A p38α-BLIMP1 signalling pathway is essential for plasma cell differentiation

Derlin-3 manipulates the endoplasmic reticulum stress and IgG4 secretion of plasma cells in lung adenocarcinoma

Derlin-3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, its potential biomechanisms in the tumor microenvironment (TME) of lung adenocarcinoma (LUAD) remains to be elucidated. In the present study, we found that Derlin-3 was predominantly elevated in LUAD tissues, and could predict worse prognosis of LUAD patients. ScRNA-seq analysis indicated that Derlin-3 was mainly enriched in B lymphocytes in the TME, especially in plasma cells. Moreover, Derlin-3 may be involved in ER stress and IgG4 secretion in plasma cells by targeting Hrd1/p38/PRDM1 pathway. While the aberrant IgG4 production may be an essential driver of the polarization of macrophages towards the M2 phenotype. Additionally, downregulation of Derlin-3 could inhibit plasma cells infiltration and M2 macrophage polarization in vivo. Our results indicated that Derlin-3 could shape TME via ER stress to harness immune function, which might serve as a promising immunotherapeutic target in LUAD.

Interferon regulatory factor 4 mediates nonenzymatic IRE1 dependency in multiple myeloma cells

Multiple myeloma (MM) arises through oncogenic transformation of immunoglobulin-secreting plasma cells. MM often co-opts the central endoplasmic reticulum (ER)-stress mitigator, inositol-requiring enzyme 1 (IRE1), to sustain malignant growth. While certain MMs require enzymatic IRE1-dependent activation of the transcription factor XBP1s, others display a nonenzymatic IRE1 dependency that is not yet mechanistically understood. Here we identify interferon regulatory factor 4 (IRF4), which stimulates genes that promote immune-cell proliferation, as a key conduit for IRE1's nonenzymatic control of cell-cycle progression in MM. IRE1 silencing increased inhibitory S114/S270 phosphorylation on IRF4, disrupting IRF4's chromatin-binding and transcriptional activity. IRF4 knockdown recapitulated, whereas IRF4 repletion reversed, the anti-proliferative phenotype of IRE1 silencing. Furthermore, phospho-deficient, but not phospho-mimetic, IRF4 mutants rescued proliferation under IRE1 silencing. Functional studies revealed that IRF4 engages the E2F1 and CDC25A genes and promotes CDK2 activation to drive cell-cycle progression. Our results advance mechanistic understanding of IRE1 and IRF4 in MM.

Systems Biology Methods via Genome-Wide RNA Sequences to Investigate Pathogenic Mechanisms for Identifying Biomarkers and Constructing a DNN-Based Drug-Target Interaction Model to Predict Potential Molecular Drugs for Treating Atopic Dermatitis

This study aimed to construct genome-wide genetic and epigenetic networks (GWGENs) of atopic dermatitis (AD) and healthy controls through systems biology methods based on genome-wide microarray data. Subsequently, the core GWGENs of AD and healthy controls were extracted from their real GWGENs by the principal network projection (PNP) method for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation. Then, we identified the abnormal signaling pathways by comparing the core signaling pathways of AD and healthy controls to investigate the pathogenesis of AD. Then, IL-1β, GATA3, Akt, and NF-κB were selected as biomarkers for their important roles in the abnormal regulation of downstream genes, leading to cellular dysfunctions in AD patients. Next, a deep neural network (DNN)-based drug-target interaction (DTI) model was pre-trained on DTI databases to predict molecular drugs that interact with these biomarkers. Finally, we screened the candidate molecular drugs based on drug toxicity, sensitivity, and regulatory ability as drug design specifications to select potential molecular drugs for these biomarkers to treat AD, including metformin, allantoin, and U-0126, which have shown potential for therapeutic treatment by regulating abnormal immune responses and restoring the pathogenic signaling pathways of AD.

High-throughput CRISPR technology: a novel horizon for solid organ transplantation

Organ transplantation is the gold standard therapy for end-stage organ failure. However, the shortage of available grafts and long-term graft dysfunction remain the primary barriers to organ transplantation. Exploring approaches to solve these issues is urgent, and CRISPR/Cas9-based transcriptome editing provides one potential solution. Furthermore, combining CRISPR/Cas9-based gene editing with an ex vivo organ perfusion system would enable pre-implantation transcriptome editing of grafts. How to determine effective intervention targets becomes a new problem. Fortunately, the advent of high-throughput CRISPR screening has dramatically accelerated the effective targets. This review summarizes the current advancements, utilization, and workflow of CRISPR screening in various immune and non-immune cells. It also discusses the ongoing applications of CRISPR/Cas-based gene editing in transplantation and the prospective applications of CRISPR screening in solid organ transplantation.

The miR-17∼92 miRNAs promote plasma cell differentiation by suppressing SOCS3-mediated NIK degradation

The miR-17∼92 family microRNAs (miRNAs) play a key role in germinal center (GC) reaction through promoting T follicular helper (TFH) cell differentiation. It remains unclear whether they also have intrinsic functions in B cell differentiation and function. Here we show that mice with B cell-specific deletion of the miR-17∼92 family exhibit impaired GC reaction, plasma cell differentiation, and antibody production in response to protein antigen immunization and chronic viral infection. Employing CRISPR-mediated functional screening, we identify Socs3 as a key functional target of miR-17∼92 in regulating plasma cell differentiation. Mechanistically, SOCS3, whose expression is elevated in miR-17∼92 family-deficient B cells, interacts with NIK and promotes its ubiquitination and degradation, thereby impairing NF-κB signaling and plasma cell differentiation. This moderate increase in SOCS3 expression has little effect on IL-21-STAT3 signaling. Our study demonstrates differential sensitivity of two key signaling pathways to alterations in the protein level of an miRNA target gene.

Short-Chain Fatty Acids Alleviate Vancomycin-Caused Humoral Immunity Attenuation in Rabies-Vaccinated Mice by Promoting the Generation of Plasma Cells via Akt-mTOR Pathway

Mounting evidence suggests that gut microbial composition and its metabolites, including short-chain fatty acids (SCFAs), have beneficial effects in regulating host immunogenicity to vaccines. However, it remains unknown whether and how SCFAs improve the immunogenicity of the rabies vaccine. In this study, we investigated the effect of SCFAs on the immune response to rabies vaccine in vancomycin (Vanco)-treated mice and found that oral gavage with butyrate-producing bacteria (C. butyricum) and butyrate supplementation elevated RABV-specific IgM, IgG, and virus-neutralizing antibodies (VNAs) in Vanco-treated mice. Supplementation with butyrate expanded antigen-specific CD4+ T cells and IFN-γ-secreting cells, augmented germinal center (GC) B cell recruitment, promoted plasma cells (PCs) and RABV-specific antibody-secreting cells (ASCs) generation in Vanco-treated mice. Mechanistically, butyrate enhanced mitochondrial function and activated the Akt-mTOR pathway in primary B cells isolated from Vanco-treated mice, ultimately promoting B lymphocyte-induced maturation protein-1 (Blimp-1) expression and CD138+ PCs generation. These results highlight the important role of butyrate in alleviating Vanco-caused humoral immunity attenuation in rabies-vaccinated mice and maintaining host immune homeostasis. IMPORTANCE The gut microbiome plays many crucial roles in the maintenance of immune homeostasis. Alteration of the gut microbiome and metabolites has been shown to impact vaccine efficacy. SCFAs can act as an energy source for B-cells, thereby promoting both mucosal and systemic immunity in the host by inhibiting HDACs and activation of GPR receptors. This study investigates the impact of orally administered butyrate, an SCFA, on the immunogenicity of rabies vaccines in Vanco-treated mice. The results showed that butyrate ameliorated humoral immunity by facilitating the generation of plasma cells via the Akt-mTOR in Vanco-treated mice. These findings unveil the impact of SCFAs on the immune response of the rabies vaccine and confirm the crucial role of butyrate in regulating immunogenicity to rabies vaccines in antibiotic-treated mice. This study provides a fresh insight into the relationship of microbial metabolites and rabies vaccination.