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Biomedical subjects

Z Xing

Publications and source records attributed to Z Xing.

At least 73 records · Page 4Linked to original sources
PubMed1997

Overexpression of granulocyte-macrophage colony-stimulating factor induces pulmonary granulation tissue formation and fibrosis by induction of transforming growth factor-beta 1 and myofibroblast accumulation.

We have previously reported that transfer to rat lung of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene leads to high expression of GM-CSF between days 1 and 4 and granulation tissue formation followed by an irreversible fibrotic response starting from day 12 onward. In the current study, we investigated the underlying mechanisms. We found that GM-CSF overexpression did not enhance production of tumor necrosis factor-alpha in a significant manner at any time after GM-CSF gene transfer. However, the content of transforming growth factor-beta 1 in bronchoalveolar lavage fluid was markedly induced at day 4 and appeared to be maximal around day 7 and remained high at day 12. Macrophages purified from bronchoalveolar lavage fluid 7 days after GM-CSF gene transfer spontaneously released significant quantities of transforming growth factor-beta 1 protein in vitro. After peak transforming growth factor-beta 1 production was the emergence of alpha-smooth muscle actin-rich myofibroblasts. Accumulation of these cells was most prominent at day 12 within the granulation tissues and they were still present in fibrotic areas between days 12 and 24 and diminished markedly afterward. Thus, we provide the first in vivo evidence that tumor necrosis factor-alpha may be dissociated from participation in a fibrotic process in the lung and GM-CSF may play a more direct role in pulmonary fibrogenesis at least in part through its capability to induce transforming growth factor-beta 1 in macrophages and the subsequent emergence of myofibroblast phenotypes. This GM-CSF transgene lung model is useful for a stepwise dissection of both cellular and molecular events involved in pulmonary fibrosis.

Actins↗
PubMed1997

Intradermal transgenic expression of granulocyte-macrophage colony-stimulating factor induces neutrophilia, epidermal hyperplasia, Langerhans' cell/macrophage accumulation, and dermal fibrosis.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic cytokine, is up-regulated in a number of chronic skin inflammatory diseases, particularly atopic dermatitis. However, its role in these conditions remains largely unclear. To explore its function, we have established a rat intradermal transgene model by using a replication-deficient adenoviral vector expressing GM-CSF. Intradermal GM-CSF gene transfer led to a prolonged compartmentalized expression of transgene protein in the dermis. This expression induced an unexpectedly wide spectrum of pathologies in both epidermis and dermis, including neutrophilia, epidermal hyperplasia (acanthosis), an increased number of epidermal Langerhans' cells, accumulation of MHC II-positive macrophages, as well as mild eosinophilia in the dermis at earlier stages and upper dermal fibrosis at later stages. These findings thus identify GM-CSF as a potent multifunctional cytokine at skin site that is capable of evolving numerous inflammatory processes ranging from the early acute neutrophilia to later chronic fibrotic responses, and also suggest the important role of this cytokine in the development and perpetuation of pathologic changes in chronic skin inflammatory conditions including chronic atopic dermatitis. In addition, our study presents a novel model of adult normal animals that is useful for identifying and studying key cytokines involved in inflammatory skin diseases.

Animals↗
PubMed1997

A study on rIL-4 and IFN-gamma regulating IgE synthesis in bronchial asthma patients.

OBJECTIVE: To investigate the cytokines responsible for pathophysiology of asthma. METHODS: In vitro effects of recombinant interleukin-4 (rIL-4) and interferon-gamma (IFN-gamma) on synthesis of immunoglobulin E (IgE) by peripheral blood mononuclear cells (PBMC) were studied in 30 asthmatic patients and 25 normal controls. RESULTS: Spontaneous IgE synthesis by PBMC significantly increased in patients with asthma compared with the controls (t = 4.471, P < 0.001). Although the maximum amounts of IgE synthesis using PBMC after stimulation with rIL-4 were almost the same in the patients with asthma and in the controls (P > 0.05), the enhancement rate of rIL-4-induced IgE synthesis was lower in the asthma patients than in the controls (t = 4.6719, P > 0.005). IFN-gamma suppressed both spontaneous and rIL-4-induced IgE synthesis by PBMC in the asthma patients. The suppressive effect on IgE synthesis was more prominent in the patients with asthma than in the controls (t = 7.1833, P < 0.001). CONCLUSIONS: Asthma attacks are related to IgE-dependent trigger mechanism. The imbalance of IL-4 and IFN-gamma in vivo is the cause of elevated IgE than can produce mediators release and asthma attacks. IFN-gamma can inhibit IgE synthesis, so IFN-gamma may be a new approach to the treatment of asthma.

Adult↗
PubMed1996

Overexpression of RANTES using a recombinant adenovirus vector induces the tissue-directed recruitment of monocytes to the lung.

RANTES (regulated on activation, normal T cell expressed and secreted) is a member of the C-C superfamily of chemokines and is reported to function as a potent chemoattractant for monocytes, eosinophils, and a subpopulation of CD4+ T cells. Using a recombinant human type 5 adenovirus containing the murine RANTES cDNA (Ad5E3 mRANTES), which is capable of expressing biologically active cytokine upon infection, we initiated a study to characterize the biologic functions of RANTES cytokine in vivo. Intratracheal administration of Ad5E3 mRANTES targeted transient RANTES expression to the bronchial epithelium of the lung in Sprague-Dawley rats. Bronchoalveolar lavage fluids (BAL) collected at 24 h had increased chemotactic activity vs controls as measured in a murine CD4+ T cell Boyden chamber microchemotaxis assay. There was a dramatic increase in the number of cells (macrophage, monocytes, and neutrophils) recovered from BAL samples taken from Ad5E3 mRANTES-treated animals at 24 h, with a >50-fold increase in monocytes, indicating a proinflammatory effect for this cytokine in vivo. This effect on monocytes was transient, decreasing by 7 days, with evidence of increased eosinophils and lymphocytes at this time. Histologic examination of lung sections at 24 h revealed greatly increased numbers of mononuclear cells, primarily monocytes, within the lungs of Ad5E3 mRANTES-treated animals, with increased extravasation of monocytes around blood vessels, indicating an ongoing process of peripheral blood monocyte recruitment. This study provides further evidence for RANTES to be a monocyte chemoattractant in vivo.

Adenoviridae↗
PubMed1996

Adenovirus-vector-mediated cytokine gene transfer to lung tissue.

In summary, we have been able to demonstrate that adenovirus vectors are valuable tools in examining the roles played by individual cytokines in lung responses and inflammation. These viral vectors have marked trophism for the epithelial cells of the lung and are highly efficient in transferring the genes into these lining cells. This results in significant expression of cytokines both within the lumen and the parenchyma of the lung. As a result of an individual cytokine being overexpressed, there are cytokine-specific changes seen-IL-6 resulting in lymphocytosis, MIP2 resulting in neutrophil accumulation, RANTES resulting in monocyte accumulation, TGF beta resulting in monocytosis but no fibrosis, and GM-CSF most surprisingly resulting in tissue eosinophilia, granuloma formation, and subsequently the onset of fibrosis. These vectors have helped pinpoint the role of a number of the cytokines in inducing chronic inflammatory changes to the lung and imply that a single cytokine may not be the only trigger resulting in chronic changes within the lung parenchyma.

Adenoviridae↗
PubMed1996

CD40 expression by human peripheral blood eosinophils.

In this study, we have investigated CD40 expression in human peripheral blood eosinophils and in human chronically inflamed nasal tissues, i.e., nasal polyps. We show by both reverse transcriptase-PCR and Northern blot analysis that eosinophils from allergic subjects express human CD40 mRNA. We also show that constitutive CD40 mRNA expression in eosinophils could be upregulated by exposure to IgA immune complexes and downregulated by IL-10 and the synthetic steroid budesonide. In addition, we demonstrate that eosinophils express CD40 protein by flow cytometry. Such expression is biologically functional as cross-linking CD40 with CD40 mAbs enhances eosinophil survival in a dose-dependent fashion; in addition, CD40 ligation stimulates eosinophils to release GM-CSF. CD40-mediated eosinophil survival was largely inhibited by an anti-GM-CSF neutralizing antibody suggesting GM-CSF involvement in the survival enhancing mechanism. CD40 mRNA was also detected in total RNA extracted from nasal polyp tissues but not in RNA isolated from normal nasal mucosa (inferior turbinate); by immunohistochemistry, we were able to detect immunoreactive CD40 protein in a variety of cell types in the polyp stroma, but primarily in eosinophils. These observations suggest previously unforeseen interactions between eosinophils and cells expressing the CD40 ligand and, thus, novel pathways by which eosinophils may contribute to the regulation of airway inflammation.

Antibodies, Monoclonal↗
PubMed1996

Transfer of granulocyte-macrophage colony-stimulating factor gene to rat lung induces eosinophilia, monocytosis, and fibrotic reactions.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic cytokine whose expression is increased in numerous respiratory diseases, particularly in asthma. However, the role of GM-CSF in the pathogenesis of these conditions in vivo remains unclear. Here, we report the functional activities of GM-CSF highly expressed in rat lung after intrapulmonary transfer of the gene coding for murine GM-CSF by using an adenoviral vector. This high, transient expression of GM-CSF led to the sustained but self-limiting accumulation of eosinophils and macrophages associated with tissue injury in the lung followed by varying degrees of irreversible fibrotic reactions observed in later stages. These results suggest that GM-CSF plays a previously unrealized role in the development of respiratory conditions characterized by eosinophilia, granuloma and/or fibrosis and provide the rationale for targeting this molecule in these diseases.

Animals↗
PubMed1996

Gene transfer for cytokine functional studies in the lung: the multifunctional role of GM-CSF in pulmonary inflammation.

Using adenoviral-mediated gene transfer techniques, the murine granulocyte-macrophage colony-stimulating factor (GM-CSF) transgene is efficiently targeted to and highly expressed by the respiratory epithelium of rat lung. This lung tissue-directed expression of GM-CSF induces accumulation of both eosinophils and macrophages at early stages and an irreversible fibrotic reaction at later stages. These tissue responses to GM-CSF appear to be distinct from those induced by other proinflammatory cytokines, interleukin (IL)-5, IL-6, macrophage inflammatory protein-2 (MIP-2), or RANTES overexpressed in the lung. These findings clearly demonstrate that GM-CSF is more than a hematopoietic cytokine in the lung and may play a pivotal role in the multiple pathological processes underlying numerous respiratory illnesses, including asthma. In this overview, the differences in tissue responses induced by GM-CSF and other individual cytokines are highlighted. In addition, the mechanisms by which GM-CSF and other individual cytokines are highlighted. In addition, the mechanisms by which GM-CSF contributes to the development of eosinophilia, macrophage granuloma, and fibrosis are discussed in conjunction with the recent findings from us and others.

Animals↗
PubMed1996

Adenoviral gene transfer of macrophage inflammatory protein-2 in rat lung.

Replication-defective adenoviral vectors are capable of localized transfer and expression of incorporated gene product in lung tissue. We have constructed an adenoviral vector that expresses rat macrophage inflammatory protein (MIP)-2, a C-X-C chemokine specifically chemotactic for neutrophils, Supernatants from 293 cells, infected with the adenoviral MIP-2 (ADMIP-2) construct, showed potent chemotactic activity and the ability of the ADMIP-2 vector to transcribe and make functional protein was confirmed. In vivo analysis of bronchoalveolar lavage fluid from rats after intratracheal instillation of ADMIP-2 (10(9) plaque-forming units) showed a 10-fold increase in the absolute number of neutrophils in bronchoalveolar lavage fluid as opposed to rats treated with an equal titer of an E1-disabled control virus expressing firefly luciferase (ADCA-18). Neutrophils constituted 65% of total BAL cells with alveolar macrophages being the other major cell type recovered. Rat MIP-2 protein was increased (nanograms per milliliter) in bronchoalveolar lavage fluid over a period of 7 days in ADMIP-2-treated animals. MIP-2 mRNA was demonstrated by Northern blot analysis in lung tissue, and histological analysis confirmed the presence of massive localized tissue neutrophilia. Evidence of chronic tissue injury and repair (ie, fibrosis) was not detected up to 2 weeks after the neutrophil infiltrate had resolved, subsequent to decreased chemokine presence. Adenoviral gene transfer proved an effective tool for the assessment of lung tissue expression of this chemokine in vivo and is useful in developing rodent models of tissue neutrophilia.

Adenoviridae↗
PubMed1996

Searching eye movement, smooth pursuit eye movement and schizophrenia.

OBJECTIVE: To detect whether the smooth pursuit eye movement (SPEM) and searching eye movement (SEM) could be considered as a biological marker of schizophrenia, and used as a tool in helping diagnosis of schizophrenia. METHODS: 88 schizophrenics, 77 patients with mood disorders, 32 with "neurosis", and 74 normal healthy controls were examined for SPEM and SEM individually. The authors verified the results in all the first-visit 150 outpatients in March 1993 by comparing the examination results with the clinical diagnoses after a 6-month follow-up. RESULTS: Significant differences were found in the number of eye fixation (NEF) and total eye scanning length (TESL) of SEM between schizophrenics and normal controls or patients with other disorders. Less NEF and shorter TESL could be helpful in differential diagnosis, and the agreement rate, Kappa coefficient was 0.62. No significant differences were found in SPEM in this investigation between non-medicated schizophrenics and normal controls. CONCLUSION: Searching eye movement (SEM) might be considered as a biological marker of schizophrenia and might be used as a supplementary tool in its diagnosis.

Adult↗
PubMed1996

[A study of CD23 expression and regulation in the patients with asthma].

To study the pathogenesis of asthma, we examined the CD23 expression on peripheral blood mononuclear cells (PBMC) from 25 healthy donors and 28 asthmatic patients with APAAP test. The results demonstrated that CD23 antigen expressed strongly on PBMC from patients and their PBMC correlated positively with their IgE level (r = 0.78 P < 0.01). We investigated the regulation of CD23 expression by IL-4 and IFN-gamma in vitro, the results demonstrated that IFN-gamma could inhibit spontaneous and IL-4 induced expression of CD23. It was suggested that the analysis of the percentage of positive CD23 expression is useful for making diagnosis and assessing severity of asthma and is of significance in elucidating the pathogenesis of the asthma.

Adult↗
PubMed1996

[A study on using rIL-4 and IFN-gamma to regulate IgE synthesis in bronchial asthma patients in vitro].

OBJECTIVE: In order to elucidate the cytokines responsible for altered IgE producing in patients with asthma. METHODS: The in vitro effects of recombinant interleukin-4 (rIL-4) and interferon-gamma (IFN-gamma) on synthesis of IgE by peripheral blood mononuclear cell (PBMC) were studied. RESULTS: Spontaneous IgE synthesis by PBMC was significantly increased in patients with asthma compared with the controls (t = 4. 4712, P < 0.001). Although the maximum amounts of IgE synthesis using PBMC after stimulation with rIL-4 were almost the same both in patients with asthma and in controls (t = 0.0620, P > 0.05), the enhancement rate of rIL-4-induced IgE synthesis was lower in asthma tic patients than in the controls (t = 4. 6719, P < 0.005). IFN-gamma suppressed not only spontaneous but also rIL-4-induced IgE synthesis by PBMC in asthmatic patients. The suppressive effect on IgE synthesis was more prominent in patients with asthma than in the controls (t = 7.1833, P < 0.001). CONCLUSIONS: These results suggest that asthma attacks are related to IgE- dependent trigger mechanism; the imbalance of Il-4 and IFN-gamma in vivo is involved in the development of asthma.

Adult↗
PubMed1995

Adenovirus vectors for cytokine gene expression.

Recombinant Adenovirus type 5 constructs containing IL-6 cDNA can be used to infect cells in vitro and obtain a high level of IL-6 expression and secretion into culture media. Furthermore, Ad5-IL-6 viruses can also be used to infect Balb/c mice or Sprague-Dawley rats and obtain a high level of IL-6 expression that is sustained over a period of 3-5 days. Intratracheal infection was accompanied by dramatic increases in virus-encoded IL-6 mRNA levels in rat lung tissue, raised levels of IL-6 detected in bronchoalveolar lavage fluids and in serum, and IL-6-dependent sequelae such as liver acute phase responses. This occurs in a tissue-specific manner, depending on routes of infection by the virus. Rat lungs showed a prominent expansion (10 fold in numbers) of all classes of lymphocytes, including B cells, T helper cells (CD4+) and CTL (CD8+) at day 7 after infection which resolved significantly by day 12. Thus the associated biological effects of viral vector mediated IL-6 over-expression was also transient in nature. Other tissues can be infected with Ad5 and thus can also be induced to express selected genes in a transient fashion. We are currently examining the potential for Ad recombinant cytokine vectors in therapy for cancer and for bone marrow reconstitution after transplantation. Thus the use of recombinant Ad5 vectors may have a broad application in the study of cytokine function and possibly in future therapy as a transient gene transfer approach.

Adenoviruses, Human↗
PubMed1995

Antiviral activity of RNA molecules containing self-releasing ribozymes targeted to lymphocytic choriomeningitis virus.

Ribozymes catalytically cleave substrate RNA molecules in a sequence-specific manner. Engineered ribozymes can be developed and introduced into tissue culture cells to regulate gene expression and to inhibit viral replication. We have previously reported on the construction of cell lines that constitutively express a single antiviral ribozyme embedded in a lengthy RNA transcript. These cells exhibited a marked reduction in their ability to support viral infection. Here we report the construction of RNA molecules that contain one or two antiviral ribozymes, each specific for a different cleavage site on the genome of the target virus, lymphocytic choriomeningitis virus (LCMV), and each contained in a self-cleavage cassette comprising cis-acting ribozymes designed to release the antiviral molecules from the transcript. In vitro studies showed that both antiviral ribozymes were released properly from the RNAs following cleavage by the flanking ribozymes and that these released ribozymes functioned as expected in cleaving the target virus RNA. These self-cleaving cassettes have been clones into a retroviral vector downstream of, but in the same transcript as, the chloramphenicol acetyltransferase (CAT) gene. Thus, we hoped to employ CAT as a surrogate marker of ribozyme transcription. Stably transformed cell lines were established. Cleavage by the cis-acting ribozymes was incomplete, as assessed by Northern blot analysis and by the ability of transformed cells to produce infectious retroviral particles. Nevertheless, the antiviral ribozyme sequences exerted effects in tissue culture. LCMV RNA levels in ribozyme-expressing cells were suppressed, and infectious virus yields were decreased by up to 95% compared with normal cells and with cells expressing inverted ribozymes. The antiviral effects correlated with CAT levels, but there was no significant difference between cell lines expressing a single ribozymes and those expressing two.

3T3 Cells↗
PubMed1995

Macrophage engulfment of apoptotic neutrophils contributes to the resolution of acute pulmonary inflammation in vivo.

For resolution of inflammation to occur, it is necessary both to limit leukocyte influx and to clear now redundant cells from the tissues. Recent evidence from in vitro studies suggests that clearance may be an active process, accomplished in part by macrophage engulfment of intact cells that have undergone programmed cell death or apoptosis. However, the kinetics of these events and their association with the resolution of acute inflammatory responses in vivo remain to be elucidated. To investigate these events, we examined an animal model of acute, limited, neutrophilic pulmonary inflammation. Cells were obtained by bronchoalveolar lavage (BAL) of rats at various time points after intratracheal administration of lipopolysaccharide (LPS). Apoptotic neutrophils were rarely seen in BAL from control animals but were detected after neutrophil influx had occurred in response to LPS challenge. Macrophage engulfment of these cells was identified at light microscopy and confirmed at electron microscopy. The proportion of macrophages that had engulfed apoptotic neutrophils was maximal 24 h after LPS challenge and declined thereafter as total neutrophil numbers fell. During the resolution phase, the alveolar macrophages became positive for peroxidase, indicating the presence of neutrophil granule contents in their cytoplasm. These observations demonstrate that apoptosis of leukocytes indeed occurs during the course of an acute inflammatory response in vivo and that the emergence of apoptotic neutrophils and macrophage engulfment of these cells are temporally correlated with the resolution of acute inflammation.

Animals↗
PubMed1995

[The cytotoxicity of malignant pleural effusion lymphocytes and LAK cells against autologous tumor cells].

In malignant pleural effusion, lymphocytes (MPEL) and autologous tumor cells (ATC) were obtained by centrifugation on discontinuous density gradients from 16 patients with malignant pleural effusion. The cytotoxicity of MPEL against ATC were compared with that of peripheral blood lymphocytes (PBL). It was demonstrated that the results for separation with 100%: 60% Ficoll-Hypaque which formed a discontinuous density gradients were the best in three sets of discontinuous density gradients. The cytotoxicity of PBL was higher than that of MPEL (P < 0.001), but the cytotoxicity and expansion of MPEL-activated by rIL2 was much higher than that of PBL-activated by rIL2 (LAK cells) (P < 0.001). This shows that local immune reaction within pleural cavity of patients with malignant pleural effusion was in the state of suppression, but the state could be improved by using rIL2. Therefore, we consider that MPEL could be the better effector cells than LAK cells in tumor adoptive immunotherapy.

Adult↗