Alice Maestri (Sweden)

Karolinska Institutet Medicine Solna (MedS)
Alice Maestri is a PhD candidate in Prof. Ehrenborg's laboratory in the Department of Medicine at Karolinska Institutet. Prior, Alice received her bachelor and master’s degree in pharmacology from UCL, focusing on generating a patient-specific bioreactor grown artificial liver model for personalised gene therapy. Her current research focuses on elucidating the crosstalk between lipid metabolism and autophagy in diseases of ageing, using a genetic approach. Her research aim is to find new targets related to longevity to improve and maintain quality of life as we age.

Author Of 1 Presentation

O051 - The crosstalk between macroautophagy and chaperone-mediated autophagy (CMA) is influenced by the lipid droplet-associated protein perilipin 2 (PLIN2) during lipophagy (ID 467)

Session Type
Genetics
Session Time
14:30 - 16:00
Date
Tue, 01.06.2021
Room
Hall D
Lecture Time
15:12 - 15:20

Abstract

Background and Aims

PLIN2 is the most prominent lipid droplet (LD)-associated protein in foam cells. PLIN2 stabilizes LDs and LDs protect PLIN2 from rapid degradation. LD-bound PLIN2 degradation is dependent on AMPK-phosphorylation via chaperone-mediated autophagy (CMA). PLIN2 is vital to maintain certain LD size and number. We have recently shown that the Ser251Pro SNP in PLIN2 influences macroautophagy, cholesterol efflux, cholesterol accumulation and is associated with subclinical atherosclerosis development in humans. Since a direct crosstalk between macroautophagy and CMA has been proposed, we aim to investigate whether the Ser251Pro SNP affects CMA and the degradation of PLIN2, thereby influencing lipophagy.

Methods

We utilized stably transfected HEK293 cells carrying either variant of PLIN2 loaded with oleate, followed by treatment with AMPK modulators: we measured PLIN2 and L2A levels by WB and colocalization of Hsc70/L2A by IHC. We used WT, ATG5-/- and L2A-/- MEF cells transiently transfected with PLIN2 variants: we measured LD number by IHC, PLIN2 levels by WB.

Results

Ser251Pro-dependent differences in lipid accumulation observed in WT MEF cells are abolished in both ATG5-/- and L2A-/- MEF cells. Cells carrying the Pro251 allele show lower L2A expression and less Hsc70/L2A colocalization, indicating fewer CMA-active lysosomes. Further, AMPK inhibition in HEK cells induces PLIN2 expression more in Ser251- than in Pro251-carrying cells.

Conclusions

The effect of the Ser251Pro SNP on lipid accumulation is dependent on both macroautophagy and CMA. The presence of the Pro251 allele reduces CMA-activity and modifies PLIN2 degradation via AMPK. Thus, PLIN2 influences lipophagy via crosstalk between macroautophagy and CMA.

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Presenter of 1 Presentation

O051 - The crosstalk between macroautophagy and chaperone-mediated autophagy (CMA) is influenced by the lipid droplet-associated protein perilipin 2 (PLIN2) during lipophagy (ID 467)

Session Type
Genetics
Session Time
14:30 - 16:00
Date
Tue, 01.06.2021
Room
Hall D
Lecture Time
15:12 - 15:20

Abstract

Background and Aims

PLIN2 is the most prominent lipid droplet (LD)-associated protein in foam cells. PLIN2 stabilizes LDs and LDs protect PLIN2 from rapid degradation. LD-bound PLIN2 degradation is dependent on AMPK-phosphorylation via chaperone-mediated autophagy (CMA). PLIN2 is vital to maintain certain LD size and number. We have recently shown that the Ser251Pro SNP in PLIN2 influences macroautophagy, cholesterol efflux, cholesterol accumulation and is associated with subclinical atherosclerosis development in humans. Since a direct crosstalk between macroautophagy and CMA has been proposed, we aim to investigate whether the Ser251Pro SNP affects CMA and the degradation of PLIN2, thereby influencing lipophagy.

Methods

We utilized stably transfected HEK293 cells carrying either variant of PLIN2 loaded with oleate, followed by treatment with AMPK modulators: we measured PLIN2 and L2A levels by WB and colocalization of Hsc70/L2A by IHC. We used WT, ATG5-/- and L2A-/- MEF cells transiently transfected with PLIN2 variants: we measured LD number by IHC, PLIN2 levels by WB.

Results

Ser251Pro-dependent differences in lipid accumulation observed in WT MEF cells are abolished in both ATG5-/- and L2A-/- MEF cells. Cells carrying the Pro251 allele show lower L2A expression and less Hsc70/L2A colocalization, indicating fewer CMA-active lysosomes. Further, AMPK inhibition in HEK cells induces PLIN2 expression more in Ser251- than in Pro251-carrying cells.

Conclusions

The effect of the Ser251Pro SNP on lipid accumulation is dependent on both macroautophagy and CMA. The presence of the Pro251 allele reduces CMA-activity and modifies PLIN2 degradation via AMPK. Thus, PLIN2 influences lipophagy via crosstalk between macroautophagy and CMA.

Hide