We have studied cell death and its mechanisms in herpes simplex virus type 1 (HSV-1)-infected monocytic cells. The HSV-1 ICP4 and Us3 deletion mutant, d120 caused both apoptosis and necroptosis in d120-infected monocytic cells. At a late time point of infection the number of apoptotic cells was increased significantly in d120-infected cells when compared with uninfected or parental HSV-1 (KOS)-infected cells. Necroptosis inhibitor treatment increased the number of viable cells among the d120-infected cells, indicating that cell death in d120-infected cells was, in part, because of necroptosis. Moreover, lysosomal membrane permeabilization and cathepsin B and H activities were increased significantly in d120-infected cells. Inhibition of cathepsin B and S activities with specific cathepsin inhibitors led to increased cell viability, and inhibition of cathepsin L activity resulted in a decreased number of apoptotic cells. This indicates that cathepsins B, L and S may act as cell-death mediators in d120-infected monocytic cells. In addition, caspase 3 activity was increased significantly in d120-infected cells. However, the caspase 3 inhibitor treatment did not decrease the number of apoptotic cells. In contrast, inhibition of cathepsin L activity by cathepsin L-specific inhibitor clearly decreased caspase 3 activity and the number of apoptotic cells in d120-infected cells. This might suggest that, in d120-infected monocytic cells, cathepsin L activates caspase 3 and thus mediates d120-induced apoptosis. Taken together, these findings suggest that d120-induced cell death is both apoptotic and necroptotic. INTRODUCTIONHerpes simplex virus type 1 (HSV-1) is a common pathogen that replicates in a variety of cell types during acute infection . After lytic infection HSV-1 remains latent in the neurons of its host for life and can reactivate to cause lesions at or near the initial site of infection. Like other herpesviruses, HSV-1 expresses a large number of enzymes involved in nucleic acid metabolism, DNA synthesis and the processing of proteins. Productive viral infection is accompanied by inevitable cell destruction. HSV-1 has several strategies to combat the responses of the infected host, among them the prevention of the blocking protein kinase R-mediated shut-off of host protein synthesis (He et al., 1997), having a latent form of infection with no protein expression , blocking presentation of antigenic peptides on the cell surface (Fruh et al., 1995;Hill et al., 1995) and blocking apoptosis (Galvan & Roizman, 1998;Leopardi & Roizman, 1996;Leopardi et al., 1997).HSV-1 entry triggers the induction of apoptosis during the early stage of infection (Aubert & Blaho, 1999;Koyama & Adachi, 1997). However, HSV-1 is able to block apoptosis at multiple stages of infection to prevent the host cell from dying prematurely (Aubert & Blaho, 1999;Galvan & Roizman, 1998;Koyama & Miwa, 1997). For example, the late protein kinase Us3 contributes to blocking HSV-1-induced apoptosis (Leopardi et al., 1997;Munger & Roizman, 2001). Other...

The role of cystatins in herpes simplex virus (HSV)-induced apoptosis and viral replication has been studied. Human epithelial (HEp-2) cells infected with wild-type HSV-1 (F), with a deletion virus lacking the anti-apoptotic gene Us3 (R7041) or with a deletion virus lacking the anti-apoptotic genes Us3 and ICP4 (d120) were treated with cystatin A, C or D. Cells and culture media were studied at different time points for replicating HSV-1 and for apoptosis. Cystatins C and D inhibited the yield of replicative HSV-1 significantly in HEp-2 cells. In addition, cystatin D inhibited R7041 and d120 virus-induced apoptosis. Moreover, cystatin A inhibited R7041-induced apoptosis. These inhibitory effects of cystatins on virus replication and apoptosis are likely to be separate functions. Cystatin D treatment decreased cellular cathepsin B activity in HSV-1 infection, suggesting that cathepsin B is involved in virus-induced apoptosis.

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Background. We studied the effect of fast induction of cardiac arrest with denosine on myocardial bax and bcl-2 expression. Methods and Results. 40 elective CABG patients were allocated into two groups. The adenosine group (n = 20) received 250 μg/kg adenosine into the aortic root followed by blood potassium cardioplegia. The control group received potassium cardioplegia in blood. Bcl-2 and bax were measured. Bax was reduced in the postoperative biopsies (1.38 versus 0.47, P = .002) in the control group. Bcl-2 showed a reducing tendency (0.14 versus 0.085, P = .07). After the adenosine treatment, the expression of both bax (0.52 versus 0.59, P = .4) and bcl-2 (0.104 versus 0.107, P = .4) remained unaltered after the operation. Conclusion. Open heart surgery is associated with rapid reduction in the expression of apoptosis regulating genes bax and bcl-2. Fast Adenosine induction abolished changes in their expression.