Targeting the FcRn: A Novel Approach to the Treatment of Pemphigus

Novel Therapeutic Approach for Psoriasis: Upregulating FcRn to Inhibit Ferroptosis and Alleviate Lesional skin

Psoriasis, a chronic inflammatory skin disease, is characterized by complex immune dysregulation and oxidative stress responses. The neonatal Fc receptor (FcRn) plays a crucial role in the development of autoimmune diseases. Analysis of clinical psoriasis samples demonstrated a negative correlation between FcRn expression in skin lesions and disease severity. However, the role of FcRn in this process remains unclear. This study aimed to investigate the involvement of FcRn in the pathogenesis and progression of psoriasis. In an imiquimod(IMQ)-induced psoriasis-like mouse model, FcRn expression was significantly decreased in the lesional skin, and transcriptome sequencing of the skin revealed activation of the ferroptosis pathway in psoriasis. This led to the hypothesis that FcRn could potentially regulate ferroptosis via the signal transducer and activating transcription factor 3 (STAT3)/solute carrier family 7 member 11 (SLC7A11) axis. Further experiments showed exacerbated psoriasis-like lesional skin and ferroptosis in FcRn-knockout mice, whereas intervention with the ferroptosis inhibitor Fer-1 or STAT3 inhibitor Stattic alleviated these symptoms. Critical binding sites for the transcription factor STAT3 were identified in the SLC7A11 promoter region at positions -1185 and -564 using the luciferase reporter assays and chromatin immunoprecipitation. The administration of 1,4-naphthoquinone(NQ), an FcRn agonist, effectively alleviated psoriasis-like skin lesions by inhibiting ferroptosis. This study highlights the molecular mechanisms of action of FcRn in psoriasis and provides an experimental basis for the development of novel therapeutic strategies targeting FcRn.

What is novel in the clinical management of pemphigus vulgaris?

INTRODUCTION

Pemphigus, an uncommon autoimmune blistering disorder affecting the skin and mucous membranes, currently with mortality primarily attributed to adverse reactions resulting from treatment protocols. Additionally, the existing treatments exhibit a notable recurrence rate. The high incidence of relapse and the considerable adverse effects associated with treatment underscore the imperative to explore safer and more effective therapeutic approaches. Numerous potential therapeutic targets have demonstrated promising outcomes in trials or preliminary research stages. These encompass anti-CD-20 agents, anti-CD-25 agents, TNF-α inhibition, FAS Ligand Inhibition, FcRn inhibition, BAFF inhibition, Bruton's tyrosine kinase (BTK) inhibition, CAAR T Cells, JAK inhibition, mTOR inhibition, abatacept, IL-4 inhibition, IL-17 inhibition, IL-6 inhibition, polyclonal Regulatory T Cells, and autologous hematopoietic stem cell transplantation.

AREAS COVERED

The most significant studies regarding the impact and efficacy of the mentioned treatments on pemphigus were meticulously curated through a comprehensive search conducted on the PubMed database. Moreover, the investigations of interest cited in these studies were also integrated.

EXPERT OPINION

The efficacy and safety profiles of the other treatments under discussion do not exhibit the same level of robustness as anti-CD20 therapy, which is anticipated to endure as a critical element in pemphigus treatment well into the foreseeable future.

Targeting therapy in pemphigus: Where are we now and where are we going?

Pemphigus is a heterogeneous group of autoimmune skin disorders characterized by blistering of the skin and mucosal membranes, potentially affecting the quality of life if left unchecked. The current mainstay of treatment is systemic corticosteroids and immunosuppressive agents. Nevertheless, long-term use of these drugs can easily cause infections and other life-threatening adverse reactions. Thus, currently, researchers are trying to develop new and safer therapeutic approaches. Specifically, targeted therapies to pathogenic immune pathways have been gradually introduced and used for the treatment of pemphigus or in clinical trials, such as monoclonal anti-CD20 antibody, BAFF inhibitor, BTK inhibitor, CAAR-T therapy, FcRn antagonist, and TNF-α inhibitor. In addition, IL-4Rα antibody, IL-17 blockade, mTOR pathway inhibitor, CTLA-4Ig, and p38 MAPK inhibitors are theoretically promising treatment for pemphigus. Here, we review the research progress on the mechanism of targeted therapies for pemphigus.

Development of New Drugs for Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) is a rare disorder characterized by the autoantibody-mediated destruction of red blood cells, and treatments for it still remain challenging. Traditional first-line immunosuppressive therapy, which includes corticosteroids and rituximab, is associated with adverse effects as well as treatment failures, and relapses are common. Subsequent lines of therapy are associated with higher rates of toxicity, and some patients remain refractory to currently available treatments. Novel therapies have become promising for this vulnerable population. In this review, we will discuss the mechanism of action, existing data, and ongoing clinical trials of current novel therapies for AIHA, including B-cell-directed therapy, phagocytosis inhibition, plasma cell-directed therapy, and complement inhibition.