In recent years, many immunoregulatory functions have been ascribed to soluble HLA-G (sHLA-G). Since chemotaxis is crucial for an efficient immune response, we have investigated for the first time ...the effects of sHLA-G on chemokine receptor expression and function in different human T cell populations.
T cell populations isolated from peripheral blood were stimulated in the presence or absence of sHLA-G. Chemokine receptors expression was evaluated by flow cytometry. sHLA-G downregulated expression of i) CCR2, CXCR3 and CXCR5 in CD4(+) T cells, ii) CXCR3 in CD8(+) T cells, iii) CXCR3 in Th1 clones iv) CXCR3 in TCR Vdelta2gamma9 T cells, and upregulated CXCR4 expression in TCR Vdelta2gamma9 T cells. sHLA-G inhibited in vitro chemotaxis of i) CD4(+) T cells towards CCL2, CCL8, CXCL10 and CXCL11, ii) CD8(+) T cells towards CXCL10 and CXCL11, iii) Th1 clones towards CXCL10, and iv) TCR Vdelta2gamma9 T cells towards CXCL10 and CXCL11. Downregulation of CXCR3 expression on CD4+ T cells by sHLA-G was partially reverted by adding a blocking antibody against ILT2/CD85j, a receptor for sHLA-G, suggesting that sHLA-G downregulated chemokine receptor expression mainly through the interaction with ILT2/CD85j. Follicular helper T cells (T(FH)) were isolated from human tonsils and stimulated as described above. sHLA-G impaired CXCR5 expression in T(FH) and chemotaxis of the latter cells towards CXCL13. Moreover, sHLA-G expression was detected in tonsils by immunohistochemistry, suggesting a role of sHLA-G in local control of T(FH) cell chemotaxis. Intracellular pathways were investigated by Western Blot analysis on total extracts from CD4+ T cells. Phosphorylation of Stat5, p70 s6k, beta-arrestin and SHP2 was modulated by sHLA-G treatment.
Our data demonstrated that sHLA-G impairs expression and functionality of different chemokine receptors in T cells. These findings delineate a novel mechanism whereby sHLA-G modulates T cell recruitment in physiological and pathological conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Review of the role of the CX3CL1/CX3CR1 axis in the regulation of normal B cells and malignant B cell microenvironment.
CX3CL1, or fractalkine, the unique member of the CX3C chemokine family, exists ...as a transmembrane glycoprotein, as well as in soluble form, each mediating different biological activities, and is constitutively expressed in many hematopoietic and nonhematopoietic tissues. CX3CR1, the CX3CL1 exclusive receptor, is a classical GPCR, expressed on NK cells, CD14+ monocytes, and some subpopulation of T cells, B cells, and mast cells. A recent paper by our group has demonstrated for the first time that highly purified human B cells from tonsil and peripheral blood expressed CX3CR1 at mRNA and protein levels. In particular, tonsil naïve, GC, and memory B cells expressed CX3CR1, but only GC centrocytes were attracted by soluble CX3CL1, which with its receptor, are also involved in the pathogenesis of several inflammatory disorders, as well as of cancer. Previous studies have shown that CX3CR1 is up‐regulated in different types of B cell lymphoma, as well as in B‐CLL. Recently, we have demonstrated that the CX3CL1/CX3CR1 axis is involved in the interaction of B‐CLL cells with their microenvironment. Taken together, our data delineate a novel role for the CX3CL1/CX3CR1 complex in the biology of normal B cells and B‐CLL cells. These topics are the subject of this review article.
C-X3-C motif chemokine ligand 1 (CX3CL1)/fractalkine is a chemokine released after cleavage by two metalloproteases, ADAM metallopeptidase domain 10 (ADAM10) and ADAM metallopeptidase domain 17 ...(ADAM17), involved in inflammation and angiogenesis in the cancer microenvironment. The role of the CX3CL1/ C-X3-C motif chemokine receptor 1(CX3CR1) axis in the multiple myeloma (MM) microenvironment is still unknown. Firstly, we analyzed bone marrow (BM) plasma levels of CX3CL1 in 111 patients with plasma cell disorders including 70 with active MM, 25 with smoldering myeloma (SMM), and 16 with monoclonal gammopathy of undetermined significance (MGUS). We found that BM CX3CL1 levels were significantly increased in MM patients compared to SMM and MGUS and correlated with BM microvessel density. Secondly, we explored the source of CX3CL1 in MM and BM microenvironment cells. Primary CD138⁺ cells did not express CXC3L1 but up-regulated its production by endothelial cells (ECs) through the involvement of tumor necrosis factor alpha (TNFα). Lastly, we demonstrated the presence of CX3CR1 on BM CD14⁺CD16⁺ monocytes of MM patients and on ECs, but not on MM cells. The role of CX3CL1 in MM-induced angiogenesis was finally demonstrated in both in vivo chick embryo chorioallantoic membrane and in vitro angiogenesis assays. Our data indicate that CX3CL1, present at a high level in the BM of MM patients, is a new player of the MM microenvironment involved in MM-induced angiogenesis.
The incidence of certain forms of tumors has increased progressively in recent years and is expected to continue growing as life expectancy continues to increase. Tumor-infiltrating NK cells may ...contribute to develop an anti-tumor response. Optimized combinations of different cancer therapies, including NK cell-based approaches for targeting tumor cells, have the potential to open new avenues in cancer immunotherapy. Functional inhibitory receptors on NK cells are needed to prevent their attack on healthy cells. Nevertheless, disruption of inhibitory receptors function on NK cells increases the cytotoxic capacity of NK cells against cancer cells. MicroRNAs (miRNAs) are small non-coding RNA molecules that target mRNA and thus regulate the expression of genes involved in the development, maturation, and effector functions of NK cells. Therapeutic strategies that target the regulatory effects of miRNAs have the potential to improve the efficiency of cancer immunotherapy. Interestingly, emerging evidence points out that some miRNAs can, directly and indirectly, control the surface expression of immune checkpoints on NK cells or that of their ligands on tumor cells. This suggests a possible use of miRNAs in the context of anti-tumor therapy. This review provides the current overview of the connections between miRNAs and regulation of NK cell functions and discusses the potential of these miRNAs as innovative biomarkers/targets for cancer immunotherapy.
Acute myeloid leukemia (AML) accounts for more than half of fatal cases in all pediatric leukemia patients; this observation highlights the need of more effective therapies. Thus, we investigated ...whether interleukin (IL)-27, an immunomodulatory cytokine, functions as an antitumor agent against pediatric AML cells.
Expression of WSX-1 and gp130 on AML cells from 16 pediatric patients was studied by flow cytometry. Modulation of leukemia cell proliferation or apoptosis upon IL-27 treatment in vitro was tested by bromodeoxyuridine/propidium iodide (PI) and Ki67, or Annexin V/PI staining and flow cytometric analysis. The angiogenic potential of AML cells treated or not with IL-27 was studied by chorioallantoic membrane assay and PCR array. In vivo studies were carried out using nonobese diabetic/severe combined immunodeficient (NOD/SCID)/Il2rg(-/-) mice injected intravenously with five pediatric AML cell samples. Leukemic cells engrafted in PBS and IL-27-treated animals were studied by immunohistochemical/morphologic analysis and by PCR array for expression angiogenic/dissemination-related genes.
We provided the first demonstration that (i) AML cells injected into NOD/SCID/Il2rg(-/-) mice gave rise to leukemia dissemination that was severely hampered by IL-27, (ii) compared with controls, leukemia cells harvested from IL-27-treated mice showed significant reduction of their angiogenic and spreading related genes, and (iii) similarly to what was observed in vivo, IL-27 reduced in vitro AML cell proliferation and modulated the expression of different genes involved in the angiogenic/spreading process.
These results provide an experimental rationale for the development of future clinical trials aimed at evaluating the toxicity and efficacy of IL-27.
Background: The antibody response to coronavirus disease 2019 (COVID-19) vaccination in patients with inflammatory bowel disease (IBD) on biological drugs is still unclear. Aim: To determine the ...anti-SARS-CoV-2 spike 1 (anti-S1-IgG) response rate and antibody levels following a complete COVID-19 vaccination cycle in patients with IBD on biological treatment. Methods: We assessed antibody response to COVID-19 in consecutive patients with IBD on biological drugs and without prior exposure to COVID-19. Sera were prospectively collected at baseline and at 21 days (T1), 42 days (T2), and 3 months (T3) after the first vaccine dose. Results: Among the 42 patients included in the study, the overall response rate at T3 was 97.6%, with no difference across the various biological drugs. After the first dose (T1), the response rate was higher in patients receiving anti-tumour necrosis factor (TNF) compared to patients treated with other biologics (p = 0.031). Among the responders, the anti-S1 levels were not significantly different among the various biological drugs at all study timepoints. Concomitant corticosteroids and disease activity had no impact on the response rate at all study timepoints. No unexpected side events were observed. Discussion: The antibody response to vaccination against COVID-19 in patients with IBD on biological drugs is optimal, independently of their mechanism of action. Patients treated with anti-TNF seem to have an earlier response to vaccination, while concomitant low-dose corticosteroids and disease activity does not seem to impact response. This information can be used to program vaccination and inform patients.
Interleukin (IL)-25, a member of the IL-17 cytokine superfamily, is produced by immune and non-immune cells and exerts type 2 pro-inflammatory effects in vitro and in vivo. The IL-25 receptor(R) is ...composed of the IL-17RA/IL-17RB subunits. Previous work showed that germinal centre (GC)-derived B-cell non Hodgkin lymphomas (B-NHL) expressed IL-17AR, formed by IL-17RA and IL-17RC subunits, and IL-17A/IL-17AR axis promoted B-NHL growth by stimulating neoangiogenesis. Here, we have investigated expression and function of IL-25/IL-25R axis in lymph nodes from human GC-derived B-NHL, i.e. Follicular Lymphoma (FL,10 cases), Diffuse Large B Cell Lymphoma (6 cases) and Burkitt Lymphoma (3 cases). Tumor cells expressed IL-25R and IL-25 that was detected also in non-malignant cells by flow cytometry. Immunohistochemical studies confirmed expression of IL-25R and IL-25 in FL cells, and highlighted IL-25 expression in bystander elements of the FL microenvironment. IL-25 i) up-regulated phosphorylation of NFkBp65, STAT-1 and JNK in B-NHL cells; ii) inhibited in vitro proliferation of the latter cells; iii) exerted anti-tumor activity in two in vivo B-NHL models by dampening expression of pro-angiogenic molecules as VEGF-C, CXCL6 and ANGPT3.
In conclusion, IL-25, that is intrinsically pro-angiogenic, inhibits B-NHL growth by reprogramming the angiogenic phenotype of B-NHL cells.
Review of how IL‐31 is expressed in the microenvironment of tumors of hematopoietic origin, where it may support cancer growth.
IL‐31 is a recently identified cytokine with a well‐defined role in the ...pathogenesis of pruritus. IL‐31, whose production is induced by IL‐4 and IL‐33, binds a heterodimeric receptor (R) composed of the exclusive IL‐31RA chain and the shared oncostatin M R. Signaling through the IL‐31R involves the MAPK, PI3K/AKT and Jak/STAT pathways. Different variants and isoforms of IL‐31RA with different signaling activities have been identified. IL‐31 is produced predominantly by circulating Th2 lymphocytes and skin‐homing CLA+CD45RO+ T cells. Studies in humans have demonstrated a pathogenic role for IL‐31 in atopic dermatitis and allergic asthma. The first demonstration of the involvement of the IL‐31/IL‐31R axis in cancer came from studies in patients with mycosis fungoides/Sézary syndrome, the most frequent, cutaneous T cell lymphoma. Tumor cells were shown to produce IL‐31, whose serum levels correlated with pruritus intensity. Follicular lymphoma (FL) B cells and their counterparts—germinal center B cells—produced IL‐31 and expressed IL‐31R, which signaled in the former, but not the latter, cells. IL‐31 released in association with microvesicles promoted tumor growth through autocrine/paracrine loops. Malignant mast cells from patients with mastocytosis or Philadelphia‐negative myeloproliferative disorder produced IL‐31, which contributed to pruritus pathogenesis. Finally, patients with endometrial carcinoma displayed high serum levels of IL‐31 and IL‐33, which may represent promising disease biomarkers. Targeting strategies for the IL‐31/IL‐31R axis have been developed, including the CIMM331 humanized anti‐human IL‐31RA antibody recently tested in a phase I/Ib study.
Soluble HLA-G (sHLA-G) inhibits natural killer (NK) cell functions. Here, we investigated sHLA-G–mediated modulation of (1) chemokine receptor and NK receptor expression and function and (2) cytokine ...and chemokine secretion in CD56bright and CD56dim NK cells. sHLA-G-treated or untreated peripheral blood (PB) and tonsil NK cells were analyzed for chemokine receptor and NK receptor expression by flow cytometry. sHLA-G down-modulated (1) CXCR3 on PB and tonsil CD56bright and CD56dim, (2) CCR2 on PB and tonsil CD56bright, (3) CX3CR1 on PB CD56dim, (4) CXCR5 on tonsil CD56dim, and (5) CD94/NKG2A on PB and tonsil CD56bright and CD56dim NK cells. Such sHLA-G–mediated down-modulations were reverted by adding anti–HLA-G or anti–ILT2 mAbs. sHLA-G inhibited chemotaxis of (1) PB NK cells toward CXCL10, CXCL11, and CX3CL1 and (2) PB CD56bright NK cells toward CCL2 and CXCL10. IFN-γ secretion induced by NKp46 engagement was inhibited by NKG2A engagement in untreated but not in sHLA-G–treated NK cells. sHLA-G up-regulated secretion of (1) CCL22 in CD56bright and CD56dim and (2) CCL2, CCL8, and CXCL2-CXCL3 in CD56dim PB NK cells. Signal transduction experiments showed sHLA-G–mediated down-modulation of Stat5 phosphorylation in PB NK cells. In conclusion, our data delineated novel mechanisms of sHLA-G–mediated inhibition of NK-cell functions.
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