性吧导航

A fruit fly, like the kind that recovered their learning and memory capabilities as larvae in this study.

Researchers from 性吧导航 reversed symptoms of Alzheimer鈥檚 disease in fruit flies by restoring the balance between two epigenetic enzymes that regulate gene expression, a study shows.

Early in the progression of Alzheimer鈥檚 disease, cognitive impairment (such as difficulties with learning and memory) may be tied to the presence of elevated levels of the HDAC2 enzyme. HDAC2 helps control how genes linked to learning and memory are expressed. It appears that when HDAC2 overwhelms the enzyme it is paired with, which is called Tip60 HAT, it represses genes and leads to problems with neuroplasticity 鈥� the brain鈥檚 ability to adapt to new stimuli or recall reactions to stimuli it already encountered.

But a research team led by Priyalakshmi Panikker, a PhD student, and  an associate professor, both in Drexel鈥檚 College of Arts and Sciences, performed tests in flies and found that if they added extra Tip60 HAT in the brain of flies that displayed symptoms close to Alzheimer鈥檚 disease, the balance between the enzymes could be successfully restored.  When that balance came back, behaviors the team had taught the flies were able to be learned again and remembered.

鈥淥ur findings strongly support the concept of exploring the efficacy of specific Tip60 HAT activators, as well as identifying and manipulating additionally misregulated Tip60 target genes,鈥� Elefant said.

Elefant, Panikker and their team 鈥� whose findings were published in the  鈥� looked at how Alzheimer鈥檚 disease affected flies early in their development, during their larval stages, to catch what might happen in Alzheimer鈥檚 well before the tell-tale symptoms arise.

鈥淢any researchers that study Alzheimer鈥檚 disease utilize human post-mortem samples, and thus, they are not looking at what is happening during the early progression of neurodegeneration, including whether we can correctwhat is happening during these early stages ,鈥� Elefant said.

For the study, flies were taught to associate a certain odor with sucrose 鈥� table sugar, which flies eat and is a positive reinforcement.  After being exposed to the scent paired with sugar, the flies learned to move towards the scent even without the sugar present. 

Flies that modeled Alzheimer鈥檚 disease showed no difference in their reaction to the smell they had earlier been condition to.  This showed that their ability to learn and remember this association was negatively affected.

But once Tip60 HAT was introduced in the brain to correct the identified Tip60 HAT/HDAC2 imbalance, these flies showed a reaction time comparable to the ones without the Alzheimer鈥檚 type of condition. This indicated that they recovered their ability to learn and remember after the epigenetic balance was reintroduced.

Moreover, when researchers identified a collection of genes related to brain function that had been repressed in the flies 鈥� due to elevated HDAC2 鈥� an introduction of increased Tip60 HAT levels in the brain restored regular function in 9 of the 11 genes tested.

The results Panikker and Elefant found were encouraging. More testing is needed, but Elefant鈥檚 goal is to find new avenues for gene therapy.

鈥淲hen people age, they have a loss of memory but it鈥檚 not because there are mutations in their genes,鈥� Elefant said. 鈥淚t鈥檚 the way they鈥檙e packaged. They鈥檙e distorted. And we鈥檙e seeing non-invasive ways we might be able to prevent that early on.鈥� 

Those interested in reading the full study, 鈥淩estoring Tip60 HAT/HDAC2 balance in the neurodegenerative brain relieves epigenetic transcriptional repression and reinstates cognition,鈥� can .