DAPTA, a C-C Chemokine Receptor 5 (CCR5), Leads to the Downregulation of Notch/NF-κB Signaling and Proinflammatory Mediators in CD40+ Cells in Experimental Autoimmune Encephalomyelitis Model in SJL/J Mice

Macrophage Notch1 Participates in LPS-Induced Acute Lung Injury via Regulating CCR5 Expression in Mice

BACKGROUND

As pivotal immunoregulatory sentinels in pulmonary defense systems, alveolar macrophages (AMs) play dual roles in mediating inflammatory responses and tissue repair processes during various phases of inflammatory cascades. The present investigation focuses on elucidating the regulatory influence of Notch pathway activation within AM populations on the pathophysiological mechanisms underlying acute lung injury (ALI) development.

METHODS

To investigate the regulatory roles of Notch intracellular domain (NICD) and C-C chemokine receptor type 5 (CCR5) in pulmonary inflammation, an ALI model was established through lipopolysaccharide (LPS) administration. Complementary studies used macrophage-specific Notch1 knockout mice and immortalized bone marrow-derived macrophages (iBMDMs). Molecular profiling of CCR5 and inflammatory mediators was performed through real-time quantitative reverse transcription PCR (qRT-PCR) and immunofluorescence staining. Functional assessments of macrophage migration were carried out using scratch wound healing assays and transwell migration assays.

RESULTS

In the LPS-induced ALI model, pulmonary tissues exhibited elevated expression of both NICD and CCR5. Conversely, Notch1 knockout mice attenuated CCR5 expression, reduced macrophage infiltration and downregulated transcription of pro-inflammatory mediators compared to wild-type controls (p < 0.05). Lung injury was milder in the Notch1-deficient mice model compared to wild mice (p < 0.05). In vitro experiments demonstrated that inhibiting the Notch pathway in macrophages reduced CCR5 expression and attenuated CCL5-induced macrophage migration.

CONCLUSION

Notch signaling regulates macrophage infiltration and the inflammatory response by modulating CCR5 expression in ALI induced by LPS.

CD40 promotes AML survival via non-canonical NF-κB signaling and aberrant lipid metabolism

Despite the identification of several pathogenic drivers, the molecular mechanisms underlying the development of acute myeloid leukemia (AML) remain largely unknown. Therefore, we sought to explore the key genes associated with leukemia and identified cluster of differentiation 40 (CD40) as a key mediator linked to the incidence and progression of AML. Higher levels of CD40 were detected in patients with AML compared to healthy donors. Moreover, elevated CD40 expression was associated with lower overall survival rates. Furthermore, anti-CD40 antibody significantly induced apoptosis and enhanced drug sensitivity in human AML cell lines. Conversely, ex vivo treatment of primary AML samples with a CD40 agonist significantly decreased cell apoptosis and drug sensitivity. In Kasumi-1 AML cells, CD40 knockout (KO) significantly impaired the engraftment ability of leukemia cells and reduced the leukemia burden in NSG mice compared to wild-type mice. RNA sequencing showed that differentially expressed genes were significantly enriched in the nuclear factor-kB (NF-kB) signaling pathway in CD40-KO cells, which was confirmed through Western blotting. Untargeted metabolomic analysis revealed 179 metabolites with differential expression between WT and CD40 KO cells. Subsequent analysis revealed significant changes in the main metabolic pathways, particularly the biosynthesis of unsaturated fatty acids and lipid metabolism. A targeted metabolomics study of fatty acid metabolism demonstrated that cis-5, 8, 11, 14, 17-eicosapentaenoic acid (EPA) was markedly downregulated in CD40-KO cells compared to wild-type cells. Remarkably, EPA reversed the apoptosis and cell cycle arrest induced by CD40 deletion, simultaneously reducing the drug sensitivity of CD40-KO cells. Together, our study highlights the potential of CD40 as a target in the treatment of AML.

Interaction between Th17 and central nervous system in multiple sclerosis

Image 1.

Targeting the chemokines in acute graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) constitutes a critical therapeutic approach for patients with malignant hematological disorders. Nevertheless, acute graft-versus-host disease (GVHD), one of the most prevalent complications associated with HSCT, remains a leading contributor to non-relapse mortality. In recent years, there has been an increasing focus on the interplay between chemokines and their receptors in the context of acute GVHD. Chemokines exert substantial effects across various pathological conditions, including autoimmune diseases, inflammatory processes, tumorigenesis, and metastatic dissemination. In this review, we aim to elucidate the role of chemokines in the pathogenesis of acute GVHD and further understand their potential as diagnostic biomarkers. We also present both preclinical and clinical insights into the application of chemokines in preventing and treating acute GVHD. The objective of this review is to offer novel perspectives on the clinical diagnosis and management strategies for acute GVHD.

Administration of ROS-Scavenging Cerium Oxide Nanoparticles Simply Mixed with Autoantigenic Peptides Induce Antigen-Specific Immune Tolerance against Autoimmune Encephalomyelitis

The scavenging ability of cerium oxide nanoparticles (CeNPs) for reactive oxygen species has been intensively studied in the field of catalysis. However, the immunological impact of these particles has not yet been thoroughly investigated, despite intensive research indicating that modulation of the reactive oxygen species could potentially regulate cell fate and adaptive immune responses. In this study, we examined the intrinsic capability of CeNPs to induce tolerogenic dendritic cells via their reactive oxygen species-scavenging effect when the autoantigenic peptides were simply mixed with CeNPs. CeNPs effectively reduced the intracellular reactive oxygen species levels in dendritic cells in vitro, leading to the suppression of costimulatory molecules as well as NLRP3 inflammasome activation, even in the presence of pro-inflammatory stimuli. Subcutaneously administrated PEGylated CeNPs were predominantly taken up by antigen-presenting cells in lymph nodes and to suppress cell maturation in vivo. The administration of a mixture of PEGylated CeNPs and myelin oligodendrocyte glycoprotein peptides, a well-identified autoantigen associated with antimyelin autoimmunity, resulted in the generation of antigen-specific Foxp3+ regulatory T cells in mouse spleens. The induced peripheral regulatory T cells actively inhibited the infiltration of autoreactive T cells and antigen-presenting cells into the central nervous system, ultimately protecting animals from experimental autoimmune encephalomyelitis when tested using a mouse model mimicking human multiple sclerosis. Overall, our findings reveal the potential of CeNPs for generating antigen-specific immune tolerance to prevent multiple sclerosis, opening an avenue to restore immune tolerance against specific antigens by simply mixing the well-identified autoantigens with the immunosuppressive CeNPs.

CCR5 and inflammatory storm

Chemokines and their corresponding receptors play crucial roles in orchestrating inflammatory and immune responses, particularly in the context of pathological conditions disrupting the internal environment. Among these receptors, CCR5 has garnered considerable attention due to its significant involvement in the inflammatory cascade, serving as a pivotal mediator of neuroinflammation and other inflammatory pathways associated with various diseases. However, a notable gap persists in comprehending the intricate mechanisms governing the interplay between CCR5 and its ligands across diverse and intricate inflammatory pathologies. Further exploration is warranted, especially concerning the inflammatory cascade instigated by immune cell infiltration and the precise binding sites within signaling pathways. This study aims to illuminate the regulatory axes modulating signaling pathways in inflammatory cells by providing a comprehensive overview of the pathogenic processes associated with CCR5 and its ligands across various disorders. The primary focus lies on investigating the pathomechanisms associated with CCR5 in disorders related to neuroinflammation, alongside the potential impact of aging on these processes and therapeutic interventions. The discourse culminates in addressing current challenges and envisaging potential future applications, advocating for innovative research endeavors to advance our comprehension of this realm.

The Role and Therapeutic Targeting of CCR5 in Breast Cancer

The G-protein-coupled receptor C-C chemokine receptor 5 (CCR5) functions as a co-receptor for the entry of HIV into immune cells. CCR5 binds promiscuously to a diverse array of ligands initiating cell signaling that includes guided migration. Although well known to be expressed on immune cells, recent studies have shown the induction of CCR5 on the surface of breast cancer epithelial cells. The function of CCR5 on breast cancer epithelial cells includes the induction of aberrant cell survival signaling and tropism towards chemo attractants. As CCR5 is not expressed on normal epithelium, the receptor provides a potential useful target for therapy. Inhibitors of CCR5 (CCR5i), either small molecules (maraviroc, vicriviroc) or humanized monoclonal antibodies (leronlimab) have shown anti-tumor and anti-metastatic properties in preclinical studies. In early clinical studies, reviewed herein, CCR5i have shown promising results and evidence for effects on both the tumor and the anti-tumor immune response. Current clinical studies have therefore included combination therapy approaches with checkpoint inhibitors.