Anti-interleukin-12/23p40 antibody attenuates chronic rejection of cardiac allografts partly via inhibition γδT cells

IL-12p40 deletion reduces M1 macrophage polarization and alleviates cardiac remodeling via regulating Th17 cells differentiation, but not γδT 17 cells, in TAC mice

BACKGROUND

The interleukin (IL) -12 p40 subunit is the common subunit of IL-12 and IL-23. It affects the immune inflammatory response, which may be closely related to cardiac remodeling. In this study, the regulatory effect of IL-12p40 knockout (KO) on cardiac remodeling was investigated, and the underlying mechanism was explored.

METHODS AND RESULTS

Mice were subjected to transverse aortic constriction (TAC) to establish a model of cardiac remodeling. First, IL-12p40 was deleted to observe its effects on cardiac remodeling and cardiac inflammation, and the results showed that IL-12p40 deletion reduced both T helper 17 (Th17) and γδT17 cell differentiation, decreased proinflammatory macrophage differentiation, alleviated cardiac remodeling, and relieved cardiac dysfunction in TAC mice. Next, we explored whether IL-17 regulated TAC-induced cardiac remodeling, and the results showed that IL-17 neutralization alleviated proinflammatory macrophage differentiation and cardiac remodeling in IL-12p40 knockout mice and WT mice. Neutralization with cluster of differentiation 4 receptor (CD4) and γδ T-cell receptor (γδTCR) antibodies inhibited pro-inflammatory macrophage polarization and improved cardiac remodeling, and CD4 neutralizing antibody (NAb) had more significant effects. Finally, adoptive transfer of Th17 cells aggravated proinflammatory macrophage differentiation and cardiac remodeling in TAC-treated CD4 KO mice, while neutralization with the IL-12p40 antibody alleviated these pathological changes.

CONCLUSION

Mainly Th17 cells but not γδT17 cells secrete IL-17, which mediates IL-12p40, promotes the polarization of proinflammatory macrophages, and exacerbates cardiac remodeling in TAC mice. IL-12p40 may be a potential target for the prevention and treatment of cardiac remodeling.

The role of temporal changes of pro-inflammatory cytokines in the development of adverse cardiac remodeling after ST-elevation myocardial infarction

Introduction

Increasing evidence supports the view that pro-inflammatory cytokines play a role in fibrosis after myocardial infarction (MI). It has been suggested that interleukin (IL)-12p40, a pro-inflammatory cytokine, can induce interferon γ (IFN-γ) and matrix metalloproteinase (MMP). However, the role of IL-12p40 in adverse cardiac remodeling (AR) after ST-elevation MI (STEMI) is unclear.

Aim

To examine the role of temporal changes of pro-inflammatory cytokines in the development of post-STEMI AR.

Material and methods

A total of 43 patients with STEMI for the first time ever were prospectively analyzed. In cardiac magnetic resonance imaging at 6 months after STEMI, a decrease of left ventricular end-diastolic volume by ≥ 12% was defined as reverse cardiac remodeling (RR), and a 12% increase was defined as AR. Cytokine concentrations were measured on the first day (baseline) and 2 weeks after STEMI.

Results

Mean IL-12p40 (59.1 ±14.5 vs. 46.7 ±9.1 pq/ml, p = 0.001), median IFN-γ (20.4 vs. 16.2 pq/ml, p = 0.048) and median MMP-2 (33866 vs. 20691 pq/ml, p = 0.011) baseline concentrations were higher in AR than RR. In patients with AR, IL-12p40 level was lower at 2 weeks than baseline (p < 0.001). There was a positive correlation between the baseline concentrations of IL-12p40, IFN-γ, MMP-2, C-reactive protein and infarct size (p < 0.05). Increased IL-12p40 and MMP-2 baseline levels were independently associated with AR (OR = 1.14, p = 0.010; OR = 1.08, p = 0.035).

Conclusions

In the initial phase of MI, greater release of pro-inflammatory cytokines was associated with increased MMP-2 levels. Elevated expression of IL-12 and MMP-2 had an independent association with AR. This may be related to the excessive inflammatory response in the initial phase of MI.

Novel Soluble Mediators of Innate Immune System Activation in Solid Allograft Rejection

During the past years, solid allograft rejection has been considered the consequence of either cellular- or antibody-mediated reaction both being part of the adaptive immune response, whereas the role of innate immunity has been mostly considered less relevant. Recently, a large body of evidence suggested that the innate immune response and its soluble mediators may play a more important role during solid allograft rejection than originally thought. This review will highlight the role of novel soluble mediators that are involved in the activation of innate immunity during alloimmune response and solid allograft rejection. We will also discuss emerging strategies to alleviate the aforementioned events. Hence, novel, feasible, and safe clinical therapies are needed to prevent allograft loss in solid organ transplantation. Fully understanding the role of soluble mediators of innate immune system activation may help to mitigate solid allograft rejection and improve transplanted recipients' outcomes.

Blockage of P2X7R suppresses Th1/Th17-mediated immune responses and corneal allograft rejection via inhibiting NLRP3 inflammasome activation

P2X7R is a vital modifier of various inflammatory and immune-related diseases. However, the immunomodulatory effects of P2X7R on corneal allograft rejection remains unknown. Here we showed that P2X7R expression was significantly upregulated in corneal grafts of allogeneic transplant mice. Pharmacological blockage of P2X7R remarkably prolonged graft survival time, and reduced inflammatory cell infiltration in corneal grafts, in particular Th1/Th17 cells. Meanwhile, the frequencies of Th1/Th17 cells in draining lymph nodes were significantly decreased in P2X7R blocked allogeneic mice. Further results showed that the effect of P2X7R on promoting Th1/Th17 mediated immune responses in corneal allograft rejection relied heavily on its activation on the NLRP3/caspase-1/IL-1β axis, while P2X7R blockage could mitigate such activation. Nevertheless, the addition of IL-1β in vivo abrogated the protective effect of P2X7R blockage on promoting corneal graft survival. These findings demonstrate that blockage of P2X7R can substantially alleviate corneal allograft rejection and promote grafts survival, highlighting it as a promising target for preventing or treating corneal allograft rejection.

miR-19a mitigates hypoxia/reoxygenation-induced injury by depressing CCL20 and inactivating MAPK pathway in human embryonic cardiomyocytes

OBJECTIVE

Myocardial infarction (MI) is a prevalent cardiovascular puzzle and a mainspring of disease-induced mortality. We performed this investigation to detect the role of putative important miRNAs or genes in MI.

RESULTS

CCL20 may be a potential therapeutic target, which was directly targeted and negatively regulated by miR-19a. CCL20 expression was significantly increased in MI tissue samples, but miR-19a was expressed at lower levels in MI. H/R treatment inhibited cell viability and induced an increase of apoptotic rate compared with Sham group. However, miR-19a mimic relieved the H/R-stimulated injury to cardiomyocytes. Protective effect of miR-19a against H/R in cardiomyocytes was reversed by CCL20 enhancement, and MAPK pathway was inactivated during this progression.

CONCLUSIONS

miR-19a eliminates the H/R-induced injury in cardiomyocytes through directly targeting CCL20 and attenuating the activity of MAPK signaling pathway. These observations highlighted the therapeutic roles of miR-19a and CCL20 for MI treatment.

Roles and Mechanisms of Interleukin-12 Family Members in Cardiovascular Diseases: Opportunities and Challenges

Cardiovascular diseases represent a complex group of clinical syndromes caused by a variety of interacting pathological factors. They include the most extensive disease population and rank first in all-cause mortality worldwide. Accumulating evidence demonstrates that cytokines play critical roles in the presence and development of cardiovascular diseases. Interleukin-12 family members, including IL-12, IL-23, IL-27 and IL-35, are a class of cytokines that regulate a variety of biological effects; they are closely related to the progression of various cardiovascular diseases, including atherosclerosis, hypertension, aortic dissection, cardiac hypertrophy, myocardial infarction, and acute cardiac injury. This paper mainly discusses the role of IL-12 family members in cardiovascular diseases, and the molecular and cellular mechanisms potentially involved in their action in order to identify possible intervention targets for the prevention and clinical treatment of cardiovascular diseases.

Deciphering the Contribution of γδ T Cells to Outcomes in Transplantation

γδ T cells are a subpopulation of lymphocytes expressing heterodimeric T-cell receptors composed of γ and δ chains. They are morphologically and functionally heterogeneous, innate yet also adaptive in behavior, and exhibit diverse activities spanning immunosurveillance, immunomodulation, and direct cytotoxicity. The specific responses of γδ T cells to allografts are yet to be fully elucidated with evidence of both detrimental and tolerogenic roles in different settings. Here we present an overview of γδ T-cell literature, consider ways in which their functional heterogeneity contributes to the outcomes after transplantation, and reflect on methods to harness their beneficial properties.

Vγ4 γδ T Cells Provide an Early Source of IL-17A and Accelerate Skin Graft Rejection

Activated γδ T cells have been shown to accelerate allograft rejection. However, the precise role of skin-resident γδ T cells and their subsets-Vγ5 (epidermis), Vγ1, and Vγ4 (dermis)-in skin graft rejection have not been identified. Here, using a male to female skin transplantation model, we demonstrated that Vγ4 T cells, rather than Vγ1 or Vγ5 T cells, accelerated skin graft rejection and that IL-17A was essential for Vγ4 T-cell-mediated skin graft rejection. Moreover, we found that Vγ4 T cells were required for early IL-17A production in the transplanted area, both in skin grafts and in the host epidermis around grafts. Additionally, the chemokine (C-C motif) ligand 20-chemokine receptor 6 pathway was essential for recruitment of Vγ4 T cells to the transplantation area, whereas both IL-1β and IL-23 induced IL-17A production from infiltrating cells. Lastly, Vγ4 T-cell-derived IL-17A promoted the accumulation of mature dendritic cells in draining lymph nodes to subsequently regulate αβ T-cell function after skin graft transplantation. Taken together, our data reveal that Vγ4 T cells accelerate skin graft rejection by providing an early source of IL-17A.

Alarmins and Their Receptors as Modulators and Indicators of Alloimmune Responses

Cell damage and death releases alarmins, self-derived immunomodulatory molecules that recruit and activate the immune system. Unfortunately, numerous processes critical to the transplantation of allogeneic materials result in the destruction of donor and recipient cells and may trigger alarmin release. Alarmins, often described as damage-associated molecular patterns, together with exogenous pathogen-associated molecular patterns, are potent orchestrators of immune responses; however, the precise role that alarmins play in alloimmune responses remains relatively undefined. We examined evolving concepts regarding how alarmins affect solid organ and allogeneic hematopoietic cell transplantation outcomes and the mechanisms by which self molecules are released. We describe how, once released, alarmins may act alone or in conjunction with nonself materials to contribute to cytokine networks controlling alloimmune responses and their intensity. It is becoming recognized that this class of molecules has pleotropic functions, and certain alarmins can promote both inflammatory and regulatory responses in transplant models. Emerging evidence indicates that alarmins and their receptors may be promising transplantation biomarkers. Developing the therapeutic ability to support alarmin regulatory mechanisms and the predictive value of alarmin pathway biomarkers for early intervention may provide opportunities to benefit graft recipients.

Comparison of arrhythmogenicity and proinflammatory activity induced by intramyocardial or epicardial myoblast sheet delivery in a rat model of ischemic heart failure

Although cell therapy of the failing heart by intramyocardial injections of myoblasts to results in regenerative benefit, it has also been associated with undesired and prospectively fatal arrhythmias. We hypothesized that intramyocardial injections of myoblasts could enhance inflammatory reactivity and facilitate electrical cardiac abnormalities that can be reduced by epicardial myoblast sheet delivery. In a rat model of ischemic heart failure, myoblast therapy either by intramyocardial injections or epicardial cell sheets was given 2 weeks after occlusion of the coronary artery. Ventricular premature contractions (VPCs) were assessed, using an implanted three-lead electrocardiograph at 1, 7, and 14 days after therapy, and 16-point epicardial electropotential mapping (EEPM) was used to evaluate ventricular arrhythmogenicity under isoproterenol stress. Cardiac functioning was assessed by echocardiography. Both transplantation groups showed therapeutic benefit over sham therapy. However, VPCs were more frequent in the Injection group on day 1 and day 14 after therapy than in animals receiving epicardial or sham therapy (p < 0.05 and p < 0.01, respectively). EEPM under isoproterenol stress showed macroreentry at the infarct border area, leading to ventricular tachycardias in the Injection group, but not in the myoblast sheet- or sham-treated groups (p = 0.045). Both transplantation types modified the myocardial cytokine expression profile. In animals receiving epicardial myoblast therapy, selective reductions in the expressions of interferon gamma, interleukin (IL)-1β and IL12 were observed, accompanied by reduced infiltration of inflammatory CD11b- and CD68-positive leukocytes, compared with animals receiving myoblasts as intramyocardial injections. Intramyocardial myoblast delivery was associated with enhanced inflammatory and immunomodulatory reactivity and increased frequency of VPCs. In comparison to intramyocardial injection, the epicardial route may serve as the preferred method of skeletal myoblast transplantation to treat heart failure.

Peroxisome proliferator-activated receptor γ deficiency in T cells accelerates chronic rejection by influencing the differentiation of CD4+ T cells and alternatively activated macrophages

Background

In a previous study, activation of the peroxisome proliferator–activated receptor γ (PPARγ) inhibited chronic cardiac rejection. However, because of the complexity of chronic rejection and the fact that PPARγ is widely expressed in immune cells, the mechanism of the PPARγ - induced protective effect was unclear.

Materials and Methods

A chronic rejection model was established using B6.C-H-2^bm12KhEg (H-2^bm12) mice as donors, and MHC II-mismatched T-cell-specific PPARγ knockout mice or wild type (WT) littermates as recipients. The allograft lesion was assessed by histology and immunohistochemistry. T cells infiltrates in the allograft were isolated, and cytokines and subpopulations were detected using cytokine arrays and flow cytometry. Transcription levels in the allograft were measured by RT-PCR. In vitro, the T cell subset differentiation was investigated after culture in various polarizing conditions. PPARγ-deficient regularory T cells (Treg) were cocultured with monocytes to test their ability to induce alternatively activated macrophages (AAM).

Results

T cell-specific PPARγ knockout recipients displayed reduced cardiac allograft survival and an increased degree of pathology compared with WT littermates. T cell-specific PPARγ knockout resulted in more CD4+ T cells infiltrating into the allograft and altered the Th1/Th2 and Th17/Treg ratios. The polarization of AAM was also reduced by PPARγ deficiency in T cells through the action of Th2 and Treg. PPARγ-deficient T cells eliminated the pioglitazone-induced polarization of AAM and reduced allograft survival.

Conclusions

PPARγ-deficient T cells influenced the T cell subset and AAM polarization in chronic allograft rejection. The mechanism of PPARγ activation in transplantation tolerance could yield a novel treatment without side effects.

NKG2D blockade attenuated cardiac allograft vasculopathy in a mouse model of cardiac transplantation

A previous paper has reported that blockade of NKG2D was effective in protecting allograft in murine models of cardiac transplantation, but the mechanism of NKG2D blockade on attenuated cardiac allograft vasculopathy (CAV) was still unknown. In our current study, we found that wild-type recipients treated with anti-NKG2D monoclonal antibody (mAb) plus cytotoxic T lymphocyte antigen (CTLA)-4-immunoglobulin (I)g showed prolonged allograft survivals (>90 days, P < 0·001) significantly and attenuated CAV. These in-vivo results correlated with reduced alloantibody production, low expression of interleukin (IL)-17 and IL-6, while infiltration of regulatory T cells increased. IL-6 administration induced shorter allograft survival and higher CAV grade in CTLA-4-Ig plus anti-NKG2D mAb-treated recipients, whereas IL-17 had no significant effect on allograft survival and CAV grade in CTLA-4-Ig plus anti-NKG2D mAb-treated recipients. Furthermore, the prolonged allograft survival induced by NKG2D blockade was abrogated partially with depletion of regulatory T cells. In conclusion, blockade of NKG2D combined with CTLA-4-Ig attenuated CAV and this effect was associated with lower alloantibody production, inhibited IL-6 expression and enhanced expansion of regulatory T cells.