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Ferrata Storti Foundation
Haematologica 2022 Volume 107(2):532-540
Sulfated non-anticoagulant heparin derivative modifies intracellular hemoglobin, inhibits cell sickling in vitro, and prolongs survival of sickle cell mice under hypoxia
Osheiza Abdulmalik,1* Noureldien H. E. Darwish,2,3*
Vandhana Muralidharan-Chari,2° Maii Abu Taleb2 and Shaker A. Mousa2,4
1Division of Hematology, the Children’s Hospital of Philadelphia, Philadelphia, PA, USA; 2The Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Rensselaer, NY, USA; 3Clinical Pathology (Hematology Section), Faculty of Medicine, Mansoura University, Mansoura, Egypt and 4Vascular Vison Pharmaceuticals Co., Rensselaer, NY, USA
*OA and NHED contributed equally as co-first authors.
°Current address: College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY, USA.
ABSTRACT
Sickle cell disease (SCD) is an autosomal recessive genetic disease caused by a single point mutation, resulting in abnormal sickle hemoglobin (HbS). During hypoxia or dehydration, HbS polymer- izes to form insoluble aggregates and induces sickling of red blood cells, which increases the adhesiveness of the cells, thereby altering the rheo- logical properties of the blood, and triggers inflammatory responses, lead- ing to hemolysis and vaso-occlusive crises. Unfractionated heparin and low-molecular weight heparins have been suggested as treatments to relieve coagulation complications in SCD. However, they are associated with bleeding complications after repeated dosing. An alternative sulfat- ed non-anticoagulant heparin derivative (S-NACH) was previously reported to have no to low systemic anticoagulant activity and no bleed- ing side effects, and it interfered with P-selectin-dependent binding of sickle cells to endothelial cells, with concomitant decrease in the levels of adhesion biomarkers in SCD mice. S-NACH has been further engineered and structurally enhanced to bind with and modify HbS to inhibit sick- ling directly, thus employing a multimodal approach. Here, we show that S-NACH can: (i) directly engage in Schiff-base reactions with HbS to decrease red blood cell sickling under both normoxia and hypoxia in vitro, (ii) prolong the survival of SCD mice under hypoxia, and (iii) regulate the altered steady state levels of pro- and anti-inflammatory cytokines. Thus, our proof-of-concept, in vitro and in vivo preclinical studies demonstrate that the multimodal S-NACH is a highly promising candidate for devel- opment into an improved and optimized alternative to low-molecular weight heparins for the treatment of patients with SCD.
Introduction
Sickle cell disease (SCD) is a hemoglobinopathy resulting from a mutation replac- ing the glutamic acid amino acid with the less polar valine amino acid at the sixth position of the b chain, converting normal adult hemoglobin (HbA) to sickle hemo- globin (HbS).1 Deoxygenated HbS polymerizes into long, rigid fibers, causing sick- ling of red blood cells (RBC).2 These characteristic sickled RBC impair blood flow through the microvasculature, leading to hemolysis, episodes of vaso-occlusion, and multi-organ damage.3-7 The loss of membrane phospholipid asymmetry on sickled RBC exposes phosphatidylserines8 that increase the adhesion of sickled RBC to neutrophils, monocytes, platelets, and endothelial cells to activate coagula- tion and inflammatory pathways,9-12 culminating in a ‘hypercoagulable’ state.13
Red Cell Biology & its Disorders
Currently, four drugs have been approved by the Food and Drug Administration
Correspondence:
SHAKER A. MOUSA
shaker.mousa@acphs.edu
Received: September 15, 2020. Accepted: January 25, 2021. Pre-published: February 11, 2021.
https://doi.org/10.3324/haematol.2020.272393 ©2022 Ferrata Storti Foundation
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