Pirh2 modulates the mitochondrial function and cytochrome c-mediated neuronal death during Alzheimer's disease

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• DNA damage is a critical factor in Alzheimer's disease (AD) pathogenesis.
• Pirh2, an E3 ubiquitin ligase, regulates DNA damage responses.
• The specific role of Pirh2 in AD pathology remains largely unexplored.

Purpose of the Study:

• To investigate the role of Pirh2 in a rodent model of Alzheimer's disease.
• To elucidate the molecular mechanisms by which Pirh2 influences AD-related pathology.
• To assess the therapeutic potential of targeting Pirh2 in AD.

Main Methods:

• Induction of AD model using streptozotocin and oligomeric amyloid-beta (Aβ1-42).
• Assessment of Pirh2 protein levels and its modulation via transient silencing.
• Biochemical assays to evaluate oxidative stress, mitochondrial function (membrane potential, Complex-I activity, ATP levels), and apoptosis markers.
• Mass spectrometry (MALDI-TOF/TOF), co-immunoprecipitation, and ubiquitylation assays to confirm protein interactions and ubiquitination.
• Analysis of nuclear translocation of apoptosis-inducing factors and DNA damage.

Main Results:

• Pirh2 protein levels were elevated in the AD model.
• Pirh2 silencing significantly reduced AD markers: p-Tau, β-amyloid, acetylcholinesterase activity, and neuronal death.
• Silencing Pirh2 attenuated oxidative stress, improved mitochondrial function, and inhibited apoptosis.
• Pirh2 directly interacts with cytochrome c, promoting its ubiquitylation and subsequent translocation.
• Pirh2 silencing prevented the nuclear translocation of endonuclease G and other apoptosis-inducing factors, reducing DNA damage.

Conclusions:

• Pirh2 plays a significant role in Alzheimer's disease pathogenesis.
• Pirh2 contributes to AD by disrupting mitochondrial function, promoting apoptosis, and inducing DNA damage.
• Targeting Pirh2 presents a promising therapeutic strategy for Alzheimer's disease.