BioFactors最新文献

Nootkatone, a valuable sesquiterpene with broad bioactivities and application potential, faces yield limitations in microbial synthesis due to metabolic and enzymatic inefficiencies. In this study, we present an advanced strategy combining metabolic engineering and deep learning-guided enzyme design to optimize nootkatone production in Pichia pastoris. By systematically modifying the mevalonate pathway, optimizing cofactor supply, and minimizing competing metabolic pathways, a robust yeast strain producing 702.15 mg/L valencene was developed. To facilitate the efficient conversion of valencene to nootkatone, we applied ancestral sequence reconstruction (ASR) to identify hotspot amino acid residues, guiding the design of a variant library. The deep learning model DLKcat was then used to conduct virtual saturation mutagenesis screening on library sites, predicting their enzyme turnover number (k_cat). The engineered cytochrome P450 (HPO) variant H54A exhibited the highest activity, with catalytic performance 2.3 times that of the initial. Furthermore, the implementation of intermittent feeding fermentation significantly elevated the final nootkatone yield to 3365.36 mg/L, the highest reported to date. This study provided a green platform for an alternative sustainable access of high-value nootkatone, and exemplifies the potential of machine learning in optimizing metabolic pathway enzymes for efficient biosynthesis of other bioactive terpenoids in microbial systems.

Colorectal cancer (CRC) onset is closely linked to dysregulated Notch signaling, particularly involving receptors like Notch1 and Notch3, and ligands such as Jagged1 (Jag1), which are overexpressed in aggressive subtypes. To address the need for a quantitative assessment of Notch expression in clinical settings, we developed a luminescent recombinant probe (Jag1-Fluc) by fusing the extracellular domain of a high-affinity Jag1 mutant with red-emitting firefly luciferase. The Jag1-Fluc probe can bind to Notch, thus correlating the intensity of emitted light with the concentration of Notch in the sample. In cell-free assays, Jag1-Fluc demonstrated a linear luminescent signal across different concentrations (detection limit: 0.20 ± 0.03 μg/mL). When applied to living and fixed human colorectal cancer cells, the probe showed a dose-dependent light emission (5–50 μg/mL), confirming its ability to bind endogenous Notch receptors. Competitive binding assays using soluble human Jag1 chimera demonstrated concentration-dependent signal inhibition (IC₅₀ = 0.55 ± 0.06 μg/mL), validating probe specificity. Notably, in a small cohort of human biopsies, Jag1-Fluc enabled stratification of Notch expression, with luminescence intensity progressively increasing from hyperplastic polyps to low- and high-grade adenomas. These findings reinforce prior evidence linking Jag1 overexpression to CRC progression. The assay's simplicity and sensitivity highlight its potential for early CRC screening, paving the way for personalized medicine by enabling tailored therapeutic monitoring and strategies based on Notch signaling profiles. This approach potentially enhances treatment efficacy and reduces side effects, representing a valuable tool for precision oncology.

Cancer is one of the major public health challenges worldwide, and the STAT3 signaling pathway is recognized as one of the most important signaling pathways in the progression of this disease. This pathway can increase the survival and proliferation of cancer cells and their resistance to treatment by regulating lipid and carbohydrate metabolism, apoptosis, and inflammatory processes. Therefore, STAT3 inhibition is considered an effective therapeutic approach in the fight against cancer. Two main strategies (direct and indirect) have been considered to inhibit this protein, with direct inhibition being more effective due to its more specific properties. Extensive research is also underway to design and develop effective inhibitors for STAT3, and in this regard, SH2 domain inhibitors have reached clinical trial phases.

Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by amyloid-β (Aβ) aggregation, oxidative stress, and neuroinflammation, remains a significant global health challenge. This study investigates the therapeutic potential of flavonols—quercetin, kaempferol, myricetin, and fisetin—in targeting Aβ aggregation and mitigating AD pathology through diverse molecular mechanisms. Our findings reveal that flavonols effectively inhibit Aβ oligomerization and fibril formation, reduce oxidative stress via Nrf2/HO-1 pathway activation, and suppress neuroinflammation by modulating microglial polarization. Additionally, these compounds enhance mitochondrial function, promote autophagy-mediated clearance of Aβ aggregates, and regulate key enzymes such as β-secretase (BACE1) and α-secretases (ADAM10/17), favoring non-amyloidogenic pathways. Quercetin demonstrated neuroprotective effects by activating TrkB signaling, reducing tau phosphorylation, and enhancing synaptic plasticity. Kaempferol prevented Aβ-induced apoptosis via the ER/ERK/MAPK pathway and inhibited acetylcholinesterase activity, improving cognitive outcomes. Myricetin ameliorated mitochondrial dysfunction and oxidative damage through GSK3β/ERK2 signaling modulation and showed enhanced brain bioavailability when delivered via nanostructured lipid carriers. Fisetin reduced Aβ burden by upregulating neprilysin expression, suppressed neuroinflammation, and improved synaptic function by restoring synaptic protein levels. Overall, flavonols exhibit multi-targeted therapeutic potential against AD by addressing its complex pathogenesis. Their ability to cross the blood–brain barrier and low toxicity profiles position them as promising candidates for further clinical development. This study underscores the potential of flavonols as natural agents for AD treatment and highlights their role in advancing multi-mechanistic therapeutic strategies.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Spindle- and kinetochore-associated complex 1 (SKA1) participates in the regulation of mitosis, playing an essential role in regulating cancer progression. Therefore, this study aims to explore the effects of knocking down SKA1 on HCC. The bioinformatics analysis approaches were adopted to predict SKA1 expression in HCC, the role of SKA1 on the survival rate and prognosis of HCC patients, and the associations between SKA1 expression and gene mutation and immune cell infiltration. The single-cell transcriptome sequencing analysis was employed to explore the cell–cell communications and molecular interactions. The CCK-8, wound healing, Transwell, flow cytometry, and qRT-PCR approaches were used to determine the cell viability, invasion, migration, cell cycle, apoptosis, and SKA1 mRNA expression level of SMMC7721 cells. The tumor volume and weight were measured. The Western blot was applied to determine the protein expression levels of SKA1, survivin, Bax, Bad, Bcl-2, caspase-3, and caspase-9 in SMMC7721 cells and tumor tissue. The bioinformatics analysis results indicated that highly expressed SKA1 was related to a low survival rate and poor prognosis of HCC patients and was involved in the TP53 mutation and multiple immune cell infiltrations. The single-cell transcriptome sequencing analysis affirmed that malignant cells were associated with hepatocytes, ILC, and granulocytes. Meanwhile, various pathways and ligand-receptor pairs were enriched in the cell subpopulation with high SKA1 expression, especially for the Protease-Activated Receptors (PARs) pathway and MDK-SDC1 pair associated with the apoptosis signaling. Knocking down SKA1 reduced the cell viability, invasion, and migration, arrested the cell cycle in the S period, promoted the apoptosis in vitro, decreased the tumor volume and weight in vivo, and down-regulated the survivin and Bcl-2 protein expression levels and up-regulated the caspase 3, caspase 9, Bax, and Bad in vivo and in vitro. Taken together, knocking down SKA1 inhibited HCC progression by promoting the apoptosis signaling pathway.

A plant-based diet is known to be nutrient-dense and rich in fibers, healthy fats, proteins, vitamins, and minerals. A diet rich in plant-based foods may help reduce the risk of chronic diseases such as cardiovascular disease and diabetes. As consumers become more health conscious, there is a growing interest in plant-based diets. In addition to providing essential nutrients, some food proteins may provide additional health benefits, as plant proteins are broken down into bioactive peptides during gastrointestinal digestion, often in dependence on previous processing. Bioactive peptides have several important functions in the body, including antioxidant, antimicrobial, immunomodulatory, and anti-hypertensive effects. To date, several reviews have provided an overview of the generation of bioactive peptides and their associated biological activities and putative health benefits in a range of animal-based foods, but information on plant-based foods is fragmented. We then systematically reviewed the existing literature reporting the release of bioactive peptides from plant-based food products and ingredients after in vitro digestion according to the INFOGEST protocol. The results reported in this review highlight that most of the bioactive peptides of plant origin exhibited antioxidant, anti-hypertensive, and anti-diabetic activity. The relationship between the structure and functionality of peptides and the major gaps in bioactive peptide research were also discussed, to focus on these aspects in future research. This may lead to a better understanding of the behavior of plant proteins in the human gastrointestinal tract, enhancing their contribution as sources of bioactive peptides.

Endoplasmic reticulum (ER) stress is a fundamental process that profoundly influences immune cell function and plays a critical role in the development and progression of various physiological and pathological conditions. Understanding the underlying mechanisms of ER stress and its implications for cellular function and disease pathogenesis is of paramount importance in developing targeted therapeutic interventions. Dexmedetomidine, an alpha-2 adrenergic agonist primarily used as a sedative, has emerged as a potential modulator of ER stress. This review aims to explore the impact of Dexmedetomidine on ER stress within immune cells and its potential therapeutic implications. Dexmedetomidine exhibits the remarkable ability to inhibit the activation of ER stress pathways, preserve protein synthesis, and suppress apoptosis mediated by ER stress markers. Furthermore, Dexmedetomidine exerts regulatory effects on immune cells and inflammation by reducing the production of proinflammatory cytokines and modulating immune functions. These compelling findings suggest that Dexmedetomidine holds significant promise as a valuable therapeutic tool for conditions characterized by dysregulated ER stress and immune dysfunction.