Journal of Bioenergetics and Biomembranes最新文献

The P2X7 receptor (P2X7R) is an ion channel that promotes the passage of ions through the membrane through brief stimulation once activated by ATP, its endogenous opener. However, prolonged stimulation with ATP, which occurs in pathological processes, opens a nonselective pore in the plasma membrane, allowing the passage of large molecules and leading to cytokine release or even cell death. In this sense, the search for new inhibitors for this receptor has attracted a great deal of attention in recent years. Considering the booming of biomass upgrading reactions in recent years and the continued efforts to synthesize biologically active molecules containing the 1,2,3-triazole ring, in the present work, we aimed to investigate whether triazole-linked menadione-furan derivatives could present P2X7R inhibitory activity. The novel compounds were tested for their inhibitory activity on ATP-induced dye uptake in peritoneal macrophages. Some have shown promising results, having displayed IC₅₀ values lower than that of the P2X7R inhibitor BBG. Molecular docking studies also indicated that the active compounds bind to an allosteric site on P2X7R, presenting potential P2X7R inhibition.

Na,K-ATPase is a member of the P-type ATPase family, which transforms the energy of ATP to the transmembrane Na/K gradient that is used to create membrane potential, support the excitability of neurons and myocytes, control pH, and transport substances. The regulation of the Na,K-ATPase function by physiological regulators also comprises a central role in the adaptation of organisms to different conditions. H₂O₂ is one of the main signaling molecules in redox metabolism and plays important function in cellular physiology. H₂O₂ also regulates signaling pathways via the specific oxidation of proteins harboring redox-sensitive moieties, like metal centers or cysteine residues, which control their activity. The Na,K-ATPase is redox-sensitive with an "optimal redox potential range," where the reactive oxygen species (ROS), levels beyond this "optimal range" are responsible for enzyme inhibition. Thus reactive oxygen species manifest a hermetic effect, which is expressed by biphasic action; stimulation by low doses and inhibition by high doses. This study was aimed to reveal redox-sensitivity of brain synaptic membrane fractions Na,K-ATPase via H₂O₂ effects. Different concentrations of H₂O₂ change the kinetic parameters of the enzyme system for MgATP complex, Na⁺, and K⁺ differently. Moreover, H₂O₂ changes p-chloromercuribenzoic acids (PCMB) affinity. H₂O₂ targets thiols of the Na,K-ATPase - low and high concentrations of H₂O₂ change the oxidative state of thiolate (S-) from Cys differently, resulting in the corresponding activation or inhibition of the enzyme. Targeting thiols of the Na,K-ATPase tunes the activity of the Na,K-ATPase to the cellular demands and sustains the enzyme activity at the "optimal" level.

Pancreatic adenocarcinoma (PAAD) is the third leading cause of cancer-related deaths, with a 5-year relative survival rate of 6%. Hence, novel therapeutic targets need to be urgently explored for PAAD. Recently, oxidative phosphorylation (OXPHOS) has been identified to contribute to the development of PAAD. Nicotinamide adenine dinucleotide + hydrogen (NADH) dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4) is known to affect the mitochondrial respiration pathway. However, the function of NDUFA4 in PAAD remains unclear. In this study, NDUFA4 expression was examined in samples from patients with PAAD using real-time polymerase chain reaction and immunohistochemical staining. Furthermore, cell proliferation and cell cycle were analyzed using Cell Counting Kit-8 assay and flow cytometry. A xenograft tumor model derived from a PAAD cell line was developed to validate the in vitro findings. NDUFA4 was observed to be upregulated in the PAAD samples, and high levels were associated with a poor survival rate. NDUFA4 knockdown reduced cell proliferation by inducing G1 arrest in SW1990 cells. Mechanistically, NDUFA4 knockdown decreased the oxygen consumption rate, cellular adenosine triphosphate level, mitochondrial complex IV activity, and protein levels of COX6C and COX5B, which indicated the suppression of OXPHOS. In contrast, NDUFA4 overexpression exerted the opposite effects. Finally, NDUFA4 knockdown significantly inhibited the growth of the xenograft tumor derived from the SW1990 cell line in vivo. Therefore, NDUFA4 contributes to PAAD proliferation by enhancing OXPHOS.

Polycystic ovary syndrome (PCOS) is featured as a common endocrine disorder in reproductive-aged women, while its pathophysiology is not fully illustrated. This study examined potential actions of resveratrol in PCOS cellular model and explored the underlying interaction between resveratrol and toll-like receptor 2 (TLR2). This study performed the bioinformatics analysis on two microarray datasets (GSE34526 and GSE138518). We found that TLR2 was one of potential hub genes that may be associated with PCOS. Further examination showed that TLR2 was highly expressed in granulosa cells from PCOS group compared with control. The in vitro studies showed that LPS intervention caused an increased expression of TLR2 and the pro-inflammatory mediators, and induced oxidative stress in the granulosa cells, which was concentration-dependently antagonized by resveratrol treatment. TLR2 silence significantly attenuated LPS-induced increase TNF-α, IL-1β, IL-6 and IL-8 expression and oxidative stress of granulosa cells. Furthermore, TLR2 overexpression promoted inflammatory response and oxidative stress in the granulosa cells, which was antagonized by resveratrol treatment. In conclusion, resveratrol could attenuate LPS-induced inflammation and oxidative stress in granulosa cells, and the underlying mechanisms may be related to the inhibitory effect of resveratrol on TLR2 expression in granulosa cells.

Exosomes of different origins have been found to be protective against ischemic-induced myocardial injury. This study examined the protective effects of circulating exosomes in the mice model of acute myocardial infarction (AMI) and explored the underlying molecular mechanisms. The effects of exosomes on myocardial injury were assessed in the AMI mice model. The in vivo studies showed that circulating exosomes reduced the infarcted size, improved the morphology of heart tissues and also reduced apoptosis of the heart tissues. In addition, the model mice showed an increase in the CD34 + /VEGFR2 + cell population and CD31, CXCR4 and CXCL12 expression after exosomes treatment. MiR-190a-3p was significantly down-regulated in the exosomes derived from the culture medium of hypoxia-treated human cardiomyocytes (HCMs). Further analysis revealed that miR-190a-3p could physically interact with CXCR4/CXCL12 by targeting the respective 3'UTRs. These exosomes could up-regulated CXCR4 and CXCL12 expression in the EPCs; in addition, miR-190a-3p mimics repressed CXCR4/CXCL12 expression in EPCs, while its inhibitor had opposite effects. The in vitro functional assays showed that miR-190a-3p overexpression suppressed the cell viability, proliferation, migration, adhesion and tube formation of EPCs; while miR-190a-3p inhibitor had the opposite effects; exosomes derived from the culture medium of hypoxia-treated HCMs exhibited similar actions of miR-190a-3p inhibitor. Moreover, miR-190a-3p was down-regulated in exosomes from serum in the AMI group when compared to that from sham group. Treatment with exosomes from serum in the AMI group promoted cell proliferation, migration, adhesion and tube formation of EPCs when compared to that in the sham group. More importantly, IT1t attenuated the enhanced effects of miR-190a-3p inhibition on EPC proliferation, migration, adhesion and tube formation. In conclusion, circulating exosomes exerted protective effects on myocardial injury in the AMI mice model, and down-regulation of miR-190a-3p in the circulating exosomes may exert protective effects against myocardial injury. Hypoxia induced the downregulation of miR-190a-3p in the culture medium of HCMs, and the mechanistic investigations indicated that exosomes of hypoxia-conditioned HCM culture medium promoted the cell viability, proliferation, migration, adhesion and tube formation of EPCs via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

Propionic acid (PA) predominantly accumulates in tissues and biological fluids of patients affected by propionic acidemia that may manifest chronic renal failure along development. High urinary excretion of maleic acid (MA) has also been described. Considering that the underlying mechanisms of renal dysfunction in this disorder are poorly known, the present work investigated the effects of PA and MA (1-5 mM) on mitochondrial functions and cellular viability in rat kidney and cultured human embryonic kidney (HEK-293) cells. Mitochondrial membrane potential (∆ψm), NAD(P)H content, swelling and ATP production were measured in rat kidney mitochondrial preparations supported by glutamate or glutamate plus malate, in the presence or absence of Ca²⁺. MTT reduction and propidium iodide (PI) incorporation were also determined in intact renal cells pre-incubated with MA or PA for 24 h. MA decreased Δψm and NAD(P)H content and induced swelling in Ca²⁺-loaded mitochondria either respiring with glutamate or glutamate plus malate. Noteworthy, these alterations were fully prevented by cyclosporin A plus ADP, suggesting the involvement of mitochondrial permeability transition (mPT). MA also markedly inhibited ATP synthesis in kidney mitochondria using the same substrates, implying a strong bioenergetics impairment. In contrast, PA only caused milder changes in these parameters. Finally, MA decreased MTT reduction and increased PI incorporation in intact HEK-293 cells, indicating a possible association between mitochondrial dysfunction and cell death in an intact cell system. It is therefore presumed that the MA-induced disruption of mitochondrial functions involving mPT pore opening may be involved in the chronic renal failure occurring in propionic acidemia.

Circular RNAs (circRNAs) play vital roles in human diseases, including acute kidney injury (AKI). In this paper, we focused on the effect of circRNA zinc finger protein 644 (circZNF644) on AKI cell model progression. qRT-PCR was conducted for the levels of circZNF644, ZNF644, miR-140-5p and mixed lineage kinase domain like pseudokinase (MLKL). RNase R assay, actinomycin D assay and subcellular fraction analysis were conducted to analyze the features of circZNF644. CCK-8 assay and EdU assay were used to explore cell proliferation. Flow cytometry analysis was conducted to analyze cell cycle and cell apoptosis. Western blot assay was executed for protein levels. ELISA was performed for the levels of inflammatory cytokines. The relationships among circZNF644, miR-140-5p and MLKL were analyzed by dual-luciferase reporter assay and RIP assay. CircZNF644 was upregulated in LPS-stimulated HK-2 cells. LPS-mediated inhibitory effects on cell proliferation and cell cycle and promotional effects on apoptosis and inflammation were reversed by circZNF644 knockdown. CircZNF644 directly interacted with miR-140-5p and MLKL was the target gene of miR-140-5p. The impact of circZNF644 knockdown on HK-2 cell injury was relieved by miR-140-5p inhibition. Moreover, miR-140-5p enhancement alleviated LPS-triggered HK-2 cell damage, while MLKL elevation reversed the effect. CircZNF644 knockdown protected HK-2 cells from LPS-induced injury by altering miR-140-5p/MLKL pathway, suggesting that circZNF644 may be a hopeful therapeutic target for AKI.