| Objective To investigate the potential role of protein kinase N2 (PKN2) in lipopolysaccharides (LPS) -induced sepsisassociated cognitive dysfunction. Methods A total of 48 male C57BL/6J mice were randomly divided into three groups and received a single intraperitoneal injection of LPS at different doses (0, 1.25, or 2.5 mg/kg). Sepsis phenotypes were assessed at 6 h, 12 h, and 24 h post-LPS injection using murine sepsis score (MSS) among 30 mice. Then, 30 mice were monitored for 7-day survival rates and subsequently subjected to cognitive behavioral tests. After behavioral assessments, mice were euthanized, prefrontal cortex (PFC) and hippocampal tissues were collected for transcriptomic analysis, Western blot (WB), and immunofluorescence experiments. An additional 18 mice were sacrificed 24 h after LPS exposure. PFC and hippocampal tissues were harvested for reverse transcription-polymerase chain reaction (RT-PCR) to quantify inflammatory cytokine expression levels. Inflammatory related signaling molecules were detected by WB. Results During LPS acute exposure period (6 h, 12 h and 24 h), the MSS significantly increased in LPS-exposed mice. And the mRNA of proinflammatory cytokines TNFα and IL1β, chemokine CCL5 and anti-inflammatory factor IL10 in the prefrontal cortex (PFC) and hippocampus increased in a dose-dependent manner. After seven days of LPS exposure, behavioral experiments showed that cognitive index was reduced in the high-dose LPS exposure group. After seven days of LPS exposure, immunofluorescence showed that the number of microglia marker Iba1 positive cells in the PFC and hippocampus of mice significantly increased in the LPS exposure group. Transcriptome analysis showed that the mRNA of three inflammation related signalng molecules, ATM, Cul3 and PKN2 were significantly up-regulated in the PFC and hippocampus of mice in the LPS exposure group. WB verified that the protein levels of ATM and PKN2 in the PFC of mice significantly increased in the high-dose LPS exposure group. The protein level of Cul3 in hippocampus increased in both LPS exposure groups, and the protein level of PKN2 increased in low-dose LPS exposure group. PKN2 mRNA and protein were also upregulated in the PFC and hippocampus of mice after LPS exposure for 24 h. Conclusion Protein kinase PKN2 may be an early target of sepsis-related cognitive dysfunction caused by LPS. |
