FABP4 Levels Research Articles

Assessment of Serum FABP-4 Levels in Hypothyroidism Patients: A Comparative Analysis With a Control Group and Their Correlation With Liver Function Tests and Biochemical Factors.

The association of serum FABP4 and other biochemical-related parameters is important to determine complications of hypothyroidism. This study aimed to evaluate serum FABP-4 levels in hypothyroidism patients in comparison with a control group. Forty-five patients with hypothyroidism and 45 healthy volunteers were included in this study. Liver function tests, thyroid hormones panel, lipid profile and serum FABP-4 levels were measured and compared in both groups, and their correlations were analysed. Serum FABP-4 levels were significantly higher in patients with hypothyroidism compared to the control group (p = 0.002), and serum FABP-4 level in males was higher than it in females (p = 0.022). There was a significant difference between patients with hypothyroidism and the control group in the levels of AST (p = 0.012). Moreover, serum FABP-4 levels were negatively correlated with age (p = 0.016) and positively correlated with weight (p = 0.044). In our study, there was a notable increase in serum FABP-4 concentration among hypothyroidism subjects. The data suggest that FABP-4 could potentially be a superior diagnostic indicator for hypothyroidism when contrasted with a control cohort in future studies.

Semaglutide modulates pro-inflammatory neutrophil phenotype induced by supraphysiological levels of the adipokine FABP4 in patients with cardiovascular disease

Abstract Background Increased adiposity is a risk factor for cardiovascular disease (CVD). Adipose tissue is an endocrine organ that releases proteins with pro-inflammatory effects. One of them is FABP4, which levels are increased after adipogenesis. Insulin resistance is linked to supraphysiological levels of this biomarker. Therapies to reduce body weight and improve insulin response, such as the GLP-1 receptor agonists, like semaglutide, have been shown to benefit patients with CVD and obesity, who have a high pro-inflammatory neutrophil profile. Purpose To study the FABP4 effects on neutrophils from patients with cardiovascular disease and cellular models and its possible modulation by semaglutide. Methods We included 11 patients undergoing open heart surgery. Neutrophils from blood were isolated by single-step centrifugation, counted, and same number were treated with FABP4 (100 ng/mL), semaglutide (1nM) or both. Finally, their phenotype was assessed using flow cytometry (FACS). The same treatment conditions were used on differentiated HL-60 cells (dHL-60) to test their phenotype and functionality based on a) oxidative burst capacity using dihydrorhodamine 123 and b) adhesion to coronary artery endothelial cells. At the end, neutrophils phenotype was tested on patients with obesity and diabetes under semaglutide treatment for 6 months, according to clinical practice. Neutrophils phenotype was determined by FACS and FABP4/C5a plasma levels by immunofluorescence assay. Results FABP4 reduced neutrophils’ CD88 (p=0.006) and CXCR2 (p=0.02) levels. This was also verified in dHL60 cells (p=0.01). In these cells, we were also able to observe a CD11b increment after FABP4 treatment (p=0.04), modulated by semaglutide (p=0.02). This phenotype increased the neutrophil-coronary adhesion (p=0.03). Their oxidative burst capacity was attenuated after semaglutide treatment. In addition, 32% of patients underwent semaglutide treatment reduced plasmatic FABP4 (p=0.03) levels and increased CD88 (p=0.01). We confirmed that CD88 modulation does not lead to a change in plasma C5a. Conclusions High FABP4 levels reduce CD88 of neutrophils from patients with cardiovascular disease and enhance their adhesion to coronary endothelial cells. Modulation of the FABP4 effects by semaglutide treatment might suggest a protective mechanism against adiposity/coronary endothelial inflammation.

CSTB, FABP4, IBP-1 and ST2 are strong predictors of mortality after transcatheter edge-to-edge mitral valve repair

Abstract Introduction Various clinical characteristics have emerged as prognostic factors in patients undergoing transcatheter edge-to-edge mitral valve repair (M-TEER). The use of biomarkers for outcome prediction has enormous potential. The goal of this study was to identify novel biomarkers linked with adverse events after M-TEER. Methods We prospectively included 242 patients undergoing M-TEER at our center and obtained pre-procedural blood samples for biomarker analysis. Additionally, 94 follow-up samples were taken three months after M-TEER. A commercial multiplex protein assay (Cardiovascular III, Olink, Uppsala, Sweden) was used to quantify expression levels of 92 defined biomarkers. We analyzed differences in biomarker expression levels between patients that had died within one year after M-TEER and patients that had survived. Results 39 patients (16.3%) had died within one year after M-TEER. In these patients the most significantly upregulated biomarkers were NT-proBNP (expression 3.0-fold compared to survivors, p < 0.001), Cystatin B (CSTB; 2.0-fold, p < 0.001), fatty acid binding protein 4 (FABP4; 2.0-fold, p < 0.001), insulin-like growth factor-binding protein 1 (IBP-1; 1.9-fold, p < 0.001) and suppression of tumourigenicity 2 (ST2; 1.7-fold, p < 0.001). In non-survivors, expression levels of NT-proBNP (6.1-fold, p = 0.036), CSTB (3.2-fold, p = 0.050), FABP4 (3.7-fold, p = 0.037) and ST2 (2.1-fold, p = 0.017) were persistently elevated at the time of follow-up. Since its prognostic impact has already been described elsewhere, NT-proBNP was excluded from further analysis. Kaplan Meier analysis for 1-year mortality was carried out using tertiles of the respective biomarker expression levels. Mortality risk increased significantly with rising expression levels (CSTB: 3.4% in tertile 1, 12.2% in tertile 2, 37.9% in tertile 3; FABP4: 5.1%, 14.2% and 31.7%; IBP-1: 3.3%, 13.2% and 36.2%; ST2: 4.9%, 11.9% and 36.7%; p by log-rank-test < 0.001 for all biomarkers). Patients in which all 4 biomarkers were elevated to the highest tertile had an excessively high mortality risk of 52.9 vs. 13.5% (p by log-rank-test < 0.001). Receiver operating characteristic (ROC) analysis suggested higher predictive performances for mortality of all 4 biomarkers as compared to the EuroSCORE II (CSTB: area under the curve (AUC) 78.1%, 95% CI 70.7 – 85.5%; FABP4: AUC 71.6%, 95% CI 63.1 – 80.0%; IBP-1: AUC 73.9%, 95% CI 65.7 – 82.1%; ST2: AUC 76.2%, 95% CI 68.5 – 84.0%; EuroSCORE II: AUC 68.4%, 95% CI 59.3 – 77.5%). Conclusion This analysis has revealed novel biomarkers (CSTB, FABP4, IBP-1, ST2), which so far have not been characterized in M-TEER and suggests significant prognostic implications. Predictive performance of each of the respective biomarkers was superior to the most commonly used pre-operative risk stratification tool: the surgical EuroSCORE II. This hypothesis-generating study warrants further examination of these promising biomarkers.

Assessment of Intestinal Free Fatty Acid Binding Protein 4 in Alopecia Areata Patients

Introduction: Alopecia areata (AA) is an immune-mediated disease characterized by non-scaring hair loss. High levels of FABP4 have been implicated in different inflammatory diseases. We aim to assess and correlate the level of FABP4 in AA patients and compare with healthy controls. Methods: Eighty-Eight subjects enrolled subdivided equally into AA and healthy controls. AA patients were classified according to the severity and pattern of the disease. The concentration level of FABP4 in serum was assessed and compared to healthy controls using ELISA. Results: The level of FABP4 tends to increase in AA patients than controls with a significant difference (p = 0.0001).There were no statistically significant differences between FABP4 and gender, history, family history, related diseases, or prior treatments. There is a high significant difference between patients with relapse and progressive patients with p = 0.037. Also patients with positive effects in other body sites have higher FABP4 levels than patients without infection in other sites with p = 0.05. The level of FABP4 tends to increase with the severity of the patients. Findings show that there are positive correlations between FABP4 and (disease duration; number of attacks; SALT Score) with r = 0.45, p = 0.0021; r = 0.41, p = 0.007, and r = 0.88, p < 0.0001, respectively. Conclusion: Elevation of FABP4 in serum may correlate with disease severity and could play a vital role in the diagnosis of AA.

Integrative transcriptomics and lipidomics unravels the amelioration effects of Radix Bupleuri on non-alcoholic fatty liver disease

Ethnopharmacological relevanceRadix Bupleuri (Bupleurum chinense DC.) is the most commonly used traditional Chinese medicine (TCM) for the treatment of liver diseases. While the effects of Radix Bupleuri (BR) on lipid-lowering and liver protection have been established, its role in the development of non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet remains unclear. Aim of the studyThe objective of this study was to evaluate the alleviation effects of the active fraction of BR on NAFLD in vivo and to explore the underlying mechanisms through an analysis of liver transcriptome and lipidomics. Materials and methodsThe NAFLD model was established in SD rats by administering a high-fat diet (HFD) for 8 weeks. Subsequently, the NAFLD model rats were continuously gavaged with different polarity fractions of BR (25 g/kg/d) and melatonin (MT) (30 mg/kg/d) for an additional 6 weeks to assess therapeutic effects. The potential mechanism of the low polarity fraction of BR (LBR) in treating NAFLD was investigated through hepatic transcriptome analysis, non-targeted lipidomics, RT-qPCR, protein-protein interaction (PPI) network construction, molecular docking, and Western blotting, aiming to elucidate the underlying mechanisms by which LBR may ameliorate NAFLD. ResultsThese results demonstrated that LBR significantly alleviated the effects of HFD-induced NAFLD, as evidenced by reductions in body weight (BW), liver weight (LW), and epididymal fat weight (EFW) compared to model rats and other polarity fractions of BR. Furthermore, LBR notably down-regulated serum and liver levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C), while up-regulating high-density lipoprotein cholesterol (HDL-C) in serum. Mechanistically, liver transcriptome analysis indicated that fatty acid metabolism may be a crucial pathway for the improvement of NAFLD following LBR treatment. Lipidomics data suggested that LBR can modulate the metabolic profile in NAFLD rats. Enrichment analysis revealed that glycerophospholipid and glycerolipid metabolism might be key pathways involved in the development of NAFLD. RT-qPCR analysis demonstrated that LBR could regulate the expression of lipid-related genes in these critical pathways. Additionally, Spearman correlation analysis showed a strong relationship between lipid metabolic biomarkers, pathological indices, and lipid-related genes. Moreover, protein-protein interaction (PPI) network and molecular docking analyses identified seven key targets with six ingredients of LBR exhibiting good binding capacity (< -5.0 kcal/mol). Finally, Western blotting analysis indicated that LBR up-regulates the expression levels of PPARα, CPT1, and FABP1 while down-regulating the expression levels of SREBF1 and SCD1, thereby improving metabolism and exerting a lipid-lowering effect. ConclusionIn conclusion, the present research elucidated the lipid-lowering mechanisms of the active fractions of BR. Both BR and LBR presented themselves as promising candidates for the development of novel pharmacological agents targeting NAFLD. LBR effectively ameliorated lipid disturbances associated with HFD-induced NAFLD by modulating the metabolism of fatty acids, cholesterol, glycerolipid, and glycerophospholipids. Consequently, LBR held significant potential for development as an effective lipid-lowering therapeutic.

The molecular regulated mechanism of METTL3 and FTO in lipid metabolism of Hu sheep

BackgroundBalanced lipid metabolism can improve the growth performance and meat quality of livestock. The m6A methylation-related genes METTL3 and FTO play important roles in animal lipid metabolism; however, the mechanism through which they regulate lipid metabolism in sheep is unclear. ResultsWe established lipid deposition models of hepatocytes and preadipocytes in Hu sheep. In the hepatocyte lipid deposition model, the genes expression levels of FABP4, Accα, ATGL and METTL3, METTL14, and FTO—were significantly up-regulated after lipid deposition (P < 0.05). Transcriptomic and metabolomic analyses showed that lipid deposition had a significant effect on MAPK, steroid biosynthesis, and glycerophospholipid metabolism pathway in hepatocytes. The m6A methylation level decreased but the difference was not significant after METTL3 interference, and the expression levels of FABP4 and ATGL increased significantly (P < 0.05); the m6A methylation level significantly increased following METTL3 overexpression, and LPL and ATGL expression levels significantly decreased (P < 0.05), indicating that overexpression of METTL3 inhibited the expression of lipid deposition-related genes in a m6A-dependent manner. The m6A methylation level was significantly increased, ATGL expression was significantly decreased (P < 0.05), and LPL, FABP4, and Accα expression was not significantly changed following FTO interference (P > 0.05); the m6A methylation level was significantly decreased after FTO overexpression, and LPL, FABP4, and ATGL expression was significantly increased (P < 0.05), indicating that FTO overexpression increased the expression of lipid deposition-related genes in a m6A-dependent manner. Transcriptomic and metabolomic analyses showed that m6A methylation modification mainly regulated lipid metabolism through triglyceride metabolism, adipocytokine signaling, MAPK signaling, and fat digestion and absorption in hepatocytes. In the lipid deposition model of preadipocytes, the regulation of gene expression is the same as that in hepatocytes. ConclusionsMETTL3 significantly inhibited the expression of lipid deposition-related genes, whereas FTO overexpression promoted lipid deposition. Our study provides a theoretical basis and reference for accurately regulating animal lipid deposition by mastering METTL3 and FTO genes to promote high-quality animal husbandry.

PPARγ and C/EBPα enable adipocyte differentiation upon inhibition of histone methyltransferase PRC2 in malignant tumors

Loss of terminal differentiation is a hallmark of cancer and offers a potential mechanism for differentiation therapy. Polycomb Repressive Complex 2 (PRC2) serves as the methyltransferase for K27 of histone H3 that is crucial in development. While PRC2 inhibitors show promise in treating various cancers, the underlying mechanisms remain incompletely understood. Here, we demonstrated that the inhibition or depletion of PRC2 enhanced adipocyte differentiation in malignant rhabdoid tumors (MRTs) and mesenchymal stem cells (MSCs), through upregulation of PPARG and CEBPA. Mechanistically, PRC2 directly represses their transcription through H3K27 methylation, as both genes exhibit a bivalent state in MSCs. Knockout of PPARG compromised C/EBPα expression and impeded the PRC2 inhibitor-induced differentiation into adipocytes. Furthermore, the combination of the PPARγ agonist rosiglitazone and the PRC2 inhibitor MAK683 exhibited a higher inhibition on Ki67 positivity in tumor xenograft compared to MAK683 alone. High CEBPA, PLIN1 and FABP4 levels positively correlated with favorable prognosis in sarcoma patients in TCGA cohort. Together, these findings unveil an epigenetic regulatory mechanism for PPARG and highlight the essential role of PPARγ and C/EBPα in the adipocyte differentiation of MRTs and sarcomas with a potential clinical implication.

Development of a humanized anti-FABP4 monoclonal antibody for potential treatment of breast cancer

BackgroundBreast cancer is the most common cancer in women diagnosed in the U.S. and worldwide. Obesity increases breast cancer risk without clear underlying molecular mechanisms. Our studies demonstrate that circulating adipose fatty acid binding protein (A-FABP, or FABP4) links obesity-induced dysregulated lipid metabolism and breast cancer risk, thus potentially offering a new target for breast cancer treatment.MethodsWe immunized FABP4 knockout mice with recombinant human FABP4 and screened hybridoma clones with specific binding to FABP4. The potential effects of antibodies on breast cancer cells in vitro were evaluated using migration, invasion, and limiting dilution assays. Tumor progression in vivo was evaluated in various types of tumorigenesis models including C57BL/6 mice, Balb/c mice, and SCID mice. The phenotype and function of immune cells in tumor microenvironment were characterized with multi-color flow cytometry. Tumor stemness was detected by ALDH assays. To characterize antigen-antibody binding capacity, we determined the dissociation constant of selected anti-FABP4 antibodies via surface plasmon resonance. Further analyses in tumor tissue were performed using 10X Genomics Visium spatial single cell technology.ResultsHerein, we report the generation of humanized monoclonal antibodies blocking FABP4 activity for breast cancer treatment in mouse models. One clone, named 12G2, which significantly reduced circulating levels of FABP4 and inhibited mammary tumor growth, was selected for further characterization. After confirming the therapeutic efficacy of the chimeric 12G2 monoclonal antibody consisting of mouse variable regions and human IgG1 constant regions, 16 humanized 12G2 monoclonal antibody variants were generated by grafting its complementary determining regions to selected human germline sequences. Humanized V9 monoclonal antibody showed consistent results in inhibiting mammary tumor growth and metastasis by affecting tumor cell mitochondrial metabolism.ConclusionsOur current evidence suggests that targeting FABP4 with humanized monoclonal antibodies may represent a novel strategy for the treatment of breast cancer and possibly other obesity- associated diseases.

Adipocyte fatty acid-binding protein (FABP4) as a potential biomarker for predicting metabolically driven low-grade and organ damage in thalassemia syndromes

Adipocyte fatty acid-binding protein (A-FABP; FABP4) plays a significant role in the pathogenesis and progression of metabolically driven low-grade inflammation and organ damage. This study aimed to evaluate the performance of circulating FABP4 as a predictive and diagnostic biomarker for thalassemia-associated cardiometabolic events. This case-control study enrolled 50 adults with β-thalassemia and 30 age-, sex-, and body mass index-matched controls. Participants underwent a comprehensive evaluation, including complete blood count, liver and kidney function tests, serum blood glucose, lipid profile, and ferritin levels, pelviabdominal ultrasound, ECG, and echocardiography after taking a full medical history and conducting a clinical examination. Serum levels of FABP4 were measured using an Enzyme-Linked-Immunosorbent-Assay. The diagnostic performance of FABP4 was assessed using receiver operator characteristic (ROC) curve analysis to determine optimal values for excluding and confirming cardiometabolic metflammation. The thalassemia cohort exhibited a statistically significant higher concentration of FABP4 compared to the control group (p-value < 0.001). Positive correlations were found between FABP4 and ferritin serum levels above 800 or 1000 ug/L, as well as with ALT, TGS, and LDL (p-value < 0.05). Circulating FABP4 was identified as a statistically significant risk factor for thalassemia-associated cardiometabolic comorbidities (OR = 84.00, 95%CI:18.6–378.6, p-value < 0.001). ROC analysis determined that the FABP4 exclusionary cut-off value > 2.30 ng/ml could effectively discriminate between thalassemia-associated adverse metaflammation and controls, while the FABP4 confirmatory cut-off value was > 2.58 ng/ml. In conclusion, circulating FABP4 appears to be a potential risk factor for predicting progression to cardiometabolic events in thalassemia-associated adverse metaflammation. FABP4 holds promise as a diagnostic and prognostic biomarker for disease monitoring and risk stratification. Further validation through large-scale, multicenter, prospective studies is warranted.

Fatty Acid-Binding Protein 4-Mediated Regulation Is Pivotally Involved in Retinal Pathophysiology: A Review.

Fatty acid-binding proteins (FABPs), a family of lipid chaperone molecules that are involved in intracellular lipid transportation to specific cellular compartments, stimulate lipid-associated responses such as biological signaling, membrane synthesis, transcriptional regulation, and lipid synthesis. Previous studies have shown that FABP4, a member of this family of proteins that are expressed in adipocytes and macrophages, plays pivotal roles in the pathogenesis of various cardiovascular and metabolic diseases, including diabetes mellitus (DM) and hypertension (HT). Since significant increases in the serum levels of FABP4 were detected in those patients, FABP4 has been identified as a crucial biomarker for these systemic diseases. In addition, in the field of ophthalmology, our group found that intraocular levels of FABP4 (ioFABP4) and free fatty acids (ioFFA) were substantially elevated in patients with retinal vascular diseases (RVDs) including proliferative diabetic retinopathy (PDR) and retinal vein occlusion (RVO), for which DM and HT are also recognized as significant risk factors. Recent studies have also revealed that ioFABP4 plays important roles in both retinal physiology and pathogenesis, and the results of these studies have suggested potential molecular targets for retinal diseases that might lead to future new therapeutic strategies.

Multi-omics differences in the bone marrow between essential thrombocythemia and prefibrotic primary myelofibrosis

Essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (pre-PMF) are Philadelphia chromosome-negative myeloproliferative neoplasms. These conditions share overlapping clinical presentations; however, their prognoses differ significantly. Current morphological diagnostic methods lack reliability in subtype differentiation, underlining the need for improved diagnostics. The aim of this study was to investigate the multi-omics alterations in bone marrow biopsies of patients with ET and pre-PMF to improve our understanding of the nuanced diagnostic characteristics of both diseases. We performed proteomic analysis with 4D direct data-independent acquisition and microbiome analysis with 2bRAD-M sequencing technology to identify differential protein and microbe levels between untreated patients with ET and pre-PMF. Laboratory and multi-omics differences were observed between ET and pre-PMF, encompassing diverse pathways, such as lipid metabolism and immune response. The pre-PMF group showed an increased neutrophil-to-lymphocyte ratio and decreased high-density lipoprotein and cholesterol levels. Protein analysis revealed significantly higher CXCR2, CXCR4, and MX1 levels in pre-PMF, while APOC3, APOA4, FABP4, C5, and CFB levels were elevated in ET, with diagnostic accuracy indicated by AUC values ranging from 0.786 to 0.881. Microbiome assessment identified increased levels of Mycobacterium, Xanthobacter, and L1I39 in pre-PMF, whereas Sphingomonas, Brevibacillus, and Pseudomonas_E were significantly decreased, with AUCs for these genera ranging from 0.833 to 0.929. Our study provides preliminary insights into the proteomic and microbiome variations in the bone marrow of patients with ET and pre-PMF, identifying specific proteins and bacterial genera that warrant further investigation as potential diagnostic indicators. These observations contribute to our evolving understanding of the multi-omics variations and possible mechanisms underlying ET and pre-PMF.

OGG1 prevents atherosclerosis-induced vascular endothelial cell injury through mediating DNA damage repair.

This study was designed to investigate the role of 8-oxoguanine DNA glycosylase 1 (OGG1) in preventing atherosclerosis-induced vascular EC injury, thereby providing a theoretical basis for the exploration of drug targets and treatment methods for atherosclerosis. Human umbilical vein cell line (EA.hy926) was treated with ox-LDL to construct an in vitro atherosclerotic cell model. pcDNA3.1-OGG1 was transfected into EA.hy926 cells to overexpress OGG1. qRT-PCR, CCK-8 assay, flow cytometry, oil red O staining, ELISA, comet assay and western blot were used to evaluate the OGG1 expression, viability, apoptosis level, lipid droplet content, 8-OHdG level and DNA damage of cells in each group. Compared with the Control group, ox-LDL stimulation of endothelial cells significantly decreased cell viability, promoted apoptosis and DNA damage, and increased intracellular levels of 8-OHdG and γH2AX, while decreasing protein levels of PPARγ, FASN, FABP4, RAD51 and POLB. However, overexpression of OGG1 can significantly inhibit ox-LDL damage to endothelial cells, promote lipid metabolism, decrease lipid droplet content, and improve DNA repair function. Over-expression of OGG1 improves DNA repair. Briefly, OGG1 over-expression enhances the DNA damage repair of ECs by regulating the expression levels of γH2AX, RAD51 and POLB, thereby enhancing cell viability and reducing apoptosis.

The obesogen bisphenol A promotes adipogenesis in canine adipose-derived stem cells: Potential implication in dog obesity

The growing number of companion dogs has contributed to a rapidly growing market for pet products, including dog toys. However, little is known about the hazardous substances released from dog toys. This study aims to examine the potential presence of obesogens, a subset of endocrine-disrupting chemicals (EDCs) that are widely utilized as raw materials in the manufacture of dog toy components, and their effects on dog health. To achieve this, we adapted and employed a migration method typically used for children's products to simulate obesogen exposure in dogs through sucking or chewing toys. We demonstrated that out of various obesogens, bisphenol A (BPA) was released from dog toys into synthetic saliva, whereas phthalates and azo dyes were not detected in any of the leachates. Additionally, we found that BPA induced adipogenic differentiation in canine adipose-derived stem cells (cADSCs). Our RNA sequencing experiments revealed that BPA alters the adipogenesis-related gene signature in cADSCs by elevating the expression levels of ADIPOQ, PLIN1, PCK1, CIDEC, and FABP4. The associated transcriptional changes are involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which may contribute to the promotion of adipogenesis by BPA. Our findings suggest that companion dogs are at risk of BPA exposure, which may contribute to obesity in dogs. Therefore, the implementation of precautionary measures is crucial.

#363 Altered filtration of middle-sized molecules is related to cardiovascular disease-related proteins

Abstract Background and Aims Cardiovascular (CV) complications, driven by complex vascular-metabolic interactions, are the leading cause of frailty in chronic kidney disease (CKD) complications. Advancing knowledge on cardio-renal interactions is a key to preventive and treatment strategies. Still, the cost-effective tools and biomarkers for early detection of altered glomerular filtration that subsequently leads to accelerated cardiovascular aging and, thus, higher CV mortality are lacking. Our objective was to investigate how molecules of varying masses, specifically cystatin C and creatinine, are filtered in kidney in relation to variations of plasma protein levels that might accelerate vascular changes, ultimately leading to early vascular aging and chronic kidney disease (CKD). Method From the Malmo Diet Cancer cohort, 4426 out of the 5061 participants had cardiovascular and renal biomarkers measured (mean age of 57 ± 6 years). These biomarkers included factors related to tissue growth and repair (EGFR), matrix metalloproteinases (MMP-12), proinflammatory cytokines (TNF-R1, TNF-R2, CXCL13, CXCL5), markers of vascular repair (SCF), homeostatic cytokines (CCL19), anti-apoptotic proteins (REG-4), adipokines (FABP4, LEP), as well as other cardiovascular proteins (NT-pro-BNP, MB) and indicators of kidney function. These 13 proteins were analyzed using multiplex proximity extension assay (Olink Cardiovascular II and Oncology panels), and have molecular masses either like creatinine (0.113 kDa) or cystatin C (13.3 kDa). These proteins were previously shown to be associated with measured glomerular filtration rate (mGFR) by Christensson A et al. (Proteomics Clin App, 2018). Kidney function was estimated by using cystatin C (CAPA, CKD-EPIcys) and creatinine (Lund-Malmo revised, CKD-EPIcr) equations. The filtration ratio was presented as CAPA/LMrev and CKD-EPIcys/CKD-EPIcr. The subgroups of this ratio were &amp;lt;0.70. Results Mean kidney function was as follows: 65 (±15)/ 69 (±16)/ 78 (±13) and 76 (±14) mL/min/1.73 m2 (CAPA/ CKD-EPIcys/ LMrev and CKD-EPIcr, respectively). The CAPA/LMrev filtration ratio was 0.84 (±0.18), whereas CKD-EPIcys/cr was 0.91 (±0.19). The filtration ratio negatively correlated with TNF-R1, TNF-R2, SCF, MMP-12, FABP4, LEP, NT-pro-BNP, CCL19, CXCL5, CXCL13 and REG-4; positively to EGFR and MB (all p &amp;lt; 0.001). In the whole cohort, participants with filtration ratio below 0.7 had significantly higher levels of TNF-R1, TNF-R2, MMP12, FABP4, LEP, NT-pro-BNP, CCL19, REG-4, and CXCL13, but similar levels of EGFR. CXCL5 and SCF levels were higher at &amp;lt;0.70 compared to 0.84-0.99 and &amp;gt;1.0 (Fig. 1). Interestingly, in women, MB was highest at &amp;lt;0.70; SCF level was higher at &amp;lt;0.70 compared to 0.84-0.99 and &amp;gt;1.00; EGFR level was highest at 0.70-0.84 compared to 0.84-0.99. In men, higher FABP4, LEP, CCL19, and MB were observed at &amp;lt;0.70 compared to 0.84-0.99 and &amp;gt;1.00. Conclusion Altered glomerular filtration for middle-sized molecules is related to the accumulation of plasma proteins that have similar molecular mass to creatinine and cystatin C and have sex-specific patterns. The proteins studied have been previously shown to contribute to vascular aging, cardiac damage and remodeling, and chronic kidney disease, and thus enlighten complex mechanisms behind cardio-renal interactions.

Investigating the Role of FABP4 in Diabetes and Obesity and the Influence of Age and Ethnicity: A Comprehensive Analysis of a Cohort from the KEDP-Study.

Adipocyte P2 (aP2), also known as FABP4, is an adipokine that adipose tissue produces and expresses in macrophages. Its primary role is to facilitate the transportation of fatty acids across cell membranes. Numerous studies have reported associations between FABP4 and the development of metabolic disorders. However, there is limited knowledge regarding FABP4 expression in diabetes and obesity, especially about different age groups, genders, and ethnicities. This study aims to investigate the association between FABP4 levels, diabetes mellitus, and obesity within various ethnic groups. We measured plasma FABP4 concentrations in a cohort of 2083 patients from the KDEP study and gathered anthropometric data. Additionally, we collected and analyzed clinical, biochemical, and glycemic markers using multivariate regression analysis. The average FABP4 concentration was significantly higher in female participants than in males (18.8 ng/mL vs. 14.4 ng/mL, p < 0.001, respectively), and in those over 50 years old compared to those under 50 years of age (19.3 ng/mL vs. 16.2 ng/mL, p < 0.001, respectively). In this study, significant positive associations were found between the plasma level of FABP4 and obesity markers: BMI (r = 0.496, p < 0.001), hip circumference (r = 0.463, p < 0.001), and waist circumference (WC) (r = 0.436, p < 0.001). Similar observations were also seen with glycemic markers, which included HbA1c (r = 0.126, p < 0.001), fasting blood glucose (FBG) (r = 0.184, p < 0.001), fasting insulin (r = 0.326, p < 0.001), and HOMA-IR (r = 0.333, p < 0.001). Importantly, these associations remained significant even after adjusting for age, gender, and ethnicity. Furthermore, FABP4 levels were negatively associated with male gender (β: -3.85, 95% CI: -4.92, -2.77, p < 0.001), and positively associated with age (β: 0.14, 95% CI: 0.096, 0.183, p < 0.001), BMI (β: 0.74, 95% CI: 0.644, 0.836, p < 0.001), and fasting insulin (β: 0.115, 95% CI: 0.091, 0.138, p < 0.001). In this study, plasma FABP4 levels were significantly higher in diabetic and obese participants, and they were strongly influenced by age, gender, and ethnicity. These findings suggest that FABP4 may serve as a valuable prognostic and diagnostic marker for obesity and diabetes, particularly among female patients, individuals over 50 years old, and specific ethnic groups.

Sodium-glucose cotransporter 1 promotes the biofunctions of perivascular preadipocytes mediated by Akt/mTOR/p70S6K signaling pathway.

The influence of SGLT-1 on perivascular preadipocytes (PVPACs) and vascular remodeling is not well understood. This study aimed to elucidate the role and mechanism of SGLT-1-mediated PVPACs bioactivity. PVPACs were cultured in vitro and applied ex vivo to the carotid arteries of mice using a lentivirus-based thermosensitive in situ gel (TISG). The groups were treated with Lv-SGLT1 (lentiviral vector, overexpression), Lv-siSGLT1 (RNA interference, knockdown), or specific signaling pathway inhibitors. Assays were conducted to assess changes in cell proliferation, apoptosis, glucose uptake, adipogenic differentiation, and vascular remodeling in the PVPACs. Protein expression was analyzed by Western blotting, immunocytochemistry, and/or immunohistochemistry. The methyl thiazolyl tetrazolium (MTT) assay and Hoechst 33342 staining indicated that SGLT-1 overexpression significantly promoted PVPACs proliferation and inhibited apoptosis in vitro. Conversely, SGLT-1 knockdown exerted the opposite effect. Oil Red O staining revealed that SGLT-1 overexpression facilitated adipogenic differentiation, while its inhibition mitigated these effects. 3H-labeled glucose uptake experiments demonstrated that SGLT-1 overexpression enhanced glucose uptake by PVPACs, whereas RNA interference-mediated SGLT-1 inhibition had no significant effect on glucose uptake. Moreover, RT-qPCR, Western blotting, and immunofluorescence analyses revealed that SGLT-1 overexpression upregulated FABP4 and VEGF-A levels and activated the Akt/mTOR/p70S6K signaling pathway, whereas SGLT-1 knockdown produced the opposite effects. In vivo studies corroborated these findings and indicated that SGLT-1 overexpression facilitated carotid artery remodeling. Our study demonstrates that SGLT-1 activation of the Akt/mTOR/p70S6K signaling pathway promotes PVPACs proliferation, adipogenesis, glucose uptake, glucolipid metabolism, and vascular remodeling.NEW & NOTEWORTHY SGLT-1 is expressed in PVPACs and can affect preadipocyte glucolipid metabolism and vascular remodeling. SGLT-1 promotes the biofunctions of PVPACs mediated by Akt/mTOR/p70S6K signaling pathway. Compared with caudal vein or intraperitoneal injection, the external application of lentivirus-based thermal gel around the carotid artery is an innovative attempt at vascular remodeling model, it may effectively avoid the transfection of lentiviral vector into the whole body of mice and the adverse effect on experimental results.

HOXA9 gene inhibits proliferation and differentiation and promotes apoptosis of bovine preadipocytes

BackgroundHox gene family is an important transcription factor that regulates cell process, and plays a role in the process of adipocytes differentiation and fat deposition. Previous transcriptome sequencing studies have indicated that the Homeobox A9 gene (HOXA9) is a candidate gene for regulating the process of bovine lipid metabolism, but the function and specific mechanism of action remain unclear. Therefore, this study aims to explore the role of HOXA9 in the proliferation, differentiation and apoptosis of bovine preadipocytes through gain-of-function and lose-of-function.ResultIt found HOXA9 highly expressed in bovine adipose tissue, and its expression level changed significantly during adipocytes differentiation process. It gave a hint that HOXA9 may be involved in the process of bovine lipid metabolism. The results of HOXA9 gain-of-function experiments indicated that HOXA9 appeared to act as a negative regulator not only in the differentiation but also in the proliferation of bovine preadipocytes, which is mainly reflected that overexpression of HOXA9 down-regulate the mRNA and protein expression level of PPARγ, CEBPα and FABP4 (P < 0.05). The mRNA expression level of CDK1, CDK2, PCNA, CCNA2, CCNB1, CCND1 and CCNE2, as well as the protein expression of CDK2 also significantly decreased. The decrease of lipid droplets content was the main characteristic of the phenotype (P < 0.01), which further supported the evidence that HOXA9 was a negative regulator of preadipocytes differentiation. The decrease of cell proliferation rate and EdU positive rate, as well as the limitation of transition of preadipocytes from G0/G1 phase to S phase also provided evidence for the inhibition of proliferation. Apart from this above, we noted an interesting phenomenon that overexpression of HOXA9 showed in a significant upregulation of both mRNA and protein level of apoptosis markers, accompanied by a significant increase in cell apoptosis rate. These data led us not to refute the fact that HOXA9 played an active regulatory role in apoptosis. HOXA9 loss-of-function experiments, however, yielded the opposite results. Considering that HOXA9 acts as a transcription factor, we predicted its target genes. Dual luciferase reporter assay system indicated that overexpression of HOXA9 inhibits activity of PCNA promoter.ConclusionTaken together, we demonstrated for the first time that HOXA9 played a role as a negative regulatory factor in the differentiation and proliferation of preadipocytes, but played a positive regulatory role in apoptosis, and it may play a regulatory role by targeting PCNA. This study provides basic data for further exploring the regulatory network of intramuscular fat deposition in bovine.

A New Insight into Fatty Acid Binding Protein 4 Mechanisms and Therapeutic Implications in Obesity-Associated Diseases: A Mini Review.

Fatty acid binding proteins (FABPs), such as FABP4 (aP2, A-FABP), are essential for cellular lipid regulation, membrane-protein interactions, and the modulation of metabolic and inflammatory pathways. FABP4, primarily expressed in adipocytes, monocytes, and macrophages, is integrated into signaling networks that influence immune responses and insulin activity. It has been linked to obesity, inflammation, lipid metabolism, insulin resistance, diabetes, cardiovascular disease, and cancer. Inhibition of FABP4 is emerging as a promising strategy for treating obesity-related conditions, particularly insulin resistance and diabetes. Elevated FABP4 levels in individuals with a BMI above 30 underscore its association with obesity. Furthermore, FABP4 levels are higher not only in the tissues but also in the blood, promoting the onset and development of various cancers. Understanding its broader role reveals involvement in the mechanisms underlying metabolic syndrome, contributing to various metabolic and inflammatory responses. While blocking FABP4 offers an alternative therapeutic approach, a comprehensive understanding of potential side effects is crucial before clinical use. This review aims to provide concise insights into FABP4, elucidating its mechanisms and potential therapeutic applications in obesity and associated disorders, contributing to innovative interventions against metabolic syndrome and obesity.

Abstract 5910: Developing a novel humanized anti-FABP4 antibody for breast cancer treatment

Abstract Circulating levels of adipocyte fatty acid binding protein (A-FABP, also known as FABP4) are linked with metabolic dysregulation. Our previous study demonstrated that high serum levels of FABP4 increased the risk of breast cancer, indicating that circulating FABP4 could be a potential therapeutic target for this disease. In this study, we generated mouse monoclonal antibodies (mAb) against FABP4 by immunizing C57BL/6 mice with recombinant human FABP4. After screening over 1300 hybridoma clones, we identified an FABP4 neutralizing mAb, named 12G2, which inhibited breast cancer growth in various mouse models. To facilitate clinical application, we engineered chimeric and humanized variants of the 12G2 mAb. Notably, the humanized variant, 12G2-variant 9 (12G2-vt9), effectively inhibited mammary tumor growth and progression by reducing the activity of FABP4/ALDH1 in different breast cancer mouse models. Our findings suggest that 12G2-Vt9 is a promising neutralizing mAb targeting FABP4-mediated cancer stemness through ALDH1 signaling, offering potential as a targeted therapeutic antibody for the clinical treatment of breast cancer. Citation Format: Jiaqing Hao, Matthew Yorek, Jian yu, Anthony Avellino, Bing Li. Developing a novel humanized anti-FABP4 antibody for breast cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5910.

Abstract 443: Unsaturated fatty acids promote cell cycle progression and proliferation of platinum resistant ovarian cancer cells

Abstract Introduction: Ovarian cancer (OC) depends on fat as fuel for metastasis and growth. We have previously demonstrated that cisplatin resistant (Pt-R) OC cells uptake higher amounts of fatty acids (FAs) compared to sensitive (Pt-S) cells- a process which facilitates cancer cell survival under cisplatin-induced oxidative stress. Here we aimed to determine which class of FAs promotes the Pt-R phenotype and to identify the mechanism through which FAs support cancer survival. Materials and methods: We used two isogenic OC cell lines pairs, sensitive and resistant to cisplatin: OVCAR5 Pt-S (IC50 = 2.881μM) vs Pt-R (IC50 = 6.831 μM) and PEO1 (IC50 = 4.901 μM) vs PEO4 (IC50 = 8.285 μM). Cells were cultured under low serum conditions, supplemented with 50 µM oleic (OA) or 50 µM palmitic acid (PA), and used for viability assays, RNA-Seq, and cell cycle analysis. Quantitative RT-PCR measured expression of key FAs transporters in Pt-S and Pt-R cells. Results: A viability assay showed that Pt-R cells were less viable under serum depletion compared to Pt-S OC cells. OA (unsaturated), but not PA (saturated), promoted proliferation of both OC cell lines, and rescued Pt-R vs Pt-S cells; 268.4% vs 91.6% for OVCAR-5 and 38.1% for PEO4 vs 12.1% for PEO1, suggesting that Pt-R cells depend more on unsaturated FAs compared to Pt-S cells. Quantification of key FAs transporters demonstrated that Pt-R cell expressed higher levels of FABP4, FABP5 and CD36 compared to Pt-S cells. Treatment with an FABP inhibitor reduced the Pt IC50 in Pt-R cells (from 11.893 μM to 5.0415 μM in OVCAR5 and from 8.285 μM to 6.968 μM in PEO4). RNA-Seq analysis analysed transcriptomic changes induced by 24 hour treatment with OA in OVCAR5 cells. There were 923 differentially expressed protein-coding genes, with 300 upregulated and 623 downregulated transcripts (FDR&amp;lt;0.05). Pathway analysis revealed cell cycle related pathways like: cell cycle mitotic, cell cycle checkpoints, G2/M checkpoints among the top 10 most significantly upregulated pathways and E2F1 was identified as the main effector. Cell cycle analysis confirmed that OA induced increased percentages of cells in S- and G2/M phases - from 6.95% to 11.6% (p&amp;lt;0.05), and 13.6 to 17.6% (P&amp;lt;0.05), respectively. Treatment with an E2F1 inhibitor significantly reduced the OA-induced cell proliferation. Conclusion: Pt-R OC cells are dependent on unsaturated FAs compared to Pt-S cells and upregulate key transporters to allow increased uptake of FAs. OA supports proliferation of Pt-R cells and cell cycle progression from G1 to S- and G2/M phases. Ongoing experiments focus on key mechanisms activated by unsaturated FAs in Pt-R cells. Citation Format: Ana Maria Isac, Guangyuan Zhao, Horacio Cardenas, Daniela Matei. Unsaturated fatty acids promote cell cycle progression and proliferation of platinum resistant ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 443.