Less-deformable erythrocyte subpopulations biomechanically induce endothelial inflammation in sickle cell disease

• Published in: Blood Vol. 144; no. 19; pp. 2050 - 2062
• Main Authors: Caruso, Christina, Cheng, Xiaopo, Michaud, Marina E., Szafraniec, Hannah M., Thomas, Beena E., Fay, Meredith E., Mannino, Robert G., Zhang, Xiao, Sakurai, Yumiko, Li, Wei, Myers, David R., Joiner, Clinton H., Wood, David K., Bhasin, Manoj, Graham, Michael D., Lam, Wilbur A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 07.11.2024
• Subjects: Anemia, Sickle Cell - blood; Anemia, Sickle Cell - pathology; Endothelial Cells - metabolism; Endothelial Cells - pathology; Endothelium, Vascular - metabolism; Endothelium, Vascular - pathology; Erythrocyte Deformability; Erythrocytes - metabolism; Erythrocytes - pathology; Erythrocytes, Abnormal - metabolism; Erythrocytes, Abnormal - pathology; Humans; Inflammation - pathology; Mechanotransduction, Cellular
• ISSN: 0006-4971; 1528-0020; 1528-0020
• DOI: 10.1182/blood.2024024608

•Less-deformable sickle red cells marginate toward blood vessel walls, leading to altered local wall shear stress and endothelial dysfunction.•Pathological biophysical alterations in sickle RBCs cause endothelial dysfunction independently from vaso-occlusion and adhesion. [Display omitted] Sickle cell disease (SCD) is canonically characterized by reduced red blood cell (RBC) deformability, leading to microvascular obstruction and inflammation. Although the biophysical properties of sickle RBCs are known to influence SCD vasculopathy, the contribution of poor RBC deformability to endothelial dysfunction has yet to be fully explored. Leveraging interrelated in vitro and in silico approaches, we introduce a new paradigm of SCD vasculopathy in which poorly deformable sickle RBCs directly cause endothelial dysfunction via mechanotransduction, during which endothelial cells sense and pathophysiologically respond to aberrant physical forces independently of microvascular obstruction, adhesion, or hemolysis. We demonstrate that perfusion of sickle RBCs or pharmacologically-dehydrated healthy RBCs into small venule-sized “endothelialized” microfluidics leads to pathologic physical interactions with endothelial cells that directly induce inflammatory pathways. Using a combination of computational simulations and large venule-sized endothelialized microfluidics, we observed that perfusion of heterogeneous sickle RBC subpopulations with varying deformability, as well as suspensions of dehydrated normal RBCs admixed with normal RBCs, leads to aberrant margination of the less-deformable RBC subpopulations toward the vessel walls, causing localized, increased shear stress. Increased wall stress is dependent on the degree of subpopulation heterogeneity and oxygen tension and leads to inflammatory endothelial gene expression via mechanotransductive pathways. Our multifaceted approach demonstrates that the presence of sickle RBCs with reduced deformability leads directly to pathological physical (ie, direct collisions and/or compressive forces) and shear-mediated interactions with endothelial cells and induces an inflammatory response, thereby elucidating the ubiquity of vascular dysfunction in SCD. Sickle cell disease (SCD) is associated with decreased red blood cell (RBC) deformability, leading to microvascular obstruction and inflammation. Caruso and colleagues investigated the contribution of RBCs with impaired deformability to vasculopathy. Their results suggest that rigid RBCs are abnormally marginated in small vessels, causing localized increased shear stress, increased inflammatory gene expression by endothelial cells, and inflammation-associated vascular dysfunction.