An overview on in vitro and in vivo antiviral activity of lactoferrin: its efficacy against SARS-CoV-2 infection.

Beyond the absolute and indisputable relevance and efficacy of anti-SARS-CoV-2 vaccines, the rapid transmission, the severity of infection, the absence of the protection on immunocompromised patients, the propagation of variants, the onset of infection and/or disease in vaccinated subjects and the lack of availability of worldwide vaccination require additional antiviral treatments. Since 1987, lactoferrin (Lf) is well-known to possess an antiviral activity related to its physico-chemical properties and to its ability to bind to both heparan sulfate proteoglycans (HSPGs) of host cells and/or surface components of viral particles. In the present review, we summarize in vitro and in vivo studies concerning the efficacy of Lf against DNA, RNA, enveloped and non-enveloped viruses. Recent studies have revealed that the in vitro antiviral activity of Lf is also extendable to SARS-CoV-2. In vivo, Lf oral administration in early stage of SARS-CoV-2 infection counteracts COVID-19 pathogenesis. In particular, the effect of Lf on SARS-CoV-2 entry, inflammatory homeostasis, iron dysregulation, iron-proteins synthesis, reactive oxygen formation, oxidative stress, gut-lung axis regulation as well as on RNA negativization, and coagulation/fibrinolysis balance will be critically reviewed. Moreover, the molecular mechanisms underneath, including the Lf binding to HSPGs and spike glycoprotein, will be disclosed and discussed. Taken together, present data not only support the application of the oral administration of Lf alone in asymptomatic COVID-19 patients or as adjuvant of standard of care practice in symptomatic ones but also constitute the basis for enriching the limited literature on Lf effectiveness for COVID-19 treatment.

Bioavailability of iron and its potential to improve the immune system and ward off COVID-19: a review

Iron is a mineral that plays an important role, especially to prevent anaemia through the production of red blood cells. Iron also plays a role in physiological processes, such as the activation of enzymes and hormones, as well as increasing the immune system in warding off various viral infections. Therefore, iron bioavailability needs to be considered to take the greatest benefit of iron. This review discussed the factors that can affect the bioavailability of iron, various technologies to increase the bioavailability, and its potential in enhancing the immune system. Iron bioavailability can be increased by fortification, fermentation, the addition of vitamin C, and iron encapsulation. Under conditions of adequate iron intake, iron plays an important role in enhancing the immune system through controlling lymphocytes and T cell proliferation. However, excess iron consumption can be at risk of weakening the host's immune response to viruses. Therefore, the appropriate level of iron intake must be maintained accurately to be used optimally and has the potential to ward off viral infections, including the Sars-CoV-2 virus as the cause of COVID-19.Copyright © 2023, Rynnye Lyan Resources. All rights reserved.

Lactoferrin for COVID-19 prevention, treatment, and recovery.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), a unique beta-coronavirus, has caused the most serious outbreak of the last century at the global level. SARS-CoV-2 infections were firstly reported in the city of Wuhan in China in 2019 and this new disease was named COVID-19 by World Health Organization (WHO). As this novel disease can easily be transmitted from one individual to another via respiratory droplets, many nations around the world have taken several precautions regarding the reduction in social activities and quarantine for the limitation of the COVID-19 transmission. SARS-CoV-2 is known to cause complications that may include pneumonia, acute respiratory distress syndrome (ARDS), multi-organ failure, septic shock, and death. To prevent and treat COVID-19, some significant studies have been conducted since the outbreak. One of the most noticeable therapeutic approaches is related to a multifunctional protein, lactoferrin. Lactoferrin (Lf) is an 80 kDa cationic glycoprotein that has a great range of benefits from improving the immunity to antiviral effects due to its unique characteristics such as the iron-binding ability. This review summarizes the characteristics of SARS-CoV-2 and the potential applications of Lf for the prevention, treatment, and recovery of COVID-19.

Lactoferrin Binding to SARS-CoV-2 Spike Glycoprotein Blocks Pseudoviral Entry and Relieves Iron Protein Dysregulation in Several In Vitro Models.

SARS-CoV-2 causes COVID-19, a predominantly pulmonary disease characterized by a burst of pro-inflammatory cytokines and an increase in free iron. The viral glycoprotein Spike mediates fusion to the host cell membrane, but its role as a virulence factor is largely unknown. Recently, the antiviral activity of lactoferrin against SARS-CoV-2 was demonstrated in vitro and shown to occur via binding to cell surface receptors, and its putative interaction with Spike was suggested by in silico analyses. We investigated the anti-SARS-CoV-2 activity of bovine and human lactoferrins in epithelial and macrophagic cells using a Spike-decorated pseudovirus. Lactoferrin inhibited pseudoviral fusion and counteracted the deleterious effects of Spike on iron and inflammatory homeostasis by restoring basal levels of iron-handling proteins and of proinflammatory cytokines IL-1ß and IL-6. Using pull-down assays, we experimentally proved for the first time that lactoferrin binds to Spike, immediately suggesting a mechanism for the observed effects. The contribution of transferrin receptor 1 to Spike-mediated cell fusion was also experimentally demonstrated. In silico analyses showed that lactoferrin interacts with transferrin receptor 1, suggesting a multifaceted mechanism of action for lactoferrin. Our results give hope for the use of bovine lactoferrin, already available as a nutraceutical, as an adjuvant to standard therapies in COVID-19.

The Influence of Viral Infections on Iron Homeostasis and the Potential for Lactoferrin as a Therapeutic in the Age of the SARS-CoV-2 Pandemic.

The association of hyperinflammation and hyperferritinemia with adverse outcomes in SARS-CoV-2-infected patients suggests an integral role for iron homeostasis in pathogenesis, a commonly described symptom of respiratory viral infections. This dysregulated iron homeostasis results in viral-induced lung injury, often lasting long after the acute viral infection; however, much remains to be understood mechanistically. Lactoferrin is a multipurpose glycoprotein with key immunomodulatory, antimicrobial, and antiviral functions, which can be found in various secreted fluids, but is most abundantly characterized in milk from all mammalian species. Lactoferrin is found at its highest concentrations in primate colostrum; however, the abundant availability of bovine-dairy-derived lactoferrin (bLf) has led to the use of bLf as a functional food. The recent research has demonstrated the potential value of bovine lactoferrin as a therapeutic adjuvant against SARS-CoV-2, and herein this research is reviewed and the potential mechanisms of therapeutic targeting are considered.

Hydroxychloroquine (HCQ) Exhibits Better Binding to the Main Protease (Mpro) Compared to Spike Protein (S protein) of SARS-CoV-2: An In-silico Analysis

Background: Despite various efforts in preventing and treating SARS-CoV-2 infec-tions;transmission and mortality have been increasing at alarming rates globally. Since its first oc-currence in Wuhan, China, in December 2019, the number of cases and deaths due to SARS-CoV--2 infection continues to increase across 220 countries. Currently, there are about 228 million cases and 4.6 million deaths recorded globally. Although several vaccines/drugs have been reported to prevent or treat SARS-CoV-2, their efficacy to protect against emerging variants and duration of protection are not fully known. Hence, more emphasis is given to repurpose the existing pharmacological agents to manage the infected individuals. One such agent is hydroxychloroquine (HCQ), which is a more soluble derivative of antimalarial drug chloroquine. HCQ has been tested in clinical trials to mitigate SARS-CoV-2 infection-induced complications while reducing the time to clinical recovery (TTCR). However, several concerns and questions about the utility and efficacy of HCQ for treating SARS-CoV-2 infected individuals still persist. Identifying key proteins regulated by HCQ is likely to provide vital clues required to address these concerns. Objective: The objective of this study is to identify the ability of HCQ for binding to the most wide-ly studied molecular targets of SARS-CoV-2 viz., spike glycoprotein (S protein), and main pro-tease (Mpro, also referred as chymotrypsin like protease) using molecular docking approaches and correlate the results with reported mechanisms of actions of HCQ. Methods: X-ray crystallographic structures of spike glycoprotein and main protease of SARS-CoV-2 were retrieved from Research Collaboratory for Structural Bioinformatics (RCSB) Protein Data Bank (PDB). The structure of Hydroxychloroquine was retrieved from the PubChem compound database. The binding interactions of the HCQ with target proteins were predicted using C-Docker algorithm, and visualized using Discovery studio visualizer. Results: Data from molecular docking studies showed very strong binding of HCQ to the main pro-tease compared to spike glycoprotein. Conclusion: The antiviral activity of HCQ is attributed to its ability to bind to the main protease compared to surface glycoprotein. Therefore, future studies should focus more on developing a combination agent/strategy for targeting surface glycoprotein and main protease together.

Iron dysregulation in COVID-19 and reciprocal evolution of SARS-CoV-2: Natura nihil frustra facit.

After more than a year of the COVID-19 pandemic, SARS-CoV-2 infection rates with newer variants continue to devastate much of the world. Global healthcare systems are overwhelmed with high positive patient numbers. Silent hypoxia accompanied by rapid deterioration and some cases with septic shock is responsible for COVID-19 mortality in many hospitalized patients. There is an urgent need to further understand the relationships and interplay with human host components during pathogenesis and immune evasion strategies. Currently, acquired immunity through vaccination or prior infection usually provides sufficient protection against the emerging variants of SARS-CoV-2 except Omicron variant requiring recent booster. New strains have shown higher viral loads and greater transmissibility with more severe disease presentations. Notably, COVID-19 has a peculiar prognosis in severe patients with iron dysregulation and hypoxia which is still poorly understood. Studies have shown abnormally low serum iron levels in severe infection but a high iron overload in lung fibrotic tissue. Data from our in-silico structural analysis of the spike protein sequence along with host proteolysis processing suggests that the viral spike protein fragment mimics Hepcidin and is resistant to the major human proteases. This functional spike-derived peptide dubbed "Covidin" thus may be intricately involved with host ferroportin binding and internalization leading to dysregulated host iron metabolism. Here, we propose the possible role of this potentially allogenic mimetic hormone corresponding to severe COVID-19 immunopathology and illustrate that this molecular mimicry is responsible for a major pathway associated with severe disease status. Furthermore, through 3D molecular modeling and docking followed by MD simulation validation, we have unraveled the likely role of Covidin in iron dysregulation in COVID-19 patients. Our meta-analysis suggests the Hepcidin mimetic mechanism is highly conserved among its host range as well as among all new variants to date including Omicron. Extensive analysis of current mutations revealed that new variants are becoming alarmingly more resistant to selective human proteases associated with host defense.

Possible mechanistic insights into iron homeostasis role of the action of 4-aminoquinolines (chloroquine/hydroxychloroquine) on COVID-19 (SARS-CoV-2) infection

OBJECTIVE: With the recent direction in drug repurposing, many approved drugs have been evaluated to assess their effect on the coronavirus or SARS-CoV-2 infection (COVID-19). Driving this path, chloroquine (CQ) has been used in the treatment of malaria and hydroxychloroquine (HCQ) in immunomodulatory and anti-thrombotic action. playing a leading role in initial management of the viral infection. MATERIALS AND METHODS: Literature search was done using Google Scholar, PubMed and Scopus database using keywords "chloroquine" "SARS-CoV-2 - "COVID-19" "mechanism of action" and articles of interest were selected providing evidence of the possible role of CQ in viral infection. RESULTS: In a bid to understand how and if CQ and HCQ would exert their anti-viral property, mechanistic exegesis was done to review various proposed mechanisms of action. This revealed the inhibition of viral attachment and entry, inhibition of enveloped glycoprotein, inhibition of the development and proliferation of new viral particles as the way they perform their action. There is an interplay between iron metabolism and homeostasis with COVID-19 infection and viral reproduction. CONCLUSIONS: This study aims to show the functional role of CQ and HCQ, as well as to provide possible mechanistic insight on the role of iron on viral infection. iron starvation and its downstream cellular pathways involving hepcidin and proinflammatory cytokines. The overall aim of providing possible mode of action of CQ and HCQ in the management of COVID-19 infection is exhibited via its anti-viral. anti-inflammatory and anti-thrombotic activities.

Ferritin - from iron, through inflammation and autoimmunity, to COVID-19.

While it took decades to arrive to a conclusion that ferritin is more than an indicator of iron storage level, it took a short period of time through the COVID-19 pandemic to wonder what the reason behind high levels of ferritin in patients with severe COVID-19 might be. Unsurprisingly, acute phase reactant was not a satisfactory explanation. Moreover, the behavior of ferritin in patients with severe COVID-19 and the subsequent high mortality rates in patients with high ferritin levels necessitated further investigations to understand the role of ferritin in the diseases. Ferritin was initially described to accompany various acute infections, both viral and bacterial, indicating an acute response to inflammation. However, with the introduction of the hyperferritinemic syndrome connecting four severe pathological conditions such as adult-onset Still's disease, macrophage activation syndrome, catastrophic antiphospholipid syndrome, and septic shock added another aspect of ferritin where it could have a pathogenetic role rather than an extremely elevated protein only. In fact, suggesting that COVID-19 is a new member in the spectrum of hyperferritinemic syndrome besides the four mentioned conditions could hopefully direct further search on the pathogenetic role of ferritin. Doubtlessly, improving our understanding of those aspects of ferritin would enormously contribute to better coping with severe diseases in terms of treatment and prevention of complications. The origin, history, importance, and the advances of searching the role of ferritin in various pathological and clinical processes are presented hereby in our article. In addition, the implications of ferritin in COVID-19 are addressed.

How Does Mucorales Benefit from the Dysregulated Iron Homeostasis During SARS-CoV-2 Infection?

Mucorales is the cause of mucormycosis, an emerging opportunistic infection in the era of coronavirus disease 2019 (COVID-19) pandemic. Condition of hyperglycemia, diabetes mellitus, and acidosis; dysregulated iron homeostasis in the form of hyperferritinemic syndrome, and high concentration of iron in circulation; and endothelial injury related to abundance glucose regulated protein 78 (GRP78), which are present in severe COVID-19, could favor Mucorales infection. In this short communication, we summarized how the dysregulated iron homeostasis in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection benefits Mucorales.

A Review on Lactoferrin and Central Nervous System Diseases.

Central nervous system (CNS) diseases are currently one of the major health issues around the world. Most CNS disorders are characterized by high oxidative stress levels and intense inflammatory responses in affected tissues. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein, plays a significant role in anti-inflammatory, antibacterial, antiviral, reactive oxygen species (ROS) modulator, antitumor immunity, and anti-apoptotic processes. Previous studies have shown that Lf is abnormally expressed in a variety of neurological diseases, especially neurodegenerative diseases. Recently, the promotion of neurodevelopment and neuroprotection by Lf has attracted widespread attention, and Lf could be exploited both as an active therapeutic agent and drug nanocarrier. However, our understanding of the roles of Lf proteins in the initiation or progression of CNS diseases is limited, especially the roles of Lf in regulating neurogenesis. This review highlights recent advances in the understanding of the major pharmacological effects of Lf in CNS diseases, including neurodegenerative diseases, cerebrovascular disease, developmental delays in children, and brain tumors.

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.

Iron: Innocent bystander or vicious culprit in COVID-19 pathogenesis?

The coronavirus 2 (SARS-CoV-2) pandemic is viciously spreading through the continents with rapidly increasing mortality rates. Current management of COVID-19 is based on the premise that respiratory failure is the leading cause of mortality. However, mounting evidence links accelerated pathogenesis in gravely ill COVID-19 patients to a hyper-inflammatory state involving a cytokine storm. Several components of the heightened inflammatory state were addressed as therapeutic targets. Another key component of the heightened inflammatory state is hyper-ferritinemia which reportedly identifies patients with increased mortality risk. In spite of its strong association with mortality, it is not yet clear if hyper-ferritinemia in COVID-19 patients is merely a systemic marker of disease progression, or a key modulator in disease pathogenesis. Here we address implications of a possible role for hyper-ferritinemia, and altered iron homeostasis in COVID-19 pathogenesis, and potential therapeutic targets in this regard.