Biology subjects

Freud, A.

Publications and source records attributed to Freud, A..

3 recordsLinked to original sources

bioRxiv2026

CD200R1 Marks a Branchpoint During Human Natural Killer Cell Development in Tonsils

Human natural killer (NK) cells arise from common innate lymphoid cell (ILC) progenitor and precursor populations that are selectively enriched within secondary lymphoid tissues (SLTs) and that complete their terminal differentiation through stages of progressively lineage-restricted downstream developmental intermediates. We identify two subsets of tonsil CD94/NKG2A+NKp80- (stage 4A) NK-cell development intermediates that show differential expression of the inhibitory receptor, CD200R1. Ex vivo single-cell transcriptomic, DNA methylation, phenotypic, and functional analyses demonstrate that CD200R1 stage 4A cells represent an immature, oligopotent precursor population enriched for tissue-resident and cytokine-responsive programs. In contrast, CD200R1- stage 4A cells show more restricted NK-cell developmental potential concomitant with features of mature NK cells. These findings help to refine the human NK cell developmental pathway in tonsils and highlight CD200R1 as a useful marker delineating an uncommitted developmental state linking microenvironmental cues to NK-cell maturation and plasticity.

immunology↗

bioRxiv2026

Mapping human natural killer cell development in tonsil

Secondary lymphoid tissue, including tonsil, supports human NK cell development, but the spatial organization and tissue niches that drive this differentiation remain undefined. Here, we used single cell analysis of cyclic immunofluorescence to generate a comprehensive atlas of human NK cell development in tonsil. By integrating regional localization, chemokine signaling, cytokine availability, and cell phenotype, we show that NK cell differentiation follows a reproducible spatial trajectory defined by stage-specific cell-cell interactions. CD34+ NK cell progenitors are found in the interfollicular domain in proximity to high endothelial venules, consistent with this route of progenitor entry into tissue. Mature NK cells are primarily found in the T cell-rich parafollicular domain, where they interact with other NK cells and T cell subsets. Local inflammation increases NK cell frequency in tissue through both proliferation of NK progenitors and increased frequency of mature NK cells. Finally, we identify a subset of tonsil stromal cells that support differentiation of NK cells in vitro and proliferation of NK precursors in situ. Together, these findings demonstrate that spatial localization defines human NK cell development and provide an in situ definition of niches that support human NK cell differentiation in tonsil.

immunology↗

bioRxiv2022

Evidence for the digital programming of cellular differentiation: characterization of binary switches in lineage-determining transcription factors

Previous studies of the murine Ly49 and human KIR gene clusters have revealed a role for bidirectional promoters in the control of variegated gene expression. Whether or not competing promoters control other instances of cell fate determination remains an outstanding question. Although divergent transcripts within 300 bp are found in ~6% of human genes, an analysis of human transcription factor (TF) genes (1640) revealed that 33% possess stable divergent transcripts with a transcription start site (TSS) less than 300 bp upstream, with many separated by less than 30 bp, indicating an enrichment for potential binary switches in TFs. We have performed a detailed examination of putative bidirectional promoter switches in three lineage-determining TF genes: AHR, GATA3, and ROR{gamma}T. These genes also contain additional pairs of opposing promoters that would prevent simultaneous transcription of sense and antisense, and thus may represent simple on/off switches rather than probabilistic switches. In situ RNA hybridization of human tissues revealed mutually exclusive expression of sense versus antisense transcription, indicating switching between stable sense or antisense transcriptional states. Single-cell RNAseq confirmed the separate sense/antisense states, and revealed the identity of cells with active switch elements. Differential gene expression analysis of cells with antisense switch transcripts revealed an enrichment for genes found in immature/stem cells and a lack of genes associated with terminally differentiated cells. Taken together, these data indicate that there is a digital component to the differentiation program mediated by binary promoter switches in lineage-determining transcription factors.

developmental biology↗