The mechanisms linking muscle injury and regeneration are not fully understood. Here we report an unexpected role for ZEB1 regulating inflammatory and repair responses in dystrophic and acutely ...injured muscles. ZEB1 is upregulated in the undamaged and regenerating myofibers of injured muscles. Compared to wild-type counterparts, Zeb1-deficient injured muscles exhibit enhanced damage that corresponds with a retarded p38-MAPK-dependent transition of their macrophages towards an anti-inflammatory phenotype. Zeb1-deficient injured muscles also display a delayed and poorer regeneration that is accounted by the retarded anti-inflammatory macrophage transition and their intrinsically deficient muscle satellite cells (MuSCs). Macrophages in Zeb1-deficient injured muscles show lower phosphorylation of p38 and its forced activation reverts the enhanced muscle damage and poorer regeneration. MuSCs require ZEB1 to maintain their quiescence, prevent their premature activation following injury, and drive efficient regeneration in dystrophic muscles. These data indicate that ZEB1 protects muscle from damage and is required for its regeneration.
Human embryonic stem cells (hESCs) can differentiate into any cell lineage. Here, we report that ZEB1 and ZEB2 promote and inhibit mesodermal-to-myogenic specification of hESCs, respectively. ...Knockdown and/or overexpression experiments of ZEB1, ZEB2, or PAX7 in hESCs indicate that ZEB1 is required for hESC Nodal/Activin-mediated mesodermal specification and PAX7+ human myogenic progenitor (hMuP) generation, while ZEB2 inhibits these processes. ZEB1 downregulation induces neural markers, while ZEB2 downregulation induces mesodermal/myogenic markers. Mechanistically, ZEB1 binds to and transcriptionally activates the PAX7 promoter, while ZEB2 binds to and activates the promoter of the neural OTX2 marker. Transplanting ZEB1 or ZEB2 knocked down hMuPs into the muscles of a muscular dystrophy mouse model, showing that hMuP engraftment and generation of dystrophin-positive myofibers depend on ZEB1 and are inhibited by ZEB2. The mouse model results suggest that ZEB1 expression and/or downregulating ZEB2 in hESCs may also enhance hESC regenerative capacity for human muscular dystrophy therapy.
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•ZEB1 is required for the generation of mesodermal and myogenic (PAX7+) progenitors•Downregulation of ZEB1 and ZEB2 induces neural and myogenic markers, respectively•ZEB1 and ZEB2 activate the promoters of myogenic PAX7 and neural OTX2, respectively•Engraftment of myogenic precursors in mdx mice depends on ZEB1 and is inhibited by ZEB2
Ninfali et al. report that ZEB1 is required for the mesodermal-to-myogenic specification of human embryonic stem cells (hESCs) and their engraftment into mouse dystrophic muscles, while ZEB2 inhibits both processes. The study suggests that modulating ZEB1 and ZEB2 in hESCs could be an approach to enhance hESC regenerative capacity in muscular dystrophies.
Acute inflammation can either resolve through immunosuppression or persist, leading to chronic inflammation. These transitions are driven by distinct molecular and metabolic reprogramming of immune ...cells. The anti-diabetic drug Metformin inhibits acute and chronic inflammation through mechanisms still not fully understood. Here, we report that the anti-inflammatory and reactive-oxygen-species-inhibiting effects of Metformin depend on the expression of the plasticity factor ZEB1 in macrophages. Using mice lacking Zeb1 in their myeloid cells and human patient samples, we show that ZEB1 plays a dual role, being essential in both initiating and resolving inflammation by inducing macrophages to transition into an immunosuppressed state. ZEB1 mediates these diverging effects in inflammation and immunosuppression by modulating mitochondrial content through activation of autophagy and inhibition of mitochondrial protein translation. During the transition from inflammation to immunosuppression, Metformin mimics the metabolic reprogramming of myeloid cells induced by ZEB1. Mechanistically, in immunosuppression, ZEB1 inhibits amino acid uptake, leading to downregulation of mTORC1 signalling and a decrease in mitochondrial translation in macrophages. These results identify ZEB1 as a driver of myeloid cell metabolic plasticity, suggesting that targeting its expression and function could serve as a strategy to modulate dysregulated inflammation and immunosuppression.
Accumulation of lipid-laden macrophages within the arterial neointima is a critical step in atherosclerotic plaque formation. Here, we show that reduced levels of the cellular plasticity factor ZEB1 ...in macrophages increase atherosclerotic plaque formation and the chance of cardiovascular events. Compared to control counterparts (Zeb1
/Apoe
), male mice with Zeb1 ablation in their myeloid cells (Zeb1
/Apoe
) have larger atherosclerotic plaques and higher lipid accumulation in their macrophages due to delayed lipid traffic and deficient cholesterol efflux. Zeb1
/Apoe
mice display more pronounced systemic metabolic alterations than Zeb1
/Apoe
mice, with higher serum levels of low-density lipoproteins and inflammatory cytokines and larger ectopic fat deposits. Higher lipid accumulation in Zeb1
macrophages is reverted by the exogenous expression of Zeb1 through macrophage-targeted nanoparticles. In vivo administration of these nanoparticles reduces atherosclerotic plaque formation in Zeb1
/Apoe
mice. Finally, low ZEB1 expression in human endarterectomies is associated with plaque rupture and cardiovascular events. These results set ZEB1 in macrophages as a potential target in the treatment of atherosclerosis.
Abstract
Multiple physiopathological and clinical conditions trigger skeletal muscle atrophy through the induction of a group of proteins (atrogenes) that includes components of the ...ubiquitin-proteasome and autophagy-lysosomal systems. Atrogenes are induced by FOXO transcription factors, but their regulation is still not fully understood. Here, we showed that the transcription factor ZEB1, best known for promoting tumor progression, inhibits muscle atrophy and atrogene expression by antagonizing FOXO3-mediated induction of atrogenes. Compared to wild-type counterparts, hindlimb immobilization in Zeb1-deficient mice resulted in enhanced muscle atrophy and higher expression of a number of atrogenes, including Atrogin-1/Fbxo32, MuRF1/Trim63, Ctsl, 4ebp1, Gabarapl1, Psma1 and Nrf2. Likewise, in the C2C12 myogenic cell model, ZEB1 knockdown augmented both myotube diameter reduction and atrogene upregulation in response to nutrient deprivation. Mechanistically, ZEB1 directly represses in vitro and in vivo Fbxo32 and Trim63 promoter transcription in a stage-dependent manner and in a reverse pattern with MYOD1. ZEB1 bound to the Fbxo32 promoter in undifferentiated myoblasts and atrophic myotubes, but not in non-atrophic myotubes, where it is displaced by MYOD1. ZEB1 repressed both promoters through CtBP-mediated inhibition of FOXO3 transcriptional activity. These results set ZEB1 as a new target in therapeutic approaches to clinical conditions causing muscle mass loss.
Reactive oxygen species (ROS) serve important homeostatic functions but must be constantly neutralized by an adaptive antioxidant response to prevent supraphysiological levels of ROS from causing ...oxidative damage to cellular components. Here, we report that the cellular plasticity transcription factors ZEB1 and ZEB2 modulate in opposing directions the adaptive antioxidant response to fasting in skeletal muscle. Using transgenic mice in which
or
were specifically deleted in skeletal myofibers, we show that in fasted mice, the deletion of
, but not
, increased ROS production and that the adaptive antioxidant response to fasting essentially requires ZEB1 and is inhibited by ZEB2. ZEB1 expression increased in fasted muscles and protected them from atrophy; conversely, ZEB2 expression in muscles decreased during fasting and exacerbated muscle atrophy. In fasted muscles, ZEB1 reduces mitochondrial damage and increases mitochondrial respiratory activity; meanwhile, ZEB2 did the opposite. Treatment of fasting mice with
-deficient myofibers with the antioxidant triterpenoid 12-cyano-3,12-dioxool-eana-1,9(11)-dien-28-oyl trifluoro-ethylamide (CDDO-TFEA) completely reversed their altered phenotype to that observed in fasted control mice. These results set ZEB factors as potential therapeutic targets to modulate the adaptive antioxidant response in physiopathological conditions and diseases caused by redox imbalance.
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