The link between inflammation, PAH etc, autoimmune disorders & cancers: Reactive Oxygen Species
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Any extracts used in the following article are for non commercial research and educational purposes only and may be subject to copyright from their respective owners.
Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response.
SARS-CoV-2 spike promotes inflammation and apoptosis through autophagy by ROS-suppressed PI3K/AKT/mTOR signaling (2021)
Abstract
Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection-induced inflammatory responses are largely responsible for the death of novel coronavirus disease 2019 (COVID-19) patients. However, the mechanism by which SARS-CoV-2 triggers inflammatory responses remains unclear. Here, we aimed to explore the regulatory role of SARS-CoV-2 spike protein in infected cells and attempted to elucidate the molecular mechanism of SARS-CoV-2-induced inflammation.
Methods: SARS-CoV-2 spike pseudovirions (SCV-2-S) were generated using the spike-expressing virus packaging system. Western blot, mCherry-GFP-LC3 labeling, immunofluorescence, and RNA-seq were performed to examine the regulatory mechanism of SCV-2-S in autophagic response. The effects of SCV-2-S on apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Western blot, and flow cytometry analysis. Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the mechanism of SCV-2-S in inflammatory responses.
Results: Angiotensin-converting enzyme 2 (ACE2)-mediated SCV-2-S infection induced autophagy and apoptosis in human bronchial epithelial and microvascular endothelial cells. Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response. Ultimately, SCV-2-S-induced autophagy triggered inflammatory responses and apoptosis in infected cells. These findings not only improve our understanding of the mechanism underlying SARS-CoV-2 infection-induced pathogenic inflammation but also have important implications for developing anti-inflammatory therapies, such as ROS and autophagy inhibitors, for COVID-19 patients.
Angiotensin-(1-7)-ACE2 attenuates reactive oxygen species formation to Angiotensin II within the cell nucleus (2009)
Abstract
The angiotensin type 1 receptor (AT1R) is highly expressed on renal nuclei and stimulates reactive oxygen species (ROS). It is not known whether other functional components of the angiotensin (Ang) system regulate the nuclear Ang II-AT1R-ROS pathway. Therefore, we examined the expression of Ang receptors in nuclei isolated from the kidneys of young adult (1.5 years) and older adult (3â5 years) sheep. Binding studies in renal nuclei revealed the AT2R as the predominant receptor subtype (~80%) in young sheep, with the AT7R (Mas protein) and AT1R antagonists competing for 52% and 25% of nuclear sites, respectively. Conversely, in older sheep, the AT1R accounted for ~85% of nuclear sites while the AT2R and AT7R subtypes comprised ~20% of remaining sites. Ang II increased nuclear ROS to a greater extent in older (97 ± 22%; n = 6) versus young animals (7 ± 2%; p = 0.01, n = 4) and this was abolished by an AT1R antagonist. The AT7R antagonist D-Ala7-Ang-(1-7) increased ROS formation to Ang II approximately two-fold (174 ± 5% vs. 97 ± 22%; p<0.05) in older adults. Immunoblots of renal nuclei revealed protein bands for the AT7R and angiotensin converting enzyme (ACE2) which metabolizes Ang II to Ang-(1-7). The ACE2 inhibitor MLN4760 also exacerbated the Ang II-dependent formation of ROS (156 ± 15%) and abolished the generation of Ang-(1-7) from Ang II. We conclude that an ACE2-Ang-(1-7)-AT7R pathway modulates Ang II-dependent ROS formation within the nucleus, providing a unique protective mechanism against oxidative stress and cell damage.
It is well-established that reactive oxygen species (ROS) play an important role as signaling molecules in a variety of cellular responses 1. Sustained perturbations in redox homeostasis can result in oxidative stress leading to cardiovascular damage and cellular injury. Angiotensin (Ang) II stimulates the generation of ROS through the AT1 receptor isoform 2. Blockade of the renin-angiotensin aldosterone system (RAAS) either by selective AT1 receptor antagonists (ARBs) or inhibition of the formation of Ang II by angiotensin converting enzyme (ACE) inhibitors is the leading therapeutic approach to lower blood pressure and reduce tissue injury in various cardiovascular pathologies. A wealth of experimental evidence reveals that inhibition of the Ang II-generating axis of the RAAS is associated with a reduction in oxidative stress within the kidney and other tissues 3-6.
Angiotensin IIâInduced Reactive Oxygen Species and the Kidney (2007)
Abstract
Angiotensin II (AngII) is an important mediator in renal injury. Accumulating evidence suggests that AngII stimulates intracellular formation of reactive oxygen species (ROS) such as the superoxide anion and hydrogen peroxide. AngII activates several subunits of the membrane-bound multicomponent NAD(P)H oxidase and also increases ROS formation in the mitochondria. Some of these effects may be induced by aldosterone and not directly by AngII. The superoxide anion and hydrogen peroxide influence other downstream signaling pathways, such as transcription factors, tyrosine kinases/phosphatases, ion channels, and mitogen-activated protein kinases. Through these signaling pathways, ROS have distinct functional effects on renal cells. They are transducers of cell growth, apoptosis, and cell migration and affect expression of inflammatory and extracellular matrix genes. For example, AngII-mediated expression of p27Kip1, a cell-cycle regulatory protein, and induction of tubular hypertrophy depend on the generation of ROS. The effects of ROS generated within different renal cells ultimately depend on the locally generated concentrations and the balance of pro- and antioxidant pathways. Although the concept that AngII mediates oxidative stress in the kidney has been validated in experimental models, the exact role is still incompletely understood in human renal diseases.
The renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in regulating physiologic and pathophysiologic processes in the kidney.1 Although different components of the RAAS, such as renin, aldosterone, and various angiotensin fragments, can initiate renal impairment on their own, angiotensin II (AngII) is the primary effector of this system. AngII was originally identified as a vasoconstrictor and potent stimulus of aldosterone release from the suprarenal glands and also has been implicated in the regulation of glomerular filtration and tubular transport. Intensive research in the past 15 yr has provided convincing evidence that AngII is a key contributor to progression of renal disease by stimulating growth, inflammation, and fibrosis of the kidney.2
AngII binds to specific receptors to mediate its particular effects. The angiotensin type 1 (AT1) and type 2 (AT2) receptors are the best characterized receptors on a molecular level, but additional types may exist. Most of the known physiologic and pathophysiologic effects of AngII are transduced by the AT1 receptor, a 359âamino acid protein that belongs to the seven-membrane superfamily of G-proteinâassociated receptors.3 After the binding of AngII to the AT1 receptors, a series of signaling cascades is activated. Although traditionally divided into G-proteinâand nonâG-proteinârelated signaling, there are so many interactions between these subgroups of AngII-induced signaling pathways that a strict distinction becomes difficult. An example of a G-proteinâdependent pathway is activation of phospholipase C with the subsequent production of inositol 1,4,5-phosphate and diacylglycerol. NonâG-protein pathways induced by AngII are phosphorylation and the activation of various tyrosine kinases. AngII is an important mediator of oxidative stress, and reactive oxygen species (ROS) induced by AngII are chief signal intermediates in several signal transduction pathways involved in renal pathophysiology.4 Moreover, AngII-induced ROS are important for renal growth processes, inflammation, and fibrosis.5 This brief review highlights how AngII stimulates ROS formation and how ROS contribute to kidney injury.
What Are ROS?
ROS are composed of a series of oxygen intermediates, including the free radical superoxide anion (·O2â), the nonradical hydrogen peroxide (H2O2), the highly reactive hydroxyl free radical (·OH), peroxynitrite (ONOOâ), and singlet oxygen (1O2), in which one of the electrons is raised to an orbital of higher energy with an inversion of spin. Some of the pathways for generation and metabolism of ROS are shown in Figure 1. The original source is O2, which is univalently reduced to form ·O2â by multiple enzymatic pathways (Figure 1). ·O2â is unstable in aqueous solutions with a half-life of seconds.6â10 It is catalyzed into H2O2 by superoxide dismutase. This relatively weak oxidant holds a central position in the further metabolism to other ROS. H2O2 can oxidize chloride to form the reactive hypochlorous acid (HOCl) in cells that express the enzyme myeloperoxidase. HOCl may further react with O2â to form the hydroxyl free radical (HOCl + ·O2â â ·OH + O2 + Clâ). Alternatively, hypochlorite (OClâ) can further interact with H2O2 to produce singlet oxygen (OClâ + H2O2 â 1O2 + H2O + Clâ). ·OH can also be formed from H2O2 and ·O2â by an iron-catalyzed reaction, the so-called Haber-Weiss reaction.6,10 It is interesting that the Haber-Weiss reaction is also implicated in the generation of 1O2.
Monitoring Serum Spike Protein with Disposable Photonic Biosensors Following SARS-CoV-2 Vaccination (2021)
Representative peak traces for chips sensing the presence of spike protein in unvaccinated (a,b) and recently vaccinated (c,d) subjects and anti-spike antibodies after the second dose. (e,f). (a,c,e) Each chip has a control (red) and capture (i.e., analyte-specific, blue) ring, whose resonance peaks are tracked over time. (b,d,f) The control ring is subtracted from the capture ring to give the relative shift, which is indicative of specific analyte binding. The relative shift at 3 min is what was recorded to compare between assays.
The link between inflammation, PAH etc, autoimmune disorders & cancers: Reactive Oxygen Species
The link between inflammation, PAH etc, autoimmune disorders & cancers: Reactive Oxygen Species
The link between inflammation, PAH etc, autoimmune disorders & cancers: Reactive Oxygen Species
Any extracts used in the following article are for non commercial research and educational purposes only and may be subject to copyright from their respective owners.
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In a nutshell:
Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response.
SARS-CoV-2 spike promotes inflammation and apoptosis through autophagy by ROS-suppressed PI3K/AKT/mTOR signaling (2021)
Abstract
Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection-induced inflammatory responses are largely responsible for the death of novel coronavirus disease 2019 (COVID-19) patients. However, the mechanism by which SARS-CoV-2 triggers inflammatory responses remains unclear. Here, we aimed to explore the regulatory role of SARS-CoV-2 spike protein in infected cells and attempted to elucidate the molecular mechanism of SARS-CoV-2-induced inflammation.
Methods: SARS-CoV-2 spike pseudovirions (SCV-2-S) were generated using the spike-expressing virus packaging system. Western blot, mCherry-GFP-LC3 labeling, immunofluorescence, and RNA-seq were performed to examine the regulatory mechanism of SCV-2-S in autophagic response. The effects of SCV-2-S on apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Western blot, and flow cytometry analysis. Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the mechanism of SCV-2-S in inflammatory responses.
Results: Angiotensin-converting enzyme 2 (ACE2)-mediated SCV-2-S infection induced autophagy and apoptosis in human bronchial epithelial and microvascular endothelial cells. Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response. Ultimately, SCV-2-S-induced autophagy triggered inflammatory responses and apoptosis in infected cells. These findings not only improve our understanding of the mechanism underlying SARS-CoV-2 infection-induced pathogenic inflammation but also have important implications for developing anti-inflammatory therapies, such as ROS and autophagy inhibitors, for COVID-19 patients.
Keywords: Apoptosis; Autophagy; Inflammation; Reactive oxygen species; SARS-CoV-2.
https://pubmed.ncbi.nlm.nih.gov/34461258/
# Spike protein binds with ACE2 #
Angiotensin-(1-7)-ACE2 attenuates reactive oxygen species formation to Angiotensin II within the cell nucleus (2009)
Abstract
The angiotensin type 1 receptor (AT1R) is highly expressed on renal nuclei and stimulates reactive oxygen species (ROS). It is not known whether other functional components of the angiotensin (Ang) system regulate the nuclear Ang II-AT1R-ROS pathway. Therefore, we examined the expression of Ang receptors in nuclei isolated from the kidneys of young adult (1.5 years) and older adult (3â5 years) sheep. Binding studies in renal nuclei revealed the AT2R as the predominant receptor subtype (~80%) in young sheep, with the AT7R (Mas protein) and AT1R antagonists competing for 52% and 25% of nuclear sites, respectively. Conversely, in older sheep, the AT1R accounted for ~85% of nuclear sites while the AT2R and AT7R subtypes comprised ~20% of remaining sites. Ang II increased nuclear ROS to a greater extent in older (97 ± 22%; n = 6) versus young animals (7 ± 2%; p = 0.01, n = 4) and this was abolished by an AT1R antagonist. The AT7R antagonist D-Ala7-Ang-(1-7) increased ROS formation to Ang II approximately two-fold (174 ± 5% vs. 97 ± 22%; p<0.05) in older adults. Immunoblots of renal nuclei revealed protein bands for the AT7R and angiotensin converting enzyme (ACE2) which metabolizes Ang II to Ang-(1-7). The ACE2 inhibitor MLN4760 also exacerbated the Ang II-dependent formation of ROS (156 ± 15%) and abolished the generation of Ang-(1-7) from Ang II. We conclude that an ACE2-Ang-(1-7)-AT7R pathway modulates Ang II-dependent ROS formation within the nucleus, providing a unique protective mechanism against oxidative stress and cell damage.
Keywords: Angiotensin, Reactive Oxygen Species, kidney, angiotensin â (1-7) receptor, intracellular RAS
INTRODUCTION
It is well-established that reactive oxygen species (ROS) play an important role as signaling molecules in a variety of cellular responses 1. Sustained perturbations in redox homeostasis can result in oxidative stress leading to cardiovascular damage and cellular injury. Angiotensin (Ang) II stimulates the generation of ROS through the AT1 receptor isoform 2. Blockade of the renin-angiotensin aldosterone system (RAAS) either by selective AT1 receptor antagonists (ARBs) or inhibition of the formation of Ang II by angiotensin converting enzyme (ACE) inhibitors is the leading therapeutic approach to lower blood pressure and reduce tissue injury in various cardiovascular pathologies. A wealth of experimental evidence reveals that inhibition of the Ang II-generating axis of the RAAS is associated with a reduction in oxidative stress within the kidney and other tissues 3-6.
Full paper:
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2821807/
Angiotensin IIâInduced Reactive Oxygen Species and the Kidney (2007)
Abstract
Angiotensin II (AngII) is an important mediator in renal injury. Accumulating evidence suggests that AngII stimulates intracellular formation of reactive oxygen species (ROS) such as the superoxide anion and hydrogen peroxide. AngII activates several subunits of the membrane-bound multicomponent NAD(P)H oxidase and also increases ROS formation in the mitochondria. Some of these effects may be induced by aldosterone and not directly by AngII. The superoxide anion and hydrogen peroxide influence other downstream signaling pathways, such as transcription factors, tyrosine kinases/phosphatases, ion channels, and mitogen-activated protein kinases. Through these signaling pathways, ROS have distinct functional effects on renal cells. They are transducers of cell growth, apoptosis, and cell migration and affect expression of inflammatory and extracellular matrix genes. For example, AngII-mediated expression of p27Kip1, a cell-cycle regulatory protein, and induction of tubular hypertrophy depend on the generation of ROS. The effects of ROS generated within different renal cells ultimately depend on the locally generated concentrations and the balance of pro- and antioxidant pathways. Although the concept that AngII mediates oxidative stress in the kidney has been validated in experimental models, the exact role is still incompletely understood in human renal diseases.
The renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in regulating physiologic and pathophysiologic processes in the kidney.1 Although different components of the RAAS, such as renin, aldosterone, and various angiotensin fragments, can initiate renal impairment on their own, angiotensin II (AngII) is the primary effector of this system. AngII was originally identified as a vasoconstrictor and potent stimulus of aldosterone release from the suprarenal glands and also has been implicated in the regulation of glomerular filtration and tubular transport. Intensive research in the past 15 yr has provided convincing evidence that AngII is a key contributor to progression of renal disease by stimulating growth, inflammation, and fibrosis of the kidney.2
AngII binds to specific receptors to mediate its particular effects. The angiotensin type 1 (AT1) and type 2 (AT2) receptors are the best characterized receptors on a molecular level, but additional types may exist. Most of the known physiologic and pathophysiologic effects of AngII are transduced by the AT1 receptor, a 359âamino acid protein that belongs to the seven-membrane superfamily of G-proteinâassociated receptors.3 After the binding of AngII to the AT1 receptors, a series of signaling cascades is activated. Although traditionally divided into G-proteinâand nonâG-proteinârelated signaling, there are so many interactions between these subgroups of AngII-induced signaling pathways that a strict distinction becomes difficult. An example of a G-proteinâdependent pathway is activation of phospholipase C with the subsequent production of inositol 1,4,5-phosphate and diacylglycerol. NonâG-protein pathways induced by AngII are phosphorylation and the activation of various tyrosine kinases. AngII is an important mediator of oxidative stress, and reactive oxygen species (ROS) induced by AngII are chief signal intermediates in several signal transduction pathways involved in renal pathophysiology.4 Moreover, AngII-induced ROS are important for renal growth processes, inflammation, and fibrosis.5 This brief review highlights how AngII stimulates ROS formation and how ROS contribute to kidney injury.
What Are ROS?
ROS are composed of a series of oxygen intermediates, including the free radical superoxide anion (·O2â), the nonradical hydrogen peroxide (H2O2), the highly reactive hydroxyl free radical (·OH), peroxynitrite (ONOOâ), and singlet oxygen (1O2), in which one of the electrons is raised to an orbital of higher energy with an inversion of spin. Some of the pathways for generation and metabolism of ROS are shown in Figure 1. The original source is O2, which is univalently reduced to form ·O2â by multiple enzymatic pathways (Figure 1). ·O2â is unstable in aqueous solutions with a half-life of seconds.6â10 It is catalyzed into H2O2 by superoxide dismutase. This relatively weak oxidant holds a central position in the further metabolism to other ROS. H2O2 can oxidize chloride to form the reactive hypochlorous acid (HOCl) in cells that express the enzyme myeloperoxidase. HOCl may further react with O2â to form the hydroxyl free radical (HOCl + ·O2â â ·OH + O2 + Clâ). Alternatively, hypochlorite (OClâ) can further interact with H2O2 to produce singlet oxygen (OClâ + H2O2 â 1O2 + H2O + Clâ). ·OH can also be formed from H2O2 and ·O2â by an iron-catalyzed reaction, the so-called Haber-Weiss reaction.6,10 It is interesting that the Haber-Weiss reaction is also implicated in the generation of 1O2.
Full paper:
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2821807/
Walter is 100% correct, it's the ROS equivalent to recieving a large dose of ionising radiation, and the damage takes milliseconds:
https://twitter.com/Parsifaler/status/1500925513984057348?s=19
Monitoring Serum Spike Protein with Disposable Photonic Biosensors Following SARS-CoV-2 Vaccination (2021)
Representative peak traces for chips sensing the presence of spike protein in unvaccinated (a,b) and recently vaccinated (c,d) subjects and anti-spike antibodies after the second dose. (e,f). (a,c,e) Each chip has a control (red) and capture (i.e., analyte-specific, blue) ring, whose resonance peaks are tracked over time. (b,d,f) The control ring is subtracted from the capture ring to give the relative shift, which is indicative of specific analyte binding. The relative shift at 3 min is what was recorded to compare between assays.
Full paper:
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8434114/
Radiation induced acute respiratory syndrome is induced with the equivalent to 2000 millisieverts, or around 20,000 X-rays.
The recommended safe **lifetime** limit is around 10,000 X-raysâŠ
We need spike protein exposure limits as per with x-rays and ionising radiation, not exposure mandates.
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