Sickle cell disease (SCD) is a genetic disorder characterized by abnormal hemoglobin molecules in red blood cells, leading to vaso-occlusive events and tissue damage. Tumor necrosis factor (TNF) is a pro-inflammatory cytokine implicated in the pathogenesis of SCD-associated complications. This study explores the potential of recombinant Marmota monax TNF (rMmTNF) as a therapeutic agent in SCD management. Using a murine model of SCD, we investigated the effects of rMmTNF on inflammatory markers, red blood cell deformability, and endothelial cell activation. Our findings suggest that rMmTNF modulates inflammatory responses and may mitigate vaso-occlusive crises in SCD, highlighting its therapeutic potential. Further studies are warranted to elucidate the precise mechanisms and evaluate the clinical efficacy of rMmTNF in human SCD patients.
Sickle cell disease (SCD) affects millions worldwide, primarily those of African descent. The disease results from a single point mutation in the β-globin gene, leading to the production of abnormal hemoglobin S (HbS). Polymerization of HbS under low oxygen conditions causes red blood cells to become rigid and assume a sickle shape, promoting vaso-occlusive events and tissue ischemia. In addition to hemolysis and chronic inflammation, vaso-occlusive crises (VOCs) are hallmark features of SCD, contributing to substantial morbidity and mortality.
Tumor necrosis factor (TNF)
Is a pleiotropic cytokine produced by activated macrophages and other cells in response to inflammatory stimuli. TNF plays a crucial role in immune regulation and inflammation. Elevated levels of TNF have been implicated in the pathophysiology of various inflammatory diseases, including rheumatoid arthritis, Crohn's disease, and SCD. In SCD patients, TNF levels are often elevated during VOCs and correlate with disease severity.
Given its role in inflammation and endothelial activation, TNF represents a potential therapeutic target in SCD. Recombinant TNF derived from the North American groundhog (Marmota monax), termed rMmTNF, has shown promise in preclinical models of inflammatory diseases due to its structural and functional similarities to human TNF.
To investigate the therapeutic potential of rMmTNF in SCD, we utilized a transgenic murine model expressing human sickle hemoglobin (HbSS mice). Mice were treated with recombinant rMmTNF via intravenous injection at doses ranging from 1 to 10 mg/kg body weight. Control groups received saline or vehicle injections.
Key outcomes measured included:
- Inflammatory markers: Serum levels of inflammatory cytokines (e.g., IL-6, IL-1β) were quantified using ELISA.
- Red blood cell (RBC) deformability: RBCs isolated from treated mice were assessed for deformability using ektacytometry.
- Endothelial cell activation: Expression of adhesion molecules (e.g., VCAM-1, ICAM-1) on endothelial cells was analyzed by flow cytometry.
Treatment with rMmTNF resulted in a dose-dependent reduction in serum levels of inflammatory cytokines, including TNF, IL-6, and IL-1β. This reduction was accompanied by improvements in RBC deformability, indicative of reduced sickling under hypoxic conditions. Furthermore, rMmTNF attenuated endothelial cell activation, as evidenced by decreased expression of adhesion molecules involved in leukocyte recruitment and vascular occlusion.
Our findings suggest that rMmTNF holds promise as a therapeutic agent for managing SCD-associated complications. By modulating inflammatory responses and improving RBC deformability, rMmTNF may mitigate the severity of vaso-occlusive crises and reduce endothelial dysfunction in SCD. Future studies should focus on elucidating the underlying mechanisms of rMmTNF action and evaluating its safety and efficacy in clinical trials involving SCD patients