scholarly journals Blood phenylalanine reduction reverses gene expression changes observed in a mouse model of phenylketonuria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachna Manek ◽  
Yao V. Zhang ◽  
Patricia Berthelette ◽  
Mahmud Hossain ◽  
Cathleen S. Cornell ◽  
...  

AbstractPhenylketonuria (PKU) is a genetic deficiency of phenylalanine hydroxylase (PAH) in liver resulting in blood phenylalanine (Phe) elevation and neurotoxicity. A pegylated phenylalanine ammonia lyase (PEG-PAL) metabolizing Phe into cinnamic acid was recently approved as treatment for PKU patients. A potentially one-time rAAV-based delivery of PAH gene into liver to convert Phe into tyrosine (Tyr), a normal way of Phe metabolism, has now also entered the clinic. To understand differences between these two Phe lowering strategies, we evaluated PAH and PAL expression in livers of PAHenu2 mice on brain and liver functions. Both lowered brain Phe and increased neurotransmitter levels and corrected animal behavior. However, PAL delivery required dose optimization, did not elevate brain Tyr levels and resulted in an immune response. The effect of hyperphenylalanemia on liver functions in PKU mice was assessed by transcriptome and proteomic analyses. We observed an elevation in Cyp4a10/14 proteins involved in lipid metabolism and upregulation of genes involved in cholesterol biosynthesis. Majority of the gene expression changes were corrected by PAH and PAL delivery though the role of these changes in PKU pathology is currently unclear. Taken together, here we show that blood Phe lowering strategy using PAH or PAL corrects both brain pathology as well as previously unknown lipid metabolism associated pathway changes in liver.

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 104-105
Author(s):  
Shihuan Kuang ◽  
Feng Yue ◽  
Stephanie Oprescu

Abstract Single Cell RNA-sequencing (scRNA-seq) is a powerful technique to deconvolute gene expression of various subset of cells intermingled within a complex tissue, such as the skeletal muscle. We first used scRNA-seq to understand dynamics of cell populations and their gene expression during muscle regeneration in murine limb muscles. This leads to the identification of a subset of satellite cells (the resident stem cells of skeletal muscles) with immune gene signatures in regenerating muscles. Next, we used scRNA-seq to examine gene expression dynamics of satellite cells at various status: quiescence, activation, proliferation, differentiation and self-renewal. This analysis uncovers stage-dependent changes in expression of genes related to lipid metabolism. Further analyses lead to the discovery of previously unappreciated dynamics of lipid droplets in satellite cells; and demonstrate that the abundance of the lipid droplets in newly divided satellite daughter cells is linked to cell fate segregation into differentiation versus self-renewal. Perturbation of lipid droplet dynamics through blocking lipolysis disrupts cell fate homeostasis and impairs muscle regeneration. Finally, we show that lipid metabolism regulates the function of satellite cells through two mechanisms. On one hand, lipid metabolism functions as an energy source through fatty acid oxidation (FAO), and blockage of FAO reduces energy production that is critical for satellite cell function. On the other hand, lipid metabolism generates bioactive molecules that influence signaling transduction and gene expression. In this scenario, lipid metabolism and FAO regulate the intracellular levels of acetyl-coA and selective acetylation of PAX7, a pivotal transcriptional factor underlying function of satellite cells. These results together reveal for the first time a critical role of lipid metabolism and lipid droplet dynamics in muscle satellite cell fate determination and regenerative function; and underscore a potential role of dietary fatty acids in satellite cell-dependent muscle development, growth and regeneration.


Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 427 ◽  
Author(s):  
Kyungtae Kim ◽  
Ki Hong Nam ◽  
Sang Ah Yi ◽  
Jong Woo Park ◽  
Jeung-Whan Han ◽  
...  

Ginsenoside Rg3, one of the major components in Panax ginseng, has been reported to possess several therapeutic effects including anti-obesity properties. However, its effect on the browning of mature white adipocytes as well as the underlying mechanism remains poorly understood. In this study, we suggested a novel role of Rg3 in the browning of mature 3T3-L1 adipocytes by upregulating browning-related gene expression. The browning effects of Rg3 on differentiated 3T3-L1 adipocytes were evaluated by analyzing browning-related markers using quantitative PCR, immunoblotting, and immunostaining. In addition, the size and sum area of lipid droplets in differentiated 3T3-L1 adipocytes were measured using Oil-Red-O staining. In mature 3T3-L1 adipocytes, Rg3 dose-dependently induced the expression of browning-related genes such as Ucp1, Prdm16, Pgc1α, Cidea, and Dio2. Moreover, Rg3 induced the expression of beige fat-specific genes (CD137 and TMEM26) and lipid metabolism-associated genes (FASN, SREBP1, and MCAD), which indicated the activation of lipid metabolism by Rg3. We also demonstrated that activation of 5’ adenosine monophosphate-activated protein kinase (AMPK) is required for Rg3-mediated up-regulation of browning gene expression. Moreover, Rg3 inhibited the accumulation of lipid droplets and reduced the droplet size in mature 3T3-L1 adipocytes. Taken together, this study identifies a novel role of Rg3 in browning of white adipocytes, as well as suggesting a potential mechanism of an anti-obesity effect of Panax ginseng.


2021 ◽  
Author(s):  
Chao Wang ◽  
Zhi Yang ◽  
En Xu ◽  
Xingzhou Wang ◽  
Zijian Li ◽  
...  

Abstract Background: Peritoneal metastasis (PM) occurs frequently in patients with gastric cancer (GC) and confers poor survival. Lipid metabolism and epithelial-mesenchymal transition (EMT) play an important role in GC metastasis. As Apolipoprotein C-II (APOC2) is a key protein in lipid metabolism, few studies have investigated the role of APOC2 in PM. This study aims to elucidate the potential molecular mechanism of APOC2 in the PM of GC.Methods: The Tandem Mass Tagging (TMT) method followed by liquid chromatography-tandem mass spectrometry-based proteomics analysis was used to compare the levels of differentially expressed proteins between human PM and GC tissues. APOC2 expression was evaluated by immunoblotting, and immunohistochemistry analysis (n = 111). APOC2 over-expression and knock-down expression cell models were developed and tested in vitro. RNA sequencing analysis evaluated the changes in gene expression after APOC2 knockdown in GC cells. The Agilent Seahorse XF platform and lipid staining assay were used to evaluate the role of APOC2 in lipid metabolism of GC cells. Spheroid cell invasion assay, apoptosis assay, colony formation assay, wound-healing assays, and transwell assays were performed and peritoneal implants into nude mice were done to assess the biological effects of APOC2. The underlying mechanisms were investigated using Western blot, inhibitor or activator treatment assays.Results: APOC2 was highly abundant in GC cells and PM tissues. And high APOC2 levels in GC tissues correlated with poor patient prognosis. Knockdown of APOC2 inhibited the malignant phenotype of cancer cells and EMT significantly. Massive gene expression alterations after APOC2 knockdown, which were associated with various signaling pathways, especially the PI3K/AKT signaling pathway and lipid metabolism. Furthermore, the regulatory effects of APOC2 on the EMT were partially attributed to the PI3K/AKT/mTOR signaling pathway. The results in vivo also showed that APOC2 modulated GC PM.Conclusions: We verified that knockdown of APOC2 suppressed GC cell Lipid metabolism, proliferation, migration, invasion, and EMT, accompanied by inactivation of PI3K/AKT/mTOR signaling pathway. APOC2 overexpression had the opposite effects GC cell phenotypes and mechanisms. Collectively, our results identified APOC2 in PM as a potential therapeutic target.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 994
Author(s):  
Laura Bordoni ◽  
Irene Petracci ◽  
Fanrui Zhao ◽  
Weihong Min ◽  
Elisa Pierella ◽  
...  

Dietary lipids have a major role in nutrition, not only for their fuel value, but also as essential and bioactive nutrients. This narrative review aims to describe the current evidence on nutrigenomic effects of dietary lipids. Firstly, the different chemical and biological properties of fatty acids contained both in plant- and animal-based food are illustrated. A description of lipid bioavailability, bioaccessibility, and lipotoxicity is provided, together with an overview of the modulatory role of lipids as pro- or anti-inflammatory agents. Current findings concerning the metabolic impact of lipids on gene expression, epigenome, and gut microbiome in animal and human studies are summarized. Finally, the effect of the individual’s genetic make-up on lipid metabolism is described. The main goal is to provide an overview about the interaction between dietary lipids and the genome, by identifying and discussing recent scientific evidence, recognizing strengths and weaknesses, to address future investigations and fill the gaps in the current knowledge on metabolic impact of dietary fats on health.


Author(s):  
Anna Maria Bennati ◽  
Marilena Castelli ◽  
Maria Agnese Della Fazia ◽  
Tommaso Beccari ◽  
Donatella Caruso ◽  
...  

2008 ◽  
Vol 2 ◽  
pp. LPI.S866 ◽  
Author(s):  
Vesa M. Olkkonen

Oxysterols are naturally occurring oxidized derivatives of cholesterol, or by-products of cholesterol biosynthesis, with multiple biologic functions. These compounds display cytotoxic, pro-apoptotic, and pro-inflammatory activities and may play a role in the pathology of atherosclerosis. Their functions as intermediates in the synthesis of bile acids and steroid hormones, and as readily transportable forms of sterol are well established. During the past decade, however, novel physiologic activities of oxysterols have emerged. They are now thought to act as endogenous regulators of gene expression in lipid metabolism. Recently, new intracellular oxysterol receptors have been identified and novel functions of oxysterols in cell signaling discovered, evoking novel interest in these compounds in several branches of biomedical research.


2019 ◽  
Vol 317 (1) ◽  
pp. R49-R58 ◽  
Author(s):  
Dorien Reijnders ◽  
Kelsey N. Olson ◽  
Chin-Chi Liu ◽  
Kalie F. Beckers ◽  
Sujoy Ghosh ◽  
...  

The hypertensive pregnancy disorder preeclampsia (PE) is a leading cause of fetal and maternal morbidity/mortality. Obesity increases the risk to develop PE, presumably via the release of inflammatory mediators from the adipose tissue, but the exact etiology remains largely unknown. Using obese PE-like blood pressure high subline 5 (BPH/5) and lean gestational age-matched C57Bl6 mice, we aimed to obtain insight into differential reproductive white adipose tissue (rWAT) gene expression, circulating lipids and inflammation at the maternal-fetal interface during early pregnancy. In addition, we investigated the effect of 7 days 25% calorie restriction (CR) in early pregnancy on gene expression in rWAT and implantation sites. Compared with C57Bl6, female BPH/5 are dyslipidemic before pregnancy and show an amplification of rWAT mass, circulating cholesterol, free fatty acids, and triacylglycerol levels throughout pregnancy. RNA sequencing showed that pregnant BPH/5 mice have elevated gene enrichment in pathways related to inflammation and cholesterol biosynthesis at embryonic day ( e) 7.5. Expression of cholesterol-related HMGCS1, MVD, Cyp51a1, and DHCR was validated by quantitative reverse-transcription-polymerase chain reaction. CR during the first 7 days of pregnancy restored the relative mRNA expression of these genes to a level comparable to C57Bl6 pregnant females and reduced the expression of circulating leptin and proinflammatory prostaglandin synthase 2 in both rWAT and implantation sites in BPH/5 mice at e7.5. Our data suggest a possible role for rWAT in the dyslipidemic state and inflammatory uterine milieu that might underlie the pathogenesis of PE. Future studies should further address the physiological functioning of the adipose tissue in relation to PE-related pregnancy outcomes.


2013 ◽  
Vol 54 ◽  
pp. 79-90 ◽  
Author(s):  
Saba Valadkhan ◽  
Lalith S. Gunawardane

Eukaryotic cells contain small, highly abundant, nuclear-localized non-coding RNAs [snRNAs (small nuclear RNAs)] which play important roles in splicing of introns from primary genomic transcripts. Through a combination of RNA–RNA and RNA–protein interactions, two of the snRNPs, U1 and U2, recognize the splice sites and the branch site of introns. A complex remodelling of RNA–RNA and protein-based interactions follows, resulting in the assembly of catalytically competent spliceosomes, in which the snRNAs and their bound proteins play central roles. This process involves formation of extensive base-pairing interactions between U2 and U6, U6 and the 5′ splice site, and U5 and the exonic sequences immediately adjacent to the 5′ and 3′ splice sites. Thus RNA–RNA interactions involving U2, U5 and U6 help position the reacting groups of the first and second steps of splicing. In addition, U6 is also thought to participate in formation of the spliceosomal active site. Furthermore, emerging evidence suggests additional roles for snRNAs in regulation of various aspects of RNA biogenesis, from transcription to polyadenylation and RNA stability. These snRNP-mediated regulatory roles probably serve to ensure the co-ordination of the different processes involved in biogenesis of RNAs and point to the central importance of snRNAs in eukaryotic gene expression.


1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S130-S131
Author(s):  
M. J. MÜLLER ◽  
A. G. BURGER ◽  
E. JEQUIER ◽  
K.J. ACHESON

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