Preferential infection of dividing cells by Cryptosporidium parvum

Widmer, Giovanni; Yang, Yilin; Bonilla, R.; Tanriverdi, Sultan; Ciociola, Kristina M.

doi:10.1017/s0031182006000151

Cited by 14 publications

(11 citation statements)

References 33 publications

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“…The long-term maintenance of Cryptosporidium in cell culture has been reported previously (12), and recent studies have evaluated the effects of oocyst treatment on excystation (14) and host cell growth phase (32). Future research aimed at optimizing oocyst pretreatment and cell monolayer growth conditions will hopefully allow progress in this important area.…”

Section: Discussionmentioning

confidence: 98%

Aged HCT-8 Cell Monolayers Support Cryptosporidium parvum Infection

Sifuentes

Giovanni

2007

Appl Environ Microbiol

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Cell culture assays in various formats have been used to study the infectivity of Cryptosporidium spp. as well as to determine the infectivity of naturally occurring oocysts in water. Currently, cell culture assays for infectious Cryptosporidium spp. in water have largely been limited to practice in research laboratories. One obstacle to the routine use of Cryptosporidium cell culture assays for the analysis of water samples is the coordination of water sample collection and processing with readiness of cell culture monolayers. For most Cryptosporidium cell culture assays, monolayers are allowed to develop for 24 to 48 h to reach 80 to 100% confluence prior to inoculation. In this study, we used immunofluorescent assay microscopy to evaluate freshly confluent (2-day-old) and aged (8-to 67-day-old) HCT-8 cell monolayers for their ability to support Cryptosporidium parvum infection. HCT-8 monolayers as old as 67 days were clearly shown to support infection. In two of three experiments, aged monolayers (8-to 11-day-old and 11-to 22-day-old, respectively) developed the same number of C. parvum clusters of infection as freshly confluent monolayers. Results suggest that it may be possible to use cell monolayers from freshly confluent to 3 weeks old on hand for infectivity assays without having to schedule sample processing to coincide with development of freshly confluent monolayers. This would make Cryptosporidium cell culture assays much more feasible for water quality and utility laboratories.

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Section: Discussionmentioning

confidence: 98%

Aged HCT-8 Cell Monolayers Support Cryptosporidium parvum Infection

Sifuentes

Giovanni

2007

Appl Environ Microbiol

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“…To this point, the intestinal epithelium that abounds in nutrients represents a suitable environment for a parasite that is auxotrophic for so many essential metabolites. Moreover, a previous study reported the predilection of C. parvum for infecting dividing enterocytes that contain more metabolites than stationary cells (Widmer et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Cryptosporidium parvumscavenges LDL-derived cholesterol and micellar cholesterol internalized into enterocytes

et al. 2013

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Cryptosporidium spp. are responsible for devastating diarrhea in immunodeficient individuals. In the intestinal tract, the developmental stages of the parasite are confined to the apical surfaces of epithelial cells. Upon invasion, Cryptosporidium incorporates the microvillous membrane of the enterocyte to form the parasitophorous vacuole (PV) and sequesters itself from the host cytoplasm by rearranging the host cytoskeleton. Cryptosporidium parvum has minimal anabolic capabilities and relies on transporters and salvage pathways to meet its basic metabolic requirements. The cholesterol salvage pathway is crucial for the development of protozoan parasites. In this study, we have examined the sources of cholesterol from C. parvum infecting enterocytes. We illustrated that the intracellular stages of Cryptosporidium as well as the oocysts shed by the host, contain cholesterol. Incubation of infected enterocytes in lipoprotein-free medium impairs parasite development and results in substantial decrease in cholesterol content associated with the PV. Among lipoproteins, LDL constitutes an important source of cholesterol for Cryptosporidium. Dietary cholesterol incorporated into micelles is internalized into enterocytes by the NPC1L1 transporter. We showed that C. parvum also obtains cholesterol from micelles in enterocytes. Pharmacological blockade of NPC1L1 function by ezetimibe or moderate down-regulation of NPC1L1 expression decreases parasite infectivity. These observations indicate that, despite its dual sequestration from the intestinal lumen and the host cytoplasm, C. parvum can, in fact, obtain cholesterol both from the gut’s lumen and the host cell. This study highlights the evolutionary advantages for epicellular pathogens to access to nutrients from the outside and inside of the host cell.

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“…Survivin is required to preserve viability of dividing cells and is specifically involved in S phase and G 2 /M phase cell cycle progression (1,6,34). It is interesting to note that C. parvum infection and development have a significant preference for mitotic cells in S/G 2 /M phase cells (65). Inhibition of caspase activation was sensitive to both XIAP and survivin gene expression knockdown.…”

Section: Discussionmentioning

confidence: 99%

“…In vivo, intestinal epithelial cells are governed by the Wnt gradient, which forms undifferentiated cells at the crypt and fully differentiated and dying cells at the villus tip (51,59). In vivo, C. parvum appears to replicate in the basal crypt cells (52), and parasite development has a significant preference for mitotic cells in S/G 2 /M phase cells (65). Survivin also has a role in cell cycle progression (1,6,34), and its expression is controlled by cell cycle pathway components such as Myc and PTEN that are active only in the undifferentiated cells (12,19).…”

Section: Discussionmentioning

confidence: 99%