Prednisolone Suppresses the Extracellular Release of HMGB-1 and Associated Inflammatory Pathways in Kawasaki Disease

Immunotherapy in the context of sepsis-induced immunological dysregulation

Sepsis is a clinical syndrome caused by uncontrollable immune dysregulation triggered by pathogen infection, characterized by high incidence, mortality rates, and disease burden. Current treatments primarily focus on symptomatic relief, lacking specific therapeutic interventions. The core mechanism of sepsis is believed to be an imbalance in the host's immune response, characterized by early excessive inflammation followed by late immune suppression, triggered by pathogen invasion. This suggests that we can develop immunotherapeutic treatment strategies by targeting and modulating the components and immunological functions of the host's innate and adaptive immune systems. Therefore, this paper reviews the mechanisms of immune dysregulation in sepsis and, based on this foundation, discusses the current state of immunotherapy applications in sepsis animal models and clinical trials.

Interleukin-33/ST2 Axis as Potential Biomarker and Therapeutic Target in Kawasaki Disease

Kawasaki disease (KD) is an acute, self-limiting, febrile systemic vasculitis of unknown cause associated with the development of coronary artery lesions (CALs) during childhood. Damage-associated molecular patterns (DAMPs) from cell death and oxidative stress have been shown to be involved in the development of KD vasculitis. Interleukin (IL)-33 is released from damaged endothelial cells and acts as a DAMP. We studied whether IL-33 and its receptor (ST2) might be involved in KD pathogenesis. Serum levels of soluble ST2 (sST2) in KD patients were measured before their first therapy. Furthermore, we investigated the impact of IL-33 on human coronary artery endothelial cells (HCAECs). Serum levels of sST2 were significantly higher in KD patients with CALs than in those with normal coronary arteries. In vitro, IL-33 upregulated the expression of ST2L and increased production of sST2, IL-6, IL-8, and monocyte chemoattractant protein-1 in HCAECs in a time- and concentration-dependent manner. Moreover, IL-33 induced significantly greater production of IL-6 and IL-8 in HCAECs compared to the condition stimulated with isoconcentration of tumor necrosis factor-α. The results of the present study suggest that the IL-33/ST2 axis might be involved in the development of KD vasculitis. The IL-33/ST2 axis may be a therapeutic target for the treatment of KD.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

Role of High Mobility Group Box 1 in Cardiovascular Diseases

High Mobility Group Box 1 (HMGB1) is a ubiquitous, highly conserved nuclear and cytosolic protein that has diverse biological roles depending on its cellular location and posttranslational modifications. The HMGB1 is localized in the nucleus but can be translocated to the cytoplasm to modulate the intracellular signaling and eventually secreted outside the cells. It is widely established that HMGB1 plays a key role in inflammation; however, the role of HMGB1 in the cardiovascular diseases is not well understood. In this review, we will discuss the latest reports on the pathophysiological link between HMGB1 and cardiovascular complications, with special emphasis on the inflammation. Thus, the understanding of the role of HMGB1 may provide new insights into developing new HMGB1-based therapies.

Molecular mechanisms of endothelial dysfunction in Kawasaki-disease-associated vasculitis

Kawasaki disease (KD) is an acute, inflammation mediated vasculitis, mainly affecting in children under five, which is consider as the most common coronary artery disease in children. The injuries of coronary arteries would result in dilation or thrombus formation, bringing great threaten to patients. Endothelium, located in the inner surface of coronary artery, serves as the interface between the circulating inflammatory cells and vascular media or adventitia, which is the first target of inflammatory attacks during early stage of KD. A series of studies have determined vascular endothelial cells damages and dysfunction in KD patients. However, current therapeutic strategy is still challenging. So that it is critical to underline the mechanisms of endothelium injuries. In this review, the role of endothelial cells in the pathogenesis of KD and the therapeutic methods for endothelial cells were systematically described.

A microsatellite DNA-derived oligodeoxynucleotide attenuates lipopolysaccharide-induced acute lung injury in mice by inhibiting the HMGB1-TLR4-NF-κB signaling pathway

Acute lung injury (ALI) with uncontrolled inflammatory response has high morbidity and mortality rates in critically ill patients. Pathogen-associated molecular patterns (PAMPs) are involved in the development of uncontrolled inflammatory response injury and associated lethality. In this study, we investigated the inhibit effect of MS19, a microsatellite DNA-derived oligodeoxynucleotide (ODN) with AAAG repeats, on the inflammatory response induced by various PAMPs in vitro and in vivo. In parallel, a microsatellite DNA with AAAC repeats, named as MS19-C, was used as controls. We found that MS19 extensively inhibited the expression of inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α induced by various PAMPs stimulation, including DNA viruses, RNA viruses, bacterial components lipopolysaccharide (LPS), and curdlan, as well as the dsDNA and dsRNA mimics, in primed bone marrow-derived macrophage (BMDM). Other than various PAMPs, MS19 also demonstrated obvious effects on blocking the high mobility group box1 (HMGB1), a representative damage-associated-molecular pattern (DAMP), nuclear translocation and secretion. With the base substitution from G to C, MS19-C has been proved that it has lost the inhibitory effect. The inhibition is associated with nuclear factor kappa B (NF-κB) signaling but not the mitogen-activated protein kinase (MAPK) transduction. Moreover, MS19 capable of inhibiting the IL-6 and TNF-α production and blocking the HMGB1 nuclear translocation and secretion in LPS-stimulated cells was used to treat mice ALI induced by LPS in vivo. In the ALI mice model, MS19 significantly inhibited the weight loss and displayed the dramatic effect on lessening the ALI by reducing consolidation, hemorrhage, intra-alveolar edema in lungs of the mice. Meanwhile, MS19 could increase the survival rate of ALI by downregulating the inflammation cytokines HMGB1, TNF-a, and IL-6 production in the bronchoalveolar lavage fluid (BALF). The data suggest that MS19 might display its therapeutic role on ALI by inhibiting the HMGB1-TLR4-NF-κB signaling pathway.

Advances in understanding Kawasaki disease-related immuno-inflammatory response and vascular endothelial dysfunction

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology, which tends to involve coronary arteries and can lead to acquired heart disease in children. The immuno-inflammatory response and vascular endothelial dysfunction are important causes of coronary artery disease in patients with KD. Multisystem inflammatory syndrome in children (MIS-C) is a rare inflammatory disease in children identified in recent years, which is caused by severe acute respiratory syndrome coronavirus 2 infection; this disease overlaps with KD. This review examines research progress concerning the immuno-inflammatory response and vascular endothelial dysfunction associated with KD, as well as differences between KD and MIS-C.