Specific Targeting of STAT3 in B Cells Suppresses Progression of B Cell Lymphoma.

The signal transducer and activator of transcription 3 (STAT3), which regulates multiple oncogenic processes, has been found to be constitutively activated in lymphoma, suggesting its potential as a therapeutic target. Here, we constructed an anti-CD19-N-(4-carboxycyclohexylmethyl) maleimide N-hydroxysuccinimide ester (SMCC)-protamine (CSP)-STAT3 small interfering RNA (siRNA) conjugate and demonstrated that the CSP-STAT3 siRNA conjugate could specifically bind to normal B cells and A20 lymphoma cells in vitro. It decreased the STAT3 expression in B cell lymphoma cell lines (A20, SU-DHL-2 and OCI-Ly3), resulting in reduced proliferation of lymphoma cells featured with lower S-phase and higher apoptosis. Using an A20 transplantable lymphoma model, we found that the CSP-STAT3 siRNA conjugate significantly inhibited tumor growth and weight. Ki-67, p-STAT3, STAT3, and serum IL-6 levels were all significantly reduced in A20-bearing mice treated with CSP-STAT3 siRNA. These findings indicate that specifically targeting STAT3 siRNA to B cell lymphoma cell lines can significantly decrease STAT3 activity and inhibit tumor progression in vitro and in vivo, suggesting its potential utilization for cancer treatment.

Natural γδT17 cell development and functional acquisition is governed by the mTORC2-c-Maf-controlled mitochondrial fission pathway.

Natural IL-17-producing γδ T cells (γδT17 cells) are unconventional innate-like T cells that undergo functional programming in the fetal thymus. However, the intrinsic metabolic mechanisms of γδT17 cell development remain undefined. Here, we demonstrate that mTORC2, not mTORC1, selectively controls the functional fate commitment of γδT17 cells through regulating transcription factor c-Maf expression. scRNA-seq data suggest that fetal and adult γδT17 cells predominately utilize mitochondrial metabolism. mTORC2 deficiency results in impaired Drp1-mediated mitochondrial fission and mitochondrial dysfunction characterized by mitochondrial membrane potential (ΔΨm) loss, reduced oxidative phosphorylation (OXPHOS), and subsequent ATP depletion. Treatment with the Drp1 inhibitor Mdivi-1 alleviates imiquimod-induced skin inflammation. Reconstitution of intracellular ATP levels by ATP-encapsulated liposome completely rescues γδT17 defect caused by mTORC2 deficiency, revealing the fundamental role of metabolite ATP in γδT17 development. These results provide an in-depth insight into the intrinsic link between the mitochondrial OXPHOS pathway and γδT17 thymic programming and functional acquisition.

Irreversible electroporation augments ß-glucan induced trained innate immunity for the treatment of pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic cancer (PC) is a challenging diagnosis that is yet to benefit from the advancements in immuno-oncologic treatments. Irreversible electroporation (IRE), a non-thermal method of tumor ablation, is used in treatment of select patients with locally-advanced unresectable PC and has potentiated the effect of certain immunotherapies. Yeast-derived particulate ß-glucan induces trained innate immunity and successfully reduces murine PC tumor burden. This study tests the hypothesis that IRE may augment ß-glucan induced trained immunity in the treatment of PC. METHODS: ß-Glucan-trained pancreatic myeloid cells were evaluated ex vivo for trained responses and antitumor function after exposure to ablated and unablated tumor-conditioned media. ß-Glucan and IRE combination therapy was tested in an orthotopic murine PC model in wild-type and Rag-/- mice. Tumor immune phenotypes were assessed by flow cytometry. Effect of oral ß-glucan in the murine pancreas was evaluated and used in combination with IRE to treat PC. The peripheral blood of patients with PC taking oral ß-glucan after IRE was evaluated by mass cytometry. RESULTS: IRE-ablated tumor cells elicited a potent trained response ex vivo and augmented antitumor functionality. In vivo, ß-glucan in combination with IRE reduced local and distant tumor burden prolonging survival in a murine orthotopic PC model. This combination augmented immune cell infiltration to the PC tumor microenvironment and potentiated the trained response from tumor-infiltrating myeloid cells. The antitumor effect of this dual therapy occurred independent of the adaptive immune response. Further, orally administered ß-glucan was identified as an alternative route to induce trained immunity in the murine pancreas and prolonged PC survival in combination with IRE. ß-Glucan in vitro treatment also induced trained immunity in peripheral blood monocytes obtained from patients with treatment-naïve PC. Finally, orally administered ß-glucan was found to significantly alter the innate cell landscape within the peripheral blood of five patients with stage III locally-advanced PC who had undergone IRE. CONCLUSIONS: These data highlight a relevant and novel application of trained immunity within the setting of surgical ablation that may stand to benefit patients with PC.

A Tumor-admixture Model to Interrogate Immune Cell-dependent Tumorigenesis.

A rigorous determination of effector contributions of tumor-infiltrating immune cells is critical for identifying targetable molecular mechanisms for the development of novel cancer immunotherapies. A tumor/immune cell-admixture model is an advantageous strategy to study tumor immunology as the fundamental methodology is relatively straightforward, while also being adaptable to scale to address increasingly complex research queries. Ultimately, this method can provide robust experimental information to complement more traditional murine models of tumor immunology. Here, we describe a tumor/macrophage-admixture model using bone marrow-derived macrophages to investigate macrophage-dependent tumorigenesis. Additionally, we provide commentary on potential branch points for optimization with other immune cells, experimental techniques, and cancer types.

Reactive myelopoiesis and FX-expressing macrophages triggered by chemotherapy promote cancer lung metastasis.

Several preclinical studies have demonstrated that certain cytotoxic drugs enhance metastasis, but the importance of host responses triggered by chemotherapy in regulating cancer metastasis has not been fully explored. Here, we showed that multidose gemcitabine (GEM) treatment promoted breast cancer lung metastasis in a transgenic spontaneous breast cancer model. GEM treatment significantly increased accumulation of CCR2+ macrophages and monocytes in the lungs of tumor-bearing as well as tumor-free mice. These changes were largely caused by chemotherapy-induced reactive myelopoiesis biased toward monocyte development. Mechanistically, enhanced production of mitochondrial ROS was observed in GEM-treated BM Lin-Sca1+c-Kit+ cells and monocytes. Treatment with the mitochondria targeted antioxidant abrogated GEM-induced hyperdifferentiation of BM progenitors. In addition, GEM treatment induced upregulation of host cell-derived CCL2, and knockout of CCR2 signaling abrogated the pro-metastatic host response induced by chemotherapy. Furthermore, chemotherapy treatment resulted in the upregulation of coagulation factor X (FX) in lung interstitial macrophages. Targeting activated FX (FXa) using FXa inhibitor or F10 gene knockdown reduced the pro-metastatic effect of chemotherapy. Together, these studies suggest a potentially novel mechanism for chemotherapy-induced metastasis via the host response-induced accumulation of monocytes/macrophages and interplay between coagulation and inflammation in the lungs.

Inducing trained immunity in pro-metastatic macrophages to control tumor metastasis.

Metastasis is the leading cause of cancer-related deaths and myeloid cells are critical in the metastatic microenvironment. Here, we explore the implications of reprogramming pre-metastatic niche myeloid cells by inducing trained immunity with whole beta-glucan particle (WGP). WGP-trained macrophages had increased responsiveness not only to lipopolysaccharide but also to tumor-derived factors. WGP in vivo treatment led to a trained immunity phenotype in lung interstitial macrophages, resulting in inhibition of tumor metastasis and survival prolongation in multiple mouse models of metastasis. WGP-induced trained immunity is mediated by the metabolite sphingosine-1-phosphate. Adoptive transfer of WGP-trained bone marrow-derived macrophages reduced tumor lung metastasis. Blockade of sphingosine-1-phosphate synthesis and mitochondrial fission abrogated WGP-induced trained immunity and its inhibition of lung metastases. WGP also induced trained immunity in human monocytes, resulting in antitumor activity. Our study identifies the metabolic sphingolipid-mitochondrial fission pathway for WGP-induced trained immunity and control over metastasis.

Dynamic trafficking patterns of IL-17-producing γδ T cells are linked to the recurrence of skin inflammation in psoriasis-like dermatitis.

BACKGROUND: Psoriasis recurrence is a clinically challenging issue. However, the underlying mechanisms haven't been fully understood. METHODS: RNAseq analysis from affected skin of psoriatic patients treated with topical glucocorticoid (GC) with different outcomes was performed. In addition, imiquimod (IMQ)-induced mouse psoriasis-like model was used to mimic GC treatment in human psoriasis patients. Skin tissues and draining and distant lymph nodes (LNs) were harvested for flow cytometry and histology analyses. FINDINGS: RNAseq analysis revealed that chemokine and chemokine receptor gene expression was decreased in post-treated skin compared to pre-treated samples but was subsequently increased in the recurred skin. In IMQ-induced mouse psoriasis-like model, we found that γδT17 cells were decreased in the skin upon topical GC treatment but surprisingly increased in the draining and distant LNs. This redistribution pattern lasted even two weeks post GC withdrawal. Upon IMQ re-challenge on the same site, mice previously treated with GC developed more severe skin inflammation. There were γδT17 cells migrated from LNs to the skin. This dynamic trafficking was dependent on CCR6 as this phenomenon was completely abrogated in CCR6-deficient mice. In addition, inhibition of lymphocyte egress prevented this heightened skin inflammation induced by IMQ rechallenge. INTERPRETATION: Redistribution of pathogenic γδT17 cells may be vital to prevent disease recurrence and this model of psoriasis-like dermatitis. FUNDING: This work was supported by National Natural Science Foundation of China 81830095/H1103, 81761128008/H10 (J.Z.) and the NIH R01AI128818 and the National Psoriasis Foundation (J.Y.).

Differential metabolic requirement governed by transcription factor c-Maf dictates innate γδT17 effector functionality in mice and humans.

Cellular metabolism has been proposed to govern distinct γδ T cell effector functions, but the underlying molecular mechanisms remain unclear. We show that interleukin-17 (IL-17)-producing γδ T (γδT17) and interferon-γ (IFN-γ)-producing γδ T (γδT1) cells have differential metabolic requirements and that the rate-limiting enzyme isocitrate dehydrogenase 2 (IDH2) acts as a metabolic checkpoint for their effector functions. Intriguingly, the transcription factor c-Maf regulates γδT17 effector function through direct regulation of IDH2 promoter activity. Moreover, mTORC2 affects the expression of c-Maf and IDH2 and subsequent IL-17 production in γδ T cells. Deletion of c-Maf in γδ T cells reduces metastatic lung cancer development, suggesting c-Maf as a potential target for cancer immune therapy. We show that c-Maf also controls IL-17 production in human γδ T cells from peripheral blood and in oral cancers. These results demonstrate a critical role of the transcription factor c-Maf in regulating γδT17 effector function through IDH2-mediated metabolic reprogramming.

The induction of peripheral trained immunity in the pancreas incites anti-tumor activity to control pancreatic cancer progression.

Despite the remarkable success of immunotherapy in many types of cancer, pancreatic ductal adenocarcinoma has yet to benefit. Innate immune cells are critical to anti-tumor immunosurveillance and recent studies have revealed that these populations possess a form of memory, termed trained innate immunity, which occurs through transcriptomic, epigenetic, and metabolic reprograming. Here we demonstrate that yeast-derived particulate ß-glucan, an inducer of trained immunity, traffics to the pancreas, which causes a CCR2-dependent influx of monocytes/macrophages to the pancreas that display features of trained immunity. These cells can be activated upon exposure to tumor cells and tumor-derived factors, and show enhanced cytotoxicity against pancreatic tumor cells. In orthotopic models of pancreatic ductal adenocarcinoma, ß-glucan treated mice show significantly reduced tumor burden and prolonged survival, which is further enhanced when combined with immunotherapy. These findings characterize the dynamic mechanisms and localization of peripheral trained immunity and identify an application of trained immunity to cancer.

Immobile ligands enhance FcγR-TLR2/1 crosstalk by promoting interface overlap of receptor clusters.

Innate immune cells detect pathogens through simultaneous stimulation of multiple receptors, but how cells use the receptor crosstalk to elicit context-appropriate responses is unclear. Here, we reveal that the inflammatory response of macrophages from FcγR-TLR2/1 crosstalk inversely depends on the ligand mobility within a model pathogen membrane. The mechanism is that FcγR and TLR2/1 form separate nanoclusters that interact at their interfaces during crosstalk. Less mobile ligands induce stronger interactions and more overlap between the receptor nanoclusters, leading to enhanced signaling. Different from the prevailing view that immune receptors colocalize to synergize their signaling, our results show that FcγR-TLR2/1 crosstalk occurs through interface interactions between non-colocalizing receptor nanoclusters, which are modulated by ligand mobility. This suggests a mechanism by which innate immune cells could use physical properties of ligands to fine-tune host responses.

Tumor-derived exosomes drive immunosuppressive macrophages in a pre-metastatic niche through glycolytic dominant metabolic reprogramming.

One of the defining characteristics of a pre-metastatic niche, a fundamental requirement for primary tumor metastasis, is infiltration of immunosuppressive macrophages. How these macrophages acquire their phenotype remains largely unexplored. Here, we demonstrate that tumor-derived exosomes (TDEs) polarize macrophages toward an immunosuppressive phenotype characterized by increased PD-L1 expression through NF-kB-dependent, glycolytic-dominant metabolic reprogramming. TDE signaling through TLR2 and NF-κB leads to increased glucose uptake. TDEs also stimulate elevated NOS2, which inhibits mitochondrial oxidative phosphorylation resulting in increased conversion of pyruvate to lactate. Lactate feeds back on NF-κB, further increasing PD-L1. Analysis of metastasis-negative lymph nodes of non-small-cell lung cancer patients revealed that macrophage PD-L1 positively correlates with levels of GLUT-1 and vesicle release gene YKT6 from primary tumors. Collectively, our study provides a novel mechanism by which macrophages within a pre-metastatic niche acquire their immunosuppressive phenotype and identifies an important link among exosomes, metabolism, and metastasis.

Integrin CD11b Negatively Regulates B Cell Receptor Signaling to Shape Humoral Response during Immunization and Autoimmunity.

Our previous work has revealed the ability of CD11b to regulate BCR signaling and control autoimmune disease in mice. However, how CD11b regulates the immune response under normal conditions remains unknown. Through the use of a CD11b knockout model on a nonautoimmune background, we demonstrated that CD11b-deficient mice have an elevated Ag-specific humoral response on immunization. Deletion of CD11b resulted in elevated low-affinity and high-affinity IgG Ab and increases in Ag-specific germinal center B cells and plasma cells (PCs). Examination of BCR signaling in CD11b-deficient mice revealed defects in association of negative regulators pLyn and CD22 with the BCR, but increases in colocalizations between positive regulator pSyk and BCR after stimulation. Using a CD11b-reporter mouse model, we identified multiple novel CD11b-expressing B cell subsets that are dynamically altered during immunization. Subsequent experiments using a cell-specific CD11b deletion model revealed this effect to be B cell intrinsic and not altered by myeloid cell CD11b expression. Importantly, CD11b expression on PCs also impacts on BCR repertoire selection and diversity in autoimmunity. These studies describe a novel role for CD11b in regulation of the healthy humoral response and autoimmunity, and reveal previously unknown populations of CD11b-expressing B cell subsets, suggesting a complex function for CD11b in B cells during development and activation.

A specific low-density neutrophil population correlates with hypercoagulation and disease severity in hospitalized COVID-19 patients.

SARS coronavirus 2 (SARS-CoV-2) is a novel viral pathogen that causes a clinical disease called coronavirus disease 2019 (COVID-19). Although most COVID-19 cases are asymptomatic or involve mild upper respiratory tract symptoms, a significant number of patients develop severe or critical disease. Patients with severe COVID-19 commonly present with viral pneumonia that may progress to life-threatening acute respiratory distress syndrome (ARDS). Patients with COVID-19 are also predisposed to venous and arterial thromboses that are associated with a poorer prognosis. The present study identified the emergence of a low-density inflammatory neutrophil (LDN) population expressing intermediate levels of CD16 (CD16Int) in patients with COVID-19. These cells demonstrated proinflammatory gene signatures, activated platelets, spontaneously formed neutrophil extracellular traps, and enhanced phagocytic capacity and cytokine production. Strikingly, CD16Int neutrophils were also the major immune cells within the bronchoalveolar lavage fluid, exhibiting increased CXCR3 but loss of CD44 and CD38 expression. The percentage of circulating CD16Int LDNs was associated with D-dimer, ferritin, and systemic IL-6 and TNF-α levels and changed over time with altered disease status. Our data suggest that the CD16Int LDN subset contributes to COVID-19-associated coagulopathy, systemic inflammation, and ARDS. The frequency of that LDN subset in the circulation could serve as an adjunct clinical marker to monitor disease status and progression.

Transcription factor c-Maf is a checkpoint that programs macrophages in lung cancer.

Macrophages have been linked to tumor initiation, progression, metastasis, and treatment resistance. However, the transcriptional regulation of macrophages driving the protumor function remains elusive. Here, we demonstrate that the transcription factor c-Maf is a critical controller for immunosuppressive macrophage polarization and function in cancer. c-Maf controls many M2-related genes and has direct binding sites within a conserved noncoding sequence of the Csf-1r gene and promotes M2-like macrophage-mediated T cell suppression and tumor progression. c-Maf also serves as a metabolic checkpoint regulating the TCA cycle and UDP-GlcNAc biosynthesis, thus promoting M2-like macrophage polarization and activation. Additionally, c-Maf is highly expressed in tumor-associated macrophages (TAMs) and regulates TAM immunosuppressive function. Deletion of c-Maf specifically in myeloid cells results in reduced tumor burden with enhanced antitumor T cell immunity. Inhibition of c-Maf partly overcomes resistance to anti-PD-1 therapy in a subcutaneous LLC tumor model. Similarly, c-Maf is expressed in human M2 and tumor-infiltrating macrophages/monocytes as well as circulating monocytes of human non-small cell lung carcinoma (NSCLC) patients and critically regulates their immunosuppressive activity. The natural compound ß-glucan downregulates c-Maf expression on macrophages, leading to enhanced antitumor immunity in mice. These findings establish a paradigm for immunosuppressive macrophage polarization and transcriptional regulation by c-Maf and suggest that c-Maf is a potential target for effective tumor immunotherapy.

Tumor Microenvironment following Gemcitabine Treatment Favors Differentiation of Immunosuppressive Ly6Chigh Myeloid Cells.

Regulation of myeloid-derived suppressor cells (MDSC) by ongoing inflammation following repeated chemotherapy remain elusive. In this study, we show that a multidose clinical regimen of gemcitabine (GEM) treatment enhances the immunosuppressive function of monocytic MDSC (M-MDSC), although tumor development is delayed in E0771 tumor-bearing mice. Accordingly, effector IFN-γ-producing CD4 and CD8 T cells are significantly decreased in the tumor microenvironment (TME) of GEM-treated mice. The conditioned medium of GEM-treated tumor cells enhances differentiation of mouse bone marrow cells and human PBMC into immunosuppressive M-MDSC. Cytokine profiling of GEM-treated tumor cells identifies GM-CSF as one of the most differentially expressed cytokines. Blockade or knockdown of GM-CSF can partially reduce immunosuppression of Ly6Chigh cells induced by GEM-conditioned medium. Knockdown of GM-CSF in tumor cells also delays tumor progression with decreased accumulation of M-MDSC in the TME. Mechanistically, enhanced production of reactive oxygen species and activation of NF-κB are observed in GEM-treated tumor cells. Treatment with the mitochondrial-targeted antioxidant and inhibitor of NF-κB signaling can abrogate GEM-induced hyperexpression of GM-CSF in E0771 cells. In addition, the phagocytic clearance of apoptotic tumor cells (efferocytosis) enhances the immunosuppressive function of bone marrow Ly6Chigh myeloid cells. Further, GEM treatment results in metabolic changes in residual tumor cells, leading to the resistance to T cell-mediated killing. Together, our results define an undesired effect of repeated GEM treatment promoting immunosuppression in TME via upregulation of GM-CSF and efferocytosis as well as deregulation of lipid metabolism in residual tumor cells.

Tumor Microenvironment Modulates Immunological Outcomes of Myeloid Cells with mTORC1 Disruption.

The role of the mTOR signaling pathway in different myeloid cell subsets is poorly understood in the context of tumor development. In this study, myeloid cell-specific Raptor knockout (KO) mice were used to determine the roles of mechanistic target of rapamycin complex 1 (mTORC1) in regulating macrophage function from Lewis lung carcinoma (LLC) s.c. tumors and lung tumor metastasis. We found no difference in tumor growth between conditional Raptor KO and control mice in the s.c. tumor models, although depletion of mTORC1 decreased the immunosuppressive function of tumor-associated macrophages (TAM). Despite the decreased immunosuppressive activity of TAM, M1-like TAM differentiation was impaired in the s.c. tumor microenvironment of mTORC1 conditional Raptor KO mice due to downregulated CD115 expression on macrophages. In addition, TNF-α production by mTORC1-deficient myeloid cells was also decreased in the s.c. LLC tumors. On the contrary, disruption of mTORC1 in myeloid cells promoted lung cancer metastasis. Accordingly, immunosuppressive interstitial macrophages/metastasis-associated macrophages (CD11b+F4/80high) were accumulated in the lungs of Raptor KO mice in the LLC lung metastasis model, leading to decreased Th1 responses. Taken together, our results demonstrate that differential tumor microenvironment dictates the immunological outcomes of myeloid cells, with mTORC1 disruption leading to different tumor growth phenotypes.

Transcription Factor STAT3 Serves as a Negative Regulator Controlling IgE Class Switching in Mice.

A mutation in STAT3 has been linked to the incidence of autosomal dominant hyper IgE syndrome, a disease characterized by elevated serum IgE Ab. However, how this genetic mutation leads to the phenotype has not been fully understood. We investigated the specific role of STAT3 in the germinal center (GC) B cells and plasma cells for IgE class switching. Through the use of STAT3 conditional knockout (cKO) mice in a Th2-type immunization model, we demonstrated that CD2-Cre-driven STAT3 cKO mice showed elevated IgE and decreased IgG1 in the serum and a reduction in GC formation. Within the GC, IgG1 + GC B cells were decreased, whereas IgE+ GC B cells were more prevalent. Additionally, these mice exhibited reduced IgG1 and elevated IgE populations of Ab-producing plasma cells. Subsequent experiments using a CD19-Cre cKO mouse established this effect to be B cell-intrinsic. Transcription factors critical for GC and plasma cell differentiation, including Bcl-6 and Aicda, were shown to function as downstream signals of STAT3 regulation. Chromatin immunoprecipitation sequencing analysis revealed that many genes, including Bcl3 and Crtc2, were among the direct STAT3 regulated targets. Mice with STAT3 deficiency in B cells also demonstrated an increase in lung inflammation when used in an asthma-like disease model. This model suggests a negative role for STAT3 in regulating class switching of the GC B cells from the IgG1 to the IgE producing state, which may serve as a therapeutic target for treatment of autosomal dominant hyper IgE syndrome and other immune disorders.

Innate γδT17 cells play a protective role in DSS-induced colitis via recruitment of Gr-1+CD11b+ myeloid suppressor cells.

Innate γδ T cells play critical roles in mucosal immunity such as regulating intestinal epithelial homeostasis. In addition, γδ T cells are significantly increased in the inflamed mucosa of patients with ulcerative colitis. However, γδ T cells are a heterogeneous population. IL-17-producing versus IFNγ-producing γδ T cells play differential roles in different disease settings. Therefore, dissecting the exact role of different subsets of γδ T cells in colitis is essential for understanding colitis immunopathogenesis. In the current study, we found that TCR δ-deficient mice had a more severe dextran sodium sulfate (DSS)-induced colitis that was reduced upon reconstitution of γδT17 cells but not IFNγ-producing γδ T cells. Immunophenotyping of the cellular infiltrate upon DSS-induced colitis showed a reduced infiltration of Gr-1+CD11b+ myeloid cells into the sites of inflammation in mice lacking γδT17 cells. Further experiments demonstrated that IL-17, IL-18, and chemokine CXCL5 were critical in Gr-1+CD11b+ myeloid cell recruitment. In vitro T cell suppressive assay indicated that this Gr-1+CD11b+ population was immunosuppressive. Depletion of Gr-1+CD11b+ myeloid cells resulted in an increase severity of DSS-induced colitis. Our study elucidates a new immune pathway involving γδT17-dependent recruitment of Gr-1+CD11b+ myeloid cells to the site of colitis inflammation important in the protection of colitis initiation and progression.

Polysaccharides from Epimedium koreanum Nakai with immunomodulatory activity and inhibitory effect on tumor growth in LLC-bearing mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Epimedium koreanum Nakai is documented as tonic herbal in China for over a thousand years and has the potential to enhance the body's immunity according to the theory of traditional Chinese medicine. Polysaccharides are one of the most important effective compounds in Epimedium koreanum Nakai. Accumulating evidence indicated polysaccharides derived from traditional Chinese medicine have potent immune-enhancing properties and relatively nontoxic effects in cancer treatment. However, information about immunological regulation in tumor of Epimedium koreanum Nakai polysaccharides is limited and the reports of purification, characterization of polysaccharides have remained less. The purpose of our study was to further investigate the active polysaccharides from Epimedium koreanum Nakai by evaluating the immune-regulation activities in tumor-bearing mice and provide reasonable explanation for traditional application. MATERIALS AND METHODS: We firstly purified Epimedium koreanum polysaccharide (EPS) from crude extracts and evaluated EPS in vitro using immunological experiments including maturation and Ag presentation function of DCs, CD4 T-cell differentiation and secretion of anti-cancer cytokines. In LLC-bearing mice model, we investigated its antitumor activities through evaluation of tumor cell proliferative activity, calculation of immune organ indexes and relative host immune system function tests. RESULTS: Results showed that EPS (180 × 104Da) was composed of mannose (Man), rhamnose (Rha), glucuronic acid (GlcUA), galactosamine (GalN), glucose (Glc), galactose (Gal), arabinose (Ara) and fructose (Fuc). Chemical composition assay indicated EPS was a fraction with 28.20% uronic acid content. FT-IR suggested the presence of pyraoid ring in EPS and SEM displayed smooth surface embedded by several pores. Moreover, Our study suggested EPS could remarkably stimulate macrophages to secrete substantial anti-cancer cytokines and promote maturation as well as Ag presentation function of DCs. Strikingly, CD4 T-cell differentiation and increased INF-γ production stimulated by EPS-activated macrophages were observed in the research. Furthermore, EPS exhibited prominent antitumor activities through regulating host immune system function in LLC-bearing mice. Taken together, experimental findings suggested EPS could be regarded as a potential immune-stimulating modifier for cancer therapy. CONCLUSION: Our studies demonstrated the polysaccharide (180 × 104Da) purified from Epimedium koreanum Nakai could promote maturation and Ag presentation function of DCs, increase the level of immunomodulatory cytokines and activate CD4 T-cell differentiation. Furthermore, it may inhibit the tumor growth in LLC-bearing mice through regulating host immune system function.

STAT3 Signaling in B Cells Is Critical for Germinal Center Maintenance and Contributes to the Pathogenesis of Murine Models of Lupus.

Ab maturation as well as memory B and plasma cell differentiation occur primarily in the germinal centers (GCs). Systemic lupus erythematosus (SLE) may develop as a result of enhanced GC activity. Previous studies have shown that the dysregulated STAT3 pathway is linked to lupus pathogenesis. However, the exact role of STAT3 in regulating SLE disease progression has not been fully understood. In this study, we demonstrated that STAT3 signaling in B cells is essential for GC formation and maintenance as well as Ab response. Increased cell apoptosis and downregulated Bcl-xL and Mcl-1 antiapoptotic gene expression were found in STAT3-deficient GC B cells. The follicular helper T cell response positively correlated with GC B cells and was significantly decreased in immunized B cell STAT3-deficient mice. STAT3 deficiency also led to the defect of plasma cell differentiation. Furthermore, STAT3 deficiency in autoreactive B cells resulted in decreased autoantibody production. Results obtained from B cell STAT3-deficient B6.MRL/lpr mice suggest that STAT3 signaling significantly contributes to SLE pathogenesis by regulation of GC reactivity, autoantibody production, and kidney pathology. Our findings provide new insights into the role of STAT3 signaling in the maintenance of GC formation and GC B cell differentiation and identify STAT3 as a novel target for treatment of SLE.