Cigarette Smoke Extraction Enhances The Expression Of FIZZ1/RELMα In Rat Lung Epithelial L2Cells

BackgroundFound in inflammatory zone1protein or Resistin-like molecule alpha (FIZZ1/RELMα) is arecently discovered cysteine-rich secretory protein. It is reported to be associated withpulmonary inflammation and airway remodeling. Our early study has shown that FIZZ1/RELMαincreased in smoke induced chronic obstructive pulmonary disease (COPD). However, the directrole of FIZZ1/RELMα stimulated by cigarette smoke extraction (CSE) produced in pulmonaryepithelium has not been determined. We examined the expression and function ofFIZZ1/RELMα in rat epithelial L2cells，in order to find the relationship between FIZZ1/RELMαand COPD.Methods(1) The rat lung epithelial L2cells (CCL-149) were stimulated by CSE, the expression ofFIZZ1/RELMα mRNA was detected by RT-PCR. FIZZ1/RELMα protein level was detected bywestern blot and confocal immunofluorescence assay.(2) CCL-149cells were treated by different concentrations and different time ofrecombinant protein FIZZ1/RELMα．After treatment, the expression level of leukocyte-8(IL-8)was detected by ELISA.Results(1) The results showed that without the stimulation of5%CSE, the expression ofFIZZ1/RELMα mRNA and protein level in CCL-149cells was very low. When5%CSEstimulated CCL-149cells, FIZZ1/RELMα mRNA level expressed significantly higher thancontrol groups (P <0.05). Western blot showed that5%CSE enhanced the protein expression ofFIZZ1/RELMα in a time-dependent manner (correlation coefficient r=0.92, P <0.01). Confocalimmunofluorescence assay indicated that there was weak green fluorescence in the cytoplasm in PBS control group. After incubated with5%CSE for24h, green fluorescence was obvious incytoplasm. FIZZ1/RELMα stimulated with CSE was mainly increased in the cytoplasm.(2) Recombinant protein FIZZ1/RELMα promoted the expression of IL-8in adose-dependent and time-dependent manner (r=0.904and0.777, P <0.01).Conclusion(1) The current study demonstrates that CSE significantly enhances the expression ofFIZZ1/RELMα mRNA and protein in CCL-149cells.(2) Recombinant protein FIZZ1induces the expression of IL-8and may thus participate inthe process of COPD airway inflammation and airflow obstruction.