scholarly journals Structure, Activity and Function of the MLL2 (KMT2B) Protein Lysine Methyltransferase

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 823
Author(s):  
Alexia Klonou ◽  
Sarantis Chlamydas ◽  
Christina Piperi
Keyword(s):  
Germ Line ◽  
Early Stage ◽  
Critical Role ◽  
Specific Gene ◽  
Gene Promoters ◽  
Terminal Set ◽  
Gene Sets ◽  
Functional Aspects ◽  
Lysine Methyltransferase ◽  
And Function

The Mixed Lineage Leukemia 2 (MLL2) protein, also known as KMT2B, belongs to the family of mammalian histone H3 lysine 4 (H3K4) methyltransferases. It is a large protein of 2715 amino acids, widely expressed in adult human tissues and a paralog of the MLL1 protein. MLL2 contains a characteristic C-terminal SET domain responsible for methyltransferase activity and forms a protein complex with WRAD (WDR5, RbBP5, ASH2L and DPY30), host cell factors 1/2 (HCF 1/2) and Menin. The MLL2 complex is responsible for H3K4 trimethylation (H3K4me3) on specific gene promoters and nearby cis-regulatory sites, regulating bivalent developmental genes as well as stem cell and germinal cell differentiation gene sets. Moreover, MLL2 plays a critical role in development and germ line deletions of Mll2 have been associated with early growth retardation, neural tube defects and apoptosis that leads to embryonic death. It has also been involved in the control of voluntary movement and the pathogenesis of early stage childhood dystonia. Additionally, tumor-promoting functions of MLL2 have been detected in several cancer types, including colorectal, hepatocellular, follicular cancer and gliomas. In this review, we discuss the main structural and functional aspects of the MLL2 methyltransferase with particular emphasis on transcriptional mechanisms, gene regulation and association with diseases.

scholarly journals The Roles of the Histone Protein Modifier EZH2 in the Uterus and Placenta

Epigenomes ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 20
Author(s):  
Ana M. Mesa ◽  
Cheryl S. Rosenfeld ◽  
Geetu Tuteja ◽  
Theresa I. Medrano ◽  
Paul S. Cooke
Keyword(s):  
Critical Role ◽  
Histone H3 ◽  
Gene Promoter ◽  
Epigenetic Changes ◽  
Promoter Regions ◽  
Polycomb Repressive Complex 2 ◽  
Gene Sets ◽  
Ezh2 Expression ◽  
And Function ◽  
Transcription Enhancer

Epigenetic modifications regulate normal physiological, as well as pathological processes in various organs, including the uterus and placenta. Both organs undergo dramatic and rapid restructuring that depends upon precise orchestration of events. Epigenetic changes that alter transcription and translation of gene-sets regulate such responses. Histone modifications alter the chromatin structure, thereby affecting transcription factor access to gene promoter regions. Binding of histones to DNA is regulated by addition or removal of subunit methyl and other groups, which can inhibit or stimulate transcription. Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of polycomb repressive complex 2 (PRC2) that catalyzes tri-methylation of histone H3 at Lys 27 (H3K27me3) and subsequently suppresses transcription of genes bound by such histones. Uterine EZH2 expression exerts a critical role in development and function of this organ with deletion of this gene resulting in uterine hyperplasia and expression of cancer-associated transcripts. Elucidating the roles of EZH2 in uterus and placenta is essential as EZH2 dysregulation is associated with several uterine and placental pathologies. Herein, we discuss EZH2 functions in uterus and placenta, emphasizing its physiological and pathological importance.

Critical Role Of Jak2 In The Maintenance and Function Of Adult Hematopoietic Stem Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1180-1180
Author(s):  
Hajime Akada ◽  
Saeko Akada ◽  
Golam Mohi
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Receptor Protein ◽  
Specific Gene ◽  
Hematopoietic Stem ◽  
And Function

Abstract Hematopoietic stem cells (HSCs) play an essential role in the long-term maintenance of hematopoiesis. Various intracellular signaling proteins, transcription factors and extracellular matrix proteins contribute to the maintenance and function of HSCs. Jak2, a member of the Janus family of non-receptor protein tyrosine kinases, is activated in response to a variety of cytokines. It has been shown that germ-line deletion of Jak2 results in embryonic lethality whereas post-natal or adult stage deletion of Jak2 results in anemia and thrombocytopenia in mice. However, the role of Jak2 in the maintenance and function of adult HSCs has remained elusive. Understanding the normal function of Jak2 in adult HSC/progenitors is of considerable significance since mutations in Jak2 have been associated with several myeloproliferative neoplasms (MPNs), and most patients treated with Jak2 inhibitors exhibit significant hematopoietic toxicities. To assess the role of Jak2 in adult HSCs, we have utilized a conditional Jak2 knock-out (Jak2 floxed) allele and an inducible MxCre line that can efficiently express Cre recombinase in adult HSC/progenitors after injections with polyinosine-polycytosine (pI-pC). We have found that deletion of Jak2 in adult mice results in pancytopenia, bone marrow aplasia and 100% lethality within 25 to 42 days after pI-pC induction. Analysis of the HSC/progenitor compartments revealed that Jak2-deficiency causes marked decrease in long-term HSCs, short-term HSCs, multipotent progenitors and early progenitors of all hematopoietic lineages, indicating a defect at the earliest stage of adult hematopoietic development. We have found that deletion of Jak2 leads to increased HSC cell cycle entry, suggesting that Jak2-deficiency results in loss of quiescence in HSCs. Jak2-deficiency also resulted in significant apoptosis in HSCs. Furthermore Jak2-deficient bone marrow cells were severely defective in reconstituting hematopoiesis in lethally-irradiated recipient animals. Competitive repopulations experiments also show that Jak2 is essential for HSC functional activity. We also have confirmed that the requirement for Jak2 in HSCs is cell-autonomous. To gain insight into the mechanism by which Jak2 controls HSC maintenance and function, we have performed phospho flow analysis on HSC-enriched LSK (lin-Sca-1+c-kit+) cells. TPO and SCF-evoked Akt and Erk activation was significantly reduced in Jak2-deficient LSK compared with control LSK. Stat5 phosphorylation in response to TPO was also completely inhibited in Jak2-deficient LSK cells. In addition, we observed significantly increased intracellular reactive oxygen species (ROS) levels and enhanced activation of p38 MAPK in Jak2-deficient LSK cells, consistent with the loss of quiescence observed in Jak2-deficient HSCs. Treatment with ROS scavenger N-acetyl cysteine partially rescued the defects in Jak2-deficient HSCs in reconstituting hematopoiesis in lethally irradiated recipient animals. Gene expression analysis revealed significant downregulation of HSC-specific gene sets in Jak2-deficient LSK cells. Taken together, our data strongly suggest that Jak2 plays a critical role in the maintenance of quiescence, survival and self-renewal of adult HSCs. Disclosures: No relevant conflicts of interest to declare.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

scholarly journals NKL Homeobox Gene VENTX Is Part of a Regulatory Network in Human Conventional Dendritic Cells

2021 ◽  
Vol 22 (11) ◽  
pp. 5902
Author(s):  
Stefan Nagel ◽  
Claudia Pommerenke ◽  
Corinna Meyer ◽  
Hans G. Drexler
Keyword(s):  
Dendritic Cells ◽  
Transcription Factors ◽  
Cell Lines ◽  
Expression Profiling ◽  
Regulatory Network ◽  
Homeobox Gene ◽  
Leukemia Cell Line ◽  
Specific Gene ◽  
Rna Seq ◽  
And Function

Recently, we documented a hematopoietic NKL-code mapping physiological expression patterns of NKL homeobox genes in human myelopoiesis including monocytes and their derived dendritic cells (DCs). Here, we enlarge this map to include normal NKL homeobox gene expressions in progenitor-derived DCs. Analysis of public gene expression profiling and RNA-seq datasets containing plasmacytoid and conventional dendritic cells (pDC and cDC) demonstrated HHEX activity in both entities while cDCs additionally expressed VENTX. The consequent aim of our study was to examine regulation and function of VENTX in DCs. We compared profiling data of VENTX-positive cDC and monocytes with VENTX-negative pDC and common myeloid progenitor entities and revealed several differentially expressed genes encoding transcription factors and pathway components, representing potential VENTX regulators. Screening of RNA-seq data for 100 leukemia/lymphoma cell lines identified prominent VENTX expression in an acute myelomonocytic leukemia cell line, MUTZ-3 containing inv(3)(q21q26) and t(12;22)(p13;q11) and representing a model for DC differentiation studies. Furthermore, extended gene analyses indicated that MUTZ-3 is associated with the subtype cDC2. In addition to analysis of public chromatin immune-precipitation data, subsequent knockdown experiments and modulations of signaling pathways in MUTZ-3 and control cell lines confirmed identified candidate transcription factors CEBPB, ETV6, EVI1, GATA2, IRF2, MN1, SPIB, and SPI1 and the CSF-, NOTCH-, and TNFa-pathways as VENTX regulators. Live-cell imaging analyses of MUTZ-3 cells treated for VENTX knockdown excluded impacts on apoptosis or induced alteration of differentiation-associated cell morphology. In contrast, target gene analysis performed by expression profiling of knockdown-treated MUTZ-3 cells revealed VENTX-mediated activation of several cDC-specific genes including CSFR1, EGR2, and MIR10A and inhibition of pDC-specific genes like RUNX2. Taken together, we added NKL homeobox gene activities for progenitor-derived DCs to the NKL-code, showing that VENTX is expressed in cDCs but not in pDCs and forms part of a cDC-specific gene regulatory network operating in DC differentiation and function.

scholarly journals The lung–gut axis during viral respiratory infections: the impact of gut dysbiosis on secondary disease outcomes

2021 ◽  
Author(s):  
Valentin Sencio ◽  
Marina Gomes Machado ◽  
François Trottein
Keyword(s):  
Gut Microbiota ◽  
Bacterial Infections ◽  
Respiratory Infections ◽  
Critical Role ◽  
Good Health ◽  
Disease Outcomes ◽  
And Function ◽  
Viral Respiratory Infections ◽  
The Impact ◽  
Viral Respiratory

AbstractBacteria that colonize the human gastrointestinal tract are essential for good health. The gut microbiota has a critical role in pulmonary immunity and host’s defense against viral respiratory infections. The gut microbiota’s composition and function can be profoundly affected in many disease settings, including acute infections, and these changes can aggravate the severity of the disease. Here, we discuss mechanisms by which the gut microbiota arms the lung to control viral respiratory infections. We summarize the impact of viral respiratory infections on the gut microbiota and discuss the potential mechanisms leading to alterations of gut microbiota’s composition and functions. We also discuss the effects of gut microbial imbalance on disease outcomes, including gastrointestinal disorders and secondary bacterial infections. Lastly, we discuss the potential role of the lung–gut axis in coronavirus disease 2019.

scholarly journals Common and rare genetic variants that could contribute to severe otitis media in an Australian Aboriginal population

2021 ◽  
Author(s):  
Sarra E Jamieson ◽  
Michaela Fakiola ◽  
Dave Tang ◽  
Elizabeth Scaman ◽  
Genevieve Syn ◽  
...  
Keyword(s):  
Hair Cell ◽  
Otitis Media ◽  
Genetic Risk ◽  
Transforming Growth Factor ◽  
Rare Variants ◽  
Protein Coding ◽  
Gene Sets ◽  
Growth Factor Signalling ◽  
Rare Genetic Variants ◽  
And Function

Abstract Background Our goal was to identify genetic risk factors for severe otitis media (OM) in Aboriginal Australians. Methods Illumina ® Omni2.5 BeadChip and imputed data were compared between 21 children with severe OM (multiple episodes chronic suppurative OM and/or perforations or tympanic sclerosis) and 370 individuals without this phenotype, followed by FUnctional Mapping and Annotation (FUMA). Exome data filtered for common (EXaC_all≥0.1) putative deleterious variants influencing protein coding (CADD-scaled scores ≥ 15) were used to compare 15 severe OM cases with 9 mild cases (single episode of acute OM recorded over ≥ 3 consecutive years). Rare (ExAC_all≤0.01) such variants were filtered for those present only in severe OM. Enrichr was used to determine enrichment of genes contributing to pathways/processes relevant to OM. Results FUMA analysis identified two plausible genetic risk loci for severe OM: NR3C1 (Pimputed_1000G=3.62x10 -6) encoding the glucocorticoid receptor, and NREP (Pimputed_1000G=3.67x10 -6) encoding neuronal regeneration related protein. Exome analysis showed: (i) association of severe OM with variants influencing protein coding (CADD-scaled ≥ 15) in a gene-set (GRXCR1, CDH23, LRP2, FAT4, ARSA, EYA4) enriched for Mammalian Phenotype Level 4 abnormal hair cell stereociliary bundle morphology and related phenotypes; (ii) rare variants influencing protein coding only seen in severe OM provided gene-sets enriched for “abnormal ear” (LMNA, CDH23, LRP2, MYO7A, FGFR1), integrin interactions, transforming growth factor signalling, and cell projection phenotypes including hair cell stereociliary bundles and cilium assembly. Conclusions This study highlights interacting genes and pathways related to cilium structure and function that may contribute to extreme susceptibility to OM in Aboriginal Australian children.

scholarly journals Mechanosensation and Mechanotransduction by Lymphatic Endothelial Cells Act as Important Regulators of Lymphatic Development and Function

2021 ◽  
Vol 22 (8) ◽  
pp. 3955
Author(s):  
László Bálint ◽  
Zoltán Jakus
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Mechanical Forces ◽  
Lymphatic Endothelial Cells ◽  
Lymphatic Development ◽  
And Function ◽  
The Impact

Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.

scholarly journals Expression and function of Smad7 in autoimmune and inflammatory diseases

2021 ◽  
Author(s):  
Yiping Hu ◽  
Juan He ◽  
Lianhua He ◽  
Bihua Xu ◽  
Qingwen Wang
Keyword(s):  
Posttranscriptional Regulation ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Inflammatory Diseases ◽  
Kidney Diseases ◽  
Critical Role ◽  
Transforming Growth Factor Β ◽  
Negative Regulator ◽  
Signaling Mechanism ◽  
And Function

AbstractTransforming growth factor-β (TGF-β) plays a critical role in the pathological processes of various diseases. However, the signaling mechanism of TGF-β in the pathological response remains largely unclear. In this review, we discuss advances in research of Smad7, a member of the I-Smads family and a negative regulator of TGF-β signaling, and mainly review the expression and its function in diseases. Smad7 inhibits the activation of the NF-κB and TGF-β signaling pathways and plays a pivotal role in the prevention and treatment of various diseases. Specifically, Smad7 can not only attenuate growth inhibition, fibrosis, apoptosis, inflammation, and inflammatory T cell differentiation, but also promotes epithelial cells migration or disease development. In this review, we aim to summarize the various biological functions of Smad7 in autoimmune diseases, inflammatory diseases, cancers, and kidney diseases, focusing on the molecular mechanisms of the transcriptional and posttranscriptional regulation of Smad7.

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