Puneet Opal, MD, PhD - US grants

Palliative Care (PC) consultation intervention services are increasing dramatically in the acute care hospital setting with minimal knowledge of all that this intervention entails. The overall purpose of this 4- year ethnographic study is to develop a thick description of the multiple facets that a palliative care consultation service entails, how they work, their barriers and facilitators, and their specific outcomes in the context of the acute care hospital culture. There is strong evidence that care providers inadequately manage pain and other symptoms such as dyspnea and fatigue in the acute care setting, especially for patients near the end of life. There are difficulties in communication, treatment decision-making, and, when necessary, end of life planning with hospitalized persons with serious and/or life threatening illness. The number of adults living longer and living with serious chronic illness requiring periodic hospitalization is growing rapidly. In recognition of these and other concerns, hospitals are developing multidisciplinary palliative care programs. However, the integration of PC into acute care settings is challenging because palliative and acute care specialties arise from two separate cultures, the former from a hospice culture and the latter from a curative culture. The specific aims include: 1) To describe and analyze the intersection of palliative care and hospital cultures as well as the facilitators and barriers associated with PC consultation in the hospital setting; 2) To describe the patterns of aggressive and palliative care treatment goals and how they change over time in both sequential and concurrent PC consultation; 3) To examine the experiences and culture of PC consultation from the perspectives of patients, families, the referring and PC consultation providers; and 4) To describe the outcomes of PC consultation from the perspectives of patients, families, and the referring and PC consultation care providers. This timely study will help fill a critical gap in the scientific knowledge by helping researchers and providers to better understand the evolving culture in which PC is delivered which will in turn, allow for the development of effective interventions to improve PC in the acute care setting.

[unreadable] DESCRIPTION (provided by applicant): Spinocerebellar ataxia type 1 (SCA1) is an inherited disease that causes progressive instability of gait or ataxia. This disease is caused by an expansion of a stretch of glutamines in the disease causing protein, ataxin-1. Several converging lines of evidence suggest that expanded ataxin-1 is toxic to neurons by causing increased histone acetylation, recruiting co-repressors and ultimately downregulating the transcription of a subset of genes involved in maintaining Purkinje cell structure and function. In our studies on ataxin-1, we have identified its interacting protein LANP as an excellent candidate mediator of neurodegeneration. This protein is a potent inhibitor of histone acetylation and transcription. In testing for a role of LANP in SCA1 pathogenesis, we have found that decreasing LANP levels in mice increases the levels of histone acetylation, an effect opposite to that induced by mutant ataxin-1. Moreover, we have also discovered that depleting LANP in neuronal cell-lines promotes neurite outgrowth, indeed, ameliorating the poor neurite outgrowth mediated by mutant ataxin-1. These results inspire the hypothesis that LANP plays a key role in SCA1 pathogenesis by serving as a mediator of toxicity in SCA1. Specifically, we postulate that LANP is recruited by ataxin-1 to cause persistent hypoacetylation at promoters of genes resulting in transcriptional aberrations and neuronal dysfunction. We would therefore predict that reducing LANP levels would reverse histone hypoacetylation seen in SCA1 and improve the phenotype. This exploratory/developmental grant proposes to test this intriguing hypothesis by depleting LANP in SCA1 mice and testing whether the SCA1 phenotype can be ameliorated as suggested by our in vitro work. This study would thus provide insights into a novel epigenetic pathogenic mechanism in SCA1. In addition, this study could lead to new therapies based on interfering with LANP function. This would represent an important breakthrough for patients with this otherwise incurable disease. PUBLIC HEALTH RELEVANCE: Spinocerebellar Ataxia Type 1 (SCA1) is an adult onset neurodegenerative disease caused by degeneration of the cerebellum and the brainstem. At a cellular level, it is characterized by alterations in gene expression in Purkinje cells and brainstem neurons brought about by mutant ataxin-1, the protein defective in this genetic disease. Our studies are aimed at attempting to reverse toxicity by inhibiting the functions of the ataxin-1 interacting protein LANP, a likely mediator of transcriptional derangements in this disease. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Our lab seeks to understand the biology of spinocerebellar ataxia type 1 (SCA1), a neurodegenerative disease that belongs to the family of disorders caused by the expansion of a polyglutamine (polyQ) tract in the disease protein. In SCA1 the polyglutamine repeat expansion occurs in the protein ataxin-1. Previous studies have established that the expanded polyQ tract alters ataxin-1's conformation, clearance, and ability to form complexes with native partner proteins. Within the first two weeks of life, however, long before behavioral or degenerative pathology is apparent, mutant ataxin-1 disrupts the transcription of specific genes. Although it is still unclear how this happens, we have uncovered one likely mechanism: we have found that cerebella of SCA1 mice exhibit hypoacetylation of histones, particularly at the promoters of down-regulated genes. This post-translational modification of histones is correlated with transcriptional repression. It is intriguing that We hypothesize that mutant ataxin-1 causes transcriptional repression by recruiting these corepressors to cause pathologic repression of target genes. Our preliminary findings support this hypothesis and suggest that genetically depleting one of these corepressors (LANP) improves both the ataxic phenotype and the neuropathology of SCA1 knock-in mice. To better understand the role of these corepressors in SCA1 pathogenesis we propose the following aims: (1) Characterize Sca1154Q/2Q mice lacking LANP with a range of behavioral, motor, and neuropathological assays to delineate the facets of the SCA1 phenotype improved by loss of LANP; (2) Elucidate the contribution of the histone deacetylase HDAC3 to Purkinje cell function and SCA1 pathology; and (3) Identify the direct targets of ataxin-1 repression and mechanistically probe how ataxin-1 modulates gene expression.

DESCRIPTION (Provided by Applicant): The ability of neurons to extend neurites is critical for synaptic formation and neuronal function. However, the molecular basis of neurite extension is largely unknown. To understand this fundamental process, the investigators have focused on the leucine-rich acidic nuclear protein (LANP), a protein that is expressed at particularly high levels in developing neurons from the early postnatal brain, in particular the cerebellum, at a time and location when neurons extend to processes to form functional networks. LANP is a nucleocytoplasmic shuttling protein. In the cytoplasm, LANP binds to all classes of structural microtubule-associated-proteins (MAPs);while in the nucleus LANP regulates transcription by inhibiting histone acetyl transferases (HATs). The investigators'preliminary data inspire the intriguing hypothesis that LANP plays a role in development by a dual role: (a) regulating the expression of genes critical for neurite outgrowth, and (b) modulating the properties of the neuronal cytoskeleton. This application makes use of the LANP null mice that the investigators have generated to address the role of LANP in neurite outgrowth. Defects in neurite outgrowth underlie a number of neurodevelopmental syndromes that negatively impact the life of young children and their care-givers. This application will help us to gain insights into the molecular basis of these disorders. RELEVANCE: Defects in proteins that regulate gene expression underlie a number of neurodevelopmental syndromes that negatively impact the quality of life of young patients and their care-givers. The investigators'laboratory is focusing on elucidating the properties of a protein called LANP that appear to play an important role as a regulator of neurite outgrowth.

DESCRIPTION (provided by applicant): Spinocerebellar ataxia type 1 (SCA1) is one of nine late-onset neurodegenerative diseases caused by the expansion of a polyglutamine (CAG) repeat. In the case of SCA1, the pathogenic glutamine expansion affects ataxin-1 (ATXN1), a protein that plays a role in transcriptional repression. We and others have found that in SCA1 genetic mouse models, mutant ATXN1 alters gene expression as early as two weeks after birth, long before behavioral signs and other pathological events become evident. Given the early nature of these transcriptional aberrations, we predicted that altered expression of a few key genes plays a mediatory role in pathogenesis. In the course of testing this prediction, we made the unexpected discovery that ATXN1 directly regulates the expression of the angiogenic and neurotrophic cytokine VEGF and that its levels are abnormally low in the SCA1 mouse brain. Following up on this observation, we discovered that genetically increasing VEGF levels mitigates the SCA1 phenotype in the well-characterized SCA1 knock-in mouse (SCA1154Q/2Q; Q=glutamine), the best existing mouse model of SCA1. We have also demonstrated in preliminary proof-of-principle experiments that VEGF delivered pharmacologically (by intraventricular delivery of recombinant VEGF) improves the cerebellar aspects of the SCA1 phenotype, specifically the hallmark ataxia and the cerebellar dendritic pathology. Motivated by these promising results, we wish to test two related hypotheses: that VEGF is an important cytokine for maintaining neurovascular health in the context of SCA1, and that VEGF has the potential to serve as therapy for this otherwise untreatable disease. We hope that these studies will provide mechanistic insights into the pathogenesis of SCA1 and also help design clinical trials for this disease. An important ancillary outcome of these studies is that they would shed light on the basic biology of VEGF in the nervous system and provide clues to its role in other neurodegenerative syndromes.

The lack of viable treatments for neurodegenerative diseases is becoming an increasingly pressing problem, as an ever-larger proportion of our population advances in years and becomes susceptible to these so far intractable conditions. The challenges are many: the brain is particularly delicate, complex, and inaccessible. We have been studying a particular neurodegenerative disease, Spinocerebellar ataxia type 1 (SCA1), which is one of a family of late-onset proteinopathies and thus a close cousin to Huntington's disease, Parkinson's, and amyotrophic lateral sclerosis. We made the unexpected discovery that ATXN1, the protein that is mutated in SCA1, directly regulates the expression of the angiogenic and neurotrophic cytokine VEGF; moreover, when mutated it causes the levels of VEGF to be abnormally low in the SCA1 mouse brain, causing pathological changes in the microvasculature as well as in the dendritic arborization of neurons. We have also demonstrated that these pathologies, and the motor incoordination that results from them, can be reversed by either genetic or pharmacologic replenishment of VEGF. There are severe limitations to the recombinant VEGF we had used in our study, however: it is extremely costly to manufacture, it is biologically unstable, and it is immunogenic. For these reasons, we have spent the past few years developing a completely new VEGF reagent with the help of our collaborator Dr. Sam Stupp, an internationally recognized expert in the field of nanotechnology and a collaborator on this grant. The reagent is a VEGF peptide amphiphile (VEGF-PA) that is less immunogenic and is designed to self-assemble in an aqueous environment into stable peptide amphiphile nanoparticles. Our preliminary data indicate that VEGF-PA is effective in SCA1 mice. In this proposal we will establish the feasibility of using VEGF-PA nano-peptide as a biochemically stable and inexpensive alternative to recombinant VEGF for long-term therapy for cerebellar degeneration. We hope that our studies will advance this nanotechnology toward clinical trials for treating SCA1. Given that deficiency in VEGF has been implicated in a wide range of neurodegenerative diseases including motor neuron disorders and Parkinson's disease, our work in SCA1 has the potential to revolutionize treatment for neurodegeneration. Moreover, these studies will pave the way for nanomedicine based treatments to be used to replace other neurotrophic factors, with broad ramifications for potential therapies for many diseases.

Project Summary Spinocerebellar ataxias (SCAs) are autosomal dominant neurodegenerative conditions characterized by cerebellar atrophy causing progressive motor incoordination (ataxia). Mechanistic insights into disease pathogenesis have been slow in coming, largely because many of the genes mutated encode for proteins whose function is still unknown. Consequently, no disease modifying therapy exists for these invalidating conditions. Recent data show that increased activity of one particular ion channel, TRPC3, which is highly enriched in the cerebellum and in cerebellar Purkinje cells in particular, is the cause of SCA41 and may also represent a shared mechanism in many SCAs. The TRPC3 gain-of-function in turn leads to impaired firing and neuronal toxicity. In this proposal we will take advantage of the ?moonwalker? mutant, a mouse model of SCA41 to test the therapeutic efficacy of TRPC3 blockade in slowing or stopping the course of the disease. The effectiveness of the treatment will be evaluated by quantification of behavioral, electrophysiological and pathological parameters.

Project Summary Giant axonal neuropathy (GAN) is an early-onset, autosomal recessive neurodegenerative disease that impacts the central and peripheral nervous systems. Pathologically, GAN is characterized by the disorganization and aggregation of intermediate filaments (IF). Formed from self-assembling subunits, the IF network spans the cell from the nucleus to the periphery. In GAN many cell types show abnormalities in the organization of IF, but neurons clearly bear the brunt of the pathology. Axons swell with the accumulation of neuronal IF, and degenerate to cause the neurological symptoms of GAN. The gene mutated in GAN encodes gigaxonin, a protein that belongs to the BTB/Kelch family of E3 ligase-like adaptor proteins. These proteins typically play a role in ubiquitin-proteasome mediated protein degradation. Based on our own data, we hypothesize that IF aggregation creates steric roadblocks in neurites that interfere with intracellular transport of organelles such as mitochondria, resulting in downstream pathology. This proposal comprehensively tests this model; at the same time, we will mechanistically dissect the steps of neurofilament degradation by gigaxonin, an important cell biological problem in itself.

Our lab studies the pathogenesis of spinocerebellar ataxia type 1?a neurodegenerative disorder caused by a pathogenic polyglutamine expansion in the protein ataxin-1 (ATXN1). This supplemental application is inspired by novel links between ATXN1 and Alzheimer?s disease (AD) pathogenesis. Most notably, recent Genome Wide Association Studies (GWAS) have identified variants in the ATXN1 gene that influence AD risk; moreover, ATXN1 protein?both wild type and expanded?modulate the levels of beta-secretase 1 (BACE1), a key protease involved in the cleavage of Amyloid Protein Precursor (APP) that results in the production of the amyloidogenic peptide A beta. The overarching hypothesis of this application, therefore, is that there are common pathways in these two otherwise disparate proteinopathies. We envisage that our experiments testing this hypothesis will lead to novel insights particularly in combating cognitive decline in both these syndromes.