Cells最新文献

Atrial fibrillation (AF) is the most common sustained heart rhythm disorder. It is estimated that AF affects over 52 million people worldwide, with its prevalence expected to double in the next four decades. AF significantly increases the risk of stroke and heart failure, contributing to 340,000 excess deaths annually. Beyond these life-threatening complications, AF results in limitations in physical, emotional, and social well-being causing significant reductions in quality of life and resulting in 8.4 million disability-adjusted life-years per year, highlighting the wide-ranging impact of AF on public health. Moreover, AF is increasingly recognized for its association with cognitive decline and dementia. AF is a chronic and progressive disease characterized by rapid and erratic electrical activity in the atria, often in association with structural changes in the heart tissue. AF is often initiated by triggered activity, often from ectopic foci in the pulmonary veins. These triggered impulses may initiate AF via: (1) sustained rapid firing with secondary disorganization into fibrillatory waves, or (2) by triggering micro re-entrant circuits around the pulmonary venous-LA junction and within the atrial body. In each instance, AF perpetuation necessitates the presence of a vulnerable atrial substrate, which perpetuates and stabilizes re-entrant circuits through a combination of slowed and heterogeneous conduction, as well as functional conduction abnormalities (e.g., fibrosis disrupting tissue integrity, and abnormalities in the intercalated disks disrupting effective cell-to-cell coupling). The re-entry wavelength, determined by conduction velocity and refractory period, is shortened by slowed conduction, favoring AF maintenance. One major factor contributing to these changes is the disruption of the extracellular matrix (ECM), which is induced by atrial fibrosis. Fibrosis-driven disruption of the ECM, especially in the heart and blood vessels, is commonly caused by conditions such as aging, hypertension, diabetes, smoking, and chronic inflammatory or autoimmune diseases. These factors lead to excessive collagen and protein deposition by activated fibroblasts (i.e., myofibroblasts), resulting in increased tissue stiffness, maladaptive remodeling, and impaired organ function. Fibrosis typically occurs when cardiac fibroblasts are activated to myofibroblasts, resulting in the deposition of excessive collagen and other proteins. This change in ECM interferes with the normal electrical function of the heart by creating irregular, fibrotic regions. AF and atrial fibrosis have a reciprocal relationship: AF promotes fibrosis through fibroblast activation and extracellular matrix buildup, while atrial fibrosis can sustain and perpetuate AF, contributing to higher rates of AF recurrence after treatments such as catheter ablation or cardioversion.

Diabetic nephropathy (DN) is the most common cause of kidney failure worldwide. Mesenchymal stromal cells (MSCs) have demonstrated promise for treating DN by promoting kidney repair and regulating inflammation. Allogeneic (Allo)-MSCs may have similar or superior anti-inflammatory effects to autologous (Auto)-MSCs but also have potential to elicit adverse immune responses due to major histocompatibility complex (MHC) mismatches. To better understand how MSC-delivered allo-antigens influence therapeutic effects of Allo-MSCs compared to Auto-MSCs in DN, lentiviral transduction was used to generate adipose-derived MSCs (ADSCs) from DBA/2J (H-2^d) mice which expressed an allogeneic class I MHC protein (H-2K^b). H-2K^b-ADSCs were injected intravenously into male DBA/2J mice at 11 and 13 weeks after initiation of diabetes, and their effects on renal functional and structural indices were compared at week 15 with those of diabetic DBA/2J recipients of vehicle alone or of empty vector-transduced DBA/2J ADSCs (EV-ADSCs). Both EV-ADSCs and H-2K^b-ADSCs resulted in reduced kidney/total body weight ratio, blood urea nitrogen (BUN), urine albumin creatinine ratio (uACR), mesangial matrix expansion (MME) and renal fibrosis compared to vehicle alone, without influencing glycemia or survival. However, H-2K^b-ADSCs recipients had greater reductions in BUN and uACR, reduced intra-renal myeloid cell infiltration, increased splenic regulatory T cell (Treg) proportions and increased intra-renal Treg infiltration and FOXP3 and IL-10 mRNA. Nonetheless, recipients of H-2K^b-ADSCs also had decreased splenic CD4/CD8 T cell ratios, increased circulating anti-H-2K^b IgG antibodies and histological and biochemical evidence of inflammatory liver injury. These novel findings demonstrated that ADSCs expressing an MHC-I allo-antigen had superior beneficial effects on DN than fully autologous ADSCs. Improved DN severity was associated with immune modulation, including Treg enhancement, but also had potentially detrimental immunological effects in mice with established diabetes. The results highlight the need for further investigation of the immune modulatory effects of Allo-MSCs in diabetes and its organ-specific complications.

Non-alcoholic fatty liver disease (NAFLD) is closely linked to metabolic syndrome and circadian rhythm disruption, yet the mechanisms by which lifestyle interventions restore circadian organization remain incompletely understood. In this study, we employed a stringent 3 h time-restricted feeding (TRF) regimen in a mouse model of high-fat diet (HFD)-induced metabolic dysfunction. TRF markedly improved metabolic outcomes, including lipid accumulation, glucose tolerance, and behavioral and physiological rhythms. Importantly, through transcriptomic profiling using RNA sequencing, we found that TRF induced circadian rhythmicity in previously arrhythmic hepatic genes. This approach revealed that TRF promotes transcriptional synchronization within key metabolic pathways. Genes involved in autophagy, fatty acid metabolism, and protein catabolism exhibited coherent peak expression at defined time windows, suggesting that TRF temporally restructures gene networks to enhance metabolic efficiency. This intra-pathway synchronization likely minimizes energy waste and enables cells to execute specialized functions in a temporally optimized manner. Together, our findings identify temporal reorganization of metabolic pathways as a mechanistic basis for the benefits of TRF, providing new insight into circadian-based strategies for managing metabolic disease.

The endolysosomal system plays a pivotal role in cellular function. Before reaching lysosomes for degradation, the endocytosed cargoes are sorted at various stages of endosomal trafficking for recycling and/or rerouting. The proper execution of these processes depends on tightly regulated ion fluxes across endolysosomal membranes. Recent studies have demonstrated the importance of two-pore channels (TPCs), including TPC1 and TPC2, in endolysosomal trafficking. These channels are expressed in the membranes of distinct populations of endosomes and lysosomes, where they respond to nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P₂] to conduct Ca²⁺ and Na⁺ release from these acidic organelles. Here, we discuss the potential implications of Ca²⁺ and Na⁺ fluxes mediated by TPCs across endolysosomal membranes in the physiological and pathophysiological functions of these organellar channels.

Mesenchymal stem cells (MSCs) are multipotent adult cells that are highly valued for their immunomodulatory potential and intrinsic ability to home to inflamed sites. This study specifically utilized human dental pulp stem cells (hDPSCs), a unique MSC subtype derived from the neural crest, due to their reported superior anti-inflammatory capacity. To rigorously test their efficacy, we employed the AIRmax murine model, which exhibits a genetically determined high-inflammatory phenotype. Acute inflammation was induced by subcutaneous injection of the polyacrylamide suspension Biogel P-100. Two hours post-induction, AIRmax mice were treated intravenously with hDPSCs. Our results demonstrate that hDPSC treatment produced significant anti-inflammatory effects evident at 24 h. The treated group showed a pronounced reduction in leukocyte migration and decreased protein extravasation in the inflammatory exudate. Crucially, hDPSCs also modulated molecular mediators, significantly decreasing the pro-inflammatory cytokine TNF-alpha and reactive oxygen species (ROS) production. Furthermore, while hDPSCs efficiently and rapidly homed to the inflammation site within 2 h, their maximal therapeutic benefits only manifested after 24 h. This suggests that their robust capacity to modulate acute inflammatory responses relies not only on rapid migration but also on a paracrine "hit-and-run" mechanism that suppresses cellular infiltration and oxidative stress over time. This study reinforces the potential of hDPSCs as a powerful, multi-target therapeutic agent for inflammatory conditions, supporting further investigation into their precise mechanisms and clinical application.

Cells are continuously exposed to physiological and environmental stressors that disrupt homeostasis, triggering adaptive mechanisms such as the integrated stress response (ISR). A central feature of ISR is the selective translation of activating transcription factor 4 (ATF4), which orchestrates gene programs essential for metabolic adaptation and survival. Stress-induced acute ATF4 expression occurs in diverse mammalian cell types and is typically protective; however, chronic activation contributes to pathologies including cancer and neurodegeneration. Canonical ISR (c-ISR) is initiated by phosphorylation of eIF2α in response to stressors such as endoplasmic reticulum or mitochondrial dysfunction, hypoxia, nutrient deprivation, and infections. This modification suppresses global protein synthesis while promoting ATF4 translation through upstream open reading frames (uORFs) in its 5'UTR. Recently, an alternative pathway, split ISR (s-ISR), enabling ATF4 translation independently of eIF2α phosphorylation, was identified in mice, suggesting ISR adaptability, though its relevance in humans remains unclear. Under normal conditions, cap-dependent translation predominates, mediated by the eIF4F complex and requiring the activity of eIF2B at its initial steps. During translational stress, eIF2α phosphorylation inhibits eIF2B activity, resulting in the formation of stalled initiation complexes, which can aggregate into stress granules (SGs). SGs sequester mRNAs and translation initiation factors, further repressing global translation, while ATF4 mRNA largely escapes sequestration, enabling selective translation. This partitioning highlights a finely tuned regulatory mechanism balancing ATF4 expression during stress. Recent advances reveal that, beyond cis-regulatory uORFs, trans-acting factors such as translation initiation factors and associated RNA-binding proteins critically influence ATF4 translation. Understanding these mechanisms provides insight into ISR plasticity and its implications for development, aging, and disease.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors primarily involving the adrenal medulla and its associated paraganglia, with heterogeneous clinical behavior and complex molecular drivers. This study aimed to characterize DNA methylation and gene expression patterns in PPGLs to understand the molecular differences between tumor subtypes and malignancy. We performed an integrative analysis of DNA methylation (Illumina EPIC 850K) and gene expression profiles (Affymetrix microarrays) in 24 PPGLs, comparing these with The Cancer Genome Atlas (TCGA) data, to delineate cluster- and malignancy-specific epigenetic patterns. Comparison between pseudohypoxic Cluster I and kinase-signaling Cluster II tumors revealed 13 differentially methylated CpG sites, with a specific CpG within DSCAML1 showing hypermethylation in Cluster II accompanied by increased expression, suggesting context-dependent gene body methylation effects. Benign versus malignant comparisons identified 101 differentially methylated CpGs, including hypermethylated CpG in BAIAP2L1 and hypomethylated CpG in SHANK1 in malignant tumors. Pathway enrichment of differentially methylated genes revealed alterations in Notch signaling, adherens junctions, cytoskeletal regulation, and intracellular transport. Gene expression analysis demonstrated partial overlap between clusters, with malignant tumors exhibiting distinct transcriptional profiles involving RNA processing, metabolism, and adhesion pathways. Correlation between methylation and expression was generally limited, emphasizing that methylation-dependent gene regulation is a locus-specific and context-dependent regulation. These findings illustrate a complex interplay between epigenetic modifications and transcriptional programs in PPGLs, enhancing our understanding of molecular heterogeneity and tumor classification, and identifying candidate biomarkers and therapeutic targets for malignant progression.

The Transient Receptor Potential Ankyrin 1 (TRPA1) channel is a non-selective cation channel activated by a range of physical and chemical stimuli. While primarily studied in neuronal tissues, TRPA1 is also expressed in human keratinocytes, where its role remains poorly understood. Here, we investigated TRPA1 expression and function in keratinocytes and examined the effects of its activation on cellular proliferation, immune activation, and neuropeptide release under both basal and inflammatory stimuli. TRPA1 expression was detected in basal keratinocytes and was upregulated by pro-inflammatory cytokines. Stimulation with the TRPA1 agonist allyl isothiocyanate (AITC) induced a rapid calcium influx, confirming functional channel activity. AITC at 5 µM did not induce cytotoxicity but significantly reduced keratinocyte proliferation and caused cell cycle arrest. Under stimulation with TNF-α and IFN-γ, TRPA1 activation decreased the surface expression of HLA-DR and ICAM-1, and downregulated mRNA levels of CXCL10, CXCL8, CCL5, and CCL20, while IL-6 expression remained unchanged. Furthermore, AITC treatment reduced the secretion of Substance P, but not CGRP. These findings indicate that TRPA1 functions as a cytokine-inducible, immunomodulatory receptor in human keratinocytes, capable of attenuating proliferation and inflammatory activation without compromising cell viability, thereby suggesting a potential role in maintaining skin homeostasis and modulating cutaneous inflammation.

Complete or partial loss of smell (anosmia), sometimes in association with distorted olfactory perceptions (parosmia), is a common neurological symptom affecting nearly 60% of patients suffering from post-acute neurological sequelae of COronaVIrus Disease of 2019 (COVID-19) syndrome, called long COVID. Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) may gain access from the nasal cavity to the brain (neurotropism), and the olfactory route has been proposed as a peripheral site of virus entry. COVID-19 is a risk factor for developing Alzheimer's Disease (AD), an age-dependent and progressive neurodegenerative disorder characterized in affected patients by early olfaction dysfunction that precedes signs of cognitive decline associated with neurodegeneration in vulnerable brain regions of their limbic system. Here, we summarize the recent literature data supporting the causal correlation between the persistent olfactory deterioration following SARS-CoV-2 infection and the long-delayed manifestation of AD-like memory impairment. SARS-CoV-2 infection of the olfactory neuroepithelium is likely to trigger a pattern of detrimental events that, directly and/or indirectly, affect the anatomically interconnected hippocampal and cortical areas, thus resulting in tardive clinical dementia. We also delineate future advancement on pharmacological and rehabilitative treatments to improve the olfactory dysfunction in patients recovering even from the acute/mild phase of COVID-19. Collectively, the present review aims at highlighting the physiopathological nexus between COVID-19 anosmia and post-pandemic mental health to favor the development of best-targeted and more effective therapeutic strategies in the fight against the long-term neurological complications associated with SARS-CoV-2 infection.

Malignant pleural mesothelioma (MPM) is a very aggressive tumor. The prognostic value of PD-L1 and BAP1 expression has been investigated in many studies. A retrospective study was conducted that analyzed PD-L1 and BAP1 expression as prognostic biomarkers in patients with MPM. The study included 53 patients with MPM. PD-L1 expression ≥ 1% was found in 39.6%, and BAP1 loss was found in 81.1% of patients. The median overall survival (mOS) was 11 months. Subtype of MPM (p = 0.045), early tumor stage (p = 0.049), therapy (p = 0.002), and good PS (0-1) (p = 0.012) were associated with better survival. Expression of PD-L1 and BAP1 did not show statistical significance regarding OS, but OS was numerically shorter in patients with PD-L1 ≥ 10% (5 vs. 12 months) and longer in patients with BAP1 loss (12 vs. 4 months). In patients with PD-L1 ≥ 1% and BAP1 loss, the median progression-free survival (mPFS) was numerically longer (10 vs. 7 months) but in patients with PD-L1 ≥ 1% and BAP1 positivity, PFS was statistically significantly shorter (1 vs. 7 months, p = 0.048). Our results did not show that PD-L1 and BAP1 are prognostic biomarkers for MPM, but positive PD-L1 expression and BAP1 loss were associated with worse survival in patients with MPM.