Methylglyoxal induces chromosomal instability and mitotic dysfunction in lymphocytes

Area of Science:

• Genetics and Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Type 2 diabetes is linked to increased DNA damage, specifically micronuclei (MNi), which arise from chromosome fragments or whole chromosome mis-segregation.
• Methylglyoxal (MGO), a reactive dicarbonyl compound, is found at elevated levels in type 2 diabetes and is implicated in cellular damage.

Purpose of the Study:

• To investigate if methylglyoxal (MGO) increases chromosomal instability and DNA damage.
• To assess MGO's genotoxic effects using the cytokinesis-block micronucleus cytome (CBMNcyt) assay in human cell lines.
• To examine MGO's role in DNA damage and chromosome segregation during mitosis.

Main Methods:

• Exposure of B-lymphoblastoid WIL2-NS cells and primary peripheral blood lymphocytes (PBL) to MGO or a glyoxalase 1 inhibitor.
• Measurement of DNA damage using the cytokinesis-block micronucleus cytome (CBMNcyt) assay, quantifying micronuclei (MNi) and nuclear buds.
• Analysis of MGO levels and DNA modifications, and use of fluorescent in situ hybridization (FISH) to determine MNi formation mechanisms.

Main Results:

• MGO exposure increased micronuclei (MNi) and nuclear buds in WIL2-NS cells, correlating with higher intracellular MGO levels.
• Primary PBL exposed to MGO showed DNA damage, including MNi and nucleoplasmic bridges, indicating MGO's genotoxicity at low concentrations.
• Fluorescent in situ hybridization revealed that MGO-induced MNi in WIL2-NS cells primarily resulted from whole chromosome loss, not double-stranded DNA breaks (DSBs).

Conclusions:

• Methylglyoxal (MGO), elevated in type 2 diabetes, demonstrably increases chromosomal instability and DNA damage.
• MGO impairs chromosome segregation during mitosis, leading to genomic instability.
• These findings highlight MGO as a significant contributor to DNA damage and genomic integrity disruption in type 2 diabetes and other conditions.