IL-7 in allogeneic transplant: clinical promise and potential pitfalls

Identification of Key Pathways and Genes in Advanced Coronary Atherosclerosis Using Bioinformatics Analysis

Background

Coronary artery atherosclerosis is a chronic inflammatory disease. This study aimed to identify the key changes of gene expression between early and advanced carotid atherosclerotic plaque in human.

Methods

Gene expression dataset GSE28829 was downloaded from Gene Expression Omnibus (GEO), including 16 advanced and 13 early stage atherosclerotic plaque samples from human carotid. Differentially expressed genes (DEGs) were analyzed.

Results

42,450 genes were obtained from the dataset. Top 100 up- and downregulated DEGs were listed. Functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) identification were performed. The result of functional and pathway enrichment analysis indicted that the immune system process played a critical role in the progression of carotid atherosclerotic plaque. Protein-protein interaction (PPI) networks were performed either. Top 10 hub genes were identified from PPI network and top 6 modules were inferred. These genes were mainly involved in chemokine signaling pathway, cell cycle, B cell receptor signaling pathway, focal adhesion, and regulation of actin cytoskeleton.

Conclusion

The present study indicated that analysis of DEGs would make a deeper understanding of the molecular mechanisms of atherosclerosis development and they might be used as molecular targets and diagnostic biomarkers for the treatment of atherosclerosis.

Identification of NF-κB inhibitors following Shenfu injection and bioactivity-integrated UPLC/Q-TOF-MS and screening for related anti-inflammatory targets in vitro and in silico

ETHNOPHARMACOLOGICAL RELEVANCE

Shenfu injection (SFI) is a commercial medicinal product approved by the China Food and Drug Administration that is widely used in the treatment of stroke and coronary heart disease. However, the material basis and the mechanism of SFI are not fully understood.

AIM OF THE STUDY

With network pharmacology analysis, our research committed to identify the anti-inflammatory ingredients and mechanism of SFI by combining high-throughput screening.

MATERIALS AND METHODS

We developed a bioactivity-based UPLC/Q-TOF-MS method followed by network pharmacology and identified the anti-inflammatory active ingredients of SFI from two different perspectives of network computing and high throughput screening. Then we verified the anti-inflammatory effect of SFI in vitro with endothelial cells. After detecting the cell viability, the expression of interleukin-6 (IL-6), inhibitor of nuclear factor kappa-B kinase (IKK), phosphorylated IKK, phosphorylated NF-κB and phosphorylated IκB-α from the supernatant were determined.

RESULTS

SFI could significantly suppress inflammatory responses, and the mechanism may be via an NF-κB-dependent pathway. The results of high throughput screening (HTS) revealed that protopanaxadiol glycosides (ginsenosides Rb1, Rb2, Rb3, Rc and Rd), protopanaxatriol glycosides (ginsenosides Rg1, Rg2, Re, Rf and F1), diester-type alkaloids (fuziline and neoline) and aconine derivatives (mesaconine and benzoyl-mesaconine) have anti-NF-κB activity. The three compounds (including benzoyl-mesaconine, fuziline and neoline) are the first reported SFI compounds to have NF-κB inhibitor activity.

CONCLUSIONS

SFI may play a critical role in counteracting inflammation through the NF-κB signaling pathway. The active ingredients are protopanaxadiol glycosides, protopanaxatriol glycosides, diester-type alkaloids and aconine derivatives.

Treatment with Interleukin-7 Restores Host Defense against Pneumocystis in CD4+ T-Lymphocyte-Depleted Mice

Pneumocystis pneumonia (PCP) is a major cause of morbidity and mortality in patients with HIV infection. CD4(+) T lymphocytes are critical for host defense against this infection, but in the absence of CD4(+) T lymphocytes, CD8(+) T lymphocytes may provide limited host defense. The cytokine interleukin-7 (IL-7) functions to enhance lymphocyte proliferation, survival, and recruitment of immune cells to sites of infection. However, there is little known about the role of IL-7 in PCP or its potential use as an immunotherapeutic agent. We hypothesized that treatment with recombinant human IL-7 (rhIL-7) would augment host defense against Pneumocystis and accelerate pathogen clearance in CD4-depleted mice. Control and CD4-depleted mice were infected with Pneumocystis, and rhIL-7 was administered via intraperitoneal injection. Our studies indicate that endogenous murine IL-7 is part of the normal host response to Pneumocystis murina and that administration of rhIL-7 markedly enhanced clearance of Pneumocystis in CD4-depleted mice. Additionally, we observed increased recruitment of CD8(+) T lymphocytes to the lungs and decreased apoptosis of pulmonary CD8(+) T lymphocytes in rhIL-7-treated animals compared to those in untreated mice. The antiapoptotic effect of rhIL-7 was associated with increased levels of Bcl-2 protein in T lymphocytes. rhIL-7 immunotherapy in CD4-depleted mice also increased the number of gamma interferon (IFN-γ)-positive CD8(+) central memory T lymphocytes in the lungs. We conclude that rhIL-7 has a potent therapeutic effect in the treatment of murine Pneumocystis pneumonia in CD4-depleted mice. This therapeutic effect is mediated through enhanced recruitment of CD8(+) T cells and decreased apoptosis of lung T lymphocytes, with a preferential action on central memory CD8(+) T lymphocytes.

T cell reconstitution in allogeneic haematopoietic stem cell transplantation: prognostic significance of plasma interleukin-7

Infections and acute graft-versus-host disease (aGVHD) are major causes of treatment-related mortality and morbidity following allogeneic haematopoietic stem cell transplantation (HSCT). Both complications depend on reconstitution of the T-lymphocyte population based on donor T cells. Although it is well established that Interleukin-7 (IL-7) is a cytokine essential for de novo T cell development in the thymus and homoeostatic peripheral expansion of T cells, associations between circulating levels of IL-7 and T cell reconstitution following HSCT have not been investigated previously. We prospectively measured IL-7 levels in 81 patients undergoing myeloablative HSCT with either sibling donor or an unrelated donor. Plasma IL-7 levels peaked at day +7 post-transplant (1.3-82.4 pg/ml), at the time of maximal lymphopaenia. In multivariate analysis, peak levels of IL-7 were significantly higher in patients treated with anti-thymocyte globulin (ATG) compared with those not treated with ATG (P = 0.0079). IL-7 levels at day +7 were negatively associated with T cell counts at day +30 to +60 (at day +60: CD3(+) : β = -10.6 × 10(6) cells/l, P = 0.0030; CD8(+) : β = -8.4 × 10(6) cells/l, P = 0.061; CD4(+) : β = -2.1 × 10(6) cells/l, P = 0.062) in multivariate analyses. In adults, high IL-7 levels were associated with increased risk of grade II-IV aGVHD (OR = 5.4, P = 0.036) and reduced overall survival (P = 0.046). The present data indicate that high plasma levels of IL-7 in the early post-transplant period are predictive for slow T cell reconstitution, increased risk of aGVHD and increased mortality following HSCT.

T-lymphocyte recovery and function after cord blood transplantation

The Szabolcs laboratory is focused on understanding the biology of donor-derived cellular immunity in recipients of allogeneic hematopoietic cell transplantation that can be translated into new immunotherapy strategies. To this end, we are focused on developing novel laboratory approaches to analyze and augment immune recovery for high risk patient cohorts without increasing graft-versus-host disease. Much of our work has focused on unrelated cord blood transplantation as the dominant clinical scenario and laboratory model. Our overarching goal is to minimize transplant-related mortality and morbidity and render HLA-mismatched unrelated cord blood transplant, a widely accepted safe cellular therapy. Donor leukocyte infusions in the allogeneic hematopoietic transplant setting can provide a clinically relevant boost of immunity to reduce opportunistic infections and to increase graft-versus-leukemia activity. Our laboratory has a major focus toward ex vivo expansion of cord blood T cells with anti-apoptotic cytokines and CD3/CD28 co-stimulatory beads. Expanded lymphocytes lack alloreactivity against recipient and other allogeneic cells indicating a favorable safety profile from graft-versus-host disease. Nevertheless, expanded T cells can be primed subsequently against lymphoid and myeloid leukemia cells to generate tumor-specific cytotoxic T cells. These findings offer a major step in fulfilling critical biological requirements to quickly generate a cellular product ex vivo, using a negligible fraction of a cord blood graft that provides a flexible adoptive immunotherapy platform for both children and adults.

The immunobiology of cord blood transplantation

Despite significant recent advances in the applicability and outcome following unrelated cord blood transplantation (UCBT), infections remain a major cause of mortality associated with poor immune recovery in the first 6 months after UCBT. Enhanced immune reconstitution not only could improve survival by reduced transplant related mortality, but may also favorably impact on relapse incidence by improved graft-versus-leukemia effects. This review will summarize our current understanding of the biology of immune recovery post-UCBT with an emphasis on adaptive T cell dependent immunity. New efforts to boost immunity will be also highlighted including our own laboratory, where ex vivo T cell expansion is pursued towards adoptive immunotherapy.

Interleukin-7 permits Th1/Tc1 maturation and promotes ex vivo expansion of cord blood T cells: a critical step toward adoptive immunotherapy after cord blood transplantation

Donor leukocyte infusions (DLI) in the allogeneic hematopoietic transplant setting can provide a clinically relevant boost of immunity to reduce opportunistic infections and to increase graft-versus-leukemia activity. Despite significant advances in applicability, DLI has not been available for single-unit recipients of unrelated cord blood transplant. Ex vivo expansion of cord blood T cells can be achieved with interleukin (IL)-2 and CD3/CD28 costimulatory beads. However, significant apoptosis occurs in proliferating T cells, diminishing the yield and skewing the CD4/CD8 ratio in the T-cell population, jeopardizing the potential efficacy of DLI. In this study, we show that interleukin (IL)-7 not only reduces apoptosis of activated T lymphocytes and enhances their proliferation but also promotes functional maturation, leading to secretion of IFN-gamma and other key cytokines. Recognizing that infused T lymphocytes will need to meet microbial antigens in secondary lymphoid organs to generate effectors, we also show that expansion with IL-7 promotes the preservation of a polyclonal broad T-cell receptor repertoire and a surface phenotype that favors lymph node homing. Expanded lymphocytes lack alloreactivity against recipient and other allogeneic cells, indicating a favorable safety profile from graft-versus-host disease. Nevertheless, expanded T cells can be primed subsequently against lymphoid and myeloid leukemia cells to generate tumor-specific cytotoxic T cells. Taken together, our findings offer a major step in fulfilling critical numerical and biological requirements to quickly generate a DLI product ex vivo using a negligible fraction of a cord blood graft that provides a flexible adoptive immunotherapy platform for both children and adults.

Plasma levels of IL-7 and IL-15 in the first month after myeloablative BMT are predictive biomarkers of both acute GVHD and relapse

T-cell reconstitution after allo-SCT initially depends on homeostatic peripheral expansion of donor T cells, the level of which may promote the differentiation of alloreactive and tumor-reactive effectors. IL-7 and IL-15 exert their effect as key homeostatic cytokines. We prospectively investigated plasma levels of IL-7 and IL-15 in a homogeneous group of 40 patients in CR of their hematologic malignancy undergoing myeloablative, fully (10/10) HLA-matched BMT. IL-7 and IL-15 proceeded along similar kinetic courses, peaking at wide ranges (3.8-30.2 and 14.3-66 pg/ml, respectively) on day +14 when all patients were profoundly lymphopenic. Occurrence and grade of subsequent acute GVHD were significantly associated with heightened day +14 IL-7 and IL-15 levels. Association of peak IL-7 level to grade 2-4 acute GVHD was confirmed by Cox multivariate analysis (hazard ratio (HR)=5.38; P=0.022). Malignancy relapse was significantly associated with reduced day +14 levels of IL-15 (Cox multivariate analysis: HR=0.93; P=0.035). Plasma IL-7 and IL-15 levels in the early post transplantation period are therefore biomarkers that can help predict subsequent development of acute GVHD and malignancy relapse.

Modulating T-cell homeostasis with IL-7: preclinical and clinical studies

Interleukin-7 (IL-7) is required for the development and survival of T cells and plays a critical role in modulating T-cell homeostasis. This review will address current understanding of IL-7 biology, review recent clinical experiences and discuss potential future clinical applications of IL-7, or IL-7 blockade, in the setting of disease.

Potential contribution of IL-7 to allergen-induced eosinophilic airway inflammation in asthma

The primary function of IL-7 is to promote maturation and survival of T cells. Through microarray expression analysis, we previously observed that human blood eosinophils express mRNA for IL-7R alpha (CD127) and its common gamma chain (CD132). The purpose of this study was to determine whether eosinophils have functional IL-7 receptors and to assess the potential contribution of IL-7 to eosinophilic airway inflammation by evaluating its presence in bronchoalveolar lavage (BAL) fluid of subjects with atopic asthma before and after segmental bronchoprovocation with allergen. Immunoblot analysis revealed that CD127 is present in highly purified human blood eosinophils. Furthermore, eosinophils responded to IL-7 with phosphorylation of STAT5, up-regulation of the activation marker CD69, and prolonged survival. Neutralization of GM-CSF but not IL-5 significantly blunted these functional responses, suggesting that IL-7 mediates its effects by promoting eosinophil release of autologous GM-CSF. Notably, the suppressive effect of anti-GM-CSF on STAT5 phosphorylation occurred within 10 min of eosinophil exposure to IL-7. Thus, IL-7 likely activates eosinophil release of preformed rather than newly synthesized GM-CSF. The biological relevance of IL-7 to eosinophilia in vivo was implicated in a study of airway allergen challenge in patients with allergic asthma. IL-7 concentrations in BAL fluid increased significantly 48 h after segmental allergen challenge and were highly correlated with BAL eosinophils (r = 0.7, p < 0.001). In conclusion, the airway response to allergen is associated with the generation of IL-7, which may contribute to airway inflammation by promoting enhanced eosinophil activation and survival. Activation of eosinophils is a novel function for IL-7.

Cytokines as Adjuvants for Vaccine and Cellular Therapies for Cancer

PROBLEM STATEMENT: The development of a potent vaccine that can help treat tumors resistant to conventional cytotoxic therapies remains elusive. While part of the problem may be that trials have focused on patients with bulky residual disease, the desire to maximize responses to the vaccine remains. APPROACH: The gamma(c) family of cytokines offer a unique opportunity to support the expansion and effector potential of vaccine-responding T-cells, as well as stimulate other effectors, such as natural killer (NK) cells, to become activated. RESULTS: Combining vaccines with cytokines seems logical but can bring unwanted toxicity, as has been observed with interleukin (IL)-2. In addition, the nonspecific activation or expansion of unwanted cell subsets, such as regulatory T-cells, can contribute to global immunosuppression and limit vaccine responses. The development of IL-7 and IL-21 for the clinic offers the promise of enhancing anti-tumor responses but with far less systemic toxicity and no expansion of regulatory T cells. Preclinical studies demonstrate that IL-15 could also improve T-cell, and especially NK-cell, responses as well. CONCLUSIONS/RECOMMENDATIONS: Future work should expand the use of vaccines with IL-7, IL-21 and hopefully IL-15 in high-risk patients, and consider treatment while in a state of minimal residual disease to maximize benefit. Identifying tumors that can signal through gamma(c) cytokines will also be essential so that induction of relapse will be avoided.

Expression and production of human interleukin-7 in insect cells using baculovirus expression vector system (BEVS)

Interleukin-7 (IL-7) is a glycoprotein cytokine with significant clinical and biomedical potential, such as cancer therapy and HIV infections. Earlier it has been cloned and expressed in various protein expression systems; however, they are not efficient for large-scale production. To address this inadequacy, we report in this paper the production of recombinant human interleukin-7 (hIL-7) in insect cells. A recombinant bacmid containing hIL-7 was constructed, purified, and characterized. It was used to infect Trichoplusia ni (BT1-TN-5B1/High Fivetrade mark) insect cells. Result shows that T. ni cells successfully produce hIL-7 in shake flask cultures. A scale up to 2.5-L laboratory batch bioreactor showed the efficacy of this system for large-scale production. Our results offer a highly efficient, inexpensive, and convenient system for the large-scale expression and production of recombinant hIL-7.

Effects of IL-7 on memory CD8 T cell homeostasis are influenced by the timing of therapy in mice

IL-7 is integral to the generation and maintenance of CD8(+) T cell memory, and insufficient IL-7 is believed to limit survival and the persistence of memory CD8(+) T cells. Here, we show that during the mouse T cell response to lymphocytic choriomeningitis virus, IL-7 enhanced the number of memory CD8(+) T cells when its administration was restricted to the contraction phase of the response. Likewise, IL-7 administration during the contraction phase of the mouse T cell response to vaccinia virus or a DNA vaccine potentiated antigen-specific CD8(+) memory T cell proliferation and function. Qualitatively, CD8(+) T cells from IL-7-treated mice exhibited superior recall responses and improved viral control. IL-7 treatment during the memory phase stimulated a marked increase in the number of memory CD8(+) T cells, but the effects were transient. IL-7 therapy during contraction of the secondary CD8(+) T cell response also expanded the pool of memory CD8(+) T cells. Collectively, our studies show differential effects of IL-7 on memory CD8(+) T cell homeostasis and underscore the importance of the timing of IL-7 therapy to effectively improve CD8(+) T cell memory and protective immunity. These findings may have implications in the clinical use of IL-7 as an immunotherapeutic agent to bolster vaccine-induced CD8(+) T cell memory.

Monitoring immune dysfunctions in the septic patient: a new skin for the old ceremony

Septic syndromes represent a major although largely underrecognized healthcare problem worldwide, accounting for thousands of deaths every year. It is now agreed that sepsis deeply perturbs immune homeostasis by inducing an initial tremendous systemic inflammatory response which is accompanied by an antiinflammatory process, acting as negative feedback. This compensatory inhibitory response secondly becomes deleterious as nearly all immune functions are compromised. These alterations might be directly responsible for worsening outcome, as they may play a major role in the decreased resistance to nosocomial infections in patients who survived initial resuscitation. Consequently, immunostimulatory therapies may now be assessed for the treatment of sepsis. This review focuses on immune dysfunctions described in septic patients and on their potential use as markers on a routine standardized basis for prediction of adverse outcome or of occurrence of secondary nosocomial infections. This constitutes a prerequisite to a staging system for individualized treatment for these hitherto deadly syndromes.

Generation of pro-T cells in vitro: potential for immune reconstitution

Immunodeficient individuals are susceptible to opportunistic infection. While stem cell transplantation can restore a functional immune system, T cells are slow to recover and limited in eliciting adaptive immune responses. Approaches to selectively enhance T cell function have focused on boosting thymopoiesis to generate new T cells or expanding existing T cells. By taking advantage of the role of Notch signaling in T cell development, we have developed an in vitro system able to generate large numbers of progenitor T cells from human hematopoietic stem cells. Here, we discuss this in vitro system and its implications for the potential treatment of T cell immunodeficiency.

Haplotypes of the interleukin 7 receptor alpha gene are correlated with altered expression in whole blood cells in multiple sclerosis

IL7 regulates T cell survival, differentiation and proliferation. The alpha chain of its receptor, CD127, is polymorphic, and its haplotypes are associated with recovery from transplantation and with the autoimmune disease multiple sclerosis (MS), especially primary progressive MS (PPMS). We demonstrate that two CD127 haplotypes are highly associated with the proportion of the mRNA encoding the soluble isoform of CD127 (P<or=0.001). The soluble isoform is over-represented (P<or=0.002) in PPMS peripheral blood, irrespective of haplotype, and the MS susceptibility haplotype produces more of the soluble isoform. CD127 mRNA is underexpressed (P<or=0.001) in PPMS. Neutrophils, which produce very low levels of CD127 mRNA, were over-represented in our PPMS cohort (P<0.02). CD127 expression is lower in more differentiated cells, such as Th1s, which can be elevated in MS. A higher proportion of these two abundant cell types in peripheral blood could be the basis for the observed reduction in CD127 mRNA. CD127 expression may be a biomarker for these potentially pathologically significant leukocyte types. These significant haplotypic effects on expression are likely to modulate regulation, differentiation and function of T cell subsets in health and disease.

Rapid modifications of peripheral T-cell subsets that express CD127 in macaques treated with recombinant IL-7

BACKGROUND

Interleukin-7 (IL-7) is a key regulator of thymopoiesis and T-cell homeostasis, which increases blood T-cell number by enhancing thymic output of naive cells and peripheral proliferation.

METHODS

We explored the effects of unglycosylated recombinant simian IL-7 (rsIL-7) administration on peripheral T-cell subpopulations in healthy macaques.

RESULTS

RsIL-7 was well tolerated. Mean half-life ranged between 9.3 and 13.9 hours. Blood CD3(+)CD4(+) and CD3(+)CD8(+) lymphocyte counts decreased rapidly after each rsIL-7 administration, the duration of these effects being dependent on the frequency of administration. At treatment completion, the increased of CD3(+) lymphocytes was marked at 100 microg/kg every 2 days. CD3(+) lymphocytes that harbour the alpha chain of IL-7 receptor (CD127) and CD3(+)CD8(+) lymphocytes that expressed the proliferation marker Ki-67 exhibited a similar initial profile. The expression of the anti-apoptotic marker Bcl-2 increased in CD3(+) lymphocytes during the treatment and post-treatment period in a dose/frequency dependent manner.

CONCLUSION

RsIL-7 was well tolerated in macaques and induces rapid modifications of T-cells that express CD127.

Advances in the understanding of acute graft-versus-host disease

Allogeneic stem cell transplantation (SCT) remains the definitive immunotherapy for malignancy. However, morbidity and mortality due to graft-vs.-host disease (GVHD) remains the major barrier to its advancement. Emerging experimental data highlights the immuno-modulatory roles of diverse cell populations in GVHD, including regulatory T cells, natural killer (NK) cells, NK T cells, gammadelta T cells, and antigen presenting cells (APC). Knowledge of the pathophysiology of GVHD has driven the investigation of new rational strategies to both prevent severe GVHD and treat steroid-refractory GVHD. Novel cytokine inhibitors, immune-suppressant agents known to preserve or even promote regulatory T-cell function and the depletion of specific alloreactive T-cell sub-populations all promise significant advances in the near future. As our knowledge and therapeutic options expand, the ability to limit GVHD whilst preserving anti-microbial and tumour responses becomes a realistic prospect.