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Transcriptome and histopathological changes in mouse brain infected with Neospora caninum.

Nishimura M, Tanaka S, Ihara F, Muroi Y, Yamagishi J, Furuoka H, Suzuki Y, Nishikawa Y - Sci Rep (2015)

Bottom Line: A GOstat analysis predicted that the upregulated genes were involved in the host immune response.Genes whose expression correlated positively and negatively with parasite numbers were involved in the host immune response, and neuronal morphogenesis and lipid metabolic processes, respectively.These results suggest that changes in the gene expression profile associated with neuronal functions as well as immune responses can contribute to the pathogenesis in N. caninum-infected animals.

View Article: PubMed Central - PubMed

Affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, Japan.

ABSTRACT
Neospora caninum is a protozoan parasite that causes neurological disorders in dogs and cattle. It can cause nonsuppurative meningoencephalitis and a variety of neuronal symptoms are observed, particularly in dogs. However, the pathogenic mechanism, including the relationship between the parasite distribution and the clinical signs, is unclear. In this study, to understand the pathogenic mechanism of neosporosis, parasite distribution and lesions were assessed in the brain of mice infected with N. caninum (strain Nc-1). Host gene expression was also analyzed with RNA sequencing (RNA-Seq). The histopathological lesions in the frontal lobe and the medulla oblongata were significantly more severe in symptomatic mice than in asymptomatic mice, although no association between the severity of the lesions and parasite numbers was found. In infected mice, the expression of 772 mouse brain genes was upregulated. A GOstat analysis predicted that the upregulated genes were involved in the host immune response. Genes whose expression correlated positively and negatively with parasite numbers were involved in the host immune response, and neuronal morphogenesis and lipid metabolic processes, respectively. These results suggest that changes in the gene expression profile associated with neuronal functions as well as immune responses can contribute to the pathogenesis in N. caninum-infected animals.

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Histopathological lesions and parasite distributions in different areas of N. caninum-infected mouse brains.(A–D) Histopathological lesions in mouse brains infected with N. caninum (n = 17). To estimate the severity of the histopathological lesions, the lesions were scored as follows: (A) localized perivascular cuff (score 1), (B) local gliosis (score 2), (C) focal necrosis with moderate inflammatory cell infiltration (score 3), and (D) severe glial cell and macrophage infiltration, and rarefaction of the neuropil in extensive necrotic foci (score 4). (E) The total pathological scores for different mouse brain areas were determined as described in the Materials and Methods (ten symptomatic and seven asymptomatic mice). *p < 0.05 and **p < 0.01 (unpaired Student's t-test). (F) After DNA extraction from N. caninum-infected mouse brain samples (four symptomatic and two asymptomatic mice) and paraffin-embedded brain tissues, including the medulla oblongata and cerebellum (ten symptomatic and seven asymptomatic mice), parasite numbers were quantified by real-time PCR using primers specific for the N. caninum Nc5 gene.
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f2: Histopathological lesions and parasite distributions in different areas of N. caninum-infected mouse brains.(A–D) Histopathological lesions in mouse brains infected with N. caninum (n = 17). To estimate the severity of the histopathological lesions, the lesions were scored as follows: (A) localized perivascular cuff (score 1), (B) local gliosis (score 2), (C) focal necrosis with moderate inflammatory cell infiltration (score 3), and (D) severe glial cell and macrophage infiltration, and rarefaction of the neuropil in extensive necrotic foci (score 4). (E) The total pathological scores for different mouse brain areas were determined as described in the Materials and Methods (ten symptomatic and seven asymptomatic mice). *p < 0.05 and **p < 0.01 (unpaired Student's t-test). (F) After DNA extraction from N. caninum-infected mouse brain samples (four symptomatic and two asymptomatic mice) and paraffin-embedded brain tissues, including the medulla oblongata and cerebellum (ten symptomatic and seven asymptomatic mice), parasite numbers were quantified by real-time PCR using primers specific for the N. caninum Nc5 gene.

Mentions: Pathological severity was evaluated in 17 mice, and 10 of the 17 mice showed clinical signs of neosporosis including febrile responses and leg paralysis 39 days after infection (See Figure 1A). Seven of 10 symptomatic mice showed neurological signs, including circling motion, head tilting, and leg paralysis. We analyzed the nine area of brain histopathologically and for the quantification of parasite load. Histopathological lesions, including perivascular cuff, mononuclear cellular meningitis, glial cell activation, and focal necrosis, were observed in the brains of all 17 mice, which are similar to the lesions found in dogs891415. Each focal lesion was scored for severity using a scale from 1 to 4 (See Figure 2A–D). The total pathological scores for all areas in the brain are shown in Figure 2E. The total scores for the frontal lobe and medulla oblongata were significantly higher in the symptomatic mice than in the asymptomatic mice. Although there were no significant differences between the symptomatic and asymptomatic mice in the cerebellum, two symptomatic mice showed very high scores.


Transcriptome and histopathological changes in mouse brain infected with Neospora caninum.

Nishimura M, Tanaka S, Ihara F, Muroi Y, Yamagishi J, Furuoka H, Suzuki Y, Nishikawa Y - Sci Rep (2015)

Histopathological lesions and parasite distributions in different areas of N. caninum-infected mouse brains.(A–D) Histopathological lesions in mouse brains infected with N. caninum (n = 17). To estimate the severity of the histopathological lesions, the lesions were scored as follows: (A) localized perivascular cuff (score 1), (B) local gliosis (score 2), (C) focal necrosis with moderate inflammatory cell infiltration (score 3), and (D) severe glial cell and macrophage infiltration, and rarefaction of the neuropil in extensive necrotic foci (score 4). (E) The total pathological scores for different mouse brain areas were determined as described in the Materials and Methods (ten symptomatic and seven asymptomatic mice). *p < 0.05 and **p < 0.01 (unpaired Student's t-test). (F) After DNA extraction from N. caninum-infected mouse brain samples (four symptomatic and two asymptomatic mice) and paraffin-embedded brain tissues, including the medulla oblongata and cerebellum (ten symptomatic and seven asymptomatic mice), parasite numbers were quantified by real-time PCR using primers specific for the N. caninum Nc5 gene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300462&req=5

f2: Histopathological lesions and parasite distributions in different areas of N. caninum-infected mouse brains.(A–D) Histopathological lesions in mouse brains infected with N. caninum (n = 17). To estimate the severity of the histopathological lesions, the lesions were scored as follows: (A) localized perivascular cuff (score 1), (B) local gliosis (score 2), (C) focal necrosis with moderate inflammatory cell infiltration (score 3), and (D) severe glial cell and macrophage infiltration, and rarefaction of the neuropil in extensive necrotic foci (score 4). (E) The total pathological scores for different mouse brain areas were determined as described in the Materials and Methods (ten symptomatic and seven asymptomatic mice). *p < 0.05 and **p < 0.01 (unpaired Student's t-test). (F) After DNA extraction from N. caninum-infected mouse brain samples (four symptomatic and two asymptomatic mice) and paraffin-embedded brain tissues, including the medulla oblongata and cerebellum (ten symptomatic and seven asymptomatic mice), parasite numbers were quantified by real-time PCR using primers specific for the N. caninum Nc5 gene.
Mentions: Pathological severity was evaluated in 17 mice, and 10 of the 17 mice showed clinical signs of neosporosis including febrile responses and leg paralysis 39 days after infection (See Figure 1A). Seven of 10 symptomatic mice showed neurological signs, including circling motion, head tilting, and leg paralysis. We analyzed the nine area of brain histopathologically and for the quantification of parasite load. Histopathological lesions, including perivascular cuff, mononuclear cellular meningitis, glial cell activation, and focal necrosis, were observed in the brains of all 17 mice, which are similar to the lesions found in dogs891415. Each focal lesion was scored for severity using a scale from 1 to 4 (See Figure 2A–D). The total pathological scores for all areas in the brain are shown in Figure 2E. The total scores for the frontal lobe and medulla oblongata were significantly higher in the symptomatic mice than in the asymptomatic mice. Although there were no significant differences between the symptomatic and asymptomatic mice in the cerebellum, two symptomatic mice showed very high scores.

Bottom Line: A GOstat analysis predicted that the upregulated genes were involved in the host immune response.Genes whose expression correlated positively and negatively with parasite numbers were involved in the host immune response, and neuronal morphogenesis and lipid metabolic processes, respectively.These results suggest that changes in the gene expression profile associated with neuronal functions as well as immune responses can contribute to the pathogenesis in N. caninum-infected animals.

View Article: PubMed Central - PubMed

Affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, Japan.

ABSTRACT
Neospora caninum is a protozoan parasite that causes neurological disorders in dogs and cattle. It can cause nonsuppurative meningoencephalitis and a variety of neuronal symptoms are observed, particularly in dogs. However, the pathogenic mechanism, including the relationship between the parasite distribution and the clinical signs, is unclear. In this study, to understand the pathogenic mechanism of neosporosis, parasite distribution and lesions were assessed in the brain of mice infected with N. caninum (strain Nc-1). Host gene expression was also analyzed with RNA sequencing (RNA-Seq). The histopathological lesions in the frontal lobe and the medulla oblongata were significantly more severe in symptomatic mice than in asymptomatic mice, although no association between the severity of the lesions and parasite numbers was found. In infected mice, the expression of 772 mouse brain genes was upregulated. A GOstat analysis predicted that the upregulated genes were involved in the host immune response. Genes whose expression correlated positively and negatively with parasite numbers were involved in the host immune response, and neuronal morphogenesis and lipid metabolic processes, respectively. These results suggest that changes in the gene expression profile associated with neuronal functions as well as immune responses can contribute to the pathogenesis in N. caninum-infected animals.

Show MeSH
Related in: MedlinePlus