Mitochondria-targeted inhibitors of the human SIRT3 lysine deacetylase

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Sirtuin 3 (SIRT3) is a key mitochondrial deacetylase regulating metabolic enzymes.
• SIRT3 is a potential therapeutic target for cancers, but selective inhibitors are lacking.
• SIRT1 and SIRT2 are structurally similar isozymes located in the nucleus and cytosol, respectively.

Purpose of the Study:

• To develop potent and selective inhibitors for Sirtuin 3 (SIRT3).
• To achieve mitochondrial localization of inhibitors, distinguishing SIRT3 from SIRT1 and SIRT2.
• To enable detailed investigation of SIRT3's role in cellular processes and disease.

Main Methods:

• Incorporation of mitochondria-targeting peptide sequences into inhibitor structures.
• Assessment of mitochondrial localization using fluorophore-conjugated inhibitors in HeLa cells.
• Target engagement confirmed via cellular thermal shift assay (CETSA) and western blotting.
• Evaluation of compound selectivity by measuring the acetylation state of SIRT3 target MnSOD and known targets of SIRT1/SIRT2.

Main Results:

• Inhibitors demonstrated excellent mitochondrial localization in HeLa cells.
• Successful target engagement of SIRT3 was confirmed.
• The lead compound selectively increased MnSOD acetylation, a known SIRT3 substrate.
• Minimal impact on known targets of SIRT1 and SIRT2 indicated high selectivity.

Conclusions:

• A novel strategy for selective mitochondrial SIRT3 inhibition in cells was successfully developed.
• The developed inhibitors facilitate detailed investigation into SIRT3's biological functions.
• This advancement supports the exploration of SIRT3 as a viable drug target for various conditions, including cancer.