Pairwise multiplex CRISPR/Cas9 screen of mitophagy receptors in acute myeloid leukemia
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ABSTRACT:
PROVIDER: PRJNA868774 | ENA |
REPOSITORIES: ENA
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Project description:The selective autophagic degradation of mitochondria via mitophagy is essential for preserving mitochondrial homeostasis and thereby disease maintenance and progression in acute myeloid leukemia. The process of mitophagy is orchestrated by a variety of mitophagy receptors whose interplay in AML is not well understood. Here, we established a dual multiplexed CRISPR screen targeting mitophagy receptors to elucidate redundancies and individual contributions of mitophagy receptors and gain a deeper understanding of the functional interactome governing mitophagy in AML.
2023-07-11 | GSE211073 | GEO
Project description:Emerging 3D genome mapping efforts suggest complex chromosomal folding structures. However, the true multiplex nature of chromatin interactions has yet to be fully explored. Here, we describe a chromatin interaction analysis by droplet-based sequencing (ChIA-Drop). In ChIA-Drop, individual chromatin complexes are partitioned into droplets that contain a gel bead of DNA-barcoded primers, such that tethered chromatin DNA fragments are uniquely indexed and amplified for sequencing and mapping to demarcate multiplex chromatin contacts. Thus, ChIA-Drop can identify complex chromatin interactions with unprecedented single-molecule precision, which is not possible using methods that analyze pairwise contacts via proximity ligation. We demonstrate that multiplex chromatin interactions predominantly contribute to topologically associated domains with high heterogeneity, and that multivalent promoter-centered interactions provide a topological model for gene transcription.
2019-02-11 | GSE109355 | GEO
Project description:Therapeutic genome editing with Staphylococcus aureus Cas9 (SaCas9) requires a rigorous understanding of its potential off-target activity in the human genome. Here we report a high-throughput screening approach to measure SaCas9 genome editing variation in human cells across a large repertoire of 88,692 single guide RNAs (sgRNAs) paired with matched or mismatched target sites in a synthetic cassette. We incorporate randomized barcodes that enable whitelisting of correctly synthesized molecules for further downstream analysis, in order to circumvent the limitation of oligonucleotide synthesis errors. We find SaCas9 sgRNAs with 21-mer or 22-mer spacer sequences are generally more active, although high efficiency 20-mer spacers are markedly less tolerant of mismatches. Using this dataset, we developed an SaCas9 specificity model that performs robustly in ranking off-target sites. The barcoded pairwise library screen enabled high-fidelity recovery of guide-target relationships, providing a scalable framework for the investigation of CRISPR enzyme properties and general nucleic acid interactions.
| S-EPMC6063963 | biostudies-literature
Project description:Bladder cancer is one of the most common malignancy in the urinary tract with high recurrence and drug resistance in clinics. Alternative treatments from existing drugs might be a promising strategy. Nitazoxanide (NTZ), an FDA-approved antiprotozoal drug, has got increasingly noticed because of its favorable safety profile and antitumor potential, yet the effects in bladder cancer and underlying mechanisms remain poorly understood. Herein, we find that NTZ induces mitochondrial damage and mitophagy initiation through PINK1-generated phospho-ubiquitin(pS65-Ub) and autophagy receptor-mediated pathway even in the absence of Atg5/Beclin1. Meanwhile, NTZ inhibits lysosomal degradation activity, leading to mitophagy flux impairment at late stage. Mitochondrial reactive oxygen species (ROS) production is critical in this process, as eliminating ROS with N-acetylcysteine (NAC) efficiently inhibits PINK1 signaling-mediated mitophagy initiation and alleviates lysosomal dysfunction. Co-treatment with NTZ and autophagy inhibitor Chloroquine (CQ) to aggravate mitophagy flux impairment promotes NTZ-induced apoptosis, while alleviation of mitophagy flux impairment with ROS scavenger reduced cell death. Moreover, we also discover a similar signaling response in the 3D bladder tumor spheroid after NTZ exposure. In vivo study reveals a significant inhibition of orthotopic bladder tumors with no obvious systemic toxicity. Together, our results uncover the anti-tumor activities of NTZ with the involvement of ROS-mediated mitophagy modulation at different stages and demonstrate it as a potential drug candidate for fighting against bladder tumors.
2021-03-31 | GSE171129 | GEO
Project description:Mitochondria are vital for cellular energy supply and intracellular signaling after stress. Here, we aimed to investigate how mitochondria respond to acute DNA damage with respect to mitophagy, which is an important mitochondrial quality control process. Our results show that mitophagy increases after DNA damage in primary fibroblasts, murine neurons, and C. elegans neurons. Our results indicate that modulation of mitophagy after DNA damage is independent of the type of DNA damage stimuli used and that the protein Spata18 is an important player in this process. Knockdown of Spata18 suppresses mitophagy, disturbs mitochondrial Ca2+ homeostasis, affects ATP production, and attenuates DNA repair. Importantly, mitophagy after DNA damage is a vital cellular response to maintain mitochondrial functions and DNA repair.
2020-05-27 | GSE150273 | GEO
Project description:BH3 mimetics are used as an efficient strategy to promote mitochondrial-dependent cell death in blood malignancies, including acute myeloid leukemia (AML). Venetoclax, a potent BCL2 antagonist, is used clinically in combination with hypomethylating agents for the treatment of AML, while various compounds targeting MCL1 are in clinical trials. Yet, drug resistance eventually ensues, highlighting the urgency to understand the underlying mechanisms. Our genome-wide CRISPR/Cas9 screens revealed that loss of mitophagy regulators sensitizes AML to BH3 mimetics. One such regulator is Mitofusin-2 (MFN2), a GTPase that controls mitochondrial dynamics and the degradation of damaged mitochondria through mitophagy. Resistance to BH3 mimetics is accompanied by alterations in mitochondrial morphology, enhanced mitochondria-endoplasmic reticulum interactions, and augmented mitophagy flux. MFN2 inactivation, using a novel small molecule inhibitor, and pharmacologic inhibition of mitophagy synergizes with BH3 mimetics. Overall, targeting of mitophagy along with BCL2-family members is a promising strategy to overcome drug resistance in AML.
2023-07-10 | GSE182401 | GEO
Project description:Mitophagy is essential to maintain mitochondrial function and prevent diseases. It activates upon mitochondria depolarization, which causes PINK1 stabilization on the mitochondrial outer membrane. Strikingly, a number of conditions, including mitochondrial protein misfolding, can induce mitophagy without a loss in membrane potential. The underlying molecular details remain unclear. Here, we report that a loss of mitochondrial protein import, mediated by the pre-sequence translocase-associated motor complex PAM, is sufficient to induce mitophagy in polarized mitochondria. A genome-wide CRISPR/Cas9 screen for mitophagy inducers identifies components of the PAM complex. Protein import defects are able to induce mitophagy without a need for depolarization. Upon mitochondrial protein misfolding, PAM dissociates from the import machinery resulting in decreased protein import and mitophagy induction. Our findings extend the current mitophagy model to explain mitophagy induction upon conditions that do not affect membrane polarization, such as mitochondrial protein misfolding.
2022-08-04 | GSE207212 | GEO
Project description:Upon mitochondrial dysfunction, mitophagy has been described to be activated by a breakdown of membrane potential leading to PINK1 accumulation on the outer membrane and engulfment of mitochondria for degradation. However, recent findings have indicated that mitophagy may also be triggered in the absence of membrane potential alterations. Here, we report mechanistic details on how inhibition of protein import induces mitophagy independent of mitochondrial membrane depolarization. Carrying out a genome-wide CRISPR/Cas9 screen for regulators of mitophagy, we found that the pre-sequence translocase-associated motor complex PAM controls mitophagy induction. Loss of PAM caused defects in protein import and was sufficient to induce mitophagy without depolarization. Quantitative interaction and aggregation proteomics revealed that PAM was highly sensitive to proteostasis perturbation; upon misfolding conditions, PAM dissociated from the import machinery, sequestered into the insoluble fraction and caused mitophagy despite an intact membrane potential. Our findings extend the current mitophagy model and provide mechanistic insight into how proteostasis perturbation leads to mitophagy induction. They reveal the PAM complex as key folding sensor integrating proteostasis, import and mitophagy.
2022-09-03 | PXD022560 | Pride
Project description:The random-pattern skin flap is a crucial technique in reconstructive surgery and flap necrosis caused by ischemia/reperfusion injury is a major postoperative complication. Herein, we investigated the mechanism of mitophagy induced by Melatonin (ML) and its effect on the survival of skin flaps. Our results demonstrated that ML could activate mitophagy, ameliorate oxidative stress and alleviate apoptosis in TBHP-stimulated human umbilical vein endothelial cells in vitro. Inhibiting ML-induced mitophagy considerably abolished its protective effects. Moreover, knockdown of Parkin by siRNA inhibited ML-induced mitophagy, and subsequently exacerbated oxidative stress and apoptosis. Further study demonstrated that inhibition of AMPK reversed these protective effects of ML and downregulated the expression of TFEB. In the vivo study, ML effectively promoted flap survival by activating mitophagy and subsequently ameliorating oxidative stress and mitigating apoptosis. These results established that ML is a potent agent capable for increasing random-pattern skin flap survival by activating Parkin-dependent mitophagy through the AMPK-TFEB signaling pathway.
2022-06-29 | GSE203609 | GEO