Tuning MPL signaling to influence hematopoietic stem cell differentiation and inhibit essential thrombocythemia progenitors

TY - JOUR

T1 - Tuning MPL signaling to influence hematopoietic stem cell differentiation and inhibit essential thrombocythemia progenitors

AU - Cui, Lu

AU - Moraga, Ignacio

AU - Lerbs, Tristan

AU - Van Neste, Camille

AU - Wilmes, Stephan

AU - Tsutsumi, Naotaka

AU - Trotman-Grant, Aaron Claudius

AU - Gakovic, Milica

AU - Andrews, Sarah

AU - Gotlib, Jason

AU - Darmanis, Spyros

AU - Enge, Martin

AU - Quake, Stephen

AU - Hitchcock, Ian S

AU - Piehler, Jacob

AU - Garcia, K Christopher

AU - Wernig, Gerlinde

N1 - © 2021 the Author(s)

PY - 2021/1/12

Y1 - 2021/1/12

N2 - Thrombopoietin (TPO) and the TPO-receptor (TPO-R, or c-MPL) are essential for hematopoietic stem cell (HSC) maintenance and megakaryocyte differentiation. Agents that can modulate TPO-R signaling are highly desirable for both basic research and clinical utility. We developed a series of surrogate protein ligands for TPO-R, in the form of diabodies (DBs), that homodimerize TPO-R on the cell surface in geometries that are dictated by the DB receptor binding epitope, in effect "tuning" downstream signaling responses. These surrogate ligands exhibit diverse pharmacological properties, inducing graded signaling outputs, from full to partial TPO agonism, thus decoupling the dual functions of TPO/TPO-R. Using single-cell RNA sequencing and HSC self-renewal assays we find that partial agonistic diabodies preserved the stem-like properties of cultured HSCs, but also blocked oncogenic colony formation in essential thrombocythemia (ET) through inverse agonism. Our data suggest that dampening downstream TPO signaling is a powerful approach not only for HSC preservation in culture, but also for inhibiting oncogenic signaling through the TPO-R.

AB - Thrombopoietin (TPO) and the TPO-receptor (TPO-R, or c-MPL) are essential for hematopoietic stem cell (HSC) maintenance and megakaryocyte differentiation. Agents that can modulate TPO-R signaling are highly desirable for both basic research and clinical utility. We developed a series of surrogate protein ligands for TPO-R, in the form of diabodies (DBs), that homodimerize TPO-R on the cell surface in geometries that are dictated by the DB receptor binding epitope, in effect "tuning" downstream signaling responses. These surrogate ligands exhibit diverse pharmacological properties, inducing graded signaling outputs, from full to partial TPO agonism, thus decoupling the dual functions of TPO/TPO-R. Using single-cell RNA sequencing and HSC self-renewal assays we find that partial agonistic diabodies preserved the stem-like properties of cultured HSCs, but also blocked oncogenic colony formation in essential thrombocythemia (ET) through inverse agonism. Our data suggest that dampening downstream TPO signaling is a powerful approach not only for HSC preservation in culture, but also for inhibiting oncogenic signaling through the TPO-R.

KW - Cell Differentiation/physiology

KW - Cell Membrane/metabolism

KW - Epitopes/immunology

KW - Hematopoiesis/drug effects

KW - Hematopoietic Stem Cells/metabolism

KW - Humans

KW - Ligands

KW - Megakaryocytes/metabolism

KW - Neoplasm Proteins/metabolism

KW - Proto-Oncogene Proteins/metabolism

KW - Receptors, Cytokine/metabolism

KW - Receptors, Thrombopoietin/immunology

KW - Signal Transduction/physiology

KW - Thrombocythemia, Essential/metabolism

KW - Thrombopoietin/metabolism

U2 - 10.1073/pnas.2017849118

DO - 10.1073/pnas.2017849118

M3 - Article

C2 - 33384332

SN - 0027-8424

VL - 118

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 2

M1 - e2017849118

ER -