Artemisinin attenuates IgM xenoantibody production via inhibition of T cell-independent marginal zone B cell proliferation

The roles of B cells in cardiovascular diseases

Damage to the heart can start the repair process and cause cardiac remodeling. B cells play an important role in this process. B cells are recruited to the injured place and activate cardiac remodeling through secreting antibodies and cytokines. Different types of B cells showed specific functions in the heart. Among all types of B cells, heart-associated B cells play a vital role in the heart by secreting TGFβ1. B cells participate in the activation of fibroblasts and promote cardiac fibrosis. Four subtypes of B cells in the heart revealed the relationship between the B cells' heterogeneity and cardiac remodeling. Many cardiovascular diseases like atherosclerosis, heart failure (HF), hypertension, myocardial infarction (MI), and dilated cardiomyopathy (DCM) are related to B cells. The primary mechanisms of these B cell-related activities will be discussed in this review, which may also suggest potential novel therapeutic targets.

The role of immune system in atherosclerosis: Molecular mechanisms, controversies, and future possibilities

Numerous cardiovascular disorders have atherosclerosis as their pathological underpinning. Numerous studies have demonstrated that, with the aid of pattern recognition receptors, cytokines, and immunoglobulins, innate immunity, represented by monocytes/macrophages, and adaptive immunity, primarily T/B cells, play a critical role in controlling inflammation and abnormal lipid metabolism in atherosclerosis. Additionally, the finding of numerous complement components in atherosclerotic plaques suggests yet again how heavily the immune system controls atherosclerosis. Therefore, it is essential to have a thorough grasp of how the immune system contributes to atherosclerosis. The specific molecular mechanisms involved in the activation of immune cells and immune molecules in atherosclerosis, the controversy surrounding some immune cells in atherosclerosis, and the limitations of extrapolating from relevant animal models to humans were all carefully reviewed in this review from the three perspectives of innate immunity, adaptive immunity, and complement system. This could provide fresh possibilities for atherosclerosis research and treatment in the future.

TRIM55 promotes noncanonical NF-κB signaling and B cell-mediated immune responses by coordinating p100 ubiquitination and processing

The ubiquitination-dependent processing of NF-κB2 (also known as p100) is a critical step in the activation of the noncanonical NF-κB pathway. We investigated the molecular mechanisms regulating this process and showed that TRIM55 was the E3 ubiquitin ligase that mediated the ubiquitination of p100 and coordinated its processing. TRIM55 deficiency impaired noncanonical NF-κB activation and B cell function. Mice with a B cell-specific Trim55 deficiency exhibited reduced germinal center formation and antibody production. These mice showed less severe symptoms than those of control mice upon the induction of a systemic lupus-like disease, suggesting B cell-intrinsic functions of TRIM55 in humoral immune responses and autoimmunity. Mechanistically, the ubiquitination of p100 mediated by TRIM55 was crucial for p100 processing by VCP, an ATPase that mediates ubiquitin-dependent protein degradation by the proteasome. Furthermore, we found that TRIM55 facilitated the interaction between TRIM21 and VCP as well as TRIM21-mediated K63-ubiquitination of VCP, both of which were indispensable for the formation of the VCP-UFD1-NPL4 complex and p100 processing. Together, our results reveal a mechanism by which TRIM55 fine-tunes p100 processing and regulates B cell-dependent immune responses in vivo, highlighting TRIM55 as a potential therapeutic target for lupus-like disease.

Insights into the Roles of B Cells in Patients with Sepsis

Sepsis is a life-threatening yet common disease, still posing high mortality worldwide. Sepsis-related deaths primarily occur during immunosuppression; the disease can hamper the numbers and function of B cells, which mediate innate and adaptive immune responses to maintain immune homeostasis. Dysfunction of B cells, along with aggravated immunosuppression, are closely related to poor prognosis. However, B cells in patients with sepsis have garnered little attention. This article focuses on the significance of B-cell subsets, including regulatory B cells, in sepsis and how the counts and function of circulating B cells are affected in patients with sepsis. Finally, potential B-cell-related immunotherapies for sepsis are explored.

The emerging roles and therapeutic potential of B cells in sepsis

Sepsis is a life-threatening syndrome caused by anomalous host response to infection. The pathogenesis of sepsis is complex, and immune dysfunction is the central link in its occurrence and development. The sepsis immune response is not a local and transient process but a complex and continuous process involving all major cell types of innate and adaptive immunity. B cells are traditionally studied for their ability to produce antibodies in the context of mediating humoral immunity. However, over the past few years, B cells have been increasingly recognized as key modulators of adaptive and innate immunity, and they can participate in immune responses by presenting antigens, producing cytokines, and modulating other immune cells. Recently, increasing evidence links B-cell dysfunction to mechanisms of immune derangement in sepsis, which has drawn attention to the powerful properties of this unique immune cell type in sepsis. Here, we reviewed the dynamic alterations of B cells and their novel roles in animal models and patients with sepsis, and provided new perspectives for therapeutic strategies targeting B cells in sepsis.