Role of PARP-1 and PARP-2 in the expression of apoptosis-regulating genes in HeLa cells

Poly (ADP-ribose) polymerase-1 (PARP-1) is a DNA-binding enzyme involved in DNA damage processing, apoptosis, and genetic stability. Many lines of evidence suggest that PARP-1 is implicated in transcriptional regulation of various genes through the modulation of chromatin structure or through direct interaction with transcription factors and/or transcription factor-binding sites. In the present study, we applied TaqMan Low-Density Array analyses to investigate the expression of genes involved in apoptotic cell death induced by an alkylating agent. Using RNA interference, we determined the roles of PARP-1 and PARP-2 in transcriptional regulation during apoptosis in HeLa cells. Of the 93 genes monitored, 33 differentially expressed genes were identified after induction of apoptosis. Whereas the down-regulation of PARP-1 and PARP-2 had no impact on gene expression per se, we observed that Bcl10, c-Rel, and tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and -2 are differentially expressed after induction of apoptosis in a PARP-1-dependent manner. These findings suggest that PARP-1—but not PARP-2—is required for proper expression of major genes involved in regulation of apoptosi

Uncoupling of DNA excision repair and nucleosomal unfolding in poly (ADP-ribose)-depleted mammalian cells

The repair of DNA damage in eukaryotic cells is closely coupled with local changes of chromatin structure such that newly synthesized repair patches transiently appear in ‘free' DNA domains with increased accessibility to enzymatic and chemical probes. We have isolated these domains from mammalian cells repairing bulky DNA adducts. During the first 3 h of repair, excision of adducts occurred exclusively in free DNA and was closely linked with the appearance of newly synthesized repair patches. Following depletion of chromatin-bound poly(ADP-ribose), the repositioning of repair patches into these domains was completely blocked, although overall repair patch synthesis was unaltered. Concomitantly, DNA adducts were no longer excised and tended to accumulate in free DNA domains. Our results suggest a tight coupling of the excision step with the formation of free DNA domains by a mechanism involving poly ADP-ribosylation of chromatin protein

Poly(ADP-ribose)glycohydrolase is an upstream regulator of Ca2+ fluxes in oxidative cell death

Oxidative DNA damage to cells activates poly(ADP-ribose)polymerase-1 (PARP-1) and the poly(ADP-ribose) formed is rapidly degraded to ADP-ribose by poly(ADP-ribose)glycohydrolase (PARG). Here we show that PARP-1 and PARG control extracellular Ca2+ fluxes through melastatin-like transient receptor potential 2 channels (TRPM2) in a cell death signaling pathway. TRPM2 activation accounts for essentially the entire Ca2+ influx into the cytosol, activating caspases and causing the translocation of apoptosis inducing factor (AIF) from the inner mitochondrial membrane to the nucleus followed by cell death. Abrogation of PARP-1 or PARG function disrupts these signals and reduces cell death. ADP-ribose-loading of cells induces Ca2+ fluxes in the absence of oxidative damage, suggesting that ADP-ribose is the key metabolite of the PARP-1/PARG system regulating TRPM2. We conclude that PARP-1/PARG control a cell death signal pathway that operates between five different cell compartments and communicates via three types of chemical messengers: a nucleotide, a cation, and protein

Bioenergy production and sustainable development: Science base for policymaking remains limited

The possibility of using bioenergy as a climate change mitigation measure has sparked a discussion of whether and how bioenergy production contributes to sustainable development. We undertook a systematic review of the scientific literature to illuminate this relationship and found a limited scientific basis for policymaking. Our results indicate that knowledge on the sustainable development impacts of bioenergy production is concentrated in a few well‐studied countries, focuses on environmental and economic impacts, and mostly relates to dedicated agricultural biomass plantations. The scope and methodological approaches in studies differ widely and only a small share of the studies sufficiently reports on context and/or baseline conditions, which makes it difficult to get a general understanding of the attribution of impacts. Nevertheless, we identified regional patterns of positive or negative impacts for all categories – environmental, economic, institutional, social and technological. In general, economic and technological impacts were more frequently reported as positive, while social and environmental impacts were more frequently reported as negative (with the exception of impacts on direct substitution of GHG emission from fossil fuel). More focused and transparent research is needed to validate these patterns and develop a strong science underpinning for establishing policies and governance agreements that prevent/mitigate negative and promote positive impacts from bioenergy production

Rapid regulation of telomere length is mediated by poly(ADP-ribose) polymerase-1

Shelterin/telosome is a multi-protein complex at mammalian telomeres, anchored to the double-stranded region by the telomeric-repeat binding factors-1 and -2. In vitro modification of these proteins by poly(ADP-ribosyl)ation through poly(ADP-ribose) polymerases-5 (tankyrases) and -1/-2, respectively, impairs binding. Thereafter, at least telomeric-repeat binding factor-1 is degraded by the proteasome. We show that pharmacological inhibition of poly(ADP-ribose) polymerase activity in cells from two different species leads to rapid decrease in median telomere length and stabilization at a lower setting. Specific knockdown of poly(ADP-ribose) polymerase-1 by RNA interference had the same effect. The length of the single-stranded telomeric overhang as well as telomerase activity were not affected. Release of inhibition led to a fast re-gain in telomere length to control levels in cells expressing active telomerase. We conclude that poly(ADP-ribose) polymerase-1 activity and probably its interplay with telomeric-repeat binding factor-2 is an important determinant in telomere regulation. Our findings reinforce the link between poly(ADP-ribosyl)ation and aging/longevity and also impact on the use of poly(ADP-ribose) polymerase inhibitors in tumor therapy

Poly(ADP-ribose)glycohydrolase is an upstream regulator of Ca2+ fluxes in oxidative cell death

Oxidative DNA damage to cells activates poly(ADP-ribose)polymerase-1 (PARP-1) and the poly(ADP-ribose) formed is rapidly degraded to ADP-ribose by poly(ADP-ribose)glycohydrolase (PARG). Here we show that PARP-1 and PARG control extracellular Ca2+ fluxes through melastatin-like transient receptor potential 2 channels (TRPM2) in a cell death signaling pathway. TRPM2 activation accounts for essentially the entire Ca2+ influx into the cytosol, activating caspases and causing the translocation of apoptosis inducing factor (AIF) from the inner mitochondrial membrane to the nucleus followed by cell death. Abrogation of PARP-1 or PARG function disrupts these signals and reduces cell death. ADP-ribose-loading of cells induces Ca2+ fluxes in the absence of oxidative damage, suggesting that ADP-ribose is the key metabolite of the PARP-1/PARG system regulating TRPM2. We conclude that PARP-1/PARG control a cell death signal pathway that operates between five different cell compartments and communicates via three types of chemical messengers: a nucleotide, a cation, and proteins

Voting for Direct Democracy: Evidence from a Unique Popular Initiative in Bavaria

We analyze a constitutional change in the German State of Bavaria where citizens, not politicians, granted themselves more say in politics at the local level through a constitutional initiative at the state level. This institutional setting allows us to focus on revealed preferences for direct democracy and to identify factors which explain this preference. Empirical results suggests support for direct democracy is rather related to dissatisfaction with representative democracy in general than with an elected governing party

Management of Cerebral Venous Thrombosis Due to Adenoviral COVID-19 Vaccination

Objective Cerebral venous thrombosis (CVT) caused by vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare adverse effect of adenovirus-based severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) vaccines. In March 2021, after autoimmune pathogenesis of VITT was discovered, treatment recommendations were developed. These comprised immunomodulation, non-heparin anticoagulants, and avoidance of platelet transfusion. The aim of this study was to evaluate adherence to these recommendations and its association with mortality. Methods We used data from an international prospective registry of patients with CVT after the adenovirus-based SARS-CoV-2 vaccination. We analyzed possible, probable, or definite VITT-CVT cases included until January 18, 2022. Immunomodulation entailed administration of intravenous immunoglobulins and/or plasmapheresis. Results Ninety-nine patients with VITT-CVT from 71 hospitals in 17 countries were analyzed. Five of 38 (13%), 11 of 24 (46%), and 28 of 37 (76%) of the patients diagnosed in March, April, and from May onward, respectively, were treated in-line with VITT recommendations (p < 0.001). Overall, treatment according to recommendations had no statistically significant influence on mortality (14/44 [32%] vs 29/55 [52%], adjusted odds ratio [OR] = 0.43, 95% confidence interval [CI] = 0.16-1.19). However, patients who received immunomodulation had lower mortality (19/65 [29%] vs 24/34 [70%], adjusted OR = 0.19, 95% CI = 0.06-0.58). Treatment with non-heparin anticoagulants instead of heparins was not associated with lower mortality (17/51 [33%] vs 13/35 [37%], adjusted OR = 0.70, 95% CI = 0.24-2.04). Mortality was also not significantly influenced by platelet transfusion (17/27 [63%] vs 26/72 [36%], adjusted OR = 2.19, 95% CI = 0.74-6.54). Conclusions In patients with VITT-CVT, adherence to VITT treatment recommendations improved over time. Immunomodulation seems crucial for reducing mortality of VITT-CVT. ANN NEUROL 2022Peer reviewe

Sex differences in cerebral venous sinus thrombosis after adenoviral vaccination against COVID-19

Introduction: Cerebral venous sinus thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is a severe disease with high mortality. There are few data on sex differences in CVST-VITT. The aim of our study was to investigate the differences in presentation, treatment, clinical course, complications, and outcome of CVST-VITT between women and men. Patients and methods: We used data from an ongoing international registry on CVST-VITT. VITT was diagnosed according to the Pavord criteria. We compared the characteristics of CVST-VITT in women and men. Results: Of 133 patients with possible, probable, or definite CVST-VITT, 102 (77%) were women. Women were slightly younger [median age 42 (IQR 28–54) vs 45 (28–56)], presented more often with coma (26% vs 10%) and had a lower platelet count at presentation [median (IQR) 50x109/L (28–79) vs 68 (30–125)] than men. The nadir platelet count was lower in women [median (IQR) 34 (19–62) vs 53 (20–92)]. More women received endovascular treatment than men (15% vs 6%). Rates of treatment with intravenous immunoglobulins were similar (63% vs 66%), as were new venous thromboembolic events (14% vs 14%) and major bleeding complications (30% vs 20%). Rates of good functional outcome (modified Rankin Scale 0-2, 42% vs 45%) and in-hospital death (39% vs 41%) did not differ. Discussion and conclusions: Three quarters of CVST-VITT patients in this study were women. Women were more severely affected at presentation, but clinical course and outcome did not differ between women and men. VITT-specific treatments were overall similar, but more women received endovascular treatment.</p

Sex differences in cerebral venous sinus thrombosis after adenoviral vaccination against COVID-19

Introduction: Cerebral venous sinus thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is a severe disease with high mortality. There are few data on sex differences in CVST-VITT. The aim of our study was to investigate the differences in presentation, treatment, clinical course, complications, and outcome of CVST-VITT between women and men. Patients and methods: We used data from an ongoing international registry on CVST-VITT. VITT was diagnosed according to the Pavord criteria. We compared the characteristics of CVST-VITT in women and men. Results: Of 133 patients with possible, probable, or definite CVST-VITT, 102 (77%) were women. Women were slightly younger [median age 42 (IQR 28–54) vs 45 (28–56)], presented more often with coma (26% vs 10%) and had a lower platelet count at presentation [median (IQR) 50x109/L (28–79) vs 68 (30–125)] than men. The nadir platelet count was lower in women [median (IQR) 34 (19–62) vs 53 (20–92)]. More women received endovascular treatment than men (15% vs 6%). Rates of treatment with intravenous immunoglobulins were similar (63% vs 66%), as were new venous thromboembolic events (14% vs 14%) and major bleeding complications (30% vs 20%). Rates of good functional outcome (modified Rankin Scale 0-2, 42% vs 45%) and in-hospital death (39% vs 41%) did not differ. Discussion and conclusions: Three quarters of CVST-VITT patients in this study were women. Women were more severely affected at presentation, but clinical course and outcome did not differ between women and men. VITT-specific treatments were overall similar, but more women received endovascular treatment.</p