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ABSTRACT: To explore possible relationships between mitochondrial DNA (mtDNA) polymorphism and the expression levels of stress-responder
nuclear genes we assembled five cybrid cell lines by repopulating 143B.TK− cells, depleted of their own mtDNA (Rho0 cells), with foreign mitochondria with different mtDNA sequences (lines H, J, T, U, X). We evaluated, at both basal and under
heat stress conditions, gene expression (mRNA) and intra-mitochondrial protein levels of HSP60 and HSP75, two key components
in cellular stress response. At basal conditions, the levels of HSP60 and HSP75 mRNA were lower in one cybrid (H) than in
the others (p = 0.005 and p = 0.001, respectively). Under stress conditions, the H line over-expressed both genes, so that the inter-cybrid difference
was abolished. Moreover, the HSP60 intra-mitochondrial protein levels differed among the cybrid lines (p = 0.001), with levels higher in H than in the other cybrid lines. On the whole, our results provide further experimental
evidence that mtDNA variability influences the cell response to stressful conditions by modulating components involved in
this response. Sentence summary of the article: the results reported in the present study provide important experimental evidence
that in human cells mtDNA variability is able to influence the cellular response to heat stress by modulating both the transcription
of genes involved in this response and their intra-mitochondrial protein levels.
Cell Stress and Chaperones 04/2012; 14(3):265-271. · 3.01 Impact Factor
