Tissue Degeneration following Loss of Schistosoma mansoni cbp1 Is Associated with Increased Stem Cell Proliferation and Parasite Death In Vivo
Fig 5
cbp1 is essential for schistosome survival in vivo.
(A) Images of control and cbp1 RNAi-treated worms during in vitro culture. Until at least D19 of in vitro culture, control(RNAi) animals remain as male and female worm pairs, are firmly attached to the substrate, and maintain vigorous movement. By D8 of in vitro culture, cbp1(RNAi) animals become unpaired and fail to firmly attach to the substrate. Over time, movements of cbp1(RNAi) worms become less vigorous and oftentimes their heads curled ventrally (Cyan box, D15 time point). Cartoon depicting surgical procedure to examine the requirement for cbp1 function in vivo. (C) Images of three mice that were transplanted with control or cbp1 RNAi-treated parasites following hepatic vein perfusion. Unlike mice that received control(RNAi) worms, livers from mice receiving cbp1(RNAi) worms were normal-sized and the mice had few signs of infection. Plot showing quantification of the percent recovery of control and cbp1 RNAi-treated parasites from mice. Each dot represents percent recovery from an individual mouse. Two separate sets of transplantations were performed with n = 5 mice for controls and n = 8 mice for cbp1(RNAi). p < 0.0001, t-test. Representative livers from mice transplanted with control or cbp1 RNAi-treated parasites. Livers from mice that received control(RNAi) parasites were large and contained large numbers of granulomas. Livers from mice receiving cbp1(RNAi) parasites were normal sized and contained very few granulomas. Few large granuloma-like structures were often found at the periphery of livers from mice that received cbp1(RNAi) worms (arrowhead in inset). Plot depicting number of schistosome eggs per liver section from mice transplanted with control or cbp1 RNAi-treated parasites. Each dot represents the mean number of eggs counted from two liver sections from an individual mouse. n = 4 livers for both control and cbp1 RNAi treatment groups. H&E staining of liver tissue from mice transplanted with control or cbp1 RNAi-treated worms. Arrowheads point to eggs inside granulomas. Large granuloma-like masses in livers of mice from cbp1(RNAi) treatment group correspond to worms at various stages of degeneration. Left panel shows a male worm with a clearly identifiable tegument and intestine (labeled teg and gut in inset, respectively) surrounded by neutrophils and lymphocytes. As panels move to the right, worms appear to become structurally compromised and lesions contain more host fibroblasts, suggesting these lesions possess a more mature immune response to the parasites. Scale Bars: A,E 1 mm; G-H 100 μm.