Extensive epigenetic reprogramming involves in memory CD8+ T-cell differentiation. The elaborate epigenetic rewiring underlying the heterogeneous functional states of CD8+ T cells remains hidden. Here, we profile single-cell chromatin accessibility and map enhancer-promoter interactomes to characterize the differentiation trajectory of memory CD8+ T cells. We reveal that under distinct epigenetic regulations, the early activated CD8+ T cells divergently originated for short-lived effector and memory precursor effector cells. We also uncover a defined epigenetic rewiring leading to the conversion from effector memory to central memory cells during memory formation. Additionally, we illustrate chromatin regulatory mechanisms underlying long-lasting versus transient transcription regulation during memory differentiation. Finally, we confirm the essential roles of Sox4 and Nrf2 in developing memory precursor effector and effector memory cells, respectively, and validate cell state-specific enhancers in regulating Il7r using CRISPR-Cas9. Our data pave the way for understanding the mechanism underlying epigenetic memory formation in CD8+ T-cell differentiation.
CD8-Positive T-Lymphocytes/metabolism* ; Cell Differentiation ; Chromatin/immunology* ; Animals ; Mice ; Immunologic Memory ; Epigenesis, Genetic ; SOXC Transcription Factors/immunology* ; NF-E2-Related Factor 2/immunology* ; Mice, Inbred C57BL ; Gene Regulatory Networks ; Enhancer Elements, Genetic

OBJECTIVE To establish and apply a method for simultaneous determination of the contents of dicentrine， protopine and coptisine in Tibetan Corydalis pallida of different origins， and to provide reference for origin determination and quality control of the kind of medicinal materials. METHODS Ultra performance liquid chromatography-tandem quadrupole mass spectrometry method was used. The determination was performed on Agilent EC-C18 column （100 mm×2.1 mm， 2.7 μm） with mobile phase consisted of acetonitrile-0.1% formic acid by gradient elution. The flow rate was 0.2 mL/min， and the column temperature was set at 35 ℃ . MS detection was carried out by electrospray ionization in positive modes， multiple reaction monitoring mode was used for quantitative analysis. RESULTS The injection mass concentrations of dicentrine， protopine， coptisine ranged from 5.88 to 117.60， 53.70 to 1 074.00， and 4.85 to 97.00 ng/mL， respectively， showing a good linear relationship with their respective peak areas （r＝0.998 2， 0.991 9， and 0.999 6， respectively）. The limits of quantitation were 2.35， 1.07 and 1.46 ng/mL； the limits of detection were 1.17， 0.54， 0.49 ng/mL， respectively. RSDs of precision， stability （24 h） and repeatability tests were all lower than 2.0％. The average recovery rates were 97.41%， 98.89% and 105.44%（ all RSDs＜5.0％， n＝6）. CONCLUSIONS The established method has good selectivity and high accuracy， and is suitable for the rapid analysis of dicentrine， protopine and coptisine in Corydalis. The total contents of three alkaloids in different original medicinal materials are from high to low in order of C. chrysosphaera， C. mucronifera， C. pygmaea， C. hendersonii and C. conspersa. The alkaloid contents in C. chrysosphaera and C. mucronifera are relatively similar， but no dicentrine has been detected in C. conspersa and C. hendersonii.