B-cell-derived IL-10 promotes allergic sensitization in asthma regulated by Bcl-3

Human regulatory B cells suppress autoimmune disease primarily via interleukin-37

Regulatory B cells (Bregs) are crucial for maintaining homeostasis and controlling inflammation. Although interleukin (IL)-10 has been traditionally suggested as the primary suppressive mechanism of Bregs in both mice and humans, the key functional differences between Bregs in these two species, particularly in the context of disease, is still largely unresolved. IL-37, the latest described immunosuppressive cytokine, is produced in humans but not in mice. Herein we identified the characteristics and functions of IL-37-producing Bregs, that naturally exist in human and can be induced by recombinant IL-37 (rIL-37) and/or Toll-like receptor 9 agonist CpG via different mechanisms. rIL-37 alone is sufficient to prompt IL-37, but not IL-10, production and proliferation of Bregs, whereas CpG elicits IL-37 expression in Bregs independently of IL-10, but dependent on HIF-1α which binds on the enhancer/promoter of the IL-37 gene. Functionally, IL-37+ Bregs exhibit superior anti-inflammatory efficacy than IL-37- Bregs in vitro, as well as in psoriasis and colitis models. However, the frequency of IL-37+ Bregs is reduced in patients with psoriasis. Thus, IL-37+ Bregs hold significant therapeutic potential for treating various inflammatory disorders, including psoriasis and colitis.

The Mechanisms and Therapeutic Implications of PI3K Signaling in Airway Inflammation and Remodeling in Asthma

Bronchial asthma is a complex and heterogeneous disease with ongoing airway inflammation and increased airway responsiveness. Key characteristics of the disease include persistent airway inflammation, airway hyperresponsiveness, and airway remodeling. Asthma's chronic and recurrent characteristics contribute to airway remodeling and inflammation, which can exacerbate lung damage. Presently, inflammation is predominantly managed with corticosteroids, yet there is a notable absence of treatments specifically addressing airway remodeling. The phosphoinositide 3-kinase (PI3K) signaling pathway is integral to the processes of inflammation, airway remodeling, and immune responses. Pharmacological agents targeting this pathway are currently undergoing clinical evaluation. This review elucidates the role of PI3K in the immune responses, airway inflammation, and remodeling associated with asthma, examining its underlying mechanisms. Furthermore, we synthesize the existing literature on the therapeutic potential of PI3K inhibitors for asthma management, emphasizing immune modulation, airway inflammation, and remodeling, including drug development and ongoing clinical trials. Lastly, we explore how various PI3K-targeted therapies may enhance efficacy and improve tolerance.

Preclinical study of engineering MSCs promoting diabetic wound healing and other inflammatory diseases through M2 polarization

BACKGROUND

Diabetic foot ulcer (DFU) represents a common and severe complication of diabetes mellitus. Effective and safe treatments need to be developed. Mesenchymal stem cells (MSCs) have demonstrated crucial roles in tissue regeneration, wound repair and inflammation regulation. However, the function is limited. The safety and efficacy of gene-modified MSCs is unknown. Therefore, this study aimed to investigate whether genetically modified MSCs with highly efficient expression of anti-inflammatory factors promote diabetic wound repair by regulating macrophage phenotype transition. This may provide a new approach to treating diabetic wound healing.

METHODS

In this study, human umbilical cord-derived MSCs (hUMSCs) were genetically modified using recombinant lentiviral vectors to simultaneously overexpress three anti-inflammatory factors, interleukin (IL)-4, IL-10, IL-13 (MSCs-3IL). Cell counting kit-8, flow cytometry and differentiation assay were used to detect the criteria of MSCs. Overexpression efficiency was evaluated using flow cytometry, quantitative real-time PCR, Western blot, enzyme-linked immunosorbent assay, and cell scratch assay. We also assessed MSCs-3IL's ability to modulate Raw264.7 macrophage phenotype using flow cytometry and quantitative real-time PCR. In addition, we evaluated diabetic wound healing through healing rate calculation, HE staining, Masson staining, and immunohistochemical analysis of PCNA, F4/80, CD31, CD86, CD206, IL-4, IL-10 and IL-13. In addition, we evaluated the safety of the MSCs-3IL cells and the effect of the cells on several other models of inflammation.

RESULTS

MSCs-3IL efficiently expressed high levels of IL-4 and IL-10 (mRNA transcription increased by 15,000-fold and 800,000-fold, protein secretion 400 and 200 ng/mL), and IL-13 (mRNA transcription increased by 950,000-fold, protein secretion 6 ng/mL). MSCs-3IL effectively induced phenotypic polarization of pro-inflammatory M1-like macrophages (M1) towards anti-inflammatory M2-like macrophages (M2). The enhancement of function does not change the cell phenotype. The dynamic distribution in vivo was normal and no karyotype variation and tumor risk was observed. In a mouse diabetic wound model, MSCs-3IL promoted diabetic wound healing with a wound closure rate exceeding 96% after 14 days of cell treatment. The healing process was aided by altering macrophage phenotype (reduced CD86 and increased CD206 expression) and accelerating re-epithelialization.

CONCLUSIONS

In summary, our study demonstrates that genetically modified hUMSCs effectively overexpressed three key anti-inflammatory factors (IL-4, IL-10, IL-13). MSCs-3IL-based therapy enhances diabetic wound healing with high efficiency and safety. This suggests that genetically modified hUMSCs could be used as a novel therapeutic approach for DFU repair.

IL-10 signaling modulates PRKN methylation and influences STAT3 activity to drive regulatory macrophage differentiation

The pathogenesis of many immune disorders is linked to regulatory macrophage dysfunction. The mechanism underlying it is unclear. The objective of this study is to examine the mechanism by which the PRKN ubiquitin protein ligase (PRKN) inhibits the development of regulatory macrophages (Mreg). In this study, dust mite antigens were used as the specific allergens to establish an airway allergy (AA) mouse model. Flow cytometry cell sorting was used to isolate macrophages from the airway tissues. According to the results, the Prkn gene inhibition led to an increase in the number of Mregs in macrophages. Mregs demonstrated the capacity to suppress Th2 polarization, in which IL-10 played a critical role. Pan macrophages isolated from Prkn-deficient mice were more capable of suppressing the activities of other immune cells. PRKN was required for maintaining the hyperubiquitous status of signal transducer and transcriptional activator-3 (STAT3) in macrophages. Exposure to dust mite antigen increased the expression of PRKN in macrophages. IL-10 suppressed PRKN in macrophages by inducing its promoter hypermethylation. PRKN inhibition mitigated the experimental AA. To sum up, PRKN maintains the hyper ubiquitous status of STAT3 and restricts the expression of IL-10 in macrophages, which compromises their immune suppressive functions. Inhibition of PRKN increases Mreg development and mitigates AA. The data suggest that the regulation of Mreg has translation potential to be used in the treatment of immune disorders such as AA.

IL-33 signaling is dispensable for the IL-10-induced enhancement of mast cell responses during food allergy

Background

The IL-33/ST2 axis plays a pivotal role in the development of IgE-mediated mast cell (MC) responses during food allergy. We recently demonstrated that the pleiotropic cytokine, IL-10, not only exerts proinflammatory effects on IgE-mediated MC activation, but also promotes IL-33-induced MC responses. However, whether IL-33 is necessary for IL-10's proinflammatory effects has not been examined.

Methods

To therefore determine the role of the IL-33/ST2 axis in this pathway, we assessed the effects of IL-10 on IgE-mediated MC activation and food allergy development in wild-type (WT) and ST2-/- mice.

Results

IL-10 stimulation significantly enhanced IL-33 gene expression, ST2 receptor expression, cytokine production, mMCP-1 secretion, and proliferation in IgE and antigen-activated bone marrow-derived MCs (BMMCs) from WT mice. ST2-/- BMMCs exhibited reduced cytokine secretion in response to IgE-dependent activation. However, IL-10 enhanced cytokine production, mMCP-1 secretion, and proliferation in these cells as well. To further assess the role of IL-10, food allergy was induced in WT and ST2-/- mice subjected to antibody-mediated IL-10 depletion. IL-10-depleted WT mice exhibited a significant attenuation in MC-mediated responses to OVA challenge. While ST2-/- mice also exhibited a profound suppression of MC responses, IL-10 depletion had no additional effects. However, ST2-/-/IL-10-/- mice exhibited further decreases in OVA-IgE and antigen-specific MC activation compared to ST2-/- mice.

Conclusion

Our data demonstrates that IL-10 can enhance MC responses in both WT and ST2-/- mice, further corroborating its proinflammatory effects on MCs and suggesting that they are not regulated by IL-33 signaling.

Elucidating the causal associations and mechanisms between circulating immune cells and idiopathic pulmonary fibrosis: new insights from Mendelian randomization and transcriptomics

Background

Growing evidence indicates an association between circulating immune cell phenotypes and idiopathic pulmonary fibrosis (IPF). Although studies have attempted to elucidate the causal relationship between the two, further clarification of the specific mechanisms and causal linkages is warranted.

Objective

We aimed to conduct a two-sample Mendelian randomization (MR) analysis with transcriptomics data analysis to elucidate the causal relationship between circulating immune cells and IPF and to explore potential biomarkers.

Methods

We first explored the bidirectional causal association between IPF and immune cell phenotypes using two-sample MR analysis. Genome-wide association studies data for immune cell phenotype and IPF were obtained from publicly available databases. A standardized instrumental variable screening process was used to select single nucleotide polymorphisms (SNPs) for inclusion in the MR. Five methods represented by IVW were used to assess causal effects. Subsequently, SNP-nearest genes combined with the transcriptomics data of IPF were subjected to multiple bioinformatics analyses such as TIMER, WGCNA, functional enrichment analysis, protein-protein interaction analysis, and ROC to identify IPF biomarkers. Finally, the single-cell RNA sequencing (scRNA-seq) data was used to validate our findings by single-cell analysis.

Results

The MR study identified 27 immune cell phenotypes causally associated with IPF, of which 20 were associated with a decreased risk of developing IPF and 7 were associated with an increased risk. CTSB (AUC=0.98), IL10 (AUC=0.83), and AGER (AUC=0.87) were identified as promising biomarkers of IPF. Single cell analysis showed differences in CD14+ CD16+ monocytes, CD16+ monocytes and Granulocyte-monocyte progenito between the IPF group and the healthy control group. The three hub genes were highly expressed in three immune cell subsets of IPF patients. It underscores the potential feasibility of three genes as biomarkers.

Conclusions

Our study demonstrates the causal associations of specific immune cell phenotypes with IPF through genetic methods and identifies CTSB, IL10, and AGER as biomarkers of IPF through bioinformatics analysis. These findings provide guidance for future clinical and basic research.

Targeting mitochondrial function as a potential therapeutic approach for allergic asthma

Allergic asthma is a chronic complex airway disease characterized by airway hyperresponsiveness, eosinophilic inflammation, excessive mucus secretion, and airway remodeling, with increasing mortality and incidence globally. The pathogenesis of allergic asthma is influenced by various factors including genetics, environment, and immune responses, making it complex and diverse. Recent studies have found that various cellular functions of mitochondria such as calcium regulation, adenosine triphosphate production, changes in redox potential, and free radical scavenging, are involved in regulating the pathogenesis of asthma. This review explores the involvement of mitochondrial functional changes in the pathogenesis of asthma, and investigate the potential of targeting cellular mitochondria as a therapeutic approach for asthma. Those insights can provide a novel theoretical foundations and treatment strategies for understanding and preventing asthma.

The Role of Regulatory B Lymphocytes in Allergic Diseases

PURPOSE OF REVIEW

Regulatory B cells (Bregs) are a key component in the regulation of the immune system. Their immunosuppressive function, which includes limiting the inflammatory cascade, occurs through interactions with other immune cells and the secretion of cytokines, primarily IL-10. As knowledge about B cells continues to expand, their diversity is becoming more recognized, with many subpopulations identified in both human and animal models. However, identifying specific transcription factors or markers that could definitively distinguish regulatory B cells remains a challenge. This review summarizes recent findings on the role of B regulatory cells in allergic diseases.

RECENT FINDINGS

In patients with bronchial asthma, atopic dermatitis, and food allergies, the number of regulatory B cells is reduced, and disease severity is inversely proportional to the quantity of these cells. Furthermore, in patients with atopic dermatitis, the ability of regulatory B cells to produce IL-10 in response to IL-6 stimulation is diminished. However, allergen immunotherapy has been shown to induce the formation of regulatory T cells as well as regulatory B cells.

SUMMARY

The success of future therapies based on B cells may depend on deepening our current understanding of their phenotypes, induction, differentiation, and function. Research in these areas is essential for understanding the mechanisms regulating Breg activity and for developing potential targeted therapies in the treatment of allergic diseases.

The role of DC subgroups in the pathogenesis of asthma

Dendritic cells (DCs), specialized antigen-presenting cells of the immune system, act as immunomodulators in diseases of the immune system, including asthma. The understanding of DC biology has evolved over the years to include multiple subsets of DCs with distinct functions in the initiation and maintenance of asthma. Moreover, most strategies for treating asthma with relevant therapeutic agents that target DCs have been initiated from the study of DC function. We discussed the pathogenesis of asthma (including T2-high and T2-low), the roles played by different DC subpopulations in the pathogenesis of asthma, and the therapeutic strategies centered around DCs. This study will provide a scientific theoretical basis for current asthma treatment, provide theoretical guidance and research ideas for developing and studying therapeutic drugs targeting DC, and provide more therapeutic options for the patient population with poorly controlled asthma symptoms.

Deciphering the molecular nexus between Omicron infection and acute kidney injury: a bioinformatics approach

Background

The ongoing global health crisis of COVID-19, and particularly the challenges posed by recurrent infections of the Omicron variant, have significantly strained healthcare systems worldwide. There is a growing body of evidence indicating an increased susceptibility to Omicron infection in patients suffering from Acute Kidney Injury (AKI). However, the intricate molecular interplay between AKI and Omicron variant of COVID-19 remains largely enigmatic.

Methods

This study employed a comprehensive analysis of human RNA sequencing (RNA-seq) and microarray datasets to identify differentially expressed genes (DEGs) associated with Omicron infection in the context of AKI. We engaged in functional enrichment assessments, an examination of Protein-Protein Interaction (PPI) networks, and advanced network analysis to elucidate the cellular signaling pathways involved, identify critical hub genes, and determine the relevant controlling transcription factors and microRNAs. Additionally, we explored protein-drug interactions to highlight potential pharmacological interventions.

Results

Our investigation revealed significant DEGs and cellular signaling pathways implicated in both Omicron infection and AKI. We identified pivotal hub genes, including EIF2AK2, PLSCR1, GBP1, TNFSF10, C1QB, and BST2, and their associated regulatory transcription factors and microRNAs. Notably, in the murine AKI model, there was a marked reduction in EIF2AK2 expression, in contrast to significant elevations in PLSCR1, C1QB, and BST2. EIF2AK2 exhibited an inverse relationship with the primary AKI mediator, Kim-1, whereas PLSCR1 and C1QB demonstrated strong positive correlations with it. Moreover, we identified potential therapeutic agents such as Suloctidil, Apocarotenal, 3'-Azido-3'-deoxythymidine, among others. Our findings also highlighted a correlation between the identified hub genes and diseases like myocardial ischemia, schizophrenia, and liver cirrhosis. To further validate the credibility of our data, we employed an independent validation dataset to verify the hub genes. Notably, the expression patterns of PLSCR1, GBP1, BST2, and C1QB were consistent with our research findings, reaffirming the reliability of our results.

Conclusion

Our bioinformatics analysis has provided initial insights into the shared genetic landscape between Omicron COVID-19 infections and AKI, identifying potential therapeutic targets and drugs. This preliminary investigation lays the foundation for further research, with the hope of contributing to the development of innovative treatment strategies for these complex medical conditions.

IL-10 Neutralization Attenuates Mast Cell Responses in a Murine Model of Experimental Food Allergy

IgE-mediated mast cell (MC) activation is a critical component of allergic responses to oral Ags. Several T cell-derived cytokines have been shown to promote MC reactivity, and we recently demonstrated a critical role for the cytokine IL-10 in mediating MC responses during food allergy. In this study, we further validate the role of IL-10 using Ab-mediated IL-10 depletion. IL-10 neutralization significantly attenuated MC responses, leading to decreased MC accumulation and activation, as well as inhibition of MC-mediated symptoms such as allergic diarrhea. This was accompanied by decreased Th2 cytokine gene expression, attenuated systemic T cell responses, and fewer CD4 T cells, B cells, and MCs in the spleen. Our data further confirm the role of IL-10 in driving MC responses and suggest that IL-10-responsive MCs may constitute an important player in allergic responses.

The role of regulatory B cells in immune regulation and childhood allergic asthma

BACKGROUND

As the most common chronic disease in childhood, asthma displays a major public health problem worldwide with the incidence of those affected rising. As there is currently no cure for allergic asthma, it is mandatory to get a better understanding of the underlying molecular mechanism.

MAIN BODY

By producing IgE antibodies upon allergen contact, B cells play a pivotal role in allergic asthma. Besides that, IL-10-secreting B cell subsets, namely regulatory B cells (Bregs), are reported in mice and humans to play a role in allergic asthma. In humans, several Breg subsets with distinct phenotypic and functional properties are identified among B cells at different maturational and differentiation stages that exert anti-inflammatory functions by expressing several suppressor molecules. Emerging research has focused on the role of Bregs in allergic asthma as well as their role for future diagnostic and preventive strategies.

CONCLUSION

Knowledge about the exact function of human Bregs in allergic asthma is still very limited. This review aims to summarize the current knowledge on Bregs. We discuss different human Breg subsets, several ways of Breg induction as well as the mechanisms through which they exert immunoregulatory functions, and their role in (childhood) allergic asthma.