Journal of Immunology Research最新文献

The current understanding of the avian immune system primarily stems from research conducted in chickens, given their economic significance as a food source. Extending the research to other avian species like Psittaciformes requires the use of label-free techniques. Therefore, budgerigar (Melopsittacus undulatus) splenic leukocytes were characterized in this study, with the help of an immunological toolbox, integrating single-cell transcriptomics and multiplex RNA in situ hybridization (ISH). Twenty-four distinct psittacine splenic leukocyte populations were identified and characterized, including, amongst others, germinal center (GC) B cells and regulatory T cells (Tregs). For each of these 24 populations, markers were defined for subsequent use in immunological assays. To further examine splenic organization, multiplex RNA ISH was applied, successfully characterizing six out of the nine selected markers. This study showed that the psittacine immune system closely mirrors that of chickens. However, a detailed, comprehensive examination was hindered by the lack of a complete sequenced and annotated budgerigar genome and the limited number of replicates. Consequently, further investigation is imperative to advance our understanding of the avian immune system.

Introduction: The progressive immunological impairment associated with human immunodeficiency virus (HIV) infection is partially mediated by the programmed cell death protein-1 (PD-1)/programed death-ligand 1(PD-L1) inhibitory pathway. This investigation aims to evaluate the influence of PD-1 on immune reconstitution in patients undergoing antiretroviral therapy (ART), with data visualized through principal component analysis (PCA).

Materials and methods: Data from 52 ART-treated individuals achieving viral suppression were analyzed over 12 months. CD4+, CD8+, CD19+, and PD-1/PD-L1 expressions were quantified via flow cytometry at baseline and after 12 months, and immune recovery was assessed at CD4+ thresholds of 500 and 800/μL and CD4+/CD8+ ratios of >0.8 and >1.0 using linear and logistic regression. PCA was applied to visualize clustering of immune recovery patterns based on PD-1/PD-L1 expression levels and immune cell counts, with statistical significance evaluated using ANOVA.

Results: The analyzed group of 52 patients was predominantly male (65.4%; n = 34). PD-1/PD-L1 expression showed modest associations with immune recovery. Higher PD-L1 expression on CD3+ T-cells at baseline was associated with a reduced likelihood of recovery to CD4+>500/μL (OR: 0.79; 95%CI: 0.62-0.99; p = 0.04). Linear regression demonstrated that increased PD-L1 on CD4+ T-cells and PD-1 on CD19+ B-cells positively correlated with higher CD4+/CD8+ ratios at follow-up (coefficient: 0.035 and 0.03, respectively; p < 0.02), while logistic regression indicated that higher PD-1 on CD3+ T-cells increased the odds of recovery to CD4+>500/μL (OR: 1.03; 95% CI: 1.0036-1.07); = 0.03). Notably, this weak signal may result from a general increase in the number of lymphocytes during therapy. PCA did not reveal significant clustering of immune recovery patterns.

Conclusion: PD-1 and PD-L1 expressions on immune cells are weakly associated with immune recovery metrics in individuals undergoing ART. Further research is needed to explore their role in immune reconstitution and potential clinical applications.

Background: Osteoarthritis (OA) is a degenerative joint disease with articular cartilage destruction, triggering a pro-inflammatory response. The aim of this study was to screen key genes associated with fibroblasts based on single-cell transcriptomic data and explore their potential value in OA diagnosis. Methods: We obtained RNA sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq) data of OA from the Gene Expression Omnibus (GEO) database. The CellChat package for cell-to-cell communication analysis and identification of possible ligand-receptor pairs. High-dimensional weighted gene coexpression network analysis (hdWGCNA) was applied to identify the gene modules, and the key genes in the modules were identified and subjected to functional enrichment analysis. Subsequently, limma packages were used to screen for differentially expressed genes (DEGs) between OA and its control samples. Finally, the R package multipleROC was used to test the diagnostic potential of the screened key genes and to construct an OA diagnostic model using the rms package. Result: Eight cell populations were identified and annotated based on scRNA-seq and the percentage of fibroblasts was the highest. The cell-cell communication analysis has suggested that the highest communication probability was seen between mesenchymal cells/T cells and fibroblasts through the pairs of CD99-CD99. The hdWGCNA analysis suggested that genes of modules M3, M4, M5, M6, and M8 (50 genes in total) were highly expressed in fibroblasts. Thereafter, we obtained 394 DEGs in OA and its control samples and took intersections with 50 modular genes and identified seven central genes (including apolipoprotein D [APOD], biglycan [BGN], MXRA5, THY1, C1QTNF3, dermatopontin [DPT], and osteoglycin [OGN]). The constructed diagnostic models showed good predictive performance with all area under the curve (AUC) values >0.8. Finally, a satisfactory diagnostic model was established using these seven genes, and the differences in mRNA expression levels of these genes in OA and normal tissues were verified. Conclusion: For the first time, our study systematically screened and validated key genes with diagnostic potential based on fibroblast-specific single-cell data in combination with hdWGCNA, providing a new theoretical basis and research direction for molecular typing and diagnosis of OA.

Neutrophil extracellular traps (NETs) consist of decondensed chromatin and antimicrobial proteins, which are released from neutrophils and have been implicated in several inflammatory diseases. NETs and interleukin (IL)-17 constitute a feed-forward loop that promotes immunopathological development of inflammation. Therefore, this study aimed to investigate the dynamic distribution of NETs and their colocalization with IL-17 during the progression of apical periodontitis in established mouse models. Apical periodontitis was induced in mice by exposing the pulp of the mandibular first molars, with mandibles harvested on day 0, 7, 14, 21, and 28 after pulp exposure. Micro-CT and high-resolution X-ray scanning showed progressive increases in both the area and volume of periapical lesions from day 0 to day 28. Osteoclasts in the periapical lesions were identified using tartrate-resistant acid phosphatase (TRAP) staining, with their numbers peaking on day 21. Immunofluorescence staining was performed for citrullinated histone H3 (CitH3), myeloperoxidase (MPO), neutrophil elastase (NE), and IL-17 to localize NETs and their colocalization with IL-17 in lesions. NETs, which were visible on day 7 and increased gradually until day 21, primarily located in inflammatory infiltration areas of the periapical tissue. Additionally, western blot analysis showed increased CitH3 expression in periapical lesions on day 21 after pulp exposure, further confirming the presence of NETs. Both RT-qPCR and enzyme-linked immunosorbent assay (ELISA) revealed increased IL-17 expression in periapical lesions. The colocalization of CitH3, the major component of NETs and IL-17 peaked on day 21 after pulp exposure. Furthermore, in vitro experiments demonstrated that IL-17 promoted NETs formation under lipopolysaccharide (LPS)-simulated inflammatory conditions. Our findings indicated that NETs expression changed dynamically and suggested a feedback loop between NETs and IL-17 during the development of apical periodontitis in mouse models.

As a dietary supplement for humans and animals, Astaxanthin (Ax) is widely believed to possess antioxidant and anti-inflammatory properties. In this study, we attempted to evaluate the protective effects of Ax on dextran sodium sulfate (DSS)-induced colitis in mice and the underlying molecular mechanism. Our results suggested that Ax significantly reduced the severity of DSS-induced colitis in mice, as evidenced by increased colon length, decreased disease activity index (DAI), and attenuated inflammatory factors. In addition, Ax significantly increased the diversity of gut microbiota in mice with colitis, remodeled the microbial composition, promoted the production of beneficial bacteria (e.g., Lactobacillaceae), and inhibited the production of harmful bacteria (e.g., Lachnospiraceae and Muribaculaceae). In conclusion, Ax alleviated DSS-induced colitis by maintaining the intestinal barrier and regulating intestinal microbes.

[This corrects the article DOI: 10.1155/2022/1642896.].

In vivo targeting of dendritic cells (DCs) with nanocarriers containing tolerogenic adjuvants is an attractive strategy to dampen inflammation. Here, we used ex vivo skin vaccination to examine the effect of intradermal injection of liposomes loaded with the tolerogenic adjuvants all-trans retinoic acid (RA) and vitamin D3 (VD3). We investigated the effect of intradermal liposome injection on skin DCs and the skin DC-induced T cell response. Our study shows that intradermal injection of RA or VD3-loaded anionic phospholipid 1,2-distearoyl-sn-glycero-3-phosphoglycerol (DSPG) liposomes selectively induces CD14+ dermal DC (DDC) migration while reducing migration of CD1a dim DDCs. Migrated CD14+ DDCs displayed a partially immature phenotype. RA or VD3 liposome-treated CD1a dim DDCs exhibited reduced expression of maturation markers and induced expression of coinhibitory immunoglobulin-like transcript 3 (ILT3). VD3 liposome-treated CD14+ DDCs, as well as, CD1a dim DDCs, exhibited reduced expression of maturation markers, induction of coinhibitory molecules ILT3, and programmed death-ligand 1 (PD-L1). Migrated DCs from RA or VD3 liposome-injected skin differentiated naïve CD4+ T cells into FoxP3+ CD127 low and ICOS+ Tregs, expressing functional regulatory markers. Thus, our findings provide further substantiation for in vivo DC-modulating vaccines with tolerogenic liposomes as a putative clinical therapy for autoimmune diseases and allergies.

[This corrects the article DOI: 10.1155/2024/5537948.].

Background: Macrophages play a critical role in carotid plaque. Understanding the mechanisms of carotid plaque formation based on macrophage heterogeneity could provide valuable insights for clinical intervention. Methods: Single-cell transcriptome and bulk RNA-seq data of carotid plaque were obtained from public databases. Weighted gene correlation network analysis (WGCNA) identified gene modules linked to unstable plaques. Macrophage marker genes were intersected with module genes of WGCNA, followed by using randomForest and LASSO regression to pinpoint key genes. Quantitative real-time PCR (qRT-PCR) and Western blot were used to verify the regulation of key genes at the cellular level. The correlation between the key genes and inflammatory phenotypes was examined by single-sample gene set enrichment analysis (ssGSEA). Results: Single-cell clustering revealed major cellular subpopulations, with elevated macrophage infiltration in carotid plaque. Six key macrophage-associated genes (ADPGK, ATP6V1F, CX3CR1, MYO9B, RNF135, and SLC7A8) were discovered. The qRT-PCR results demonstrated upregulation of ADPGK, ATP6V1F, and RNF135 genes in vascular smooth muscle cells (VSMCs) treated with oxidized low-density lipoprotein (ox-LDL), except for CX3CR1, which was downregulated. Protein expression results showed that expressions of ADPGK, ATP6V1F, RNF135, and SLC7A8 were significantly elevated in the ox-LDL-VSMC group. In addition, most of the immune cells showed significant differences between the unstable arterial plaque group and the control group. Conclusion: This study discovered potential biomarkers that affected carotid plaque progression and macrophage regulation at the single-cell level, and examined their regulatory roles in immune regulation, programed cell death (PCD), and inflammatory factor modulation.

The formation of B cell immunological memory happens after the first encounter with a pathogen. At the germinal center (GC), B cells experience complex transcriptional and epigenetic transitions to differentiate into memory B cells (MBCs) and plasma cells (PCs). In particular, the differentiation of GC B cells into MBCs has been poorly understood, and no clear conclusions on the signals and transcription factors leading to this cell fate have been identified. Recent discoveries in epigenetics and immune memory have elucidated the essential role of epigenetic regulators in establishing the memory B cell (MBC) fate. DNA methylation regulators, histone modifiers, noncoding RNAs (ncRNAs), and chromatin remodelers orchestrate a dynamic reprograming of the MBC phenotype. Positive and negative epigenetic regulators of the B cell program collaborate at each differentiation stage and allow for complex chromatin topology rearrangements and dynamic exposure to transcription and translation. Following MBC fate determination at the GC, the acquired epigenetic modifications induce a poised regulatory state where genes are epigenetically marked to remain transcriptionally inactive, but primed for rapid activation upon stimuli. Thus, a poised epigenetic control over gene expression governs MBC formation and a novel model of epigenetic reprograming is proposed. This model provides a novel perspective on how the B cell fate is determined in the GC and memory is formed, offering insights for improved vaccination and therapeutical approaches.