Limits...
A lympho-follicular microenvironment is required for pathological prion protein deposition in chronically inflamed tissues from scrapie-affected sheep.

Maestrale C, Di Guardo G, Cancedda MG, Marruchella G, Masia M, Sechi S, Macciocu S, Santucciu C, Petruzzi M, Ligios C - PLoS ONE (2013)

Bottom Line: We demonstrated that ectopic PrP(Sc) deposition occurs exclusively in the context of lymphofollicular inflammatory sites, inside newly formed and well-organized lymphoid follicles harboring follicular dendritic cells.A significantly more consistent expression of lymphotoxin α and β mRNA was detected in lymphofollicular inflammation compared to the other two types, with lymphotoxin α and β signaling new lymphoid follicles' formation and, likely, the occurrence of ectopic PrP(Sc) deposition inside them.Our findings suggest that, in sheep co-affected by scrapie and chronic inflammatory conditions, only newly formed lymphoid follicles provide a suitable micro-environment that supports the scrapie agent's replication in inflammatory sites, with an increased risk of prion shedding through body secretions/excretions.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Sanità Animale, Istituto Zooprofilattico Sperimentale della Sardegna, Sassari, Italy.

ABSTRACT
In sheep scrapie, pathological prion protein (PrP(Sc)) deposition occurs in the lymphoreticular and central nervous systems. We investigated PrP(Sc) distribution in scrapie-affected sheep showing simultaneous evidence of chronic lymphofollicular, lymphoproliferative/non-lymphofollicular, and/or granulomatous inflammations in their mammary gland, lung, and ileum. To do this, PrP(Sc) detection was carried out via immunohistochemistry and Western Blotting techniques, as well as through inflammatory cell immunophenotyping. Expression studies of gene coding for biological factors modulating the host's inflammatory response were also carried out. We demonstrated that ectopic PrP(Sc) deposition occurs exclusively in the context of lymphofollicular inflammatory sites, inside newly formed and well-organized lymphoid follicles harboring follicular dendritic cells. On the contrary, no PrP(Sc) deposition was detected in granulomas, even when they were closely located to newly formed lymphoid follicles. A significantly more consistent expression of lymphotoxin α and β mRNA was detected in lymphofollicular inflammation compared to the other two types, with lymphotoxin α and β signaling new lymphoid follicles' formation and, likely, the occurrence of ectopic PrP(Sc) deposition inside them. Our findings suggest that, in sheep co-affected by scrapie and chronic inflammatory conditions, only newly formed lymphoid follicles provide a suitable micro-environment that supports the scrapie agent's replication in inflammatory sites, with an increased risk of prion shedding through body secretions/excretions.

Show MeSH

Related in: MedlinePlus

qRT-PCR expression of PrP gene in sheep mammary glands.Transcript levels are shown in mammary glands with lymphofollicular, lymphoproliferative/non-lymphofollicular, and granulomatous mastitis, as well as in histologically and microbiologically healthy ovine mammary glands (Groups A, B, C, and D, respectively, as described in “Materials and Methods”). Transcripts were normalized to housekeeping sheep 18S gene level. Differences in PrP gene expression levels were calculated as fold changes in transcripts between the mammary gland tissue samples under study versus one histologically and microbiologically healthy sheep mammary gland, which was used as the reference value. The box represents the 25th to 75th quartile, the whiskers represent the range, and the horizontal line in the box is the median. White dots beyond the whiskers indicate outliers. The sample values were normalized to housekeeping sheep 18S gene level.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3643908&req=5

pone-0062830-g007: qRT-PCR expression of PrP gene in sheep mammary glands.Transcript levels are shown in mammary glands with lymphofollicular, lymphoproliferative/non-lymphofollicular, and granulomatous mastitis, as well as in histologically and microbiologically healthy ovine mammary glands (Groups A, B, C, and D, respectively, as described in “Materials and Methods”). Transcripts were normalized to housekeeping sheep 18S gene level. Differences in PrP gene expression levels were calculated as fold changes in transcripts between the mammary gland tissue samples under study versus one histologically and microbiologically healthy sheep mammary gland, which was used as the reference value. The box represents the 25th to 75th quartile, the whiskers represent the range, and the horizontal line in the box is the median. White dots beyond the whiskers indicate outliers. The sample values were normalized to housekeeping sheep 18S gene level.

Mentions: For all the cytokines, chemokines, adhesion molecule, and receptors under study (with the exception of LTβR, which appeared to be similarly expressed in all groups), we observed significantly increased (P-values <0.05) levels of transcription in all mammary glands with lymphofollicular mastitis (Group A) compared to healthy mammary glands. In addition, mRNA expression was significantly more elevated for LTα, (P-values = 0.003 and 0.001), LTβ (P-values = 0.001 and 0.000), CCL19 (P-values = 0.016 and 0.036), CCR7 (P-values = 0.004 and 0.009), CXCR5 (P-value = 0.000), as well as for LYVE-1 (P-values = 0.039 and 0.33) in Group A versus Groups B, C, and D, respectively (Table 3). As far as Group C sheep are concerned, we observed that CXCL12 and VCAM-1 were significantly up-regulated in mammary glands affected by granulomatous mastitis as compared to healthy mammary glands (P-values = 0.005 and 0.022, respectively), demonstrating that some molecular determinants may still play an important role independently from inflammatory lesions’ morphopathological development. Nevertheless, the gene expression levels appeared to be similar among sheep with granulomatous and lymphoproliferative/non lymphofollicular mastitis (Table 3; Figure 6). Furthermore, PrP gene transcript levels were statistically higher in the mammary glands affected by granulomatous mastitis (P-values <0.001) in comparison to the other inflamed or healthy mammary glands (Figure 7). All details regarding gene expression quantification are shown in Table 3 and Figures 6–7.


A lympho-follicular microenvironment is required for pathological prion protein deposition in chronically inflamed tissues from scrapie-affected sheep.

Maestrale C, Di Guardo G, Cancedda MG, Marruchella G, Masia M, Sechi S, Macciocu S, Santucciu C, Petruzzi M, Ligios C - PLoS ONE (2013)

qRT-PCR expression of PrP gene in sheep mammary glands.Transcript levels are shown in mammary glands with lymphofollicular, lymphoproliferative/non-lymphofollicular, and granulomatous mastitis, as well as in histologically and microbiologically healthy ovine mammary glands (Groups A, B, C, and D, respectively, as described in “Materials and Methods”). Transcripts were normalized to housekeeping sheep 18S gene level. Differences in PrP gene expression levels were calculated as fold changes in transcripts between the mammary gland tissue samples under study versus one histologically and microbiologically healthy sheep mammary gland, which was used as the reference value. The box represents the 25th to 75th quartile, the whiskers represent the range, and the horizontal line in the box is the median. White dots beyond the whiskers indicate outliers. The sample values were normalized to housekeeping sheep 18S gene level.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643908&req=5

pone-0062830-g007: qRT-PCR expression of PrP gene in sheep mammary glands.Transcript levels are shown in mammary glands with lymphofollicular, lymphoproliferative/non-lymphofollicular, and granulomatous mastitis, as well as in histologically and microbiologically healthy ovine mammary glands (Groups A, B, C, and D, respectively, as described in “Materials and Methods”). Transcripts were normalized to housekeeping sheep 18S gene level. Differences in PrP gene expression levels were calculated as fold changes in transcripts between the mammary gland tissue samples under study versus one histologically and microbiologically healthy sheep mammary gland, which was used as the reference value. The box represents the 25th to 75th quartile, the whiskers represent the range, and the horizontal line in the box is the median. White dots beyond the whiskers indicate outliers. The sample values were normalized to housekeeping sheep 18S gene level.
Mentions: For all the cytokines, chemokines, adhesion molecule, and receptors under study (with the exception of LTβR, which appeared to be similarly expressed in all groups), we observed significantly increased (P-values <0.05) levels of transcription in all mammary glands with lymphofollicular mastitis (Group A) compared to healthy mammary glands. In addition, mRNA expression was significantly more elevated for LTα, (P-values = 0.003 and 0.001), LTβ (P-values = 0.001 and 0.000), CCL19 (P-values = 0.016 and 0.036), CCR7 (P-values = 0.004 and 0.009), CXCR5 (P-value = 0.000), as well as for LYVE-1 (P-values = 0.039 and 0.33) in Group A versus Groups B, C, and D, respectively (Table 3). As far as Group C sheep are concerned, we observed that CXCL12 and VCAM-1 were significantly up-regulated in mammary glands affected by granulomatous mastitis as compared to healthy mammary glands (P-values = 0.005 and 0.022, respectively), demonstrating that some molecular determinants may still play an important role independently from inflammatory lesions’ morphopathological development. Nevertheless, the gene expression levels appeared to be similar among sheep with granulomatous and lymphoproliferative/non lymphofollicular mastitis (Table 3; Figure 6). Furthermore, PrP gene transcript levels were statistically higher in the mammary glands affected by granulomatous mastitis (P-values <0.001) in comparison to the other inflamed or healthy mammary glands (Figure 7). All details regarding gene expression quantification are shown in Table 3 and Figures 6–7.

Bottom Line: We demonstrated that ectopic PrP(Sc) deposition occurs exclusively in the context of lymphofollicular inflammatory sites, inside newly formed and well-organized lymphoid follicles harboring follicular dendritic cells.A significantly more consistent expression of lymphotoxin α and β mRNA was detected in lymphofollicular inflammation compared to the other two types, with lymphotoxin α and β signaling new lymphoid follicles' formation and, likely, the occurrence of ectopic PrP(Sc) deposition inside them.Our findings suggest that, in sheep co-affected by scrapie and chronic inflammatory conditions, only newly formed lymphoid follicles provide a suitable micro-environment that supports the scrapie agent's replication in inflammatory sites, with an increased risk of prion shedding through body secretions/excretions.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Sanità Animale, Istituto Zooprofilattico Sperimentale della Sardegna, Sassari, Italy.

ABSTRACT
In sheep scrapie, pathological prion protein (PrP(Sc)) deposition occurs in the lymphoreticular and central nervous systems. We investigated PrP(Sc) distribution in scrapie-affected sheep showing simultaneous evidence of chronic lymphofollicular, lymphoproliferative/non-lymphofollicular, and/or granulomatous inflammations in their mammary gland, lung, and ileum. To do this, PrP(Sc) detection was carried out via immunohistochemistry and Western Blotting techniques, as well as through inflammatory cell immunophenotyping. Expression studies of gene coding for biological factors modulating the host's inflammatory response were also carried out. We demonstrated that ectopic PrP(Sc) deposition occurs exclusively in the context of lymphofollicular inflammatory sites, inside newly formed and well-organized lymphoid follicles harboring follicular dendritic cells. On the contrary, no PrP(Sc) deposition was detected in granulomas, even when they were closely located to newly formed lymphoid follicles. A significantly more consistent expression of lymphotoxin α and β mRNA was detected in lymphofollicular inflammation compared to the other two types, with lymphotoxin α and β signaling new lymphoid follicles' formation and, likely, the occurrence of ectopic PrP(Sc) deposition inside them. Our findings suggest that, in sheep co-affected by scrapie and chronic inflammatory conditions, only newly formed lymphoid follicles provide a suitable micro-environment that supports the scrapie agent's replication in inflammatory sites, with an increased risk of prion shedding through body secretions/excretions.

Show MeSH
Related in: MedlinePlus