-
GeroScience Jun 2024Neuroinflammation, triggered by aberrantly activated microglia, is widely recognized as a key contributor to the initiation and progression of Alzheimer's disease (AD)....
Neuroinflammation, triggered by aberrantly activated microglia, is widely recognized as a key contributor to the initiation and progression of Alzheimer's disease (AD). Microglial activation in the central nervous system (CNS) can be classified into two distinct phenotypes: the pro-inflammatory M1 phenotype and the anti-inflammatory M2 phenotype. In this study, we investigated the effects of a non-invasive rotating magnetic field (RMF) (0.2T, 4Hz) on cognitive and memory impairments in a sporadic AD model of female Kunming mice induced by AlCl and D-gal. Our findings revealed significant improvements in cognitive and memory impairments following RMF treatment. Furthermore, RMF treatment led to reduced amyloid-beta (Aβ) deposition, mitigated damage to hippocampal morphology, prevented synaptic and neuronal loss, and alleviated cell apoptosis in the hippocampus and cortex of AD mice. Notably, RMF treatment ameliorated neuroinflammation, facilitated the transition of microglial polarization from M1 to M2, and inhibited the NF-кB/MAPK pathway. Additionally, RMF treatment resulted in reduced aluminum deposition in the brains of AD mice. In cellular experiments, RMF promoted the M1-M2 polarization transition and enhanced amyloid phagocytosis in cultured BV2 cells while inhibiting the TLR4/NF-кB/MAPK pathway. Collectively, these results demonstrate that RMF improves memory and cognitive impairments in a sporadic AD model, potentially by promoting the M1 to M2 transition of microglial polarization through inhibition of the NF-кB/MAPK signaling pathway. These findings suggest the promising therapeutic applications of RMF in the clinical treatment of AD.
PubMed: 38904930
DOI: 10.1007/s11357-024-01223-y -
Lab on a Chip Jun 2024Droplets generated through microfluidics serve as a common platform for assembling artificial cells, which are feasibly tailored using microfluidic methodology. The...
Droplets generated through microfluidics serve as a common platform for assembling artificial cells, which are feasibly tailored using microfluidic methodology. The ability of natural cells to undergo shape changes, such as phagocytosis, is a typical characteristic that researchers aim to mimic in artificial cells. However, simulating the deformation behavior of natural cells within droplets is exceptionally challenging. Here, this study reports a pinocytosis-like phenomenon observed in droplets, termed "droplet drinking". When droplets traverse a capillary with constrictions, the shear force from the continuous-phase fluid induces relative motion within the droplets, creating concave regions at the rear. These regions facilitate engulfing of the continuous-phase fluid, resulting in the formation of multiple emulsions. This behavior is influenced by the capillary number, and the size of the ingested droplets is governed by the interfacial tension between the two phases. The production of multicore or multi-shell emulsions can be easily accomplished by making slight adjustments to the constrictions. Furthermore, this method demonstrates the integration of reactants into pre-existing droplets, facilitating biochemical reactions. This study presents a convenient approach for generating complex emulsions and an innovative strategy for studying deformation behavior in droplet-based artificial cells.
PubMed: 38904151
DOI: 10.1039/d4lc00381k -
MedComm Jul 2024Type 2 diabetes mellitus (T2DM) and periodontitis (PD) have intricated connections as chronic inflammatory diseases. While the immune response is a key factor that...
Type 2 diabetes mellitus (T2DM) and periodontitis (PD) have intricated connections as chronic inflammatory diseases. While the immune response is a key factor that accounts for their association, the underlying mechanisms remain unclear. To gain a deeper understanding of the connection, we conducted research using a multiomics approach. We generated whole genome and methylation profiling array data from the periodontium of PD patients with DM (PDDM) and without DM to confirm genetic and epigenetic changes. Independent bulk and single-cell RNA sequencing data were employed to verify the expression levels of hypo-methylated genes. We observed a gradual rise in C>T base substitutions and hypomethylation in PD and PDDM patients compared with healthy participants. Furthermore, specific genetic and epigenetic alterations were prominently associated with the Fc-gamma receptor-mediated phagocytosis pathway. The upregulation of these genes was confirmed in both the periodontal tissues of PD patients and the pancreatic tissues of T2DM patients. Through single-cell RNA analysis of peripheral blood mononuclear cells, substantial upregulation of Fc-gamma receptors and related genes was particularly identified in monocytes. Our findings suggest that targeting the Fc-gamma signaling pathway in monocytes holds promise as a potential treatment strategy for managing systemic complications associated with diabetes.
PubMed: 38903536
DOI: 10.1002/mco2.620 -
Frontiers in Immunology 2024Protein kinases are indispensable reversible molecular switches that adapt and control protein functions during cellular processes requiring rapid responses to internal...
INTRODUCTION
Protein kinases are indispensable reversible molecular switches that adapt and control protein functions during cellular processes requiring rapid responses to internal and external events. Bacterial infections can affect kinase-mediated phosphorylation events, with consequences for both innate and adaptive immunity, through regulation of antigen presentation, pathogen recognition, cell invasiveness and phagocytosis. (), a human respiratory tract pathogen and a major cause of community-acquired pneumoniae, affects phosphorylation-based signalling of several kinases, but the pneumococcal mediator(s) involved in this process remain elusive. In this study, we investigated the influence of pneumococcal HO on the protein kinase activity of the human lung epithelial H441 cell line, a generally accepted model of alveolar epithelial cells.
METHODS
We performed kinome analysis using PamGene microarray chips and protein analysis in Western blotting in H441 lung cells infected with wild type () or with -a deletion mutant strongly attenuated in HO production- to assess the impact of pneumococcal hydrogen peroxide (HO) on global protein kinase activity profiles.
RESULTS
Our kinome analysis provides direct evidence that kinase activity profiles in infected H441 cells significantly vary according to the levels of pneumococcal HO. A large number of kinases in H441 cells infected with are significantly downregulated, whereas this no longer occurs in cells infected with the mutant strain, which lacks HO In particular, we describe for the first time HO-mediated downregulation of Protein kinase B (Akt1) and activation of lymphocyte-specific tyrosine protein kinase (Lck) via HO-mediated phosphorylation.
Topics: Streptococcus pneumoniae; Hydrogen Peroxide; Humans; Phosphorylation; Host-Pathogen Interactions; Cell Line; Protein Kinases; Pneumococcal Infections; Signal Transduction
PubMed: 38903521
DOI: 10.3389/fimmu.2024.1414195 -
Frontiers in Immunology 2024Human milk oligosaccharides (HMOs) are present in high numbers in milk of lactating women. They are beneficial to gut health and the habitant microbiota, but less is...
Human milk oligosaccharides (HMOs) are present in high numbers in milk of lactating women. They are beneficial to gut health and the habitant microbiota, but less is known about their effect on cells from the immune system. In this study, we investigated the direct effect of three structurally different HMOs on human derived macrophages before challenge with (). The study demonstrates that individual HMO structures potently affect the activation, differentiation and development of monocyte-derived macrophages in response to . 6´-Sialyllactose (6'SL) had the most pronounced effect on the immune response against , as illustrated by altered expression of macrophage surface markers, pointing towards an activated M1-like macrophage-phenotype. Similarly, 6'SL increased production of the pro-inflammatory cytokines TNF-α, IL-6, IL-8, IFN-γ and IL-1β, when exposing cells to 6'SL in combination with compared with alone. Interestingly, macrophages treated with 6'SL exhibited an altered proliferation profile and increased the production of the classic M1 transcription factor NF-κB. The HMOs also enhanced macrophage phagocytosis and uptake of . Importantly, the different HMOs did not notably affect macrophage activation and differentiation without exposure. Together, these findings show that HMOs can potently augment the immune response against , without causing inflammatory activation in the absence of , suggesting that HMOs assist the immune system in targeting important pathogens during early infancy.
Topics: Humans; Milk, Human; Staphylococcus aureus; Macrophages; Oligosaccharides; Macrophage Activation; Cytokines; Phagocytosis; Female; Cell Differentiation; Staphylococcal Infections; Cells, Cultured
PubMed: 38903508
DOI: 10.3389/fimmu.2024.1379042 -
Frontiers in Immunology 2024Extracellular vesicles (EVs), characterized by low immunogenicity, high biocompatibility and targeting specificity along with excellent blood-brain barrier permeability,... (Review)
Review
Extracellular vesicles (EVs), characterized by low immunogenicity, high biocompatibility and targeting specificity along with excellent blood-brain barrier permeability, are increasingly recognized as promising drug delivery vehicles for treating a variety of diseases, such as cancer, inflammation and viral infection. However, recent findings demonstrate that the intracellular delivery efficiency of EVs fall short of expectations due to phagocytic clearance mediated by the host mononuclear phagocyte system through Fcγ receptors, complement receptors as well as non-opsonic phagocytic receptors. In this text, we investigate a range of bacterial virulence proteins that antagonize host phagocytic machinery, aiming to explore their potential in engineering EVs to counteract phagocytosis. Special emphasis is placed on IdeS secreted by and ImpA secreted by , as they not only counteract phagocytosis but also bind to highly upregulated surface biomarkers αβ on cancer cells or cleave the tumor growth and metastasis-promoting factor CD44, respectively. This suggests that bacterial anti-phagocytic proteins, after decorated onto EVs using pre-loading or post-loading strategies, can not only improve EV-based drug delivery efficiency by evading host phagocytosis and thus achieve better therapeutic outcomes but also further enable an innovative synergistic EV-based cancer therapy approach by integrating both phagocytosis antagonism and cancer targeting or deactivation.
Topics: Extracellular Vesicles; Phagocytosis; Humans; Animals; Bacterial Proteins; Neoplasms; Integrin alphaVbeta3; Hyaluronan Receptors; Pseudomonas aeruginosa
PubMed: 38903499
DOI: 10.3389/fimmu.2024.1418061 -
Clinical Endoscopy Jun 2024During endoscopy, white spots (WS) are sometimes observed around benign or malignant colorectal tumors; however, few reports have investigated WS, and their significance...
BACKGROUND/AIMS
During endoscopy, white spots (WS) are sometimes observed around benign or malignant colorectal tumors; however, few reports have investigated WS, and their significance remains unknown. Therefore, we investigated the significance of WS from clinical and pathological viewpoints and evaluated its usefulness in endoscopic diagnosis.
METHODS
Clinical data of patients with lesions diagnosed as epithelial tumors from January 1, 2019, to December 31, 2020, were analyzed (n=3,869). We also performed a clinicopathological analysis of adenomas or carcinomas treated with endoscopic resection (n=759). Subsequently, detailed pathological observations of the WS were performed.
RESULTS
The positivity rates for WS were 9.3% (3,869 lesions including advanced cancer and non-adenoma/carcinoma) and 25% (759 lesions limited to adenoma and early carcinoma). Analysis of 759 lesions showed that the WS-positive lesion group had a higher proportion of cancer cases and larger tumor diameters than the WS-negative group. Multiple logistic analysis revealed the following three statistically significant risk factors for carcinogenesis: positive WS, flat lesions, and tumor diameter ≥5 mm. Pathological analysis revealed that WS were macrophages that phagocytosed fat and mucus and were white primarily because of fat.
CONCLUSIONS
WS are cancer-related findings and can become a new criterion for endoscopic resection in the future.
PubMed: 38902852
DOI: 10.5946/ce.2024.027 -
Developmental and Comparative Immunology Jun 2024Norepinephrine (NE) is involved in regulating cytokine expression and phagocytosis of immune cells in the innate immunity of vertebrates. In the present study, the...
Norepinephrine (NE) is involved in regulating cytokine expression and phagocytosis of immune cells in the innate immunity of vertebrates. In the present study, the modulation mechanism of NE on the biosynthesis of TNFs in oyster granulocytes was explored. The transcripts of CgTNF-1, CgTNF-2 and CgTNF-3 were highly expressed in granulocytes, and they were significantly up-regulated after LPS stimulation, while down-regulated after NE treatment. The phagocytic rate and apoptosis index of oyster granulocytes were also triggered by LPS stimulation and suppressed by NE treatment. The mRNA expressions of CgMAPK14 and CgRelish were significantly induced after NE treatment, and the translocation of CgRelish from cytoplasm to nucleus was observed. The concentration of intracellular Ca in granulocytes was significantly up-regulated upon NE incubation, and this trend reverted after the treatment with DOX (specific antagonist for NE receptor, CgA1AR-1). No obvious significance was observed in intracellular cAMP concentrations in the PBS, NE and NE + DOX groups. Once CgA1AR-1 was blocked by DOX, the mRNA expressions of CgMAPK14 and CgRelish were significantly inhibited, and the translocation of CgRelish from cytoplasm to nucleus was also dramatically suppressed, while the mRNA expression of CgTNF-1 and the apoptosis index increased significantly to the same level with those in LPS group, respectively. These results collectively suggested that NE modulated TNF expression in oyster granulocyte through A1AR-p38 MAPK-Relish signaling pathway.
PubMed: 38901503
DOI: 10.1016/j.dci.2024.105217 -
ACS Infectious Diseases Jun 2024Fungal keratitis (FK) is a severe corneal condition caused by pathogenic fungi and is associated with the virulence of fungi and an excessive tissue inflammatory...
Fungal keratitis (FK) is a severe corneal condition caused by pathogenic fungi and is associated with the virulence of fungi and an excessive tissue inflammatory response. Progranulin (PGRN), functioning as a multifunctional growth factor, exerts a pivotal influence on the regulation of inflammation and autophagy. The aim of our research was to analyze the role of PGRN in () keratitis. We found that PGRN expression was increased in the mouse cornea with keratitis. In our experiments, corneas of mice with FK were treated with 100 ng/mL of PGRN. In vitro, RAW 264.7 cells were treated with 10 ng/mL of PGRN before stimulation. The findings suggested that PGRN effectively alleviated corneal edema and decreased the expression of pro-inflammatory cytokines in mice. In stimulated RAW 264.7 cells, PGRN treatment suppressed the expression of pro-inflammatory cytokines IL-6 and TNF-α but promoted the expression of the anti-inflammatory cytokines IL-10. PGRN treatment significantly upregulated the expression of autophagy-related proteins LC3, Beclin-1, and Atg-7. 3-Methyladenine (3-MA, autophagy inhibitor) reversed the regulation of inflammatory cytokines by PGRN. In addition, our study demonstrated that PGRN also enhanced phagocytosis in RAW 264.7 cells. In summary, PGRN attenuated the inflammatory response of keratitis by increasing autophagy and enhanced the phagocytic activity of RAW 264.7 cells. This showed that PGRN had a protective effect on keratitis.
PubMed: 38900967
DOI: 10.1021/acsinfecdis.4c00236 -
Molecular Neurobiology Jun 2024Microglia, the main resident immune cells in the central nervous system, are implicated in the pathogenesis of various neurological disorders. Much of our knowledge on...
Human Microglia-Like Cells Differentiated from Monocytes with GM-CSF and IL-34 Show Phagocytosis of α-Synuclein Aggregates and C/EBPβ-Dependent Proinflammatory Activation.
Microglia, the main resident immune cells in the central nervous system, are implicated in the pathogenesis of various neurological disorders. Much of our knowledge on microglial biology was obtained using rodent microglial cultures. To understand the role of microglia in human disease, reliable in vitro models of human microglia are necessary. Monocyte-derived microglia-like cells (MDMi) are a promising approach. This study aimed to characterize MDMi cells generated from adult human monocytes using granulocyte-macrophage colony-stimulating factor and interleukin-34. To this end, 49 independent cultures of MDMI were prepared, and various methodological and functional studies were performed. We show that with this protocol, adult human monocytes develop into microglia-like cells, a coating is unnecessary, and high cell density seeding is preferable. When compared to monocytes, MDMi upregulate the expression of many, but not all, microglial markers, indicating that, although these cells display a microglia-like phenotype, they cannot be considered bona fide human microglia. At the functional level, MDMi phagocytose α-synuclein aggregates and responds to lipopolysaccharide (LPS) by nuclear translocation of the transcription factor nuclear factor-kappaB (NFkappaB) and the upregulation of proinflammatory genes. Finally, a long-lasting silencing of the transcription factor CCAAT/enhancer protein β (C/EBPβ) was achieved by small interfering RNA, resulting in the subsequent downregulation of proinflammatory genes. This supports the hypothesis that C/EBPβ plays a key role in proinflammatory gene program activation in human microglia. Altogether, this study sheds new light on the properties of MDMi cells and supports these cells as a promising in vitro model for studying adult human microglia-like cells.
PubMed: 38900366
DOI: 10.1007/s12035-024-04289-z