Enhancement of ubiquitination-dependent mitophagy by unconventionally-acting PROTACs
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ABSTRACT:
PROVIDER: PRJNA1074729 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR27919014_1.fastq.gz | Fastqsanger.gz | |||
| SRR27919014_2.fastq.gz | Fastqsanger.gz | |||
| SRR27919015_1.fastq.gz | Fastqsanger.gz | |||
| SRR27919015_2.fastq.gz | Fastqsanger.gz | |||
| SRR27919016_1.fastq.gz | Fastqsanger.gz |
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Project description:Enhancing mitophagy, a naturally-occurring cellular process for elimination of damaged mitochondria, holds great promise for the intervention of many human diseases. Proteolysis-targeting chimeras (PROTACs) are heterobifunctional molecules that induce ubiquitination and subsequent proteasome-mediated degradation of a target protein through simultaneously binding to the target protein and an E3 ubiquitin ligase. However, the narrow cavity of the proteasome prevents the degradation of mitochondria. Here we show that the E3 ubiquitin ligase MAP3K1, when recruited to the outer mitochondria membrane (OMM) protein TSPO by our PROTAC-designed molecules (termed “mitophagy-enhancing chimeras”, or MECs), induced extensive K63 ubiquitination of TSPO and other OMM proteins, reminiscent of the PINK1-activated Parkin, without triggering proteasome-mediated degradation of TSPO. Aided by NBR1 and Nur77, this increased K63 ubiquitination of OMM proteins triggered mitophagy exclusively for damaged mitochondria, leading to improved mitochondria function and diminished cellular ROS. With the capability to enhance mitophagy at low nanomolar concentrations, MECs effectively inhibited NLRP3 inflammasome activation, abrogated acetaminophen-induced acute liver injury and mitigated high-fat diet-induced obesity in mice. Our work provided a proof-of-concept for developing unconventionally-acting PROTACs to achieve degradation of damaged mitochondria and possibly other organelles.
2024-02-08 | GSE255354 | GEO
Project description:The Ubiquitin Ligase RBX2/SAG Regulates Mitochondrial Ubiquitination and Mitophagy
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Project description:Clearance of damaged mitochondria via mitophagy is crucial for cellular homeostasis. While the role of ubiquitin (Ub) ligase PARKIN in mitophagy has been extensively studied, increasing evidence suggests the existence of PARKIN-independent mitophagy in highly metabolically active organs such as the heart. Here, we identify a crucial role for Cullin-RING Ub ligase 5 (CRL5) in basal mitochondrial turnover in cardiomyocytes. CRL5 is a multi-subunit Ub ligase comprised by the catalytic RING box protein RBX2 (also known as SAG), scaffold protein Cullin 5 (CUL5), and a substrate-recognizing receptor. Analysis of the mitochondrial outer membrane-interacting proteome uncovered a robust association of CRLs with mitochondria. Subcellular fractionation, immunostaining, and immunogold electron microscopy established that RBX2 and Cul5, two core components of CRL5, localizes to mitochondria. Depletion of RBX2 inhibited mitochondrial ubiquitination and turnover, impaired mitochondrial membrane potential and respiration, and increased cell death in cardiomyocytes. In vivo, deletion of the Rbx2 gene in adult mouse hearts suppressed mitophagic activity, provoked accumulation of damaged mitochondria in the myocardium, and disrupted myocardial metabolism, leading to rapid development of dilated cardiomyopathy and heart failure. Similarly, ablation of RBX2 in the developing heart resulted in dilated cardiomyopathy and heart failure. Notably, the action of RBX2 in mitochondria is not dependent on PARKIN, and PARKIN gene deletion had no impact on the onset and progression of cardiomyopathy in RBX2-deficient hearts. Furthermore, RBX2 controls the stability of PINK1 in mitochondria. Proteomics and biochemical analyses further revealed a global impact of RBX2 deficiency on the mitochondrial proteome and identified several mitochondrial proteins as its putative substrates. These findings identify RBX2-CRL5 as a mitochondrial Ub ligase that controls mitophagy under physiological conditions in a PARKIN-independent, PINK1-dependent manner, thereby regulating cardiac homeostasis.
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Project description:PROteolysis TArgeting Chimeras (PROTACs) are bifunctional small molecules that can simultaneously recruit target protein and E3 ligase to form a ternary complex (target protein / PROTAC / E3 ligase), leading to target protein ubiquitination and degradation via the Ubiquitin-Proteasome System (UPS). PROTACs have gained increasing attention in recent years due to certain advantages over traditional therapeutic modalities enabling targeting of previously "undruggable" proteins. To better understand the mechanism of PROTAC-induced Target Protein Degradation (TPD), several computational approaches have recently been developed to study and predict ternary complex formation. However, mounting evidence suggests that ubiquitination can also be a rate-limiting step in PROTAC induced TPD. Here, we propose a structure-based computational approach to predict target protein ubiquitination induced by CRBN-based PROTACs,
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2025-07-17 | GSE273724 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA) is a CAG/polyglutamine (polyQ) repeat expansion disorder in which the mutant androgen receptor (AR) protein triggers progressive degeneration of the neuromuscular system in men. As the misfolded polyQ AR is the proximal mediator of toxicity, therapeutic efforts have focused on targeting the mutant protein, but these prior efforts have met with limited success in SBMA patients. Here, we examine the efficacy of proteolysis targeting chimeras (PROTACs), small molecule AR degraders that rapidly and potently promote AR ubiquitination and degradation by the proteasome. We identify ARD-1676 as a PROTAC that clears polyQ AR in an over-expression system, in patient iPSC-derived induced motor neurons and skeletal muscle cells, and in a gene targeted mouse model of disease. Furthermore, we demonstrate that 24-hour treatment with ARD-1676 rescues transcriptional dysregulation in SBMA induced skeletal muscle cells. These data provide evidence of therapeutic efficacy and in vivo target engagement, establishing PROTACs as potential therapeutic agents for the treatment of SBMA.
2025-12-09 | GSE297069 | GEO
Project description:HEP14 treatment improves ovarian function in aged mice through mitophagy enhancement and oxidative stress reducton
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Project description:The PINK1/Parkin pathway is responsible for targeting damaged mitochondria for degradation via mitophagy. Because genetic evidence links impaired mitophagy to Parkinson’s disease, pharmacologic enhancement of mitophagy represents a promising disease-modifying strategy. Here, we characterize two pharmacological mitophagy activators: a new Parkin activator, FB231, described here and the reported PINK1 activator MTK458. We demonstrate that both compounds activate their targets and lower the threshold for PINK1/Parkin-mediated mitophagy induced by mitochondrial stressors. Using global proteomics, however, we also find that FB231 and MTK458 exert mild mitochondrial stress that leads to cleavage of OPA1 and activation of the integrated stress response, in a PINK1/Parkin-independent manner. Both compounds cause mitochondrial stress and thereby sensitizes cells to mitophagy induction by classical mitochondria toxins. We provide a model that rationalizes this hitherto unknown mechanism for mitophagy activators, whereby normally “silent” mitochondrial toxins can act as potent PINK1/Parkin potentiators in the context of mitochondrial stress.
2025-06-03 | PXD058150 | Pride
Project description:Breast cancer (BCa) remains the second leading cause of cancer-related mortalities in women, and acquired resistance to hormone therapies, such as tamoxifen, an estrogen receptor inhibitor, is a major hurdle in the treatment of luminal BCa. Another subtype, triple negative BCa (TNBC), is associated with aggressive disease and poor prognosis. The enhancer of zeste homolog 2 (EZH2), the methyltransferase component of the polycomb repressive complex 2 (PRC2), is overexpressed in BCa and has been implicated in tamoxifen resistance. In addition to its PRC2-dependent canonical transcription repressive role through catalyzing histone 3 lysine 27 trimethylation (H3K27me3), evidence suggests that EZH2 can function noncanonically, in a methyltransferase-independent manner, as a transcription activator through interacting with hormone receptors and oncogenic transcription factors. Unlike methyltransferase inhibitors, proteolysis targeting chimeras (PROTAC), which target EZH2 and interacting proteins for degradation, can suppress both activating and repressive functions of EZH2. Previous studies have suggested that PROTACs can be leveraged to inhibit TNBC cell growth. In this study, we expand our scope to test whether EZH2 targeted PROTACs can effectively inhibit luminal BCa cell growth. We find that EZH2-targeted PROTACs, MS177 and MS8815, effectively inhibited the growth luminal BCa cells, including those with acquired tamoxifen resistance, to a much greater degree when compared to methyltransferase inhibitors. Similarly, PROTACs uniquely reduced the expression of genes involved in cell cycle progression, including forkhead box M1 (FOXM1) target genes, in BCa cell lines. Likewise, promoter regions with EZH2 binding in the absence of H3K27me3 were enriched with FOXM1 target genes in both luminal BCa and TNBC cell lines, suggesting a regulatory mechanism independent of hormone receptor status. EZH2 PROTAC treatment reduced FOXM1 protein expression and increased its degradation. In clinical samples, EZH2 mRNA expression tightly correlated with FOXM1 and FOXM1 target genes. Together, this study suggests that EZH2 targeted PROTACs represent a promising avenue of research for the future treatment of BCa, including in the setting of tamoxifen resistance.
2025-05-01 | GSE270769 | GEO
Project description:Breast cancer (BCa) remains the second leading cause of cancer-related mortalities in women, and acquired resistance to hormone therapies, such as tamoxifen, an estrogen receptor inhibitor, is a major hurdle in the treatment of luminal BCa. Another subtype, triple negative BCa (TNBC), is associated with aggressive disease and poor prognosis. The enhancer of zeste homolog 2 (EZH2), the methyltransferase component of the polycomb repressive complex 2 (PRC2), is overexpressed in BCa and has been implicated in tamoxifen resistance. In addition to its PRC2-dependent canonical transcription repressive role through catalyzing histone 3 lysine 27 trimethylation (H3K27me3), evidence suggests that EZH2 can function noncanonically, in a methyltransferase-independent manner, as a transcription activator through interacting with hormone receptors and oncogenic transcription factors. Unlike methyltransferase inhibitors, proteolysis targeting chimeras (PROTAC), which target EZH2 and interacting proteins for degradation, can suppress both activating and repressive functions of EZH2. Previous studies have suggested that PROTACs can be leveraged to inhibit TNBC cell growth. In this study, we expand our scope to test whether EZH2 targeted PROTACs can effectively inhibit luminal BCa cell growth. We find that EZH2-targeted PROTACs, MS177 and MS8815, effectively inhibited the growth luminal BCa cells, including those with acquired tamoxifen resistance, to a much greater degree when compared to methyltransferase inhibitors. Similarly, PROTACs uniquely reduced the expression of genes involved in cell cycle progression, including forkhead box M1 (FOXM1) target genes, in BCa cell lines. Likewise, promoter regions with EZH2 binding in the absence of H3K27me3 were enriched with FOXM1 target genes in both luminal BCa and TNBC cell lines, suggesting a regulatory mechanism independent of hormone receptor status. EZH2 PROTAC treatment reduced FOXM1 protein expression and increased its degradation. In clinical samples, EZH2 mRNA expression tightly correlated with FOXM1 and FOXM1 target genes. Together, this study suggests that EZH2 targeted PROTACs represent a promising avenue of research for the future treatment of BCa, including in the setting of tamoxifen resistance.
2025-05-01 | GSE270163 | GEO