Insights Into the Role of Heat Shock Protein 27 in the Development of Neurodegeneration

Mechanistic insights into heat shock protein 27, a potential therapeutic target for cardiovascular diseases

Heat shock protein 27 (HSP27) is a small chaperone protein that is overexpressed in a variety of cellular stress states. It is involved in regulating proteostasis and protecting cells from multiple sources of stress injury by stabilizing protein conformation and promoting the refolding of misfolded proteins. Previous studies have confirmed that HSP27 is involved in the development of cardiovascular diseases and plays an important regulatory role in this process. Herein, we comprehensively and systematically summarize the involvement of HSP27 and its phosphorylated form in pathophysiological processes, including oxidative stress, inflammatory responses, and apoptosis, and further explore the potential mechanisms and possible roles of HSP27 in the diagnosis and treatment of cardiovascular diseases. Targeting HSP27 is a promising future strategy for the treatment of cardiovascular diseases.

A Charcot-Marie-Tooth-Causing Mutation in HSPB1 Decreases Cell Adaptation to Repeated Stress by Disrupting Autophagic Clearance of Misfolded Proteins

Charcot-Marie-Tooth (CMT) disease is the most common inherited neurodegenerative disorder with selective degeneration of peripheral nerves. Despite advances in identifying CMT-causing genes, the underlying molecular mechanism, particularly of selective degeneration of peripheral neurons remains to be elucidated. Since peripheral neurons are sensitive to multiple stresses, we hypothesized that daily repeated stress might be an essential contributor to the selective degeneration of peripheral neurons induced by CMT-causing mutations. Here, we mainly focused on the biological effects of the dominant missense mutation (S135F) in the 27-kDa small heat-shock protein HSPB1 under repeated heat shock. HSPB1S135F presented hyperactive binding to both α-tubulin and acetylated α-tubulin during repeated heat shock when compared with the wild type. The aberrant interactions with tubulin prevented microtubule-based transport of heat shock-induced misfolded proteins for the formation of perinuclear aggresomes. Furthermore, the transport of autophagosomes along microtubules was also blocked. These results indicate that the autophagy pathway was disrupted, leading to an accumulation of ubiquitinated protein aggregates and a significant decrease in cell adaptation to repeated stress. Our findings provide novel insights into the molecular mechanisms of HSPB1S135F-induced selective degeneration of peripheral neurons and perspectives for targeting autophagy as a promising therapeutic strategy for CMT neuropathy.