Novel method utilizing bisulfite conversion with dual amplification-refractory mutation system polymerase chain...

Area of Science:

• Endocrinology
• Molecular Biology
• Diabetes Research

Background:

• Quantifying pancreatic beta cell (β-cell) injury is crucial for understanding diabetes.
• Existing methods for detecting β-cell-specific CpG unmethylation of insulin gene face challenges like background noise and specialized equipment needs.

Purpose of the Study:

• To develop a novel, accessible method for quantifying β-cell injury by detecting unmethylated insulin DNA in circulation.
• To overcome limitations of current techniques like digital droplet PCR and next-generation sequencing.

Main Methods:

• Established a two-step amplification refractory mutation system PCR for detecting four CpG unmethylations of the insulin gene.
• Applied the novel assay to type 1 diabetes (T1D) patients and healthy adults.

Main Results:

• The assay demonstrated high linearity and sensitivity, detecting single copies of unmethylated insulin DNA.
• Circulating unmethylated insulin DNA levels were similar in T1D patients and healthy adults, despite reduced β-cell mass in T1D.
• An inverse correlation was found between unmethylated insulin DNA copy number and disease duration in T1D patients.

Conclusions:

• A novel method for detecting circulating unmethylated insulin DNA was successfully developed.
• The method utilizes conventional real-time PCR, making it broadly accessible.
• This technique is valuable for analyzing dynamic β-cell profiles in human diseases like type 1 diabetes.