Sulfhydryl reducing agents and shape regulation in human erythrocytes

Area of Science:

• Hematology
• Cell Biology
• Biochemistry

Background:

• Metabolic crenation of red blood cells (echinocytes) is reversible upon nutrient addition.
• Reducing agents, such as dithiothreitol (DTT), can influence red blood cell shape recovery.

Purpose of the Study:

• To investigate the effect of dithiothreitol (DTT) on red blood cell shape recovery from echinocyte morphology.
• To determine the mechanism by which DTT induces stomatocytosis in red blood cells.

Main Methods:

• Red blood cells were induced into echinocyte forms and then treated with nutrients and/or dithiothreitol (DTT).
• Morphological changes were observed under varying conditions of DTT presence and absence.
• Adenosine triphosphate (ATP) synthesis, glutathione levels, and spectrin phosphorylation were assessed.
• Phosphorylation of membrane inner monolayer lipids was analyzed.

Main Results:

• Dithiothreitol (DTT) promotes a shift from echinocyte to stomatocyte morphology in red blood cells.
• The degree of stomatocytosis is dependent on the initial cell morphology and continuous presence of DTT.
• DTT does not affect ATP synthesis, glutathione levels, or spectrin phosphorylation.
• DTT-induced stomatocytosis is linked to the phosphorylation of inner monolayer lipids, but overphosphorylation is not the cause.

Conclusions:

• Dithiothreitol (DTT) induces a unique stomatocytic shape in red blood cells during shape recovery.
• The mechanism involves lipid phosphorylation, independent of ATP synthesis or spectrin phosphorylation.
• Continuous presence of DTT is essential for the development and maintenance of DTT-induced stomatocytosis.