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1.
Reversal of nucleobase methylation by dioxygenases.
Xu, GL, Bochtler, M
Nature chemical biology. 2020;(11):1160-1169
Abstract
The repertoire of nucleobase methylation in DNA and RNA, introduced by chemical agents or enzymes, is large. Most methylation can be reversed either directly by restoration of the original nucleobase or indirectly by replacement of the methylated nucleobase with an unmodified nucleobase. In many direct and indirect demethylation reactions, ALKBH (AlkB homolog) and TET (ten eleven translocation) hydroxylases play a role. Here, we suggest a chemical classification of methylation types. We then discuss pathways for removal, emphasizing oxidation reactions. We highlight the recently expanded repertoire of ALKBH- and TET-catalyzed reactions and describe the discovery of a TET-like protein that resembles the hydroxylases but uses an alternative co-factor and catalyzes glyceryl transfer rather than hydroxylation.
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2.
Mutations in NBAS and SCYL1, genetic causes of recurrent liver failure in children: Three case reports and a literature review.
Chavany, J, Cano, A, Roquelaure, B, Bourgeois, P, Boubnova, J, Gaignard, P, Hoebeke, C, Reynaud, R, Rhomer, B, Slama, A, et al
Archives de pediatrie : organe officiel de la Societe francaise de pediatrie. 2020;(3):155-159
Abstract
Acute liver failure (ALF) in childhood is a life-threatening emergency. ALF is often caused by drug toxicity, autoimmune hepatitis, inherited metabolic diseases, and infections. However, despite thorough investigations, a cause cannot be determined in approximately 50% of cases. Here, we report three cases with recurrent ALF caused by NBAS and SCYL1 pathogenic variants. These patients did not present with any other phenotypic sign usually associated with NBAS and SCYL1 pathogenic variants. Two of them underwent liver transplantation and are healthy without recurrence of ALF. We propose NBAS and SCYL1 genetic analysis in children with unexplained fever-triggered recurrent ALF even without a typical phenotype.
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3.
Management versus miscues in the cytosolic labile iron pool: The varied functions of iron chaperones.
Philpott, CC, Patel, SJ, Protchenko, O
Biochimica et biophysica acta. Molecular cell research. 2020;(11):118830
Abstract
Iron-containing proteins rely on the incorporation of a set of iron cofactors for activity. The cofactors must be synthesized or assembled from raw materials located within the cell. The chemical nature of this pool of raw material - referred to as the labile iron pool - has become clearer with the identification of micro- and macro-molecules that coordinate iron within the cell. These molecules function as a buffer system for the management of intracellular iron and are the focus of this review, with emphasis on the major iron chaperone protein coordinating the labile iron pool: poly C-binding protein 1.
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4.
The Trinity of cGAS, TLR9, and ALRs Guardians of the Cellular Galaxy Against Host-Derived Self-DNA.
Kumar, V
Frontiers in immunology. 2020;:624597
Abstract
The immune system has evolved to protect the host from the pathogens and allergens surrounding their environment. The immune system develops in such a way to recognize self and non-self and develops self-tolerance against self-proteins, nucleic acids, and other larger molecules. However, the broken immunological self-tolerance leads to the development of autoimmune or autoinflammatory diseases. Pattern-recognition receptors (PRRs) are expressed by immunological cells on their cell membrane and in the cytosol. Different Toll-like receptors (TLRs), Nod-like receptors (NLRs) and absent in melanoma-2 (AIM-2)-like receptors (ALRs) forming inflammasomes in the cytosol, RIG (retinoic acid-inducible gene)-1-like receptors (RLRs), and C-type lectin receptors (CLRs) are some of the PRRs. The DNA-sensing receptor cyclic GMP-AMP synthase (cGAS) is another PRR present in the cytosol and the nucleus. The present review describes the role of ALRs (AIM2), TLR9, and cGAS in recognizing the host cell DNA as a potent damage/danger-associated molecular pattern (DAMP), which moves out to the cytosol from its housing organelles (nucleus and mitochondria). The introduction opens with the concept that the immune system has evolved to recognize pathogens, the idea of horror autotoxicus, and its failure due to the emergence of autoimmune diseases (ADs), and the discovery of PRRs revolutionizing immunology. The second section describes the cGAS-STING signaling pathway mediated cytosolic self-DNA recognition, its evolution, characteristics of self-DNAs activating it, and its role in different inflammatory conditions. The third section describes the role of TLR9 in recognizing self-DNA in the endolysosomes during infections depending on the self-DNA characteristics and various inflammatory diseases. The fourth section discusses about AIM2 (an ALR), which also binds cytosolic self-DNA (with 80-300 base pairs or bp) that inhibits cGAS-STING-dependent type 1 IFN generation but induces inflammation and pyroptosis during different inflammatory conditions. Hence, this trinity of PRRs has evolved to recognize self-DNA as a potential DAMP and comes into action to guard the cellular galaxy. However, their dysregulation proves dangerous to the host and leads to several inflammatory conditions, including sterile-inflammatory conditions autoinflammatory and ADs.
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5.
Expression Analysis of RbBP6 in human cancers: a Prospective biomarker.
Mbita, Z, Hull, R, Mbele, M, Makhafola, T, Dlamini, Z
Anti-cancer drugs. 2019;(8):767-773
Abstract
Retinoblastoma binding protein 6 (RBBP6) is a cancer-related protein that has been implicated in the regulation of cell cycle and apoptosis. RBBP6 isoform 1 has been demonstrated to interact with two tumour suppressors, p53 and pRB. Isoform 1 been shown to regulate p53 through its ubiquitin ligase activity, thus implicating in cell cycle regulation and apoptosis. Isoforms 1 and 2 are multidomain proteins containing a domain with no name (DWNN) domain, a Zinc Finger, a RING Finger, an Rb-binding domain and a p53-binding domain. The RBBP6 isoform 3 comprises the DWNN domain only. Isoform 4 lacks the Rb-binding domain but its role is less understood. RBBP6 isoform 3 has been reported as a cell cycle regulator with anticancer potential. There have been several studies that have clearly demonstrated that RBBP6 may be an important biomarker for cancer diagnosis and a potential drug target for cancer treatment. This work focused on differential expression of RBBP6 transcripts in different cancers, providing detailed analysis of their potential as diagnostic biomarkers for different cancers. These cancers include breast, liver, cervical and colon carcinomas. The expression of RBBP6 transcripts may further provide better understanding of the role of the RBBP6 in carcinogenesis and cell homeostasis.
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6.
The role of new adipokines in gestational diabetes mellitus pathogenesis.
Mierzyński, R, Poniedziałek-Czajkowska, E, Dłuski, D, Leszczyńska-Gorzelak, B
Ginekologia polska. 2018;(4):221-26
Abstract
Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition dur-ing pregnancy. Explanation of the GDM pathogenesis is important due to preventing gestational complications. During pregnancy there are significant changes in maternal metabolism. Many of these changes are influenced by different adi-pokines produced in the placenta and adipose tissue. The exact role of adipokines in the pathogenesis of GDM remains still unknown. Several adipokines have been analysed throughout gestation and their levels have been suggested as biomarkers of maternal-perinatal outcomes. Some of them have been postulated as significant in the pathogenesis of pregnancy complications like GDM. This report aims to review some of the recent topics of adipokine research that may be of particular importance in patho-physiology and diagnosis of gestational diabetes mellitus. Because of manuscript length limitations, after thorough literature review and in view of the recent evidence, we focus on the one of the most well-known adipokine: adiponectin, and not so well-studied: nesfatin-1, chemerin, ghrelin, and CTRP 1.
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7.
A minireview of E4BP4/NFIL3 in heart failure.
Velmurugan, BK, Chang, RL, Marthandam Asokan, S, Chang, CF, Day, CH, Lin, YM, Lin, YC, Kuo, WW, Huang, CY
Journal of cellular physiology. 2018;(11):8458-8466
Abstract
Heart failure (HF) remains a major cause of morbidity and mortality worldwide. The primary cause identified for HF is impaired left ventricular myocardial function, and clinical manifestations may lead to severe conditions like pulmonary congestion, splanchnic congestion, and peripheral edema. Development of new therapeutic strategies remains the need of the hour for controlling the problem of HF worldwide. Deeper insights into the molecular mechanisms involved in etiopathology of HF indicate the significant role of calcium signaling, autocrine signaling pathways, and insulin-like growth factor-1 signaling that regulates the physiologic functions of heart growth and development such as contraction, metabolism, hypertrophy, cytokine signaling, and apoptosis. In view of these facts, a transcription factor (TF) regulating the myriad of these signaling pathways may prove as a lead candidate for development of therapeutics. Adenovirus E4 promoter-binding protein (E4BP4), also known as nuclear-factor, interleukin 3 regulated (NFIL3), a type of basic leucine zipper TF, is known to regulate the signaling processes involved in the functioning of heart. The current review discusses about the expression, structure, and functional role of E4BP4 in signaling processes with emphasis on calcium signaling mechanisms, autocrine signaling, and insulin-like growth factor II receptor-mediated processes regulated by E4BP4 that may regulate the pathogenesis of HF. We propose that E4BP4, being the critical component for the regulation of the above signaling processes, may serve as a novel therapeutic target for HF, and scientific investigations are merited in this direction.
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8.
Targeting ZBP-89 for the treatment of hepatocellular carcinoma.
Wang, N, Wang, S, Yang, SL, Liu, LP, Li, MY, Lai, PBS, Chen, GG
Expert opinion on therapeutic targets. 2018;(10):817-822
Abstract
Zinc-binding protein-89 (ZBP-89) is a Krüppel-type zinc-finger transcription factor that regulates target gene expression profiles via directly binding to GC-rich gene promoters, recruiting chromatin modifiers or by interacting with other proteins. The importance of ZBP-89 in the regulation of cell cycle arrest and apoptosis has led to increased interest and investigations for its role in cancer development. Areas covered: We describe ZBP-89 as a candidate therapeutic target for hepatocellular carcinoma (HCC) from several perspectives. ZBP-89 can upregulate apoptosis in HCC in a p53-dependent or - independent manner. In addition, the negative regulation of ZBP-89 on liver cancer stemness sheds light on its possible effect on sensitizing HCC to chemotherapies and the reduction of HCC relapse. The prognostic significance of ZBP-89 in HCC patients further suggests its clinical importance as a potential tumor suppressor. Expert opinion: Given the roles of ZBP-89 in HCC, we believe, ZBP-89 is a promising therapeutic target for enhancing apoptosis and diminishing the liver cancer stemness. At the same time, we also face a series of challenges, especially in the clinical implication of ZBP-89. Resolving the current controversies will advance the development of ZBP-89 for anti-HCC therapy.
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9.
CIN-TCP transcription factors: Transiting cell proliferation in plants.
Sarvepalli, K, Nath, U
IUBMB life. 2018;(8):718-731
Abstract
Leaves are the most conspicuous planar organs in plants, designed for efficient capture of sunlight and its conversion to energy that is channeled into sustaining the entire biosphere. How a few founder cells derived from the shoot apical meristem give rise to diverse leaf forms has interested naturalists and developmental biologists alike. At the heart of leaf morphogenesis lie two simple cellular processes, division and expansion, that are spatially and temporally segregated in a developing leaf. In leaves of dicot model species, cell division occurs predominantly at the base, concomitant with the expansion and differentiation of cells at the tip of the lamina that drives increase in leaf surface area. The timing of the transition from one cell fate (division) to the other (expansion) within a growing leaf lamina is a critical determinant of final leaf shape, size, complexity and flatness. The TCP proteins, unique to plant kingdom, are sequence-specific DNA-binding transcription factors that control several developmental and physiological traits. A sub-group of class II TCPs, called CINCINNATA-like TCPs (CIN-TCPs henceforth), are key regulators of the timing of the transition from division to expansion in dicot leaves. The current review highlights recent advances in our understanding of how the pattern of CIN-TCP activity is translated to the dynamic spatio-temporal control of cell-fate transition through the transactivation of cell-cycle regulators, growth-repressing microRNAs, and interactions with the chromatin remodeling machinery to modulate phytohormone responses. Unravelling how environmental inputs influence CIN-TCP-mediated growth control is a challenge for future studies. © 2018 IUBMB Life, 70(8):718-731, 2018.
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10.
Novel transmitters in brain stem vagal neurocircuitry: new players on the pitch.
Bülbül, M, Travagli, RA
American journal of physiology. Gastrointestinal and liver physiology. 2018;(1):G20-G26
Abstract
The last few decades have seen a major increase in the number of neurotransmitters and neuropeptides recognized as playing a role in brain stem neurocircuits, including those involved in homeostatic functions such as stress responsiveness, gastrointestinal motility, feeding, and/or arousal/wakefulness. This minireview will focus on the known physiological role of three of these novel neuropeptides, i.e., apelin, nesfatin-1, and neuropeptide-S, with a special emphasis on their hypothetical roles in vagal signaling related to gastrointestinal motor functions.