Bridging Chronic Inflammation and Digestive Cancer: The Critical Role of Innate Lymphoid Cells in Tumor Microenvironments.

The incidence and mortality of digestive system-related cancers have always been high and attributed to the heterogeneity and complexity of the immune microenvironment of the digestive system. Furthermore, several studies have shown that chronic inflammation in the digestive system is responsible for cancer incidence; therefore, controlling inflammation is a potential strategy to stop the development of cancer. Innate Lymphoid Cells (ILC) represent a heterogeneous group of lymphocytes that exist in contrast to T cells. They function by interacting with cytokines and immune cells in an antigen-independent manner. In the digestive system cancer, from the inflammatory phase to the development, migration, and metastasis of tumors, ILC have been found to interact with the immune microenvironment and either control or promote these processes. The conventional treatments for digestive tumors have limited efficacy, therefore, ILC-associated immunotherapies are promising strategies. This study reviews the characterization of different ILC subpopulations, how they interact with and influence the immune microenvironment as well as chronic inflammation, and their promotional or inhibitory role in four common digestive system tumors, including pancreatic, colorectal, gastric, and hepatocellular cancers. In particular, the review emphasizes the role of ILC in associating chronic inflammation with cancer and the potential for enhanced immunotherapy with cytokine therapy and adoptive immune cell therapy.

New insights into allergic rhinitis treatment: MSC nanovesicles targeting dendritic cells.

Allergic rhinitis (AR) is a condition with limited treatment options. This study investigates the potential use of mesenchymal stem cell (MSC) nanovesicles as a novel therapy for AR. Specifically, the study explores the underlying mechanisms of MSC nanovesicle therapy by targeting dendritic cells (DCs). The researchers fabricated DC-targeted P-D2-EVs nanovesicles and characterized their properties. Transcriptomic sequencing and single-cell sequencing analyses were performed to study the impact of P-D2-EVs on AR mice, identifying core genes involved in the treatment. In vitro cell experiments were conducted to validate the effects of P-D2-EVs on DC metabolism, Th2 differentiation, and ILC2 activation. The results showed that P-D2-EVs efficiently targeted DCs. Transcriptomic sequencing analysis revealed differential expression of 948 genes in nasal tissue DCs of mice treated with P-D2-EVs. Single-cell sequencing further revealed that P-D2-EVs had inhibitory effects on DC activation, Th2 differentiation, and ILC2 activation, with Fut1 identified as the core gene. Validation experiments demonstrated that P-D2-EVs improved IL10 metabolism in DCs by downregulating Fut1 expression, thereby suppressing Th2 differentiation and ILC2 activation. Animal experiments confirmed the inhibitory effects of P-D2-EVs and their ability to ameliorate AR symptoms in mice. The study suggests that P-D2-EVs reshape DC metabolism and suppress Th2 differentiation and ILC2 activation through the inhibition of the Fut1/ICAM1/P38 MAPK signaling pathway, providing a potential therapeutic approach for AR.

Sirtuin 6 inhibits group 3 innate lymphoid cell function and gut immunity by suppressing IL-22 production.

Introduction: Group 3 innate lymphoid cells (ILC3s) are enriched in the intestinal mucosa and play important roles in host defense against infection and inflammatory diseases. Sirtuin 6 (SIRT6) is a nicotinamide adenine dinucleotide (NAD+)- dependent deacetylase and has been shown to control intestinal epithelial cell differentiation and survival. However, the role of SIRT6 in ILC3s remains unknown. Methods: To investigate the role of SIRT6 in gut ILC3s, we generated SIRT6 conditional knockout mice by crossing Rorccre and Sirt6flox/flox mice. Cell number and cytokine production was examined using flow cytometry. Citrobacter rodentium infection and dextran sodium sulfate-induced colitis models were used to determine the role of SIRT6 in gut defense. RT-qPCR, flow cytometry and immunohistochemistry were used to assess the intestinal inflammatory responses. Results: Here we show that SIRT6 inhibits IL-22 expression in intestinal ILC3s in a cell-intrinsic manner. Deletion of SIRT6 in ILC3s does not affect the cell numbers of total ILC3s and subsets, but results in increased IL-22 production. Furthermore, ablation of SIRT6 in ILC3s protects mice against Citrobacter rodentium infection and dextran sodium sulfate-induced colitis. Our results suggest that SIRT6 may play a role in ILC3 function by regulating gut immune responses against bacterial infection and inflammation. Discussion: Our finding provided insight into the relation of epigenetic regulators with IL-22 production and supplied a new perspective for a potential strategy against inflammatory bowel disease.

Single cell sequencing delineates T-cell clonality and pathogenesis of the parapsoriasis disease group.

BACKGROUND: Mycosis fungoides (MF), the most common cutaneous T-cell lymphoma, is often underdiagnosed in early stages due to similarities with benign dermatoses such as atopic dermatitis (AD). Furthermore, the delineation from so-called "parapsoriasis en plaque," a disease that can appear either in a small- or large-plaque form, is still controversial. OBJECTIVE: To characterize the parapsoriasis disease spectrum. METHODS: We performed single-cell RNA sequencing of skin biopsies from patients within the parapsoriasis-to-early-stage MF spectrum, stratified for small and large plaques, and compared them to AD, psoriasis and healthy control skin. RESULTS: 6 out of 8 large-plaque lesions harbored either an expanded alpha/beta or gamma/delta T-cell clone with downregulation of CD7 expression, consistent with a diagnosis of early-stage MF. By contrast, 6 out of 7 small-plaque lesions were polyclonal in nature thereby lacking a lymphomatous phenotype, and also revealed a less inflammatory microenvironment than early-stage MF or AD. Of note, polyclonal small- and large-plaque lesions characteristically harbored a population of NPY+ innate lymphoid cells and displayed a stromal signature of complement upregulation and antimicrobial hyperresponsiveness in fibroblasts and sweat gland cells, respectively. These conditions were clearly distinct from AD or psoriasis, which uniquely harbored CD3+CRTH2+ IL13-expressing "Th2A" cells or strong type 17 inflammation, respectively. CONCLUSION: These data position polyclonal small- and large-plaque dermatitis lesions as a separate disease entity, that characteristically harbors a so far undescribed ILC population. We thus propose the new term "polyclonal parapsoriasis en plaque" to this kind of lesions, as they can be clearly differentiated from early and advanced-stage MF, psoriasis and AD on several cellular and molecular levels.

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.

MicroRNA-142 regulates gut associated lymphoid tissues and group 3 innate lymphoid cells.

The transcriptomic signatures that shape responses of innate lymphoid cells (ILCs) have been well characterised, however post-transcriptional mechanisms which regulate their development and activity remain poorly understood. We demonstrate that ILC groups of the intestinal lamina propria express mature forms of microRNA-142 (miR-142), an evolutionarily conserved microRNA family with several non-redundant regulatory roles within the immune system. Germline Mir142 deletion alters intestinal ILC compositions, resulting in the absence of T-bet+ populations and significant defects in the cellularity and phenotypes of ILC3 subsets including CCR6+ LTi-like ILC3s. These effects were associated with decreased pathology in an innate-immune cell driven model of colitis. Furthermore, Mir142-/- mice demonstrate defective development of gut-associated lymphoid tissues, including a complete absence of mature Peyer's patches. Conditional deletion of Mir142 in ILC3s (RorcΔMir142) supported cell-intrinsic roles for these microRNAs in establishing or maintaining cellularity and functions of LTi-like ILC3s in intestinal associated tissues. RNAseq analysis revealed several target genes and biological pathways potentially regulated by miR-142 microRNAs in these cells. Finally, lack of Mir142 in ILC3 led to elevated IL-17A production. These data broaden our understanding of immune system roles of miR-142 microRNAs, identifying these molecules as critical post-transcriptional regulators of ILC3s and intestinal mucosal immunity.

RIPK3 and caspase-8 interpret cytokine signals to regulate ILC3 survival in the gut.

Group 3 innate lymphoid cells (ILC3s) are abundant in the developing or healthy intestine to critically support tissue homeostasis in response to microbial colonization. However, intestinal ILC3s are reduced during chronic infections, colorectal cancer, or inflammatory bowel disease (IBD), and the mechanisms driving these alterations remain poorly understood. Here we employed RNA sequencing of ILC3s from IBD patients and observed a significant upregulation of RIPK3, the central regulator of necroptosis, during intestinal inflammation. This was modeled in mice where we found that intestinal ILC3s express RIPK3, with conventional (c)ILC3s exhibiting high RIPK3 and low levels of pro-survival genes relative to lymphoid tissue inducer (LTi)-like ILC3s. ILC3-specific RIPK3 is promoted by gut microbiota, further upregulated following enteric infection, and dependent upon IL-23R and STAT3 signaling. However, lineage-specific deletion of RIPK3 revealed a redundant role in ILC3 survival, due to a blockade of RIPK3-mediated necroptosis by caspase 8, which was also activated in response to enteric infection. In contrast, lineage-specific deletion of caspase 8 resulted in loss of cILC3s from the healthy intestine and all ILC3 subsets during enteric infection, which increased pathogen burdens and gut inflammation. This function of caspase 8 required catalytic activity induced by TNF or TL1A and was dispensable if RIPK3 was simultaneously deleted. Caspase 8 activation and cell death were associated with increased Fas on ILC3s, and the Fas-FasL pathway was upregulated by cILC3s during enteric infection, which could restrain the abundance of intestinal ILC3s. Collectively, these data reveal that interpretation of key cytokine signals controls ILC3 survival following microbial challenge, and that an imbalance of these pathways, such as in IBD or across ILC3 subsets, provokes depletion of tissue-protective ILC3s from the inflamed intestine.

Prdm1 positively regulates liver Group 1 ILCs cancer immune surveillance and preserves functional heterogeneity.

Group 1 innate lymphoid cells (ILCs) comprise conventional natural killer (cNK) cells and type 1 innate lymphoid cells (ILC1s). The main functions of liver cNK cells and ILC1s not only include directly killing target cells but also regulating local immune microenvironment of the liver through the secretion of cytokines. Uncovering the intricate mechanisms by which transcriptional factors regulate and influence the functions of liver cNK cells and ILC1s, particularly within the context of liver tumors, presents a significant opportunity to amplify the effectiveness of immunotherapies against liver malignancies. Using Ncr1-drived conditional knockout mouse model, our study reveals the regulatory role of Prdm1 in shaping the composition and maturation of cNK cells. Although Prdm1 did not affect the killing function of cNK cells in an in vivo cytotoxicity model, a significant increase in cancer metastasis was observed in Prdm1 knockout mice. Interferon-gamma (IFN-γ), granzyme B, and perforin secretion decreased significantly in Prdm1-deficient cNK cells and liver ILC1s. Single-cell RNA sequencing (scRNA-seq) data also provided evidences that Prdm1 maintains functional subsets of cNK cells and liver ILC1s and facilitates communications between cNK cells, liver ILC1s, and macrophages. The present study unveiled a novel regulatory mechanism of Prdm1 in cNK cells and liver ILC1s, showing promising potential for developing innovative immune therapy strategies against liver cancer.

Dietary human milk oligosaccharides reduce allergic airway inflammation by modulating SCFAs level and ILC2 activity.

Group 2 innate lymphoid cells (ILC2s) play a crucial role in the progression of asthma, yet the regulatory mechanisms modulating ILC2 responses in asthma remain underexplored. Human milk oligosaccharides (HMOs), vital non-nutritive components of breast milk, are known to significantly shape immune system development and influence the incidence of allergic diseases. However, their impact on ILC2-driven asthma is not fully understood. Our research reveals that dietary HMOs act as potent inhibitors of ILC2 responses and allergic airway inflammation. Treatment with 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL) significantly reduced ILC2-related airway inflammation induced by papain or Alternaria alternata in mice, evidenced by decreased eosinophil (EOS) infiltration and lower IL-5 and IL-13 levels in BALF. Notably, while ILC2 expresses HMO receptors, HMO did not act directly on ILC2 but potentially modulated their activity through alterations in gut microbiota derived SCFAs. HMO treatments alleviated airway inflammation in SCFA-dependent manners, with SCFA depletion or receptor blocking reversing these beneficial effects. This study reveals the potential of dietary HMOs in managing asthma through modulation of ILC2 activity and the gut-lung axis, proposing a new therapeutic avenue that utilises the immunomodulatory capacities of nutritional components to combat respiratory diseases.

Dynamic regulation of innate lymphoid cell development during ontogeny.

The helper-like ILC contains various functional subsets, such as ILC1, ILC2, ILC3 and LTi cells, mediating the immune responses against viruses, parasites, and extracellular bacteria, respectively. Among them, LTi cells are also crucial for the formation of peripheral lymphoid tissues, such as lymph nodes. Our research, along with others', indicates a high proportion of LTi cells in the fetal ILC pool, which significantly decreases after birth. Conversely, the proportion of non-LTi ILCs increases postnatally, corresponding to the need for LTi cells to mediate lymphoid tissue formation during fetal stages and other ILC subsets to combat diverse pathogen infections postnatally. However, the regulatory mechanism for this transition remains unclear. In this study, we observed a preference for fetal ILC progenitors to differentiate into LTi cells, while postnatal bone marrow ILC progenitors preferentially differentiate into non-LTi ILCs. Particularly, this differentiation shift occurs within the first week after birth in mice. Further analysis revealed that adult ILC progenitors exhibit stronger activation of the Notch signaling pathway compared to fetal counterparts, accompanied by elevated Gata3 expression and decreased Rorc expression, leading to a transition from fetal LTi cell-dominant states to adult non-LTi ILC-dominant states. This study suggests that the body can regulate ILC development by modulating the activation level of the Notch signaling pathway, thereby acquiring different ILC subsets to accommodate the varying demands within the body at different developmental stages.

Sensing of Liver-Derived Nicotinamide by Intestinal Group 2 Innate Lymphoid Cells Links Liver Cirrhosis and Ulcerative Colitis Susceptibility.

The correlation between liver disease and the progression of ulcerative colitis (UC) has remained elusive. In this study, it demonstrates that liver injury is intricately linked to the heightened severity of UC in patients, and causes more profound intestinal damage during DSS-induced colitis in mice. Metabolomics analysis of plasma from liver cirrhosis patients shows liver injury compromising nicotinamide supply for NAD+ biosynthesis in the intestine. Subsequent investigation identifies intestinal group 2 innate lymphoid cells (ILC2s) are responsible for liver injury-exacerbated colitis. Reconstitution of ILC2s or the restoration of NAD+ metabolism proves effective in relieving liver injury-aggravated experimental colitis. Mechanistically, the NAD+ salvage pathway regulates gut ILC2s in a cell-intrinsic manner by supporting the generation of succinate, which fuels the electron transport chain to sustaining ILC2s function. This research deepens the understanding of cellular and molecular mechanisms in liver disease-UC interplay, identifying a metabolic target for innovative treatments in liver injury-complicated colitis.

Expansion and Maturation of Innate Lymphoid Cell Precursors Using Human iPSC-Derived Intestinal Organoids.

Innate lymphoid cells (ILC) are enriched at mucosal barrier sites where they play critical roles in development and disease. Mucosal organoids offer a robust platform for the simultaneous differentiation and expansion of all subsets of mature ILC from a shared peripheral blood precursor. Critically, organoid identity drives tissue-specific imprinting of the culture-derived mature innate lymphoid cells, allowing for the study of bidirectional interactions between, e.g., intestinal organoids and intestine-specific ratios and populations of ILC. This protocol reduces the need for feeder cell lines and complex cytokine cocktails used to mature and maintain ILC, instead relying on a native niche of protein signals provided by mucosal epithelial cells. This protocol details the generation of human intestinal organoids (HIO) from human-induced pluripotent stem cells (hiPSC), and the subsequent establishment of co-cultures between HIO and ILC precursors for expansion and maturation. This approach has extensive applications for mechanistic studies of fundamental biological processes and as a potential GMP-compatible source of ILC for future cell therapies.

Exploring the role of innate lymphoid cells in the periodontium: insights into immunological dynamics during orthodontic tooth movement.

Background: The periodontal ligament (PDL) experiences considerable mechanical stresses between teeth and bone, vital for tissue adaptation, especially in orthodontic tooth movement (OTM). While recent research emphasizes the role of innate lymphoid cells (ILCs) in regulating sterile inflammation, their involvement in periodontal tissues during OTM remains largely unexplored. Methods: In this study, PDL tissues from orthodontic patients (n = 8) were examined using flow cytometry to detect ILC subtypes. Transwell co-culture systems were used to expose PDL cells to mechanical strain, followed by measuring migration and ratios of sorted ILC subtypes. Statistical analyses were conducted using paired Student's t-test, Kruskal-Wallis test, Dunn's post-test and one-way/two-way ANOVA with Tukey's post-test (p≤ 0.05; **, p≤ 0.01; ***, p≤ 0.001). Results: Our findings demonstrate a significant increase in CD127+ CD161+ ILC frequencies in PDL tissues during OTM, indicating ILC involvement in sterile inflammation induced by orthodontic forces. Co-culture assays show directed migration of ILC subsets towards PDL cells and substantial proliferation and expansion of ILCs. Conclusions: This study is the first to comprehensively investigate the role of ILCs in sterile inflammation during OTM, revealing their presence and distribution within PDL tissues' innate immune response in vivo, and exploring their migratory and proliferative behavior in vitro. The results suggest a crosstalk between ILCs and PDL cells, potentially influencing the inflammatory response and tissue remodeling processes associated with OTM.

Paeoniflorin ameliorates chronic colitis via the DR3 signaling pathway in group 3 innate lymphoid cells.

Inhibiting the death receptor 3 (DR3) signaling pathway in group 3 innate lymphoid cells (ILC3s) presents a promising approach for promoting mucosal repair in individuals with ulcerative colitis (UC). Paeoniflorin, a prominent component of Paeonia lactiflora Pall., has demonstrated the ability to restore barrier function in UC mice, but the precise mechanism remains unclear. In this study, we aimed to delve into whether paeoniflorin may promote intestinal mucosal repair in chronic colitis by inhibiting DR3 signaling in ILC3s. C57BL/6 mice were subjected to random allocation into 7 distinct groups, namely the control group, the 2 % dextran sodium sulfate (DSS) group, the paeoniflorin groups (25, 50, and 100 mg/kg), the anti-tumor necrosis factor-like ligand 1A (anti-TL1A) antibody group, and the IgG group. We detected the expression of DR3 signaling pathway proteins and the proportion of ILC3s in the mouse colon using Western blot and flow cytometry, respectively. Meanwhile, DR3-overexpressing MNK-3 cells and 2 % DSS-induced Rag1-/- mice were used for verification. The results showed that paeoniflorin alleviated DSS-induced chronic colitis and repaired the intestinal mucosal barrier. Simultaneously, paeoniflorin inhibited the DR3 signaling pathway in ILC3s and regulated the content of cytokines (Interleukin-17A, Granulocyte-macrophage colony stimulating factor, and Interleukin-22). Alternatively, paeoniflorin directly inhibited the DR3 signaling pathway in ILC3s to repair mucosal damage independently of the adaptive immune system. We additionally confirmed that paeoniflorin-conditioned medium (CM) restored the expression of tight junctions in Caco-2 cells via coculture. In conclusion, paeoniflorin ameliorates chronic colitis by enhancing the intestinal barrier in an ILC3-dependent manner, and its mechanism is associated with the inhibition of the DR3 signaling pathway.

LGG promotes activation of intestinal ILC3 through TLR2 receptor and inhibits salmonella typhimurium infection in mice.

Salmonella is a foodborne pathogen that causes disruption of intestinal mucosal immunity, leading to acute gastroenteritis in the host. In this study, we found that Salmonella Typhimurium (STM) infection of the intestinal tract of mice led to a significant increase in the proportion of Lacticaseibacillus, while the secretion of IL-22 from type 3 innate lymphoid cells (ILC3) increased significantly. Feeding Lacticaseibacillus rhamnosus GG (LGG) effectively alleviated the infection of STM in the mouse intestines. TLR2-/- mice experiments found that TLR2-expressing dendritic cells (DCs) are crucial for LGG's activation of ILC3. Subsequent in vitro experiments showed that heat-killed LGG (HK-LGG) could promote DCs to secrete IL-23, which in turn further promotes the activation of ILC3 and the secretion of IL-22. Finally, organoid experiments further verified that IL-22 secreted by ILC3 can enhance the intestinal mucosal immune barrier and inhibit STM infection. This study demonstrates that oral administration of LGG is a potential method for inhibiting STM infection.

Epigenetic regulation of innate lymphoid cells.

Innate lymphoid cells (ILCs) lack antigen-specific receptors and are considered the innate arm of the immune system, phenotypically and functionally mirroring CD4+ helper T cells. ILCs are categorized into groups 1, 2, and 3 based on transcription factors and cytokine expression. ILCs predominantly reside in mucosal tissues and play important roles in regional immune responses. The development and function of ILC subsets are controlled by both transcriptional and epigenetic mechanisms, which have been extensively studied in recent years. Epigenetic regulation refers to inheritable changes in gene expression that occur without affecting DNA sequences. This mainly includes chromatin status, histone modifications, and DNA methylation. In this review, we summarize recent discoveries on epigenetic mechanisms regulating ILC development and function, and how these regulations affect disease progression under pathological conditions. Although the ablation of specific epigenetic regulators can cause global changes in corresponding epigenetic modifications to the chromatin, only partial genes with altered epigenetic modifications change their mRNA expression, resulting in specific outcomes in cell differentiation and function. Therefore, elucidating epigenetic mechanisms underlying the regulation of ILCs will provide potential targets for the diagnosis and treatment of inflammatory diseases.

Circulating subpopulations of non-cytotoxic ILCs in diffuse large B-cell lymphoma.

Non-cytotoxic innate lymphoid cells (ILCs) have been added to the list of immune cells that may contribute to the tumor microenvironment. Elevated levels of total ILCs and their subgroups have been reported in peripheral blood and tissue samples from patients with solid tumors, but their frequency in non-Hodgkin lymphomas, particularly diffuse large B-cell lymphoma (DLBCL), has not been clearly established. This study examined frequency and subset distribution in newly diagnosed DLBCL patients (nodal and extra-nodal) and compared it with blood specimens from healthy donors. The percentage of total ILCs (Lin - CD127+) was assessed by flow cytometry, as well as the four ILC subsets, defined as ILC1 (Lin - CD127 + cKit - CRTH2-), ILC2 (Lin - CD127 + cKit+/- CRTH2+), ILCp NCR- (Lin - CD127 + cKit + CRTH2- NKp46-) and NCR + ILC3 (Lin - CD127 + cKit + NKp46+). In the studied group of patients (n = 54), significantly lower levels of circulating total ILCs, ILC1, and ILCp NCR- were observed compared to the control group (n = 43). Similarly, there was a statistically significant decrease in the median frequency of NKp46 + ILC3 cells in lymphoma patients. Analysis of the ILC2 subpopulation showed no significant differences. The correlation of the distribution of individual subpopulations of ILCs with the stage and location of the tumor was also demonstrated. Our results suggest that circulating ILCs are activated and differentiated and/or differentially recruited to the lymph nodes or tumor microenvironment where they may be involved in antitumor defense. However, our observations require confirmation in functional studies.

The role of autophagy regulated by the PI3K/AKT/mTOR pathway and innate lymphoid cells in eosinophilic chronic sinusitis with nasal polyps.

BACKGROUND: The PI3K/Akt/mTOR pathway and autophagy are important physiological processes. But their roles in eCRSwNP remains controversial. METHODS: In this study, we used the eCRSwNP mouse model, PI3K/Akt/mTOR pathway inhibitors, and autophagy inhibitors and activators to investigate the regulatory effects of the PI3K/Akt/mTOR pathway on autophagy, and their effects on eosinophilic inflammation, and tissue remodeling. The role of ILC2s in eCRSwNP was also studied, and the relationship between ILC2s and autophagy was preliminarily determined. RESULTS: Our results show that eosinophilic inflammation in eCRSwNP mice could be inhibited by promoting the autophagy; otherwise, eosinophilic inflammation could be promoted. Meanwhile, inhibition of the PI3K/Akt/mTOR pathway can further promote autophagy and inhibit eosinophilic inflammation. Meanwhile, inhibiting the PI3K/Akt/mTOR pathway and promoting autophagy can reduce the number of ILC2s and the severity of tissue remodeling in the nasal polyps of eCRSwNP mice. CONCLUSIONS: We conclude that the PI3K/Akt/mTOR pathway plays roles in eosinophilic inflammation and tissue remodeling of eCRSwNP, in part by regulating the level of autophagy. The downregulation of autophagy is a pathogenesis of eCRSwNP; therefore, the recovery of normal autophagy levels might be a new target for eCRSwNP therapy. Furthermore, autophagy might inhibit eosinophilic inflammation and tissue remodeling, in part by reducing the number of ILC2s.

Differences in intratumor innate lymphoid cell composition between orthotopic and spontaneous pancreatic mouse models.

Pancreatic cancer remains an unmet medical need. Late diagnosis and the lack of efficient treatment significantly impact the prognosis of patients suffering from pancreatic cancer. Improving patient outcomes requires a deeper comprehension of the tumor ecosystem. To achieve this, a thorough exploration of the tumor microenvironment using pre-clinical models that accurately replicate human disease is imperative, particularly in understanding the dynamics of immune cell subsets. Surprisingly, the impact of model variations on the composition of the tumor microenvironment has been largely neglected. In this study, we introduce an orthotopic model of pancreatic ductal adenocarcinoma and a spontaneous model of insulinoma. Our findings reveal striking differences in the innate lymphoid cell infiltrate, highlighting the importance of considering model-specific influences when investigating the tumor microenvironment.

Human epicardial adipose tissue contains innate and adaptive lymphoid cells and a higher proportion of innate type 2 lymphoid cells compared to other adipose tissues.

IMPORTANCE: Epicardial adipose tissue (EAT) is a biologically active organ surrounding myocardium and coronary arteries that has been associated with coronary artery disease (CAD) and atrial fibrillation. Previous work has shown that EAT exhibits beige features. OBJECTIVE: Our objective was to determine whether the stromal vascular fraction of the human EAT contains innate or adaptive lymphoid cells compared to thoracic subcutaneous (thSAT), visceral abdominal (VAT) and subcutaneous abdominal (abSAT). PARTICIPANTS: New pangenomic microarray analysis was performed on previous transcriptomic dataset using significance analysis of microarray and ingenuity pathway analysis (n=41) to identify specific immune signature and its link with browning genes. EAT, thSAT, VAT and abSAT samples from explanted patients with severe cardiomyopathies and multi-organ donor patients (n=17) were used for flow cytometry (FC) immunophenotyping assay. Patients were on average 55±16 years-old; 47% had hypertension and 6% CAD. Phenotypic adaptive and innate immune profiles were performed using a TBNK panel and a specific ILC1-2-3 panel including CD127, CD117, CRTH2 (CD294) and activation markers such as CD25 and CD69. RESULTS: Transcriptomic analysis showed a significant positive correlation between the TH2 immune pathway (IL-4, IL-5, IL-13, IL-25, IL-33) and browning genes (UCP-1, PRDM16, TMEM26, CITED1, TBX1) in EAT versus thSAT (R=0.82, P<0.0001). Regarding adaptive immune cells, a preponderance of CD8T cells, a contingent of CD4T cells, and a few B cells were observed in all ATs (P<0.0001). In innate lymphoid cells (ILCs), an increase was observed in visceral ATs (i.e. EAT; VAT 35±8ILCs/g of tissue) compared to their subcutaneous counterpart (i.e. thSAT+abSAT: 8±3 ILCs/g of AT, P=0.002), with a difference in the proportion of the 3 subtypes of ILCs (ILC1>ILC3>ILC2). In addition, we observed an increase in EAT-ILC2 compared to other ATs and almost all these EAT-ILC2 expressed CD69 and/or CD25 activation markers (99.75±0.16%; P<0.0001). We also observed more NKs in EAT and VAT (1520±71 cells/g of AT) than in SATs (562±17 cells/g of AT); P=0.01. CONCLUSION: This is the first study to provide a comparison between innate and adaptive lymphoid cells in human epicardial versus abdominal or thoracic adipose tissues. Further studies are ongoing to decipher whether these cells could be involved in EAT beiging. TRIAL REGISTRATION: CODECOH No. DC-2021-4518 The French agency of biomedicine PFS21-005.