Scientists Reveal How the PARK7–PINK1 Protein Axis Controls Stem Cell Reprogramming

One of the most celebrated feats of modern biology is the ability to rewind an adult cell back into an embryonic-like state. Since induced pluripotent stem cells, or iPSCs, were first derived, researchers have harnessed them for disease modeling, drug screening, and the promise of regenerative therapies. Yet the process of reprogramming a somatic cell into a pluripotent one remains remarkably inefficient, and the molecular choreography that governs it is still only partly understood. A new study published in Cellular and Molecular Life Sciences by Emmanuel Osei Mensah, Ken Nishimura, and colleagues at the University of Tsukuba now adds a crucial piece to that puzzle, identifying a signaling axis between two proteins famous for their roles in Parkinson’s disease that quietly orchestrates the redox and metabolic upheaval required for a cell to become pluripotent.

The two proteins in question are PARK7, also known as DJ-1, and PINK1. Both are best known to the public through their connection to familial Parkinson’s disease, where loss-of-function mutations sensitize neurons to oxidative damage and mitochondrial dysfunction. In the new work, the Tsukuba team asked whether these same proteins do something entirely different in a very different cellular context: the dramatic transformation that occurs when mouse embryonic fibroblasts are pushed toward pluripotency by reprogramming factors. PARK7 is a multifunctional, redox-sensitive protein long implicated in buffering oxidative stress and modulating transcription, and earlier reports had suggested it could associate with the promoter of Nanog, a master gene of pluripotency, and even suppress reprogramming efficiency. That hint of an inhibitory role made PARK7 an intriguing suspect.

To test the idea, the researchers depleted Park7 in mouse embryonic fibroblasts undergoing reprogramming and monitored the emergence of Nanog-positive colonies, a standard readout of successful pluripotency induction. The result was striking: knocking down Park7 enhanced colony formation, with the effect most pronounced during the early phases of reprogramming. In other words, removing PARK7 made it easier for somatic cells to cross the initial barriers on the road to pluripotency. This positioned PARK7 not as a passive bystander but as an active regulator of the process, and it raised the obvious question of how a protein best known for antioxidant defense could, when removed, actually improve the efficiency of cellular rejuvenation.

The answer, it turns out, lies in reactive oxygen species. Reprogramming is metabolically traumatic: a cell that has spent its life burning glucose efficiently through mitochondrial oxidative phosphorylation must tear down and rebuild its entire energy economy, ultimately adopting the glycolytic, lactate-producing metabolism characteristic of embryonic stem cells. That transition is accompanied by bursts of reactive oxygen species, which at controlled levels act as signaling molecules that help drive the switch. Using paused iPSCs, a valuable experimental system in which cells are held in a partially reprogrammed state and can be interrogated in detail, the team showed that depleting Park7 increased both mitochondrial and cytosolic ROS, stabilized HIF-1α, the hypoxia-inducible transcription factor that commands the glycolytic program, promoted the expression of glycolytic genes, and upregulated pluripotency markers.

The causal chain became clear when the researchers added antioxidants to the culture. Antioxidant treatment substantially blunted all of these effects, indicating that the enhanced reprogramming phenotype seen upon Park7 loss was driven by ROS-mediated metabolic remodeling rather than by some unrelated function of the protein. In essence, PARK7 normally keeps a brake on ROS levels, and that brake, paradoxically, restrains the very oxidative signals that help push a cell toward pluripotency. When the brake is released, ROS rise, HIF-1α accumulates, glycolysis genes switch on, and the cell slides more readily into its new pluripotent identity. It is a vivid demonstration that in reprogramming, a little oxidative stress is not the enemy but an ally.

The study also uncovered a second, compensatory layer of redox regulation. The elevated ROS triggered by Park7 depletion activated NRF2, the master transcription factor of antioxidant defense, switching on NRF2-dependent antioxidant transcriptional programs. This reveals a built-in feedback loop: as ROS climb and drive metabolic remodeling, the cell simultaneously mounts a protective antioxidant response, presumably to keep the oxidative surge within tolerable limits. The interplay between these pro-signaling and protective arms of the redox system highlights how finely balanced the reprogramming environment must be, and it suggests that manipulating this balance could be a way to tune reprogramming efficiency in the laboratory.

Perhaps the most consequential discovery, however, concerns PINK1. The team found that Park7 depletion reduces the expression of Pink1, and that knocking down Pink1 phenocopies the loss of Park7, producing the same ROS elevation, metabolic shift, and pluripotency marker upregulation. Most tellingly, restoring wild-type PINK1 reversed the increase in pluripotency markers caused by Park7 loss. Together, these experiments establish PINK1 as the essential downstream mediator of PARK7 in this cascade. The two Parkinson’s-linked proteins, it appears, operate as a functional axis: PARK7 upstream, sustaining PINK1 expression, and PINK1 downstream, executing the ROS-suppressing and metabolic functions that keep reprogramming in check.

This PARK7–PINK1 axis is more than a curiosity of stem cell biology. It suggests that the same molecular machinery whose failure contributes to neurodegeneration also serves as a gatekeeper during the acquisition of pluripotency, coordinating three intertwined processes: suppression of reactive oxygen species, glycolytic metabolic remodeling, and the expression of pluripotency genes. For researchers trying to generate iPSCs more efficiently and more safely, the findings point to concrete levers. Modulating PARK7 or PINK1 activity, or carefully titrating ROS with antioxidants, could in principle shift cells along the reprogramming trajectory. At the same time, the work cautions that redox manipulation is a double-edged sword, since the NRF2 response shows the cell actively defending itself against the very signals that promote its transformation.

There are also broader implications for understanding disease. PARK7 and PINK1 are central figures in the mitochondrial quality control literature, and this study ties them to HIF-1α-driven metabolic switching and NRF2-mediated antioxidant transcription, linking several of the most important stress-response pathways in cell biology into a single regulatory circuit. Whether the axis operates similarly in human cells, and whether it influences the quality and genomic stability of the resulting iPSCs, are questions the field will now want to pursue. The experiments were conducted in mouse embryonic fibroblasts and paused iPSCs, so translating the mechanism to human reprogramming systems will be an essential next step.

What the study delivers today is a mechanistic framework with immediate experimental value. By showing that PARK7 restrains reprogramming primarily through PINK1-dependent control of ROS, the Tsukuba team has converted a long-standing puzzle about DJ-1’s role at the Nanog promoter into a coherent signaling pathway that connects redox balance, metabolism, and gene expression during one of biology’s most dramatic cellular transformations. As regenerative medicine moves closer to the clinic, understanding such gatekeepers, and learning when to release them and when to respect them, may prove as important as the reprogramming factors themselves. The full open-access study is available in Cellular and Molecular Life Sciences for readers who wish to explore the experimental details.

Subject of Research: The role of the PARK7–PINK1 axis in redox balance and metabolic remodeling during induced pluripotent stem cell reprogramming

Article Title: A PARK7–PINK1 axis coordinates redox balance and metabolic remodeling during somatic cell reprogramming

Article References: Mensah, E. O., Burramsetty, A. K., Kamata, H., Jiang, Z., Fukuda, A., Hisatake, K., & Nishimura, K. (2026). A PARK7–PINK1 axis coordinates redox balance and metabolic remodeling during somatic cell reprogramming. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06468-8

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06468-8

Keywords: PARK7, DJ-1, PINK1, iPSCs, reprogramming, pluripotency, reactive oxygen species, HIF-1α, NRF2, metabolic remodeling, redox biology, mitochondria