Ilaria Volpi

Localized delivery of fibroblast growth factor–2 and brain-derived neurotrophic factor reduces spontaneous seizures in an epilepsy model

A loss of neurons is observed in the hippocampus of many patients with epilepsies of temporal lobe origin. It has been hypothesized that damage limitation or repair, for example using neurotrophic factors (NTFs), may prevent the transformation of a normal tissue into epileptic (epileptogenesis). Here, we used viral vectors to locally supplement two NTFs, fibroblast growth factor–2 (FGF-2) and brain-derived neurotrophic factor (BDNF), when epileptogenic damage was already in place. These vectors were first characterized in vitro, where they increased proliferation of neural progenitors and favored their differentiation into neurons, and they were then tested in a model of status epilepticus-induced neurodegeneration and epileptogenesis. When injected in a lesioned hippocampus, FGF-2/BDNF expressing vectors increased neuronogenesis, embanked neuronal damage, and reduced epileptogenesis. It is concluded that reduction of damage reduces epileptogenesis and that supplementing specific NTFs in lesion areas represents a new approach to the therapy of neuronal damage and of its consequences.

C-Reactive protein downregulates TRAIL expression in human peripheral monocytes via an Egr-1-dependent pathway.

Purpose: To investigate the potential link between C-reactive protein (CRP), a known biomarker of acute and chronic inflammation, and TRAIL, a cytokine which plays a key role in the immune-surveillance against tumors. Experimental Design: Primary normal peripheral blood mononuclear cell (PBMC) and CD14+ monocytes were exposed to recombinant CRP (1–10 μmol/L). TRAIL expression was analyzed by ELISA and/or by quantitative real-time PCR (qRT-PCR). In parallel, the potential role of the transcription factor Egr-1 was investigated by analyzing its modulation in response to CRP and by transfection experiments. Results: In vitro CRP exposure induced downregulation of TRAIL expression, both at the mRNA and protein level, in unfractionated PBMC and in purified CD14+ monocytes. TRAIL downregulation was not due to a specific toxicity or to contaminating lipopolysaccharide (LPS), as shown by the lack of induction of monocyte apoptosis and by the inability of the inhibitor of LPS polymyxin B to interfere with CRP activity. Of note, CRP downregulated TRAIL expression/release in CD14+ monocytes also in response to IFN-α, the most potent inducer of TRAIL. At the molecular level, the downmodulation of TRAIL by CRP was accompanied by a significant increase of Egr-1. Consistently, Egr-1 overexpression reduced the baseline levels of TRAIL mRNA, whereas knocking down Egr-1 counteracted the ability of CRP to downregulate TRAIL. Conclusions: Our findings suggest that a chronic elevation of CRP, which occurs during systemic inflammation and often in patients with cancer, might contribute to promote cancer development and/or progression by downregulating TRAIL in immune cells. Clin Cancer Res; 19(8); 1949–59. ©2013 AACR.

Endothelial cells obtained from patients affected by chronic venous disease exhibit a pro-inflammatory phenotype.

Background The inflammatory properties of vein endothelium in relation to chronic venous disease (CVD) have been poorly investigated. Therefore, new insights on the characteristics of large vein endothelium would increase our knowledge of large vessel physiopathology. Methodology/Principal Findings Surgical specimens of veins were obtained from the tertiary venous network (R3) and/or saphenous vein (SF) of patients affected by CVD and from control individuals. Highly purified venous endothelial cell (VEC) cultures obtained from CVD patients were characterized for morphological, phenotypic and functional properties compared to control VEC. An increase of CD31/PECAM-1, CD146 and ICAM-1 surface levels was documented at flow cytometry in pathological VEC with respect to normal controls. Of note, the strongest expression of these pro-inflammatory markers was observed in VEC obtained from patients with more advanced disease. Similarly, spontaneous cell proliferation and resistance to starvation was higher in pathological than in normal VEC, while the migratory response of VEC showed an opposite trend, being significantly lower in VEC obtained from pathological specimens. In addition, in keeping with a higher baseline transcriptional activity of NF-kB, the release of the pro-inflammatory cytokines osteoprotegerin (OPG) and vascular endothelial growth factor (VEGF) was higher in pathological VEC cultures with respect to control VEC. Interestingly, there was a systemic correlation to these in vitro data, as demonstrated by higher serum OPG and VEGF levels in CVD patients with respect to normal healthy controls. Conclusion/Significance Taken together, these data indicate that large vein endothelial cells obtained from CVD patients exhibit a pro-inflammatory phenotype, which might significantly contribute to systemic inflammation in CVD patients.

Endothelial PDGF-BB produced ex vivo correlates with relevant hemodynamic parameters in patients affected by chronic venous disease

Surgical specimens of vein were obtained from the tertiary venous network and/or saphenous vein from patients (n=20) affected by chronic venous disease (CVD). Into the venous segments, which subsequently were surgically ablated, the following hemodynamic parameters were assessed by echo-color-doppler (ECD): peak systolic velocity, end diastolic velocity, whose combination allowed the calculation of the resistance index (RI) and the reflux time (RT). Highly purified venous endothelial cell (VEC) cultures derived from venous segments of these CVD patients were then characterized for the profile of cytokines and chemokines released in the culture supernatants. Among the 27 cytokines and chemokines examined, we found a positive and significant correlation (R=0.5; p=0.03) only between the spontaneous release of PDGF-BB by VEC cultures and the RT values of the patients from which the VEC were isolates. In addition, the release of PDGF-BB in the VEC culture supernatants was significantly (p<0.01) increased upon in vitro treatment with recombinant TNF-α. By using pharmacological inhibitors, specific for the main pathways, NF-kB, ERK1/2 and p38 MAPK, activated by exposure of endothelial cells to TNF-α, we found that only NF-kB appeared to be significantly involved in mediating the PDGF-BB induction by TNF-α. Of interest, the release of PDGF-BB in response to the in vitro inflammatory stimulation, maintained a positive and significant correlation with RT (R=0.6; p=0.01), while showing a negative correlation with RI (R=-0.5; p=0.03). The potential implications of our findings for the pathophysiology of CVD are discussed.

Effects of defective herpes simplex vectors expressing neurotrophic factors on the proliferation and differentiation of nervous cells in vivo

Neurotrophic factors (NTFs) are known to govern the processes involved in central nervous system cell proliferation and differentiation. Thus, they represent very attractive candidates for use in the study and therapy of neurological disorders. We constructed recombinant herpesvirus-based-vectors capable of expressing fibroblast growth factor-2 (FGF-2) and ciliary neurotrophic factor (CNTF) alone or in combinations. In vitro, vectors expressing FGF-2 and CNTF together, but not those expressing either NTF alone, caused proliferation of O-2A progenitors. Furthermore, based on double-labeling experiments performed using markers for neurons (MAP-2), oligodendrocytes (CNPase) and astrocytes (GFAP), most of the new cells were identified as astrocytes, but many expressed neuronal or oligodendrocytic markers. In vivo, vectors have been injected in the rat hippocampus. At 1 month after inoculation, a highly significant increase in BrdU-positive cells was observed in the dentate gyrus of animals injected with the vector expressing FGF-2 and CNTF together, but not in those injected with vectors expressing the single NTFs. Furthermore, double-labeling experiments confirmed in vitro data, that is, most of the new cells identified as astrocytes, some as neurons or oligodendrocytes. These data show the feasibility of the vector approach to induce proliferation and differentiation of neurons and/or oligodendrocytes in vivo.

Characterization of herpes simplex virus 1 strains as platforms for the development of oncolytic viruses against liver cancer.

Diverse oncolytic viruses (OV) are being designed for the treatment of cancer. The characteristics of the parental virus strains may influence the properties of these agents.

Release of a specific set of proinflammatory adipokines by differentiating 3T3-L1 cells

OBJECTIVE Although there is a large amount of data on the role of preadipocytes in promoting the release of proinflammatory cytokines and chemokines in response to macrophage-derived cytokines, the direct role of insulin and saturated fatty acids in modulating the release of inflammatory cytokines by cells differentiating along the adipocytic lineage is less understood. METHODS 3T3-L1 murine preadipocyte cells were cultured for 3 d in a proliferating medium in the presence or absence of insulin 0.2 nmol/L plus palmitic acid 1 μmol/L. In parallel, 3T3-L1 cells were cultured in a differentiation medium containing dexamethasone, insulin, and isobutyl methyl xanthine in the absence or presence of palmitic acid for 3 d. The levels of several cytokines were evaluated in the culture supernatants by a bead-based multiplex immunoassay. RESULTS Under the proliferation conditions, insulin plus palmitic acid promoted a significant increase in the release of interleukin-6, keratinocyte-derived chemokine (KC)/chemokine ligand-1 (CXCL-1), monocyte chemotactic protein-1 (MCP-1), and regulated and normal T cells expressed and presumably secreted (RANTES) by 3T3-L1 preadipocytes. Of note, the release of KC/CXCL-1, MCP-1, and RANTES increased significantly with adipocytic differentiation, and the addition of palmitic acid to differentiating 3T3-L1 cells resulted in a further significant promotion of KC/CXCL1, MCP-1, and RANTES, coupled to the increase of additional cytokines. CONCLUSIONS Taken together, these data show that a restricted common group of cytokines/chemokines (KC/CXCL1, MCP-1, and RANTES) is upregulated in proliferating and differentiating 3T3-L1 adipocytes in response to insulin and palmitic acid and that differentiating adipocytes respond with an increased range of cytokines with respect to proliferating 3T3-L1 preadipocytes.

An Attenuated Herpes Simplex Virus Type 1 (HSV1) Encoding the HIV-1 Tat Protein Protects Mice from a Deadly Mucosal HSV1 Challenge

Herpes simplex virus types 1 and 2 (HSV1 and HSV2) are common infectious agents in both industrialized and developing countries. They cause recurrent asymptomatic and/or symptomatic infections, and life-threatening diseases and death in newborns and immunocompromised patients. Current treatment for HSV relies on antiviral medications, which can halt the symptomatic diseases but cannot prevent the shedding that occurs in asymptomatic patients or, consequently, the spread of the viruses. Therefore, prevention rather than treatment of HSV infections has long been an area of intense research, but thus far effective anti-HSV vaccines still remain elusive. One of the key hurdles to overcome in anti-HSV vaccine development is the identification and effective use of strategies that promote the emergence of Th1-type immune responses against a wide range of epitopes involved in the control of viral replication. Since the HIV1 Tat protein has several immunomodulatory activities and increases CTL recognition of dominant and subdominant epitopes of heterologous antigens, we generated and assayed a recombinant attenuated replication-competent HSV1 vector containing the tat gene (HSV1-Tat). In this proof-of-concept study we show that immunization with this vector conferred protection in 100% of mice challenged intravaginally with a lethal dose of wild-type HSV1. We demonstrate that the presence of Tat within the recombinant virus increased and broadened Th1-like and CTL responses against HSV-derived T-cell epitopes and elicited in most immunized mice detectable IgG responses. In sharp contrast, a similarly attenuated HSV1 recombinant vector without Tat (HSV1-LacZ), induced low and different T cell responses, no measurable antibody responses and did not protect mice against the wild-type HSV1 challenge. These findings strongly suggest that recombinant HSV1 vectors expressing Tat merit further investigation for their potential to prevent and/or contain HSV1 infection and dissemination.

Antitumor effects of non-replicative herpes simplex vectors expressing antiangiogenic proteins and thymidine kinase on Lewis lung carcinoma establishment and growth.

There is growing evidence that combinations of antiangiogenic proteins with other antineoplastic treatments such as chemo- or radiotherapy and suicide genes-mediated tumor cytotoxicity lead to synergistic effects. In the present work, we tested the activity of two non-replicative herpes simplex virus (HSV)-1-based vectors, encoding human endostatin∷angiostatin or endostatin∷kringle5 fusion proteins in combination with HSV-1 thymidine kinase (TK) molecule, on endothelial cells (ECs) and Lewis lung carcinoma (LLC) cells. We observed a significant reduction of the in vitro growth, migration and tube formation by primary ECs upon direct infection with the two recombinant vectors or cultivation with conditioned media obtained from the vector-infected LLC cells. Moreover, direct cytotoxic effect of HSV-1 TK on both LLC and ECs was demonstrated. We then tested the vectors in vivo in two experimental settings, that is, LLC tumor growth or establishment, in C57BL/6 mice. The treatment of pre-established subcutaneous tumors with the recombinant vectors with ganciclovir (GCV) induced a significant reduction of tumor growth rate, while the in vitro infection of LLC cells with the antiangiogenic vectors before their implantation in mice flanks, either in presence or absence of GCV, completely abolished the tumor establishment.