Golgi fragmentation is associated with ceramide-induced cellular effects

Area of Science:

• Cell Biology
• Biochemistry
• Apoptosis Research

Background:

• Ceramide is known to induce anoikis, a form of apoptosis linked to cell adhesion loss.
• The precise molecular mechanisms driving ceramide-induced anoikis remain incompletely understood.

Purpose of the Study:

• To elucidate the mechanism by which D-e-C6-ceramide (D-e-Cer) triggers anoikis.
• To investigate the role of sphingosine and the Golgi complex in ceramide-mediated cellular responses.

Main Methods:

• Treatment of HeLa cells with D-e-Cer and its enantiomer L-e-Cer.
• Analysis of cellular morphology, cytoskeletal organization, and protein glycosylation.
• Mass spectrometry to quantify sphingosine levels.
• Treatment with D-e-sphingosine and L-e-sphingosine.

Main Results:

• D-e-Cer induced cell elongation, spreading inhibition, rounding, detachment, and apoptosis (anoikis).
• Sphingosine generation from D-e-Cer hydrolysis correlated with Golgi complex fragmentation and disruption.
• Inhibition of beta1 integrin glycosylation and cell surface translocation was observed.
• Cytoskeletal reorganization, focal adhesion, and filopodia formation were impaired.
• L-e-Cer and sphingosine enantiomers did not induce these effects, highlighting stereospecificity.

Conclusions:

• Sphingosine, generated from D-e-Cer hydrolysis, is the key mediator of Golgi complex disruption.
• Golgi complex disruption by sphingosine leads to impaired integrin function and cytoskeletal dynamics, ultimately causing anoikis.
• These findings reveal a novel mechanism for ceramide-induced anoikis involving sphingolipid metabolism and organelle integrity.