Identification of two migratory colon ILC2 populations differentially expressing IL-17A and IL-5/IL-13

The kynurenine pathway regulated by intestinal innate lymphoid cells mediates postoperative cognitive dysfunction

Postoperative cognitive dysfunction (POCD) is a prevalent neurological complication that can impair learning and memory for days, months, or even years after anesthesia/surgery. POCD is strongly associated with an altered composition of the gut microbiota (dysbiosis), but the accompanying metabolic changes and their role in gut-brain communication and POCD pathogenesis remain unclear. Here, the present study reports that anesthesia/surgery in aged mice induces elevated intestinal indoleamine 2,3-dioxygenase (IDO) expression and activity, which shifts intestinal tryptophan (TRP) metabolism toward more IDO-catalyzed kynurenine (KYN) and less gut bacteria-catabolized indoleacetic acid (IAA). Both anesthesia/surgery and intraperitoneal KYN administration induce increased KYN levels that correlate with impaired spatial learning and memory, whereas dietary IAA supplementation attenuates the anesthesia/surgery-induced cognitive impairment. Mechanistically, anesthesia/surgery increases interferon-γ (IFN-γ)-producing group 1 innate lymphoid cells (ILC1) in the small intestine lamina propria and elevates intestinal IDO expression and activity, as indicated by the higher ratio of KYN to TRP. The IDO inhibitor 1-MT and antibodies targeting IFN-γ or ILCs mitigate anesthesia/surgery-induced cognitive dysfunction, suggesting that intestinal ILC1 expansion and the ensuing IFN-γ-induced IDO upregulation may be the primary pathway mediating the shift to the KYN pathway in POCD. The ILC1-KYN pathway in the intestine could be a promising therapeutic target for POCD.

CD27 as a Diagnostic Biomarker and Its Role in Immune Heterogeneity and Predicting Clinical Drug Responses in Hashimoto's Thyroiditis

Objective

To identify key genes and potential molecular mechanisms associated with Hashimoto's thyroiditis (HT) to provide new insights for the development of diagnostic and therapeutic targets for this disease.

Methods

Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were conducted to identify the differentially expressed genes (DEGs) associated with HT. A protein-protein interaction (PPI) network was used to obtain hub genes, with CD27 emerging as the key gene in HT. Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, Gene Set Enrichment Analysis (GSEA), and HT-infiltrating immune cell components as well as functions were performed to further investigate the role and potential mechanism of CD27 in cohorts with high and low expression of CD27.

Results

CD27 was found to be upregulated in HT tissues and showed considerable clinical utility in HT. The CD27 of the high-expression cohort exhibited a higher enrichment in immune-related biological processes than the low-expression group. Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) analysis revealed that several activated HT-infiltrating immune cells were strongly associated with CD27, suggesting that CD27 has the potential to be a marker for the immune state in HT.

Conclusion

In our study, CD27 was found to contribute to predicting clinical outcomes in patients with HT, including disease status and response to immunotherapy. CD27 is a promising biomarker for HT microenvironment remodeling, offering insights into new therapeutic approaches to improve treatment of HT.

Pim1 inactivating induces RUNX3 upregulation that improves/alleviates airway inflammation and mucus hypersecretion in vitro and in vivo

PURPOSE

Our research aimed to evaluate whether proto-oncogene serine/threonine-protein kinase Pim-1 (Pim1) inactivation could attenuate asthma by promoting runt-related transcription factor 3 (Runx3) expression and explore the underlying molecular mechanism.

METHOD

Phorbol 12-myristate 13-acetate (PMA, 50 nM) was used to induce inflammation in BEAS-2B human airway epithelial cells. ELISA and immunofluorescence double staining confirmed inflammation modelling and differential expression of Pim1 and Runx3. Pim1 inhibitor (SGI-1776) and Runx3 siRNA (siRunx3) were used in this study. Apoptosis, inflammation, MUC5AC protein expression, Pim1 kinase and Runx3 protein expression, and PI3K/AKT/nuclear factor-κB (NF-κB) pathway-associated protein expression were also assessed by flow cytometry, immunofluorescence and western blot. The effects of Pim1 inactivation on airway inflammation, pathological injury and mucus secretion in wild-type and Runx3 knockout mice were observed by in vivo experiments.

RESULTS

The results of the in vitro experiments showed that PMA stimulation causes BEAS-2B cell apoptosis and promotes the MUC5AC expression. In addition, PMA stimulation activated the PI3K/AKT/NF-κB pathway. SGI-1776 treatment partially reversed these effects, whereas siRunx3 attenuated the effects of SGI-1776 on PMA-stimulated BEAS-2B cells. In vivo experiments showed that in Runx3-KO asthmatic mice, inhibition of Pim1 kinase had less effect on airway inflammation, pathological injury and mucus secretion. Meanwhile, Pim1 kinase expression was higher in Runx3-KO asthmatic mice than in wild-type asthmatic mice. Furthermore, inhibition of Pim1 kinase inhibited activation of the PI3K/AKT/NF-κB pathway, whereas these effects were attenuated in Runx3-KO mice.

CONCLUSION

Our results suggest that Pim1 inactivation can ameliorate airway inflammation and mucus hypersecretion through upregulation of Runx3 and the effect could be mediated through modulation of the PI3K/AKT/NF-κB pathway.

The crosstalk between enteric nervous system and immune system in intestinal development, homeostasis and diseases

The gut is the largest digestive and absorptive organ, which is essential for induction of mucosal and systemic immune responses, and maintenance of metabolic-immune homeostasis. The intestinal components contain the epithelium, stromal cells, immune cells, and enteric nervous system (ENS), as well as the outers, such as gut microbiota, metabolites, and nutrients. The dyshomeostasis of intestinal microenvironment induces abnormal intestinal development and functions, even colon diseases including dysplasia, inflammation and tumor. Several recent studies have identified that ENS plays a crucial role in maintaining the immune homeostasis of gastrointestinal (GI) microenvironment. The crosstalk between ENS and immune cells, mainly macrophages, T cells, and innate lymphoid cells (ILCs), has been found to exert important regulatory roles in intestinal tissue programming, homeostasis, function, and inflammation. In this review, we mainly summarize the critical roles of the interactions between ENS and immune cells in intestinal homeostasis during intestinal development and diseases progression, to provide theoretical bases and ideas for the exploration of immunotherapy for gastrointestinal diseases with the ENS as potential novel targets.

Control of the Development, Distribution, and Function of Innate-Like Lymphocytes and Innate Lymphoid Cells by the Tissue Microenvironment

Recently, considerable attention has been directed toward innate-like T cells (ITCs) and innate lymphoid cells (ILCs) owing to their indispensable contributions to immune responses, tissue homeostasis, and inflammation. Innate-like T cells include NKT cells, MAIT cells, and γδ T cells, whereas ILCs include NK cells, type 1 ILCs (ILC1s), type 2 ILCs (ILC2s), and type 3 ILCs (ILC3s). Many of these ITCs and ILCs are distributed to specific tissues and remain tissue-resident, while others, such as NK cells and some γδ T cells, circulate through the bloodstream. Nevertheless, recent research has shed light on novel subsets of innate immune cells that exhibit characteristics intermediate between tissue-resident and circulating states under normal and pathological conditions. The local microenvironment frequently influences the development, distribution, and function of these innate immune cells. This review aims to consolidate the current knowledge on the functional heterogeneity of ITCs and ILCs, shaped by local environmental cues, with particular emphasis on IL-15, which governs the activities of the innate immune cells involved in type 1 immune responses.

Tissue specific imprinting on innate lymphoid cells during homeostasis and disease process revealed by integrative inference of single-cell transcriptomics

Introduction

Innate lymphoid cells (ILCs) are key components of the immune system, yet the similarity and distinction of the properties across tissues under homeostasis, inflammation and tumor process remain elusive.

Methods

Here we performed integrative inference of ILCs to reveal their transcriptional profiles and heterogeneity from single-cell genomics. We collected a large number of ILCs from human six different tissues which can represent unique immune niches (circulation, lymphoid tissue, normal and inflamed mucosa, tumor microenvironment), to systematically address the transcriptional imprinting.

Results

ILCs are profoundly imprinted by their organ of residence, and tissue-specific distinctions are apparent under pathological conditions. In the hepatocellular carcinoma microenvironment, we identified intermediate c-kit⁺ ILC2 population, and lin^-CD127^- NK-like cells that expressed markers of cytotoxicity including CCL5 and IFNG. Additionally, CD127⁺CD94⁺ ILC1s were preferentially enriched in inflamed ileum from patients with Crohn's disease.

Discussion

These analyses depicted a comprehensive characterization of ILC anatomical distribution and subset heterogeneity, and provided a base line for future temporal or spatial studies focused on tissue-specific ILC-mediated immunity.