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.

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.

SERPING1 mRNA overexpression in monocytes from HIV+ patients.

OBJECTIVE: The HIV-1 virus activates the complement system, an essential element of the immune system. SERPING1 is a protease inhibitor that disables C1r/C1s in the C1 complex of the classical complement pathway. METHODS: In this paper, we performed an analysis of several microarrays deposited in GEO dataset to demonstrate that SERPING1 mRNA is modulated in CD14+ monocytes from HIV-1-infected individuals. In addition, data were validated on monocytes isolated from seronegative healthy volunteers, treated with IFNs. RESULTS: Our analysis shows that SERPING1 mRNA is overexpressed in monocytes from HIV-1+ patients and the expression levels correlate positively with viral load and negatively with the CD4+ T-cell count. Of note, anti-retroviral therapy is able to reduce the levels of SERPING1 mRNA, ex vivo. In addition, we found that 30% of the SERPING1 genes network is upregulated in monocytes from HIV-1+ patients. Noteworthy, the expression levels of IFITM1-an antiviral molecule belonging to the genes network-correlate positively with SERPING1 expression. Interestingly, the monocytes treatment with IFN-gamma, IFN-beta and IFN-alpha significantly upregulates the SERPING1 mRNA expression levels. CONCLUSIONS: From the outcome of our investigation, it is possible to conclude that SERPING1 and its network serve as important components of the innate immune system to restrict HIV-1 infection.

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.

The chitinases expression is related to Simian Immunodeficiency Virus Encephalitis (SIVE) and in HIV encephalitis (HIVE).

OBJECTIVES: Human Immunodeficiency Virus (HIV) infection can induce neurocognitive complications classified as HIV-associated neurocognitive disorder (HAND). The chitinase family is associated with innate immunity cells and many infectious diseases. METHODS: We analyzed microarray datasets obtained from NCBI in order to verify the expression of chitinase family genes in hippocampus of uninfected rhesus macaques versus those with histopathologic evidence of Simian Immunodeficiency Virus Encephalitis (SIVE). Moreover, we have analysed two human microarray datasets to verify the results obtained in macaques hippocampus affected by SIVE. For these studies, we have also used the open source tools Genome-scale Integrated Analysis of gene Networks in Tissues (GIANT) to identify the chitinase genes network. RESULTS: CHIT1, CHI3L1 and CHI3L2 levels were significantly increased in SIVE hippocampus as compared to non-infected control specimens. Furthermore, we found a negative correlation between CHIA vs. Brain Viral Load (BVL). These data was confirmed partially in human brain section of HAD/HIVE subjects. Also, we showed that HIV-1 was able to modulate the expression of CHIT1, CHI3L1, CHI3L2 and CHID1 in human macrophages. CONCLUSIONS: These results suggest that chitinase gene expression is altered in SIVE and in HAD/HIVE brain sections and call for more studies examining whether this is a protective immunological reaction or a destructive tissue response to encephalitis.

Chitinase expression in Alzheimer's disease and non-demented brains regions.

BACKGROUND: Alzheimer disease is the most typical form of dementia. The causes of AD are not yet completely understood, but they include a combination of genetic, environmental and lifestyle factors that influence ja person's risk for developing the disease. New biomarkers related to these processes could be important for the diagnosis and follow-up of AD patients. OBJECTIVE: The intent of this study was to weigh the expression levels of chitinases genes in brain regions of late-onset AD (LOAD) patients. MATERIALS AND METHODS: We analysed three microarray datasets obtained from the NCBI in order to verify the expression levels of chitinase genes family in brain biopsies (CR, DLPFC and VC) of LOAD patients compared to healthy subjects. We also divided the sample in function of sex difference and ages. RESULTS: The analysis showed that all chitinases genes were modulated in LOAD brain regions compared to healthy subjects. Furthermore positively correlation was identified between chitinases gene expression and healthy age's subjects. Moreover, it has been shown that CHI3L1 and CHI3L2 were regulated differently in healthy and LOAD brain depending on the sex. CONCLUSION: It is possible to conclude that all chitinases could be considered new potential markers for LOAD disease.

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.

Impact of gut microbiota on diabetes mellitus.

Various functions of the gut are regulated by sophisticated interactions among its functional elements, including the gut microbiota. These microorganisms play a crucial role in gastrointestinal mucosa permeability. They control the fermentation and absorption of dietary polysaccharides to produce short-chain fatty acids, which may explain their importance in the regulation of fat accumulation and the subsequent development of obesity-related diseases, suggesting that they are a crucial mediator of obesity and its consequences. In addition, gut bacteria play a crucial role in the host immune system, modulation of inflammatory processes, extraction of energy from the host diet and alterations of human gene expression. Dietary modulation of the human colonic microbiota has been shown to confer a number of health benefits to the host. Simple therapeutic strategies targeted at attenuating the progression of chronic low-grade inflammation and insulin resistance are urgently required to prevent or slow the development of diabetes in susceptible individuals. The main objective of this review is to address the pathogenic association between gut microbiota and diabetes, and to explore any novel related therapeutic targets. New insights into the role of the gut microbiota in diabetes could lead to the development of integrated strategies using probiotics to prevent and treat these metabolic disorders.

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.

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.

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.

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 vivo and in vitro studies are needed to understand the exact mechanism of these molecules, their receptors and activities on cartilage tissue.  

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)-1ß, (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-1ß, 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-1ß, 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.

Altered plasma cytokine levels in Alzheimer's disease: correlation with the disease progression.

Increasing evidence supports a propensity towards inflammation in Alzheimer's disease (AD) pathogenesis. In our previous studies we observed high levels of IL-16, IL-18 and TGF-beta1 mRNA expression in monocyte-macrophages of the peripheral blood of AD patients. The aim of this investigation was to determine the plasma levels of IL-12, IL-16, IL-18 and TGF-beta1 in AD patients at different stages of the disease and to correlate the production of these cytokines with the disease progression. The levels of IL-12, IL-16, IL-18 and TGF-beta1 resulted higher in AD-mild patients, were slightly lower in AD-moderate patients, whereas no significant difference was observed between AD-severe patients and non-demented age-matched subjects. The correlation values between cytokine plasma levels were dependent on the disease progression. Our data indicate that plasma levels of these inflammatory molecules follow the degree of AD suggesting a gradual decline of immune responsiveness in AD.

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.

Action of prolactin, IFN-gamma, TNF-alpha 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.