Biochemistry and Cell Biology最新文献

Antibiotics, specifically clindamycin (Clin), cause intestinal dysbiosis, reducing the microbiota with anti-inflammatory properties. Furthermore, Clin can induce alterations in the immune responses and oxidative stress. Lactoferrin, among other activities, participates in the maintenance of intestinal homeostasis and reduces dysbiosis induced by antibiotic treatment. The aim of this study was to analyze the effect of native and iron-saturated bovine LF in a murine model of dysbiosis induced by Clin. Six groups of male C57BL/6 mice were treated with saline (control), Clin, native lactoferrin (nLF), iron-saturated lactoferrin (sLF), nLF/Clin, or sLF/Clin. Oxidation caused in the intestinal cells of the ileum of animals subjected to different treatments was analyzed, focusing on lipid peroxidation and protein carbonyl content. The expression of inflammatory mediators was determined by qRT-PCR. Treatment with Clin did not modify lipid peroxidation, but significantly increased protein carbonyl levels up to almost 5-fold respect to the control, an effect that was reversed by orally administering sLF to mice. Furthermore, Clin increased the expression of interleukin-6 and TNF-α by 1- and 2-fold change, respectively. This effect was reversed by treatment with nLF and sLF, decreasing the expression to basal levels. In conclusion, this study indicates that lactoferrin can prevent some of the effects of Clin on intestinal cells and their associated immune system.

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.

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.

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.

Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible lung disease with high mortality and limited treatment options. While single-dose bleomycin-induced models are commonly used to investigate the pathogenesis of IPF, they fail to adequately replicate the complex pathological features in human patients, thereby hindering comprehensive investigations. Previous studies utilizing repetitive bleomycin injections have demonstrated a closer resemblance to human IPF pathology; however, the time- and resource-intensive nature of this approach presents significant drawbacks. Here, we propose a novel methodology involving twice-repeated oropharyngeal administration of bleomycin in mice, which closely mirrors the pathological manifestations observed in IPF patients. This model exhibited the honeycomb-like cyst formation, fibroblastic foci, bronchiolization of alveolar epithelium, emergence of metaplastic alveolar KRT5⁺ basal cells, and sustainability of these fibrotic phenotypes, thereby providing a robust model for IPF. Our findings establish a more efficient and translatable preclinical platform for investigating IPF pathogenesis and exploring potential therapeutic strategies.

Inflammatory bowel disease is a gut-brain axis disorder that comprises chronic inflammatory conditions affecting the gastrointestinal tract, where alterations in the mood of patients are common. Gut-brain axis is a bidirectional communication that link gut and brain. The close association between inflammatory bowel disease and neuroinflammation has far-reaching implications, as is increasingly recognized as a contributing factor to neuropsychiatric and neurodegenerative diseases. The increasing prevalence and high economic cost, together with the loss of life quality of people suffering from these diseases, point to the need to find alternatives to alleviate them. Exploring new therapeutic avenues prompts us to consider the potential benefits of milk fractions, taking advantage of the use of dairy by-products, such as whey and buttermilk. This study examines the impact of cow's whey- and buttermilk-based formulas supplemented with bovine lactoferrin and milk fat globule membrane on the expression of cytokines, as well as on the components of immune and serotonergic system of the brain in a murine model of dextran sodium sulfate-induced colitis. Our results show the potential of these dairy by-products, especially whey, as functional foods in ameliorating neuroinflammation and safeguarding the central nervous system function amid the neurological complications induced or concomitant with intestinal inflammatory processes.

This study mainly shows the role of endoplasmic reticulum transmembrane and coiled coil domains 1 (TMCO1) in the regulatory mechanism of hepatocellular carcinoma (HCC). Invasion and migration capacity were detected by Transwell and wound healing after TMCO1 and TOMM20 overexpression and knockdown, and mitochondrial function was detected through reactive oxygen species (ROS), mitochondrial permeability transition pore (mPTP), mitochondrial membrane potential (MMP), and ATP production. A model of subcutaneous tumor formation in nude mice was established to detect the effect of TMCO1 on tumor formation. The results showed that overexpression of TMCO1 significantly promoted HCC cell metastasis, promoted cell proliferation and ATP production, inhibited cell apoptosis, mPTP opening and ROS production, mediated the increase of MMP level and cytoskeletal remodeling. However, knocking down TMCO1 can have the opposite effect. More importantly, knocking down TOMM20 can block the regulation effect of TMCO1, and TOMM20 overexpression can alleviate the inhibitory effect of knocking down TMCO1 on the development of liver cancer cells. In animal models, knockdown of TMCO1 expression significantly inhibited the growth of subcutaneous implant tumors. This suggests that TMCO1 may be a potential and valuable therapeutic target for liver cancer.

Chromatin is dynamically regulated during development, where structural changes affect the transcription of genes required to promote different cell types. One of the chromatin regulatory factors responsible for transcriptional regulation during development is the SWItch/Sucrose Non-Fermentable (SWI/SNF) complex, an ATP-dependent chromatin remodeling factor conserved throughout eukaryotes. The catalytic subunit of this complex, BRG1, is shared in all three SWI/SNF complexes subfamilies and is essential for developing most cell lineages. Interestingly, many human developmental diseases have correlative or causative mutations in different SWI/SNF subunits. Many polybromo-associated BAF (pBAF) complex-specific subunit genetic alterations result in developmental failures in tissue-specific ways. This observation suggests that the pBAF complex plays a vital role in development and differentiation, and studying the pBAF complex may provide an opportunity to better understand gene regulation during development. In this mini-view, we will focus on the functions of pBAF-specific subunits and their influence on the development of various cell and tissue types by regulating developmental gene expression.