Sorting Signals, N-Terminal Modifications and Abundance of the Chloroplast Proteome

Characterization of the chloroplast proteome is needed to understand the essential contribution of the chloroplast to plant growth and development. Here we present a large scale analysis by nanoLC-Q-TOF and nanoLC-LTQ-Orbitrap mass spectrometry (MS) of ten independent chloroplast preparations from Arabidopsis thaliana which unambiguously identified 1325 proteins. Novel proteins include various kinases and putative nucleotide binding proteins. Based on repeated and independent MS based protein identifications requiring multiple matched peptide sequences, as well as literature, 916 nuclear-encoded proteins were assigned with high confidence to the plastid, of which 86% had a predicted chloroplast transit peptide (cTP). The protein abundance of soluble stromal proteins was calculated from normalized spectral counts from LTQ-Obitrap analysis and was found to cover four orders of magnitude. Comparison to gel-based quantification demonstrates that ‘spectral counting’ can provide large scale protein quantification for Arabidopsis. This quantitative information was used to determine possible biases for protein targeting prediction by TargetP and also to understand the significance of protein contaminants. The abundance data for 550 stromal proteins was used to understand abundance of metabolic pathways and chloroplast processes. We highlight the abundance of 48 stromal proteins involved in post-translational proteome homeostasis (including aminopeptidases, proteases, deformylases, chaperones, protein sorting components) and discuss the biological implications. N-terminal modifications were identified for a subset of nuclear- and chloroplast-encoded proteins and a novel N-terminal acetylation motif was discovered. Analysis of cTPs and their cleavage sites of Arabidopsis chloroplast proteins, as well as their predicted rice homologues, identified new species-dependent features, which will facilitate improved subcellular localization prediction. No evidence was found for suggested targeting via the secretory system. This study provides the most comprehensive chloroplast proteome analysis to date and an expanded Plant Proteome Database (PPDB) in which all MS data are projected on identified gene models

Clinical impact of Pancreatic metastases from renal cell carcinoma : A multicenter retrospective analysis

Pancreatic metastases from renal cell carcinoma are uncommon and their prognostic significance is not well defined. In this analysis we evaluated the outcome of patients with pancreatic metastases treated with either targeted therapies or local treatment to the pancreas. Patients with pancreatic metastases from renal cell carcinoma treated between 1993 and 2014 were identified from 11 European centers. Clinical records were retrospectively reviewed. Kaplan-Meier method and log-rank test were used to evaluate progression-free survival and overall survival. Cox's proportional hazard models were used for survival analysis. In total, 276 PM patients were evaluated, including 77 (28%) patients treated by either surgery or radiotherapy to the pancreas, and 256 (93%) who received systemic therapy. Median time from nephrectomy to diagnosis of pancreatic metastases was 91 months (IQR 54-142). Disease control rate after first-line TTs was 84%, with a median progression-free survival of 12 months (95% CI 10-14). Median overall survival was 73 months (95% CI 61-86) with a 5-year OS of 58%. Median OS of patients treated with local treatment was 106 months (95% CI 78-204) with a 5-year overall survival of 75%. On multivariable analysis, nephrectomy (HR 5.31; 95%CI 2.36-11.92; p<0.0001), Memorial Sloan Kettering/International Metastatic RCC Database Consortium prognostic score (HR 1.45, 95% CI 0.94-2.23 for intermediate vs good vs risk; HR 2.76 95%, CI 1.43-5.35 for poor vs good risk p = 0.0099) and pancreatic local treatment (HR 0.48; 95%CI 0.30-0.78 p = 0.0029) were associated with overall survival. Difference in median OS between patients with PM and that reported in a matched-control group of mRCC patients with extrapancreatic metastases was statistically significant (p <.0001). Pancreatic metastases from renal cell carcinoma usually occur years after nephrectomy, are associated with an indolent behavior and a prolonged survival. Targeted therapies and locoregional approaches are active and achieve high disease control rate

NatF Contributes to an Evolutionary Shift in Protein N-Terminal Acetylation and Is Important for Normal Chromosome Segregation

N-terminal acetylation (N-Ac) is a highly abundant eukaryotic protein modification. Proteomics revealed a significant increase in the occurrence of N-Ac from lower to higher eukaryotes, but evidence explaining the underlying molecular mechanism(s) is currently lacking. We first analysed protein N-termini and their acetylation degrees, suggesting that evolution of substrates is not a major cause for the evolutionary shift in N-Ac. Further, we investigated the presence of putative N-terminal acetyltransferases (NATs) in higher eukaryotes. The purified recombinant human and Drosophila homologues of a novel NAT candidate was subjected to in vitro peptide library acetylation assays. This provided evidence for its NAT activity targeting Met-Lys- and other Met-starting protein N-termini, and the enzyme was termed Naa60p and its activity NatF. Its in vivo activity was investigated by ectopically expressing human Naa60p in yeast followed by N-terminal COFRADIC analyses. hNaa60p acetylated distinct Met-starting yeast protein N-termini and increased general acetylation levels, thereby altering yeast in vivo acetylation patterns towards those of higher eukaryotes. Further, its activity in human cells was verified by overexpression and knockdown of hNAA60 followed by N-terminal COFRADIC. NatF's cellular impact was demonstrated in Drosophila cells where NAA60 knockdown induced chromosomal segregation defects. In summary, our study revealed a novel major protein modifier contributing to the evolution of N-Ac, redundancy among NATs, and an essential regulator of normal chromosome segregation. With the characterization of NatF, the co-translational N-Ac machinery appears complete since all the major substrate groups in eukaryotes are accounted for

Craniopharyngioma in children: importance of a multidisciplinary approach and therapeutic strategies in the treatment of relapsing.

The craniopharyngioma is a benign intracranial nonglial tumor derived from a malformation of the embryonic tissue. Represents approximately 6-9% of brain tumors in children. It grows close to the optic nerve, hypothalamus and pituitary. The most frequent histological variety in children is adamantinomatous. The initial symptoms of intracranial hypertension is headache and nausea, followed by visual disturbances, impaired hormonal changes such as the secretion of GH, gonadotropins, TSH and ACTH and central diabetes insipidus. We present the clinical case of MD, 5yrs at age, which shows signs of intracranial hypertension syndrome: neuroradiological findings raise the diagnosis of adamantinomatous craniopharyngioma for which the child underwent to sub-total surgical removal of the lesion and radiosurgery treatment. During the disease develops visual impairment, and secondary diabetes insipidus, hypothyroidism hipocotisolism that takes therapy with desmopressin (Minirin), Cortone acetate and L-tiroxine. For the failure of previous therapies, the child has performed chemotherapy with cisplatin (30 mg/sqm/day) and Etoposide (150 mg/mq/day). A year after the end of the last cycle of chemotherapy was detected new progression of the lesion with the appearance of worsening headache and vomiting in the upright position. TC notes the expansion of the third ventricle and the patient undergoes surgery craniotomy. This clinical case underlines the difficulties in treatment of recurrent craniopharyngioma in situations where the anatomical location do not permit aggressive radical surgery. Anyway, new studies are needed to evaluate the effectiveness of systemic chemotherapy as a method of experimental treatment that could reduce the progression of disease

Vitamin D Deficiency and Glycemic Status in Children and Adolescents with Type 1 Diabetes Mellitus.

BACKGROUND: Vitamin D (25OHD) effects on glycemic control are unclear in children and adolescents with type 1 diabetes. Aims of this study were to investigate 25OHD status among children with T1DM and its relationship with insulin sensitivity and glycemic status. SUBJECTS AND METHODS: A cross sectional study was carried out between 2008-2014. A total of 141 patients had a T1DM >12 months diagnosis and were enrolled in the present study. Of these 35 (24.8%) were migrants and 106 (75.2%) Italians (T2). We retrospectively analyzed data at the onset of the disease (T0)(64 subjects) and 12-24 months before the last visit (T1,124 subjects). Fasting glucose, glycated hemoglobin (HbA1c), 25OHD levels and daily insulin requirement were evaluated and Cholecalciferol 1000 IU/day supplementation for the management of vitamin D insufficiency (<75 nmol/L) was systematically added. RESULTS: A generalized 25OHD insufficiency was found at each study time, particularly in migrants. At T0, the 25OHD levels were inversely related to diabetic keto-acidosis (DKA) severity (p8%), both at T1 and T2. In supplemented subjects, we found a significant increase in 25OHD levels (p<0.0001) and decrease of HbA1c (p<0.001) between T1 and T2, but this was not significant in the migrants subgroup. Multivariate regression analysis showed a link between HbA1c and 25OHD levels (p<0.001). CONCLUSIONS: Children with T1DM show a generalized 25OHD deficiency that impact on metabolic status and glycemic homeostasis. Vitamin D supplementation improves glycemic control and should be considered as an additional therapy

Linear growth and puberty in childhood obesity: what is new?

Pediatric obesity is a growing and alarming global health problem and represents an important determinant of morbidity. Since nutrition plays an important role in regulating growth and development, the excess weight gain related to overnutrition can affect growth patterns, bone maturation and pubertal development. The purpose of this review is to summarize the current knowledge about the effect of primary obesity on linear growth and pubertal development in children and adolescents. Evidences about regulatory hormones and adipokines that may be involved in the physiology of childhood growth in the context of obesity were also discussed. The most recent literature confirms previous studies indicating that linear growth is accelerated (mainly due to longer trunks rather than longer legs) and bone age is advanced in prepubertal children with obesity, while there is a reduction of pubertal height gain and attainment of normal adult height. Conflicting results are reported on the timing of puberty, specifically in boys. Indeed, previous studies suggested earlier onset of puberty in obese girls and overweight boys, and a delayed puberty in obese boys. Conversely, the most recent studies show more consistently an earlier onset and completion of pubertal development also in boys with obesity. Considering the false belief of health associated with transient taller stature in children and the adverse outcomes related to early puberty, interventions on diet and physical activity are urgently needed to tackle the epidemics of childhood obesity in public health and clinical setting