Alzheimer's disease (AD) is by far the most common neurodegenerative disorder whose incidence exponentially increases in the aging population. Although signs and symptoms of clinically manifest AD are well defined, no effective therapy is yet available able to regress it yet and the pathogenesis is still matter of discussion. One of the most accredited theory posits the crucial role in AD pathogenic pathways of amyloid beta peptide (A?), especially when organized as oligomers. These small A? aggregates are neurotoxic both in vitro and in vivo. In addition, A? oligomers have been shown to induce alterations of mitochondria and disrupt long term potentiation (LTP) in amyloid precursor protein (APP) overexpressing transgenic mice that recapitulate salient AD pathology. Despite this established experimental knowledge, potential mechanisms able to inhibit this cascade remain elusive. Compelling evidence by us and others indicates a mechanism of interaction between the A? peptide and the Hsp60, a mitochondrial chaperonin that may be involved in preventing mitochondrial deficits associated with AD pathology. Indeed, post mortem studies on AD brains revealed a significant increase of oxidative stress when compared to age-matched control subjects. Furthermore, there are combined and multiple variations in chaperones and proteasome activities, responsible for the accumulation of neurotoxic species in senescent central nervous system especially when AD occurs. While the involvement of Hsp60 in mitochondrial oxidative metabolism caused by A? is well documented, there are few studies describing the biophysical mechanism of direct interaction between these two proteins. Here, we investigate the inhibitory effect of Hsp60 on the A?1-40 aggregation by the Thioflavine T assay and Circular Dichroism analysis. Furthermore, Isothermal Titration Calorimetry experiments are conducted in order to characterize the Hsp60/ A?1-40 binding parameters. Our preliminary results show a direct interaction between A?1-40 and Hsp60 responsible for a significant slowdown in the aggregation kinetic and perturbation of the A? peptide secondary structure. Overall, these results suggest Hsp60 as a new target for the development of innovative therapies for AD centered on prevention of A?-driven mitochondrial damage.
The inhibitory effect of Hsp60 on amyloid beta aggregation: A biophysical study
C MARINO;D SPIGOLON;S VILASI;R PASSANTINO;M R MANGIONE;D BULONE;P SAN BIAGIO
2014
Abstract
Alzheimer's disease (AD) is by far the most common neurodegenerative disorder whose incidence exponentially increases in the aging population. Although signs and symptoms of clinically manifest AD are well defined, no effective therapy is yet available able to regress it yet and the pathogenesis is still matter of discussion. One of the most accredited theory posits the crucial role in AD pathogenic pathways of amyloid beta peptide (A?), especially when organized as oligomers. These small A? aggregates are neurotoxic both in vitro and in vivo. In addition, A? oligomers have been shown to induce alterations of mitochondria and disrupt long term potentiation (LTP) in amyloid precursor protein (APP) overexpressing transgenic mice that recapitulate salient AD pathology. Despite this established experimental knowledge, potential mechanisms able to inhibit this cascade remain elusive. Compelling evidence by us and others indicates a mechanism of interaction between the A? peptide and the Hsp60, a mitochondrial chaperonin that may be involved in preventing mitochondrial deficits associated with AD pathology. Indeed, post mortem studies on AD brains revealed a significant increase of oxidative stress when compared to age-matched control subjects. Furthermore, there are combined and multiple variations in chaperones and proteasome activities, responsible for the accumulation of neurotoxic species in senescent central nervous system especially when AD occurs. While the involvement of Hsp60 in mitochondrial oxidative metabolism caused by A? is well documented, there are few studies describing the biophysical mechanism of direct interaction between these two proteins. Here, we investigate the inhibitory effect of Hsp60 on the A?1-40 aggregation by the Thioflavine T assay and Circular Dichroism analysis. Furthermore, Isothermal Titration Calorimetry experiments are conducted in order to characterize the Hsp60/ A?1-40 binding parameters. Our preliminary results show a direct interaction between A?1-40 and Hsp60 responsible for a significant slowdown in the aggregation kinetic and perturbation of the A? peptide secondary structure. Overall, these results suggest Hsp60 as a new target for the development of innovative therapies for AD centered on prevention of A?-driven mitochondrial damage.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
