Our previous studies demonstrated that the micro
integral membrane protein (
MIMP) located within the
integral membrane protein of Lactobacillus plantarum CGMCC 1258 protected the intestinal barrier from injury. To further analyze the protective effects conferred to intestinal epithelial cells by
MIMP, we established transient
MIMP-expressing NCM460 cells (NCM460/
MIMP) as a means of assessing their susceptibility to
infection. We constructed a recombinant eukaryotic expression vector using pcDNA3.1(-) and the
MIMP gene. The recombinant vector was then transduced into NCM460 cells and the anti-infective properties of the transient
MIMP-expressing NCM460/
MIMP cells assessed. Flow cytometric analysis revealed that 82.16% ±12.22% of NCM460/
MIMP cells expressed
MIMP and Western blot analysis confirmed high levels of
MIMP expression. Attachment assays showed that the ability of enteropathogenic Escherichia coli (EPEC) to attach to NCM460/
MIMP cells decreased significantly compared to adhesion observed to NCM460 cells. Western blot and quantitative RT-PCR showed that the expression levels of tight junction (TJ)
proteins, including
claudin-1,
occludin, JAM-1 and ZO-1 in NCM460/
MIMP cells infected with EPEC were similar to levels observed in uninfected NCM460 cells. Fluorescence further showed that NCM460/
MIMP cells had significantly higher TJ
protein staining intensity ocompared to NCM460 cells and transmission electron microscopy indicated that TJ structure was unchanged in NCM460/
MIMP cells infected with EPEC compared to NCM460 cells after EPEC
infection. Expression levels of PKC-η and phosphorylated
occludin were also higher after EPEC
infection in NCM460/
MIMP cells compared to expression levels in EPEC-infected NCM460 cells. These data demonstrated that NCM460/
MIMP cells possessed EPEC anti-infective properties related to the activation of
protein kinase C-η and
occludin phosphorylation.