Metformin modulates autophagy in heterozygous and CRISPR-edited TSC2 primary fibroblasts
Abstract
Background: Tuberous Sclerosis Complex (TSC) is a genetic disorder caused by variants in TSC1 or TSC2, leading to mTORC1 hyperactivation and autophagy suppression. Although TSC tumorigenesis typically follows a “two-hit” model, the role of TSC2 haploinsufficiency in autophagy regulation remains unclear. We evaluated autophagy markers in haploinsufficient and gene-edited TSC2 primary cells and investigated the role of metformin in modulating autophagy levels.
Methods: Primary fibroblast cultures were obtained from one healthy individual and three from patients carrying heterozygous germline TSC2 variants: the pathogenic variants c.1008T>G and c.4375C>T.A variant of uncertain significance (VUS) c.724A>T. CRISPR/Cas9-RNP editing was used to model loss of heterozygosity (LOH) in cell pools carrying each variant. Cultures were treated with rapamycin, HBSS, metformin, bafilomycin A1, or vehicle controls, and autophagy was assessed by autolysosomes formation by flow cytometry (acridine orange) and autophagosomes immunofluorescence (LC3 and p-S6K).
Results: In wild-type cells, only HBSS increased autophagy-positive (acridine orange-positive) cells versus control (15.6% vs. 7.5%; p=0.003). In heterozygous pathogenic cells, rapamycin and metformin increased autophagic cells: c.1008T>G (16.2%, p=0.006; 17.6%, p=0.002) and c.4375C>T (12.5%, p=0.003; 13.3%, p=0.001), versus DMSO controls (9.2% and 7.1%, respectively). VUS c.724A>T cells, with rapamycin increasing autophagic cells (9.74%…
Read the paper
Related studies
- Metformin as an adjuvant in breast cancer treatment
- Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?
- Aberrant HSF1 signaling activation underlies metformin amelioration of myocardial infarction in mice
- Metformin induces ZFP36 by mTORC1 inhibition in cervical cancer-derived cell lines
- Protein Interaction Network for Identifying Vascular Response of Metformin (Oral Antidiabetic)
- Preventing Long COVID With Metformin
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.