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Altered machinery of protein synthesis is region- and stage-dependent and is associated with α-synuclein oligomers in Parkinson's disease.

Garcia-Esparcia P, Hernández-Ortega K, Koneti A, Gil L, Delgado-Morales R, Castaño E, Carmona M, Ferrer I - Acta Neuropathol Commun (2015)

Bottom Line: No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6.Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen.This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain.

ABSTRACT

Introduction: Parkinson's disease (PD) is characterized by the accumulation of abnormal α-synuclein in selected regions of the brain following a gradient of severity with disease progression. Whether this is accompanied by globally altered protein synthesis is poorly documented. The present study was carried out in PD stages 1-6 of Braak and middle-aged (MA) individuals without alterations in brain in the substantia nigra, frontal cortex area 8, angular gyrus, precuneus and putamen.

Results: Reduced mRNA expression of nucleolar proteins nucleolin (NCL), nucleophosmin (NPM1), nucleoplasmin 3 (NPM3) and upstream binding transcription factor (UBF), decreased NPM1 but not NPM3 nucleolar protein immunostaining in remaining neurons; diminished 18S rRNA, 28S rRNA; reduced expression of several mRNAs encoding ribosomal protein (RP) subunits; and altered protein levels of initiation factor eIF3 and elongation factor eEF2 of protein synthesis was found in the substantia nigra in PD along with disease progression. Although many of these changes can be related to neuron loss in the substantia nigra, selective alteration of certain factors indicates variable degree of vulnerability of mRNAs, rRNAs and proteins in degenerating sustantia nigra. NPM1 mRNA and 18S rRNA was increased in the frontal cortex area 8 at stage 5-6; modifications were less marked and region-dependent in the angular gyrus and precuneus. Several RPs were abnormally regulated in the frontal cortex area 8 and precuneus, but only one RP in the angular gyrus, in PD. Altered levels of eIF3 and eIF1, and decrease eEF1A and eEF2 protein levels were observed in the frontal cortex in PD. No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6. These observations further indicate marked region-dependent and stage-dependent alterations in the cerebral cortex in PD. Altered solubility and α-synuclein oligomer formation, assessed in total homogenate fractions blotted with anti-α-synuclein oligomer-specific antibody, was demonstrated in the substantia nigra and frontal cortex, but not in the putamen, in PD. Dramatic increase in α-synuclein oligomers was also seen in fluorescent-activated cell sorter (FACS)-isolated nuclei in the frontal cortex in PD.

Conclusions: Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen. This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen.

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Altered expression levels of rRNA28S and rRNA18S in substantia nigra, frontal cortex area 8, angular gyrus, precuneus, and putamen in middle-aged (MA) and PD as determined by TaqMan PCR assays using GUS-β for normalization. Student’s t test *p < 0.05, **p < 0.01 and ***p < 0.001
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Fig2: Altered expression levels of rRNA28S and rRNA18S in substantia nigra, frontal cortex area 8, angular gyrus, precuneus, and putamen in middle-aged (MA) and PD as determined by TaqMan PCR assays using GUS-β for normalization. Student’s t test *p < 0.05, **p < 0.01 and ***p < 0.001

Mentions: In the substantia nigra, 18S rRNA levels were significantly reduced at stages 3–4 (p < 0.01), as were 28S rRNA and 18S rRNA levels at stages 5–6 (p < 0.05 and p < 0.001, respectively) (Fig. 2). Therefore, differences along disease progression were seen between stages 1–2 and 3–6 (Additional file 4: Table S4).Fig. 2


Altered machinery of protein synthesis is region- and stage-dependent and is associated with α-synuclein oligomers in Parkinson's disease.

Garcia-Esparcia P, Hernández-Ortega K, Koneti A, Gil L, Delgado-Morales R, Castaño E, Carmona M, Ferrer I - Acta Neuropathol Commun (2015)

Altered expression levels of rRNA28S and rRNA18S in substantia nigra, frontal cortex area 8, angular gyrus, precuneus, and putamen in middle-aged (MA) and PD as determined by TaqMan PCR assays using GUS-β for normalization. Student’s t test *p < 0.05, **p < 0.01 and ***p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4666041&req=5

Fig2: Altered expression levels of rRNA28S and rRNA18S in substantia nigra, frontal cortex area 8, angular gyrus, precuneus, and putamen in middle-aged (MA) and PD as determined by TaqMan PCR assays using GUS-β for normalization. Student’s t test *p < 0.05, **p < 0.01 and ***p < 0.001
Mentions: In the substantia nigra, 18S rRNA levels were significantly reduced at stages 3–4 (p < 0.01), as were 28S rRNA and 18S rRNA levels at stages 5–6 (p < 0.05 and p < 0.001, respectively) (Fig. 2). Therefore, differences along disease progression were seen between stages 1–2 and 3–6 (Additional file 4: Table S4).Fig. 2

Bottom Line: No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6.Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen.This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat; Biomedical Research Center of Neurodegenerative Diseases (CIBERNED), Barcelona, Spain.

ABSTRACT

Introduction: Parkinson's disease (PD) is characterized by the accumulation of abnormal α-synuclein in selected regions of the brain following a gradient of severity with disease progression. Whether this is accompanied by globally altered protein synthesis is poorly documented. The present study was carried out in PD stages 1-6 of Braak and middle-aged (MA) individuals without alterations in brain in the substantia nigra, frontal cortex area 8, angular gyrus, precuneus and putamen.

Results: Reduced mRNA expression of nucleolar proteins nucleolin (NCL), nucleophosmin (NPM1), nucleoplasmin 3 (NPM3) and upstream binding transcription factor (UBF), decreased NPM1 but not NPM3 nucleolar protein immunostaining in remaining neurons; diminished 18S rRNA, 28S rRNA; reduced expression of several mRNAs encoding ribosomal protein (RP) subunits; and altered protein levels of initiation factor eIF3 and elongation factor eEF2 of protein synthesis was found in the substantia nigra in PD along with disease progression. Although many of these changes can be related to neuron loss in the substantia nigra, selective alteration of certain factors indicates variable degree of vulnerability of mRNAs, rRNAs and proteins in degenerating sustantia nigra. NPM1 mRNA and 18S rRNA was increased in the frontal cortex area 8 at stage 5-6; modifications were less marked and region-dependent in the angular gyrus and precuneus. Several RPs were abnormally regulated in the frontal cortex area 8 and precuneus, but only one RP in the angular gyrus, in PD. Altered levels of eIF3 and eIF1, and decrease eEF1A and eEF2 protein levels were observed in the frontal cortex in PD. No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6. These observations further indicate marked region-dependent and stage-dependent alterations in the cerebral cortex in PD. Altered solubility and α-synuclein oligomer formation, assessed in total homogenate fractions blotted with anti-α-synuclein oligomer-specific antibody, was demonstrated in the substantia nigra and frontal cortex, but not in the putamen, in PD. Dramatic increase in α-synuclein oligomers was also seen in fluorescent-activated cell sorter (FACS)-isolated nuclei in the frontal cortex in PD.

Conclusions: Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen. This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen.

Show MeSH
Related in: MedlinePlus