Figure 7: Stable expression of PK2 protects against MPP+-mediated mitochondrial dysfunction and promotes mitochondrial biogenesis. | Nature Communications

Figure 7: Stable expression of PK2 protects against MPP+-mediated mitochondrial dysfunction and promotes mitochondrial biogenesis.

From: Prokineticin-2 upregulation during neuronal injury mediates a compensatory protective response against dopaminergic neuronal degeneration

Figure 7

(a-d) Reduced mitochondrial fragmentation in PK2-overexpressing cells. Mitochondrial fragmentation was visualized using MitoTracker Red in vector and PK2-overexpressing cells treated with MPP+ (300 μM) for 16 h. Scale bar, 10 μm. Reduced mitochondrial circularity (b), solidity (c) and increased mitochondrial length (d) were evident in cells overexpressing PK2 (Student’s t-test with n=3; NS, non-significant, P value=0.0767 in c). (e) Increased mitochondrial area in PK2-overexpressing cells. Mitochondrial area was measured by thresholding the MitoTracker Red images to compare with the total area of the cell. PK2-overexpressing cells had significantly more mitochondrial area/total cell area compared with vector cells (Student’s t-test with n=6–7). (f) Overexpression of PK2 increased ATP levels. PK2-overexpressing and vector cells were exposed to 300 μM MPP+ for 16 h, and the amount of cellular ATP produced was measured using the Luminescent Cell Viability assay kit (one-way ANOVA with Bonferroni post-test comparison and n=4). (g–k) Overexpression of PK2 upregulated mitochondrial biogenesis pathways. Real-time qPCR analysis of Bcl-2 (g) (Student’s t-test with n=3), PGC-1α (h) (one-way ANOVA with Bonferroni post-test comparison and n=3) and TFAM (i) (one-way ANOVA with Bonferroni post-test comparison and n=3–6) shows increased mRNA expression of Bcl-2, PGC-1α and TFAM in PK2-overexpressing cells compared with vector control cells 24 h post MPP+ (300 μM) treatment. Increased TFAM and TOM20 protein levels were found in PK2 cells compared with vector cells 24 h post MPP+ (300 μM) (j). Analysis of mitochondrial ND1 as a marker of mitochondrial DNA content shows increased mitochondrial DNA copy number (k) in PK2-overexpressing cells compared with vector control cells exposed to vehicle or 300 μM MPP+ for 24 h (one-way ANOVA with Bonferroni post-test comparison and n=6). Data represented by group mean±s.e.m. (*P<0.05, **P<0.01 and ***P<0.001, relative to relevant control or MPP+-treated groups).

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