Chemokine CXCL13 acts via CXCR5-ERK signaling in hippocampus to induce perioperative neurocognitive disorders in surgically treated mice
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Background: Perioperative neurocognitive disorders (PNDs) occur frequently after surgery and worsen patient outcome. How C-X-C motif chemokine (CXCL) 13 and its sole receptor CXCR5 contribute to PNDs remains poorly understood.
Methods: A PND model was created in adult male C57BL/6J and CXCR5-/- mice by exploratory laparotomy. Mice were pretreated via intracerebroventricular injection with recombinant CXCL13, short hairpin RNA against CXCL13 or a scrambled control RNA, or ERK inhibitor PD98059. Then surgery was performed to induce PNDs, and animals were assessed in the Barnes maze trial followed by a fear-conditioning test. Expression of CXCL13, CXCR5, and ERK in hippocampus was examined using Western blot, quantitative PCR, and immunohistochemistry. Levels of interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in hippocampus were assessed by Western blot.
Results: Surgery impaired learning and memory, and it increased expression of CXCL13 and CXCR5 in the hippocampus. CXCL13 knockdown partially reversed the effects of surgery on CXCR5 and cognitive dysfunction. CXCR5 knockout led to similar cognitive outcomes as CXCL13 knockdown, and it repressed surgery-induced activation of ERK and production of IL-1β and TNF-α in hippocampus. Recombinant CXCL13 induced cognitive deficits and increased the expression of phospho-ERK as well as IL-1β and TNF-α in hippocampus of wild-type mice, but not CXCR5-/- mice. PD98059 partially blocked CXCL13-induced cognitive dysfunction as well as production of IL-1β and TNF-α.
Conclusions: CXCL13-induced activation of CXCR5 may contribute to PNDs by triggering ERK-mediated production of pro-inflammatory cytokines in hippocampus.
Keywords: CXCL13; CXCR5; Hippocampus; Perioperative neurocognitive disorders; p-ERK.