T lymphocyte adhesion to the fibronectin and laminin components of the extracellular matrix is regulated by the CD4 molecule

The Matrisome Is Associated with Metabolic Reprograming in Stem-like Phenotypes of Gastric Cancer

Simple Summary

Our results suggested a correlation between the metabolic reprogramming associated with the high-matrisome group and stem-like phenotype in gastric cancer. Carbohydrate sulfotransferase 7 was found to be associated with the signaling transduction of overexpressed oncogenes and tumor suppressor genes in the high-matrisome group. The high expression of glycosaminoglycan biosynthesis-chondroitin sulfate metabolic pathway genes was associated with poor prognosis.

Abstract

The extracellular matrix (ECM) is an important regulator of all cellular functions, and the matrisome represents a major component of the tumor microenvironment. The matrisome is an essential component comprising genes encoding ECM glycoproteins, collagens, and proteoglycans; however, its role in cancer progression and the development of stem-like molecular subtypes in gastric cancer is unknown. We analyzed gastric cancer data from five molecular subtypes (n = 497) and found that metabolic reprograming differs based on the state of the matrisome. Approximately 95% of stem-like cancer type samples of gastric cancer were in the high-matrisome category, and energy metabolism was considerably increased in the high-matrisome group. Particularly, high glycosaminoglycan biosynthesis-chondroitin sulfate metabolic reprograming was associated with an unfavorable prognosis. Glycosaminoglycan biosynthesis-chondroitin sulfate metabolic reprograming may occur according to the matrisome status and contribute to the development of stem-like phenotypes. Our analysis suggests the possibility of precision medicine for anticancer therapies.

Preferential locomotion of leukemic cells towards laminin isoforms 8 and 10

To identify the laminin isoforms of the basement membranes that could be implicated in the extravasation process of neoplastic lymphocytes, a number of purified laminins and one native renal laminin complex were comparatively investigated for their ability to promote migration of neoplastic lymphocytes in vitro. The identity/composition of a human placental laminin complex was asserted by combining immunochemical assays, sequence determination of tryptic peptides, and ultrastructural analysis to be composed predominantly of laminin-10 in which the coiled-coil C-terminal regions and the G globular domain of the alpha5 chain were preserved intact despite the enzymatic treatment used for its isolation. Lymphoma and leukemic cell lines failed to migrate towards laminin-4, -9, -11, moved poorly in response to laminin-1, -2/4, -5 and the renal laminin complex, but markedly locomoted towards the subendothelial laminin-8 and -10. The motility-promoting interaction with these latter laminins was interchangeably mediated by the alpha3beta1 and alpha6beta1 integrins. Lymphocyte locomotion on laminins assayed in the presence of cytokines was either reduced or enhanced suggesting that local cytokine milieu could further influence motility response.

Quantitative study of beta1-integrin expression and fibronectin interaction profile of T lymphocytes in vitro infected with HIV

Cell-extracellular matrix interactions, regulated in part by beta1-integrins, play a key role in the recirculation of T lymphocytes and tissue infiltration in inflammatory and immune responses. HIV infection may affect CD4+ T cell adhesion, and the trafficking and migration of these cells, which are crucial for foreign antigen recognition. We investigated this by studying the expression of the beta1-integrin chains CD29 and CD49c, -d, -e, and -f, on in vitro HIV-infected primary T cells. We also assessed fibronectin binding and production by CD4+ lymphocytes. X4 (HIV-1/LAI), R5 (HIV-1/Ba-L), and X4R5 (HIV-2/ROD) strains, and X4R5 primary isolates (HIV-1/DAS, HIV-1/THI), with different cytopathogenicity and replication kinetics, were used. Beta1-integrin expression on CD4+ and CD4- T cell subpopulations was regulated by cell activation with phytohemagglutinin-P and interleukin 2, but was unaffected by HIV infection, even at the peak of viral replication and CD4+ cell depletion. Similarly, fibronectin binding to CD4+ lymphocytes was not affected by HIV infection. This suggests that infected lymphocytes may be able to extravasate, migrate, and recirculate within the body until their death.

Evidence of integrity of the follicular basement membrane in Hashimoto's thyroiditis

The basement membrane as an antigenic structure in autoimmune diseases has been a matter of controversy. The purpose of our study was to determine possible structural changes in the follicular basement membrane (FBM) in thyroid autoimmune and non-autoimmune diseases. Immunohistochemical staining for collagen IV and laminin showed that the continuity of the FBM was preserved in toxic adenoma (three cases), atoxic multinodular goiter (nine cases) as well as in autoimmune disease. Integrity of the FBM was observed in all 11 cases of Graves' disease and Hashimoto's thyroiditis (seven cases) studied. In some instances, the FBM was thinned in areas of contact with inflammatory infiltrate. We conclude that the auto-antibodies, and possibly other factors present in autoimmune thyroid diseases, do not significantly alter the integrity of the FBM.

Cell migration strategies in 3-D extracellular matrix: differences in morphology, cell matrix interactions, and integrin function

Cell migration in extracellular matrix is a complex process of adhesion and deadhesion events combined with cellular strategies to overcome the biophysical resistance imposed by three-dimensionally interconnected matrix ligands. Using a 3-D collagen matrix migration model in combination with computer-assisted cell tracking for reconstruction of migration paths and confocal microscopy, we investigated molecular principles governing cell-matrix interactions and migration of different cell types. Highly invasive MV3 melanoma cells and fibroblasts are large and highly polarized cells migrating at low speed (0.1-0.5 microm/min) and at high directional persistence. MV3 melanoma cells utilize adhesive migration strategies as characterized by high beta1 integrin surface expression, beta1 integrin clustering at interactions with matrix fibers, and beta1 integrin-mediated adhesion for force generation and migration. In contrast, T lymphocytes and dendritic cells are highly mobile cells of lower beta1 integrin expression migrating at 10- to 40-fold higher velocities, and directionally unpredictable path profiles. This migration occurs in the absence of focal adhesions and largely independent of beta1 integrin-mediated adhesion. Whereas cell-matrix interactions of migrating tumor cells result in traction and reorientation of collagen fibers, partial matrix degradation, and pore formation, leukocytes form transient and short-lived interactions with the collagen lacking structural proteolysis and matrix remodeling. In conclusion, the 3-D extracellular matrix provides a spatially complex and biomechanically demanding substrate for cell migration, thereby differing from cell migration across planar ligands. Highly adhesive and integrin-dependent migration strategies detected in morphologically large and slowly migrating cells may result in reorganization of the extracellular matrix, whereas leukocytes favor largely integrin-independent, rapid, and flexible migration strategies lacking typical focal adhesions and structural matrix remodeling.

The extracellular domain of CD4 receptor possesses a protein kinase activity

The CD4 receptor of T-helper cells is an essential participant in immune response formation and HIV infection. We report here that the extracellular domains of CD4 receptor can catalyze the phosphotransferase (kinase) reaction. Incubation of rsCD4 in solution with [gamma-32P]ATP results in the Ca2+-dependent autophosphorylation of the protein presumably at a His residue because the reaction is prevented by the diethylpyrocarbonate treatment. The rsCD4 phosphorylates milk casein or human plasma proteins as a Ser/Thr protein kinase.

Focussing human B cell specificity by immunoselection via antigen-presenting cells in vitro

We present a protocol for in vitro immunization of B cells using monocyte-derived accessory cells (MoAC). MoAC are developed from human peripheral blood monocytes in culture and represent functionally competent inducers of antigen-specific immune responses. Using MoAC, we attempted to immunoselect TT-specific lymphocytes by rosetting. Adherent human MoAC were pulsed with tetanus toxoid (TT) and allowed to form clusters with autologous lymphocytes, followed by removal of non-adherent cells. After one week of culture, a specific anti-TT antibody response emerged on a low background of unspecific Ig. In comparison, cultures which had not been selected for adherent cells produced a high polyclonal background. Our results demonstrate that from peripheral blood cells, previously not a favourable source for in vitro immunization, in a majority of tests antigen-specific B cells could efficiently be immunoselected via adherence to autologous antigen-presenting cells, leading to a high-titre in vitro immunization.

Potential effect of cytokines on transgene expression in primary fibroblasts implanted into the rat brain

Fibroblasts genetically modified with retroviral vectors fail to demonstrate long-term transgene expression upon implantation into the body. Although the mechanisms behind this phenomenon have not been elucidated, one likely cause is the response of the host to the graft. For example, genetically modified fibroblasts grafted into the brain are surrounded by activated microglia and astrocytes. The apparent inflammatory response can last for several weeks. In addition, the center of the graft is typically infiltrated with macrophage-like cells that appear to reside continuously within the graft. This proximity of inflammatory cells to the graft suggests that these cells may somehow influence transgene expression. In the current study, an in vitro model was used to test the effect cytokines [transforming growth factor-beta1 (TGF-beta1), interleukin-1beta, (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha)] that are typically released by peripheral macrophages, activated microglia and/or astrocytes have on long-terminal repeat (LTR)-driven transgene expression in primary fibroblasts. Our data demonstrate that these cytokines can significantly reduce the steady-state level of proviral mRNA. The amount of proviral mRNA returned to control levels within 24 h if the cytokines were removed. In addition, the down-regulation of proviral mRNA levels could be prevented if the cells were incubated with dexamethasone (25 microM) concurrent with the introduction of cytokines. These data demonstrate that cytokines can down-regulate LTR-driven transgene expression in primary fibroblasts maintained in culture. This interaction may be a major reason why transduced cells do not demonstrate long-term transgene expression in vivo.

Immunosuppression and cytokine production in mice infested with Ixodes ricinus ticks: a possible role of laminin and interleukin-10 on the in vitro responsiveness of lymphocytes to mitogens

T cells from BALB/c mice infested 9 days before with Ixodes ricinus nymphs had a suppressed response to in vitro concanavalin A (Con A) stimulation compared to cells from uninfested mice. When laminin (the main component of the extracellular matrix) was used as a coating agent, the Con A response of naive mice was characterized by a decrease in cell proliferation, whereas there was no significant effect on the mitogen response of cells from infested mice. In contrast, an increased response to lipopolysaccharide (LPS) was observed when assaying lymph node cells of infested mice, probably reflecting an increase in B-lymphocyte number or activity. LPS cell stimulation was not modified by laminin. Supernatants of lymph node cells, taken 9 days after the first infestation of mice, stimulated with Con A in vitro, contained interleukin-10 (IL-10) but no significant levels of IL-5 as tested by enzyme-linked immunosorbent assay. At this stage of the infestation all T cells reactive with tick antigens generated in lymph nodes that drain the tick fixation site, were CD4+ cells, as determined by CD4+ depletion. With cells taken 9 days after the third infestation an increase of IL-5 and IL-10 was observed. The IL-10 levels were higher than the IL-5. According to these observations, we conclude that the reduction of T-cell proliferation in response to Con A observed in lymph node cells from infested mice, may be due to the combined effect of laminin interaction with T lymphocytes during migration and IL-10 production by these lymphocytes.

Stimulated natural killer cells secrete factors with chemotactic activity, including NAP-1/IL-8, which supports VLA-4- and VLA-5-mediated migration of T lymphocytes

In vivo, natural killer (NK) cells dominate among the early invading cells in allografts and virus-infected tissues, and they are followed later by an influx of T cells. The same sequence of events was seen in our modified Boyden chamber assay. The migration of both CD3+/CD4+ and CD3+/CD8+ cells through fibronectin-coated filters increased after co-culture with NK cells. The migratory response to a soluble factor from NK cells supernatants was predominantly chemotactic rather than chemokinetic. Endogenous NK cells, purified in the presence of human serum albumin, did not induce T cell chemotaxis, but NK cells which were purified in the presence of 10% fetal calf serum (FCS), or which were activated in the absence of FCS with 10(-4) M histamine, with 300 IU/ml interleukin (IL)-2, or with a combination of 10 IU/ml IL-2 and 10 micrograms/ml CD16 monoclonal antibody increased T cell migration by 30-70%. Both the random and chemotactic migration were dependent on fibronectin receptors VLA-4 and VLA-5 on T cells. About 60% of the chemotactic was neutralized by NAP-1/IL-8 polyclonal antibody. Northern blot analysis revealed IL-8 mRNA expression in highly purified, stimulated NK cells; dimeric IL-8 protein secreted by NK cells was detected by immunoblotting, and, in immunofluorescence staining IL-8 was visualized in NK cells. These observations suggest that NK cells, early invaders in the foci of injury, participate in the initiation of a specific immune response by facilitating T cell recruitment.

Homotypic leukocyte aggregation triggered by a monoclonal antibody specific for a novel epitope expressed by the integrin beta 1 subunit: conversion of nonresponsive cells by transfecting human integrin alpha 4 subunit cDNA

The monoclonal antibody 33B6 was found to be specific for the beta 1 integrin subunit. Treatment of leukocytes with this antibody induced a vigorous homotypic aggregation that had similar physiologic conditions as aggregation induced by a monoclonal antibody specific for the alpha 4 subunit. Expression of a beta 1 subunit on the cell surface was not sufficient for mAb 33B6-mediated aggregation to occur, since cells of the K562 erythroleukemia line failed to respond even though they expressed the beta 1 subunit and the 33B6 epitope. However, after transfection with cDNA encoding the alpha 4 subunit, K562 cells acquired the ability to aggregate in response to mAb 33B6 binding. By contrast, mAb 33B6 blocked cell binding to the endothelial surface protein vascular cell adhesion molecule-1 and the extracellular matrix protein fibronectin. These results suggest that the beta 1 epitope defined by mAb 33B6 may play a novel role in regulating leukocyte adhesive interactions.

Involvement of a protein kinase C and protein phosphatases in adhesion of CD4+ T cells to and detachment from extracellular matrix proteins

For immune surveillance and function to be effective, T lymphocytes constantly recirculate via lymph and blood between lymphoid organs and body tissues. To enable efficient cell movement and migration, cell adhesion to components of the basement membrane and the extracellular matrix (ECM) must be a rapid and transitory process. Whether phosphorylation and dephosphorylation of cellular proteins are involved in this phenomena was explored by monitoring the adhesion of T cells to immobilized ECM proteins. A short exposure of 51Cr-labeled human CD4+ T cells to phorbol esters in vitro induced a rapid beta 1-integrin-mediated adhesion to both fibronectin and laminin, as determined by inhibition with anti-integrin antibodies. Adhesion was reversible; detachment from the immobilized ECM ligands occurred between 20 and 120 min without further intervention. This T cell adhesion was regulated by the activation of protein kinase C because (a) staurosporine and H-7 inhibitors of protein kinase C suppressed T cell adhesion, and (b) PMA-induced down-regulation of intracellular levels of protein kinase C was associated with the abrogation of the T cell adhesiveness to fibronectin and laminin. Furthermore, inhibition of protein phosphatases activity by okadaic acid delayed the detachment of the T cells from fibronectin or laminin. Thus, we suggest that T cell-ECM interactions such as adhesion and detachment are regulated, respectively, by protein kinase C and protein phosphatases.