蛋白修饰也许可解释帕金森氏病神经退行性病变的解剖特异性
WESTPORT, CT (Reuters Health) - Researchers have identified an unusual protein modification that may explain the loss of dopaminergic neurons seen in Parkinson's disease (PD), according to a report published in the November 9th issue of Science.
In the brains of patients with PD, the substantia nigra is depleted of dopaminergic neurons, and an accumulation of fibrillar protein deposits, known as Lewy bodies, occurs. The major component of the deposited fibrils is alpha-synuclein.
, 百拇医药
Dr. Peter T. Lansbury and colleagues from the Harvard Medical School in Cambridge, Massachusetts screened a compound library for molecules that inhibited the formation of alpha-synuclein fibrils.
In PD brains, alpha-synuclein is known to exist in two forms: a normal form, abundant throughout life, and a fibrillar form, seen at autopsy. However, in previous studies, the researchers identified a third form, known as the protofibril form, which appeared to be an intermediate between the other two. Based on their work, the researchers believed that the protofibril was the neurotoxic form.
, http://www.100md.com
Initially, the investigators were interested in compounds that might inhibit protofibril formation. In the course of their studies, however, they uncovered 15 compounds that inhibited the protofibril-to-fibril conversion. Interestingly, all but one of these compounds were catecholamines related to dopamine.
Further analysis revealed that dopamine itself could inhibit fibril formation and lead to accumulation of protofibrils. The inhibitory effect depended on dopamine oxidation with subsequent modification of alpha-synuclein to form an adduct. Therefore, if dopamine is capable of producing the potentially toxic protofibrils it could explain why dopaminergic neurons are destroyed with PD.
, 百拇医药
"The current findings raise the often-asked question of whether dopamine replacement therapies have any effect on the underlying disease course," Dr. Lansbury told Reuters Health. "Whatever the effect, our results suggest that dopamine oxidation is bad," he added.
"The dopamine-alpha-synuclein adduct we identified could be a potential marker for PD neurodegeneration," Dr. Lansbury noted. "Ultimately, we may be able to detect PD before it becomes clinically apparent," he said.
"In terms of existing therapies for PD, they are all symptomatically based," Dr. Lansbury stated. In contrast "the current findings have implications for new strategies designed to get at the underlying cause," he said.
Science 2001;294:1346-1349.
-Westport Newsroom 203 319 2700, 百拇医药
In the brains of patients with PD, the substantia nigra is depleted of dopaminergic neurons, and an accumulation of fibrillar protein deposits, known as Lewy bodies, occurs. The major component of the deposited fibrils is alpha-synuclein.
, 百拇医药
Dr. Peter T. Lansbury and colleagues from the Harvard Medical School in Cambridge, Massachusetts screened a compound library for molecules that inhibited the formation of alpha-synuclein fibrils.
In PD brains, alpha-synuclein is known to exist in two forms: a normal form, abundant throughout life, and a fibrillar form, seen at autopsy. However, in previous studies, the researchers identified a third form, known as the protofibril form, which appeared to be an intermediate between the other two. Based on their work, the researchers believed that the protofibril was the neurotoxic form.
, http://www.100md.com
Initially, the investigators were interested in compounds that might inhibit protofibril formation. In the course of their studies, however, they uncovered 15 compounds that inhibited the protofibril-to-fibril conversion. Interestingly, all but one of these compounds were catecholamines related to dopamine.
Further analysis revealed that dopamine itself could inhibit fibril formation and lead to accumulation of protofibrils. The inhibitory effect depended on dopamine oxidation with subsequent modification of alpha-synuclein to form an adduct. Therefore, if dopamine is capable of producing the potentially toxic protofibrils it could explain why dopaminergic neurons are destroyed with PD.
, 百拇医药
"The current findings raise the often-asked question of whether dopamine replacement therapies have any effect on the underlying disease course," Dr. Lansbury told Reuters Health. "Whatever the effect, our results suggest that dopamine oxidation is bad," he added.
"The dopamine-alpha-synuclein adduct we identified could be a potential marker for PD neurodegeneration," Dr. Lansbury noted. "Ultimately, we may be able to detect PD before it becomes clinically apparent," he said.
"In terms of existing therapies for PD, they are all symptomatically based," Dr. Lansbury stated. In contrast "the current findings have implications for new strategies designed to get at the underlying cause," he said.
Science 2001;294:1346-1349.
-Westport Newsroom 203 319 2700, 百拇医药