Patterns of hemolysis, erythropoiesis, and iron distribution define unique disease trajectories in three mouse models of genetic anemia

Abstract

Hemolytic anemias involve premature red blood cell (RBC) destruction and present complex phenotypes, including disturbances in iron metabolism, extramedullary erythropoiesis, and systemic organ involvement. To guide the selection of appropriate murine models for studying pathophysiology and pharmacologic treatments of human hemolytic disorders, we systematically characterized three genetic mouse models commonly used to investigate such conditions: sickle cell disease (SCD), β-thalassemia (THAL), and hereditary spherocytosis (SPH). We sought to clarify how these models differ in the severity and nature of hemolysis, the balance between erythropoietic responses and iron regulation, and the long-term patterns of iron distribution. Our findings reveal that SPH mice exhibit severe intravascular hemolysis and suppressed hepcidin levels, leading to unopposed intestinal iron absorption and extensive tissue iron loading, especially in the liver. In contrast, SCD and THAL mice display predominantly extravascular hemolysis, moderate anemia, relatively stable hepcidin levels, and balanced erythropoiesis with partially regulated iron overload. Single-cell ribonucleic acid (RNA) sequencing of spleens highlighted distinct erythropoietic progenitor distributions, whereas iron-isotope tracing experiments confirmed divergent RBC turnover kinetics and tissue distribution. This study defines distinct disease trajectories for common hemolytic disease models by providing a unique comparative framework. Our work will support more informed model selection and refined experimental design to investigate hemolytic anemia pathobiology and therapeutics.