A Natural Variant of the Signaling Molecule Vav1 Enhances Susceptibility to Myasthenia Gravis and Influences the T Cell Receptor Repertoire

Opposite effects of sevoflurane at high and low concentration on the airway inflammation in juvenile asthma rats: A TMT-based proteomics analysis study

BACKGROUND

The incidence of sevoflurane-related adverse respiratory events in children with asthma is notably high. During different phases of sevoflurane anesthesia, asthmatic children's airways are exposed to varying concentrations of the anesthetic. However, the specific effects of different concentrations of sevoflurane on the developing airways with asthmatic hyperreactivity have not been systematically studied.

METHODS

An ovalbumin (OVA)-induced juvenile rat asthma model was established to evaluate the impact of varying sevoflurane concentrations on airway irritation symptoms, ventilation, pathological scoring, and inflammation. Tandem mass tag (TMT)-based quantitative proteomics and bioinformatics analyses were conducted, with key protein expressions validated by western blot.

RESULTS

Sevoflurane alleviated airway irritation symptoms in OVA-treated rats in a concentration-dependent manner. At 3.2 %, sevoflurane significantly reduced peribronchial inflammation, while 0.4 % sevoflurane exacerbated hypoxia, peribronchial injury, and inflammation. Proteomic analysis identified 54 overlapping differentially expressed proteins (DEPs), with three (serine protease inhibitor (SerpinA3L), major histocompatibility complex 1 (MHC1), and major histocompatibility complex 2 (MHC2)) being upregulated in the 3.2 % sevoflurane group but downregulated in the 0.4 % sevoflurane group. DEPs were predominantly linked to lysosomal and phagosomal pathways, as well as antigen processing and presentation. Three key hub proteins-cathepsin (CAT), vav guanine nucleotide exchange factor 1 (VAV1), and C-reactive protein (CRP)-were identified, and their expression levels were validated, matching the bioinformatics analysis results.

CONCLUSIONS

Our findings demonstrate that sevoflurane exerts opposing effects on the airways of juvenile asthmatic rats, depending on the concentration. MHC1, MHC2, and VAV1 emerged as crucial mediators of these differential effects, suggesting their potential as targets for understanding sevoflurane's impact on asthmatic airways.

Immune Repertoires in Various Dermatologic and Autoimmune Diseases

The immune repertoire (IR) is a term that defines the combined unique genetic rearrangements of antigen receptors expressed by B and T lymphocytes. The IR determines the ability of the immune system to identify and respond to foreign antigens while preserving tolerance to host antigens. When immune tolerance is disrupted, development of autoimmune diseases can occur due to the attack of self-antigens. Recent technical advances in immune profiling allowed identification of common patterns and shared antigen-binding sequences unique to diverse array of diseases. However, there is no current literature to date evaluates IR findings in autoimmune and skin inflammatory conditions. In this review, we provide an overview of the past and current research findings of IR in various autoimmune and dermatologic conditions. Enriching our understanding of IRs in these conditions is critical for understanding the pathophysiology behind autoimmune skin disease onset and progression. Furthermore, understanding B-cell and T-cell IR will help devise therapeutic treatments in the hopes of restoring immune tolerance and preventing disease onset and progression.

Immune repertoire profiling in myasthenia gravis

Myasthenia gravis (MG) is the most frequent immune-mediated neurological disorder, characterized by fluctuating muscle weakness. Specific recognition of self-antigens by T-cell receptors (TCRs) and B-cell receptors (BCRs), coupled with T-B cell interactions, activates B cells to produce autoantibodies, which are critical for the initiation and perpetuation of MG. The immune repertoire comprises all functionally diverse T and B cells at a specific time point in an individual, reflecting the essence of immune selectivity. By sequencing the nucleotide sequences of TCRs and BCRs, it is possible to track individual T- and B-cell clones. This review delves into the generation of autoreactive TCRs and BCRs in MG and comprehensively examines the applications of immune repertoire sequencing in understanding disease pathogenesis, developing diagnostic and prognostic markers and informing targeted therapies. We also discuss the current limitations and future potential of this approach.

VAV1 as a putative therapeutic target in autoimmune and chronic inflammatory diseases

The guanine nucleotide exchange factor (GEF) VAV1, a previously 'undruggable' protein integral to T/B lymphocyte antigen-receptor signaling, promotes actin polymerization, immunological synapse formation, T cell activation and differentiation, and cytokine production. With the development of novel modalities for targeting proteins, we hypothesize that interventions targeting VAV1 will have therapeutic potential in T and T/B cell-mediated autoimmune and chronic inflammatory diseases. This opinion is supported by recent CRISPR-Cas9 studies showing VAV1 as a key positive regulator of T cell receptor (TCR) activation and cytokine production in primary human CD4+ and CD8+ T cells; data demonstrating that loss/suppression of VAV1 regulates autoimmunity and inflammation; and promising preclinical data from T and T/B cell-mediated disease models of arthritis and colitis showing the effectiveness of selective VAV1 targeting via protein degradation.

The Vav GEF Family: An Evolutionary and Functional Perspective

Vav proteins play roles as guanosine nucleotide exchange factors for Rho GTPases and signaling adaptors downstream of protein tyrosine kinases. The recent sequencing of the genomes of many species has revealed that this protein family originated in choanozoans, a group of unicellular organisms from which animal metazoans are believed to have originated from. Since then, the Vav family underwent expansions and reductions in its members during the evolutionary transitions that originated the agnates, chondrichthyes, some teleost fish, and some neoaves. Exotic members of the family harboring atypical structural domains can be also found in some invertebrate species. In this review, we will provide a phylogenetic perspective of the evolution of the Vav family. We will also pay attention to the structure, signaling properties, regulatory layers, and functions of Vav proteins in both invertebrate and vertebrate species.