IL-7: Comprehensive review.

OVERVIEW: IL-7 is a member of the family of cytokines with four anti-parallel α helixes that bind Type I cytokine receptors. It is produced by stromal cells and is required for development and homeostatic survival of lymphoid cells. GENOMIC ARCHITECTURE: Interleukin 7 (IL7) human IL7: gene ID: 3574 on ch 8; murine Il7 gene ID: 16,196 on ch 3. PROTEIN: Precursor contains a signal sequence, mature human IL-7 peptide 152aa, predicted 17.4kd peptide, glycosylated resulting in 25kd. Crystal structure: http://www.rcsb.org/structure/3DI2. REGULATION OF IL-7 PRODUCTION: Major producers are stromal cells in thymus, bone marrow and lymphoid organs but also reported in other tissues. Production is primarily constitutive but reported to be affected by IFNγ and other factors. IL-7 RECEPTORS: Two chains IL-7Rα (IL-7R) and γc (IL-2RG). Human IL-7R: gene ID 3575 on ch 5; human IL2RG: gene ID 3561 on ch X; mouse IL-7R: gene ID 16,197 on ch 15; murine Il2rg gene ID 16,186 on ch X. Member of γc family of receptors for cytokines IL-2, -4, -9, -15, and -21. Primarily expressed on lymphocytes but reports of other cell types. Expression in T-cells downregulated by IL-7. Low expression on Tregs, no expression on mature B-cells. Crystal structure: http://www.rcsb.org/structure/3DI2. IL-7 RECEPTOR SIGNAL TRANSDUCTION PATHWAYS: Major signals through JAK1, JAK3 to STAT5 and through non-canonical STAT3, STAT1, PI3K/AKT and MEK/ERK pathways. BIOLOGICAL ACTIVITY OF IL-7: Required for survival of immature thymocytes, naïve T-cells, memory T-cells, pro-B-cells and innate lymphocytes. Pharmacological treatment with IL-7 induces expansion of naïve and memory T-cells and pro-B-cells. ABNORMALITIES OF THE IL-7 PATHWAY IN DISEASE: Deficiencies in the IL-7 pathway in humans and mice result in severe combined immunodeficiency due to lymphopenia. Excessive signaling of the pathway in mice drives autoimmune diseases and in humans is associated with autoimmune syndromes including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, sarcoidosis, atopic dermatitis and asthma. Mutations in the IL-7 receptor pathway drive acute lymphoblastic leukemia. CLINICAL APPLICATIONS: IL-7 has been evaluated in patients with cancer and shown to expand lymphocytes. It accelerated lymphocyte recovery after hematopoietic stem cell transfer, and increased lymphocyte counts in AIDS patients and sepsis patients. Monoclonal antibodies blocking the IL-7 receptor are being evaluated in autoimmune diseases. Cytotoxic monoclonals are being evaluated in acute lymphoblastic leukemia. Drugs blocking the signal transduction pathway are being tested in autoimmunity and acute lymphoblastic leukemia.

Neck subcutaneous nodule as first metastasis from broad ligament leiomyosarcoma: a case report and review of literature.

BACKGROUND: Leiomyosarcoma usually develops in the myometrium and is characterized by a high recurrence rate, frequent hematogenous dissemination, and poor prognosis. Metastasis is usually to lungs, liver, and bone, and occasionally to the brain, but seldom to the head and neck region. Primary leiomyosarcoma very rarely arises in the broad ligament. CASE PRESENTATION: A 54-year old woman presented to the otolaryngology department with a mass in the right posterior region of the neck 4 years after surgery for a primary leiomyosarcoma of the right broad ligament. The neck mass was removed and found to be a metastatic leiomyosarcoma. Leiomyosarcoma localizations in lungs and liver were absent. Morphological examination showed both the primary and the secondary leiomyosarcomas to have features of low-grade tumors. One year after excision of the neck mass, the patient presented with tachycardia. Echocardiography detected two intracardiac nodules suggestive of metastatic tumors. Chemotherapy was administered; the disease has been stable since then. CONCLUSIONS: We report the first case of broad ligament leiomyosarcoma with the neck subcutaneous region being the first site of secondary involvement. We speculate that the Batson venous plexus might have been the pathway of dissemination.

Formalin-fixed paraffin-embedded renal biopsy tissues: an underexploited biospecimen resource for gene expression profiling in IgA nephropathy.

Primary IgA nephropathy (IgAN) diagnosis is based on IgA-dominant glomerular deposits and histological scoring is done on formalin-fixed paraffin embedded tissue (FFPE) sections using the Oxford classification. Our aim was to use this underexploited resource to extract RNA and identify genes that characterize active (endocapillary-extracapillary proliferations) and chronic (tubulo-interstitial) renal lesions in total renal cortex. RNA was extracted from archival FFPE renal biopsies of 52 IgAN patients, 22 non-IgAN and normal renal tissue of 7 kidney living donors (KLD) as controls. Genome-wide gene expression profiles were obtained and biomarker identification was carried out comparing gene expression signatures a subset of IgAN patients with active (N = 8), and chronic (N = 12) renal lesions versus non-IgAN and KLD. Bioinformatic analysis identified transcripts for active (DEFA4, TNFAIP6, FAR2) and chronic (LTB, CXCL6, ITGAX) renal lesions that were validated by RT-PCR and IHC. Finally, two of them (TNFAIP6 for active and CXCL6 for chronic) were confirmed in the urine of an independent cohort of IgAN patients compared with non-IgAN patients and controls. We have integrated transcriptomics with histomorphological scores, identified specific gene expression changes using the invaluable repository of archival renal biopsies and discovered two urinary biomarkers that may be used for specific clinical decision making.

Cell biology of IL-7, a key lymphotrophin.

IL-7 is essential for the development and survival of T lymphocytes. This review is primarily from the perspective of the cell biology of the responding T cell. Beginning with IL-7 receptor structure and regulation, the major signaling pathways appear to be via PI3K and Stat5, although the requirement for either has yet to be verified by published knockout experiments. The proliferation pathway induced by IL-7 differs from conventional growth factors and is primarily through posttranslational regulation of p27, a Cdk inhibitor, and Cdc25a, a Cdk-activating phosphatase. The survival function of IL-7 is largely through maintaining a favorable balance of bcl-2 family members including Bcl-2 itself and Mcl-1 on the positive side, and Bax, Bad and Bim on the negative side. There are also some remarkable metabolic effects of IL-7 withdrawal. Studies of IL-7 receptor signaling have yet to turn up unique pathways, despite the unique requirement for IL-7 in T cell biology. There remain significant questions regarding IL-7 production and the major producing cells have yet to be fully characterized.

IL-7-induced phosphorylation of the adaptor Crk-like and other targets.

IL-7 is required for T cell differentiation and mature T cell homeostasis and promotes pro-B cell proliferation and survival. Tyrosine phosphorylation plays a central role in IL-7 signaling. We identified by two-dimensional electrophoresis followed by anti-phosphotyrosine immunoblotting and mass spectrometry sixteen tyrosine phosphorylated proteins from the IL-7-dependent cell line D1. IL-7 stimulation induced the phosphorylation of the proteins STI1, ATIC and hnRNPH, involved in pathways related to survival, proliferation and gene expression, respectively, and increased the phosphorylation of CrkL, a member of a family of adaptors including the highly homologous Crk isoforms CrkII and CrkI, important in multiple signaling pathways. We observed an increased phosphorylation of CrkL in murine pro-B cells and in murine and human T cells. In addition, IL-7 increased the association of CrkL with the transcription factor Stat5, essential for IL-7 pro-survival activity. The selective tyrosine kinase inhibitor Imatinib. counteracted the IL-7 pro-survival effect in D1 cells and decreased CrkL phosphorylation. These data suggested that CrkL could play a pro-survival role in IL-7-mediated signaling. We observed that pro-B cells also expressed, in addition to CrkL, the Crk isoforms CrkII and CrkI and therefore utilized pro-B cells conditionally deficient in all three to evaluate the role of these proteins. The observation that the IL-7 pro-survival effect was reduced in Crk/CrkL conditionally-deficient pro-B cells further pointed to a pro-survival role of these adaptors. To further evaluate the role of these proteins, gene expression studies were performed in Crk/CrkL conditionally-deficient pro-B cells. IL-7 decreased the transcription of the receptor LAIR1, which inhibits B cell proliferation, in a Crk/CrkL-dependent manner, suggesting that the Crk family of proteins may promote pro-B cell proliferation. Our data contribute to the understanding of IL-7 signaling and suggest the involvement of Crk family proteins in pathways promoting survival and proliferation.

DNA Repair and Cytokines: TGF-ß, IL-6, and Thrombopoietin as Different Biomarkers of Radioresistance.

Double strand breaks (DSBs) induced by radiotherapy are highly cytotoxic lesions, leading to chromosomal aberrations and cell death. Ataxia-telangiectasia-mutated (ATM)-dependent DNA-damage response, non-homologous end joining, and homologous recombination pathways coordinately contribute to repairing DSBs in higher eukaryotes. It is known that the expression of DSB repair genes is increased in tumors, which is one of the main reasons for radioresistance. The inhibition of DSB repair pathways may be useful to increase tumor cell radiosensitivity and may target stem cell-like cancer cells, known to be the most radioresistant tumor components. Commonly overexpressed in neoplastic cells, cytokines confer radioresistance by promoting proliferation, survival, invasion, and angiogenesis. Unfortunately, tumor irradiation increases the expression of various cytokines displaying these effects, including transforming growth factor-beta and interleukin-6. Recently, the capabilities of these cytokines to support DNA repair pathways and the ATM-dependent DNA response have been demonstrated. Thrombopoietin, essential for megakaryopoiesis and very important for hematopoietic stem cell (HSC) homeostasis, has also been found to promote DNA repair in a highly selective manner. These findings reveal a novel mechanism underlying cytokine-related radioresistance, which may be clinically relevant. Therapies targeting specific cytokines may be used to improve radiosensitivity. Specific inhibitors may be chosen in consideration of different tumor microenvironments. Thrombopoietin may be useful in fending off irradiation-induced loss of HSCs.

Synergistic inhibitory activities of interleukin-10 and dexamethasone on human CD4+ T cells.

BACKGROUND: We have previously demonstrated that interleukin (IL)-10 synergizes with dexamethasone (Dex) in inhibiting proliferation of human T cells, stimulated in an antigen-presenting cell (APC)-dependent manner. Because IL-10 effectively inhibits APC accessory functions, the synergism could have been a result of its effect on APC. We then investigated the effects of Dex and IL-10 on T-cell subpopulations, stimulated in an APC-independent manner. METHODS: CD4 and CD8 T cells were stimulated with anti-CD3, with or without Dex and IL-10, alone or in combination. Proliferation, glucocorticoid (GC) receptor binding, anti-CD3-induced tyrosine phosphorylation, IL-2 production, and expression of IL-2 receptor alpha, beta, and gamma chains were evaluated. The pharmacologic interactions were analyzed using the isobole method. RESULTS: IL-10 synergized with Dex in inhibiting CD4 but not CD8 T-cell proliferation. The synergism was not associated with modifications of GC receptor number or affinity, nor with modifications of anti-CD3-induced tyrosine phosphorylation. IL-10 synergized with Dex in inhibiting IL-2 production and increased Dex inhibitory effect on the expression of the IL-2 receptor alpha chain, which is up-regulated by CD3 stimulation and IL-2. Only Dex inhibited the beta and gamma chain expression, which, interestingly, is not up-regulated by IL-2. IL-2, as well as IL-7 and IL-15, reversed the effects of IL-10 but not those of Dex. CONCLUSIONS: IL-10 synergizes with Dex in inhibiting CD4 T-cell proliferation. Its synergizing effect is mediated by the inhibition of IL-2 production. Dex exerts additional activities, such as the inhibition of beta and gamma chain expression. Therefore, IL-10 could be useful for the enhancement of GC-based immunosuppressive therapies.

Stemness of T cells and the hematopoietic stem cells: fate, memory, niche, cytokines.

Stem cells are able to generate both cells that differentiate and cells that remain undifferentiated but potentially have the same developmental program. The prolonged duration of the protective immune memory for infectious diseases such as polio, small pox, and measles, suggested that memory T cells may have stem cell properties. Understanding the molecular basis for the life-long persistence of memory T cells may be useful to project targeted therapies for immune deficiencies and infectious diseases and to formulate vaccines. In the last decade evidence from different laboratories shows that memory T cells may share self-renewal pathways with bone marrow hematopoietic stem cells. In stem cells the intrinsic self-renewal activity, which depends on gene expression, is known to be modulated by extrinsic signals from the environment that may be tissue specific. These extrinsic signals for stemness of memory T cells include cytokines such as IL-7 and IL-15 and there are other cytokine signals for maintaining the cytokine signature (TH1, TH2, etc.) of memory T cells. Intrinsic and extrinsic pathways that might be common to bone marrow hematopoietic stem cells and memory T lymphocytes are discussed and related to self-renewal functions.

Glomerulitis and endothelial cell enlargement in C4d+ and C4d- acute rejections of renal transplant patients.

In acute rejection after renal transplant, glomerulitis is characterized by mononuclear cells in glomerular capillaries and endothelial cell enlargement. In association with C4d deposition in peritubular capillaries, glomerulitis is a feature of acute antibody-mediated rejection. Prognosis in C4d(+) rejection is poorer than in C4d(-) rejection. We measured the glomerular endothelial cell area in C4d(+) and C4d(-) acute rejections by morphometry. In 90 acute rejection biopsies, glomerulitis was present in 36 cases (group G) and absent in 54 (group G0). In biopsies without rejections and in C4d(-) biopsies of group G0, glomerular endothelial cell area was not significantly different. In C4d(-) and C4d(+) biopsies of group G, the area in inflamed glomeruli was greater than that in C4d(-) biopsies of group G0 (P < .02 and P < .006, respectively). In C4d(+) biopsies of group G0, it was, unexpectedly, greater than in C4d(-) biopsies of group G (P < .01). Circulating posttransplant anti-human leukocyte antigen class I and class II antibodies correlated with increased endothelial cell area (P < .02). Glomerulitis was associated with diffuse C4d deposition (odds ratio [OR], 4.27; P < .004); C4d deposition was associated with steroid resistance (OR, 4.97; P < .002). Only in C4d(+) rejections did the presence of glomerulitis increase this association (OR, 9.17; P < .02). In conclusion, we quantified an increase of endothelial cell area in glomerulitis of C4d(+) and C4d(-) acute rejections (group G). An increase of this area in C4d(+) biopsies without glomerulitis (group G0) suggests complement-mediated damage in the absence of mononuclear cell margination.

Detection of nuclear and membrane antigens by liquid-based cytology following long-term storage of d1 cells, karpas cells, and peripheral blood mononuclear cells.

Immunofluorescence is the most frequently utilized technique to analyze protein expression. Fixed immunofluorescent cell suspensions, however, can only be stored for a week. We investigated whether liquid-based cytology could be used to detect antigens in cultured cells after a long storage period. Murine and human cells were fixed in PreservCyt solution, stored for various periods, and then used to perform an automated immunocytochemical analysis. Phosphorylation of the nuclear transcription factor Stat-5 induced by IL-7 was detected up to 4 months after IL-7 stimulation. Simultaneous nuclear positivity for the proliferation index MIB-1 and membrane positivity for the CD30 antigen were evident three months after fixation. Liquid-based cytology thus ensures long-lasting nuclear and membrane antigen immunoreactivity and permits the storage of cells from laborious experiments at room temperature for future analyses.

IL-7 induces myelopoiesis and erythropoiesis.

IL-7 administration to mice was previously reported to increase the mobilization of progenitor cells from marrow to peripheral sites. We now report that IL-7 increases the number of mature myeloid and monocytic cells in spleen and peripheral blood. This effect required T cells, and we show that IL-7 treatment in vivo induced GM-CSF and IL-3 production by T cells with memory phenotype. However, additional myelopoietic cytokines were shown to be involved because mice deficient in both GM-CSF and IL-3 also responded to IL-7 with increased myelopoiesis. Candidate cytokines included IFN-gamma and Flt3 ligand, which were also produced in response to IL-7. Because IFN-gamma-deficient mice also increased myelopoiesis, it was suggested that IL-7 induced production of redundant myelopoietic cytokines. In support of this hypothesis, we found that the supernatant from IL-7-treated, purified T cells contained myelopoietic activity that required a combination of Abs against GM-CSF, IL-3, and anti-Flt3 ligand to achieve maximum neutralization. IL-7 administration increased the number of splenic erythroid cells in either normal, Rag1 or GM-CSF-IL-3-deficient mice, suggesting that IL-7 might directly act on erythroid progenitors. In support of this theory, we detected a percentage of TER-119(+) erythroid cells that expressed the IL-7Ralpha-chain and common gamma-chain. Bone marrow cells expressing IL-7R and B220 generated erythroid colonies in vitro in response to IL-7, erythropoietin, and stem cell factor. This study demonstrates that IL-7 can promote nonlymphoid hemopoiesis and production of cytokines active in the host defense system in vivo, supporting its possible clinical utility.

Gene expression of transforming growth factor beta receptors I and II in non-small-cell lung tumors.

Transforming growth factor (TGF)beta inhibits normal epithelial cell proliferation. A decreased expression of TGFbeta receptors (TbetaR) has been associated with loss of TGFbeta sensitivity and enhanced tumor progression in many types of cancer. Although lung cancer is one of the leading causes of cancer death, a comparative analysis of TbetaR mRNA and protein expression in non-small-cell (NSC) lung tumors has not been performed. Lung tumor tissues and control non-lesional lung tissues were obtained from 17 patients undergoing thoracotomy for primary NSC lung tumors in clinical stage II. Each tissue sample was studied for TbetaRI and TbetaRII mRNA and immunoreactive protein expression, using a semi-quantitative reverse transcription-PCR method, and a quantitative immunohistochemistry method, respectively. TbetaRI protein expression was higher in tumors than in controls (p=0.0005) and a similar trend was present at the mRNA level. TbetaRII protein expression was not significantly different between tumors and controls, however an intense peri-nuclear staining for TbetaRII was observed in several tumor cells. TbetaRII mRNA levels were lower in tumors than in controls (p=0.005) and an inverse relation between TbetaRII mRNA and protein expression was detected in tumors (p=0.0013). Our findings suggest an altered function of the TbetaR system in NSC lung cancer.

Acute rejection and graft survival in renal transplanted patients with viral diseases.

Transplanted patients are susceptible to viral infections; thus, the aim of this study was to evaluate the features of acute rejections and the outcome of the renal graft in transplanted patients with herpes virus diseases. Renal biopsies from 30 renal transplanted patients undergoing early acute rejection (type IA and IB according to the Banff 97 classification) were evaluated. In total, 15 of these patients experienced cytomegalovirus (CMV) or Epstein-Barr virus disease within the first year following transplantation (group I) and 15 patients showed no evidence of viral infection (group II). No significant differences between the groups in terms of age, male/female ratio, living/cadaveric donor ratio, cold ischemia time, HLA A-B matching, pretransplant panel reactive antibody test, occurrence of post-transplant tubular necrosis, plasma levels of cyclosporin A and mean percent increase of serum creatinine at the time of the biopsy were observed. In group I biopsies, the mean number of interstitial plasma cells, as well as the mean number of CD79a-positive cells (B lymphocytes and plasma cells) was significantly higher than in group II (P<0.01 and <0.01, respectively). There was a positive correlation between the number of infections and the number of plasma cells (P<0.05). In transplanted patients, CMV can trigger the formation of anti-endothelial cell antibodies, which have been proposed to play a role in antibody-mediated rejections. We investigated whether a deposition of C4d, a marker of antibody-mediated reactions, was present in renal peritubular capillaries. In group I C4d deposition was found in five cases, while in group II it was not observed (P<0.05). In group I, 7/15 patients developed chronic allograft nephropathy vs 1/15 patients in group II (P<0.05). The estimated 1-, 5- and 8-year cumulative graft survival rates were 80, 66 and 57%, respectively, in group I, while in group II the estimated 8-year cumulative survival rate was 100% (P<0.05). In conclusion, acute rejection biopsies of patients with viral infections displayed plasma cell infiltrates and, in several cases, C4d deposition. Our study suggests a role of B lymphocytes in the pathology of these rejections and confirms the association between viral infections and poor graft survival.

Inhibition of cGMP-dependent protein kinases potently decreases neutrophil spontaneous apoptosis.

The signalling pathways mediating neutrophil spontaneous apoptosis are still largely unknown. We report that the indolocarbazole compound KT5823, a specific inhibitor of cGMP-dependent protein kinases (cGK), dose-dependently inhibited spontaneous apoptosis of neutrophils. At the concentration eliciting the maximum effect (8 microM), it decreased apoptosis from 72.42+/-12.79% to 45.86+/-7.22% (p=0.0002, n=6). Similarly, the isoquinoline sulfonamide compound H89, another cGK inhibitor, prevented neutrophil apoptosis. At the concentration eliciting the maximum effect (20 microM), it decreased apoptosis from 72.42+/-12.79% to 31.84+/-10.70% (p=0.0004, n=6). The maximum effect of KT5823 and H89 was comparable to that of GM-CSF and LPS, respectively. Moreover, YC-1, a soluble guanylate cyclase activator, and 4-([3',4',-(methylenedioxy)benzyl]amino)-6-methoxyquinazoline, a specific phosphodiesterase 5 inhibitor, enhanced neutrophil apoptosis, and their effect was antagonised by KT5823. Taken together, these observations highlight a new role of cGK as important mediators of neutrophil spontaneous apoptosis.