1. Academic Validation
  2. Protein Kinase C Theta Inhibition Attenuates Lipopolysaccharide-Induced Acute Lung Injury through Notch Signaling Pathway via Suppressing Th17 Cell Response in Mice

Protein Kinase C Theta Inhibition Attenuates Lipopolysaccharide-Induced Acute Lung Injury through Notch Signaling Pathway via Suppressing Th17 Cell Response in Mice

  • Inflammation. 2019 Dec;42(6):1980-1989. doi: 10.1007/s10753-019-01058-2.
Mengqin Li 1 Yan Zhao 1 Jing He 1 Wang Deng 1 Li Cheng 2 Zhi Jiang 3 Daoxin Wang 4
Affiliations

Affiliations

  • 1 Department of Respiratory and critical care medicine, The Second Affiliated Hospital of Chongqing Medical University, 76 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
  • 2 Physical Examination Center, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
  • 3 Department of Emergency, The Affiliated Hospital of North Sichuan Medical College, Chongqing, China.
  • 4 Department of Respiratory and critical care medicine, The Second Affiliated Hospital of Chongqing Medical University, 76 Linjiang Road, Yuzhong District, Chongqing, 400010, China. wangdaoxin11@163.com.
Abstract

Acute lung injury (ALI)/acute respiratory distress syndrome is characterized by increased pulmonary inflammation, where T helper 17 (Th17) cells play an important regulatory role. Notch signaling critically regulates Th17 differentiation and is known to be linked with proximal T cell by protein kinase C theta (PKCθ). We hypothesized that PKCθ inhibition could attenuate ALI by suppressing Th17 response via the Notch signaling pathway. Male C57BL/6 mice were treated with phosphate-buffered saline (PBS), lipopolysaccharide (LPS), LPS and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT, a Notch signaling inhibitor), or LPS and PKCθ Inhibitor (PI), and the bronchoalveolar lavage fluid (BALF), blood, and lung tissues were harvested at 48 h after the LPS challenge. CD4+ T cells were treated with DAPT or PI and harvested after 72 h. PKCθ inhibition markedly attenuated pathological changes and decreased the wet to dry weight ratio of the mouse lungs. The total cell and neutrophil counts, tumor necrosis factor-α (TNF- α) in BALF, myeloperoxidase activity in lung tissue, and the leukocyte count in whole blood were markedly reduced by PKCθ inhibition. The concentration of interleukin (IL)-17 and IL-22 in BALF, and the percentage of CD4+IL-17A+ T cells in the lungs were significantly downregulated by PKCθ inhibition. A similar trend was observed for the expression of retinoic acid-related orphan receptor gamma t and IL-23 Receptor after PKCθ inhibition accompanied with inactivation of the Notch signaling pathway in vivo and in vitro. Collectively, these data demonstrated that PKCθ inhibition protects against LPS-induced ALI by suppressing the differentiation and pathogenicity of Th17, at least partially, through a Notch-dependent mechanism.

Keywords

Acute lung injury; IL-23R; Notch; PKCθ; RORγt; Th17.

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