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Thyroid : Official Journal of the... Feb 2023Congenital hypothyroidism due to defects in iodotyrosine deiodinase has variable phenotypes and can present as hypothyroid or with normal thyroid testing. Whole exome...
Congenital hypothyroidism due to defects in iodotyrosine deiodinase has variable phenotypes and can present as hypothyroid or with normal thyroid testing. Whole exome sequencing was performed in individuals from two families originating from different regions of Sudan. Mass spectrometry of urine and serum iodotyrosines was performed on subjects from both families. A novel iodotyrosine deiodinase (IYD) mutation (c.835C>T; R279C) was identified in individuals from two Sudanese families inherited as autosomal recessive. The mutation was identified by multiple in silica analyses to likely be detrimental. Serum and urine monoiodotyrosine (MIT) and diiodotyrosine (DIT) were markedly elevated in the homozygous subjects. Measurement of serum and urine DIT and MIT was more sensitive than that of urine iodine or serum thyroid function tests to determine the effect of the IYD mutation.
Topics: Humans; Congenital Hypothyroidism; Diiodotyrosine; Iodide Peroxidase; Monoiodotyrosine; Mutation
PubMed: 36633921
DOI: 10.1089/thy.2022.0492 -
Acta Crystallographica. Section D,... Nov 2021Thyroglobulin is a homodimeric glycoprotein that is essential for the generation of thyroid hormones in vertebrates. Upon secretion into the lumen of follicles in the...
Thyroglobulin is a homodimeric glycoprotein that is essential for the generation of thyroid hormones in vertebrates. Upon secretion into the lumen of follicles in the thyroid gland, tyrosine residues within the protein become iodinated to produce monoiodotyrosine (MIT) and diiodotyrosine (DIT). A subset of evolutionarily conserved pairs of DIT (and MIT) residues can then engage in oxidative coupling reactions that yield either thyroxine (T; produced from coupling of a DIT `acceptor' with a DIT `donor') or triiodothyronine (T; produced from coupling of a DIT acceptor with an MIT donor). Although multiple iodotyrosine residues have been identified as potential donors and acceptors, the specificity and structural context of the pairings (i.e. which donor is paired with which acceptor) have remained unclear. Here, single-particle cryogenic electron microscopy (cryoEM) was used to generate a high-resolution reconstruction of bovine thyroglobulin (2.3 Å resolution in the core region and 2.6 Å overall), allowing the structural characterization of two post-reaction acceptor-donor pairs as well as tyrosine residues modified as MIT and DIT. A substantial spatial separation between donor Tyr149 and acceptor Tyr24 was observed, suggesting that for thyroxine synthesis significant peptide motion is required for coupling at the evolutionarily conserved thyroglobulin amino-terminus.
Topics: Animals; Cattle; Cryoelectron Microscopy; Halogenation; Protein Conformation; Protein Domains; Protein Multimerization; Thyroglobulin
PubMed: 34726172
DOI: 10.1107/S2059798321010056 -
Acta Naturae 2021Early (preclinical) diagnosis of Parkinson's disease (PD) is a major challenge in modern neuroscience. The objective of this study was to experimentally evaluate a...
Early (preclinical) diagnosis of Parkinson's disease (PD) is a major challenge in modern neuroscience. The objective of this study was to experimentally evaluate a diagnostic challenge test with monoiodotyrosine (MIT), an endogenous inhibitor of tyrosine hydroxylase. Striatal dopamine was shown to decrease by 34% 2 h after subcutaneous injection of 100 mg/kg MIT to intact mice, with the effect not being amplified by a further increase in the MIT dose. The selected MIT dose caused motor impairment in a neurotoxic mouse model of preclinical PD, but not in the controls. This was because MIT reduced striatal dopamine to the threshold of motor symptoms manifestation only in PD mice. Therefore, using the experimental mouse model of preclinical PD, we have shown that a MIT challenge test may be used to detect latent nigrostriatal dysfunction.
PubMed: 34707902
DOI: 10.32607/actanaturae.11399 -
Biology Open Jun 2021Across the animal kingdom, dopamine plays a crucial role in conferring reinforcement signals that teach animals about the causal structure of the world. In the fruit fly...
Across the animal kingdom, dopamine plays a crucial role in conferring reinforcement signals that teach animals about the causal structure of the world. In the fruit fly Drosophila melanogaster, dopaminergic reinforcement has largely been studied using genetics, whereas pharmacological approaches have received less attention. Here, we apply the dopamine-synthesis inhibitor 3-Iodo-L-tyrosine (3IY), which causes acute systemic inhibition of dopamine signaling, and investigate its effects on Pavlovian conditioning. We find that 3IY feeding impairs sugar-reward learning in larvae while leaving task-relevant behavioral faculties intact, and that additional feeding of a precursor of dopamine (L-3,4-dihydroxyphenylalanine, L-DOPA), rescues this impairment. Concerning a different developmental stage and for the aversive valence domain. Moreover, we demonstrate that punishment learning by activating the dopaminergic neuron PPL1-γ1pedc in adult flies is also impaired by 3IY feeding, and can likewise be rescued by L-DOPA. Our findings exemplify the advantages of using a pharmacological approach in combination with the genetic techniques available in D. melanogaster to manipulate neuronal and behavioral function.
Topics: Animals; Behavior, Animal; Biosynthetic Pathways; Dopamine; Dopaminergic Neurons; Drosophila melanogaster; Larva; Learning; Monoiodotyrosine
PubMed: 34106227
DOI: 10.1242/bio.058198 -
Topics in Companion Animal Medicine Jun 2021Dietary exogenous thyrotoxicosis is infrequently observed in pet food. A retrospective evaluation of pet food investigations (PFI) was conducted for 17 dogs, including...
Dietary exogenous thyrotoxicosis is infrequently observed in pet food. A retrospective evaluation of pet food investigations (PFI) was conducted for 17 dogs, including review of medical records, dietary and environmental exposure interviews, food testing, and regulatory action. Five PFIs occurring between 2016 and 2018 involved 7 food products including 2 food types, jerky treats or canned food, made from beef or bison. The dogs' serum thyroid hormone concentrations were evaluated before and after diet change. The foods were tested for active thyroid hormones and hormone precursors using high performance liquid chromatography with inductively coupled plasma mass spectrometry detection. The foods were also examined microscopically. Serum thyroid hormone concentrations of thyroxine (T4) varied depending on the food type consumed. Dogs that consumed dried jerky containing greater T4 concentrations often had increased serum T4 concentrations, whereas dogs that consumed canned products containing greater and 3,4,5- and 3,5,3'-triiodothyronine (T3) concentrations often had decreased serum T4 concentrations. After the diets were changed, serum T4 and T3 concentrations normalized at 1 month. Seven foods containing beef or bison had iodine concentrations greater than 11 mg/kg, and iodine speciation identified variable concentrations of iodide, T4, T3, monoiodotyrosine (MIT), and di-iodotyrosine (DIT). Thyroid gland was found in microscopic sections from one finished food and one ingredient, gullet. FDA performed Health Hazard Evaluations to categorize the exposure risk, and 5 foods were recalled for which the product packaging had not been discarded. Dietary exogenous thyrotoxicosis should be considered in dogs exhibiting clinical signs compatible with hyperthyroidism, especially if consuming beef-based food. A thyroid panel that includes serum iodine, coupled with a thorough feeding history can aid in diagnosis. Thyrotoxicosis is typically reversible after removing the contaminated food from the diet.
Topics: Animal Feed; Animals; Diet; Dog Diseases; Dogs; Retrospective Studies; Thyrotoxicosis; Thyroxine; Triiodothyronine
PubMed: 33556641
DOI: 10.1016/j.tcam.2021.100521 -
Hematology, Transfusion and Cell Therapy 2021Although the efficacy of hydroxyurea (HU) in inhibiting erythrocyte sickling has been well demonstrated, the action of this drug on human neutrophils and the mechanism...
INTRODUCTION
Although the efficacy of hydroxyurea (HU) in inhibiting erythrocyte sickling has been well demonstrated, the action of this drug on human neutrophils and the mechanism by which it improves the manifestations of the disease have not been studied thoroughly. We aimed to investigate the cell viability, along with inflammatory and oxidative markers in the neutrophils of sickle cell anemia (SCA) patients and the effects of HU therapy on these cells, by evaluating the dose-responsiveness.
METHODS
In the present study, 101 patients (45 men and 56 women, aged 18-69 years) with SCA were divided into groups according to the use or not of HU: the SS group (without HU treatment, n = 47) and the SSHU group (under HU treatment, n = 54). The SSHU group was further stratified into subgroups according to the daily dose of the drug that patients already used: SSHU - 0.5 g (n = 19); SSHU - 1 g (n = 26) and SSHU - 1.5-2 g (n = 9). A control group (AA) comprised 50 healthy individuals. Neutrophils isolated from whole blood were analyzed using Trypan Blue, monoiodotyrosine (MTT) and lactate dehydrogenase (LDH) toxicity assays. Myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and concentrations of interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and malonaldehyde (MDA) were also measured.
RESULTS
Neutrophils from SCA patients showed membrane fragility and a significant decrease in cell viability when analyzed by Trypan Blue (p < 0.05), MTT (p < 0.001) and LDH (p = 0.011), compared to the AA group. Levels of inflammatory (MPO, TNF-α, and IL-10) and oxidative markers (SOD, GSH-Px, and MDA) were also altered (p < 0.05) in these cells, showing a significant difference in the SSHU-1g and SSHU - 1.5-2 g groups, compared to the SS group. Treatment with HU reverted the levels of all markers to concentrations similar to those in healthy individuals in a positive dose-effect relationship.
CONCLUSION
The HU did not generate a cytotoxic effect on neutrophils in SCA patients, but it modulated their oxidative and inflammatory mechanisms, promoting cytoprotection with a positive dose-effect.
PubMed: 33051133
DOI: 10.1016/j.htct.2020.07.011 -
Genes & Development Jan 2020In animals, the brain regulates feeding behavior in response to local energy demands of peripheral tissues, which secrete orexigenic and anorexigenic hormones. Although...
In animals, the brain regulates feeding behavior in response to local energy demands of peripheral tissues, which secrete orexigenic and anorexigenic hormones. Although skeletal muscle is a key peripheral tissue, it remains unknown whether muscle-secreted hormones regulate feeding. In , we found that (), the homolog of human bone morphogenetic proteins BMP2 and BMP4, is a muscle-secreted factor (a myokine) that is induced by nutrient sensing and that circulates and signals to the brain. Muscle-restricted dpp RNAi promotes foraging and feeding initiation, whereas overexpression reduces it. This regulation of feeding by muscle-derived Dpp stems from modulation of brain () expression and dopamine biosynthesis. Consistently, Dpp receptor signaling in dopaminergic neurons regulates expression and feeding initiation via the downstream transcriptional repressor Schnurri. Moreover, pharmacologic modulation of TH activity rescues the changes in feeding initiation due to modulation of expression in muscle. These findings indicate that muscle-to-brain endocrine signaling mediated by the myokine Dpp regulates feeding behavior.
Topics: Animals; Brain; DNA-Binding Proteins; Dopamine Agents; Dopaminergic Neurons; Drosophila; Drosophila Proteins; Enzyme Activation; Enzyme Inhibitors; Feeding Behavior; Levodopa; Monoiodotyrosine; Signal Transduction; Transcription Factors; Tyrosine 3-Monooxygenase; Up-Regulation
PubMed: 31831628
DOI: 10.1101/gad.329110.119 -
International Journal of Molecular... Jan 2019Cell-free protein synthesis is useful for synthesizing difficult targets. The site-specific incorporation of non-natural amino acids into proteins is a powerful protein...
Cell-free protein synthesis is useful for synthesizing difficult targets. The site-specific incorporation of non-natural amino acids into proteins is a powerful protein engineering method. In this study, we optimized the protocol for cell extract preparation from the strain RFzero-iy, which is engineered to lack release factor 1 (RF-1). The BL21(DE3)-based RFzero-iy strain exhibited quite high cell-free protein productivity, and thus we established the protocols for its cell culture and extract preparation. In the presence of 3-iodo-l-tyrosine (IY), cell-free protein synthesis using the RFzero-iy-based S30 extract translated the UAG codon to IY at various sites with a high translation efficiency of >90%. In the absence of IY, the RFzero-iy-based cell-free system did not translate UAG to any amino acid, leaving UAG unassigned. Actually, UAG was readily reassigned to various non-natural amino acids, by supplementing them with their specific aminoacyl-tRNA synthetase variants (and their specific tRNAs) into the system. The high incorporation rate of our RFzero-iy-based cell-free system enables the incorporation of a variety of non-natural amino acids into multiple sites of proteins. The present strategy to create the RFzero strain is rapid, and thus promising for RF-1 deletions of various strains genomically engineered for specific requirements.
Topics: Codon, Terminator; Escherichia coli; Escherichia coli Proteins; Monoiodotyrosine; Peptide Termination Factors; Protein Biosynthesis; RNA, Transfer; Subcellular Fractions
PubMed: 30678326
DOI: 10.3390/ijms20030492 -
International Journal of Molecular... Dec 2018The L-shape form of tRNA is maintained by tertiary interactions occurring in the core. Base changes in this domain can cause structural defects and impair tRNA activity....
The L-shape form of tRNA is maintained by tertiary interactions occurring in the core. Base changes in this domain can cause structural defects and impair tRNA activity. Here, we report on a method to safely engineer structural variations in this domain utilizing the noncanonical scaffold of tRNA. First, we constructed a naïve hybrid between archaeal tRNA and tRNA, which consisted of the acceptor and T stems of tRNA and the other parts of tRNA. This hybrid tRNA efficiently translated the UAG codon to 3-iodotyrosine in cells, when paired with a variant of the archaeal tyrosyl-tRNA synthetase. The amber suppression efficiency was slightly lower than that of the "bench-mark" archaeal tRNA suppressor assuming the canonical structure. After a series of modifications to this hybrid tRNA, we obtained two artificial types of tRNA: ZtRNA had an augmented D (auD) helix in a noncanonical form and the D and T loops bound by the standard tertiary base pairs, and YtRNA had a canonical auD helix and non-standard interloop interactions. It was then suggested that the ZtRNA scaffold could also support the glycylation and glutaminylation of tRNA. The synthetic diversity of tRNA would help create new tRNA⁻aminoacyl-tRNA synthetase pairs for reprogramming the genetic code.
Topics: Base Sequence; Codon, Terminator; Escherichia coli; Methanosarcina; Monoiodotyrosine; Nucleic Acid Conformation; RNA, Transfer
PubMed: 30587834
DOI: 10.3390/ijms20010092