Cells最新文献

Chemical modifications of cellular RNAs play key roles in gene expression and host defense. The cap-adjacent N⁶,2'-O-dimethyladenosine (m⁶Am) is a prevalent modification of vertebrate and viral mRNAs and is catalyzed by the newly discovered N⁶ methyltransferase PCIF1. However, its role in gene expression remains unclear due to conflicting reports on its effects on mRNA stability and translation. In this study, we investigated the impact of siRNA-mediated transient suppression of PCIF1 on global mRNA expression in HeLa cells. We identified a subset of differentially expressed genes (DEGs) that exhibited minimal overlap with previously reported DEGs. Subsequent validation revealed that PCIF1 positively and negatively regulates RAB23 and CNOT6 expression, respectively, at both the mRNA and protein levels. Mechanistic analyses demonstrated that PCIF1 regulates the stability of these target mRNAs rather than their transcription, and rescue experiments confirmed the requirement of PCIF1's methyltransferase activity for these regulations. Furthermore, MeRIP-qPCR analysis showed that PCIF1 suppression significantly reduced the m⁶A levels of RAB23 and CNOT6 mRNAs. These findings suggest that PCIF1 regulates the stability of specific mRNAs in opposite ways through m⁶A modification, providing new insights into the role of m⁶Am in the regulation of gene expression.

Flow cytometry facilitates the detection of multiple cell parameters simultaneously with a high level of resolution and throughput, enabling in-depth immunological evaluations. High data resolution in flow cytometry depends on multiple factors, including the concentration of reagents used in the staining protocol, and reagent validation and titration should be the first step in any assay optimization. Titration is the process of finding the concentration of the reagent that best resolves a positive signal from the background, with the saturation of all binding sites, and minimal antibody excess. The titration process involves the evaluation of serial reagent dilutions in cells expressing the antigen target for the tested antibody. The concentration of antibody that provides the highest signal to noise ratio is calculated by plotting the percentage of positive cells and the intensity of the fluorescence of the stained cells with respect to the negative events, in a concentration-response curve. The determination of the optimal antibody concentration is necessary to ensure reliable and reproducible results and is required for each sample type, reagent clone and lot, as well as the methods used for cell collection, staining, and storage conditions. If the antibody dilution is too low, the signal will be too weak to be accurately determined, leading to suboptimal data resolution, high variability across measurements, and the underestimation of the frequency of cells expressing a specific marker. The use of excess antibodies could lead to non-specific binding, reagent misuse, and detector overloading with the signal off scale and higher spillover spreading. In this publication, we summarized the titration fundamentals and best practices, and evaluated the impact of using a different instrument, sample, staining, acquisition, and analysis conditions in the selection of the optimal titer and population resolution.

Motor ability decline remains a major threat to the quality of life of the elderly. Although the later stages of aging co-exist with degenerative pathologies, the long process of aging is more complicated than a simple and gradual degeneration. To combat senescence and the associated late-stage degeneration of the neuromuscular system, it is imperative to examine changes that occur during the long process of aging. Prior to late-stage degeneration, age-induced changes in the neuromuscular system trigger homeostatic plasticity. This unique phenomenon may be important for the maintenance of the neuromuscular system during the early stages of aging. In this review, we will focus on age-induced changes in neurotransmission at the neuromuscular junction, providing the potential mechanisms responsible for these changes. The goal is to highlight these key elements and their role in regulating neurotransmission, facilitating future research efforts to combat late-stage degeneration in the neuromuscular system by preserving the functional and structural integrity of these elements prior to the late stage of aging.

This study evaluated ethosomes as a novel nanodelivery system for nutlin-3a, a known MDM2 inhibitor and activator of the p53 pathway, to improve nutlin-3a's poor solubility, limiting its bio-distribution and therapeutic efficacy. The potential of nutlin-3a-loaded ethosomes was investigated on two in vitro models of melanoma: the HT144 cell line p53^wild-type and the SK-MEL-28 cell line p53^mutated. Nutlin-3a-loaded ethosomes were characterized for their physicochemical properties and used to treat melanoma cells at different concentrations, considering nutlin-3a solution and empty ethosomes as controls. The biological effects on cells were evaluated 24 and 48 h after treatment by analyzing the cell morphology and viability, cell cycle, and apoptosis rate using flow cytometry and the p53 pathway's activation via Western blotting. The results indicate that ethosomes are delivery systems able to maintain nutlin-3a's functionality and specific biological action, as evidenced by the molecular activation of the p53 pathway and the biological events leading to cell cycle block and apoptosis in p53^wild-type cells. Nutlin-3a-loaded ethosomes induced morphological changes in the HT144 cell line, with evident apoptotic cells and a reduction in the number of viable cells of over 80%. Furthermore, nutlin-3a-loaded ethosomes successfully modulated two p53-regulated proteins involved in survival/apoptosis, with up to a 2.5-fold increase in membrane TRAIL-R2 and up to an 8.2-fold decrease in Notch-1 (Notch intracellular domain, NICD) protein expression. The expression of these molecules is known to be altered or dysfunctional in a large percentage of melanoma tumors. Notably, ethosomes, regardless of their nutlin-3a loading, exhibited the ability to reduce HT144 melanoma cellular migration, as assessed in real time using xCELLigence, likely due to the modification of lipid rafts, suggesting their potential antimetastatic properties. Overall, nutlin-3a delivery using ethosomes appears to be a significantly effective means for upregulating the p53 pathway and downregulating active Notch-1, while also taking advantage of their unexpected ability to reduce cellular migration. The findings of this study could pave the way for the development of specific nutlin-3a-loaded ethosome-based medicinal products for cutaneous use.

(Background) Cancer-associated fibroblasts (CAFs) are major cancer stromal components. CAFs have diverse functions and cell origins. Podoplanin (PDPN), a lymphatic vessel marker, is also a CAF marker in certain cancers. On daily diagnosis of early colorectal carcinoma (CRC), PDPN upregulation in the stroma is often encountered, suggesting PDPN-positive CAFs have emerged. However, PDPN-positive CAFs in early CRC have not been studied well. (Methods) On immunohistochemistry, PDPN expression in the lamina propria or stroma of adenomas, early CRCs, and neuroendocrine tumors, their normal neighbors, and non-neoplastic colorectal lesions were compared. Single-cell RNA sequencing (scRNA-seq) of CRC was used to explore PDPN^high CAFs' cell origins. (Results) Reticular cells or pericryptal fibroblasts in the lamina propria of adenomas and early CRCs showed higher PDPN expression than did normal mucosae and non-neoplastic lesions (p < 0.01). Pericryptal PDPN expression was a diagnostic feature of adenomas and early CRCs. scRNA-seq of CRCs highlighted that PDPN^high CAFs had distinctly higher COL4A1, COL4A2, and WNT5A expression, unlike well-known CAFs characterized by high FAP, POSTN, or ACTA2 expression. (Conclusions) We demonstrated that pericryptal fibroblasts and reticular cells in the lamina propria are origins of early-stage CRC CAFs and thus have potential as a diagnostic marker for distinguishing colorectal non-neoplastic from neoplastic lesions.

Tregs have the potential to be utilized as a novel therapeutic agent for the treatment of various chronic diseases, including diabetes, Alzheimer's disease, asthma, and rheumatoid arthritis. One of the challenges associated with developing a therapeutic product based on Tregs is the non-selectivity of polyclonal cells. A potential solution to this issue is a generation of antigen-specific CAR-Tregs. Other challenges associated with developing a therapeutic product based on Tregs include the phenotypic instability of these cells in an inflammatory microenvironment, discrepancies between engineered Treg-like cells and natural Tregs, and the expression of dysfunctional isoforms of Treg marker genes. This review presents a summary of proposed strategies for addressing these challenges.

Soluble CD163 (sCD163) is a circulating inflammatory mediator, indicative of acute and chronic, systemic and non-systemic inflammatory conditions. It is the cleavage outcome, consisting of almost the entire extracellular domain, of the CD163, a receptor expressed in monocytic lineages. Its expression is proportional to the abundance of CD163⁺ macrophages. Various mechanisms trigger the shedding of the CD163 receptor or the accumulation of CD163-expressing macrophages, inducing the sCD163 concentration in the circulation and bodily fluids. The activities of sCD163 range from hemoglobin (Hb) scavenging, macrophage marker, decoy receptor for cytokines, participation in immune defense mechanisms, and paracrine effects in various tissues, including the endothelium. It is an established marker of macrophage activation and thus participates in many diseases, including chronic inflammatory conditions, such as atherosclerosis, asthma, and rheumatoid arthritis; acute inflammatory conditions, such as sepsis, hepatitis, and malaria; insulin resistance; diabetes; and tumors. The sCD163 levels have been correlated with the severity, stage of the disease, and clinical outcome for many of these conditions. This review article summarizes the expression and role of sCD163 and its precursor protein, CD163, outlines the sCD163 generation mechanisms, the biological activities, and the known underlying molecular mechanisms, with an emphasis on its impact on the endothelium and its contribution in the pathophysiology of human diseases.

Cardiovascular diseases are a leading cause of mortality worldwide, and the risks of both developing a disease and receiving a poor prognosis increase with age. With increasing life expectancy, understanding the mechanisms underlying heart aging has become critical. Traditional techniques have supported research into finding the physiological changes and hallmarks of cardiovascular aging, including oxidative stress, disabled macroautophagy, loss of proteostasis, and epigenetic alterations, among others. The advent of high-throughput multi-omics techniques offers new perspectives on the molecular mechanisms and cellular processes in the heart, guiding the development of therapeutic targets. This review explores the contributions and characteristics of these high-throughput techniques to unraveling heart aging. We discuss how different high-throughput omics approaches, both alone and in combination, produce robust and exciting new findings and outline future directions and prospects in studying heart aging in this new era.

Skin mast cells (MCs) mediate acute allergic reactions in the cutaneous environment and contribute to chronic dermatoses, including urticaria, and atopic or contact dermatitis. The cAMP response element binding protein (CREB), an evolutionarily well conserved transcription factor (TF) with over 4,000 binding sites in the genome, was recently found to form a feedforward loop with KIT, maintaining MC survival. The most selective MC function is degranulation with its acute release of prestored mediators. Herein, we asked whether CREB contributes to the expression and function of the degranulation-competent receptors FcεRI and MRGPRX2. Interference with CREB by pharmacological inhibition (CREBi, 666-15) or RNA interference only slightly affected the expression of these receptors, while KIT was strongly attenuated. Interestingly, MRGPRX2 surface expression moderately increased following CREB-knockdown, whereas MRGPRX2-dependent exocytosis simultaneously decreased. FcεRI expression and function were regulated consistently, although the effect was stronger at the functional level. Preformed MC mediators (tryptase, histamine, β-hexosaminidase) remained comparable following CREB attenuation, suggesting that granule synthesis did not rely on CREB function. Collectively, in contrast to KIT, FcεRI and MRGPRX2 moderately depend on unperturbed CREB function. Nevertheless, CREB is required to maintain MC releasability irrespective of stimulus, insinuating that CREB may operate by safeguarding the degranulation machinery. To our knowledge, CREB is the first factor identified to regulate MRGPRX2 expression and function in opposite direction. Overall, the ancient TF is an indispensable component of skin MCs, orchestrating not only survival and proliferation but also their secretory competence.

The epidermis of the skin and skin appendages, such as nails, hair and sebaceous glands, depend on a balance of cell proliferation and terminal differentiation in order to fulfill their functions at the interface of the body and the environment. The differentiation of epithelial cells of the skin, commonly referred to as keratinocytes, involves major remodeling processes that generate metabolically inactive cell remnants serving as building blocks of the epidermal stratum corneum, nail plates and hair shafts. Only sebaceous gland differentiation results in cell disintegration and holocrine secretion. A series of studies performed in the past decade have revealed that the lysosome-dependent intracellular degradation mechanism of autophagy is active during keratinocyte differentiation, and the blockade of autophagy significantly alters the properties of the differentiation products. Here, we present a model for the autophagy-mediated degradation of organelles and cytosolic proteins as an important contributor to cellular remodeling in keratinocyte differentiation. The roles of autophagy are discussed in comparison to alternative intracellular degradation mechanisms and in the context of programmed cell death as an integral end point of epithelial differentiation.