Glucose shields RINm5F beta cells against arsenic-induced apoptosis

Area of Science:

• Endocrinology
• Toxicology
• Cell Biology

Background:

• Type 2 Diabetes (T2D) involves hyperglycemia, beta-cell dysfunction, and insulin resistance.
• Arsenic exposure and high carbohydrate intake are T2D risk factors, but their interaction mechanisms are unclear.
• Understanding these interactions is crucial for elucidating beta-cell apoptosis pathways.

Purpose of the Study:

• To investigate the effects of arsenic and glucose on beta-cell apoptosis.
• To explore the underlying mechanisms involving insulin signaling pathways.
• To determine if glucose co-treatment affects arsenic-induced beta-cell apoptosis.

Main Methods:

• In vitro exposure of RINm5F insulinoma beta-cells to arsenic (As), glucose (Gluc), and their combination (As + Gluc) for 48 and 72 hours.
• Analysis of apoptosis using flow cytometry and assessment of key signaling pathways (PI3K/Akt, MAPK).
• Measurement of calpain activity and Bax/Caspase-3 pathway markers.

Main Results:

• Arsenic alone induced early apoptosis in beta-cells.
• Glucose co-treatment reduced arsenic-induced apoptosis.
• As + Gluc altered insulin signaling, increasing Akt/S6K1 activation and decreasing ERK1/2 activation.
• Increased calpain activity and down-regulation of the Bax/Caspase-3 pathway were observed with As + Gluc compared to As alone.

Conclusions:

• Glucose co-treatment mitigates the pro-apoptotic effects of arsenic in beta-cells.
• Calpains play a significant role in this protective response.
• The Akt/S6K1 signaling axis is notably altered, suggesting its involvement in the protective mechanism against arsenic toxicity.