GSM7434355: rna_cb6f1j_kupffer_f1nsg_rep2; Mus musculus; RNA-Seq
Mice were humanely euthanized by exposure to CO2 and liver non-parenchymal cells processed for fluorescence activated cell sorting of Kupffer cells, with modifications from published methodology (Seidman et al., 2020; Sakai et al., 2019). In brief, livers were retrograde perfused for 3 min at a rate of 5-7 ml/min through the inferior vena cava with HBSS without Ca++ or Mg++ supplemented with 0.5 mM EGTA, 0.5 mM EDTA, and 20 mM HEPES. Perfusions were then switched to 40 ml of a digestion buffer, held at 37C, comprised of HBSS with Ca++ and Mg++ supplemented with 0.033 mg/ml of Liberase TM (Roche), 20 μg/ml DNaseI (Worthington), and 20 mM HEPES. Livers were then excised, minced, and digested for an additional 20 minutes in vitro at 37C with gentle rotation in 20 ml of fresh digestion buffer. The perfusion and digestion steps were performed in the presence of 1 μM flavopiridol to offset transcriptional changes associated with digestion. After tissue digestion, cells were passed through a 70-micron cell strainer and hepatocytes removed by 2 low-speed centrifugation steps at 50 X G for 2 min. Nonparenchymal cells in the supernatant were further separated from debris by pelleting for 15 min at 600 X G in 50 ml of 20% isotonic Percoll (Sigma Aldrich) at room temperature. Cells were then washed from Percoll containing buffer and suspended in 10 ml 28% OptiPrep (Sigma Aldrich) and carefully underlaid beneath 3 ml of wash buffer. The resulting gradient was centrifuged at 1,400 X G for 25 minutes at 4C with no break and cells enriched at the interface were saved and subjected to isotonic erythrocyte lysis. Enriched non-parenchymal cells were then washed, suspended in PBS, then stained for 10 minutes with Zombie NIR (BioLegend) and purified anti-CD16/32 (93, BioLegend) to label dead cells and block Fc receptors. Cells were then immunolabeled with specific antibodies of interest, washed, and sorted using a Beckman Coulter MoFlo Astrios EQ configured with spatially separated 355 nm, 405 nm, 488 nm, 561 nm, and 642 nm lasers. Hepatocytes were prepared by perfusion digestion in a retrograde fashion through the inferior vena cava to the portal vein. In brief, livers were blanched with clearing buffer, then digested with a collagenase solution at 39C. Livers were perfused for 18 minutes at 5 ml/min. The perfusion and digestion steps were performed in the presence of 1 mM flavopiridol to offset transcriptional changes associated with digestion. After digestion, individual livers were gently dissociated using forceps in Medium 199 supplemented with 5% FBS and penicillin/streptomycin/gentamycin. Crude hepatocyte preps were carefully strained through a 100-micron strainer into and isolated using a Percoll gradient. Mice were humanely euthanized by exposure to CO2 and bone marrow from femur, tibia, and iliac bones was isolated as described previously (Link et al., 2018). Bone marrow cells were seeded innon- tissue culture plates in m-CSF enriched media. After an additional 4-5 days of culture, non-adherent cells were washed off with room temperature PBS, and adherent macrophages were obtained by scraping. Performed as published previously (Gosselin et al., 2017; Oishi et al., 2016). Isolated cells were pelleted and put into 150 μl lysis/Oligo d(T) Magnetic Beads binding buffer and stored at -80°C until processing. mRNAs were enriched by incubation with Oligo d(T) Magnetic Beads (NEB, S1419S) and then fragmented/eluted by incubation at 94°C for 9 min. Poly A enriched mRNA was fragmented, in 2x Superscript III first-strand buffer with 10mM DTT (Invitrogen), by incubation at 94°C for 9 minutes, then immediately chilled on ice before the next step. The 10 μL of fragmented mRNA, 0.5 μL of Random primer (Invitrogen), 0.5 μL of Oligo dT primer (Invitrogen), 0.5 μL of SUPERase-In (Ambion), 1 μL of dNTPs (10 mM) and 1 μL of DTT (10 mM) were heated at 50°C for three minutes. At the end of incubation, 5.8 μL of water, 1 μL of DTT (100 mM), 0.1 μL Actinomycin D (2 μg/μL), 0.2 μL of 1% Tween-20 (Sigma) and 0.2 μL of Superscript III (Invitrogen) were added and incubated in a PCR machine using the following conditions: 25°C for 10 minutes, 50°C for 50 minutes, and a 4°C hold. The product was then purified with RNAClean XP beads according to manufacturer's instruction and eluted with 10 μL nuclease-free water. The RNA/cDNA double-stranded hybrid was then added to 1.5 μL of Blue Buffer (Enzymatics), 1.1 μL of dUTP mix (10 mM dATP, dCTP, dGTP and 20 mM dUTP), 0.2 μL of RNAse H (5 U/μL), 1.05 μL of water, 1 μL of DNA polymerase I (Enzymatics) and 0.15 μL of 1% Tween-20. The mixture was incubated at 16°C for 1 hour. The resulting dUTP-marked dsDNA was purified using 28 μL of Sera-Mag Speedbeads (Thermo Fisher Scientific), diluted with 20% PEG8000, 2.5M NaCl to final of 13% PEG, eluted with 40 μL EB buffer (10 mM Tris-Cl, pH 8.5) and frozen at -80°C. The purified dsDNA (40 μL) underwent end repair by blunting, A-tailing and adapter ligation as previously described (Heinz et al., 2010) using barcoded adapters (NextFlex, Bioo Scientific). Libraries were PCR-amplified for 9-14 cycles, size selected by gel extraction, quantified using a Qubit dsDNA HS Assay Kit (Thermo Fisher Scientific) and sequenced on a Hi-seq 4000 or a NextSeq 500 (Illumina, San Diego, CA) according to the manufacturer's instructions.