Involvement of DJ-1 in the pathogenesis of intervertebral disc degeneration via hexokinase 2-mediated mitophagy.

Intervertebral disc degeneration (IDD) is an important pathological basis for degenerative spinal diseases and is involved in mitophagy dysfunction. However, the molecular mechanisms underlying mitophagy regulation in IDD remain unclear. This study aimed to clarify the role of DJ-1 in regulating mitophagy during IDD pathogenesis. Here, we showed that the mitochondrial localization of DJ-1 in nucleus pulposus cells (NPCs) first increased and then decreased in response to oxidative stress. Subsequently, loss- and gain-of-function experiments revealed that overexpression of DJ-1 in NPCs inhibited oxidative stress-induced mitochondrial dysfunction and mitochondria-dependent apoptosis, whereas knockdown of DJ-1 had the opposite effect. Mechanistically, mitochondrial translocation of DJ-1 promoted the recruitment of hexokinase 2 (HK2) to damaged mitochondria by activating Akt and subsequently Parkin-dependent mitophagy to inhibit oxidative stress-induced apoptosis in NPCs. However, silencing Parkin, reducing mitochondrial recruitment of HK2, or inhibiting Akt activation suppressed DJ-1-mediated mitophagy. Furthermore, overexpression of DJ-1 ameliorated IDD in rats through HK2-mediated mitophagy. Taken together, these findings indicate that DJ-1 promotes HK2-mediated mitophagy under oxidative stress conditions to inhibit mitochondria-dependent apoptosis in NPCs and could be a therapeutic target for IDD.

Microglial hexokinase 2 deficiency increases ATP generation through lipid metabolism leading to ß-amyloid clearance.

Microglial cells consume adenosine triphosphate (ATP) during phagocytosis to clear neurotoxic ß-amyloid in Alzheimer's disease (AD). However, the contribution of energy metabolism to microglial function in AD remains unclear. Here, we demonstrate that hexokinase 2 (HK2) is elevated in microglia from an AD mouse model (5xFAD) and AD patients. Genetic deletion or pharmacological inhibition of HK2 significantly promotes microglial phagocytosis, lowers the amyloid plaque burden and attenuates cognitive impairment in male AD mice. Notably, the ATP level is dramatically increased in HK2-deficient or inactive microglia, which can be attributed to a marked upregulation in lipoprotein lipase (LPL) expression and subsequent increase in lipid metabolism. We further show that two downstream metabolites of HK2, glucose-6-phosphate and fructose-6-phosphate, can reverse HK2-deficiency-induced upregulation of LPL, thus supporting ATP production and microglial phagocytosis. Our findings uncover a crucial role for HK2 in phagocytosis through regulation of microglial energy metabolism, suggesting a potential therapeutic strategy for AD by targeting HK2.

Hexokinase II expression as a prognostic marker in diffuse large B-cell lymphoma: pre- and post-rituximab era.

We aimed to assess HKII expression and its prognostic significance in diffuse large B-cell lymphoma (DLBCL) patients. The HKII protein level was determined by immunohistochemistry in 159 newly diagnosed DLBCL patients, and its relationship with overall response rate, progression-free survival (PFS), and overall survival (OS) was analyzed. HKII was expressed in 95 DLBCL patients (59.7%). HKII-positive patients had poorer outcomes than negative patients for 5-y PFS (68% vs. 84%, p = 0.029) and 5-y OS (78% vs. 94%, p = 0.05). When only patients without no bulky disease, B symptoms, or extranodal involvement who had low IPI scores were considered, those with positive HKII had worse 5y-PFS and 5y-OS (p < 0.05). Multivariate analysis indicated that HKII status was an independent prognostic factor of OS. In subgroup analysis, HKII expression was associated with inferior OS in the CHOP group (p = 0.017). In CHOP group patients without bulky disease or extranodal involvement who had low LDH and low IPI scores (p < 0.05), positive HKII was associated with worse PFS and OS. No differences in PFS and OS, or any independent prognostic factors, were found in the RCHOP group. In DLBCL, HKII is valuable as a prognostic biomarker and may be useful as a tool for assessing disease risk.

AKT1/HK2 Axis-mediated Glucose Metabolism: A Novel Therapeutic Target of Sulforaphane in Bladder Cancer.

SCOPE: Metabolic disorder is a pivotal hallmark of cancer cells. Sulforaphane (SFN) is reported to improve lipid metabolism. However, the effect of SFN on glucose metabolism in bladder cancer remains unclear. Hence, the effect and underling mechanism is investigated. METHODS AND RESULTS: Biological samples from bladder cancer patients are collected, and also investigated using N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder cancer mice and bladder cancer cell lines. A novel glucose transport aberrant-independent aerobic glycolysis is found in bladder cancer patients, and the lower malignancy tissues have the more obvious abnormality. SFN strongly downregulates ATP production by inhibiting glycolysis and mitochondrial oxidative phosphorylation (OXPHOS). Both in vitro cell culture and in bladder tumor mice, SFN weaken the glycolytic flux by suppressing multiple metabolic enzymes, including hexokinase 2 (HK2) and pyruvate dehydrogenase (PDH). Moreover, SFN decreases the level of AKT1 and p-AKT ser473 , especially in low-invasive UMUC3 cells. The downregulation of ATP and HK2 by SFN is both reversed by AKT1 overexpression. CONCLUSIONS: SFN downregulates the unique glucose transport aberrant-independent aerobic glycolysis existed in bladder cancer via blocking the AKT1/HK2 axis and PDH expression.

Wound healing in children as assessed by the CELLSTIC method.

Assessment of the quality and speed of wound healing in man has been rather difficult until the present time. By the use of CEELSTIC, a tissue-sensitive test drain composed of a standardized piece of viscose cellulose sponge inside a thin Silastic tube, cells existing between wound edges can be analyzed by histologic, cytologic, and enzyme histochemical means. The 166 pediatric surgical patients studied showed that wound healing is an age-dependent process reflected by the increased time needed for cellular transformation and maximal activation of hexokinase and isocitrate dehydrogenase with increasing age.