da Silva, R. A. | bioRxiv Science

bioRxiv2026

Label-Free Proteomics of α-Synuclein-Expressing Caenorhabditis elegans Model Uncovers Conserved Pathophysiological Pathways in Parkinson's Disease

Parkinsons disease (PD) is the second most prevalent neurodegenerative disease in the elderly population, characterized by a wide variety of motor and non-motor symptoms. Its complex biochemical and molecular mechanisms make it challenging to study PD directly in patients or to replicate it in vitro, underscoring the need for careful model characterization to advance translational research. The free-living nematode Caenorhabditis elegans has been widely used in neuroscience studies. Technological advancements enabled the development of transgenic strains that mimic aspects of neurodegenerative diseases, such as the OW13 strain [grk-1(ok1239) X; pkIs2386 IV (unc-54p::alpha-synuclein::YFP + unc-119(+))], which expresses human -synuclein in body wall muscle cells in a sensitized G-protein coupled receptor kinase-deficient background. This study conducted an exploratory proteomic analysis of the OW13 strain. A cross-species comparative analysis using post-mortem substantia nigra proteomics from PD individuals identified a convergent signature of 76 conserved C. elegans proteins, corresponding to 70 human orthologs, derived from the 373 DAPs. Among these conserved candidates, 68 proteins were upregulated, and 8 were downregulated. Functional enrichment linked these DAPs to the tricarboxylic acid cycle, mitochondrial function, and protein quality control, suggesting that -synuclein aggregation triggers a broad proteostatic and bioenergetic remodeling resembling PD pathophysiology. This first proteomic and cross-species characterization of the OW13 strain strongly supports C. elegans as a robust PD model.

neuroscience↗

bioRxiv2024

Interstitial pneumonia via the oropharyngeal route of infection with Encephalitozoon cuniculi

Microsporidia causes opportunistic infections in immunosuppressed individuals. Mammals shed these spores of fungi in feces, urine, or respiratory secretions, which could contaminate water and food, thereby reaching the human body and causing infection. The oral route is the most common route of infection, although experiments have demonstrated that intraperitoneal and intravenous routes may also spread infection. Respiratory tract infection, although considered to be possible, has not been reported to date. The present study, therefore, aimed to demonstrate infection with the microsporidia of Encephalitozoon cuniculi via the oropharyngeal route as a model for opportunistic pneumonia. The objectives were the study of opportunistic pneumonia in general while also confirming transmission via the respiratory route to expand the understanding of the epidemiology of zoonoses. C57BL mice, both male and female, up to 12 weeks of age, and free of specific pathogens (SPF) were inoculated (Infected group) or not infected (Non-Infected group) with 1 x 107 spores of E. cuniculi via the oropharyngeal route. The animals immunosuppressed with cyclophosphamide (Cy) were infected (Cy-Infected group) or not infected (Cy-Uninfected group), and then assessed for the influence of immunosuppression on infection. In both groups, animals inoculated with 0.9% saline solution via the oropharyngeal route served as controls (Sham and Cy-Sham groups, respectively). After 14 days of infection, the lungs of all animals were retrieved for histopathological analysis, phenotyping of lung inflammatory cells using flow cytometry, measurement of fungal load using qPCR, and measurement of the serum levels of Th1, Th2, and Th17 cytokines. The results revealed that the infected animals developed interstitial pneumonia characterized by perialveolar inflammatory infiltrative lesions with a predominance of lymphocytes and plasma cells. However, the fungal load and the extent of the inflammatory infiltrate were relatively lower in the Cy-Infected group, with a predominance of the CD8+ T lymphocyte population in the lungs compared to Infected group. In the Infected group not treated with Cy, an increase in the population of alveolar macrophages (F4/80+CD11b-SiglecF+) was noted, along with higher fungal load and inflammatory infiltrate in the lungs, indicating a further pronounced Encephalitozoon pneumonia compared to the immunosuppressed animals. The infected groups presented Th1 cytokine profiles, with the Cy-Infected group exhibiting increased Th17 levels. Collectively, these results demonstrated that oropharyngeal infection promoted pneumonia caused by E. cuniculi in mice treated or not with cyclophosphamide, with greater severity occurring in the non-immunosuppressed mice, thereby establishing this model as a suitable one for interstitial pneumonia via aspiration. Author SummaryOpportunistic fungi infection in immunosuppressed individuals may lead to pneumonia that is lethal. The airways are the most common routes for these infections. The opportunistic fungal species Encephalitozoon cuniculi is associated with pneumonia, although this species has not been reported to cause airway infection to date. The present study aimed to demonstrate that the oropharyngeal route, which is a frequent route of infection in patients with reflux, could lead to severe pneumonia in the mice without immunosuppression associated with a low CD8+ T lymphocyte response.

pathology↗

bioRxiv2023

Exposure to Zika and chikungunya viruses impacts aspects of the vectorial capacity of Aedes aegypti and Culex quinquefasciatus

Zika (ZIKV) and chikungunya (CHIKV) are arboviruses that cause infections in humans and can causeclinical complications, representing a worldwide public health problem. Aedes aegypti is the primary vector of these pathogens and Culex quinquefasciatusmay be a potential ZIKV vector. This study aimed to evaluate fecundity, fertility, survival, longevity, and blood feeding activity in Ae. aegypti after exposure to ZIKV and CHIKV and, in Cx. quinquefasciatusexposed to ZIKV.Three colonies were evaluated: AeCamp(Ae. aegypti -field),RecL (Ae. aegypti - laboratory)and CqSLab (Cx. quinquefasciatus - laboratory). Seven to 10 days-old females from these colonies were exposed to artificial blood feeding with CHIKV or ZIKV. CHIKV caused reduction in fecundity and fertilityinthe natural population, AeCamp and reduction in survival and fertility in RecL.ZIKV impacted survival in RecL, fertility in AeCamp. and fecundity and fertility in CqSLab. Both viruses had no effect on blood feeding activity. These results show that CHIKV produces a higher biological cost in Ae. aegypti, compared to ZIKV, and ZIKV differently alters the biological performance in colonies of Ae. aegypti and Cx. quinquefasciatus. These results provide a better understanding over the processes of virus-vector interaction and can shed light on the complexity of arbovirus transmission.

microbiology↗