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PubMed | Stanford University, Als Biopharma, Llc, St Jude Childrens Research Hospital and University of Arizona
Type: Journal Article | Journal: Human molecular genetics | Year: 2015

RNA dysregulation is a newly recognized disease mechanism in amyotrophic lateral sclerosis (ALS). Here we identify Drosophila fragile X mental retardation protein (dFMRP) as a robust genetic modifier of TDP-43-dependent toxicity in a Drosophila model of ALS. We find that dFMRP overexpression (dFMRP OE) mitigates TDP-43 dependent locomotor defects and reduced lifespan in Drosophila. TDP-43 and FMRP form a complex in flies and human cells. In motor neurons, TDP-43 expression increases the association of dFMRP with stress granules and colocalizes with polyA binding protein in a variant-dependent manner. Furthermore, dFMRP dosage modulates TDP-43 solubility and molecular mobility with overexpression of dFMRP resulting in a significant reduction of TDP-43 in the aggregate fraction. Polysome fractionation experiments indicate that dFMRP OE also relieves the translation inhibition of futsch mRNA, a TDP-43 target mRNA, which regulates neuromuscular synapse architecture. Restoration of futsch translation by dFMRP OE mitigates Futsch-dependent morphological phenotypes at the neuromuscular junction including synaptic size and presence of satellite boutons. Our data suggest a model whereby dFMRP is neuroprotective by remodeling TDP-43 containing RNA granules, reducing aggregation and restoring the translation of specific mRNAs in motor neurons.


Cassel J.A.,Als Biopharma, Llc | McDonnell M.E.,Fox Chase Chemical Diversity Center, Inc | Velvadapu V.,Fox Chase Chemical Diversity Center, Inc | Andrianov V.,Als Biopharma, Llc | Reitz A.B.,Als Biopharma, Llc
Biochimie | Year: 2012

Dysfunction of the heterogeneous ribonucleoprotein TAR DNA binding protein 43 (TDP-43) is associated with neurodegeneration in diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Here we examine the effects of a series of 4-aminoquinolines with affinity for TDP-43 upon caspase-7-induced cleavage of TDP-43 and TDP-43 cellular function. These compounds were mixed inhibitors of biotinylated TG6 binding to TDP-43, binding to both free and occupied TDP-43. Incubation of TDP-43 and caspase-7 in the presence of these compounds stimulated caspase-7 mediated cleavage of TDP-43. This effect was antagonized by the oligonucleotide TG12, prevented by denaturing TDP-43, and exhibited a similar relation of structure to function as for the displacement of bt-TG6 binding to TDP-43. In addition, the compounds did not affect caspase-7 enzyme activity. In human neuroglioma H4 cells, these compounds lowered levels of TDP-43 and increased TDP-43 C-terminal fragments via a caspase-dependent mechanism. Subsequent experiments demonstrated that this was due to induction of caspases 3 and 7 leading to increased PARP cleavage in H4 cells with similar rank order of the potency among the compounds tests for displacement of bt-TG6 binding. Exposure to these compounds also reduced HDAC-6, ATG-7, and increased LC3B, consistent with the effects of TDP-43 siRNA described by other investigators. These data suggest that such compounds may be useful biochemical probes to further understand both the normal and pathological functions of TDP-43, and its cleavage and metabolism promoted by caspases. © 2012 Published by Elsevier Masson SAS. All rights reserved.


Cassel J.A.,Als Biopharma, Llc | Reitz A.B.,Als Biopharma, Llc
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2013

Recently, it was reported that mutations in the ubiquitin-like protein ubiquilin-2 (UBQLN2) are associated with X-linked amyotrophic lateral sclerosis (ALS), and that both wild-type and mutant UBQLN2 can co-localize with aggregates of C-terminal fragments of TAR DNA binding protein (TDP-43). Here, we describe a high affinity interaction between UBQLN2 and TDP-43 and demonstrate that overexpression of both UBQLN2 and TDP-43 reduces levels of both exogenous and endogenous TDP-43 in human H4 cells. UBQLN2 bound with high affinity to both full length TDP-43 and a C-terminal TDP-43 fragment (261-414 aa) with K D values of 6.2 nM and 8.7 nM, respectively. Both DNA oligonucleotides and 4-aminoquinolines, which bind to TDP-43, also inhibited UBQLN2 binding to TDP-43 with similar rank order affinities compared to inhibition of oligonucleotide binding to TDP-43. Inhibitor characterization experiments demonstrated that the DNA oligonucleotides noncompetitively inhibited UBQLN2 binding to TDP-43, which is consistent with UBQLN2 binding to the C-terminal region of TDP-43. Interestingly, the 4-aminoquinolines were competitive inhibitors of UBQLN2 binding to TDP-43, suggesting that these compounds also bind to the C-terminal region of TDP-43. In support of the biochemical data, co-immunoprecipitation experiments demonstrated that both TDP-43 and UBQLN2 interact in human neuroglioma H4 cells. Finally, overexpression of UBQLN2 in the presence of overexpressed full length TDP-43 or C-terminal TDP-43 (170-414) dramatically lowered levels of both full length TDP-43 and C-terminal TDP-43 fragments (CTFs). Consequently, these data suggest that UBQLN2 enhances the clearance of TDP-43 and TDP-43 CTFs and therefore may play a role in the development of TDP-43 associated neurotoxicity. © 2013 Elsevier B.V.


Cassel J.A.,Als Biopharma, Llc | Ilyin S.,Als Biopharma, Llc | McDonnell M.E.,Fox Chase Chemical Diversity Center, Inc | Reitz A.B.,Als Biopharma, Llc
Bioorganic and Medicinal Chemistry | Year: 2012

Inhibitors of both heat shock proteins Hsp90 and Hsp70 have been identified in assays measuring luciferase refolding containing rabbit reticulocyte lysate or purified chaperone components. Here, we report the discovery of a series of phenoxy-N-arylacetamides that disrupt Hsp70-mediated luciferase refolding by binding to DnaJ, the bacterial homolog of human Hsp40. Inhibitor characterization experiments demonstrated negative cooperativity with respect to DnaJ and luciferase concentration, but varying the concentration of ATP had no effect on potency. Thermal shift analysis suggested a direct interaction with DnaJ, but not with Hsp70. These compounds may be useful tools for studying DnaJ/Hsp40 in various cellular processes. © 2012 Elsevier Ltd. All rights reserved.


Cassel J.A.,Als Biopharma, Llc | Blass B.E.,Fox Chase Chemical Diversity Center, Inc | Reitz A.B.,Als Biopharma, Llc | Pawlyk A.C.,Als Biopharma, Llc
Journal of Biomolecular Screening | Year: 2010

TAR DNA binding protein 43 (TDP-43) is a nucleic acid binding protein that is associated with the pathology of cystic fibrosis and neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar dementia. We have developed a robust, quantitative, nonradiometric high-throughput assay measuring oligonucleotide binding to TDP-43 using AlphaScreen® technology. Biotinylated single-stranded TAR DNA (bt-TAR-32) and 6 TG repeats (bt-TG6) bound with high affinity to TDP-43, with KD values of 0.75 nM and 0.63 nM, respectively. Both oligonucleotides exhibited slow dissociation rates, with half-lives of 750 min for bt-TAR-32 and 150 min for bt-TG6. The affinities of unlabeled oligonucleotides, as determined by displacement of either bt-TAR-32 or bt-TG6, were consistent with previous reports of nucleic acid interactions with TDP-43, where increasing TG or UG repeats yield greater affinity. A diversity library of 7360 compounds was screened for inhibition of TDP-43 binding to bt-TAR-32, and a series of compounds was discovered with nascent SAR and IC50 values ranging from 100 nM to 10 μM. These compounds may prove to be useful biochemical tools to elucidate the function of TDP-43 and may lead to novel therapeutics for indications where the TDP-43 nucleic acid interaction is causal to the associated pathology. (Journal of Biomolecular Screening 2010;1099-1106) © 2010 Society for Laboratory Automation and Screening.


Pawlyk A.C.,Als Biopharma, Llc | Cassel J.A.,Als Biopharma, Llc | Reitz A.B.,Als Biopharma, Llc
Current Pharmaceutical Design | Year: 2010

Amyotrophic lateral sclerosis (ALS) is a debilitating and ultimately fatal indication that is the most prevalent adult-onset motoneuron disorder. ALS imparts tremendous suffering upon patients and caregivers alike. Exciting new insight has been obtained as to the etiology and initiation of the disease during the past decade, particularly affecting the larger, sporadic patient population. An important new discovery is the involvement of the TAR DNA binding protein (TDP-43) based upon genetic evidence and the presence of the cytosolic ubiquitinylated TDP-43 aggregates found during post-mortem analysis of damaged motoneuron in the spinal cord of ALS patients. Superoxide dismutase (SOD1) continues to be of interest for the ~20% of the familial ALS patients who have the inherited form of the disease (~15% of the total), but SOD1 does not appear to be as relevant as was once imagined for the sporadic patient population. We can now target specific biochemical pathways and deficits via traditional drug discovery efforts and may thus be able to achieve more effective therapeutic relief for patients who suffer from this disease. In this review we present a comprehensive discussion of current molecular targets and pathways that are of interest to small molecule drug discovery efforts for the treatment of ALS. © 2010 Bentham Science Publishers Ltd.


The present invention includes methods of generating derivatives of a protein, as well as methods of treating a subject with the derivatized proteins. More particularly, the present invention includes methods of generating derivatives of HSP 70 proteins and methods of treating a subject with the derivatized HSP 70 proteins.


Grant
Agency: Department of Health and Human Services | Branch: | Program: STTR | Phase: Phase I | Award Amount: 286.28K | Year: 2013

DESCRIPTION: We identified the Myrica cerifera (Southern Bayberry) extract using a systematic screen as a potent reducer of the structural protein tau, which accumulates in a group of diseases called the tauopathies . The most prevalent tauopathy is Alzheimer's disease, for which there is renewed interest in the identification of tau- based therapeutic approaches to treat this devastating disease; however mutations in the tau gene are the unequivocal cause of some cases of frontotemporal dementia (FTD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Few therapeutic strategies have targeted the tau protein, despite it being seen as the key factor contributing to neuronal loss in these tauopathies. In fact, depleting tau has shownpromise in ameliorating the cognitive impairment observed in mouse models in which either wild-type or mutant tau is overexpressed. Organic extraction, bioactivity-driven fractionation and nuclear magnetic resonance spectroscopy identified the cyclic diarylheptanoid myricanol as one of the main active components from Bayberry involved in lowering tau levels. A previously-uncharacterized enantiomer of myricanol [(S)-myricanol] was the predominant species produced in Myrica cerifera, and found to be primarilyresponsible for the tau lowering activity. (S)-Myricanol has no violations of the Lipinsk guidelines and, as a natural product, may be subject to active transport processes which may be useful for the oral route of administration. (S)-Myricanol representsa tractable drug candidate for both on its own as a potential therapeutic and as a novel scaffold for further structure activity relationship development. Thus, with the need for emergent anti-tau drugs to treat AD and related tauopathies we will: 1) improve the isolation of (+)-S-myricanol from Myrica cerifera, 2) develop a high-yielding and stereoselective route for the production of synthetic (S)-myricanol which will also be amenable to the preparation of novel derivatives based upon guidance from our preliminary SAR development, and 3) determine the efficacy and conduct eADME (early absorption, distribution, metabolism, and excretion) studies on (S)-myricanol and a limited subset of derivatives. The eADME studies will include metabolism in mouse and human liver microsomes, human plasma protein binding, water solubility testing, broad receptor and ion channel profiling including hERG, and initial pharmacokinetic testing in rats. We would seek to direct our program to identify agents that would be suitablefor once-daily, oral administration for the treatment of tauopathies, to increase patient compliance and penetration. We will also continue studies to characterize the mechanism of action of (S)-myricanol using a multipronged approach, taking advantage oftool and reagents that we have uniquely prepared to investigate tau biochemistry. Ultimately these studies could provide a novel series of natural-product derived tau-lowering agents as probes for pre-clinical evaluation in animal models characteristic ofthe tauopathies, and provide in vivo proof of concept validation to serve as a springboard into Phase II of the STTR program for eventual preclinical development and commercialization. PUBLIC HEALTH RELEVANCE PUBLIC HEALTH RELEVANCE: The structural protein tau accumulates in more than 15 neurodegenerative diseases, collectively termed tauopathies , with the most common being Alzheimer's disease. Despite this fact, only one drug currently in clinical trials targets the tau protein specifically.Here, using newly identified chemical tools based our discovery of the unexpected tau lowering properties of the natural product (S)-myricanol we will explore whether the tau protein can be cleared from the brain in vivo and seek to identify drug candidates that are beneficial for the treatment of tauopathies including Alzheimer's disease.


PubMed | Als Biopharma, Llc
Type: Journal Article | Journal: Bioorganic & medicinal chemistry | Year: 2012

Inhibitors of both heat shock proteins Hsp90 and Hsp70 have been identified in assays measuring luciferase refolding containing rabbit reticulocyte lysate or purified chaperone components. Here, we report the discovery of a series of phenoxy-N-arylacetamides that disrupt Hsp70-mediated luciferase refolding by binding to DnaJ, the bacterial homolog of human Hsp40. Inhibitor characterization experiments demonstrated negative cooperativity with respect to DnaJ and luciferase concentration, but varying the concentration of ATP had no effect on potency. Thermal shift analysis suggested a direct interaction with DnaJ, but not with Hsp70. These compounds may be useful tools for studying DnaJ/Hsp40 in various cellular processes.


PubMed | Als Biopharma, Llc
Type: Journal Article | Journal: Biochimie | Year: 2012

Dysfunction of the heterogeneous ribonucleoprotein TAR DNA binding protein 43 (TDP-43) is associated with neurodegeneration in diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Here we examine the effects of a series of 4-aminoquinolines with affinity for TDP-43 upon caspase-7-induced cleavage of TDP-43 and TDP-43 cellular function. These compounds were mixed inhibitors of biotinylated TG6 binding to TDP-43, binding to both free and occupied TDP-43. Incubation of TDP-43 and caspase-7 in the presence of these compounds stimulated caspase-7 mediated cleavage of TDP-43. This effect was antagonized by the oligonucleotide TG12, prevented by denaturing TDP-43, and exhibited a similar relation of structure to function as for the displacement of bt-TG6 binding to TDP-43. In addition, the compounds did not affect caspase-7 enzyme activity. In human neuroglioma H4 cells, these compounds lowered levels of TDP-43 and increased TDP-43 C-terminal fragments via a caspase-dependent mechanism. Subsequent experiments demonstrated that this was due to induction of caspases 3 and 7 leading to increased PARP cleavage in H4 cells with similar rank order of the potency among the compounds tests for displacement of bt-TG6 binding. Exposure to these compounds also reduced HDAC-6, ATG-7, and increased LC3B, consistent with the effects of TDP-43 siRNA described by other investigators. These data suggest that such compounds may be useful biochemical probes to further understand both the normal and pathological functions of TDP-43, and its cleavage and metabolism promoted by caspases.

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