Hyperthermia-induced changes in leukocyte survival and phagocytosis: a comparative study in bovine and buffalo leukocytes

Heat stress negatively affects health, welfare, and livestock productivity by impairing immune function, increasing disease incidence. In recent years, there has been increasing interest in understanding the immune system of water buffalo due to the growing economic impact of this species for the high quality and nutritional value of buffalo milk. While there are common responses across bovine and buffalo species, there are also some species-specific variations in the physiological responses to heat stress, mainly attributed to differences in metabolism and heat dissipation efficiency. At cellular level, the exposure to thermal stress induces several anomalies in cell functions. However, there is limited knowledge about the differential response of bovine and buffalo leucocytes to early and late exposure to different degrees of thermal exposure. The aim of this study was to compare the in vitro effect of hyperthermia on apoptosis and phagocytosis in leukocytes from bovine and buffalo species. For this, whole blood samples of six bovines and nine buffaloes were incubated at 39°C (mimicking normothermia condition) or 41°C (mimicking heat stress condition) for 1, 2, and 4 h. Two flow cytometric assays were then performed to evaluate apoptosis and determine functional capacity of phagocytic cells (neutrophils and monocytes). The results showed that the viability of bovine and buffalo leukocytes was differently affected by temperature and time of in vitro exposure. A higher percentage of apoptotic leukocytes was observed in bovines than in buffaloes at 39°C (3.19 vs. 1.51, p < 0.05) and 41°C (4.01 vs. 1.69, p < 0.05) and for all incubation time points (p < 0.05). In contrast, no difference was observed in the fraction of necrotic leukocytes between the two species. In both species, lymphocytes showed the highest sensitivity to hyperthermia, showing an increased apoptosis rates along with increased incubation time. In bovine, apoptotic lymphocytes increased from 5.79 to 12.7% at 39°C (p < 0.05), in buffalo, this population increased from 1.50 to 3.57% at 39°C and from 2.90 to 4.99% at 41°C (p < 0.05). Although no significant differences were found between the two species regarding the percentage of phagocytic neutrophils, lower phagocytosis capacity values (MFI, mean fluorescence intensity) were found in bovines compared with buffaloes at 41°C (27960.72 vs. 53676.45, p > 0.05). However, for monocytes, the differences between species were significant for both phagocytosis activity and capacity with lower percentages of bovine phagocytic monocytes after 2 h at 39°C and after 1 h at 41°C. The bovine monocytes showed lower MFI values for all temperature and time variations than buffaloes (37538.91 vs. 90445.47 at 39°C and 33752.91 vs. 70278.79 at 41°C, p < 0.05). In conclusion, the current study represents the first report on the comparative analysis of the effect of in vitro heat stress on bovine and buffalo leukocyte populations, highlighting that the leukocytes of buffalo exhibit relatively higher thermal adaptation than bovine cells.

Quadrato Motor Training (QMT) is associated with DNA methylation changes at DNA repeats: A pilot study

The control of non-coding repeated DNA by DNA methylation plays an important role in genomic stability, contributing to health and healthy aging. Mind-body practices can elicit psychophysical wellbeing via epigenetic mechanisms, including DNA methylation. However, in this context the effects of movement meditations have rarely been examined. Consequently, the current study investigates the effects of a specifically structured movement meditation, called the Quadrato Motor Training (QMT) on psychophysical wellbeing and on the methylation level of repeated sequences. An 8-week daily QMT program was administered to healthy women aged 40-60 years and compared with a passive control group matched for gender and age. Psychological well-being was assessed within both groups by using self-reporting scales, including the Meaning in Life Questionnaire [MLQ] and Psychological Wellbeing Scale [PWB]). DNA methylation profiles of repeated sequences (ribosomal DNA, LINE-1 and Alu) were determined in saliva samples by deep-sequencing. In contrast to controls, the QMT group exhibited increased Search for Meaning, decreased Presence of Meaning and increased Positive Relations, suggesting that QMT may lessen the automatic patterns of thinking. In the QMT group, we also found site-specific significant methylation variations in ribosomal DNA and LINE-1 repeats, consistent with increased genome stability. Finally, the correlations found between changes in methylation and psychometric indices (MLQ and PWB) suggest that the observed epigenetic and psychological changes are interrelated. Collectively, the current results indicate that QMT may improve psychophysical health trajectories by influencing the DNA methylation of specific repetitive sequences.

Simulated Microgravity Exposure Induces Antioxidant Barrier Deregulation and Mitochondria Enlargement in TCam-2 Cell Spheroids

One of the hallmarks of microgravity-induced effects in several cellular models is represented by the alteration of oxidative balance with the consequent accumulation of reactive oxygen species (ROS). It is well known that male germ cells are sensitive to oxidative stress and to changes in gravitational force, even though published data on germ cell models are scarce. We previously studied the effects of simulated microgravity (s-microgravity) on a 2D cultured TCam-2 seminoma-derived cell line, considered the only human cell line available to study in vitro mitotically active human male germ cells. In this study, we used a corresponding TCam-2 3D cell culture model that mimics cell-cell contacts in organ tissue to test the possible effects induced by s-microgravity exposure. TCam-2 cell spheroids were cultured for 24 h under unitary gravity (Ctr) or s-microgravity conditions, the latter obtained using a random positioning machine (RPM). A significant increase in intracellular ROS and mitochondria superoxide anion levels was observed after RPM exposure. In line with these results, a trend of protein and lipid oxidation increase and increased pCAMKII expression levels were observed after RPM exposure. The ultrastructural analysis via transmission electron microscopy revealed that RPM-exposed mitochondria appeared enlarged and, even if seldom, disrupted. Notably, even the expression of the main enzymes involved in the redox homeostasis appears modulated by RPM exposure in a compensatory way, with GPX1, NCF1, and CYBB being downregulated, whereas NOX4 and HMOX1 are upregulated. Interestingly, HMOX1 is involved in the heme catabolism of mitochondria cytochromes, and therefore the positive modulation of this marker can be associated with the observed mitochondria alteration. Altogether, these data demonstrate TCam-2 spheroid sensitivity to acute s-microgravity exposure and indicate the capability of these cells to trigger compensatory mechanisms that allow them to overcome the exposure to altered gravitational force.

YY1 Knockdown Relieves the Differentiation Block and Restores Apoptosis in AML Cells

In this study we analyzed the expression of Yin and Yang 1 protein (YY1), a member of the noncanonical PcG complexes, in AML patient samples and AML cell lines and the effect of YY1 downregulation on the AML differentiation block. Our results show that YY1 is significantly overexpressed in AML patient samples and AML cell lines and that YY1 knockdown relieves the differentiation block. YY1 downregulation in two AML cell lines (HL-60 and OCI-AML3) and one AML patient sample restored the expression of members of the CEBP protein family, increased the expression of extrinsic growth factors/receptors and surface antigenic markers, induced morphological cell characteristics typical of myeloid differentiation, and sensitized cells to retinoic acid treatment and to apoptosis. Overall, our data show that YY1 is not a secondary regulator of myeloid differentiation but that, if overexpressed, it can play a predominant role in myeloid differentiation block.

Uncovering the Relationship between Selenium Status, Age, Health, and Dietary Habits: Insights from a Large Population Study including Nonagenarian Offspring from the MARK-AGE Project

An inadequate selenium (Se) status can accelerate the aging process, increasing the vulnerability to age-related diseases. The study aimed to investigate plasma Se and Se species in a large population, including 2200 older adults from the general population (RASIG), 514 nonagenarian offspring (GO), and 293 GO Spouses (SGO). Plasma Se levels in women exhibit an inverted U-shaped pattern, increasing with age until the post-menopausal period and then declining. Conversely, men exhibit a linear decline in plasma Se levels with age. Subjects from Finland had the highest plasma Se values, while those from Poland had the lowest ones. Plasma Se was influenced by fish and vitamin consumption, but there were no significant differences between RASIG, GO, and SGO. Plasma Se was positively associated with albumin, HDL, total cholesterol, fibrinogen, and triglycerides and negatively associated with homocysteine. Fractionation analysis showed that Se distribution among plasma selenoproteins is affected by age, glucometabolic and inflammatory factors, and being GO or SGO. These findings show that sex-specific, nutritional, and inflammatory factors play a crucial role in the regulation of Se plasma levels throughout the aging process and that the shared environment of GO and SGO plays a role in their distinctive Se fractionation.

Incidence of stroke in patients with hypertrophic cardiomyopathy in stable sinus rhythm during long-term monitoring

Background

Patients with hypertrophic cardiomyopathy (HCM) are at increased risk of atrial fibrillation (AF) and stroke, especially at an advanced disease stage. To date, however, the incidence and factors associated with cardioembolic events in HCM patients without AF remain unresolved.

Purpose

To determine the incidence of stroke in HCM patients in whom cardiac rhythm was monitored with a cardiac implantable electronic device (CIED). The association of stroke with left atrial (LA) enlargement was also examined.

Methods

Retrospective cohort study in an outpatient clinic in a tertiary HCM Referral Center.

All consecutive patients diagnosed with HCM and referred for CIED implantation with &gt;16 years at diagnosis and &gt;1 year follow-up post CIED implantation were reviewed. Severe LA dilatation was defined as a LA dimension (LAD) of &gt;48mm at echocardiogram. Based on CIED monitoring, patients were classified as: Pre-existing AF (diagnosed with AF prior to CIED); De novo AF (diagnosed with AF after CIED implantation); Sinus Rhythm (SR): no episodes of AF. Incidence of stroke after CIED implantation was the primary outcome.

Results

A total of 185 patients (57% men, age: 54±17 years) were implanted with a CIED and were included. Pre-existing AF was present in 72 (36%) patients and de novo AF in 24 (13%); whereas 89 (48%) remained in SR. After 5 [2–9] years, stroke was reported in 19 (10.3%) patients: 7 occurred in patients with pre-existing AF (1.1%/year), 3 in patients with de novo AF (2.2%/year), and 9 in patients with SR (2.3%/year). No difference was captured by CHA2DS2-VASc score among rhythm categories. Patients with AF had larger LAD at baseline. Among patients in SR, those with a LAD&gt;48mm had the greatest risk of stroke (4.8%/year vs 0.5%/year, p&lt;0.01; Hazard Ratio [HR]: 8.56, 95% C.I. 2.03–36.15). At Cox multivariable regression analysis, LA (HR: 1.104, 95%C.I. 1.039–1.173, p=0.001) and AF (HR: 0.310, 95% C.I. 0.102–0.939, p=0.038) were associated with incident stroke.

Conclusions

In HCM patients with CIED long-term monitoring and no prior history of AF, stroke rates were similar in those with de novo AF or stable sinus rhythm. CHA2DS2-VASc considerably underestimated risk, whereas severe LA dilatation was a powerful predictor of risk, irrespective of AF.

Funding Acknowledgement

Type of funding sources: None.

Clinical scenarios of HCM-related mortality: relevance of age and stage of disease at presentation

 

In the early days, Hypertrophic cardiomyopathy (HCM) has long been considered a malignant disease.

However, contemporary descriptions of HCM report low mortality rates, largely due to heart failure-related complications (HF), while sudden cardiac death (SCD) rates are consistently low. Ageing with HCM is not uncommon and competing risk of acquired cardiovascular (CV) and non-CV diseases becomes relevant over time.

Purpose

To describe the disease stage at presentation and the modes of death in a cohort of consecutive HCM patients followed at a national referral centre over the last two decades. Stages of disease were defined according to Circ. Heart Fail. 2012, as follows:

1) “Classic HCM phenotype” characterized by LV ejection fraction (EF) &gt;65%.

2) “Adverse remodeling” characterized by LVEF in the range of 50% to 65%.

3) “Overt dysfunction” is the end-stage clinical evolution characterized by a LVEF &lt;50%.

Methods

By searching our centralized database, we identified 1491 HCM patients with at least &gt;1 year of follow-up between January 2000 and December 2020, 191 of whom died in the same period. In 30 the cause of death could not be ascertained. The remaining 161 constituted our study cohort.

Results

Of the 161 patients who died, 103 (64%) died due to HCM-related causes, whereas 58 (36%) died from non-HCM-related causes such as coronary artery disease (other CV) or other non CV causes.

Modes of death varied based on the stage of disease at diagnosis:

– Fifty-six (35%) patients had a “classic” HCM phenotype at diagnosis. Of these, about half died of HCM-related causes (n=30; 54%), versus 45% with non-HCM-related death. Differently from the other 2 stages, the single most common cause of death was “other non-CV related” mortality, in 44%. Among HCM-related causes, SCD prevailed (n=15; 27%) while HF-related events were only 8 (14%).

– Of the 86 (53%) patients with “adverse remodeling” at diagnosis, more than half died of HCM-related causes (n=57, 66%), largely due to HF (n=33, 38%); SCD occurred in 18 (21%) individuals. This stage included the highest percentage of patients who died of stroke (n=6; 7%).

– Of the 19 (12%) patients in “overt dysfunction” at diagnosis, HF represented the cause of demise in almost three quarters (n=14, 74%); SCD and non-HCM causes accounted for only 10% and 16% respectively.

Conclusions

Most HCM patients die due to complications of their own disease, mainly in the context of HF. Modes of death vary with the stage of disease, with SCD becoming less prevalent in more advanced phases of progression, when competitive risks of HF-related events become overwhelming. These data highlight an unmet medical need in the prevention of disease progression associated with HCM.

Funding Acknowledgement

Type of funding sources: None.

Clinical, functional and prognostic correlates of excess left ventricular force in hypertrophic cardiomyopathy

Background

Excess force generation during myocardial contraction represents a cardinal feature of hypertrophic cardiomyopathy (HCM).

Purpose

To evaluate the anatomical, functional and prognostic correlates of left ventricular (LV) force in HCM.

Methods

We prospectively recruited a consecutive sample of 408 HCM patients with LV ejection fraction (EF) &gt;50%, referred for baseline transthoracic echocardiography in 2 primary HCM centers in Hungary and Italy between 1999 and 2021. LV force was calculated as LV outflow tract gradient+systolic blood pressure/LV end-systolic volume. Patients were followed for a median of 107 months (IQ range, 58–158 months), the study endpoint was all-cause mortality.

Results

Mean LV force was 6.0±4.6 mm Hg/ml. Receiver-operating characteristic analysis identified 7.5 mm Hg/ml the best cut-off value to predict mortality. LV force &gt;7.5 mm Hg/ml was present in 86 patients (21%), more frequently in women (58 vs 27%, p&lt;0.0001), more often in patients with diabetes (16 vs 6%, p=0.003), beta-blocker (81 vs 58%, p&lt;0.0001), calcium channel-blocker (19 vs 9%, p=0.012) and diuretic therapy (19 vs 8%, p=0.004), compared to patients with LV force ≤7.5 mm Hg/ml. Patients with excess LV force had more advanced NYHA class (1.8±0.7 vs 1.4±0.7, p=0.0001), greater left atrial diameter [(LAd), 46.7±6.6 vs 43.0±7.2 mm, &lt;0.0001], LV maximal wall thickness (23.2±5.5 vs 21.6±5.5 mm p=0.01), LV EF (74.6±6.4 vs 67.0±6.8%, &lt;0.0001), mitral regurgitation grade (1.2±0.7 vs 0.7±0.7, p&lt;0.0001) and E/e' (10.3±5.0 vs 7.8±5.0, p=0.005). During follow-up 43 deaths occurred. All-cause death was more frequent in patients with excess LV force (21 vs 8%, p&lt;0.0001). At multivariable Cox regression analysis, excess LV force was an independent predictor of mortality (HR 2.9, 95% CI 1.14–7.26, p=0.025) independent of age (HR 1.03, 95% CI 1.00–1.05, p=0.022) and LAd (HR 1.07, 95% CI 1.02–1.14, p=0.005).

Conclusion

LV force with a threshold of 7.5 mm Hg/ml, independently predicts adverse outcome in patients with HCM and preserved systolic function. Excess LV force generation is associated with female sex, diabetes, NYHA class, medications, LAd, LV wall thickness, EF, mitral regurgitation grade and E/e'.

Funding Acknowledgement

Type of funding sources: None.

Counteracting aged DNA methylation states to combat ageing and age-related diseases

DNA methylation (DNAm) overwrites information about multiple extrinsic factors on the genome. Age is one of these factors. Age causes characteristic DNAm changes that are thought to be not only major drivers of normal ageing but also precursors to diseases, cancer being one of these. Although there is still much to learn about the relationship between ageing, age-related diseases and DNAm, we now know how to interpret some of the effects caused by age in the form of changes in methylation marks at specific loci. In fact, these changes form the basis of the so called "epigenetic clocks", which translate the genomic methylation profile into an "epigenetic age". Epigenetic age does not only estimate chronological age but can also predict the risk of chronic diseases and mortality. Epigenetic age is believed to be one of the most accurate metrics of biological age. Initial evidence has recently been gathered pointing to the possibility that the rate of epigenetic ageing can be slowed down or even reversed. In this review, we discuss some of the most relevant advances in this field. Expected outcome is that this approach can provide insights into how to preserve health and reduce the impact of ageing diseases in humans.

DNA Methylation Analysis of Ribosomal DNA in Adults With Down Syndrome

Control of ribosome biogenesis is a critical aspect of the regulation of cell metabolism. As ribosomal genes (rDNA) are organized in repeated clusters on chromosomes 13, 14, 15, 21, and 22, trisomy of chromosome 21 confers an excess of rDNA copies to persons with Down syndrome (DS). Previous studies showed an alteration of ribosome biogenesis in children with DS, but the epigenetic regulation of rDNA genes has not been investigated in adults with DS so far. In this study, we used a targeted deep-sequencing approach to measure DNA methylation (DNAm) of rDNA units in whole blood from 69 adults with DS and 95 euploid controls. We further evaluated the expression of the precursor of ribosomal RNAs (RNA45S) in peripheral blood mononuclear cells (PBMCs) from the same subjects. We found that the rDNA promoter tends to be hypermethylated in DS concerning the control group. The analysis of epihaplotypes (the combination of methylated and unmethylated CpG sites along the same DNA molecule) showed a significantly lower intra-individual diversity in the DS group, which at the same time was characterized by a higher interindividual variability. Finally, we showed that RNA45S expression is lower in adults with DS. Collectively, our results suggest a rearrangement of the epigenetic profile of rDNA in DS, possibly to compensate for the extranumerary rDNA copies. Future studies should assess whether the regulation of ribosome biogenesis can contribute to the pathogenesis of DS and explain the clinical heterogeneity characteristic of the syndrome.

Biliverdin reductase-A protein levels are reduced in type 2 diabetes and are associated with poor glycometabolic control

AIM

Biliverdin reductase-A (BVR-A) other than its canonical role in the degradation pathway of heme as partner of heme oxygenase-1 (HO1), has recently drawn attention as a protein with pleiotropic functions involved in insulin-glucose homeostasis. However, whether BVR-A expression is altered in type 2 diabetes (T2D) has never been evaluated.

MAIN METHODS

BVR-A protein levels were evaluated in T2D (n = 44) and non-T2D (n = 29) subjects, who underwent complete clinical workup and routine biochemistry. In parallel, levels HO1, whose expression is regulated by BVR-A as well as levels of tumor necrosis factor α (TNFα), which is a known repressor for BVR-A with pro-inflammatory properties, were also assessed.

KEY FINDINGS

BVR-A levels were significantly lower in T2D subjects than in non-T2D subjects. Reduced BVR-A levels were associated with greater body mass, systolic blood pressure, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), triglycerides, transaminases and TNFα, and with lower high-density lipoprotein (HDL) levels. Lower BVR-A levels are associated with reduced HO1 protein levels and the multivariate analysis showed that BVR-A represented the main determinant of HO1 levels in T2D after adjustment. In addition, reduced BVR-A levels were able to predict the presence of T2D with AUROC = 0.69. for potential confounders.

SIGNIFICANCE

Our results demonstrate for the first time that BVR-A protein levels are reduced in T2D individuals, and that this alteration strictly correlates with poor glycometabolic control and a pro-inflammatory state. Hence, these observations reinforce the hypothesis that reduced BVR-A protein levels may represent a key event in the dysregulation of intracellular pathways finally leading to metabolic disorders.

Tenosynovial complications identify TTR cardiac amyloidosis among patients with hypertrophic cardiomyopathy phenotype

Recent evidence suggests that carpal tunnel syndrome (CTS) and brachial biceps tendon rupture (BBTR) represent red flags for ATTR cardiac amyloidosis (ATTR-CA). The prevalence of upper limb tenosynovial complications in conditions entering differential diagnosis with CA, such as HCM or Anderson-Fabry disease (AFD), and hence their predictive accuracy in this setting, still remains unresolved.

OBJECTIVE

To investigate the prevalence of CTS and BBTR in a consecutive cohort of ATTR-CA patients, compared with patients with HCM or AFD and with individuals without cardiac disease history.

PARTICIPANTS

Consecutive patients with a diagnosis of ATTR-CA, HCM and AFD were evaluated. A control group of consecutive patients was recruited among subjects hospitalized for noncardiac reasons and no cardiac disease history. The presence of BBTR, CTS or prior surgery related to these conditions was ascertained.

RESULTS

342 patients were prospectively enrolled, including 168 ATTR-CA (141 ATTRwt, 27 ATTRm), 81 with HCM/AFD (N = 72 and 9, respectively) and 93 controls. CTS was present in 75% ATTR-CA patients, compared with 13% and 10% of HCM/AFD and controls (P = 0.0001 for both comparisons). Bilateral CTS was present in 60% of ATTR-CA patients, while it was rare (2%) in the other groups. BBTR was present in 44% of ATTR-CA patients, 8% of controls and 1% in HCM/AFD.

CONCLUSIONS

CTS and BBTR are fivefold more prevalent in ATTR-CA patients compared with cardiac patients with other hypertrophic phenotypes. Positive predictive accuracy for ATTR-CA is highest when involvement is bilateral. Upper limb assessment of patients with HCM phenotypes is a simple and effective way to raise suspicion of ATTR-CA.

Increased PARylation impacts the DNA methylation process in type 2 diabetes mellitus

Background

Epigenetic modifications, such as DNA methylation, can influence the genetic susceptibility to type 2 diabetes mellitus (T2DM) and the progression of the disease. Our previous studies demonstrated that the regulation of the DNA methylation pattern involves the poly(ADP-ribosyl)ation (PARylation) process, a post-translational modification of proteins catalysed by the poly(ADP-ribose) polymerase (PARP) enzymes. Experimental data showed that the hyperactivation of PARylation is associated with impaired glucose metabolism and the development of T2DM. Aims of this case–control study were to investigate the association between PARylation and global and site-specific DNA methylation in T2DM and to evaluate metabolic correlates.

Results

Data were collected from 61 subjects affected by T2DM and 48 healthy individuals, recruited as controls. Global levels of poly(ADP-ribose) (PAR, a surrogate of PARP activity), cytosine methylation (5-methylcytosine, 5mC) and de-methylation intermediates 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) were determined in peripheral blood cells by ELISA-based methodologies. Site-specific DNA methylation profiling of SOCS3, SREBF1 and TXNIP candidate genes was performed by mass spectrometry-based bisulfite sequencing, methyl-sensitive endonucleases digestion and by DNA immuno-precipitation. T2DM subjects presented higher PAR levels than controls. In T2DM individuals, increased PAR levels were significantly associated with higher HbA1c levels and the accumulation of the de-methylation intermediates 5hmC and 5fC in the genome. In addition, T2DM patients with higher PAR levels showed reduced methylation with increased 5hmC and 5fC levels in specific SOCS3 sites, up-regulated SOCS3 expression compared to both T2DM subjects with low PAR levels and controls.

Conclusions

This study demonstrates the activation of PARylation processes in patients with T2DM, particularly in those with poor glycaemic control. PARylation is linked to dysregulation of DNA methylation pattern via activation of the DNA de-methylation cascade and may be at the basis of the differential gene expression observed in presence of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01099-1.

Clisagri: An R package for agro-climate services

Crop yields are affected by unfavourable/extreme weather and climate events occurring during sensitive growth stages. Understanding the risks associated with these events is essential to adapt agro-management decisions and reduce losses. For this purpose, we propose a targeted climate service integrating a dynamic crop phenology model with an approach based on dedicated agro-climate risk indicators. The initial set of these indicators has been developed in a co-design approach with agronomists and durum wheat farmers participating as end-users in the H2020-MedGOLD project. Four groups of indicators characterize drought events, excessive wetness, cold stress and heat stress during sensitive growth stages. The proposed approach has been fully implemented as an R-package named Clisagri. The package is complemented with a set of optimization functions, which target optimal variety selection in terms of crop cycle duration.

Role of myocardial T1 mapping in arrhythmogenic right ventricular cardiomyopathy

Background

T1 mapping by cardiovascular magnetic resonance (CMR) is an accurate tool to assess myocardial extracellular space with wider clinical applications in the aetiological characterization of cardiomyopathies. The aims of the study were to explore a possible role of myocardial T1 mapping in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and in first-degree relatives at risk and to investigate the possible relationship between left ventricular (LV) involvement at CMR and ECG features.

Methods

Thirty patients with ARVC (47% males, mean age 42±22 years) and 59 first-degree relatives who did not fulfil ARVC diagnostic Task Force criteria, underwent full diagnostic work-up including CMR with native and post-contrast T1 mapping.

Results

The CMR was abnormal in 26 (86%) patients with ARVC. The RV was affected in isolation in 13 (43%) patients. Prior to T1 mapping assessment, 2 (7%) patients exhibited isolated LV involvement and 11 (36%) patients showed features of biventricular disease. Left ventricular involvement was manifested as detectable LV late gadolinium enhancement (LGE) in 12 out of 13 cases. According to pre-specified septal T1 mapping thresholds, 11 (37%) patients showed abnormally high native T1 values. Myocardial T1 mapping was higher than normal in 5 (17%) patients who would have been classified as exhibiting a normal LV by conventional imaging. The proportion of patients with abnormal T1 values was similar in patients with or without LGE. Myocardial T1 mapping was higher than normal in 22 (37%) of the 59 first-degree relatives.

Conclusions

Native and/or post contrast myocardial T1 values are raised in almost half of patients with ARVC and in a similar proportion of unaffected first-degree relatives. T1 mapping offers the potential for early detection of LV involvement in patients with ARVC and in first-degree relatives at risk.

Funding Acknowledgement

Type of funding source: None

Eosinophilic granulomatosis with polyangiitis, a new recurrent feature in an extremely rare disease

Introduction

Eosinophilic granulomatosis with polyangiitis (EGPA) is an extremely rare necrotizing vasculitis affecting small- and medium-sized vessels. EGPA may affect the heart leading to myocardial inflammation and necrosis. Although, only a few cardiological based studies have been conducted.

Purpose

This study aimed to investigate the prevalence and clinical impact of cardiac-specific involvement (CSI+) and to give an update on EGPA cardiological manifestations.

Methods

This is a single-centre study. Cardiological evaluation included ECG, blood test, echocardiography, global longitudinal strain (GLS), cardiac magnetic resonance (CMR).

Results

We prospectively enrolled 52 consecutive EGPA patients, between October 2018 and October 2019, mean age 59±3 years, 30 (57%) female. We identified 13 (25%) CSI+ patients: 6 myocarditis, 2 pericarditis, 1 coronaritis, 1 Prinzmetal angina, 2 LV apical thrombosis, 1 unexplained wall motions abnormalities (WMA) in the absence of coronary artery disease.

Twelve-leads ECG revealed abnormalities in 11 (85%) CSI+ vs 9 (23%) CSI−, p=0.0001; ECG abnormalities identified CSI+ with 85% sensitivity, 77% specificity, 94% negative predictive value.

Median troponin level in CSI+ 9 ng/L (IQR 6–11) vs CSI− 11 ng/L (IQR 6–25), p=0.2548; NT-pro-BNP value in CSI+ 210 pg/L (IQR 175–484) vs CSI− 159 ng/L (IQR 66–299), p=0.0576.

Echocardiographic left ventricular end diastolic volume in CSI+ 62±4 ml/m2 vs CSI− 52±1 ml/m2, p=0.0116; LV ejection fraction in CSI+ 57%±2 vs CSI− 66%±1, p=0.0002. In CSI+ patients GLS was −15±1 vs CSI− GLS −21±0.4, p&lt;0.0001. Echocardiography identified WMA in 8 (61%) CSI+ vs 1 (3%) CSI−. In 7 (54%) CSI+ patients, apical segments showed WMA and among them 5 demonstrated the presence of apical aneurysm.

Twelve patients underwent CMR, it showed non ischaemic late gadolinium enhancement in 7 patients; in 5 patients we identified akinetic or dyskinetic segments without associated LGE. Two patients showed LV apical thrombus.

Conclusions

EGPA showed a high prevalence of CSI. We repeatedly found a tropism for apical involvement in WMA that often manifested themselves as apical aneurysm. These may be a new clinical feature, previously not described, in such a rare condition.

Cardiac involvement EGPA

Funding Acknowledgement

Type of funding source: None

Molecules of Silence: Effects of Meditation on Gene Expression and Epigenetics

Many studies have consistently demonstrated an epigenetic link between environmental stimuli and physiological as well as cognitive responses. Epigenetic mechanisms represent a way to regulate gene activity in real time without modifying the DNA sequence, thus allowing the genome to adapt its functions to changing environmental contexts. Factors such as lifestyle, behavior, and the practice of sitting and moving mindful activities have been shown to be important means of environmental enrichment. Such practices, which include mindfulness meditation, Vipassana, Yoga, Tai Chi, and Quadrato Motor Training, have been reported to positively impact well-being. In fact, they can be considered emotional and attentional regulatory activities, which, by inducing a state of greater inner silence, allow the development of increased self-awareness. Inner silence can therefore be considered a powerful tool to counteract the negative effects of overabundant environmental noise, thanks to its power to relieve stress-related symptoms. Since all these positive outcomes rely on physiological and biochemical activities, the molecular and epigenetic mechanisms influenced by different mindful practices have recently started to be investigated. Here, we review some of the findings that could allow us to uncover the mechanisms by which specific practices influence well-being.

Paternal activation of CB2 cannabinoid receptor impairs placental and embryonic growth via an epigenetic mechanism

The cannabinoid receptor type 2 (CB₂) is the peripheral receptor for cannabinoids, involved in the homeostatic control of several physiological functions. Male mitotic germ cells express a high level of CB₂, whose activation promotes their differentiation in both in vitro and in vivo experiments, controlling the correct progression of spermatogenesis. However, it remains elusive if CB₂ activation in spermatogonia could affect reproductive success in terms of fertility and healthy pregnancy outcomes. In this study, we explored the effects of male CB₂ activation on sperm number and quality and its influence on next generation health. We show that exposure of male mice to JWH-133, a selective CB₂ agonist, decreased sperm count, impaired placental development and reduced offspring growth. These defects were associated with altered DNA methylation/hydroxymethylation levels at imprinted genes in sperm and conserved in placenta. Our findings reveal that paternal selective activation of CB₂ alters the sperm epigenome and compromises offspring growth. This study demonstrates, for the first time, a new role of CB₂ signaling in male gametes in causing epigenetic alterations that can be transmitted to the next generation by sperm, highlighting potential risks induced by recreational cannabinoid exposure.

Modifications of H3K4 methylation levels are associated with DNA hypermethylation in acute myeloid leukemia

The 'instructive model' of aberrant DNA methylation in human tumors is based on the observation that CpG islands prone to hypermethylation in cancers are embedded in chromatin enriched in H3K27me3 in human embryonic stem cells (hESC). Recent studies also link methylation of CpG islands to the methylation status of H3K4, where H3K4me3 is inversely correlated with DNA methylation. To provide insight into these conflicting findings, we generated DNA methylation profiles for acute myeloid leukemia samples from patients and leukemic cell lines and integrated them with publicly available ChIp-seq data, containing H3K4me3 and H3K27me3 CpG island occupation in hESC, or hematopoietic stem or progenitor cells (hHSC/MPP). Hypermethylated CpG islands in AML samples displayed H3K27me3 enrichments in hESC and hHSC/MPP; however, ChIp analysis of specific hypermethylated CpG islands revealed a significant reduction in H3K4me3 signal with a concomitant increase in H3K4me0 levels as opposed to a nonsignificant increase in H3K27me3 marks. The integration of AML DNA methylation profiles with the ChIp-seq data in hESC and hHSC/MPP also led to the identification of Iroquois homeobox 2 (IRX2) as a previously unknown factor promoting differentiation of leukemic cells. Our results indicate that in contrast to the 'instructive model', H3K4me3 levels are strongly associated with DNA methylation patterns in AML and have a role in the regulation of critical genes, such as the putative tumor suppressor IRX2.

Histone Modifications Drive Aberrant Notch3 Expression/Activity and Growth in T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood cancer caused by the deregulation of key T-cell developmental pathways, including Notch signaling. Aberrant Notch signaling in T-ALL occurs by NOTCH1 gain-of-function mutations and by NOTCH3 overexpression. Although NOTCH3 is assumed as a Notch1 target, machinery driving its transcription in T-ALL is undefined in leukemia subsets lacking Notch1 activation. Here, we found that the binding of the intracellular Notch3 domain, as well as of the activated Notch1 fragment, to the NOTCH3 gene locus led to the recruitment of the H3K27 modifiers JMJD3 and p300, and it was required to preserve transcriptional permissive/active H3K27 marks and to sustain NOTCH3 gene expression levels. Consistently, pharmacological inhibition of JMJD3 by GSKJ4 treatment or of p300 by A-485 decreased the levels of expression of NOTCH3, NOTCH1 and of the Notch target genes DELTEX1 and c-Myc and abrogated cell viability in both Notch1- and Notch3-dependent T-cell contexts. Notably, re-introduction of exogenous Notch1, Notch3 as well as c-Myc partially rescued cells from anti-growth effects induced by either treatment. Overall our findings indicate JMJD3 and p300 as general Notch1 and Notch3 signaling co-activators in T-ALL and suggest further investigation on the potential therapeutic anti-leukemic efficacy of their enzymatic inhibition in Notch/c-Myc axis-related cancers and diseases.

Using reanalysis in crop monitoring and forecasting systems

Weather observations are essential for crop monitoring and forecasting but they are not always available and in some cases they have limited spatial representativeness. Thus, reanalyses represent an alternative source of information to be explored. In this study, we assess the feasibility of reanalysis-based crop monitoring and forecasting by using the system developed and maintained by the European Commission- Joint Research Centre, its gridded daily meteorological observations, the biased-corrected reanalysis AgMERRA and the ERA-Interim reanalysis. We focus on Europe and on two crops, wheat and maize, in the period 1980-2010 under potential and water-limited conditions. In terms of inter-annual yield correlation at the country scale, the reanalysis-driven systems show a very good performance for both wheat and maize (with correlation values higher than 0.6 in almost all EU28 countries) when compared to the observations-driven system. However, significant yield biases affect both crops. All simulations show similar correlations with respect to the FAO reported yield time series. These findings support the integration of reanalyses in current crop monitoring and forecasting systems and point to the emerging opportunities linked to the coming availability of higher-resolution reanalysis updated at near real time.

DNA Hydroxymethylation Levels Are Altered in Blood Cells From Down Syndrome Persons Enrolled in the MARK-AGE Project

Down syndrome (DS) is caused by the presence of part or an entire extra copy of chromosome 21, a phenomenon that can cause a wide spectrum of clinically defined phenotypes of the disease. Most of the clinical signs of DS are typical of the aging process including dysregulation of immune system. Beyond the causative genetic defect, DS persons display epigenetic alterations, particularly aberrant DNA methylation patterns that can contribute to the heterogeneity of the disease. In the present work, we investigated the levels of 5-hydroxymethylcytosine and of the Ten-eleven translocation dioxygenase enzymes, which are involved in DNA demethylation processes and are often deregulated in pathological conditions as well as in aging. Analyses were carried out on peripheral blood mononuclear cells of DS volunteers enrolled in the context of the MARK-AGE study, a large-scale cross-sectional population study with subjects representing the general population in eight European countries. We observed a decrease in 5-hydroxymethylcytosine, TET1, and other components of the DNA methylation/demethylation machinery in DS subjects, indicating that aberrant DNA methylation patterns in DS, which may have consequences on the transcriptional status of immune cells, may be due to a global disturbance of methylation control in DS.

Analysis of the machinery and intermediates of the 5hmC-mediated DNA demethylation pathway in aging on samples from the MARK-AGE Study

Gradual changes in the DNA methylation landscape occur throughout aging virtually in all human tissues. A widespread reduction of 5-methylcytosine (5mC), associated with highly reproducible site-specific hypermethylation, characterizes the genome in aging. Therefore, an equilibrium seems to exist between general and directional deregulating events concerning DNA methylation controllers, which may underpin the age-related epigenetic changes. In this context, 5mC-hydroxylases (TET enzymes) are new potential players. In fact, TETs catalyze the stepwise oxidation of 5mC to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC), driving the DNA demethylation process based on thymine DNA glycosylase (TDG)-mediated DNA repair pathway. The present paper reports the expression of DNA hydroxymethylation components, the levels of 5hmC and of its derivatives in peripheral blood mononuclear cells of age-stratified donors recruited in several European countries in the context of the EU Project 'MARK-AGE'. The results provide evidence for an age-related decline of TET1, TET3 and TDG gene expression along with a decrease of 5hmC and an accumulation of 5caC. These associations were independent of confounding variables, including recruitment center, gender and leukocyte composition. The observed impairment of 5hmC-mediated DNA demethylation pathway in blood cells may lead to aberrant transcriptional programs in the elderly.

Diagnosis of sphingolipidoses: a new simultaneous measurement of lysosphingolipids by LC-MS/MS

Background:

Lysosphingolipids (LysoSLs) are derivatives of sphingolipids which have lost the amide-linked acyl chain. More recently, LysoSLs have been identified as storage compounds in several sphingolipidoses, including Gaucher, Fabry and Niemann-Pick diseases. To date, different methods have been developed to measure each individual lysosphingolipid in plasma. This report describes a rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) assay for simultaneous quantification of several LysoSLs in plasma.

Methods:

We analyzed the following compounds: hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM) and lysosphingomyelin-509 (LysoSM-509). The sample preparation requires only 100 μL of plasma and consists of an extraction with a mixture of MeOH/acetone/H

Results:

The method validation showed high sensitivity, an excellent accuracy and precision. Reference ranges were determined in healthy adult and pediatric population. The results demonstrate that the LC-MS/MS method can quantify different LysoSLs and can be used to identify patients with Fabry (LysoGb3), Gaucher and Krabbe (HexSph) diseases, prosaposine deficiency (LysoGb3 and HexSph), and Niemann-Pick disease types A/B and C (LysoSM and LysoSM-509).

Conclusions:

This LC-MS/MS method allows a rapid and simultaneous quantification of LysoSLs and is useful as a biochemical diagnostic tool for sphingolipidoses.

PARP1 orchestrates epigenetic events setting up chromatin domains

Epigenetic events include reversible modifications of DNA and histone tails driving chromatin organization and thus transcription. The epigenetic regulation is a highly integrated process underlying the plasticity of the genomic information both in the context of complex physiological and pathological processes. The global regulatory aspects of epigenetic events are largely unknown. PARylation and PARP1 are recently emerging as multi-level regulatory effectors that modulate the topology of chromatin by orchestrating very different processes. This review focuses in particular on the role of PARP1 in epigenetics, trying to build a comprehensive perspective of its involvement in the regulation of epigenetic modifications of histones and DNA, contextualizing it in the global organization of chromatin domains in the nucleus.

5mC-hydroxylase activity is influenced by the PARylation of TET1 enzyme

5-hydroxymethylcytosine is a new epigenetic modification deriving from the oxidation of 5-methylcytosine by the TET hydroxylase enzymes. DNA hydroxymethylation drives DNA demethylation events and is involved in the control of gene expression. Deregulation of TET enzymes causes developmental defects and is associated with pathological conditions such as cancer. Little information thus far is available on the regulation of TET activity by post-translational modifications. Here we show that TET1 protein is able to interact with PARP-1/ARTD1 enzyme and is target of both noncovalent and covalent PARylation. In particular, we have demonstrated that the noncovalent binding of ADP-ribose polymers with TET1 catalytic domain decreases TET1 hydroxylase activity while the covalent PARylation stimulates TET1 enzyme. In addition, TET1 activates PARP-1/ARTD1 independently of DNA breaks. Collectively, our results highlight a complex interplay between PARylation and TET1 which may be helpful in coordinating the multiple biological roles played by 5-hydroxymethylcytosine and TET proteins.

Age-dependent expression of DNMT1 and DNMT3B in PBMCs from a large European population enrolled in the MARK-AGE study

Aging is associated with alterations in the content and patterns of DNA methylation virtually throughout the entire human lifespan. Reasons for these variations are not well understood. However, several lines of evidence suggest that the epigenetic instability in aging may be traced back to the alteration of the expression of DNA methyltransferases. Here, the association of the expression of DNA methyltransferases DNMT1 and DNMT3B with age has been analysed in the context of the MARK-AGE study, a large-scale cross-sectional study of the European general population. Using peripheral blood mononuclear cells, we assessed the variation of DNMT1 and DNMT3B gene expression in more than two thousand age-stratified women and men (35-75 years) recruited across eight European countries. Significant age-related changes were detected for both transcripts. The level of DNMT1 gradually dropped with aging but this was only observed up to the age of 64 years. By contrast, the expression of DNMT3B decreased linearly with increasing age and this association was particularly evident in females. We next attempted to trace the age-related changes of both transcripts to the influence of different variables that have an impact on changes of their expression in the population, including demographics, dietary and health habits, and clinical parameters. Our results indicate that age affects the expression of DNMT1 and DNMT3B as an almost independent variable in respect of all other variables evaluated.

Scaling like behaviour of resistivity observed in LaNiO₃ thin films grown on SrTiO₃ substrate by pulsed laser deposition

We discuss the origin of the temperature dependence of resistivity ρ observed in highly oriented LaNiO3 thin films grown on SrTiO3 substrate by a pulsed laser deposition technique. All the experimental data are found to collapse into a single universal curve ρ(T, d) ∝ [T/T(sf)(d)]3/2 for the entire temperature interval (20K<T<300 K) with T(sf)(d) being the onset temperature for triggering a resonant scattering of conduction electrons by spin fluctuations in LaNiO3/SrTiO3 heterostructure.

Poly(ADP-ribosyl)ation is involved in the epigenetic control of TET1 gene transcription

TET enzymes are the epigenetic factors involved in the formation of the sixth DNA base 5-hydroxymethylcytosine, whose deregulation has been associated with tumorigenesis. In particular, TET1 acts as tumor suppressor preventing cell proliferation and tumor metastasis and it has frequently been found down-regulated in cancer. Thus, considering the importance of a tight control of TET1 expression, the epigenetic mechanisms involved in the transcriptional regulation of TET1 gene are here investigated. The involvement of poly(ADP-ribosyl)ation in the control of DNA and histone methylation on TET1 gene was examined. PARP activity is able to positively regulate TET1 expression maintaining a permissive chromatin state characterized by DNA hypomethylation of TET1 CpG island as well as high levels of H3K4 trimethylation. These epigenetic modifications were affected by PAR depletion causing TET1 down-regulation and in turn reduced recruitment of TET1 protein on HOXA9 target gene. In conclusion, this work shows that PARP activity is a transcriptional regulator of TET1 gene through the control of epigenetic events and it suggests that deregulation of these mechanisms could account for TET1 repression in cancer.

Reconfiguration of DNA methylation in aging

A complex interplay between multiple biological effects shapes the aging process. The advent of genome-wide quantitative approaches in the epigenetic field has highlighted the effective impact of epigenetic deregulation, particularly of DNA methylation, on aging. Age-associated alterations in DNA methylation are commonly grouped in the phenomenon known as "epigenetic drift" which is characterized by gradual extensive demethylation of genome and hypermethylation of a number of promoter-associated CpG islands. Surprisingly, specific DNA regions show directional epigenetic changes in aged individuals suggesting the importance of these events for the aging process. However, the epigenetic information obtained until now in aging needs a re-consideration due to the recent discovery of 5-hydroxymethylcytosine, a new DNA epigenetic mark present on genome. A recapitulation of the factors involved in the regulation of DNA methylation and the changes occurring in aging will be described in this review also considering the data available on 5 hmC.

The epigenetic factor BORIS/CTCFL regulates the NOTCH3 gene expression in cancer cells

Aberrant upregulation of NOTCH3 gene plays a critical role in cancer pathogenesis. However, the underlying mechanisms are still unknown. We tested here the hypothesis that aberrant epigenetic modifications in the NOTCH3 promoter region might account for its upregulation in cancer cells. We compared DNA and histone methylation status of NOTCH3 promoter region in human normal blood cells and T cell acute lymphoblastic leukemia (T-ALL) cell lines, differentially expressing NOTCH3. We found that histone methylation, rather than DNA hypomethylation, contributes towards establishing an active chromatin status of NOTCH3 promoter in NOTCH3 overexpressing cancer cells. We discovered that the chromatin regulator protein BORIS/CTCFL plays an important role in regulating NOTCH3 gene expression. We observed that BORIS is present in T-ALL cell lines as well as in cell lines derived from several solid tumors overexpressing NOTCH3. Moreover, BORIS targets NOTCH3 promoter in cancer cells and it is able to induce and to maintain a permissive/active chromatin conformation. Importantly, the association between NOTCH3 overexpression and BORIS presence was confirmed in primary T-ALL samples from patients at the onset of the disease. Overall, our results provide novel insights into the determinants of NOTCH3 overexpression in cancer cells, by revealing a key role for BORIS as the main mediator of transcriptional deregulation of NOTCH3.

TET2 gene expression and 5-hydroxymethylcytosine level in multiple sclerosis peripheral blood cells

Aberrant DNA methylation can lead to genome destabilization and to deregulated gene expression. Recently, 5-hydroxymethylcytosine (5hmC), derived from oxidation of 5-methylcytosine (5mC) by the Ten-Eleven Translocation (TET) enzymes, has been detected. 5hmC is now considered as a new epigenetic DNA modification with relevant roles in cell homeostasis regulating DNA demethylation and transcription. Our aim was to investigate possible changes in the DNA methylation/demethylation machinery in MS. We assessed the expression of enzymes involved in DNA methylation/demethylation in peripheral blood mononuclear cells (PBMCs) from 40 subjects with MS and 40 matched healthy controls. We performed also, DNA methylation analysis of specific promoters and analysis of global levels of 5mC and 5hmC. We show that TET2 and DNMT1 expression is significantly down-regulated in MS PBMCs and it is associated with aberrant methylation of their promoters. Furthermore, 5hmC is decreased in MS PBMCs, probably as a result of the diminished TET2 level.

Poly(ADP-ribosyl)ation acts in the DNA demethylation of mouse primordial germ cells also with DNA damage-independent roles

Poly(ADP-ribosyl)ation regulates chromatin structure and transcription driving epigenetic events. In particular, Parp1 is able to directly influence DNA methylation patterns controlling transcription and activity of Dnmt1. Here, we show that ADP-ribose polymer levels and Parp1 expression are noticeably high in mouse primordial germ cells (PGCs) when the bulk of DNA demethylation occurs during germline epigenetic reprogramming in the embryo. Notably, Parp1 activity is stimulated in PGCs even before its participation in the DNA damage response associated with active DNA demethylation. We demonstrate that PARP inhibition impairs both genome-wide and locus-specific DNA methylation erasure in PGCs. Moreover, we evidence that impairment of PARP activity causes a significant reduction of expression of the gene coding for Tet1 hydroxylases involved in active DNA demethylation. Taken together these results demonstrate new and adjuvant roles of poly(ADP-ribosyl)ation during germline DNA demethylation and suggest its possible more general involvement in genome reprogramming.

Adaptation as a genome-wide autoregulatory principle in the stress response of yeast

The gene expression response of yeast to various types of stresses/perturbations shows a common functional and dynamical pattern for the vast majority of genes, characterised by a quick transient peak (affecting primarily short genes) followed by a return to the pre-stimulus level. Kinetically, this process of adaptation following the transient excursion can be modelled using a genome-wide autoregulatory mechanism by means of which yeast aims at maintaining a preferential concentration in its mRNA levels. The resulting feedback system explains well the different time constants observable in the transient response, while being in agreement with all the known experimental dynamical features. For example, it suggests that a very rapid transient can be induced also by a slowly varying concentration of the gene products.

Methylation-dependent PAD2 upregulation in multiple sclerosis peripheral blood

BACKGROUND

Peptidylarginine deiminase 2 (PAD2) and peptidylarginine deiminase 4 (PAD4) are two members of PAD family which are over-expressed in the multiple sclerosis (MS) brain. Through its enzymatic activity PAD2 converts myelin basic protein (MBP) arginines into citrullines - an event that may favour autoimmunity - while peptidylarginine deiminase 4 (PAD4) is involved in chromatin remodelling.

OBJECTIVES

Our aim was to verify whether an altered epigenetic control of PAD2, as already shown in the MS brain, can be observed in peripheral blood mononuclear cells (PBMCs) of patients with MS since some of these cells also synthesize MBP.

METHODS

The expression of most suitable reference genes and of PAD2 and PAD4 was assessed by qPCR. Analysis of DNA methylation was performed by bisulfite method.

RESULTS

The comparison of PAD2 expression level in PBMCs from patients with MS vs. healthy donors showed that, as well as in the white matter of MS patients, the enzyme is significantly upregulated in affected subjects. Methylation pattern analysis of a CpG island located in the PAD2 promoter showed that over-expression is associated with promoter demethylation.

CONCLUSION

Defective regulation of PAD2 in the periphery, without the immunological shelter of the blood-brain barrier, may contribute to the development of the autoimmune responses in MS.

Low doses of 3-aminobenzamide, a poly(ADP-ribose) polymerase inhibitor, stimulate angiogenesis by regulating expression of urokinase type plasminogen activator and matrix metalloprotease 2

Background

Poly(ADP-Ribose) polymerase (PARP) activity has been demonstrated fundamental in many cellular processes, including DNA repair, cell proliferation and differentiation. In particular, PARP activity has been recently found to affect proliferation, migration, and tube formation of human umbilical vein endothelial cells. In recent times, PARP inhibitors have entered in clinical trials to potentiate cancer treatments by preventing DNA repair, but little is known about the effects performed by different drug concentrations on neoangiogenesis, an essential step in tumor growth.

Methods

Human umbilical vein endothelial cells were treated with 3 aminobenzamide (3ABA), a PARP inhibitor, and tested for several different cellular parameters.

Results

Here we present in vitro evidence that a low concentration of 3ABA (50 μM), stimulates angiogenesis by decreasing fibrinolytic activity, carried out by urokinase-type plasminogen activator (uPA), and by enhancing matrix metalloprotease-2 (MMP-2) gelatinolytic activity, in fibroblast growth factor-2-stimulated endothelial cells. These unbalanced pathways modify in vitro angiogenic steps, inhibiting chemoinvasion and stimulating tubulogenic activity.

Conclusions

Our results suggest that the proangiogenic effect of low concentrations of 3ABA alerts on the efficacy of PARP inhibitors to potentiate anticancer therapy. Moreover, they indicate that endothelial chemoinvasion and tubulogenesis depend on distinct proteolytic pathways.

Poly(ADP-ribosyl)ation affects stabilization of Che-1 protein in response to DNA damage

Poly(ADP-ribose) polymerase 1 (PARP-1) catalyzes a post-translational modification that plays a crucial role in coordinating the signalling cascade in response to stress stimuli. During the DNA damage response, phosphorylation by ataxia telangiectasia mutated (ATM) kinase and checkpoint kinase Chk2 induces the stabilization of Che-1 protein, which is critical for the maintenance of G2/M arrest. In this study we showed that poly(ADP-ribosyl)ation, beyond phosphorylation, is involved in the regulation of Che-1 stabilization following DNA damage. We demonstrated that Che-1 accumulation upon doxorubicin treatment is reduced after the inhibition of PARP activity in HCT116 cells and in PARP-1 knock-out or silenced cells. In accordance, impairment in Che-1 accumulation by PARP inhibition reduced Che-1 occupancy at p21 promoter and affected the expression of the corresponding gene. Epistasis experiments showed that the effect of poly(ADP-ribosyl)ation on Che-1 stabilization is independent from ATM kinase activity. Indeed we demonstrated that Che-1 protein co-immunoprecipitates with ADP-ribose polymers and that PARP-1 directly interacts with Che-1, promoting its modification in vitro and in vivo.

Validation of suitable internal control genes for expression studies in aging

Quantitative data from experiments of gene expression are often normalized through levels of housekeeping genes transcription by assuming that expression of these genes is highly uniform. This practice is being questioned as it becomes increasingly clear that the level of housekeeping genes expression may vary considerably in certain biological samples. To date, the validation of reference genes in aging has received little attention and suitable reference genes have not yet been defined. Our aim was to evaluate the expression stability of frequently used reference genes in human peripheral blood mononuclear cells with respect to aging. Using quantitative RT-PCR, we carried out an extensive evaluation of five housekeeping genes, i.e. 18s rRNA, ACTB, GAPDH, HPRT1 and GUSB, for stability of expression in samples from donors in the age range 35-74 years. The consistency in the expression stability was quantified on the basis of the coefficient of variation and two algorithms termed geNorm and NormFinder. Our results indicated GUSB be the most suitable transcript and 18s the least for accurate normalization in PBMCs. We also demonstrated that aging is a confounding factor with respect to stability of 18s, HPRT1 and ACTB expression, which were particularly prone to variability in aged donors.

Inhibition of PARP activity by PJ-34 leads to growth impairment and cell death associated with aberrant mitotic pattern and nucleolar actin accumulation in M14 melanoma cell line

The capability of PARP activity inhibitors to prevent DNA damage recovery suggested the use of these drugs as chemo- and radio-sensitisers for cancer therapy. Our research, carried out on cultured human M14 melanoma cells, was aimed to examine if PJ-34, a potent PARP activity inhibitor of second generation, was per se able to affect the viability of these cancer cells without any DNA damaging agents. Using time-lapse videomicroscopy, we evidenced that 10 microM PJ-34 treatment induced severe mitotic defects leading to dramatic reduction of cell proliferation and to cell death. PJ-34 cytotoxic effect was further confirmed by analysis of cell viability and clonogenic assay. Absence of canonic apoptosis markers allowed us to exclude this kind of cell death. No single and/or double stranded DNA damage was evidenced. Immunofluorescence analysis showed an aberrant mitotic scenario in several cells and subsequent multinucleation suggesting an atypical way for cells to die: the mitotic catastrophe. The detection of aberrant accumulation of polymerised actin inside the nucleolus was noteworthy. Taken together, our results demonstrate that, targeting PARP activity by PJ-34, cancer cell survival is affected independently of DNA damage repair. Two findings are remarkable: (a) cisplatin concentration can be reduced by three quarters if it is followed by treatment with 10 microM PJ-34 for 24 h to obtain the same cytotoxic effect; (b) effects dependent on PJ-34 treatment are reversible. Our data suggest that, to reduce the harm done to non-tumour cells during chemotherapy with cisplatin, the latter could be coupled with PJ-34 treatment.

Parp1 localizes within the Dnmt1 promoter and protects its unmethylated state by its enzymatic activity

Background

Aberrant hypermethylation of CpG islands in housekeeping gene promoters and widespread genome hypomethylation are typical events occurring in cancer cells. The molecular mechanisms behind these cancer-related changes in DNA methylation patterns are not well understood. Two questions are particularly important: (i) how are CpG islands protected from methylation in normal cells, and how is this protection compromised in cancer cells, and (ii) how does the genome-wide demethylation in cancer cells occur. The latter question is especially intriguing since so far no DNA demethylase enzyme has been found.

Methodology/Principal Findings

Our data show that the absence of ADP-ribose polymers (PARs), caused by ectopic over-expression of poly(ADP-ribose) glycohydrolase (PARG) in L929 mouse fibroblast cells leads to aberrant methylation of the CpG island in the promoter of the Dnmt1 gene, which in turn shuts down its transcription. The transcriptional silencing of Dnmt1 may be responsible for the widespread passive hypomethylation of genomic DNA which we detect on the example of pericentromeric repeat sequences. Chromatin immunoprecipitation results show that in normal cells the Dnmt1 promoter is occupied by poly(ADP-ribosyl)ated Parp1, suggesting that PARylated Parp1 plays a role in protecting the promoter from methylation.

Conclusions/Significance

In conclusion, the genome methylation pattern following PARG over-expression mirrors the pattern characteristic of cancer cells, supporting our idea that the right balance between Parp/Parg activities maintains the DNA methylation patterns in normal cells. The finding that in normal cells Parp1 and ADP-ribose polymers localize on the Dnmt1 promoter raises the possibility that PARylated Parp1 marks those sequences in the genome that must remain unmethylated and protects them from methylation, thus playing a role in the epigenetic regulation of gene expression.

CCCTC-binding factor activates PARP-1 affecting DNA methylation machinery

Our previous data have shown that in L929 mouse fibroblasts the control of methylation pattern depends in part on poly(ADP-ribosyl)ation and that ADP-ribose polymers (PARs), both present on poly(ADP-ribosyl)ated PARP-1 and/or protein-free, have an inhibitory effect on Dnmt1 activity. Here we show that transient ectopic overexpression of CCCTC-binding factor (CTCF) induces PAR accumulation, PARP-1, and CTCF poly(ADP-ribosyl)ation in the same mouse fibroblasts. The persistence in time of a high PAR level affects the DNA methylation machinery; the DNA methyltransferase activity is inhibited with consequences for the methylation state of genome, which becomes diffusely hypomethylated affecting centromeric minor satellite and B1 DNA repeats. In vitro data show that CTCF is able to activate PARP-1 automodification even in the absence of nicked DNA. Our new finding that CTCF is able per se to activate PARP-1 automodification in vitro is of great interest as so far a burst of poly(ADP-ribosyl)ated PARP-1 has generally been found following introduction of DNA strand breaks. CTCF is unable to inhibit DNMT1 activity, whereas poly(ADP-ribosyl)ated PARP-1 plays this inhibitory role. These data suggest that CTCF is involved in the cross-talk between poly(ADP-ribosyl)ation and DNA methylation and underscore the importance of a rapid reversal of PARP activity, as DNA methylation pattern is responsible for an important epigenetic code.

Oxidative DNA damage repair and parp 1 and parp 2 expression in Epstein-Barr virus-immortalized B lymphocyte cells from young subjects, old subjects, and centenarians

Oxidative DNA damage has been implicated in the aging process and in some of its features such as telomere shortening and replicative senescence. Poly(ADP-ribosyl)ation is involved in many molecular and cellular processes, including DNA damage detection and repair, chromatin modification, transcription, and cell death pathways. We decided to examine the behavior of poly(ADP-ribosyl)ation in centenarians, i.e., those subjects who represent the best example of longevity having reached a very advanced age avoiding the main age-associated diseases. In this study we investigated the relationship between DNA repair capacity and poly(ADP-ribose) polymerase activity in Epstein-Barr virus-immortalized B lymphocyte cell lines from subjects of three different groups of age, including centenarians. Our data show that cells from centenarians have characteristics typical of cells from young people both in their capability of priming the mechanism of repair after H(2)O(2) sublethal oxidative damage and in poly(ADP-ribosyl)ation capacity, while in cells from old subjects these phenomena are delayed or decreased. Moreover, cells from old subjects show a constitutive expression level of both parp 1 and parp 2 genes reduced by a half, together with a reduced presence of modified PARP 1 and other poly(ADP-ribosyl)ated chromatin proteins in comparison to cells from young subjects and centenarians. Our data support the hypothesis that this epigenetic modification is an important regulator of the aging process in humans and it appears to be rather preserved in healthy centenarians, the best example of successful aging.

DNA methylation and chromatin structure: the puzzling CpG islands

DNA methylation is the epigenetic modification, which introduces 5mC as fifth base onto DNA. As for the distribution of 5mCs, it is well known that they distribute themselves in a non-random fashion in genomic DNA so that methylation pattern is characterized by the presence of methylated cytosines on the bulk of DNA while the unmethylated ones are mainly located within particular regions termed CpG islands. These regions represent about 1% of genomic DNA and are generally found in the promoter region of housekeeping genes. Their unmethylated state, which is an essential condition for the correct expression of correlated genes, is paradoxical if one considers that these regions are termed CpG islands because they are particularly rich in this dinucleotide, which is the best substrate for enzymes involved in DNA methylation. Anomalous insertion of methyl groups in these regions generally leads to the lack of transcription of correlated genes. An interesting scientific problem is to clarify the mechanism(s) whereby CpG islands, which remain protected from methylation in normal cells, are susceptible to methylation in tumor cells. How the CpG moieties in CpG islands become vulnerable or resistant to the action of DNA methyltransferases and can thus lose or maintain their characteristic pattern of methylation is still an open question. Our aim is to gather some mechanisms regarding this intriguing enigma, which, despite all energy spent, still remains an unresolved puzzle.

Modulation of DNMT1 activity by ADP-ribose polymers

We provided evidence that competitive inhibition of poly(ADP-ribose) polymerases in mammalian cells treated with 3-aminobenzamide causes DNA hypermethylation in the genome and anomalous hypermethylation of CpG islands. The molecular mechanism(s) connecting poly(ADP-ribosyl)ation with DNA methylation is still unknown. Here we show that DNMT1 is able to bind long and branched ADP-ribose polymers in a noncovalent way. Binding of poly ADP-ribose on DNMT1 inhibits DNA methyltransferase activity. Co-immunoprecipitation reactions indicate that PARP1 and DNMT1 are associated in vivo and that in this complex PARP1 is present in its ADP-ribosylated isoform. We suggest that this complex is catalytically inefficient in DNA methylation.