Platelet-derived Growth Factor B-chain Research Articles

A rhPDGF-BB/bovine type I collagen/β-TCP mixture for the treatment of critically sized non-union tibial defects: An in vivo study in rabbits.

Non-union during healing of bone fractures affects up to ~5% of patients worldwide. Given the success of recombinant human platelet-derived growth factor-B chain homodimer (rhPDGF-BB) in promoting angiogenesis and bone fusion in the hindfoot and ankle, rhPDGF-BB combined with bovine type I collagen/β-TCP matrix (AIBG) could serve as a viable alternative to autografts in the treatment of non-unions. Defects (~2 mm gaps) were surgically induced in tibiae of skeletally mature New Zealand white rabbits. Animals were allocated to one of four groups-(1) negative control (empty defect, healing for 8 weeks), (2 and 3) acute treatment with AIBG (healing for 4or 8weeks), and (4) chronic treatment with AIBG (injection 4 weeks post defect creation and then healing for 8 weeks). Bone formation was analyzed qualitatively and semi-quantitatively through histology. Samples were imaged using dual-energy X-ray absorptiometry and computed tomography for defect visualization and volumetric reconstruction, respectively. Delayed healing or non-healing was observed in the negative control group, whereas defects treated with AIBG in an acute setting yielded bone formation as early as 4 weeks with bone growth appearing discontinuous. At 8 weeks (acute setting), substantial remodeling was observed with higher degrees of bone organization characterized by appositional bone growth. The chronic healing, experimental, group yielded bone formation and remodeling, with no indication of non-union after treatment with AIBG. Furthermore, bone growth in the chronic healing group was accompanied by an increased presence of osteons, osteonal canals, and interstitial lamellae. Qualitatively and semiquantitatively, chronic application of AI facilitated complete bridging of the induced non-union defects, while untreated defects or defects treated acutely with AIBG demonstrated a lack of complete bridging at 8 weeks.

Characterization of toxicological effects of complex nano-sized metal particles using in vitro human cell and whole blood model systems.

Metal oxide fumes form at high temperatures, for instance, during welding or firing ammunition. Inhalation exposure to high levels of airborne metal oxide particles can cause metal fume fever, cardiovascular effects, and lung damage in humans, but the associated underlying pathological mechanisms are still not fully understood. Using human alveolar epithelial cells, vascular endothelial cells, and whole blood model systems, we aimed to elucidate the short-term effects of well-characterized metal particles emitted while firing pistol ammunition. Human lung epithelial cells exposed to gunshot smoke particles (0.1-50 μg/ml) produced reactive oxygen species (ROS) and pro-inflammatory cytokines (interleukin 8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF)) that activate and recruit immune cells. Particles comprising high copper (Cu) and zinc (Zn) content activated human endothelial cells via a non-ROS-mediated mechanism that triggered immune activation (IL-8, GM-CSF), leukocyte adhesion to the endothelium (soluble intercellular adhesion molecule 1 (sICAM-1)), and secretion of regulators of the acute-phase protein synthesis (interleukin 6 (IL-6)). In human whole blood, metal oxides in gunshot smoke demonstrated intrinsic properties that activated platelets (release of soluble cluster of differentiation 40 ligand (sCD40L), platelet-derived growth factor B-chain homodimer(PDGF-BB), and vascular endothelial growth factor A (VEGF-A)) and blood coagulation and induced concomitant release of pro-inflammatory cytokines from blood leukocytes that further orchestrate thrombogenesis. The model systems applied provide useful tools for health risk assessment of particle exposures, but more studies are needed to further elucidate the mechanisms of metal fume fever and to evaluate the potential risk of long-term cardiovascular diseases.

Design, synthesis and biological evaluation of novel trimethylangelicin analogues targeting nuclear factor kB (NF-kB)

A series of trimethylangelicin (TMA) derivatives were designed and synthesized to overcome the unwanted effects of TMA, promising agent for treatment of inflammation-related diseases and other pathologies, such as cystic fibrosis. The new generation TMA analogues bore hindered substituents at the 4 position in order to minimize or avoid the photoreactions with DNA. Among them, the 4-isopropyl-6-ethyl derivative 23 exhibited TMA-like inhibitory activity on NF-κB/DNA interactions but it proved unable to photoreact with pyrimidine bases of DNA, nor to induce any other DNA damage. The isopropyl analogue 23 was proven to lack mutagenicity when assayed through Ames test and exhibited no anti-proliferative activity on cystic fibrosis IB3-1 cells, displaying at the same time inhibition of the TNF-α induced release of the NF-κB regulated PDGF-B chain, IL-10, IL-15, IL-17 and IFN-γ. Therefore compound 23 deserves further assay to determine its anti-inflammatory properties, since it lacks photoreaction properties and mutagenicity-related side effects.

Dual-primer self-generation SERS signal amplification assay for PDGF-BB using label-free aptamer

Highly sensitive detection of proteins, especially those associated with cancers, is essential to biomedical research as well as clinical diagnosis. In this work, a simple and novel one-two-three signal amplification surface-enhanced Raman scattering (SERS) method for the detection of protein is fabricated by using label-free aptamer and dual-primer self-generation. Platelet-derived growth factor B-chain (PDGF-BB) is selected as the model protein. The one–two–three cascade DNA amplification means one target-aptamer binding event, two hairpin DNA switches and three DNA amplification reactions. This strategy possesses some remarkable features compared to conventional signal amplification methods: (i) A smart probe including a label-free aptamer is fabricated, for suitable hybridization without hindering the affinity of the aptamer toward its target. (ii) Using the unique structure switch of the aptamer and cooperator, a one–two–three working mode is developed to amplify the SERS signal. The amplification efficiency is enhanced. Given the unique and attractive characteristics, a simple and universal strategy is designed to accomplish ultrasensitive detection of proteins. The detection limit of PDGF-BB via SERS detection is 0.42pM, with the linear range from 1.0×10−12M to 10−8M. It is potentially universal because the aptamer can be easily designed for biomolecules whose aptamers undergo similar conformational changes.

Commentary: The unliganded glucocorticoid receptor positively regulates the tumor suppressor gene BRCA1 through GABP beta.

Commentary: The unliganded glucocorticoid receptor positively regulates the tumor suppressor gene BRCA1 through GABP beta.

Label-free nanopore proximity bioassay for platelet-derived growth factor detection.

Rapid and sensitive detection of biomarkers with ultralow concentrations remains a great challenge in disease diagnostics. Herein, we present a label-free α-hemolysin (α-HL) nanopore proximity bioassay for protein biomarker detection by a binding-induced DNA strand displacement strategy. In this bioassay, an individual target protein, platelet-derived growth factor B-chain (PDGF-BB), was selectively recognized by two oligonucleotide affinity ligands in which an output DNA was released and translocated through α-HL nanopore with a spikelike short current block. The frequency of the current block events had a linear relationship with the concentration of PDGF-BB with a wide linear dynamic range of 5 orders of magnitude and a detection limit at 500 fM. The selectivity and anti-interference capability of this bioassay show great potential for biomarker detection in bioanalytical chemistry.

R-spondin 1/dickkopf-1/beta-catenin machinery is involved in testicular embryonic angiogenesis.

Testicular vasculogenesis is one of the key processes regulating male gonad morphogenesis. The knowledge of the molecular cues underlining this phenomenon is one of today’s most challenging issues and could represent a major contribution toward a better understanding of the onset of testicular morphogenetic disorders. R-spondin 1 has been clearly established as a candidate for mammalian ovary determination. Conversely, very little information is available on the expression and role of R-spondin 1 during testicular morphogenesis. This study aims to clarify the distribution pattern of R-spondin 1 and other partners of its machinery during the entire period of testicular morphogenesis and to indicate the role of this system in testicular development. Our whole mount immunofluorescence results clearly demonstrate that R-spondin 1 is always detectable in the testicular coelomic partition, where testicular vasculature is organized, while Dickkopf-1 is never detectable in this area. Moreover, organ culture experiments of embryonic male UGRs demonstrated that Dickkopf-1 acted as an inhibitor of testis vasculature formation. Consistent with this observation, real-time PCR analyses demonstrated that DKK1 is able to slightly but significantly decrease the expression level of the endothelial marker Pecam1. The latter experiments allowed us to observe that DKK1 administration also perturbs the expression level of the Pdgf-b chain, which is consistent with some authors’ observations relating this factor with prenatal testicular patterning and angiogenesis. Interestingly, the DKK1 induced inhibition of testicular angiogenesis was rescued by the co-administration of R-spondin 1. In addition, R-spondin 1 alone was sufficient to enhance, in culture, testicular angiogenesis.

A label-free ultrasensitive electrochemical aptameric recognition system for protein assay based on hyperbranched rolling circle amplification

A label-free ultrasensitive electrochemical aptameric sensor which combined the advantages of an aptamer and hyperbranched rolling circle amplification (HRCA) has been developed for specific recognition of a platelet-derived growth factor B-chain (PDGF-BB).

Label-free and fluorescence turn-on aptasensor for protein detection via target-induced silver nanoclusters formation

A simple turn-on and homogeneous aptasensor, which relies on target induced formation of silver nanoclusters (Ag NCs), was developed for the determination of platelet-derived growth factor B-chain homodimer (PDGF-BB). The aptasensor contains two hairpin DNA probes termed as P1 and P2. P1 consists of the aptamer sequence of PDGF-BB. Meanwhile, P2 contains the Ag NCs nucleation sequence, which is blocked by the hairpin stem region. P1 and P2 can co-exist metastably in the absence of PDGF-BB and maintain hairpin structure. However, in the presence of PDGF-BB, the binding of PDGF-BB with aptamer will result in the hybridization between P1 and P2, and release the Ag NCs nucleation sequence. In this case, Ag NCs can be formed via the reduction of Ag+ by NaBH4. By monitoring the increase in fluorescence intensity, we could detect the target protein with high sensitivity. The detection limit of this aptasensor is 0.37nM, which is comparable with that of other reported aptasensors. Furthermore, this proposed aptasensor shows high selectivity toward its target protein. Thus, the proposed aptasensor based on target induced formation of Ag NCs could be used as a sensitive and selective platform for the detection of target protein.

Colorimetric and Ultrasensitive Bioassay Based on a Dual-Amplification System Using Aptamer and DNAzyme

Rapid detection of ultralow amount of biomarkers in a biologically complex mixture remains a major challenge. Herein, we report a novel aptamer-based protein detection assay that integrates two signal amplification processes, namely, polymerase-mediated rolling-circle amplification (RCA) and DNA enzyme-catalyzed colorimetric reaction. The target biomarker is captured in a sandwich assay by primary aptamer-functionalized microbeads (MBs) and a secondary aptamer that is connected to a RCA primer/circular template complex. RCA reaction, which amplifies the single biomarker binding events by a factor of hundreds to thousands (the first amplification) produces a long DNA molecule containing multiple DNAzyme units. The peroxidase-like DNAzyme catalyzes the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (the second amplification), which generates a blue-green colorimetric signal. This new biosensing platform permits the ultrasensitive, label-free, colorimetric detection of biomarker in real time. Using platelet-derived growth factor B-chain (PDGF-BB) as a model system, we demonstrated that our assay can detect a protein marker specifically in a serum-containing medium, at a concentration as low as 0.2 pg/mL in ∼2 h, which rivals traditional assays such as ELISA. We anticipate this simple methodology for biomarker detection can find utility in point-of-care applications.

Transcriptional regulation of platelet-derived growth factor-B chain by thrombin in endothelial cells: involvement of Egr-1 and CREB-binding protein

Thrombin and platelet-derived growth factor-B chain (PDGF-B) are key factors in the stimulation of atherosclerosis. The effect of thrombin on PDGF-B production has been characterized. However, the underlying mechanism is still far clear. Here, we investigate the transcription factors and regulators that are involved in PDGF-B production caused by thrombin in endothelial cells (ECs). Levels of PDGF were analyzed by real-time RT-PCR and ELISA, while levels of early growth response-1 (Egr-1) were analyzed by real-time RT-PCR and western blot. To evaluate the function of CBP and Egr-1 involved in regulation of PDGF-B, small interfering RNA (siRNA) were used to down-regulate their expression in mRNA and protein level. Interaction of Egr-1 and CBP was measured with immunoprecipitation and western blot. Thrombin induced an early and transient up-regulation of transcription factor early Egr-1, which was followed by a delayed increase of PDGF-B. siRNA against Egr-1-inhibited thrombin-induced PDGF-B production. Furthermore, thrombin could enhance the interaction of Egr-1 with its co-activator CREB-binding protein (CBP). CBP knockdown attenuated this interaction, and led to a reduction of PDGF-B expression induced by thrombin. Our results suggest that CBP might be one of the main interaction targets for Egr-1, and the transient activation of Egr-1 and recruitment of CBP are required for thrombin-induced PDGF-B in ECs.

Fluorescence Anisotropy Reduction of Allosteric Aptamer for Sensitive and Specific Protein Signaling

Real time protein signaling in a complex medium may provide a promising way for high-throughput protein analysis, but it is largely unmet due to the challenge of signal transduction and the interferences of nonspecific binding and high background. Our recent work indicates that a fluorescent aptamer can display a protein binding-induced reduction of fluorescence anisotropy (FA) (Zhang, D.; Lu, M.; Wang, H. J. Am. Chem. Soc. 2011, 133, 9188-9191), which is exclusively different from a traditionally simplified concept hinting a molecular size increase-induced FA increase. Inspired by this unexpected observation, we describe a novel FA reduction approach for protein signaling. The feasibility of this approach is demonstrated through the assays of a blood protein human α-thrombin and an oncoprotein human platelet-derived growth factor B-chain (PDGF-BB) using two screened fluorescent aptamers, respectively. By the developed FA reduction method, the spiked human α-thrombin in diluted serum can be detected at the concentration as low as 250 pM. In contrast, in a traditional molecular size-dependent FA assay, the thrombin spiked in diluted serum cannot induce reliable FA change even at a 256-fold higher concentration (64 nM). The results clearly show that the FA reduction approach has a dramatically enhanced specificity against target protein and high sensitivity in complex medium and is applicable to the no-separation based detection of proteins in biological matrixes.

Ultrasensitive aptamer-based bio bar code immunomagnetic separation and electrochemiluminescence method for the detection of protein

An ultrasensitive aptamer-based bio bar code immunomagnetic separation and electrochemiluminescence (IM-ECL) method for the detection of protein is developed. The target protein is captured by biotin-labeled aptamer (biotin probe) and [Ru(bpy)3]2+ (TBR)-Au bio bar code-labeled aptamer (ECL nanoprobe), to form a double aptamer–protein sandwich complex. The complex is then immobilized on the streptavidin microbeads through biotin–streptavidin linkage and detected by ECL assay. The ECL signal of the target protein is amplified by the TBR-bio bar code DNAs. As an example, platelet-derived growth factor B-chain homodimer (PDGF-BB) was detected by the method. Experimental results show that the detection limit of the assay is 1pM of PDGF-BB. A calibration curve with a linearity range from 1pM to 10nM is established, thus, make quantitative analysis possible. The method has been used to detect PDGF-BB in fetal calf serum with minimum background interference. Due to the wide availability of aptamer for numerous proteins, this aptamer-based bio bar code IM-ECL method holds great promise in protein detection.

Orbit-Infiltrating Mast Cells, Monocytes, and Macrophages Produce PDGF Isoforms that Orchestrate Orbital Fibroblast Activation in Graves' Ophthalmopathy

Platelet-derived growth factors (PDGF) are regulators of fibroblast activity that may be involved in the pathophysiology of Graves' ophthalmopathy (GO). We unraveled the expression and origin of PDGF family members in GO orbital tissue and investigated the effect of PDGF isoforms on IL-6 and hyaluronan production and proliferation by orbital fibroblasts. PDGF-A, PDGF-B, PDGF-C, PDGF-D, PDGF-Rα, and PDGF-Rβ expression was determined by real-time quantitative PCR and PDGF-A and PDGF-B protein expression was determined by Western blot in orbital tissues. Orbital tissues were immunohistochemically stained for PDGF-A and PDGF-B expression, together with stainings for T cells, monocytes, B cells, macrophages, and mast cells. Effects of PDGF-AA, PDGF-AB, and PDGF-BB on orbital fibroblast proliferation and IL-6 and hyaluronan production were examined. Finally, effects of PDGF-BB- and PDGF-AA-neutralizing antibodies on IL-6 and hyaluronan production in GO whole orbital tissue cultures were tested. GO orbital tissue showed increased PDGF-A and PDGF-B mRNA and protein levels. Increased numbers of PDGF-A- and PDGF-B-positive monocytes, macrophages, and mast cells were present in GO orbital tissue. PDGF-BB stimulated proliferation and hyaluronan and IL-6 production by orbital fibroblasts the most, followed by PDGF-AB and PDGF-AA. Finally, in particular imatinib mesylate and PDGF-BB-neutralizing antibodies reduced IL-6 and hyaluronan production by whole orbital tissue cultures from GO patients. In GO, mast cells, monocytes, and macrophages may activate orbital fibroblasts via secretion of especially PDGF-AB and PDGF-BB. Preclinical studies with whole orbital tissue cultures show that blocking PDGF-B chain containing isoforms can be a promising treatment for GO.

Hypoxia-inducible factor-1 α/platelet derived growth factor axis in HIV-associated pulmonary vascular remodeling

BackgroundHuman immunodeficiency virus (HIV) infected patients are at increased risk for the development of pulmonary arterial hypertension (PAH). Recent reports have demonstrated that HIV associated viral proteins induce reactive oxygen species (ROS) with resultant endothelial cell dysfunction and related vascular injury. In this study, we explored the impact of HIV protein induced oxidative stress on production of hypoxia inducible factor (HIF)-1α and platelet-derived growth factor (PDGF), critical mediators implicated in the pathogenesis of HIV-PAH.MethodsThe lungs from 4-5 months old HIV-1 transgenic (Tg) rats were assessed for the presence of pulmonary vascular remodeling and HIF-1α/PDGF-BB expression in comparison with wild type controls. Human primary pulmonary arterial endothelial cells (HPAEC) were treated with HIV-associated proteins in the presence or absence of pretreatment with antioxidants, for 24 hrs followed by estimation of ROS levels and western blot analysis of HIF-1α or PDGF-BB.ResultsHIV-Tg rats, a model with marked viral protein induced vascular oxidative stress in the absence of active HIV-1 replication demonstrated significant medial thickening of pulmonary vessels and increased right ventricular mass compared to wild-type controls, with increased expression of HIF-1α and PDGF-BB in HIV-Tg rats. The up-regulation of both HIF-1α and PDGF-B chain mRNA in each HIV-Tg rat was directly correlated with an increase in right ventricular/left ventricular+septum ratio. Supporting our in-vivo findings, HPAECs treated with HIV-proteins: Tat and gp120, demonstrated increased ROS and parallel increase of PDGF-BB expression with the maximum induction observed on treatment with R5 type gp-120CM. Pre-treatment of endothelial cells with antioxidants or transfection of cells with HIF-1α small interfering RNA resulted in abrogation of gp-120CM mediated induction of PDGF-BB, therefore, confirming that ROS generation and activation of HIF-1α plays critical role in gp120 mediated up-regulation of PDGF-BB.ConclusionIn summary, these findings indicate that viral protein induced oxidative stress results in HIF-1α dependent up-regulation of PDGF-BB and suggests the possible involvement of this pathway in the development of HIV-PAH.

Monocyte, macrophage and mast cell-derived PDGF control inflammation, tissue remodelling and autoimmunity in the pathophysiology of Graves’ ophthalmpathy

Methods Expression of PDGF family members was determined by RQ-PCR, Western Blot and immunohistochemistry in GO and control orbital tissue. The effect of PDGF-AA, PDGFAB and PDGF-BB was determined on OF proliferation, IL-6 production and hyaluronan production. Moreover, the effect of PDGF on TSHR expression by OF and their subsequent susceptibility for Graves’ Disease immunoglobulins (GD-IgG) was determined. Results PDGF-A and PDGF-B chains were increased in GO orbital tissue. Immunohistochemistry revealed that this was due to production by monocytes, macrophages and mast cells. PDGF induced proliferation, cytokine production and hyaluronan production by OF. Furthermore, PDGF increased TSHR expression on OF and enhanced their susceptibility to TSH and GD-IgG with regard to IL-6 and hyaluronan production. These effects of TSH and GD-IgG were inhibited by a cAMP inhibitor and by a TSHR blocking antibody, suggesting involvement of TSHR signaling. Remarkably, PDGF-BB has the most pronounced effect on OF, while PDGF-AA showed the least effect. Conclusion

Fluorescent Ferritin Nanoparticles and Application to the Aptamer Sensor

We synthesized fluorescent ferritin nanoparticles (FFNPs) through bacterial expression of the hybrid gene consisting of human ferritin heavy chain (hFTN-H), spacer (glycine-rich peptide), and enhanced green (or red) fluorescent protein [eGFP (or DsRed)] genes. The self-assembly activity of hFTN-H that leads to the formation of nanoparticles (12 nm in diameter), the conformational flexibility of the C-terminus of hFTN-H, and the glycine-rich spacer enabled eGFPs (or DsReds) to be well displayed on the surface of each ferritin nanoparticle, resulting in the construction of green (or red) FFNPs [gFFNPs (or rFFNPs)]. As compared to eGFP (or DsRed) alone, it is notable that the developed FFNPs showed significantly amplified fluorescence intensity and also enhanced stability. DNA aptamers were chemically conjugated to gFFNP via each eGFP's cysteine residue that was newly introduced through site-directed mutagenesis (Ser175Cys). The DNA-aptamer-conjugated gFFNPs were used as a fluorescent reporter probe in the aptamer-based "sandwich" assay of a cancer marker [i.e., platelet-derived growth factor B-chain homodimer (PDGF-BB)] in phosphate-buffered saline buffer or diluted human serum. This is a simple two-step assay without any additional steps for signal amplification, showing that compared to the same aptamer-based assays using eGFP alone or Cy3, the detection signals, affinity of the reporter probe to the cancer marker, and assay sensitivity were significantly enhanced; i.e., the limit of detection was lowered to the 100 fM level. Although the PDGF-BB assay is reported here as a proof-of-concept, the developed FFNPs can be applied in general to any aptamer-based sandwich assays.

HIV-1 Tat-Mediated Induction of Platelet-Derived Growth Factor in Astrocytes: Role of Early Growth Response Gene 1

HIV-associated neurologic disorders (HAND) are estimated to affect almost 60% of HIV-infected individuals. HIV encephalitis, the pathologic correlate of the most severe form of HAND, is often characterized by glial activation, cytokine-chemokine dysregulation, and neuronal damage and loss. However, the severity of HIV encephalitis correlates better with glial activation rather than viral load. Using the macaque model, it has been demonstrated that SIV encephalitis correlates with increased expression of the mitogen platelet-derived growth factor (PDGF) B chain in the brain. The goal of this study was to explore the role of PDGF-B chain in HIV-associated activation and proliferation of astrocytes. Specifically, the data demonstrate that exposure of rat and human astrocytes to the HIV-1 protein Tat resulted in the induction of PDGF at both the mRNA and protein levels. Furthermore, PDGF-BB induction was regulated by activation of ERK1/2 and JNK signaling pathways and the downstream transcription factor early growth response 1. Chromatin immunoprecipitation assays demonstrated binding of Egr-1 to the PDGF-B promoter. Exposure of astrocytes to PDGF-BB in turn led to increased proliferation and the release of proinflammatory cytokines MCP-1 and IL-1β. Because astrogliosis is linked to disease severity, understanding its regulation by PDGF-BB could aid in the development of therapeutic intervention strategies for HAND.

Anti‐PDGF‐B monoclonal antibody reduces liver fibrosis development

To evaluate the usefulness of a platelet-derived growth factor (PDGF)-B specific monoclonal antibody (mAb) as a therapeutic agent to treat chronic liver fibrosis. Liver fibrosis was induced in ICR mice by bile duct ligation (BDL) or BALB/c mice by weekly injection of concanavalin A (ConA) for 4 or 8 weeks. A mAb specific for mouse and human PDGF-B chain, AbyD3263, was generated, tested in vitro and administered twice a week throughout the experimental period. AbyD3263 showed neutralizing activity against mouse and human PDGF-B chain in cell-based assays, as measured in vitro by inhibition of phosphorylation of PDGF receptor β and proliferation of hepatic stellate cells induced by PDGF-BB. The half life of AbyD3263 in mice exceeded 7 days and dosing of animals twice a week resulted in constant plasma levels of the mAb. Induction of liver fibrosis by BDL and ConA resulted in elevated levels of alanine aminotransferase (ALT) in plasma and hydroxyproline in the liver. Treatment with AbyD3263 did not modify ALT levels, but significantly reduced hydroxyproline content in the liver with a maximum reduction of 39% and 54% in the BDL and ConA models, respectively, compared to controls. Conclusios: Consistent with the notion that PDGF-BB plays an important role in the progression of liver fibrosis, AbyD3263 exhibits efficacy in pre-clinical disease models suggesting that pharmacological inhibition of PDGF-B chain may be a therapeutic approach to treat liver fibrosis.

A new kind of aptamer-based immunomagnetic electrochemiluminescence assay for quantitative detection of protein

A new kind of aptamer-based immunomagnetic electrochemiluminescence (IM-ECL) assay for quantitative detection of protein is developed. The assay consists of a double aptamer sandwich format in which a biotin-labeled aptamer is used for rapid and specific capture of target protein, and a [Ru(bpy) 3] 2+ (TBR)-labeled aptamer is used for ECL detection. As an example, platelet-derived growth factor B-chain homodimer (PDGF-BB) was detected by the method. Experimental results show that the detection limit of the assay is 80 pmol/L of PDGF-BB. A calibration curve with a linearity range from 0.1 to 1000 nmol/L is established, thus, make quantitative analysis possible. The method has been used to detect PDGF-BB in fetal calf serum with minimum background interference. Due to the wide availability of aptamer for numerous proteins, this new method holds great promise in protein detection.