Gangliosides induce autophagic cell death in astrocytes.
OBJECTIVE
Gangliosides, sialic acid-containing glycosphingolipids, abundant in brain, are involved in neuronal function and disease, but the precise molecular mechanisms underlying their physiological or pathological activities are poorly understood. In this study, the pathological role of gangliosides in the extracellular milieu with respect to glial cell death and lipid raft/membrane disruption was investigated.


METHODS
We determined the effect of gangliosides on astrocyte death or survival using primary astrocyte cultures and astrocytoma/glioma cell lines as a model. Signalling pathways of ganglioside-induced autophagic cell death of astrocytes were examined using pharmacological inhibitors and biochemical and genetic assays.


RESULTS
Gangliosides induced autophagic cell death in based on the following observations. Incubation of the cells with a mixture of gangliosides increased a punctate distribution of fluorescently labelled microtubule-associated protein 1 light chain 3 (GFP-LC3), the ratio of LC3-II/LC3-I and LC3 flux. Gangliosides also increased the formation of autophagic vacuoles as revealed by monodansylcadaverine staining. Ganglioside-induced cell death was inhibited by either a knockdown of beclin-1/Atg-6 or Atg-7 gene expression or by 3-methyladenine, an inhibitor of autophagy. Reactive oxygen species (ROS) were involved in ganglioside-induced autophagic cell death of astrocytes, because gangliosides induced ROS production and ROS scavengers decreased autophagic cell death. In addition, lipid rafts played an important role in ganglioside-induced astrocyte death.


CONCLUSIONS
Gangliosides released under pathological conditions may induce autophagic cell death of astrocytes, identifying a neuropathological role for gangliosides.
Hwang
Jaegyu
J
Department of Pharmacology, School of Medicine, Brain Science and Engineering Institute, CMRI, Kyungpook National University, Daegu, Korea.
Lee
Shinrye
S
Lee
Jung Tae
JT
Kwon
Taeg Kyu
TK
Kim
Deok Ryong
DR
Kim
Ho
H
Park
Hae-Chul
HC
Suk
Kyoungho
K
D000225:Adenine / Q000031:analogs & derivatives; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001343:Autophagy / Q000187:drug effects* / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D005732:Gangliosides / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008247:Lysosomes / Q000378:metabolism / Q000473:pathology; D008869:Microtubule-Associated Proteins / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects
D005732:Gangliosides; D008869:Microtubule-Associated Proteins; D017382:Reactive Oxygen Species; C025946:3-methyladenine; D000225:Adenine