While the focus of this piece is in the title, the information here is applicable elsewhere, in many diseases, acute and chronic inflammation, all sorts of infections (especially viral, and respiratory), but above all else, old age. A defining feature of old age is the loss of your redox capacity, the redox system is highly complex and full of contradictions, but in hyper simplified terms is a system to clean your body out of cellular “reactions” and “cellular rust”. The loss of redox capacity affects almost every single cellular function via (loss of and excess of) signaling and reactions, but especially cascade effects.
It is no secret I and many others have voiced since early 2020 regarding the importance of proper antioxidation function in regard to SARS-CoV-2 infection, and many of its secondary, even tertiary after-effects.
How the Competition for Cysteine May Promote Infection of SARS-CoV-2 by Triggering Oxidative Stress
SARS-CoV-2 induces a broad range of clinical manifestations. Besides the main receptor, ACE2, other putative receptors and co-receptors have been described and could become genuinely relevant to explain the different tropism manifested by new variants. In this study, we propose a biochemical model envisaging the competition for cysteine as a key mechanism promoting the infection and the selection of host receptors. The SARS-CoV-2 infection produces ROS and triggers a massive biosynthesis of proteins rich in cysteine; if this amino acid becomes limiting, glutathione levels are depleted and cannot control oxidative stress. Hence, infection succeeds. A receptor should be recognized as a marker of suitable intracellular conditions, namely the full availability of amino acids except for low cysteine. First, we carried out a comparative investigation of SARS-CoV-2 proteins and human ACE2. Then, using hierarchical cluster protein analysis, we searched for similarities between all human proteins and spike produced by the latest variant, Omicron BA.1. We found 32 human proteins very close to spike in terms of amino acid content. Most of these potential SARS-CoV-2 receptors have less cysteine than spike. We suggest that these proteins could signal an intracellular shortage of cysteine, predicting a burst of oxidative stress when used as viral entry mediators.
What the authors propose in this paper is both fascinating and based on observational reality. I would highly recommend you to at the very least read the entire Introduction section of the paper, it is a very good overview of the redox subject. Here are the most important highlights.
What is proposed in this paper isn’t as simple to understand as other papers, but it is both fascinating and observationally true, and using different mechanisms other viruses exploit the same dynamic to enhance their viral replication. What separates the hypothesis proposed from others is this effect here is mediated by many of the virus proteins, not just the Spike even though this protein plays a significant role overall.
Sufficient ROS generation leads to inflammatory signaling, which by using different mechanics will deplete nutrients inside and outside the cells, creating a propitious environment for the replication of a pathogen, and their proposition is not far-fetched, one of the first things one may learn when delving into virology and the molecular mechanisms of viruses is their tendency to infect cells that gives them the best “nutrient pool”, here proposed as cells that have an abundance of the necessary amino acids for exponential viral replication. The second part of their model is the imbalance between ROS and GSH (glutathione), and one way the virus exploits this significant aspect of cellular biology would be by depleting cysteine inside the cell.
Per the author’s own words “To curb glutathione synthesis, Cys must be heavily consumed by other metabolic pathways such as protein synthesis. Cys is particularly abundant in the SARS-CoV-2 protein set. Among all proteins produced by viruses that infect humans, the SARS-CoV-2 spike features the highest cysteine content, especially in the cytoplasmic domain, which is essential for palmitoylation and membrane fusion”, by possessing a heavy presence of cysteine (Cys), the moment the virus replicates, it effectively “steals” your intracellular cysteine.
For my intended purposes, this is enough information to form the overall context, but there is a lot of detailed work and observations in this paper that deserve attention if you are inclined to read it, but a good grasp of cell biology is necessary to get all the nuances. The following paper is even “better”, because it isn’t a proposed model, and as a byproduct, confirms parts of what we just analyzed, indirectly.
SARS-CoV-2 Main Protease Targets Host Selenoproteins and Glutathione Biosynthesis for Knockdown via Proteolysis, Potentially Disrupting the Thioredoxin and Glutaredoxin Redox Cycles
Associations between dietary selenium status and the clinical outcome of many viral infections, including SARS-CoV-2, are well established. Multiple independent studies have documented a significant inverse correlation between selenium status and the incidence and mortality of COVID-19. At the molecular level, SARS-CoV-2 infection has been shown to decrease the expression of certain selenoproteins, both in vitro and in COVID-19 patients.
Using computational methods, our group previously identified a set of six host proteins that contain potential SARS-CoV-2 main protease (Mpro) cleavage sites. Here we show experimentally that Mpro can cleave four of the six predicted target sites, including those from three selenoproteins: thioredoxin reductase 1 (TXNRD1), selenoprotein F, and selenoprotein P, as well as the rate-limiting enzyme in glutathione synthesis, glutamate-cysteine ligase catalytic subunit (GCLC). Cleavage was assessed by incubating recombinant SARS-CoV-2 Mpro with synthetic peptides spanning the proposed cleavage sites, and analyzing the products via UPLC-MS.
Furthermore, upon incubation of a recombinant Sec498Ser mutant of the full TXNRD1 protein with SARS-CoV-2 Mpro, the predicted cleavage was observed, destroying the TXNRD1 C-terminal redox center. Mechanistically, proteolytic knockdown of both TXNRD1 and GCLC is consistent with a viral strategy to inhibit DNA synthesis, conserving the pool of ribonucleotides for increased virion production. Viral infectivity could also be enhanced by GCLC knockdown, given the ability of glutathione to disrupt the structure of the viral spike protein via disulfide bond reduction.T hese findings shed new light on the importance of dietary factors like selenium and glutathione in COVID-19 prevention and treatment.
One of the first micronutrients for which evidence of a significant role in COVID-19 emerged, even within the first months of the pandemic, is the trace element selenium (Se) [9,10,11]. The fact that multiple research groups from different countries studied this question intensely, almost from the outset of the pandemic, is not that surprising in the light of over 40 years of accumulating evidence that has firmly demonstrated links between Se status and the clinical outcome of various viral infections, including HIV-1, coxsackieviruses, hepatitis viruses, hantaviruses, influenza virus, and most recently, SARS-CoV-2, as detailed in many recent reviews [12,13,14,15,16,17,18,19]. The sheer number of new review articles on the role of Se in viral infections, and its significance for COVID-19, reflects the greatest rekindling of interest in this topic in several decades.
To understand how and why selenium fits in a discussion about Glutathione, Cysteine, and antioxidation/redox you first need to learn how it fits into this complex puzzle. Selenium is a major cofactor for glutathione, whenever you read a nutrient or chemical as a “cofactor” it means it is essential for either your body creating what it is a cofactor for, or for the activity of what is a cofactor. Selenoproteins are proteins with selenium and cysteine “together”, they are incredibly important for the overall function and health of cells, especially the ones mentioned here, that are essential for redox activity.
SARS-CoV-2 main protease (Mpro) is widely accepted among researchers of coronaviruses as indispensable for its viral replication, and here using experimental testing, backed by previous research and bioinformatics the authors found that the Mpro can cleave (cut) a few selenoproteins, and some of them are incredibly important as we are about to discuss. The second paragraph has good resources on the role of selenium in viral infections, a very good resource to learn new insights.
In regards to their finds, of all the selenoproteins that are actively disrupted by Mpro, the most remarkable and arguably significant in the “grand scheme” is GCLC. GCLC is a rate-limiting enzyme (rate-limiting serves as a way to keep the balance and “speed” of something) for Glutathione biosynthesis (fancy word for production), and the virus does this by proteolytic degradation, meaning breaking down GCLC before it does its job, this directly negatively impacts the production of Glutathione and its function.
COVID-19 patients have been found to manifest severe GSH deficiency, increased oxidative stress, and oxidant damage relative to uninfected controls [45]. Other authors have pointed out that low GSH levels are characteristic of many comorbid conditions associated with increased severity of COVID-19 [46], and that there are multiple molecular mechanisms by which “GSH depletion may have a fundamental role in COVID-19 pathophysiology” [47]. Quite early in the pandemic, it was presciently suggested by Polonikov that endogenous GSH deficiency was the “most likely cause of serious manifestations and death in COVID-19 patients” [48].
Another important aspect of GSH and the redox system is DNA synthesis.
Disrupting the redox system by targeting important proteins that play paramount roles in its function is not merely an accidental byproduct of the viral infection and proteins interaction, but a direct strategy for survival and replication of the virus. Such disruption explains the substantial role oxidative stress and ROS/inflammation play during and after the infection. And the last highlight is one you should take to heart, the role of Vitamin D on antioxidation and anti-inflammation, and by directly and indirectly increasing the level of the same important proteins Mpro disrupts.
However, our current findings in regard to SARS-CoV-2 are unprecedented, because this is the first time that any virus has been shown to target selenoprotein expression at the protein level, by a direct proteolytic attack. The proteolytic targeting of both TXNRD1 and GCLC, and thus GSH biosynthesis, is consistent with a coordinated two-pronged attack, disrupting both redox cycles required to sustain DNA synthesis, which strongly supports the hypothesis illustrated in Figure 8. Furthermore, the potential for significant disruption of GSH synthesis by SARS-CoV-2 is highly consistent with recent clinical observations showing profound GSH deficits in patients that correlate with the severity of COVID-19 [45,46,47], as well as in infected cells [51]. The virus also benefits from GSH knockdown by inhibiting its role as a disruptor of spike protein RBD structure and binding [54,55]. Taken as a whole, this body of evidence suggests an urgent need for further investigations of GSH repletion or complementation strategies, such as supplementation with GSH precursors like N-acetyl cysteine (NAC), or the more effective combination of NAC plus glycine [45,46], γ-glutamyl cysteine (GGC, the product of GCLC), or the GSH mimic α-lipoic acid, as potentially useful symptomatic treatments for COVID-19.
Lastly, one inescapable conclusion in regard to SARS-CoV-2 is that, of any virus known to date, it is in a class by itself as far as its innovations in the perturbation of host Se and selenoprotein-based mechanisms. It certainly gives the appearance of an escalation in the arms race between viral replication and the defensive host mechanisms of which selenoproteins are an essential part.
The closing remarks of this magnificent paper speak for themselves. The virus attacks your redox ability by disrupting even the “backup” system, by depleting and starving your body of Glutathione, it directly impedes your body from disrupting the Spike Protein (certain points of the Spike are fragile towards certain chemical reactions), it helps its own viral replication cycle (RNA synthesis), creating a susceptible environment to its continuous deleterious health effects. This disruption is potentialized by many other comorbidities and conditions, in a myriad of complex interactions these conditions create a perpetual loop of “draining” the necessary nutrients for proper Glutathione synthesis and redox function, precisely why certain types of diseases (Diabetes being the easiest one to observe) possessing a disproportional weight in the outcomes of the infection.
Obviously, I wouldn’t end this piece here, by merely pointing out the remarkable finding of both papers and their propositions. Here is where things get… well… interesting. For reasons I rather not get into here, I spend a considerable (hundreds of hours) time researching protein folding back in 2021, and given my harsh, acidic personality, I became rather annoying when it came to protein misfolding. You can personally scour hundreds of papers on protein misfolding, amyloid, tau, prion disease, and you will always find a common denominator lost somewhere in many of these papers, the same dynamic repeats over, and over.
Low intracellular glutathione, cysteine deficiency.
There is a lot of complexity and intricacies in regards to proteinopathies, diseases caused by the improper folding (shape) and accumulation of said proteins, yet at the core, much of the effects are byproducts of cells being overwhelmed by different biochemical reactions, and draining your body of nutrients (nutrient pool is the term often used). Selenium itself may prevent and treat Alzheimer’s, mild cognitive impairment, can help with Parkinson’s, and its nanoparticles are efficient in Huntington’s therapy, there is quite a discussion, with good evidence that it helps deal with Epstein Barr and its associated damage (thyroid disease).
Selenium also plays a role in regulating iron dyshomeostasis. Why is this important ? When your redox system doesn’t work properly, one of the “side-effects” will be the loss of capacity to keep iron and many iron-based reactions in check, the loss of proper levels of selenium will directly influence the function of Glutathione, the main player on keeping ferroptosis in check. (To my reader that asked me about a ferroptosis post, I do remember, I will get to it soon, I promise) This remarkable paper proposes without selenium development of complex nervous system in mammals wouldn’t be possible precisely because of ferroptosis. Ferroptosis play a disproportionally significant role in neurodegeneration, and many, many other diseases.
Similar literature can be found in regard to NAC (a literal glutathione precursor), I have written so much about NAC that I will merely link a portion of it below.
Why these dynamics are important ? Because of the following.
The mRNA vaccines literally drain the body of GSH and cause a massive surge in ROS
Transforming the mRNA into protein is such a nocive process that it will feed disease rather
ROS is one of the main causes of the myriad of damage we see
As such, it is the main contributor to brain inflammation and dysfunction
As such, after each infection, after each viral reactivation, your body is drained of the necessary nutrients to deal with the kaleidoscopic changes that each new pathogen inflicts upon each individual, with certain infections starving the body out of the most important nutrients to deal with the long-term effects of said infections. And the vaccinated start this marathon a lot far behind the rest of society.
Not possessing adequate levels of antioxidants, especially Glutathione will lead to a couple of dozen cascade effects, which in turn will create different molecular loops, birthing what I and a couple of friends refer to as “doom loops”, endless loops that feed and accelerate dozens of pathologies. Here lies the primary part of SARS-CoV-2 as The Great Accelerator.
Since quite a few readers asked me, here is my suggestion on when, and how to use specific supplements.
Given the last 3 years I recommend taking selenium either as a multivitamin or standalone daily, regardless of your health status or diet, but the higher your carbohydrate intake, the more selenium you will need
One could either choose Liposomal Glutathione or NAC+Glycine (It is literally in the name of Glutathione - γ-glutamyl>cysteinylglycine<)
When to take it → If you have chronic inflammation of any level, chronic diseases, diabetes, or chronic infections most likely you need 500-100 mg of Glutathione 1200 to 1800 mg of NAC, the same amount of Glycine for a good few weeks, a healthy person with good diet doesn’t need such aggresive supplementation
The older you are the higher your dosage, you can easily supplement GRAMS per day
Another choice for anyone healthy or any level of ill is cycling, meaning spending X amount of weeks taking the dosage you are comfortable with, X amount of weeks off, supplements are not drugs, they take time to have any perceptible effect, therefore a minimum of 4 weeks on are necessary
Not a suggestion but a very strong worded recommendation is taking all of the aforementioned supplements after each and Every. Single. Respiratory. Infection. One could use the same approach towards other diseases, but after each respiratory infection is almost a must. SARS-CoV-2 has already been linked with the development and acceleration of neurodegenerative diseases, the Spanish Flu had the same effect, and many other pathogens will soon follow, with pandemic ones being more pertinent to these dynamics.
As I wrote recently, if all fails, the body has very few other ways to deal with unwanted anything inside your body. Neurodegeneration development and acceleration are a byproduct of such “last resort”. This will also help in the function of your immune system, and protect many from one of the clearest “aftereffects” of this pandemic. Inflammaging (I highly recommend anyone to read my substacks regarding the subject again, you definitely should take it to heart).
If there is interest I can expand on the subject of antioxidation by itself too.
By the way, a ketogenic or low-carbohydrate diet can achieve a lot of the benefits discussed here, via other mechanisms and should be your primary goal if possible
My gratitude to anyone who decided to support this Substack, thank you ! And anyone who shares it !
Yes actually only need 1 Brazil nut a day,....but who can eat only 1 Brazil nut😳
I supplement regularly NAC, magnesium, vit B3, C & D, zinc etc. But I have the weird tendency when I get slightly sick I stop everything. I feel extremely sick by supplementing anything. Also in general food. During sickness I think I'm in a fasting mood and basically just drinking huge amount of water.
Then after the sickness is over I have a craving to go back for supplements. I tried pushing through with antioxidants during sickness but it just doesn't work for me.