Visualizing red blood cell sickling and the effects of inhibition of sphingosine kinase 1 using soft X-ray tomography

J Cell Sci. 2016 Sep 15;129(18):3511-7. doi: 10.1242/jcs.189225. Epub 2016 Aug 9.


Sickle cell disease is a destructive genetic disorder characterized by the formation of fibrils of deoxygenated hemoglobin, leading to the red blood cell (RBC) morphology changes that underlie the clinical manifestations of this disease. Using cryogenic soft X-ray tomography (SXT), we characterized the morphology of sickled RBCs in terms of volume and the number of protrusions per cell. We were able to identify statistically a relationship between the number of protrusions and the volume of the cell, which is known to correlate to the severity of sickling. This structural polymorphism allows for the classification of the stages of the sickling process. Recent studies have shown that elevated sphingosine kinase 1 (Sphk1)-mediated sphingosine 1-phosphate production contributes to sickling. Here, we further demonstrate that compound 5C, an inhibitor of Sphk1, has anti-sickling properties. Additionally, the variation in cellular morphology upon treatment suggests that this drug acts to delay the sickling process. SXT is an effective tool that can be used to identify the morphology of the sickling process and assess the effectiveness of potential therapeutics.

Keywords: Cryogenic soft X-ray tomography; Red blood cell; Red cell morphology; Sickle cell disease; Sphingosine kinase inhibitor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anemia, Sickle Cell / enzymology*
  • Animals
  • Cell Surface Extensions / drug effects
  • Cell Surface Extensions / metabolism
  • Erythrocytes / drug effects
  • Erythrocytes / enzymology*
  • Humans
  • Mice
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Protein Kinase Inhibitors / pharmacology
  • Tomography, X-Ray / methods*


  • Protein Kinase Inhibitors
  • Phosphotransferases (Alcohol Group Acceptor)
  • sphingosine kinase