Browsing by Author "Cardoso, Rita"
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- Apicomplexans pulling the strings: manipulation of the host cell cytoskeleton dynamicsPublication . Cardoso, Rita; Soares, Helena; Hemphill, Andrew; Leitão, AlexandreInvasive stages of apicomplexan parasites require a host cell to survive, proliferate and advance to the next life cycle stage. Once invasion is achieved, apicomplexans interact closely with the host cell cytoskeleton, but in many cases the different species have evolved distinct mechanisms and pathways to modulate the structural organization of cytoskeletal filaments. The host cell cytoskeleton is a complex network, largely, but not exclusively, composed of microtubules, actin microfilaments and intermediate filaments, all of which are modulated by associated proteins, and it is involved in diverse functions including maintenance of cell morphology and mechanical support, migration, signal transduction, nutrient uptake, membrane and organelle trafficking and cell division. The ability of apicomplexans to modulate the cytoskeleton to their own advantage is clearly beneficial. We here review different aspects of the interactions of apicomplexans with the three main cytoskeletal filament types, provide information on the currently known parasite effector proteins and respective host cell targets involved, and how these interactions modulate the host cell physiology. Some of these findings could provide novel targets that could be exploited for the development of preventive and/or therapeutic strategies.
- Besnoitia besnoiti and Toxoplasma gondii: two apicomplexan strategies to manipulate the host cell centrosome and Golgi apparatusPublication . Cardoso, Rita; Nolasco, Sofia; Gonçalves, João; Cortes, Helder C.; Leitão, Alexandre; Soares, HelenaBesnoitia besnoiti and Toxoplasma gondii are two closely related parasites that interact with the host cell microtubule cytoskeleton during host cell invasion. Here we studied the relationship between the ability of these parasites to invade and to recruit the host cell centrosome and the Golgi apparatus. We observed that T. gondii recruits the host cell centrosome towards the parasitophorous vacuole (PV), whereas B. besnoiti does not. Notably, both parasites recruit the host Golgi apparatus to the PV but its organization is affected in different ways. We also investigated the impact of depleting and over-expressing the host centrosomal protein TBCCD1, involved in centrosome positioning and Golgi apparatus integrity, on the ability of these parasites to invade and replicate. Toxoplasma gondii replication rate decreases in cells over-expressing TBCCD1 but not in TBCCD1-depleted cells; while for B. besnoiti no differences were found. However, B. besnoiti promotes a reorganization of the Golgi ribbon previously fragmented by TBCCD1 depletion. These results suggest that successful establishment of PVs in the host cell requires modulation of the Golgi apparatus which probably involves modifications in microtubule cytoskeleton organization and dynamics. These differences in how T. gondii and B. besnoiti interact with their host cells may indicate different evolutionary paths.
- Frailty and nutritional status in institutionalized elderly patients with neurodegenerative disordersPublication . Miranda, Diana; Costa, Vânia; Cardoso, Rita; Gonçalves, Nilza; Castro-Caldas, Ana; Ferreira, Joaquim J.Introduction: Frailty is a geriatric syndrome defined as a state of increased vulnerability to negative health outcomes that is considered the most powerful predictor of disability, dependence, institutionalization, and death, and so considered a major health burden. Malnutrition has been described to be independently associated with frailty. Objectives: The primary objective was to describe the frequency of frailty in institutionalized patients with neurodegenerative disorders. Secondary objectives were to describe the frequency of undernutrition and to evaluate the correlation between frailty and nutritional status. Methods: A cross-sectional observational pilot study was performed. All patients aged 65 years and older with at least one neurodegenerative disorder admitted in CNS- Campus Neurológico were included. A nutritional assessment, through the Mini Nutritional Assessment (MNA), anthropometric measurements and the Edinburgh Feeding Evaluation in Dementia Questionnaire (EdFED-Q), and a frailty assessment, through the Marigliano-Cacciafesta Polypathological Scale (MCPS) and the Clinical Frailty Scale (CFS), were conducted. Results: 76 participants were included with a mean age of 76±6.8 years. Parkinsonian syndromes represented 82.9% of the sample. The frequency of frailty was 71.1%. Patients with atypical parkinsonism were significantly frailer than patients with Parkinson’s disease (PD) (85.7 and 60%, respectively). 69.3% of the patients with dementia were frail. The frequency of undernutrition (and risk of) was 73.7%. Although not statistically significant, undernutrition was more frequent in dementia syndromes, followed by atypical parkinsonism and PD (30.8, 21.2, and 10%, respectively). Significant correlations were found between all the nutritional assessment parameters and the MCPS, being the strongest with the MNA and the EdFED-Q. Conclusions: The prevalence of frailty in institutionalized patients with neurodegenerative disorders is high, along with the prevalence of undernutrition. Frailty and nutritional status parameters share significant correlations.