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    Abstract:
    SUMMARY SARS-CoV-2 has been found capable of inducing prolonged pathologies collectively referred to as Long-COVID. To better understand this biology, we compared the short- and long-term systemic responses in the golden hamster following either SARS-CoV-2 or influenza A virus (IAV) infection. While SARS-CoV-2 exceeded IAV in its capacity to cause injury to the lung and kidney, the most significant changes were observed in the olfactory bulb (OB) and olfactory epithelium (OE) where inflammation was visible beyond one month post SARS-CoV-2 infection. Despite a lack of detectable virus, OB/OE demonstrated microglial and T cell activation, proinflammatory cytokine production, and interferon responses that correlated with behavioral changes. These findings could be corroborated through sequencing of individuals who recovered from COVID-19, as sustained inflammation in OB/OE tissue remained evident months beyond disease resolution. These data highlight a molecular mechanism for persistent COVID-19 symptomology and characterize a small animal model to develop future therapeutics.
    Keywords:
    Proinflammatory cytokine
    Proinflammatory cytokines traditionally thought to be derived exclusively from the immune system and were therefore considered to be primarily responsible for initiating inflammatory in the myocardium. The effects of Proinflammatory Cytokines in the heart were discussed.
    Proinflammatory cytokine
    Citations (0)
    The influenza A virus protein PB1-F2 has been linked to the pathogenesis of both primary viral and secondary bacterial infections. H3N2 viruses have historically expressed full-length PB1-F2 proteins with either proinflammatory (e.g., from influenza A/Hong Kong/1/1968 virus) or noninflammatory (e.g., from influenza A/Wuhan/359/1995 virus) properties. Using synthetic peptides derived from the active C-terminal portion of the PB1-F2 protein from those two viruses, we mapped the proinflammatory domain to amino acid residues L62, R75, R79, and L82 and then determined the role of that domain in H3N2 influenza virus pathogenicity. PB1-F2-derived peptides containing that proinflammatory motif caused significant morbidity, mortality, and pulmonary inflammation in mice, manifesting as increased acute lung injury and the presence of proinflammatory cytokines and inflammatory cells in the lungs compared to peptides lacking this motif, and better supported bacterial infection with Streptococcus pneumoniae. Infections of mice with an otherwise isogenic virus engineered to contain this proinflammatory sequence in PB1-F2 demonstrated increased morbidity resulting from primary viral infections and enhanced development of secondary bacterial pneumonia. The presence of the PB1-F2 noninflammatory (P62, H75, Q79, and S82) sequence in the wild-type virus mediated an antibacterial effect. These data suggest that loss of the inflammatory PB1-F2 phenotype that supports bacterial superinfection during adaptation of H3N2 viruses to humans, coupled with acquisition of antibacterial activity, contributes to the relatively diminished frequency of severe infections seen with seasonal H3N2 influenza viruses in recent decades compared to their first 2 decades of circulation.
    Proinflammatory cytokine
    Citations (77)
    Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF) and interleukin-1beta (IL-1) have been found to be elevated in bronchoalveolar lavage (BAL) fluid and in plasma from patients with acute respiratory distress syndrome (ARDS). In order to measure the balance of proinflammatory cytokines and their inhibitors, we quantified the upregulation of intercellular adhesion molecules (ICAM-1) induced by ARDS BAL fluids in human alveolar type II-like (A459) cells, and defined proinflammatory activity as the amount of ICAM-1 induced by the SAL fluids. Proinflammatory activity was detected in 77% of the SAL fluids sampled during the first week of ARDS, was found maximal during the 3 first days after onset of ARDS, and was significantly greater than in BAL specimens from at risk patients. Blocking experiments with specific inhibitors of TNF and IL-1 added to the BAL fluids indicated that the bioactivity measured was mainly due to IL-1. In contrast, proinflammatory activity of conditioned supernates from endotoxin-treated alveolar macrophages was mostly due to TNF. Using a bioassay that measures balance of cytokines with their inhibitors, our results indicate that the net proinflammatory activity in ARDS BAL fluids is attributable to IL-1 and not to TNF.
    Proinflammatory cytokine
    Citations (325)
    Abstract Objectives The study was to explore the influence of microRNA (miR)-345-3p on proinflammatory cytokines in patients with rheumatoid arthritis (RA). Methods A total of 32 RA patients and 32 healthy patients were enrolled. Proinflammatory factors in patients’ serum were detected by ELISA, and miR-345-3p was detected by RT-qPCR. The correlation between miR-345-3p expression and proinflammatory factors in RA patients was analyzed. The diagnostic value of miR-345-3p and proinflammatory factors in RA patients was analyzed by receiver operating curve diagnosis. The predictive value of miR-345-3p levels and proinflammatory factors in RA patients was analyzed by multivariate Cox regression. HFLS-RA and HFLS cells were cultured, in which miR-345-3p and proinflammatory cytokines were detected by RT-qPCR. Cell proliferation and apoptosis were determined by CCK-8 and flow cytometry, respectively. Results MiR-345-3p was lowly expressed in the serum of RA patients. MiR-345-3p and proinflammatory factors were of diagnostic and predictive values in RA. Elevated miR-345-3p restrained the production of proinflammatory factors of HFLS-RA cells, improved cell proliferation, and reduced apoptosis. Conclusion MiR-345-3p is a potential biomarker and ameliorates RA by reducing the release of proinflammatory cytokines.
    Proinflammatory cytokine
    The brain's response to ischemic injury is an acute and long-term inflammatory process. This process involves activation of resident cells (mainly microglia, hematogenous macrophages), production of proinflammatory mediators and infiltration of various proinflammatory cells (mainly neutrophils and lymphocytes). These cells play an essential role in ischemic brain tissue by releasing either proinflammatory or anti-inflammatory mediators at different time points. However, the exact pathogenesis of proinflammatory or anti-inflammatory genes in this process has not yet been elucidated. This review aims to investigate the inflammatory process of stroke, especially the role of proinflammatory and anti-inflammatory genes in the pathogenesis of stroke. We also summarize the current clinical trials of drugs that target the inflammatory mechanism for intervention.
    Proinflammatory cytokine
    Pathogenesis
    The olfactory bulb is a highly plastic structure the volume of which partly reflects the degree of afferent neural activity. In this study, 22 patients with post-infectious olfactory deficit, nine participants with post-traumatic olfactory deficit, and 17 healthy controls underwent magnetic resonance volumetry of the olfactory bulb. Patients presented with significantly smaller olfactory bulb volumes than controls; significant correlations between olfactory function and bulb volume were observed. Patients with parosmia exhibited smaller olfactory bulb volumes than those without parosmia. Findings indicate that smell deficits leading to a reduced sensory input to the olfactory bulb result in structural changes at the level of the bulb. Reduced olfactory bulb volumes may also be considered to be characteristic of parosmia.
    Bulb
    Proinflammatory reaction by the body occurs acutely in response to injury that is considered primarily beneficial. However, sustained proinflammatory cytokines observed with chronic pathologies such as metabolic syndrome, cancer, and arthritis are detrimental and in many cases is a major cardiovascular risk factor. Proinflammatory cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor α (TNFα) have long been implicated in cardiovascular risk and considered to be a major underlying cause for heart failure (HF). The failure of the anti-TNFα therapy for HF indicates our elusive understanding on the dichotomous role of proinflammatory cytokines on acutely beneficial effects versus long-term deleterious effects. Despite these well-described observations, less is known about the mechanistic underpinnings of proinflammatory cytokines especially TNFα in pathogenesis of HF. Increasing evidence suggests the existence of an active cross-talk between the TNFα receptor signaling and G-protein-coupled receptors such as β-adrenergic receptor (βAR). Given that βARs are the key regulators of cardiac function, the review will discuss the current state of understanding on the role of proinflammatory cytokine TNFα in regulating βAR function.
    Proinflammatory cytokine
    Pathogenesis