ATP13A2/PARK9 regulates endo-/lysosomal cargo sorting and proteostasis through a novel PI(3, 5)P2-mediated scaffolding function.

ATP13A2 (also called PARK9), is a transmembrane endo-/lysosomal-associated P5 type transport ATPase. Loss-of-function mutations in ATP13A2 result in the Kufor-Rakeb Syndrome (KRS), a form of autosomal Parkinson's disease (PD). In spite of a growing interest in ATP13A2, very little is known about its physiological role in stressed cells. Recent studies suggest that the N-terminal domain of ATP13A2 may hold key regulatory functions, but their nature remains incompletely understood. To this end, we generated a set of melanoma and neuroblastoma cell lines stably overexpressing wild-type (WT), catalytically inactive (D508N) and N-terminal mutants, or shRNA against ATP13A2. We found that under proteotoxic stress conditions, evoked by the proteasome inhibitor Bortezomib, endo-/lysosomal associated full-length ATP13A2 WT, catalytically-inactive or N-terminal fragment mutants, reduced the intracellular accumulation of ubiquitin-conjugated (Ub) proteins, independent of autophagic degradation. In contrast, ATP13A2 silencing increased the intracellular accumulation of Ub-proteins, a pattern also observed in patient-derived fibroblasts harbouring ATP13A2 loss-of function mutations. In treated cells, ATP13A2 evoked endocytic vesicle relocation and increased cargo export through nanovesicles. Expression of an ATP13A2 mutant abrogating PI(3,5)P2 binding or chemical inhibition of the PI(3,5)P2-generating enzyme PIKfyve, compromised vesicular trafficking/nanovesicles export and rescued intracellular accumulation of Ub-proteins in response to proteasomal inhibition. Hence, our study unravels a novel activity-independent scaffolding role of ATP13A2 in trafficking/export of intracellular cargo in response to proteotoxic stress.

Concurrent MEK and autophagy inhibition is required to restore cell death associated danger-signalling in Vemurafenib-resistant melanoma cells.

Vemurafenib (PLX4032), an inhibitor of BRAF(V600E), has demonstrated significant clinical anti-melanoma effects. However, the majority of treated patients develop resistance, due to a variety of molecular mechanisms including MAPK reactivation through MEK. The induction of a cancer cell death modality associated with danger-signalling resulting in surface mobilization of crucial damage-associated-molecular-patterns (DAMPs), e.g. calreticulin (CRT) and heat shock protein-90 (HSP90), from dying cells, is emerging to be crucial for therapeutic success. Both cell death and danger-signalling are modulated by autophagy, a key adaptation mechanism stimulated during melanoma progression. However, whether melanoma cell death induced by MAPK inhibition is associated with danger-signalling, and the reliance of these mechanisms on autophagy, has not yet been scrutinized. Using a panel of isogenic PLX4032-sensitive and resistant melanoma cell lines we show that PLX4032-induced caspase-dependent cell death and DAMPs exposure in the drug-sensitive cells, but failed to do so in the drug-resistant cells, displaying heightened MEK activation. MEK inhibitor, U0126, treatment sensitized PLX4032-resistant cells to death and re-established their danger-signalling capacity. Only melanoma cells exposing death-induced danger-signals were phagocytosed and induced DC maturation. Although the PLX4032-resistant melanoma cells displayed higher basal and drug-induced autophagy, compromising autophagy, pharmacologically or by ATG5 knockdown, was insufficient to re-establish their PLX4032 sensitivity. Interestingly, autophagy abrogation was particularly efficacious in boosting cell death and ecto-CRT/ecto-HSP90 in PLX4032-resistant cells upon blockage of MEK hyper-activation by U0126. Thus combination of MEK inhibitors with autophagy blockers may represent a novel treatment regime to increase both cell death and danger-signalling in Vemurafenib-resistant metastatic melanoma.

Cardiac side effects of long-acting beta-2 agonist salmeterol in asthmatic children.

BACKGROUND: Salmeterol is a new long-acting beta 2 selective adrenoreceptor agonist. There are some reports about the cardiac side-effects of salmeterol in asthmatic adults. The aim of this study was to determine the cardiac side effects of salmeterol in children. METHODS: Seventeen children with moderate asthma (aged between 6 and 13 years, mean 8.76 years) received salmeterol with a spacer device (Volumatic 200 micrograms daily, b.i.d.) for 3 weeks. All the children were evaluated by 24 h ambulatory electrocardiography monitoring and echocardiography before, on the second and on the 21st day of treatment. RESULTS: In minimum heart rate measurements, there were significant differences between the baseline (mean +/- SD 54.29 +/- 7.13), second (59.24 +/- 6.86) and 21st day (60.65 +/- 8.23) results. Also, the mean heart rate before the treatment (89.59 +/- 6.78) was significantly different from that on the second (94.76 +/- 6.51) and 21st day (92.65 +/- 8.90) of treatment. Although all the values were within normal limits and there were no significant differences between the control group's values, a trend of increase in mean and the minimum heart rates was seen. There were no significant differences in blood pressure, serum K+, maximum heart rate, supraventricular and ventricular ectopic beats, ejection fraction, stroke volume, cardiac output and corrected QT interval at any time. No complaints of tremors or palpitations were reported. CONCLUSIONS: As no cardiac side effects were detected, it could be concluded that salmeterol is quite a safe drug for use in childhood asthma treatment.

The effect of different doses of epidermal growth factor on liver ornithine decarboxylase and Na-K ATPase activities in newborn rats.

1. Ornithine decarboxylase and Na-K ATPase activities were studied in rat livers that were treated with different doses of epidermal growth factor (EGF). 2. The ornithine decarboxylase activities were studied with spectrophotometry, and results were expressed as micromoles of putrescine per hour per milligram of protein. Na-K ATPase activities were studied on the basis of the principle of measuring the amount of inorganic phosphates released by the hydrolysis of ATP, and the results were expressed as micromoles of inorganic phosphate per hour per milligram of protein. 3. When compared with the controls, although the Na-K ATPase activities were decreased at low doses of EGF, their activities were found to be increased at high doses of EGF. On the other hand, there was a positive correlation between ornithine decarboxylase activities and EGF doses. 4. The results of this study suggest that, whereas the decrease in Na-K ATPase activities at low doses of EGF can be due to the utilization of the enzyme, the increase in Na-K ATPase activities at high doses of EGF can be attributed to its enhanced synthesis.

The association of chronic urticaria and angioedema with autoimmune thyroiditis.

BACKGROUND: An increased frequency of autoimmune thyroiditis is seen in patients with chronic urticaria and angioedema (CUA) and it has been hypothesized that autoimmunity may be playing a role in the pathogenesis of CUA. The aim of this study was to learn the extent of autoimmune thyroid disease in a series of patients who presented with CUA. METHODS: Thyroid function tests and thyroid autoantibodies were measured by radioimmunoassay and immunoradiometric assay respectively in 94 CUA patients and 80 age- and sex-matched healthy volunteers. RESULTS: Eleven patients (11.7%) were found to have thyroglobulin antibodies (TGA) and nine patients (9.57%) thyroid microsomal (TMA) titers ranging from 150 to 1340.37 and from 165.73 to 8000 IU/mL respectively. Both antibodies were detected in three control cases (3.7%). The association was statistically significant (P < 0.01). Six of 11 patients had thyroid dysfunction and the other five cases were euthyroid. CONCLUSIONS: Our results justified the use of TMA and TGA for the early diagnosis of autoimmune thyroiditis in combination with CUA. The higher frequency of these antibodies in our patients, along with results from previously published data, suggest that this entity may reflect an autoimmune basis in some CUA patients. Thyroid function tests are not enough to rule out thyroid disease, and thyroid antibody tests should be carried out in all patients with CUA.

Effects of inhaled steroid treatment on serum eosinophilic cationic protein (ECP) and low affinity receptor for IgE (Fc epsilon RII/sCD23) in childhood bronchial asthma.

Serum eosinophilic cationic protein (ECP) and soluble low affinity receptor for IgE (Fc epsilon RII/sCD23) concentrations were measured in relation to symptom-medication scores, pulmonary function, and total IgE levels in 27 chronic allergic asthmatic children (17 boys, 10 girls), mean age 10.8 years, before and at the end of a three month inhaled corticosteroid (budesonide) treatment period. Serum ECP and sCD23 concentrations were also measured in age matched non-asthmatic controls with allergic rhinitis. All asthma patients had significantly higher serum ECP and sCD23 than the controls, whereas the mean serum IgE was not different. No correlation between total IgE concentrations and serum sCD23 could be detected in either group. At the end of the treatment period, symptom-medication scores and pulmonary function improved. Serum ECP and sCD23 concentrations were reduced; however, total IgE values did not change significantly. A significant relation was found between the improvement of symptom-medication scores and fall in both sCD23 and ECP concentrations. Although there was a significant correlation of pulmonary function values with serum ECP, no such relation was observed for sCD23. It appears that serum sCD23 and ECP concentrations could be good disease markers, particularly in asthma. Monitoring of serum inflammation markers, especially ECP, may be useful in the follow up of asthmatic children on anti-inflammatory treatment.

Chest pain in children referred to a cardiology clinic.

One hundred consecutive patients (54 girls, 46 boys) referred to a pediatric cardiology department with the primary complaint of chest pain were evaluated. The age distribution was 2.5-16.0 years (mean 11.3 years for girls and 9.9 years for boys). The history showed 17% of patients with chest pain, 22% with heart disease, and 19% with recent death in the family. The time course of the pain was longer than 1 week in 92 patients. Localization was on the left precordium in 60 patients, and there was no radiation from the original site in 66 cases. Ninety-two percent of cases were idiopathic in origin. Of the 74 patients who had a psychiatric interview, 55 (74%) had psychiatric symptoms and 5 required psychiatric care. Anxiety, conversion disorder, and depression were the main psychiatric symptoms.

Hungry bone syndrome in a child following parathyroid surgery.

The rare hungry bone syndrome was encountered in a 15-year-old child after the removal of a parathyroid adenoma. Contrary to the hypocalcemias caused by the removal of all parathyroid glands or transient ischemia after parathyroid surgery, in which the serum inorganic phosphorus level is usually normal, both serum calcium and inorganic phosphorus levels are decreased in hungry bone syndrome in the early postoperative period. Vigorous calcium supplementation and vitamin D are required for prolonged periods.

Unusual variation of asplenia syndrome.

The case of a 1-year-old cyanotic boy diagnosed with asplenia syndrome has been reported. By physical and laboratory examinations, levocardia, atrial inversion, primum ASD, single atrioventricular valve, single ventricle (left-hand morphology), rudimentary right ventricle (anterior, left-sided), pulmonary stenosis, left-sided vena cava, single vena cava superior were established and the case was diagnosed with asplenia syndrome. The patient has concordance between tracheo-bronchial situs and lung anatomy and inverted atrial and visceral situs, but without atrial isomerism that makes his case an unusual variation of asplenia syndrome.

The effect of epidermal growth factor on serum zinc levels.

Epidermal growth factor is a potent stimulator of the growth of epithelial and mesenchymal cells. In this study the effect of epidermal growth factor on the cells of developing mice intestine and on the serum zinc concentrations were assessed. Higher serum zinc concentrations (840.21 +/- 187.82 mg/dl) were found in the mice given epidermal growth factor (n: 10) as compared to the values obtained in the controls (347.55 +/- 108.88 mg/dl), (n: 12) (p less than 0.05).

A case of mucopolysaccharidoses type I with heart involvement during infancy.

We report a case of mucopolysaccharidoses I with severe cardiac involvement, which was diagnosed on the basis of clinical and laboratory findings even though, symptoms begin to occur in mucopolysaccharidoses after the first year of life. In our case cardiac failure occurred in the third month of life, which resulted in the patient's death after one month.