Neuronal apoptosis induced by endoplasmic reticulum stress

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Apoptosis is a critical cellular process in the nervous system, vital for development and implicated in neurodegenerative diseases.
• Endoplasmic reticulum (ER) stress, caused by protein misfolding or transport inhibition, can induce apoptosis.

Purpose of the Study:

• To investigate the downstream molecular events of apoptosis in differentiated PC 12 cells subjected to ER stress.
• To elucidate the specific pathways involved in ER stress-induced neuronal cell death.

Main Methods:

• PC 12 cells were treated with brefeldin A to induce ER stress, inhibiting ER to Golgi protein transport.
• Key molecular markers of apoptosis, including NF-kappaB, I-kappaB, GRP78, and caspase-12 activation, were monitored over time.
• Nuclear fragmentation was assessed as a hallmark of late-stage apoptosis.

Main Results:

• Activation of NF-kappaB and degradation of I-kappaB occurred within 2 hours of brefeldin A treatment.
• GRP78 protein levels were upregulated in response to ER stress.
• Caspase-12 activation and nuclear fragmentation were observed around 24 hours post-treatment, indicating late-stage apoptosis.

Conclusions:

• ER stress induces neuronal apoptosis through a pathway involving NF-kappaB activation.
• Caspase-12 plays a role in the later stages of ER stress-induced neuronal cell death.
• These findings highlight a NF-kappaB and caspase-dependent mechanism underlying ER stress-mediated apoptosis in neurons.