The Responsiveness of Thymic Stromal Cells to semaphorin-3A.

BACKGROUND: The thymus is responsible for thymocyte differentiation into immunocompetent T lymphocytes. Different cell types in the thymic microenvironment actively cooperate in this process, interacting with the developing thymocytes through soluble factors, extracellular matrix (ECM) molecules, and receptors. In addition, this microenvironment can be influenced by several factors, such as semaphorin-3A (Sema3A), which is a multifunctional protein involved in cell migration. We evaluated the Sema3A effects on the cellular parameters and functional features of thymic stromal cells. METHODS: Thymic stromal cells were obtained by enzymatic digestion of the murine thymus. These cells were treated with Sema3A and evaluated as follows: cell morphology by scanning electron microscope, F-actin cytoskeleton and deposition of ECM molecules by fluorescence microscopy, and adhesion assays with freshly obtained thymocytes. RESULTS: The obtained thymic stroma was composed of 67% of thymic epithelial cells (TECs), and 90% of the TECs were positive for the Sema3A receptor neuropilin-1. These cells secreted CXCL12, IL-7 and extended thymocyte survival. Sema3A changed the morphology of thymic stromal cells and promoted F-actin reorganization. In addition, the fibronectin fibers were reoriented, and the laminin production was increased in Sema3A-treated thymic stromal cells. In the adhesion assays, there was an increase in the number of adhered thymocytes when thymic stromal cells were pretreated with Sema3A. CONCLUSION: Our data strongly suggest the active participation of Sema3A in thymic physiology, highlighting its role as an immunomodulatory molecule. This may provide important knowledge for understanding the interactions of thymic cells.

Potential impact of SARS-CoV-2 infection on the thymus.

Understanding the pathogenesis of certain viral agents is essential for developing new treatments and obtaining a clinical cure. With the onset of the new coronavirus (SARS-CoV-2) pandemic in the beginning of 2020, a rush to conduct studies and develop drugs has led to the publication of articles that seek to address knowledge gaps and contribute to the global scientific research community. There are still no reports on the infectivity or repercussions of SARS-CoV-2 infection on the central lymphoid organ, the thymus, nor on thymocytes or thymic epithelial cells. In this brief review, we present a hypothesis about lymphopenia observed in SARS patients and the probable pathological changes that the thymus may undergo due to this new virus.

Interactions between thymic endothelial cells and thymocytes are influenced by growth hormone.

Growth hormone (GH), in addition to its classic actions on growth and metabolism in the body, exerts pleiotropic effects on the immune system, particularly on the thymus. The aim of this study was to evaluate the influence of GH on the interactions between mature thymocytes and the thymic endothelium involved in the migratory process. To this end, fresh thymocytes (C57BL/6 mice) and the thymic endothelial cell line (tEnd.1) were used. In the cell adhesion assay, the GH-treated thymocytes adhered more to tEnd.1 cells. Additionally, there was an improvement in the deposition of fibronectin by tEnd.1 cells when co-cultured with GH-pre-treated thymocytes. Furthermore, GH induced thymocyte F-actin polymerization. In the transendothelial migration assay, a large number of GH-treated thymocytes, mainly the CD4-CD8+ subset, migrated towards the endothelium under the stimulus of insulin-like growth factor 1. In conclusion, we demonstrated the positive actions of GH in thymocyte/thymic endothelium interactions, including transendothelial migration.

Resident murine macrophage migration and phagocytosis are modulated by growth hormone.

Growth hormone (GH) plays a physiological role in the immune system. In macrophages, GH enhances the production of hydrogen peroxide, superoxide anions, nitric oxide, cytokines, and chemokines, including interferon-γ and macrophage inflammatory protein-1α. However, some of the effects of GH stimulation on the biological functions of macrophages remain to be elucidated. Herein, we showed that in vivo GH treatment resulted in decreased expression of VLA-5 and VLA-6 integrins on the macrophage surface, accompanied by a reduction in macrophage adhesion to extracellular matrix (ECM) ligands, fibronectin, and laminin. Additionally, a decrease in macrophage adhesion to laminin was observed when the cells were treated in vitro with GH. In transwell migration assays, GH-treated macrophages showed increased migration after 6 h. Although in vitro GH treatment did not influence the phagocytic activity of macrophages, when the treatment was performed in vivo, peritoneal macrophages from GH-treated mice showed a higher percentage of phagocytosis and higher phagocytic capacity than cells from control animals. These results led us to analyse the role of insulin-like growth factor-1 (IGF-1), a GH stimulated factor, on macrophage phagocytosis. We observed an increase in phagocytic activity when J774 murine macrophages were treated with IGF-1 for 24 h. Our results revealed an important role for GH in resident macrophage migration and phagocytic activity. Specifically, we demonstrate that IGF-1 may be the GH stimulated factor that induces macrophage phagocytosis in vivo.

Sphingosine-1-Phosphate Receptor 1 Is Involved in Non-Obese Diabetic Mouse Thymocyte Migration Disorders.

NOD (non-obese diabetic) mice spontaneously develop type 1 diabetes following T cell-dependent destruction of pancreatic β cells. Several alterations are observed in the NOD thymus, including the presence of giant perivascular spaces (PVS) filled with single-positive (SP) CD4⁺ and CD8⁺ T cells that accumulate in the organ. These cells have a decreased expression of membrane CD49e (the α5 integrin chain of the fibronectin receptor VLA-5 (very late antigen-5). Herein, we observed lower sphingosine-1-phosphate receptor 1 (S1P1) expression in NOD mouse thymocytes when compared with controls, mainly in the mature SP CD4⁺CD62Lhi and CD8⁺CD62Lhi subpopulations bearing the CD49e− phenotype. In contrast, differences in S1P1 expression were not observed in mature CD49e⁺ thymocytes. Functionally, NOD CD49e− thymocytes had reduced S1P-driven migratory response, whereas CD49e⁺ cells were more responsive to S1P. We further noticed a decreased expression of the sphingosine-1-phosphate lyase (SGPL1) in NOD SP thymocytes, which can lead to a higher sphingosine-1-phosphate (S1P) expression around PVS and S1P1 internalization. In summary, our results indicate that the modulation of S1P1 expression and S1P/S1P1 interactions in NOD mouse thymocytes are part of the T-cell migratory disorder observed during the pathogenesis of type 1 diabetes.

Growth hormone modulates in vitro endothelial cell migration and formation of capillary-like structures.

The generation of new blood vessels is a complex process mediated by a variety of growth factors, and the growth hormone (GH) has been shown to act as a proangiogenic factor. In fact, human GH deficiency or excess are associated with endothelial dysfunction. Moreover, mouse models have revealed the action of GH in both tissue repair and in the microvascular circulation of normal tissues. In this study, we investigated the in vitro effects of GH on endothelial cells. Using a murine endothelioma cell line (tEnd.1), we demonstrated that GH has a mitogenic effect. The hormone also affected the endothelial cellular morphology and augmented the deposition of the extracellular matrix molecules, laminin, and fibronectin, on tEnd.1 surface. GH could stimulate tEnd.1 cell fugetaxis, in transwell chambers migration assay, and increased the formation of capillary-like structures in Matrigel®-coated plates. Given the important role of angiogenesis during tissue injury, for example, at ischemic lesions, these findings shed light on therapeutic angiogenesis, particularly in pathologies where the cardiovascular system has been compromised.

Growth hormone in the presence of laminin modulates interaction of human thymic epithelial cells and thymocytes in vitro.

BACKGROUND: Several evidences indicate that hormones and neuropeptides function as immunomodulators. Among these, growth hormone (GH) is known to act on the thymic microenvironment, supporting its role in thymocyte differentiation. The aim of this study was to evaluate the effect of GH on human thymocytes and thymic epithelial cells (TEC) in the presence of laminin. RESULTS: GH increased thymocyte adhesion on BSA-coated and further on laminin-coated surfaces. The number of migrating cells in laminin-coated membrane was higher in GH-treated thymocyte group. In both results, VLA-6 expression on thymocytes was constant. Also, treatment with GH enhanced laminin production by TEC after 24 h in culture. However, VLA-6 integrin expression on TEC remained unchanged. Finally, TEC/thymocyte co-culture model demonstrated that GH elevated absolute number of double-negative (CD4(-)CD8(-)) and single-positive CD4(+) and CD8(+) thymocytes. A decrease in cell number was noted in double-positive (CD4(+)CD8(+)) thymocytes. CONCLUSIONS: The results of this study demonstrate that GH is capable of enhancing the migratory capacity of human thymocytes in the presence of laminin and promotes modulation of thymocyte subsets after co-culture with TEC.

Evaluation of wound healing and antimicrobial properties of aqueous extract from Bowdichia virgilioides stem barks in mice.

The decoction of the stem barks from Bowdichia virgilioides KUNTH is a folk remedy used to treat inflammatory disorders in Latin American and Brazil. In the present study, the wound healing activity of aqueous extract of the stem bark from B. virgilioides, called AEBv, was evaluated by the rate of healing by wound contraction and period of epithelization at different days post-wound using the wound excisional model. On day 9, the AEBv-treated animals exhibited significative reduction in the wound area when compared with controls. In wound infected with S. aureus, the AEBv significantly improved the wound contraction when compared to the saline-treated mice. The histological analysis showed that AEBv induced a collagen deposition, increase in the fibroblast count and few inflammatory cells than compared to saline-treated group. The expression of collagen type I was increased in the group treated with AEBv as indicated by immunohistochemical staining. In vitro, the AEBv was effective only against S. aureus but not against P. aeruginosa. Together, the results of this study demonstrate, for the first time, the healing and antimicrobiological effects of aqueous extract of the stem bark from B. virgilioides in the therapy of skin wounds.

Semaphorins and neuropilins: new players in the neuroendocrine control of the intrathymic T-cell migration in humans.

Cell migration is a key event for proper intrathymic T-cell differentiation, and several ligand-receptor interactions contribute to the well-co ordinated movement of developing thymocytes within the thymic lobules. Herein we summarize recent data that place semaphorin 3A (Sema3A) and its receptor neuropilin 1 (NRP1) as further players in the physiological process of cell migration in the human thymus. These molecules, as well as class A plexins (necessary for the intracellular signalling transduction triggered by Sema3A-NRP1 ligation), are constitutively expressed by both developing thymocytes and components of the thymic microenvironment, including epithelial and dendritic cells. Functionally, Sema3A decreases the adhesion of human thymocytes on thymic epithelial cell monolayers and exerts per se a dose-dependent chemorepulsive effect on human thymocytes. Moreover, Sema3A inhibits chemoattractant migratory responses induced by other ligands, including fibronectin, laminin and CXCL12 (chemokine CXC motif ligand 12). These data should be placed in the context of the concept that migration of developing T cells is a multivectorial system, in which the resulting migration vector derives from a balance of several simultaneous and/or sequential ligand-receptor pair interactions. Accordingly, semaphorins and neuropilins can be considered as further players in the system.

Growth Hormone Stimulates Murine Macrophage Migration during Aging.

BACKGROUND: Age-related impairments in macrophage functions have important consequences for the health of the elderly population. The aging process is also accompanied by a reduction in several hormones, including growth hormone (GH). Previous studies have shown that this hormone can affect macrophage activity in young individuals; however, the biological effects of GH stimulation on macrophages during aging have not yet been elucidated. OBJECTIVE: The aim of this work was to investigate the in vitro effects of GH on peritoneal macrophages from aged mice. METHODS: Peritoneal macrophages isolated from young (4 months-old) and old (12-15 months-old) mice were treated in vitro with 100 ng/mL of GH for 24 hours. After treatment, cells were analysed for cell morphology, reactive oxygen species (ROS) production, expression of integrins, cell adhesion to extracellular matrix molecules, and migration in transwell chambers. RESULTS: Although GH-treated cells from old mice exhibited decreased ROS production, we did not observe the effects of GH on macrophage morphology or macrophage phagocytic activity in young and old mice-derived cell cultures. Macrophages from old mice had increased adhesion to laminin and fibronectin substrates, as did cells obtained from young mice treated with GH, but no change was observed in the expression of integrin receptors. Furthermore, cells from old mice exhibited increased migration compared to young mice and a significant increase in macrophage migration was observed under GH stimulation. CONCLUSION: Our results showed that GH can interfere with the motility of macrophages from old mice, advancing our understanding of the interactions between the immune and neuroendocrine systems during aging.

IGF-1 increases survival of CD4+ lineage in a 2D model of thymocyte/thymic stromal cell co-culture.

Insulin-like growth factor-1 (IGF-1), in addition to its classic effects on cell proliferation and organism growth, has pleiotropic actions on the immune system, particularly on the thymus. Thus, the objective of this study was to evaluate the influence of IGF-1 on molecules involved in the survival of thymocytes in vitro using a co-culture system with thymic stromal cells obtained from C57BL/6 mice. The obtained thymic stroma has contained thymic epithelial cells, macrophages, dendritic cells, fibroblasts, and preserved the expression of the major histocompatibility complex (MHC) molecules. Fresh thymocytes were added to these cultures and the co-culture were treated daily with IGF-1 (100 ng/mL) for 3 days. In this scheme, the viability of the thymocytes was about 70%, either in the control (non-treated cells) or in the IGF-1-treated cultures. It was found that IGF-1 was able to increase the percentage of thymocytes from the CD4+ single-positive (SP) subset. This result was accompanied by an increase in the MHC II expression on thymic stromal cells and an augment on the interleukin-7 receptor (CD127) on the surface of the CD4 SP thymocytes after treatment with IGF-1. Finally, IGF-1 treatment increased the expression of the ThPOK encoding gene Zbtb7b, which is involved in the differentiation of CD4+ SP thymocytes. Our study demonstrates the participation of IGF-1 in the thymocyte/thymic stroma interactions, especially in the extended survival of the CD4+ lineage in the thymus.

Growth hormone is a modulator of lymphocyte migration.

Cell migration is crucial for intrathymic T cell differentiation and export of mature T lymphocytes to the peripheral lymphoid organs. The intrinsic regulation of T cell migration, mediated by adhesion molecules and chemokines, can be influenced by a number of endogenous factors, such as hormones, as for instance growth hormone (GH). Laminin deposition was enhanced in GH-treated mice and in GH-transgenic animals, compared with corresponding controls, and thymocyte adhesion to laminin was increased by in vivo GH treatment. An enhancing effect was also observed ex vivo in relation to the number of migrating cells in laminin-coated transwell chambers. Additionally, we found that the chemokine CXCL12, in conjunction with laminin, further enhanced the migration of thymocytes previously exposed to high concentrations of GH in vivo. Moreover, an increase in CXCL12 production has been detected in the thymus of GH-transgenic mice as well as in primary thymic epithelial cell cultures derived from these animals, as compared to age-matched wild-type counterparts. In keeping with these data, in vivo experiments showed that GH favors the trafficking of naive CD4+CD8- recent thymic emigrants to the peripheral lymph nodes. In addition, we found that migration of lymphocytes from mesenteric lymph nodes of GH-transgenic mice, triggered by the chemokine CXCL12, in conjunction with laminin or fibronectin, was enhanced, when compared to lymphocytes from control mice. Since GH-based therapy has been used in human and experimental infectious diseases, this hormone can be envisioned as an additional therapeutic tool in situations in which increasing lymphocyte numbers and migration are required for correcting a given pathological state.

CXCL12-driven thymocyte migration is increased by thymic epithelial cells treated with prolactin in vitro.

The prolactin hormone (PRL), in addition to its known effects on breast development and lactation, exerts effects on the immune system, including pleiotropic effects on the thymus. The aim of this study was to evaluate the influence of PRL on the epithelial compartment of the thymus. Thymic epithelial cells (TECs) (2BH4 cells) and fresh thymocytes were used. Immunofluorescence assay revealed that PRL treatment (10 ng/ mL) increases the deposition of laminin and expression of the chemokine CXCL12 in 2BH4 cells. However, no change was observed in the deposition of fibronectin. Moreover, PRL altered F-actin polymerisation, allowing the formation of focal adhesion complexes in treated cells. When 2BH4 cells were pre-treated with PRL, thymocyte adhesion was not altered. However, in the cell migration assay, pre-treatment with PRL potentiated the chemotactic effect of CXCL12 on the migration of total, double-positive, CD4-positive, and CD8-positive thymocytes. Together, the results of this study demonstrate the effect of PRL on thymic epithelial cells, particularly on CXCL12-driven thymocyte migration, confirming that this hormone is a regulator of thymic physiology.

Combined role of extracellular matrix and chemokines on peripheral lymphocyte migration in growth hormone transgenic mice.

Previous evidence indicated that growth hormone (GH) modulates cell migration in the thymus, and that extracellular matrix and chemokines are involved. Herein, we studied migration of peripheral lymphocytes derived from spleen and lymph nodes of GH-transgenic (GH-Tg) mice. We initially found that the relative cell numbers (normalized per gram of body weight) in lymph nodes and spleens from GH-Tg were higher at all ages tested (2-3, 7 and 12 months), as compared to wild type age-matched controls. Functionally, we found that lymphocyte migration triggered by laminin or fibronectin was enhanced in cells from GH-Tg versus control mice, independent of the organ from which the cells were derived (as ascertained in young adult animals). However, such an enhancement in migration was statistically significant only for CD4+ and CD8+ T cells from mesenteric lymph nodes. Migration of lymphocytes from mesenteric lymph nodes of GH-Tg mice, triggered by the chemokine CXCL12, in conjunction with laminin or fibronectin, was enhanced compared to lymphocytes from control mice. Rather surprisingly, the membrane levels of the corresponding extracellular matrix or chemokine receptors in peripheral lymphoid organs of GH-Tg mice did not necessarily correlate with the changes seen in migratory responses. In conclusion, our data show for the first time that GH alters lymphocyte migration in the periphery of the immune system. Considering that GH is used as an adjuvant therapeutic agent in immunodeficiencies, including AIDS, the concepts defined herein provide relevant background knowledge for future GH-related immune interventions.

Cardioprotective effects induced by hydroalcoholic extract of leaves of Alpinia zerumbet on myocardial infarction in rats.

ETHNOPHARMACOLOGY RELEVANCE: The leaves of Alpinia zerumbet is used in folk medicine in Brazil to treat hypertension. However, the cardioprotective effect of this plant has not been studied yet. AIM OF THIS STUDY: To evaluate the cardioprotective effects of the hydroalcoholic extract of the leaves of Alpinia zerumbet (AZE) against isoproterenol (ISO)-induced myocardial infarction in rats. MATERIAL AND METHODS: Rats were pretreated orally with AZE (300 mg/kg) for 30 days prior to ISO-induced myocardial infarction. The rats were sacrificed and hearts were collected and homogenized for biochemical analysis. At the end of the experiment, cardiac marker enzyme levels, histological and morphometric parameters, and hemodynamic measurements were assessed. Phytochemical compounds were verified by gas chromatography-mass spectrometry (GC-MS). RESULTS: Rats administered with ISO showed a significant increase in cardiac marker enzymes, i.e., in creatine kinase-NAC (CK-NAC) and CK-MB. Triphenyltetrazolium chloride (TTC) staining exhibited an increase in infarct areas. In the animals treated with ISO induced a significant increase in heart rate. Pretreatment with AZE significantly inhibited these effects of ISO. Moreover, biochemical findings were supported by histopathological observations. The GC-MS analyses of AZE identified volatile oils, kavalactones, and phytosterols. CONCLUSIONS: Haemodynamic, biochemical alteration and histopathological results suggest a cardioprotective protective effect of oral administration of AZE in isoproterenol induced cardiotoxicity.

Topical Growth Hormone Accelerates Wound Healing in Mice.

OBJECTIVE: The aim of this study is to investigate the effects of topical growth hormone (GH) treatment on skin wound healing in mice. MATERIALS AND METHODS: An excisional wound healing model was established on male Swiss mice, and wound healing ability was evaluated by macroscopic and histologic analyses of mice treated with topical 10-8 M and 10-7 M of GH versus the mice receiving ve- hicle alone. Wound tissues were collected on post treatment days 3, 7, and 14. Skin fragments were subjected to hematoxylin and eo- sin and Masson's trichrome staining for morphological analyses. The expression of type I collagen and platelet endothelial cell adhesion molecule 1 (CD31) was detected by immunohistochemical analysis. RESULTS: Topical treatment with GH resulted in faster wound closure rates at all time points analyzed versus those observed in the control group (day 3: 18.3 ± 3.1 vs. 44.4 ± 7.4, 43.6 ± 0.6; day 7: 41.7 ± 6.3 vs. 73.8 ± 6.6, 71.3 ± 5.8; day 12: 94.3 ± 3.9 vs. 100 ± 0, 100 ± 0). Histological analysis of the wound on post treatment day 3 revealed a more diffused in ltration of in ammatory cells in the group treated with GH. After day 7, GH-treated animals began form- ing granulation tissue, and there was an increase in in ammatory cell in ltration. The GH signi cantly increased the expression of type I collagen (day 7: 57.4 ± 4.0 vs. 120.2 ± 9.7, 79.3 ± 7.9; day 14: 218.2 ± 10.4 vs. 301.5 ± 9.1, 235.0 ± 7.5) as well as the number of blood vessels (day 7: 10.0 ± 2.4 vs. 15.3 ± 2.0, 10.1 ± 2.2; day 14: 3.2 ± 0.8 vs. 5.6 ± 2.0, 6.2 ± 2.2) in the injured area. CONCLUSIONS: The GH accelerates the closure of skin wounds by resolving the in- ammatory phase faster, accelerating reepithelialization and collagen deposition, and stimulating angiogenesis.

Metallic nanoparticles reduce the migration of human fibroblasts in vitro.

Nanoparticles have extremely wide applications in the medical and biological fields. They are being used in biosensors, local drug delivery, diagnostics, and medical therapy. However, the potential effects of nanoparticles on target cell and tissue function, apart from cytotoxicity, are not completely understood. Thus, the aim of this study was to investigate the in vitro effects of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) on human fibroblasts with respect to their interaction with the extracellular matrix and in cell migration. Immunofluorescence analysis revealed that treatment with AgNPs or AuNPs decreased collagen and laminin production at all the concentrations tested (0.1, 1, and 10 µg/mL). Furthermore, cytofluorometric analysis showed that treatment with AgNPs reduced the percentage of cells expressing the collagen receptor very late antigen 2, α2ß1 integrin (VLA-2) and the laminin receptor very late antigen 6, α6ß1 integrin (VLA-6). In contrast, AuNP treatment increased and decreased the percentages of VLA-2-positive and VLA-6-positive cells, respectively, as compared to the findings for the controls. Analysis of cytoskeletal reorganization showed that treatment with both types of nanoparticles increased the formation of stress fibres and number of cell protrusions and impaired cell polarity. Fibroblasts exposed to different concentrations of AuNPs and AgNPs showed reduced migration through transwell chambers in the functional chemotaxis assay. These results demonstrated that metal nanoparticles may influence fibroblast function by negatively modulating the deposition of extracellular matrix molecules (ECM) and altering the expression of ECM receptors, cytoskeletal reorganization, and cell migration.

Aging Increases Susceptibility to High Fat Diet-Induced Metabolic Syndrome in C57BL/6 Mice: Improvement in Glycemic and Lipid Profile after Antioxidant Therapy.

Nonalcoholic fatty liver disease (NAFLD) has been considered a novel component of the metabolic syndrome (MetS), with the oxidative stress participating in its progression. This study aimed to evaluate the metabolic profile in young and old mice with MetS, and the effects of apocynin and tempol on glycemic and lipid parameters. Young and old C57BL/6 mice with high fat diet- (HFD-) induced MetS received apocynin and tempol 50 mg·kg(-1)/day in their drinking water for 10 weeks. After HFD, the young group showed elevated fasting glucose, worsened lipid profile in plasma, steatosis, and hepatic lipid peroxidation. Nevertheless, the old group presented significant increase in fasting insulin levels, insulin resistance, plasma and hepatic lipid peroxidation, and pronounced steatosis. The hepatic superoxide dismutase and catalase activity did not differ between the groups. Tempol and apocynin seemed to prevent hepatic lipid deposition in both groups. Furthermore, apocynin improved glucose tolerance and insulin sensitivity in old mice. In summary, old mice are more susceptible to HFD-induced metabolic changes than their young counterparts. Also, the antioxidant therapy improved insulin sensitivity and glucose tolerance, and in addition, apocynin seemed to prevent the HFD-induced hepatic fat deposition, suggesting an important role of oxidative stress in the induction of NAFLD.

Uvaol attenuates pleuritis and eosinophilic inflammation in ovalbumin-induced allergy in mice.

Uvaol, a triterpene present in olives and virgin olive oil, has been shown to possess anti-inflammatory properties and antioxidant effects. However, until now, no studies have demonstrated its potential effects on allergic inflammation. The aim of this study was to evaluate the anti-inflammatory effects of uvaol in a mouse model of allergy characterized by eosinophil-dominant inflammation in actively sensitized mice. The anti-inflammatory effect of uvaol was analyzed in two murine models of allergic inflammation (pleurisy and asthma). In these models, Swiss mice were sensitized and challenged with ovalbumin (OVA). In the pleurisy model, the pleural eosinophilic inflammation and IL-5 concentrations were examined 24h after the OVA challenge, while in the asthma model were examined the airway inflammation via bronchoalveolar lavage (BAL) fluid cytology and lung histopathology analyses. Our results showed that uvaol decreased the accumulation of eosinophils and the concentration of IL-5 in pleural effluent. Uvaol also demonstrated important anti-inflammatory activity by inhibiting production of IL-5 and influx of leukocytes, mainly of eosinophils, in BAL fluid, but without interfering with levels of reactive oxygen species in leukocytes. Moreover, the eosinophil infiltration, mucus production, number of alveoli that collapsed, and IL-5 levels in the lung were clearly decreased by uvaol treatment. These findings indicate that uvaol can be a good candidate for the treatment of allergic inflammation by inhibiting eosinophil influx and IL-5 production in ovalbumin-induced allergy.

Growth hormone modulates thymocyte development in vivo through a combined action of laminin and CXC chemokine ligand 12.

Previous evidence indicates that GH modulates thymic cell migration. In this study we approached this issue in vivo, studying thymocyte migration in GH transgenic animals and in normal mice treated intrathymically with GH. Extracellular matrix and chemokines are involved in thymocyte migration. In this respect, thymocyte adhesion to laminin was higher in GH-treated animals than controls, and the numbers of migrating cells in laminin-coated Transwells was higher in GH-transgenic and GH-injected mice. Additionally, CXC chemokine ligand 12 (CXCL12)-driven migration was higher in GH-Tg and GH-treated animals compared with controls. Interestingly, although CXCR4 expression on thymocytes did not change in GH-Tg mice, the CXCL12 intrathymic contents were higher. We found that CXCL12, in conjunction with laminin, would additionally enhance the migration of thymocytes previously exposed to high concentrations of GH in vivo. Lastly, there was an augmentation of recent thymic emigrants in lymph nodes from GH-Tg and GH-injected animals. In conclusion, enhanced thymocyte migration in GH transgenic mice as well as GH-injected mice results at least partially from a combined action of laminin and CXCL12. Considering that GH is presently being used as an adjuvant therapeutic agent in immunodeficiencies, including AIDS, the concepts defined herein provide important background knowledge for future GH-based immune interventions.