scholarly journals Polyclonal aptamer libraries as binding entities on a graphene FET based biosensor for the discrimination of apo- and holo- retinol binding protein 4

Author(s):  
Ann-Kathrin Kissmann ◽  
Jakob Andersson ◽  
Heinz Fabian Raber ◽  
Markus Krämer ◽  
Hu Xing ◽  
...  

Oligonucleotide DNA aptamers represent an emergently important class of binding entities towards as different analytes as small molecules or even whole cells. Without the canonical isolation of individual aptamers following the SELEX process already the focused polyclonal libraries prepared by this in vitro evolution and selection can directly be used to label their dedicated analytes and to serve as binding molecules on surfaces. Here we report the first instance of a sensor able to discriminate between loaded and unloaded retinol binding protein 4 (RBP4), an important biomarker for the prediction of diabetes and kidney disease. The sensor relies purely on two aptamer libraries tuned such, that they discriminate between the protein isoforms, requiring no further sample labelling to detect RBP4 in both state. The evolution, binding properties of the libraries and the functionalization of graphene FET sensor chips are presented as well as the functionality of the resulting biosensor.

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Chuyao Jin ◽  
Lizi Lin ◽  
Na Han ◽  
Zhiling Zhao ◽  
Zheng Liu ◽  
...  

Abstract Background To assess the association between plasma retinol-binding protein 4 (RBP4) levels both in the first trimester and second trimester and risk of gestational diabetes mellitus (GDM). Methods Plasma RBP4 levels and insulin were measured among 135 GDM cases and 135 controls nested within the Peking University Birth Cohort in Tongzhou. Multivariable linear regression analysis was conducted to assess the influence of RBP4 levels on insulin resistance. Conditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence interval (CI) between RBP4 levels and risk of GDM. Results The GDM cases had significantly higher levels of RBP4 in the first trimester than controls (medians: 18.0 μg/L vs 14.4 μg/L; P < 0.05). Plasma RBP4 concentrations in the first and second trimester were associated with fasting insulin, homeostasis model assessment for insulin resistance (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI) in the second trimester (all P < 0.001). With adjustment for diet, physical activity, and other risk factors for GDM, the risk of GDM increased with every 1-log μg/L increment of RBP4 levels, and the OR (95% CI) was 3.12 (1.08–9.04) for RBP4 in the first trimester and 3.38 (1.03–11.08) for RBP4 in the second trimester. Conclusions Plasma RBP4 levels both in the first trimester and second trimester were dose-dependently associated with increased risk of GDM.


2021 ◽  
Vol 22 (11) ◽  
pp. 5827
Author(s):  
Jae Chul Lee ◽  
Sung Hoon Kim ◽  
Young Sang Oh ◽  
Ju Hee Kim ◽  
Sa Ra Lee ◽  
...  

Although endometriosis is a benign disease characterized by the presence of endometrial tissues outside the uterus, ectopic endometrial cells can exhibit malignant biological behaviors. Retinol-binding protein4 (RBP4) is a novel adipocyte-derived cytokine, which has important roles in regulating insulin sensitivity and energy metabolism. RBP4 is a potent modulator of gene transcription, and acts by directly controlling cell growth, invasiveness, proliferation and differentiation. Here, we evaluated the possible role of RBP4 in the pathogenesis of endometriosis. We compared the levels of RBP4 in the tissues and peritoneal fluid (PF) of women with and without endometriosis and evaluated the in vitro effects of RBP4 on the viability, invasiveness, and proliferation of endometrial stromal cells (ESCs). RBP4 levels were significantly higher in the PF of the women in the endometriosis group than in the controls. RBP4 immunoreactivity was significantly higher in the ovarian endometriomas of women with advanced stage endometriosis than those of controls. In vitro treatment with human recombinant-RBP4 significantly increased the viability, bromodeoxyuridine expression, and invasiveness of ESCs. Transfection with RBP4 siRNA significantly reduced ESC viability and invasiveness. These findings suggest that RBP4 partakes in the pathogenesis of endometriosis by increasing the viability, proliferation and invasion of endometrial cells.


2021 ◽  
pp. 1-8
Author(s):  
Yuanhao Wu ◽  
Fan Wang ◽  
Tingting Wang ◽  
Yin Zheng ◽  
Li You ◽  
...  

<b><i>Background:</i></b> Arteriovenous fistula (AVF) is the most common vascular access for patients undergoing hemodialysis (HD). Neointimal hyperplasia (NIH) might be a potential mechanism of AVF dysfunction. Retinol-binding protein 4 (RBP4) may play an important role in the pathogenesis of NIH. The aim of this study was to investigate whether AVF dysfunction is associated with serum concentrations of RBP4 in HD subjects. <b><i>Methods:</i></b> A cohort of 65 Chinese patients undergoing maintenance HD was recruited between November 2017 and June 2019. The serum concentrations of RBP4 of each patient were measured with the ELISA method. Multivariate logistic regression was used to analyze data on demographics, biochemical parameters, and serum RBP4 level to predict AVF dysfunction events. The cutoff for serum RBP4 level was derived from the highest score obtained on the Youden index. Survival data were analyzed with the Cox proportional hazards regression analysis and Kaplan-Meier method. <b><i>Results:</i></b> Higher serum RBP4 level was observed in patients with AVF dysfunction compared to those without AVF dysfunction events (174.3 vs. 168.4 mg/L, <i>p</i> = 0.001). The prevalence of AVF dysfunction events was greatly higher among the high RBP4 group (37.5 vs. 4.88%, <i>p</i> = 0.001). In univariate analysis, serum RBP4 level was statistically significantly associated with the risk of AVF dysfunction (OR = 1.015, 95% CI 1.002–1.030, <i>p</i> = 0.030). In multivariate analysis, each 1.0 mg/L increase in RBP4 level was associated with a 1.023-fold-increased risk of AVF dysfunction (95% CI for OR: 1.002–1.045; <i>p</i> = 0.032). The Kaplan-Meier survival analysis indicated that the incidence of AVF dysfunction events in the high RBP4 group was significantly higher than that in the low-RBP4 group (<i>p</i> = 0.0007). Multivariate Cox regressions demonstrated that RBP4 was an independent risk factor for AVF dysfunction events in HD patients (HR = 1.015, 95% CI 1.001–1.028, <i>p</i> = 0.033). <b><i>Conclusions:</i></b> HD patients with higher serum RBP4 concentrations had a relevant higher incidence of arteriovenous dysfunction events. Serum RBP4 level was an independent risk factor for AVF dysfunction events in HD patients.


Amyloid ◽  
2017 ◽  
Vol 24 (sup1) ◽  
pp. 120-121 ◽  
Author(s):  
Marios Arvanitis ◽  
Steven Simon ◽  
Gloria Chan ◽  
Denise Fine ◽  
Paula Beardsley ◽  
...  

Gene ◽  
2013 ◽  
Vol 526 (2) ◽  
pp. 170-175 ◽  
Author(s):  
Hua-Dong Yin ◽  
Elizabeth R. Gilbert ◽  
Shi-Yi Chen ◽  
Di-Yan Li ◽  
Zhi-Chao Zhang ◽  
...  

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