Developmental regulation of canonical and small ORF translation from mRNAs.

BACKGROUND: Ribosomal profiling has revealed the translation of thousands of sequences outside annotated protein-coding genes, including small open reading frames of less than 100 codons, and the translational regulation of many genes. Here we present an improved version of Poly-Ribo-Seq and apply it to Drosophila melanogaster embryos to extend the catalog of in vivo translated small ORFs, and to reveal the translational regulation of both small and canonical ORFs from mRNAs across embryogenesis. RESULTS: We obtain highly correlated samples across five embryonic stages, with nearly 500 million putative ribosomal footprints mapped to mRNAs, and compare them to existing Ribo-Seq and proteomic data. Our analysis reveals, for the first time in Drosophila, footprints mapping to codons in a phased pattern, the hallmark of productive translation. We propose a simple binomial probability metric to ascertain translation probability. Our results also reveal reproducible ribosomal binding apparently not resulting in productive translation. This non-productive ribosomal binding seems to be especially prevalent amongst upstream short ORFs located in the 5' mRNA leaders, and amongst canonical ORFs during the activation of the zygotic translatome at the maternal-to zygotic transition. CONCLUSIONS: We suggest that this non-productive ribosomal binding might be due to cis-regulatory ribosomal binding and to defective ribosomal scanning of ORFs outside periods of productive translation. Our results are compatible with the main function of upstream short ORFs being to buffer the translation of canonical canonical ORFs; and show that, in general, small ORFs in mRNAs display markers compatible with an evolutionary transitory state towards full coding function.

Does renal function improve after parathyroidectomy in primary hyperparathyroidism? / ¿Mejora la función renal tras la paratiroidectomía en el hiperparatirodismo primario?

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterised by hypercalcaemia and parathormone increase. Decreased glomerular filtration rate (<60ml/min) continues to be a parathyroidectomy (PTX) criterion in asymptomatic PHPT. The influence of PTX on renal function evolution is the subject of debate. OBJECTIVE: To analyse the clinical, laboratory and histological characteristics of patients undergoing PHPT, as well as renal function evolution after PTX. MATERIAL AND METHODS: Retrospective study of 297 patients diagnosed with PHPT and referred to surgery in a single centre between 1998 and 2016. Laboratory parameters were determined at baseline, one week and one year after PTX. RESULTS: The Incidence of PTX was 38 cases/million/year. Mean age was 60±14 years and 80.5% of the patients were female. Approximately 65.3% were asymptomatic. Nephrolithiasis was the most common clinical finding (33%), followed by bone involvement (29.5%). PTX indications were: clinical symptoms (34.7%), hypercalcaemia>11.2mg/dl (27%), nephrolithiasis (13%), low bone mass (12%), age<50 years (11%) and decreased glomerular filtration rate<60ml/min (2.3%). For diagnostic localisation, spect-MIBI had a sensitivity of 92% and cervical ultrasound of 70%. A total of 94.3% of PHPT cases were due to a parathyroid adenoma. After PTX, normalisation of PHPT-related parameters was observed. We found a significant increase in serum creatinine levels (0.81 vs 0.85mg/dl, P<.001) from the first week post-PTX until the end of the first year. The renal function was only found to be significant in patients with glomerular filtration rate>60ml/min (baseline serum creatinine levels 0.77mg/dl vs serum creatinine levels after one year 0.81mg/dl, P<.001). CONCLUSIONS: PHPT was asymptomatic in most patients who underwent surgery. Hypercalcaemia and nephrolithiasis were the most common indications of parathyroidectomy in asymptomatic patients. MIBI scan was the most useful localisation method. Surgical treatment of PHPT is followed by renal function impairment, which persists after the first week post-PTX.

Trabecular bone score and bone mineral density in patients with postsurgical hypoparathyroidism after total thyroidectomy for differentiated thyroid carcinoma.

BACKGROUND: Although bone mineral density is reported to be increased in patients with postsurgical hypoparathyroidism (postsurgical HypoPT), the effect of HypoPT on trabecular bone score remains unknown. This study evaluated the long-term effects of HypoPT secondary to total thyroidectomy for differentiated thyroid cancer on trabecular bone score, bone mineral density, and bone turnover markers with a similar group of patients without HypoPT. METHODS: Women with resected differentiated thyroid cancer and either postsurgical HypoPT (n = 25; 8 premenopausal and 17 postmenopausal) or euparathyroid function (n = 98; 14 premenopausal and 84 postmenopausal) were matched for age and body mass index. Patients received thyroid-stimulating hormone suppression during follow-up. The bone mineral density and trabecular bone score were analyzed using dual x-ray densitometry and Med-Imaps software at baseline (1-3 months postsurgery) and at the final study visit. RESULTS: Follow-up duration was similar in studied groups (median 10 years). Baseline bone mineral density and trabecular bone score were similar between HypoPT and non-HypoPT patients, regardless of menopausal status. At study end, postmenopausal HypoPT patients had greater bone mineral density versus the non-HypoPT patients at the lumbar spine, hip, and distal radius (P = .001), and a greater trabecular bone score (1.31 ± 0.09 vs 1.24 ± 0.12, P = .0184). Premenopausal patients with and without HypoPT had similar bone mineral density values at the final evaluation. The bone turnover markers (osteocalcin, bone-specific alkaline phosphatase, and ß-crosslaps) were less in postmenopausal HypoPT patients, reflecting decreased bone turnover. CONCLUSION: Postmenopausal patients who underwent a total thyroidectomy for differentiated thyroid cancer with postsurgical HypoPT have greater trabecular bone score and bone mineral density compared with euparathyroid patients, suggesting that HypoPT protects against the negative effects of long-term thyroid-stimulating hormone suppression treatment on bone.

Low trabecular bone score in postmenopausal women with differentiated thyroid carcinoma after long-term TSH suppressive therapy.

The effect of thyroid suppression therapy (TST) on trabecular bone scores (TBS) and bone mineral density (BMD) in thyroidectomized women with differentiated thyroid carcinoma (DTC) on long-term follow-up is presently not conclusive. PATIENTS AND METHODS: We carried out a study in 61 premenopausal and 84 postmenopausal Caucasian women with DTC. Serum biochemistry, bone markers, TBS, BMD, and bone fractures were evaluated 1-3 months post surgery and after a median follow-up of 10 years. RESULTS: In the final study, patients belonged to Group I Premenopausal (n = 14) who remained in this status; Group II Premenopausal who became postmenopausal (n = 47); Group III patients who were and continued as postmenopausal (n = 84). Baseline premenopausal patients had a normal TBS mean value of 1.39 ± 0.14 significantly higher than that found in postmenopausal 1.31 ± 0.12 (p = 001). In the final study, premenopausal patients continued to have a normal TBS of 1.46 ± 0.08 compared to the significantly lower value of postmenopausal patients 1.25 ± 0.11 (p = 0.0009). Lumbar BMD (L-BMD) loss after the long-term study was significant in Group II (0.99 g/cm2 ± 0.13 vs. 0.91 ± 0.12 g/cm2, p < 0.0001) and there was a slight, but not significant, bone loss in Group I (1.00 ± 0.12 vs. 0.98 ± 0.11, p = 0.1936) and in Group III (0.86 ± 0.12 vs. 0.84 ± 0.15, p = 0.1924) compared with baseline values. CONCLUSION: Longer-term suppression therapy in female patients with DTC did not increase significantly the risk of bone loss, although we found in postmenopausal patients deterioration of bone microarchitecture. TBS study should be considered in the evaluation of postmenopausal DTC patients on long-term DTC for the evaluation of the risk of fractures.

Functions of long non-coding RNAs in human disease and their conservation in Drosophila development.

Genomic analysis has found that the transcriptome in both humans and Drosophila melanogaster features large numbers of long non-coding RNA transcripts (lncRNAs). This recently discovered class of RNAs regulates gene expression in diverse ways and has been involved in a large variety of important biological functions. Importantly, an increasing number of lncRNAs have also been associated with a range of human diseases, including cancer. Comparative analyses of their functions among these organisms suggest that some of their modes of action appear to be conserved. This highlights the importance of model organisms such as Drosophila, which shares many gene regulatory networks with humans, in understanding lncRNA function and its possible impact in human health. This review discusses some known functions and mechanisms of action of lncRNAs and their implication in human diseases, together with their functional conservation and relevance in Drosophila development.

[Intrathyroidal location of parathyroid glands. Atypical presentation of multiple endocrine neoplasia type 1 syndrome]. / Localización intratiroidea de glándulas paratiroides. Presentación atípica del síndrome de neoplasia endocrina múltiple tipo 1.

BACKGROUND: The most common manifestation of MEN 1 syndrome is primary hyperparathyroidism (PHPT) with parathyroid multiglandular affectation. The intrathyroidal situation represents 3-4% of all glands, and it is the second most frequent location in the cervical ectopias. CLINICAL CASE: 11 year old patient, with a family history of MEN1 syndrome and carrier of this same mutation. Patient presents HPTP with osteopenia. The cervical ultrasound shows three compatible images with pathological parathyroid glands (bilateral lower and upper left). The Scan and MRI are normal. Bone densitometry displays data on osteopenia. The patient is surgically intervened, only the upper parathyroid glands are located and removed, after this implantation is performed on the forearm, to prevent the possible devascularization in the dissection of the other glands. However, osteopenia persists and an elevated PTH, therefore new diagnostic tests are held which seem to show two lower parathyroid glands with intrathyroidal location. The patient is reoperated. A subtotal parathyroidectomy of the lower right gland and the resection of the left gland is performed, with the use of intraoperative ultrasound and placement of harpoon. The intraoperative pathology study confirms parathyroid tissue in both cases. DISCUSSION: It is necessary to locate the parathyroid glands preoperatively in order to alert us of the existence of topographical and ectopia abnormalities, as well as their intrathyroidal location (0.5-3.6%). CONCLUSION: The intraoperative ultrasound can be a complement to the experience of the endocrine surgeon for the localization of the parathyroid glands and therefore can help determine the best surgical strategy for each clinical case.

Conserved regulation of cardiac calcium uptake by peptides encoded in small open reading frames.

Small open reading frames (smORFs) are short DNA sequences that are able to encode small peptides of less than 100 amino acids. Study of these elements has been neglected despite thousands existing in our genomes. We and others previously showed that peptides as short as 11 amino acids are translated and provide essential functions during insect development. Here, we describe two peptides of less than 30 amino acids regulating calcium transport, and hence influencing regular muscle contraction, in the Drosophila heart. These peptides seem conserved for more than 550 million years in a range of species from flies to humans, in which they have been implicated in cardiac pathologies. Such conservation suggests that the mechanisms for heart regulation are ancient and that smORFs may be a fundamental genome component that should be studied systematically.

Interplay between a Wnt-dependent organiser and the Notch segmentation clock regulates posterior development in Periplaneta americana.

Sequential addition of segments in the posteriorly growing end of the embryo is a developmental mechanism common to many bilaterians. However, posterior growth and patterning in most animals also entails the establishment of a 'posterior organiser' that expresses the Caudal and Wnt proteins and has been proposed to be an ancestral feature of animal development. We have studied the functional relationships between the Wnt-driven organiser and the segmentation mechanisms in a basal insect, the cockroach Periplaneta americana. Here, posteriorly-expressed Wnt1 promotes caudal and Delta expression early in development to generate a growth zone from which segments will later bud off. caudal maintains the undifferentiated growth zone by dampening Delta expression, and hence Notch-mediated segmentation occurs just outside the caudal domain. In turn, Delta expression maintains Wnt1, maintaining this posterior gene network until all segments have formed. This feedback between caudal, Wnt and Notch-signalling in regulating growth and segmentation seems conserved in other arthropods, with some aspects found even in vertebrates. Thus our findings not only support an ancestral Wnt posterior organiser, but also impinge on the proposals for a common origin of segmentation in arthropods, annelids and vertebrates.

The 11-aminoacid long Tarsal-less peptides trigger a cell signal in Drosophila leg development.

The polycistronic and non-canonical gene tarsal-less encodes several short peptides 11 to 32 aminoacids long. tarsal-less is required for embryonic and imaginal development in Drosophila, but the molecular and cellular bases of its function are not known. Here we show that tarsal-less function triggers a cell signal. This signal has a range of 2-3 cells in Drosophila legs and may be provided directly by the Tarsal-less peptides. During leg development, this Tarsal-less signal implements the patterning activity of a tarsal boundary and regulates the transcription of several genes in a specific manner. Thus tarsal-less is necessary for the intercalation of the tarsal segments two to four and for the activation of the homeobox gene apterous, the Zinc-finger gene rotund and the bHLH-PAS gene spineless, and for the repression of the homeobox gene Bar and the putative transcription factor dacshund. These regulatory effects complement the known genetic scenario required for distal leg development and explain the requirements for tarsal-less in this process.

Peptides encoded by short ORFs control development and define a new eukaryotic gene family.

Despite recent advances in developmental biology, and the sequencing and annotation of genomes, key questions regarding the organisation of cells into embryos remain. One possibility is that uncharacterised genes having nonstandard coding arrangements and functions could provide some of the answers. Here we present the characterisation of tarsal-less (tal), a new type of noncanonical gene that had been previously classified as a putative noncoding RNA. We show that tal controls gene expression and tissue folding in Drosophila, thus acting as a link between patterning and morphogenesis. tal function is mediated by several 33-nucleotide-long open reading frames (ORFs), which are translated into 11-amino-acid-long peptides. These are the shortest functional ORFs described to date, and therefore tal defines two novel paradigms in eukaryotic coding genes: the existence of short, unprocessed peptides with key biological functions, and their arrangement in polycistronic messengers. Our discovery of tal-related short ORFs in other species defines an ancient and noncanonical gene family in metazoans that represents a new class of eukaryotic genes. Our results open a new avenue for the annotation and functional analysis of genes and sequenced genomes, in which thousands of short ORFs are still uncharacterised.

Parallels between the proximal-distal development of vertebrate and arthropod appendages: homology without an ancestor?

Evolutionary studies suggest that the limbs of vertebrates and the appendages of arthropods do not share a common origin. However, recent genetic studies show new similarities in their developmental programmes. These similarities might be caused by the independent recruitment of homologous genes for similar functions or by the conservation of an ancestral proximal-distal development programme. This basic programme might have arisen in an ancestral outgrowth and been independently co-opted in vertebrate and arthropod appendages. It has subsequently diverged in both phyla to fine-pattern the limb and to control phylum-specific cellular events. We suggest that although vertebrate limbs and arthropod appendages are not strictly homologous structures they retain remnants of a common ancestral developmental programme.

Chip-mediated partnerships of the homeodomain proteins Bar and Aristaless with the LIM-HOM proteins Apterous and Lim1 regulate distal leg development.

Proximodistal patterning in Drosophila requires division of the developing leg into increasingly smaller, discrete domains of gene function. The LIM-HOM transcription factors apterous (ap) and Lim1 (also known as dlim1), and the homeobox genes Bar and aristaless (al) are part of the gene battery required for the development of specific leg segments. Our genetic results show that there are posttranslational interactions between Ap, Bar and the LIM-domain binding protein Chip in tarsus four, and between Al, Lim1 and Chip in the pretarsus, and that these interactions depend on the presence of balanced amounts of such proteins. We also observe in vitro protein binding between Bar and Chip, Bar and Ap, Lim1 and Chip, and Al and Chip. Together with the previous evidence for interactions between Ap and Chip, these results suggest that these transcription factors form protein complexes during leg development. We propose that the different developmental outcomes of LIM-HOM function are due to the precise identity and dosage of the interacting partners present in a given cell.