A novel, multitargeted endogenous metabolic modulator composition impacts metabolism, inflammation, and fibrosis in nonalcoholic steatohepatitis-relevant primary human cell models

AbstractNonalcoholic steatohepatitis (NASH) is a complex metabolic disease of heterogeneous and multifactorial pathogenesis that may benefit from coordinated multitargeted interventions. Endogenous metabolic modulators (EMMs) encompass a broad set of molecular families, including amino acids and related metabolites and precursors. EMMs often serve as master regulators and signaling agents for metabolic pathways throughout the body and hold the potential to impact a complex metabolic disease like NASH by targeting a multitude of pathologically relevant biologies. Here, we describe a study of a novel EMM composition comprising five amino acids and an amino acid derivative (Leucine, Isoleucine, Valine, Arginine, Glutamine, and N-acetylcysteine [LIVRQNac]) and its systematic evaluation across multiple NASH-relevant primary human cell model systems, including hepatocytes, macrophages, and stellate cells. In these model systems, LIVRQNac consistently and simultaneously impacted biology associated with all three core pathophysiological features of NASH—metabolic, inflammatory, and fibrotic. Importantly, it was observed that while the individual constituent amino acids in LIVRQNac can impact specific NASH-related phenotypes in select cell systems, the complete combination was necessary to impact the range of disease-associated drivers examined. These findings highlight the potential of specific and potent multitargeted amino acid combinations for the treatment of NASH.

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NORMAL DISTRIBUTIONS OF AMINO ACIDS IN BODY FLUIDS

PEDIATRICS ◽

10.1542/peds.42.3.391 ◽

1968 ◽

Vol 42 (3) ◽

pp. 391-392

Author(s):

Charles R. Scriver

Keyword(s):

Metabolic Disease ◽

Amino Acids ◽

Amino Acid ◽

Body Fluids ◽

The Body ◽

Great Effort ◽

Normal Distributions ◽

Screening Programs ◽

Abnormal Accumulation ◽

The Many

Great significance is often attached to the detection of an abnormal accumulation of an amino acid in the body fluids of a patient, for this can be the manifestation of an amino-acidopathv. Screening programs designed to discover latent hereditary metabolic disease are frequently dependent on their ability to discriminate a single sample showing an abnormal concentration of a metabolite from the many thousands of normal samples. It is tacitly assumed in such circumstances that we know what is "normal." To achieve an understanding of the normal distribution of amino acids in physiological fluids of man has required much time and great effort. An earlier Commentary1 described this well.

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Role of Chiral Configuration in the Photoinduced Interaction of D- and L-Tryptophan with Optical Isomers of Ketoprofen in Linked Systems

International Journal of Molecular Sciences ◽

10.3390/ijms22126198 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6198

Author(s):

Aleksandra A. Ageeva ◽

Ilya M. Magin ◽

Alexander B. Doktorov ◽

Victor F. Plyusnin ◽

Polina S. Kuznetsova ◽

...

Keyword(s):

Amino Acid ◽

Excited States ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Dipole Interaction ◽

The Body ◽

Model Systems ◽

Optical Isomers ◽

Amino Acid Properties ◽

Parkinson’S Diseases

The study of the L- and D-amino acid properties in proteins and peptides has attracted considerable attention in recent years, as the replacement of even one L-amino acid by its D-analogue due to aging of the body is resulted in a number of pathological conditions, including Alzheimer’s and Parkinson’s diseases. A recent trend is using short model systems to study the peculiarities of proteins with D-amino acids. In this report, the comparison of the excited states quenching of L- and D-tryptophan (Trp) in a model donor–acceptor dyad with (R)- and (S)-ketoprofen (KP-Trp) was carried out by photochemically induced dynamic nuclear polarization (CIDNP) and fluorescence spectroscopy. Quenching of the Trp excited states, which occurs via two mechanisms: prevailing resonance energy transfer (RET) and electron transfer (ET), indeed demonstrates some peculiarities for all three studied configurations of the dyad: (R,S)-, (S,R)-, and (S,S)-. Thus, the ET efficiency is identical for (S,R)- and (R,S)-enantiomers, while RET differs by 1.6 times. For (S,S)-, the CIDNP coefficient is almost an order of magnitude greater than for (R,S)- and (S,R)-. To understand the source of this difference, hyperpolarization of (S,S)-and (R,S)- has been calculated using theory involving the electron dipole–dipole interaction in the secular equation.

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Unusual Aggregation Properties of Single Amino Acid L-Lysine Hydrochloride

10.26434/chemrxiv.14152976 ◽

2021 ◽

Author(s):

Bharti Koshti ◽

Ramesh Singh ◽

Vivekshinh Kshtriya ◽

Shanka Walia ◽

Dhiraj Bhatia ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Self Assembly ◽

Short Term Memory ◽

Deionized Water ◽

The Body ◽

The Self ◽

Single Amino Acid ◽

Maple Syrup ◽

Self Assembling

. The self-assembly of single amino acids is very important topic of research since there are plethora of diseases like phenylketonuria, tyrosinemia, hypertryptophanemia, hyperglycinemia, cystinuria and maple syrup urine disease to name a few which are caused by the accumulation or excess of amino acids. These are in-born errors of metabolisms (IEM’s) which are caused due to the deficiency of enzymes involved in catabolic pathways of these enzymes. Hence, it is very pertinent to understand the fate of these excess amino acids in the body and their self-assembling behaviour at molecular level. From the previous literature reports it may be surmised that the single amino acids like Phenylalanine, Tyrosine, Tryptophan, Cysteine and Methionine assemble to amyloid like structures, and hence have important implications in the pathophysiology of IEM’s like phenylketonuria, tyrosinemia, hypertryptophanemia, cystinuria and hypermethioninemia respectively. In this manuscript we report the self-assembly of lysine hydrocholride to fiber like structures in deionized water. It could be observed that lysine assemble to globular structures in fresh condition and then gradually changes to fiber like morphologies by self-association over time after 24 hours. These fibers gradually change to tubular morphologies after 3 day followed by fractal irregular morphologies in 10 and 15 days respectively. Notably, lysine exists as positively charged amino acid at physiological pH and the amine groups in lysine remain protonated. Hence, the self-assembling properties of lysine hydrochloride in deionized water is also pertinent and give insights into the fate of this amino acid in body in case it remains unmetabolized. Further, MTT assays were done to analyse the toxicities of these aggregates and the assay suggest their cytotoxic nature on SHSY5Y neural cell lines. Hence, the aggregation of lysine may be attributed to the pathological symptoms caused in diseases like hyperlysinemia which is associated with the neurological problems like seizures and short-term memory as observed in case of amyloid diseases like Parkinson’s and Alzheimer’s to name a few.

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Consistency and Change

Molecules, Microbes, and Meals ◽

10.1093/oso/9780190687694.003.0006 ◽

2019 ◽

Author(s):

Alan Kelly

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Living Organism ◽

Peptide Bond ◽

The Body ◽

Blood Proteins ◽

Genes Encoding ◽

Fundamental Phenomenon ◽

P Proteins

Proteins are, in my view, the most impressive molecules in food. They influence the texture, crunch, chew, flow, color, flavor, and nutritional quality of food. Not only that, but they can radically change their properties and how they behave depending on the environment and, critically for food, in response to processes like heating. Even when broken down into smaller components they are important, for example giving cheese many of its critical flavor notes. Indeed, I would argue that perhaps the most fundamental phenomenon we encounter in cooking or processing food is the denaturation of proteins, as will be explained shortly. Beyond food, the value of proteins and their properties is widespread across biology. Many of the most significant molecules in our body and that of any living organism (including plants and animals) are proteins. These include those that make hair and skin what they are, as well as the hemoglobin that transports oxygen around the body in our blood. Proteins are built from amino acids, a family of 20 closely related small molecules, which all have in chemical terms the same two ends (chemically speaking, an amino end and an acidic end, hence the name) but differ in the middle. This bit in the middle varies from amino acid to amino acid, from simple (a hydrogen atom in the case of glycine, the simplest amino acid) to much more complex structures. Amino acids can link up very neatly, as the amino end of one can form a bond (called a peptide bond) with the acid end of another, and so forth, so that chains of amino acids are formed that, when big enough (more than a few dozen amino acids), we call proteins. Our bodies produce thousands of proteins for different functions, and the instructions for which amino acids combine to make which proteins are essentially what the genetic code encrypted in our DNA specifies. We hear a lot about our genes encoding the secrets of life, but what that code spells is basically P-R-O-T-E-I-N. Yes, these are very important molecules!

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Conversion Percentage of Tryptophan to Nicotinamide is Higher in Rice Protein Diet than in Wheat Protein Diet in Rats

International Journal of Tryptophan Research ◽

10.4137/ijtr.s22444 ◽

2015 ◽

Vol 8 ◽

pp. IJTR.S22444

Author(s):

Katsumi Shibata ◽

Tsutomu Fukuwatari ◽

Tomoyo Kawamura

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Body Weight Gain ◽

Acid Value ◽

Amino Acid Mixture ◽

The Body ◽

Protein Diet ◽

Acid Mixture ◽

Wheat Protein ◽

Rice Protein

We reported previously that the pellagragenic property of corn protein is not only low L-tryptophan concentration but also the lower conversion percentage of L-tryptophan to nicotinamide; the amino acid composition greatly affected the conversion percentage. The amino acid value of wheat protein is lower than that of rice protein. In the present study, we compare the conversion percentages of L-tryptophan to nicotinamide between wheat protein and rice protein diets in growing rats. The body weight gain for 28 days in rats fed with a 10% amino acid mixture diet with wheat protein was lower than that of rats fed with a 10% amino acid diet with rice protein (68.1 ± 1.6 g vs 108.4 ± 1.9 g; P < 0.05). The conversion percentage of L-tryptophan to nicotinamide was also lower for the wheat protein diet compared with the rice protein diet (1.44 ± 0.036% vs 2.84 ± 0.19%; P < 0.05). The addition of limiting amino acids (L-isoleucine, L-lysine, L-tryptophan, L-methionine, L-threonine) to the wheat protein diet improved growth and the conversion percentage. In conclusion, our result supports the thinking that the composition of amino acids affects the conversion ratio of L-tryptophan to nicotinamide.

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In vivo Determination of Amino Acid Bioavailability in Humans and Model Animals

Journal of AOAC International ◽

10.1093/jaoac/88.3.923 ◽

2005 ◽

Vol 88 (3) ◽

pp. 923-934 ◽

Cited By ~ 36

Author(s):

Malcolm F Fuller ◽

Daniel Tomé

Keyword(s):

Amino Acids ◽

Amino Acid ◽

The Body ◽

Whole Body ◽

Intestinal Lumen ◽

Stable Isotope Labelling ◽

Ileal Digestibility ◽

Hydrolyzed Protein ◽

Protein Free Diet

Abstract Because the digestion of many dietary proteins is incomplete, and because there is a continuous (but variable) entry into the intestinal lumen of endogenous protein and amino acid nitrogen that is also subject to digestion, the fluxes of nitrogen, amino acids, and protein in the gut exhibit a rather complicated pattern. Methods to distinguish and quantitate the endogenous and dietary components of nitrogen and amino acids in ileal chyme or feces include the use of a protein-free diet, the enzyme-hydrolyzed protein method, different levels of protein intake, multiple regression methods, and stable-isotope labelling of endogenous or exogenous amino acids. Assessment of bioavailability can be made, with varying degrees of difficulty, in man directly but, for routine evaluation of foods, the use of model animals is attractive for several reasons, the main ones being cost and time. Various animals and birds have been proposed as models for man but, in determining their suitability as a model, their physiological, enzymological, and microbiological differences must be considered. Fecal or ileal digestibility measurements, as well as apparent and true nitrogen and amino acid digestibility measurements, have very different nutritional significance and can, thus, be used for different objectives. Measurements at the ileal level are critical for determining amino acid losses of both dietary and endogenous origin, whereas measurements at the fecal level are critical in assessing whole-body nitrogen losses. A complementary and still unresolved aspect is to take into account the recycling of intestinal nitrogen and bacterial amino acids to the body.

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The metabolic utilization of amino acids: potentials of 14CO2 breath test measurements

British Journal Of Nutrition ◽

10.1079/bjn19920024 ◽

1992 ◽

Vol 67 (2) ◽

pp. 207-214 ◽

Cited By ~ 12

Author(s):

V. V. A. M. Schreurs ◽

H. A. Boekholt ◽

R. E. Koopmanschap ◽

P. J. M. Weijs

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Breath Test ◽

Relative Rate ◽

The Body ◽

Adult Rats ◽

Total Oxidation ◽

Amino Acid Utilization ◽

Amino Acid Requirements ◽

14Co2 Breath Test

The present paper offers a dual 14CO2 breath test approach to study the metabolic utilization of free amino acids in the body. Using the carboxyl-[14C]isotopomer of an amino acid as the test substrate the percentage recovery of the isotope as 14CO2 reflects which part of the labelled amino acid flux has been decarboxylated. The residual C fragments may flow to total oxidation at least to the level recovered for the universal [14C]isotopomer. In the case that recovery for total oxidation is less than for decarboxylation, part of the [14C]fragments are retained in the body by either exchange or non-oxidative pathways. Utilization of tyrosine and leucine was measured in the post-absorptive phase in adult rats conditioned on isoenergetic diets containing 210, 75 or 0 g protein/kg. It was shown that the level of dietary protein exerts an influence on both decarboxylation and total oxidation. Although the responses of leucine and tyrosine were not different for total oxidation, there was a difference between the amino acids in their relative rate of decarboxylation. That this dual 14CO2 breath test approach can be used as a tool to evaluate whether the protein and amino acid supply has been adequate to support actual requirements is discussed.Amino acid utilization: Amino acid requirements: Leucine: Tyrosine

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The case for regulating indispensable amino acid metabolism: the branched-chain α-keto acid dehydrogenase kinase-knockout mouse

Biochemical Journal ◽

10.1042/bj20061506 ◽

2006 ◽

Vol 400 (1) ◽

Cited By ~ 15

Author(s):

Susan M. Hutson

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Essential Amino Acids ◽

The Body ◽

Keto Acid ◽

Acid Dehydrogenase ◽

Indispensable Amino Acid ◽

Branched Chain

BCAAs (branched-chain amino acids) are indispensable (essential) amino acids that are required for body protein synthesis. Indispensable amino acids cannot be synthesized by the body and must be acquired from the diet. The BCAA leucine provides hormone-like signals to tissues such as skeletal muscle, indicating overall nutrient sufficiency. BCAA metabolism provides an important transport system to move nitrogen throughout the body for the synthesis of dispensable (non-essential) amino acids, including the neurotransmitter glutamate in the central nervous system. BCAA metabolism is tightly regulated to maintain levels high enough to support these important functions, but at the same time excesses are prevented via stimulation of irreversible disposal pathways. It is well known from inborn errors of BCAA metabolism that dysregulation of the BCAA catabolic pathways that leads to excess BCAAs and their α-keto acid metabolites results in neural dysfunction. In this issue of Biochemical Journal, Joshi and colleagues have disrupted the murine BDK (branched-chain α-keto acid dehydrogenase kinase) gene. This enzyme serves as the brake on BCAA catabolism. The impaired growth and neurological abnormalities observed in this animal show conclusively the importance of tight regulation of indispensable amino acid metabolism.

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Response of adult rats to deficiencies of different essential amino acids

British Journal Of Nutrition ◽

10.1079/bjn19740007 ◽

1974 ◽

Vol 31 (1) ◽

pp. 47-57 ◽

Cited By ~ 18

Author(s):

A. K. Said ◽

D. M. Hegsted ◽

K. C. Hayes

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Nutritive Value ◽

Plasma Concentrations ◽

Essential Amino Acids ◽

The Body ◽

Adult Rats ◽

Short Period ◽

Body Weights ◽

Fatty Livers

1. Adult rats were fed on diets free of either lysine, methionine, threonine or protein. The threonine- and protein-deficient animals lost weight at approximately the same rate, about 100 g in 14 weeks, at which time several were moribund. In contrast, lysine-deficient animals lost only about 30 g in 14 weeks and had lost only 46 g after 22 weeks, when they were killed. Methionine-deficient animals showed an intermediate response. Losses in weight of several tissues – kidney, heart and two muscles – were related to, but not necessarily proportional to, the loss of body-weight. Liver weights relative to body-weights were large in lysine- and threonine-deficient animals and smallest in methionine-deficient animals.2. Adult rats were fed on diets containing zero, a moderate amount (about twice the estimated minimal requirement) or an excess (about four times the estimated requirement) of lysine or threonine in all combinations (3 × 3 design). Analysis of variance of the body-weights, tissue weights and tissue nitrogen contents indicated, in general, a significant effect of each amino acid, as expected, but also, in most instances, a significant interaction. Plasma concentrations of lysine and threonine were affected by the intakes of the respective amino acids, but plasma lysine concentrations were also affected by the threonine intake.3. Liver histology also suggested significant interactions between the two amino acids. Animals given no lysine but moderate amounts of threonine developed severely fatty livers; next most severely affected were animals receiving excess of both amino acids. Threonine deficiency, in the presence or absence of lysine, produced moderately fatty livers similar to those seen in protein-deficient animals.4. Since animals have varying ability to conserve body nitrogen when they are fed on diets limiting in different essential amino acids, measurements of biological value (BV) and net protein utilization by conventional methods, over a short period of time, over-estimate nutritive value relative to amino acid score and probably over-estimate the true nutritive value of poor-quality proteins, particularly those limiting in lysine. If so, this is a serious error, since it leads to underestimates of the protein requirements if BV is used. The fact that certain tissues, particularly the liver, do not necessarily lose nitrogen in proportion to total body nitrogen and may show specific pathological effects depending on the limiting amino acid or the proportions of amino acids in the diet also indicates that general measures of nitrogen economy may not be sufficiently discriminating tests of the nutritive value of proteins.

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Intestinal peptidases form functional complexes with the neutral amino acid transporter B0AT1

Biochemical Journal ◽

10.1042/bj20120307 ◽

2012 ◽

Vol 446 (1) ◽

pp. 135-148 ◽

Cited By ~ 40

Author(s):

Stephen J. Fairweather ◽

Angelika Bröer ◽

Megan L. O'Mara ◽

Stefan Bröer

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Brush Border ◽

Brush Border Membrane ◽

Amino Acid Transporter ◽

The Body ◽

Site Directed Mutagenesis ◽

Substrate Affinity ◽

Xenopus Laevis Oocytes ◽

Acid Transporter

The brush-border membrane of the small intestine and kidney proximal tubule are the major sites for the absorption and re-absorption of nutrients in the body respectively. Transport of amino acids is mediated through the action of numerous secondary active transporters. In the mouse, neutral amino acids are transported by B0AT1 [broad neutral (0) amino acid transporter 1; SLC6A19 (solute carrier family 6 member 19)] in the intestine and by B0AT1 and B0AT3 (SLC6A18) in the kidney. Immunoprecipitation and Blue native electrophoresis of intestinal brush-border membrane proteins revealed that B0AT1 forms complexes with two peptidases, APN (aminopeptidase N/CD13) and ACE2 (angiotensin-converting enzyme 2). Physiological characterization of B0AT1 expressed together with these peptidases in Xenopus laevis oocytes revealed that APN increased the substrate affinity of the transporter up to 2.5-fold and also increased its surface expression (Vmax). Peptide competition experiments, in silico modelling and site-directed mutagenesis of APN suggest that the catalytic site of the peptidase is involved in the observed changes of B0AT1 apparent substrate affinity, possibly by increasing the local substrate concentration. These results provide evidence for the existence of B0AT1-containing digestive complexes in the brush-border membrane, interacting differentially with various peptidases, and responding to the dynamic needs of nutrient absorption in the intestine and kidney.

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