IL-21 impairs pro-inflammatory activity of M1-like macrophages exerting anti-inflammatory effects on rheumatoid arthritis

Recent advances in potential targets for myocardial ischemia reperfusion injury: Role of macrophages

Myocardial ischemia-reperfusion injury (MIRI) is a complex process that occurs when blood flow is restored after myocardium infarction (MI) with exacerbated tissue damage. Macrophages, essential cell type of the immune response, play an important role in MIRI. Macrophage subpopulations, namely M1 and M2, are distinguished by distinct phenotypes and functions. In MIRI, macrophages infiltrate in infarcted area, shaping the inflammatory response and influencing tissue healing. Resident cardiac macrophages interact with monocyte-derived macrophages in MIRI, and influence injury progression. Key factors including chemokines, cytokines, and toll-like receptors modulate macrophage behavior in MIRI. This review aims to address recent findings on the classification and the roles of macrophages in the myocardium, spanning from MI to subsequent MIRI, and highlights various signaling pathways implicated in macrophage polarization underlining the complexity of MIRI. This article will shed light on developing advanced therapeutic strategies for MIRI management.

The role of Interleukin-21 in autoimmune Diseases: Mechanisms, therapeutic Implications, and future directions

IL-21 is a multifunctional cytokine that regulates the functional activity of various immune cells. Initial studies have shown that IL-21 can influence the differentiation, proliferation and function of T and B cells, as well as promote the maturation and increase the cytotoxicity of CD8 + T cells and NK cells. During humoral immune responses, IL-21 has significant effects on B cell activation, differentiation and apoptosis. In addition, IL-21 promotes the differentiation of both naive and memory B cells, ultimately leading to the activation of plasma cells. The function of IL-21 in the immune system is complex, as it has the ability to either stimulate or inhibit immune responses. in addition, IL-21 facilitates the differentiation of naive and memory B cells into plasma cells. The functionality of IL-21 in the immune system is diverse, as it has the ability to stimulate or inhibit immune responses. This cytokine has been implicated in several diseases including cancer, allergies and autoimmune diseases. Research has suggested that this cytokine is involved in the development of autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Several studies have suggested that inhibition of IL-21 has a therapeutic effect on autoimmune diseases. Therefore, targeting both the cytokine's receptor and IL-21 in autoimmune diseases may be an effective approach to reduce the severity of the disease or to treat it. This review will examine the biological effects of IL-21 on various immune cells and the role of the cytokine in autoimmune diseases.

IL-21/IL-21R Promotes the Pro-Inflammatory Effects of Macrophages during C. muridarum Respiratory Infection

Interleukin-21 and its receptors (IL-21/IL-21R) aggravate chlamydial lung infection, while macrophages (Mφ) are one of the main cells infected by chlamydia and the main source of inflammatory cytokines. Therefore, it is particularly important to study whether IL-21/IL-21R aggravates chlamydia respiratory infection by regulating Mφ. Combined with bioinformatics analysis, we established an IL-21R-deficient (IL-21R-/-) mouse model of Chlamydia muridarum (C. muridarum) respiratory tract infection in vivo, studied C. muridarum-stimulated RAW264.7 by the addition of rmIL-21 in vitro, and conducted adoptive transfer experiments to clarify the association between IL-21/IL-21R and Mφ. IL-21R-/- mice showed lower infiltration of pulmonary total Mφ, alveolar macrophages, and interstitial macrophages compared with WT mice following infection. Transcriptomic analysis suggested that M1-related genes are downregulated in IL-21R-/- mice and that IL-21R deficiency affects the Mφ-mediated inflammatory response during C. muridarum infection. In vivo experiments verified that in IL-21R-/- mice, pulmonary M1-type CD80+, CD86+, MHC II+, TNFα+, and iNOS+ Mφ decreased, while there were no differences in M2-type CD206+, TGF-β+, IL-10+ and ARG1+ Mφ. In vitro, administration of rmIL-21 to C. muridarum-stimulated RAW264.7 cells promoted the levels of iNOS-NO and the expression of IL-12p40 and TNFα, but had no effect on TGFβ or IL-10. Further, adoptive transfer of M1-like bone marrow-derived macrophages derived from IL-21R-/- mice, unlike those from WT mice, effectively protected the recipients against C. muridarum infection and induced relieved pulmonary pathology. These findings help in understanding the mechanism by which IL-21/IL-21R exacerbates chlamydia respiratory infection by promoting the proinflammatory effect of Mφ.

Biological Insight and Recent Advancement in the Treatment of Neuroblastoma

One of the most frequent solid tumors in children is neuroblastoma, which has a variety of clinical behaviors that are mostly influenced by the biology of the tumor. Unique characteristics of neuroblastoma includes its early age of onset, its propensity for spontaneous tumor regression in newborns, and its high prevalence of metastatic disease at diagnosis in individuals older than 1 year of age. Immunotherapeutic techniques have been added to the previously enlisted chemotherapeutic treatments as therapeutic choices. A groundbreaking new treatment for hematological malignancies is adoptive cell therapy, specifically chimeric antigen receptor (CAR) T cell therapy. However, due to the immunosuppressive nature of the tumor microenvironment (TME) of neuroblastoma tumor, this treatment approach faces difficulties. Numerous tumor-associated genes and antigens, including the MYCN proto-oncogene (MYCN) and disialoganglioside (GD2) surface antigen, have been found by the molecular analysis of neuroblastoma cells. The MYCN gene and GD2 are two of the most useful immunotherapy findings for neuroblastoma. The tumor cells devise numerous methods to evade immune identification or modify the activity of immune cells. In addition to addressing the difficulties and potential advancements of immunotherapies for neuroblastoma, this review attempts to identify important immunological actors and biological pathways involved in the dynamic interaction between the TME and immune system.

Cytokine sustained delivery for cancer therapy; special focus on stem cell- and biomaterial- based delivery methods

As immune regulators, cytokines serve critical role as signaling molecules in response to danger, tissue damage, or injury. Importantly, due to their vital role in immunological surveillance, cytokine therapy has become a promising therapeutics for cancer therapy. Cytokines have, however, been used only in certain clinical settings. Two key characteristics of cytokines contribute to this clinical translational challenge: first, they are highly pleiotropic, and second, in healthy physiology, they are typically secreted and act very locally in tissues. Systemic administration of the cytokines can consequently result in serious side effects. Thus, scientists have sought various strategies to circumvent theses hurdles. Recent in vivo reports signify that cytokine delivery platforms can increase their safety and therapeutic efficacy in tumor xenografts. Meanwhile, cytokine delivery using multipotent stem cells, in particular mesenchymal stem/stromal cells (MSCs), and also a diversity of particles and biomaterials has demonstrated greater capability in this regards. Herein, we take a glimpse into the recent advances in cytokine sustained delivery using stem cells and also biomaterials to ease safe and effective treatments of a myriad of human tumors.

Geniposide inhibits SphK1 membrane targeting to restore macrophage polarization balance in collagen-induced arthritis mice

Imbalance of macrophage polarization plays a critical role in the progression of rheumatoid arthritis (RA). Geniposide (GE) has been shown to exert anti-inflammatory effects. However, the effect of GE on macrophage polarization remains unclear. Here, we investigated the regulation of GE on the imbalance of macrophage polarization in RA and how it functions. We established a mouse model of collagen-induced arthritis (CIA) and isolated bone marrow-derived macrophages (BMDMs). The results confirmed that pro-inflammatory M1 macrophages were dominant in CIA mice, but the polarization imbalance of macrophages was restored to a certain extent after GE treatment. Furthermore, the membrane targeting of sphingosine kinase 1 (SphK1) was increased in BMDMs of CIA mice, as manifested by increased membrane and cytoplasmic expression of p-SphK1 and high secretion level of sphingosine-1-phosphate (S1P). RAW264.7 cells were stimulated with lipopolysaccharide (LPS)-interferon (IFN)-γ or interleukin (IL)-4 to induce M1 or M2 phenotype, respectively, to revalidate the results obtained in BMDMs. The results again observed SphK1 membrane targeting in LPS-IFN-γ-stimulated RAW264.7 cells. Selective inhibition of SphK1 by PF543 or inhibition of the S1P receptors by FTY720 both restored the proportion of M1 and M2 macrophages in LPS-IFN-γ-stimulated RAW264.7 cells, confirming that SphK1 membrane targeting mediated a proportional imbalance in M1 and M2 macrophage polarization. In addition, GE inhibited SphK1 membrane targeting and kinase activity. Taken together, results confirmed that the inhibition of SphK1 membrane targeting by GE was responsible for restoring the polarization balance of macrophages in CIA mice.

The Role of M1/M2 Macrophage Polarization in Rheumatoid Arthritis Synovitis

Innate and adaptive immunity represent a harmonic counterbalanced system involved in the induction, progression, and possibly resolution of the inflammatory reaction that characterize autoimmune rheumatic diseases (ARDs), including rheumatoid arthritis (RA). Although the immunopathophysiological mechanisms of the ARDs are not fully clarified, they are often associated with an inappropriate macrophage/T-cell interaction, where classical (M1) or alternative (M2) macrophage activation may influence the occurrence of T-helper (Th)1 or Th2 responses. In RA patients, M1/Th1 activation occurs in an inflammatory environment dominated by Toll-like receptor (TLR) and interferon (IFN) signaling, and it promotes a massive production of pro-inflammatory cytokines [i.e., tumor necrosis factor-α (TNFα), interleukin (IL)-1, IL-12, IL-18, and IFNγ], chemotactic factors, and matrix metalloproteinases resulting in osteoclastogenesis, erosion, and progressive joint destruction. On the other hand, the activation of M2/Th2 response determines the release of growth factors and cytokines [i.e., IL-4, IL-10, IL-13, and transforming growth factor (TGF)-β] involved in the anti-inflammatory process leading to the clinical remission of RA. Several subtypes of macrophages have been described. Five polarization states from M1 to M2 have been confirmed in in vitro studies analyzing morphological characteristics, gene expression of phenotype markers (CD80, CD86, TLR2, TLR4, or CD206, CD204, CD163, MerTK), and functional aspect, including the production of reactive oxygen species (ROS). An M1 and M2 macrophage imbalance may induce pathological consequences and contribute to several diseases, such as asthma or osteoclastogenesis in RA patients. In addition, the macrophage dynamic polarization from M1 to M2 includes the presence of intermediate polarity stages distinguished by the expression of specific surface markers and the production/release of distinct molecules (i.e., nitric oxide, cytokines), which characterize their morphological and functional state. This suggests a “continuum” of macrophage activation states playing an important role during inflammation and its resolution. This review discusses the importance of the delicate M1/M2 imbalance in the different phases of the inflammatory process together with the identification of specific pathways, cytokines, and chemokines involved, and its clinical outcomes in RA. The analysis of these aspects could shed a light on the abnormal inflammatory activation, leading to novel therapeutical approaches which may contribute to restore the M1/M2 balance.

T peripheral helper cells in autoimmune diseases

Pathologic T cell-B cell interactions underlie many autoimmune diseases. The T cells that help B cells in autoimmune diseases vary in phenotype and include T cells that lack typical features of T follicular helper cells, such as expression of CXCR5 and BCL6. A population of PD-1hi CXCR5- T peripheral helper (Tph) cells has now been recognized in multiple autoantibody-associated diseases. Tph cells display a distinctive set of features, merging the ability to provide B cell help with the capacity to migrate to inflamed peripheral tissues. Here, we review the scope of immune-related conditions in which Tph cells have been implicated and provide a perspective on their potential contributions to pathologic B cell activation in autoimmune diseases. We discuss Tph cells as a promising therapeutic strategy in autoimmunity and consider the utility of tracking Tph cells in blood as a biomarker to quantify aberrant T cell-B cell activation in patients with autoimmune diseases.