neurodegenerative disease – Science at Brandeis

Mugdha Deshpande named Blazeman Postdoctoral Fellow

Assistant Professor of Biology Avital Rodal has received a grant from the Blazeman Foundation to study the traffic of growth signals in neurons in the animal models of ALS (Amyotrophic Lateral Sclerosis). ALS, commonly known as ‘Lou Gehrig’s disease’, is a neurodegenerative disease that causes the loss of motor neurons. The Blazeman Foundation is a non-profit organization working to increase the awareness about this terminal disease and to support research towards finding treatments. Funding to the Rodal lab has enabled creation of the Blazeman Foundation Postdoctoral Fellowship for ALS Research, awarded to Mugdha Deshpande, Ph.D., who will use live imaging to examine and manipulate membrane traffic in fruit fly models of ALS, and who will also work with Dr. Suzanne Paradis to translate her findings to mammalian ALS models.

You can read more at BrandeisNOW.

Rodal to Receive NIH New Innovator Award

The NIH recently announced that Assistant Professor of Biology Avital Rodal will be a recipient of the 2012 NIH Directors New Innovator Award. The award allows new, exceptionally creative and ambitious investigators to begin high impact research projects. Granted to early stage investigators, candidates are eligible for the award for up to ten years after the completion of their PhD or MD. The award emphasizes bold, new approaches, which have the potential to spur large scientific steps forward. This year’s award was made to fifty-one researchers, and provides each with 1.5 million dollars of direct research funding over five years.

The Rodal lab studies the mechanisms of membrane deformation and endosomal traffic in neurons as they relate to growth signaling and disease. Membrane deformation by a core set of conserved protein complexes leads to the creation of tubules and vesicles from the plasma membrane and internal compartments. Endocytic vesicles contain, among other cargoes, activated growth factors and receptors, which traffic to the neuronal cell body to drive transcriptional responses (see movie). These growth cues somehow coordinate with neuronal activity to dramatically alter the morphology of the neuron, and disruptions to both endocytic pathways and neuronal activity have been implicated in neurodegenerative diseases such as amyotrophic lateral sclerosis and Alzheimer’s disease.

Dr. Rodal hopes to determine how neuronal activity affects the in vivo function and biochemical composition of the membrane trafficking machinery, by examining the transport of fluorescently labeled growth factor receptors in chronically or acutely activated neurons at the Drosophila neuromuscular junction (NMJ). Her group will combine these live imaging studies with a proteomic analysis of endocytic machinery purified from hyper-activated and under-activated neurons. By investigating the interplay between neuronal activity, membrane deformation, and receptor localization in live animal NMJs, she hopes to gain a better understanding of the strategies that healthy neurons employ to regulate membrane trafficking events, and provide new insight into specific points of failure in neurodegenerative disease.

see also story at Brandeis NOW

What a failed drug does (and is there hope for latrepirdine?)

Latrepirdine (Dimebon) was initially used as an antihistamine drug in Russia. It was later found to be neuroprotective, and entered phase II clinical trials in the US for both Alzheimer’s disease and Huntington’s disease. However, Dimebon failed in a US-based phase II replication trial of a prior successful Russian phase II trial of mild-to-moderate AD. Given the initial promise of the drug and split results, as well as the lack of treatments for neurodegenerative diseases, there in is significant interest in understanding the underlying molecular mechanism(s) for the drug’s effects.

In a paper appearing this week in Molecular Psychiatry, Brandeis researchers in the Petsko-Ringe lab, including postdoc Shulin Ju and undergraduate Jessica Liken ’11, used yeast models of neurodegenerative disease associated proteins to show that Dimebon specifically protects yeast from the cytotoxiciy of α-synuclein, a protein involved in Parkinson’s disease. They further showed that protection is mediated through its up-regulation of autophagy pathway. In collaboration with Sam Gandy‘s group at Mount Sinai School of Medicine, these findings were further confirmed and validated in neuronal cell and animal models.

Given these observations, disparities in the contribution of α-synuclein to the neuropathology between the Russian and US Dimebon studies might also explain, at least in part, the inconsistency of the cognitive benefit in the two trials. If this speculation is correct, then it may be interesting to test for benefits of Dimebon in treating synucleinopathies such as Parkinson’s disease, Lewy body dementia, REM sleep disorder and/or multiple system atrophy.

Steele JW (*), Ju S(*), Lachenmayer ML(*), Liken J, Stock A, Kim SH, Delgado LM, Alfaro IE, Bernales S, Verdile G, Bharadwaj P, Gupta V, Barr R, Friss A, Dolios G, Wang R, Ringe D, Protter AA, Martins RN, Ehrlich ME, Yue Z, Petsko GA, Gandy S. Latrepirdine stimulates autophagy and reduces accumulation of alpha-synuclein in cells and in mouse brain. Molecular psychiatry. 2012.

Steele JW(*), Lachenmayer ML(*), Ju S, Stock A, Liken J, Kim SH, Delgado LM, Alfaro IE, Bernales S, Verdile G, Bharadwaj P, Gupta V, Barr R, Friss A, Dolios G, Wang R, Ringe D, Fraser P, Westaway D, St George-Hyslop PH, Szabo P, Relkin NR, Buxbaum JD, Glabe CG, Protter AA, Martins RN, Ehrlich ME, Petsko GA, Yue Z, Gandy S. Latrepirdine improves cognition and arrests progression of neuropathology in an Alzheimer’s mouse model. Molecular psychiatry. 2012.

Brandeis Café Science Opens Tonight

Brandeis scientists have started a Science Cafe, to discuss contemporary research in the life sciences, physics, chemistry and related fields. The Cafe provides a way for non-scientists at Brandeis, and for residents of Waltham and surrounding communities, to learn about science from Brandeis’ accomplished scientists. It is also a way for life scientists to learn something about physics and vice versa!

The Cafe will be held 6-7 PM the first Monday of every month at the Elephant Walk in Waltham at 663 Main St (with parking nearby at the Common St garage). The first speaker is Greg Petsko (Biochemistry) who will speak about “Drugs for Neurologic Disorders” on April 2 (tonight). $10 admission gets you a drink and a talk.

See story at boston.com.

What is α-synuclein when it’s not aggregated?

In a recent paper in PNAS, co-lead authors Wei Wang (Indiana U. School of Medicine) and Iva Perovic (Chemistry Ph. D. program, Brandeis), together with researchers from Brandeis, Indiana, Scripps, NIH, Washington State, and Harvard, investigated the structure of the abundant small neuronal protein α-synuclein. α-Synuclein has been strongly associated with the disease process in Parkinson disease, both from histology (found in aggregates in Lewy bodies associated with disease) and from genetics (mutations in the gene associated with a rare familial form of Parkinson disease). The structure and function of α-synuclein is not well understood. It is an abundant neuronal protein, and appears to bind to lipids, vesicles, and plasma membrane. Heterologously expressed α-synuclein is often observed to be unfolded, and the biochemical role of the protein is still unidentified.

In this new study, α-synuclein was expressed as a GST fusion protein in E. coli and proteolytically cleaved to form α-synuclein with a 10 amino acid N-terminal extension. This protein was shown to form a stable tetrameter with alpha-helical content in the absence of lipids, using a combination of many techniques, including NMR spectroscopy, electron microscopy, circular dichroism and mass spectroscopy of cross-linked products. The authors combined this information to propose a model for the structure of native α-synuclein when it is not aggregated that is a tetramer based on amphipathic central helices.

Researchers in the Pochapsky, Petsko-Ringe and Agar labs at Brandeis participated in the study. Future work is aimed at understanding the function of this tetrameric form of the protein, with the hope of developing techniques to stabilize it and determine its function. For more information and interview with the authors, see the story at BrandeisNOW.

Yeast genetics and familial ALS

In a recent paper in PLoS Biology, “A Yeast Model of FUS/TLS-Dependent Cytotoxicity“, Brandeis postdoc Shulin Ju and coworkers applied yeast genetics to examine the function of the human protein FUS/TLS. The gene for FUS/TLS is mutated in 5-10$ of cases of Familial ALS. The yeast model expressing the mutant protein recapitulates many important features of the pathology.

A particular feature of interest is that FUS/TLS form cytoplasmic inclusions of this protein which is normally localized to the nucleus. Over-expression of a number of yeast proteins rescues the cells from the toxic effect without removing the inclusions. The results are suggested to implicate RNA processing or RNA quality control in the mechanism of toxicity, which I find really interesting in light of the talk Susan Lindquist (an author on this paper) gave at Brandeis about yeast prions and regulatory proteins earlier this month.

Other authors on the paper include Brandeis professors Dagmar Ringe and Gregory Petsko, and Brandeis alumni Dan Tardiff (PhD, Mol. Cell. Biol., ’07), currently a postdoc in the Lindquist lab at the Whitehead Institute, and Daryl Bosco (PhD, Bioorganic Chem, ’03), currently on the faculty at U. Mass. Medical School.

For more information, please see the paper itself or the longer article about the research on Brandeis NOW.