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bioRxiv · 10.64898/2026.06.05.729662

Hemoglobin C is prone to oxidative denaturation, resulting in red blood cell membrane damage in HbSC disease

Setayesh, T.·Tijani, A.·Kaur, H.·Khanal, S.·Zhu, Z.·Oestreicher, Z.·Sue, K.·Balla, J.·Chi, M.·Ware, R. E.·Malik, P.
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Abstract

Sickle-hemoglobin-C (HbSC) sickle cell disease is characterized by RBC dehydration (xerocytosis), which promotes polymerization of HbS. HbSC causes substantial morbidity despite lower sickling potential than HbSS, suggesting a critical detrimental role of HbC in the disease pathophysiology. We derived HbCC mice by interbreeding our HbSC mice, which demonstrated a similar RBC phenotype of xerocytosis as humans with HbCC. We compared RBCs from HbCC, HbSC, and HbSS mice. Oxidized ferryl (Fe4+)-Hb, and its oxidative-denaturation, which results in hemichrome formation (Heinz-bodies), was most pronounced in HbCC>HbSC>HbSS, despite significantly higher reactive oxygen species in HbSS, illustrating a higher propensity of HbC to denaturation than HbS. RBC deformability followed a similar pattern, with Elongation Index lowest in HbCC<HbSC<HbSS. Next, we determined if RBC from HbSC patients on hydroxyurea showed improved membrane damage. Hydroxyurea treatment reduced Heinz-body formation and improved RBC deformability, despite negligible/modest fetal hemoglobin (HbF) induction, compared to non-hydroxyurea HbSC controls. The antioxidant quercetin showed a similar reduction in Heinz-body burden and improvement in RBC deformability as hydroxyurea, without affecting Hb or HbF concentration, reticulocyte count, or RBC xerocytosis. HbC-driven oxidative denaturation and membrane damage represent important contributors of RBC dysfunction in HbSC disease; hence, oxidative membrane injury could be targeted besides antisickling approaches.

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Setayesh, T., Tijani, A., Kaur, H., Khanal, S., Zhu, Z., Oestreicher, Z., Sue, K., Balla, J., Chi, M., Ware, R. E., Malik, P.. 2026-06-10. Hemoglobin C is prone to oxidative denaturation, resulting in red blood cell membrane damage in HbSC disease. https://doi.org/10.64898/2026.06.05.729662

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