Antisense DNA downregulates protein kinase C isozymes (beta and alpha) and insulin-stimulated 2-deoxyglucose uptake in rat adipocytes

Area of Science:

• Molecular biology
• Cell signaling
• Metabolic research

Background:

• Protein kinase C (PKC) is involved in cellular signaling pathways.
• Insulin stimulates glucose uptake in adipocytes, a process crucial for glucose homeostasis.
• Specific isozymes of PKC may play distinct roles in insulin signaling.

Purpose of the Study:

• To investigate the role of specific protein kinase C (PKC) isozymes in insulin-stimulated glucose transport in rat adipocytes.
• To determine if antisense oligodeoxynucleotides can selectively downregulate PKC isozymes.
• To elucidate the contribution of PKC to insulin action on glucose uptake.

Main Methods:

• Treatment of rat adipocytes with antisense dimethoxytrityl pentadecadeoxynucleotides targeting mRNA initiation sites for PKC-alpha and PKC-beta.
• Measurement of PKC levels and protein kinase C activity.
• Assay of insulin-stimulated 2-deoxyglucose uptake.
• Assessment of insulin-stimulated diacylglycerol synthesis.

Main Results:

• Antisense treatment resulted in a 50-70% decrease in both PKC levels and insulin-stimulated 2-deoxyglucose uptake.
• The observed effects were specific to the antisense oligodeoxynucleotides targeting PKC mRNA.
• Insulin-stimulated diacylglycerol synthesis remained unaffected by the antisense treatment.
• Sense or nonsense oligodeoxynucleotides did not alter PKC levels or glucose uptake.

Conclusions:

• PKC-alpha and PKC-beta isozymes can be specifically downregulated in rat adipocytes using antisense oligodeoxynucleotides.
• Insulin-stimulated glucose transport in adipocytes is dependent on the activity of PKC.
• These findings highlight the critical role of specific PKC isozymes in insulin signaling and glucose metabolism.