Biology subjects

Zuniga-Pflucker, J. C.

Publications and source records attributed to Zuniga-Pflucker, J. C..

4 recordsLinked to original sources

bioRxiv2025

Uncovering the Heterogeneity and Ontogeny of Mouse Thymic Macrophages Reveals an Unexpected Early Checkpoint Role

Thymic macrophages (TMs) maintain tissue homeostasis by clearing the large numbers of apoptotic cells generated during T cell development, but how TM heterogeneity relates to their developmental origin and role in thymocyte maturation remains incompletely understood. Using complementary flow-cytometric, single-cell transcriptomic, and genetic approaches, we resolved two major TM populations corresponding to TIMD4+ cortical and CX3CR1+ medullary/cortico-medullary macrophages. TIMD4+ VCAM1+ TMs displayed a prominent efferocytosis and apoptotic-cell-clearance program, whereas TIMD4- VCAM1+ TMs were enriched for antigen-presentation and interferon-response pathways. Fate mapping revealed unequal progenitor contributions to these populations, and CCR2 deficiency selectively reduced TIMD4- VCAM1+ TMs and thymic monocytes, supporting ongoing input from circulating precursors. Exploratory pseudotime analysis further identified a transcriptional continuum from Ly6c2+ Ccr2+ monocytes toward macrophage states. Using MaFIA fetal thymic organ cultures, AP20187-mediated depletion of Csf1r-expressing myeloid cells reduced CD4+CD8+ thymocyte differentiation and produced a coordinated accumulation of DN3 cells, loss of DN4 cells, and reduction in CD27 expression. These convergent changes identify the DN3-to-DN4 transition as a developmental stage that requires an intact Csf1r-expressing myeloid compartment, and establish a functional connection between the thymic myeloid niche and early {beta} T cell development. Together, our study refines the phenotypic and developmental organization of mouse TMs and reveals a previously under-appreciated requirement for myeloid-cell support during progression through the {beta}-selection checkpoint.

immunology↗

bioRxiv2025

Interlinked roles for HEB and Id3 in fetal gamma-delta T cell commitment and functional programming

T cells expressing the {gamma}{delta} T cell receptor (TCR) develop in a stepwise process initiating at the {beta}/{gamma}{delta} T cell branchpoint followed by maturation and acquisition of effector functions, including the ability to produce interleukin-17 (IL-17) as {gamma}{delta}T17 cells. Previous studies linked TCR signal strength and fate choices to the transcriptional regulator HEB (Tcf12) and its antagonist, Id3, but how these factors regulate different stages of {gamma}{delta} T cell development has not been determined. We found that immature fetal {gamma}{delta}TCR+ cells from conditional Tcf12 knockout (HEB cKO) mice were defective in activating the {gamma}{delta}T17 program at an early stage, whereas Id3 deficient (Id3-KO) mice displayed a partial block in {gamma}{delta}T17 maturation and a defect in IL-17 production. We also found that HEB cKO mice failed to upregulate Id3 during {gamma}{delta}T17 development, whereas HEB overexpression elevated the levels of Id3 in collaboration with TCR signaling. Moreover, Egr2 and HEB were bound to several of the same regulatory sites on the Id3 gene locus in the context of early T cell development. Therefore, our findings reveal an interlinked sequence of events during which HEB and TCR signaling synergize to upregulate Id3, which enables maturation and acquisition of the {gamma}{delta}T17 effector program. One Sentence SummaryThe transcription factor HEB synergizes with TCR signaling to upregulate Id3, which is required for the maturation of fetal IL-17-producing {gamma}{delta} T cells.

immunology↗

bioRxiv2024

E protein control of NKgammadeltaT cell development through both generation and function of the stereotypic Vgamma1Vdelta6.3 TCR

T cell receptor (TCR) signals regulate important developmental transitions through induction of the E protein antagonist, Id3; however, Id3-deficiency produces paradoxical effects on {gamma}{delta} T cell subsets. Here, we show here that Id3-deficiency attenuates the development of V{gamma}3-expressing {gamma}{delta} T cells, while markedly enhancing the development of V{gamma}1V{delta}6.3-expressing NK{gamma}{delta}T cells. Id3-deficiency does so by regulating both the generation of the stereotypic V{gamma}1V{delta}6.3 TCR expressed by NK{gamma}{delta}T cells and its capacity to support development. Indeed, we determined that the Trav15 segment, which encodes the V{delta}6.3 TCR subunit, is directly bound by E proteins that control its expression. Moreover, once expressed, the resulting V{gamma}1V{delta}6.3 TCR in capable of specifying the innate-like NK{gamma}{delta}T cell fate in a cell-autonomous and developmentally-unrestricted manner that is restrained by the Id3/E axis. Together, these data indicate that the paradoxical behavior of NK{gamma}{delta}T cells in the Id3-deficient setting is entirely determined by its stereotypic V{gamma}1V{delta}6.3 TCR complex.

immunology↗

bioRxiv2019

NOTCH1 signaling establishes the medullary thymic epithelial cell progenitor pool during mouse fetal development

The cortical and medullary thymic epithelial cell (cTEC and mTEC) lineages are essential for inducing T cell lineage commitment, T cell positive selection and the establishment of self-tolerance, but the mechanisms controlling their fetal specification and differentiation are poorly understood. Here, we show that Notch signaling is required to specify and expand the mTEC lineage. Notch1 is expressed by and active in TEC progenitors. Deletion of Notch1 in TECs resulted in depletion of mTEC progenitors and dramatic reductions in mTECs during fetal stages, consistent with defects in mTEC specification and progenitor expansion. Conversely, forced Notch signaling in all TEC resulted in widespread expression of mTEC progenitor markers and profound defects in TEC differentiation. In addition, lineage-tracing analysis indicated that all mTECs have a history of receiving a Notch signal, consistent with Notch signaling occurring in mTEC progenitors. Interestingly, this lineage analysis also showed that cTECs are divided between Notch lineage-positive and lineage-negative populations, identifying a previously unknown complexity in the cTEC lineage.

developmental biology↗