Genetics of programmed cell death and proliferation

Vascular remodeling and hypertrophy-hyperplasia of the heart and kidney are the hallmarks of hypertensions, being involved in the long-term maintenance of elevated blood pressure and the development of cardiovascular and renal hypertension. Both augmented proliferation and unscheduled programmed cell death (apoptosis) contribute to this phenomenon. In the present article, we summarize the results of these studies with an emphasis on the relative impact of genetic determinants and the environment.     

The Nobel Prize 2002. Organ development and programmed cell death

Der Nobelpreis für Medizin geht in diesem Jahr an die britischen Molekularbiologen Sidney Brenner und John Sulston sowie an ihren US-amerikanischen Kollegen Robert Horvitz (Abb.1). Die drei Wissenschaftler erhalten die Auszeichnung für ihre Forschungsarbeiten zur genetischen Regulierung der Organentwicklung und des programmierten Zellsterbens. Ihre jahrzehntelange Erforschung dieser Prozesse bei dem Nematoden Caenorhabditis elegans lieferte nicht nur wichtige Erkenntnisse für die Grundlagenforschung, sondern er?ffnete ebenfalls neue Einblicke in die Entstehungsbedingungen und Behandlungsm?glichkeiten verschiedener Krankheiten. B.Knapp Springer-Verlag,Tiergartenstr.17, 69121 Heidelberg     

肺缺血/再灌注损伤与程序性细胞死亡

肺缺血／再灌注损伤（pulmonary ischemia reperfusion injury，PIRI）在临床工作中时有发生，并且后果非常严重。最近研究表明程序性细胞死亡（pmgmmmed cell death，PCD）在其中起着重要的作用。与细胞坏死一样，PCD对肺组织造成严重的危害。有效地预防PCD的发生，将会增加PIRI的治愈率。     

细胞程序性死亡在骨质疏松症中的研究进展

骨质疏松症(osteoporosis, OP)是多种病理因素导致的全身性骨代谢疾病。近来年，因高发病率、致残率及尚未明确的发病机制使其成为全球关注的公共健康问题。过去普遍认为细胞凋亡是唯一受调控的细胞死亡方式，细胞坏死不受调控。随着现代分子生物学技术的不断发展，发现细胞坏死亦可被某些基因和蛋白通路调控。凋亡、坏死性凋亡、铁死亡和焦亡等均属于细胞程序性死亡(programmedcelldeath, PCD),其是生物发育和病理特征的重要组成部分。PCD可影响骨代谢微环境及骨代谢平衡，在OP的发生发展中具有重要作用，笔者就上述细胞程序性死亡方式与OP的相关研究进行综述，以期为OP的防治提供新策略。     

Treatment with nimodipine or mannitol reduces programmed cell death and infarct size following focal cerebral ischemia

The present study was conducted to evaluate the effects of nimodipine and mannitol on infarct size and on the amount of apoptosis after transient focal cerebral ischemia. Focal cerebral ischemia was induced in male Sprague-Dawley rats (weight 300–380 g) by transient occlusion of the right middle cerebral artery (MCAO) using an intraluminal thread model. All animals underwent ischemia for 2 h, followed by 24 h of reperfusion. Group I (n=16) was untreated. Group II (n=16) received 15% mannitol (1 g/kg as bolus) and group III (n=9) received 15 μg/kg/h nimodipine intravenously beginning 15 min prior to MCAO. Twenty-four hours after reperfusion, the brain was taken and sectioned in coronal slices. The slices were stained with H&E and with the transferase dUTP nick-end labeling (TUNEL) technique. Histopathological analysis revealed a significant (P<0.05) decrease in infarct size in the striatum with both drugs: mannitol (group II) 25.4±5.9% and nimodipine (group III) 21.5±11.0% versus control (group I) 34.9±7.0% and in the cortex 2.7±2.0% (group II) and 6.3±2.4% (group III) versus control 14.4±9.0% (group I). The number of apoptotic cells was statistically lower in the therapy groups (group III 9.6, group II 25.8) versus control (group I 57.9) (Mann-Whitney-Wilcoxon U-test Z>1.96, P<0.05). This study indicates that mannitol and nimodipine provide neuroprotection by preventing both the necrotic and apoptotic components of cell death after transient focal cerebral ischemia and may be effective as neuroprotective drugs for cerebrovascular surgery. Received: 23 March 2000 / Accepted: 10 April 2000     

Research progress regarding programmed cell death 1/programmed cell death ligand 1 inhibitors combined with targeted therapy for treating hepatocellular carcinoma

In recent years, a number of targeted therapeutic agents have achieved success in phase III trials in patients with advanced hepatocellular carcinoma (HCC), including sorafenib, lenvatinib, and regorafenib. Immunotherapy is considered to be an effective treatment for advanced HCC. Immune checkpoint inhibitors targeting programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) are important antitumor immunotherapy agents that represent breakthroughs in the treatment of advanced HCC. However, treating advanced HCC is still a great challenge, and the need for new treatments remains urgent. This review briefly summarizes the research progress in the use of PD-1/PD-L1 inhibitors combined with targeted therapy for treating HCC.     

Relationship between DNA fragmentation and apoptosis in the programmed cell death in the rat prostate following castration

Previous studies have demonstrated that the rapid involution of the rat ventral prostate following castration involves the death of the androgen-dependent epithelial cells present within the gland and that this death is the result of a series of discrete biochemical steps. The degradation of genomic DNA into nucleosomal-sized fragments is an early event in this process and is catalyzed by calcium magnesium-dependent endonuclease activity. The morphologic correlation of the involution process involves a series of structural changes which are collectively referred to as apoptosis. The apoptotic process describes the earliest apparent signs of morphologic change exhibited by the dying cells through their eventual complete destruction and deletion from the tissue. The temporal relationship between these recently described biochemical events and the morphologic changes of the apoptotic process were compared in the present study, in order to test the cause versus effect nature of DNA fragmentation in the programmed death of androgen dependent prostatic cells following castration. These studies demonstrated that the early elevation of the Ca+2 Mg+2-dependent endonuclease activity and the fragmentation of DNA into nucleosomal oligomers occurs within prostatic glandular epithelial cells and probably does not involve the direct participation of extraprostatic cells which may subsequently migrate into the gland. Once the DNA is initially cleaved into the nucleosomal oligomers, the subsequent participation of lysosomal enzymes act in a less restricted fashion to degrade both the nucleosomal DNA as well as the cytoplasmic elements and the cell becomes morphologically apoptotic. As the elevations in Ca+2 Mg+2-dependent endonuclease activity and DNA fragmentation are initiated at a time well before the cell is morphologically dead, as defined by apoptosis, these changes in DNA metabolism must not be the consequences of cell death but instead are early causal events in an active process of programmed cell death.     

Control of programmed cell death by distinct electrical activity patterns

Electrical activity and sufficient supply with survival factors play a major role in the control of apoptosis in the developing cortex. Coherent high-frequency neuronal activity, which efficiently releases neurotrophins, is essential for the survival of immature neurons. We studied the influence of neuronal activity on apoptosis in the developing cortex. Dissociated cultures of the newborn mouse cerebral cortex were grown on multielectrode arrays to determine the activity patterns that promote neuronal survival. Cultures were transfected with a plasmid coding for a caspase-3-sensitive fluorescent protein allowing real-time analysis of caspase-3-dependent apoptosis in individual neurons. Elevated extracellular potassium concentrations (5 and 8 mM), application of 4-aminopyridine or the γ-aminobutyric acid-A receptor antagonist Gabazine induced a shift in the frequency distribution of activity toward high-frequency bursts. Under these conditions, a reduction or delay in caspase-3 activation and an overall increase in neuronal survival could be observed. This effect was dependent on the activity of phosphatidylinositol-3 kinase, as blockade of this enzyme abolished the survival-promoting effect of high extracellular potassium concentrations. Our data indicate that increased network activity can prevent apoptosis in developing cortical neurons.     

Intracellular mediators of programmed cell death initiated at the cell surface receptor Fas

Abstract Apoptosis is a programmed cell death process, which plays a pivotal role in development, in tissue homeostasis and in several human diseases. Fas (CD95/Apo‐1) is a member of the “death receptors” family, a group of cell surface proteins that trigger apoptosis upon binding with their natural ligands. In the immune system, intracellular signal transduction triggered from Fas splits into two different pathways. The proteolytic pathway is mediated by a family of cysteine proteases, the caspases, responsible for the morphological changes occurring in the apoptotic process. To complete this death program, another series of events, involving a lipid pathway, is necessary. Upon Fas stimulation, a sequential activation of specific enzymes results in the accumulation of ceramides and GD3 ganglioside. GD3 directly induces mitochondrial damage and triggers the release of apoptogenic factors, allowing efficient execution of Fas‐mediated apoptosis.     

Harnessing programmed cell death as a therapeutic strategy in rheumatic diseases

Programmed cell death (PCD) is a key process in the regulation of immune cell development and peripheral immune homeostasis. Caspase-dependent apoptosis, as well as a number of alternative cell death mechanisms, account for immune cell PCD induced by cell-intrinsic and extrinsic pathways. In animal models, compelling evidence has emerged that genetic defects in PCD can result in autoimmune disease. Autoimmune disease can arise from single-gene mutations that affect PCD, and defective PCD has been observed in some tissues and cells from patients with rheumatic disease. Selectively inducing PCD in autoreactive B and T cells is very attractive as a therapeutic strategy because it offers the possibility of permanent elimination of these pathogenic cell subsets. In addition, the anti-inflammatory effects of apoptotic cells may add to the therapeutic benefit of induced PCD. Immune cell subsets vary widely in their sensitivity to specific inducers of cell death, and understanding these differences is key to predicting the outcome of inducing apoptosis for therapeutic means. Here, we review approaches that have been used to induce PCD in the treatment of autoimmune disease, and describe the prospects of bringing these experimental strategies into clinical practice.     

Uncoupling proteins prevent glucose-induced neuronal oxidative stress and programmed cell death

The central role of mitochondria in most pathways leading to programmed cell death (PCD) has focused our investigations into the mechanisms of glucose-induced neuronal degeneration. It has been postulated that hyperglycemic neuronal injury results from mitochondria membrane hyperpolarization and reactive oxygen species formation. The present study not only provides further evidence to support our model of glucose-induced PCD but also demonstrates a potent ability for uncoupling proteins (UCPs) to prevent this process. Dorsal root ganglion (DRG) neurons were screened for UCP expression by Western blotting and immunocytochemistry. The abilities of individual UCPs to prevent hyperglycemic PCD were assessed by adenovirus-mediated overexpression of UCP1 and UCP3. Interestingly, UCP3 is expressed not only in muscle, but also in DRG neurons under control conditions. UCP3 expression is rapidly downregulated by hyperglycemia in diabetic rats and by high glucose in cultured neurons. Overexpression of UCPs prevents glucose-induced transient mitochondrial membrane hyperpolarization, reactive oxygen species formation, and induction of PCD. The loss of UCP3 in DRG neurons may represent a significant contributing factor in glucose-induced injury. Furthermore, the ability to prevent UCP3 downregulation or to reproduce the uncoupling response in DRG neurons constitutes promising novel approaches to avert diabetic complications such as neuropathy.     

脊髓损伤后神经细胞程序性死亡方式的研究进展

正脊髓损伤(spinalcordinjury,SCI)是脊柱外伤中严重的并发症,可导致损伤节段以下严重的功能障碍,是青壮年致残的主要原因之一~([1])。由于其致伤机制复杂,临床尚无有效干预手段。近年来的研究表明,神经细胞的死亡是SCI复杂的病理进程中的核心环节~([2])。其中,各种程序性细胞死亡(programmed cell death,PCD)方式因其有可调控性而成为神经保护领域的研究热点~([3])。笔者对SCI后神经     

Proliferation-dependent vs. independent programmed cell death of prostatic cancer cells involves distinct gene regulation

Androgen-independent Dunning R-3327 AT-3 rat prostatic cancer cells can be induced to undergo programmed cell death in either a proliferation-dependent or independent manner depending upon the therapeutic agent used. In the present study, 5-fluorodeoxyuridine (5-FrdU) was used to induce proliferation-dependent death of the AT-3 cells via its ability to inhibit thymidylate synthetase. Ionomycin and thapsigargin were used to induce proliferation-independent death of these cells via their ability to sustain an elevation in intracellular free Ca²⁺. Based upon the temporal sequence of DNA fragmentation, morphologic changes, and loss of cell viability, each of the three test agents, at the doses used, induces the programmed death of AT-3 cells with essentially identical kinetics. Based upon these similarities, comparisons of the pattern of gene expression during the proliferation-dependent (i.e., 5-FrdU-induced) vs. proliferation-independent (i.e., ionomycin and thapsigargin-induced) programmed death of AT-3 cells allow identification of genes whose enhanced expression is involved in the initiation vs. completion of programmed cell death. Based upon this approach, enhanced H-ras and TRPM-2 expression is associated with initiation of proliferation-dependent programmed death of AT-3 cells while enhanced c-myc, calmdulin, and α-prothymosin expression is associated with initiation of proliferation-independent programmed death of these cells. In contrast, enhanced expression of glucose-regulated 78 kilodalton and tissue transglutaminase genes are associated with the completion of programmed cell death, since their expression is enhanced in both proliferation-dependent and independent programmed cell death of AT-3 cells. © 1994 Wiley-Liss, Inc.     

Mitochondrial participation in ischemic and traumatic neural cell death

Mitochondria play critical roles in cerebral energy metabolism and in the regulation of cellular Ca2+ homeostasis. They are also the primary intracellular source of reactive oxygen species, due to the tremendous number of oxidation-reduction reactions and the massive utilization of O2 that occur there. Metabolic trafficking among cells is also highly dependent upon normal, well-controlled mitochondrial activities. Alterations of any of these functions can cause cell death directly or precipitate death indirectly by compromising the ability of cells to withstand stressful stimuli. Abnormal accumulation of Ca2+ by mitochondria in response to exposure of neurons to excitotoxic levels of excitatory neurotransmitters, for example, glutamate, is a primary mediator of mitochondrial dysfunction and delayed cell death. Excitoxicity, along with inflammatory reactions, mechanical stress, and altered trophic signal transduction, all likely contribute to mitochondrial damage observed during the evolution of traumatic brain injury. The release of apoptogenic proteins from mitochondria into the cytosol serves as a primary mechanism responsible for inducing apoptosis, a form of cell death that contributes significantly to neurologic impairment following neurotrauma. Although several signals for the release of mitochondrial cell death proteins have been identified, the mechanisms by which these signals increase the permeability of the mitochondrial outer membrane to apoptogenic proteins is controversial. Elucidation of the precise biochemical mechanisms responsible for mitochondrial dysfunction during neurotrauma and the roles that mitochondria play in both necrotic and apoptotic cell death should provide new molecular targets for neuroprotective interventions.     

Acute ischemic stroke

Opinion statement Patients with acute ischemic stroke should be immediately transported to the nearest hospital for rapid evaluation and treatment. Intravenous t-PA within 3 hours of symptom onset is the recommended treatment for patients who meet the National Institute of Neurological Disorders and Stroke (NINDS) study eligibility criteria. Patients should be informed of the risk of symptomatic cerebral hemorrhage, and strict adherence to the NINDS study protocol is strongly recommended to optimize the risk-benefit ratio. Ischemic stroke patients who are not eligible for t-PA therapy should usually be started on aspirin. Intravenous heparin is not recommended as a standard treatment but may be considered for specific patient subgroups. Low-dose subcutaneous heparin is recommended for prophylaxis of deep vein thrombosis in immobilized patients. Management of stroke patients by a designated stroke team is recommended to facilitate prompt diagnosis and treatment and early initiation of rehabilitation therapy. We also recommend that physicians who manage patients with acute stroke maintain contact with local or regional stroke centers to facilitate referral of appropriate patients for intensive care or specialized diagnostic tests or therapies.     

程序性细胞死亡在肝脏缺血-再灌注损伤中的作用研究进展

肝移植是治疗终末期肝病的有效手段,但在肝移植过程中不可避免会发生肝脏缺血-再灌注损伤（HIRI）,可能导致早期移植物功能障碍或加剧排斥反应,其损伤防护机制有待深入研究。程序性细胞死亡是HIRI的重要发生机制,多种新型程序性细胞死亡形式参与了HIRI的病理过程,深入研究程序性细胞死亡有望进一步提高肝移植的治疗效果。本文就细胞凋亡、自噬及自噬依赖性死亡、铁死亡、坏死性凋亡、细胞焦亡、多聚二磷酸腺苷核糖聚合酶（PARP）-1依赖性细胞死亡等常见的程序性细胞死亡方式在HIRI中的研究进展予以综述,以期为提高肝移植手术成功率、改善受者预后提供参考。