Ultrafast universal fabrication of configurable porous silicone-based elastomers by Joule heating chemistry.

Silicone-based elastomers (SEs) have been extensively applied in numerous cutting-edge areas, including flexible electronics, biomedicine, 5G smart devices, mechanics, optics, soft robotics, etc. However, traditional strategies for the synthesis of polymer elastomers, such as bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization, are inevitably restricted by long-time usage, organic solvent additives, high energy consumption, and environmental pollution. Here, we propose a Joule heating chemistry method for ultrafast universal fabrication of SEs with configurable porous structures and tunable components (e.g., graphene, Ag, graphene oxide, TiO2, ZnO, Fe3O4, V2O5, MoS2, BN, g-C3N4, BaCO3, CuI, BaTiO3, polyvinylidene fluoride, cellulose, styrene-butadiene rubber, montmorillonite, and EuDySrAlSiOx) within seconds by only employing H2O as the solvent. The intrinsic dynamics of the in situ polymerization and porosity creation of these SEs have been widely investigated. Notably, a flexible capacitive sensor made from as-fabricated silicone-based elastomers exhibits a wide pressure range, fast responses, long-term durability, extreme operating temperatures, and outstanding applicability in various media, and a wireless human-machine interaction system used for rescue activities in extreme conditions is established, which paves the way for more polymer-based material synthesis and wider applications.

Robust Ionics Reinforced Fiber As Implantable Sensor for Early Operando Monitoring Cell Thermal Safety of Commercial Lithium-Ion Batteries.

Commercial batteries have been largely applied in mobile electronics, electric vehicles, and scalable energy storage systems. However, thermal runaway of batteries still obstructs the reliability of electric equipment. Considering this, building upon recent investigations of energy thermal safety, commercially available organogel fiber-based implantable sensors have been developed through 3D printing technology for first operando implantable monitoring of cell temperature. The printed fibers present excellent reliability and superelasticity because of internal supramolecular cross-linking. High temperature sensitivity (-39.84% °C-1/-1.557% °C-1) within a wide range (-15 to 80 °C) is achieved, and the corresponding mechanism is clarified based on in situ temperature-dependent Raman technology. Furthermore, taking the pouch cell as an example, combined with finite element analysis, the real-time observation system of cell temperature is successfully demonstrated through an implanted sensor with wireless Bluetooth transmission. This enlightening approach paves the way for achieving safety monitoring and smart warnings for various electric equipment.

Photoinduced Selective B-H Activation of nido-Carboranes.

The development of new synthetic methods for B-H bond activation has been an important research area in boron cluster chemistry, which may provide opportunities to broaden the application scope of boron clusters. Herein, we present a new reaction strategy for the direct site-selective B-H functionalization of nido-carboranes initiated by photoinduced cage activation via a noncovalent cage···π interaction. As a result, the nido-carborane cage radical is generated through a single electron transfer from the 3D nido-carborane cage to a 2D photocatalyst upon irradiation with green light. The resulting transient nido-carborane cage radical could be directly probed by an advanced time-resolved EPR technique. In air, the subsequent transformations of the active nido-carborane cage radical have led to efficient and selective B-N, B-S, and B-Se couplings in the presence of N-heterocycles, imines, thioethers, thioamides, and selenium ethers. This protocol also facilitates both the late-stage modification of drugs and the synthesis of nido-carborane-based drug candidates for boron neutron capture therapy (BNCT).

TaCHP encoding C1-domain protein stably enhances wheat yield in saline-alkaline fields.

Overexpression of the zinc finger gene TaCHP stably enhanced wheat yield in saline-alkaline conditions in a multi-year, three-site field trial, and the genetic variations in its promoter contribute to saline-alkaline tolerance of wheat accessions. TaCHP and its tolerant haplotype have great potential for molecular breeding of stress-tolerant wheat.

Thrombectomy alone vs thrombectomy with over 2/3-dose intravenous thrombolysis pretreatment in the DIRECT-MT trial.

BACKGROUND: The DIRECT-MT trial showed that endovascular thrombectomy (EVT) alone was noninferior to EVT preceded by intravenous alteplase. However, the infusion of intravenous alteplase was uncompleted before the initiation of EVT in most cases of this trial. Therefore, the additional benefit and risk of over 2/3-dose intravenous alteplase pretreatment remain to be assessed. METHODS: We assessed patients with acute anterior circulation ischemic stroke who received EVT alone or with over 2/3-dose intravenous alteplase pretreatment from the DIRECT-MT trial. Patients were assigned to the thrombectomy-alone group and the alteplase pretreatment group. The primary outcome was the distribution of modified Rankin Scale (mRS) at 90 days. The interaction of treatment allocation and collateral capacity was assessed. RESULTS: A total of 393 patients (thrombectomy alone: 315; alteplase pretreatment: 78) were identified. The thrombectomy alone was comparable with alteplase pretreatment prior to the thrombectomy on the distribution of mRS at 90 days without significant effect modification by collateral capacity (adjusted common odds ratio (acOR), 1.12; 95% CI, 0.72-1.74; adjusted P for interaction = 0.83). Successful reperfusion before thrombectomy and the number of passes in the thrombectomy alone group differed significantly from the alteplase pretreatment group (2.6% vs. 11.5%; corrected P = 0.02 and 2 vs. 1; corrected P = 0.003). There was no interaction between treatment allocation and collateral capacity on all outcomes. CONCLUSIONS: EVT alone and EVT preceded by over 2/3-dose intravenous alteplase might have equal efficacy and safety for patients with acute anterior circulation large vessel occlusion, except for successful perfusion before thrombectomy and the number of passes.

Screening of Therapeutic Targets for Pancreatic Cancer by Bioinformatics Methods.

Pancreatic cancer (PC) has the lowest survival rate and the highest mortality rate among all cancers due to lack of effective treatments. The objective of the current study was to identify potential therapeutic targets in PC. Three transcriptome datasets, namely GSE62452, GSE46234, and GSE101448, were analyzed for differentially expressed genes (DEGs) between cancer and normal samples. Several bioinformatics methods, including functional analysis, pathway enrichment, hub genes, and drugs were used to screen therapeutic targets for PC. Fisher's exact test was used to analyze functional enrichments. To screen DEGs, the paired t-test was employed. The statistical significance was considered at p <0.05. Overall, 60 DEGs were detected. Functional enrichment analysis revealed enrichment of the DEGs in "multicellular organismal process", "metabolic process", "cell communication", and "enzyme regulator activity". Pathway analysis demonstrated that the DEGs were primarily related to "Glycolipid metabolism", "ECM-receptor interaction", and "pathways in cancer". Five hub genes were examined using the protein-protein interaction (PPI) network. Among these hub genes, 10 known drugs targeted to the CPA1 gene and CLPS gene were found. Overall, CPA1 and CLPS genes, as well as candidate drugs, may be useful for PC in the future.

Engineering Streptomyces albulus to enhance ε-poly-L-lysine production by introducing a polyphosphate kinase-mediated ATP regeneration system.

BACKGROUND: ε-Poly-L-lysine (ε-PL) is a natural and safe food preservative that is mainly produced by filamentous and aerobic bacteria Streptomyces albulus. During ε-PL biosynthesis, a large amount of ATP is used for the polymerization of L-lysine. A shortage of intracellular ATP is one of the major factors limiting the increase in ε-PL production. In previous studies, researchers have mainly tried to increase the oxygen supply to enhance intracellular ATP levels to improve ε-PL production, which can be achieved through the use of two-stage dissolved oxygen control, oxygen carriers, heterologous expression of hemoglobin, and supplementation with auxiliary energy substrates. However, the enhancement of the intracellular ATP supply by constructing an ATP regeneration system has not yet been considered. RESULTS: In this study, a polyphosphate kinase (PPK)-mediated ATP regeneration system was developed and introduced into S. albulus to successfully improve ε-PL production. First, polyP:AMP phosphotransferase (PAP) from Acinetobacter johnsonii was selected for catalyzing the conversion of AMP into ADP through an in vivo test. Moreover, three PPKs from different microbes were compared by in vitro and in vivo studies with respect to catalytic activity and polyphosphate (polyP) preference, and PPK2Bcg from Corynebacterium glutamicum was used for catalyzing the conversion of ADP into ATP. As a result, a recombinant strain PL05 carrying coexpressed pap and ppk2Bcg for catalyzing the conversion of AMP into ATP was constructed. ε-PL production of 2.34 g/L was achieved in shake-flask fermentation, which was an increase of 21.24% compared with S. albulus WG608; intracellular ATP was also increased by 71.56%. In addition, we attempted to develop a dynamic ATP regulation route, but the result was not as expected. Finally, the conditions of polyP6 addition were optimized in batch and fed-batch fermentations, and the maximum ε-PL production of strain PL05 in a 5-L fermenter was 59.25 g/L by fed-batch fermentation, which is the highest ε-PL production reported in genetically engineered strains. CONCLUSIONS: In this study, we proposed and developed a PPK-mediated ATP regeneration system in S. albulus for the first time and significantly enhanced ε-PL production. The study provides an efficient approach to improve the production of not only ε-PL but also other ATP-driven metabolites.

Understanding the Streptomyces albulus response to low-pH stress at the interface of physiology and transcriptomics.

Streptomyces albulus is a well-established cell factory for ε-poly-L-lysine (ε-PL) production. It has been reported that ε-PL biosynthesis is strictly regulated by pH and that ε-PL can accumulate at approximately pH 4.0, which is outside of the general pH range for natural product production by Streptomyces species. However, how S. albulus responds to low pH is not clear. In this study, we attempted to explore the response of S. albulus to low-pH stress at the physiological and global gene transcription levels. At the physiological level, S. albulus maintained intracellular pH homeostasis at ~pH 7.5, increased the unsaturated fatty acid ratio, extended the fatty acid chain length, enhanced ATP accumulation, increased H+-ATPase activity, and accumulated the basic amino acids L-lysine and L-arginine. At the global gene transcription level, carbohydrate metabolism, oxidative phosphorylation, macromolecule protection and repair, and the acid tolerance system were found to be involved in combating low-pH stress. Finally, we preliminarily evaluated the effect of the acid tolerance system and cell membrane fatty acid synthesis on low-pH tolerance via gene manipulation. This work provides new insight into the adaptation mechanism of Streptomyces to low-pH stress and a new opportunity for constructing robust S. albulus strains for ε-PL production. KEY POINTS: • S. albulus consistently remained pH i at ~7.4 regardless of the environmental pH. • S. albulus combats low-pH stress by modulating lipid composition of cell membrane. • Overexpression of cfa in S. albulus could improve low-pH tolerance and ɛ-PL titer.

Photocatalytic degradation of multiple-organic-pollutant under visible light by graphene oxide modified composite: degradation pathway, DFT calculation and mechanism.

Wastewater containing antibiotics, organic dyes, and waterborne bacteria is a severe threat to human health and the environment. Amoxicillin has a slow metabolism rate in humans. Methylene blue is mutagenic and carcinogenic. In addition, Salmonella causes serious diarrhea. In this study, an effective 2D/2D photocatalyst with excellent elimination of these pollutants was fabricated by combining graphene oxide (GO), Bi2WO6, BiPO4 and Ag species. GO was applied at varying loading contents (0.8, 1.6, 2.4, 3.2 wt%) to improve the properties of the photocatalyst toward the removal of representative pollutants. The chemical structures, morphology, light absorption and charge mobility were investigated by different GO loading samples. The results indicated that when the wt% of GO was 2.4%, the photocatalyst showed excellent photocatalytic properties and removal rates for typical pollutants. Amoxicillin and methylene blue were mineralized into CO2, H2O, and small molecules, while Salmonella was disinfected with excellent photocatalytic efficiency. Furthermore, the possible photodecomposition pathways of amoxicillin and methylene blue were proposed by DFT calculations and intermediates identified by LCMS. The mechanism of the photocatalytic process was investigated by radical trapping experiments, ESR spectroscopy, and Motty-Schottky plots. The free radicals could be produced constantly during the photocatalytic process, leading to mineralization of amoxicillin and methylene blue, and disinfection of Salmonella. In this work, a new perspective on GO modified Bi2WO6 with different loading contents and the degradation pathways of antibiotics and dyes was proposed.

Quantitative scattering models of broad-band narrow-beam light through fog.

A quantitative understanding about the optical scattering of medium plays an important role in many common but important application fields including optical imaging, optical communication, and optical remote sensing. In this paper, two quantitative models about single scattering and multiple scattering were established based on the different polarization properties of these two scattering processes on the condition of paraxial approximation. The related approximate explicit functions about the light scattering characteristics through fog are solved. Moreover, on the basis of scattering models, the depolarization ratio of broad-band polarized light is also measured. The physical models are demonstrated very consistent with the experimental results and Monte Carlo simulations. These works greatly simplify previous models and have a significant promotion to the study of medium scattering characteristics.

AM22, a novel synthetic microRNA, inhibits the proliferation of colorectal cancer cells by targeting core binding factor subunit ß (CBFB).

Our previous studies have revealed the important roles of the nonseed regions of microRNAs (miRNAs) in gene regulation, which provided novel insight into the development of miRNA analogs for cancer therapy. Here, we altered each nucleotide in the nonseed region of miR-34a and obtained novel synthetic miRNA analogs. Among them, AM22, with a base alteration from G to C at the 17th nucleotide of miR-34a, showed extensive antiproliferative activity against several colorectal tumor cell lines and achieved effective inhibition of core binding factor subunit ß (CBFB) expression. Subsequent investigations demonstrated that AM22 directly targeted CBFB by binding to its 3'-untranslated region (3'-UTR). Inhibition of CBFB showed obvious antiproliferative activity on HCT-116 and SW620 cells. Furthermore, the antiproliferative effects of AM22 on these cells were also measured in xenograft mouse models. In conclusion, this study identified AM22 as a potential antitumor miRNA by targeting CBFB and provided a new design approach for miRNA-based cancer treatment by changing the nonseed region of miRNA.

Antitumor activity of mianserin (a tetracyclic antidepressant) primarily driven by the inhibition of SLC1A5-mediated glutamine transport.

Targeting tumor metabolic vulnerabilities such as "glutamine addiction" has become an attractive approach for the discovery of novel antitumor agents. Among various mechanisms explored, SLC1A5, a membrane transporter that plays an important role in glutamine cellular uptake, represents a viable target to interfere with tumor's ability to acquire critical nutrients during proliferation. In the present study, a stably transfected HEK293 cell line with human SLC1A5 (HEK293-SLC1A5) was established for the screening and identification of small molecule SLC1A5 inhibitors. This in vitro system, in conjunction with direct measurement of SLC1A5-mediated L-glutamine-2,3,3,4,4-D5 (substrate) uptake, was practical and efficient in ensuring the specificity of SLC1A5 inhibition. Among a group of diverse compounds tested, mianserin (a tetracyclic antidepressant) demonstrated a marked inhibition of SLC1A5-mediated glutamine uptake. Subsequent investigations using SW480 cells demonstrated that mianserin was capable of inhibiting SW480 tumor growth both in vitro and in vivo, and the in vivo antitumor efficacy was correlated to the reduction of glutamine concentrations in tumor tissues. Computational analysis revealed that hydrophobic interactions between SLC1A5 and its inhibitors could be a critical factor in drug design. Taken together, the current findings confirmed the feasibility of targeting SLC1A5-mediated glutamine uptake as a novel approach for antitumor intervention. It is anticipated that structural insights obtained based on homology modeling would lead to the discovery of more potent and specific SLC1A5 inhibitors for clinical development.

Characterization of the metabolites of tirabrutinib generated from rat, dog and human liver microsomes using ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry.

RATIONALE: Tirabrutinib is an orally administered Bruton's tyrosine kinase (BTK) inhibitor developed for the treatment of autoimmune disorders and haematological malignancies. The goals of this study were to identify the metabolites of tirabrutinib and to propose the metabolic pathways. METHODS: Tirabrutinib was individually incubated with rat, dog and human liver microsomes at 37°C for 1 h. To trap the potential reactive metabolites, glutathione (GSH) was incorporated into the incubation samples. The incubation samples were analysed using ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry (UHPLC-HRMS). The metabolites were identified and characterized by exact masses, product ions and retention times. RESULTS: A total of 18 metabolites, including four GSH conjugates, were identified and characterized in terms of elemental compositions and product ions. The metabolic pathways of tirabrutinib included amide hydrolysis, O-dealkylation, mono-oxygenation, di-oxygenation and GSH conjugation. Among these metabolites, M10 was the most abundant metabolite. Compared with dog, rat has the closer metabolic profiles to humans, and thus it would be more suitable for toxicity study. CONCLUSIONS: This study provides valuable data regarding the in vitro metabolism of tirabrutinib, which may be helpful for further safety assessment of this drug.

Electrolyte Dynamics Engineering for Flexible Fiber-Shaped Aqueous Zinc-Ion Battery with Ultralong Stability.

Flexible aqueous zinc-ion batteries (ZIBs) are considered as promising energy storage devices for wearable electronics due to their cost-effectiveness, environmental friendliness, and high theoretical energy density. Herein, a flexible fiber-shaped aqueous ZIB is demonstrated by using a self-assembled Co3O4 nanosheet array on a carbon nanotube fiber as the cathode and Zn nanosheets deposited on a carbon nanotube fiber as the anode. The cycle life span of the fiber-shaped battery is largely enhanced by a simple electrolyte dynamics engineering strategy of preadding a trace amount of Co2+ cations in the mild aqueous electrolyte. The assembled fiber-shaped ZIB shows a high specific capacity (158.70 mAh g-1 at 1 A g-1), superior rate capacity, and excellent cycling life span (97.27% capacity retention after 10,000 cycles). Additionally, the fiber-shaped ZIB also shows superior flexibility, which can charge a smart watch under deformed states. This work provides new opportunities for the development of flexible, safe, and high-performance energy storage devices for wearable electronics.

Effect of rare coding variants of charged amino acid residues on the function of human organic anion transporting polypeptide 1B3 (SLCO1B3).

Human organic anion transporting polypeptide 1B3 (OATP1B3, gene symbol SLCO1B3) is a liver-specific uptake transporter. Its function was reported to be largely affected by some positively charged amino acid residues. However, so far the effect of naturally occurring genetic variants of charged residues on OATP1B3's function has not been explored yet. Therefore, in the present study nonsynonymous single nucleotide variants that led to the replacement of charged residues of OATP1B3 were investigated. Our results demonstrated that rare coding variants c.542G > A (p.R181H) and c.592G > A (p.D198N) had a great effect on the function of OATP1B3 mainly due to their influence on protein's surface expression. Further mutation studies showed that a negatively charged residue at position 198 was indispensable to the proper expression of OATP1B3 on the plasma membrane, while a positively charged reside at position 181 was not a must. Structural modeling indicated that R181 is located at the center of putative transmembrane domain 4 (TM4) and its side chain faces towards TM2 instead of towards the substrate translocation pathway, whereas D198 is located at the border of TM4 and intracellular loop 2 and may electrostatically repulse negatively charged phospholipid head groups. In conclusion, our results indicated that rare coding variants that cause changes of charged amino acid residues might have large influence on the function and expression of OATP1B3.

Concomitant inhibition of B7-H3 and PD-L1 expression by a novel and synthetic microRNA delivers potent antitumor activities in colorectal tumor models.

The families of miR-34 and miR-449 share the same seed region. However, the members showed differential effects on the expression of B7-H3 and PD-L1 in HCT-116 cells. Using miR-34a as a template, the non-seed region was modified by nucleotide alteration, yielding four synthetic microRNA (miRNA) analogs. Among those, NS-MX3, with a base alteration from G to C at the 18th locus of miR-34a, showed the most potent inhibition on both B7-H3 and PD-L1 expression. Subsequent investigations demonstrated that NS-MX3 had a broad anti-proliferation activity against several colorectal tumor cell lines and its antitumor effect was consistently reflected by tumor growth inhibition (TGI) in the HCT-116 xenograft model. In addition, NS-MX3 displayed a synergistic effect on TGI when combined with bevacizumab or regorafenib. Further analysis revealed that the superior antitumor activity of NS-MX3 was correlated to concomitant suppression of both B7-H3 and PD-L1 expression in tumor tissues. Taken together, the present study indicates that the non-seed region of miRNAs plays an important role in the regulation of checkpoint genes, thus showcasing single nucleotide alteration of the non-seed region as a promising approach to discover and develop novel immunotherapies.

The influencing factors of health-related quality of life among rural hypertensive individuals: a cross-sectional study.

BACKGROUND: Previous reports regarding health-related quality of life (HRQoL) of hypertensive individuals commonly concentrated on urban population. This study focused on rural population and aimed to explore the influencing factors of HRQoL. METHODS: Date were derived from Henan Rural Cohort study. The HRQoL of participants were assessed via European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L) instrument. Tobit regression model and generalized linear model were employed to explore the influencing factors of HRQoL. Another binary logistic regression was utilized to examine the robustness of our results. RESULTS: Among 23,485 rural population, 8128 participants were identified with hypertension. The mean (SD) utility index and VAS score of non-hypertension group were 0.96 (0.09) and 79.66 (14.20), respectively, while in hypertension group were 0.94 (0.14) and 75.88 (15.50), respectively. Pain/discomfort was the most common self-reported problem (23.05%) for patients. Aging and suffering with other diseases were negatively associated with HRQoL among rural patients, while high socioeconomic status and healthy lifestyles corresponded with high HRQoL. CONCLUSIONS: Hypertension did push considerable pressures on patients' HRQoL. Maintaining healthy lifestyles and improving the socioeconomic status of patients were advisable ways to reduce this burden. Trial registration The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). http://www.chictr.org.cn/showproj.aspx?proj=11375.

Developing a RadLex-Based Named Entity Recognition Tool for Mining Textual Radiology Reports: Development and Performance Evaluation Study.

BACKGROUND: Named entity recognition (NER) plays an important role in extracting the features of descriptions such as the name and location of a disease for mining free-text radiology reports. However, the performance of existing NER tools is limited because the number of entities that can be extracted depends on the dictionary lookup. In particular, the recognition of compound terms is very complicated because of the variety of patterns. OBJECTIVE: The aim of this study is to develop and evaluate an NER tool concerned with compound terms using RadLex for mining free-text radiology reports. METHODS: We leveraged the clinical Text Analysis and Knowledge Extraction System (cTAKES) to develop customized pipelines using both RadLex and SentiWordNet (a general purpose dictionary). We manually annotated 400 radiology reports for compound terms in noun phrases and used them as the gold standard for performance evaluation (precision, recall, and F-measure). In addition, we created a compound terms-enhanced dictionary (CtED) by analyzing false negatives and false positives and applied it to another 100 radiology reports for validation. We also evaluated the stem terms of compound terms by defining two measures: occurrence ratio (OR) and matching ratio (MR). RESULTS: The F-measure of cTAKES+RadLex+general purpose dictionary was 30.9% (precision 73.3% and recall 19.6%) and that of the combined CtED was 63.1% (precision 82.8% and recall 51%). The OR indicated that the stem terms of effusion, node, tube, and disease were used frequently, but it still lacks capturing compound terms. The MR showed that 71.85% (9411/13,098) of the stem terms matched with that of the ontologies, and RadLex improved approximately 22% of the MR from the cTAKES default dictionary. The OR and MR revealed that the characteristics of stem terms would have the potential to help generate synonymous phrases using the ontologies. CONCLUSIONS: We developed a RadLex-based customized pipeline for parsing radiology reports and demonstrated that CtED and stem term analysis has the potential to improve dictionary-based NER performance with regard to expanding vocabularies.

Metallic Sandwiched-Aerogel Hybrids Enabling Flexible and Stretchable Intelligent Sensor.

Flexible strain sensors have been widely investigated with their rapid development in human-machine interfaces, soft robots, and medical care monitoring. Here, we report a new in situ catalytic strategy toward the fabrication of metallic aerogel hybrids, which are composed of vanadium nitride (VN) nanosheets decorated with well-defined vertically aligned carbon nanotube arrays (VN/CNTs) for the first time. In this architecture, the two-dimensional VN nanosheets as the main bone structure are favorable for the flexible devices due to their excellent structural compatibility during the repetitive deforming process. In addition, the sandwiched aerogel hybrids form highly conductive 3D network, affording outstanding sensitivity for the strain-responsive behaviors. Further, the VN/CNTs-based flexible strain sensors are successfully fabricated, showing a high gauge factor of 386 within a small strain of 10%, fast response, and extraordinary durability. The monitoring of physical signals and an actual real-time human-machine controlling system based on the sensors are also presented.

Functional Characterization Reveals the Significance of Rare Coding Variations in Human Organic Anion Transporting Polypeptide 2B1 (SLCO2B1).

The organic anion transporting polypeptide 2B1 (OATP2B1), which is encoded by the SLCO2B1 gene, plays important roles in the absorption and disposition of its substrate drugs. Nonsynonymous variations of SLCO2B1 change its amino acid sequence and may alter its function. However, so far, very few genetic variants of SLCO2B1 have been functionally characterized. In the present study, first of all, 14 nonsynonymous single nucleotide variants (SNVs) of SLCO2B1 have been identified from the dbSNP database. Then, human embryonic kidney (HEK293) cells were employed as the expression system and functional studies were carried out for these 14 SNVs using substrates 4',5'-dibromofluorescein (DBF), estrone-3-sulfate (E3S), atorvastatin, and rosuvastatin. Our results showed that four nonsynonymous rare variants, namely, SLCO2B1 c.332G > A (p.R111Q), c.1184C > A (p.P395H), c.1624G > A (p.V542M), and c.1998C > A (p.F666L), have great effect on the function of OATP2B1. Surface biotinylation and immunoblot analysis indicated that the variant c.1184C > A (p.P395H) almost completely disrupted OATP2B1's expression on the plasma membrane. According to the three-dimensional structural model of OATP2B1 we developed, these four mutated residues are not located at the substrate binding region of OATP2B1. Their significant effect on the function of OATP2B1 could probably be attributed to jeopardizing OATP2B1's surface expression as exemplified by c.1184C > A (p.P395H), altering the transporter's overall structure and affecting its interactions with other proteins or the lipid bilayer. Taken together, our results demonstrated that rare coding variants could have a great impact on the function and expression of OATP2B1.