Molecular pathways dysregulated by Pb²⁺ exposure prompts pancreatic beta-cell dysfunction

Area of Science:

• Environmental toxicology
• Endocrinology
• Metabolic diseases

Background:

• Type 2 diabetes mellitus (T2DM) is a growing global health concern, influenced by genetics, lifestyle, and environmental factors.
• Xenobiotics and heavy metals are implicated as potential contributors to T2DM pathogenesis.
• Understanding environmental triggers like lead exposure is crucial for T2DM prevention and management.

Purpose of the Study:

• To investigate the link between lead (Pb²⁺) exposure and type 2 diabetes mellitus.
• To elucidate the mechanisms by which Pb²⁺ induces pancreatic β-cell dysfunction.
• To identify Pb²⁺ as a potential diabetogenic environmental factor.

Main Methods:

• In vivo studies to assess the impact of Pb²⁺ exposure on glucose-stimulated insulin secretion and pancreatic β-cell mass.
• Mechanistic investigations into Pb²⁺ effects on intracellular cAMP levels, phosphodiesterase 1C activity, mitochondrial ATP production, and β-cell proliferation pathways (Ca²⁺/calmodulin-dependent protein kinase kinases-pAMPK-pRaptor axis).

Main Results:

• Pb²⁺ exposure significantly reduced glucose-stimulated insulin secretion and diminished functional pancreatic β-cell mass.
• Pb²⁺ downregulates intracellular cAMP by activating phosphodiesterase 1C, impairing insulin secretion.
• Pb²⁺ inhibits mitochondrial ATP production and negatively regulates β-cell proliferation via the Ca²⁺/calmodulin-dependent protein kinase kinases-pAMPK-pRaptor pathway.
• Pb²⁺ mimics calcium ions, disrupting normal pancreatic β-cell function.

Conclusions:

• Pb²⁺ exposure is a significant risk factor for type 2 diabetes mellitus.
• Lead disrupts pancreatic β-cell function and survival through multiple molecular mechanisms.
• Pb²⁺ acts as a diabetogenic xenobiotic by interfering with calcium signaling and cellular metabolism in pancreatic β-cells.