let-7-repressesed Shc translation delays replicative senescence

Area of Science:

• Molecular Biology
• Genetics
• Aging Research

Background:

• The p66Shc adaptor protein influences mammalian lifespan, but its regulatory mechanisms remain elusive.
• Understanding the regulation of Shc proteins is crucial for deciphering lifespan control.

Purpose of the Study:

• To elucidate the post-transcriptional regulation of Shc protein expression.
• To investigate the role of microRNA let-7a in controlling Shc levels and cellular senescence.

Main Methods:

• Analysis of microRNA and protein expression levels.
• Identification and mutation of let-7a interaction elements in Shc mRNA.
• Assessment of cellular senescence in human diploid fibroblasts (HDFs).

Main Results:

• MicroRNA let-7a inversely correlates with Shc protein levels (p66Shc, p52Shc, p46Shc) without affecting Shc mRNA.
• Identified 'seedless' let-7a interaction sites in the Shc mRNA coding region essential for regulation.
• let-7a-mediated repression of Shc expression delays senescence in HDFs.

Conclusions:

• let-7a directly regulates Shc protein expression at the post-transcriptional level.
• The let-7a-Shc axis is a key determinant of cellular replicative lifespan and senescence.
• Findings establish a link between microRNA abundance, p66Shc, and aging processes.