Dexmedetomidine postconditioning alleviates spinal cord ischemia-reperfusion injury in rats via inhibiting neutrophil infiltration, microglia activation, reactive gliosis and CXCL13/CXCR5 axis activation.

PURPOSE: Spinal cord ischemia-reperfusion (I/R) injury is an unresolved complication and its mechanisms are still not completely understood. Here, we studied the neuroprotective effects of dexmedetomidine (DEX) postconditioning against spinal cord I/R injury in rats and explored the possible mechanisms. MATERIALS AND METHODS: In the study, rats were randomly divided into five groups: sham group, I/R group, DEX0.5 group, DEX2.5 group, and DEX5 group. I/R injury was induced in experimental rats; 0.5 µg/kg, 2.5 µg/kg, 5 µg/kg DEX were intravenously injected upon reperfusion respectively. Neurological function, histological assessment, and the disruption of blood-spinal cord barrier (BSCB) were evaluated via the BBB scoring, hematoxylin and eosin staining, Evans Blue (EB) extravasation and spinal cord edema, respectively. Neutrophil infiltration was evaluated via Myeloperoxidase (MPO) activity. Microglia activation and reactive gliosis was evaluated via ionized calcium-binding adapter molecule-1(IBA-1) and glial fibrillary acidic protein (GFAP) immunofluorescence, respectively. The expression of C-X-C motif ligand 13 (CXCL13), C-X-C chemokine receptor type 5(CXCR5), caspase-3 was determined by western blotting. The expression levels of interleukin 6(IL-6), tumor necrosis factor-α(TNF-α), IL-1ß were determined by ELISA assay. RESULTS: DEX postconditioning preserved neurological assessment scores, improved histological assessment scores, attenuated BSCB leakage after spinal cord I/R injury. Neutrophil infiltration, microglia activation and reactive gliosis were also inhibited by DEX postconditioning. The expression of CXCL13, CXCR5, caspase-3, IL-6, TNF-α, IL-1ß were reduced by DEX postconditioning. CONCLUSIONS: DEX postconditioning alleviated spinal cord I/R injury, which might be mediated via inhibition of neutrophil infiltration, microglia activation, reactive gliosis and CXCL13/CXCR5 axis activation.

Phase I Clinical Trial of CD19 CAR-T Cells Expressing CXCR5 Protein for the Treatment of Relapsed or Refractory B-cell Lymphoma.

BACKGROUND: It is difficult for CD19 CAR-T cells to enter solid tumors, which is one reason for their poor efficacy in lymphoma treatment. The chemokine CXCL13 secreted by stro-mal cells of the lymph nodes induces the homing of B and T lymphocytes, which express its receptor CXCR5. Preclinical trials have shown that the expression of CXCR5 on CD19 CAR-T cells can increase their migration to the tumor microenvironment and enhance their antitumor function. METHODS: We engineered the CD19 CAR-T cells to express a second receptor, CXCR5. Then, we conducted a phase I clinical trial to evaluate the safety and efficacy of CXCR5 CD19 CAR-T cells in the treatment of relapsed or refractory (R/R) B-cell lymphoma. RESULTS: We recruited 10 patients with R/R B-cell lymphoma undergoing CXCR5 CD19 CAR-T cell therapy. The objective response rate was 80%, and the complete response rate was 50%. The median follow-up time was 15.48 months (3.4-22.3 months), and the median Progression-Free Survival (PFS) time was 8.15 months (1.5-22.33 months). One patient received ASCT at 1.5 months (at PR) after infusion of CAR-T cells. The incidence of grade 1 and grade 2 Cytokine Release Syndrome (CRS) was 70% and 20%, respectively. No patient experienced grade 3 or higher levels of CRS, neurotoxicity, or infusion-related dose toxicity. CONCLUSION: The results obtained in this study suggest that CXCR5 CD19 CAR-T cells should be investigated in a trial with broader patient populations. TRIAL REGISTRATION: The trials were registered at www.chictr.org.cn as ChiCTR2100052677 and ChiCTR1900028692.

CXCL13-CXCR5 axis: Regulation in inflammatory diseases and cancer.

Chemokine C-X-C motif ligand 13 (CXCL13), originally identified as a B-cell chemokine, plays an important role in the immune system. The interaction between CXCL13 and its receptor, the G-protein coupled receptor (GPCR) CXCR5, builds a signaling network that regulates not only normal organisms but also the development of many diseases. However, the precise action mechanism remains unclear. In this review, we discussed the functional mechanisms of the CXCL13-CXCR5 axis under normal conditions, with special focus on its association with diseases. For certain refractory diseases, we emphasize the diagnostic and therapeutic role of CXCL13-CXCR5 axis.

Potential Role of CXCL13/CXCR5 Signaling in Immune Checkpoint Inhibitor Treatment in Cancer.

Immune checkpoint inhibitors (ICIs), including antibodies that target programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), or cytotoxic T lymphocyte antigen 4 (CTLA4), represent some of the most important breakthroughs in new drug development for oncology therapy from the past decade. CXC chemokine ligand 13 (CXCL13) exclusively binds CXC chemokine receptor type 5 (CXCR5), which plays a critical role in immune cell recruitment and activation and the regulation of the adaptive immune response. CXCL13 is a key molecular determinant of the formation of tertiary lymphoid structures (TLSs), which are organized aggregates of T, B, and dendritic cells that participate in the adaptive antitumor immune response. CXCL13 may also serve as a prognostic and predictive factor, and the role played by CXCL13 in some ICI-responsive tumor types has gained intense interest. This review discusses how CXCL13/CXCR5 signaling modulates cancer and immune cells to promote lymphocyte infiltration, activation by tumor antigens, and differentiation to increase the antitumor immune response. We also summarize recent preclinical and clinical evidence regarding the ICI-therapeutic implications of targeting the CXCL13/CXCR5 axis and discuss the potential role of this signaling pathway in cancer immunotherapy.

Alleviating effect of paeoniflorin-6'-O-benzene sulfonate in antigen-induced experimental Sjögren's syndrome by modulating B lymphocyte migration via CXCR5-GRK2-ERK/p38 signaling pathway.

Primary Sjögren's syndrome (pSS) is an autoimmune disease of unresolved aetiology that affects the exocrine glands. Clinical symptoms frequently also involve skin, liver, kidney and neurovascular components. The pathogenesis of pSS is still unclear but B cell hyperactivity has been identified as a hallmark of pSS. Currently, a curative therapeutic agent is lacking. In this study, we explored whether paeoniflorin-6'-O-benzene (CP-25) exerted therapeutic effects through regulating B lymphocyte migration via CXCR5-GRK2-MAPK mediated signaling pathways in a mouse model of antigen-induced, experimental Sjögren's syndrome (ESS). We found that CP-25 increased the salivary flow and alleviated the histopathology of ESS. Furthermore, CP-25 reduced the viability of B lymphocyte and limited the target organs index. In the peripheral blood and salivary gland of ESS mice, CP-25 down-regulated the proportion of total B cells, CXCR5+ B cells and PDCA1 + CD19- and limited the presence of phosphorylated (p-) p38 and ERK (p-ERK). Besides, CP-25 increased the percentage of memory B cells in the peripheral blood and reduced it in salivary gland. Furthermore, in vitro, CP-25 down-regulated p-p38, p-ERK, CXCR5 and membrane GRK2, and increased cytoplasm GRK2 in Maver-1 cells, a mantle cell lymphoma cell line, causing a lower migration ability of Maver-1 cells. Thus, we define CP-25 as a novel compound that is a potent therapeutic agent for pSS which modulates B lymphocyte subsets and impacts the migration of B lymphocytes through regulating the CXCR5-GRK2-ERK/p38 signaling pathway.

RelA driven co-expression of CXCL13 and CXCR5 is governed by a multifaceted transcriptional program regulating breast cancer progression.

Lethal metastasis of primary breast tumors to lymph nodes has been found to be associated with the co-expression of chemokine CXCL13 and its receptor CXCR5. To date, however, the precise molecular events regulating the co-expression of CXCL13 and CXCR5 in the context of breast cancer progression have not been identified. Therefore, to extend our understanding of the drivers of breast cancer metastasis, we undertook a line of investigation in this study in which we demonstrate that the transcriptional regulation of CXCL13 is mediated by the reciprocal activity of RelA and Nrf2, while CXCR5 is transcriptionally silenced by CpG island methylation within its promoter. Critically, we show that intra-tumoral CXCL13 and CXCR5 mRNA expression is positively correlated with intra-tumoral RelA expression within the primary tumor of breast cancer (BCa) patients (n = 98). We demonstrate a role for Nrf2 in the negative transcriptional regulation of cxcl13. Furthermore, using a luciferase assay and deletion analysis of the cxcl13 gene promoter, we demonstrate that RelA and Nrf2 directly act upon the cxcl13 promoter to regulate transcription. Chromatin immunoprecipitation PCR, supported by in silico docking analyses, confirmed that RelA and Nrf2 both occupy multiple positions within the cxcl13 promoter. Collectively, in RelA high conditions, low Nrf2 and lack of cxcr5 promoter DNA-methylation govern CXCL13-CXCR5 co-expression within breast tumors, and thus drive disease progression and metastasis.

B cell and B cell-related pathways for novel cancer treatments.

B cells are recognized as the main effector cells of humoral immunity which suppress tumor progression by secreting immunoglobulins, promoting T cell response, and killing cancer cells directly. Given these properties, their anti-tumor immune response in the tumor micro-environment (TME) is of great interest. Although T cell-related immune responses have become a therapeutic target with the introduction of immune checkpoint inhibitors, not all patients benefit from these treatments. B cell and B cell-related pathways (CCL19, -21/CCR7 axis and CXCL13/CXCR5 axis) play key roles in activating immune response through humoral immunity and local immune activation via tertiary lymphoid structure (TLS) formation. However they have some protumorigenic works in the TME. Thus, a better understanding of B cell and B cell-related pathways is necessary to develop effective cancer control. In this review, we summarize recent evidences regarding the roles of B cell and B cell-related pathways in the TME and immune response and discuss their potential roles for novel cancer treatment strategies.

Histidine decarboxylase (HDC)-expressing granulocytic myeloid cells induce and recruit Foxp3+ regulatory T cells in murine colon cancer.

The colorectal tumor microenvironment contains a diverse population of myeloid cells that are recruited and converted to immunosuppressive cells, thus facilitating tumor escape from immunoediting. We have identified a genetically and functionally distinct subset of dynamic bone marrow myeloid cells that are characterized by histidine decarboxylase (HDC) expression. Lineage tracing in Hdc-CreERT2;R26-LSL-tdTomato mice revealed that in homeostasis, there is a strong bias by HDC+ myeloid cells toward the CD11b+Ly6Ghi granulocytic lineage, which was accelerated during azoxymethane/dextran sodium sulfate (AOM/DSS)-induced colonic carcinogenesis. More importantly, HDC+ myeloid cells strongly promoted colonic tumorigenesis, and colon tumor progression was profoundly suppressed by diphtheria toxin A (DTA)-mediated depletion of HDC+ granulocytic myeloid cells. In addition, tumor infiltration by Foxp3+ regulatory T cells (Tregs) was markedly impaired following HDC+ myeloid cell depletion. We identified an HDC+ myeloid-derived Cxcl13/Cxcr5 axis that mediated Foxp3 expression and Treg proliferation. Ablation of HDC+ myeloid cells or disruption of the Cxcl13/Cxcr5 axis by gene knockdown impaired the production and recruitment of Tregs. Cxcl13 induction of Foxp3 expression in Tregs during tumorigenesis was associated with Stat3 phosphorylation. Overall, HDC+ granulocytic myeloid cells affect CD8+ T cells directly and indirectly through the modulation of Tregs and thus appear to play key roles in suppressing tumoricidal immunity.

Novel CXCL13 transgenic mouse: inflammation drives pathogenic effect of CXCL13 in experimental myasthenia gravis.

Abnormal overexpression of CXCL13 is observed in many inflamed tissues and in particular in autoimmune diseases. Myasthenia gravis (MG) is a neuromuscular disease mainly mediated by anti-acetylcholine receptor autoantibodies. Thymic hyperplasia characterized by ectopic germinal centers (GCs) is a common feature in MG and is correlated with high levels of anti-AChR antibodies. We previously showed that the B-cell chemoattractant, CXCL13 is overexpressed by thymic epithelial cells in MG patients. We hypothesized that abnormal CXCL13 expression by the thymic epithelium triggered B-cell recruitment in MG. We therefore created a novel transgenic (Tg) mouse with a keratin 5 driven CXCL13 expression. The thymus of Tg mice overexpressed CXCL13 but did not trigger B-cell recruitment. However, in inflammatory conditions, induced by Poly(I:C), B cells strongly migrated to the thymus. Tg mice were also more susceptible to experimental autoimmune MG (EAMG) with stronger clinical signs, higher titers of anti-AChR antibodies, increased thymic B cells, and the development of germinal center-like structures. Consequently, this mouse model finally mimics the thymic pathology observed in human MG. Our data also demonstrated that inflammation is mandatory to reveal CXCL13 ability to recruit B cells and to induce tertiary lymphoid organ development.