SNAP23 regulates BAX-dependent adipocyte programmed cell death independently of canonical macroautophagy

Daorong Feng, Dulguun Amgalan, Rajat Singh, Jianwen Wei, Jennifer Wen, Tszki Peter Wei, Timothy E. McGraw, Richard N. Kitsis, Jeffrey E. Pessin

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The t-SNARE protein SNAP23 conventionally functions as a component of the cellular machinery required for intracellular transport vesicle fusion with target membranes and has been implicated in the regulation of fasting glucose levels, BMI, and type 2 diabetes. Surprisingly, we observed that adipocyte-specific KO of SNAP23 in mice resulted in a temporal development of severe generalized lipodystrophy associated with adipose tissue inflammation, insulin resistance, hyperglycemia, liver steatosis, and early death. This resulted from adipocyte cell death associated with an inhibition of macroautophagy and lysosomal degradation of the proapoptotic regulator BAX, with increased BAX activation. BAX colocalized with LC3-positive autophagic vacuoles and was increased upon treatment with lysosome inhibitors. Moreover, BAX deficiency suppressed the lipodystrophic phenotype in the adipocyte-specific SNAP23-KO mice and prevented cell death. In addition, ATG9 deficiency phenocopied SNAP23 deficiency, whereas ATG7 deficiency had no effect on BAX protein levels, BAX activation, or apoptotic cell death. These data demonstrate a role for SNAP23 in the control of macroautophagy and programmed cell death through an ATG9-dependent, but ATG7-independent, pathway regulating BAX protein levels and BAX activation.

Original languageEnglish (US)
Pages (from-to)3941-3956
Number of pages16
JournalJournal of Clinical Investigation
Volume128
Issue number9
DOIs
StatePublished - Aug 31 2018

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Autophagy
Adipocytes
Cell Death
SNARE Proteins
Congenital Generalized Lipodystrophy
Transport Vesicles
Fatty Liver
Vacuoles
Lysosomes
Hyperglycemia
Type 2 Diabetes Mellitus
Insulin Resistance
Adipose Tissue
Fasting
Proteins
Inflammation
Phenotype
Glucose
Membranes

ASJC Scopus subject areas

  • Medicine(all)

Cite this

SNAP23 regulates BAX-dependent adipocyte programmed cell death independently of canonical macroautophagy. / Feng, Daorong; Amgalan, Dulguun; Singh, Rajat; Wei, Jianwen; Wen, Jennifer; Wei, Tszki Peter; McGraw, Timothy E.; Kitsis, Richard N.; Pessin, Jeffrey E.

In: Journal of Clinical Investigation, Vol. 128, No. 9, 31.08.2018, p. 3941-3956.

Research output: Contribution to journalArticle

Feng, Daorong ; Amgalan, Dulguun ; Singh, Rajat ; Wei, Jianwen ; Wen, Jennifer ; Wei, Tszki Peter ; McGraw, Timothy E. ; Kitsis, Richard N. ; Pessin, Jeffrey E. / SNAP23 regulates BAX-dependent adipocyte programmed cell death independently of canonical macroautophagy. In: Journal of Clinical Investigation. 2018 ; Vol. 128, No. 9. pp. 3941-3956.
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abstract = "The t-SNARE protein SNAP23 conventionally functions as a component of the cellular machinery required for intracellular transport vesicle fusion with target membranes and has been implicated in the regulation of fasting glucose levels, BMI, and type 2 diabetes. Surprisingly, we observed that adipocyte-specific KO of SNAP23 in mice resulted in a temporal development of severe generalized lipodystrophy associated with adipose tissue inflammation, insulin resistance, hyperglycemia, liver steatosis, and early death. This resulted from adipocyte cell death associated with an inhibition of macroautophagy and lysosomal degradation of the proapoptotic regulator BAX, with increased BAX activation. BAX colocalized with LC3-positive autophagic vacuoles and was increased upon treatment with lysosome inhibitors. Moreover, BAX deficiency suppressed the lipodystrophic phenotype in the adipocyte-specific SNAP23-KO mice and prevented cell death. In addition, ATG9 deficiency phenocopied SNAP23 deficiency, whereas ATG7 deficiency had no effect on BAX protein levels, BAX activation, or apoptotic cell death. These data demonstrate a role for SNAP23 in the control of macroautophagy and programmed cell death through an ATG9-dependent, but ATG7-independent, pathway regulating BAX protein levels and BAX activation.",
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