Transgenic Mouse Models for Dendritic Spine Imaging

Thy1-YFP-H mice (stock 003782)^{57 (link)}, which express yellow fluorescent protein (YFP) in L5 pyramidal neurons, Rosa26-stop-DTR mice (stock 007900)^{58 (link)}, which express a conditional DTR-encoding allele in the ROSA locus, Rag1^−/− mice (stock 002216)^{59 (link)}, Tnf^−/− mice (stock 005540)^{60 (link)}, Il6^−/− mice (stock 002650) and B6 CD45.1 mice (stock 002014) were purchased from the Jackson Laboratory. Cx3cr1^CreER mice^{35 (link)} were obtained from the laboratory of Wen-Biao Gan (New York University). Cx3cr1^GFP mice^{34 (link)} were obtained from the laboratory of Dan Littman (New York University). To image dendritic spine plasticity in Cx3cr1^CreER/+;R26^iDTR/+ and Tnf^−/− mice, these mice were crossed to Thy1-YFP-H mice. For systemic immune challenge, mice were administered poly(I:C) (Sigma P1530; by i.p. injection) that was dissolved in DPBS. Mice were group-housed in temperature-controlled rooms on a 12-h light–dark cycle and were randomly assigned to different treatment groups. The group size was determined based on previous studies using the same methodologies^{28 (link),29 (link),30 (link),31 (link),32 (link)}. Both male and female mice were used. All mice were maintained at the NYU Skirball Institute specific-pathogen-free animal facility and handled in accordance with the institutional guidelines for animal care and use.