Role of PML in telomere metabolism of normal and cancer cells

Telomeres are specialized structures that cap chromosomes ends, protecting them from degradation and processing by the DNA-repair machinery. In normal cells, telomeres become progressively shorter during replication, and this leads to replicative senescence. The majority of human tumors (approximately 90%) express the ribonucleic complex telomerase, that prevents this continuous DNA loss, thus endowing cells with immortal growth properties. In the remaining 10% of tumors telomerase is not expressed, and telomeric DNA is preserved through alternative mechanisms (Alternative Lengthening of Telomeres, ALT). An hallmark of all ALT tumor cell lines is the presence of nuclear structures that localize exclusively at telomeres (ALT-associated PML nuclear bodies, APBs). Here we show that PML (ProMyelocitic Leukemia protein), a nuclear protein that is an essential component of PML nuclear bodies (PML-NBs), colocalizes with telomeres not only in telomerase-positive tumor cell lines, but also in normal cells, although at few telomeres. Interestingly, in normal cells telomere-specific DNA-damage induced recruitment of PML to damaged telomeres. Furthermore, PML depletion led to the formation of Telomere Dysfunction-Induced Foci (TIFs) and consequent growth inhibition in normal and ALT cell lines. Preliminary cytogenetic characterization of PML-depleted fibroblasts revealed diffused genomic defects, suggesting that PML is a key regulator of telomere maintenance and whole genomic stability. Unpublished data from our lab have shown that DNA-PKcs, an enzyme involved in DNA repair and telomere stability, is part of the PML-macromolecular protein complex. To investigate the mechanism involvement of PML activity in telomere maintenance we studied by confocal microscopy its interaction with the active phosporylated form of DNA-PKcs in ALT cell lines and in normal cells. As expected, not only the two proteins interacted at telomeres, but PML was essential for the correct localization of DNA-PKcs at the chromosome ends. Additionally, telomeric-specific damage in normal cells increased the interaction between DNA-PKcs and PML. Altogether these findings shed light on a Telomeres are specialized structures that cap chromosomes ends, protecting them from degradation and processing by the DNA-repair machinery. In normal cells, telomeres become progressively shorter during replication, and this leads to replicative senescence. The majority of human tumors (approximately 90%) express the ribonucleic complex telomerase, that prevents this continuous DNA loss, thus endowing cells with immortal growth properties. In the remaining 10% of tumors telomerase is not expressed, and telomeric DNA is preserved through alternative mechanisms (Alternative Lengthening of Telomeres, ALT). An hallmark of all ALT tumor cell lines is the presence of nuclear structures that localize exclusively at telomeres (ALT-associated PML nuclear bodies, APBs). Here we show that PML (ProMyelocitic Leukemia protein), a nuclear protein that is an essential component of PML nuclear bodies (PML-NBs), colocalizes with telomeres not only in telomerase-positive tumor cell lines, but also in normal cells, although at few telomeres. Interestingly, in normal cells telomere-specific DNA-damage induced recruitment of PML to damaged telomeres. Furthermore, PML depletion led to the formation of Telomere Dysfunction-Induced Foci (TIFs) and consequent growth inhibition in normal and ALT cell lines. Preliminary cytogenetic characterization of PML-depleted fibroblasts revealed diffused genomic defects, suggesting that PML is a key regulator of telomere maintenance and whole genomic stability. Unpublished data from our lab have shown that DNA-PKcs, an enzyme involved in DNA repair and telomere stability, is part of the PML-macromolecular protein complex. To investigate the mechanism involvement of PML activity in telomere maintenance we studied by confocal microscopy its interaction with the active phosporylated form of DNA-PKcs in ALT cell lines and in normal cells. As expected, not only the two proteins interacted at telomeres, but PML was essential for the correct localization of DNA-PKcs at the chromosome ends. Additionally, telomeric-specific damage in normal cells increased the interaction between DNA-PKcs and PML. Altogether these findings shed light on a novel role for PML in the regulation of telomere metabolism, and are the basis for future investigations on its role in both aging and cancer

Adrenal pheochromocytoma incidentally discovered in a patient with parkinsonism

To evaluate the diagnostic route of pheochromocytoma (PHEO) in a patient under dopaminergic treatment. A 70-year-old man with Parkinsonism and under treatment with levodopa and carbidopa came to our observation for evaluation of arterial hypertension and right adrenal mass discovered incidentally. To evaluate adrenal hormone levels we performed a dexamethasone suppression test, plasma aldosterone levels and 24-hr urinary metanephrine, which revealed elevated levels of catecholamines metabolities. 123-I-metaiodobenzylguanidine SPECT scintiscan revealed raised activity within the right adrenal gland concordant with the mass. The diagnosis of PHEO was posed and an elective laparoscopic adrenalectomy was performed; histopathological examination confirmed the PHEO diagnosis. Recently the coexistence of PHEO and Parkinsonism is a very rare association of diseases, with only 3 cases reported in literature. In this article, another case is reported and diagnostic procedures are discusse

Resistant arterial hypertension in a patient with adrenal incidentaloma multiple steno-obstructive vascular lesions and antiphospholipid syndrome

Resistant hypertension is defined as above of blood pressure (≤ 140/90 mmHg) despite therapy with three or more antihypertensive drugs of different classes at maximum tolerable doses with one bling a diuretic. An important consideration in defining a patient with resistant hypertension is the mislabeling of secondary hypertension as resistant hypertension. Here, we report a patients with resistant hypertension caused by multiple stenoocclusive arteries due to antiphospholipid syndrome and coexisting with subclinical Cushing’s syndrome

Hypokalemic rhabdomyolysis: a rare manifestation of primary aldosteronism

Rhabdomyolysis is a rare presentation of hypokalemia, although muscle weakness is a well-known manifestation of hypokalemia. Primary aldosteronism is characterized by hypertension, suppressed plasma renin activity, increased aldosterone excretion and hypokalemia with metabolic alkalosis. Rhabdomyolysis is not common in primary aldosteronism. We present here a 40-year-old woman presenting with rhabdomyolysis accompanied by severe hypokalemia as heralding symptom of primary aldosteronism

DESIGN AND CONTROL OF AN ACTIVE HUMANOID LEG FOR TESTING LOWER-LIMB PROSTHESES

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Arterial Hypertension, Metabolic Syndrome and Subclinical Cardiovascular Organ Damage in Patients with Asymptomatic Primary Hyperparathyroidism before and after Parathyroidectomy: Preliminary Results

Background. Primary hyperparathyroidism (PHPT) is associated with high cardiovascular morbidity, and the role of calcium and parathyroid hormone is still controversial. Objective. To evaluate the prevalence and outcomes of metabolic syndrome, hypertension, and some cardiovascular alterations in asymptomatic PHPT, and specific changes after successful parathyroidectomy. Material and Methods. We examined 30 newly diagnosed PHPT patients (8 males, 22 females; mean age 56 ± 6 yrs), 30 patients with essential hypertension (EH) (9 males, 21 females; mean age 55 ± 4), and 30 normal subjects (NS) (9 males, 21 females: mean age 55 ± 6). All groups underwent evaluation with ambulatory monitoring blood pressure, echocardiography, and color-Doppler artery ultrasonography and were successively revaluated after one year from parathyroidectomy. Results. PHPT patients presented a higher prevalence of metabolic syndrome (38%) with respect to EH (28%). Prevalence of hypertension in PHPT was 81%, and 57% presented altered circadian rhythm of blood pressure, with respect to EH (35%) and NS (15%). PHPT showed an important myocardial and vascular remodelling. During follow-up in PHPT patients, we found significant reduction of prevalence of metabolic syndrome, blood pressure, and “non-dipping phenomenon.” Conclusions. Cardiovascular and metabolic alterations should be considered as added parameters in evaluation of patients with asymptomatic PHPT

The prevalence of resistant arterial hypertension and secondary causes in a cohort of hypertensive patients: a single center experience

The prevalence of resistant hypertension (RHT) still remains unknown. Aim of the study was to investigate in a large cohort of hypertensive patients the prevalence of RHT, and to identify in these patients the secondary forms of arterial hypertension (SH). We enrolled a series of 3685 consecutive hypertensive patients. All patients underwent complete physical examination, laboratory tests, screening for SH. Ambulatory blood pressure monitoring (ABPM) was performed to exclude white-coat hypertension. Further, we investigated for any obstructive sleep apnea syndrome (OSA). Only 232 (5.8%) hypertensive patients fulfilled criteria for RHT. 91 (39%) had a SH; 56 (61%) hypertensive patients had a primary aldosteronism, 22 (24%) had OSA, 7 (7.7%) had a hypercortisolism, and 5 (5.5%) had a renovascular hypertension (RVH). Only one patient had adrenal pheochromocytoma. An accurate definition and investigation into RHT is needed. We recommend ABPM to all patients at diagnosis. Finally, all patients must be screened for SH, such as adrenal hypertension, OSA and RVH, especially those who are apparently resistant to polypharmacological treatment

Brown Fat Expresses Adiponectin in Humans

The presence of brown adipose tissue (BAT) in humans is unclear. Pheochromocytomas (PHEO) are rare tumors of neuroectodermal origin which occur in 0.1-0.2% of patients with hypertension. We sought to evaluate the presence and activity of BAT surrounding adrenal PHEO in a well-studied sample of 11 patients who were diagnosed with PHEO and then underwent adrenalectomy. Areas of white fat (WAT) and BAT surrounding PHEO were obtained by Laser Capture Microdissection for analysis of uncoupling protein (UCP)-1 and adiponectin mRNA expression. Adiponectin and UCP-1 mRNA levels were significantly higher in BAT than in WAT (0.62 versus 0.15 and 362.4 versus 22.1, resp., for both). Adiponectin mRNA levels significantly correlated with urinary metanephrines (, ), vanilly mandelic acid (VMA) (, ), and serum adiponectin levels (, ). Serum adiponectin levels significantly decreased ( μg/mL versus  μg/mL, ) after adrenalectomy in PHEO subjects. This study provides the following findings: (1) BAT surrounding PHEO expresses adiponectin and UCP-1 mRNA, (2) expression of adiponectin mRNA is significantly higher in BAT than in WAT surrounding PHEO, and (3) catecholamines and serum adiponectin levels significantly correlate with BAT UCP-1 and adiponectin mRNA

Event reconstruction for KM3NeT/ORCA using convolutional neural networks

The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino detector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower- or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches