Human Molecular Chaperone Hsp60 and Its Apical Domain Suppress Amyloid Fibril Formation of α-Synuclein

Heat shock proteins play roles in assisting other proteins to fold correctly and in preventing the aggregation and accumulation of proteins in misfolded conformations. However, the process of aging significantly degrades this ability to maintain protein homeostasis. Consequently, proteins with incorrect conformations are prone to aggregate and accumulate in cells, and this aberrant aggregation of misfolded proteins may trigger various neurodegenerative diseases, such as Parkinson’s disease. Here, we investigated the possibilities of suppressing α-synuclein aggregation by using a mutant form of human chaperonin Hsp60, and a derivative of the isolated apical domain of Hsp60 (Hsp60 AD(Cys)). In vitro measurements were used to detect the effects of chaperonin on amyloid fibril formation, and interactions between Hsp60 proteins and α-synuclein were probed by quartz crystal microbalance analysis. The ability of Hsp60 AD(Cys) to suppress α-synuclein intracellular aggregation and cytotoxicity was also demonstrated. We show that Hsp60 mutant and Hsp60 AD(Cys) both effectively suppress α-synuclein amyloid fibril formation, and also demonstrate for the first time the ability of Hsp60 AD(Cys) to function as a mini-chaperone inside cells. These results highlight the possibility of using Hsp60 AD as a method of prevention and treatment of neurodegenerative diseases

Evaluation of clinical, laboratorial and ultrasonographic predicting factors of malignancy in thyroid nodules

OBJECTIVE: To evaluate the risk of malignancy in thyroid nodules through clinical, laboratory, ultrasonographic and cytological aspects. PATIENTS AND METHODS: 741 nodules of 407 patients. RESULTS: The cytology was benign (60,5%), indeterminate (23,3%), malignant (8,3%) or nondiagnostic (7,6%). The prevalence of cancer in indeterminate citology was 18,5% (16% in follicular lesions, 44% in suspicious). The diagnosis of malignancy was 17,2% (n = 70). The frequency of cancer in women (15,2%) was lower than in men (27,9%). There was an inverse relation between age and cancer risk. There was no statistical significance in the prevalence of cancer according to number, size of nodules or TSH levels. Hypoechogenicity and microcalcifications on ultrasound were risk factors. CONCLUSION: The risk of malignancy was higher in men, hypoechoic nodules, with microcalcifications and was inversely related to age. The TSH level was not an independent factor predictive of malignancy.OBJETIVO: Avaliar risco de malignidade de nódulos tiroidianos por meio de aspectos clínicos, laboratoriais, ultrassonográficos e citológicos. PACIENTES E MÉTODOS: 741 nódulos de 407 pacientes. RESULTADOS: A citologia foi benigna (60,5%), indeterminada (23,3%), maligna (8,6%) ou não diagnóstica (7,6%). A prevalência de câncer nas citologias indeterminadas foi 18,5% (16% nas lesões foliculares, 44% nas suspeitas). O diagnóstico de malignidade foi 17,2% (n = 70). A frequência de câncer em mulheres (15,2%) foi menor do que em homens (27,9%). Houve uma relação inversa entre idade e risco de câncer. Não houve significância estatística na prevalência de câncer de acordo com número, tamanho dos nódulos ou níveis de TSH. Hipoecogenicidade e microcalcificações ao ultrassom foram fatores de risco. CONCLUSÃO: O risco de malignidade foi maior em homens, nódulos hipoecogênicos, com microcalcificações e inversamente relacionado à idade. O nível de TSH não foi um preditor independente de malignidade.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MedicinaInstituto Israelita de Ensino e Pesquisa Albert Einstein Centro de Doenças TiroidianasFleury Medicina e SaúdeUNIFESP, EPM, Depto. de MedicinaSciEL

Like a bolt from the blue : phthalocyanines in biomedical optics

The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs

Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes

Biologia reprodutiva de Sphoeroides testudineus (Linnaeus) (Pisces, Osteichthyes, Tetraodontidae) da gamboa do Baguaçu, Baía de Paranaguá, Paraná, Brasil Reproduetive biology of Sphoeroides testudineus (Linneus) (Pisces, Osteichthyes, Tetraodontidae) of the gamboa do Baguaçu, bay of Paranaguá, State of Paraná, Brazil

<abstract language="eng">The present study seeks to elucidatc reproduetive aspects of Sphoeroides testudineus (Linnaeus, 1758), Tetraodontidae. Monthly collections were accomplished for one year (November/98-October/99), in the gamboa do Baguaçu, Bay of Paranaguá with a Fyke net. The macroscopic analysis of the gonad stages allowed us to estimate the sexual proportion as 1:1 during the whole period, except in the months of May and October, when the proportions of two females for one male and two males for one female were observed respectively. The analysis of the relative frequency of the monthly gonad stages and the Curve of Maturation aided in the determination of the reproduetive period, that oceurred from September to January. Microscopic analyses of the female gonads allowed us to characterize four develo-pment phases of the ovarian follicle, six stages of ovarian development and the type of spawn, which was parceled. The first maturation for females was estimated to be betwecn 10-11 cm of length

In Vivo Assessment of Acute UVB Responses in Normal and Xeroderma Pigmentosum (XP-C) Skin-Humanized Mouse Models

In vivo studies of UVB effects on human skin are precluded by ethical and technical arguments on volunteers and inconceivable in cancer-prone patients such as those affected with Xeroderma Pigmentosum (XP). Establishing reliable models to address mechanistic and therapeutic matters thus remains a challenge. Here we have used the skin-humanized mouse system that circumvents most current model constraints. We assessed the UVB radiation effects including the sequential changes after acute exposure with respect to timing, dosage, and the relationship between dose and degree-sort of epidermal alteration. On Caucasian-derived regenerated skins, UVB irradiation (800 J/m2) induced DNA damage (cyclobutane pyrimidine dimers) and p53 expression in exposed keratinocytes. Epidermal disorganization was observed at higher doses. In contrast, in African descent–derived regenerated skins, physiological hyperpigmentation prevented tissue alterations and DNA photolesions. The acute UVB effects seen in Caucasian-derived engrafted skins were also blocked by a physical sunscreen, demonstrating the suitability of the system for photoprotection studies. We also report the establishment of a photosensitive model through the transplantation of XP-C patient cells as part of a bioengineered skin. The inability of XP-C engrafted skin to remove DNA damaged cells was confirmed in vivo. Both the normal and XP-C versions of the skin-humanized mice proved proficient models to assess UVB-mediated DNA repair responses and provide a strong platform to test novel therapeutic strategies