This suggests that SGK1 may take part in the inhibition of activation and inflammation at the basal level. of SGK1 in microglia induced its toxic conversion, in which it took amoeboid morphology characteristic of reactive microglia, increased CD68 expression, quickened its proliferation, and showed higher susceptibility to ATP and subsequent cell death. Our data indicate that SGK1 plays pivotal roles in inhibiting its pathological activation, and suggest its potential function as a therapeutic target for the treatment of various disorders related to the inflammation in the CNS. cells did not display the corresponding band (Figure 1B). We also examined SGK3 at the protein level and it was not affected by knockout of the gene (Figure 1C). Open in a separate window Figure 1 The gene is ablated by means of the CRISPR/Cas9 system. (A) The CRISPR/Cas9 system was applied to BV-2 cells, and mutations in exon 4 were obtained (see Materials and methods). The wild-type sequence is shown with a target site (underlined) of gRNA. A protospacer adjacent motif (PAM) is shown with white letters in a black box in the wild-type sequence. Expected cleavage site is indicated by arrowhead. Non-identical nucleotides are shown with gray letters. The border between exon 4 and the following intron is shown by a vertical dashed line. Dashes in the sequences represent deleted nucleotides. Those cells underwent immunoblotting using anti-SGK1 (B) and anti-SGK3 (C) antibodies. Protein loading was monitored with actin. Changes in morphology and CD68 expression in SGK1-/- cells We first assessed the effect of SGK1 on morphology of microglial cells because inflammation affects its configuration [1,18-20]. Up to 24 h after plating the cells, the majority of cells showed a ramified shape with long process(es) (Figure 2A). However, most of the cells exhibited a relatively round shape, which is characteristic of activated microglia (cells; 44.4 4.7%, n = 9, vs cells 65.5 3.9%, n = 9, P 0.01, Figure 2A). Open in a separate window Figure 2 Disruption of the gene leads to activated features in BV-2 cells. A. Representative images of cells 24 h after being plated are shown. Scale bar; 100 m. Bar chart indicates the proportion of round amoeboid-like cells. n = 9. **P 0.01 vs cells, Students t-test. B. Cells were either untreated or treated with LPS (500 ng/ml) for 24 h, and then fixed. CD68 protein was visualized by immunofluorescence staining using an antibody for CD68 conjugated with FITC (green). For nuclear staining, the cells were stained with DAPI (blue). Representative images from three independent experiments were shown. Scale bar; 50 m. C. Cells were incubated with LPS (500 ng/ml) for 4 h. After RNA extraction and reverse transcription to synthesize cDNA, quantitative real-time PCR was performed to monitor iNOS expression. n = 5-8. *P 0.05 vs cells, Students t-test. We also inspected the expression levels of CD68, an activation marker of microglial cells [21,22]. Immunofluorescence analysis showed that cells were positive for CD68 while cells were relatively less labelled (Figure 2B). When cells were treated with LPS, CD68 signals were elevated in both cells and ML204 cells provided more intensive signals than cells did. These results ML204 suggest that disruption of SGK1 encourages microglial activation (Figure 2B). Igf1 The effect of SGK1 disruption on iNOS gene expression induced by LPS To test whether loss of SGK1 affects inflammatory response, LPS-induced iNOS gene expression was determined. Basal levels of iNOS mRNA were not different between and (cells; 1.0 0.9 fold, n = 8, vs cells; 0.9 0.5 fold, n = 5, P 0.05, Figure 2C). Interestingly, LPS augmented iNOS expression to a greater extent in cells than in cells (cells; 90.9 22.6 fold, n = 8, vs cells; 196.0 23.7 fold, n = 5, compared with untreated cells, P 0.05, Figure 2C). This pattern is consistent with our previous study that an SGK inhibitor promoted LPS-induced iNOS expression [8]. The effect of SGK1 disruption on proliferation We then evaluated whether growth is influenced by ablation of the gene. After the cells were seeded on plates, the fields were randomly selected and the corresponding fields ML204 were sequentially examined every 24 h. As shown in Figure 3A and ?and3B,3B, cells grew faster than cells, and the growth rate of the SGK1+/- cells was.