2-Deoxy-D-glucose couples mitochondrial DNA replication with mitochondrial fitness and promotes the selection of wild-type over mutant mitochondrial DNA

Abstract

Pathological variants of human mitochondrial DNA (mtDNA) typically co-exist with wild-type molecules, but the factors driving the selection of each are not understood. Because mitochondrial fitness does not favour the propagation of functional mtDNAs in disease states, we sought to create conditions where it would be advantageous. Glucose and glutamine consumption are increased in mtDNA dysfunction, and so we targeted the use of both in cells carrying the pathogenic m.3243A>G variant with 2-Deoxy-D-glucose (2DG), or the related 5-thioglucose. Here, we show that both compounds selected wild-type over mutant mtDNA, restoring mtDNA expression and respiration. Mechanistically, 2DG selectively inhibits the replication of mutant mtDNA; and glutamine is the key target metabolite, as its withdrawal, too, suppresses mtDNA synthesis in mutant cells. Additionally, by restricting glucose utilization, 2DG supports functional mtDNAs, as glucose-fuelled respiration is critical for mtDNA replication in control cells, when glucose and glutamine are scarce. Hence, we demonstrate that mitochondrial fitness dictates metabolite preference for mtDNA replication; consequently, interventions that restrict metabolite availability can suppress pathological mtDNAs, by coupling mitochondrial fitness and replication.

2 deoxy-D-glucose augments the mitochondrial respiratory chain in heart

“…2DG restricts glucose consumption by inhibiting glycolysis, and in cultured cells curtailed glycolytic ATP production can be compensated by increased respiration (e.g. 12 ). The elevated mitochondrial respiratory chain proteome (Tables 1 and 2 , and Fig.…”

“…That 2DG is effective in vivo as well as in vitro boosts its prospects for clinical development. The therapeutic potential of 2DG extends from viruses 3 – 6 to cancer 2 , and it holds considerable promise for autosomal dominant polycystic disease (ADPKD) and some mitochondrial DNA diseases 12 , 17 . While these disorders have different features, the expectation is that all will benefit from a switch from glycolytic to mitochondrial ATP production.…”

“…Thus, decreasing glycolysis and augmenting mitochondrial function could be beneficial to tackle the disease. As 2DG achieves both these effects in cultured cells 12 we sought to determine whether this occurred in vivo in the heart, which could explain its reported anti-SARS.CoV-2 effects.…”

T cell differentiation drives the negative selection of pathogenic mtDNA variants

“…This is consistent with observations in m.3243A>G patient fibroblasts where restricting access to glucose and glutamine forces a reliance on pyruvate as a substrate, driving positive selection for wild-type and negative selection against variant mtDNA molecules(43). This selection is likely to be the result of selective depolarisation of mitochondria containing variant mtDNA, inhibiting the replication of variant mtDNA molecules and increasing wild-type mtDNA replication (43). In T cells, aged mitochondria are asymmetrically segregated into daughter cells with higher levels of autophagy, mitochondrial clearance and selfrenewal upon T cell activation-related cell division (42).…”

AKAP1 contributes to impaired mtDNA replication and mitochondrial dysfunction in podocytes of diabetic kidney disease

“…Mitochondrial DNA (mtDNA) is independent of nuclear DNA and encodes subunits involved in the mitochondrial respiratory chain, which mediates to proceed oxidative phosphorylation (OXPHOS), including ND1-6, ND4L, COX I-III, cyt-b, ATPase6 and ATPase8 [6]. mtDNA replication is closely related to mitochondrial metabolism [7,8]. Mitochondrial transcription factor A (TFAM), which is located in mitochondria, is necessary for mtDNA replication and mitochondrial biogenesis [9].…”