Mass cytometry profiling of human dendritic cells in blood and tissues

Circulating immune cells and apolipoprotein A mediation: a Mendelian randomization study on hypertensive disorder of pregnancy

Background

Studies using observational epidemiology have indicated that inflammation and immunological dysregulation are important contributors to placental and renal failure, which ultimately results in maternal hypertension. The potential causal relationships between the immunophenotypes and hypertensive disorder of pregnancy (HDP) are yet unclear.

Methods

We conducted two-sample Mendelian randomization (MR) analyses to thoroughly examine the relationship between immunophenotypes and HDP. The GWAS data on immunological traits was taken from public catalog for 731 immunophenotypes and the summarized GWAS data in 4 types of HDP were retrieved from FinnGen database. The link between immune cell traits and HDP was examined through our study methodology, taking into account both direct relationships and mediation effects of apolipoprotein A (apoA). The inverse variance weighted (IVW) method served as the main analysis, while sensitivity analysis was carried out as a supplement.

Results

We identified 14 highly correlative immunophenotypes and 104 suggestive possible factors after investigating genetically predicted immunophenotype biomarkers. According to the IVW analysis, there was a strong correlation between HDP and HLA DR on DC and plasmacytoid DC. Reverse MR analysis showed that there was no statistically significant effect of HDP on immune cells in our investigation. Mediation analysis confirmed that apoA mediates the interaction between HLA DR on DC and HDP.

Conclusion

Our results highlight the complex interplay of immunophenotypes, apoA, and HDP. Moreover, the pathophysiological link between HLA DR on DC and HDP was mediated by the level of apoA.

Multiplexed imaging to reveal tissue dendritic cell spatial localisation and function

Dendritic cells (DCs) play a pivotal role in immune surveillance, acting as sentinels that coordinate immune responses within tissues. Although differences in the identity and functional states of DC subpopulations have been identified through multiparametric flow cytometry and single-cell RNA sequencing, these methods do not provide information about the spatial context in which the cells are located. This knowledge is crucial for understanding tissue organisation and cellular cross-talk. Recent developments in multiplex imaging techniques can now offer insights into this complex spatial and functional landscape. This review provides a concise overview of these imaging methodologies, emphasising their application in identifying DCs to delineate their tissue-specific functions and aiding newcomers in navigating this field.

Transitional dendritic cells are distinct from conventional DC2 precursors and mediate proinflammatory antiviral responses

High-dimensional approaches have revealed heterogeneity amongst dendritic cells (DCs), including a population of transitional DCs (tDCs) in mice and humans. However, the origin and relationship of tDCs to other DC subsets has been unclear. Here we show that tDCs are distinct from other well-characterized DCs and conventional DC precursors (pre-cDCs). We demonstrate that tDCs originate from bone marrow progenitors shared with plasmacytoid DCs (pDCs). In the periphery, tDCs contribute to the pool of ESAM+ type 2 DCs (DC2s), and these DC2s have pDC-related developmental features. Different from pre-cDCs, tDCs have less turnover, capture antigen, respond to stimuli and activate antigen-specific naïve T cells, all characteristics of differentiated DCs. Different from pDCs, viral sensing by tDCs results in IL-1β secretion and fatal immune pathology in a murine coronavirus model. Our findings suggest that tDCs are a distinct pDC-related subset with a DC2 differentiation potential and unique proinflammatory function during viral infections.

A universal mass tag based on polystyrene nanoparticles for single-cell multiplexing with mass cytometry

Mass cytometry (MC) is an emerging bioanalytical technique for high-dimensional biomarkers interrogation simultaneously on individual cells. However, the sensitivity and multiplexed analysis ability of MC was highly restricted by the current metal chelating polymer (MCP) mass tags. Herein, a new design strategy for MC mass tags by using a commercial available and low cost classical material, polystyrene nanoparticle (PS-NP) to carry metals was reported. Unlike inorganic materials, sub-micron-grade metal-loaded polystyrene can be easily detected by MC, thus it is not essential to pursue extremely small particle size in this mass tag design strategy. An altered cell staining buffer can significantly lower the nonspecific binding (NSB) of non-functionalized PS-NPs, revealing another method to lower NSB beside surface modification. The metal doped PS-NP_Abs mass tags showed high compatibility with MCP mass tags and 5-fold higher sensitivity. By using Hf doped PS-NP_Abs as mass tags, four new MC detection channels (¹⁷⁷Hf, ¹⁷⁸Hf, ¹⁷⁹Hf and ¹⁸⁰Hf) were developed. In general, this work provides a new strategy in designing MC mass tags and lowering NSB, opening up possibility of introducing more potential MC mass tag candidates.

Gut microbiota: A target for prebiotics and probiotics in the intervention and therapy of food allergy

Food allergy has become a major public health problem all over the world. Evidence showed that allergic reactions induced by food proteins often lead to disturbances in the gut microbiota (symbiotic bacteria). Gut microbiota plays an important role in maintaining the balance between intestinal immune tolerance and allergic reactions. Dietary intervention has gradually become an important method for the prevention and treatment of allergic diseases, and changing the composition of gut microbiota through oral intake of prebiotics and probiotics may serve as a new effective adjuvant treatment measure for allergic diseases. In this paper, the main mechanism of food allergy based on intestinal immunity was described firstly. Then, the clinical and experimental evidence showed that different prebiotics and probiotics affect food allergy by changing the structure and composition of gut microbiota was summarized. Moreover, the molecular mechanism in which the gut microbiota and their metabolites may directly or indirectly regulate the immune system or intestinal epithelial barrier function to affect food immune tolerance of host were also reviewed to help in the development of food allergy prevention and treatment strategies based on prebiotics and probiotics.