Gomes-Santos, Carina S S; Itoe, Maurice A; Afonso, Cristina; Henriques, Ricardo; Gardner, Rui; Sepúlveda, Nuno; Simões, Pedro D; Raquel, Helena; Almeida, António Paulo; Moita, Luis F; Frischknecht, Friedrich; Mota, Maria M
Plasmodium sporozoites are transmitted by Anopheles mosquitoes and infect hepatocytes, where a single sporozoite replicates into thousands of merozoites inside a parasitophorous vacuole. The nature of the Plasmodium-host cell interface, as well as the interactions occurring between these two organisms, remains largely unknown. Here we show that highly dynamic hepatocyte actin reorganization events occur around developing Plasmodium berghei parasites inside human hepatoma cells. Actin reorganization is most prominent between 10 to 16 hours post infection and depends on the actin severing and capping protein, gelsolin. Live cell imaging studies also suggest that the hepatocyte cytoskeleton may contribute to parasite elimination...
Gonçalves, Susana A; Macedo, Diana; Raquel, Helena; Simões, Pedro D; Giorgini, Flaviano; Ramalho, José S; Barral, Duarte C; Ferreira Moita, Luís; Outeiro, Tiago Fleming
Alpha-Synuclein (aSyn) misfolding and aggregation is common in several neurodegenerative diseases, including Parkinson's disease and dementia with Lewy bodies, which are known as synucleinopathies. Accumulating evidence suggests that secretion and cell-to-cell trafficking of pathological forms of aSyn may explain the typical patterns of disease progression. However, the molecular mechanisms controlling aSyn aggregation and spreading of pathology are still elusive. In order to obtain unbiased information about the molecular regulators of aSyn oligomerization, we performed a microscopy-based large-scale RNAi screen in living cells. Interestingly, we identified nine Rab GTPase and kinase genes that modulated aSyn aggregation, toxicity and levels. From those,...
Harriff, Melanie J.; Karamooz, Elham; Burr, Ansen; Grant, Wilmon F.; Canfield, Elizabeth T.; Sorensen, Michelle L.; Moita, Luis F.; Lewinsohn, David M.
Mucosal-Associated Invariant T (MAIT) cells, present in high frequency in airway and other mucosal tissues, have Th1 effector capacity positioning them to play a critical role in the early immune response to intracellular pathogens, including Mycobacterium tuberculosis (Mtb). MR1 is a highly conserved Class I-like molecule that presents vitamin B metabolites to MAIT cells. The mechanisms for loading these ubiquitous small molecules are likely to be tightly regulated to prevent inappropriate MAIT cell activation. To define the intracellular localization of MR1, we analyzed the distribution of an MR1-GFP fusion protein in antigen presenting cells. We found that MR1 localized to...
Velho, Tiago R; Santos, Isa; Póvoa, Pedro; Moita, Luis Ferreira
Sepsis is a life-threatening condition that arises as a systemic inflammatory response syndrome to an infection. Its uncontrolled progression can in frequent cases lead to multiple organ failure, which is still associated with high mortality rates. Modern antibiotics made clear that the infection is only an initiating, and not always necessary, event of this syndrome as many patients with sepsis die despite effective eradication of the inciting pathogen. This observation critically contributed to a paradigm shift that focused the pathogenesis of sepsis on the host and not on the pathogen. However, therapeutic strategies based on the inhibition of proinflammatory critical...