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Biomedical subjects

Yana Li

Publications and source records attributed to Yana Li.

2 recordsLinked to original sources

Rbp-Jκ controls NK cell late maturation and migration via chromatin landscape remodeling.

The transcriptional regulator Rbp-Jκ is a pivotal molecular switch in Notch signaling; however, its cell-intrinsic role in natural killer (NK) cell maturation and migration remains incompletely understood. Here, we demonstrate that NK cell-specific deletion of Rbp-Jκ (Ncr1iCre × Rbp-Jκfl/fl, Rbp-JκΔNK) impairs NK cell terminal maturation and migration, as evidenced by increased retention of NK cells in bone marrow, a reduced number of circulating NK cells and decreased expression of migration mediators (CD62L, S1pr5, and Cx3cr1). Despite exhibiting an activated phenotype, Rbp-Jκ-deficient NK cells fail to control B16F10 lung metastases in vivo because of impaired tissue mobilization. Multiomics (scRNA-seq/scATAC-seq, bulk ATAC-seq, and CUT&Tag) reveal that Rbp-Jκ orchestrates chromatin remodeling in NK cells, suppressing the expression of genes related to NK cell activation and cytotoxicity while promoting the expression of genes involved in ribosome and oxidative phosphorylation. Notably, Rbp-Jκ directly binds to the Kruppel-like factor 2 (Klf2) promoter, and loss of Rbp-Jκ reduces both the mRNA and protein levels of Klf2. Klf2 overexpression rescues the decreased expression of CD62L and CX3CR1 in Rbp-Jκ-deficient NK cells. The cooccupancy of Rbp-Jκ and Klf2 at shared genomic loci is confirmed by ChIP-qPCR. In summary, our study reveals that Rbp-Jκ acts as a master regulator of NK cell terminal maturation and tissue homing via chromatin reprogramming, with Klf2 acting as its critical downstream transcription factor.

Animals

Efficacy of the NMIC-150 system in identifying extended-spectrum beta-lactamases in clinical isolates.

Extended-spectrum beta-lactamases (ESBLs) are significant contributors to the growing global crisis of antimicrobial resistance. This study evaluated the performance of the NMIC-150 System for susceptibility testing of third-generation cephalosporins (3GCs) and assessed whether ceftazidime-avibactam and aztreonam-avibactam could identify ESBL-producing carbapenem-resistant Enterobacterales (CREs). A total of 278 non-duplicate clinical isolates (Klebsiella pneumoniae, E. coli, and Proteus mirabilis) were analyzed. Antimicrobial susceptibility was determined using reference broth microdilution (BMD) and the NMIC-150 System. ESBL production was defined as an ≥eight-fold reduction in the minimum inhibitory concentration (MIC) of 3GCs in the presence of clavulanic acid, according to CLSI criteria. Whole-genome sequencing was performed to characterize ESBL and carbapenemase genes among 3GC-resistant isolates. A Random Forest model was used to predict ESBL-producing isolates based on MIC values. The NMIC-150 System demonstrated over 90% categorical and essential agreement with BMD for ceftazidime and ceftriaxone, along with robust predictive performance via Random Forest analysis. These findings suggest that the NMIC-150 System is a reliable platform for 3GC susceptibility testing and that an ≥eight-fold MIC reduction with ceftazidime-avibactam or aztreonam-avibactam may serve as a phenotypic indicator of ESBL production in CRE isolates. In conclusion, the NMIC-150 System shows potential for routine antimicrobial resistance surveillance and may facilitate the rapid identification of ESBL-producing CREs in clinical settings.

Microbial Sensitivity Tests