The cellular prion protein does not affect tau seeding and spreading of sarkosyl-insoluble fractions from Alzheimer's disease.

The cellular prion protein (PrPC) plays many roles in the developing and adult brain. In addition, PrPC binds to several amyloids in oligomeric and prefibrillar forms and may act as a putative receptor of abnormal misfolded protein species. The role of PrPC in tau seeding and spreading is not known. In the present study, we have inoculated well-characterized sarkosyl-insoluble fractions of sporadic Alzheimer's disease (sAD) into the brain of adult wild-type mice (Prnp+/+), Prnp0/0 (ZH3 strain) mice, and mice over-expressing the secreted form of PrPC lacking their GPI anchor (Tg44 strain). Phospho-tau (ptau) seeding and spreading involving neurons and oligodendrocytes were observed three and six months after inoculation. 3Rtau and 4Rtau deposits from the host tau, as revealed by inoculating Mapt0/0 mice and by using specific anti-mouse and anti-human tau antibodies suggest modulation of exon 10 splicing of the host mouse Mapt gene elicited by exogenous sAD-tau. However, no tau seeding and spreading differences were observed among Prnp genotypes. Our results show that PrPC does not affect tau seeding and spreading in vivo.

Structure and Characterization of Catanionic Complexes and Biocompatible Vesicles of N-Acyltaurine and Sarcosine Alkyl Ester: Encapsulation and Release Studies with 5-Fluorouracil.

Hydrated dispersions containing equimolar mixtures of cationic and anionic amphiphiles, referred to as catanionic systems, exhibit synergistic physicochemical properties, and mixing single-chain cationic and anionic lipids can lead to the spontaneous formation of vesicles as well as other phase structures. In the present work, we have characterized two catanionic systems prepared by mixing N-acyltaurines (NATs) and sarcosine alkyl esters (SAEs) bearing 11 and 12 C atoms in the acyl/alkyl chains. Turbidimetric and isothermal titration calorimetric studies revealed that both NATs form equimolar complexes with SAEs having matching acyl/alkyl chains. The three-dimensional structure of the sarcosine lauryl ester (lauryl sarcosinate, LS)-N-lauroyltaurine (NLT) equimolar complex has been determined by single-crystal X-ray diffraction. The LS-NLT equimolar complex is stabilized by electrostatic attraction and multiple hydrogen bonds, including classical, strong N-H···O hydrogen bonds as well as several C-H···O hydrogen bonds between the two amphiphiles. DSC studies showed that both equimolar complexes show single sharp phase transitions. Transmission electron microscopy and dynamic light scattering studies have demonstrated that the LS-NLT catanionic complex assemblies yield stable medium-sized vesicles (diameter 280-350 nm). These liposomes were disrupted at high pH, suggesting that the designed catanionic complexes can be used to develop base-labile drug delivery systems. In vitro studies with these catanionic liposomes showed efficient entrapment (73% loading) and release of the anticancer drug 5-fluorouracil in the physiologically relevant pH range of 6.0-8.0. The release rate was highest at pH 8.0, reaching about 78%, 90%, and 100% drug release at 2, 6, and 12 h, respectively. These observations indicate that LS-NLT catanionic vesicles will be useful for designing drug delivery systems, particularly for targeting organs such as the colon, which are inherently at basic pH.

Effects of sodium dodecyl sulfate, Sarkosyl and sodium lauroyl glutamate on the structure of proteins monitored by agarose native gel electrophoresis and circular dichroism.

We have studied binding properties of three detergents, i.e., sodium dodecyl sulfate (SDS), Sarkosyl and sodium lauroyl glutamate (SLG), to model proteins based on their effects on electrophoretic mobilities of the proteins using agarose native gel electrophoresis and circular dichroism (CD). This simple technology can evaluate the dissociative properties of bound detergents from the proteins and their effects on protein structure. SDS influenced the electrophoretic mobilities of all model proteins more strongly than the other two detergents, implying a stronger inclination for protein binding and subsequent alterations in protein structure or reductions in activity, which are supported by CD analysis. On the contrary, Sarkosyl and SLG showed weaker binding and interfered less with the structure and biological activities, indicating that these detergents may be useful for protein purification and analysis. It appeared that SLG was weaker in protein binding than Sarkosyl, although the effects of these two detergents appeared to depend on the proteins.

Biochemical characterization of paralyzed flagellum proteins A (PflA) and B (PflB) from Helicobacter pylori flagellar motor.

Motility by means of flagella plays an important role in the persistent colonization of Helicobacter pylori in the human stomach. The H. pylori flagellar motor has a complex structure that includes a periplasmic scaffold, the components of which are still being identified. Here, we report the isolation and characterization of the soluble forms of two putative essential H. pylori motor scaffold components, proteins PflA and PflB. We developed an on-column refolding procedure, overcoming the challenge of inclusion body formation in Escherichia coli. We employed mild detergent sarkosyl to enhance protein recovery and n-dodecyl-N,N-dimethylamine-N-oxide (LDAO)-containing buffers to achieve optimal solubility and monodispersity. In addition, we showed that PflA lacking the ß-rich N-terminal domain is expressed in a soluble form, and behaves as a monodisperse monomer in solution. The methods for producing the soluble, folded forms of H. pylori PflA and PflB established in this work will facilitate future biophysical and structural studies aimed at deciphering their location and their function within the flagellar motor.

Metabolic profiling of psoriasis vulgaris and palmoplantar pustulosis.

Psoriasis is a chronic inflammatory skin disorder with various subtypes, including psoriasis vulgaris (PV) and palmoplantar pustulosis (PPP). Metabolomics studies have provided insights into psoriasis pathogenesis. However, research on metabolomic alterations in PV and PPP patients is limited. We aimed to explore and compare the metabolic profiles of patients with PV and PPP to those of healthy volunteers (HVs). A single-centre retrospective cohort was constructed, comprising Korean patients with psoriasis and HVs matched by age and sex. Clinical information including demographics, disease severity, and comorbidities were collected. Plasma samples were subjected to targeted metabolic analysis using an Absolute IDQ®p180 kit, which quantified 188 metabolites, including amino acids and carnitines. Statistical significance was assessed using an independent t-test and chi-square test, with p-values adjusted by the Benjamini-Hochberg procedure. Pathway analyses were employed to gain a comprehensive understanding of the metabolite profile. This study included 93 patients (73 PV and 20 PPP) and an equal number of HVs. PV patients showed increased levels of sarcosine, serotonin, propionylcarnitine, proline, aspartic acid, tyrosine, taurine, spermine and ornithine, but exhibited a decreased level of acetylcarnitine than matched HVs. Notably, sarcosine levels were significantly elevated in PPP patients. Furthermore, the sarcosine/glycine ratio was significantly higher in both PV and PPP patients than in HVs. Pathway analysis showed significant increases in metabolites involved in amino acid metabolism and the urea cycle in PV patients. In conclusion, this study demonstrated distinct metabolic profiles in PV and PPP patients compared to HVs, suggesting sarcosine as a potential biomarker for psoriasis.

Efficacy and safety of add-on sarcosine in patients with major depressive disorder: A randomized controlled trial.

The main hurdles with current therapies for major depressive disorder (MDD) include lack of efficacy, therapeutic latency, and adverse drug reactions. Add-on therapy to conventional antidepressants may result in better therapeutic outcomes to overcome these obstacles. Sarcosine (N-methyl glycine), an endogenous amino acid that acts by modulating the NMDA receptor, is available as a dietary supplement. So, the present study was planned to evaluate the efficacy and safety of add-on sarcosine to SSRIs in MDD. In the present randomized, double-blind clinical trial (NCT04975100), 60 eligible participants with MDD were randomly assigned to either the test group (SSRI + sarcosine) or the control group (SSRI + placebo). Clinical and biochemical parameters like MADRS, CGI, serum BDNF, and serum glycine were assessed at baseline and eight weeks. The mean reduction in MADRS score was significant in both the control (-8.7, 95% CI: -11.0 to -6.4, p < 0.001) and the test group (-13.3, 95% CI: -14.9 to -11.7, p < 0.001), but the change in the test group was significantly greater (-4.6, 95% CI: -7.5 to -1.7, p = 0.003). The test group had a significantly higher response rate (p = 0.007) and remission rate (p = 0.038) compared to the control group. There was a significant increase in serum BDNF in both groups; however, the change in the test group was significantly higher than in the control group (p = 0.041). Similarly, the test group had a significantly higher increase in serum glycine than the control group (p < 0.001). Sarcosine may be considered an efficacious and safe add-on therapy to standard SSRIs in the management of MDD. ClinicalTrial.gov IdentifierNCT04975100.

Enzymatic cascade reactors on carbon nanotube transistor detecting trace prostate cancer biomarker.

Biosensors based on carbon nanotube field-effect transistors (CNT-FETs) have shown great potential in biomarker detection due to their high sensitivity because of appreciable semiconducting electrical properties. However, background signal interferences in complex mediums may results in low signal-to-noise ratio, which may impose challenges for precise biomarker detection in physiological fluids. In this work, we develop an enzymatic CNT-FET, with scalable production at wafer scale, for detection of trace sarcosine that is a biopsy-correlated biomarker of prostate cancer. Enzymatic cascade rectors are constructed on the CNT to improve the reaction efficiency, thereby, enhancing the signal transduction. As such, a limit of detection as low as 105 zM is achieved in buffer solution. Owing to the enhanced reaction efficiency, the testing of clinical serum samples yields significant signal difference to discriminate the prostate cancer (PCa) samples from the benign prostatic hyperplasia (BPH) samples (P = 1.07 × 10-5), demonstrating immense potential in practical applications.

Natural Protein Photon Upconversion Supramolecular Assemblies for Background-Free Biosensing.

The diagnosis of disease biomarkers is crucial for the identification, monitoring, and prognostic assessment of malignant disease. However, biological samples with autofluorescence, complex components, and heterogeneity pose major challenges to reliable biosensing. Here, we report the self-assembly of natural proteins and the triplet-triplet annihilation upconversion (TTA-UC) pair to form upconverted protein clusters (∼8.2 ± 1.1 nm), which were further assembled into photon upconversion supramolecular assemblies (PUSA). This PUSA exhibited unique features, including a small size (∼44.1 ± 4.1 nm), oxygen tolerance, superior biocompatibility, and easy storage via lyophilization, all of which are long sought after for photon upconversion materials. Further, we have revealed that the steric hindrance of the annihilator suppresses the stacking of the annihilator in PUSA, which is vital for maintaining the water dispersibility and enhancing the upconversion performance of PUSA. In conjunction with sarcosine oxidase, this near infrared (NIR)-excitable PUSA nanoprobe could perform background-free biosensing of urinary sarcosine, which is a common biomarker for prostatic carcinoma (PCa). More importantly, this nanoprobe not only allows for qualitative identification of urinary samples from PCa patients by the unaided eye under NIR-light-emitting diode (LED) illumination but also quantifies the concentration of urinary sarcosine. These remarkable findings have propelled photon upconversion materials to a new evolutionary stage and expedited the progress of upconversion biosensing in clinical diagnostics.

Theoretical Study of the Mechanism of the Formation of Azomethine Ylide from Isatine and Sarcosine and Its Reactivity in 1,3-Dipolar Cycloaddition Reaction with 7-Oxabenzonorbornadiene.

The reaction mechanism of tthe formation of azomethine ylides from isatins and sarcosine is addressed in the literature in a general manner. This computational study aims to explore the mechanistic steps for this reaction in detail and to assess the reactivity of formed ylide in a 1,3-dipolar cycloaddition reaction with 7-oxabenzonorbornadiene. For this purpose, density functional theory (DFT) calculations at the M06-2X(SMD,EtOH)/6-31G(d,p) level were employed. The results indicate that CO2 elimination is the rate-determining step, the activation barrier for 1,3-dipolar cycloaddition is lower, and the formed ylide will readily react with dipolarophiles. The substitution of isatine with electron-withdrawal groups slightly decreases the activation barrier for ylide formation.

Longitudinal Analysis of One-Carbon Metabolism-Related Metabolites in Maternal and Cord Blood of Japanese Pregnant Women.

One-carbon metabolism (OCM) is a complex and interconnected network that undergoes drastic changes during pregnancy. In this study, we investigated the longitudinal distribution of OCM-related metabolites in maternal and cord blood and explored their relationships. Additionally, we conducted cross-sectional analyses to examine the interrelationships among these metabolites. This study included 146 healthy pregnant women who participated in the Chiba Study of Mother and Child Health. Maternal blood samples were collected during early pregnancy, late pregnancy, and delivery, along with cord blood samples. We analyzed 18 OCM-related metabolites in serum using stable isotope dilution liquid chromatography/tandem mass spectrometry. We found that serum S-adenosylmethionine (SAM) concentrations in maternal blood remained stable throughout pregnancy. Conversely, S-adenosylhomocysteine (SAH) concentrations increased, and the total homocysteine/total cysteine ratio significantly increased with advancing gestational age. The betaine/dimethylglycine ratio was negatively correlated with total homocysteine in maternal blood for all sampling periods, and this correlation strengthened with advances in gestational age. Most OCM-related metabolites measured in this study showed significant positive correlations between maternal blood at delivery and cord blood. These findings suggest that maternal OCM status may impact fetal development and indicate the need for comprehensive and longitudinal evaluations of OCM during pregnancy.

Enhanced catabolism of glycine betaine and derivatives provides improved osmotic stress protection in Methylorubrum extorquens PA1.

Integration of metabolites into the overall metabolic network of a cell requires careful coordination dependent upon the ultimate usage of the metabolite. Different stoichiometric needs, and thus pathway fluxes, must exist for compounds destined for diverse uses, such as carbon sources, nitrogen sources, or stress-protective agents. Herein, we expand upon our previous work that highlighted the nature of glycine betaine (GB) metabolism in Methylobacteria to examine the utilization of GB-derivative compounds dimethylglycine (DMG) and sarcosine into Methylorubrum extorquens in different metabolic capacities, including as sole nitrogen and/or carbon sources. We isolated gain-of-function mutations that allowed M. extorquens PA1 to utilize dimethylglycine as a carbon source and dimethylglycine and sarcosine as nitrogen source. Characterization of mutants demonstrated selection for variants of the AraC-like regulator Mext_3735 that confer constitutive expression of the GB metabolic gene cluster, allowing direct utilization of the downstream GB derivatives. Finally, among the distinct isolates examined, we found that catabolism of the osmoprotectant used for selection (GB or dimethylglycine) enhanced osmotic stress resistance provided in the presence of that particular osmolyte. Thus, access to the carbon and nitrogen and osmoprotective effects of GB and DMG are made readily accessible through adaptive mutations. In M. extorquens PA1, the limitations to exploiting this group of compounds appear to exist predominantly at the levels of gene regulation and functional activity, rather than being constrained by transport or toxicity.IMPORTANCEOsmotic stress is a common challenge for bacteria colonizing the phyllosphere, where glycine betaine (GB) can be found as a prevalent osmoprotectant. Though Methylorubrum extorquens PA1 cannot use GB or its demethylation products, dimethylglycine (DMG) and sarcosine, as a sole carbon source, utilization is highly selectable via single nucleotide changes for both GB and DMG growth. The innate inability to use these compounds is due to limited flux through steps in the pathway and regulatory constraints. Herein, the characterization of the transcriptional regulator, Mext_3735 (GbdR), expands our understanding of the various roles in which GB derivatives can be used in M. extorquens PA1. Interestingly, increased catabolism of GB and derivatives does not interfere with, but rather improves, the ability of cells to thrive under increased salt stress conditions, suggesting that metabolic flux improves stress tolerance rather than providing a distinct tension between uses.

GlyT1 Inhibition by NFPS Promotes Neuroprotection in Amyloid-ß-Induced Alzheimer's Disease Animal Model.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-ß, leading to N-methyl-D-aspartate (NMDA) receptor-dependent synaptic depression, spine elimination, and memory deficits. Glycine transporter type 1 (GlyT1) modulates glutamatergic neurotransmission via NMDA receptors (NMDAR), presenting a potential alternative therapeutic approach for AD. This study investigates the neuroprotective potential of GlyT1 inhibition in an amyloid-ß-induced AD mouse model. C57BL/6 mice were treated with N-[3-([1,1-Biphenyl]-4-yloxy)-3-(4-fluorophenyl)propyl]-N-methylglycine (NFPS), a GlyT1 inhibitor, 24 h prior to intrahippocampal injection of amyloid-ß. NFPS pretreatment prevented amyloid-ß-induced cognitive deficits in short-term and long-term memory, evidenced by novel object recognition and spatial memory tasks. Moreover, NFPS pretreatment curbed microglial activation, astrocytic reactivity, and subsequent neuronal damage from amyloid-ß injection. An extensive label-free quantitative UPLC-MSE proteomic analysis was performed on the hippocampi of mice treated with NFPS. In proteomics, KEGG enrichment analysis revealed increased in dopaminergic synapse, purine-containing compound biosynthetic process and long-term potentiation, and a reduction in Glucose catabolic process and glycolytic process pathways. The western blot analysis confirmed that NFPS treatment elevated BDNF levels, correlating with enhanced TRKB phosphorylation and mTOR activation. Moreover, NFPS treatment reduced the GluN2B expression after 6 h, which was associated with an increase on CaMKIV and CREB phosphorylation. Collectively, these findings demonstrate that GlyT1 inhibition by NFPS activates diverse neuroprotective pathways, enhancing long-term potentiation signaling and countering amyloid-ß-induced hippocampal damage.

CYP116B5-SOX: An artificial peroxygenase for drug metabolites production and bioremediation.

CYP116B5 is a class VII P450 in which the heme domain is linked to a FMN and 2Fe2S-binding reductase. Our laboratory has proved that the CYP116B5 heme domain (CYP116B5-hd) is capable of catalyzing the oxidation of substrates using H2O2. Recently, the Molecular Lego approach was applied to join the heme domain of CYP116B5 to sarcosine oxidase (SOX), which provides H2O2 in-situ by the sarcosine oxidation. In this work, the chimeric self-sufficient fusion enzyme CYP116B5-SOX was heterologously expressed, purified, and characterized for its functionality by absorbance and fluorescence spectroscopy. Differential scanning calorimetry (DSC) experiments revealed a TM of 48.4 ± 0.04 and 58.3 ± 0.02°C and a enthalpy value of 175,500 ± 1850 and 120,500 ± 1350 cal mol-1 for the CYP116B5 and SOX domains respectively. The fusion enzyme showed an outstanding chemical stability in presence of up to 200 mM sarcosine or 5 mM H2O2 (4.4 ± 0.8 and 11.0 ± 2.6% heme leakage respectively). Thanks to the in-situ H2O2 generation, an improved kcat/KM for the p-nitrophenol conversion was observed (kcat of 20.1 ± 0.6 min-1 and KM of 0.23 ± 0.03 mM), corresponding to 4 times the kcat/KM of the CYP116B5-hd. The aim of this work is the development of an engineered biocatalyst to be exploited in bioremediation. In order to tackle this challenge, an E. coli strain expressing CYP116B5-SOX was employed to exploit this biocatalyst for the oxidation of the wastewater contaminating-drug tamoxifen. Data show a 12-fold increase in tamoxifen N-oxide production-herein detected for the first time as CYP116B5 metabolite-compared to the direct H2O2 supply, equal to the 25% of the total drug conversion.

Dual-mode fluorescence and colorimetric smartphone-based sensing platform with oxidation-induced self-assembled nanoflowers for sarcosine detection.

BACKGROUND: Early prostatic cancer (PCa) diagnosis significantly improves the chances of successful treatment and enhances patient survival rates. Traditional enzyme cascade-based early cancer detection methods offer efficiency and signal amplification but are limited by cost, complexity, and enzyme dependency, affecting stability and practicality. Meanwhile, sarcosine (Sar) is commonly considered a biomarker for PCa development. It is essential to develop a Sar detection method based on cascade reactions, which should be efficient, low skill requirement, and suitable for on-site testing. RESULTS: To address this, our study introduces the synthesis of organic-inorganic self-assembled nanoflowers to optimize existing detection methods. The Sar oxidase (SOX)-inorganic hybrid nanoflowers (Cu3(PO4)2:Ce@SOX) possess inherent fluorescent properties and excellent peroxidase activity, coupled with efficient enzyme loading. Based on this, we have developed a dual-mode multi-enzyme cascade nanoplatform combining fluorescence and colorimetric methods for the detection of Sar. The encapsulation yield of Cu3(PO4)2:Ce@SOX reaches 84.5 %, exhibiting a remarkable enhancement in catalytic activity by 1.26-1.29 fold compared to free SOX. The present study employing a dual-signal mechanism encompasses 'turn-off' fluorescence signals ranging from 0.5 µM to 60 µM, with a detection limit of 0.226 µM, and 'turn-on' colorimetric signals ranging from 0.18 µM to 60 µM, with a detection limit of 0.120 µM. SIGNIFICANCE: Furthermore, our study developed an intelligent smartphone sensor system utilizing cotton swabs for real-time analysis of Sar without additional instruments. The nano-platform exhibits exceptional repeatability and stability, rendering it well-suited for detecting Sar in authentic human urine samples. This innovation allows for immediate analysis, offering valuable insights for portable and efficient biosensors applicable to Sar and other analytes.

Utility of Triethyloxonium Tetrafluoroborate for Chloride Removal during Sarcosine N-Carboxyanhydride Synthesis: Improving NCA Purity.

The clinical translation of polysarcosine (pSar) as polyethylene glycol (PEG) replacement in the development of novel nanomedicines creates a broad demand of polymeric material in high-quality making high-purity sarcosine N-carboxyanhydride (Sar-NCA) as monomer for its production inevitable. Within this report, we present the use of triethyloxonium tetrafluoroborate in Sar-NCA synthesis with focus on amino acid and chloride impurities to avoid the sublimation of Sar-NCAs. With a view towards upscaling into kilogram or ton scale, a new methodology of monomer purification is introduced by utilizing the Meerwein's Salt triethyloxonium tetrafluoroborate to remove chloride impurities by covalent binding and converting chloride ions into volatile products within a single step. The novel straightforward technique enables access to monomers with significantly reduced chloride content (<100 ppm) compared to Sar-NCA derived by synthesis or sublimation. The derived monomers enable the controlled-living polymerization in DMF and provide access to pSar polymers with Poisson-like molecular weight distribution within a high range of chain lengths (Xn 25-200). In conclusion, the reported method can be easily applied to Sar-NCA synthesis or purification of commercially available pSar-NCAs and eases access to well-defined hetero-telechelic pSar polymers.

The Production of Polysarcosine-Containing Nanoparticles by Ring-Opening Polymerization-Induced Self-Assembly.

N-carboxyanhydride ring-opening polymerization-induced self-assembly (NCA ROPISA) offers a convenient route for generating poly(amino acid)-based nanoparticles in a single step, crucially avoiding the need for post-polymerization self-assembly. Most examples of NCA ROPISA make use of a poly(ethylene glycol) (PEG) hydrophilic stabilizing block, however this non-biodegradable, oil-derived polymer may cause an immunological response in some individuals. Alternative water-soluble polymers are therefore highly sought. This work reports the synthesis of wholly poly(amino acid)-based nanoparticles, through the chain-extension of a polysarcosine macroinitiator with L-Phenylalanine-NCA (L-Phe-NCA) and Alanine-NCA (Ala-NCA), via aqueous NCA ROPISA. The resulting polymeric structures comprise of predominantly anisotropic, rod-like nanoparticles, with morphologies primarily influenced by the secondary structure of the hydrophobic poly(amino acid) that enables their formation.

Polysarcosine as PEG Alternative for Enhanced Camptothecin-Induced Cancer Immunogenic Cell Death.

Nanomedicine-enhanced immunogenic cell death (ICD) has attracted considerable attention for its great potential in cancer treatment. Even though polyethylene glycol (PEG) is widely recognized as the gold standard for surface modification of nanomedicines, some shortcomings associated with this PEGylation, such as hindered cell endocytosis and accelerated blood clearance phenomenon, have been revealed in recent years. Notably, polysarcosine (PSar) as a highly biocompatible polymer can be finely synthesized by mild ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCAs) and exhibit great potential as an alternative to PEG. In this article, PSar-b-polycamptothecin block copolymers are synthesized by sequential ROP of camptothecin-based NCAs (CPT-NCAs) and Sar-NCAs. Then, the detailed and systematic comparison between PEGylation and PSarylation against the 4T1 tumor model indicates that PSar decoration can facilitate the cell endocytosis, greatly enhancing the ICD effects and antitumor efficacy. Therefore, it is believed that this well-developed PSarylation technique will achieve effective and precise cancer treatment in the near future.

Trimethylamine N-oxide, choline and its metabolites are associated with the risk of non-alcoholic fatty liver disease.

It is inconclusive whether trimethylamine N-oxide (TMAO) and choline and related metabolites, namely trimethylamine (TMA), l-carnitine, betaine and dimethylglycine (DMG), are associated with non-alcoholic fatty liver disease (NAFLD). Our objective was to investigate these potential associations. Additionally, we sought to determine the mediating role of TMAO. In this 1:1 age- and sex-matched case-control study, a total of 150 pairs comprising NAFLD cases and healthy controls were identified. According to the fully adjusted model, after the highest tertile was compared with the lowest tertile, the plasma TMAO concentration (OR = 2·02 (95 % CI 1·04, 3·92); P trend = 0·003), l-carnitine concentration (OR = 1·79 (1·01, 3·17); P trend = 0·020) and DMG concentration (OR = 1·81 (1·00, 3·28); P trend = 0·014) were significantly positively associated with NAFLD incidence. However, a significantly negative association was found for plasma betaine (OR = 0. 50 (0·28, 0·88); P trend = 0·001). The restricted cubic splines model consistently indicated positive dose-response relationships between exposure to TMAO, l-carnitine, and DMG and NAFLD risk, with a negative association being observed for betaine. The corresponding AUC increased significantly from 0·685 (0·626, 0·745) in the traditional risk factor model to 0·769 (0·716, 0·822) when TMAO and its precursors were included (l-carnitine, betaine and choline) (P = 0·032). Mediation analyses revealed that 14·7 and 18·6 % of the excess NAFLD risk associated with l-carnitine and DMG, respectively, was mediated by TMAO (the P values for the mediating effects were 0·021 and 0·036, respectively). These results suggest that a higher concentration of TMAO is associated with increased NAFLD risk among Chinese adults and provide evidence of the possible mediating role of TMAO.

[3H]-NFPS binding to the glycine transporter 1 in the hemi-parkinsonian rat brain.

L-3,4-dihydroxyphenylalanine (L-DOPA) is the main treatment for Parkinson's disease (PD) but with long term administration, motor complications such as dyskinesia are induced. Glycine transporter 1 (GlyT1) inhibition was shown to produce an anti-dyskinetic effect in parkinsonian rats and primates, coupled with an improvement in the anti-parkinsonian action of L-DOPA. The expression of GlyT1 in the brain in the dyskinetic state remains to be investigated. Here, we quantified the levels of GlyT1 across different brain regions using [3H]-NFPS in the presence of Org-25,935. Brain sections were chosen from sham-lesioned rats, L-DOPA-naïve 6-hydroxydopamine (6-OHDA)-lesioned rats and 6-OHDA-lesioned rats exhibiting mild or severe abnormal involuntary movements (AIMs). [3H]-NFPS binding decreased in the ipsilateral and contralateral thalamus, by 28% and 41%, in 6-OHDA-lesioned rats with severe AIMs compared to sham-lesioned animals (P < 0.01 and 0.001). [3H]-NFPS binding increased by 21% in the ipsilateral substantia nigra of 6-OHDA-lesioned rats with severe AIMs compared to 6-OHDA-lesioned rats with mild AIMs (P < 0.05). [3H]-NFPS binding was lower by 19% in the contralateral primary motor cortex and by 20% in the contralateral subthalamic nucleus of 6-OHDA-lesioned rats with mild AIMs animals compared to rats with severe AIMs (both P < 0.05). The severity of AIMs scores positively correlated with [3H]-NFPS binding in the ipsilateral substantia nigra (P < 0.05), ipsilateral entopeduncular nucleus (P < 0.05) and contralateral primary motor cortex (P < 0.05). These data provide an anatomical basis to explain the efficacy of GlyT1 inhibitors in dyskinesia in PD.

Serum betaine and dimethylglycine in mid-pregnancy and the risk of gestational diabetes mellitus: a case-control study.

PURPOSE: To investigate the associations of choline, betaine, dimethylglycine (DMG), L-carnitine, and Trimethylamine-N-oxide (TMAO) with the risk of Gestational diabetes mellitus (GDM) as well as the markers of glucose homeostasis. METHODS: We performed a case-control study including 200 diagnosed GDM cases and 200 controls matched by maternal age (±2 years) and gestational age (±2 weeks). Concentrations of serum metabolites were measured by the high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). RESULTS: Compared to the control group, GDM group had significantly lower serum betaine concentration and betaine/choline ratio, and higher DMG concentration. Furthermore, decreased betaine concentration and betaine/choline ratio, increased DMG concentration showed significant association with the risk of GDM. In addition, serum betaine concentrations were negatively associated with blood glucose levels at 1-h post-glucose load (OGTT-1h), and both betaine and L-carnitine concentrations were positively associated with 1,5-anhydroglucitol levels. Betaine/choline ratio was negatively associated with OGTT-1h and blood glucose levels at 2-h post-glucose load (OGTT-2h) and serum choline concentrations were negatively associated with fasting blood glucose and positively associated with OGTT-2h. CONCLUSION: Decreased serum betaine concentrations and betaine/choline ratio, and elevated DMG concentrations could be significant risk factors for GDM. Furthermore, betaine may be associated with blood glucose regulation and short-term glycemic fluctuations.