Inhibition of ANGPTL8 protects against diabetes-associated cognitive dysfunction by reducing synaptic loss via the PirB signaling pathway.

BACKGROUND: Type 2 diabetes mellitus (T2D) is associated with an increased risk of cognitive dysfunction. Angiopoietin-like protein 8 (ANGPTL8) is an important regulator in T2D, but the role of ANGPTL8 in diabetes-associated cognitive dysfunction remains unknown. Here, we explored the role of ANGPTL8 in diabetes-associated cognitive dysfunction through its interaction with paired immunoglobulin-like receptor B (PirB) in the central nervous system. METHODS: The levels of ANGPTL8 in type 2 diabetic patients with cognitive dysfunction and control individuals were measured. Mouse models of diabetes-associated cognitive dysfunction were constructed to investigate the role of ANGPTL8 in cognitive function. The cognitive function of the mice was assessed by the Barnes Maze test and the novel object recognition test, and levels of ANGPTL8, synaptic and axonal markers, and pro-inflammatory cytokines were measured. Primary neurons and microglia were treated with recombinant ANGPTL8 protein (rA8), and subsequent changes were examined. In addition, the changes induced by ANGPTL8 were validated after blocking PirB and its downstream pathways. Finally, mice with central nervous system-specific knockout of Angptl8 and PirB-/- mice were generated, and relevant in vivo experiments were performed. RESULTS: Here, we demonstrated that in the diabetic brain, ANGPTL8 was secreted by neurons into the hippocampus, resulting in neuroinflammation and impairment of synaptic plasticity. Moreover, neuron-specific Angptl8 knockout prevented diabetes-associated cognitive dysfunction and neuroinflammation. Mechanistically, ANGPTL8 acted in parallel to neurons and microglia via its receptor PirB, manifesting as downregulation of synaptic and axonal markers in neurons and upregulation of proinflammatory cytokine expression in microglia. In vivo, PirB-/- mice exhibited resistance to ANGPTL8-induced neuroinflammation and synaptic damage. CONCLUSION: Taken together, our findings reveal the role of ANGPTL8 in the pathogenesis of diabetes-associated cognitive dysfunction and identify the ANGPTL8-PirB signaling pathway as a potential target for the management of this condition.

Periodontitis promotes hepatocellular carcinoma in Stelic Animal model (STAM) mice.

Periodontitis is a prevalent oral inflammatory disease that leads to alveolar bone loss and may exert an adverse impact on systemic health. Periodontal disease may be associated with hepatocellular carcinoma (HCC); however, the mechanism of such an association is unknown. In this study, Stelic Animal model (STAM) mice, a model of nonalcoholic steatohepatitis (NASH)-HCC, were induced to develop periodontitis and subjected to histopathological and immunological analyses. HCC progression was greater in STAM mice with experimental periodontitis compared with that in STAM mice without experimental periodontitis. Tumor necrosis factor-α (TNFα), matrix metalloproteinase-9 (MMP9), collagen 1, and angiopoietin-like protein 2 (ANGPTL2) gene expression was significantly increased in the liver of the periodontitis group. ANGPTL2 was previously reported to be involved in the pathogenesis of periodontitis, and HCC and ANGPTL2 protein tended to be more abundant in the pocket epithelium of STAM mice with experimental periodontitis than in control STAM mice. ANGPTL2 levels in the serum of STAM mice with experimental periodontitis tended to be higher than in control STAM mice. Our results indicate that ANGPTL2 is produced in chronically inflamed periodontal tissue and then travels to the liver via the bloodstream where it accumulates to promote the progression of hepatocellular carcinoma.

Remodeling of tumor microenvironment by extracellular matrix protein 1a differentially regulates ovarian cancer metastasis.

We previously reported that extracellular matrix protein 1 isoform a (ECM1a) promotes epithelial ovarian cancer (EOC) through autocrine signaling by binding to cell surface receptors αXß2. However, the role of ECM1a as a secretory molecule in the tumor microenvironment is rarely reported. In this study, we constructed murine Ecm1-knockout mice and human ECM1a-knockin mice and further generated orthotopic or peritoneal xenograft tumor models to mimic the different metastatic stages of EOC. We show that ECM1a induces oncogenic metastasis of orthotopic xenograft tumors, but inhibits early-metastasis of peritoneal xenograft tumors. ECM1a remodels extracellular matrices (ECM) and promotes remote metastases by recruiting and transforming bone marrow mesenchymal stem cells (BMSCs) into platelet-derived growth factor receptor beta (PDGFRß+) cancer-associated fibroblasts (CAFs) and facilitating the secretion of angiopoietin-like protein 2 (ANGPTL2). Competing with ECM1a, ANGPTL2 also binds to integrin αX through the P1/P2 peptides, resulting in negative effects on BMSC differentiation. Collectively, this study reveals the dual functions of ECM1a in remodeling of TME during tumor progression, emphasizing the complexity of EOC phenotypic heterogeneity and metastasis.

Angiopoietin-like growth factor-derived peptides as biological activators of adipose-derived mesenchymal stromal cells.

Adipose-derived mesenchymal stromal cells (AD-MSCs) are an essential issue in modern medicine. Extensive preclinical and clinical studies have shown that mesenchymal stromal/stem cells, including AD-MSCs, have specific properties (ability to differentiate into other cells, recruitment to the site of injury) of particular importance in the regenerative process. Ongoing research aims to elucidate factors supporting AD-MSC culture and differentiation in vitro. Angiopoietin-like proteins (ANGPTLs), known for their pleiotropic effects in lipid and glucose metabolism, may play a significant role in this context. Regeneration is a complex and dynamic process controlled by many factors. ANGPTL6 (Angiopoietin-related growth factor, AGF), among many activities modulated the biological activity of stem cells. This study examined the influence of synthesized AGF-derived peptides, designated as AGF9 and AGF27, on AD-MSCs. AGF9 and AGF27 enhanced the viability and migration of AD-MSCs and acted as a chemotactic factor for these cells. AGF9 stimulated chondrogenesis and lipid synthesis during AD-MSCs differentiation, influenced AD-MSCs cytokine secretion and modulated transcriptome for such basic cell activities as migration, transport of molecules, and apoptosis. The ability of AGF9 to modulate the biological activity of AD-MSCs warrants the consideration of this peptide a noteworthy therapeutic agent that deserves further investigation for applications in regenerative medicine.

Olink Profiling of Aqueous Humor Identifies Novel Biomarkers for Wet Age-Related Macular Degeneration.

Metabolic dysfunction is recognized as a contributing factor in the pathogenesis of wet age-related macular degeneration (wAMD). However, the specific metabolism-related proteins implicated in wAMD remain elusive. In this study, we assessed the expression profiles of 92 metabolism-related proteins in aqueous humor (AH) samples obtained from 44 wAMD patients and 44 cataract control patients. Our findings revealed significant alterations in the expression of 60 metabolism-related proteins between the two groups. Notably, ANGPTL7 and METRNL displayed promising diagnostic potential for wAMD, as evidenced by area under the curve values of 0.88 and 0.85, respectively. Subsequent validation studies confirmed the upregulation of ANGPTL7 and METRNL in the AH of wAMD patients and in choroidal neovascularization (CNV) models. Functional assays revealed that increased ANGPTL7 and METRNL played a pro-angiogenic role in endothelial biology by promoting endothelial cell proliferation, migration, tube formation, and spouting in vitro. Moreover, in vivo studies revealed the pro-angiogenic effects of ANGPTL7 and METRNL in CNV formation. In conclusion, our findings highlight the association between elevated ANGPTL7 and METRNL levels and wAMD, suggesting their potential as novel predictive and diagnostic biomarkers for this condition. These results underscore the significance of ANGPTL7 and METRNL in the context of wAMD pathogenesis and offer new avenues for future research and therapeutic interventions.

Carboxyl-terminal sequences in APOA5 are important for suppressing ANGPTL3/8 activity.

Apolipoprotein AV (APOA5) lowers plasma triglyceride (TG) levels by binding to the angiopoietin-like protein 3/8 complex (ANGPTL3/8) and suppressing its capacity to inhibit lipoprotein lipase (LPL) catalytic activity and its ability to detach LPL from binding sites within capillaries. However, the sequences in APOA5 that are required for suppressing ANGPTL3/8 activity have never been defined. A clue to the identity of those sequences was the presence of severe hypertriglyceridemia in two patients harboring an APOA5 mutation that truncates APOA5 by 35 residues ("APOA5Δ35"). We found that wild-type (WT) human APOA5, but not APOA5Δ35, suppressed ANGPTL3/8's ability to inhibit LPL catalytic activity. To pursue that finding, we prepared a mutant mouse APOA5 protein lacking 40 C-terminal amino acids ("APOA5Δ40"). Mouse WT-APOA5, but not APOA5Δ40, suppressed ANGPTL3/8's capacity to inhibit LPL catalytic activity and sharply reduced plasma TG levels in mice. WT-APOA5, but not APOA5Δ40, increased intracapillary LPL levels and reduced plasma TG levels in Apoa5-/- mice (where TG levels are high and intravascular LPL levels are low). Also, WT-APOA5, but not APOA5Δ40, blocked the ability of ANGPTL3/8 to detach LPL from cultured cells. Finally, an antibody against a synthetic peptide corresponding to the last 26 amino acids of mouse APOA5 reduced intracapillary LPL levels and increased plasma TG levels in WT mice. We conclude that C-terminal sequences in APOA5 are crucial for suppressing ANGPTL3/8 activity in vitro and for regulating intracapillary LPL levels and plasma TG levels in vivo.

Correlation between the serum FABP4, ANGPTL3, and ANGPTL4 levels and coronary artery disease.

BACKGROUND: Lipid metabolism related factors, such as angiopoietin-like protein 3 (ANGPTL3), angiopoietin-like 4 (ANGPTL4), fatty acid-binding protein 4 (FABP4) are newly discovered factors that can affect coronary artery disease (CAD). In this study, we aimed to investigate the relationship between CAD and these lipid metabolism factors. HYPOTHESIS: ANGPTL3, ANGPTL4, and FABP4 may provide a new method for the control of CAD risk factors and the prevention and treatment of CAD. METHODS: We enrolled 284 consecutive inpatients with suspected CAD and divided them into CAD and non-CAD groups based on the coronary angiography results. Serum ANGPTL3, ANGPTL4, FABP4, and tumor necrosis factor-α (TNF-α) levels were estimated using the enzyme-linked immunosorbent assay. Multivariate logistic regression was used to assess the risk factors for CAD. The receiver operating characteristic curve was used to determine the cutoff and diagnostic values. RESULTS: The serum TNF-α, FABP4, ANGPTL3, and ANGPTL4 values showed a significant difference between the CAD and non-CAD groups (p < .05). After adjusting for confounding factors, the FABP4, ANGPTL3, and ANGPTL4 levels were independently associated with CAD (p < .05). The ANGPTL3 expression level was an independent risk factor for CAD in patients with hypertension, but not in those without hypertension. The ANGPTL3 > 67.53 ng/mL, ANGPTL4 > 29.95 ng/mL, and FABP4 > 1421.25 ng/L combination had the highest diagnostic value for CAD. CONCLUSION: ANGPTL3, ANGPTL4, and FABP4 were identified as independent risk factors for CAD and have valuable clinical implications for the diagnosis and treatment of CAD.

A unified model for regulating lipoprotein lipase activity.

The regulation of triglyceride (TG) tissue distribution, storage, and utilization, a fundamental process of energy homeostasis, critically depends on lipoprotein lipase (LPL). We review the intricate mechanisms by which LPL activity is regulated by angiopoietin-like proteins (ANGPTL3, 4, 8), apolipoproteins (APOA5, APOC3, APOC2), and the cAMP-responsive element-binding protein H (CREBH). ANGPTL8 functions as a molecular switch, through complex formation, activating ANGPTL3 while deactivating ANGPTL4 in their LPL inhibition. The ANGPTL3-4-8 model integrates the roles of the aforementioned proteins in TG partitioning between white adipose tissue (WAT) and oxidative tissues (heart and skeletal muscles) during the feed/fast cycle. This model offers a unified perspective on LPL regulation, providing insights into TG metabolism, metabolic diseases, and therapeutics.

Tumor stroma-derived ANGPTL2 potentiates immune checkpoint inhibitor efficacy.

Use of immune checkpoint inhibitors (ICIs) as cancer immunotherapy has advanced rapidly in the clinic. We recently reported that tumor stroma-derived angiopoietin-like protein 2 (ANGPTL2) has tumor suppressive activity by enhancing dendritic cell-mediated CD8+ T cell anti-tumor immune responses. However, a direct impact of ANGPTL2 on ICI anti-tumor effect remains unclear. Here, we use a murine syngeneic model to show that host ANGPTL2 facilitates CD8+ T cell cross-priming and contributes to anti-tumor responses to ICIs in this context. Importantly, our analysis of public datasets indicated that ANGPTL2 expression is associated with positive responses to ICI therapy by human melanoma patients. We conclude that ANGPTL2-mediated stromal cell crosstalk facilitates anti-tumor immunity and ICI responsiveness. These findings overall provide novel insight into ANGPTL2 anti-tumor function and regulation of ICI-induced anti-tumor immunity.

ANGPTL3 Downregulation Increases Intracellular Lipids by Reducing Energy Utilization.

BACKGROUND: ANGPTL3 (angiopoietin-like protein 3) is a circulating protein with a key role in maintaining lipoprotein homeostasis. A monoclonal antibody against ANGPTL3 is an approved and well-tolerated treatment to reduce lipoproteins in familial hypercholesterolemia homozygotes. However, the reduction of hepatic ANGPTL3 synthesis using an antisense oligonucleotide unexpectedly resulted in a dose-dependent increase in liver lipid content and circulating transaminases, resulting in the termination of the clinical trial. Meanwhile, the use of silencing RNAs remains an area of active investigation. Our study sought to investigate whether intracellular downregulation of ANGPTL3 may lead to a primary increase in neutral lipids within the hepatocyte. METHODS: We downregulated ANGPTL3 by silencing RNA in primary human hepatocytes 3-dimensional spheroids, HepG2/LX-2 3-dimensional spheroids, and in HepG2, Hep3B2, and Huh7 cultured in 2 dimensions. RESULTS: ANGPTL3 downregulation increased neutral lipids in all models investigated. Interestingly, ANGPTL3 induced lower intracellular deiodinase type 1 protein levels resulting in a reduction in beta-oxidation and causing an increase in triglycerides stored in lipid droplets. CONCLUSIONS: In conclusion, intracellular ANGPTL3 downregulation by silencing RNA led to an increase in triglycerides content due to a reduction in energy substrate utilization resembling a primary intracellular hepatocyte hypothyroidism.

ANGPTL3 and ApoC-III inhibitors for treating hypertriglyceridemia in context: horses for courses?

PURPOSE OF REVIEW: Hypertriglyceridemia (HTG) is an independent and casual risk factor for atherosclerotic cardiovascular disease (ASCVD). There is an unmet need for more effective treatments for patients with HTG. Angiopoietin-like protein 3 (ANGPTL3) and apolipoprotein C-III (apoC-III) are key regulators of triglyceride-rich lipoprotein (TRL) metabolism. We review recent clinical trials targeting ANGPTL3 and apoC-III with monoclonal antibody and nucleic acid therapies, including antisense oligonucleotides and small interfering RNA. RECENT FINDINGS: ANGPTL3 and apoC-III inhibitors are effective in lowering plasma triglycerides and TRLs, with possibly greater efficacy with the inhibition of apoC-III. By contrast to ANGPTL3 inhibition that has the advantage of greater lowering of plasma low-density lipoprotein (LDL)-cholesterol and apoB levels, apoC-III inhibition only has a modest or no effect in lowering plasma LDL-cholesterol and apoB concentrations. Therapeutic inhibition of ANGPTL3 and apoC-III can correct HTG possibly by reducing production and increasing catabolism of TRL particles, but this remains to be formally investigated in patients with HTG. SUMMARY: Novel agents targeting ANGPTL3 and apoC-III can correct HTG and potentially lower risk of ASCVD in patients with HTG. The long-term safety and cost-effectiveness of these agents await confirmation in ongoing and future studies.

A novel fully human anti-NT-ANGPTL3 antibody from phage display library exhibits potent ApoB, TG, and LDL-C lowering activities in hyperlipidemia mice.

Dyslipidemia is characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and TG-rich lipoprotein (TGRLs) in circulation, and is closely associated with the incidence and development of cardiovascular disease. Angiopoietin-like protein 3 (ANGPTL3) deficiency has been identified as a cause of familial combined hypolipidemia in humans, which allows it to be an important therapeutic target for reducing plasma lipids. Here, we report the discovery and characterization of a novel fully human antibody F1519-D95aA against N-terminal ANGPTL3 (NT-ANGPTL3), which potently inhibits NT-ANGPTL3 with a KD as low as 9.21 nM. In hyperlipidemic mice, F1519-D95aA shows higher apolipoprotein B (ApoB) and TG-lowering, and similar LDL-C reducing activity as compared to positive control Evinacumab (56.50% vs 26.01% decrease in serum ApoB levels, 30.84% vs 25.28% decrease in serum TG levels, 23.32% vs 22.52% decrease in serum LDLC levels, relative to vehicle group). Molecular docking and binding energy calculations reveal that the F1519-D95aA-ANGPTL3 complex (10 hydrogen bonds, -65.51 kcal/mol) is more stable than the Evinacumab-ANGPTL3 complex (4 hydrogen bonds, -63.76 kcal/mol). Importantly, F1519-D95aA binds to ANGPTL3 with different residues in ANGPTL3 from Evinacumab, suggesting that F1519-D95aA may be useful for the treatment of patients resistant to Evinacumab. In conclusion, F1519-D95aA is a novel fully human anti-NT-ANGPTL3 antibody with potent plasma ApoB, TG, and LDL-C lowering activities, which can potentially serve as a therapeutic agent for hyperlipidemia and relevant cardiovascular diseases.

ANGPTL3 deficiency impairs lipoprotein production and produces adaptive changes in hepatic lipid metabolism.

Angiopoietin-like protein 3 (ANGPTL3) is a hepatically secreted protein and therapeutic target for reducing plasma triglyceride-rich lipoproteins and low-density lipoprotein (LDL) cholesterol. Although ANGPTL3 modulates the metabolism of circulating lipoproteins, its role in triglyceride-rich lipoprotein assembly and secretion remains unknown. CRISPR-associated protein 9 (CRISPR/Cas9) was used to target ANGPTL3 in HepG2 cells (ANGPTL3-/-) whereupon we observed ∼50% reduction of apolipoprotein B100 (ApoB100) secretion, accompanied by an increase in ApoB100 early presecretory degradation via a predominantly lysosomal mechanism. Despite defective particle secretion in ANGPTL3-/- cells, targeted lipidomic analysis did not reveal neutral lipid accumulation in ANGPTL3-/- cells; rather ANGPTL3-/- cells demonstrated decreased secretion of newly synthesized triglycerides and increased fatty acid oxidation. Furthermore, RNA sequencing demonstrated significantly altered expression of key lipid metabolism genes, including targets of peroxisome proliferator-activated receptor α, consistent with decreased lipid anabolism and increased lipid catabolism. In contrast, CRISPR/Cas9 LDL receptor (LDLR) deletion in ANGPTL3-/- cells did not result in a secretion defect at baseline, but proteasomal inhibition strongly induced compensatory late presecretory degradation of ApoB100 and impaired its secretion. Additionally, these ANGPTL3-/-;LDLR-/- cells rescued the deficient LDL clearance of LDLR-/- cells. In summary, ANGPTL3 deficiency in the presence of functional LDLR leads to the production of fewer lipoprotein particles due to early presecretory defects in particle assembly that are associated with adaptive changes in intrahepatic lipid metabolism. In contrast, when LDLR is absent, ANGPTL3 deficiency is associated with late presecretory regulation of ApoB100 degradation without impaired secretion. Our findings therefore suggest an unanticipated intrahepatic role for ANGPTL3, whose function varies with LDLR status.

Positive correlation of ANGPTL8 expression in human visceral adipose tissue with body mass index.

BACKGROUND: Angiopoietin-like protein 8 (ANGPTL8) is an important regulator of lipid metabolism. We aimed to investigate the difference of ANGPTL8 expression in different depots of adipose tissues between individuals with and without obesity, and its correlation with various metabolic parameters. METHODS: Subcutaneous (SAT) and visceral adipose tissue (VAT) samples were collected from patients who underwent bariatric or intra-abdominal surgery. Expression levels of ANGPTL8, monoglyceride lipase (MGL), monocyte chemoattractant protein-1 (MCP-1), leptin and adiponectin (APM1) were determined using real-time quantitative polymerase chain reaction. The correlation of ANGPTL8 expression with various metabolic parameters and other gene expression levels was analyzed using Person's correlation analysis. Logistic regression was used to establish a prediction model of obesity. RESULTS: Totally 330 subjects (obese: 281, non-obese: 49) were recruited. ANGPTL8 expression in VAT was significantly higher in the obesity group than in the non-obesity group (P = 0.0096). ANGPTL8 expression in VAT was positively correlated with body mass index (BMI) (r = 0.1169, P < 0.05) and was independently associated with obesity (O.R., 1.246; 95 % C.I. 1.013-21.533, P = 0.038). We also found the gene expression of ANGPTL8 in SAT and VAT was negatively correlated with APM1 expression in respective SAT and VAT. CONCLUSION: ANGPTL8 expression levels in VAT were higher in subjects with obesity, and positively correlated with BMI. This suggests a role of ANGPTL8 in the pathophysiology of obesity and may pave the way for novel treatment target of obesity.

Angiopoietin-like protein 8: a multifaceted protein instrumental in regulating triglyceride metabolism.

PURPOSE OF REVIEW: The angiopoietin-like (ANGPTL) proteins ANGPTL3 and ANGPTL4 are critical lipoprotein lipase (LPL) inhibitors. This review discusses the unique ability of the insulin-responsive protein ANGPTL8 to regulate triglyceride (TG) metabolism by forming ANGPTL3/8 and ANGPTL4/8 complexes that control tissue-specific LPL activities. RECENT FINDINGS: After feeding, ANGPTL4/8 acts locally in adipose tissue, has decreased LPL-inhibitory activity compared to ANGPTL4, and binds tissue plasminogen activator (tPA) and plasminogen to generate plasmin, which cleaves ANGPTL4/8 and other LPL inhibitors. This enables LPL to be fully active postprandially to promote efficient fatty acid (FA) uptake and minimize ectopic fat deposition. In contrast, liver-derived ANGPTL3/8 acts in an endocrine manner, has markedly increased LPL-inhibitory activity compared to ANGPTL3, and potently inhibits LPL in oxidative tissues to direct TG toward adipose tissue for storage. Circulating ANGPTL3/8 levels are strongly correlated with serum TG, and the ANGPTL3/8 LPL-inhibitory epitope is blocked by the TG-lowering protein apolipoprotein A5 (ApoA5). SUMMARY: ANGPTL8 plays a crucial role in TG metabolism by forming ANGPTL3/8 and ANGPTL4/8 complexes that differentially modulate LPL activities in oxidative and adipose tissues respectively. Selective ANGPTL8 inhibition in the context of the ANGPTL3/8 complex has the potential to be a promising strategy for treating dyslipidemia.

Effects of exercise training on ANGPTL3/8 and ANGPTL4/8 and their associations with cardiometabolic traits.

Angiopoietin-like protein (ANGPTL) complexes 3/8 and 4/8 are established inhibitors of LPL and novel therapeutic targets for dyslipidemia. However, the effects of regular exercise on ANGPTL3/8 and ANGPTL4/8 are unknown. We characterized ANGPTL3/8 and ANGPTL4/8 and their relationship with in vivo measurements of lipase activities and cardiometabolic traits before and after a 5-month endurance exercise training intervention in 642 adults from the HERITAGE (HEalth, RIsk factors, exercise Training And GEnetics) Family Study. At baseline, higher levels of both ANGPTL3/8 and ANGPTL4/8 were associated with a worse lipid, lipoprotein, and cardiometabolic profile, with only ANGPTL3/8 associated with postheparin LPL and HL activities. ANGPTL3/8 significantly decreased with exercise training, which corresponded with increases in LPL activity and decreases in HL activity, plasma triglycerides, apoB, visceral fat, and fasting insulin (all P < 5.1 × 10-4). Exercise-induced changes in ANGPTL4/8 were directly correlated to concomitant changes in total cholesterol, LDL-C, apoB, and HDL-triglycerides and inversely related to change in insulin sensitivity index (all P < 7.0 × 10-4). In conclusion, exercise-induced decreases in ANGPTL3/8 and ANGPTL4/8 were related to concomitant improvements in lipase activity, lipid profile, and cardiometabolic risk factors. These findings reveal the ANGPTL3-4-8 model as a potential molecular mechanism contributing to adaptations in lipid metabolism in response to exercise training.

Hepatic fat changes with antisense oligonucleotide therapy targeting ANGPTL3.

BACKGROUND: Angiopoietin-like protein 3 (ANGPTL3) is a novel therapeutic target for hyperlipidemia. Vupanorsen, an antisense oligonucleotide targeting ANGPTL3, reduced triglycerides up to 57% in a phase 2b trial, but caused dose-dependent increases in hepatic fat fraction (HFF). OBJECTIVE: To determine the degree of HFF progression with escalating doses of vupanorsen, differential HFF increases in key patient subgroups, and the correlation between changes in HFF and liver enzymes. METHODS: TRANSLATE-TIMI 70 was a randomized, placebo-controlled trial testing 7 dosing regimens of vupanorsen in 286 adults with hyperlipidemia. A total of 227 patients had HFF measured at baseline and 24 weeks and were included in this analysis. RESULTS: The median HFF at baseline was 8.5%. Vupanorsen led to dose-dependent relative increases in HFF of up to 76% at 24 weeks (p < 0.001), corresponding to an absolute increase of up to 7.0% at the highest dose (p < 0.001). Increases in HFF were numerically greater in patients who had elevated baseline HFF, body mass index, triglycerides, or diabetes. Vupanorsen also increased liver enzymes in a dose-dependent manner, and changes in HFF were moderately positively correlated with changes in aspartate transaminase (AST) (rho = 0.49, p < 0.001) and alanine transaminase (ALT) (rho = 0.50, p < 0.001). CONCLUSION: Vupanorsen, an inhibitor of ANGPTL3 protein synthesis, caused dose-dependent increases in HFF. Increases in HFF were only moderately correlated with elevations in AST and ALT, suggesting that liver enzymes are an imperfect indicator to detect increases in hepatic fat. These results highlight the need to monitor HFF in clinical trials of therapies targeting intracellular ANGPTL3 inhibition, especially those that are targeted to the liver.

The Proinflammatory Role of ANGPTL8 R59W Variant in Modulating Inflammation through NF-κB Signaling Pathway under TNFα Stimulation.

BACKGROUND: Angiopoietin-like protein 8 (ANGPTL8) is known to regulate lipid metabolism and inflammation. It interacts with ANGPTL3 and ANGPTL4 to regulate lipoprotein lipase (LPL) activity and with IKK to modulate NF-κB activity. Further, a single nucleotide polymorphism (SNP) leading to the ANGPTL8 R59W variant associates with reduced low-density lipoprotein/high-density lipoprotein (LDL/HDL) and increased fasting blood glucose (FBG) in Hispanic and Arab individuals, respectively. In this study, we investigate the impact of the R59W variant on the inflammatory activity of ANGPTL8. METHODS: The ANGPTL8 R59W variant was genotyped in a discovery cohort of 867 Arab individuals from Kuwait. Plasma levels of ANGPTL8 and inflammatory markers were measured and tested for associations with the genotype; the associations were tested for replication in an independent cohort of 278 Arab individuals. Impact of the ANGPTL8 R59W variant on NF-κB activity was examined using approaches including overexpression, luciferase assay, and structural modeling of binding dynamics. RESULTS: The ANGPTL8 R59W variant was associated with increased circulatory levels of tumor necrosis factor alpha (TNFα) and interleukin 7 (IL7). Our in vitro studies using HepG2 cells revealed an increased phosphorylation of key inflammatory proteins of the NF-κB pathway in individuals with the R59W variant as compared to those with the wild type, and TNFα stimulation further elevated it. This finding was substantiated by increased luciferase activity of NF-κB p65 with the R59W variant. Modeled structural and binding variation due to R59W change in ANGPTL8 agreed with the observed increase in NF-κB activity. CONCLUSION: ANGPTL8 R59W is associated with increased circulatory TNFα, IL7, and NF-κB p65 activity. Weak transient binding of the ANGPTL8 R59W variant explains its regulatory role on the NF-κB pathway and inflammation.