scholarly journals Cochlear Fibrocyte and Osteoblast Lineages Expressing Type 2 Deiodinase Identified with a Dio2CreERt2 Allele

Endocrinology ◽  
2021 ◽  
Vol 162 (12) ◽  
Author(s):  
Lily Ng ◽  
Ye Liu ◽  
Hong Liu ◽  
Douglas Forrest
Keyword(s):  
Thyroid Hormone ◽  
Active Form ◽  
Organ Of Corti ◽  
Cell Types ◽  
Spiral Ligament ◽  
Vascular Networks ◽  
Fluorescent Reporter ◽  
Bony Labyrinth ◽  
Auditory Development

Abstract Type 2 deiodinase (Dio2) amplifies levels of 3,5,3′-L-triiodothyronine (T3), the active form of thyroid hormone, and is essential for cochlear maturation and auditory development. However, cellular routes for endocrine signaling in the compartmentalized, anatomically complex cochlea are little understood. Dio2 generates T3 from thyroxine (T4), a more abundant thyroid hormone precursor in the circulation, and is dramatically induced in the cochlea before the onset of hearing. The evidence implies that specific Dio2-expressing cell types critically mediate T3 signaling but these cell types are poorly defined because Dio2 is expressed transiently at low levels. Here, using a Dio2CreERt2 knockin that activates a fluorescent reporter, we define Dio2-expressing cochlear cell types at high resolution in male or female mice. Dio2-positive cells were detected in vascularized supporting tissues but not in avascular internal epithelia, indicating segregation of T3-generating and T3-responding tissues. In the spiral ligament and spiral limbus, Dio2-positive fibrocytes clustered around vascular networks that convey T4 into cochlear tissues. In the otic capsule, Dio2-positive osteoblasts localized at cartilage surfaces as the bony labyrinth matures. We corroborated the identities of Dio2-positive lineages by RNA-sequencing of individual cells. The results suggest a previously unrecognized role for fibrocytes in mediating hormonal signaling. We discuss a model whereby fibrocytes mediate paracrine-like control of T3 signaling to the organ of Corti and epithelial target tissues.

scholarly journals Dio2-CreErt2 Knockin Model to Identify T3-Generating Cells That Express Type 2 Deiodinase in Tissues

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A975-A975
Author(s):  
Lily Ng ◽  
Ye Liu ◽  
Hong Liu ◽  
Douglas Forrest
Keyword(s):  
Cell Types ◽  
Brain Regions ◽  
Sensory Epithelium ◽  
Tamoxifen Treatment ◽  
Blood Capillary ◽  
Spiral Ligament ◽  
Bone Maturation ◽  
Cellular Resolution ◽  
Supply Analysis

Abstract Background: Thyroid hormone promotes many developmental and homeostatic functions. Apart from adequate circulating levels, the concentration of the active hormone T3 within tissues may be amplified by type 2 deiodinase (Dio2) by conversion from the precursor T4. Dio2 is critical in auditory development, bone maturation, brain function and control of the hypothalamic-pituitary-thyroid axis. Despite its crucial role, an obstacle to studying Dio2 is that the protein has a short half-life, is at low levels and is often transiently expressed, making it difficult to identify Dio2 in tissues at cellular resolution. Methods: We derived a Dio2-CreERt2 knockin mouse that expresses tamoxifen-dependent Cre recombinase from the endogenous Dio2 gene. When crossed onto Ai6 reporter mice, following tamoxifen treatment, Dio2-CreERt2 expression is detected as fluorescent signal in specific cells in brain regions, pituitary, and other tissues. We showed previously that Dio2 is essential for hearing with rising expression levels in the cochlea prior to onset of hearing. The Dio2-CreERt2 model identified positive cell types in the cochlear spiral ligament, septal divisions and modiolus around the sensory epithelium. Dio2-positive fibrocytes were adjacent to and extended projections around blood capillary networks, the source of T4 supply. Transcriptome analysis of isolated positive cells revealed bone lineage-related origins for many of these cells. Conclusion: The Dio2-CreERt2 model detects Dio2 expression sensitively at cellular resolution. In the cochlea, Dio2-positive cell types reside in vascularized support tissues, suggesting combined endocrine and paracrine-like control of the T3 supply. Analysis of cell origins suggests novel interactions between endocrine and skeletal systems in promoting T3 action required for hearing.

scholarly journals Type 2 iodothyronine deiodinase is highly expressed in germ cells of adult rat testis

2007 ◽  
Vol 194 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Simone Magagnin Wajner ◽  
Márcia dos Santos Wagner ◽  
Rossana C N Melo ◽  
Gleydes G Parreira ◽  
Hélio Chiarini-Garcia ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Real Time ◽  
Germ Cells ◽  
Real Time Pcr ◽  
Cell Types ◽  
Iodothyronine Deiodinase ◽  
Rat Testis ◽  
Cell Fractions

The testis has been classically described as a thyroid hormone unresponsive tissue, but recent studies indicate that these hormones might play an important role in developing testes. We have previously demonstrated that type 2 iodothyronine deiodinase (D2), a thyroid hormone-activating enzyme, is expressed in adult rodent testis and that its activity is induced by hypothyroidism. Nevertheless, the precise location of D2 in testis is not known. The aim of the present work was to determine the testicular cell types in which D2 is expressed using real-time PCR analysis, in situ hybridization histochemistry, and determination of D2 activity in cell fractions isolated from adult euthyroid and/or hypothyroid rat testis. The D2 mRNA levels in germ cells were higher than those from somatic cells (6.94 ± 1.49 vs 2.32 ± 0.79 arbitrary units (au); P = 0.017). Hypothyroidism increased D2 expression in germ cells (6.94 ± 1.49 vs 8.78 ± 5.43 au, P = 0.002) but did not change D2 transcripts in somatic cells significantly (2.12 ± 0.79 vs 2.88 ± 1.39 au, P = 0.50). In situ hybridization analysis showed that D2 mRNA is specifically present in elongated spermatids undergoing differentiation, whereas other germ cell types and Sertoli cells of seminiferous epithelium and the interstitial cells were virtually negative for this enzyme. The enzyme activity measured in germ and somatic isolated cell fractions (0.23 ± 0.003 vs 0.02 ± 0.013 fmol/min per mg protein respectively; P < 0.001) further confirmed the real-time PCR and in situ hybridization results. Hence, our findings demonstrated that D2 is predominantly expressed in elongated spermatids, suggesting that thyroid hormone might have a direct effect on spermatogenesis in the adult rats.

Thyroid Hormone Deiodinases: Dynamic Switches in Developmental Transitions

Endocrinology ◽  
2021 ◽  
Author(s):  
Arturo Hernandez ◽  
M Elena Martinez ◽  
Lily Ng ◽  
Douglas Forrest
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Hormone Receptors ◽  
Active Form ◽  
Cell Types ◽  
Tissue Response ◽  
Human Thyroid ◽  
Specific Cell ◽  
Local Concentration ◽  
Developmental Transitions

Abstract Thyroid hormones exert pleiotropic, essential actions in mammalian, including human, development. These actions depend upon provision of thyroid hormones in the circulation but also to a remarkable extent upon deiodinase enzymes in target tissues that amplify or deplete the local concentration of the primary active form of the hormone T3 (3,5,3'-triiodothyronine), the high affinity ligand for thyroid hormone receptors. Genetic analyses in mice have revealed key roles for activating (DIO2) and inactivating (DIO3) deiodinases in cell differentiation fates and tissue maturation, ultimately promoting neonatal viability, growth, fertility, brain development and behavior, as well as metabolic, endocrine and sensory functions. An emerging paradigm is how the opposing activities of DIO2 and DIO3 are coordinated, providing a dynamic switch that controls the developmental timing of a tissue response, often during neonatal and maturational transitions. A second paradigm is how cell-cell communication within a tissue determines the response to T3. Deiodinases in specific cell types, often strategically located near to blood vessels that convey thyroid hormones into the tissue, can regulate neighboring cell types, suggesting a paracrine-like layer of control of T3 action. We discuss deiodinases as switches for developmental transitions and their potential to influence tissue dysfunction in human thyroid disorders.

scholarly journals A Protective Role for Type 3 Deiodinase, a Thyroid Hormone-Inactivating Enzyme, in Cochlear Development and Auditory Function

Endocrinology ◽  
2008 ◽  
Vol 150 (4) ◽  
pp. 1952-1960 ◽  
Author(s):  
Lily Ng ◽  
Arturo Hernandez ◽  
Wenxuan He ◽  
Tianying Ren ◽  
Maya Srinivas ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormone Receptor ◽  
Stria Vascularis ◽  
Active Form ◽  
Spiral Ganglion ◽  
Protective Role ◽  
Auditory Function ◽  
Cochlear Development ◽  
Type 3

Thyroid hormone is necessary for cochlear development and auditory function, but the factors that control these processes are poorly understood. Previous evidence indicated that in mice, the serum supply of thyroid hormone is augmented within the cochlea itself by type 2 deiodinase, which amplifies the level of T3, the active form of thyroid hormone, before the onset of hearing. We now report that type 3 deiodinase, a thyroid hormone-inactivating enzyme encoded by Dio3, is expressed in the immature cochlea before type 2 deiodinase. Dio3−/− mice display auditory deficits and accelerated cochlear differentiation, contrasting with the retardation caused by deletion of type 2 deiodinase. The Dio3 mRNA expression pattern in the greater epithelial ridge, stria vascularis, and spiral ganglion partly overlaps with that of thyroid hormone receptor β (TRβ), the T3 receptor that is primarily responsible for auditory development. The proposal that type 3 deiodinase prevents premature stimulation of TRβ was supported by deleting TRβ, which converted the Dio3−/− cochlear phenotype from one of accelerated to one of delayed differentiation. The results indicate a protective role for type 3 deiodinase in hearing. The auditory system illustrates the considerable extent to which tissues can autoregulate their developmental response to thyroid hormone through both type 2 and 3 deiodinases.

Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector

1992 ◽  
Vol 67 (01) ◽  
pp. 154-160 ◽  
Author(s):  
P Meulien ◽  
M Nishino ◽  
C Mazurier ◽  
K Dott ◽  
G Piétu ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Von Willebrand Factor ◽  
Human Fibroblasts ◽  
Active Form ◽  
Cell Types ◽  
Biologically Active ◽  
L Cells ◽  
Von Willebrand ◽  
Different Cell Types ◽  
Willebrand Factor

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.

scholarly journals Selective deletion of SHIP-1 in hematopoietic cells in mice leads to severe lung inflammation involving ILC2 cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xujun Ye ◽  
Fengrui Zhang ◽  
Li Zhou ◽  
Yadong Wei ◽  
Li Zhang ◽  
...  
Keyword(s):  
Lung Inflammation ◽  
Airway Remodeling ◽  
Pulmonary Inflammation ◽  
Hematopoietic Cells ◽  
Cell Lineage ◽  
Allergic Inflammation ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Whole Body

AbstractSrc homology 2 domain–containing inositol 5-phosphatase 1 (SHIP-1) regulates the intracellular levels of phosphotidylinositol-3, 4, 5-trisphosphate, a phosphoinositide 3–kinase (PI3K) product. Emerging evidence suggests that the PI3K pathway is involved in allergic inflammation in the lung. Germline or induced whole-body deletion of SHIP-1 in mice led to spontaneous type 2-dominated pulmonary inflammation, demonstrating that SHIP-1 is essential for lung homeostasis. However, the mechanisms by which SHIP-1 regulates lung inflammation and the responsible cell types are still unclear. Deletion of SHIP-1 selectively in B cells, T cells, dendritic cells (DC) or macrophages did not lead to spontaneous allergic inflammation in mice, suggesting that innate immune cells, particularly group 2 innate lymphoid cells (ILC2 cells) may play an important role in this process. We tested this idea using mice with deletion of SHIP-1 in the hematopoietic cell lineage and examined the changes in ILC2 cells. Conditional deletion of SHIP-1 in hematopoietic cells in Tek-Cre/SHIP-1 mice resulted in spontaneous pulmonary inflammation with features of type 2 immune responses and airway remodeling like those seen in mice with global deletion of SHIP-1. Furthermore, when compared to wild-type control mice, Tek-Cre/SHIP-1 mice displayed a significant increase in the number of IL-5/IL-13 producing ILC2 cells in the lung at baseline and after stimulation by allergen Papain. These findings provide some hints that PI3K signaling may play a role in ILC2 cell development at baseline and in response to allergen stimulation. SHIP-1 is required for maintaining lung homeostasis potentially by restraining ILC2 cells and type 2 inflammation.

Effects of cytochrome c on the mitochondrial apoptosis-induced channel MAC

2004 ◽  
Vol 286 (5) ◽  
pp. C1109-C1117 ◽  
Author(s):  
Liang Guo ◽  
Dawn Pietkiewicz ◽  
Evgeny V. Pavlov ◽  
Sergey M. Grigoriev ◽  
John J. Kasianowicz ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Outer Membrane ◽  
Cell Types ◽  
Rnase A ◽  
Mitochondrial Outer Membrane ◽  
Dependent Manner ◽  
Mitochondrial Apoptosis ◽  
Noise Type ◽  
Voltage Dependent

Recent studies indicate that cytochrome c is released early in apoptosis without loss of integrity of the mitochondrial outer membrane in some cell types. The high-conductance mitochondrial apoptosis-induced channel (MAC) forms in the outer membrane early in apoptosis of FL5.12 cells. Physiological (micromolar) levels of cytochrome c alter MAC activity, and these effects are referred to as types 1 and 2. Type 1 effects are consistent with a partitioning of cytochrome c into the pore of MAC and include a modest decrease in conductance that is dose and voltage dependent, reversible, and has an increase in noise. Type 2 effects may correspond to “plugging” of the pore or destabilization of the open state. Type 2 effects are a dose-dependent, voltage-independent, and irreversible decrease in conductance. MAC is a heterogeneous channel with variable conductance. Cytochrome c affects MAC in a pore size-dependent manner, with maximal effects of cytochrome c on MAC with conductance of 1.9–5.4 nS. The effects of cytochrome c, RNase A, and high salt on MAC indicate that size, rather than charge, is crucial. The effects of dextran molecules of various sizes indicate that the pore diameter of MAC is slightly larger than that of 17-kDa dextran, which should be sufficient to allow the passage of 12-kDa cytochrome c. These findings are consistent with the notion that MAC is the pore through which cytochrome c is released from mitochondria during apoptosis.

Mechanisms implicated in the growth regulatory effects of vitamin D in breast cancer.

2002 ◽  
pp. 45-59 ◽  
Author(s):  
K W Colston ◽  
C M√∏rk Hansen
Keyword(s):  
Breast Cancer ◽  
Vitamin D ◽  
Bone Mineralization ◽  
Active Form ◽  
Cell Types ◽  
Cell Cycle Regulators ◽  
Dihydroxyvitamin D ◽  
Cell Growth And Differentiation ◽  
Regulatory Effects ◽  
Apoptotic Effects

It is now well established that, in addition to its central role in the maintenance of extracellular calcium levels and bone mineralization, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), the active form of vitamin D, also acts as a modulator of cell growth and differentiation in a number of cell types, including breast cancer cells. The anti-proliferative effects of 1,25(OH)(2)D(3) have been linked to suppression of growth stimulatory signals and potentiation of growth inhibitory signals, which lead to changes in cell cycle regulators such as p21(WAF-1/CIP1) and p27(kip1), cyclins and retinoblastoma protein as well as induction of apoptosis. Such studies have led to interest in the potential use of 1,25(OH)(2)D(3) in the treatment or prevention of certain cancers. Since this approach is limited by the tendency of 1,25(OH)(2)D(3) to cause hypercalcaemia, synthetic vitamin D analogues have been developed which display separation of the growth regulating effects from calcium mobilizing actions. This review examines mechanisms by which 1,25(OH)(2)D(3) and its active analogues exert both anti-proliferative and pro-apoptotic effects and describes some of the synthetic analogues that have been shown to be of particular interest in relation to breast cancer.

scholarly journals Thyroid Hormone Action in Cerebellum and Cerebral Cortex Development

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Fabrice Chatonnet ◽  
Frédéric Picou ◽  
Teddy Fauquier ◽  
Frédéric Flamant
Keyword(s):  
Cerebral Cortex ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Glial Cell ◽  
Nuclear Receptors ◽  
Target Genes ◽  
Cell Types ◽  
Hormone Action ◽  
Cerebral Cortex Development ◽  
Thyroid Hormone Action

Thyroid hormones (TH, including the prohormone thyroxine (T4) and its active deiodinated derivative 3,,5-triiodo-L-thyronine (T3)) are important regulators of vertebrates neurodevelopment. Specific transporters and deiodinases are required to ensure T3 access to the developing brain. T3 activates a number of differentiation processes in neuronal and glial cell types by binding to nuclear receptors, acting directly on transcription. Only few T3 target genes are currently known. Deeper investigations are urgently needed, considering that some chemicals present in food are believed to interfere with T3 signaling with putative neurotoxic consequences.

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