scholarly journals Role of Tafazzin in Mitochondrial Function, Development and Disease

2020 ◽  
Vol 8 (2) ◽  
pp. 10
Author(s):  
Michael T. Chin ◽  
Simon J. Conway
Keyword(s):  
Mitochondrial Function ◽  
Human Disease ◽  
Cardiac Development ◽  
Barth Syndrome ◽  
Therapeutic Modality ◽  
Model Organisms ◽  
Adult Disease ◽  
Functional Studies ◽  
Multiple Species

Tafazzin, an enzyme associated with the rare inherited x-linked disorder Barth Syndrome, is a nuclear encoded mitochondrial transacylase that is highly conserved across multiple species and plays an important role in mitochondrial function. Numerous studies have elucidated the mechanisms by which Tafazzin affects mitochondrial function, but its effects on development and susceptibility to adult disease are incompletely understood. The purpose of this review is to highlight previous functional studies across a variety of model organisms, introduce recent studies that show an important role in development, and also to provide an update on the role of Tafazzin in human disease. The profound effects of Tafazzin on cardiac development and adult cardiac homeostasis will be emphasized. These studies underscore the importance of mitochondrial function in cardiac development and disease, and also introduce the concept of Tafazzin as a potential therapeutic modality.

scholarly journals Conserved meiotic mechanisms in the cnidarian Clytia hemisphaerica revealed by Spo11 knockout

2022 ◽  
Author(s):  
Catriona Munro ◽  
Hugo Cadis ◽  
Evelyn Houliston ◽  
Jean-Ren&eacute Huynh
Keyword(s):  
Classical Model ◽  
Fruit Fly ◽  
Model Organisms ◽  
Oocyte Growth ◽  
Alternative Pathways ◽  
Functional Studies ◽  
Evolutionarily Conserved ◽  
Synaptonemal Complex Formation ◽  
Chromosome Movements

During meiosis, each duplicated chromosome pairs and recombines with its unique homolog to ensure the shuffling of genetic information across generations. Functional studies in classical model organisms have revealed a surprising diversity in the chronology and interdependency of the earliest meiotic steps such as chromosome movements, pairing, association via Synaptonemal Complex formation (synapsis), recombination and the formation of chiasmata. A key player is Spo11, an evolutionarily conserved topoisomerase-related transesterase that initiates meiotic recombination via the catalysis of programmed DNA double stranded breaks (DSBs). While DSBs are required for pairing and synapsis in budding yeast and mouse, alternative pathways are employed during female meiosis of the fruit fly and nematode Caenorhabditis elegans. Here, to provide a comparative perspective on meiotic regulation from a distinct animal clade, we chart gametogenesis in Clytia hemisphaerica jellyfish and examine the role of Spo11 using CRISPR-Cas9 mutants, generated clonally from F0 polyp colonies. Spo11 mutant females fail to assemble synaptonemal complexes and chiasmata, such that homologous chromosome pairs disperse during oocyte growth. Subsequent meiotic divisions are abnormal but produce viable progeny. Clytia thus shares an ancient eukaryotic dependence of synapsis and chromosome segregation on Spo11-generated DSBs. It provides a valuable additional experimental model for dissecting meiotic mechanisms during animal gametogenesis, and for building a comparative framework for distinguishing evolutionarily conserved versus flexible features of meiosis.

264The long noncoding RNA H19 modulates cardiac remodeling after infarction

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
O K Choong ◽  
C Y Chen ◽  
J H Lin ◽  
P J Lin ◽  
J H Zhang ◽  
...  
Keyword(s):  
Cardiac Remodeling ◽  
Noncoding Rna ◽  
Cardiac Fibrosis ◽  
Cardiac Development ◽  
Cardiac Fibroblasts ◽  
Noncoding Rnas ◽  
Interacting Protein ◽  
Functional Studies ◽  
Rna Purification

Abstract Noncoding RNAs account for 80% of human transcripts, but functional studies on noncoding RNAs are relatively few and limited. Long noncoding RNAs (lncRNAs) are known to have an important role in cardiac development, and lately, high-throughput RNA sequencing has been extensively utilized to profile and explore the transcriptome landscape of lncRNAs in failing hearts. These studies have revealed that lncRNAs are mostly dysregulated in failing hearts and their expression signature can discriminate failing hearts of different etiologies. H19 is abundantly expressed in failing human hearts and its polymorphism was shown to possess a significant correlation with the risk of coronary artery diseases. In our study using murine hearts, we discovered that H19 was significantly up regulated in the heart after ischemic injury, with predominant expression in cardiac fibroblasts. This finding piqued our interest to further investigate the function of H19 in the heart. We demonstrated that ectopic overexpression of H19 using the AAV approach led to severe cardiac fibrosis in mouse hearts following myocardial infarction. In light of this finding, we generated H19 knockout mice to further investigate the functionality of H19 and we found that cardiac fibrosis was attenuated in these mice. Altogether, these findings suggested that H19 is a fibrosis regulator during cardiac remodeling process after infarction. Due to the multiple regulatory roles of lncRNAs, we then took advantage of chromatin isolation by RNA purification (ChIRP) to identify the H19-interacting protein, YB-1. Surprisingly, mice with YB-1 knockdown displayed severe cardiac fibrosis even without injury. Furthermore, we demonstrated that YB-1 is a transcriptional suppressor of collagen 1A1. Knockout of H19 in YB-1 knockdown partially suppressed Col1a1 expression, which suggests a negative regulatory role of H19 on YB-1 towards the expression of Col1a1. Taking into account all of these findings, we concluded that H19 mediates collagen expression in fibroblasts through the inhibition of YB-1 activity during cardiac remodeling.

scholarly journals Unravelling similarities and differences in the role of circular and linear PVT1 in cancer and human disease

2021 ◽  
Author(s):  
Debora Traversa ◽  
Giorgia Simonetti ◽  
Doron Tolomeo ◽  
Grazia Visci ◽  
Gemma Macchia ◽  
...  
Keyword(s):  
Human Disease ◽  
Therapeutic Potential ◽  
Cell Metabolism ◽  
Exon 2 ◽  
Functional Studies ◽  
Metabolism Regulation ◽  
Non Coding Rna ◽  
Apoptosis Inhibition ◽  
The Many

AbstractThe plasmacytoma variant translocation 1 (PVT1) is a long non-coding RNA gene involved in human disease, mainly in cancer onset/progression. Although widely analysed, its biological roles need to be further clarified. Notably, functional studies on PVT1 are complicated by the occurrence of multiple transcript variants, linear and circular, which generate technical issues in the experimental procedures used to evaluate its impact on human disease. Among the many PVT1 transcripts, the linear PVT1 (lncPVT1) and the circular hsa_circ_0001821 (circPVT1) are frequently reported to perform similar pathologic and pro-tumorigenic functions when overexpressed. The stimulation of cell proliferation, invasion and drug resistance, cell metabolism regulation, and apoptosis inhibition is controlled through multiple targets, including MYC, p21, STAT3, vimentin, cadherins, the PI3K/AKT, HK2, BCL2, and CASP3. However, some of this evidence may originate from an incorrect evaluation of these transcripts as two separate molecules, as they share the lncPVT1 exon-2 sequence. We here summarise lncPVT1/circPVT1 functions by mainly focusing on shared pathways, pointing out the potential bias that may exist when the biological role of each transcript is analysed. These considerations may improve the knowledge about lncPVT1/circPVT1 and their specific targets, which deserve further studies due to their diagnostic, prognostic, and therapeutic potential.

scholarly journals The ‘mitochondrial contact site and cristae organising system’ (MICOS) in health and human disease

2019 ◽  
Vol 167 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Matthew J Eramo ◽  
Valerie Lisnyak ◽  
Luke E Formosa ◽  
Michael T Ryan
Keyword(s):  
Mitochondrial Function ◽  
Human Disease ◽  
Disease Process ◽  
Muscular Dystrophies ◽  
Secondary Effect ◽  
Contact Site ◽  
Direct Role ◽  
Obesity And Diabetes ◽  
Pathological Disease

Abstract The ‘mitochondrial contact site and cristae organising system’ (MICOS) is an essential protein complex that promotes the formation, maintenance and stability of mitochondrial cristae. As such, loss of core MICOS components disrupts cristae structure and impairs mitochondrial function. Aberrant mitochondrial cristae morphology and diminished mitochondrial function is a pathological hallmark observed across many human diseases such as neurodegenerative conditions, obesity and diabetes mellitus, cardiomyopathy, and in muscular dystrophies and myopathies. While mitochondrial abnormalities are often an associated secondary effect to the pathological disease process, a direct role for the MICOS in health and human disease is emerging. This review describes the role of MICOS in the maintenance of mitochondrial architecture and summarizes both the direct and associated roles of the MICOS in human disease.

Ionic homeostasis and subcellular element compartmentation

1990 ◽  
Vol 48 (2) ◽  
pp. 150-151
Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Ionic Homeostasis ◽  
X Ray ◽  
Functional Studies ◽  
Cell Compartments ◽  
X Ray Imaging ◽  
Resolution Electron ◽  
Multiple Cell ◽  
Role Of Zn

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.

scholarly journals The RelA hydrolase domain acts as a molecular switch for (p)ppGpp synthesis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Kumar Sinha ◽  
Kristoffer Skovbo Winther
Keyword(s):  
Active Sites ◽  
Molecular Switch ◽  
Cell Physiology ◽  
Synthetase Activity ◽  
Wild Type ◽  
Functional Studies ◽  
Loop Region ◽  
A Site ◽  
Trna Binding

AbstractBacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity remain elusive. Here, we show a role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using mutagenesis screening and functional studies, we identify a loop region (residues 114–130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wild type RelA. Our data support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity.

scholarly journals When the Balance Tips: Dysregulation of Mitochondrial Dynamics as a Culprit in Disease

2021 ◽  
Vol 22 (9) ◽  
pp. 4617
Author(s):  
Styliana Kyriakoudi ◽  
Anthi Drousiotou ◽  
Petros P. Petrou
Keyword(s):  
Insulin Resistance ◽  
Mitochondrial Function ◽  
Human Disease ◽  
Molecular Mechanisms ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fusion ◽  
Mitochondrial Morphology ◽  
Disease Development ◽  
Pathological Conditions ◽  
Wide Range

Mitochondria are dynamic organelles, the morphology of which is tightly linked to their functions. The interplay between the coordinated events of fusion and fission that are collectively described as mitochondrial dynamics regulates mitochondrial morphology and adjusts mitochondrial function. Over the last few years, accruing evidence established a connection between dysregulated mitochondrial dynamics and disease development and progression. Defects in key components of the machinery mediating mitochondrial fusion and fission have been linked to a wide range of pathological conditions, such as insulin resistance and obesity, neurodegenerative diseases and cancer. Here, we provide an update on the molecular mechanisms promoting mitochondrial fusion and fission in mammals and discuss the emerging association of disturbed mitochondrial dynamics with human disease.

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