scholarly journals Studies on C. elegans probed with estradiol, elucidate the critical role of Na+/H+ exchanger, nhx-2 in reproductive senescence and neuronal health

2020 ◽  
Author(s):  
Shikha Shukla ◽  
Lalit Kumar ◽  
Arunabh Sarkar ◽  
Kottapalli Srividya ◽  
Aamir Nazir
Keyword(s):  
Dietary Restriction ◽  
Histone H3 ◽  
Alpha Synuclein ◽  
Lysine Methylation ◽  
Estradiol Treatment ◽  
Reproductive Senescence ◽  
C Elegans ◽  
Histone H3 Acetylation ◽  
Alpha Synuclein Aggregation ◽  
H3 Acetylation

AbstractSetting in of reproductive senescence (RS) gives rise to several changes, making aged individuals susceptible to neurodegenerative diseases, cardiovascular and bone disorders amongst others. The present study deciphers the association of reproductive senescence, presence/absence of the sex hormone estradiol with age-associated neurodegenerative diseases. We employed RNAi induced silencing of a subset of 22 genes that are known to delay RS, followed by studies on alpha-Synuclein aggregation and associated effects in the transgenic C. elegans. These studies led us to fuctional characterisation of the Na+/H+ exchanger, expressed exclusively in gut. We found that RNAi of nhx-2 ameliorates the affects associated with alpha-Synuclein aggregation via mimicking dietary restriction as it alters food absorption from the gut. Our studies further elucidated that such effects are Sir-2.1 driven as nhx-2 RNAi did not delay reproductive senescence when sir-2.1 was silenced concurrently. As estradiol plays a central role in both reproductive health as well as neuronal health, we performed structural binding analysis that demonstrated the binding potential of the estradiol receptor NHR-14 with nhx-2 gene. Hence, we treated the worms with estradiol and observed that the transcription levels of nhx-2 were elevated above the endogenous level. To unravel the underlying molecular mechanism of induction we performed ChIP analysis and it revealed that estradiol treatment gives rise to enhanced NHX-2 levels through inducing the promoter specific histone H3 acetylation (H3K9) and lysine methylation (H3K4me3).Graphical abstractHIGHLIGHTSSilencing of a sodium proton antiporter nhx-2 of gut ameliorates effects associated with alpha-Synuclein aggregation via mimicking dietary restriction in C. elegans.We have established a genetic cross to construct a strain that expresses mCherry SIR-2.1 ubiquitously and α-Synuclein in muscles, that assists in corroborating the link between NHX-2 and SIR-2.1.Human 17-β-Estradiol treatment induces the expression of nhx-2, through inducing the promoter specific histone H3 acetylation (H3K9) and lysine methylation (H3K4me3).Effects associated with nhx-2, including prolonged reproductive span and neuroprotective effects, are SIR-2.1 driven.nhx-2 silencing decreases alpha-Synuclein aggregation however estradiol mediated overexpression above the endogenus level, does not amend the aggregation any further.

Targeted Downregulation of Estradiol Binding Na+/H+ Exchanger Nhx-2, Mimics Calorie Restriction, Extends Reproductive Longevity and Ameliorates Effects Associated With Alpha Synuclein Aggregation In C. Elegans

2021 ◽  
Author(s):  
Shikha Shukla ◽  
Lalit Kumar ◽  
Arunabh Sarkar ◽  
Kottapalli Srivi ◽  
Aamir Nazir
Keyword(s):  
Reproductive Health ◽  
Neurodegenerative Diseases ◽  
Functional Characterization ◽  
Alpha Synuclein ◽  
Binding Potential ◽  
Estradiol Treatment ◽  
Reproductive Senescence ◽  
Knock Out ◽  
C Elegans ◽  
Alpha Synuclein Aggregation

Abstract Setting in of reproductive senescence (RS) gives rise to several changes, making aged individuals susceptible to multiple disorders including neurodegenerative diseases, cardiovascular ailments and bone disorders amongst others. The present study, employing transgenic C. elegans that expresses ‘human’ alpha synuclein, endeavors to decipher the association of reproductive senescence with age-associated neurodegenerative diseases and behavioral ageing, under normal conditions and after being probed with estradiol. We carried out RNAi induced silencing of a subset of 22 genes that are known to delay RS, followed by studies on alpha-Synuclein aggregation and associated effects. These studies led us to functional characterization of the Na+/H+ exchanger; nhx-2, expressed exclusively in gut. We found that RNAi of nhx-2 not only ameliorates the effects associated with alpha-Synuclein aggregation, but it also attunes effects related to behavioral aging including that of reproductive health-span and neuroprotection via mimicking dietary restriction, as it alters food absorption from the gut. We further elucidated that these effects are Sir-2.1 driven as nhx-2 knock out did not delay reproductive senescence in knock down condition of sir-2.1. To substantiate our findings, we performed whole transcriptome analysis in nhx-2 mutant strain. Our data revealed differential expression of 61 out of 62 hallmark genes of CR described by GenDR, in knock out condition of nhx-2. As estradiol plays a central role in both reproductive health as well as neuronal health, we subjected worms to exogenous estradiol treatment and observed that it led to elevated levels of nhx-2. Studies on structural binding analysis demonstrated significant binding potential of estradiol receptor NHR-14 with nhx-2 gene and ChIP analysis revealed that estradiol treatment gives rise to enhanced NHX-2 levels through inducing the promoter specific histone H3 acetylation (H3K9) and lysine methylation (H3K4me3). These studies identify nhx-2 as an important modulator that extends reproductive longevity and ameliorates effects associated with alpha synuclein aggregation in C elegans.

scholarly journals Butyrate Stimulates Histone H3 Acetylation, 8-Isoprostane Production, RANKL Expression, and Regulated Osteoprotegerin Expression/Secretion in MG-63 Osteoblastic Cells

2018 ◽  
Vol 19 (12) ◽  
pp. 4071 ◽  
Author(s):  
Mei-Chi Chang ◽  
Yunn-Jy Chen ◽  
Yun-Chia Lian ◽  
Bei-En Chang ◽  
Chih-Chia Huang ◽  
...  
Keyword(s):  
Protein Expression ◽  
Cell Viability ◽  
Butyric Acid ◽  
Root Canal ◽  
Histone H3 ◽  
Rankl Expression ◽  
Alp Activity ◽  
Histone H3 Acetylation ◽  
Apoptosis And Necrosis ◽  
H3 Acetylation

Butyric acid as a histone deacetylase (HDAC) inhibitor is produced by a number of periodontal and root canal microorganisms (such as Porphyromonas, Fusobacterium, etc.). Butyric acid may affect the biological activities of periodontal/periapical cells such as osteoblasts, periodontal ligament cells, etc., and thus affect periodontal/periapical tissue destruction and healing. The purposes of this study were to study the toxic effects of butyrate on the matrix and mineralization marker expression in MG-63 osteoblasts. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cellular apoptosis and necrosis were analyzed by propidium iodide/annexin V flow cytometry. The protein and mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). OPG, soluble RANKL (sRANKL), 8-isoprostane, pro-collagen I, matrix metalloproteinase-2 (MMP-2), osteonectin (SPARC), osteocalcin and osteopontin (OPN) secretion into culture medium were measured by enzyme-linked immunosorbant assay. Alkaline phosphatase (ALP) activity was checked by ALP staining. Histone H3 acetylation levels were evaluated by immunofluorescent staining (IF) and Western blot. We found that butyrate activated the histone H3 acetylation of MG-63 cells. Exposure of MG-63 cells to butyrate partly decreased cell viability with no marked increase in apoptosis and necrosis. Twenty-four hours of exposure to butyrate stimulated RANKL protein expression, whereas it inhibited OPG protein expression. Butyrate also inhibited the secretion of OPG in MG-63 cells, whereas the sRANKL level was below the detection limit. However, 3 days of exposure to butyrate (1 to 8 mM) or other HDAC inhibitors such as phenylbutyrate, valproic acid and trichostatin stimulated OPG secretion. Butyrate stimulated 8-isoprostane, MMP-2 and OPN secretion, but not procollagen I, or osteocalcin in MG-63 cells. Exposure to butyrate (2–4 mM) for 3 days markedly stimulated osteonectin secretion and ALP activity. In conclusion, higher concentrations of butyric acid generated by periodontal and root canal microorganisms may potentially induce bone destruction and impair bone repair by the alteration of OPG/RANKL expression/secretion, 8-isoprostane, MMP-2 and OPN secretion, and affect cell viability. However, lower concentrations of butyrate (1–4 mM) may stimulate ALP, osteonectin and OPG. These effects are possibly related to increased histone acetylation. These events are important in the pathogenesis and repair of periodontal and periapical destruction.

scholarly journals Sgf29 binds histone H3K4me2/3 and is required for SAGA complex recruitment and histone H3 acetylation

2011 ◽  
Vol 30 (14) ◽  
pp. 2829-2842 ◽  
Author(s):  
Chuanbing Bian ◽  
Chao Xu ◽  
Jianbin Ruan ◽  
Kenneth K Lee ◽  
Tara L Burke ◽  
...  
Keyword(s):  
Histone H3 ◽  
Saga Complex ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

scholarly journals Promoter-specific changes in initiation, elongation and homeostasis of histone H3 acetylation during CBP/p300 inhibition

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Emily Hsu ◽  
Nathan R Zemke ◽  
Arnold J Berk
Keyword(s):  
Rna Polymerase Ii ◽  
Control Point ◽  
Histone H3 ◽  
Airway Epithelial Cells ◽  
Proximal Region ◽  
Transferase Activity ◽  
Transcriptional Elongation ◽  
Elongation Complex ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

Regulation of RNA Polymerase II (Pol2) elongation in the promoter proximal region is an important and ubiquitous control point for gene expression in metazoans. We report that transcription of the adenovirus 5 E4 region is regulated during the release of paused Pol2 into productive elongation by recruitment of the super elongation complex (SEC), dependent on promoter H3K18/27 acetylation by CBP/p300. We also establish that this is a general transcriptional regulatory mechanism that applies to ~6% of expressed protein-coding genes in primary human airway epithelial cells. We observed that a homeostatic mechanism maintains promoter, but not enhancer H3K18/27ac in response to extensive inhibition of CBP/p300 acetyl transferase activity by the highly specific small molecule inhibitor A-485. Further, our results suggest a function for BRD4 association at enhancers in regulating paused Pol2 release at nearby promoters. Taken together, our results uncover processes regulating transcriptional elongation by promoter region histone H3 acetylation and homeostatic maintenance of promoter, but not enhancer, H3K18/27ac in response to inhibition of CBP/p300 acetyl transferase activity.

scholarly journals Interplay between Chromatin and trans-Acting Factors on the IME2 Promoter upon Induction of the Gene at the Onset of Meiosis

2006 ◽  
Vol 27 (4) ◽  
pp. 1254-1263 ◽  
Author(s):  
Tomomi Inai ◽  
Masashi Yukawa ◽  
Eiko Tsuchiya
Keyword(s):  
Histone Deacetylase ◽  
Chromatin Structure ◽  
Molecular Basis ◽  
Histone Acetyltransferase ◽  
Histone H3 ◽  
Repressive Chromatin ◽  
Tata Element ◽  
Histone H3 Acetylation ◽  
Low Levels ◽  
H3 Acetylation

ABSTRACT The IME2 gene is one of the key regulators of the initiation of meiosis in budding yeast. This gene is repressed during mitosis through the repressive chromatin structure at the promoter, which is maintained by the Rpd3-Sin3 histone deacetylase (HDAC) complex. IME2 expression in meiosis requires Gcn5/histone acetyltransferase, the transcriptional activator Ime1, and the chromatin remodeler RSC; however, the molecular basis of IME2 activation had not been previously defined. We found that, during mitotic growth, a nucleosome masked the TATA element of IME2, and this positioning depended on HDAC. This chromatin structure was remodeled at meiosis by RSC that was recruited to TATA by Ime1. Stable tethering of Ime1 to the promoter required the presence of Gcn5. Interestingly, Ime1 binding to the promoter was kept at low levels during the very early stages in meiosis, even when the levels of Ime1 and histone H3 acetylation at the promoter were at their highest, making a 4- to 6-h delay of the IME2 expression from that of IME1. HDAC was continuously present at the promoter regardless of the transcriptional condition of IME2, and deletion of RPD3 allowed the IME2 expression shortly after the expression of IME1, suggesting that HDAC plays a role in regulating the timing of IME2 expression.

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