Acute lung injury (ALI) is a severe clinical disease marked by dysregulated inflammation response and has a high rate of morbidity and mortality. Macrophages, which play diverse roles in the inflammatory response, are becoming therapeutic targets in ALI. In this study we investigated the effects of dehydrocostus lactone (DHL), a natural sesquiterpene, on macrophage activation and LPS-induced ALI. The macrophage cell line RAW264.7 and primary lung macrophages were incubated with DHL (0, 3, 5, 10 and 30 μmol/L) for 0.5 h and then challenged with LPS (100 ng/mL) for up to 8 hours. C57BL/6 mice were intratracheally injected with LPS (5 mg/kg) to induce acute lung injury (ALI) and then treated with a range of DHL doses intraperitoneally (5 to 20 mg/kg). The results showed that DHL inhibited LPS-induced production of proinflammatory mediators such as iNOS, NO, and cytokines including TNF-α, IL-6, IL-1β, and IL-12 p35 by suppressing the activity of NF-κB via p38 MAPK/MK2 and Akt signaling pathway in macrophages. The in vivo results revealed that DHL significantly attenuated LPS-induced pathological injury and reduced cytokines expression in the lung. NF-κB, p38 MAPK/MK2 and Akt signaling molecules were also involved in the anti-inflammatory effect. Collectively, our findings suggested that DHL is a promising agent for alleviating LPS-induced ALI.

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by inflammation, multifocal fibrotic lesions and excessive collagen deposition with limited therapies. As a major bioactive compound in garlic, S-allyl-l-cysteine (SAC) is a neuroprotective drug candidate to prevent cognitive decline, however, its anti-pulmonary fibrotic activity remains unknown. Here, we investigated whether SAC could attenuate bleomycin (BLM)-induced pulmonary fibrosis and inflammation in mice. Our results showed that SAC dose-dependently reduced the infiltration of inflammatory cells, pulmonary lesions and collagen deposition in BLM treated mice with downregulated mRNA expression levels of fibrotic genes including alpha smooth muscle actin (α-SMA), fibronectin, collagen I and collagen III as well as the protein level of α-SMA. In addition, SAC could also reduce the mRNA expression of inflammatory mediators such as TNF-α and iNOS. Furthermore, higher phosphorylation of AKT and NF-κB p65 in IPF patient samples and murine samples was verified by immunohistochemistry while SAC could decrease the phosphorylation level of AKT and NF-κB p65 in mice stimulated with BLM. These findings, for the first time, indicate that SAC might mediate AKT/NF-κB signaling pathway to inhibit BLM-induced pulmonary fibrosis and support the potential role of SAC as an anti-pulmonary fibrosis agent.

Idiopathic pulmonary fibrosis (IPF) is a progressive and highly lethal inflammatory interstitial lung disease characterized by aberrant extracellular matrix deposition. Macrophage activation by cytokines released from repetitively injured alveolar epithelial cells regulates the inflammatory response, tissue remodeling, and fibrosis throughout various phases of IPF. Our previous studies demonstrate that nuclear factor of activated T cells cytoplasmic member 3 (NFATc3) regulates a wide array of macrophage genes during acute lung injury pathogenesis. However, the role of NFATc3 in IPF pathophysiology has not been previously reported. In the current study, we demonstrate that expression of NFATc3 is elevated in lung tissues and pulmonary macrophages in mice subjected to bleomycin (BLM)-induced pulmonary fibrosis and IPF patients. Remarkably, NFATc3 deficiency (NFATc3^+/-) was protective in bleomycin (BLM)-induced lung injury and fibrosis. Adoptive transfer of NFATc3^+/+ macrophages to NFATc3^+/- mice restored susceptibility to BLM-induced pulmonary fibrosis. Furthermore, in vitro treatment with IL-33 or conditioned medium from BLM-treated epithelial cells increased production of CCL2 and CXCL2 in macrophages from NFATc3^+/+ but not NFATc3^+/- mice. CXCL2 promoter-pGL3 Luciferase reporter vector showed accentuated reporter activity when co-transfected with the NFATc3 expression vector. More importantly, exogenous administration of recombinant CXCL2 into NFATc3^+/- mice increased fibrotic markers and exacerbated IPF phenotype in BLM treated mice. Collectively, our data demonstrate, for the first time, that NFATc3 regulates pulmonary fibrosis by regulating CCL2 and CXCL2 gene expression in macrophages.

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal lung disease with a limited therapeutic strategy. Mitochondrial oxidative stress in macrophages is directly linked to IPF. Elamipretide(SS-31) is a mitochondrion-targeted peptide that has been shown to be safe and beneficial for multiple diseases. However, whether SS-31 alleviates IPF is unclear. In the present study, we used a bleomycin (BLM)-induced mouse model followed by SS-31 injection every other day to investigate its role in IPF and explore the possible mechanism. Our results showed that SS-31 treatment significantly suppressed BLM-induced pulmonary fibrosis and inflammation, with improved histological change, and decreased extracellular matrix deposition and inflammatory cytokines release. Impressively, the expression percentage of IL-1β and IL-18 was downregulated to lower than half with SS-31 treatment. Mechanistically, SS-31 inhibited IL-33- or lipopolysaccharide(LPS)/IL-4-induced production of IL-1β and IL-18 in macrophages by suppressing NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome activation. Nuclear factor erythroid 2-related factor 2(Nrf2) was dramatically upregulated along with improved mitochondrial function after SS-31 treatment in activated macrophages and BLM-induced mice. Conversely, there was no significant change after SS-31 treatment in Nrf2−/− mice and macrophages. These findings indicated that SS-31 protected against pulmonary fibrosis and inflammation by inhibiting the Nrf2-mediated NLRP3 inflammasome in macrophages. Our data provide initial evidence for the therapeutic efficacy of SS-31 in IPF.

Postoperative cognitive dysfunction (POCD), an important postoperative neurological complication, is very common and has an elevated incidence in elderly patients. Sevoflurane, an inhaled anesthetic, has been demonstrated to be associated with POCD in both clinical and animal studies. However, how to prevent POCD remains unclear. Minocycline, a commonly used antibiotic can cross the blood-brain barrier and exert an inhibitory effect on inflammation in the central nervous system. The present work aimed to examine the protective effect and mechanism of minocycline on sevoflurane-induced POCD in aged mice. We found that 3% sevoflurane administered 2 h a day for 3 consecutive days led to cognitive impairment in aged animals. Further investigation revealed that sevoflurane impaired synapse plasticity by causing apoptosis and neuroinflammation and thus induced cognitive dysfunction. However, minocycline pretreatment (50 mg/kg, i.p, 1 h prior to sevoflurane exposure) significantly attenuated learning and memory impairments associated with sevoflurane in aged animals by suppressing apoptosis and neuroinflammation. Moreover, a mechanistic analysis showed that minocycline suppressed sevoflurane-triggered neuroinflammation by inhibiting Notch signaling. Similar results were also obtained in vitro. Collectively, these findings suggested minocycline may be an effective drug for the prevention of sevoflurane-induced POCD in elderly patients.