Effect of surfactant protein A on lipopolysaccharide-induced tumor necrosis factor-α expression in human proximal tubular epithelial cells.

Abstract

BACKGROUND:

Surfactant protein A (SP-A) contributes to the regulation of sepsis-induced acute lung injury. In a previous study, we demonstrated the expression and localization of SP-A in the kidneys. The present study evaluated the effect of SP-A on lipopolysaccharide (LPS)-induced tumor necrosis factor-a (TNF-α) expression and its underlying mechanisms in the human renal tubular epithelial (HK-2) cells.

METHODS:

Indirect immunofluorescence assay was used to detect SP-A distribution and expression in HK-2 cells. HK-2 cells were treated with various concentrations of LPS (0, 0.1, 1, 2, 5, and 10 mg/L) for 8 hours and with 5 mg/L LPS for different times (0, 2, 4, 8, 16, and 24 hours) to determine the effects of LPS on SP-A and TNF-α expression. Then, HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB (NF-κB) P65 and TNF-α expression of HK-2 cells after LPS-treatment.

RESULTS:

Indirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells. Interestingly, SP-A1/SP-A2 and TNF-a expression were found to be significantly increased in HK-2 cells upon LPS treatment. Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.

CONCLUSION:

SP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.

• Authors: Jiao Liu, Zhiyong Liu, Lizhi Feng, Guohua Ding, Dechang Chen, Qingshan Zhou
• Journal: Chinese medical journal (Chin Med J (Engl)) Vol. 127 Issue 2 Pg. 343-7 ( 2014) ISSN: 2542-5641 [Electronic] China
• PMID: 24438626 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Lipopolysaccharides
• Pulmonary Surfactant-Associated Protein A
• SFTPA1 protein, human
• Tumor Necrosis Factor-alpha

Topics

• Cell Line
• Epithelial Cells (cytology, drug effects, metabolism)
• Fluorescent Antibody Technique, Indirect
• Humans
• Kidney Tubules, Proximal (cytology)
• Lipopolysaccharides (pharmacology)
• Pulmonary Surfactant-Associated Protein A (metabolism, pharmacology)
• Tumor Necrosis Factor-alpha (metabolism)