Biochemistry and Cell Biology最新文献

Parkinson's disease (PD) is one of the most commonly affecting neurodegenerative disorder prevalent in our society. The inherited autosomal recessive PD/parkinsonism occurs due to mutations in six genes including, the gene for PTEN (phosphatase and tensin homologue)-induced putative kinase1 (PINK1). The pathophysiology and development of disorders associated with the mitochondria occur simultaneously with the dysregulation of PINK1. The activation/regulation of PINK1 through autophagy regulators can reduce PD condition. This study focused on exploring the possibility of 2062 phytochemicals as autophagy regulators. In silico docking and simulation studies are performed to identify their binding with the PINK1. Our studies highlight the phytochemicals like Proanthocyanidin A-6, Withanolide Q, and pseudo-ginsenoside F11 that showed higher binding energy and stable interactions during the course of simulation. This study opens avenues for testing these compounds as positive modulators of PINK1 kinase activity using in vitro and in vivo methods and use of these compounds as phytotherapeutic for the treatment of PD.

Human zyxin is a key component of the focal adhesion complex, playing a role in mediating cell-cell adhesion and cytoskeletal dynamics. Moreover, zyxin shuttles between the cytoplasm and the nucleus, where it contributes to regulating gene expression. Although identified over 30 years ago, zyxin's nuclear functions, particularly in relation to cancer, remain largely unexplored. In this study, we profiled zyxin binding to chromosomal DNA using metastatic prostate carcinoma PC3M cells as a model. Our ChIP-Seq results revealed that zyxin binds to chromosomal DNA, with mitochondrial pseudogenes as the primary targets. Furthermore, we demonstrated that the LIM domains of zyxin are sufficient for DNA binding and that zyxin knockdown leads to transcriptional changes in mitochondrial pseudogenes. Additionally, zyxin knockdown impacted several other genes associated with mitochondrial integrity and apoptosis, resulting in disturbances in MTCO2P2 RNA localization, mitochondrial membrane potential, increased reactive oxygen species, alterations in the cell cycle, and progression towards apoptosis. Overall, our work shows that zyxin directly interacts with nuclear DNA and regulates the transcription of mitochondrial pseudogenes, emphasizing its role in modulating mitochondrial function.

Immune checkpoint inhibitors (ICIs)-related myocarditis, a severe complication characterized by elevated cardiac troponin I, poses significant clinical challenges in distinguishing it from acute myocardial infarction (AMI). Our study aimed to identify plasma protein biomarkers that differentiate ICIs-myocarditis from AMI. Plasma samples from 5 ICIs-myocarditis patients (with paired baseline and diagnosis samples) and 5 angiography-confirmed AMI patients, matched for age, gender, smoking history, and pre-existing heart disease, were analyzed using label-free liquid chromatography-mass spectrometry proteomics. A total of 1521 plasma proteins were identified, with 1325 quantifiable. Proteomic profiling revealed differentially expressed proteins (DEPs) in ICIs-myocarditis associated with myocardial contraction, proteasome activity, NF-κB signaling, immunoregulation, and amino acid metabolism. Through validation in animal models of ICIs-myocarditis and AMI, two plasma proteins-MYOM3 (myomesin 3) and galectin-1 (LGALS1)-were identified as potential biomarkers linked to the onset of ICIs-related myocarditis. Further validation using expanded clinical cohorts confirmed their differential expression. These findings highlight MYOM3 and galectin-1 as promising biomarkers for distinguishing ICIs-related myocarditis from AMI, providing insights for clinical diagnosis and mechanistic research into immune-related cardiotoxicity.

Methyl CpG binding protein 2 (MeCP2) is a chromatin-associated protein that remains enigmatic despite more than 30 years of research, primarily due to the ever-growing list of its molecular functions, and, consequently, its related pathologies. Loss of function MECP2 mutations cause the neurodevelopmental disorder Rett syndrome (RTT); in addition, dysregulation of MeCP2 expression and/ or function are involved in numerous other pathologies, but the mechanisms of MeCP2 regulation are unclear. Advancing technologies and burgeoning mechanistic theories assist our understanding of the complexity of MeCP2 but may inadvertently cloud it if not rigorously tested. Here, rather than focus on RTT, we examine relatively underexplored aspects of MeCP2, such as its dosage homeostasis at the gene and protein levels, its controversial participation in phase separation, and its overlooked role in depression and oxidative stress. All these factors may be essential to understanding the full scope of MeCP2 function in healthy and diseased states, but are relatively infrequently studied and require further criticism. The aim of this review is to discuss the esoteric facets of MeCP2 at the molecular and pathological levels and to consider to what extent they may be necessary for general MeCP2 function.

Prostate cancer (PCa) is a complex disease with diverse molecular alterations. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that exhibits pleiotropic roles in PCa, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent ligand for AhR. While targeting ferroptosis is an innovative PCa therapeutic strategy, the impact of AhR on this process remains unclear. This study aimed to investigate the influence of AhR on lipid peroxidation and ferroptosis. Results showed that TCDD activated AhR, as evidenced by increased CYP1A1 expression, leading to reduced cell viability. TCDD caused mitochondria shrinkage, decreased the GSH/GSSG ratio, and elevated the MDA levels and lipid peroxidation. Interestingly, AhR knockdown reversed these effects, similar to the action of ferroptosis inhibitors. Mechanistically, TCDD suppressed nuclear receptor subfamily 4 group A member 1 (NR4A1) expression, in part due to AhR activation. This suppression subsequently led to a reduction in the expression of the NR4A1 downstream target stearoyl-CoA desaturase 1 (SCD1). NR4A1 overexpression counteracted the effects of TCDD. In vivo, TCDD activated AhR, downregulated NR4A1 and SCD1 expression, induced mitochondria shrinkage, and increased the MDA and 4-hydroxynonenal (4-HNE) levels. In summary, TCDD promotes ferroptosis in androgen-dependent PCa via inhibiting the NR4A1/SCD1 axis, in part dependent on AhR activation.

Bovine lactoferrin (bLf) confers significant functional benefits for human health, but low concentrations in milk and high cost of commercial production limit availability and thus product application. Precision fermentation offers a solution to increase availability of biosimilar recombinant bLf (rbLf) thereby opening new opportunities for this high-value ingredient. To comply with regulatory requirements, we aimed to establish that rbLf from Komagataella phaffii is substantially similar to native bLf in structure and key functions. Intact mass analysis showed a molecular weight of 84 kDa for rbLf, comparable to 82-83 kDa of bLf. LC-MS N-linked glycan profiling revealed predominantly high-mannose-based glycans on rbLf, similar to ∼50% of bLf glycans. The isoelectric point and core amino acid sequence of rbLf and bLf are identical. rbLf retains the functional ability to bind and release iron, bind to intestinal Lf receptors, increase epithelial cell growth (>120% of control, P < 0.0001), reduce enteropathogenic Escherichia coli growth (>50% reduction, P < 0.0001), bind lipopolysaccharide (LPS) (+4-fold, P < 0.001), and antagonize LPS-induced toll-like receptor 4 activity (>40% reduction, P < 0.0001). These results demonstrate similarity of rbLf in structure and function to native bLf, supporting the effective application for expanded market opportunities for infant and adult health.

Fusarium graminearum FgSte2 and FgSte3 are G-protein-coupled receptors (GPCRs) shown to play roles in hyphal chemotropism and fungal plant pathogenesis in response to activity arising from host-secreted peroxidases. Here, we follow up on the observation that chemotropism is dependent on both FgSte2 and FgSte3 being present; testing the possibility that this might be due to formation of an FgSte2-FgSte3 heterodimer. Bioluminescence resonance energy transfer (BRET) analyses were conducted in Saccharomyces cerevisiae, where the addition of horse radish peroxidase (HRP) was found to increase the transfer of energy from the inducibly expressed FgSte3-Nano luciferase donor, to the constitutively expressed FgSte2-yellow fluorescent protein (YFP) acceptor, compared to controls. A partial response was also detected when an HRP-derived ligand-containing extract was enriched from F. graminearum spores and applied instead of HRP. In contrast, substitution with pheromones or an unrelated bovine GPCR, rhodopsin-YFP used as acceptor, eliminated all BRET responses. Interaction results were validated by affinity pulldown and receptor expression was validated by confocal immunofluorescence microscopy. Taken together these findings demonstrate the formation of HRP and HRP-derived ligand stimulated heterodimers between FgSte2 and FgSte3. Outcomes are discussed from the context of the roles of ligands and reactive oxygen species in GPCR dimerization.

Our previous study showed antitumor activity of the complex formed by iron-free recombinant human lactoferrin (apo-recHLF) and oleic acid (OA) (1:8 molar ratio) in a model of murine hepatoma 22a inoculated to C3HA mice. Taken alone, apo-recHLF was less efficient; i.e., the tumor growth index was 0.14 for recHLF-8OA and 0.63 for recHLF as compared with 1.0 in the control animals. In the present study, we evaluated antitumor activity of iron-saturated recHLF per se and of the complexes formed by OA with apo-recHLF and holo-recHLF. Balb/c mice with solid myeloma Sp2/0 were subjected to the 10-day treatment with daily intraperitoneal (i/p) injections of 10 mg iron-saturated recHLF with OA (1:8) per animal (0.4 g/kg). In 15 days, the tumor growth was substantially inhibited. Mean tumor mass was 93% lower as compared with the control value (p < 0.01). I/p injections of apo-recHLF/OA complex did not inhibit the tumor growth. Holo-recHLF used without OA had less pronounced antitumor effect as compared with their complex.