Journal of Bioenergetics and Biomembranes最新文献

The cardioprotective effects of sodium-glucose cotransporter-2 inhibitors (SGLT2i) have attracted significant attention. The calcium ion signaling pathway influences various aspects of cellular function, store-operated calcium channels (SOCCs) serve as key calcium ion channels that induce cell apoptosis and exacerbate cardiac remodeling. This study aims to investigate the effects of SGLT2i on SOCCs and its potential cardioprotective mechanisms. Sprague-Dawley (SD) rats were sequentially treated with angiotensin II (Ang II) and dapagliflozin (Dapa), randomly divided into four groups: Sham, Dapa, Ang II, and Ang II + Dapa. Blood pressure, cardiac structure and function were measured. Cardiac fibrosis evaluated using Masson's trichrome staining. The apoptosis rate of H9C2 cells was determined by flow cytometry. Protein expression levels and functional activity of SOCCs were analyzed using Western blotting, calcium imaging, and fluorescence co-localization staining. In Ang II-induced hypertension rats, no significant blood pressure lowering effect of Dapa was observed within 28 days. Notably, the absence of blood pressure reduction did not affect the timely improvement of Ang II-induced cardiac remodeling by Dapa. Ang II enhanced store-operated calcium entry (SOCE), subsequently promoting cardiomyocyte apoptosis. Dapa administration effectively suppressed this pathological process by inhibiting the overexpression and overactivation of SOCC. SGLT2i improved early cardiac remodeling induced by Ang II without relying on antihypertensive effects, mainly by inhibiting excessive activation of SOCE, which effectively attenuated Ang II-triggered cardiomyocyte apoptosis. This provides a novel therapeutic paradigm targeting impaired myocardial calcium handling in hypertensive heart disease management.

Acute myeloid leukemia is a life-threaten disease. Researches have indicated that increased expression of TKT was closely related to the progression of malignant tumors. However, the mechanism of TKT in the pathogenesis of AML need to be further elucidated. Here, we showed that the expression levels of TKT was increased in AML patients and AML cells. TKT overexpression in AML cells significantly promoted the proliferation, migration and invasion of cells while TKT knockdown had opposite effects. Mechanistically. We proved that TKT was located on up-stream of RBKS and TKT promoted the growth of AML cells through RBKS. In addition, our data indicated that TKT regulates the pentose phosphate pathway via RBKS. Notably, we demonstrated that the pentose phosphate pathway is crucial for EMT program in AML cells. Taken together, this study identified the molecular mechanism by which TKT promotes AML progression, namely, TKT promotes EMT by regulating the pentose phosphate pathway through RBKS. Our results suggest that TKT maybe a novel therapeutic target for AML treatment.

Pholiota adiposa is a traditional Chinese medicine "Huangsan". Huangsan is rich in proteins, polysaccharides, which has been documented to be used in the treatment of cancer. However, the pharmacological mechanism of Huangsan in the treatment of cancer remains unclear. This research examined the anticancer mechanisms of the ethanol extract of P. adiposa (EPA) in hepatoma-bearing mice via metabolomic analysis. Male ICR mice were randomly assigned to the control (CG), model (MG), positive (25 mg/kg/day cyclophosphamide; PG), low-level EPA (LG, 100 mg/kg/day), and high-level EPA (HG, 300 mg/kg/day) groups. Various biochemical indicators were assessed via enzyme-linked immunosorbent assay, TdT-mediated dUTP nick-end labeling assay, and hematoxylin and eosin staining. Western blot was utilized to assess tumor apoptosis-related caspase-3, cleaved caspase-3, Bcl-2, Bcl-2-associated X, and vascular endothelial growth factor. Ultra-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry and chemometric approaches were applied to determine serum metabolomics. EPA substantially impacted tumor growth in vivo without causing adverse reactions, indicating liver and kidney protection. EPA significantly increased the levels of glutamine, leucine, histidine, citrulline, creatine, prostaglandin A2, and prostaglandin D2 while decreasing levels of arachidonic acid, 20-hydroxyeicosatetraenoic acid, thromboxane B2, and pyruvate. These changes reflected a reduction in protein digestion and absorption, alterations in γ-aminobutyric acid metabolism, and shifts in amino acid metabolism, particularly affecting arachidonic acid, arginine, and proline. EPA exerted significant anticancer effects in mice mainly by reducing the compensatory energy supply from branched-chain amino acids, regulating amino acid metabolism, inhibiting negative nitrogen balance, enhancing immune responses, inhibiting inflammatory mediators, and promoting tumor cell apoptosis in the tumor microenvironment.

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease characterized by aortic wall degeneration and inflammation. The molecular mechanisms underlying AAA development remain unclear. Wilms tumor 1-associated protein (WTAP) has been implicated in various biological processes, but its role in AAA pathogenesis, particularly in cardiomyocyte regulation, has not been fully explored. Quantitative real-time PCR (qRT-PCR) was performed to detect the mRNA levels of WTAP and proprotein convertase subtilisin/kexin type 9 (PCSK9). Western blotting assay was used to analyze protein expression. Cell viability, proliferation, senescence, apoptosis, ferroptosis, and inflammation were assessed using cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay, SA-β-gal staining, flow cytometry, fluorometric assay, colorimetric method, and enzyme-linked immunosorbent assay. The association among PCSK9, WTAP, and IGF2BP2 was analyzed using RNA immunoprecipitation assay and dual-luciferase reporter assay. WTAP expression was upregulated in AAA and angiotensin II (Ang II)-induced human aortic smooth muscle cells (HASMCs). Ang II treatment inhibited HASMC proliferation and induced senescence, apoptosis, ferroptosis, and NLRP3 inflammasome-mediated inflammation. However, these effects were mitigated by WTAP knockdown. In addition, PCSK9 expression was increased in AAA, and WTAP stabilized PCSK9 mRNA expression in an IGF2BP2-dependent manner. Moreover, WTAP overexpression promoted senescence, apoptosis, ferroptosis, and inflammation by regulating PCSK9 in Ang II-induced HASMCs. WTAP silencing protected HASMCs from Ang II-induced senescence, apoptosis, ferroptosis, and inflammation by regulating PCSK9, suggesting a potential therapeutic target for AAA treatment.

Retinoblastoma (RB) is a malignant neoplasm originating from photoreceptor precursor cells that is common in children under 3 years of age. NOP2/Sun RNA methyltransferase family member 2 (NSUN2) is a major methyltransferase that catalyzes mammalian mRNA 5-methylcytosine (m5C) modification and has been implicated in a variety of diseases, but its mechanism in RB is still incomplete. NSUN2 was up-regulated in RB and was associated with the poor survival of patients. Silencing NSUN2 blocked the malignant behaviors of RB cells. In Y79 cells, the differentially expressed genes (DEGs) after knocking down NSUN2 were mainly concentrated in the glycolytic pathway from the GSE214685 dataset, and NSUN2 down-regulation restrained the glycolysis of RB cells. What's more, the m5C modification and mRNA stability of hexokinase domain component 1 (HKDC1) were mediated by NSUN2 and Y-box binding protein 1 (YBX1). Mechanically, NSUN2 promoted RB malignant behaviors and glycolysis in vitro via HKDC1 and accelerated tumor growth in vivo. Our study put forward a new mechanism to regulate RB progression, namely, NSUN2 and YBX1 synergistically promote malignant progression and glycolysis of RB by mediating HKDC1 m5C modification.

The precise pathogenic mechanisms underlying sepsis-induced acute respiratory distress syndrome (ARDS) remain incompletely characterized. Emerging evidence implicates ferroptosis of alveolar epithelial cells in ARDS pathogenesis, though the regulatory networks governing this association require further elucidation. Stimulator of interferon genes (STING), conventionally recognized as a pivotal mediator of innate immunity through DNA-sensing pathways, has recently been linked to ferroptosis. This investigation elucidates the pulmonary protective mechanisms of DMF in sepsis-induced ALI models. Experimental data revealed elevated ferroptotic activity, inflammatory markers, and oxidative stress in lungs following cecal ligation and puncture (CLP) procedures. DMF administration significantly attenuated pulmonary ferroptosis while concurrently mitigating inflammation and oxidative damage, ultimately ameliorating histological lung injury. Complementary in vitro studies demonstrated DMF's capacity to suppress lipopolysaccharide (LPS)-induced ferroptosis in MLE-12 cells. Mechanistic analyses identified dual protective pathways. DMF not only inhibited LPS-triggered STING activation and subsequent proinflammatory cytokine production but also prevented STING-mediated autophagic degradation of glutathione peroxidase 4 (GPX4). This dual action effectively reduced reactive oxygen species (ROS) accumulation and ferroptotic cell death. These findings position DMF as a promising therapeutic candidate with dual pharmacological actions - functioning as both a STING pathway inhibitor and ferroptosis suppressor.

Metabolic reprogramming characterized by aerobic glycolysis is observed in various cancers, including breast cancer (BC), exerting essential influence on maintaining cancer stemness. The abnormal expression of SPC24 is linked to the occurrence and development of various cancers, but its role in BC remains unelucidated. Bioinformatics analysis was undertaken to determine the levels of SPC24 and E2F7 in BC, and the enriched signaling pathways of SPC24 with differential expression, which were validated through cell experiments. The transcriptional regulatory relationship between E2F7 and SPC24 was also assessed through bioinformatics analysis, with validation completed by dual luciferase assay and chromatin immunoprecipitation (ChIP). To evaluate BC stemness, we employed the western blot (WB) to detect the levels of CD44, CD133, Oct-4, and ALDH1A1, and conducted the cell sphere formation. Flow cytometry was used to detect the proportion of stem cells. To assess the level of glycolysis in BC cells, we detected the expression of key proteins LDHA, HK2, and GLUT1 through WB, and measured the extracellular acidification rate and oxygen consumption rate with kits. Cell experiments combining bioinformatics analysis demonstrated that both E2F7 and SPC24 were greatly upregulated in BC, with SPC24 primarily enriched in the glycolysis metabolic pathway. Further experiments manifested that SPC24 reinforced cell stemness through aerobic glycolysis reprogramming, and SPC24 was modulated by transcription factor E2F7. E2F7 transcriptionally activates the upregulation of SPC24 in BC, which boosts stemness through aerobic glycolysis reprogramming.

Uncoupling proteins (UCPs) are mitochondrial membrane proteins involved in metabolite transportation and proton translocation to the mitochondrial matrix. Seven UCP homologs have been reported in bilaterians; however, UCPs of early-branching animals (i.e., members of Cnidaria, Ctenophora, Placozoa, and Porifera) remain understudied. The presence of UCPs in the cnidarian jellyfish Stomolophus sp.2. was investigated, and its UCP homologs were compared with data from 49 other early-branching species to provide insights into their evolution. Three UCPs were identified in Stomolophus sp.2: UCP4, UCP5, and a novel cnidarian-specific homolog (cnUCP). In addition to cnidarians, placozoans and sponges share UCP4 and UCP5 homologs, while ctenophores lack these but possess three distinct UCPs, two of them related to UCP5. Results suggest that since UCP4 and UCP5 originated at least at the Animalia-Choanoflagellata node and considering the evolutionary gains of UCPs in Cnidaria and Ctenophora, the relevance of these proteins in mitochondrial functions deserves attention. Moreover, to infer the role of UCPs in Stomolophus sp.2 mitochondria, their structural characteristics were identified, and the temperature effect on their gene expression was evaluated. Whereas UCP4 and UCP5 genes showed higher expression at 23 °C, cnUCP was highly expressed at 33 °C, suggesting a potential role in the jellyfish thermal stress response. Besides their role in mitochondrial uncoupling and energy balance, the bilaterian UCPs may mitigate reactive oxygen species production during thermal stress. However, their role in early-branching lineages remains unclear. This study provides key data for future functional research on UCPs in early-branching animals under climate change.

Brain microvascular endothelial cell injury is an important pathological basis for blood-brain barrier damage in ischemic stroke. Mollugin is a bioactive phytochemical constituent from Rubia cordifolia L., which has a protective potential in some diseases. However, the biological mechanism of mollugin in cerebrovascular damage in ischemic stroke is unknown. Human brain microvascular endothelial cells (hBMECs) were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to mimic the cerebrovascular damage in ischemic stroke. Cell viability was measured via MTT. Cell death was evaluated via flow cytometry, LDH release assay, and western blotting. Cell permeability was examined via FITC-dextran permeability assay and western blotting. Mollugin mitigated OGD/R-induced viability reduction of hBMECs. Moreover, mollugin attenuated OGD/R-induced increase in apoptotic rate, LDH release, and cleaved caspase-3 level and decrease in Bcl-2 level. Furthermore, mollugin attenuated OGD/R-induced increase in permeability and decrease in Zonula occludens-1 (ZO-1) and Claudin-5 levels. In addition, mollugin mitigated OGD/R-induced BDNF/TrkB and Akt pathways. BDNF or Akt knockdown reversed the protective effects of mollugin on cell death and permeability of hBMECs. The findings suggest that mollugin attenuates cell death and permeability of hBMECs induced by OGD/R through activating BDNF/TrkB-modulated Akt pathway.

Glutamine is well recognized as critical to the growth of most cell types. Within mitochondria glutamine is converted to glutamate by glutaminase. Oxaloacetate and glutamate then react to form alpha-ketoglutarate (α-KG) and aspartate catalyzed by glutamic-oxaloacetic transaminase (GOT2) or directly converted to α-KG by glutamate dehydrogenase (GDH). We investigated the role of GOT2 in mediating glutamate metabolism and cell growth in undifferentiated C2C12 cells. CRISPR mediated GOT2 knockout (KO) impaired cell growth, partially overcome by higher concentrations of glutamine. Mitochondrial respiration did not differ between KO and wildtype (WT) cells. Metabolite profiling showed that GOT2KO decreased aspartate by about 50% in KO versus WT cells. In contrast, α-KG increased. Metabolites reflecting the pentose phosphate pathway were significantly increased in KO cells. Metabolic pathway analyses revealed alteration of the TCA cycle, the pentose phosphate pathway, and amino acid metabolism. Glutamine ¹³C-tracing revealed decreased generation of aspartate, increased ribulose phosphate and evidence for reductive carboxylation of α-KG to isocitrate in KO cells. GDH expression was detected in C2C12 cells but did not differ between WT and GOT2KO mitochondria. GDH is not or barely expressed in adult muscle, however, we observed clear expression in pre-weanling mice. Cytosolic glutamic-oxaloacetic transaminase, GOT1, expression did not differ between GOT2KO and WT cells. In summary, GOT2 is necessary for glutamate flux and generation of downstream metabolites needed for the growth of C2C12 myoblasts. Although respiration did not differ, lack of aspartate and other compounds needed for cell proliferation may have been major factors impairing growth.