Kaposi’s sarcoma-associated herpesvirus (KSHV) is believed to be the causative agent of Kaposi’s sarcoma (KS), a multicentric growth factor-dependent tumor common in AIDS patients characterized histopathologically by spindle cell proliferation, angiogenesis, and leukocyte infiltration. Recently, open reading frame 74 of KSHV has been implicated as a major viral determinant of KS. Open reading frame 74 encodes KSHV G protein-coupled receptor (GPCR), a constitutively active chemokine receptor that directly transforms NIH 3T3 cells in vitro and induces multifocal KS-like lesions in KSHV-GPCR-transgenic mice. Interestingly, receptor-positive cells are very rare in lesions from these mice, implicating an indirect mechanism of tumorigenesis. In this regard, here we report that expression of KSHV-GPCR in transfected epithelial, monocytic, and T cell lines induced constitutive activation of the immunoregulatory transcription factors AP-1 and NF-κB. This was associated with constitutive induction of the proinflammatory NF-κB-dependent cytokines IL-1β, IL-6, and TNF-α, and chemokines monocyte chemoattractant protein-1 and IL-8, as well as the AP-1-dependent basic fibroblast growth factor. In addition, IL-2 and IL-4 production was induced in transfected Jurkat T cells. Truncation of the final five amino acids in the cytoplasmic tail of KSHV-GPCR caused complete loss of its transforming and NF-κB-inducing activities, without affecting receptor expression or ligand binding. These data suggest that KS results in part from KSHV-GPCR induction of proinflammatory cytokine and growth factor gene expression, mediated by a signaling determinant within the last five amino acids of the C terminus, a domain that is also critical for direct cell transformation.

Chemokines are a family of small related proteins that play an important role in the selective recruitment of different leukocyte populations to the sites of inflammation. Human glomerular mesangial cells are potent producers of a variety of chemokines. Here we examined the kinetics of mesangial cell chemokine expression with focus on the C-C or beta chemokines monocyte chemoattractant protein-1 (MCP-1), regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-1 alpha (MIP-1 alpha), and the C-X-C or alpha chemokine interleukin-8 (IL-8) in response to lymphocyte- or monocyte-derived cytokines and mesangial cell growth factors. It was found that interferon-gamma (IFN-gamma), a cytokine produced by TH1 lymphocytes, synergized with tumor necrosis factor-alpha (TNF-alpha) in RANTES expression and with IL-1 beta in MCP-1 synthesis. Time course studies revealed an early peak of mRNA expression of monocyte-specific MCP-1 upon activation with TNF-alpha in contrast to T cell-specific RANTES, which reached the highest mRNA level after 18 hours. This sequence of TNF-alpha-induced MCP-1 and RANTES expression was confirmed on the protein level. As another T-lymphocyte specific chemokine, MIP-1 alpha mRNA and protein was expressed only in response to TNF-alpha plus IFN-gamma with kinetics similar to those of RANTES expression. Finally, unlike other mesangial growth factors basic fibroblast growth factor (bFGF) induced MCP-1, RANTES, and IL-8 mRNA expression, suggesting an involvement of autocrine regulation mechanisms in mesangial chemokine expression.

The deposition of immune complexes, followed by activation of complement and/or Fc receptors and generation of chemoattractants, is the most common feature of human glomerulonephritis. Recently we have shown that primary cultured human glomerular mesangial cells (HMC), which are normally negative for IgG Fc receptors, can be stimulated to express the low-affinity FcgammaRIII-A receptor isoform. In this study we further demonstrate that activation of HMC through IFN-gamma resulted in the functional expression of the high-affinity Fc receptor for IgG (FcgammaRI, CD64). IFN-gamma-dependent induction of classical FcgammaRIa1 mRNA as well as a2, b2 splice variants were evident after 24 h in proliferating HMC and after 48 h in resting HMC. Transcription of FcgammaRI mRNA was also induced by IL-10 in proliferating HMC, whereas other cytokines such as IL-3, transforming growth factor-beta1 and granulocyte-macrophage colony-stimulating factor were not effective. Cell surface expression of FcgammaRI could be detected by flow cytometric analysis after IFN-gamma stimulation and was accompanied by the augmentation of MHC class II and the up-regulation of intercellular adhesion molecule-1 expression. Triggering of HMC by cross-linking FcgammaRI with F(ab')2 fragments of the anti-CD64 monoclonal antibody 22 led to enhanced synthesis of mRNA for the chemokines IL-8 and monocyte chemoattractant protein-1, indicating that the FcgammaRI of HMC is functionally active. These in vitro data suggest that engagement of both FcgammaRI and FcgammaRIII-A on activated HMC through IgG immune complexes may result in an increased chemoattraction of leukocytes into the glomerulus, contributing to the development of glomerulonephritis.

Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report on the use of solvent-preserved, gamma-sterilized Tutoplast bovine pericardium for dural grafts in 32 patients undergoing cranial and spinal operations with the objective of clinically assessing this material and technique by a retrospective analysis. All available records were reviewed and information regarding the indication for grafting, complications, and outcome were collected and analyzed for all patients. Indications for grafting included tethered cord myelolysis, closure of lumbosacral myeloceles, Chiari decompression, posterior fossa craniotomy, supratentorial craniotomy, and trauma. Outcomes were excellent in 31 patients; the one poor outcome was unrelated to surgical closure. The dural graft was not intended for outcome in any patient. Bovine pericardium was found to be a flexible and easily suturable, safe and cost-effective material for duraplasty. These results confirm the excellent suitability of Tutoplast bovine pericardium for dural substitution.