Methylene blue alleviates nuclear and mitochondrial abnormalities in progeria

Abstract

SummaryHutchinson–Gilford progeria syndrome (HGPS), a fatal premature aging disease, is caused by a single‐nucleotide mutation in the LMNA gene. Previous reports have focused on nuclear phenotypes in HGPS cells, yet the potential contribution of the mitochondria, a key player in normal aging, remains unclear. Using high‐resolution microscopy analysis, we demonstrated a significantly increased fraction of swollen and fragmented mitochondria and a marked reduction in mitochondrial mobility in HGPS fibroblast cells. Notably, the expression of PGC‐1α, a central regulator of mitochondrial biogenesis, was inhibited by progerin. To rescue mitochondrial defects, we treated HGPS cells with a mitochondrial‐targeting antioxidant methylene blue (MB). Our analysis indicated that MB treatment not only alleviated the mitochondrial defects but also rescued the hallmark nuclear abnormalities in HGPS cells. Additional analysis suggested that MB treatment released progerin from the nuclear membrane, rescued perinuclear heterochromatin loss and corrected misregulated gene expression in HGPS cells. Together, these results demonstrate a role of mitochondrial dysfunction in developing the premature aging phenotypes in HGPS cells and suggest MB as a promising therapeutic approach for HGPS.

Loss of H3K9me3 Correlates with ATM Activation and Histone H2AX Phosphorylation Deficiencies in Hutchinson-Gilford Progeria Syndrome

“…Primary HGPS human skin fibroblast cells that carry the classic 1824 C->T mutation (HGADFN167) and normal control cells (HGFDFN168, father of HGADFN167) were obtained from the Progeria Research Foundation (PRF) and cultured under conditions as previously described [33]. For passaging, cells were split at a ratio of 1:2 at 95% confluency.…”

“…Methylene blue treatment was conducted as previously described [33]. Briefly, MB was dissolved in PBS and added to growth medium at a final concentration of 100nM.…”

“…Finally, we show evidence supporting that the observed ATM inactivation is closely correlated with the loss of H3K9me3 in HGPS fibroblasts. Attempts to increase H3K9me3 through methylene blue (MB), an antioxidant which has been recently reported to remove progerin from the nuclear rim and rescue heterochromatin loss in HGPS [33], was able to restore H3K9me3, rescue the defects in ATM activation, gammaH2AX signal strength, and DDR in HGPS fibroblasts. These results suggest a novel connection between the two prominent phenotypes (H3K9me3 loss and DDR deficiency) and provide mechanistic insights underlying the complex phenotypes in HGPS cells.…”

Shared molecular and cellular mechanisms of premature ageing and ageing-associated diseases

“…4). Activation of PGC1α alleviates mitochondrial dysfunction and other ageing defects in fibroblasts from patients with HGPS 105 , although the beneficial effects of PCG1α activation in vivo appear to be tissue-specific and dependent on the duration and extent of activation 37 . Decreased PGC1α activity occurs in Alzheimer disease and Parkinson disease and is implicated in CKD-associated muscular dystrophy 110,119 .…”

“…In these mice, OXPHOS efficiency is reduced owing to the accumulation of mtDNA mutations, which causes accelerated ageing 104 . In HGPS, mitochondria are aberrantly swollen and fragmented 105 , and OXPHOS activity progressively decreases from an early age 106 . Wrn -null mice have enlarged mitochondria, increased accumulation of mtDNA mutations and increased ROS formation at the expense of ATP generation 107 .…”