Differential expression of mRNA in human thyroid cells depleted of mitochondrial DNA by ethidium bromide treatment

1999 ◽  
Vol 97 (2) ◽  
pp. 207 ◽  
Author(s):  
A.W. THOMAS ◽  
A. MAJID ◽  
E.J. SHERRATT ◽  
J.W. GAGG ◽  
J.C. ALCOLADO

1999 ◽  
Vol 97 (2) ◽  
pp. 207-213 ◽  
Author(s):  
A. W. THOMAS ◽  
A. MAJID ◽  
E. J. SHERRATT ◽  
J. W. GAGG ◽  
J. C. ALCOLADO

A wide variety of human diseases have been associated with defects in mitochondrial DNA (mtDNA). The exact mechanism by which specific mtDNA mutations cause disease is unknown and, although the disparate phenotypes might be explained on the basis of impaired mitochondrial gene function alone, the role of altered nuclear gene expression must also be considered. In recent years, the experimental technique of depleting cells of mtDNA by culturing them with ethidium bromide has become a popular method of studying mitochondrial disorders. However, apart from depleting mtDNA, ethidium bromide may have many other intracellular and nuclear effects. The aim of the present study was to investigate the effects of ethidium bromide treatment on nuclear gene expression. A simian-virus-40-transformed human thyroid cell line was depleted of mtDNA by culture in ethidium bromide, and differential display reverse transcriptase–PCR (DDRT-PCR) was then employed to compare mRNA expression between wild-type, mtDNA-replete (ρ+) and ethidium bromide-treated, mtDNA-depleted (ρ0) cells. Expression of the majority of nuclear-encoded genes, including those for subunits involved in oxidative phosphorylation, remained unaffected by the treatment. Seven clones were found to be underexpressed; three of the clones showed significant similarity with sequences of the human genes encoding RNase L inhibitor, human tissue factor and ARCN1 (archain vesicle transport protein 1), a highly conserved species which is related to vesicle structure and trafficking proteins. We conclude that the effects of ethidium bromide treatment on nuclear gene expression are not simply limited to changes in pathways directly associated with known mitochondrial function. Further studies will be required to elucidate which of these changes are due to mtDNA depletion, ATP deficiency or other disparate effects of ethidium bromide exposure. Given that most genes appear unaffected, the results suggest that depleting cells of mtDNA by ethidium bromide treatment is a valuable approach for the study of mitochondrial mutations by cybrid techniques.



Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.



2020 ◽  
Vol 85 (4) ◽  
pp. 895-901
Author(s):  
Takamitsu Amai ◽  
Tomoka Tsuji ◽  
Mitsuyoshi Ueda ◽  
Kouichi Kuroda

ABSTRACT Mitochondrial dysfunction can occur in a variety of ways, most often due to the deletion or mutation of mitochondrial DNA (mtDNA). The easy generation of yeasts with mtDNA deletion is attractive for analyzing the functions of the mtDNA gene. Treatment of yeasts with ethidium bromide is a well-known method for generating ρ° cells with complete deletion of mtDNA from Saccharomyces cerevisiae. However, the mutagenic effects of ethidium bromide on the nuclear genome cannot be excluded. In this study, we developed a “mito-CRISPR system” that specifically generates ρ° cells of yeasts. This system enabled the specific cleavage of mtDNA by introducing Cas9 fused with the mitochondrial target sequence at the N-terminus and guide RNA into mitochondria, resulting in the specific generation of ρ° cells in yeasts. The mito-CRISPR system provides a concise technology for deleting mtDNA in yeasts.



Endocrine ◽  
2021 ◽  
Author(s):  
Francesca Coperchini ◽  
Gianluca Ricci ◽  
Laura Croce ◽  
Marco Denegri ◽  
Rubina Ruggiero ◽  
...  

Abstract Introduction Angiotensin-converting-enzyme-2 (ACE-2) was demonstrated to be the receptor for cellular entry of SARS-CoV-2. ACE-2 mRNA was identified in several human tissues and recently also in thyroid cells in vitro. Purpose Aim of the present study was to investigate the effect of pro-inflammatory cytokines on the ACE-2 mRNA levels in human thyroid cells in primary cultures. Methods Primary thyroid cell cultures were treated with IFN-γ and TNF-α alone or in combination for 24 h. ACE-2 mRNA levels were measured by RT-PCR. As a control, the levels of IFN-γ inducible chemokine (CXCL10) were measured in the respective cell culture supernatants. Results The mean levels of ACE-2 mRNA increased after treatment with IFN-γ and TNF-α in all the thyroid cell preparations, while the combination treatment did not consistently synergically increase ACE-2-mRNA. At difference, CXCL10 was consistently increased by IFN-γ and synergically further increased by the combination treatment with IFN-γ + TNF-α, with respect to IFN-γ alone. Conclusions The results of the present study show that IFN-γ and, to a lesser extent TNF-α consistently increase ACE-2 mRNA levels in NHT primary cultures. More interestingly, the combined stimulation (proven to be effective according to the synergic effect registered for CXCL10) produces different responses in terms of ACE-2 mRNA modulation. These results would suggest that elevated levels of pro-inflammatory cytokines could facilitate the entering of the virus in cells by further increasing ACE-2 expression and/or account for the different degree of severity of SARS-COV-2 infection. This hypothesis deserves to be confirmed by further specific studies.



1997 ◽  
Vol 25 (2) ◽  
pp. 153-160
Author(s):  
Francesca Mattioli ◽  
Marianna Angiola ◽  
Laura Fazzuoli ◽  
Francesco Razzetta ◽  
Antonietta Martelli

Although primary cultures of human thyroid cells are used for endocrinological and toxicological studies, until now no attention has been paid toward verifying whether the hormonal conditions to which the gland was exposed in vivo prior to surgery could influence in vitro responses. Our findings suggest that the hormonal situation in vivo cannot be used as a predictive indicator of triiodothyronine and thyroxine release and/or S-phase frequency in vitro, either with or without the addition of bovine thyrotropin.



Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1518
Author(s):  
Maria Qatato ◽  
Vaishnavi Venugopalan ◽  
Alaa Al-Hashimi ◽  
Maren Rehders ◽  
Aaron D. Valentine ◽  
...  

Trace amine-associated receptor 1 (rodent Taar1/human TAAR1) is a G protein-coupled receptor that is mainly recognized for its functions in neuromodulation. Previous in vitro studies suggested that Taar1 may signal from intracellular compartments. However, we have shown Taar1 to localize apically and on ciliary extensions in rodent thyrocytes, suggesting that at least in the thyroid, Taar1 may signal from the cilia at the apical plasma membrane domain of thyrocytes in situ, where it is exposed to the content of the follicle lumen containing putative Taar1 ligands. This study was designed to explore mouse Taar1 (mTaar1) trafficking, heterologously expressed in human and rat thyroid cell lines in order to establish an in vitro system in which Taar1 signaling from the cell surface can be studied in future. The results showed that chimeric mTaar1-EGFP traffics to the apical cell surface and localizes particularly to spherical structures of polarized thyroid cells, procilia, and primary cilia upon serum-starvation. Moreover, mTaar1-EGFP appears to form high molecular mass forms, possibly homodimers and tetramers, in stably expressing human thyroid cell lines. However, only monomeric mTaar1-EGFP was cell surface biotinylated in polarized human thyrocytes. In polarized rat thyrocytes, mTaar1-EGFP is retained in the endoplasmic reticulum, while cilia were reached by mTaar1-EGFP transiently co-expressed in combination with an HA-tagged construct of the related mTaar5. We conclude that Taar1 trafficking to cilia depends on their integrity. The results further suggest that an in vitro cell model was established that recapitulates Taar1 trafficking in thyrocytes in situ, in principle, and will enable studying Taar1 signaling in future, thus extending our general understanding of its potential significance for thyroid autoregulation.



1986 ◽  
Vol 43 (10) ◽  
pp. 1866-1872 ◽  
Author(s):  
Lucia Irene González-Villaseñor ◽  
Amanda M. Burkhoff ◽  
Víctor Corces ◽  
Dennis A. Powers

Analysis of mitochondrial DNA endonuclease restriction patterns is a powerful tool for studying related species and variation within species. The ethidium bromide staining technique has limited the number of digestions of mitochondrial DNA per individual. Because 32P-end-labeling also imposes severe limitations, we have resorted to cloning the fish (Fundulus heteroclitus) mitochondrial genome in the lambda replacement vector EMBL-3. The clone was used as a radioactive probe via Southern blotting to detect mitochondrial DNA restriction fragments obtained by multiple restriction endonuclease digestions from small amounts of tissue. This technique offers much greater sensitivity than ethidium bromide staining. Moreover, it eliminates the expense and time to obtain highly purified mitochondrial DNA for the 32P-end-labeling procedure. It is also useful when the mtDNA is prepared from frozen tissue which has been a problem with the 32P-end-labeling technique. Because the cloned mitochondrial DNA has a high degree of cross-hybridization with the mitochondrial DNA of certain other fishes, it can be used to probe the mitochondrial DNA restriction patterns of a variety of fish species. However, its usefulness is restricted by the degree of relatedness to the species being cloned.



1960 ◽  
Vol 20 (2) ◽  
pp. 83-NP ◽  
Author(s):  
W. J. IRVINE

SUMMARY Human thyroid cells were grown in tissue culture in media containing normal human serum, Hashimoto serum, and rabbit sera containing antibodies to purified human thyroglobulin and to crude thyroid extract, respectively. The thyroid cells grew equally well in all media, with the exception of the rabbit serum containing antibodies to crude thyroid extract. Intact thyroid cells obtained from tissue culture failed to fix Hashimoto antibodies in the presence of complement, whereas the constituents of disrupted thyroid cells gave a strongly positive complement-fixation test with Hashimoto serum. It is therefore suggested that the intact thyroid cell is impermeable to complement-fixing Hashimoto antibody. The evidence afforded by the present work adds further weight to the belief that Hashimoto's disease may not be due to a simple auto-immunizing process consequent upon the interaction of thyroid antigen and the known circulating auto-antibodies. Evidence in support of an alternative hypothesis involving 'cell-bound' antibodies with disruption of the follicular basement membrane is discussed.



1997 ◽  
Vol 136 (5) ◽  
pp. 508-515 ◽  
Author(s):  
Simone A R van de Graaf ◽  
Erwin Pauws ◽  
Jan J M de Vijlder ◽  
Carrie Ris-Stalpers

Abstract We developed a transient transfection system for human thyroglobulin (TG) cDNA in both human thyroid cells and in COS-1 cells. Four overlapping TG cDNA fragments were amplified by reverse transcription-PCR from RNA of normal thyroid tissue. The most 5′ fragment includes the natural translation initiation site and the sequence encoding the signal peptide (SP). After subcloning, the nucleotide sequence was determined and compared with the published human sequence, resulting in the detection of 30 nucleotide variations. For validation purposes, all variations were screened in 6–12 normal human alleles. Twenty-one were present in all screened alleles and have to be revised in the published nucleotide sequence. Since one variation concerns a triplet insertion, the coding sequence of the mature human thyroglobulin is 8307 nucleotides encoding 2750 amino acids. The TG cDNA constructs were transiently transfected in HTori 3 and COS-1 cells and protein expression was detected using a polyclonal anti-human-TG on fixed cells and after SDS-PAGE. In both cell-lines all four TG protein fragments were expressed. The mannose structures detected on the proteins by lectins and localization after expression in the cells suggest that only the N-terminal TG fragment (containing the SP) is directed to the endoplasmatic reticulum but is unable to reach the Golgi complex. The described expression system in human thyrocytes will be a helpful tool in studying the structure–function relationship of human TG in thyroid hormonogenesis. European Journal of Endocrinology 136 508–515



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