Apolipoprotein A1 and high-density lipoprotein limit low-density lipoprotein transcytosis by binding SR-B1.

Atherosclerosis results from the deposition and oxidation of LDL and immune cell infiltration in the sub-arterial space leading to arterial occlusion. Studies have shown that transcytosis transports circulating LDL across endothelial cells lining blood vessels. LDL transcytosis is initiated by binding to either scavenger receptor B1 (SR-B1) or activin A receptor-like kinase 1 on the apical side of endothelial cells leading to its transit and release on the basolateral side. HDL is thought to partly protect individuals from atherosclerosis due to its ability to remove excess cholesterol and act as an antioxidant. Apolipoprotein A1 (APOA1), an HDL constituent, can bind to SR-B1, raising the possibility that APOA1/HDL can compete with LDL for SR-B1 binding, thereby limiting LDL deposition in the sub-arterial space. To examine this possibility, we used in vitro approaches to quantify the internalization and transcytosis of fluorescent LDL in coronary endothelial cells. Using microscale thermophoresis and affinity capture, we find that SR-B1 and APOA1 interact and that binding is enhanced when using the cardioprotective variant of APOA1 termed Milano (APOA1-Milano). In male mice, transiently increasing the levels of HDL reduced the acute deposition of fluorescently labeled LDL in the atheroprone inner curvature of the aorta. Reduced LDL deposition was also observed when increasing circulating wild-type APOA1 or the APOA1-Milano variant, with a more robust inhibition from the APOA1-Milano. The results suggest that HDL may limit SR-B1-mediated LDL transcytosis and deposition, adding to the mechanisms by which it can act as an atheroprotective particle.

Increased Apolipoprotein A1 Expression Correlates with Tumor-Associated Neutrophils and T Lymphocytes in Upper Tract Urothelial Carcinoma.

An increased neutrophil-to-lymphocyte ratio (NLR) is a poor prognostic biomarker in various types of cancer, because it reflects the inhibition of lymphocytes in the circulation and tumors. In urologic cancers, upper tract urothelial carcinoma (UTUC) is known for its aggressive features and lack of T cell infiltration; however, the association between neutrophils and suppressed T lymphocytes in UTUC is largely unknown. In this study, we examined the relationship between UTUC-derived factors and tumor-associated neutrophils or T lymphocytes. The culture supernatant from UTUC tumor tissue modulated neutrophils to inhibit T cell proliferation. Among the dominant factors secreted by UTUC tumor tissue, apolipoprotein A1 (Apo-A1) exhibited a positive correlation with NLR. Moreover, tumor-infiltrating neutrophils were inversely correlated with tumor-infiltrating T cells. Elevated Apo-A1 levels in UTUC were also inversely associated with the population of tumor-infiltrating T cells. Our findings indicate that elevated Apo-A1 expression in UTUC correlates with tumor-associated neutrophils and T cells. This suggests a potential immunomodulatory effect on neutrophils and T cells within the tumor microenvironment, which may represent therapeutic targets for UTUC treatment.

Low serum apolipoprotein A1 level predicts poor prognosis of patients with diffuse large B-cell lymphoma in the real world: a retrospective study.

BACKGROUND: Apolipoprotein A1 (ApoA1) is a member of the apolipoprotein family with diverse functions. It is associated with the pathogenesis and prognosis of several types of tumors. However, the role of serum apolipoprotein A1 (ApoA1) in the prognosis of patients with diffuse large B-cell lymphoma (DLBCL) remains unclear. This study aimed to elucidate its influence on clinical outcomes in patients with DLBCL. METHODS: We retrospectively analyzed a cohort of 1583 consecutive DLBCL patients admitted to the Fujian Medical University Union Hospital between January 2011 and December 2021. 949 newly diagnosed DLBCL patients who met the inclusion criteria were enrolled for statistical analysis. Receiver operating characteristic curve analysis was performed to determine the optimal cut-off value for serum ApoA1 levels for prognostic prediction among patients with DLBCL. The correlations between serum ApoA1 levels and clinical and laboratory parameters were analyzed. Prognostic significance was analyzed using univariate and multivariate Cox proportional hazards models. RESULTS: Newly diagnosed patients with DLBCL demonstrated low serum ApoA1 levels (< 0.925 g/L), had more B symptoms, higher levels of serum lactate dehydrogenase (LDH) (>upper limit of normal), poorer performance status (Eastern Cooperative Oncology Group score of 2-4), higher percentage of advanced stage and non-germinal center B-cell (non-GCB) subtype, more cases of > 1 extranodal site, higher International Prognostic Index (IPI) score (3-5), and higher incidence of relapse or refractory diseases compared with those with high serum ApoA1 levels (≥ 0.925 g/L). Low serum ApoA1 levels were an independent adverse prognostic factor for overall survival (OS) but not progression-free survival (PFS). CONCLUSIONS: Low serum ApoA1 levels were associated with poor treatment response and inferior survival in newly diagnosed patients with DLBCL.

The neutrophil-to-apolipoprotein A1 ratio is associated with adverse outcomes in patients with acute decompensated heart failure at different glucose metabolic states: a retrospective cohort study.

BACKGROUND: The present study was performed to assess the association between the neutrophil-to-apolipoprotein A1 ratio (NAR) and outcomes in patients with acute decompensated heart failure (ADHF) at different glucose metabolism states. METHODS: We recruited 1233 patients with ADHF who were admitted to Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from December 2014 to October 2019. The endpoints were defined as composites of cardiovascular death, nonfatal myocardial infarction, nonfatal ischemic stroke and exacerbation of chronic heart failure. The restricted cubic spline was used to determine the best cutoff of NAR, and patients were divided into low and high NAR groups. Kaplan-Meier plots and multivariable Cox proportional hazard models were used to investigate the association between NAR and the risk of adverse outcomes. RESULTS: During the five-year follow-up period, the composite outcome occurred in 692 participants (56.1%). After adjusting for potential confounding factors, a higher NAR was associated with a higher incidence of composite outcomes in the total cohort (Model 1: HR = 1.42, 95% CI = 1.22-1.65, P<0.001; Model 2: HR = 1.29, 95% CI = 1.10-1.51, P = 0.002; Model 3: HR = 1.20, 95% CI = 1.01-1.42, P = 0.036). At different glucose metabolic states, a high NAR was associated with a high risk of composite outcomes in patients with diabetes mellitus (DM) (Model 1: HR = 1.54, 95% CI = 1.25-1.90, P<0.001; Model 2: HR = 1.40, 95% CI = 1.13-1.74, P = 0.002; Model 3: HR = 1.31, 95% CI = 1.04-1.66, P = 0.022), and the above association was not found in patients with prediabetes mellitus (Pre-DM) or normal glucose regulation (NGR) (both P>0.05). CONCLUSIONS: The NAR has predictive value for adverse outcomes of ADHF with DM, which implies that the NAR could be a potential indicator for the management of ADHF.

[－75 G/A Polymorphism of Apolipoprotein A1 Gene Promoter Region in Normal Pregnant Women and Patients With Gestational Diabetes Mellitus]. / æ­£å¸¸å­•å¦‡åŠå¦Šå¨ ç³–å°¿ç— æ‚£è€ apoA1åŸºå› å¯åŠ¨å­åŒºï¼75 G/Aå¤šæ€æ€§çš„ç ”ç©¶.

Objective: To investigate the －75 G/A single-nucleotide polymorphism in the promoter region of apolipoprotein A1 gene (apoA1) and its association with gestational diabetes mellitus (GDM) in pregnant women and to provide references for the exploration in the molecular genetic basis of GDM. Methods: A total of 626 GDM patients and 1022 normal pregnant women, ie, the controls, were included in the study. The genotyping of apoA1 －75 G/A polymorphism was performed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose (Glu) were measured by enzymatic methods. Plasma insulin (INS) was measured by chemiluminescence immunoassay. The protein levels of apoA1 and apoB were measured by the turbidimetric immunoassay. Results: Allele frequencies of G and A were 0.718 and 0.282 in the GDM group and 0.713 and 0.287 in the control group, respectively. Distribution of the genotype frequencies was found to be in Hardy-Weinberg equilibrium in both the GDM and control groups. There was no significant difference in the frequencies of alleles G and A and the genotypes of apoA1 －75 G/A polymorphism between the GDM and the control group (P>0.05). In the GDM group, the carriers with the genotype AA were associated with significantly higher levels of TC, HDL-C, and apoA1 than those with genotypes GG and GA did (all P<0.05). After the GDM patients were divided into obese and non-obese subgroups, the genotype-related apoA1 variation was observed only in obese patients, while the genotype-related TC and HDL-C variations were evident in non-obese patients (P<0.05). In the control group, carriers of genotypes AA and GA had higher systolic blood pressure (SBP) and HDL-C than the carriers of genotype GG did (all P<0.05). Carriers of genotypes AA had significantly lower Glu levels than carriers of genotypes GG and GA did (P<0.05). The control subjects were further divided into subgroups according to their body mass index (BMI). Analysis of the subgroups showed that AA carriers were associated with higher SBP levels in the obese control women only, while lower Glu levels were evident in both obese and non-obese control women. Conclusion: These results suggest that －75 G/A polymorphism in the apoA1 gene is not associated with GDM. However, the genetic variation is closed associated with the plasma apoA1, HDL-C, and TC levels in GDM patients and plasma HDL-C, Glu, and SBP levels in the control subjects. The apoA1 variant-associated lipids and SBP variation is BMI dependent in both groups.

Antibody against apolipoprotein-A1, non-alcoholic fatty liver disease and cardiovascular risk: a translational study.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a common liver disease increasing cardiovascular disease (CVD) morbidity and mortality. Autoantibodies against apolipoprotein A-1 (AAA-1) are a possible novel CVD risk factor promoting inflammation and disrupting cellular lipid homeostasis, two prominent pathogenic features of NAFLD. We explored the role of AAA-1 in NAFLD and their association with CVD risk. METHODS: HepaRG cells and liver sections from ApoE-/- mice exposed to AAA-1 were used for lipid quantification and conditional protein expression. Randomly selected sera from 312 subjects of the Prevention of Renal and Vascular End-stage Disease (PREVEND) general population cohort were used to measure AAA-1. A Fatty Liver Index (FLI) ≥ 60 and a 10-year Framingham Risk Score (FRS) ≥ 20% were used as proxy of NAFLD and high CVD risk, respectively. RESULTS: In-vitro and mouse models showed that AAA-1 increased triglyceride synthesis leading to steatosis, and promoted inflammation and hepatocyte injury. In the 112 PREVEND participants with FLI ≥ 60, AAA-1 were associated with higher FRS, alkaline phosphatase levels, lower HDL cholesterol and tended to display higher FLI values. Univariate linear and logistic regression analyses (LRA) confirmed significant associations between AAA-1, FLI and FRS ≥ 20%, while in adjusted LRA, FLI was the sole independent predictor of FRS ≥ 20% (OR: 1.05, 95%CI 1.01-1.09, P = 0.003). AAA-1 was not an independent FLI predictor. CONCLUSIONS: AAA-1 induce a NAFLD-compatible phenotype in vitro and in mice. Intricate associations exist between AAA-1, CVD risk and FLI in the general population. Further work is required to refine the role of AAA-1 in NAFLD and to determine if the AAA-1 association with CVD is affected by hepatic steatosis.

Association between serum apolipoprotein A1 and atrial fibrillation in the Chinese population: a case-control study.

BACKGROUND: The relationship between serum apolipoprotein A1 (APOA1) and atrial fibrillation (AF) is not known. Therefore, we sought to investigate the associations between APOA1 and AF in the Chinese population. METHODS: This case-control study included 950 patients with AF (29-83 years old, 50.42% male) who were hospitalized consecutively in China between January 2019 and September 2021. Controls with sinus rhythm and without AF were matched (1:1) to cases by sex and age. Pearson correlation analysis was performed to investigate the correlation between APOA1 and blood lipid profiles. Multivariate regression models were used to explore the association between APOA1 and AF. The receiver operator characteristic (ROC) curve was constructed to examine the performance of APOA1. RESULTS: Multivariate regression analysis showed that low serum APOA1 in men and women with AF was significantly associated with AF (OR = 0.261, 95% CI: 0.162-0.422, P < 0.001). Pearson correlation analysis indicated that serum APOA1 was positively correlated with total cholesterol (TC) (r = 0.456, p < 0.001), low-density lipoprotein cholesterol (LDL-C) (r = 0.825, p < 0.001), high-density lipoprotein cholesterol (HDL-C) (r = 0.238, p < 0.001), and apolipoprotein B (APOB) (r = 0.083, p = 0.011). ROC curve analysis showed that APOA1 levels of 1.105 g/L and 1.205 g/L were the optimal cut-off values for predicting AF in males and females, respectively. CONCLUSION: Low APOA1 in male and female patients is significantly associated with AF in the Chinese population of non-statin users. APOA1 may be a potential biomarker for AF and contribute to the pathological progression of AF along with low blood lipid profiles. Potential mechanisms remain to be further explored.

Association of apolipoprotein A1 with osteoporosis: a cross-sectional study.

Higher levels of apolipoprotein A1 (ApoA1) were associated with higher risk of osteoporosis, which supports the argument that lipid metabolism is involved in bone metabolism. BACKGROUND: Although the current evidence shows that lipid metabolism and osteoporosis are closely related to cardiovascular disease, the association between ApoA1 and osteoporosis is still unknown. Therefore, the purpose of this study was to explore the relationship between ApoA1 and osteoporosis. METHODS: In this cross-sectional study, we included 7743 participants in the Third National Health and Nutrition Examination Survey. ApoA1 was regarded as an exposure variable and osteoporosis was considered as an outcome variable. Multivariate logistic regression analysis, sensitivity analysis, and receiver operator characteristic (ROC) were used to assess the association of ApoA1 with osteoporosis. RESULTS: Participants with higher ApoA1 had higher rates of osteoporosis compared to participants with lower ApoA1 (P <  0.05). Individuals with osteoporosis had higher levels of ApoA1 than individuals without osteoporosis (P <  0.05). In multivariate logistic regression analysis adjusted for age, sex, race, hypertension, diabetes, gout, hypotensive drugs, hypoglycemic drugs, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein B, blood urea nitrogen, albumin, uric acid, hemoglobin A1c, alkaline phosphatase and total calcium, higher ApoA1 was strongly associated with higher risk of osteoporosis, whether as a continuous variable or a categorical variable [Model 3, OR (95% CI), P value: 2.289 (1.350, 3.881), 0.002 and 1.712 (1.183, 2.478), 0.004]. And after excluding individuals with gout, the correlation between them remained and was significant (P <  0.01). And ROC analysis also showed that ApoA1 could predict the development of osteoporosis (AUC = 0.650, P <  0.001). CONCLUSION: ApoA1 was closely associated with osteoporosis.

APOA1 Is a Novel Marker for Preeclampsia.

Preeclampsia (PE) is one of the pregnancy complications, leading to major maternal and fetal morbidity and mortality; however, the underlying mechanisms of PE still remain unclear. We aimed to explore the role of apolipoprotein A1 (APOA1) in the pathophysiology of PE. The expression of APOA1 was elevated in both plasma and placental tissues, as detected by Western blotting, immunohistochemistry, and a qRT-PCR assay. Importantly, we detected the concentration of APOA1 using the ELISA assay in normal control women (n = 30) and women with preeclampsia (n = 29) from a prospective cohort study. The concentration of APOA1 was not significantly altered in plasma during early and mid-term gestation of the PE patients compared to the NP patients; however, it was elevated during late gestation. Additionally, the concentration of APOA1 was positively associated with systolic blood pressure during late gestation. The proliferation and invasion of trophoblast were all increased in HTR8/SVneo cells transfected with APOA1 siRNA and decreased in HTR8/SVneo cells treated with the recombinant human APOA1 protein (rhAPOA1). Additionally, we used public datasets to investigate the downstream genes of APOA1 and qRT-PCR for validation. Furthermore, we explored the transcriptional activity of peroxisome proliferator-activated receptor gamma (PPARγ) in APOA1 by using a luciferase assay, which showed that the APOA1 promoter was activated by PPARγ. Additionally, the inhibitory effect of rhAPOA1 on the ability of trophoblast invasion and proliferation can be rescued by the PPARγ inhibitor. Our findings suggest the crucial role of APOA1 in PE, which might provide a new strategy for the prevention and treatment of PE.

BAL Proteomic Signature of Lung Adenocarcinoma in IPF Patients and Its Transposition in Serum Samples for Less Invasive Diagnostic Procedures.

Idiopathic pulmonary fibrosis (IPF) is a form of chronic and irreversible fibrosing interstitial pneumonia of unknown etiology. Although antifibrotic treatments have shown a reduction of lung function decline and a slow disease progression, IPF is characterize by a very high mortality. Emerging evidence suggests that IPF increases the risk of lung carcinogenesis. Both diseases show similarities in terms of risk factors, such as history of smoking, concomitant emphysema, and viral infections, besides sharing similar pathogenic pathways. Lung cancer (LC) diagnosis is often difficult in IPF patients because of the diffuse lung injuries and abnormalities due to the underlying fibrosis. This is reflected in the lack of optimal therapeutic strategies for patients with both diseases. For this purpose, we performed a proteomic study on bronchoalveolar lavage fluid (BALF) samples from IPF, LC associated with IPF (LC-IPF) patients, and healthy controls (CTRL). Molecular pathways involved in inflammation, immune response, lipid metabolism, and cell adhesion were found for the dysregulated proteins in LC-IPF, such as TTHY, APOA1, S10A9, RET4, GDIR1, and PROF1. The correlation test revealed a relationship between inflammation- and lipid metabolism-related proteins. PROF1 and S10A9, related to inflammation, were up-regulated in LC-IPF BAL and serum, while APOA1 and APOE linked to lipid metabolism, were highly abundant in IPF BAL and low abundant in IPF serum. Given the properties of cytokine/adipokine of the nicotinamide phosphoribosyltransferase, we also evaluated its serum abundance, highlighting its down-regulation in LC-IPF. Our retrospective analyses of BAL samples extrapolated some potential biomarkers of LC-IPF useful to improve the management of these contemporary pathologies. Their differential abundance in serum samples permits the measurement of these potential biomarkers with a less invasive procedure.

Follicular Fluid Proteomic Analysis of Women Undergoing Assisted Reproduction Suggests That Apolipoprotein A1 Is a Potential Fertility Marker.

Infertility affects millions worldwide, posing a significant global health challenge. The proteomic analysis of follicular fluid provides a comprehensive view of the complex molecular landscape within ovarian follicles, offering valuable information on the factors influencing oocyte development and on the overall reproductive health. The follicular fluid is derived from the plasma and contains various proteins that can have different roles in oocyte health and infertility, and this fluid is a critical microenvironment for the developing oocytes as well. Using the high-performance liquid chromatography-mass spectrometry method, we investigated the protein composition of the follicular fluid, and after classification, we carried out relative quantification of the identified proteins in the pregnant (P) and non-pregnant (NP) groups. Based on the protein-protein interaction analysis, albumin and apolipoprotein A1 (ApoA1) were found to be hub proteins, and the quantitative comparison of the P and NP groups resulted in a significantly lower concentration of ApoA1 and high-density lipoprotein cholesterol in the P group. As both molecules are involved in the cholesterol transport, we also investigated their role in the development of oocytes and in the prediction of fertility.

Low apolipoprotein A1 was associated with increased risk of cancer mortality in patients following percutaneous coronary intervention: A 10-year follow-up study.

Previous studies showed that elevated apolipoprotein A1 (ApoA1) and high-density lipoprotein cholesterol (HDL-C) predicted reduced risk of cardiovascular-related (CV) mortality in patients following percutaneous coronary intervention (PCI). Nevertheless, as the association between ApoA1 and cancer mortality in this population has been rarely addressed, our study aimed to evaluate prognostic impact of ApoA1 on multiple types of cancer mortality after PCI. This is a retrospective analysis of a single-center prospective registry database of patients who underwent PCI between 2000 and 2018. The present study enrolled 3835 patients whose data of serum ApoA1 were available and they were divided into three groups according to the tertiles of the preprocedural level of ApoA1. The outcome measures were total, gastrointestinal, and lung cancer mortalities. The median and range of the follow-up period between the index PCI and latest follow-up were 5.9 and 0-17.8 years, respectively. Consequently, Kaplan-Meier analyses showed significantly higher rates of the cumulative incidences of total, gastrointestinal, and lung cancer mortality in the lowest ApoA1 tertile group compared to those in the highest. In contrast, there were no significant differences in all types of cancer mortality rates in the groups divided by the tertiles of HDL-C. Multivariable Cox proportional hazard regression analysis adjusted by cancer-related prognostic factors, such as smoking status, identified the elevated ApoA1 as an independent predictor of decreased risk of total and gastrointestinal cancer mortalities. Our study demonstrates the prognostic implication of preprocedural ApoA1 for predicting future risk of cancer mortality in patients undergoing PCI.

Circulating lipids and breast cancer prognosis in the Malmö diet and cancer study.

PURPOSE: Examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). PATIENTS AND METHODS: Circulating lipid levels were measured in blood sampled upon enrollment in the female MDCS cohort (N = 17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991 and 2014. Follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or 5 years of follow-up. We estimated the incidence rates of recurrence at 5 years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). RESULTS: We enrolled 850 eligible patients. During the 5 years of follow-up, 90 invasive breast cancer recurrences were diagnosed over 3807 person-years. In multivariable analyses, high baseline levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR = 2.30 [95% CI 1.13-4.68]). However, high baseline levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR = 1.23 [95% CI 0.68-2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR = 1.34 [95% CI 0.70-2.58]) or all-cause mortality (tertile 3 vs. 1, HR = 1.12 [95% CI 0.61-2.05]). CONCLUSION: High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcomes.

ApoA1 Neutralizes Proinflammatory Effects of Dengue Virus NS1 Protein and Modulates Viral Immune Evasion.

Dengue is a mosquito-borne infectious disease that is highly endemic in tropical and subtropical countries. Symptomatic patients can rapidly progress to severe conditions of hemorrhage, plasma extravasation, and hypovolemic shock, which leads to death. The blood tests of patients with severe dengue typically reveal low levels of high-density lipoprotein (HDL), which is responsible for reverse cholesterol transport (RCT) and regulation of the lipid composition in peripheral tissues. It is well known that dengue virus (DENV) depends on membrane cholesterol rafts to infect and to replicate in mammalian cells. Here, we describe the interaction of DENV nonstructural protein 1 (NS1) with apolipoprotein A1 (ApoA1), which is the major protein component of HDL. NS1 is secreted by infected cells and can be found circulating in the serum of patients with the onset of symptoms. NS1 concentrations in plasma are related to dengue severity, which is attributed to immune evasion and an acute inflammatory response. Our data show that the DENV NS1 protein induces an increase of lipid rafts in noninfected cell membranes and enhances further DENV infection. We also show that ApoA1-mediated lipid raft depletion inhibits DENV attachment to the cell surface. In addition, ApoA1 is able to neutralize NS1-induced cell activation and to prevent NS1-mediated enhancement of DENV infection. Furthermore, we demonstrate that the ApoA1 mimetic peptide 4F is also capable of mediating lipid raft depletion to control DENV infection. Taken together, our results suggest the potential of RCT-based therapies for dengue treatment. These results should motivate studies to assess the importance of RCT in DENV infection in vivo. IMPORTANCE DENV is one of the most relevant mosquito-transmitted viruses worldwide, infecting more than 390 million people every year and leading to more than 20 thousand deaths. Although a DENV vaccine has already been approved, its potential side effects have hampered its use in large-scale immunizations. Therefore, new treatment options are urgently needed to prevent disease worsening or to improve current clinical management of severe cases. In this study, we describe a new interaction of the NS1 protein, one of the major viral components, with a key component of HDL, ApoA1. This interaction seems to alter membrane susceptibility to virus infection and modulates the mechanisms triggered by DENV to evade the immune response. We also propose the use of a mimetic peptide named 4F, which was originally developed for atherosclerosis, as a potential therapy for relieving DENV symptoms.

Anti-SARS-CoV-2 mRNA vaccines as inducers of humoral response against apolipoprotein A-1?

BACKGROUND: COVID-19 and some anti-SARS-CoV-2 vaccines trigger a humoral autoimmune response against a broad range of endogenous components, which may affect recipients' prognosis in predisposed individuals. Autoantibodies directed against apolipoprotein A-1 (AAA1 IgG) the major protein fraction of High Density Lipoprotein have been shown to be raised in COVID-19 and in rheumatoid arthritis (RA) patients and other populations where they have been associated with poorer outcomes. We wanted to assess the impact of anti-SARS-CoV-2 mRNA-based vaccination on AAA1 autoimmune biomarkers in RA patients. METHODS: 20 healthy controls and 77 RA mRNA-based vaccinated patients were collected at baseline, 3 weeks after the first vaccination, 2 and 8 weeks after the second vaccination. AAA1 and SARS-CoV-2 serologies were measured by immunoassays. Systemic and local symptoms occurring during the vaccination protocol were recorded. RESULTS: mRNA-based vaccination induced a significant increase in median AAA1 IgG levels in both healthy controls and RA patients overtime. However, in both populations, these medians trend did not translate into significant increase in AAA1 IgG seropositivity rates despite evolving from 5 to 10% in healthy controls, and from 9 to 12.9% in RA patients. No associations were retrieved between AAA1 IgG and symptoms of any kind during the vaccination protocol. CONCLUSIONS: mRNA-based vaccination seems to induce a light AAA1 IgG response in immunocompetent individuals within 2 months after the last injection. Although we did not observe any warning signs, the formal demonstration of the harmlessness of such biological warrants further studies.

Autoantibodies against apolipoprotein A-1 after COVID-19 predict symptoms persistence.

BACKGROUND: SARS-CoV-2 infection triggers different auto-antibodies, including anti-apolipoprotein A-1 IgGs (AAA1), which could be of concern as mediators of persistent symptoms. We determined the kinetics of AAA1 response over after COVID-19 and the impact of AAA1 on the inflammatory response and symptoms persistence. METHODS: All serologies were assessed at one, three, six and twelve months in 193 hospital employees with COVID-19. ROC curve analyses and logistic regression models (LRM) were used to determine the prognostic accuracy of AAA1 and their association with patient-reported COVID-19 symptoms persistence at 12 months. Interferon (IFN)-α and-γ production by AAA1-stimulated human monocyte-derived macrophages (HMDM) was assessed in vitro. RESULTS: AAA1 seropositivity was 93% at one month and declined to 15% at 12 months after COVID-19. Persistent symptoms at 12 months were observed in 45.1% of participants, with a predominance of neurological (28.5%), followed by general (15%) and respiratory symptoms (9.3%). Over time, strength of correlations between AAA1 and anti-SARS-COV2 serologies decreased, but remained significant. From the 3rd month on, AAA1 levels predicted persistent respiratory symptoms (area under the curves 0.72-0.74; p < 0.001), independently of disease severity, age and gender (adjusted odds ratios 4.81-4.94; p = 0.02), while anti-SARS-CoV-2 serologies did not. AAA1 increased IFN-α production by HMDMs (p = 0.03), without affecting the IFN-γ response. CONCLUSION: COVID-19 induces a marked though transient AAA1 response, independently predicting one-year persistence of respiratory symptoms. By increasing IFN-α response, AAA1 may contribute to persistent symptoms. If and how AAA1 levels assessment could be of use for COVID-19 risk stratification remains to be determined.

Role of APOA1 in the resistance to platinum-based chemotherapy in squamous cervical cancer.

BACKGROUND: To investigate the mechanism by which apolipoprotein A1 (APOA1) enhances the resistance of cervical squamous carcinoma to platinum-based chemotherapy. METHODS: Two cervical squamous carcinoma cell lines (SiHa and Caski) overexpressing APOA1 were constructed, treated with carboplatin, and compared to normal control cells. RESULTS: In both SiHa and Caski cell lines, the clone-forming ability of CBP-treated cells was lower than that of untreated cells, and the change in the number of clones of overexpressing cells was lower than that of normal control cells (p < 0.05), indicating that APOA1 overexpression enhanced chemoresistance. A screen for APOA1 downstream proteins affecting platinum-based chemoresistance using Tandem Mass Tag revealed 64 differentially expressed proteins in SiHa cells, which were subjected to Gene Ontology (annotation, Kyoto Encyclopedia of Genes and Genomes enrichment, subcellular localization, structural domain annotation and enrichment, clustering, and interaction network analyses. Sixty-four differentially expressed proteins matching cancer-relavent association terms were screened and parallel response monitoring identified 29 proteins as possibly involved in the mechanism of platinum-based chemoresistance. CONCLUSIONS: Our analysis suggested that the mechanism may involve numerous regulatory pathways, including promoting tumor growth via the p38 MAPK signaling pathway through STAT1, promoting tumor progression via the PI3K signaling pathway through CD81 and C3, and promoting resistance to platinum-based chemotherapy resistance through TOP2A. The present study aimed to preliminarily explore the function and mechanism of APOA1 in platinum-based chemoresistance in cervical cancer, and the detailed mechanism needs to be further studied.

Predictive value of preoperative platelet-to-albumin ratio and apolipoprotein B-to-apolipoprotein A1 ratio for osteosarcoma in children and adolescents: a retrospective study of 118 cases.

BACKGROUND: This retrospective study investigated biomarkers that can reflect coagulation, inflammation, and lipid abnormalities: platelet-to-albumin ratio (PAR), platelet-to lymphocyte ratio (PLR), low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (LDL-C/HDL-C), apolipoprotein B-to-apolipoprotein ratio (ApoB/ApoA1) whether may be viable prognostic predictors in children and adolescents with osteosarcoma. METHODS: The retrospective review has enrolled a total of 118 children and adolescent patients diagnosed with osteosarcoma. Analyses with a receiver operating characteristic (ROC) curve were performed to evaluate the optimal cut-off values and to compare the area under curves (AUC). Kaplan-Meier curves were used to visualize survival outcome and a Cox proportional hazards model were used to confirm independent prognostic factors. RESULTS: Osteosarcoma patients in high PAR group (> 4.41) and high ApoB/ApoA1 group (> 0.82) experienced significantly shorter overall survival compared with those in low PAR group (≤ 4.41) and low ApoB/ApoA1 group (≤ 0.82). In univariate and multivariable analyses, preoperative PAR and ApoB/ApoA1 were identified as independent prognostic factors for OS in children and adolescents with osteosarcoma. CONCLUSION: Preoperative PAR and ApoB/ApoA1 can be used as promising predictors in children and adolescents with osteosarcoma to help clinicians recognize patients with an increased risk of poor prognosis.

Adiponectin Stimulates Apolipoprotein A-1 Gene Expression in HepG2 Cells via AMPK, PPARα, and LXRs Signaling Mechanisms.

Adiponectin is an adipose tissue hormone, participating in energy metabolism and involved in atherogenesis. Previously, it was found that adiponectin increases expression of the APOA1 (apolipoprotein A-1) gene in hepatocytes, but the mechanisms of this effect remained unexplored. Our aim was to investigate the role of adiponectin receptors AdipoR1/R2, AMP-activated protein kinase (AMPK), nuclear peroxisome proliferator-activated receptor alpha (PPARα) and liver X receptors (LXRs) in mediating the action of adiponectin on hepatic APOA1 expression in human hepatoma HepG2 cells. The level of APOA1 expression was determined by RT-qPCR and ELISA. We showed that the siRNA-mediated knockdown of genes coding for AdipoR1, AdipoR2, AMPK, PPARα, and LXRα and ß prevented adiponectin-induced APOA1 expression in HepG2 cells and demonstrated that interaction of PPARα and LXRs with the APOA1 gene hepatic enhancer is important for the adiponectin-dependent APOA1 transcription. The results of this study point out to the involvement of both types of adiponectin receptors, AMPK, PPARα, and LXRs in the adiponectin-dependent upregulation of the APOA1 expression.

Inhibition of human sperm function by an antibody against apolipoprotein A1: A protein located in human spermatozoa.

Apolipoproteins A1 (ApoA1), an important protein in initiating sperm capacitation, has been found in the oviduct liquid, whilst whether it expresses in human spermatozoa has not yet been defined. ApoA1 expression was detected by reverse transcription-polymerase chain reaction, Western blot and immunofluorescence in sperm cells. Sperms were incubated with different concentration of ApoA1 antibody to observe the changes of sperm motility and apoptosis including annexin V binding to the cell surface, mitochondrial membrane potential and ultrastructural changes. In addition, cholesterol levels of human spermatozoa and fertilization in vitro were completed to explore the role of ApoA1 in fertilization process. We identify ApoA1 mRNA is presented in spermatozoa, and the ApoA1 protein, the molecular weights of 31 kD, is located at the postacrosomal region and neck of human spermatozoa. ApoA1 antibody affects cholesterol efflux of human spermatozoa and inhibits fertilization in vitro. Moreover, ApoA1 antibody decreases sperm motility and increases sperm apoptosis. This work shows ApoA1 plays an important role in maintaining cholesterol stability and sperm motility, survival rate and fertilization process. Furthermore, ApoA1 implications in the clinical work and other reproductive areas are needed to be studied.