Mucosal pemphigus vulgaris anti-Dsg3 IgG is pathogenic to the oral mucosa of humanized Dsg3 mice

Plasma Exosomal microRNA Profile Reveals miRNA 148a-3p Downregulation in the Mucosal-Dominant Variant of Pemphigus Vulgaris

The mucosal-dominant variant of pemphigus vulgaris (MPV) is an autoimmune disease characterized by oral mucosal blistering and circulating pathogenic IgG antibodies against desmoglein 3 (Dsg3), resulting in life-threatening bullae and erosion formation. Recently, microRNAs (miRNAs) have emerged as promising players in the diagnosis and prognosis of several pathological states. For the first time, we have identified a different expression profile of miRNAs isolated from plasma-derived exosomes (P-EVs) of MPV patients positive for antibodies against Dsg3 (Dsg3-positive) compared to healthy controls. Moreover, a dysregulated miRNA profile was confirmed in MPV tissue biopsies. In particular, a strong downregulation of the miR-148a-3p expression level in P-EVs of MPV patients compared to healthy controls was demonstrated. Bioinformatics prediction analysis identifies metalloproteinase-7 (MMP7) as a potential miR-148a-3p target. An in vitro acantholysis model revealed that the miR-148a-3p expression level was dramatically downregulated after treatment with Dsg3 autoantibodies, with a concomitant increase in MMP7 expression. The increased expression of MMP7 leads to the disruption of intercellular and/or extracellular matrix adhesion in an in vitro cellular model of MPV, with subsequent cell dissociation. Overexpression of miR-148a-3p prevented cell dissociation and regressed MMP7 upregulation. Our findings suggest a pivotal role of P-EV cargo in regulating molecular mechanisms involved in MPV pathogenesis and indicate them as potential MPV therapeutic targets.

Mouse models of pemphigus: valuable tools to investigate pathomechanisms and novel therapeutic interventions

Autoimmune blistering diseases (AIBD) are paradigms of autoantibody-mediated organ-specific autoimmune disorders that involve skin and/or mucous membranes. Compared to other autoimmune diseases, the pathogenicity of autoantibodies in AIBD is relatively well described. Pemphigus is a potentially lethal autoantibody driven autoimmune disorder with a strong HLA class II association. It is mainly characterized by IgG against the desmosomal adhesion molecules desmoglein 3 (Dsg3) and Dsg1. Several murine pemphigus models were developed subsequently, each allowing the analysis of a characteristic feature, such as pathogenic IgG or Dsg3-specific T or B cells. Thus, the models can be employed to preclinically evaluate potentially novel therapies. We here thoroughly summarize past and recent efforts in developing and utilizing pemphigus mouse models for pathomechanistic investigation and therapeutic interventions.

A Keratinocyte-Tethered Biologic Enables Location-Precise Treatment in Mouse Vitiligo

Despite the central role of IFN-γ in vitiligo pathogenesis, systemic IFN-γ neutralization is an impractical treatment option owing to strong immunosuppression. However, most patients with vitiligo present with <20% affected body surface area, which provides an opportunity for localized treatments that avoid systemic side effects. After identifying keratinocytes as key cells that amplify IFN-γ signaling during vitiligo, we hypothesized that tethering an IFN-γ‒neutralizing antibody to keratinocytes would limit anti‒IFN-γ effects on the treated skin for the localized treatment. To that end, we developed a bispecific antibody capable of blocking IFN-γ signaling while binding to desmoglein expressed by keratinocytes. We characterized the effect of the bispecific antibody in vitro, ex vivo, and in a mouse model of vitiligo. Single-photon emission computed tomography/computed tomography biodistribution and serum assays after local footpad injection revealed that the bispecific antibody had improved skin retention, faster elimination from the blood, and less systemic IFN-γ inhibition than the nontethered version. Furthermore, the bispecific antibody conferred localized protection almost exclusively to the treated footpad during vitiligo, which was not possible by local injection of the nontethered anti‒IFN-γ antibody. Thus, keratinocyte tethering proved effective while significantly diminishing the off-tissue effects of IFN-γ blockade, offering a safer treatment strategy for localized skin diseases, including vitiligo.

In Vitro, Ex Vivo, and In Vivo Models for the Study of Pemphigus

Pemphigus is a life-threatening autoimmune disease. Several phenotypic variants are part of this family of bullous disorders. The disease is mainly mediated by pathogenic autoantibodies, but is also directed against two desmosomal adhesion proteins, desmoglein 1 (DSG1) and 3 (DSG3), which are expressed in the skin and mucosae. By binding to their antigens, autoantibodies induce the separation of keratinocytes, in a process known as acantholysis. The two main Pemphigus variants are Pemphigus vulgaris and foliaceus. Several models of Pemphigus have been described: in vitro, ex vivo and in vivo, passive or active mouse models. Although no model is ideal, different models display specific characteristics that are useful for testing different hypotheses regarding the initiation of Pemphigus, or to evaluate the efficacy of experimental therapies. Different disease models also allow us to evaluate the pathogenicity of specific Pemphigus autoantibodies, or to investigate the role of previously not described autoantigens. The aim of this review is to provide an overview of Pemphigus disease models, with the main focus being on active models and their potential to reproduce different disease subgroups, based on the involvement of different autoantigens.

Antigen-specific B cell depletion for precision therapy of mucosal pemphigus vulgaris

Desmoglein 3 chimeric autoantibody receptor T cells (DSG3-CAART) expressing the pemphigus vulgaris (PV) autoantigen DSG3 fused to CD137-CD3ζ signaling domains, represent a precision cellular immunotherapy approach for antigen-specific B cell depletion. Here, we present definitive preclinical studies enabling a first-in-human trial of DSG3-CAART for mucosal PV. DSG3-CAART specifically lysed human anti-DSG3 B cells from PV patients and demonstrated activity consistent with a threshold dose in vivo, resulting in decreased target cell burden, decreased serum and tissue-bound autoantibodies, and increased DSG3-CAART engraftment. In a PV active immune model with physiologic anti-DSG3 IgG levels, DSG3-CAART inhibited antibody responses against pathogenic DSG3 epitopes and autoantibody binding to epithelial tissues, leading to clinical and histologic resolution of blisters. DSG3 autoantibodies stimulated DSG3-CAART IFN-γ secretion and homotypic clustering, consistent with an activated phenotype. Toxicology screens using primary human cells and high-throughput membrane proteome arrays did not identify off-target cytotoxic interactions. These preclinical data guided the trial design for DSG3-CAART and may help inform CAART preclinical development for other antibody-mediated diseases.

[Immunomorphology of bullous lesions of the oral mucosa]

The article is devoted to the study of immunohistochemical parameters in patients with bullous lesions of the oral mucosa. The biopsy samples of the oral mucosa were studied in 57 patients, including patients with pemphigoid bullosa (38 people) and pemphigus vulgaris (19 people). The results of immunohistochemical studies indicate the cellular mechanisms of damage to the epithelium, in which IL-1, IL-6 and HPV16 are involved.

Desmoglein 3 gene mediates epidermal growth factor/epidermal growth factor receptor signaling pathway involved in inflammatory response and immune function of anaphylactic rhinitis

OBJECTIVE

To investigate the effects of desmoglein 3 (DSG3) gene mediating epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) signaling pathway on inflammatory response and immune function of anaphylactic rhinitis (AR).

METHODS

Ten of the seventy male BALB/c mice were randomly selected as the normal control group, and the remaining 60 were used to construct the AR mice model. AR model mice were divided into 6 groups: model group (instilled with 5 μL saline), empty vector group (instilled with 5 μL of liposome and empty vector mixture), siRNA-DSG3 group (instilled with 5 μL of liposome and siRNA-DSG3 carrier mixture), AG1478 group (instilled with 5 μL of EGF/EGFR inhibitor AG1478), siRNA-DSG3+AG1478 group (instilled with 5 μL of liposome and siRNA-DSG3 carrier and EGF/EGFR inhibitor AG1478 mixture) and oe-DSG3 group, 10 in each group. After taking serum, each group of mice was sacrificed to get nasal mucosa tissues. HE staining was used to observe the pathological changes of nasal mucosa tissues in each group. The expression levels of DSG3, EGF and EGFR in nasal mucosa tissues of mice in each group were detected by qRT-PCR and western blot methods respectively. TUNEL staining was used to observe the apoptosis of nasal mucosa cells in mice. The expression of IgE, INF-γ, TNF-α, IL-2, IL-4 and IL-6 in serum of mice was determined by ELISA method. The immune adhesion function of red blood cells was detected by complement sensitization yeast hemagglutination method.

RESULTS

All the mice with AR showed different degrees of nasal mucosa injury and inflammatory cell infiltration, and silencing DSG3 or inhibiting the activity of EGF signaling pathway could alleviate the nasal mucosa injury. Compared with control group, the INF-γ and IL-2 levels of serum in AR model mice were significantly decreased; IgE, TNF-α, IL-4 and IL-6 levels were significantly increased (all P < 0.05); the mRNA expression levels and protein levels of DSG3, EGF and EGFR were significantly increased (all P < 0.05); C₃b receptor rosette rate and Ic rosette rate were significantly decreased (all P < 0.05). Detected by ELISA method, the expression levels of IgE, TNF-α, IL-4 and IL-6 were increased, while the expression levels of INF-γ and IL-2 were decreased after DSG3 silencing or using AG1478. Detected by qRT-PCR and western blot methods, the expression of DSG3, EGF and EGFR did decrease after DSG3 silencing. There was no significant difference in the EGF and EGFR expression between DSG3 silencing and using AG1478, and the expression decreased even more under the double effect. The mRNA and protein expression levels of DSG3, EGF and EGFR in the nasal mucosa tissues of mice with overexpression of DSG3 plasmid were significantly higher than those of normal mice (all P < 0.05).

CONCLUSION

Silencing DSG3 gene can inhibit the activation of EGF signaling pathway, alleviate the inflammation of AR nasal mucosa, and enhance red blood cells immune adherence function.

Single-Cell Analysis Suggests that Ongoing Affinity Maturation Drives the Emergence of Pemphigus Vulgaris Autoimmune Disease

Pemphigus vulgaris (PV) is an autoimmune disease characterized by blistering sores on skin and mucosal membranes, caused by autoantibodies primarily targeting the cellular adhesion protein, desmoglein-3 (Dsg3). To better understand how Dsg3-specific autoantibodies develop and cause disease in humans, we performed a cross-sectional study of PV patients before and after treatment to track relevant cellular responses underlying disease pathogenesis, and we provide an in-depth analysis of two patients by generating a panel of mAbs from single Dsg3-specific memory B cells (MBCs). Additionally, we analyzed a paired sample from one patient collected 15-months prior to disease diagnosis. We find that Dsg3-specific MBCs have an activated phenotype and show signs of ongoing affinity maturation and clonal selection. Monoclonal antibodies (mAbs) with pathogenic activity primarily target epitopes in the extracellular domains EC1 and EC2 of Dsg3, though they can also bind to the EC4 domain. Combining antibodies targeting different epitopes synergistically enhances in vitro pathogenicity.

[Epidemiology, etiology and pathogenesis of oral mucosa bullous lesions]

OBJECTIVE Based on the data available in modern literature, to conduct a study on the epidemiology, etiology and pathogenesis of bullous lesions of the oral mucosa (pemphigus vulgaris, pemphigoid bullosa, lichen ruber planus).

MATERIAL AND METHODS

The article is based on the study of materials of foreign and domestic research databases Pubmed and Elibrary. Used literature data over the past 15 years.

RESULTS

According to domestic and foreign studies, among dermatological diseases, the most frequently detected diseases are: lichen ruber planus, pemphigoid bullosa and pemphigus vulgaris. The initial signs of these diseases are often neglected, both in patients and doctors, which leads to irreversible changes and severe course of the pathological process. In this connection, the number of patients with these lesions of the oral mucosa increases every year in all countries of the world. Bullous lesions of the oral mucosa are inflammatory and destructive diseases characterized mainly by recurrent course, variety of clinical manifestations, resistance to various therapeutic drugs. The specific features of the course of these diseases are explained both by the anatomical and physiological features of the oral mucosa, and by the etiologic and pathogenetic mechanisms of development. Currently, autoimmune processes play a leading role in the genesis of diseases, developing in response to changes in the antigenic structure of epidermal and epithelial cells under the influence of various damaging agents.

CONCLUSION

Thanks to the study, it was found that currently there are no data confirming the presence of microbial contamination of the tissues of the oral mucosa in the pathology under study. Not enough information on the factors of the immune response, in particular, on proinflammatory cytokines in the tissues of the oral mucosa.

Effect of purified fractions from cell culture supernate of high-density pre-B acute lymphoblastic leukemia cells (ALL3) on the growth of ALL3 cells at low density

The mechanisms underlying the aberrant growth and interactions between cells are not understood very well. The pre-B acute lymphoblastic leukemia cells directly obtained from an adult patient grow very poorly or do not grow at all at low density (LD), but grow better at high starting cell density (HD). We found that the LD ALL3 cells can be stimulated to grow in the presence of diffusible, soluble factors secreted by ALL3 cells themselves growing at high starting cell density. We then developed a biochemical purification procedure that allowed us to purify the factor(s) with stimulatory activity and analyzed them by nanoliquid chromatography-tandem mass spectrometry (nanoLC-MS/MS). Using nanoLC-MS/MS we have identified several proteins which were further processed using various bioinformatics tools. This resulted in eight protein candidates which might be responsible for the growth activity on non-growing LD ALL3 cells and their involvement in the stimulatory activity are discussed.

[Involvement of mucous membranes in autoimmune bullous diseases]

Autoimmune bullous diseases are characterized by intraepidermal or subepidermal autoantibody deposition that leads to blisters and secondary erosion. Mucous membranes are frequently affected in pemphigus vulgaris and always involved in cicatricial and mucosal pemphigoid. Mucosal lesions are detected less frequently in patients with bullous pemphigoid or epidermolysis bullosa acquisita. The diagnosis of autoimmune bullous disorders is based on determination of the subtype of autoantibodies bound in the skin and the clinical picture. Treatment is based on immunosuppression related to the type of disease and severity of the mucosal symptoms. Ocular involvement in mucosal pemphigoid and pemphigus vulgaris requires systemic treatment.

Reengineering chimeric antigen receptor T cells for targeted therapy of autoimmune disease

Ideally, therapy for autoimmune diseases should eliminate pathogenic autoimmune cells while sparing protective immunity, but feasible strategies for such an approach have been elusive. Here, we show that in the antibody-mediated autoimmune disease pemphigus vulgaris (PV), autoantigen-based chimeric immunoreceptors can direct T cells to kill autoreactive B lymphocytes through the specificity of the B cell receptor (BCR). We engineered human T cells to express a chimeric autoantibody receptor (CAAR), consisting of the PV autoantigen, desmoglein (Dsg) 3, fused to CD137-CD3ζ signaling domains. Dsg3 CAAR-T cells exhibit specific cytotoxicity against cells expressing anti-Dsg3 BCRs in vitro and expand, persist, and specifically eliminate Dsg3-specific B cells in vivo. CAAR-T cells may provide an effective and universal strategy for specific targeting of autoreactive B cells in antibody-mediated autoimmune disease.