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Nathan Goodyear

Elevated Muscle TLR4 Expression and Metabolic Endotoxemia in Human Aging - 0 views

www.ncbi.nlm.nih.gov/...PMC4311182

LPS Toll-like receptors toll like receptors TLR-4 metabolic endotoxemia TLR4

shared by Nathan Goodyear on 24 Jan 22 - No Cached
  • Nathan Goodyear on 24 Jan 22
     
    Not a direct cause and effect, but a clear associated between metabolic endotoxemia and increase in TLR4
Nathan Goodyear

NETosis and Neutrophil Extracellular Traps in COVID-19: Immunothrombosis and Beyond - PMC - 0 views

www.ncbi.nlm.nih.gov/...PMC8924116

cancer NETosis SARS-CoV-2 COVID COVID-19 COVID19 platelets

shared by Nathan Goodyear on 18 Apr 23 - No Cached
  • Pneumonia is a typical symptom of COVID-19 infection, while acute respiratory distress syndrome (ARDS) and multiple organ failure are common in severe COVID-19 patients
  • NETs are important for preventing pathogen invasion, their excessive formation can result in a slew of negative consequences, such as autoimmune inflammation and tissue damage
  • SARS-CoV-2 infection has also been linked to increased neutrophil-to-lymphocyte ratios, which is associated with disease severity and clinical prognosis
  • ...40 more annotations...
  • NETosis is a special form of programmed cell death in neutrophils, which is characterized by the extrusion of DNA, histones, and antimicrobial proteins in a web-like structure known as neutrophil extracellular traps (NETs)
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      Definition
  • increased generation of reactive oxygen species (ROS) is a crucial intracellular process that causes NETosis
  • Another indirect route of SARS-CoV-2-induced NET production is platelet activation
  • When NETs are activated in the circulation, they can also induce hypercoagulability and thrombosis
  • In COVID-19, major NET protein cargos of NETs (i.e., NE, MPO, and histones) are significantly elevated.
  • SARS-CoV-2 can also infect host cells through noncanonical receptors such as C-type lectin receptors
  • Immunopathological manifestations, including cytokine storms and impaired adaptive immunity, are the primary drivers behind COVID-19, with neutrophil infiltration being suggested as a significant cause
  • NETosis and NETs are increasingly recognized as causes of vascular injury
  • SARS-CoV-2 and its components (e.g., spike proteins and viral RNA) attach to platelets and increase their activation and aggregation in COVID-19, resulting in vascular injury and thrombosis, both of which are linked to NET formation
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      Connects SARS-CoV-2 to TLR on Platelets to NETosis to metastasis.
  • NET formation may be caused by activated platelets rather than SARS-CoV-2 itself
  • NETosis, leading to aberrant immunity such as cytokine storms, autoimmune disorders, and immunosuppression.
  • early bacterial coinfections were more prevalent in COVID-19 patients than those infected with other viruses
  • NETosis and NETs may also have a role in the development of post COVID-19 syndromes, including lung fibrosis, neurological disorders, tumor growth, and worsening of concomitant disease
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      NETosis-> tumor growth
  • NETs and other by-products of NETosis have been shown to act as direct inflammation amplifiers. Hyperinflammation
  • “cytokine storm”
  • SARS-CoV-2 drives NETosis and NET formation to allow for the release of free DNA and by-products (e.g., elastases and histones). This may trigger surrounding macrophages and endothelial cells to secrete excessive proinflammatory cytokines and chemokines, which, in turn, enhance NET formation and form a positive feedback of cytokine storms in COVID-19
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      Cycle of hyperinflammation
  • NET release enables self-antigen exposure and autoantibody production, thereby increasing the autoinflammatory response
  • patients with COVID-19 who have higher anti-NET antibodies are more likely to be detected with positive autoantibodies [e.g., antinuclear antibodies (ANA) and anti-neutrophil cytoplasmic antibodies (ANCA)]
  • COVID-19 NETs may act as potential inducers for autoimmune responses
  • have weakened adaptive immunity as well as a high level of inflammation
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      Immunomodulation
  • tumor-associated NETosis and NETs promote an immunosuppressive environment in which anti-tumor immunity is compromised
  • NETs have also been shown to enhance macrophage pyroptosis in sepsis
  • facilitating an immunosuppressive microenvironment
  • persistent immunosuppression may result in bacterial co-infection or secondary infection
  • can enhance this process by interacting with neutrophils through toll-like receptor 4 (TLR4), platelet factor 4 (PF4), and extracellular vesicle-dependent processes
  • NET-induced immunosuppression in COVID-19 in the context of co-existing bacterial infection
  • Following initial onset of COVID-19, an estimated 50% or more of COVID-19 survivors may develop multi-organ problems (e.g., pulmonary dysfunction and neurologic impairment) or have worsening concomitant chronic illness
  • NETs in the bronchoalveolar lavage fluid of severe COVID-19 patients cause EMT in lung epithelial cells
  • decreased E-cadherin (an epithelial marker) expression
    • Nathan Goodyear
      Nathan Goodyear on 23 Apr 23
       
      Leads to emt
  • COVID-19 also has a long-term influence on tumor progression
  • Patients with tumors have been shown to be more vulnerable to SARS-CoV-2 infection and subsequent development of severe COVID-19
  • patients who have recovered from COVID-19 may have an increased risk of developing cancer or of cancer progression and metastasis
  • awaken cancer cells
  • NETs have been shown to change the tumor microenvironment
  • enhance tumor progression and metastasis
  • vitamin C has been tested in phase 2 clinical trials aimed at reducing COVID-19-associated mortality by reducing excessive activation of the inflammatory response
  • vitamin C is an antioxidant that significantly attenuates PMA-induced NETosis in healthy neutrophils by scavenging ROS
  • vitamin C may also inhibit NETosis and NET production in COVID-19
  • Metformin
  • Vitamin C
  • Nathan Goodyear on 18 Apr 23
     
    NETosis intimately involved in progressive COVID, long COVID, autoimmunity, and cancer
Nathan Goodyear

Minireview: Inflammation and Obesity Pathogenesis: The Hypothalamus Heats Up - 0 views

endo.endojournals.org/...4109.full

inflammation obesity overweight hypothalamus HPA

shared by Nathan Goodyear on 04 Oct 12 - No Cached
  • Leptin, secreted by adipocytes in proportion to body fat mass
  • The saturated fatty acid palmitate (16:0) induces NF-κB signaling through a TLR4-dependent mechanism
  • 18:0 (stearic) and longer saturated fatty acids as well as linolenic acid (18:3) increased proinflammatory cytokines, ER stress markers, and TLR4 activation
  • ...6 more annotations...
  • (SOCS)-3. A member of a protein family originally characterized as negative feedback regulators of inflammation (13, 37), SOCS3 inhibits insulin and leptin signaling
  • IKKβ signaling in discrete neuronal subsets appears to be required for both hypothalamic inflammation and excess weight gain to occur during HF feeding
  • the paradoxical observation that hyperphagia and weight gain occur when hypothalamic inflammation is induced by HF feeding, yet when it occurs in response to systemic or local inflammatory processes (e.g. administration of endotoxin), anorexia and weight loss are the rule
  • , serves as a circulating signal of energy stores in part by providing feedback inhibition of hypothalamic orexigenic pathways [e.g. neurons that express neuropeptide Y and agouti-related peptide (AgRP)]
  • and stimulating anorexigenic neurons
  • signals from Toll-like receptors (TLRs), evolutionarily conserved pattern recognition molecules critical for detecting pathogens, amplified through signaling intermediates such as MyD88 activate the inhibitor of κB-kinase-β (IKKβ)/nuclear factor-κB (NF-κB), c-Jun N-terminal kinase (Jnk) and other intracellular inflammatory signals in response to stimulation by circulating saturated fatty acids
  • Nathan Goodyear on 04 Oct 12
     
    great read on the current understanding of how obesity and resultant inflammation disrupts hypothalamic function.
Nathan Goodyear

Inflammation and insulin resistance 10.1016/j.febslet.2007.11.057 : FEBS Letters | Scie... - 0 views

www.sciencedirect.com/...S0014579307012082

inflammation insulin resistance IR PPAR TNF-alpha IL-6 IL-10 IL-1Beta JNK GLT-4 Resistin adiponectin Gherlin NF-kapppB iNOS lkkb obesity TLR-4

shared by Nathan Goodyear on 10 Jan 12 - No Cached
  • A subsequent study by Yuan et al. showed that Tnf treatment of 3T3L1 adipocytes induces insulin resistance and that this could be prevented by pretreatment of cells with aspirin
  • Activation of the Tnf receptor results in stimulation of NFκB signaling via Ikkb
  • Insulin is a pleiotropic hormone
  • ...25 more annotations...
  • the percentage of macrophages in a given adipose tissue depot is positively correlated with adiposity and adipocyte size
  • Il-10 is an anti-inflammatory cytokine produced by macrophages and lymphocytes
  • Il-10 exerts its anti-inflammatory activity by inhibiting Tnf-induced NFκB activation by reducing IKK activity [38]
  • adipose tissue macrophages are responsible for nearly all adipose tissue Tnf expression and a significant portion of Nos2 and Il6 expression
  • One theory holds that the expansion of adipose tissue leads to adipocyte hypertrophy and hyperplasia and that large adipocytes outstrip the local oxygen supply leading to cell autonomous hypoxia with activation of cellular stress pathways
  • The use of the anti-inflammatory compounds, salicylate and its derivative aspirin, for treating symptoms of T2DM dates back over 100 years
  • elevated levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin (IL-8) have all been reported in various diabetic and insulin resistant states
  • overnutrition and obesity are often accompanied by elevations in tissue and circulating FFA concentrations, and saturated FFAs can directly activate pro-inflammatory responses
  • Adipokines such as resistin, leptin and adiponectin, which are secreted by adipocytes, can also affect inflammation and insulin sensitivity
  • In skeletal muscle insulin promotes glucose uptake by stimulating translocation of the GLUT4 glucose transporter
  • macrophages are also capable of undergoing a phenotypic switch from an M1 state, which was defined as the “classically activated” pro-inflammatory macrophage, to the M2 state or the “alternatively activated” non-inflammatory cell
  • saturated fatty acids are the most potent inducers of this inflammatory response
  • Several inducers of insulin resistance, including FFAs, pro-inflammatory cytokines and oxidative stress, activate the expression of Nos2, the gene that encodes iNOS (reviewed in [33]
  • Adipose tissue insulin signaling results in decreased hormone sensitive lipase activity and this anti-lipolytic effect inhibits free fatty acid (FFA) efflux out of adipocytes.
  • In the liver, insulin inhibits the expression of key gluconeogenic enzymes and, therefore, insulin resistance in liver leads to elevated hepatic glucose production
  • elevated JNK activity in liver, adipose tissue and skeletal muscle of obese insulin resistant mice, and knockout of Jnk1 (Jnk1−/−) leads to amelioration of insulin resistance in high fat diet
  • Adipose tissue from obese mice contains proportionately more M1 macrophages, whereas, lean adipose tissue contains more M2 macrophages, and increased M1 content positively correlates with inflammation, macrophage infiltration and insulin resistance
  • C-reactive protein (CRP)
  • these studies highlight the possibility that increased iNOS activity plays a direct role in the pathogenesis of insulin resistance
  • the important role of Ikkb in the development of obesity and inflammation-induced insulin resistance.
  • It is probable that local concentrations of inflammatory mediators, such as FFAs, Tnf or other cytokines/adipokines contribute to this polarity switch
  • Tnf and other cytokines/chemokines are symptomatic of inflammation, and while they propagate and/or maintain the inflammatory state, they are not the initial cause(s) of inflammation
  • Tlr4, in particular, is stimulated by lipopolysaccharide (LPS), an endotoxin released by gram-negative bacteria
  • Tlr4 belongs to the family of Toll-like receptors that function as pattern recognition receptors that guard against microorganismal infections as part of the innate immune system.
  • Tlr4 stimulation results in the activation of both Ikkb/NFκB and JNK/AP-1 signaling, culminating in the expression and secretion of pro-inflammatory cytokines/chemokines, including, Il1b, IL-6, Tnf, Mcp1, etc. (reviewed in [57
  • Nathan Goodyear on 10 Jan 12
     
    Great review of all the known components in the inflammation, insulin resistance link
Nathan Goodyear

Toll-Like Receptor-4 Mediates Vascular Inflammation and Insulin Resistance in Diet-Indu... - 0 views

circres.ahajournals.org/...1589.short

inflammation insulin resistance obesity FFA saturated fat TLR4 NF-kappaB IKK-Beta

shared by Nathan Goodyear on 21 Dec 11 - No Cached
  • Nathan Goodyear on 21 Dec 11
     
    high saturated fat intake (excess FFA) shown to contribute to obesity through TLR4 receptors.  TLR4 receptors are mediators in the innate immunity.   The result will be both IKK-Beta and NF-KappaB.
Nathan Goodyear

Histochemistry and Cell Biology, Volume 127, Number 2 - SpringerLink - 0 views

www.springerlink.com/...yj35n4j531j67211

TLR TLR-4 toll-like receptors inflammtion obesity LPS lipopolysaccharides

shared by Nathan Goodyear on 19 Jan 12 - No Cached
  • Nathan Goodyear on 19 Jan 12
     
    Abstract only, but this study shows that the innate immunity plays a role in the development of obesity through the TLR.  LPS was shown to stimulate the inflammatory cascade through the TLRs
Nathan Goodyear

TLR Signaling in the Gut in Health and Disease - 0 views

www.jimmunol.org/...4453.full

TLR toll-like receptors gut inflammation disease health

shared by Nathan Goodyear on 08 Mar 12 - No Cached
  • Nathan Goodyear on 08 Mar 12
     
    How the gut contributes to inflammation and disease: through TLR.
Nathan Goodyear

The intestinal epithelial barrier: how to dist... [Semin Immunol. 2007] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...17324587

TLR toll-like receptors NODs GI gut immunity inflammation microbiota bacteria dysbiosis

shared by Nathan Goodyear on 08 Mar 12 - No Cached
  • Nathan Goodyear on 08 Mar 12
     
    TLRs and NODs play important role in GI mucosal immunity.
Nathan Goodyear

BACTERIAL INTERACTIONS WITH CELLS OF THE INTESTINAL MUCOSA: TOLL-LIKE RECEPTORS AND NOD... - 0 views

gut.bmj.com/...1182.long

gut bacteria microbiota dysbiosis health GI TLRs NODs

shared by Nathan Goodyear on 08 Mar 12 - No Cached
  • Nathan Goodyear on 08 Mar 12
     
    How interactions between the bacteria, both commensal and pathogenic, occur.  This can precipitate disease or promote health.  This occurs through TLRs and Nods
Nathan Goodyear

Benign prostatic hyperplasia: a new meta... [J Endocrinol Invest. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24458832

BPH benign prostatic hypertrophy Toll-like receptors TLRs hormone hormones low Testosterone T estrogen estradiol aromatase prostate metabolism

shared by Nathan Goodyear on 20 Feb 14 - No Cached
  • Nathan Goodyear on 20 Feb 14
     
    The authors of this paper describe BPH as a metabolic disease: involving inflammation with increased expression of TLRs, hormone imbalance and altered metabolism
Nathan Goodyear

High expression of Toll-like receptor 4/myeloid differentiation factor 88 signals corre... - 0 views

www.ncbi.nlm.nih.gov/...PMC2833250

colon cancer colorectal cancer cancer LPS lipopolysaccharides

shared by Nathan Goodyear on 11 Sep 17 - No Cached
  • Nathan Goodyear on 11 Sep 17
     
    High TLR4 and MyD88 expression on the surface of colorectal cancer cells associated with increase liver mets potential and worsened prognosis.  LPS works through TLR4 and MyD88.
Nathan Goodyear

Lipopolysaccharide-induced toll-like receptor 4 signaling enhances the migratory abilit... - 0 views

www.sciencedirect.com/...S0039606013001050

LPS lipopolysaccharides cancer

shared by Nathan Goodyear on 11 Sep 17 - No Cached
  • Nathan Goodyear on 11 Sep 17
     
    LPS stimulation induced increased mets potential in esophageal cell culture study.
Nathan Goodyear

The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic... - 0 views

www.ncbi.nlm.nih.gov/...PMC3962576

microglia LDN low dose naltrexone pain inflammation

shared by Nathan Goodyear on 05 Jul 17 - No Cached
  • orally active competitive opioid receptor antagonist
  • 4.5 mg, though the dosage can vary a few milligrams below or above that common value
  • At the low dosage level, naltrexone exhibits paradoxical properties, including analgesia and anti-inflammatory actions
  • ...10 more annotations...
  • LDN may be an effective treatment for FM
  • In addition to the antagonist effect on mu-opioid and other opioid receptors, naltrexone simultaneously has an antagonist effect on non-opioid receptors (Toll-like receptor 4 or TLR4) that are found on macrophages such as microglia
  • It is via the non-opioid antagonist path that LDN is thought to exert its anti-inflammatory effects
  • Once activated, microglia produce inflammatory and excitatory factors that can cause sickness behaviors such as pain sensitivity, fatigue, cognitive disruption, sleep disorders, mood disorders, and general malaise
  • The neuroprotective action appears to result when microglia activation in the brain and spinal cord is inhibited
  • By suppressing microglia activation, naloxone reduces the production of reactive oxygen species and other potentially neuroexcitatory and neurotoxic chemicals
  • suppressed TNF-alpha, IL-6, MCP-1, and other inflammatory agents in peripheral macrophages
  • individuals with greater ESR at baseline experienced a greater drop in pain when taking LDN
  • LDN has been reported to reduce not only self-reported pain in that condition but also objective markers of inflammation and disease severity
  • Naltrexone has also shown some promise in improving disease severity in multiple sclerosis
  • Nathan Goodyear on 05 Jul 17
     
    LDN maybe useful in treating chronic pain via anti-inflammatory effects on microglia.
Nathan Goodyear

The Role of Toll-Like Receptor 4 in Infectious and Noninfectious Inflammation - 0 views

www.hindawi.com/...6978936

cytokine storm TLR4 TLR-4 inflammation

shared by Nathan Goodyear on 17 Apr 20 - No Cached
  • Nathan Goodyear on 17 Apr 20
     
    To be read
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