mercury (Hg) were found to decrease to various degrees in the intestine, serum and liver. Thus, enteroviral infections, and possibly many other infections, may cause a change in the gastrointestinal uptake of both non-essential and essential trace elements.