title: Knockdown of interleukin-1 receptor type-1 on endothelial cells attenuated stress-induced neuroinflammation and prevented anxiety-like behavior.
abstract: Interleukin-1β (IL-1β) is an inflammatory cytokine that plays a prominent role in stress-induced behavioral changes. In a model of repeated social defeat (RSD), elevated IL-1β expression in the brain was associated with recruitment of primed macrophages that were necessary for development of anxiety-like behavior. Moreover, microglia activation and anxiety-like behavior associated with RSD did not occur in IL-1 receptor type-1 knock-out (IL-1R1(KO)) mice. Therefore, the objective of this study was to examine the role of IL-1 signaling in RSD-induced macrophage trafficking to the brain and anxiety-like behavior. Initial studies revealed that RSD did not increase circulating myeloid cells in IL-1R1(KO) mice, resulting in limited macrophage trafficking to the brain. In addition, IL-1R1(KO) bone marrow-chimera mice showed that IL-1R1 expression was essential for macrophage trafficking into the brain. To differentiate cellular mediators of stress-induced IL-1 signaling, endothelial-specific IL-1R1 knock-down (eIL-1R1kd) mice were used. Both wild-type (WT) and eIL-1R1kd mice had increased circulating monocytes, recruitment of macrophages to the brain, and altered microglia activation after RSD. Nonetheless, RSD-induced expression of IL-1β, TNF-α, and IL-6 mRNA in brain CD11b(+) cells was attenuated in eIL-1R1kd mice compared with WT. Moreover, anxiety-like behavior did not develop in eIL-1R1kd mice. Collectively, these findings demonstrated that there was limited RSD-induced priming of myeloid cells in IL-1R1(KO) mice and disrupted propagation of neuroinflammatory signals in the brain of eIL-1R1kd mice. Furthermore, these data showed that transduction of IL-1 signaling by endothelial cells potentiates stress-induced neuroinflammation and promotes anxiety-like behavior.
authors: Oral Biology Division, Department of Neuroscience, Institute for Behavioral Medicine Research, and Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio 43210.
authors: Eric S
authors: ES
authors: Wohleb
authors: Jenna M
authors: JM
authors: Patterson
authors: Vikram
authors: V
authors: Sharma
authors: Ning
authors: N
authors: Quan
authors: Jonathan P
authors: JP
authors: Godbout
authors: John F
authors: JF
authors: Sheridan
mesh_terms: D000818:Animals; D001007:Anxiety / Q000378:metabolism*; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D042783:Endothelial Cells / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D007375:Interleukin-1 / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D060888:Real-Time Polymerase Chain Reaction; D053573:Receptors, Interleukin-1 Type I / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013315:Stress, Psychological / Q000378:metabolism*
chemical_list: C583355:IL1R1 protein, mouse; D007375:Interleukin-1; D053573:Receptors, Interleukin-1 Type I
keywords: anxiety; blood-brain barrier; interleukin-1; microglia; neuroinflammation; stress