Background Emerging evidence showed that resistin induces vascular smooth muscle cell (VSMC) migration, a critical step to initiating vascular restenosis. Mechanistically, adhesion molecule expression and cytoskeletal rearrangement have been observed in this progress. Given that matrix metalloproteinases (MMPs) also regulates cell migration, we hypothesized that MMPs may mediate resistin-induced VSMC migration. Materials and Methods Human VSMCs were treated with recombinant human resistin at physiological (10 ng/mL) and pathological (40 ng/mL) concentrations for 24 hours. Cell migration was determinate by Boyden chamber assay. MMP and TIMP mRNA and protein levels were measured with real-time PCR and ELISA. MMP enzymatic activity was measured by zymography on precast gels. In another experiment, neutralizing antibodies against MMP-2 and MMP-9 were co-incubated with resistin in cultured VSMCs. The regulation of MMP by protein kinase C (PKC) was determined by εV1–2, a selective PKCε inhibitor. Results Resistin-induced SMC migration was confirmed by Boyden chamber assay. 40ng/mL Resistin increased SMC migration by 3.7 fold. Molecularly, resistin stimulated MMP-2 and - MMP9 mRNA and protein expressions. In contrast, the TIMP-1 and TIMP-2 mRNA levels were inhibited by resistin. Neutralizing antibodies against MMP-2 and MMP-9 effectively reversed VSMC migration. Furthermore, resistin activated PKCε and selective PKCε inhibitor suppressed resistin-induced MMP expression, activity and cell migration. Conclusions Our study confirmed that resistin increases vascular smooth muscle cell migration in vitro. Mechanistically, resistin-stimulated cell migration was associated with increased MMP expression and activity, which was dependent on PKCε activation.

Vascular restenosis, an overreaction of biological response to injury, is initialized by thrombosis and inflammation. This response is characterized by increased smooth muscle cell migration and proliferation. Available pharmacological treatments include anticoagulants, antiplatelet agents, immunosuppressants and antiproliferation agents. Protein kinase C (PKC), a large family of serine/threonine kinases, has been shown to participate in various pathological stages of restenosis. Consequently, PKC inhibitors are expected to exert a wide range of pharmacological activities therapeutically beneficial for restenosis. In this review, the roles of PKC isozymes in platelets, leukocytes, endothelial cells and smooth muscle cells are discussed, with emphasis given to smooth muscle cells. We will describe cellular and animal studies assessing prevention of restenosis with PKC inhibitors, particularly targeting -alpha, -beta, -delta and -zeta isozymes. The delivery strategy, efficacy and safety of such PKC regulators will also be discussed.

The incubation of human peripheral blood monocytes with endotoxins activates the cells to lyse tumorigenic targets directly and also induces the production and release into the culture medium of factors that produce lysis of mouse-transformed fibroblasts L-929 (tumor necrosis factor (TNF)-sensitive) and human A-375 melanoma cells (interleukin-1 (IL-1)- and TNF-sensitive). Immunoblotting analysis revealed that the culture medium of endotoxin-activated but not of control monocytes contained both IL-1 and TNF with a molecular weight of 17,000 daltons each. TNF activity was determined by lysis of L-929 cells, and IL-1 activity was measured by the proliferation of D-10 cells. The production of IL-1 and TNF was concentration-dependent, and the amounts of these monokines were paralleled. The antitumor activity of the culture supernates from endotoxin-treated monocytes was significantly decreased by incubation with heterologous antisera to IL-1, TNF, or both. Recombinant human IL-1 and TNF were used in parallel experiments and as positive controls. Each monokine used produced cytotoxic effects in susceptible targets. The combination of IL-1 and TNF, which more likely resembles culture supernates of activated macrophages, produced an additive antitumor cytotoxicity effect.

The cellular immune defect in untreated Hodgkin's disease (HD) has long been recognized. This defect appears to be responsible for at least some of the morbidity and ultimately the mortality associated with the disease. In recent years, many studies have shown that the T cell component of the immune response is the apparent site where the defect in HD exists and where the immunoregulatory abnormalities that may account for the deficit are observed. The discovery of the lymphokines and monokines, comprising the human interleukin system, has elucidated some aspects of the regulatory control of the functional pathways involved in T lymphocyte activation and proliferation. The interleukin system can therefore provide the framework to dissect immunodeficiency states, such as that seen in HD. The present study indicates that HD patients' interleukin 1 (IL1) response appears to be normal, as is their T cell proliferative response to exogenous IL2. Interleukin 2 production by HD patients' peripheral blood mononuclear cells, however, is decreased when compared with age/sex-matched controls. The inability to generate IL2 after appropriate stimulation may reflect either a primary cellular defect or a regulatory defect, such as excessive immunosuppression, giving rise to the characteristic T cell hyporesponsiveness seen in HD.

No abstract