Dexmedetomidine Alters the Inflammatory Profile of Rat Microglia In Vitro.

BACKGROUND: Microglia are a primary mediator of the neuroinflammatory response to neurologic injury, such as that in traumatic brain injury. Their response includes changes to their cytokine expression, metabolic profile, and immunophenotype. Dexmedetomidine (DEX) is an α2 adrenergic agonist used as a sedative in critically ill patients, such as those with traumatic brain injury. Given its pharmacologic properties, DEX may alter the phenotype of inflammatory microglia. METHODS: Primary microglia were isolated from Sprague-Dawley rats and cultured. Microglia were activated using multiple mediators: lipopolysaccharide (LPS), polyinosinic-polycytidylic acid (Poly I:C), and traumatic brain injury damage-associated molecular patterns (DAMP) from a rat that sustained a prior controlled cortical impact injury. After activation, cultures were treated with DEX. At the 24-h interval, the cell supernatant and cells were collected for the following studies: cytokine expression (tumor necrosis factor-α [TNFα], interleukin-10 [IL-10]) via enzyme-linked immunosorbent assay, 6-phosphofructokinase enzyme activity assay, and immunophenotype profiling with flow cytometry. Cytokine expression and metabolic enzyme activity data were analyzed using two-way analysis of variance. Cell surface marker expression was analyzed using FlowJo software. RESULTS: In LPS-treated cultures, DEX treatment decreased the expression of TNFα from microglia (mean difference = 121.5 ± 15.96 pg/mL; p < 0.0001). Overall, DEX-treated cultures had a lower expression of IL-10 than nontreated cultures (mean difference = 39.33 ± 14.50 pg/mL, p < 0.0001). DEX decreased IL-10 expression in LPS-stimulated microglia (mean difference = 74.93 ± 12.50 pg/mL, p = 0.0039) and Poly I:C-stimulated microglia (mean difference = 23.27 ± 6.405 pg/mL, p = 0.0221). In DAMP-stimulated microglia, DEX decreased the activity of 6-phosphofructokinase (mean difference = 18.79 ± 6.508 units/mL; p = 0.0421). The microglial immunophenotype was altered to varying degrees with different inflammatory stimuli and DEX treatment. CONCLUSIONS: DEX may alter the neuroinflammatory response of microglia. By altering the microglial profile, DEX may affect the progression of neurologic injury.

Ibrutinib Prevents Acute Lung Injury via Multi-Targeting BTK, FLT3 and EGFR in Mice.

Ibrutinib has potential therapeutic or protective effects against viral- and bacterial-induced acute lung injury (ALI), likely by modulating the Bruton tyrosine kinase (BTK) signaling pathway. However, ibrutinib has multi-target effects. Moreover, immunity and inflammation targets in ALI treatment are poorly defined. We investigated whether the BTK-, FLT3-, and EGFR-related signaling pathways mediated the protective effects of ibrutinib on ALI. The intratracheal administration of poly I:C or LPS after ibrutinib administration in mice was performed by gavage. The pathological conditions of the lungs were assessed by micro-CT and HE staining. The levels of neutrophils, lymphocytes, and related inflammatory factors in the lungs were evaluated by ELISA, flow cytometry, immunohistochemistry, and immunofluorescence. Finally, the expression of proteins associated with the BTK-, FLT3-, and EGFR-related signaling pathways were evaluated by Western blotting. Ibrutinib (10 mg/kg) protected against poly I:C-induced (5 mg/kg) and LPS-induced (5 mg/kg) lung inflammation. The wet/dry weight ratio (W/D) and total proteins in the bronchoalveolar lavage fluid (BALF) were markedly reduced after ibrutinib (10 mg/kg) treatment, relative to the poly I:C- and LPS-treated groups. The levels of ALI indicators (NFκB, IL-1ß, IL-6, TNF-α, IFN-γ, neutrophils, and lymphocytes) were significantly reduced after treatment. Accordingly, ibrutinib inhibited the poly I:C- and LPS-induced BTK-, FLT3-, and EGFR-related pathway activations. Ibrutinib inhibited poly I:C- and LPS-induced acute lung injury, and this may be due to its ability to suppress the BTK-, FLT3-, and EGFR-related signaling pathways. Therefore, ibrutinib is a potential protective agent for regulating immunity and inflammation in poly I:C- and LPS-induced ALI.

Antiviral effects of single-stranded polynucleotide inhibitors of the influenza virion-associated transcriptase against influenza virus infection of hamsters and ferrets.

Administration of a single-stranded polynucleotide copolymer containing 9% cytidine residues and 91% 4-thiouridine residues [poly(C,S4U10)], a known potent inhibitor of the virion transcriptase of influenza viruses, suppressed the amount of virus recoverable from the nasal washes of influenza virus-infected hamsters and ferrets. The incidence of sneezing and nasal discharge in infected ferrets was also reduced. In hamsters, poly(C,S4U10) was more effective than amantadine-HCl or Virazole. Polyinosinic acid in combination with poly-5-hydroxy cytidylic acid also had anti-influenza effects. Poly(C,S4U10) annealed to polyadenylic acid was not effective, nor was the double-stranded polymer (polyinosinic acid) . (polycytidylic acid) even when complexed with carboxymethylcellulose and polylysine. No toxic effects of poly(C,S4U10) were apparent in the treated hamsters and ferrets, and high doses (greater than or equal to 2.86 g/kg) administered intraperitoneally to mice produced no adverse effects.

Studies on the mode of action of single-stranded polynucleotides which are antiviral against encephalomyocarditis virus infection of mice.

Poly(dI) and poly(dC) administered separately or sequentially show no antiviral effects against EMC virus infection of mice, whereas poly(rI) and poly(rC) are antiviral in such treatment regimens without evidence of interferon induction. The antiviral effects of poly(rI) and poly(rC) appear to depend on single-strandedness because their antiviral effects are decreased by annealing to poly(dC) and poly(dI) respectively. This decrease in antiviral effect would not seem to be due to an adverse effect of polydeoxyribonucleotides on EMC virus infection because the polydeoxyribonucleotides have no effect on the antiviral activity of another single-stranded RNA, E. coli tRNA.

Anti-viral activity of single-stranded homopolynucleotides against encephalomyocarditis virus and Semliki Forest virus in adult mice without interferon induction.

Single administrations of poly C or poly I are anti-viral against infections of encephalomyocarditis (EMC) and Semliki Forest virus (SFV) in mice but poly U and poly A are not. The degree of protection is dose-dependent and mice which die do so at a later time when untreated controls even in a strain of mouse in which the time of death is not dependent on the dose of virus given. No circulating interferon is found after treating mice with poly C or poly I even at polynucleotide doses which give the same degree of protection as the interferon inducer, poly I:C. Several additional features distinguish the protection by poly C and poly I from interferon induction: the effect is low 24h before infection and maximal 6 h before infection, the effect is short-lived and mice do not show hypo-reactivation to repeated treatment. Limited treatment of mice with poly I:C, interferon or poly C before infection itself results in additional protection when poly C is also administered after infection, indicating that poly C has an effect after onset of virus replication. After infection poly C and poly I are both more effective by the intravenous route but before infection they are most effective when administered by the same route as the virus. Quantitative comparisons of the protective effects of poly C, poly I and the interferon inducer, poly I:C, are possible from dose response curves of the polynucleotides at different times relative to infection and by different routes of administration. The results are considered in relation to the presence of homopolyribonucleotide tracts in the viral genomes and effects on the reticulo-endothelial system of the mice.