Regulatory T Cells in Angiogenesis Lužnik, Zala; Anchouche, Sonia; Dana, Reza ...
The Journal of immunology (1950),
11/2020, Letnik:
205, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Regulatory T cells (Tregs) are crucial mediators of immune homeostasis. They regulate immune response by suppressing inflammation and promoting self-tolerance. In addition to their immunoregulatory ...role, a growing body of evidence highlights the dynamic role of Tregs in angiogenesis, the process of forming new blood vessels. Although angiogenesis is critically important for normal tissue regeneration, it is also a hallmark of pathological processes, including malignancy and chronic inflammation. Interestingly, the role of Tregs in angiogenesis has been shown to be highly tissue- and context-specific and as a result can yield either pro- or antiangiogenic effects. For these reasons, there is considerable interest in determining the molecular underpinnings of Treg-mediated modulation of angiogenesis in different disease states. The present review summarizes the role of Tregs in angiogenesis and mechanisms by which Tregs regulate angiogenesis and discusses how these mechanisms differ in homeostatic and pathological settings.
Edema in the central nervous system can rapidly result in life‐threatening complications. Vasogenic edema is clinically manageable, but there is no established medical treatment for cytotoxic edema, ...which affects astrocytes and is a primary trigger of acute post‐traumatic neuronal death. To test the hypothesis that adrenergic receptor agonists, including the stress stimulus epinephrine protects neural parenchyma from damage, we characterized its effects on hypotonicity‐induced cellular edema in cortical astrocytes by in vivo and in vitro imaging. After epinephrine administration, hypotonicity‐induced swelling of astrocytes was markedly reduced and cytosolic 3'‐5'‐cyclic adenosine monophosphate (cAMP) was increased, as shown by a fluorescence resonance energy transfer nanosensor. Although, the kinetics of epinephrine‐induced cAMP signaling was slowed in primary cortical astrocytes exposed to hypotonicity, the swelling reduction by epinephrine was associated with an attenuated hypotonicity‐induced cytosolic Ca2+ excitability, which may be the key to prevent astrocyte swelling. Furthermore, in a rat model of spinal cord injury, epinephrine applied locally markedly reduced neural edema around the contusion epicenter. These findings reveal new targets for the treatment of cellular edema in the central nervous system. GLIA 2016;64:1034–1049
Main Points
Epinephrine reduces hypotonic astrocyte swelling in vitro and in vivo.
Cell swelling reduction involves cAMP‐mediated Ca2+ hypoexcitability.
Epinephrine reduces trauma‐induced astrocyte swelling; a new possibility for the treatment of cellular edema.
BACKGROUNDRegulatory T (Treg) cell-based immunotherapies have been studied as potential cell-based modalities for promoting transplant survival. However, the efficacy of local delivery of Treg cells ...in corneal transplantation has not been fully elucidated. Herein, we investigated the kinetics of migration of subconjunctivally injected Treg cells and their role in promoting corneal allograft survival.
METHODSGFPCD4CD25Foxp3 Treg cells were isolated from draining lymph nodes (DLNs) of GFP transgenic mice and were subconjunctivally injected to corneal allograft recipients. Next, Treg cells, conventional T cells (Tconv) or a combination of both was locally injected to graft recipients, and graft survival was determined by evaluating opacity scores for 10 weeks. Transplanted mice without treatment served as controls. The frequencies of major histocompatibility complex-IICD11b antigen-presenting cells, IFNγCD4 Th1 cells, and CD45 cells in the DLNs and cornea were evaluated at week 2 posttransplantation using flow cytometry. Expressions of IFNγ, IL-10 and TGF-β in the grafts were assessed using reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay.
RESULTSGFP Treg cells were detected in the ipsilateral cornea and DLNs of recipients 6 hours after injection. Subconjunctival injection of Treg cells significantly decreased the frequencies of mature antigen-presenting cells in the graft and DLNs, suppressed Th1 frequencies in DLNs, and inhibited CD45 cell infiltration to the graft. Finally, locally delivered Treg cells significantly reduced the expression of IFN-γ, enhanced the levels of IL-10 and TGF-β in the graft, and promoted long-term allograft survival.
CONCLUSIONSOur study elucidates the kinetics of migration of locally delivered Treg cells and shows their role in suppressing host immune response against the allograft.
IMPORTANCE: Corneal endothelial cell (CEnC) damage and loss are major issues in eye banking and transplantation. The underlying mechanisms for CEnC loss are incompletely understood, and ...cytoprotective strategies that enhance CEnC viability could have a major effect on donor tissue quality and graft survival. OBJECTIVE: To investigate the cytoprotective role of neuropeptide α-melanocyte–stimulating hormone (α-MSH) in preventing CEnC loss in eye bank cold-stored corneas under oxidative and inflammatory cytokine-induced stress. DESIGN, SETTING, AND PARTICIPANTS: This single-center comparative research study conducted ex vivo experiments using 16 pairs of research-grade human donor corneas (courtesy of Eversight Eye Bank). Data were collected from June 2018 to November 2019, and data were analyzed from December 2019 to January 2020. EXPOSURES: Two corneas from the same donor were randomized to either control or 0.1 mmol/L of α-MSH treatment and then subjected to oxidative stress (1.4 mmol/L of hydrogen peroxide–phosphate-buffered saline for 15 minutes at 37 °C; n = 8 pairs) or cytokine-induced stress (100 ng/mL of tumor necrosis factor-α and 100 ng/mL of interferon γ for 18 hours at 37 °C; n = 8 pairs). Corneas were then stored at 4 °C. Specular images were taken at baseline and repeated twice per week using a calibrated wide-field specular microscope. CEnC viability was assessed using a fluorescent live/dead viability assay. MAIN OUTCOME AND MEASURES: Endothelial morphometry analysis, central corneal thickness measurements, and percentage of dead cells at day 11. RESULTS: Of 16 donors who provided corneas, 9 (56%) were male, and the mean (SD) age was 57.9 (12.4) years. Corneas were paired, and baseline parameters were comparable between all groups. At all time points, CEnC loss was lower in the α-MSH groups compared with the control groups. This difference was statistically significant after cytokine-induced stress (20.2% vs 35.2%; sample estimate of median, −14.9; 95% CI, −23.6 to −6.3; P = .008). Compared with the control group, α-MSH treatment resulted in a smaller increase in central corneal thickness (cytokine-induced stress: 89.3 μm vs 169.8 μm; sample estimate of median, −84.9; 95% CI, −131.5 to −41.6; P = .008; oxidative stress: 43.6 μm vs 111.9 μm; sample estimate of median, −68.8; 95% CI, −100.0 to −34.5; P = .008) and a smaller proportion of cell death (cytokine-induced stress: 2.7% vs 10.4%; difference, −7.7; 95% CI, −13.1 to −2.4; P = .01; oxidative stress: 2.9% vs 12.4%; difference, 9.5; 95% CI, 5.1 to 13.9; P = .006). CONCLUSIONS AND RELEVANCE: In this study, α-MSH treatment attenuated CEnC loss during cold storage after acute oxidative and cytokine-induced stress in human eye bank cold-stored corneas. These data suggest that supplementation of corneal storage solution with α-MSH may positively affect CEnC survival after transplant and protect the endothelium from proinflammatory cytokines and oxidative stress after full-thickness or endothelial keratoplasty, which is particularly valuable in patients at high risk of graft failure.
Purpose
Rejection is the leading cause of failure of limbal allogafts. Resident dendritic cell (DC) maturation plays a critical role in host allosensitization. There are two lineages: myeloid (mDC) ...and lymphoid (pDC), with different biological properties. The aim was to analyse the distribution of DC subtypes in limbal explant cultures on amniotic membrane (AM), cultivated on either the epithelial or stromal side and to compare the results with directly isolated cells from cadaveric whole corneoscleral tissue divided into specific areas.
Methods
The expression of CD11c (mDC), CD303/CD123 (pDC) and costimulatory molecules CD80, CD86 and activation markers HLA‐DR, CD83 was investigated by flow cytometry. Additionally, the corneal epithelium marker CK12 and ABCB5, a new epithelial stem cell marker, were investigated.
Results
Cells positive for pDC and mDC markers were found in all examined areas, with a nonsignificant prevalence of pDC. In limbal explant cultures on AM, the percentage of pDC and mDC was similar, with no statistically significant difference between cultures on epithelial or stromal sides of AM. However, with ex vivo limbal explant cultivation on AM, the pDC content declined significantly (p < 0.05) and the ABCB5 marker was likewise statistically significantly reduced.
Conclusion
This is the first study to characterize the distribution of pDC and mDC subsets in cultured and noncultured human corneolimbal tissue. Additionally, ABCB5 positive cells were identified. These findings might be important for future strategies, allowing preparation of corneolimbal allografts with optimal stem cell content for a longer lasting therapeutic effect.
PURPOSE:To develop autologous tissue-engineered conjunctival epithelial sheets to be used as advanced therapy medicinal products for severe ocular surface disorders involving the conjunctiva.
...METHODS:Methods used aimed at 1) mapping the conjunctiva for identification of the stem cell location, 2) establishing proper cell culturing conditions, 3) identifying the proper scaffold, and 4) characterizing the conjunctival grafts better. For these purposes, immunostaining and PAS staining, serial cultivation of cells, and quantitative polymerase chain reaction (INCREMENTNp63α and MUC5AC) were performed.
RESULTS:The inferior fornix represents the ideal area where to take the conjunctival biopsies from, with at least +3.58% of clonogenic colonies and higher percentages of stem cells compared with other areas, as confirmed by INCREMENTNp63α expression levels (6.79% ± 1.18%). The standard culture conditions are necessary when cells are cultured on bare plastic, while animal-free media can be used for conjunctival cell culture on the scaffold. Fibrin glue represents the ideal scaffold for production of epithelial conjunctival grafts because it allows physiological expression of the main conjunctival cell markers, with K19 as the ideal one (98.5% ± 0.5% positive cells). The presence of goblet cells (6.3% ± 1.3%) and expression of the stem cell marker INCREMENTNp63α (1.65% ± 0.35% positive cells) were also assessed.
CONCLUSIONS:Our findings pave the way for ex vivo cultivation of conjunctival epithelial cells onto a scaffold using the cell suspension technique by means of animal-free media. This would allow us to obtain conjunctival grafts for clinical purposes, thus giving a therapeutic option to patients with conjunctival diseases refractory to current therapies.
Pars plana vitrectomy (PPV) is preferred surgical procedure for the management of complex rhegmatogenous retinal detachment (RRD). The purpose of this study was to evaluate the anatomical results of ...primary PPV for the treatment of primary complex RRD and to determine the influence of lens status, tamponading agent, preoperative proliferative vitreoretinopathy (PVR) and axial length (AL) of the eye upon the anatomical outcome.
A retrospective consecutive chart analysis was performed on 117 eyes from 117 patients with complex RRD managed with PPV. Fifty-nine eyes were phakic and 58 pseudophakic eyes. All patients had a minimum follow-up period of 12 months. Eyes were classified into groups using independent variables (first classification based upon lens status and tamponade used, second classification based upon lens and PVR status and third classification based upon AL of the eye). The groups were compared for anatomical outcomes (dependent variables) using nonparametric- or, in case of normally distributed data, parametric- statistical tests.
Retinal reattachment rate in phakic eyes was 94.9% compared to 93.1% in pseudophakic, with no statistically significant difference between the two. The overall retinal reattachment rate with single surgery was 94.0%. Final reattachment rate was 97.4%. In case of established PVR ≥ C1, the reattachment rate was not statistically different (92.6%) from eyes with no PVR (91.1%) irrespective of lens status. A statistically significant difference was found between redetachment rates only between phakic eyes with gas tamponade compared to silicon oil (SO) (p = 0.001). Reattachment rate proved to be similar in both AL groups (≤24 mm and > 24 mm).
High anatomical success rate of primary vitrectomy for complex RRD with either gas or SO tamponade was achieved in phakic as well as pseudophakic eyes irrespective of AL of the eye.
Corneal transplantation is the most common form of tissue transplantation. The success of corneal transplantation mainly relies on the integrity of corneal endothelial cells (CEnCs), which maintain ...tissue transparency by pumping out excess water from the cornea. After transplantation, the rate of CEnC loss far exceeds that seen with normal aging, which can threaten sight. The underlying mechanisms are poorly understood. Alpha-melanocyte–stimulating hormone (α-MSH) is a neuropeptide that is constitutively found in the aqueous humor with both cytoprotective and immunomodulatory effects. The curent study found high expression of melanocortin 1 receptor (MC1R), the receptor for α-MSH, on CEnCs. The effect of α-MSH/MC1R signaling on endothelial function and allograft survival in vitro and in vivo was investigated using MC1R signaling-deficient mice (Mc1re/e mice with a nonfunctional MC1R). Herein, the results indicate that in addition to its well-known immunomodulatory effect, α-MSH has cytoprotective effects on CEnCs after corneal transplantation, and the loss of MC1R signaling significantly decreases long-term graft survival in vivo. In conclusion, α-MSH/MC1R signaling is critical for CEnC function and graft survival after corneal transplantation.
This perspective considers how biorepositories could influence future strategies for retinal stem cell therapies. Eye banks could set up biorepositories/biobanks where tissues are isolated, quality ...controlled, and stored for testing, research, epidemiological studies, and target validation of newly developed drugs. This could also be a breakthrough in the future delivery of ex vivo prepared customized tissue on scaffolds for transplantation purposes.
Summary
Retinal degenerative diseases are one of the main clinical causes of incurable and severe visional impairment. Thus, extensive research effort is put into the development of new causal therapeutic options. Promisingly, a number of studies showed regenerative capacity in specific retinal regions (the ciliary epithelium, retinal pigmented epithelium, iris, and Müller glia cells). However, most recent research studies are based on animal models or in vitro cultured cells, probably because of the limited availability of human posterior eye tissues (vitreous, retina, and choroid). To address this, we showed in our previous reports that eye banks with large numbers of globes collected yearly could set up biorepositories/biobanks where these precious tissues are isolated, quality controlled, and finally stored for scientists and clinicians wanting to access human tissues and test their own hypotheses. These precious human posterior eye tissues could be used for further research purposes, epidemiological studies, and target validation of newly developed drugs. In addition, this could be a promising and challenging option to retrieve potential retinal stem and progenitor cells from different parts of the retina and could be a breakthrough in the future delivery of ex vivo prepared customized (histocompatible) retinal tissue on scaffolds for transplantation purposes. In this Perspective, we will consider how the biorepositories could influence the future strategies for retinal stem cell therapies.
Significance
Retinal degenerative diseases are one of the main causes of severe vision impairment and regenerative medicine is attracting much attention as a potential therapy. Although highly desirable, the reactivation and proliferation of endogenous stem cells in vivo is not sufficient to generate enough cells to restore visual function after retinal injury. Thus, the replacement of exogenously derived normal donor cells is a promising solution. The challenge is to develop therapies with sufficient amounts of cells being harvested or expanded from donor tissues. Eye banks could overcome this issue by harvesting endogenous adult retinal stem cells from different donors.
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