CHI3L1 and CHI3L2 overexpression in motor cortex and spinal cord of sALS patients

BACKGROUND

Amyotrophic Lateral Sclerosis (ALS) is a rapidly progressive neurodegenerative disease characterized by the degeneration and death of upper (UMN) and lower (LMN) motor neurons. In the last decade, it has been shown that Chitinases are an important prognostic indicator of neuro-inflammatory damage induced by microglia and astrocytes.

MATERIALS AND METHODS

We analyzed microarray datasets obtained from the Array Express in order to verify the expression levels of CHI3L1 and CHI3L2 in motor cortex biopsies of sALS patients with different survival times. We also divided the sALS patients into smokers and non-smokers. In order to extend our analysis, we explored two additional microarray datasets, GSE833 and GSE26927, of post-mortem spinal cord biopsies from sALS patients.

RESULTS

The analysis showed that CHI3L1 and CHI3L2 expression levels were significantly upregulated in the motor cortex of sALS patients, compared to the healthy controls. Moreover, their expression levels were negatively correlated with survival time. Interesting results were obtained when we compared the expression levels of Chitinases among smokers. We showed that CHI3L1 and CHI3L2 were significantly upregulated in sALS smokers compared to non-smokers. Furthermore, we found that four genes belonging to the Chitinases network (SERPINA3, C1s, RRAD, HLA-DQA1) were significantly upregulated in the motor cortex of sALS patients and positively correlated with Chitinases expression levels. Similar results were obtained during the exploration of the two-microarray dataset.

CONCLUSIONS

This study suggests that CHI3L1 and CHI3L2 are associated with the progression of neurodegeneration in motor cortex and spinal cord of sALS patients.

OAS Gene Family Expression Is Associated with HIV-Related Neurocognitive Disorders

HIV-associated neurocognitive disorders are common in HIV-infected individuals, even in the combination antiretroviral therapy (c-ART) era. Several mechanisms are involved in neuronal damage, including chronic inflammation immune activation. Mammalian 2'-5'-oligoadenylate synthetase (OAS) genes are produced in response to interferon (IFN), mainly by monocytes, and exert their antiviral functions by activation of RNase L that degrades viral and cellular RNAs. In this study, we aimed at exploring OAS gene family RNA expression in simian immunodeficiency virus encephalitis (SIVE), in HIV-associated neurocognitive disorders (HAND), and in HIV-associate dementia (HAD). We analyzed three microarray datasets obtained from the NCBI in order to assess the expression levels of OAS gene family network in brain biopsies of macaques with SIVE vs uninfected animals, as well as post-mortem brain of individuals with HAND (on or off ART) vs uninfected controls and three brain regions of HIV-infected individuals with both neurocognitive impairment (HAD) and encephalitis (HIVE). All OAS genes were upregulated both in SIVE and in HAND. OAS expression was significantly higher in high-viremic individuals; increased expression levels persisted in cART subjects when compared to healthy controls. OAS gene network analysis showed that several genes belonging to the type I IFN pathway, especially CXCL10 and IFIT3, were similarly upregulated in SIVE/HAND. Furthermore, we identified a significant upregulation of OAS gene family RNA expression in basal ganglia, white matter, and frontal cortex of HIV-1, HAD, and HAD/HIVE patients compared to healthy subjects. OAS gene family expression is increased in brain sections from individuals with HAND, HAD, and HIVE as well as macaques with SIVE. OAS family expression is likely to be induced by IFN as a consequence of viral replication in the CNS. Its long-term upregulation may contribute to the chronic inflammatory status and neurocognitive impairment we still observe in virologically suppressed individuals on c-ART.

Vitamin D3 regulates LAMP3 expression in monocyte derived dendritic cells

The family of lysosome-associated membrane proteins (LAMPs) encompassing LAMP1, LAMP2 and DC-LAMP (LAMP3) are the major constituents of the glycoconjugates coat present on the inside of the lysosomal membrane. LAMP3 is highly expressed only in certain cell types and during the differentiation stages. Its expression is linked the maturation of dendritic cells, inflammation, poor prognosis of certain tumors, and the locus where it is encoded was identified as a risk factor for Parkinson's disease (PD). Here, we investigated the capacity of Vitamin D3 to modulate the expression of LAMP3 during the dendritic cells differentiation and maturation. Our results demonstrated that the Vitamin D3 reduce the LAMP3 mRNA/protein expression during the dendritic cells differentiation and maturation, via NFκB pathways. Furthermore, we demonstrated that the Vitamin D3 was able to modulate the expression of LAMP3 likewise to in vitro tolerogenic dendritic cells. In summary, these data showed that the decrease of LAMP3 expression by Vitamin D3could enhance the tolerogenic characteristic of dendritic cells.

Vitamin D3 inhibits TNFα-induced latent HIV reactivation in J-LAT cells

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) is known to suppress NF-kB activity by interfering with its pathways. The aim of this study was to investigate the ability of 1,25(OH)2D3 in reducing the reactivation of the HIV virus J-LAT cells, an established model of latently infected cells, which were treated with TNFalpha (100 ng/ml) for 2 h with or without 24 h 1,25(OH)2D3 (100 nM) pretreatment. Reactivation of HIV RNA in J-LAT was evaluated in terms of green fluorescent protein (GFP) expression. The same experimental setting was repeated on T cells from HIV-infected patients. Treatment with TNFalpha was associated with a 16 % increase in GFP+ cells and a five-fold increase in unspliced HIV RNA expression (p < 0.04). Pretreatment of J-LAT cells with 1,25(OH)2D3 for 24 h followed by TNFalpha (100 ng/ml) for 2 h reduced the percentage of GFP+ cells by 8 %; moreover, a 2.4-fold decrease in unspliced HIV RNA expression was observed (p < 0.002). In T cells from patients, treatment with TNFalpha significantly increased unspliced HIV RNA expression (sixfold increase, p < 0.02), whereas prestimulation with 1,25(OH)2D3 reduced its expression (2.5-fold decrease, p < 0.02) compared to controls.1,25(OH)2D3 is able to reduce the ability of TNFalpha to upregulate the transcription of HIV RNA from latently infected cells. These data provide further understanding of the pathogenic mechanisms regulating viral reactivation from latent reservoirs, along with new insight in viral internalization.

CD4+ T-cell gene expression of healthy donors, HIV-1 and elite controllers: Immunological chaos

OBJECTIVES

T-cell repertoire dysfunction characterizes human immunodeficiency virus type 1 (HIV-1) infection, but the pathogenic mechanisms remain unclear. Disease progression is probably due to a profound dysregulation of Th1, Th2, Th17 and Treg patterns. The aim of this study was to analyze the features of CD4+ T cells in HIV-positive patients with different viroimmunological profile.

METHODS

we used a gene expression dataset of CD4+ T cells from healthy donors, HIV+ naive patients and Elite Controllers (EC), obtained from the NCBI Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/, accession number GSE18233).

RESULTS

Principal Component Analysis (PCA) showed an almost complete overlap between the HIV-infected and EC patients, which cannot easily explain the different responses to HIV infection of these two group of patients. We have found that HIV patients and the EC showed an upregulation of the Th1 pro-inflammatory cytokines and chemokines, compared to the controls. Also, we have surprisingly identified IL28B, which resulted downregulated in HIV and EC compared to healthy controls. We focused attention also on genes involved in the constitution of the immunological synapse and we showed that HLA class I and II genes resulted significantly upregulated in HIV and in EC compared to the control. In addition to it, we have found the upregulation of others syncytial molecules, including LAG3, CTLA4, CD28 and CD3, assisting the formation of syncytia with APC cells.

CONCLUSIONS

Understanding the mechanisms of HIV-associated immunological chaos is critical to strategically plan focused interventions.

Induction of OAS gene family in HIV monocyte infected patients with high and low viral load

BACKGROUND

The innate immunity plays a predominant role in the early control of HIV infection, before the induction of adaptive immune responses. The cytokine secretion operated by the CD4(+) T helper cells is able to induce a response in the innate immunity cells and significantly affect HIV-1 persistence and replication. One of the pathways activated by monocytes to restrain viral infection is the 2' -5' -oligoadenylate synthetase (OAS)/RNase L pathway. OAS is activated by dsRNA and IFNs to produce 2' -5' oligoadenylates, which are activators of RNase L. This enzyme degrades viral and cellular RNAs, thus restricting viral infection.

MATERIALS AND METHODS

We analyzed a microarray dataset obtained from the NCBI Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/) databank (accession number GSE18464) in order to verify the modulation of the OAS gene family in CD14 (+) monocytes isolated from 55 subjects, 22 with HIV-1 HVL (high viral load), and 22 with HIV-1 LVL (low viral load), as well as in 11 HIV-1 seronegative controls. We have validated the data on the expression levels of the OAS genes by performing real-time PCR on monocyte from a cohort of HIV infected patients (n = 20), with clinical characteristics similar to those of the patients recruited in the study present in the microarray.

RESULTS

Microarray analysis showed that OAS gene family are significantly upregulated in monocyte of HIV-1 patients with HVL, as compared to LVL patients and to healthy donors. Furthermore, we showed a significant correlation between the OAS gene family and the log2 viral load and CD4 count. These results were confirmed by the in vitro validation.

CONCLUSIONS

Data from this study suggest an involvement for the OAS gene family in the control of HIV-1 infection.

Expression of CHI3L1 and CHIT1 in osteoarthritic rat cartilage model. A morphological study

Osteoarthritis is a degenerative joint disease, which affects millions of people around the world. It occurs when the protective cartilage at the end of bones wears over time, leading to loss of flexibility of the joint, pain and stiffness. The cause of osteoarthritis is unknown, but its development is associated with different factors, such as metabolic, genetic, mechanical and inflammatory ones. In recent years the biological role of chitinases has been studied in relation to different inflammatory diseases and more in particular the elevated levels of human cartilage glycoprotein 39 (CHI3L1) and chitotriosidase (CHIT1) have been reported in a variety of diseases including chronic inflammation and degenerative disorders. The aim of this study was to investigate, by immunohistochemistry, the distribution of CHI3L1 and CHIT1 in osteoarthritic and normal rat articular cartilage, to discover their potential role in the development of this disease. The hypothesis was that the expression of chitinases could increase in OA disease. Immunohistochemical analysis showed that CHI3L1 and CHIT1 staining was very strong in osteoarthritic cartilage, especially in the superficial areas of the cartilage most exposed to mechanical load, while it was weak or absent in normal cartilage. These findings suggest that these two chitinases could be functionally associated with the development of osteoarthritis and could be used as markers, so in the future they could have a role in the daily clinical practice to stage the severity of the disease. However, the longer-term in vivoand in vitro studies are needed to understand the exact mechanism of these molecules, their receptors and activities on cartilage tissue.

Elevated chromogranin A serum levels in ovarian carcinoma patients

Background: The observation of neuroendocrine activity during clinical course of ovarian cancer, suggested the use of neuroendocrine serum markers to detect this tumor. Aim: To evaluate the usefulness of serum measurements of chromogranin A (CgA) in the various stages of ovarian cancer. Materials and Methods: We measured serum concentrations of CgA and cancer antigen 125 (CA125) in 79 women at different clinical stages of ovarian cancer, enrolled between 2000 and 2007, and in a control group of 50 female volunteers. Results: CgA showed increased levels in patients with ovarian cancer as compared with healthy subjects, as it has been seen for CA125 serum levels. We also observed significant increase in CgA and CA125 serum levels when comparing patients with ovarian cancer in stage I versus stage II (P < 0.001); stage I versus stage III (P < 0.001); stage I versus stage IV (P < 0.001); stage II versus stage III (P < 0.001); stage II versus stage IV (P < 0.001). In patients with ovarian carcinoma in stage IV we observed a correlation between CgA and CA125 with a difference of 0.718 (P < 0.001). Conclusions: CgA serum levels were elevated in ovarian cancer and increased with the stage. Further studies are needed to elucidate the role of CgA as a prognostic indicator during treatment for ovarian cancer.

Immuno-modulatory effects of vitamin D3 in human monocyte and macrophages

Vitamin D3 [1α,25-(OH)(2)D(3)], involved in the regulation of body calcium homeostasis, promotes immature myeloid precursor cells differentiation into monocytes/macrophages. In this study we compared the regulatory interaction between 1α,25-(OH)(2)D(3) and tumor necrosis factor (TNF)-α or lipopolysaccharide (LPS) in the mRNA expression of interleukin (IL)-1β, (IL)-6, TNF-α, toll like receptors (TLR)-2 and (TLR)-4 in freshly isolated human monocyte (MonoT0) and in macrophages cultured for seven days (MØT7). Additionally, we detected the effect of 1α,25-(OH)(2)D(3) on macrophages chemotaxis. The expression of IL-1β, IL-6 and TNF-α, as well as TLR-2 and TLR-4 in MonoT0 and in MØT7 was examined by real time RT-PCR. Macrophages chemotaxis was analyzed by using horizontal chemotaxis agarose spot assay. We found that 1α,25-(OH)(2)D(3) influences macrophages chemotaxis and differently modulates the expression of IL-1β, IL-6, TNF-α and TLRs in the two different stages of monocytes/macrophage maturation. In conclusion our data add new information about the role of 1α,25-(OH)(2)D(3) on the expression of inflammatory mediators in human monocyte/macrophages, underlying the complex function of these cells. Investigating the differences in the pattern of expression of immune-mediators produced by MonoT0 and MØT7 may provide a new way to examine their biochemical and molecular function and may constitute a model system with well-defined behavior with respect to early or tardive events in the innate immune response.

Non-AIDS-defining cancers among HIV-infected people

The natural history of HIV infection has been greatly changed by the introduction of highly active antiretroviral therapy (HAART). As a consequence of improved immune function, the incidence of AIDS-defining cancers (ADCs), such as Kaposi's sarcoma, non-Hodgkin's lymphoma (NHL) and invasive cervical cancer, has significantly declined. On the contrary, non-AIDS-defining cancers (NADCs), such as hepatocellular carcinoma, anal cancer, lung cancer, colorectal cancer and Hodgkin's lymphoma, have gradually emerged as a major fraction of the overall cancer burden. The reasons are still partially unknown. Some of the increased risk may be explained by a high prevalence of cancer risk factors, such as smoking, alcohol consumption, human papilloma virus (HPV) infection and HCV infection among HIV-infected people. The role of immunosuppression in the development of NADCs is controversial, as several studies have not found a clear-cut evidence of an association between the degree of immunosuppression and the development of NADCs. Analogously, the impact of HAART is still not well defined. Future research should focus on the etiology of NADCs, in order to shed light on the pathogenesis of cancer and ultimately to work for prevention; moreover, additional studies should evaluate the best therapeutic approaches to NADCs and the impact of cancer screening interventions among HIV-infected people, in an effort to diagnose cancer at an earlier stage.

Variable effects of cyclophosphamide in rodent models of experimental allergic encephalomyelitis

In this study, we have evaluated the effects of cyclophosphamide on the development of experimental allergic encephalomyelitis (EAE) in four EAE rodent models: monophasic EAE in Lewis rats, protracted relapsing (PR)-EAE in DA rats, myelin oligodendrocyte protein (MOG)-induced EAE in C57Bl/6 mice and proteolipid protein (PLP)-induced EAE in Swiss/Jackson Laboratory (SJL) mice. Cyclophosphamide, administered either prophylactically or therapeutically, suppressed most strongly the clinical symptoms of PR-EAE in DA rats. Treated rats in this group also exhibited the lowest degree of inflammatory infiltration of the spinal cord, as well as the lowest levels of nuclear factor kappa B, interleukin-12 and interferon-gamma. Cyclophosphamide prophylactically, but not therapeutically, also delayed significantly the onset of EAE in Lewis rats. In contrast, regardless of the treatment regimen used, was unable to influence the clinical course of EAE in either MOG-induced EAE in C57Bl/6 mice or PLP-induced EAE in SJL mice. This heterogeneous pharmacological response to cyclophosphamide suggests that significant immunopathogenic differences exist among these EAE rodent models that must be considered when designing preclinical studies. In addition, the effectiveness of cyclophosphamide in dark Agouti (DA) rats with PR-EAE suggests that this may be a particularly useful model for studying novel therapeutic approaches for refractory and rapidly worsening multiple sclerosis in human patients.

Chitotriosidase: the yin and yang

The enzyme chitotriosidase (ChT), the human analogue of chitinases from non-vertebrate species, is one of the most abundant and indicative proteins secreted by activated macrophages. Its enzymatic activity is elevated in serum of patients suffering from Gaucher's disease type 1 and in some other inherited lysosomal storage disorders, as well as in diseases in which macrophages are activated. The last decade has witnessed the appearance of a substantial number of studies attempting to unravel its cellular functions, which have yet not been fully defined. A great deal of progress has been made in the study of the physiological roles of ChT. This review is looks at the key areas of investigations addressed to further illuminate whether ChT activation might have different functional meanings in various diseases.

Chitotriosidase gene expression in Kupffer cells from patients with non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic steatohepatitis (NASH) is a clinicopathological condition characterised by a necroinflammatory disorder with fatty infiltration of the hepatocytes. The molecular mechanisms involved in the anomalous behaviour of liver cells have only partially been determined. Human chitotriosidase (Chit) is a chitinolytic enzyme mainly produced by activated macrophages. The aim of this study was to investigate the expression of the chitinase-like gene in Kupffer cells, to determine how chitotriosidase may be implicated in the progression from uncomplicated steatosis to steatohepatitis with progressive fibrosis.

METHODS

75 subjects were studied: 40 with NASH, 20 with simple steatosis, and 15 normal controls. Kupffer cells obtained from liver biopsies were used to detect CHIT expression, superoxide anion (O2-), lipid peroxidation, and tumour necrosis factor alpha (TNFalpha) and ferritin levels.

RESULTS

CHIT expression differed markedly in livers from normal controls and in those from patients with simple steatosis or non-alcoholic steatohepatitis. A significant correlation between mRNA CHIT and O2-, lipid peroxidation, TNFalpha, and ferritin levels was observed in both NASH and simple steatosis.

CONCLUSIONS

Human Kupffer cells in NASH patients overproduce chitotriosidase. At the highest levels of production, this enzyme may play a role in increasing the risk for a poor outcome in steatohepatitis.

Interferon-gamma, tumor necrosis factor-alpha, and lipopolysaccharide promote chitotriosidase gene expression in human macrophages

Human chitotriosidase (Chit), a chitinolytic enzyme, is a member of the chitinase family. In human plasma, Chit activity has been proposed as a biochemical marker of macrophage activation in several lysosomal diseases. Recently we found that Chit activity is higher in patients affected by Plasmodium falciparum malaria infection, suggesting that Chit may reflect induction of an immunological response. To assess this hypothesis, we evaluated the CHIT1 mRNA levels in human monocytes/macrophages (HMMs) following treatment with interferon-gamma (IFNgamma), tumor necrosis factor-alpha (TNFalpha), and lipopolysaccharide (LPS). Stimulation of macrophages with INF-gamma, TNF-alpha, and LPS resulted in an increase in Chit activity as well as the levels of CHIT1 mRNA as measured by quantitative real-time PCR. The data presented in this article show that Chit plays a role in the response to the activation of INF-gamma-, TNF-alpha-, and LPS-driven macrophages, suggesting that the production of Chit by macrophages could have biological relevance in the immune-response.

Action of prolactin, IFN-γ, TNF-α and LPS on heme oxygenase-1 expression and VEGF release in human monocytes/macrophages

The pituitary hormone prolactin (PRL) has recently been regarded as a local regulator of macrophage responses. Our goal in this study was to investigate the regulatory interaction between PRL, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS) in the heme oxygenase-1 (HO-1) expression and the vascular endothelial growth factor (VEGF) production in human monocytes/macrophages (HMMs). In vitro treatment of HMMs with PRL, IFN-gamma, TNF-alpha and LPS was found to increase both HO-1 expression and protein synthesis in a time-dependent manner. HMMs treated with PRL, IFN-gamma, TNF-alpha and LPS also showed an enhanced release of VEGF. Moreover, co-stimulation of PRL with LPS caused activation of HMMs functions, enhancement of HO-1 expression and induction of VEGF release, whereas addition of PRL inhibited up-regulation of HO-1 or VEGF induced by IFN-gamma or TNF-alpha. Our results demonstrate that PRL, IFN-gamma, TNF-alpha and LPS modulate the expression of angiogenic factors providing additional information about the regulatory mechanism, which controls the angiogenic function of macrophages.

Prolactin induces chitotriosidase gene expression in human monocyte-derived macrophages

Human chitotriosidase (Chit), a chitinolytic enzyme, is a member of the chitinase family. In human's plasma Chit activity have been proposed as a biochemical marker of macrophage activation in several lysosomal diseases. Recently we found that Chit activity is higher in patients affected by Plasmodium falciparum malaria infection suggesting that chitotriosidase may induce an immunological response. The pituitary hormone prolactin (PRL) is a multifunctional polypeptide also produced by immune cells and represents a key component of the neuroendocrine-immune loop. The presence of PRL receptors in macrophage suggests that PRL is involved in regulating functions in these cells. Our objective in this study was to investigate the effect of PRL in human monocyte-derived macrophages (HMMs) on Chit production. Administration of PRL in HMMs was found to increase both expression and activity of Chit in a time and dose dependent manner as quantified, respectively, by real time PCR and Chit activity assay. PRL-treated monocyte-derived macrophages showed also an enhanced release of superoxide anion (O2-) release. Our observations confirm that PRL regulates HMMs activation and suggest, for the first time, that it influences immune function also through the induction of Chit activity.

A 24-bp duplication in exon 10 of human chitotriosidase gene from the sub-Saharan to the Mediterranean area: role of parasitic diseases and environmental conditions

Human chitotriosidase (Chit) is a member of the chitinase family and it is synthesized by activated macrophages. Recently, a genetic polymorphism was found to be responsible for the common deficiency in Chit activity, frequently encountered in different populations. We analyzed the Chit gene in some ethnic groups from the Mediterranean and African areas, to evaluate whether the Chit gene polymorphism correlates with the changes in environmental features and the disappearance of parasitic diseases. We found a heterozygote frequency for the duplication of 24 bp in exon 10 of 44% in Sicily and 32.71% in Sardinia, whereas those homozygous Chit deficient were 5.45 and 3.73%, respectively. In contrast, in Benin and Burkina Faso, both mesoendemic regions for Plasmodium falciparum malaria and other infections due to intestinal parasites, a low incidence of Chit mutation was found (heterozygous 0 and 2%, respectively) and no subject was homozygous for Chit deficiency. Our results provide evidence of the fact that the low frequency or the absence of mutant Chit gene may represent a protective factor in the population still living in disadvantaged environmental conditions. The present study suggests that the disappearance of parasitic diseases and the improved environmental conditions may have ensued the occurrence of a high percentage of 24-bp mutation in Sicily, in Sardinia and in other Mediterranean countries, whereas in the sub-Saharan regions (Benin and Burkina Faso), the widespread parasitic diseases and the poor social status have contributed to maintenance of the wild-type Chit gene.

Cell death in human acute myelogenous leukemic cells induced by pyrrolidinedithiocarbamate

Pyrrolidinedithiocarbamate (PDTC) is a metal chelating compound, which exerts both pro-apoptotic effect and pro-oxidant activity on many cells. Our objective was to investigate whether PDTC was able to interfere with apoptotic process in leukemic and normal bone marrow CD34+ cells. Since hematopoietic growth factors stimulate growth and differentiation and prevent apoptosis, we therefore studied the effect of growth factors pretreatment, such as interleukin-3 and granulocyte-macrophage colony stimulating factor, in human myeloid CD34+ cells to evaluate whether they protect the cells from the apoptotic action of PDTC. We revealed that PDTC exerted an apoptotic effect in leukemic CD34+ cells. This effect was dependent on the ability of this compound to generate the oxidation of cellular glutathion to its disulphide and consequently to induce an intracellular oxidative stress. Hematopoietic growth factors did not protect cells from apoptosis induced by previous treatment with PDTC. The ability of PDTC to induce apoptosis was restricted to acute myelogenous leukaemia CD34+ cells, since normal CD34+cells were insensitive to the pro-oxidant effect of PDTC. These findings imply that normal cells are equipped with mechanisms by which they respond differently to PDTC effects with respect to leukemic cells.

Prolactin increases HO-1 expression and induces VEGF production in human macrophages

The pituitary hormone prolactin (PRL) is a multifunctional polypeptide which exerts a role on cell proliferation and may also contribute to cell differentiation. PRL is also produced by immune cells and is regarded as a key component of the neuroendocrine-immune loop and as a local regulator of macrophage response. The involvement of PRL in regulating monocyte/macrophage functions is suggested by the presence of PRL receptors in these cells. It has been shown that PRL possess both angiogenic and antiangiogenic effects. Recently, we revealed that augmentation of HO-1 activity enhances PRL-mediated angiogenesis in human endothelial cells. Since macrophages are key participants in angiogenesis our objective was to investigate the effect of PRL also in human macrophages. In vitro treatment of macrophages with PRL was found to increase both heme oxygenase-1 (HO-1) expression and protein synthesis in a time and dose dependent manner as quantified respectively by reverse-transcriptase real-time polymerase chain reaction and Western blot analysis. PRL-treated macrophages also showed an enhanced release of vascular endothelial growth factor (VEGF) as demonstrated by ELISA assay. Furthermore, to determine whether PRL-induced HO-1 activity was required for VEGF production by macrophages, the effect of PRL on the induction of VEGF was studied in the presence of an inducer stannic chloride (SnCl(2)) and of an inhibitor stannic mesoporphyrin (SnMP) of HO activity. Our observations suggest that PRL may regulate monocyte activation and influences not only immune function but also angiogenesis.

Modulation of immune response in Plasmodium falciparum malaria: role of IL-12, IL-18 and TGF-beta

The interaction between pro- and anti-inflammatory cytokines such as interleukin 12 (IL-12), interleukin 18 (IL-18) and transforming growth factor beta (TGF-beta) plays an important role in malaria pathogenesis and outcome, modulating the immunoresponse in Plasmodium falciparum malaria. In our previous studies, we analyzed the plasmatic levels of IL-12, IL-18 and TGF-beta in 105 African children with different degrees of malaria and we correlated the production of these cytokines with the severity of the disease. The aim of the present study was to analyze with a mathematical model, taking into account all the relationships between these cytokines and the parameter variations involved in malaria pathogenesis that influence the results of each type of treatment or therapeutic protocol on patients at different stages of the disease. A mathematical correlation was demonstrated between the levels of pro-inflammatory and anti-inflammatory cytokines, and from this it was possible to build curves of reference in which each patient was positioned based on IL-12 level. Our data, obtained in patients with mild and severe diseases, demonstrate that the levels of IL-12 represent a reliable parameter to predict the progression of the disease, which may be complemented or modulated by administration of IL-18 and TGF-beta. Our findings provide future implications for an immune therapy against the P. falciparum malaria infection, especially in the early phase of the disease showing that a more aggressive outcome may be due to the lack of a balanced immune response.

Alterations of the lymphocytic set-up in elderly patients with cancer

It is assumed that the increased incidence of neoplastic pathologies with advancing age is correlated with the immunosenescence and with the altered immune-surveillance. The present study was aimed at evaluating the role of the immunocompetent system and immunosenescence in carcinogenesis. A pool of 99 subjects (38 females, 61 males) has been analyzed in three groups as follows. Group A: 51 elderly subjects with cancer (16 females and 35 males, average age 73.7 +/- 7.5 years). Group B: 24 young subjects with cancer (12 females, 12 males, average age 49.5 +/- 10.3 years). Group C: 24 elderly subjects without any clinical evidence of cancer (10 females, 14 males, average age 74.6 +/- 6.3 years). Hemo-chromocytometric analysis and cytofluorimetric typifying have been performed in all subjects. A decrease of T (CD3+)-lymphocytes has been observed in group A, if compared to group B (P < 0.007), and to group C (P < 0.01), The T (CD4+)-lymphocytes were fewer in group A, than in group C (P < 0.004), and also the NK cells showed the same trend (P < 0.002). The numbers of leukocytes and monocytes increased in group A compared to group C (P < 0.01 and P < 0.004, respectively). Red cell numbers, hemoglobin and hematocrit values were lower in group A than in group B (P < 0.03, P < 0.03, P < 0.01, respectively), and also than in group C (P < 0.007, P < 0.001, P < 0.01, respectively), The results demonstrate that the alterations of the immunocompetent cells, particularly of the T-cell pool, may play an important role in the carcinogenesis of the elderly.

Immunosenescence and cancer: a review

The human neoplastic pathologies are age-dependent. The increased occurrence of tumors observed with advancing age may be determined by the accumulation of certain phenomena promoting different phases of neoplastic processes. In these events, important roles can be attributed to mutations of the genome that accumulate during aging and to the immunosenescence. It may be hypothesized that certain tumors controlled by the immune system may become more frequent in the elderly as a consequence of the decreased functionality of this important defense system of the organism. Nevertheless, the problems of the interrelationships between the immunosenescence and tumors are seriously contradictory. Therefore, on the one hand, one has to establish how much the immunodeficit of the elderly patient may be responsible for the neoplastic pathology, while on the other hand, one cannot neglect important environmental and pathophysiological factors in these cases.

Immunosenescence: a review

Aging involves the morphological and functional integrity of all organs, including the cellular and humoral immunological functions. The main alterations can be listed as follows: (i) Thymic involution resulting in the decreased number of lymphoid precursor T- and B-cells. (ii) Reduced proliferative capacity of T-cells; loss of lymphocyte subgroups as a consequence of the shortening of telomeres. (iii) Qualitative deficiency of B-lymphocytes with a reduced response to exogenous antigens. (iv) Compromised activity of the accessory cells, both directly by depressing the chemotactic and phagocytic responses, and indirectly by increasing the prostaglandin production which inhibit the proliferation of T-cells. (v) Alterations in the production and secretion of various cytokines. (vi) Other factors like the general physiological conditions, the nutritional state, psychological habit and various hormone levels.

Ornithine decarboxylase gene expression in Castleman's disease

Castleman's disease (CD) is a rare atypical lymphoproliferative disorder that is clinically and histologically heterogeneous and is associated with the risk of developing malignant lymphoma. Based on pathological findings CD is divided into two types: a localized form and a multicentric form. The clinical course differs in these two forms. We examined the molecular mechanisms that lie between benign and malignant disease, evaluating a possible implication of oncogenes in the pathogenesis. Since deregulated expression of the gene for ornithine decarboxylase (ODC) has been observed in a variety of human malignancies, we compared ODC expression between the localized and multicentric forms. Using northern blot analysis we found that ODC gene expression clearly differs between the localized and multicentric forms. The findings in this report indicate that the variable pattern of ODC gene expression in the different types of CD could be useful for examining the evolution of this disease.

Possible role of the transcription factor interferon regulatory factor 1 (IRF-1) in the regulation of ornithine decarboxylase (ODC) gene expression during IFN gamma macrophage activation

In this report we discuss the role of interferon regulatory factor 1 (IRF-1) in the regulation of ornithine decarboxylase (ODC) transcription during IFN gamma human macrophage activation. We show that a binding sequence for the transcription factor IRF-1 is contained in the first intron of the human ODC gene (from nt +2711 to nt +2722) and we demonstrate that the level of expression of IRF-1 increases in human macrophages and in the human promonocytic cell line, U937, previously differentiated in monocytes/macrophages by phorbol myristate acetate (PMA), after 2 h of IFN gamma stimulation. We also show that the hamster tk-ts13 cell line, stably transfected with the IRF-1 cDNA, over-expresses ODC. In addition, a specific complex was detected, by gel-shift assay after incubating a 20 bp double-stranded oligomer containing the binding sequence for IRF-1 with nuclear proteins extracted from human macrophages and from (PMA-differentiated) U937 cells stimulated with IFN gamma for 2 h.

Regulation of proliferation and cytokine expression of bone marrow fibroblasts: role of c-myb

The c-myb protooncogene plays a major role in regulating the process of in vitro and in vivo hematopoiesis via its activity as transcriptional regulator in hematopoietic progenitor cells. Since the bone marrow microenvironment appears to regulate in vivo hematopoiesis by maintaining the growth of multipotent progenitors via secretion of specific cytokines, we asked whether c-myb is also required for the proliferation of and/or cytokine production by stromal cells that generate fibroblast-like colonies (fibroblast colony-forming units [CFU-F]). Using the reverse transcriptase polymerase chain reaction technique, we detected low levels of c-myb mRNA transcripts in human normal bone marrow fibroblasts. Treatment of these cells with c-myb antisense oligodeoxynucleotides caused downregulation of c-myb expression, decreased in the number of marrow CFU-F colonies (approximately 54% inhibition) and in the cell number within residual colonies (approximately 80%), and downregulation of granulocyte/macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) mRNA expression. Transfection of T98G glioblastoma cells, in which expression of c-myb, GM-CSF, and SCF mRNAs is undetectable or barely detectable, with a plasmid containing a full-length c-myb cDNA under the control of the SV40 promoter induced the expression of biologically active SCF and GM-CSF in these cells. Regulation of GM-CSF expression by c-myb was due in part to transactivation of the GM-CSF promoter. These results indicate that, in addition to regulating hematopoietic cell proliferation, c-myb is also required for proliferation of and cytokines synthesis by bone marrow fibroblasts.

Highly efficient elimination of Philadelphia leukemic cells by exposure to bcr/abl antisense oligodeoxynucleotides combined with mafosfamide

Synthetic oligodeoxynucleotides complementary to the break-point junction of bcr-abl transcripts selectively inhibit the proliferation of Philadelphia-positive leukemic cells, but residual leukemic cells persist in antisense oligodeoxynucleotides-treated cultures. Cyclophosphamide derivatives such as mafosfamide and 4-hydroperoxycyclophosphamide are used at high doses for purging of Philadelphia leukemic cells from marrows but such treatment can be associated with delayed engraftment and prolonged cytopenias. To develop a more effective procedure that might optimize the killing of leukemia cells and the sparing of normal hematopoietic progenitor cells, a 1:1 mixture of Philadelphia leukemic cells and normal bone marrow cells was exposed to a combination of a low dose of mafosfamide and bcr-abl antisense oligodeoxynucleotides and assayed for growth ability in clonogenic assays and in immunodeficient mice. Bcr-abl transcripts were not detected in residual colonies, and cytogenetic analysis of individual colonies revealed a normal karyotype. Normal but not leukemic hematopoietic colonies of human origin were also detected in marrows of immunodeficient mice 1 mo after injection of the treated cells. Our results indicate that a combination of a conventional chemotherapeutic agent and a tumor-specific antisense oligodeoxynucleotide is highly effective in killing leukemic cells and in sparing a much higher number of normal progenitor cells as compared with high-dose mafosfamide treatment. This offers the prospect of a novel and more selective ex vivo treatment of chronic myelogenous leukemia.

Polyamine involvement in functional activation of human macrophages

Polyamines naturally occur in all living beings and play an important role in the regulation of cell proliferation, differentiation, and functional stimulation of terminally differentiated cells. Our studies, using specific inhibitors of polyamine biosynthesis such as alpha-difluoromethylornithine and methylglyoxal-bis[guanylhydrazone] to prevent polyamine accumulation, have indicated that polyamines are associated with functional activation of human macrophages. Both inhibitors diminished the respiratory burst activity of macrophages induced by lipopolysaccharide and interferon gamma. The methylglyoxal-bis]guanylhydrazone] inhibitory effect was concentration-dependent and could be reversed by spermine, which is the final product of polyamine biosynthesis.

AO 1535 inhibits O2- production by human macrophages

AO 1535 is a semisynthetic monoglycosylceramide derived from O-glycosilated sphingosine, with a chemical structure similar to the glycolipids present in many mammalian tissues. In the epidermis monoglycosylceramides contribute to consolidate the structure of cutaneous layers. It has been recently shown that sphingosine and its derivatives are potent inhibitors of Protein kinase C, and block the 'respiratory burst' of phagocitic cells. In macrophages, like in neutrophils, the reactive oxygen intermediates are produced by a membrane associated enzymatic complex, NADPH-oxidase, which is activated by Protein kinase C. This study demonstrates that AO 1535 is able to inhibit the production of reactive oxygen intermediates in human monocytes and macrophages stimulated by phorbol ester and chemotactic tetrapeptide, suggesting a potential clinical application of AO 1535 in the treatment of inflammatory dermatoses.

Inhibitors of polyamine biosynthesis block tumor necrosis factor-induced activation of macrophages

The activation of polyamine biosynthesis, dependent on increased gene expression of ornithine decarboxylase, has been found to play an important role in the control of cell proliferation and differentiation. In this report it has been found that accumulation of ornithine decarboxylase mRNA also follows stimulation of human monocytes/macrophages by tumor necrosis factor. Human recombinant tumor necrosis factor (100 units/ml) also evoked an enhanced respiratory burst of macrophages. The respiratory burst response was inhibited in a dose-dependent manner with difluoromethylornithine, an inhibitor of ornithine decarboxylase, and methylglyoxal-bis(guanylhydrazone), an inhibitor of the formation of spermidine and spermine. The data presented in this paper suggest that polyamines may play a functional role in tumor necrosis factor-driven macrophage activation, and they are discussed in the context of their possible use as inhibitors of polyamine metabolism in tumor chemotherapy.

Growth factor-dependent inhibition of normal hematopoiesis by N-ras antisense oligodeoxynucleotides

To determine whether N-ras expression is required at specific stages of the process of in vitro normal human hematopoiesis, adherent- and T lymphocyte-depleted mononuclear marrow cells (A-T-MNC) or highly purified progenitors (CD34+ cells) were cultured in semisolid medium, under conditions that favor the growth of specific progenitor cell types, after exposure to N-ras sense and antisense oligodeoxynucleotides. N-ras antisense, but not sense, oligodeoxynucleotide treatment of A-T-MNC and CD34+ cells resulted in a significantly decreased number of granulocyte/macrophage colony-forming units (CFU-GM) induced by interleukin 3 (IL-3) or granulocyte/macrophage colony-stimulating factor (GM-CSF) and of macrophage colonies (CFU-M) induced by M-CSF, but not of granulocytic colonies induced with G-CSF or IL-5. However, the same treatment significantly inhibited colony formation induced by each of the above factors in combination with IL-3. Megakaryocytic colony (CFU-Meg) formation from A-T-MNC or CD34+ cells in the presence of IL-6 + IL-3 + erythropoietin (Epo) was also markedly decreased after antisense oligodeoxynucleotide treatment. Erythroid colonies derived from A-T-MNC in the presence of Epo (CFU-E) were not inhibited upon antisense treatment, whereas those arising from A-T-MNC or CD34+ cells in the presence of IL-3 + Epo (BFU-E) were markedly affected. These results are consistent with the hypothesis that distinct signal transduction pathways, involving N-ras or not, are activated by different growth factors in different hematopoietic progenitor cells.

Transcription factor activation and functional stimulation of human monocytes

Activation of expression of genes encoding transcription factors: c-fos and c-jun and formation of AP1 transcriptional complex in human monocytes was investigated. It was found that lipopolysaccharide induced strongly both c-fos and c-jun expression as well as AP1 formation. Interferon gamma activated strongly c-fos and weakly c-jun and AP1. Tumor necrosis factor induced slightly c-fos and had almost no effect on c-jun and AP1. The data suggest that differences in functional responses elicited in monocytes by all three factors may be dependent on different routes on nuclear signalling employed by the factors.

Selective inhibition of leukemia cell proliferation by BCR-ABL antisense oligodeoxynucleotides

To determine the role of the BCR-ABL gene in the proliferation of blast cells of patients with chronic myelogenous leukemia, leukemia blast cells were exposed to synthetic 18-mer oligodeoxynucleotides complementary to two identified BCR-ABL junctions. Leukemia colony formation was suppressed, whereas granulocyte-macrophage colony formation from normal marrow progenitors was unaffected. When equal proportions of normal marrow progenitors and blast cells were mixed, exposed to the oligodeoxynucleotides, and assayed for residual colony formation, the majority of residual cells were normal. These findings demonstrate the requirement for a functional BCR-ABL gene in maintaining the leukemic phenotype and the feasibility of gene-targeted selective killing of neoplastic cells.

Accumulation of ornithine decarboxylase mRNA accompanies activation of human and mouse monocytes/macrophages

Accumulation of ornithine decarboxylase (ODC) mRNA was investigated in human monocytes and mouse peritoneal macrophages. Treatment of both populations of mononuclear phagocytes with bacterial lipopolysaccharide induced a marked and rapid increase in the accumulation of the ODC gene transcript. A similar phenomenon, albeit less pronounced, was also observed following treatment of human monocytes with human recombinant interferon-gamma. These results suggest a role for ODC, and therefore polyamines, in the regulation of mononuclear phagocyte functions.

Induction of protooncogene fos by extracellular signals in primary glial cell cultures

In the present study various extracellular factors, acting through different second messenger systems, were examined for their capacity to increase the level of c-fos mRNA in primary glial cell cultures. In particular EGF, 12-O-tetradecanoylphorbol 13-acetate, the beta-adrenergic agonist isoproterenol, and the glutamate agonists, ibotenic and quisqualic acid, were studied. All the extracellular stimuli tested induced a rapid and transient increase in c-fos mRNA level in glial cell cultures regardless of the signal transduction pathway and the final effect on cell proliferation.