Liver Fatty Acid Binding Protein Research Articles

A case study of a liver transplant-treated patient with glycogen storage disease type Ia presenting with multiple inflammatory hepatic adenomas: an analysis of clinicopathologic and genetic data

BackgroundGlycogen storage disease (GSD) is a disease caused by excessive deposition of glycogen in tissues due to genetic disorders in glycogen metabolism. Glycogen storage disease type I (GSD-I) is also known as VonGeirk disease and glucose-6-phosphatase deficiency. This disease is inherited in an autosomal recessive manner, and both sexes can be affected. The main symptoms include hypoglycaemia, hepatomegaly, acidosis, hyperlipidaemia, hyperuricaemia, hyperlactataemia, coagulopathy and developmental delay.Case presentationHere, we present the case of a 13-year-old female patient with GSD Ia complicated with multiple inflammatory hepatic adenomas. She presented to the hospital with hepatomegaly, hypoglycaemia, and epistaxis. By clinical manifestations and imaging and laboratory examinations, we suspected that the patient suffered from GSD I. Finally, the diagnosis was confirmed by liver pathology and whole-exome sequencing (WES).WES revealed a synonymous mutation, c.648 G > T (p.L216 = , NM_000151.4), in exon 5 and a frameshift mutation, c.262delG (p.Val88Phefs*14, NM_000151.4), in exon 2 of the G6PC gene. According to the pedigree analysis results of first-generation sequencing, heterozygous mutations of c.648 G > T and c.262delG were obtained from the patient's father and mother.Liver pathology revealed that the solid nodules were hepatocellular hyperplastic lesions, and immunohistochemical (IHC) results revealed positive expression of CD34 (incomplete vascularization), liver fatty acid binding protein (L-FABP) and C-reactive protein (CRP) in nodule hepatocytes and negative expression of β-catenin and glutamine synthetase (GS). These findings suggest multiple inflammatory hepatocellular adenomas. PAS-stained peripheral hepatocytes that were mostly digested by PAS-D were strongly positive.This patient was finally diagnosed with GSD-Ia complicated with multiple inflammatory hepatic adenomas, briefly treated with nutritional therapy after diagnosis and then underwent living-donor liver allotransplantation.After 14 months of follow-up, the patient recovered well, liver function and blood glucose levels remained normal, and no complications occurred.ConclusionThe patient was diagnosed with GSD-Ia combined with multiple inflammatory hepatic adenomas and received liver transplant treatment. For childhood patients who present with hepatomegaly, growth retardation, and laboratory test abnormalities, including hypoglycaemia, hyperuricaemia, and hyperlipidaemia, a diagnosis of GSD should be considered. Gene sequencing and liver pathology play important roles in the diagnosis and typing of GSD.

Drugs Form Ternary Complexes with Human Liver Fatty Acid Binding Protein 1 (FABP1) and FABP1 Binding Alters Drug Metabolism.

Liver fatty acid binding protein 1 (FABP1) binds diverse endogenous lipids and is highly expressed in the human liver. Binding to FABP1 alters the metabolism and homeostasis of endogenous lipids in the liver. Drugs have also been shown to bind to rat FABP1, but limited data are available for human FABP1 (hFABP1). FABP1 has a large binding pocket, and up to two fatty acids can bind to FABP1 simultaneously. We hypothesized that drug binding to hFABP1 results in formation of ternary complexes and that FABP1 binding alters drug metabolism. To test these hypotheses, native protein mass spectrometry (MS) and fluorescent 11-(dansylamino)undecanoic acid (DAUDA) displacement assays were used to characterize drug binding to hFABP1, and diclofenac oxidation by cytochrome P450 2C9 (CYP2C9) was studied in the presence and absence of hFABP1. DAUDA binding to hFABP1 involved high (Kd,1 = 0.2 μM) and low (Kd,2 > 10 μM) affinity binding sites. Nine drugs bound to hFABP1 with equilibrium dissociation constant (Kd) values ranging from 1 to 20 μM. None of the tested drugs completely displaced DAUDA from hFABP1, and fluorescence spectra showed evidence of ternary complex formation. Formation of DAUDA-hFABP1-diclofenac ternary complex was verified with native MS. Docking predicted diclofenac binding in the portal region of FABP1 with DAUDA in the binding cavity. The catalytic rate constant of diclofenac hydroxylation by CYP2C9 was decreased by ∼50% (P < 0.01) in the presence of FABP1. Together, these results suggest that drugs form ternary complexes with hFABP1 and that hFABP1 binding in the liver will alter drug metabolism and clearance. SIGNIFICANCE STATEMENT: Many commonly prescribed drugs bind fatty acid binding protein 1 (FABP1), forming ternary complexes with FABP1 and the fluorescent fatty acid 11-(dansylamino)undecanoic acid. These findings suggest that drugs will bind to apo-FABP1 and fatty acid-bound FABP1 in the human liver. The high expression of FABP1 in the liver, together with drug binding to FABP1, may alter drug disposition processes in vivo.

CYP2C9, CYP3A and CYP2C19 metabolize Δ9-tetrahydrocannabinol to multiple metabolites but metabolism is affected by human liver fatty acid binding protein (FABP1)

Δ9-tetrahydrocannabinol (THC) is the psychoactive constituent of cannabis. It is cleared predominantly via metabolism. Metabolism to 11-OH-THC by cytochrome P450 (CYP) 2C9 has been proposed as the main clearance pathway of THC, with the estimated fraction metabolized (fm) about 70%. The remaining clearance pathways are not well established, and it is unknown how THC is eliminated in individuals with reduced CYP2C9 activity. The goal of this study was to systematically identify the CYP enzymes contributing to THC clearance and characterize the metabolites formed. Further, this study aimed to characterize the impact of liver fatty acid binding protein (FABP1) on THC metabolism by human CYPs. THC was metabolized to at least four different metabolites including 11-OH-THC in human liver microsomes (HLMs) and with recombinant CYPs. 11-OH-THC was formed by recombinant CYP2C9 (Km,u = 0.77 nM, kcat = 12 min−1) and by recombinant CYP2C19 (Km,u = 2.2 nM, kcat = 14 min−1). The other three major metabolites were likely hydroxylations in the cyclohexenyl ring and were formed mainly by recombinant CYP3A4/5 (Km,u > 10 nM). HLM experiments confirmed the contributions of CYP2C9, CYP2C19 and CYP3A to THC metabolism. The presence of FABP1 and THC binding to FABP1 altered THC metabolism by recombinant CYPs and HLMs in an enzyme and metabolite specific manner. This suggests that FABP1 may interact with CYP enzymes and alter the fm by CYPs towards THC metabolism. In conclusion, this study is the first to systematically establish the metabolic profile of THC by human CYPs and characterize how FABP1 binding alters CYP mediated THC metabolism.

Study of fatty acid-binding protein and Bacteroidetes and Firmicutes levels in patients with metabolic-associated fatty liver disease in combination with type 2 diabetes mellitus and small intestinal bacterial overgrowth syndrome

The aim of the study was to examine serum levels of liver and intestinal fatty acid-binding proteins (L-FABP and I-FABP), fecal numbers of Bacteroidetes (B) and Firmicutes (F) in patients with metabolic-associated fatty liver disease (MAFLD) in combination with type 2 diabetes mellitus (Т2DM) and small intestinal bacterial overgrowth (SIBO) syndrome. Materials and methods. The prospective, interventional, randomized study included 51 patients with MAFLD in combination with Т2DM, who were examined and divided into 2 groups. Group 1 consisted of 24 patients with MAFLD and Т2DM without SIBO. Group 2 was comprised of 27 patients with MAFLD in combination with Т2DM and SIBO. The control group included 20 apparently healthy individuals. Serum levels of L-FABP and I-FABP were measured by ELISA method using the Human L-FABP and I-FABP ELISA Kit test systems, respectively (Elabscience, USA). Fecal numbers of B and F were determined by real-time PCR. Bacterial DNA was detected in a thermal cycler Rotor-Gene 6000 (QIAGEN, Germany) using DNA 16S rRNA primers and NanoDrop ND-8000 reagents (Thermo Scientific, USA). Results. To assess the state of intestinal permeability, serum levels of L-FABP and I-FABP were examined and numbers of phylum F and В as well as their ratio were calculated. Patients of both groups have been found to have increased serum levels of L-FABP, I-FABP, numbers of B in fecal samples and decreased numbers of F and F/B ratio. Conclusions. The study results obtained have revealed increased intestinal permeability and demonstrated an important diagnostic value of serum L-FABP and I-FABP as a biomarker of intestinal permeability in diabetic MAFLD patients with or without SIBO. Increased fecal numbers of Bacteroidetes, decreased numbers of Firmicutes and F/B ratio have been detected in diabetic MAFLD patients with or without SIBO.

Comparative quantitation of liver-type fatty acid-binding protein localizations in liver injury and non-pathological liver tissue in dogs

Background and Aim: Liver injury results in the production of free radicals that can lead to hepatocytic degeneration, cirrhosis, and hepatocellular carcinoma (HCC). Liver-fatty acid-binding protein (L-FABP) is highly expressed in hepatocytes and is a key regulator of hepatic lipid metabolism and antioxidant characteristics. Interestingly, the increase in L-FABP expression could be used as a novel marker of liver injury. Therefore, this study aimed to use immunohistochemical techniques to investigate the expression of L-FABP in dogs with liver injury compared with dogs with non-pathological liver. Materials and Methods: Liver tissue samples were collected from dog biopsy specimens at the Veterinary Diagnostic Laboratory at the Faculty of Veterinary Medicine, Chiang Mai University. The tissues were prepared for immunohistochemistry and the expression and localization of L-FABP were investigated using one-way analysis of variance. Results: Immunohistochemical analysis showed that L-FABP was strongly expressed in the hepatocytes of dogs with lipidosis and HCC when compared with that in normal liver. Semi-quantitative immunohistochemistry evaluation showed the percentage of protein expression of L-FABP 0.023 ± 0.027 in the non-pathological liver. The percentage of L-FABP protein expression in lipidosis and HCC was found to be 8.517 ± 1.059 and 17.371 ± 4.026, respectively. Conclusion: L-FABP expression in dogs with liver injuries was significantly higher than that in dogs with non-pathological liver injury (p = 0.05). These results suggest that L-FABP has the potential as a novel marker for specific diagnosis and prognosis of dogs with liver injury. Keywords: canine, hepatocyte, immunohistochemistry, lipidosis, liver injury, liver-fatty acid-binding protein, pathology.

The Comparative Effects of Supplementing Protease Combined with Carbohydrase Enzymes on the Performance and Egg n-3 Deposition of Laying Hens Fed with Corn-Flaxseed or Wheat-Flaxseed Diets.

Flaxseed contains huge quantities of anti-nutritional factors (ANFs), which reduce the performance of livestock. Three different protease and multi-carbohydrase enzymes were included in wheat-flaxseed diets (WFD) and corn-flaxseed diets (CFD) to compare their effects on performance, egg n-3 deposition, and fatty acid transporter genes in laying hens. A total of 540, twenty-week-old, Nongda-3 laying hens (DW brown × Hy-line white) were randomly assigned to six dietary groups, including 10% WFD or 10% CFD plus (i) supplemental enzyme A (alkaline protease 40,000 and neutral protease 10,000 (U/g)), (ii) enzyme B (alkaline protease 40,000, neutral protease 10,000, and cellulase 4000 (U/g)), or iii) enzyme C (neutral protease 10,000, xylanase 35,000, β-mannanase 1500, β-glucanase 2000, cellulose 500, amylase 100, and pectinase 10,000 (U/g)). An interaction (p < 0.05) was found for egg mass, hen day of egg production, and feed conversion ratio on the 9-10th week of the experiment. The WFD with enzyme B was associated with the highest egg weight in the 9-10th week. The deposition of total n-3 was superior with WFD (468.22 mg/egg) compared to CFD (397.90 mg/egg), while addition of enzyme C (464.90 mg/egg) resulted in the deposition of more total n-3 compared to enzymes A and B (411.89 and 422.42 mg/egg). The WFD and enzyme C significantly (p < 0.001) enhanced docosahexaenoic acid (DHA) and reduced the n-6:n-3 ratio in egg yolk compared to the CFD. The hepatic mRNA expression of liver fatty acid binding protein (L-FABP) (p = 0.006), fatty acid desaturase 1 (FADS-1) (p < 0.001), elongase-2 (ELOV-2) (p < 0.001), fatty acid transport protein-1 (FATP1) (p < 0.001), and the intestinal mRNA expression of FATP and FABP genes were increased with WFD compared to CFD. In conclusion, WFD with enzyme C is favorable for optimal performance, results in the deposition of more n-3 and DHA, and increases the expression of fatty acid transporter genes, which helps in n-3 transport.

Investigation of gastrointestinal injury-related biomarkers in dairy cattle with displaced abomasum.

Displaced abomasum (DA) is one of the most important metabolic disorders of dairy cattle. In DA, ischaemic damage may occur as a result of impaired perfusion due to abomasal displacement, which may result in gastrointestinal mucosal damage. Investigation of gastrointestinal tissue damage in cattle with right displacement of the abomasum (RDA) and left displacement of the abomasum (LDA) using intestinal-related biomarkers. Forty-eight DA (24 LDA, 24 RDA) and 15 healthy Holstein dairy cows were enrolled between March 2021 and July 2022. Serum biomarkers including gamma-enteric smooth muscle actin (ACTG-2), liver-fatty acid binding proteins (L-FABP), platelet activating factor (PAF), trefoil factor-3 (TFF-3), leptin, claudin-3 and interleukin-8 (IL-8) concentrations were measured from venous blood samples. L-FABP concentrations in the LDA group and TFF-3 concentrations in the RDA group were lower than in the control group. The leptin concentration of the RDA group was higher than that of the other groups. There was a negative correlation between lactate, leptin and IL-8 concentrations. There was a negative correlation between lactate and TFF-3, whereas leptin and lactate were positively correlated. Leptin was the more reliable biomarker for discriminating between RDA and LDA cases. Changes in serum L-FABP, TFF-3 and leptin concentrations in cattle with DA may reflect acute intestinal injury and the subsequent repair phase. However, these biomarkers had poor diagnostic performance in discriminating between healthy and cattle with DA, while leptin emerged as the most useful marker in differentiating LDA from RDA cases.

A genetically-encoded biosensor for direct detection of perfluorooctanoic acid

Determination of per- and polyfluoroalkyl substances (PFAS) in drinking water at the low levels set by regulatory officials has been a major focus for sensor developing researchers. However, it is becoming more apparent that detection of these contaminants in soils, foods and consumer products is relevant and necessary at part per billion and even part per million levels. Here, a fluorescent biosensor for the rapid detection of PFOA was engineered based on human liver fatty acid binding protein (hLFABP). By conjugating circularly permuted green fluorescent protein (cp.GFP) to a split hLFABP construct, the biosensor was able to detect perfluorooctanoic acid PFOA in PBS as well as environmental water samples with LODs of 236 and 330 ppb respectively. Furthermore, E. coli cells cytosolically expressing the protein-based sensor were demonstrated to quickly detect PFOA, demonstrating feasibility of whole-cell sensing. Overall, this work demonstrates a platform technology utilizing a circularly permuted GFP and split hLFABP conjugate as a label-free optical biosensor for PFOA.

Subclinical and clinical acute kidney injury share similar urinary peptide signatures and prognosis.

Acute kidney injury (AKI) is a frequent and severe condition in intensive care units (ICUs). In 2020, the Acute Dialysis Quality Initiative (ADQI) group proposed a new stage of AKI, referred to as stage 1S, which represents subclinical disease (sAKI) defined as a positive biomarker but no increase in serum creatinine (sCr). This study aimed to determine and compare the urinary peptide signature of sAKI as defined by biomarkers. This is an ancillary analysis of the prospective, observational, multinational FROG-ICU cohort study. AKI was defined according to the Kidney Disease Improving Global Outcome definition (AKIKDIGO). sAKI was defined based on the levels of the following biomarkers, which exceeded the median value: neutrophil gelatinase-associated lipocalin (pNGAL, uNGAL), cystatin C (pCysC, uCysC), proenkephalin A 119-159 (pPENKID) and liver fatty acid binding protein (uLFABP). Urinary peptidomics analysis was performed using capillary electrophoresis-mass spectrometry. Samples were collected at the time of study inclusion. One thousand eight hundred eighty-five patients had all biomarkers measured at inclusion, which included 1154 patients without AKI (non-AKIKDIGO subgroup). The non-AKIKDIGO subgroup consisted of individuals at a median age of 60 years [48, 71], among whom 321 (27.8%) died. The urinary peptide signatures of sAKI, regardless of the biomarkers used for its definition, were similar to the urinary peptide signatures of AKIKDIGO (inflammation, haemolysis, and endothelial dysfunction). These signatures were also associated with 1-year mortality. Biomarker-defined sAKI is a common and severe condition observed in patients within intensive care units with a urinary peptide signature that is similar to that of AKI, along with a comparable prognosis.

Disclosing Environmental Ligands of L-FABP and PPARγ: Should We Re-evaluate the Chemical Safety of Hydrocarbon Surfactants?

Chemical contaminants can cause adverse effects by binding to the liver-fatty acid binding protein (L-FABP) and peroxisome proliferator-activated nuclear receptor γ (PPARγ), which are vital in lipid metabolism. However, the presence of numerous compounds in the environment has hindered the identification of their ligands, and thus only a small portion have been discovered to date. In this study, protein Affinity Purification with Nontargeted Analysis (APNA) was employed to identify the ligands of L-FABP and PPARγ in indoor dust and sewage sludge. A total of 83 nonredundant features were pulled-out by His-tagged L-FABP as putative ligands, among which 13 were assigned as fatty acids and hydrocarbon surfactants. In contrast, only six features were isolated when His-tagged PPARγ LBD was used as the protein bait. The binding of hydrocarbon surfactants to L-FABP and PPARγ was confirmed using both recombinant proteins and reporter cells. These hydrocarbon surfactants, along with >50 homologues and isomers, were detected in dust and sludge at high concentrations. Fatty acids and hydrocarbon surfactants explained the majority of L-FABP (57.7 ± 32.9%) and PPARγ (66.0 ± 27.1%) activities in the sludge. This study revealed hydrocarbon surfactants as the predominant synthetic ligands of L-FABP and PPARγ, highlighting the importance of re-evaluating their chemical safety.

Hepatotoxicity assessment investigations on PFASs targeting L-FABP using binding affinity data and machine learning-based QSAR model

Per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants that have been detected in various environmental media and human serum, but their safety assessment remains challenging. PFASs may accumulate in liver tissues and cause hepatotoxicity by binding to liver fatty acid binding protein (L-FABP). Therefore, evaluating the binding affinity of PFASs to L-FABP is crucial in assessing the potential hepatotoxic effects. In this study, two binding sites of L-FABP were evaluated, results suggested that the outer site possessed high affinity to polyfluoroalkyl sulfates and the inner site preferred perfluoroalkyl sulfonamides, overall, the inner site of L-FABP was more sensitive to PFASs. The binding affinity data of PFASs to L-FABP were used as training set to develop a machine learning model-based quantitative structure-activity relationship (QSAR) for efficient prediction of potentially hazardous PFASs. Further Bayesian Kernel Machine Regression (BKMR) model disclosed flexibility as the determinant molecular property on PFASs-induced hepatotoxicity. It can influence affinity of PFASs to target protein through affecting binding conformations directly (individual effect) as well as integrating with other molecular properties (joint effect). Our present work provided more understanding on hepatotoxicity of PFASs, which could be significative in hepatotoxicity gradation, administration guidance, and safer alternatives development of PFASs.

Derlin-1 ameliorates nonalcoholic hepatic steatosis by promoting ubiquitylation and degradation of FABP1

Background and aimsThe functions of liver fatty acid binding protein 1 (FABP1) in the regulation of nonalcoholic fatty liver disease (NAFLD) have been previously established. However, how FABP1 expression is dynamically regulated in metabolic disorders is unclear. Previous studies have reported that ubiquitin proteasome-mediated degradation of FABP1 is involved, but the mechanism remains unknown. MethodsDysregulated expression of hepatic FABP1 and Derlin-1 was observed in NAFLD patients. We performed mice hepatic tissue coimmunoprecipitation based mass spectrum assays. Interaction between Derlin-1 and FABP1, and its impact on FABP1 ubiquitination status was evaluated by coimmunoprecipitation. The role of Derlin-1 in lipid deposition was tested using adenovirus-mediated overexpression in C57BL/6 mice, as well as by Derlin-1 overexpression or knockdown in HepG2 cells. ResultsAs a subunit of the endoplasmic reticulum-associated degradation complex, Derlin-1 was negatively associated with NAFLD patients, interacted with and ubiquitinated FABP1. Derlin-1 suppressed FABP1 levels and inhibited lipid deposition through a FABP1-dependent pathway. Additionally, Trim25, an E3 ubiquitin ligase present in the endoplasmic reticulum, was recruited to promote Derlin-1-related polyubiquitylation of FABP1, thereby creating a ubiquitin-associated network for FABP1 regulation. Derlin-1 overexpression ameliorated hepatic steatosis in both C57BL/6 mice and HepG2 cells, and contributed to attenuated weight gain, lower liver weight, and visceral fat mass. ConclusionsFABP1 was degraded by Derlin-1 through ubiquitin modification. Negative regulation of FABP1 by Derlin-1 overexpression, suppressed lipid metabolism and alleviated lipid deposition in vivo and in vitro. Hence, Derlin-1 activation in hepatocytes may represent a potential therapeutic strategy for NAFLD.

Serum TGF-β1 and CD14 Predicts Response to Anti-TNF-α Therapy in IBD.

Tumor necrosis factor-alpha (TNF-α) agonists revolutionized therapeutic algorithms in inflammatory bowel disease (IBD) management. However, approximately every third IBD patient does not respond to this therapy in the long term, which delays efficient control of the intestinal inflammation. We analyzed the power of serum biomarkers to predict the failure of anti-TNF-α. We collected serum of 38 IBD patients at therapy prescription and 38 weeks later and analyzed them with relation to therapy response (no-, partial-, and full response). We used enzyme-linked immunosorbent assay to quantify 16 biomarkers related to gut barrier (intestinal fatty acid-binding protein, liver fatty acid-binding protein, trefoil factor 3, and interleukin (IL)-33), microbial translocation, immune system regulation (TNF-α, CD14, lipopolysaccharide-binding protein, mannan-binding lectin, IL-18, transforming growth factor-β1 (TGF-β1), osteoprotegerin (OPG), insulin-like growth factor 2 (IGF-2), endocrine-gland-derived vascular endothelial growth factor), and matrix metalloproteinase system (MMP-9, MMP-14, and tissue inhibitors of metalloproteinase-1). We found that future full-responders have different biomarker profiles than non-responders, while partial-responders cannot be distinguished from either group. When future non-responders were compared to responders, their baseline contained significantly more TGF-β1, less CD14, and increased level of MMP-9, and concentration of these factors could predict non-responders with high accuracy (AUC = 0.938). Interestingly, during the 38 weeks, levels of MMP-9 decreased in all patients, irrespective of the outcome, while OPG, IGF-2, and TGF-β1 were higher in non-responders compared to full-responders both at the beginning and the end of the treatment. The TGF-β1 and CD14 can distinguish non-responders from responders. The changes in biomarker dynamics during the therapy suggest that growth factors (such as OPG, IGF-2, and TGF-β) are not markedly influenced by the treatment and that anti-TNF-α therapy decreases MMP-9 without influencing the treatment outcome.

Liver Fatty Acid-binding Protein (L-FABP) as a Diagnostic Marker for Non-alcoholic Fatty Liver Disease

Liver Fatty Acid-binding Protein (L-FABP) as a Diagnostic Marker for Non-alcoholic Fatty Liver Disease

Rapid and ultrasensitive detection of acute kidney injury biomarkers CH3L1 and L-FABP using surface-enhanced Raman spectroscopy

Chitinase 3-like 1 (CH3L1) and liver fatty acid binding protein (L-FABP) are promising biomarkers for the early diagnosis of acute kidney injury (AKI). Here, a highly sensitive method for the quantitative detection of CH3L1 and L-FABP by surface-enhanced Raman spectroscopy (SERS) based on graphene oxide/gold and silver core–shell nanoparticles (GO/Au@Ag NPs) was proposed. The results showed that such GO/Au@Ag substrate can achieve rapid sensing of CH3L1 and L-FABP with a wide response range (2 × 10-1 to 2 × 10-8 mg/mL and 1.2 × 10-1 to 1.2 × 10-8 mg/mL, respectively) and high sensitivity. The detection limits of CH3L1 and L-FABP were 1.21 × 10-8 mg/mL and 0.62 × 10-8 mg/mL, respectively. In addition, the simultaneous detection of the two biomarkers in serum was demonstrated, showing the feasibility of this method in the complex biological environment. The detection of CH3L1 and L-FABP will greatly improve the early diagnosis and intervention of AKI.

From Protein Sequence to Structure: The Next Frontier in Cross-Species Extrapolation for Chemical Safety Evaluations.

Computational screening for potentially bioactive molecules using advanced molecular modeling approaches including molecular docking and molecular dynamic simulation is mainstream in certain fields like drug discovery. Significant advances in computationally predicting protein structures from sequence information have also expanded the availability of structures for nonmodel species. Therefore, the objective of the present study was to develop an analysis pipeline to harness the power of these bioinformatics approaches for cross-species extrapolation for evaluating chemical safety. The Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool compares protein-sequence similarity across species for conservation of known chemical targets, providing an initial line of evidence for extrapolation of toxicity knowledge. However, with the development of structural models from tools like the Iterative Threading ASSEmbly Refinement (ITASSER), analyses of protein structural conservation can be included to add further lines of evidence and generate protein models across species. Models generated through such a pipeline could then be used for advanced molecular modeling approaches in the context of species extrapolation. Two case examples illustrating this pipeline from SeqAPASS sequences to I-TASSER-generated protein structures were created for human liver fatty acid-binding protein (LFABP) and androgen receptor (AR). Ninety-nine LFABP and 268 AR protein models representing diverse species were generated and analyzed for conservation using template modeling (TM)-align. The results from the structural comparisons were in line with the sequence-based SeqAPASS workflow, adding further evidence of LFABL and AR conservation across vertebrate species. The present study lays the foundation for expanding the capabilities of the web-based SeqAPASS tool to include structural comparisons for species extrapolation, facilitating more rapid and efficient toxicological assessments among species with limited or no existing toxicity data. Environ Toxicol Chem 2023;42:463-474. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Chemiluminescence Immunoassay Method of Urinary Liver Fatty-acid-binding Protein as a Promising Candidate for Kidney Disease.

Liver fatty acid binding protein (L-FABP) is an intercellular lipid chaperone protein that selectively combines with unsaturated free fatty acids and transports them to mitochondria or peroxisomes. L-FABP is a promising biomarker for the early detection of renal diseases in humans. Herein a chemiluminescence method (CLIA) was demonstrated to measure the level of urinary L-FABP in the urinary samples. An anti-(L-FABP)-magnetic beads complex was prepared to capture the analyte target. Sensitivity, precision, accuracy, interference effect, high-dose hook effect of the developed assay were evaluated. Under the suitable experimental parameters, the established method have a wide linear range (0.01-10ng/mL) and also showed a sufficiently low limit of detection of 0.0060ng/mL. Besides, the satisfactory recoveries of the method in the urinary were ranged from 97.74%-112.32%, which was well within the requirement of clinical analysis. Furthermore, this proposed method has been successfully applied to the clinical determination of L-FABP in patients who have been diagnosed with kidney disease. The results showed that CLIA could accurately and rapidly determine the urinary level of L-FABP with high-throughput, which could be useful as a new tool to predict complications in patients with kidney disease. The clinical trial was approved by Shuyang Hospital of Traditional Chinese Medicine Ethics Committee: 20,210,202-001 at February 2, 2021.

Omega-3 meat enrichment and L-FABP, PPARA, and LPL genes expression are modified by the level and period of tuna oil supplementation in slow-growing chickens.

This study proposes a strategy to manipulate the fatty acid (FA) content in slow-growing Korat chicken (KRC) meat using tuna oil (TO). To determine the optimal level and feeding period of TO supplementation, we conducted a study investigating the effects of dietary TO levels and feeding periods on meat quality, omega-3 polyunsaturated fatty acid (n-3 PUFA) composition, and gene expression related to FA metabolism in KRC breast meat. At 3 wk of age, 700 mixed-sex KRC were assigned to seven augmented factorial treatments with a completely randomized design, each consisting of four replicate pens containing 25 chickens per pen. The control group received a corn-soybean-based diet with 4.5% rice bran oil (RBO), while varying amounts of TO (1.5%, 3.0%, or 4.5%) replaced a portion of the RBO content in the experimental diets. The chickens were fed these diets for 3 and 6 wk, respectively, before being slaughtered at 9 wk. Our results indicated no significant interactions between TO levels and feeding periods on the growth performance or meat quality of KRC (P > 0.05). However, the liver fatty acid-binding protein gene (L-FABP, also known as FABP1), responsible for FA transport and accumulation, showed significantly higher expression in the chickens supplemented with 4.5% TO (P < 0.05). The chickens supplemented with 4.5% TO for a longer period (3 to 9 wk of age) exhibited the lowest levels of n-6 PUFA and n-6 to n-3 ratio, along with the highest levels of eicosapentaenoic acid, docosahexaenoic acid, and n-3 PUFA in the breast meat (P < 0.05). However, even a short period of supplementation with 4.5% TO (6 to 9 wk of age) was adequate to enrich slow-growing chicken meat with high levels of n-3 PUFA, as recommended previously. Our findings indicated that even a short period of tuna oil supplementation could lead to desirable levels of omega-3 enrichment in slow-growing chicken meat. This finding has practical implications for the poultry industry, providing insights into optimal supplementation strategies for achieving desired FA profiles without adversely affecting growth performance or meat quality.

L-FABP and NGAL are novel biomarkers for detection of abdominal injury and hemorrhagic shock

IntroductionDelayed diagnosis of abdominal injuries and hemorrhagic shock leads to secondary complications and high late mortality in severely traumatized patients. The liver fatty acid-binding protein (L-FABP) is expressed in intestine, liver and kidney; the neutrophil gelatinase-associated lipocalin (NGAL) in colon and kidney. We hypothesized that l-FABP is an early biomarker for abdominal injury and hemorrhagic shock and that l-FABP and NGAL are specific markers for detection of liver and/or kidney injuries. Patients and MethodsTraumatized patients with an age ≥18 years and an abdominal injury (AISabd≥2), independently from Injury Severity Score (ISS), were prospectively included from 04/2018 to 05/2021. 68 patients had an abdominal injury (“Abd”) and 10 patients had an abdominal injury with hemorrhagic shock (“HS Abd”). 41 patients without abdominal injury and hemorrhagic shock but with an ISS ≥ 25 (“noAbd”) were included as control group. Four abdominal subgroups with isolated organ injuries were defined. Plasma l-FABP and NGAL levels were measured at admission (ER) and up to two days post-trauma. ResultsAll patient groups had a median ISS≥25. In ER, median l-FABP levels were significantly higher in “HS Abd” group (1209.2 ng/ml [IQR=575.2–1780.3]) compared to “noAbd” group (36.4 ng/ml [IQR=14.8–88.5]), and to “Abd” group (41.4 ng/ml [IQR=18.0–235.5]), p<0.001. In matched-pair-analysis l-FABP levels in the group “Abd” were significantly higher (108.3 ng/ml [IQR=31.4–540.9]) compared to “noAbd” (26.4 ng/ml [IQR=15.5–88.8]), p = 0.0016. l-FABP correlated significantly with clinical parameters of hemorrhagic shock; the optimal cut-off level of l-FABP for detection was 334.3 ng/ml (sensitivity: 90%, specificity: 78%). Median l-FABP-levels were significantly higher in patients with isolated liver or kidney injuries and correlated significantly with AST, ALT and creatinine value. Median NGAL levels in the ER were significantly higher in “HS Abd” group (115.9 ng/ml [IQR=90.6–163.8]) compared to “noAbd” group (58.5 ng/ml [IQR=41.0–89.6],p<0.001) and “Abd” group (70.5 ng/ml [IQR=53.3–115.5], p<0.05). The group “Abd” showed significant higher median NGAL levels compared to “noAbd”, p = 0.019. NGAL levels correlated significantly with clinical parameters of hemorrhagic shock. Conclusion:L-FABP and NGAL are novel biomarkers for detection of abdominal trauma and hemorrhagic shock. l-FABP may be a useful and promising parameter in diagnosis of liver and kidney injuries, NGAL failed to achieve the same.

Dihydroartemisinin engages liver fatty acid binding protein and suppresses metastatic hepatocellular carcinoma growth.

Dihydroartemisinin non-covalently binds liver fatty acid binding protein (FABP1) with micromolar affinity, acts as a FABP1-dependent peroxisome proliferator-activated receptor alpha agonist and inhibits metastatic hepatocellular carcinoma growth.