bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.04.04.645037

The bone marrow niche and hematopoietic system are distinctly remodeled by CD45-targeted astatine-211 radioimmunotherapy

Hagen, M. W.·Setiawan, N. J.·Dexter, S. L.·Woodruff, K. A.·Gaerlan, F. K.·Orozco, J. J.·Termini, C. M.
View original source ↗Export metadata ↓

Abstract

Radioimmunotherapy (RIT) is used to treat patients with hematological malignancies known to infiltrate the bone marrow (BM) microenvironment. RIT uses target-specific monoclonal antibodies stably conjugated to radionuclides to deliver cytotoxic radiation to cells of interest. While RIT is effective at delivering radiation to cancer cells, normal tissue is also exposed to radiation upon RIT, the consequences of which are largely unknown. Here, we studied the cellular and molecular effects of CD45-targeted astatine-211 (211At) RIT, IgG non-targeted 211At RIT, and Cesium-137 total-body irradiation (TBI) on hematopoietic cells and their BM niche in wild-type immunocompetent mice. Relative to non-targeted RIT or TBI, CD45-targeted RIT significantly delayed hematopoietic regeneration overall in the peripheral blood and BM and reduced hematopoietic stem/progenitor cell recovery and colony-forming ability. While BM endothelial cells (ECs) do not express the CD45 antigen, CD45-targeted RIT significantly depleted BM ECs compared to non-targeted RIT or TBI. RNA sequence analysis revealed significantly different transcriptomic profiles of BM ECs from CD45-RIT-treated mice compared to non- targeted RIT or TBI. ECs from CD45-RIT-treated mice, but not TBI or IgG-RIT-treated mice, were transcriptionally enriched for TGF{beta}, NOTCH, and IFN signaling pathways compared to untreated mice. Collectively, our study indicates that CD45-targeted RIT severely impacts hematopoietic and EC niche recovery compared to non- targeted approaches. Future studies are required to determine the long-term consequences of such RIT-driven effects on BM niche physiology and how BM niche reprogramming by RIT affects cancer cells. KEY POINTSO_LICD45-targeted radioimmunotherapy more effectively suppresses the hematopoietic system than non- targeted radiation delivery. C_LIO_LIThe bone marrow vascular niche is differentially reprogrammed by CD45-targeted radioimmunotherapy compared to non-targeted radiation delivery. C_LI

Source connections

Explore related subjects

cell biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hagen, M. W., Setiawan, N. J., Dexter, S. L., Woodruff, K. A., Gaerlan, F. K., Orozco, J. J., Termini, C. M.. 2025-04-05. The bone marrow niche and hematopoietic system are distinctly remodeled by CD45-targeted astatine-211 radioimmunotherapy. https://doi.org/10.1101/2025.04.04.645037

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Differential requirement for the Ire1 luminal domain in Candida albicans drug susceptibility and pathogenicity

The opportunistic human pathogen Candida albicans depends on the unfolded protein response (UPR) for cell wall integrity, antifungal tolerance, filamentous growth, and virulence. The UPR is driven by the conserved transmembrane sensor Ire1, which is activated either by misfolded proteins through its luminal domain or by lipid bilayer stress (LBS) through its transmembrane domain. In budding yeast, these two activation modes deploy divergent transcriptional programs. Whether the requirement for these two input domains is separable in C. albicans, where the cell membrane and cell wall are themselves the targets of major antifungal drug classes, remains unknown. Here, we engineered a C. albicans strain expressing Ire1 lacking an intact luminal domain (ire1{Delta}LD), which no longer detects proteotoxic stress. The ire1{Delta}LD strain grew in the presence of the azole antifungals fluconazole and miconazole but was highly sensitive to heat shock, cell wall stress, and the echinocandin caspofungin. It was also unable to sustain filamentous growth and showed reduced virulence in a Caenorhabditis elegans infection model. RNA sequencing revealed only modest changes to the steady-state transcriptome of ire1{Delta}LD cells. Together, these findings define a differential requirement for the input domains of C. albicans Ire1, uncoupling growth under azole-induced membrane stress from the cell wall, thermal, and virulence-associated outputs that depend on proteotoxic sensing, a distinction that could inform antifungal strategies targeting the UPR.

cell biology↗
bioRxiv2026

Nucleosome Core Allostery Governs Chromatin Recognition and Cell Fate

Nucleosomes regulate chromatin folding, accessibility, and factor recruitment. Current models primarily attribute these functions to histone tail modifications, while the core is largely viewed as a structural scaffold. Yet subtle changes within the nucleosome core can produce profound functional consequences, and the mechanisms underlying these effects remain unclear. Here, we describe nucleosome core allostery as a fundamental principle of chromatin regulation that amplifies the impact of minimal nucleosome variations. Leveraging natural differences between H2A.Z variants, we show that the nucleosome core encodes distinct conformational dynamics that propagate allosterically, thereby controlling nucleosome accessibility and recognition by chromatin factors. As a result, a single buried amino acid substitution alone is sufficient to reprogram nucleosome dynamics and bias cell identity. Our findings establish the nucleosome core as an allosteric regulatory module and provide a generalizable framework for how subtle variation within nucleosomes is amplified into diverse biological outcomes in development and disease.

cell biology↗
bioRxiv2026

YAP/TAZ-controlled ERK dynamics coordinate progenitor expansion and differentiation commitment

Progenitor cells must proliferate to expand the cell population, yet terminal differentiation requires this proliferative state to end. How signaling controls the duration of this proliferative window remains poorly understood. Using adipogenesis and live single-cell imaging of differentiation, cell-cycle, and ERK-activity reporters, we show that YAP and TAZ coordinate progenitor expansion with differentiation commitment by regulating ERK dynamics. YAP/TAZ maintain cells in a fluctuating high-ERK state that promotes proliferation while actively keeping the differentiation driver PPARG below the threshold for irreversible commitment. Crucially, this differentiation block is not explained by proliferation alone: inhibiting CDK4/6 or AKT suppressed proliferation without restoring differentiation, whereas MEK-ERK inhibition restored differentiation even when YAP/TAZ activity remained high. As YAP/TAZ activity decreases, dampened ERK fluctuations trigger PPARG activation. These findings support a self-limiting model in which YAP/TAZ-driven progenitor expansion progressively increases cell density and contact-dependent Hippo signaling, reducing YAP/TAZ activity and terminating the proliferative phase. Consequently, transient YAP/TAZ activation expands the progenitor pool while preserving subsequent differentiation, whereas sustained activation suppresses commitment. Together, these findings identify YAP/TAZ-controlled ERK dynamics as the nexus coordinating progenitor expansion with terminal differentiation and suggest that slower density-dependent Hippo feedback may set the duration of this proliferative window to regulate differentiated cell-number output.

cell biology↗