Discovery of Therapeutic Approaches for Polyglutamine Diseases: A Summary of Recent Efforts

Polyglutamine (PolyQ) diseases are a group of neurodegenerative disorders caused by the expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the coding region of specific genes. This leads to the production of pathogenic proteins containing critically expanded tracts of glutamines. Although polyQ diseases are individually rare, the fact that these nine diseases are irreversibly progressive over 10 to 30 years, severely impairing and ultimately fatal, usually implicating the full-time patient support by a caregiver for long time periods, makes their economic and social impact quite significant. This has led several researchers worldwide to investigate the pathogenic mechanism(s) and therapeutic strategies for polyQ diseases. Although research in the field has grown notably in the last decades, we are still far from having an effective treatment to offer patients, and the decision of which compounds should be translated to the clinics may be very challenging. In this review, we provide a comprehensive and critical overview of the most recent drug discovery efforts in the field of polyQ diseases, including the most relevant findings emerging from two different types of approaches-hypothesis-based candidate molecule testing and hypothesis-free unbiased drug screenings. We hereby summarize and reflect on the preclinical studies as well as all the clinical trials performed to date, aiming to provide a useful framework for increasingly successful future drug discovery and development efforts.Project ON.2 SR&TD Integrated Program (NORTE-07-0124-FEDER-000021), co-funded by North Portugal Regional Operational Program (ON.2-O Novo Norte), under the National Strategic Reference Framework, through the European Regional Development Fund (ERDF) and also supported by Fundação para a Ciência e Tecnologia through the project POCI-01-0145-FEDER-016818 (PTDC/NEU-NMC/3648/2014)info:eu-repo/semantics/publishedVersio

Pharmacological promotion of inclusion formation: A therapeutic approach for Huntington’s and Parkinson’s diseases

Misfolded proteins accumulate in many neurodegenerative diseases, including huntingtin in Huntington’s disease and α-synuclein in Parkinson’s disease. The disease-causing proteins can take various conformations and are prone to aggregate and form larger cytoplasmic or nuclear inclusions. One approach to the development of therapeutic intervention for these diseases has been to identify chemical compounds that reduce the size or number of inclusions. We have, however, identified a compound that promotes inclusion formation in cellular models of both Huntington’s disease and Parkinson’s disease. Of particular interest, this compound prevents huntingtin-mediated proteasome dysfunction and reduces α-synuclein-mediated toxicity. These results demonstrate that compounds that increase inclusion formation may actually lessen cellular pathology in both Huntington’s and Parkinson’s diseases, suggesting a therapeutic approach for neurodegenerative diseases caused by protein misfolding

Metastatic solid tumors to the jaw and oral soft tissue: A retrospective clinical analysis of 44 patients from a single institution

PURPOSE: Metastatic solid tumors to the oral cavity are rare, frequently indicative of an end-stage disease process, and associated with poor survival rates. We performed a 20-year retrospective clinical analysis of our institution’s cases of solid metastases to the oral cavity, and investigated these patients’ clinical outcomes. MATERIAL AND METHODS: A retrospective study of patients with metastatic solid tumors to the oral cavity over a 20-year period (October 1996 to September 2015) was conducted at Memorial Sloan Kettering Cancer Center. Patients were selected if they had a histopathologically confirmed diagnosis. Demographic, pathologic, and clinical information were reviewed to identify patient outcomes. RESULTS: A total of 44 patients with metastatic non-melanocytic non-hematopoietic tumor to the oral cavity were identified: 24 males and 20 females (39 adults and 5 children) with a mean age of 54.3 years. In all, 24 cases involved the jaw and 20 cases involved the oral soft tissue. Eight patients (18.2%) had oral cavity metastases as the first indication of an occult malignancy. In adult patients, the common primary sites were the lungs (n = 9, 20%), kidney (n = 7, 16%), breast (n = 5, 11%), and colon (n = 4, 9%); and in pediatric patients the adrenal gland (3/5) was the most common site. Of the adult patients, 33 (84.6%) died of disease. From the time of metastasis diagnosis, patients with jaw metastases had a median and mean survival of 12 months and 27.7 months, respectively. In comparison, patients with oral soft tissue metastases had a median survival time of 5 months, and mean of 8 months. One pediatric patient (20%) died of disease 8 months after metastasis diagnosis. CONCLUSION: Metastatic solid tumors to the oral cavity can be the first sign of a malignancy. Pediatric patients with oral cavity metastases have a better prognosis compared to adult patients. In this series, adults with oral soft tissue involvement had shorter survival times compared to patients with jaw involvement

Protein aggregation into insoluble deposits protects from oxidative stress

Protein misfolding and aggregation have been associated with the onset of neurodegenerative disorders. Recent studies demonstrate that the aggregation process can result in a high diversity of protein conformational states, however the identity of the specific species responsible for the cellular damage is still unclear. Here, we use yeast as a model to systematically analyse the intracellular effect of expressing 21 variants of the amyloid-ß-peptide, engineered to cover a continuous range of intrinsic aggregation propensities. We demonstrate the existence of a striking negative correlation between the aggregation propensity of a given variant and the oxidative stress it elicits. Interestingly, each variant generates a specific distribution of protein assemblies in the cell. This allowed us to identify the aggregated species that remain diffusely distributed in the cytosol and are unable to coalesce into large protein inclusions as those causing the highest levels of oxidative damage. Overall, our results indicate that the formation of large insoluble aggregates may act as a protective mechanism to avoid cellular oxidative stress.We thank Cristina Visentin for help with H2O2 and catalase measurements. This work was funded by the Spanish Ministry of Economy and Competitiveness (BFU2013-44763-P and BIO2016-783-78310-R to S.V.). S.V. has been granted an ICREA ACADEMIA award