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Dysregulated expression of death, stress and mitochondrion related genes in the sciatic nerve of presymptomatic SOD1(G93A) mouse model of Amyotrophic Lateral Sclerosis.

Alves CJ, Maximino JR, Chadi G - Front Cell Neurosci (2015)

Bottom Line: Despite the involvement of Schwann cells in early neuromuscular disruption in ALS, detailed molecular events of a dying-back triggering are unknown.DAVID demonstrated the deregulated genes related to death, stress and mitochondrion, which allowed the identification of Cell cycle, ErbB signaling, Tryptophan metabolism and Rig-I-like receptor signaling as the most representative KEGG pathways.The protein-protein interaction networks based upon deregulated genes have identified the top hubs (TRAF2, H2AFX, E2F1, FOXO3, MSH2, NGFR, TGFBR1) and bottlenecks (TRAF2, E2F1, CDKN1B, TWIST1, FOXO3).

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Neuroregeneration Center, University of São Paulo School of Medicine São Paulo, Brazil.

ABSTRACT
Schwann cells are the main source of paracrine support to motor neurons. Oxidative stress and mitochondrial dysfunction have been correlated to motor neuron death in Amyotrophic Lateral Sclerosis (ALS). Despite the involvement of Schwann cells in early neuromuscular disruption in ALS, detailed molecular events of a dying-back triggering are unknown. Sciatic nerves of presymptomatic (60-day-old) SOD1(G93A) mice were submitted to a high-density oligonucleotide microarray analysis. DAVID demonstrated the deregulated genes related to death, stress and mitochondrion, which allowed the identification of Cell cycle, ErbB signaling, Tryptophan metabolism and Rig-I-like receptor signaling as the most representative KEGG pathways. The protein-protein interaction networks based upon deregulated genes have identified the top hubs (TRAF2, H2AFX, E2F1, FOXO3, MSH2, NGFR, TGFBR1) and bottlenecks (TRAF2, E2F1, CDKN1B, TWIST1, FOXO3). Schwann cells were enriched from the sciatic nerve of presymptomatic mice using flow cytometry cell sorting. qPCR showed the up regulated (Ngfr, Cdnkn1b, E2f1, Traf2 and Erbb3, H2afx, Cdkn1a, Hspa1, Prdx, Mapk10) and down-regulated (Foxo3, Mtor) genes in the enriched Schwann cells. In conclusion, molecular analyses in the presymptomatic sciatic nerve demonstrated the involvement of death, oxidative stress, and mitochondrial pathways in the Schwann cell non-autonomous mechanisms in the early stages of ALS.

No MeSH data available.


Related in: MedlinePlus

Histopathological analysis (A–J) and molecular evaluation of hSOD1G93A signal (B) in the sciatic nerve and Schwann cell samples of 60-day-old presymptomatic SOD1G93A and aged paired wild-type mice. Immunofluorescence staining of MAP2 (A,B; red), GAP-43 (C,D; green), S100 (E,F; green) and p75NGF (G,H; green) in the sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (B,D,F,H) and their wild-type controls (A,C,E,G). MAP2 and GAP-43 are markers of neuronal fibers; S100 and p75NGF are markers of Schwann cells. Cell nuclei were stained with DAPI (blue). The insert boxes in the bottom left of images show a higher magnification of the cell profiles. Methylene blue staining of Schwann cell myelin sheets of sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (J) and their wild-type controls (I) are also seen. Scale bars: 10 μm. Of note, the same staining pattern was observed for both genotypes (SOD1G93A and wild-type controls) for all cell markers and for the histological sections. Representative bands of PCR for specific gene markers of human SOD1G93A (hSOD1G93A) and actin b (Actb) in sciatic nerve (K) and Schwann cells enriched samples (L) obtained by flow cytometry sorting of SOD1G93A and wild-type control mice.
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Figure 2: Histopathological analysis (A–J) and molecular evaluation of hSOD1G93A signal (B) in the sciatic nerve and Schwann cell samples of 60-day-old presymptomatic SOD1G93A and aged paired wild-type mice. Immunofluorescence staining of MAP2 (A,B; red), GAP-43 (C,D; green), S100 (E,F; green) and p75NGF (G,H; green) in the sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (B,D,F,H) and their wild-type controls (A,C,E,G). MAP2 and GAP-43 are markers of neuronal fibers; S100 and p75NGF are markers of Schwann cells. Cell nuclei were stained with DAPI (blue). The insert boxes in the bottom left of images show a higher magnification of the cell profiles. Methylene blue staining of Schwann cell myelin sheets of sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (J) and their wild-type controls (I) are also seen. Scale bars: 10 μm. Of note, the same staining pattern was observed for both genotypes (SOD1G93A and wild-type controls) for all cell markers and for the histological sections. Representative bands of PCR for specific gene markers of human SOD1G93A (hSOD1G93A) and actin b (Actb) in sciatic nerve (K) and Schwann cells enriched samples (L) obtained by flow cytometry sorting of SOD1G93A and wild-type control mice.

Mentions: No qualitative changes were found regarding morphology of sciatic nerves of presymptomatic ALS mice compared to control at histopathological examination (Figures 2A–J). PCR analysis of sciatic nerve and Schwann cells enriched by flow cytometry showed the presence of hSOD1G93A in the SOD1G93A mice, but not in the wild-type controls (Figures 2K,L). Also, the flow cytometry sorting Schwann cells of ALS mice did not show morphological differences (cell size and cytoplasmic granules) compared to control mice (Figures 1C,D).


Dysregulated expression of death, stress and mitochondrion related genes in the sciatic nerve of presymptomatic SOD1(G93A) mouse model of Amyotrophic Lateral Sclerosis.

Alves CJ, Maximino JR, Chadi G - Front Cell Neurosci (2015)

Histopathological analysis (A–J) and molecular evaluation of hSOD1G93A signal (B) in the sciatic nerve and Schwann cell samples of 60-day-old presymptomatic SOD1G93A and aged paired wild-type mice. Immunofluorescence staining of MAP2 (A,B; red), GAP-43 (C,D; green), S100 (E,F; green) and p75NGF (G,H; green) in the sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (B,D,F,H) and their wild-type controls (A,C,E,G). MAP2 and GAP-43 are markers of neuronal fibers; S100 and p75NGF are markers of Schwann cells. Cell nuclei were stained with DAPI (blue). The insert boxes in the bottom left of images show a higher magnification of the cell profiles. Methylene blue staining of Schwann cell myelin sheets of sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (J) and their wild-type controls (I) are also seen. Scale bars: 10 μm. Of note, the same staining pattern was observed for both genotypes (SOD1G93A and wild-type controls) for all cell markers and for the histological sections. Representative bands of PCR for specific gene markers of human SOD1G93A (hSOD1G93A) and actin b (Actb) in sciatic nerve (K) and Schwann cells enriched samples (L) obtained by flow cytometry sorting of SOD1G93A and wild-type control mice.
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Figure 2: Histopathological analysis (A–J) and molecular evaluation of hSOD1G93A signal (B) in the sciatic nerve and Schwann cell samples of 60-day-old presymptomatic SOD1G93A and aged paired wild-type mice. Immunofluorescence staining of MAP2 (A,B; red), GAP-43 (C,D; green), S100 (E,F; green) and p75NGF (G,H; green) in the sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (B,D,F,H) and their wild-type controls (A,C,E,G). MAP2 and GAP-43 are markers of neuronal fibers; S100 and p75NGF are markers of Schwann cells. Cell nuclei were stained with DAPI (blue). The insert boxes in the bottom left of images show a higher magnification of the cell profiles. Methylene blue staining of Schwann cell myelin sheets of sciatic nerve of 60-day-old presymptomatic SOD1G93A mice (J) and their wild-type controls (I) are also seen. Scale bars: 10 μm. Of note, the same staining pattern was observed for both genotypes (SOD1G93A and wild-type controls) for all cell markers and for the histological sections. Representative bands of PCR for specific gene markers of human SOD1G93A (hSOD1G93A) and actin b (Actb) in sciatic nerve (K) and Schwann cells enriched samples (L) obtained by flow cytometry sorting of SOD1G93A and wild-type control mice.
Mentions: No qualitative changes were found regarding morphology of sciatic nerves of presymptomatic ALS mice compared to control at histopathological examination (Figures 2A–J). PCR analysis of sciatic nerve and Schwann cells enriched by flow cytometry showed the presence of hSOD1G93A in the SOD1G93A mice, but not in the wild-type controls (Figures 2K,L). Also, the flow cytometry sorting Schwann cells of ALS mice did not show morphological differences (cell size and cytoplasmic granules) compared to control mice (Figures 1C,D).

Bottom Line: Despite the involvement of Schwann cells in early neuromuscular disruption in ALS, detailed molecular events of a dying-back triggering are unknown.DAVID demonstrated the deregulated genes related to death, stress and mitochondrion, which allowed the identification of Cell cycle, ErbB signaling, Tryptophan metabolism and Rig-I-like receptor signaling as the most representative KEGG pathways.The protein-protein interaction networks based upon deregulated genes have identified the top hubs (TRAF2, H2AFX, E2F1, FOXO3, MSH2, NGFR, TGFBR1) and bottlenecks (TRAF2, E2F1, CDKN1B, TWIST1, FOXO3).

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Neuroregeneration Center, University of São Paulo School of Medicine São Paulo, Brazil.

ABSTRACT
Schwann cells are the main source of paracrine support to motor neurons. Oxidative stress and mitochondrial dysfunction have been correlated to motor neuron death in Amyotrophic Lateral Sclerosis (ALS). Despite the involvement of Schwann cells in early neuromuscular disruption in ALS, detailed molecular events of a dying-back triggering are unknown. Sciatic nerves of presymptomatic (60-day-old) SOD1(G93A) mice were submitted to a high-density oligonucleotide microarray analysis. DAVID demonstrated the deregulated genes related to death, stress and mitochondrion, which allowed the identification of Cell cycle, ErbB signaling, Tryptophan metabolism and Rig-I-like receptor signaling as the most representative KEGG pathways. The protein-protein interaction networks based upon deregulated genes have identified the top hubs (TRAF2, H2AFX, E2F1, FOXO3, MSH2, NGFR, TGFBR1) and bottlenecks (TRAF2, E2F1, CDKN1B, TWIST1, FOXO3). Schwann cells were enriched from the sciatic nerve of presymptomatic mice using flow cytometry cell sorting. qPCR showed the up regulated (Ngfr, Cdnkn1b, E2f1, Traf2 and Erbb3, H2afx, Cdkn1a, Hspa1, Prdx, Mapk10) and down-regulated (Foxo3, Mtor) genes in the enriched Schwann cells. In conclusion, molecular analyses in the presymptomatic sciatic nerve demonstrated the involvement of death, oxidative stress, and mitochondrial pathways in the Schwann cell non-autonomous mechanisms in the early stages of ALS.

No MeSH data available.


Related in: MedlinePlus