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Alterations in the cell cycle in the cerebellum of hyperbilirubinemic Gunn rat: a possible link with apoptosis?

Robert MC, Furlan G, Rosso N, Gambaro SE, Apitsionak F, Vianello E, Tiribelli C, Gazzin S - PLoS ONE (2013)

Bottom Line: The cerebellum of the hyperbilirubinemic Gunn rats exhibits an increased cell cycle arrest in the late G0/G1 phase (p < 0.001), characterized by a decrease in the protein expression of cyclin D1 (15%, p < 0.05), cyclin A/A1 (20 and 30%, p < 0.05 and 0.01, respectively) and cyclin dependent kinases2 (25%, p < 0.001).This was associated with a marked increase in the 18 kDa fragment of cyclin E (67%, p < 0.001) which amplifies the apoptotic pathway.These two phenomena might be intimately connected.

View Article: PubMed Central - PubMed

Affiliation: Fondazione Italiana Fegato (Italian Liver Foundation, Centro Studi Fegato), Trieste, Italy.

ABSTRACT
Severe hyperbilirubinemia causes neurological damage both in humans and rodents. The hyperbilirubinemic Gunn rat shows a marked cerebellar hypoplasia. More recently bilirubin ability to arrest the cell cycle progression in vascular smooth muscle, tumour cells, and, more importantly, cultured neurons has been demonstrated. However, the involvement of cell cycle perturbation in the development of cerebellar hypoplasia was never investigated before. We explored the effect of sustained spontaneous hyperbilirubinemia on cell cycle progression and apoptosis in whole cerebella dissected from 9 day old Gunn rat by Real Time PCR, Western blot and FACS analysis. The cerebellum of the hyperbilirubinemic Gunn rats exhibits an increased cell cycle arrest in the late G0/G1 phase (p < 0.001), characterized by a decrease in the protein expression of cyclin D1 (15%, p < 0.05), cyclin A/A1 (20 and 30%, p < 0.05 and 0.01, respectively) and cyclin dependent kinases2 (25%, p < 0.001). This was associated with a marked increase in the 18 kDa fragment of cyclin E (67%, p < 0.001) which amplifies the apoptotic pathway. In line with this was the increase of the cleaved form of Poly (ADP-ribose) polymerase (54%, p < 0.01) and active Caspase3 (two fold, p < 0.01). These data indicate that the characteristic cerebellar alteration in this developing brain structure of the hyperbilirubinemic Gunn rat may be partly due to cell cycle perturbation and apoptosis related to the high bilirubin concentration in cerebellar tissue mainly affecting granular cells. These two phenomena might be intimately connected.

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mRNA relative expression of Cyclin D1, Cyclin E1, Cyclin A, A1 and Cdk2.□ Normal homozygous JJ and ■ Hyperbilirubinemic homozygous jj Gunn rat. Data are expressed as mean ± SD. Statistical significance: ** p < 0.01.
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pone-0079073-g002: mRNA relative expression of Cyclin D1, Cyclin E1, Cyclin A, A1 and Cdk2.□ Normal homozygous JJ and ■ Hyperbilirubinemic homozygous jj Gunn rat. Data are expressed as mean ± SD. Statistical significance: ** p < 0.01.

Mentions: Selected Cyclins and cyclin-dependent kinase 2 (Cdk2) expression was followed as markers of bilirubin influence on the cell cycle, as previously reported by others [31–34]. The expression of Cyclin D1 (the first cyclin to be induced, regulating the G0 to S phase transition) and Cyclin A (S phase transition) mRNA was reduced (20% and 15%, respectively) in cerebella of jj rats, whereas Cyclin A1 and Cdk2 (forming active complexes with the Cyclins here studied) mRNA levels were comparable to controls. By contrast, the Cyclin E1 (G1 to S phase) mRNA level was increased by 45% (p < 0.01) in hyperbilirubinemic jj pups (Figure 2).


Alterations in the cell cycle in the cerebellum of hyperbilirubinemic Gunn rat: a possible link with apoptosis?

Robert MC, Furlan G, Rosso N, Gambaro SE, Apitsionak F, Vianello E, Tiribelli C, Gazzin S - PLoS ONE (2013)

mRNA relative expression of Cyclin D1, Cyclin E1, Cyclin A, A1 and Cdk2.□ Normal homozygous JJ and ■ Hyperbilirubinemic homozygous jj Gunn rat. Data are expressed as mean ± SD. Statistical significance: ** p < 0.01.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815147&req=5

pone-0079073-g002: mRNA relative expression of Cyclin D1, Cyclin E1, Cyclin A, A1 and Cdk2.□ Normal homozygous JJ and ■ Hyperbilirubinemic homozygous jj Gunn rat. Data are expressed as mean ± SD. Statistical significance: ** p < 0.01.
Mentions: Selected Cyclins and cyclin-dependent kinase 2 (Cdk2) expression was followed as markers of bilirubin influence on the cell cycle, as previously reported by others [31–34]. The expression of Cyclin D1 (the first cyclin to be induced, regulating the G0 to S phase transition) and Cyclin A (S phase transition) mRNA was reduced (20% and 15%, respectively) in cerebella of jj rats, whereas Cyclin A1 and Cdk2 (forming active complexes with the Cyclins here studied) mRNA levels were comparable to controls. By contrast, the Cyclin E1 (G1 to S phase) mRNA level was increased by 45% (p < 0.01) in hyperbilirubinemic jj pups (Figure 2).

Bottom Line: The cerebellum of the hyperbilirubinemic Gunn rats exhibits an increased cell cycle arrest in the late G0/G1 phase (p < 0.001), characterized by a decrease in the protein expression of cyclin D1 (15%, p < 0.05), cyclin A/A1 (20 and 30%, p < 0.05 and 0.01, respectively) and cyclin dependent kinases2 (25%, p < 0.001).This was associated with a marked increase in the 18 kDa fragment of cyclin E (67%, p < 0.001) which amplifies the apoptotic pathway.These two phenomena might be intimately connected.

View Article: PubMed Central - PubMed

Affiliation: Fondazione Italiana Fegato (Italian Liver Foundation, Centro Studi Fegato), Trieste, Italy.

ABSTRACT
Severe hyperbilirubinemia causes neurological damage both in humans and rodents. The hyperbilirubinemic Gunn rat shows a marked cerebellar hypoplasia. More recently bilirubin ability to arrest the cell cycle progression in vascular smooth muscle, tumour cells, and, more importantly, cultured neurons has been demonstrated. However, the involvement of cell cycle perturbation in the development of cerebellar hypoplasia was never investigated before. We explored the effect of sustained spontaneous hyperbilirubinemia on cell cycle progression and apoptosis in whole cerebella dissected from 9 day old Gunn rat by Real Time PCR, Western blot and FACS analysis. The cerebellum of the hyperbilirubinemic Gunn rats exhibits an increased cell cycle arrest in the late G0/G1 phase (p < 0.001), characterized by a decrease in the protein expression of cyclin D1 (15%, p < 0.05), cyclin A/A1 (20 and 30%, p < 0.05 and 0.01, respectively) and cyclin dependent kinases2 (25%, p < 0.001). This was associated with a marked increase in the 18 kDa fragment of cyclin E (67%, p < 0.001) which amplifies the apoptotic pathway. In line with this was the increase of the cleaved form of Poly (ADP-ribose) polymerase (54%, p < 0.01) and active Caspase3 (two fold, p < 0.01). These data indicate that the characteristic cerebellar alteration in this developing brain structure of the hyperbilirubinemic Gunn rat may be partly due to cell cycle perturbation and apoptosis related to the high bilirubin concentration in cerebellar tissue mainly affecting granular cells. These two phenomena might be intimately connected.

Show MeSH
Related in: MedlinePlus