Immunology Research Unit

Haifa, Israel

Immunology Research Unit

Haifa, Israel
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Walter M.,Immunology Research Unit | Simanovich E.,Immunology Research Unit | Brod V.,Ischemia shock Research Laboratory | Lahat N.,Immunology Research Unit | And 2 more authors.
OncoImmunology | Year: 2016

Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) mediates tumor cell–macrophage interactions, and has been shown to induce both matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF). However, the epitope responsible for MMP induction is controversial, and the epitope responsible for VEGF induction is yet unknown. We generated a novel anti-EMMPRIN antibody directed against a specific epitope that successfully inhibited the production of both MMP-9 and VEGF in tumor cell–macrophage in vitro co-culture systems, exhibiting a U-shaped dose response. Furthermore, this antibody efficiently inhibited in vivo tumor progression in both the RENCA renal cell carcinoma and CT26 colon carcinoma subcutaneous tumor models, and reduced tumor size and number of metastatic foci in the 4T1 orthotopic model. This was achieved by inhibiting angiogenesis as assessed by immunohistochemical staining for the endothelial marker CD31, by inhibiting tumor cell proliferation as assessed by the staining for Ki-67, and by enhancing tumor cell apoptosis as assessed in the TUNEL assay. Moreover, administration of the antibody recruited more macrophages into the tumor, and skewed the tumor microenvironment for macrophages from TGFβ-dominated anti-inflammatory microenvironment, to a less immunosuppressive one. The antibody improved the ability of stimulated macrophages to perform antibody-dependent cell cytotoxicity (ADCC) and kill tumor cells. Thus, our new antibody maps the epitope capable of inducing both MMPs and VEGF, and places EMMPRIN as a good target for cancer therapy. © 2016 Taylor & Francis Group, LLC.

Rahat M.A.,Immunology Research Unit | Bitterman H.,Ischemia shock Research Laboratory | Lahat N.,Immunology Research Unit
Frontiers in Immunology | Year: 2011

Monocytes and Macrophages (Mo/Mφ) exhibit great plasticity, as they can shift between different modes of activation and, driven by their immediate microenvironment, perform divergent functions. These include, among others, patrolling their surroundings and main-taining homeostasis (resident Mo/Mφ), combating invading pathogens and tumor cells (classically activated or M1Mo/Mφ), orchestrating wound healing (alternatively activated or M2Mo/Mφ), and restoring homeostasis after an inflammatory response (resolution Mφ). Hypoxia is an important factor in the Mφ microenvironment, is prevalent in many physio-logical and pathological conditions, and is interdependent with the inflammatory response. Although Mo/Mφ have been studied in hypoxia, the mechanisms by which hypoxia influ-ences the different modes of their activation, and how it regulates the shift between them, remain unclear. Here we review the current knowledge about the molecular mechanisms that mediate this hypoxic regulation of Mφ activation. Much is known about the hypoxic transcriptional regulatory network, which includes the master regulators hypoxia-induced factor-1 and NF-κB, as well as other transcription factors (e.g., AP-1, Erg-1), but we also highlight the role of post-transcriptional and post-translational mechanisms. These mechanisms mediate hypoxic induction of Mφ pro-angiogenic mediators, suppress M1 Mφ by post-transcriptionally inhibiting pro-inflammatory mediators, and help shift the classically activated Mφ into an activation state which approximate the alternatively activated or resolution Mφ. © 2011 Rahat, Bitterman and Lahat.

Shapiro S.,Immunology Research Unit | Khodalev O.,Technion - Israel Institute of Technology | Bitterman H.,Carmel Medical Center | Bitterman H.,Technion - Israel Institute of Technology | And 3 more authors.
American Journal of Physiology - Cell Physiology | Year: 2010

Detachment of endothelial cells (ECs) from the extracellular matrix (ECM) is required not only for angiogenesis, but also for EC apoptosis. Matrix metalloproteinase (MMP)-2 plays a major role in the degradation of the ECM, supporting an essential role for this enzyme in both survival (angiogenesis) and death of ECs. Our aim was to study these seemingly paradoxical effects of MMP-2. We rationalized that inhibiting apoptosis would drive MMP-2 toward a prosurvival activity, clarifying the mechanisms involved. By employing specific inhibitors to two major apoptotic pathways in ECs, caspases and p38 MAPK (p38), we demonstrated that they differently affected EC behavior as well as MMP-2 expression. The p38 pathway appears to enhance MMP-2 synthesis, its partial ("intermediate") and its full activation, probably via membrane type (MT)1-MMP, while caspases enhance MMP-2 synthesis and full activation but reduce MT1-MMP and MMP-2 intermediate form. Evaluation of the reciprocal influences of MMP-2 on ECs showed that the intermediate form supported survival and migration, and the fully active form led to cell death. In addition, a pro- and intermediate form-rich environment, even in the presence of the fully active form, exerted protective effects. Thus the seemingly conflicting effects of MMP-2 on EC survival may be explained by the ratio between the MMP-2 activation forms. A regulatory loop between active MMP-2 and p38 but not between MMP-2 and caspases was also observed, suggesting that MMP-2 is downstream to caspases where it serves as an "exterminator" molecule. Altogether, modification of caspase and p38 pathways, via changes of local MMP-2, affect survival and angiogenic steps in ECs. Copyright © 2010 the American Physiological Society.

Lahat N.,Immunology Research Unit | Bitterman H.,Ischemia Shock Research Laboratory | Engelmayer-Goren M.,Immunology Research Unit | Engelmayer-Goren M.,Ischemia Shock Research Laboratory | And 3 more authors.
American Journal of Physiology - Cell Physiology | Year: 2011

Hypoxia, which characterizes ischemia, trauma, inflammation, and solid tumors, recruits monocytes, immobilizes them, and alters their function, leading to an anti-inflammatory and proangiogenic phenotype. Monocyte extravasation from the circulation and their migration in tissues are partially mediated by the balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). The mechanisms evoked by hypoxia that regulate monocyte migration and activation are not entirely clear. Specifically, the effect of hypoxia on TIMPs in these cells has hardly been investigated. We show that hypoxia reduces TIMP-2 secretion from human primary monocytes and from the monocyte-like cell lines U937 and THP-1 by three- to fourfold (P < 0.01), by inhibiting TIMP-2 transcription through mechanisms that involve the transcription factor SP-1. Hypoxia also lowers TIMP-2 protein secretion from human endothelial cells (by 2-fold, P < 0.05). TIMP-2 levels do not influence the reduced migration of THP-1 cells in hypoxia; however, low TIMP-2 levels enhance endothelial cell migration/proliferation, their ability to form tubelike structures in vitro, and the appearance of mature blood vessels in a Matrigel plug assay in vivo. Thus we conclude that reduced TIMP-2 levels secreted from both hypoxic monocytes and endothelial cells are proangiogenic. Copyright © 2011 the American Physiological Society.

Mathalone N.,Carmel Medical Center | Marmor S.,Sourasky Tel Aviv Medical Center | Marmor S.,Tel Aviv University | Rahat M.A.,Immunology Research Unit | And 6 more authors.
Graefe's Archive for Clinical and Experimental Ophthalmology | Year: 2011

Objective: Glaucoma filtering surgery may be compromised by cystic blebs which develop more frequently when anti-metabolites are used to arrest wound healing. Matrix metalloproteinases (MMPs) and the naturally occurring tissue inhibitors of metalloproteinases (TIMPs) are essential in connective tissue remodeling and wound healing. This study aimed to determine whether filtering blebs display increased expression of MMP-2, MMP-9, TIMP-1 and TIMP-2, and whether it is reflected in tear fluid. Methods: Tissue samples from leaking blebs (n = 5) and control conjunctiva (n = 5) were evaluated by immunohistochemistry for MMP-2, MMP-9, TIMP-1 and TIMP-2. Tear fluid was collected from 12 patients (12 eyes) with cystic blebs and ten patients (ten eyes) with flat blebs following trabeculectomy with Mitomycin C applied and 16 controls. MMP levels were evaluated by zymography and TIMP levels by Western blot analysis. Results: Conjunctival tissue was obtained from five eyes with cystic leaking blebs and five control eyes undergoing cataract surgery. More extensive MMP-2 and MMP-9 expression was found in the epithelial and stromal layers of blebs than in control conjunctiva. TIMP-1and TIMP-2 were expressed in all layers of the blebs, but only in the epithelium of control conjunctiva. MMP-2 and proMMP-2 activity in tears from eyes with flat blebs was significantly higher than that of controls, while activity in tears of eyes with cystic blebs was significantly higher than in those with flat blebs. There was no difference in MMP-9 activity between tears of control and post-filtering surgery eyes. Conclusions: Increased MMPs and TIMPs expression is associated with the formation of filtering blebs, suggesting involvement of MMPs in bleb remodeling. MMP-2 and ProMMP-2 levels in tear fluid may be markers for bleb configuration. © 2011 Springer-Verlag.

Perske C.,University of Gottingen | Lahat N.,Immunology Research Unit | Levin S.S.,Immunology Research Unit | Bitterman H.,Carmel Medical Center | And 2 more authors.
American Journal of Pathology | Year: 2010

Tumor-associated macrophages can potentially kill tumor cells via the high concentrations of nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS); however, tumor-associated macrophages actually support tumor growth, as they are skewed toward M2 activation, which is characterized by low amounts of NO production and is proangiogenic. We show that the mouse renal cell carcinoma cell line, RENCA, which, on stimulation, expresses high levels of iNOS mRNA, loses its ability to express the iNOS protein. This effect is mediated by the microRNA miR-146a, as inhibition of RENCA cells with anti-miR-146a restores iNOS expression and NO production (4.8 ± 0.4 versus 0.3 ± 0.1 μmol/L in uninhibited cells, P < 0.001). In vivo, RENCA tumor cells do not stain for iNOS, while infiltrating tumor-associated macrophages showed intense staining, and both cell types expressed iNOS mRNA. Restoring iNOS protein expression in RENCA cells using anti-miR-146a increases macrophage-induced death of RENCA cells by 73% (P < 0.01) in vitro and prevents tumor growth in vivo. These results suggest that, in addition to NO production by macrophages, tumor cells must produce NO to induce their own deaths, and some tumor cells may use miR-146a to reduce or abolish endogenous NO production to escape macrophage-mediated cell death. Thus, inhibiting miR-146a may render these tumor cells susceptible to therapeutic strategies, such as adoptive transfer of M1-activated macrophages. Copyright © American Society for Investigative Pathology.

Lahat N.,Immunology Research Unit | Bitterman H.,Ischemia shock Research Laboratory | Weiss-Cerem L.,Ischemia shock Research Laboratory | Rahat M.A.,Immunology Research Unit
Transplant International | Year: 2011

Transplantation involves preoperative ischemic periods that contribute to endothelial cell (EC) dysfunction and T-cell activation, leading to graft rejection. As hypoxia is a major constituent of ischemia, we evaluated its effect on the ability of ECs to express HLA-DR, which is required for presentation of antigens to T cells, and by itself serves as an important target for allogeneic T cells. Primary human umbilical vein ECs (HUVEC) and the human endothelial cell line EaHy926 were incubated in normoxia or hypoxia (PO 2 < 0.3%). Hypoxia increased the membranal expression (by 4-6 fold, P < 0.01) and secretion (by sixfold, P < 0.05) of HLA-DR protein, without influencing the accumulation of its mRNA. Alternative splicing, attenuated trafficking, or shedding from the plasma membrane were not observed, but the lysosomal inhibitor bafilomycin A1 reduced HLA-DR secretion. Hypoxia-induced endothelial HLA-DR elevated and diminished the secretion of IL-2 and IL-10, respectively, from co-cultured allogeneic CD4 + T cells in a HLA-DR-dependent manner, as demonstrated by the use of monoclonal anti-HLA-DR. Our results indicate a yet not fully understood post-translational mechanism(s), which elevate both membranal and soluble HLA-DR expression. This elevation is involved in allogeneic T-cell activation, highlighting the pivotal role of ECs in ischemia/hypoxia-associated injury and graft rejection. © 2011 European Society for Organ Transplantation.

Rahat M.A.,Immunology Research Unit | Hemmerlein B.,University of Gottingen
Frontiers in Physiology | Year: 2013

Tumor cell-macrophage interactions change as the tumor progresses, and the generation of nitric oxide (NO) by the inducible nitric oxide synthase (iNOS) plays a major role in this interplay. In early stages, macrophages employ their killing mechanisms, particularly the generation of high concentrations of NO and its derivative reactive nitrogen species (RNS) to initiate tumor cell apoptosis and destroy emerging transformed cells. If the tumor escapes the immune system and grows, macrophages that infiltrate it are reprogramed in situ by the tumor microenvironment. Low oxygen tensions (hypoxia) and immunosuppressive cytokines inhibit iNOS activity and lead to production of low amounts of NO/RNS, which are pro-angiogenic and support tumor growth and metastasis by inducing growth factors (e.g., VEGF) and matrix metalloproteinases (MMPs). We review here the different roles of NO/RNS in tumor progression and inhibition, and the mechanisms that regulate iNOS expression and NO production, highlighting the role of different subtypes of macrophages and the microenvironment. We finally claim that some tumor cells may become resistant to macrophage-induced death by increasing their expression of microRNA-146a (miR-146a), which leads to inhibition of iNOS translation. This implies that some cooperation between tumor cells and macrophages is required to induce tumor cell death, and that tumor cells may control their fate. Thus, in order to induce susceptibility of tumors cells to macrophage-induced death, we suggest a new therapeutic approach that couples manipulation of miR-146a levels in tumors with macrophage therapy, which relies on ex vivo stimulation of macrophages and their re-introduction to tumors. © 2013 Rahat and Hemmerlein.

PubMed | National Health Research Institute, Immunology Research Unit, National Institute for Cancer, Infectious Diseases Research Unit and UMAE Oncology
Type: Journal Article | Journal: Helicobacter | Year: 2016

Polymorphisms in inflammation-related genes are factors associated with the development of gastroduodenal diseases in Helicobacter pylori-infected individuals.We aimed to analyze polymorphisms in HLA-DQ, together with other host and H.pylori variables as risk factors for precancerous and cancerous gastric lesions. 1052 individuals were studied, including nonatrophic gastritis (NAG), intestinal metaplasia (IM), gastric cancer (GC) or duodenal ulcer (DU) patients, and healthy volunteers.Patients with alleles DQA*01:01 (OR 0.78), *01:02 (OR 0.29), *01:03 (OR 0.31), and DQB*02:01/02 (OR 0.40) showed a reduced risk for GC. A multivariate logistic regression analyses showed that patients with homozygote genotypes DQA1*03:01 (OR 7.27) and DQA1*04:01 (OR 8.99) and DQB1*05:01:01 (OR 12.04) were at significantly increased risk for GC. Multivariate analyses also demonstrated that age (OR>10.0) and gender (OR>2.0) were variables that influenced significantly the risk for GC, while H.pylori infection (OR>2.5) increased the risk for IM.We identified HLA-DQ alleles associated with IM and GC, and confirm that age, sex, and H.pylori infection are variables that also influence the risk for disease. The use of multiple markers, HLA-DQ alleles, age, sex, and H.pylori infection may be useful biomarkers for the early diagnosis of patients with IM and GC.

PubMed | Institute of Hematology, Immunology Research Unit, Weizmann Institute of Science, Tel Aviv University and 2 more.
Type: Journal Article | Journal: Gene therapy | Year: 2016

Small caliber synthetic vascular grafts are commonly used for bypass surgery and dialysis access sites but have high failure rates because of neointima formation and thrombosis. Seeding synthetic grafts with endothelial cells (ECs) provides a biocompatible surface that may prevent graft failure. However, EC detachment following exposure to blood flow still remains a major obstacle in the development of biosynthetic grafts. We tested the hypothesis that induced expression by the seeded EC, of vascular endothelial growth factor165 (VEGF165) and of fibulin-5, an extracellular matrix glycoprotein that has a crucial role in elastin fiber organization and increase EC adherence to surfaces, may improve long-term graft patency. Autologous ECs were isolated from venous segments, and were transduced with retroviral vectors expressing fibulin-5 and VEGF165. The modified cells were seeded on expanded polytetrafluoroethylene (ePTFE) grafts and implanted in a large animal model. Three months after transplantation, all grafts seeded with modified EC were patent on a selective angiography, whereas only a third of the control grafts were patent. Similar results were shown at 6 months. Thus, seeding ePTFE vascular grafts with genetically modified EC improved long-term small caliber graft patency. The biosynthetic grafts may provide a novel therapeutic modality for patients with peripheral vascular disease and patients requiring vascular access for hemodialysis.

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