Biology subjects

Rodewald, H.-R.

Publications and source records attributed to Rodewald, H.-R..

9 recordsLinked to original sources

bioRxiv2026

The Onset of Myeloid Differentiation in Hematopoietic Progenitors In Vivo is Coordinated with S-phase Progression

Hematopoiesis produces diverse cell types in large quantities. How hematopoietic stem cells (HSCs) initiate lineage differentiation in vivo is not known. Here, we jointly measure chromatin accessibility and transcriptomes in single stem and progenitor cells and uncover a tight interplay between cell-cycle progression and the onset of differentiation. The cell cycle continuously accelerates as HSCs transition to uncommitted multipotent progenitors. In these uncommitted progenitors, proliferative activation is followed by the opening of myeloid-specific chromatin loci in S phase and, subsequently, myeloid gene expression. S phase-coupled onset of myeloid differentiation becomes quantitatively enhanced in emergency myelopoiesis. At the molecular level, we find that chromatin occupancy by HOXA9 - a key transcription factor of uncommitted progenitors - predicts whether the transition through S phase will initiate myelopoiesis, or whether the uncommitted progenitor state will be retained. Taken together, our findings provide a mechanistic framework for the onset of myeloid lineage differentiation in vivo.

systems biology↗

bioRxiv2026

Early postnatal Flt3+ hematopoietic progenitors realize fate-restricted and long-lived output in vivo

Hematopoietic progenitors downstream of hematopoietic stem cells (HSC) are now recognized as the main drivers of day-to-day hematopoiesis. While embryonic and adult HSC fates have been studied in detail, less information exists on stages downstream from HSC, notably in the multipotent progenitor compartment. The early postnatal period represents an important growth phase of the animal and its immune system. Developing immune lineages must be generated in large numbers rapidly, and populate expanding organ niches. To shed light on this critical period, we focused our experiments on early postnatal Flt3+ hematopoietic progenitors, and combined genetic single progenitor barcoding using Polylox with Flt3-driven, inducible fate mapping. Key immune cell types, including T and B lymphocytes (lymphocytes), innate lymphocytes (ILC) 1-3, NK cells, and granulocytes and monocytes (myeloid) emerged from Flt3+ hematopoietic progenitors. Barcode analysis revealed that about 75% of Flt3+ hematopoietic progenitors had unipotent fates for lymphocytes, or ILC or myeloid cells, while the remaining fraction showed unprecedented fate combinations for these lineages. Focusing on ILC only, we uncovered clonal fate restriction towards ILC1, or ILC2, or ILC3 in tissues. These data indicate early tissue seeding by progenitors, and further differentiation towards discrete subsets in situ. In addition to these fate analyses, induction of fluorescent marker at this intermediate stage of hematopoiesis showed that Flt3+ progenitors generated a wave of progeny lasting for over one year. The washout of these cells over time provided kinetic data of cell turnover in major immune cell compartments (in the circulation and in tissues) in vivo. In conclusion, we tracked the fate of large numbers (in the order of hundreds) of Flt3+ progenitor clones in situ. These intermediate progenitors downstream of HSC displayed mostly lineage-restricted fates as well as strong fate complexity, thus serving as a source for early tissue seeding and durable immune lineage.

developmental biology↗

bioRxiv2025

Clonal Dynamics in the Male Germline from Development to Next Generation

Germ cells secure the continuity and evolutionary potential of species. Yet how reproductive success is allocated among the founder cells of the mammalian male germline, the primordial germ cells (PGCs), remains unknown. Here, we quantitatively traced individual PGCs, non-invasively barcoded in mouse embryos, across their establishment, lifelong maintenance within the testis, spermatogenesis, and transmission to the next generation. We found that highly skewed clonal contributions arise from a very early stochastic bottleneck during migration to the developing testes and remain stable throughout adult reproductive life. Reproductive success during adulthood was proportional to the embryonically established PGC clone size. Mathematical modeling shows that the patchy compartmentalization of PGC clones within the extended thin seminiferous tubules maintain clonal diversity and safeguard against the expansion of clones that gain a selective advantage. These findings uncover fundamental principles governing the development, stability, and evolutionary transmission of the mammalian germline.

developmental biology↗

bioRxiv2025

Susceptibility of Kit-mutant mice to sepsis caused by enteral dysbiosis, not mast cell deficiency

Kit-mutant mice are highly susceptible to polymicrobial sepsis elicited by cecal ligation and puncture (CLP). This vulnerability has been attributed to the mast cell deficiency of Kit mutants, suggesting key roles of mast cells in antibacterial defense. We show that mice lacking mast cells but wild-type for Kit are as resistant to sepsis as mast cell-proficient mice, excluding mast cells as protective factor. Induction of sepsis by direct injection of intestinal microbiota instead of surgical gut perforation revealed comparable protective responses of Kit-deficient and Kit wild-type mice, indicating intact antibacterial immunity in the absence of Kit. Notably, cecal contents of Kit-mutant mice contained 1000-fold greater Escherichia coli colony-forming units compared to wild-type mice. Consistently, 16S rRNA gene sequencing revealed a broad compositional shift characterized by enrichment of Enterobacteriaceae and other taxa associated with inflammatory intestinal states, in keeping with intestinal dysmotility in Kit-mutant mice. Thus, upon intestinal puncture, overrepresentation of pathogenic bacteria led to a more severe infection of Kit mutants compared to wild-type controls. Hence, the susceptibility of Kit-mutant mice to sepsis is caused by enteral dysbiosis, not mast cell deficiency. These findings highlight the importance of considering genotype-dependent effects on endogenous microbiota composition in CLP models. Collectively, our results show that immunological resistance to sepsis is independent of mast cells.

immunology↗

bioRxiv2024

Holistic genetic barcoding reveals a lineage tree of tissue macrophage development

Tissue macrophages are crucial for organ development and homeostasis, yet the developmental routes leading to tissue macrophages remain controversial. By combining unbiased Polylox barcoding with computational inference, we comprehensively mapped tissue macrophage ontogeny in mice from gastrulation to adult organs. Our data reveal a lineage tree of all tissue macrophages. This tree originates from a pan-hematopoietic progenitor at embryonic day (E)6.5 and branches, via oligolineage progenitors (E7.5-E9.5), into organ-specific macrophage lineages by E10.5. Barcode analysis in embryonic tissues and adult organ fragments suggests that local macrophage colonies, formed by organ-specific progenitors, persist into adulthood. Indeed, spatial fate mapping with Polytope barcoding detects local Kupffer cell colonies of the size predicted by the lineage tree model. Our findings uncover the origin of tissue-resident macrophages from a lineage tree, and show how holistic barcoding can comprehensively map complex cellular lineage specification. One-Sentence SummaryHolistic, time- and space-resolved barcoding in the embryo reveals a unified lineage tree for all tissue macrophages, generating local macrophage colonies persisting in adult organs.

developmental biology↗

bioRxiv2024

Polytope: High-resolution epitope barcoding for in vivo spatial fate-mapping

Tracing the fate of individual cells and their progeny remains a challenging task. While imaging-based fate-mapping provides spatial information, it generally lacks complexity due to limited label diversity, resulting in diminished capture of comprehensive lineages and fate maps. Here, we introduce Polytope, an epitope barcoding system capable of generating up to 512 unique color codes. Comprising nine epitope tag cassettes flanked by loxP sites, Polytope allows random excision via Cre recombinase, creating unique color codes detectable through multiplexed imaging. Using an engineered Polytope mouse, we traced the fate of hundreds of clones across tissues in vivo, from embryonic development until adulthood. Together, Polytope enables high-resolution imaging-based fate-mapping through endogenous epitope barcoding, comprehensively capturing the spatial organization of complex clonal dynamics in situ. One-Sentence SummaryPolytope is an imaging-based barcoding system to trace lineages at clonal and spatial resolution in living organisms using a diverse set of color-coded markers.

developmental biology↗

bioRxiv2021

Loss of Usp22 enhances histone H2B monoubiquitination and stimulates intracellular and systemic interferon immunity

Interferons protect from virus infections by inducing hundreds of interferon-stimulated genes (ISG) which orchestrate anti-viral adaptive and innate immunity. Upon viral infection or type I interferon (IFN) stimulation of cell lines, a histone modification, monoubiquitinated histone 2B (H2Bub1), increases at ISG loci, raising the possibility that a specific chromatin state can broadly stimulate IFN immunity in vivo. Here we show that, in the absence of virus infection or elevated interferon levels, mice lacking the relevant deubiquitinase, Usp22, in immune cells have elevated H2Bub1 levels. Hypermonoubiquitinated H2B is physically associated with dozens of ISG loci, and expression of large numbers of ISG is upregulated. This epigenetic state promotes intracellular and systemic immune phenotypes akin to adaptive and innate interferon immunity, and thereby identifies Usp22 as a negative regulator of interferon immunity.

immunology↗

bioRxiv2020

Hematopoietic stem cells self-renew symmetrically or gradually proceed to differentiation

It is not known whether hematopoietic stem cells (HSCs) undergo symmetric or asymmetric cell divisions in the unperturbed bone marrow. Here, we integrate data from HSC fate mapping and cell-cycle-dependent labeling through mathematical inference and thus gain insight into how HSCs coordinate self-renewal with differentiation. We find that most HSC divisions in adult mice are symmetric self-renewing, replacing HSCs lost by direct differentiation and death, and slowly expanding the HSC population. This expansion maintains constant HSC output to multipotent progenitors (MPPs), despite declining HSC differentiation rate with age. We identify a linear hierarchy of differentiation states between tip HSCs and MPPs, where Tie2-driven HSC fate mapping fully covers the progression of the differentiating cells. A turning point from self-renewal to accelerated cell differentiation occurs between early-stage and late-stage MPPs, just before lineage differentiation becomes manifest in single-cell transcriptomes. This stem cell hierarchy precedes lineage differentiation and may limit mutation accumulation in the hematopoietic system.

systems biology↗

bioRxiv2020

Resolving fate and transcriptome of hematopoietic stem cell clones

Adult bone marrow harbors a mosaic of hematopoietic stem cell (HSC) clones of embryonic origin, and recent work suggests that such clones may have coherent lineage fates. To probe under physiological conditions whether HSC clones with different fates are transcriptionally distinct, we developed PolyloxExpress - a Cre recombinase-dependent DNA substrate for in situ barcoding that allows parallel readout of barcodes and transcriptomes in single cells. We describe differentiation-inactive, multilineage and lineage-restricted HSC clones, find that they reside in distinct regions of the transcriptional landscape of hematopoiesis, and identify corresponding gene signatures. All clone types contain proliferating HSCs, indicating that differentiation-inactive HSCs can undergo symmetric self-renewal. Our work establishes an approach for studying determinants of stem cell fate in vivo and provides molecular evidence for fate coherence of HSC clones.

immunology↗