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Systemic interleukin-6 inhibition ameliorates acute neuropsychiatric phenotypes in a murine model of acute lung injury.

ABSTRACT: Acute neuropsychiatric impairments occur in over 70% of patients with acute lung injury. Mechanical ventilation is a well-known precipitant of acute lung injury and is strongly associated with the development of acute delirium and anxiety phenotypes. In prior studies, we demonstrated that IL-6 mediates neuropathological changes in the frontal cortex and hippocampus of animals with mechanical ventilation-induced brain injury; however, the effect of systemic IL-6 inhibition on structural and functional acute neuropsychiatric phenotypes is not known. We hypothesized that a murine model of mechanical ventilation-induced acute lung injury (VILI) would induce neural injury to the amygdala and hippocampus, brain regions that are implicated in diverse neuropsychiatric conditions, and corresponding delirium- and anxiety-like functional impairments. Furthermore, we hypothesized that these structural and functional changes would reverse with systemic IL-6 inhibition. VILI was induced using high tidal volume (35 cc/kg) mechanical ventilation. Cleaved caspase-3 (CC3) expression was quantified as a neural injury marker and found to be significantly increased in the VILI group compared to spontaneously breathing or anesthetized and mechanically ventilated mice with 10 cc/kg tidal volume. VILI mice treated with systemic IL-6 inhibition had significantly reduced amygdalar and hippocampal CC3 expression compared to saline-treated animals and demonstrated amelioration in acute neuropsychiatric behaviors in open field, elevated plus maze, and Y-maze tests. Overall, these data provide evidence of a pathogenic role of systemic IL-6 in mediating structural and functional acute neuropsychiatric symptoms in VILI and provide preclinical justification to assess IL-6 inhibition as a potential intervention to ameliorate acute neuropsychiatric phenotypes following VILI.

SUBMITTER: Anwar F

PROVIDER: S-EPMC9469063 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Systemic interleukin-6 inhibition ameliorates acute neuropsychiatric phenotypes in a murine model of acute lung injury.

Anwar Faizan F Sparrow Nicklaus A NA Rashid Mohammad Harun MH Guidry Gena G Gezalian Michael M MM Ley Eric J EJ Koronyo-Hamaoui Maya M Danovitch Itai I Ely E Wesley EW Karumanchi S Ananth SA Lahiri Shouri S

Critical care (London, England) 20220913 1

Acute neuropsychiatric impairments occur in over 70% of patients with acute lung injury. Mechanical ventilation is a well-known precipitant of acute lung injury and is strongly associated with the development of acute delirium and anxiety phenotypes. In prior studies, we demonstrated that IL-6 mediates neuropathological changes in the frontal cortex and hippocampus of animals with mechanical ventilation-induced brain injury; however, the effect of systemic IL-6 inhibition on structural and funct ...[more]

PMID: 36100846

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Project description:Rationale: Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical syndrome with a mortality rate of up to 40%, and it is characterized by a prominent inflammatory cascade. The inflammasome and pyroptosis play crucial regulatory roles in regulating various inflammatory-related diseases by serving as pivotal signaling platforms for inflammatory responses and mediating the release of substantial quantities of inflammatory factors. Our previous studies confirmed that GC-1, a clinical-stage thyroid hormone analog, effectively mitigated pulmonary fibrosis by restoring mitochondrial function in epithelial cells. However, the potential effects of GC-1 on macrophage inflammasome assembly and pyroptosis in lung injury as well as the underlying mechanisms, remain unclear. Methods: The effects of GC-1 on lung injury, oxidative damage and inflammation were evaluated in two murine models of ALI (LPS- or HCl-induced models) by assessing lung pathology, the concentrations of IL-1β and IL-18 in BAL fluid, inflammasome and the levels of inflammasome- and pyroptosis-related proteins. Additionally, the impact of GC-1 on ROS-mediated inflammasome assembly and pyroptosis was investigated by examining ROS levels, Nrf2 signaling, and inflammasome adaptor protein ASC levels in mouse alveolar macrophages and human THP-1 macrophages treated with LPS and ATP. The Nrf2 inhibitor ML385 and the mitochondrial-ROS inhibitor Mito-TEMPO were used to further elucidate the effect of GC-1 on the Nrf2-p53-ASC pathway. Results: GC-1 significantly alleviated inflammation and lung injury in ALI model mice, as indicated by pulmonary pathology, inflammatory cytokine levels, ROS production and pyroptosis rates. Consistently, GC-1 inhibited ASC recruitment and oligomerization in macrophages, which suppressed the gasdermin D-mediated release of IL-1β and IL-18. These findings indicated a reduction in inflammasome assembly and pyroptosis initiation. Further research revealed that GC-1 may mitigate oxidative stress induced by mitochondrial damage through Nrf2 signaling, thereby inhibiting the expression of ROS-activated p53 and the target gene ASC. This protective effect of GC-1 could be reversed by ML385 and mimicked by Mito-TEMPO. Conclusions: This study presents a novel mechanism for treating ALI in which GC-1 inhibits macrophage ROS-mediated inflammasome assembly and pyroptosis through Nrf2-p53-ASC pathway. These findings highlight the promising potential of the use of GC-1 as an anti-inflammatory and antioxidant drug in the treatment of ALI/ARDS.

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Dataset Information

Systemic interleukin-6 inhibition ameliorates acute neuropsychiatric phenotypes in a murine model of acute lung injury.

Publications

Systemic interleukin-6 inhibition ameliorates acute neuropsychiatric phenotypes in a murine model of acute lung injury.

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