Apoptosis genes and autoimmunity

Caspase-3 Levels Alter With Non-surgical Periodontal Therapy in Patients With Periodontitis

Background This study aims to evaluate the levels of caspase-3 in the gingival crevicular fluid (GCF) of chronic periodontitis patients before and after phase I treatment and compare it with those of healthy controls. Methodology The study involved 40 participants who were divided into two groups. Group 1 consisted of 30 chronic periodontitis patients, and group 2 consisted of 10 healthy controls. GCF was collected at baseline for both groups and at three months for group 1. Periodontal parameters and caspase-3 levels were analyzed before and after non-surgical therapy. Results Caspase-3 levels were higher in patients with chronic periodontitis compared with healthy controls. However, comparing baseline and postoperative levels, there was a statistically significant reduction in periodontal parameters and caspase-3 levels, with 0.80 ± 0.03 at baseline and 0.44 ± 0.02 at three months after non-surgical periodontal therapy. Conclusions Caspase-3, being the key molecule in apoptosis, was found to be at lower concentrations in healthy gingiva and was increased in the presence of periodontal disease. However, with non-surgical periodontal therapy, caspase-3 levels decreased, proving that non-surgical periodontal therapy affects host immune mechanisms and reduces apoptosis, thereby preventing disease progression.

Release of Antibodies and Cytokines from B Cells

Autoreactive B cells play a critical role in rheumatoid arthritis (RA). These cells differentiate into long-living memory B cells and autoantibody-producing plasma cells, and also present autoantigens to T cells to amplify misdirected immune responses. The therapeutic benefit of B-cell-deleting depleting therapies suggests that B cells are emerging as important factors in the pathogenesis of RA. Aiming at evaluation of the function of B cells, which are usually derived from peripheral blood of RA patients and healthy donors, it is possible to conduct a series of experiments, such as in vitro assessment of antibody production and BCR-mediated cytokine release. These techniques can also be applied for in vivo application.

Advances in the Pathogenesis and Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a genetically predisposed, female-predominant disease, characterized by multiple organ damage, that in its most severe forms can be life-threatening. The pathogenesis of SLE is complex and involves cells of both innate and adaptive immunity. The distinguishing feature of SLE is the production of autoantibodies, with the formation of immune complexes that precipitate at the vascular level, causing organ damage. Although progress in understanding the pathogenesis of SLE has been slower than in other rheumatic diseases, new knowledge has recently led to the development of effective targeted therapies, that hold out hope for personalized therapy. However, the new drugs available to date are still an adjunct to conventional therapy, which is known to be toxic in the short and long term. The purpose of this review is to summarize recent advances in understanding the pathogenesis of the disease and discuss the results obtained from the use of new targeted drugs, with a look at future therapies that may be used in the absence of the current standard of care or may even cure this serious systemic autoimmune disease.

Immaturin-Nuclease as a Model System for a Gene-Programmed Sexual Development and Rejuvenescence in Paramecium Life History

Fertilization-initiated development and adult-onset aging are standard features in the life history of eukaryotes. In Paramecium, the number of cell divisions after the birth of a new generation is an essential parameter of sexual phase transition and aging. However, the gene driving this process and its evolutionary origin have not yet been elucidated. Here we report several critical outcomes obtained by molecular genetics, immunofluorescence microscopy, transformation by microinjection, and enzymological analysis. The cloned immaturin gene induces sexual rejuvenation in both mature and senescent cells by microinjection. The immaturin gene originated from proteobacteria's glutathione-S-transferase (GST) gene. However, immaturin has been shown to lose GST activity and instead acquire nuclease activity. In vitro substrates for immaturin-nuclease are single- and double-stranded DNA, linear and circular DNA, and single-stranded viral genome RNA such as coronavirus. Anti-immaturin antibodies have shown that the subcellular localizations of immaturin are the macronucleus, cytoplasm, cell surface area, and cilia. The phase transition of sexuality is related to a decrease in the intracellular abundance of immaturin. We propose that sexual maturation and rejuvenation is a process programmed by the immaturin gene, and the sexual function of each age is defined by both the abundance and the intracellular localization mode of the immaturin-nuclease.

Autoantibodies in systemic lupus erythematosus: From immunopathology to therapeutic target

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ inflammatory damage and wide spectrum of autoantibodies. The autoantibodies, especially anti-dsDNA and anti-Sm autoantibodies are highly specific to SLE, and participate in the immune complex formation and inflammatory damage on multiple end-organs such as kidney, skin, and central nervous system (CNS). However, the underlying mechanisms of autoantibody-induced tissue damage and systemic inflammation are still not fully understood. Single cell analysis of autoreactive B cells and monoclonal antibody screening from patients with active SLE has improved our understanding on the origin of autoreactive B cells and the antigen targets of the pathogenic autoantibodies. B cell depletion therapies have been widely studied in the clinics, but the development of more specific therapies against the pathogenic B cell subset and autoantibodies with improved efficacy and safety still remain a big challenge. A more comprehensive autoantibody profiling combined with functional characterization of autoantibodies in diseases development will shed new insights on the etiology and pathogenesis of SLE and guide a specific treatment to individual SLE patients.

Mitochondria, Oxidative Stress, cAMP Signalling and Apoptosis: A Crossroads in Lymphocytes of Multiple Sclerosis, a Possible Role of Nutraceutics

Multiple sclerosis (MS) is a complex inflammatory and neurodegenerative chronic disease that involves the immune and central nervous systems (CNS). The pathogenesis involves the loss of blood–brain barrier integrity, resulting in the invasion of lymphocytes into the CNS with consequent tissue damage. The MS etiology is probably a combination of immunological, genetic, and environmental factors. It has been proposed that T lymphocytes have a main role in the onset and propagation of MS, leading to the inflammation of white matter and myelin sheath destruction. Cyclic AMP (cAMP), mitochondrial dysfunction, and oxidative stress exert a role in the alteration of T lymphocytes homeostasis and are involved in the apoptosis resistance of immune cells with the consequent development of autoimmune diseases. The defective apoptosis of autoreactive lymphocytes in patients with MS, allows these cells to perpetuate, within the CNS, a continuous cycle of inflammation. In this review, we discuss the involvement in MS of cAMP pathway, mitochondria, reactive oxygen species (ROS), apoptosis, and their interaction in the alteration of T lymphocytes homeostasis. In addition, we discuss a series of nutraceutical compounds that could influence these aspects.

Effects of TNF-α-308G/A Polymorphism on the Risk of Diabetic Nephropathy and Diabetic Retinopathy: An Updated Meta-Analysis

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are the major factors of morbidity and mortality in the patients with diabetes mellitus (DM). Growing studies have investigated the relationship between the TNF-α-308G/A polymorphism and the susceptibility to DN and DR, without achieving consensus. Thus, we conducted this meta-analysis to reach more comprehensive conclusions for these issues. Eligible studies were retrieved through electronic databases such as PubMed, Embase, Web of Science and China National Knowledge Infrastructure. Summary of odds ratios (OR) and 95% confidence intervals (CIs) were generated to evaluate the intensity of the associations. Statistical analyses were performed by STATA 11.0 and RevMan 5.2. There are fourteen eligible publications involving nineteen studies in this meta-analysis. TNF-α-308G/A polymorphism was significantly related to increasing risk of DN under recessive model (OR=1.37, 95% CI=1.03-1.83) and homozygous model (OR=1.54, 95% CI=1.15-2.06). Moreover, the similar results were also obtained in Asian groups for DN (recessive: OR=1.69, 95% CI=1.18-2.42; homozygous: OR=1.99, 95% CI=1.38-2.86; respectively), and significant association was also detected between TNF-α-308G/A and DN susceptibility in type 2 DM in recessive model (OR=1.39, 95% CI=1.02-1.89). No significant association was observed between TNF-α-308G/A and DR susceptibility in total analyses and subgroup analyses by ethnicity and type of DM. TNF-α-308G/A polymorphism may enhance the susceptibility to diabetic nephropathy, especially in Asian population and in T2DM patients, but not diabetic retinopathy.

Impact of quercetin supplementation on testicular functions in summer heat-stressed rabbits

<p>The current study was designed to determine the effects of dietary quercetin on epididymal sperm and testicular changes in male rabbits during summer heat stress (HS). Twelve adult male New Zealand white rabbits were submitted to summer heat conditions (temperature-humidity index 29.9±1.2). One group was fed a basal ration (BR; n = 6), whereas the other group was fed the same basal diet supplemented with quercetin (30 mg/kg d; Que-BR; n = 6) for 60 d, and both groups were sacrificed at the end of the experiment. Epididymis and testicles isolation was done for sperm, histopathology and apoptosis assessments. The results showed that quercetin improved epididymis weight, but did not affect other testicular dimensions except testicular length. A significant improvement was observed in epididymal sperm motility, concentration, kinematic parameters, viability, mitochondrial potential and acrosome integrity in Que-BR compared to the BR group. Lowered serum malondialdehyde level was observed in quercetin supplemented rabbits. Moreover, the quercetin supplementation maintained the interstitial stroma, seminiferous tubules architecture, germinal and Sertoli cells under HS, decreasing the apoptotic germ cell rate in seminiferous tubules. In conclusion, HS condition affects the sperm and testes configurations in rabbits and dietary quercetin minimises oxidative stress, which in turn protects the testes and sperm against HS induced damage.</p>

Testicular protective and antioxidant effects of selenium nanoparticles on Monosodium glutamate-induced testicular structure alterations in male mice

Background

Selenium has a protective antioxidant effect on several tissues. Monosodium glutamate (MSG), MSG has been known as flavor enhancer that influences reversely on male reproductive systems and having a number of side effects, including reproductive toxicity.

Objectives

The current study aims to evaluate the possible ameliorative functions of selenium nanoparticles (SeNPs) on MSG-induced reproductive toxicity.

Materials and methods

In total, 42 male mice included in this study were divided into six groups: control, MSG (LD), MSG (HD), SeNPs, MSG (LD) plus SeNPs and finally MSG (HD) plus SeNPs. Testosterone hormone, tumor necrosis factor-alpha (TNF-α), as well as the antioxidant biomarkers: superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase [CAT] and marker of lipid peroxidation [MDA], were examined. Histological and comet assay variations in the testicular tissues as markers of testicular damage after the MSG administration in two doses (MSG-LD and MSG-HD) either alone or combined with SeNPs.MSG in two doses (LD and HD) genotoxic effects were also evaluated and the ameliorative role of SeNPs on the testicular tissues were recorded.

Results

Results proved that the administration of SeNPs diminished the effect of MSG (LD and HD)-that induced decrease in testosterone hormone levels and elevated oxidative stress markers markedly. SeNPs had a potent antioxidant effect and elevated the antioxidant enzymes significantly and decreased lipid peroxidation markers as compared with MSG either (LD and HD) groups.

Conclusion

It is clear from the data that SeNPs inhibit testicular injury and improve the antioxidant state in male mice.

Testicular protective effects of ellagic acid on monosodium glutamate-induced testicular structural alterations in male rats

Ellagic acid (EA) has significant protective and antioxidant effects on several tissues. Monosodium glutamate (MG) is known as a flavor promoter that reversibly influences the male reproductive system. This study aims to assess the ameliorative effect of EA on oxidative stress and testicular damage induced by MG. In total, 48 male rats were included in this study and separated into six groups: control, EA (20 mg/kg), MG (low dose) (17.5 mg/kg), MG (high dose) (60 mg/kg), MG (low dose) combined with EA, and MG (high dose) combined with EA. Testicular antioxidant biomarkers [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRx), catalase (CAT), myeloperoxidase (MPO), and xanthine oxidase (XO)] were examined. Testes were examined and scored for histological variation as an indicator of testicular damage following administration of MG alone or in combination with EA. Serum testosterone, inhibin B, 8-hydroxydeoxyguanosine (as a marker of DNA damage), and transmission electron microscope sections of the testis were evaluated, and a comet assay was performed. Results showed that administration of EA combined with MG significantly elevated the levels of enzymatic antioxidants and decreased lipid peroxidation compared with MG treatment alone. EA elevated testosterone hormone levels and thus enhanced male reproductive capacity. It is clear from the data that EA inhibits histological and ultrastructure testicular damage and improves the redox state in male rats.

Acute toxic effect of lipopolysaccharides to blood tissue in rats and responses to vitamin E and sodium selenite

This work has been prepared to find out changes in the biochemicals with DNA damage, micronucleus, and apoptosis to lipopolysaccharides (LPS) alone or vitamin E (VE) and sodium selenite (SS) in rats' blood tissue. Rats were divided into eight groups according to the treatment into control vitamin E (VE) treatment group (200 mg/kg bw), sodium selenite (SS) treatment (0.35 mg/kg bw) group, VE + SS treatment group (200 + 0.35 mg/kg bw), LPS treatment group (10 mg/kg bw), LPS + VE (10 + 200 mg/kg bw), LPS + SS treatment (10 + 0.35 mg/kg bw), and LPS + SS+VE treatment (10 + 0.35 + 200 mg/kg bw) group for 6 hr. LPS increased malondialdehyde (MDA) level and decreased antioxidant enzymes' activities in rat erythrocytes and leukocytes. DNA damage of leukocytes with comet assay and RAPD-PCR was detected in LPS treatment group. The levels of micronucleus and apoptosis percentage were increased significantly at the end of 6 hr. VE and/or SS protected the LPS-induced erythrocytes and leukocytes against damage as they have caused amelioration of rats by altering the results. As a result, the co-administration of VE and/or SS against LPS-induced damage provides protection. VE and/or SS in patients and animal models with sepsis must be taken in the diet because they are protective against the cellular degradation caused by oxidative damage. PRACTICAL APPLICATIONS: LPS obtained from E. coli is used more frequently in experimental sepsis studies. When LPS is administered to experimental animals, interstitial pneumonia, adult respiratory fatal syndrome, acute tubular necrosis, and fatal effects such as coagulopathy and hypoglycemia may be seen in these animals. The co-treatment of VE and SS may be more effective than using them alone against LPS.

Extracellular DNA and autoimmune diseases

Extracellular DNA is secreted from various sources including apoptotic cells, NETotic neutrophils and bacterial biofilms. Extracellular DNA can stimulate innate immune responses to induce type-I IFN production after being endocytosed. This process is central in antiviral responses but it also plays important role in the pathogenesis of a range of autoimmune diseases such as systemic lupus erythematosus. We discuss the recent advances in the understanding of the role of extracellular DNA, released from apoptotic and NETotic cells, in autoimmunity.

Gold Nanoparticle-Induced Cell Death and Potential Applications in Nanomedicine

Cell death is crucial to human health and is related to various serious diseases. Therefore, generation of new cell death regulators is urgently needed for disease treatment. Nanoparticles (NPs) are now routinely used in a variety of fields, including consumer products and medicine. Exhibiting stability and ease of decoration, gold nanoparticles (GNPs) could be used in diagnosis and disease treatment. Upon entering the human body, GNPs contact human cells in the blood, targeting organs and the immune system. This property results in the disturbance of cell function and even cell death. Therefore, GNPs may act as powerful cell death regulators. However, at present, we are far from establishing a structure–activity relationship between the physicochemical properties of GNPs and cell death, and predicting GNP-induced cell death. In this review, GNPs’ size, shape, and surface properties are observed to play key roles in regulating various cell death modalities and related signaling pathways. These results could guide the design of GNPs for nanomedicine.

Release of Antibodies and Cytokines from B Cells

Autoreactive B cells play a critical role in rheumatoid arthritis. These cells differentiate into long-living memory B cells and autoantibody-producing plasma cells and also present autoantigens to T cells to amplify misdirected immune responses. The therapeutic benefit of B-cell-deleting therapies suggests that B cells are emerging as important factors in the pathogenesis of RA. Aiming at evaluation of the function of B cells, which are usually derived from peripheral blood of RA patients and healthy donors, it is possible to conduct a series of experiments, such as in vitro assessment of antibody production and BCR-mediated cytokine release. These techniques can also be applied for in vivo application.

PKK deficiency in B cells prevents lupus development in Sle lupus mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies that can result in damage to multiple organs. It is well documented that B cells play a critical role in the development of the disease. We previously showed that protein kinase C associated kinase (PKK) is required for B1 cell development as well as for the survival of recirculating mature B cells and B-lymphoma cells. Here, we investigated the role of PKK in lupus development in a lupus mouse model. We demonstrate that the conditional deletion of PKK in B cells prevents lupus development in Sle1Sle3 mice. The loss of PKK in Sle mice resulted in the amelioration of multiple classical lupus-associated phenotypes and histologic features of lupus nephritis, including marked reduction in the levels of serum autoantibodies, proteinuria, spleen size, peritoneal B-1 cell population and the number of activated CD4 T cells. In addition, the abundance of autoreactive plasma cells normally seen in Sle lupus mice was also significantly decreased in the PKK-deficient Sle mice. Sle B cells deficient in PKK display defective proliferation responses to BCR and LPS stimulation. Consistently, B cell receptor-mediated NF-κB activation, which is required for the survival of activated B cells, was impaired in the PKK-deficient B cells. Taken together, our work uncovers a critical role of PKK in lupus development and suggests that targeting the PKK-mediated pathway may represent a promising therapeutic strategy for lupus treatment.

TNF-alpha -308G/A and -238G/A polymorphisms and its protein network associated with type 2 diabetes mellitus

Several reports document the role of tumor necrosis factor alpha (TNF-α) and lipid metabolism in the context of acute inflammation as a causative factor in obesity-associated insulin resistance and as one of the causative parameter of type 2 diabetes mellitus (T2DM). Our aim was to investigate the association between -308G/A and -238G/A polymorphisms located in the promoter region of the TNF-α gene in T2DM in the Indian population with bioinformatics analysis of TNF-α protein networking with an aim to find new target sites for the treatment of T2DM. Demographics of 100 diabetes patients and 100 healthy volunteers were collected in a structured proforma and 3 ml blood samples were obtained from the study group, after approval of Institutional Ethics Committee of the hospital (IEC). The information on clinical parameters was obtained from medical records. Genomic DNA was extracted; PCR-RFLP was performed using TNF-α primers specific to detect the presence of SNPs. Various bioinformatics tools such as STRING software were used to determine its network with other associated genes. The PCR-RFLP studies showed that among the -238G/A types the GG genotype was 87%, GA genotype was 12% and AA genotype was 1%. Almost a similar pattern of results was obtained with TNF-α -308G/A polymorphism. The results obtained were evaluated statistically to determine the significance. By constructing TNF-α protein interaction network we could analyze ontology and hubness of the network to identify the networking of this gene which may influence the functioning of other genes in promoting T2DM. We could identify new targets in T2DM which may function in association with TNF-α. Through hub analysis of TNF-α protein network we have identified three novel proteins RIPK1, BIRC2 and BIRC3 which may contribute to TNF-mediated T2DM pathogenesis. In conclusion, our study indicated that some of the genotypes of TNF-α -308G/A, -238G/A were not significantly associated to type 2 diabetes mellitus, but TNF-α -308G/A polymorphism was reported to be a potent risk factor for diabetes in higher age (>45) groups. Also, the novel hub proteins may serve as new targets against TNF-α T2DM pathogenesis.

Vitamins in pancreatic cancer: a review of underlying mechanisms and future applications

Although there is increasing evidence that vitamins influence pancreatic adenocarcinoma biology and carcinogenesis, a comprehensive review is lacking. In this study, we performed a PubMed literature search to review the anticancer mechanisms and the preclinical and clinical studies that support the development of the bioactive vitamins A, C, D, E, and K in pancreatic cancer intervention. Preclinical studies have shown promising results for vitamin A in pancreatic cancer prevention, with clinical trials showing intriguing responses in combination with immunotherapy. For vitamin C, preclinical studies have shown slower tumor growth rates and/or increased survival when used alone or in combination with gemcitabine, with clinical trials with this combination revealing decreased primary tumor sizes and improved performance status. Preclinical studies with vitamin D analogues have shown potent antiproliferative effects and repression of migration and invasion of pancreatic cancer cells, with a clinical trial showing increased time to progression when calciferol was added to docetaxel. For vitamin E, preclinical studies have shown that δ-tocotrienol and γ-tocotrienol inhibited tumor cell growth and survival and augmented gemcitabine activity. Early-phase clinical trials with δ-tocotrienol are ongoing. Vitamin K demonstrates activation of apoptosis and inhibition of cellular growth in pancreatic tumor cells; however, there are no clinical studies available for further evaluation. Although preclinical and clinical studies are encouraging, randomized controlled trials with endpoints based on insights gained from mechanistic and preclinical studies and early-phase clinical trials are required to determine the efficacy of bioactive vitamin interventions in pancreatic cancer.

Latent Pathways Identification by Microarray Expression Profiles in Thyroid-Associated Ophthalmopathy Patients

This study aimed to screen potential genes related to thyroid-associated ophthalmopathy (TAO) and get a further understanding about the pathogenesis of this disease. GSE9340 was downloaded from Gene Expression Omnibus, including eight thyroid tissue samples from hyperthyroid patients without TAO and ten ones from hyperthyroid patients with TAO. The differentially expressed genes (DEGs) were identified by the linear models for microarray data package. And their potential functions were predicted by Gene Ontology (GO) and pathway enrichment analyses. Furthermore, protein-protein interaction (PPI) was obtained from the Search Tool for the Retrieval of Interacting Genes database, and the PPI network was visualized with Cytoscape. Then, module analysis was performed by the Molecular Complex Detection analysis. Additionally, the potential pathway interactions were identified by Latent Pathway Identification Analysis. Totally, 511 upregulated and 507 downregulated DEGs in TAO were screened. Some DEGs (e.g., UBE2C) were related to cell cycle, and DEGs encoding proteasome (e.g., PSMA1, PSMC5, PSMC4, and PSMD1) were related to negative regulation of ubiquitin-protein ligase activity. Several upregulated DEGs encoding signal recognition particle (e.g., SRP14, SRP54, and SRP9) were found to be enriched in protein export pathway. Furthermore, some pathways (e.g., ribosome and protein export) had interactions. The DEGs related to cell cycle (e.g., UBE2C), DEGs encoding proteasome (e.g., PSMA1, PSMC5, PSMC4, and PSMD1) and signal recognition particle (e.g., SRP14, SRP54, and SRP9), as well as pathways of ribosome, protein export and retinol metabolism, might play key roles in the development of TAO.

Ubr3 E3 ligase regulates apoptosis by controlling the activity of DIAP1 in Drosophila

Apoptosis has essential roles in a variety of cellular and developmental processes. Although the pathway is well studied, how the activities of individual components in the pathway are regulated is less understood. In Drosophila, a key component in apoptosis is Drosophila inhibitor of apoptosis protein 1 (DIAP1), which is required to prevent caspase activation. Here, we demonstrate that Drosophila CG42593 (ubr3), encoding the homolog of mammalian UBR3, has an essential role in regulating the apoptosis pathway. We show that loss of ubr3 activity causes caspase-dependent apoptosis in Drosophila eye and wing discs. Our genetic epistasis analyses show that the apoptosis induced by loss of ubr3 can be suppressed by loss of initiator caspase Drosophila Nedd2-like caspase (Dronc), or by ectopic expression of the apoptosis inhibitor p35, but cannot be rescued by overexpression of DIAP1. Importantly, we show that the activity of Ubr3 in the apoptosis pathway is not dependent on its Ring-domain, which is required for its E3 ligase activity. Furthermore, we find that through the UBR-box domain, Ubr3 physically interacts with the neo-epitope of DIAP1 that is exposed after caspase-mediated cleavage. This interaction promotes the recruitment and ubiquitination of substrate caspases by DIAP1. Together, our data indicate that Ubr3 interacts with DIAP1 and positively regulates DIAP1 activity, possibly by maintaining its active conformation in the apoptosis pathway.

Protective effects of melatonin against arsenic-induced apoptosis and oxidative stress in rat testes

This study aimed to investigate the protective effects of melatonin against arsenic-induced apoptosis and oxidative stress in rat testes. A total of 27 male rats were divided into 3 groups: control (saline: 5 ml kg−1 day−1, intragastrically), arsenic (sodium arsenite (NaAsO2): 5 mg kg−1 day−1, intragastrically), and arsenic + melatonin (sodium arsenite (NaAsO2): 5 mg kg−1 day−1, intragastrically and melatonin: 25 mg kg−1 day−1, intraperitoneally) group. At the end of 30 days, the rats were killed under anesthesia. Histopathological examination showed that testicular injury mediated by arsenic was ameliorated by the administration of melatonin. The number of apoptotic germ cell was increased, and the number of proliferating cell nuclear antigen (PCNA)-positive germ cell was decreased in testis after arsenic administration. Our data indicate a significant reduction in the activity of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and there was a rise in the expression of PCNA in testis of arsenic + melatonin group. The decreased superoxide dismutase, catalase, and glutathione peroxidase activities as well as increased malondialdehyde levels in testis due to arsenic administration were also counteracted by melatonin. These data suggested that melatonin has beneficial effects against arsenic-induced testicular damage by decreasing morphological damage, germ cell apoptosis, lipid peroxidation, and oxidative stress. Our results suggest that melatonin plays a protective role against arsenic-induced testicular apoptosis and oxidative stress.

Pharmacokinetics of Py-Im polyamides depend on architecture: cyclic versus linear

The pharmacokinetic properties of three pyrrole-imidazole (Py-Im) polyamides of similar size and Py-Im content but different shape were studied in the mouse. Remarkably, hairpin and cyclic oligomers programmed for the same DNA sequence 5'-WGGWWW-3' displayed distinct pharmacokinetic properties. Furthermore, the hairpin 1 and cycle 2 exhibited vastly different animal toxicities. These data provide a foundation for design of DNA binding Py-Im polyamides to be tested in vivo.

Engineering a photoactivated caspase-7 for rapid induction of apoptosis

Apoptosis is a cell death program involved in the development of multicellular organisms, immunity, and pathologies ranging from cancer to HIV/AIDS. We present an engineered protein that causes rapid apoptosis of targeted cells in monolayer culture after stimulation with blue light. Cells transfected with the protein switch L57V, a tandem fusion of the light-sensing LOV2 domain and the apoptosis-executing domain from caspase-7, rapidly undergo apoptosis within 60 min after light stimulation. Constant illumination of under 5 min or oscillating with 1 min exposure had no effect, suggesting that cells have natural tolerance to a short duration of caspase-7 activity. Furthermore, the overexpression of Bcl-2 prevented L57V-mediated apoptosis, suggesting that although caspase-7 activation is sufficient to start apoptosis, it requires mitochondrial contribution to fully commit.

Direct measurement of cathepsin B activity in the cytosol of apoptotic cells by an activity-based probe

Cells control their own death through a program termed apoptosis, which is indispensable for development and homeostasis in all metazoans. Lysosomal cysteine proteases are not normally thought of as participating in apoptosis; however, recent reports have shown that the cathepsin proteases can be released from the lysosome during apoptosis, where they can participate in cell death. We report here the development of an activity-based probe that, under optimized conditions, reports on cathepsin B activity only in apoptotic cells by reading out the release of cathepsin B from the lysosomes. Biochemical characterization of apoptosis in cells from cathepsin B null mice shows delayed and suboptimal activation of caspases. Our data further supports a role for cathepsin B in the cytosol as a positive regulator of a cell death feed-forward loop and provides a chemical tool for future investigations.

Fluorinated isatin derivatives. Part 3. New side-chain fluoro-functionalized pyrrolidinyl sulfonyl isatins as potent caspase-3 and -7 inhibitors

Background: Dysregulation of type I programmed cell death (apoptosis) leads to a variety of diseases, among which cancer, cardiovascular and neurodegenerative disorders are the most prominent and widespread. Effector caspases such as caspases-3 and -7 get activated during the apoptotic signaling cascade and hence represent a biological target for the diagnosis and therapy of apoptosis-associated diseases. Methods: Synthesis of potent fluorinated analogs of the lead compound (S)-(+)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin facilitates the aim-oriented identification of precursor candidates for 18F-radiofluorination resulting in radiolabeled compounds that could be employed as tracers for the specific imaging of apoptosis in vivo, using positron-emission tomography. Conclusion: Within a series of new mono-, di- and trifluoromethylated pyrrolidine ring analogs of the lead compound, high inhibition potencies were found for caspases-3 and -7 with IC50 values up to 30 and 37 nM, respectively. A new oxidative desulfurization–fluorination protocol was shown to be a versatile technique for fluorine incorporation.

Apoptotic cells promote their own clearance and immune tolerance through activation of the nuclear receptor LXR

Effective clearance of apoptotic cells by macrophages is essential for immune homeostasis. The transcriptional pathways that allow macrophages to sense and respond to apoptotic cells are poorly defined. We found that liver X receptor (LXR) signaling was important for both apoptotic cell clearance and the maintenance of immune tolerance. Apoptotic cell engulfment activated LXR and thereby induced the expression of Mer, a receptor tyrosine kinase critical for phagocytosis. LXR-deficient macrophages exhibited a selective defect in phagocytosis of apoptotic cells and an aberrant proinflammatory response to them. As a consequence of these defects, mice lacking LXRs manifested a breakdown in self-tolerance and developed autoantibodies and autoimmune glomerulonephritis. Treatment with an LXR agonist ameliorated disease progression in a mouse model of lupus-like autoimmunity. Thus, activation of LXR by apoptotic cells engages a virtuous cycle that promotes their own clearance and couples engulfment to the suppression of inflammatory pathways.

The Bcl-2 family antagonist ABT-737 significantly inhibits multiple animal models of autoimmunity

The Bcl-2 family of proteins plays a critical role in controlling immune responses by regulating the expansion and contraction of activated lymphocyte clones by apoptosis. ABT-737, which was originally developed for oncology, is a potent inhibitor of Bcl-2, Bcl-x(L), and Bcl-w protein function. There is evidence that Bcl-2-associated dysregulation of lymphocyte apoptosis may contribute to the pathogenesis of autoimmunity and lead to the development of autoimmune diseases. In this study, we report that ABT-737 treatment resulted in potent inhibition of lymphocyte proliferation as measured by in vitro mitogenic or ex vivo Ag-specific stimulation. More importantly, ABT-737 significantly reduced disease severity in tissue-specific and systemic animal models of autoimmunity. Bcl-2 family antagonism by ABT-737 was efficacious in treating animal models of arthritis and lupus. Our results suggest that treatment with a Bcl-2 family antagonist represents a novel and potentially attractive therapeutic approach for the clinical treatment of autoimmunity.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

Family-based analysis of tumor necrosis factor and lymphotoxin-alpha tag polymorphisms with type 1 diabetes in the population of South Croatia

Tumor necrosis factor (TNF) and lymphotoxin-alpha (LTA) are cytokines with a wide range of inflammatory and immunomodulatory activities. Type 1 diabetes is an autoimmune disease characterized by destruction of insulin-producing pancreatic beta cells. The aim of the present study was to evaluate the association of polymorphisms in the TNF/LTA gene region with susceptibility to type 1 diabetes. We investigated 11 TNF/LTA tag polymorphisms, designed to capture the majority of common variation in the region, in 160 trio families from South Croatia. We observed overtransmission of alleles from parents to affected child at five variants: (rs909253, allele C, p = 1.2x10(-4); rs1041981, allele A, p = 1.1x10(-4); rs1800629 (G-308A), allele A, p = 1.2x10(-4); rs361525 (G-238A), allele G, p = 8.2x10(-3) and rs3093668, allele G, p = 0.014). We also identified overtransmission of the rs1800629(G-308A)-rs361525(G-238A) A-G haplotype, p = 2.384x10(-5). The present study found an association of the TNF/LTA gene region with type 1 diabetes. A careful assessment of TNF/LTA variants adjusted for linkage disequilibrium with HLA loci is needed to further clarify the role of these genes in type 1 diabetes susceptibility in the population of South Croatia.

FLIP and the death effector domain family

Death effector domains (DEDs) are protein interaction modules found in a number of proteins known to regulate apoptosis from death receptors. The core DED family members that orchestrate programmed cell death from death receptors include the adaptor protein FADD, the initiator caspases procaspases-8 and -10 and the regulatory protein c-FLIP. Through homotypic DED interactions, these proteins assemble into the death-inducing signaling complex (DISC) to regulate initiator caspase activation and launch the apoptotic proteolytic cascade. A considerable body of evidence, however, is revealing that the same core group of DED-containing proteins also paradoxically promotes survival and proliferation in lymphocytes and possibly other cell types. This review delves into recent findings regarding these two opposing functional aspects of the core DED proteins. We discuss the current effort expanding our structural and biochemical view of how DED proteins assemble into the DISC to fully activate initiator caspases and execute cell death, and finally we examine details linking the same proteins to proliferation and describe how this outcome might be achieved through restricted activation of initiator caspases.

Detection of apoptotic cells in cerebrospinal fluid of patients suffering from neurological disease

Apoptotic elimination of pathogenic immune cells is considered one of several regulatory mechanisms in inflammatory diseases. To explore the potential relationship between detection of apoptotic cells in the cerebrospinal fluid (CSF) and different types of neurological diseases, we examined cellular apoptosis at the stage of DNA fragmentation, defined by morphological criteria and a molecular biology technique (in situ tailing). During a first phase, 3446 CSF samples derived from admitted patients suffering of inflammatory (IND) and non-inflammatory neurological diseases (NIND) were analysed in the course of routine clinical diagnostics. First, all specimens were inspected for cells displaying atypical morphology following established morphological criteria of intact lymphocytes or apoptosis. In a second phase, 76 additional CSF samples collected from individuals according to investigated clinical groups were analysed in parallel by means of in situ tailing, which indicates the advanced degree of apoptotic demise through labelling of controlled DNA fragmentation. No apoptotic processes were detected by either analytical method in CSF of clinically distinct diseases, amongst others multiple sclerosis (MS). This indicates that the detection of apoptotic cells in CSF during clinical routine diagnostics does not have sufficient explanatory power for the investigated conditions. Furthermore, based on immunohistochemistry, the proportion of CSF lymphocytes expressing the pro-apoptotic receptor Fas (CD95) tended to be higher in NIND patients compared to patients with other IND and MS, but the difference was not statistically significant. In contrast, expression of the anti-apoptotic protein Bcl-2 did not differ between investigated patient groups.

Interactions of DNR1 with the apoptotic machinery of Drosophila melanogaster

Caspases are crucial activators of apoptosis and NF-kappaB signaling in vertebrates and invertebrates. In Drosophila, the caspase-9 counterpart Dronc is essential for most apoptotic death, whereas the caspase-8 homolog Dredd activates NF-kappaB signaling in response to gram-negative bacterial infection. The mechanics of caspase regulation are conserved and include the activities of a family of inhibitor of apoptosis (IAP) proteins. The RING-domain-bearing protein Defense repressor 1 (Dnr1), blocks ectopic Dredd-mediated induction of an NF-kappaB reporter in the Drosophila S2 cell line. In this study, we present novel data indicating that Dnr1 impacts on Dronc-dependent regulation of the apoptotic program. We show that depletion of Dnr1 results in elevated Dronc protein levels, which translates to increased caspase activation and activity upon induction of apoptosis. Conversely, we demonstrate that overexpression of Dnr1 blocks apoptotic caspase activity and prevents induction of apoptosis in tissue culture assays. Furthermore, we show that Dnr1 overexpression significantly reduces Dronc protein levels and identify the domains of Dnr1 necessary for these effects. From these data, we propose that Dnr1 inhibits initiator caspases in S2 cells.

Calcium blocks formation of apoptosome by preventing nucleotide exchange in Apaf-1

Apaf-1 plays an essential role in apoptosis. In the presence of cytochrome c and dATP, Apaf-1 assembles into an oligomeric apoptosome, which is responsible for the activation of procaspase-9 and the maintenance of the enzymatic activity of the processed caspase-9. Regulation of apoptosome assembly by other cellular factors is poorly understood. Here we report that physiological concentrations of calcium ion negatively affect the assembly of apoptosome by inhibiting nucleotide exchange in the monomeric, autoinhibited Apaf-1 protein. Consequently, calcium blocks the ability of Apaf-1 to activate caspase-9. These observations suggest an important role of calcium homeostasis on the Apaf-1-dependent apoptotic pathway.

Type-I interferons and systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by the production of autoantibodies directed against nuclear antigens and chronic inflammation affecting multiple tissues. Complex genetic disorders are at the origin of the disease in humans and in SLE-prone mice, leading to the escape of auto-reactive B-lymphocytes from central and peripheral control checkpoints that operate normally in healthy organisms. Although necessary, autoimmune B-cells are not sufficient and additional mechanisms such as T-cell help are clearly needed for the disease to occur. The role of type-I interferons (type-I IFNs), and in particular IFNalpha, as prominent cofactors for SLE was suggested years ago. Leading observations in patients and recent data in SLE-prone mice have now established IFNalpha as a major actor in SLE. Several systemic clinical symptoms and laboratory findings can indeed be interpreted as downstream effects of a high IFNalpha production, and point to this cytokine as a link between the expansion of autoimmune B-cells and the stimulation of other components of the immune system. Consequently, a vicious circle is established with overt immune-cell activation and inflammatory infiltrates culminating in the selective destruction of tissue targets, notably the kidney. These notions can now be transplanted to the clinic and designate IFNalpha as a new promising therapeutic target.

The expression of pro- and anti-apoptotic Bcl-2 family proteins in peribronchiolar lymphocytes from patients with diffuse panbronchiolitis

Diffuse panbronchiolitis (DPB) is a distinctive form of small airway disease, which is characterized by chronic inflammation with lymphocyte infiltration around bronchioles. The aim of this study was to evaluate the importance of factors related to apoptosis in peribronchiolar lymphocytes of DPB. We employed immunohistochemical methods for the localization of Bax (a promoter of apoptosis), Bcl-2 (an inhibitor of apoptosis), and caspase-3 (a key executioner molecule of apoptosis) in lung tissues of five patients with DPB. In all patients, immunostaining for Bax was almost completely absent in accumulated lymphocytes around the bronchioles and in lymphocytes of the parafollicular area that correspond to a zone populated by T cells. In contrast to the reaction for Bax, Bcl-2 immunoreactivity was uniformly strong in all of the patients. The pattern of staining for caspase-3 was similar to that for Bax in all of the patients. In normal lung tissue, a few lymphocytes showed negative immunostaining for Bcl-2 and a positive reaction for caspase-3. Our results suggest that Bcl-2 protein may provide T-lymphocyte survival and hypercellularity in the bronchioles, thereby contributing to the progression of DPB.

Crystal Structure of a Viral FLIP

Death receptor signaling is initiated by the assembly of the death-inducing signaling complex, which culminates in the activation of the initiator caspase, either caspase-8 or caspase-10. A family of viral and cellular proteins, known as FLIP, plays an essential role in the regulation of death receptor signaling. Viral FLIP (v-FLIP) and short cellular FLIP (c-FLIPS) inhibit apoptosis by interfering with death receptor signaling. The structure and mechanisms of v-FLIP and c-FLIPS remain largely unknown. Here we report a high resolution crystal structure of MC159, a v-FLIP derived from the molluscum contagiosum virus, which is a member of the human poxvirus family. Unexpectedly, the two tandem death effector domains (DEDs) of MC159 rigidly associate with each other through a hydrophobic interface. Structure-based sequence analysis suggests that this interface is conserved in the tandem DEDs from other v-FLIP, c-FLIPS, and caspase-8 and -10. Strikingly, the overall packing arrangement between the two DEDs of MC159 resembles that between the caspase recruitment domains of Apaf-1 and caspase-9. In addition, each DED of MC159 contains a highly conserved binding motif on the surface, to which loss-of-function mutations in MC159 map. These observations, in conjunction with published evidence, reveal significant insights into the function of v-FLIP and suggest a mechanism by which v-FLIP and c-FLIPS inhibit death receptor signaling.

Mechanisms of apoptosis through structural biology

Apoptosis plays a central role in the development and homeostasis of metazoans. Research in the past two decades has led to the identification of hundreds of genes that govern the initiation, execution, and regulation of apoptosis. An earlier focus on the genetic and cell biological characterization has now been complemented by systematic biochemical and structural investigation, giving rise to an unprecedented level of clarity in many aspects of apoptosis. In this review, we focus on the molecular mechanisms of apoptosis by synthesizing available biochemical and structural information. We discuss the mechanisms of ligand binding to death receptors, actions of the Bcl-2 family of proteins, and caspase activation, inhibition, and removal of inhibition. Although an emphasis is given to the mammalian pathways, a comparative analysis is applied to related mechanistic information in Drosophila and Caenorhabditis elegans.

Is the association between TNF-alpha-308 A allele and DMT1 independent of HLA-DRB1, DQB1 alleles?

The aim of the study was to assess chosen factors of genetic susceptibility to DMT1: DRB1, DQB1, and TNF-alpha polymorphisms-308 (G/A) in children with DMT1 and their up-to-now healthy siblings. Then we tested whether the association between TNF-alpha genes and DMT1 is independent of HLA. 87 diabetic children, their 78 siblings, and 85 persons from healthy control group were followed up. The highest risk of DMT1 was connected with alleles: DRB1*0401 (OR = 3.39; CI: 1.55-7.41), DRB1*0301 (OR = 2.72; CI: 1.48-5.01), DQB1*0201 (OR = 4.04; CI: 2.17-7.52), DQB1*0302 (OR = 5.08; CI: 2.54-10.14), and TNF-alpha-308 A allele (OR = 2.59; CI: 1.23-5.44). Moreover linkage disequilibrium for TNF-alpha-308 A allele with DRB1*0301 and DQB1*0201 was observed in both diabetic children and their siblings. Diabetic children and their siblings present similar genetic risk factors for DMT1. The association between TNF-alpha-308 A allele and DMT1 is dependent of HLA-DRB1 and DQB1 alleles.

Programmed cell death of myelin basic protein-specific T lymphocytes is reduced in patients with acute multiple sclerosis

We investigated the apoptosis of myelin basic protein (MBP)-specific T lymphocytes in multiple sclerosis (MS) patients with acute (AMS) or stable (SMS) MS by evaluating the expression of apoptosis markers on peripheral cells. Cells of healthy controls (HC) were evaluated as well. Results showed that mitogen-stimulated apoptosis was comparable among patients and controls, whereas MBP-stimulated CD4+ and CD8+ 7-AAD+ and 7-AAD+ Fas+ cell (apoptotic cells) were significantly reduced in AMS patients. A reduction of the apoptotic rate of myelin-specific CD4+ and CD8+ T lymphocytes could be involved in the immune-mediated destruction of the myelin sheath seen in AMS patients.

MicroRNAs and the regulation of cell death

Programmed cell death, or apoptosis, is ubiquitous, both during development and in the adult. Many components of the evolutionarily conserved machinery that brings about and regulates cell death have been identified, and all of these are proteins. However, in the past three years it has become clear that roughly 1% of predicted genes in animals encode small noncoding RNAs known as microRNAs, which regulate gene function. Here we review the recent identification of microRNA cell death regulators in Drosophila, hints that such regulators are also likely to exist in mammals, and more generally the approaches and tools that are now available to probe roles for noncoding RNAs in the control of cell death.

The genetics of cell death: approaches, insights and opportunities in Drosophila

Cell death is ubiquitous in metazoans and involves the action of an evolutionarily conserved process known as programmed cell death or apoptosis. In Drosophila melanogaster, it is now uniquely possible to screen for genes that determine the fate - life or death - of any cell or population of cells during development and in the adult. This review describes these genetic approaches and the key insights into cell-death mechanisms that have been obtained, as well as the outstanding questions that these techniques can help to answer.