DNA Damage Response After Treatment of Cycling and Quiescent Cord Blood Hematopoietic Stem Cells With Distinct Genotoxic Noxae.

Hematopoietic stem cells (HSC) from cord blood can be applied as an alternative to bone marrow in transplantation to treat hematological diseases. Umbilical cord blood (UCB) consists of cycling and non-cycling CD34+/CD45low cells needed for long-term and short-term engraftment. After sorting and subsequent in vitro culture, quiescent HSCs enter the cell cycle. This enables the analysis of HSCs in 2 different cell cycle stages and the comparison of their responses to different genotoxic noxae. To analyze different mechanisms of DNA damage induction in cells, 2 different genotoxins were compared: etoposide, a topoisomerase II inhibitor that targets mitosis in the S/G2-phase of the cell cycle and the alkylating nitrosamine N-Nitroso-N-methylurea (MNU), which leads to the formation of methyl DNA adducts resulting in DNA double breaks during DNA replication and persistent mutations. Cycling cells recovered after treatment even with higher concentrations of etoposide (1.5µM/ 5µM/10µM), while sorted cells treated with MNU (0.1mM/0.3mM/0.5mM/1mM/3Mm/ 5mM) recovered after treatment with the lower MNU concentrations whereas high MNU concentrations resulted in apoptosis activation. Quiescent cells were not affected by etoposide treatment showing no damage upon entry into the cell cycle. Treatment with MNU, similarly to the cycling cells, resulted in a dose-dependent cell death. In conclusion, we found that depending on the genotoxic trigger and the cycling status, CD34+cells have distinct responses to DNA damage. Cycling cells employ both DDR and apoptosis mechanisms to prevent damage accumulation. Quiescent cells predominantly undergo apoptosis upon damage, but their cell cycle status protects them from certain genotoxic insults.

Short-Term Cessation of Dabigatran Causes a Paradoxical Prothrombotic State.

OBJECTIVE: It is unclear if stopping treatment with dabigatran, a new oral anticoagulant (NOAC), induces a paradoxical rebound prothrombotic state. We investigated if short-term (1-3 days) dabigatran cessation is associated with a higher thrombus volume than expected from a simple reversal of the anticoagulant effect. METHODS: Ten-week-old C57Bl/6 mice (n = 338) received one of the following oral treatments: phosphate-buffered saline (PBS), dabigatran for 7 days with or without 1 to 4 day cessation, and aspirin in either a single dose or daily for 7 days. Some of the animals that ceased dabigatran for 1 to 3 days received single-dose aspirin. Thereafter, we induced FeCl3 -mediated carotid thrombosis in 130 mice, after which we performed micro computed tomography thrombus imaging. The other 208 mice underwent coagulation assays or platelet function tests. As an explorative pilot study, we reviewed the medical records of 18 consecutive patients with NOAC cessation-related cerebral infarction in a large acute stroke cohort. RESULTS: We observed a ~ 40% higher volume of carotid thrombus after dabigatran cessation at 1 to 3 days than after vehicle treatment and showed that this effect could be prevented by single-dose aspirin pretreatment. Dabigatran cessation unduly increased platelet aggregability for 2 days after drug cessation, an effect mediated through thrombin or arachidonic acid, which effect was significantly attenuated by single-dose aspirin pretreatment. In patients, short-term (≤ 3 days) cessation of NOAC therapy, compared with longer-term (≥ 5 days) cessation, tended to be associated with relatively high stroke severity. INTERPRETATION: We provide the first preclinical evidence that a rebound prothrombotic state follows short-term cessation of dabigatran therapy. ANN NEUROL 2021;89:444-458.

Threat Prediction from Schemas as a Source of Bias in Pain Perception.

Our sensory impressions of pain are generally thought to represent the noxious properties of an agent but can be influenced by the predicted level of threat. Predictions can be sourced from higher-order cognitive processes, such as schemas, but the extent to which schemas can influence pain perception relative to bottom-up sensory inputs and the underlying neural underpinnings of such a phenomenon are unclear. Here, we investigate how threat predictions generated from learning a cognitive schema lead to inaccurate sensory impressions of the pain stimulus. Healthy male and female participants first detected a linear association between cue values and stimulus intensity and rated pain to reflect the linear schema when compared with uncued heat stimuli. The effect of bias on pain ratings was reduced when prediction errors (PEs) increased, but pain perception was only partially updated when measured against stepped increases in PEs. Cognitive, striatal, and sensory regions graded their responses to changes in predicted threat despite the PEs (p < 0.05, corrected). Individuals with more catastrophic thinking about pain and with low mindfulness were significantly more reliant on the schema than on the sensory evidence from the pain stimulus. These behavioral differences mapped to variability in responses of the striatum and ventromedial prefrontal cortex. Thus, this study demonstrates a significant role of higher-order schemas in pain perception and indicates that pain perception is biased more toward predictions and less toward nociceptive inputs in individuals who report less mindfulness and more fear of pain.SIGNIFICANCE STATEMENT This study demonstrates that threat predictions generated from cognitive schemas continue to influence pain perception despite increasing prediction errors arising in pain pathways. Individuals first formed a cognitive schema of linearity in the relationship between the cued threat value and the stimulus intensity. Subsequently, the linearity was reduced gradually, and participants partially updated their evaluations of pain in relation to the stepped increases in prediction errors. Individuals who continued to rate pain based more on the predicted threat than on changes in nociceptive inputs reported high pain catastrophizing and less mindful-awareness scores. These two affects mapped to activity in the ventral and dorsal striatum, respectively. These findings direct us to a significant role of top-down processes in pain perception.

Influence of Sliding Time Window Size Selection Based on Heart Rate Variability Signal Analysis on Intelligent Monitoring of Noxious Stimulation under Anesthesia.

In recent decades, little progress of objective evaluation of pain and noxious stimulation has been achieved under anesthesia. Some researches based on medical signals have failed to provide a general understanding of this problem. This paper presents a feature extraction method for heart rate variability signals, aiming at further improving the evaluation of noxious stimulation. In the process of data processing, the empirical mode decomposition is used to decompose and recombine heart rate variability signals, and the sliding time window approach is used to extract the signal features of noxious stimulation, respectively. The influence of window size on feature extraction is studied by changing the window size. By comparing the results, the feature extraction in the process of data processing is valuable, and the selection of window size has a significant impact. With the increase of selected window sizes, we can get better detection results. But for the best choice of window size, to ensure the accuracy of the results and to make it easy to use, then, we need to get just a suitable window size.

Developmental biology meets toxicology: contributing reproductive mechanisms to build adverse outcome pathways.

An adverse outcome pathway (AOP) is a simplified description of the sequence of mechanistic events that lead to a particular toxicological effect, from initial trigger to adverse outcome. Although designed to inform regulatory risk assessors, the AOP framework also provides a platform for innovative collaborations between experts from relevant research fields and the regulatory community. The underpinning for any AOP is basic knowledge about molecular and developmental processes; such knowledge can only be attained by solid bioscientific research. Starting with this fundamental knowledge, the objective is to devise novel testing strategies that focus on key events in a causative pathway. It is anticipated that such a knowledge-based approach will ultimately alleviate many of the burdens associated with classical chemical testing strategies that typically involve large-scale animal toxicity regimens. This hails from the notion that a solid understanding of the underlying mechanisms will allow the development and use of alternative test methods, including both in vitro and in silico approaches. This review is specifically targeted at professionals working in bioscientific fields, such as developmental and reproductive biology, and aims to (i) inform on the existence of the AOP framework and (ii) encourage new cross-disciplinary collaborations. It is hoped that fundamental biological knowledge can thus be better exploited for applied purposes: firstly, an improved understanding of how our perpetual exposure to environmental chemicals is causing human reproductive disease and, secondly, new approaches to screen for harmful chemicals more efficiently. This is not an instructional manual on how to create AOPs; rather, we discuss how to harness fundamental knowledge from the biosciences to assist regulatory toxicologists in their efforts to protect humans against chemicals that harm human reproductive development and function.

Cellular damage, including wounding, drives C. elegans stress-induced sleep.

Across animal phyla, sleep is associated with increased cellular repair, suggesting that cellular damage may be a core component of sleep pressure. In support of this notion, sleep in the nematode Caenorhabditis elegans can be triggered by damaging conditions, including noxious heat, high salt, and ultraviolet light exposure. It is not clear, however, whether this stress-induced sleep (SIS) is a direct consequence of cellular damage, or of a resulting energy deficit, or whether it is triggered simply by the sensation of noxious conditions. Here, we show that thermosensation is dispensable for heat-induced sleep, that osmosensation is dispensable for salt-induced sleep, and that wounding is also a sleep trigger, together indicating that SIS is not triggered by sensation of noxious environments. We present evidence that genetic variation in cellular repair pathways impacts sleep amount, and that SIS involves systemic monitoring of cellular damage. We show that the low-energy sensor AMP-activated protein kinase (AMPK) is not required for SIS, suggesting that energy deficit is not the primary sleep trigger. Instead, AMPK-deficient animals display enhanced SIS responses, and pharmacological activation of AMPK reduces SIS, suggesting that ATP-dependent repair of cellular damage mitigates sleep pressure.

Modality-specific thalamocortical inputs instruct the identity of postsynaptic L4 neurons.

During development, thalamocortical (TC) input has a critical role in the spatial delineation and patterning of cortical areas, yet the underlying cellular and molecular mechanisms that drive cortical neuron differentiation are poorly understood. In the primary (S1) and secondary (S2) somatosensory cortex, layer 4 (L4) neurons receive mutually exclusive input originating from two thalamic nuclei: the ventrobasalis (VB), which conveys tactile input, and the posterior nucleus (Po), which conveys modulatory and nociceptive input. Recently, we have shown that L4 neuron identity is not fully committed postnatally, implying a capacity for TC input to influence differentiation during cortical circuit assembly. Here we investigate whether the cell-type-specific molecular and functional identity of L4 neurons is instructed by the origin of their TC input. Genetic ablation of the VB at birth resulted in an anatomical and functional rewiring of Po projections onto L4 neurons in S1. This induced acquisition of Po input led to a respecification of postsynaptic L4 neurons, which developed functional molecular features of Po-target neurons while repressing VB-target traits. Respecified L4 neurons were able to respond both to touch and to noxious stimuli, in sharp contrast to the normal segregation of these sensory modalities in distinct cortical circuits. These findings reveal a behaviourally relevant TC-input-type-specific control over the molecular and functional differentiation of postsynaptic L4 neurons and cognate intracortical circuits, which instructs the development of modality-specific neuronal and circuit properties during corticogenesis.

The in vitro cytotoxic, genotoxic, and oxidative damage potentials of the oral artificial sweetener aspartame on cultured human blood cells

Background/aim: Aspartame (APM, L-aspartyl-L-phenylalanine methylester) is a low-calorie, nonsaccharide artificial sweetener widely used in foods and beverages. When metabolized by the body, APM is broken down into aspartic acid, phenylalanine amino acids, and a third substance, methanol. Since the amino acid phenylalanine serves as a neurotransmitter building block affecting the brain, and methanol is converted into toxic formaldehyde, APM has deleterious effects on the body and brain. Thus, its safety and, toxicity have been the subjects of concern ever since it was first discovered. Although many studies have been performed on it, due to the presence of conflicting data in the literature, there are still numerous question marks concerning APM.Therefore, the safety of aspartame was tested using in vitro methods. Materials and methods: We aimed to evaluate the in vitro cytotoxic effects by using 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase release tests, genotoxic damage potential by using chromosome aberration (CA) assay, and antioxidant/oxidant activity by using total antioxidant capacity (TAC) and total oxidative stress (TOS) analysis in primary human whole blood cell cultures. Results: The results of the MTT test showed that APM led to significant decreases in cell viability in a clear concentration-dependent manner. Moreover, an increase in CA frequency was found in the cells treated with APM. However, APM treatments did not cause any significant changes in TAC and TOS levels in whole blood cultures. Conclusion: Overall, the obtained results showed that APM had genotoxicity potential and a concentration-dependent cytotoxic activity in human blood cells.

[COPD due to Occupational Noxae]. / COPD durch berufliche Noxen.

The chronic obstructive pulmonary disease (COPD) is characterised by mainly non-reversible bronchial obstruction with airflow limitation. Typically, it exhibits a progressive course. It is one of the leading causes of morbidity and mortality worldwide. In addition to dominating causative smoking and environmental exposures (especially biomass smoke from cooking with open fire stoves), about 15 % are due to occupational exposure. Relatively rare cases (ca. 6 %) do not show an external noxious influence. Occupational causes are frequently not recognised because a detailed occupational history has not been taken. This is especially evident by the discrepancy in the identified COPD prevalences and incidences shown in many studies on the one hand and relatively low numbers in the official statistics on reports, acknowledgements and compensations of the disorder on the other hand. Whether occupational exposures to inhalative noxae are - in addition to non-occupational factors (e. g. smoking) - causative according to legal definitions is frequently a challenging question. Respective decisions of social courts in litigations are presented.

Prediction of the Toxicity of Binary Mixtures by QSAR Approach Using the Hypothetical Descriptors.

Organic compounds are often exposed to the environment, and have an adverse effect on the environment and human health in the form of mixtures, rather than as single chemicals. In this paper, we try to establish reliable and developed classical quantitative structure⁻activity relationship (QSAR) models to evaluate the toxicity of 99 binary mixtures. The derived QSAR models were built by forward stepwise multiple linear regression (MLR) and nonlinear radial basis function neural networks (RBFNNs) using the hypothetical descriptors, respectively. The statistical parameters of the MLR model provided were N (number of compounds in training set) = 79, R² (the correlation coefficient between the predicted and observed activities)= 0.869, LOOq² (leave-one-out correlation coefficient) = 0.864, F (Fisher's test) = 165.494, and RMS (root mean square) = 0.599 for the training set, and Next (number of compounds in external test set) = 20, R² = 0.853, qext2 (leave-one-out correlation coefficient for test set)= 0.825, F = 30.861, and RMS = 0.691 for the external test set. The RBFNN model gave the statistical results, namely N = 79, R² = 0.925, LOOq² = 0.924, F = 950.686, RMS = 0.447 for the training set, and Next = 20, R² = 0.896, qext2 = 0.890, F = 155.424, RMS = 0.547 for the external test set. Both of the MLR and RBFNN models were evaluated by some statistical parameters and methods. The results confirm that the built models are acceptable, and can be used to predict the toxicity of the binary mixtures.

Reduction in activity by noxious chemical stimulation is ameliorated by immersion in analgesic drugs in zebrafish.

Research has recently demonstrated that larval zebrafish show similar molecular responses to nociception to those of adults. Our study explored whether unprotected larval zebrafish exhibited altered behaviour after exposure to noxious chemicals and screened a range of analgesic drugs to determine their efficacy to reduce these responses. This approach aimed to validate larval zebrafish as a reliable replacement for adults as well as providing a high-throughput means of analysing behavioural responses. Zebrafish at 5 days post-fertilization were exposed to known noxious stimuli: acetic acid (0.01%, 0.1% and 0.25%) and citric acid (0.1%, 1% and 5%). The behavioural response of each was recorded and analysed using novel tracking software that measures time spent active in 25 larvae at one time. Subsequently, the efficacy of aspirin, lidocaine, morphine and flunixin as analgesics after exposure to 0.1% acetic acid was tested. Larvae exposed to 0.1% and 0.25% acetic acid spent less time active, whereas those exposed to 0.01% acetic acid and 0.1-5% citric acid showed an increase in swimming activity. Administration of 2.5 mg l-1 aspirin, 5 mg l-1 lidocaine and 48 mg l-1 morphine prevented the behavioural changes induced by acetic acid. These results suggest that larvae respond to a noxious challenge in a similar way to adult zebrafish and other vertebrates and that the effect of nociception on activity can be ameliorated by using analgesics. Therefore, adopting larval zebrafish could represent a direct replacement of a protected adult fish with a non-protected form in pain- and nociception-related research.

Analysis of the role of von Willebrand factor, platelet glycoprotein VI-, and α2ß1-mediated collagen binding in thrombus formation.

Rare missense mutations in the von Willebrand factor (VWF) A3 domain that disrupt collagen binding have been found in patients with a mild bleeding phenotype. However, the analysis of these aberrant VWF-collagen interactions has been limited. Here, we have developed mouse models of collagen-binding mutants and analyzed the function of the A3 domain using comprehensive in vitro and in vivo approaches. Five loss-of-function (p.S1731T, p.W1745C, p.S1783A, p.H1786D, A3 deletion) and 1 gain-of-function (p.L1757A) variants were generated in the mouse VWF complementary DNA. The results of these various assays were consistent, although the magnitude of the effects were different: the gain-of-function (p.L1757A) variant showed consistent enhanced collagen binding whereas the loss-of-function mutants showed variable degrees of functional deficit. We further analyzed the impact of direct platelet-collagen binding by blocking glycoprotein VI (GPVI) and integrin α2ß1 in our ferric chloride murine thrombosis model. The inhibition of GPVI demonstrated a comparable functional defect in thrombosis formation to the VWF(-/-) mice whereas α2ß1 inhibition demonstrated a milder bleeding phenotype. Furthermore, a delayed and markedly reduced thrombogenic response was still evident in VWF(-/-), GPVI, and α2ß1 blocked animals, suggesting that alternative primary hemostatic mechanisms can partially rescue the bleeding phenotype associated with these defects.

[Investigation of the liver DNA methylation profile of rats under the influence of hepatotoxicants of different nature].

The functional importance of DNA methylation, which is a special case of epigenetic variation, is meant for regulation of many biological processes, ranged from tissue specific gene expression to remodeling of chromatin structure. Disorders of the DNA methylation can cause changes in the cell's phenotype, providing a significant impact on the development of pathology. Both exogenous and endogenous factors are able to cause disruption of DNA methylation, while epigenetic changes usually precede the emergence of clinical and morphological symptoms of pathological process development, consequently the parameters of DNA methylation can be used as sensitive biomarkers to detect adverse effects on the organism. The purpose of the study was to identify genes of the liver, the methylation profile of which changes under the influence of hepatotoxicants of different nature. The experiment was carried out on 60 male Wistar rats with initial body weight (b.w.) 83.3±1.5 g. Animals were randomly divided into 6 groups - 1 control and 5 test groups, with 10 rats in each group. During the first two weeks of the experiment the rats of the 1-5th test groups were administered to aflatoxin B1 (200 Mg/kg b.w.), cadmium chloride 2,5-hydrate (2 mg/kg), monosodium glutamate (1000 mg/kg), epigallocatechin gallate (EGCG) (1000 mg/kg), paracetamol (150 mg/kg), accordingly. Methylation of the liver genes in rats was determined by using high-performance methods, based on bisulfite sequencing of reduced representation. For each sample from 12 to 30 million pairs of reads were received, genes which demonstrated significant changes in methylation when exposed to toxic factors were identified: aflatoxin B1 caused changes in the methylation of 57 genes; cadmium - 54 genes; monosodium glutamate - 39 genes; EGCG -198 genes; paracetamol - 167 genes. The comparison of genes with altered methylation in the experimental groups revealed that none of the genes repeatedly occurred under the influence of each toxicant out of five, the highest number of repeats accounted 3. As a result of the present analysis 7 genes have been selected: methylation change in Fan1 gene was observed when exposed to cadmium, monosodium glutamate, EGCG; gene Lppr2 - under the influence of aflatoxin B1, EGCG, paracetamol; gene Mlh3 - under the influence of aflatoxin B1, cadmium, paracetamol; Sirt7 gene - under the influence of cadmium, EGCG, paracetamol; gene Fbxo15 - when exposed to cadmium, monosodium glutamate, paracetamol; gene E2f1 - when exposed to cadmium, EGCG, paracetamol; gene Mrps16 - when exposed to cadmium, EGCG, paracetamol. On the basis of the received data the project of the panel of genes-biomarkers of toxic effect, including genes Fan1, Lppr2, Mlh3, Sirt7, Fbxo15, E2f1, Mrps16 has been formed.

Desmolaris, a novel factor XIa anticoagulant from the salivary gland of the vampire bat (Desmodus rotundus) inhibits inflammation and thrombosis in vivo.

The identity of vampire bat saliva anticoagulant remained elusive for almost a century. Sequencing the salivary gland genes from the vampire bat Desmodus rotundus identified Desmolaris as a novel 21.5-kDa naturally deleted (Kunitz 1-domainless) form of tissue factor pathway inhibitor. Recombinant Desmolaris was expressed in HEK293 cells and characterized as a slow, tight, and noncompetitive inhibitor of factor (F) XIa by a mechanism modulated by heparin. Desmolaris also inhibits FXa with lower affinity, independently of protein S. In addition, Desmolaris binds kallikrein and reduces bradykinin generation in plasma activated with kaolin. Truncated and mutated forms of Desmolaris determined that Arg32 in the Kunitz-1 domain is critical for protease inhibition. Moreover, Kunitz-2 and the carboxyl-terminus domains mediate interaction of Desmolaris with heparin and are required for optimal inhibition of FXIa and FXa. Notably, Desmolaris (100 µg/kg) inhibited FeCl3-induced carotid artery thrombus without impairing hemostasis. These results imply that FXIa is the primary in vivo target for Desmolaris at antithrombotic concentrations. Desmolaris also reduces the polyphosphate-induced increase in vascular permeability and collagen- and epinephrine-mediated thromboembolism in mice. Desmolaris emerges as a novel anticoagulant targeting FXIa under conditions in which the coagulation activation, particularly the contact pathway, plays a major pathological role.

Lifelong occupational exposures and hearing loss among elderly Latino Americans aged 65-75 years.

OBJECTIVE: The purpose of this study is to determine the relationship between occupational exposures and hearing among elderly Latino Americans. DESIGN: A descriptive, correlational design used for this secondary analysis with the data from the Sacramento Area Latino Study of Aging (SALSA). STUDY SAMPLE: A total of 547 older adults were included. RESULTS: A majority of participants (58%) reported occupational exposures to loud noise and/or ototoxic chemicals. About 65% and over 90% showed hearing loss at low and high frequencies, respectively. Participants with occupational exposure to loud noise and/or ototoxic chemicals were, significantly, two times more likely to have hearing loss at high frequencies compared to those without exposure (OR = 2.29; 95% CI: 1.17 = 4.51, p = .016), after controlling for other risk factors of hearing loss such as age, gender, household income, current smoking, and diabetes. However, lifelong occupational exposure was not significantly associated with hearing loss at low frequencies (OR = 1.43; 95% CI: 0.94 = 2.18, p = .094). CONCLUSION: Lifelong occupational exposure to loud noise and/or ototoxic chemicals was significantly associated with hearing loss among elderly Latino Americans. Healthy work life through protection from harmful auditory effects of occupational exposures to noise and chemicals will have a positive impact on better hearing in later life.

Removal of soluble microbial products as the precursors of disinfection by-products in drinking water supplies.

Water pollution worsens the problem of disinfection by-products (DBPs) in drinking water supply. Biodegradation of wastewater organics produces soluble microbial products (SMPs), which can be important DBP precursors. In this laboratory study, a number of enhanced water treatment methods for DBP control, including enhanced coagulation, ozonation, and activated carbon adsorption, were evaluated for their effectiveness in treating SMP-containing water for the DBP reduction purpose. The results show that enhanced coagulation with alum could remove SMPs only marginally and decrease the DBP formation potential (DBPFP) of the water by less than 20%. Although ozone could cause destruction of SMPs in water, the overall DBPFP of the water did not decrease but increased after ozonation. In contrast, adsorption by granular activated carbon could remove the SMP organics from water by more than 60% and reduce the DBPFP by more than 70%. It is apparent that enhanced coagulation and ozonation are not suitable for the removal of SMPs as DBP precursors from polluted water, although enhanced coagulation has been commonly used to reduce the DBP formation caused by natural organic matter. In comparison, activated carbon adsorption is shown as a more effective means to remove the SMP content from water and hence to control the wastewater-derived DBP problem in water supply.

Pistacia Terebinthus Coffee Protects against Thioacetamide-Induced Liver Injury in Rats.

AIM/BACKGROUND: Pistacia terebinthus is used as a coffee substitute in the East and Southern Anatolia regions of Turkey. It contains unsaturated fatty acids, tocopherols, polyphenols and carotenoids. P. terebinthus has anti-inflammatory and potential antioxidant activity. In this study we evaluated the protective effects of P. terebinthus coffee (PTC) on thioacetamide (TAA)-induced liver injury in rats. MATERIALS AND METHODS: Twenty-eight male Sprague-Dawley rats were equally randomized into four groups. Chronic liver injury was induced with TAA (100 mg/kg i.p. three times weekly). The first group of rats served as control and received only tap water (G1), and the remaining groups of rats received PTC, p.o (G2); TAA (G3); TAA plus PTC, p.o (G4), respectively. RESULTS: After 8 weeks, PTC intake significantly reduced fibrosis/inflammation scores (p PTC intake reduced transforming growth factor beta (TGF-ß) concentrations in the liver (p PTC intake. DISCUSSION AND CONCLUSION: PTC intake provided beneficial effects against TAA-induced liver injury in rats. PTC probably suppresses the proinflammatory cytokines through NF-κB signaling pathway.

Regulation of HFE expression by poly(ADP-ribose) polymerase-1 (PARP1) through an inverted repeat DNA sequence in the distal promoter.

Hereditary hemochromatosis (HH) is a common autosomal recessive disorder of iron overload among Caucasians of northern European descent. Over 85% of all cases with HH are due to mutations in the hemochromatosis protein (HFE) involved in iron metabolism. Although the importance in iron homeostasis is well recognized, the mechanism of sensing and regulating iron absorption by HFE, especially in the absence of iron response element in its gene, is not fully understood. In this report, we have identified an inverted repeat sequence (ATGGTcttACCTA) within 1700bp (-1675/+35) of the HFE promoter capable to form cruciform structure that binds PARP1 and strongly represses HFE promoter. Knockdown of PARP1 increases HFE mRNA and protein. Similarly, hemin or FeCl3 treatments resulted in increase in HFE expression by reducing nuclear PARP1 pool via its apoptosis induced cleavage, leading to upregulation of the iron regulatory hormone hepcidin mRNA. Thus, PARP1 binding to the inverted repeat sequence on the HFE promoter may serve as a novel iron sensing mechanism as increased iron level can trigger PARP1 cleavage and relief of HFE transcriptional repression.

Elevated prothrombin promotes venous, but not arterial, thrombosis in mice.

OBJECTIVE: Individuals with elevated prothrombin, including those with the prothrombin G20210A mutation, have increased risk of venous thrombosis. Although these individuals do not have increased circulating prothrombotic biomarkers, their plasma demonstrates increased tissue factor-dependent thrombin generation in vitro. The objectives of this study were to determine the pathological role of elevated prothrombin in venous and arterial thrombosis in vivo, and distinguish thrombogenic mechanisms in these vessels. APPROACH AND RESULTS: Prothrombin was infused into mice to raise circulating levels. Venous thrombosis was induced by electrolytic stimulus to the femoral vein or inferior vena cava ligation. Arterial thrombosis was induced by electrolytic stimulus or ferric chloride application to the carotid artery. Mice infused with prothrombin demonstrated increased tissue factor-triggered thrombin generation measured ex vivo, but did not have increased circulating prothrombotic biomarkers in the absence of vessel injury. After venous injury, elevated prothrombin increased thrombin generation and the fibrin accumulation rate and total amount of fibrin ≈ 3-fold, producing extended thrombi with increased mass. However, elevated prothrombin did not accelerate platelet accumulation, increase the fibrin accumulation rate, or shorten the vessel occlusion time after arterial injury. CONCLUSIONS: These findings reconcile previously discordant findings on thrombin generation in hyperprothrombinemic individuals measured ex vivo and in vitro, and show elevated prothrombin promotes venous, but not arterial, thrombosis in vivo.