Advanced biology最新文献

Physiological aging is accompanied by structural and molecular changes in the brain, with varying degrees in different brain areas, and is considered one of the major risk factors for neurodegenerative diseases. Thus, the present study focuses on elucidating age-related changes in the substantia nigra pars compacta (SNpc), a brain region particularly vulnerable in Parkinson's disease. Here, the aim is to gain a spatially resolved view of aging-dependent alterations to conclude early processes potentially involved in neurodegeneration. Neuromelanin granules and SNpc tissue are isolated from tissue samples of young and elderly individuals via laser microdissection and measured by mass spectrometry to ascertain changes in protein expression in response to age. The findings include the identification of reduced levels of proteins involved in dopaminergic neurotransmission, either suggesting a specific loss of dopaminergic neurons or a reduction in metabolic activity. Furthermore, increased neuroinflammation is observed in elderly individuals and alterations in vesicular trafficking as well as mitochondrial proteins. Consequently, this exploratory study suggests that alterations causing known pathomechanisms of Parkinson's disease are already occurring in the physiological aging process. Since aging is still the most important risk factor for neurodegenerative diseases, these findings strengthen the necessity for studying age-related changes.

Signal Transducer and Activator of Transcription 3 (Stat3) acts as a central transcriptional modulator coordinating cellular proliferation, survival, apoptosis, vascularization, immune regulation, and migratory processes. Human Stat3 deficiency triggers Hyper-IgE syndrome, associated with immune dysregulation, osseous defects, and dental malformations. This study employs genetically engineered murine models to dissect Stat3's mechanistic role within mesenchymal progenitor cells during molar root formation and periodontal tissue maturation. Conditional Stat3 knockout mice (Prx1-Cre; Stat3^f/f) are generated. Comparative assessments of mandibular first molar root development between Stat3 CKO and wild-type cohorts are performed through histomorphometric evaluation, micro-computed tomography, cellular proliferation assays (Ki67/BrdU), and transcriptome sequencing. Stat3 ablation causes marked morphological defects in first molars, featuring reduced root length and elevated crown-root proportion. The periodontal ligament (PDL) at the distal root exhibits diminished width in mutants. Alveolar bone displays suppressed expression of osteogenic markers (Runx2, Col1a1, Ocn), accompanied by decreased Ki67⁺ and BrdU⁺ cell populations in the PDL. Stat3 critically regulates mandibular first molar and alveolar bone morphogenesis. Conditional ablation of Stat3 disrupts the osteogenic capacity of Prx1⁺ mesenchymal progenitors, as evidenced across in vivo and in vitro models.

Esophageal cancer is a major disease that seriously threatens human health. Ribosomal RNA biogenesis is implicated in tumorigenesis, while the small nucleolar RNAs (snoRNAs) are responsible for post-transcriptional modifications of ribosomal RNAs during biogenesis, which are identified as potential markers of various cancers. The clinical significance, biological behavior, and potential molecular mechanism of the nucleolar small nuclear ribonucleoprotein RRP9 in esophageal squamous cell carcinoma (ESCC), which is a major pathological type of esophageal cancer, are investigated in this study. It is found that RRP9 is abnormally highly expressed in ESCC tissues and is closely associated with poor prognosis. Furthermore, it is found that RRP9 could regulate the cell cycle protein-dependent kinase CDK1 to promote ESCC progression in vitro and in vivo. Mechanistically, RRP9 promotes ESCC progression through enhancing the E2F1-mediated transcriptional regulation of CDK1. Collectively, the results defined RRP9 as an important tumor driver in ESCC that acted by activating oncogenic signaling by the E2F1-CDK1 pathway, and suggested RRP9 as a candidate therapeutic target for ESCC.

The mechanisms underlying leaf unfolding remain largely speculative and are often inferred from mathematical models. Peltate leaves, unlike typical foliage leaves, frequently emerge in a “rolled-up” state. This study investigates mechanisms related to the unrolling process in the peltate species Syngonium podophyllum by analyzing anatomical and morphological changes and quantifying forces that arise during unrolling. Leaf unrolling in S. podophyllum appears to be primarily driven by cell expansion, particularly in the upper epidermis, with cell turgor playing an important role in leaf development and unrolling. Considering leaf properties such as cell dimensions and leaf radius of curvature, this work proposes a mathematical model to further characterize the unrolling process. The model provides satisfactory predictions of curvature variations, highlighting its potential for other plant movements involving dynamic curvature changes.

Growth factors play a crucial role in regulating cellular processes such as proliferation, differentiation, and survival. Their activities are tightly modulated to ensure proper physiological functioning, with dysregulation often contributing to disease pathogenesis. Among these, the insulin-like growth factor (IGF) system that encompasses IGF-1 and IGF-receptor binding proteins is pivotal in maintaining overall cellular health by regulating growth, repair, and metabolic regulation. Capitalizing on its pro-mitogenic effects, translational studies have focused efforts on developing therapeutics based on IGF-1 for age-related muscle loss, metabolic disorders, or cardiovascular diseases. Mimetic peptide design has emerged as an innovative approach to overcoming limitations of direct IGF-1 therapy, focusing on structural optimization to enhance bioavailability, stability, and receptor specificity. Herein, the development of IGF-1 mimics and their potential clinical applications are reviewed. Their design and molecular properties, including structural considerations and mechanisms of action, are described. In vitro and in vivo approaches analyzed to provide insights into their pharmacokinetics, therapeutic efficacy, and safety profiles in animal models will be delved into. These preclinical studies shed light on the advantages of IGF-1 mimics, such as bioavailability, stability, and delivery, as well as the limitations, including potential immunogenicity.

Antimicrobial Photodynamic Therapy (aPDT) has become a potential alternative for treating multidrug-resistant bacterial skin infections, such as those caused by methicillin-resistant Staphylococcus aureus (MRSA), which are at high risk in aging individuals. One of the main components of aPDT is an agent known as a photosensitizer (PS). Some plants with high flavonoid content are reported as PS. In the genus Passiflora, flavonoids are predominant, but their photosensitizing activity has yet to be described. This study investigates the photosensitizing potential of extracts from Passiflora edulis, Passiflora alata, and Passiflora cincinnata. The butanolic fraction of P. cincinnata undergoes in vivo evaluation against intradermal MRSA infection in a senescent murine model (C57BL/6). In vitro assays determine the photoactivatable concentrations and their cytotoxicity. In vivo, MRSA-infected mice are divided into control, P. cincinnata-treated, and aPDT-treated groups. Subsequent assessments include cytokine levels, bacterial load, and cellular infiltrate in the ear. The P. cincinnata-treated group exhibits improved bacterial control, reduced leukocyte infiltration, and less weight loss. The aPDT group demonstrates a unique cytokine correlation profile, featuring more negative correlations among pro-inflammatory cytokines and interleukin-10. P. cincinnata emerges as an effective photosensitizer for aPDT in a senescent model and highlights the potential of underexplored plant-derived photosensitizers.

With the growing global threat of mosquito-borne diseases, there is an urgent need for faster, automated methods to assess disease load in mosquitoes and predict outbreaks. Current surveillance relies on manual mosquito traps and labor-intensive lab tests like polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), which are time-consuming and resource-intensive. In this study, machine learning algorithms are applied to detect dengue-infected mosquitoes based on their 3D flight patterns. Using a convolutional neural network (CNN) and cubic spline interpolation, mosquito flight trajectories are tracked, followed by classification with models including CNN, eXtreme Gradient Boosting (XGBoost), Adaptive Boosting (AdaBoost), Random Forest, Decision Tree, Naive Bayes, Logistic Regression, Multi-Layer Perceptron (MLP), and a hybrid CNN + XGBoost model. The 5-fold cross-validation results showed that XGBoost achieved the highest mean accuracy (81.43%), while Random Forest has shown the best mean F1 Score (82.80%). Some validation folds demonstrated outstanding performance, with AdaBoost reaching 95.85% accuracy and Random Forest achieving 97.77% recall in Fold 1. The study also analyzed the impact of flight sequence size on models' performance, observing that longer sequences provided more accurate predictions. This approach offers a faster and more efficient method for assessing infection status, supporting real-time vector monitoring, and improving early disease outbreak detection.

Accurate detection of heparin-induced thrombocytopenia (HIT) antibodies is crucial for diagnosing and managing thrombotic events. Conventional immunoassays, however, often lack specificity and require confirmatory testing with fresh human platelets. To address this limitation, we optimized our previously developed cell-based enzyme-linked immunosorbent assay (ELISA) for improved HIT detection under various experimental conditions. Platelet factor 4 was immobilized on breast cancer cells (MDA-MB-231) to capture monoclonal HIT-like (KKO) and non-HIT (RTO) antibodies, which served as models to evaluate assay performance under different pH levels, ionic strengths (NaCl), and fixation methods (ethanol, paraformaldehyde, glutaraldehyde). To identify the most suitable substrate, additional cancer cell lines (HCT-116, MCF-7, HepG2) were tested under live and fixed conditions, with selected conditions validated using human HIT sera. Optimal detection tested with monoclonal antibodies was achieved using 50 mM NaCl and 4% paraformaldehyde fixation. Notably, live MDA-MB-231 and HCT-116 cells demonstrated superior sensitivity and specificity compared to fixed cells. Furthermore, these cell lines enable the efficient detection of HIT antibodies using flow cytometry, a robust and platelet-free diagnostic method. Our findings establish live MDA-MB-231 and HCT-116 cells as highly promising platforms for clinical applications in HIT antibody detection.

The S-phase kinase-associated protein 1 (Skp1)-Cullin-F-box protein E3 ligase adaptor F-box-only protein 31 (FBXO31) regulates genomic stability and cell signaling in normal, genotoxic, and tumor cells by recognizing and ubiquitinating multiple downstream substrates. The stability and role of FBXO31 may be regulated by specific residual modification. In this study, five FBXO31 phosphorylation sites are identified in HEK293T cells using biochemical and biological techniques. Liquid chromatography–tandem mass spectrometry identifies phosphorylated residues, including threonine-28 and -37 and serine-33, -400, and -523. The PyMOL crystal structure reveals the location of these residues on FBXO31 and assesses whether they interact with the reported kinases. Western blotting and fluorescence-activated cell sorting demonstrate that the phosphorylation of Thr-37 and Ser-523 contributes to FBXO31 protein stabilization, which is further confirmed by cycloheximide experiments. The regulatory roles of Thr-37 and Ser-523 in FBXO31 stability are associated with variations in phosphorylation levels and degradation pathways. These results demonstrate that phosphorylation regulates FBXO31 turnover, and phosphorylation at Thr-37 or Ser-523 may help identify upstream kinases and enhance the understanding of the physiological role of FBXO31.

Mesenchymal stem cells (MSCs) migrate to injured tissues, aiding tissue repair, remodeling, and wound healing. As tumors are often considered to have traits of “injured tissues,” MSCs are recruited to tumor microenvironments where they can have pro- and antitumorigenic influences. This study assesses whether human mesenchymal stem cells (hMSCs) of shared ancestry exhibit similar tumorigenic properties. Bone marrow-derived (hBM-MSCs) and umbilical cord-derived (hUC-MSCs) MSCs embedded in collagen are cultured in conditioned media from lung adenocarcinoma (A549) cells to mimic the extracellular matrix and soluble cues of the cancer microenvironment. Cell viability, proliferation, and immunofluorescence analyses evaluate MSC behavior under these conditions. Further, A549 cells are exposed to conditioned media from cancer-stimulated MSCs to simulate indirect co-culture, and their response is assessed through viability, immunofluorescence, and flow cytometric analysis. Results show increased viability and proliferation of hBM-MSCs, morphological changes, and elevated alpha-smooth muscle actin expression, suggesting a transition toward cancer-associated fibroblasts. In contrast, hUC-MSCs display reduced viability and no morphological alterations. Conditioned media from cancer-exposed hUC-MSCs induce apoptosis in A549 cells, whereas hBM-MSCs support A549 growth. These findings demonstrate that, despite their common origin, hUC-MSCs and hBM-MSCs exhibit opposing responses to tumor cues and influence lung cancer cell behavior differently.