scholarly journals Effects of gypenosides on enteroendocrine L-cell function and GLP-1 secretion

2020 ◽  
Author(s):  
Chinmai Patibandla ◽  
Erin Campbell ◽  
Xinhua Shu ◽  
Angus M Shaw ◽  
Sharron Dolan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Function ◽  
Postprandial Glucose ◽  
Prohormone Convertase ◽  
Antioxidant Gene ◽  
Protein Levels ◽  
L Cells ◽  
Prohormone Convertase 2

AbstractGlucagon-like peptide 1 (GLP-1) is an incretin hormone produced in gut L-cells, which regulates postprandial glucose-dependent insulin secretion, also known as the incretin effect. GLP-1 secretion may be reduced in type 2 diabetes mellitus, impacting on glycaemic regulation. Thus, methods to enhance endogenous GLP-1 secretion by use of natural GLP-1 secretagogues may improve glucose control in diabetes. Gypenosides (GYP) extracted from the plant Gynostemma Pentaphyllum (Jiaogulan) are known for their glucose-lowering effects both in vitro and in vivo, although their effect on GLP-1 secretion is unknown. Our results showed that GYP enhanced cell viability and significantly upregulated antioxidant gene Nrf2, Cat and Ho-1 expression. GYP did not affect glucokinase expression but downregulated proglucagon gene expression over 24h, although, cellular GLP-1 content was unchanged. Prohormone convertase 1 (Pcsk1) gene expression was unchanged by GYP over 24h, although protein levels were significantly downregulated, while prohormone convertase 2 (Pcsk2) mRNA and protein levels were significantly upregulated. Acute exposure to gypenosides enhanced calcium uptake and GLP-1 release from GLUTag cells both at low and high glucose concentrations. These results suggest that anti-diabetic properties of gypenosides are partly linked to their ability to stimulate GLP-1 secretion. Gypenosides enhance antioxidant gene expression and may protect L-cells from excess oxidative stress.

scholarly journals Helicases FANCJ, RTEL1 and BLM Act on Guanine Quadruplex DNA in Vivo

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 870 ◽  
Author(s):  
Peter Lansdorp ◽  
Niek van Wietmarschen
Keyword(s):  
Gene Expression ◽  
Genome Stability ◽  
Cell Function ◽  
Historical Context ◽  
Telomere Maintenance ◽  
Dna Structures ◽  
G4 Dna ◽  
Guanine Quadruplex

Guanine quadruplex (G4) structures are among the most stable secondary DNA structures that can form in vitro, and evidence for their existence in vivo has been steadily accumulating. Originally described mainly for their deleterious effects on genome stability, more recent research has focused on (potential) functions of G4 structures in telomere maintenance, gene expression, and other cellular processes. The combined research on G4 structures has revealed that properly regulating G4 DNA structures in cells is important to prevent genome instability and disruption of normal cell function. In this short review we provide some background and historical context of our work resulting in the identification of FANCJ, RTEL1 and BLM as helicases that act on G4 structures in vivo. Taken together these studies highlight important roles of different G4 DNA structures and specific G4 helicases at selected genomic locations and telomeres in regulating gene expression and maintaining genome stability.

255 THE ESTROGENIC EVALUATION OF PARABENS USING RAT UTERINE CALBINDIN-D9k

2010 ◽  
Vol 22 (1) ◽  
pp. 285
Author(s):  
T. T. B. Vo ◽  
E. B. Jeung
Keyword(s):  
Gene Expression ◽  
Adverse Effects ◽  
Treated Group ◽  
Environmental Chemicals ◽  
Female Rats ◽  
Protein Levels ◽  
Calbindin D9k ◽  
The Difference

In the current study, calbindin-D9k (CaBP-9k), a potent biomarker for screening estrogen-like environmental chemicals in vivo and in vitro, was adopted to examine the potential estrogen-like property of the following parabens: propyl-, isopropyl-, butyl-, and isobutyl-paraben. Immature female rats were administered for 3 days from postnatal day 14 to 16 with 17?-ethinylestradiol (EE, 1 mg/kg of body weight (BW) per day) or parabens (62.5, 250, and 1000 mg/kg of BW per day). In uterotrophic assays, significantly increased uterus weights were detected in the EE-treated group and in the groups treated with the greatest dose of isopropyl-, butyl- and isobutyl-paraben. In addition, these parabens induced uterine CaBP-9k mRNA and protein levels, whereas co-treatment of parabens and fulvestrant (Faslodex, formerly known as ICI 182, 780), a pure estrogen receptor (ER) antagonist, completely reversed the paraben-induced gene expression and increased uterine weights. To investigate the ER-mediated mechanism(s) by which parabens exert their effects, the expression level of ERα and progesterone receptor (PR) was analyzed. Exposure to EE or parabens caused a dramatic decrease in expression of both ER? mRNA and protein levels, whereas co-treatment with fulvestrant reversed these effects. These data showed the difference of CaBP-9k and ER? expression, suggesting that CaBP-9k might not express via ER? pathway. In the effect of parabens on CaBP-9k expression through PR mediation, a significantly increased expression of uterine PR gene, a well-known ER regulating gene, at both transcriptional and translational levels was indicated in the greatest dose of isopropyl- and butyl-paraben. These parabens induced PR gene expression that was completely blocked by fulvestrant. This result indicates that CaBP-9k expression might involve PR mediates in the estrogenic effect of paraben in immature rat uteri. Taken together, parabens exhibited an estrogen-like property in vivo, which might be mediated by a PR and/or ER? signaling pathway. In addition, our results expanded the current understanding of the potential adverse effects of parabens associated with their estrogen-like activities. Further investigation is needed to elucidate in greater detail the adverse effects of parabens in humans and wildlife.

scholarly journals Evaluation of Lentiviral-Mediated Expression of Sodium Iodide Symporter in Anaplastic Thyroid Cancer and the Efficacy of In Vivo Imaging and Therapy

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Chien-Chih Ke ◽  
Ya-Ju Hsieh ◽  
Luen Hwu ◽  
Fu-Hui Wang ◽  
Fu-Du Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sodium Iodide ◽  
Cell Function ◽  
Tumor Imaging ◽  
Promising Result ◽  
Anaplastic Thyroid Cancer ◽  
Anaplastic Thyroid Carcinoma ◽  
Sodium Iodide Symporter

Anaplastic thyroid carcinoma (ATC) is one of the most deadly cancers. With intensive multimodalities of treatment, the survival remains low. ATC is not sensitive to131I therapy due to loss of sodium iodide symporter (NIS) gene expression. We have previously generated a stable human NIS-expressing ATC cell line, ARO, and the ability of iodide accumulation was restored. To make NIS-mediated gene therapy more applicable, this study aimed to establish a lentiviral system for transferring hNIS gene to cells and to evaluate the efficacy of in vitro and in vivo radioiodide accumulation for imaging and therapy. Lentivirus containing hNIS cDNA were produced to transduce ARO cells which do not concentrate iodide. Gene expression, cell function, radioiodide imaging and treatment were evaluated in vitro and in vivo. Results showed that the transduced cells were restored to express hNIS and accumulated higher amount of radioiodide than parental cells. Therapeutic dose of131I effectively inhibited the tumor growth derived from transduced cells as compared to saline-treated mice. Our results suggest that the lentiviral system efficiently transferred and expressed hNIS gene in ATC cells. The transduced cells showed a promising result of tumor imaging and therapy.

scholarly journals Investigation of exposure to lifestyle and environmental factors on cumulus-oocyte complex function

2021 ◽  
Author(s):  
◽  
Kelly Anne Campen
Keyword(s):  
Gene Expression ◽  
Oocyte Quality ◽  
Protein Levels ◽  
Time Interaction ◽  
Cumulus Oocyte Complex ◽  
In Vitro Exposure ◽  
In Vitro Effects ◽  
In Vivo Effects

<p>Pathways involved in bi-directional communication within the cumulus-oocyte complex (COC) include gap junction (GJ) communication, oocyte growth factor production, and glucose metabolism and are essential for oocyte health. Perturbation of these pathways may result in reduced oocyte quality due to altered COC function. Using rats as a model, in vitro effects of exposure to bisphenol A (BPA), caffeine, nicotine, ethanol, methylenedioxymeth- amphetamine (MDMA), or Δ⁹-tetrahydrocannabinol (THC) on COC function were investigated. Furthermore, MDMA was administered to rats to compare in vitro with in vivo effects.  The transfer of a fluorescent dye (calcein) from cumulus cells (CC) to the oocyte was used as a measure of GJ communication. Expression of CC-derived (Atr, Cx43, Cycs, Gfpt1, Pfkp) and oocyte-derived (Atr, Bmp15, Cx37, Gdf9) genes were measured using multiplex TaqMan quantitative PCR. Levels of CX43 and GDF9 proteins were quantified using Western blotting.  Optimisation of the GJ bioassay included the addition of phosphodiesterase inhibitors (rolipram and dipyridamole), and a 1 hour post-calcein incubation period to allow dye transfer. Quantification of gene expression in calcein-treated CC and oocytes was validated, enabling direct comparisons between GJ communication and gene expression.  To determine the in vitro effects, COC were incubated with test factors at high physiological concentrations over 25 hours. GJ communication decreased over time in control COC. This reduction was attenuated after exposure to BPA and nicotine, and partially by caffeine. Furthermore, exposure to ethanol maintained oocyte meiotic arrest, whereas MDMA and THC promoted meiotic resumption.  Oocyte-derived gene expression was mostly unaffected by in vitro exposure to the lifestyle and environmental factors, although a treatment x time interaction for Cx37 levels following nicotine exposure was observed. Of the CC-derived genes, Cx43 was the most sensitive where BPA, MDMA, and THC increased, and caffeine and ethanol decreased, expression. In CC, exposure to MDMA and THC increased Gfpt1 levels and exposure to MDMA resulted in a treatment x time interaction in Cycs and Pfkp expression.  In COC, caffeine increased CX43 protein levels after 1 hour. Nicotine initially reduced, but with time increased CX43 levels. Furthermore, CX43 levels decreased and increased after 25 hour exposures to ethanol and MDMA, respectively. GDF9 protein levels in COC exhibited wide within-treatment variation. Overall, BPA and caffeine reduced GDF9 levels after 1 hour whereas GDF9 levels were increased following exposure to BPA, caffeine, MDMA, and THC for 25 hours.  To determine in vivo effects, female rats were administered saline or 5 mg/kg/day MDMA for 3 days. COC from MDMA-treated rats had higher levels of CX43 protein but gene expression and meiotic reactivation were unaffected.  In conclusion, COC function was altered by in vitro exposure to BPA, caffeine, ethanol, nicotine, MDMA, and THC. Furthermore, in vivo exposure to MDMA elicits similar, albeit reduced, effects on COC function. A role for CC in protecting the oocyte from harmful contaminants is proposed. Perturbation of the bi-directional communication pathway is likely to influence oocyte quality due to alterations in nutrient availability and timing of follicular events, although these may not be associated with negative outcomes. This study provides evidence that exposure to lifestyle factors and environmental contaminants affect COC function.</p>

scholarly journals Satellite cell-mediated angiogenesis in vitro coincides with a functional hypoxia-inducible factor pathway

2009 ◽  
Vol 296 (6) ◽  
pp. C1321-C1328 ◽  
Author(s):  
R. P. Rhoads ◽  
R. M. Johnson ◽  
C. R. Rathbone ◽  
X. Liu ◽  
C. Temm-Grove ◽  
...  
Keyword(s):  
Gene Expression ◽  
Satellite Cell ◽  
Hypoxia Inducible Factor ◽  
Collagen Gel ◽  
Culture Conditions ◽  
Cell Physiology ◽  
Vegf Gene ◽  
Protein Levels

Muscle regeneration involves the coordination of myogenesis and revascularization to restore proper muscle function. Myogenesis is driven by resident stem cells termed satellite cells (SC), whereas angiogenesis arises from endothelial cells and perivascular cells of preexisting vascular segments and the collateral vasculature. Communication between myogenic and angiogenic cells seems plausible, especially given the number of growth factors produced by SC. To characterize these interactions, we developed an in vitro coculture model composed of rat skeletal muscle SC and microvascular fragments (MVF). In this system, isolated epididymal MVF suspended in collagen gel are cultured over a rat SC monolayer culture. In the presence of SC, MVF exhibit greater indices of angiogenesis than MVF cultured alone. A positive dose-dependent effect of SC conditioned medium (CM) on MVF growth was observed, suggesting that SC secrete soluble-acting growth factor(s). Next, we specifically blocked VEGF action in SC CM, and this was sufficient to abolish satellite cell-induced angiogenesis. Finally, hypoxia-inducible factor-1α (HIF-1α), a transcriptional regulator of VEGF gene expression, was found to be expressed in cultured SC and in putative SC in sections of in vivo stretch-injured rat muscle. Hypoxic culture conditions increased SC HIF-1α activity, which was positively associated with SC VEGF gene expression and protein levels. Collectively, these initial observations suggest that a heretofore unexplored aspect of satellite cell physiology is the initiation of a proangiogenic program.

Transketolase Activity but not Thiamine Membrane Transport Change in Response to Hyperglycaemia and Kidney Dysfunction

2017 ◽  
Vol 126 (04) ◽  
pp. 255-262 ◽  
Author(s):  
Katarína Chalásová ◽  
Lukáš Pácal ◽  
Anna Pleskačová ◽  
Lucia Knopfová ◽  
Jitka Řehořová ◽  
...  
Keyword(s):  
Gene Expression ◽  
Kidney Disease ◽  
Pentose Phosphate ◽  
Protective Mechanism ◽  
Protein Levels ◽  
Human Experiments ◽  
Key Enzyme ◽  
Vitro Analysis

Abstract Aim Pentose phosphate pathway (PPP) with key enzyme transketolase (TKT), represents a potentially ‘protective’ mechanism in hyperglycaemia. Diabetic kidney disease (DKD), a common complication of both type 1 and type 2 diabetes associated with significant morbidity and mortality, represents the most common cause of chronic kidney disease (CKD). We hypothesized that protective PPP action in diabetes and eventually even more severely in concomitant DKD might be compromised by limited intracellular availability of an active TKT cofactor thiamine diphosphate (TDP). Methods Effect of hyperglycaemia on gene expression and protein levels of key PPP loci was studied in vitro using human cell lines relevant to diabetes (HUVEC and HRGEC) and (together with measurement of TKT activity, plasma thiamine and erythrocyte TDP concentration) in vivo in diabetic vs. non-diabetic subjects with comparable renal function (n=83 in total). Results Hyperglycaemia significantly decreased protein levels of RFC-1, THTR1, THTR2 and TKT (P<0.05) in vitro. Analysis of blood samples from CKD patients with and without diabetes and from controls did not reveal any difference in gene expression and protein levels of thiamine transporters while TKT activity and TDP in erythrocytes gradually increased with decreasing kidney function being highest in patients with CKD3-4 of both diabetic and non-diabetic aetiology. Hyperglycaemia and uremic serum mimicking CKD in diabetes did not affect TKT activity in vitro (P<0.05). Conclusion Both in vitro and human experiments showed decrease or unchanged expression, respectively, of thiamine transporters induced by hyperglycaemia while TKT activity in parallel with intracellular TDP was increased in CKD patients with or without diabetes. Therefore, lack of adaptive increase of thiamine transmembrane transport allowing further increase of TKT activity might contribute to compromised PPP function in diabetes and CKD and to the development of glycotoxic injury.

Transcriptional regulation of pulmonary elastin gene expression in elastase-induced injury

2003 ◽  
Vol 285 (2) ◽  
pp. L354-L362 ◽  
Author(s):  
Celeste B. Rich ◽  
Isabel Carreras ◽  
Edgar C. Lucey ◽  
Julie A. Jaworski ◽  
Jo Ann Buczek-Thomas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tissue Injury ◽  
Gene Promoter ◽  
Activity Levels ◽  
Intratracheal Administration ◽  
Protein Levels ◽  
Elastin Gene ◽  
Pulmonary Fibroblast

Previously we have shown that treatment of confluent, pulmonary fibroblast cultures with elastase results in upregulation of elastin mRNA and protein levels. In the present study we focused on determining the level at which elastin expression is upregulated after elastase exposure. We examined as models for this investigation elastin gene expression in primary pulmonary fibroblast cells during the transition from subconfluent to confluent cultures and in confluent, matrix-laden cultures treated briefly with elastase. In addition, we extended our studies to mice that were given an intratracheal dose of elastase; the effects on lung elastin mRNA and elastin promoter activity levels were measured and compared with results from in vitro cell models. The results demonstrate that upregulation of elastin gene expression during the transition of subconfluent to confluent cultures and after elastase injury is associated with an increase in the level of transcription both in vitro and in vivo. Furthermore, intratracheal administration of elastase to transgenic mice illustrates that the increased levels of elastin mRNA are accompanied by increased activity of the elastin gene promoter in cells spatially positioned near major sites of tissue injury.

scholarly journals miR-29a and miR-30c negatively regulate DNMT 3a in cardiac ischemic tissues: implications for cardiac remodelling

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Carolina Gambacciani ◽  
Claudia Kusmic ◽  
Elena Chiavacci ◽  
Francesco Meghini ◽  
Milena Rizzo ◽  
...  
Keyword(s):  
Gene Expression ◽  
De Novo ◽  
Ischemia Reperfusion ◽  
Chromatin Accessibility ◽  
Response To Therapy ◽  
Vitro Assay ◽  
Protein Levels ◽  
Transcriptional Reprogramming

AbstractRecent evidences indicate that epigenetic changes play an important role in the transcriptional reprogramming of gene expression that characterizes cardiac hypertrophy and failure and may dictate response to therapy. Several data demonstrate that microRNAs (miRNAs) play critical roles both in normal cardiac function and under pathological conditions. Here we assessed, in in vivo rat models of myocardial infarction (MI) and ischemia-reperfusion (IR), the relationship between two miRNAs (miR-29a and miR-30c) and de novo methyltransferase (DNMT3a) which, altering the chromatin accessibility for transcription factors, deeply impacts gene expression. We showed that the levels of members of miR-29 and miR- 30 families were down regulated in ischemic tissues whilst the protein levels of DNMT3a were increased, such a relation was not present in healthy tissues. Furthermore, by an in vitro assay, we demonstrated that both miRNAs are able to down regulate DNMT3a by directly interacting with DNMT3a 3’UTR and that miR-29a or miR-30c overexpression in the cardiac HL1 cell line causes decrease of DNMT3a enzyme both at the mRNA and protein levels. Our data, besides confirming the down regulation of the miR-29a and miR-30c in infarcted tissues, envisage a cross-talk between microRNAs and chromatin modifying enzymes suggesting a new mechanism that might generate the alterations of DNA methylation often observed in myocardial pathophysiology.

Growth hormone-induced STAT5B regulates Star gene expression through a cooperation with cJUN in mouse MA-10 Leydig cells

Endocrinology ◽  
2021 ◽  
Author(s):  
Pierre-Olivier Hébert-Mercier ◽  
Francis Bergeron ◽  
Nicholas M Robert ◽  
Samir Mehanovic ◽  
Kenley Joule Pierre ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Hormone ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Cell Function ◽  
Mrna Levels ◽  
Leydig Cell Function ◽  
Star Gene

Abstract Leydig cells produce androgens that are essential for male sex differentiation and reproductive function. Leydig cell function is regulated by several hormones and signaling molecules, including growth hormone (GH). Although GH is known to upregulate Star gene expression in Leydig cells, its molecular mechanism of action remains unknown. The STAT5B transcription factor is a downstream effector of GH signaling in other systems. While STAT5B is present in both primary and Leydig cell lines, its function in these cells has yet to be ascertained. Here we report that treatment of MA-10 Leydig cells with GH or overexpression of STAT5B induces Star mRNA levels and increases steroid hormone output. The mouse Star promoter contains a consensus STAT5B element (TTCnnnGAA) at -756 bp to which STAT5B binds in vitro (EMSA and supershift) and in vivo (ChIP) in a GH-induced manner. In functional promoter assays, STAT5B was found to activate a -980 bp mouse Star reporter. Mutating the -756 bp element prevented STAT5B binding but did not abrogate STAT5B-responsiveness. STAT5B was found to functionally cooperate with DNA-bound cJUN. The STAT5B/cJUN cooperation was only observed in Leydig cells and not in Sertoli or fibroblast cells, indicating that additional Leydig cell-enriched transcription factors are required. The STAT5B/cJUN cooperation was lost only when both STAT5B and cJUN elements were mutated. In addition to identifying the Star gene as a novel target for STAT5B in Leydig cells, our data provide important new insights into the mechanism of GH and STAT5B action in the regulation of Leydig cell function.

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