The Metabolic Enzyme Hexokinase 2 Localizes to the Nucleus in AML and Normal Hematopoietic Stem/Progenitor Cells to Maintain Stemness
Notice bibliographique
Résumé
Abstract Mitochondrial metabolites affect epigenetic marks, but it is largely unknown whether mitochondrial metabolic enzymes can directly localize to the nucleus to regulate stem cell function in AML. Here, we discovered that the mitochondrial enzyme, Hexokinase 2 (HK2), localizes to the nucleus in AML and normal hematopoietic stem cells to maintain stem cell function. We searched for mitochondrial enzymes moonlighting in the nucleus using 8227 AML cells, a low passage primary AML culture model arranged in a hierarchy with functionally defined stem cells in the CD34+CD38-fraction. By immunoblotting and confocal microscopy, we detected HK2 in the nucleus of 8227 cells with higher expression in the nucleus of stem cells vs bulk cells. HK2 is the first and rate-limiting enzyme in glycolysis and phosphorylates glucose. In contrast, other metabolic enzymes including phosphofructokinase, fumarase, pyruvate kinase 2, glucose phosphate isomerase, enolase1, citrate synthase, aconitase 2, and succinate dehydrogenase were not detected in the nucleus of these cells. We also detected HK2, but not these other metabolic enzymes, in the nucleus of OCI-AML2, U937, NB4 and TEX leukemia as well as 8 of 9 primary AML samples. Next, we tested whether nuclear HK2 was functionally important to maintain stem cell function in AML. We over-expressed HK2 tagged with nuclear localizing signals (PKKKRKV and PAAKRVKLD) in 8227 and NB4 leukemia cells. We confirmed selective over-expression of HK2 in the nucleus of these cells without increasing levels in the cytoplasm or mitochondria. Over-expression of nuclear HK2 increased clonogenic growth and inhibited retinoic acid-mediated cell differentiation without changing basal proliferation. Over expression of HK2 also increased engraftment of 8227 cells into mouse marrow. We evaluated the selective inhibition of nuclear HK2 by over-expressing HK2 with an outer mitochondrial localization signal while knocking down total endogenous HK2 with shRNA targeting the 3'UTR of HK2. Selective depletion of nuclear HK2 reduced clonogenic growth, increased AML differentiation after treatment with retinoic, and decreased the percentage of CD34+CD38- 8227 stem cells without changing basal proliferation. To determine whether nuclear HK2 maintains stemness through its kinase activity, we over-expressed a kinase dead double mutant of nuclear HK2(D209A D657A). Nuclear kinase dead HK2 increased clonogenic growth and inhibited differentiation after retinoic acid treatment, demonstrating that HK2 maintains stemness independent of its kinase function. To understand nuclear functions of HK2, we used proximity-dependent biotin labeling (BioID) and mass spectrometry to identify proteins that interact with nuclear HK2 and identified proteins related to chromatin organization and regulation. Therefore, we examined the impact of nuclear HK2 on chromatin accessibility using ATAC-seq. Over expression of nuclear HK2 enhanced chromatin accessibility, whereas the selective knockdown of nuclear HK2 compacted chromatin. In summary, we discovered that HK2 localizes to nucleus of AML cells and functions independent of its kinase activity to maintain the stem/progenitor state of AML. Thus, we define a new role for mitochondrial enzymes in the regulation of leukemic stemness and differentiation. Disclosures Dick: Bristol-Myers Squibb/Celgene: Research Funding. Schimmer:Takeda: Honoraria, Research Funding; Novartis: Honoraria; Jazz: Honoraria; Otsuka: Honoraria; Medivir AB: Research Funding; AbbVie Pharmaceuticals: Other: owns stock .
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».