Apoptosis: definition, mechanisms, and relevance to disease

Survivin enhances Fas ligand expression via up-regulation of specificity protein 1-mediated gene transcription in colon cancer cells

Cancer cells are thought to possess mechanisms for evading the host's immune surveillance system. Survivin, a member of the inhibitor-of-apoptosis family overexpressed by cancer cells, inhibits Fas-mediated apoptosis induced by immune cells. In addition, cancer cells express Fas ligand (FasL) on their surfaces as a counterattack against immune cells. Mechanisms by which cancer cells express FasL, including involvement of survivin, are unclear. In the present study, we demonstrated that survivin up-regulated FasL expression and investigated how this might occur. Quantitative immunostaining showed correlation between survivin and FasL protein expression in colon cancer tissues (r=0.79). FasL expression was up-regulated in LS180 colon cancer cells transfected with the survivin gene. Transfectants showed increased cytotoxicity against a Fas-sensitive human T leukemia cell line, Jurkat. In contrast, FasL expression was down-regulated in SW480 cells transfected with a small inhibitory RNA to prevent survivin expression. Survivin gene transfectants showed increased DNA binding of transcription factor specificity protein 1 (Sp1) to the FasL promoter, and up-regulation of Sp1 phosphorylation at serine and threonine residues; the total amount of Sp1 was unchanged. Thus, survivin enables cancer cells not only to suppress immune cell attack by inhibiting Fas-mediated apoptotic signaling, but to attack immune cells by induction of FasL.

Cultured Primary Osteoblast Viability and Apoptosis in the Presence of Root Canal Sealers

This study was designed to test the hypothesis that Roekoseal is less cytotoxic than eugenol-based Sealapex or calcium hydroxide-based Kerr's Pulp Canal Sealer. Embryonic, day-19, rat calvarial osteoblasts were cultured at 4 x 10(5) cells/well. The concentration of conditioned medium from each sealer producing 50% surviving cells (ED50) was determined and long-term viability and apoptosis of cells assessed after exposure to the ED50 of each sealer. Low concentrations of Kerr's Pulp Canal Sealer (190 mm(2)/1 ml) and high concentrations of Sealapex and Roekoseal (190 mm(2)/300 microl) produced the ED50. ED50 challenged osteoblasts had fewer viable cells at 72 h than at 24 h, with significantly more viable cells in the Roekoseal group. There was significantly less apoptotic activity in cells exposed to Roekoseal ED50 than in cells exposed to Kerr's Pulp Canal Sealer (p < 0.05) ED50. Roekoseal may be less cytotoxic than Kerr's Pulp Canal Sealer, but further studies of this new sealer are required.

Role of Toll-like receptor 4 in endotoxin-induced acute renal failure

Toll-like receptor 4 (TLR4) is present on monocytes and other cell types, and mediates inflammatory events such as the release of TNF after exposure to LPS. C3H/HeJ mice are resistant to LPS-induced mortality, due to a naturally occurring mutation in TLR4. We therefore hypothesized that LPS-induced acute renal failure (ARF) requires systemic TNF release triggered by LPS acting on extrarenal TLR4. We injected C3H/HeJ mice and C3H/HeOuJ controls with 0.25 mg of LPS, and sacrificed them 6 h later for analysis of blood urea nitrogen (BUN) and kidney tissue (n = 8 per group). In contrast to C3H/HeOuJ controls, C3H/HeJ mice were completely resistant to LPS-induced ARF (6-h BUN of 32.3 +/- 1.1 vs 61.7 +/- 5.6 mg/dl). C3H/HeJ mice released no TNF into the circulation at 2 h (0.00 vs 1.24 +/- 0.16 ng/ml), had less renal neutrophil infiltration (6.4 +/- 1.0 vs 11.4 +/- 1.3 neutrophils per high power field), and less renal apoptosis, as assessed by DNA laddering. Transplant studies showed that C3H/HeJ recipients of wild-type kidneys (n = 9) were protected from LPS-induced ARF, while wild-type recipients of C3H/HeJ kidneys (n = 11) developed severe LPS-induced ARF (24-h BUN 44.0 +/- 4.1 vs 112.1 +/- 20.0 mg/dl). These experiments support our hypothesis that LPS acts on extrarenal TLR4, thereby leading to systemic TNF release and subsequent ARF. Renal neutrophil infiltration and renal cell apoptosis are potential mechanisms by which endotoxemia leads to functional ARF.

Oral graft-versus-host disease and programmed cell death: pathogenetic and clinical correlates

Graft-versus-host disease (GVHD) is an untoward complication of bone marrow transplantation. It is characterized by an immune-mediated attack by donor immune cells against various host cells and tissues, a process which may be associated with significant morbidity in affected patients. Oral lesions are a common sequelae and can serve as a highly predictive index to the presence of systemic GVHD. The oral lesions of GVHD are clinically and histologically lichenoid in nature and can be a challenge in terms of management. Ulcerated and painful mucosal lesions may represent a significant impediment to normal eating habits and nutritional intake, necessitating appropriate diagnosis and treatment. Importantly, recent evidence has indicated that programmed cell death, or apoptosis, is the major constituent in the pathogenesis of GVHD. Apoptosis not only plays a major role in normal growth and ontogeny, but has been shown to contribute to a wide spectrum of both inflammatory and neoplastic disorders. Since knowledge of apoptotic molecular pathways is requisite for understanding GVHD, the purpose of this paper is to provide a fundamental overview of the predominant apoptotic mechanisms implicated in the pathogenesis of GVHD and to relate these findings to the oral complications of the disease. Finally, we will discuss management strategies for diagnosing and treating the oral lesions of GVHD. By explicating the molecular events in the apoptotic pathway, unique therapeutic and pharmacologic strategies for regulating apoptosis may be developed in the future, reducing the morbidity associated with conditions like GVHD.

Apoptosis-detecting radioligands: current state of the art and future perspectives

This review provides a critical and thorough overview of the radiopharmaceutical development and in vivo evaluation of all apoptosis-detecting radioligands that have emerged so far, along with their possible applications in nuclear medicine. The following SPECT and PET radioligands are discussed: all forms of halogenated Annexin V (i.e. (123)I-labelled, (124)I-labelled, (125)I-labelled, (18)F-labelled), (99m)Tc/(94m)Tc-labelled Annexin V derivatives using different chelators and co-ligands (i.e. BTAP, Hynic, iminothiolane, MAG(3), EDDA, EC, tricarbonyl, SDH) or direct (99m)Tc-labelling, (99m)Tc-labelled Annexin V mutants and (99m)Tc/(18)F-radiopeptide constructs (i.e. AFIM molecules), (111)In-DTPA-PEG-Annexin V, (11)C-Annexin V and (64)Cu-, (67)Ga- and (68)Ga-DOTA-Annexin V. In addition, the potential role and clinical relevance of anti-PS monoclonal antibodies and other alternative apoptosis markers are reviewed, including: anti-Annexin V monoclonal antibodies, radiolabelled caspase inhibitors and substrates and mitochondrial membrane permeability targeting radioligands. Nevertheless, major emphasis is placed on the group of Annexin V-based radioligands, in particular (99m)Tc-Hynic-Annexin V, since this molecule is by far the most extensively investigated and best-characterised apoptosis marker at present. Furthermore, the newly emerging imaging modalities for in vivo detection of programmed cell death, such as MRI, MRS, optical, bioluminescent and ultrasound imaging, are briefly described. Finally, some future perspectives are presented with the aim of promoting the development of potential new strategies in pursuit of the ideal cell death-detecting radioligand.

Tumour necrosis factor-alpha and apoptosis in the rat temporomandibular joint

The purpose of this investigation was to investigate the roles that tumour necrosis factor-alpha (TNF-alpha) and apoptosis play during acute inflammation of the temporomandibular joint (TMJ). Adult male Sprague-Dawley rats were injected with complete Freund's adjuvant (CFA) into the TMJ or kept as uninjected controls. The TMJ tissues were removed 2 days post-injection to mimic conditions of acute inflammation and analysed for changes in expression of TNF-alpha, the receptor TNF-R1, caspase-3 and -8, and apoptosis. Concentrations of TNF-alpha, TNF-R1, caspase-3 and -8, and apoptosis were significantly elevated in CFA-injected animals compared to uninjected controls. Tissue incubation with TNF-alpha caused a significant increase in caspase-3 and -8. Also, levels of apoptosis were significantly increased during inflammation, which could be inhibited by the addition of either anti-TNF-alpha neutralising antibody or caspase inhibitors. TNF-alpha may play a significant role in the onset of acute CFA-induced TMJ inflammation, and activation of apoptosis signalling pathways may be involved.

Redox and oxidant-mediated regulation of apoptosis signaling pathways: immuno-pharmaco-redox conception of oxidative siege versus cell death commitment

The mechanisms controlling apoptosis remain largely obscure. Because apoptosis is an integral part of the developmental program and is frequently the end-result of a temporal course of cellular events, it is referred to as programmed cell death. While there is considerable variation in the signals and requisite cellular metabolic events necessary to induce apoptosis in diverse cell types, the morphological features associated with apoptosis are highly conserved. Free radicals, particularly reactive oxygen species (ROS), have been proposed as common mediators for apoptosis. Many agents that induce apoptosis are either oxidants or stimulators of cellular oxidative metabolism. Conversely, many inhibitors of apoptosis have antioxidant activities or enhance cellular antioxidant defenses. Mammalian cells, therefore, exist in a state of oxidative siege in which survival requires an optimum balance of oxidants and antioxidants. The respiratory tract is subjected to a variety of environmental stresses, including oxidizing agents, particulates and airborne microorganisms that, together, may injure structural and functional lung components and thereby jeopardize the primary lung function of gas exchange. To cope with this challenge, the lung has developed elaborate defense mechanisms that include inflammatory-immune pathways as well as efficient antioxidant defense systems. In the absence of adequate antioxidant defenses, the damage produced is detected by the cell leading to the activation of genes responsible for the regulation of apoptosis, conceivably through stress-responsive transcription factors. Oxidative stress, in addition, may cause a shift in cellular redox state, which thereby modifies the nature of the stimulatory signal and which results in cell death as opposed to proliferation. ROS/redox modifications, therefore, may disrupt signal transduction pathways, can be perceived as abnormal and, under some conditions, may trigger apoptosis.

Pdcd4 inhibits growth of tumor cells by suppression of carbonic anhydrase type II

To identify new genes that are upregulated during apoptosis we previously cloned rat pdcd4. While the role of pdcd4 is still unclear it seems to possess a tumor suppressor activity. Pdcd4 directly interacts with the RNA helicase eIF4A and inhibits protein synthesis by interfering with the assembly of the cap-dependent translation initiation complex. In the present study, we show that pdcd4 suppresses carbonic anhydrase type II protein expression in HEK293 and Bon-1 carcinoid cells. Since tumor cells require a high bicarbonate flux for their growth, carbonic anhydrase suppression results in growth inhibition. Similar to pdcd4, carbonic anhydrase inhibitor ethoxyzolamide reduces growth of several endocrine tumor cell lines. Thus, the translation inhibitor pdcd4 represses endocrine tumor cell growth by suppression of carbonic anhydase II. Furthermore, carbonic anhydrase inhibitors might represent promising tools for anti-endocrine tumor treatment.

Is innervation an early target in autoimmune diabetes?

In the non-obese diabetic (NOD) mouse, a spontaneous model of type 1 diabetes (T1D), recent evidence suggests that Schwann cells (Scs) and neurons surrounding insulin-producing beta cells of the islets of Langerhans are destroyed before beta cells. During normal perinatal development, macrophages (MPhi) are involved in phagocytosis of apoptotic neurons. Pertinently, MPhi are already present at birth in NOD pancreata. Their possible abnormal control of nerve phagocytosis, together with transient beta-cell hyperactivity and lymphocyte anomalies, might conjointly participate in T1D pathogenesis.

Mediating of caspase-independent apoptosis by cadmium through the mitochondria-ROS pathway in MRC-5 fibroblasts

Cadmium (Cd) is an environmental pollutant of global concern with a 10-30-year biological half-life in humans. Accumulating evidence suggests that the lung is one of the major target organs of inhaled Cd compounds. Our previous report demonstrated that 100 microM Cd induces MRC-5 cells, normal human lung fibroblasts, to undergo caspase-independent apoptosis mediated by mitochondrial membrane depolarization and translocation of apoptosis-inducing factor (AIF) from mitochondria into the nucleus. Here, using benzyloxycarbonyl-Val-Ala-Asp-(ome) fluoromethyl ketone (Z-VAD.fmk) as a tool, we further demonstrated that Cd could induce caspase-independent apoptosis at concentrations varied from 25 to 150 microM, which was modulated by reactive oxygen species (ROS) scavengers, such as N-acetylcysteine (NAC), mannitol, and tiron, indicating that ROS play a crucial role in the apoptogenic activity of Cd. Consistent with this notion, the intracellular hydrogen peroxide (H2O2) was 2.9-fold elevated after 3 h of Cd treatment and diminished rapidly within 1 h as detected by flow cytometry with 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Using inhibitors of the mitochondrial electron transport chain (ETC) (oligomycin A and rotenone for complex I and V, respectively) and mitochondrial permeability transition pore (MPTP) (cyclosporin A and aristolochic acid), we coincidently found the ROS production, mitochondrial membrane depolarization, and apoptotic content were almost completely or partially abolished. As revealed by confocal microscopy staining with chloromethyl-X-rosamine (CMXRos) and an anti-AIF antibody, the collapse of mitochondrial membrane potential induced by Cd (3 h-treatment) was a prelude to the translocation of caspase-independent pro-apoptotic factor, AIF, into the nucleus (after 4 h of Cd treatment). In summary, this study demonstrated that, in MRC-5 fibroblasts, Cd induced caspase-independent apoptosis through a mitochondria-ROS pathway. More importantly, we provide several lines of evidence supporting a role of mitochondrial ETC and MPTP in the regulation of caspase-independent cell death triggered by Cd.

Neuroendocrine Immuno-ontogeny of the Pathogenesis of Autoimmune Diabetes in the Nonobese Diabetic (NOD) Mouse

Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease in which insulin-producing beta cells of the pancreatic islets of Langerhans are destroyed. The nonobese diabetic (NOD) mouse is one of the rare spontaneous models that enable the study of prediabetic pancreatic events. The etiology of the autoimmune attack in human and animal T1D is still unknown, but genetic and environmental factors are involved in both cases. Although several autoantigens have been identified and defective immune-system regulation is implicated, this information does not satisfactorily explain the generally accepted beta-cell specificity of the disease or how so many and diverse environmental factors intervene in its pathogenesis. Based on data obtained from evaluating glucose homeostasis in a variety of situations, particularly stress and cytokine administration, in young prediabetic NOD mice, the author hypothesizes that the islet of Langerhans is a major actor, and its altered regulation through environmentally induced insulin resistance might reveal latent T1D. It is also postulated that T1D pathogenesis might be linked to abnormal pancreas development, probably due to disturbances of glutamic acid decarboxylase (GAD)+ innervation phagocytosis by defective macrophages during the early postnatal period. Also discussed is the role of defective presentation of pancreatic hormones and GAD in the thymus, and its potential repercussion on T-cell tolerance. Observations have demonstrated that the diabetogenic process in the NOD mouse is extremely complex, involving neuroendocrine immune interaction from fetal life onward.

Survivin as a predictor of cis-diamminedichloroplatinum sensitivity in gastric cancer patients

Survivin, a member of the inhibitor-of-apoptosis family, inhibits apoptosis by blocking caspase-3 and -7 activation. Gastric cancer, which is among the most intractable of malignant tumors, is known for resistance to various drugs, including cis-diamminedichloroplatinum (CDDP). Since this agent induces apoptosis via caspase-3 activation, survivin may mediate the drug resistance. We investigated survivin messenger RNA (mRNA) expression in gastric cancers and the relationship between expression and sensitivity to CDDP. Expression of the survivin gene was significantly up-regulated in gastric cancers compared to the tissues of normal mucosa, atrophic gastritis, and intestinal metaplasia (P < 0.0001) as assessed by a quantitative reverse transcription-polymerase chain reaction (RT-PCR), and was negatively associated with overall survival of patients who received CDDP-based chemotherapy. To investigate whether survivin is a resistance factor against CDDP-induced apoptosis, we transfected wild-type and dominant-negative mutants of the survivin gene into gastric cancer cells using a lipofection method. Overexpression of survivin protected MKN45 cells from CDDP-induced apoptosis. Expression of the dominant-negative mutant of the survivin gene sensitized NUGC-3 cells to drug-induced apoptosis. These results indicate that survivin may be pivotal in the development of gastric cancer and resistance to CDDP, and therefore controlling expression of the survivin gene may be therapeutically useful.

Bid activation in kidney cells following ATP depletion in vitro and ischemia in vivo

Bid is a proapoptotic Bcl-2 family protein, which on activation translocates to mitochondria and induces damage to the organelles. Activation of Bid depends on its proteolytic processing into truncated forms of tBid. Bid is highly expressed in the kidneys; however, little is known about its role in renal pathophysiology. In this study, we initially examined Bid activation in cultured rat kidney proximal tubular cells following ATP depletion. The cells were depleted of ATP by azide incubation in the absence of metabolic substrates and then returned to normal culture medium for recovery. Typical apoptosis developed during recovery of ATP-depleted cells. This was accompanied by Bid cleavage, releasing tBid of 15 and 13 kDa. Bid cleavage was abolished in cells overexpressing Bcl-2, an antiapoptotic gene. It was also suppressed by caspase inhibitors. Peptide inhibitors of caspase-9 were more effective in blocking Bid cleavage compared with inhibitors of caspase-8 and caspase-3. Provision of glucose, a glycolytic substrate, during azide incubation inhibited Bid cleavage as well, indicating that Bid cleavage was initiated by ATP depletion. Consistently, Bid cleavage was also induced following ATP depletion by hypoxia or mitochondrial uncoupling. Of significance, cleaved Bid translocated to mitochondria, suggesting a role for Bid in the development of mitochondrial defects in ATP-depleted cells. Finally, Bid cleavage was induced during renal ischemia-reperfusion in the rat. Together, these results provide the first evidence for Bid activation in kidney cells following ATP depletion in vitro and renal ischemia in vivo.

Apoptosis in the canine endometrium during the estrous cycle

Apoptotic cell death in the endometria of 58 female dogs in different stages of the estrous cycle was assessed (in formalin-fixed, paraffin-embedded sections) with both the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay and immunohistochemical detection of caspase-3 activity. For both techniques, the apoptotic index was determined in the surface epithelium, stroma, crypts, and basal glands by counting the percentage of stained cells in a total of 500 cells in each category. In the surface epithelium and stroma, TUNEL- and caspase-3-positive cells were rare (apoptotic index<1) throughout the estrous cycle. However, caspase-3 detection showed a significant increase in the apoptotic index in the stroma during anestrus as well as an increase in the index in both the stroma and surface epithelium in late metestrus. The apoptotic index increased during late metestrus and anestrus in the crypts and basal glands; in the crypts, this increase was significant only when caspase-3 detection was used, whereas in basal glands, significant differences were found for both techniques. In conclusion, apoptosis was present in canine endometrial cells during the estrous cycle, but caspase-3 detection showed more significant differences than the TUNEL assay. Furthermore, a high apoptotic index (suggestive of endometrial desquamation) was not detected in the surface epithelium and there was no significant correlation between the apoptotic index in any cell group and serum progesterone concentrations.

Redox regulation of PI3K/Akt and p53 in bovine aortic endothelial cells exposed to hydrogen peroxide

To clarify the apoptotic and survival signal transduction pathways in activated vascular endothelial cells exposed to oxidative stress, the effects of inhibitors of signal transduction on hydrogen peroxide (H(2)O(2))-induced apoptosis in bovine aortic vascular endothelial cells (BAEC) were examined. Treatment of BAEC with 1 mM H(2)O(2) caused increases of DNA fragmentation, p53 expression, Bax/Bcl-2 ratio, and the activities of caspases 3 and 9. The increases of DNA fragmentation, Bax/Bcl-2 ratio, and caspase activities were abrogated by BAPTA-AM (an intracellular Ca(2+) chelator) and N-acetyl-L-cysteine (an antioxidant), and augmented by wortmannin [a phosphatidylinositol 3-kinase (PI3K) inhibitor]. The increase of the intracellular Ca(2+) concentration ([Ca(2+)](i)) observed in H(2)O(2)-stimulated cells was unaffected by wortmannin, suggesting that the potentiating effect of wortmannin on the apoptosis was not due to an alteration of [Ca(2+)](i). H(2)O(2) increased the levels of PI3K activity and Akt phosphorylation. Both were attenuated by wortmannin and, to a lesser extent, by genistein (a tyrosine kinase inhibitor) and suramin (a growth factor receptor inhibitor), but not affected by BAPTA-AM. These results suggest that H(2)O(2) induces Ca(2+)-dependent apoptosis and Ca(2+)-independent survival signals such as redox-regulated activation of PI3K/Akt, which is partly mediated by the activation of growth factor receptors in BAEC.

Pancuronium bromide, a non-depolarizing muscle relaxant which promotes apoptosis of blood lymphocytes in vitro

BACKGROUND

Several compounds used in anesthesia practice have demonstrated to impair immune function and to influence the process of apoptotic death in T cell population following surgical trauma. We designed this study to test in vitro the impact of neuromuscular blocker, such as pancuronium, at clinically relevant concentration on lymphocyte apoptosis, death factor expression and mitochondrial function.

METHODS

Following isolation, lymphocytes were incubated with pancuronium bromide at a clinically relevant concentration (0.136 micro mol l-1) for 3 h at 37 C in a 5% carbon-dioxide-humidified atmosphere and the frequency of apoptotic lymphocytes was then measured. We also investigated crucial steps in the apoptotic process, including Fas/Fas ligand (FasL) phenotype, intracellular expression of the interleukin-1beta-converting enzyme (ICE) p20, mitochondrial membrane potential (DeltaPsim), generation of mitochondrial reactive oxygen species, and glutathione (GSH) levels. Control experiments were performed incubating cells in the complete culture medium added with the dilution medium of the drug without addition of the drug.

RESULTS

Expression of Fas, FasL and ICEp20 was six-fold, four-fold, and five-fold increased, respectively, among pancuronium-treated lymphocytes with respect to control cultures (P = 0.0001). The percentage of cells exhibiting either dissipation of mitochondrial membrane potential or increased production of reactive oxygen species was seven-fold increased following exposure to pancuronium compared with untreated lymphocytes (P = 0.0001). These findings were associated with a decrease in GSH level. In addition, the frequency of apoptotic cells was 10-fold greater among lymphocytes cultured in the presence of the drug with respect to control cultures. (P = 0.0001).

CONCLUSION

Our data suggest an apoptogenic effect of pancuronium in vitro at clinically relevant concentration on peripheral blood lymphocytes. This could be implicated in the transient immune suppression following a surgical operation.

Chemical discovery and global gene expression analysis in zebrafish

The zebrafish (Danio rerio) provides an excellent model for studying vertebrate development and human disease because of its ex utero, optically transparent embryogenesis and amenability to in vivo manipulation. The rapid embryonic developmental cycle, large clutch sizes and ease of maintenance at large numbers also add to the appeal of this species. Considerable genomic data has recently become publicly available that is aiding the construction of zebrafish microarrays, thus permitting global gene expression analysis. The zebrafish is also suitable for chemical genomics, in part as a result of the permeability of its embryos to small molecules and consequent avoidance of external confounding maternal effects. Finally, there is increasing characterization and analysis of zebrafish models of human disease. Thus, the zebrafish offers a high-quality, high-throughput bioassay tool for determining the biological effect of small molecules as well as for dissecting biological pathways.

Induction of apoptosis in macrophage cell line, J774, by the cell-free supernatant from Pseudomonas aeruginosa

Pseudomonas aeruginosa is able to secrete many virulence factors that are cytotoxic towards eukaryotic cells. To investigate the effect of the bacterium on macrophages, we obtained cell-free supernatants from P. aeruginosa (Pa) IID1117 (elastase-positive and protease-positive) and Pa IID1130 (elastase-positive and protease-negative). After 6 hr of incubation with the cell-free supernatant from the Pa IID1117 strain, the viability of J774 macrophages was shown to be significantly reduced (47.5+/-11%), but not Pa IID1130 (96.4+/-1.6%) at a concentration of 10% (v/v) compared to control J774 macrophages without any supernatant (97.2+/-1.7%) by the detection of trypan blue dye exclusion. The death of cells was further demonstrated to be due to apoptosis characterized by chromatin condensation and apoptotic bodies by Hoechst 33258 staining, DNA fragmentation by agarose gel electrophoresis and terminal deoxynucleotidyl transferase-mediated d-UTP nick end labeling (TUNEL). An activated subunit was found to be released from procaspase-3 in cell lysate. But in the presence of protease inhibitor, the apoptosis was completely blocked. The findings indicate that the Pa IID1117 strain is capable of inducing apoptosis in J774 macrophages. The apoptosis induced by the cell-free supernatant from Pa IID1117 strain is suggested to be dependent on protease, but not elastase.

Release of cytochrome c and activation of caspases related to myocyte apoptosis in obstructed ureters in a rat model of obstructive uropathy

OBJECTIVE

To investigate the roles of cytochrome c and caspases in the pathogenesis of muscular damage in obstructed ureters in a rat model.

MATERIALS AND METHODS

Apoptotic cells were detected using in situ end-labelling of DNA fragments. The expression of cytochrome c, and caspases-3, -8 and -9 was examined in 54 rats, using immunohistochemistry.

RESULTS

The severity of ureteric smooth muscle damage increased during obstruction. Apoptotic myocytes, and the expression of cytochrome c and the three caspases in the smooth muscle layer were apparent 14 days after ligation, reaching a peak at 21 days. The numbers of apoptotic cells in the smooth muscle layer correlated significantly with expression of cytochrome c and the three caspases (r = 0.8673, 0.8701, 0.5723 and 0.7910, respectively; all P < 0.01). The expression of cytochrome c in the smooth muscle layer correlated significantly with the expression of the three caspases (r = 0.8234, 0.7558 and 0.7825, respectively; all P < 0.001). The expression of caspase-3 and -8, and -3 and -9 also correlated significantly (r = 0.6721 and 0.8501, respectively; both P < 0.002).

CONCLUSIONS

Cytochrome c and caspases are involved in ureteric myocyte apoptosis; the release of cytochrome c might be important in ureteric damage during obstructive uropathy.

In vitro induction of microglial and endothelial cell apoptosis by cerebrospinal fluids from patients with human African trypanosomiasis

In human African trypanosomiasis, trypanosomes first develop in the blood and lymph (Stage 1), then spread to the central nervous system (CNS) (Stage 2). Disruption of the blood-brain barrier of unknown mechanism occurs in Stage 2 disease. The hypothesis that cerebrospinal fluids (CSF) from African trypanosomiasis patients might contain factor(s) able to induce apoptosis in endothelial cells led us to evaluate this effect by two methods, the TdT-mediated dUTP nick end labelling (TUNEL) method and the measurement of soluble nucleosomes released by apoptotic cells in culture supernatant by ELISA. Apoptosis induction by CSF was also studied with microglial cells, the resident macrophages in the brain, which participate in the blood-brain barrier in the perivascular area. In contrast with control CSF, African trypanosomiasis patients' CSF induced apoptosis in both microglial and endothelial cells. The results obtained with the two methods correlated well, and showed that Stage 2 CSF induced apoptosis at higher levels in microglial cells, whereas the disease stage was not decisive for apoptosis induction in endothelial cells. We measured soluble Fas ligand (sFasL) and anti-Fas antibodies levels, two potent inducers of the Fas signalling pathway leading to apoptosis, in CSF from African trypanosomiasis patients and controls. CSF from African trypanosomiasis patients contained sFasL, and anti-Fas antibodies at higher levels than in controls. Stage 2 CSF contained more sFasL than Stage 1 CSF, and anti-Fas antibodies were detected only in Stage 2 CSF. Caspase-8 inhibitor effect and statistical data suggest that other pro-apoptotic factors may be involved in some CSF-induced apoptosis. Apoptosis induction may participate in the pathogenesis during African trypanosomiasis, and the presence of sFasL and anti-Fas antibodies may provide new tools for diagnosis and prognosis of the disease.

Survivin expression in ovarian carcinoma: correlation with apoptotic markers and prognosis

Survivin is a novel inhibitor of apoptosis commonly detected in tissues during fetal development and in cancer, but not usually in normal tissues. Expression of this protein may be of prognostic significance and therapeutically relevant in many cancers. We assessed survivin expression in ovarian carcinoma, correlating results with expression of other anti-apoptotic (bcl-2, bcl-x, mutant p53) and pro-apoptotic (bax) markers, with prognostic parameters, and prognosis. Paraffin-embedded sections of 49 ovarian carcinoma were immunostained for survivin, bcl-2, bcl-x, bax, and p53. Expression was evaluated in nuclei and cytoplasm, as intensity (0-3+), and percentage of positive cells was scored on a four-tiered system with <10% as negative. Frequency of survivin, bcl-2, bcl-x, bax, and p53 was 73.5%, 36.7%, 93.9%, 77.6%, and 60.4%, respectively. There was significant correlation between nuclear survivin expression and grade (P =.0014), histologic type (P =.0376), and mutant p53 (P =.0414). Survivin expression did not correlate with bcl-2, bcl-x, or bax expression, stage, or overall or disease-free survival. The majority (74%) of ovarian carcinoma show survivin expression, which correlates with poor prognostic parameters (high grade, histologic type, p53 mutation) but not with survival. Therapeutic targeting of survivin in ovarian carcinoma is a future possibility.

Tubular apoptosis in the pathophysiology of renal disease

Apoptosis of renal tubular epithelial cells plays a major role in acute renal failure. Several external and internal signals can induce apoptosis, which is then effectuated via several pathways. These pathways are either the FAS/FAS-L pathway and downstream MAPK (mitogen-activated protein kinases) and JNK (c-Jun N-terminal kinase) signal transduction, or the RANK/RANK-L (receptor activator of NFkB) pathway via activation of the caspase cascade. Other pathways, especially for apoptosis induction by toxins, include the mitochondrial permeability transition pore activation and Bcl-2 superfamily member differential regulation. An important final, irreversible branch of these pathways is the release of cytochrome c from the mitochondria, leading to nuclear fragmentation. Therapeutic interventions of acute tubular injury focus on the prevention of apoptosis by either modulation of the balance of the bcl-2 family or by selectively blocking angiotensin receptors. It is not clear yet, which receptor blockade or combination of receptor blockers are most effective in apoptosis prevention. In chronic renal failure, tubular apoptosis has been found in biopsies from polycystic kidneys, but not in a quantitatively meaningful amount in other chronic human renal diseases. On the other hand, given the short half-life of apoptotic cells of few hours, even low numbers over time might turn out to be important modulators of chronic kidney disease, which are characterized by tubular cell loss. Potential therapeutic interventions to prevent tubular apoptosis in chronic renal disease include angiotensin system inhibition, whereby the angiotensin II AT2 receptor blockade seems more promising in apoptosis inhibition than the inhibition of other receptor subtypes.

Caspase cleavage of the nonstructural protein NS1 mediates replication of Aleutian mink disease parvovirus

Virus-induced apoptosis of infected cells can limit both the time and the cellular machinery available for virus replication. Hence, many viruses have evolved strategies to specifically inhibit apoptosis. However, Aleutian mink disease parvovirus (ADV) is the first example of a DNA virus that not only induces apoptosis but also utilizes caspase activity to facilitate virus replication. To determine the function of caspase activity during ADV replication, virus-infected cell lysates or purified ADV proteins were incubated with various purified caspases. Caspases cleaved the major nonstructural protein of ADV (NS1) at two caspase recognition sequences, whereas ADV structural proteins could not be cleaved. Importantly, the NS1 products could be identified in ADV-infected cells but were not present in infected cells pretreated with caspase inhibitors. By mutating putative caspase cleavage sites (D to E), we mapped the two cleavage sites to amino acid residues NS1:227 (INTD downward arrow S) and NS1:285 (DQTD downward arrow S). Replication of ADV containing either of these mutations was reduced 10(3)- to 10(4)-fold compared to that of wild-type virus, and a construct containing both mutations was replication defective. Immunofluorescent studies revealed that cleavage was required for nuclear localization of NS1. The requirement for caspase activity during permissive replication suggests that limitation of caspase activation and apoptosis in vivo may be a novel approach to restricting virus replication.

Hydrophobic coupling of lipid bilayer energetics to channel function

The hydrophobic coupling between membrane-spanning proteins and the lipid bilayer core causes the bilayer thickness to vary locally as proteins and other "defects" are embedded in the bilayer. These bilayer deformations incur an energetic cost that, in principle, could couple membrane proteins to each other, causing them to associate in the plane of the membrane and thereby coupling them functionally. We demonstrate the existence of such bilayer-mediated coupling at the single-molecule level using single-barreled as well as double-barreled gramicidin channels in which two gramicidin subunits are covalently linked by a water-soluble, flexible linker. When a covalently attached pair of gramicidin subunits associates with a second attached pair to form a double-barreled channel, the lifetime of both channels in the assembly increases from hundreds of milliseconds to a hundred seconds--and the conductance of each channel in the side-by-side pair is almost 10% higher than the conductance of the corresponding single-barreled channels. The double-barreled channels are stabilized some 100,000-fold relative to their single-barreled counterparts. This stabilization arises from: first, the local increase in monomer concentration around a single-barreled channel formed by two covalently linked gramicidins, which increases the rate of double-barreled channel formation; and second, from the increased lifetime of the double-barreled channels. The latter result suggests that the two barrels of the construct associate laterally. The underlying cause for this lateral association most likely is the bilayer deformation energy associated with channel formation. More generally, the results suggest that the mechanical properties of the host bilayer may cause the kinetics of membrane protein conformational transitions to depend on the conformational states of the neighboring proteins.

The protective mechanism of magnolol, a Chinese herb drug, against warm ischemia-reperfusion injury of rat liver

BACKGROUND

Cell apoptosis following warm ischemia-reperfusion injury is a major concern in clinical issues such as organ transplantation, trauma, and cardiogenic shock. The purpose of this study was to evaluate the possible role of magnolol, a Chinese herb drug, in apoptotic injury and the kinetic expression of apoptotic-related genes in rat livers subjected to warm ischemia-reperfusion (WI/R).

MATERIALS AND METHODS

Three weeks prior to the experiment 10 rats underwent a portosystemic shunt operation according to Bengmerk's method. The rats were divided into three groups. Group 1 (GI) was the control group, Group 2 (GII) and Group 3 (GIII) the magnolol-treated groups. GI and GII were subjected to 2 h and GIII to 3 h of WI/R by clamping the portal vein and hepatic artery under ether anesthesia.

RESULTS

Results show that all the control rats died after 2 h WI/R. Apoptotic cells were detected under microscopy as well as by DNA assay. Magnolol-treated groups tolerated warm ischemia-reperfusion for 2 h and significantly less apoptotic cells were observed (198 +/- 22 vs 42.6 +/- 28). But magnolol-treated rats could not tolerate 3 h warm ischemia-reperfusion. RT-PCR of liver tissue shows that there is an upregulated expression of the anti-apoptotic Bcl-xL gene and suppression of the Bcl-xS gene in GII.

CONCLUSION

Magnolol has an anti-apoptotic effect and protects the liver against WI/R for 2 h but not for 3 h through upregulation of the anti-apoptotic Bcl-XL gene and suppression of the Bcl-xS gene.

Apoptosis in leukemia cells is accompanied by alterations in the levels and localization of nucleolin

Molecular defects in apoptotic pathways are thought to often contribute to the abnormal expansion of malignant cells and their resistance to chemotherapy. Therefore, a comprehensive knowledge of the mechanisms controlling induction of apoptosis and subsequent cellular disintegration could result in improved methods for prognosis and treatment of cancer. In this study, we have examined apoptosis-induced alterations in two proteins, nucleolin and poly(ADP-ribose) polymerase-1 (PARP-1), in U937 leukemia cells. Nucleolin is expressed at high levels in malignant cells, and it is a multifunctional and mobile protein that can shuttle among the nucleolus, nucleoplasm, cytoplasm, and plasma membrane. Here, we report our findings that UV irradiation or camptothecin treatment of U937 cells induced apoptosis and caused a significant change in the levels and localization of nucleolin within the nucleus. Additionally, nucleolin levels were dramatically decreased in extracts containing the cytoplasm and plasma membrane. These alterations could be abrogated by pre-incubation with an inhibitor of PARP-1 (3-aminobenzamide), and our data support a potential role for nucleolin in removing cleaved PARP-1 from dying cells. Furthermore, both nucleolin and cleaved PARP-1 were detected in the culture medium of cells undergoing apoptosis, associated with particles of a size consistent with apoptotic bodies. These results indicate that nucleolin plays an important role in apoptosis, and could be a useful marker for assessing apoptosis or detecting apoptotic bodies. In addition, the data provide a possible explanation for the appearance of nucleolin and PARP-1 autoantibodies in some autoimmune diseases.

Necrotic feature of the trophoblasts lacking HLA-G expression in normal and pre-eclamptic placentas

PROBLEM

Human leukocyte antigen (HLA)-G is thought to be expressed in all placental extravillous trophoblasts (EXTs). In pre-eclamptic placentas, a lack of HLA-G expression on EXTs had been found, and deduced as a possible cause of pre-eclampsia. However, a subset of EXTs lacking expression of HLA-G can also be found in normal placenta. Therefore, we sought to compare these cells in normal and pre-eclamptic placentas.

METHODS OF STUDY

Frozen sections of normal and pre-eclamptic placentas were examined by immunohistochemical staining using HLA-G monoclonal antibody 87G, histochemical enzymatic analysis of succinate dehydrogenase (SDH) and ultrastructural analysis.

RESULTS

A subset of EXTs lacking HLA-G expression was found in both normal and pre-eclamptic placentas. These cells showed necrotic features such as the swelling of cells, eosin-achromatophilia, the loss of SDH activity and swelling mitochondria. Cells from both tissues were identical with regard to these features.

CONCLUSION

The features of the EXTs lacking HLA-G expression indicated they had undergone necrosis and thus could not express HLA-G protein. Therefore, an alternative interpretation to the lack of HLA-G expression in pre-eclamptic placentas is that it is the result of cell death and not the cause.

Proapoptosis and antiapoptosis-related molecules during postnatal pancreas development in control and nonobese diabetic mice: relationship with innervation

The mouse pancreas, an immature organ at birth, reaches its adult size and morphology after weaning (3 weeks of age). Around this time, apoptotic phenomena and various types of macrophages are normally present. During development, Fas-Fas ligand (FasL) interactions are known to play a role in apoptotic events involved in tissue remodeling and elimination of damaged cells, and macrophages are routinely observed near apoptotic cells. Apoptosis and Fas-FasL interactions are also thought to be involved in the pathogenesis of autoimmune diseases, particularly type 1 diabetes (T1D). Therefore, we used early postnatal mouse pancreata from three control strains (C57BL/6, DBA/2, BALB/c) and from two strains with the nonobese diabetic (NOD)-related genetic background (the spontaneous T1D NOD model and the lymphocyte-deficient NODscid strain) to study apoptotic phenomena together with the molecular and immunohistochemical expression of proapoptosis (Fas, FasL) and antiapoptosis (Bcl-2) proteins. First, although no major difference in the numbers of total pancreatic apoptotic cells was noted among strains, significantly more FasL(+) expression was detected immunohistochemically in mice with the NOD genetic background than in control pancreata from birth to 1 month of age. Second, FasL(+), Fas(+), and Bcl-2(+) structures seemed to be associated with innervation, regardless of the strain and age. Third, in control and NOD strains, nerves (identified by immunohistochemical labeling of peripherin or neurofilament 200), were often observed in periductular and peri-insular areas. Finally, some peripherin-positive nerves expressed the interferon-inducible protein-10 chemokine, and various types of macrophages were found to be in close proximity. These data highlight an overlooked, innervation-related aspect of normal mouse postnatal pancreas development with possible implications in T1D pathogenesis.

Chromium(III)-induced apoptosis of lymphocytes: death decision by ROS and Src-family tyrosine kinases

Apoptosis is an active process induced by a variety of physiological and external stimuli, in which elimination of damaged cells are effected through a genetically controlled process. In this study, we have examined the mechanism of chromium(III) [Cr(III)]-induced cytotoxicity with respect to its relationship to oxidative stress. Morphology, flow cytometry, and DNA fragmentation studies show that tris-(1,10-phenanthroline)chromium(III) [Cr(III)-phen], tris-(2,2'-bipyridyl)chromium(III) [Cr(III)-bpy], trans-diaqua[1,2-bis(salicylideneamino)ethanechromium(III)] [Cr(III)-salen], and trans-diaqua[1,3-bis(salicylideneamino)propanechromium(III)] [Cr(III)-salprn] induced apoptosis of lymphocytes. Pentaammineaquachromium(III) [Cr(III)-hpa] does not induce apoptosis. Apoptosis induced by these complexes involves the generation of reactive oxygen species (ROS) as seen by increased fluorescence of dichloroflourescein (DCF) observed through flow cytometry. Pretreatment of lymphocytes with antioxidants completely abrogate apoptosis. Cr(III) treatment also increased the expression and activation of Src-family tyrosine kinases viz. p56lck, p59fyn, and p53/56lyn, as seen by immunoblotting and immune complex kinase assay. PP2, a selective Src-family tyrosine kinase inhibitor, abolishes apoptosis, indicating that Src-family tyrosine kinases are directly involved in eliciting apoptosis. Interestingly, a one-to-one correlation between the expression of Src-family tyrosine kinases and ROS is observed, since antioxidants pretreatment inhibits the expression and the activation of these kinases. These results further indicate that Cr(III)-induced apoptosis is mediated through production of ROS, which in turn activates the Src-family tyrosine kinases. The increased activation of Src-family tyrosine kinases may be a mechanism involved in apoptosis of lymphocytes elicited by various other physiological stimuli that exploit ROS as a second messenger.

Immune reconstitution following hematopoietic stem-cell transplantation

BACKGROUND

Reconstitution of the immune system following allogeneic stem-cell transplantation is a complex process that requires successful engraftment of the hematopoietic stem cell, as well as adequate thymic function. As the majority of patients have reduced thymic function due to age, hormonal changes, as well as the damage caused by conditioning and GvHD, immune recovery is often delayed and incomplete. Following graft infusion there is rapid proliferation of natural killer (NK) cells that appear to proceed directly from the hematopoietic stem cell. B-cell function is dependent on specific maturation development in the BM micro-environment, as well as CD4 help. The CD8 population expands rapidly due to proliferation of many memory cells that react against Class I Ags, as well as viral molecules. Expansion of T-helper cells originates mainly from the memory pool that is present in the bone marrow graft. Naive cells require competent thymus hence the CD4 cell counts may be subnormal with clinical immunodeficiency. Controversy remains as to the capacity of the thymus to recover and thus extra thymic proliferation of T cells have been postulated. However these cells appear to have a limited capacity to expand and a fixed repertoire.

DISCUSSION

Donor lymphocyte infusions may contribute a competent CD4 population that can cause GvHD, but have limitations in the capacity to respond to new antigens. Future research needs to be concentrated on improving the capacity of the thymus to reconstitute a functional naive population.

Molecular and cellular basis of pulmonary vascular remodeling in pulmonary hypertension

Clinical pulmonary hypertension is characterized by a sustained elevation in pulmonary arterial pressure. Pulmonary vascular remodeling involves structural changes in the normal architecture of the walls of pulmonary arteries. The process of vascular remodeling can occur as a primary response to injury, or stimulus such as hypoxia, within the resistance vessels of the lung. Alternatively, the changes seen in more proximal vessels may arise secondary to a sustained increase in intravascular pressure. To withstand the chronic increase in intraluminal pressure, the vessel wall becomes thickened and stronger. This "armouring" of the vessel wall with extra-smooth muscle and extracellular matrix leads to a decrease in lumen diameter and reduced capacity for vasodilatation. This maladaptive response results in increased pulmonary vascular resistance and consequently, sustained pulmonary hypertension. The process of pulmonary vascular remodeling involves all layers of the vessel wall and is complicated by the finding that cellular heterogeneity exists within the traditional compartments of the vascular wall: intima, media, and adventitia. In addition, the developmental stage of the organism greatly modifies the response of the pulmonary circulation to injury. This review focuses on the latest advances in our knowledge of these processes as they relate to specific forms of pulmonary hypertension and particularly in the light of recent genetic studies that have identified specific pathways involved in the pathogenesis of severe pulmonary hypertension.

Developmental- and tissue-specific expression of an inhibitor of apoptosis protein 1 homologue from Aedes triseriatus mosquitoes

We have identified a homologue of the Drosophila inhibitor of apoptosis protein 1 in Aedes triseriatus mosquitoes (designated AtIAP1). The AtIAP1 gene maps to a single locus on chromosome 2. The translation product is a 403 amino acid protein that contains two baculovirus IAP repeat (BIR) domains and a RING finger motif. AtIAP1 mRNA was detectable by RT-PCR amplification in all the mosquito developmental stages (embryos, first-fourth instar larvae, early and late pupae, adults) and adult tissues (midguts, ovaries) examined. In contrast, immunoblots with AtIAP1-specific antibodies revealed that the protein was detectable only in certain developmental stages (first instar larvae, early pupae, adults) and tissues (ovaries). AtIAP1-specific serum also recognized proteins in Ae. aegypti, Ae. albopictus and Culex tritaeniorhynchus. Immunoblot analysis revealed that similar amounts of IAP1 were expressed in LaCrosse virus infected and uninfected Ae. albopictus cell cultures.

Positive inotropic stimulation

Adrenergic receptors transduce signals through the G proteins to regulate cardiac function. The catecholamines, via alpha- and beta-adrenergic receptor (beta-AR) stimulation, may play a role in the development of heart failure. Norepinephrine and isoproterenol can induce cardiac myocyte apoptosis. Studies suggest that alpha-, beta1-, and beta2-adrenergic pathways differentially regulate cardiac myocyte apoptosis. The stimulation of beta1-AR leads to cyclic AMP-dependent apoptosis, whereas that of the beta2-AR elicits concurrent apoptosis and survival signals in cardiac myocytes coupled to Gs protein. Overexpression of alpha1-adrenergic receptors does not induce apoptosis in wild-type mice. In contrast, the heart failure observed in some murine models has to be related to an enhanced beta-AR kinase expression. These recent advances make it possible to understand the beneficial effects of beta-blockers in the treatment of chronic heart failure and provide novel therapeutic modalities through the stimulation of beta2-ARs or the inhibition of beta-AR kinase expression.

DUG is a novel homologue of translation initiation factor 4G that binds eIF4A

To elucidate the molecular mechanisms of cell death, we have cloned a new gene, designated death-upregulated gene (DUG), from rat insulinoma cells. DUG is constitutively expressed at very low levels in normal cells but is dramatically upregulated in apoptotic cells following serum/glucose starvation or death receptor ligation by Fas ligand. The DUG mRNA is present in two splicing forms: a long form that encodes a protein of 469 amino acids and a short form that gives rise to a polypeptide of 432 amino acids. The predicted DUG protein sequence contains two putative nuclear localization signals and multiple phosphorylation sites for protein kinases and two conserved MA3 domains. Importantly, DUG is homologous to eukaryotic translation initiation factor (eIF) 4G and binds to eIF4A presumably through MA3 domains. Upon transfection, DUG inhibits both intrinsic and extrinsic pathways of apoptosis. Thus, DUG is a novel homologue of eIF4G that regulates apoptosis.

Morphological and biochemical aspects of apoptosis, oncosis and necrosis

Recent investigations have demonstrated the need for a precise differentiation of various forms of cell death such as apoptosis, oncosis, necrosis and programmed cell death. Apoptosis is marked by cellular shrinking, condensation and margination of the chromatin and ruffling of the plasma membrane with eventually breaking up of the cell in apoptotic bodies. Cell death marked by cellular swelling should be called oncosis, whereas the term necrosis refers to the morphological alterations appearing after cell death. Apoptosis and oncosis are therefore pre-mortal processes, while necrosis is a post-mortal condition. The term programmed cell death refers to the 'fixed' pathway followed by dying cells, whether or not with the characteristic morphology of apoptosis. Three mechanisms are actually known to be involved in the apoptotic process: a receptor-ligand mediated mechanism, a mitochondrial pathway and a mechanism in which the endoplasmic reticulum plays a central role. All three mechanisms activate caspases which are responsible for the characteristic morphological changes observed during apoptosis. A review of the different methods used for detecting apoptotic cells demonstrates that most of these techniques are not entirely specific.

Apoptosis induced by culturing MH134 cells in the presence of porcine skin gelatin in vitro

Porcine skin (PS) gelatin showed antitumor effect in vitro on MH134 murine hepatoma cells. We analyzed the effect of PS gelatin on MH134 cells compared to the effect of Bovine bone (BB) gelatin, 5-Fluorouracil (5-FU) and 7-ethyl-10-hydroxycamptothecin (SN-38). We previously suggested that PS gelatin induces apoptosis in MH134 cells using flow cytometric analysis. We performed agarose gel electrophoresis and electron microscopic studies to ascertain apoptosis. Agarose gel electrophoresis showed the typical DNA ladder pattern and electron microscopic findings revealed characteristic features in the case of apoptosis on PS gelatin. SN-38 also showed DNA ladder pattern and ultrastructural changes in apoptosis. 5-FU didn't show DNA ladder pattern but electron microscope revealed changes in necrosis. On the other hand, BB gelatin didn't induce apoptosis or necrosis.

Nip21 gene expression reduces coxsackievirus B3 replication by promoting apoptotic cell death via a mitochondria-dependent pathway

Our previous studies, using differential mRNA display, suggested that the mouse Nip21 gene may be involved in myocarditis development in the coxsackievirus B3 (CVB3)-infected mouse heart. Sequence comparison indicated that the mouse Nip21 gene shares high sequence homology to human Nip2. This human protein is known to interact with both the apoptosis inhibitor Bcl-2 and a homologous protein, the adenovirus E1B 19-kDa protein. Such interactions implicate Nip21 gene in cell death pathways. To study the function of this gene, we have cloned Nip21 from mouse hearts and established a Tet-On doxycycline-inducible HeLa cell line and a cardiomyocyte H9c2 cell line expressing Nip21 to characterize gene function in relation to apoptosis. We demonstrated that Nip21 expression could induce apoptosis via caspase-depended mitochondria activation. To further determine the function of Nip21 in CVB3-induced apoptosis, the Tet-On/Nip21 HeLa cell line was induced by doxycycline followed by CVB3 infection. We found that activation of caspase-3 and cleavage of poly-(ADP-ribose) polymerase occurred 2 hours earlier than in vector-transfected control cells, suggesting that Nip21 expression enhances CVB3-induced apoptosis. We also demonstrated a significant decrease in HeLa cell and H9c2 cell viability. Particularly, as illustrated by viral plaque assay, CVB3 replication was dramatically reduced in Tet-On HeLa cells, due at least in part to the earlier killing of the host cells by Nip21 overexpression.

Comparison of automated haematology analysers for detection of apoptotic lymphocytes

Automated haematology analysers can rapidly provide accurate blood cell counts and white blood cell differentials. In this study, we evaluated four different haematology analysers for the detection of apoptotic lymphocytes in peripheral blood: MAXM A/L Retic, H*2, Cell-Dyn 3500 and NE-8000. With the MAXM A/L Retic haematology analyser, the apoptotic lymphocyte cluster appeared below the original lymphocyte cluster on the volume/DF1, and to the right under the original lymphocyte cluster on the volume/DF2 scattergrams. With the H*2 haematology analyser, the apoptotic polymorphonuclear lymphocytes produced a higher lobularity index on the BASO channel. With the Cell-Dyn 3500 haematology analyser, the apoptotic lymphocyte cluster appeared to the right side of the original lymphocyte cluster on the 0D/10D scattergram and to the left side of the polymorphonuclear cluster on the 90D/10D scattergram. With the NE-8000 haematology analyser, the apoptotic lymphocyte cluster was not distinguishable. Thus, apoptotic lymphocytes are readily detected on scattergrams generated by selected haematology analysers.

Acute renal failure in endotoxemia is caused by TNF acting directly on TNF receptor-1 in kidney

Bacterial endotoxin (LPS) is responsible for much of the widespread inflammatory response seen in sepsis, a condition often accompanied by acute renal failure (ARF). In this work we report that mice deficient in TNFR1 (TNFR1(-/-)) were resistant to LPS-induced renal failure. Compared with TNFR1(+/+) controls, TNFR1(-/-) mice had less apoptosis in renal cells and fewer neutrophils infiltrating the kidney following LPS administration, supporting these as mediators of ARF. TNFR1(+/+) kidneys transplanted into TNFR1(-/-) mice sustained severe ARF after LPS injection, which was not the case with TNFR1(-/-) kidneys transplanted into TNFR1(+/+) mice. Therefore, TNF is a key mediator of LPS-induced ARF, acting through its receptor TNFR1 in the kidney.

Towards a biological characterization of focal segmental glomerulosclerosis

The primary form of focal segmental glomerulosclerosis (FSGS) has become one of the most common causes of end-stage renal disease in children and adolescents. FSGS was initially considered to be the histological expression of a single disease entity. However, evidence accumulated during the past four decades indicates that FSGS is heterogeneous in nature. It therefore is not surprising that the many therapeutic combinations and permutations that have been tried have yielded variable results in different hands. This has generated substantial confusion and frustration among physicians and patients alike. Recent progress in genetics and molecular biology has opened promising new vistas of investigation. Identification of genes that control components of the glomerular capillary, proteins that form the structural basis of podocytes, and genetic mutations that affect the integrity of these structures has revolutionized our understanding of the glomerular filtration barrier. Substantial progress also has been made in understanding the mechanisms that lead to progression of renal disease and, ultimately, sclerosis. Studies of these factors are likely to yield a mechanistic-based classification of FSGS that will allow us to design therapeutic regimens suited to specific subtypes of this disease.

Caspase activation is required for permissive replication of Aleutian mink disease parvovirus in vitro

Aleutian mink disease parvovirus (ADV) is distinct among the parvoviruses as infection in vivo is persistent, restricted, and noncytopathic. In contrast, infections with other more prototypic parvoviruses, like mink enteritis virus (MEV), are acute, cytopathic, and characterized by permissive replication in vivo. Although apoptosis results in the death of cells acutely infected by parvoviruses, the role of apoptosis in ADV infections is unknown. Permissive infection of ADV resulted in apoptosis of Crandell feline kidney (CrFK) cells as indicated by TUNEL staining, Annexin-V staining, and characteristic changes in cell morphology. Pretreatment of infected cells with caspase 3 or broad-spectrum caspase inhibitors prevented apoptosis. In addition, treatment of infected cells with these inhibitors caused a 2 log(10) reduction in the yield of infectious virus compared to untreated cultures. This block in replication preceded substantial viral DNA amplification and gene expression. However, inhibitors of caspases 1, 6, and 8 did not have this effect. MEV also induced caspase-dependent apoptosis following infection of CrFK cells, although production of infectious progeny was not affected by inhibition of apoptosis. Thus, permissive replication of ADV in vitro depended upon activation of specific caspases. If ADV infection of cells in vivo fails to initiate caspase activation, the requirement of caspase activity for replication may not be met, thus providing a possible mechanism for persistent, restricted infection.

Pharmacological treatment of traumatic brain injury: a review of agents in development

Successful treatment strategies for patients with traumatic brain injury (TBI) remain elusive despite standardised clinical treatment guidelines, improved understanding of mechanisms of cellular response to trauma, and a decade of clinical trials aimed at identifying therapeutic agents targeted at mediators of secondary injury. The information explosion relative to mechanisms of secondary injury has identified several potential targets for intervention. Depending on the type of injury to the brain and the intensity and the success of resuscitation, necrosis, apoptosis, inflammatory and excitotoxic cellular damage can be seen. These same processes may continue postinjury, depending on the adequacy of clinical care. Each of these mechanisms of cellular damage can initiate a cascade of events mediated by endogenous signals that lead to secondary neurological injury. Several factors contributed to the failure of earlier clinical trials. Now that these have been recognised, a positive impact on future drug development in TBI has been realised. Both the US and Europe have organised brain injury consortiums where experts in the treatment of TBI provide insight into study design, implementation, conduct and oversight in conjunction with the pharmaceutical industry. Consequently, future clinical trials of new investigational treatments have greater potential for identifying therapies of merit in specific populations of patients with TBI. Pharmacological strategies under investigation are targeting sites involved in the secondary cascade that contribute to overall poor outcome following the primary injury. These treatments include ion channel antagonists including calcium channel antagonists, growth factors, antioxidants, stem cells, apoptosis inhibitors, and inhibitors of other signal modulators. In conclusion, the complexity of TBI pathology and the mechanisms contributing to secondary injury present unique therapeutic challenges. Appropriate research targets for intervention continue to be investigated, however, the likelihood of improving outcomes with a single approach is extremely small. There is a need for collaborative efforts to investigate the optimal time for drug administration and the logical sequence or combination of treatments that will ultimately lead to improved neurological outcomes in this population.

Apoptosis: life through planned cellular death regulating mechanisms, control systems, and relations with thyroid diseases

Apoptosis is an active biologic process that represents a form of programmed cellular suicide, activated either by genetic factors or by cellular lesions caused by various extracellular traumatic agents. The alterations of its functional mechanisms control cellular homeostasis are involved in the genesis of many illnesses. There are different control systems that can both stimulate and inhibit apoptosis, such as the p53 and Bcl-2 proteins. Different injuries may cause a rapid increase in the levels of p53 and the activation of the complex mechanism which leads either to damage repair or cellular apoptosis. The concept of tumor growth as a dynamic balance between cellular development and death is well applicable to differentiated thyroid carcinomas, which are generally not highly invasive and present excellent prognosis. On the contrary, in aggressive anaplastic thyroid carcinoma there is an increase in p53, whereas in normal thyroid cells there is a high expression of Bcl-2, so as to interfere with apoptosis when physiologic hormone levels are normal. However, only some of the biomolecular mechanisms behind the genesis of thyroid tumors have been explained, and the role of apoptosis in thyroid diseases has not been well defined. This review provides information about relationship between apoptosis and thyroid diseases.

Kinetics of apoptotic markers in exogeneously induced apoptosis of EL4 cells

We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membrane changes in correlation to DNA fragmentation and cell shrinkage. We applied three apoptosis inducers (staurosporine, tubericidine and X-rays) and we looked at various markers to follow the early-to-late apoptotic events: phospholipid translocation (identified through annexin V-fluorescein assay and propidium iodide), lipid package (via merocyanine assay), membrane fluidity and anisotropy (via fluorescent measurements), DNA fragmentation by the fluorescence-labeling test and cell size measurements. The different apoptotic inducers caused different reactions of the cells: staurosporine induced apoptosis most rapidly in a high number of cells, tubercidine triggered apoptosis only in the S phase cells, while X-rays caused a G2/M arrest and subsequently apoptosis. Loss of lipid asymmetry is promptly detectable after one hour of incubation time. The phosphatidylserine translocation, decrease of lipid package and anisotropy, and the increase of membrane fluidity appeared to be based on the same process of lipid asymmetry loss. Therefore, the DNA fragmentation and the cell shrinkage appear to be parallel and independent processes running on different time scales but which are kinetically inter-related. The results indicate different signal steps to apoptosis dependent on inducer characteristics but the kinetics of "early-to-late" apoptosis appears to be a fixed program.

In vivo monitoring of therapy-induced apoptotic process in patients with chronic lymphocytic leukemia and acute non-lymphoblastic leukemia

BACKGROUND: The level of spontaneous apoptosis, the maximal response by apoptosis and the time when maximal apoptotic response is established are significant prognostic parameters that correlate with the therapeutic response of patients with malignant diseases. METHODS: Our study included 12 patients with B-CLL (I group of 7 patients) and ANLL (II group of 5 patients). Detection of apoptotic parameters on semifine section of peripheral blood was performed. Bcl 2 and mutated p53 expression were analyzed using the monoclonal antibodies by APAAP techniques. RESULTS: In our work, the established levels of spontaneous and therapy induced apoptosis correlate with clinical response of patients. All patients were bcl 2 strongly positive. Expression of p53 protein was not detected in these patients. The ultra structural analysis of the malignant cells has shown that a great number of cells react to antineoplastic agents? effect either by activating the cell response to stress or by apoptosis. CONCLUSION: The results of our pilot study have shown that the established levels of spontaneous and therapy induced apoptosis are in correlation with the clinical response of the patients to the applied therapy and that the measurable apoptotic parameters can represent prognostic parameters in treatment of hematologic neoplasms.

Significantly depressed percentage of CD27+ (memory) B cells among peripheral blood B cells in patients with primary Sjögren's syndrome

CD27 has been found to be expressed on somatically mutated B cells and is thus a positive marker for memory B cells in peripheral blood (PB). Since abnormal immunogloblin (Ig) production is characteristic of the autoimmune diseases primary Sjögren's syndrome (pSS) and rheumatoid arthritis (RA), we have analyzed in detail the CD27 expression on PB B cell from these patient groups. Staining of PB B cells with monoclonal antibodies (MoAb) specific for CD19 and CD27 revealed a significantly depressed percentage of CD27+ PB B cells in patients with pSS (14.8 +/- 1.6%) compared to both healthy donors (31.3 +/- 4.7%, P = 0.005) and patients with RA (40.8 +/- 4.1%, P = 0.0001). In addition, the percentages of both the IgD+CD27+ and the IgD-CD27+ B-cell subpopulations were significantly lower in pSS patients compared to RA patients and healthy donors. However, the relative proportion of IgD- and IgD+ cells among the CD27+B cells were almost the same for the three groups. Our data suggest a disturbance in the differentiation of peripheral B cells and possibly a bias towards plasma cell differentiation, resulting in a depressed percentage of CD27+ memory PB B cells in pSS. These results are potentially of pathological significance and of diagnostic value.

Anti-Fas-induced apoptosis in chondrocytes reduced by hyaluronan: evidence for CD44 and CD54 (intercellular adhesion molecule 1) invovement

OBJECTIVE

To investigate the in vitro effect of therapeutic hyaluronan (HA) of 500-730 kd on anti-Fas-induced apoptosis of chondrocytes from osteoarthritis (OA) patients, and to assess its mechanism of action by analyzing the role of the 2 HA receptors, CD44 and CD54 (intercellular adhesion molecule 1 [ICAM-1]).

METHODS

Chondrocytes isolated from human OA knee cartilage were cultured and the effect of HA on both spontaneous and anti-Fas-induced apoptosis was evaluated. Apoptosis was analyzed by JAM test (for quantitative analysis of fragmented DNA), cell death detection immunoassay (for quantitative analysis of oligonucleosome), TUNEL assay, and electron microscopy. Blocking experiments with anti-CD44 and anti-CD54 alone or in combination were performed to investigate the HA mechanism of action.

RESULTS

Both quantitative tests demonstrated that anti-Fas significantly induced apoptosis of isolated OA chondrocytes. HA at 1,000 microg/ml significantly reduced the anti-Fas-induced apoptosis of chondrocytes but did not affect spontaneous chondrocyte apoptosis. These data were also confirmed by TUNEL staining and by electron microscopy morphologic evaluation. The antiapoptotic effects of HA on anti-FAS-induced chondrocyte apoptosis were significantly decreased by both anti-CD44 (mean +/- SD 57 +/- 12% inhibition) and anti-ICAM-1 (31 +/- 22% inhibition). The mixture of the 2 antibodies had an additive effect, since the rate of inhibition increased to 87 +/- 13%.

CONCLUSION

These data demonstrate that 500-730-kd HA exerts an antiapoptotic effect on anti-FAS-induced chondrocyte apoptosis by binding its specific receptors (CD44 and ICAM-1). Furthermore, this HA fraction may be able to slow down chondrocyte apoptosis in OA by regulating the processes of cartilage matrix degradation.

Renal cell apoptosis in chronic obstructive uropathy: the roles of caspases

BACKGROUND

Apoptosis of tubular and interstitial cells is well documented in kidneys with chronic obstructive uropathy (COU) and probably plays an important role in the pathogenesis of this condition. The molecular control of apoptosis in COU remains poorly understood. Apoptosis in general is known to proceed initially along distinct pathways, which later converge into a common arm characterized by orderly activation of caspases. Caspases are cytosolic enzymes that belong to a 12-member family and serve as effector molecules for apoptosis. The role of individual caspases in mediating renal cell apoptosis in kidneys with COU is studied.

METHODS

Kidneys were harvested from sham-operated mice and mice with COU created by left ureter ligation at days 4, 7, 15, 20, and 30. The following studies were performed: (1) determination of dried kidney weight; (2) in situ end labeling of fragmented DNA to detect apoptotic tubular and interstitial cells; (3) ribonuclease protection assay with specific anti-sense RNA probes for caspases 1, 2, 3, 6, 7, 8, 9, 11, and 12 to detect the expression of individual caspases; (4) immunostaining for caspases; and (5) assay for caspase 3. To assess the role of caspases in COU-associated renal cell apoptosis, the frequencies of apoptotic tubular and interstitial cells were separately quantitated for each experimental time point, and their patterns of variation were correlated with those of individual caspases.

RESULTS

The obstructed kidneys showed progressive tissue loss (60% of control at day 15). Apoptosis of both tubular and interstitial cells was seen in obstructed kidneys. Tubular cell apoptosis peaked at four days after ureter ligation (13-fold of control), remained high between days 4 to 15, and thereafter decreased rapidly. Apoptotic interstitial cells were scanty initially, but gradually increased throughout the entire experiment. Apoptosis was minimal throughout the experiment in control and contralateral kidneys. In control and contralateral kidneys, caspases 2, 3, 6, 7, 8, and 9 mRNAs were expressed at low levels, whereas those for caspases 1, 11, and 12 were not detected. The obstructed kidneys displayed increased expression of all tested caspases. Caspases 1, 11, and 12 mRNAs were detected in obstructed kidneys in a common pattern characterized by a sharp increase at day 4, followed by a decrease until day 20, and a subsequent sharp increase until the end of the study at day 30. A similar pattern was noted for other caspases (2, 3, 6, 7, 8, and 9), which maximally reached twofold to fourfold that of controls. Immunostaining for caspases 1, 2, 3, 6, 7, 8, and 9 showed the same pattern characterized by focal and weak expression in proximal tubules of control or contralateral kidney, contrasting with increased staining in atrophic or dilated tubules of obstructed kidneys. Interstitial cells also displayed staining for several caspases, which paralleled the increasing density of interstitial cells toward the end of the experiment. Caspase-3 assay showed a marked increased activity in obstructed kidneys that reached fourfold and sevenfold of control at days 4 and 30, respectively. The rise and fall of caspase mRNAs between days 4 and 30 paralleled a similar fluctuation in tubular cell apoptosis. The subsequent increase of mRNAs was correlated with a continuous rise of interstitial cell apoptosis.

CONCLUSIONS

Urinary obstruction in mice induces apoptosis of both tubular and interstitial cells in the affected kidney in a distinctive pattern that parallels an increased expression of caspases. This correlation suggests that these caspases mediate COU-associated renal cell apoptosis. Among the evaluated caspases, increased renal caspase 3 activity implies its central role in renal cell apoptosis associated with urinary obstruction.