scholarly journals Evaluation of the Feasibility of Screening Tau Radiotracers Using an Amyloid Biomathematical Screening Methodology

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Ying-Hwey Nai ◽  
Hiroshi Watabe
Keyword(s):  
Time Window ◽  
Standardized Uptake Value ◽  
Clinical Usefulness ◽  
Reference Region ◽  
Time Activity ◽  
Default Time ◽  
Single Target ◽  
Comparison Results

The purpose of this study is to evaluate the feasibility of extending a previously developed amyloid biomathematical screening methodology to support the screening of tau radiotracers during compound development. 22 tau-related PET radiotracers were investigated. For each radiotracer, in silico MLogP, Vx, and in vitro KD were input into the model to predict the in vivo K1, k2, and BPND under healthy control (HC), mild cognitive impaired (MCI), and Alzheimer’s disease (AD) conditions. These kinetic parameters were used to simulate the time activity curves (TACs) in the target regions of HC, MCI, and AD and a reference region. Standardized uptake value ratios (SUVR) were determined from the integrated area under the TACs of the target region over the reference region within a default time window of 90–110 min. The predicted K1, k2, and BPND values were compared with the clinically observed values. The TACs and SUVR distributions were also simulated with population variations and noise. Finally, the clinical usefulness index (CUI) ranking was compared with clinical comparison results. The TACs and SUVR distributions differed for tau radiotracers with lower tau selectivity. The CUI values ranged from 0.0 to 16.2, with 6 out of 9 clinically applied tau radiotracers having CUI values higher than the recommend CUI value of 3.0. The differences between the clinically observed TACs and SUVR results showed that the evaluation of the clinical usefulness of tau radiotracer based on single target binding could not fully reflect in vivo tau binding. The screening methodology requires further study to improve the accuracy of screening tau radiotracers. However, the higher CUI rankings of clinically applied tau radiotracers with higher signal-to-noise ratio supported the use of the screening methodology in radiotracer development by allowing comparison of candidate radiotracers with clinically applied radiotracers based on SUVR, with respect to binding to a single target.

scholarly journals Guiding T lymphopoiesis from pluripotent stem cells by defined transcription factors

2019 ◽  
Author(s):  
Rongqun Guo ◽  
Fangxiao Hu ◽  
Qitong Weng ◽  
Cui Lv ◽  
Hongling Wu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Time Window ◽  
Immune Surveillance ◽  
Cell Stage ◽  
Immunodeficient Mice ◽  
Cell Transcriptome ◽  
T Lymphopoiesis

ABSTRACTAchievement of immunocompetent and therapeutic T lymphopoiesis from pluripotent stem cells is a central aim in T cell regenerative medicine. To date, preferentially regenerating T lymphopoiesis in vivo from pluripotent stem cells (PSC) remains a practical challenge. Here we documented that synergistic and transient expression of Runx1 and Hoxa9 restricted in the time window of endothelial to hematopoietic transition and hematopoietic maturation stages induced in vitro from PSC (iR9-PSC) preferentially generated engraftable hematopoietic progenitors capable of homing to thymus and developing into mature T (iT) cells in primary and secondary immunodeficient recipients. Single-cell transcriptome and functional analyses illustrated the cellular trajectory of T lineage induction from PSC, unveiling the T-lineage specification determined at as early as hemogenic endothelial cell stage and identifying the bona fide pre-thymic progenitors. The iT cells distributed normally in central and peripheral lymphoid organs and exhibited abundant TCRαβ repertoire. The regenerative T lymphopoiesis rescued the immune-surveillance ability in immunodeficient mice. Furthermore, gene-edited iR9-PSC produced tumor-specific-T cells in vivo that effectively eradicated tumor cells. This study provides insight into universal generation of functional and therapeutic T lymphopoiesis from the unlimited and editable PSC source.

scholarly journals In vitro and In vivo Assessment of Suitable Reference Region and Kinetic Modelling for the mGluR1 Radioligand [11C]ITDM in Mice

2019 ◽  
Vol 22 (4) ◽  
pp. 854-863 ◽  
Author(s):  
Daniele Bertoglio ◽  
Jeroen Verhaeghe ◽  
Špela Korat ◽  
Alan Miranda ◽  
Leonie wyffels ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Pet Imaging ◽  
Metabotropic Glutamate Receptor ◽  
Kinetic Modelling ◽  
Input Function ◽  
Dependent Manner ◽  
Reference Region ◽  
Suitable Reference

Abstract Purpose This study aimed at investigating binding specificity, suitability of reference region-based kinetic modelling, and pharmacokinetics of the metabotropic glutamate receptor 1 (mGluR1) radioligand [11C]ITDM in mice. Procedures We performed in vivo blocking as well as displacement of [11C]ITDM during positron emission tomography (PET) imaging using the specific mGluR1 antagonist YM-202074. Additionally, we assessed in vitro blocking of [3H]ITDM at two different doses of YM-202074. As an alternative to reference region models, we validated the use of a noninvasive image-derived input function (IDIF) compared to an arterial input function measured with an invasive arteriovenous (AV) shunt using a population-based curve for radiometabolite correction and characterized the pharmacokinetic modelling of [11C]ITDM in the mouse brain. Finally, we also assessed semi-quantitative approaches. Results In vivo blocking with YM-202074 resulted in a decreased [11C]ITDM binding, ranging from − 35.8 ± 8.0 % in pons to − 65.8 ± 3.0 % in thalamus. Displacement was also markedly observed in all tested regions. In addition, in vitro [3H]ITDM binding could be blocked in a dose-dependent manner. The volume of distribution (VT) based on the noninvasive IDIF (VT (IDIF)) showed excellent agreement with the VT values based on the metabolite-corrected plasma input function regardless of the metabolite correction (r2 > 0.943, p < 0.0001). Two-tissue compartmental model (2TCM) was found to be the preferred model and showed optimal agreement with Logan plot (r2 > 0.960, p < 0.0001). A minimum scan duration of 80 min was required for proper parameter estimation. SUV was not reliable (r2 = 0.379, p = 0.0011), unlike the SUV ratio to the SUV of the input function, which showed to be a valid approach. Conclusions No suitable reference region could be identified for [11C]ITDM as strongly supported by in vivo and in vitro evidence of specific binding in all brain regions. However, by applying appropriate kinetic models, [11C]ITDM PET imaging represents a promising tool to visualize mGluR1 in the mouse brain.

scholarly journals Engineered Fragments of the PSMA-Specific 5D3 Antibody and Their Functional Characterization

2020 ◽  
Vol 21 (18) ◽  
pp. 6672
Author(s):  
Zora Novakova ◽  
Nikola Belousova ◽  
Catherine A. Foss ◽  
Barbora Havlinova ◽  
Marketa Gresova ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Xenograft Model ◽  
In Vitro Assays ◽  
Experimental Therapy ◽  
Single Chain ◽  
Single Chain Fv ◽  
Murine Xenograft Model ◽  
Single Target

Prostate-Specific Membrane Antigen (PSMA) is an established biomarker for the imaging and experimental therapy of prostate cancer (PCa), as it is strongly upregulated in high-grade primary, androgen-independent, and metastatic lesions. Here, we report on the development and functional characterization of recombinant single-chain Fv (scFv) and Fab fragments derived from the 5D3 PSMA-specific monoclonal antibody (mAb). These fragments were engineered, heterologously expressed in insect S2 cells, and purified to homogeneity with yields up to 20 mg/L. In vitro assays including ELISA, immunofluorescence and flow cytometry, revealed that the fragments retain the nanomolar affinity and single target specificity of the parent 5D3 antibody. Importantly, using a murine xenograft model of PCa, we verified the suitability of fluorescently labeled fragments for in vivo imaging of PSMA-positive tumors and compared their pharmacokinetics and tissue distribution to the parent mAb. Collectively, our data provide an experimental basis for the further development of 5D3 recombinant fragments for future clinical use.

scholarly journals Simulating the effect of cerebral blood flow changes on regional quantification of [18F]flutemetamol and [18F]florbetaben studies

2020 ◽  
pp. 0271678X2091802
Author(s):  
Fiona Heeman ◽  
Maqsood Yaqub ◽  
Isadora Lopes Alves ◽  
Kerstin Heurling ◽  
Santiago Bullich ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Time Window ◽  
Standardized Uptake Value ◽  
Volume Of Distribution ◽  
Reference Tissue ◽  
Time Activity ◽  
Amyloid Load ◽  
Flow Changes ◽  
Simplified Reference Tissue Model

Global and regional changes in cerebral blood flow (CBF) can result in biased quantitative estimates of amyloid load by PET imaging. Therefore, the current simulation study assessed effects of these changes on amyloid quantification using a reference tissue approach for [18F]flutemetamol and [18F]florbetaben. Previously validated pharmacokinetic rate constants were used to simulate time-activity curves (TACs) corresponding to full dynamic and dual-time-window acquisition protocols. CBF changes were simulated by varying the tracer delivery ( K1) from +25 to −25%. The standardized uptake value ratio (SUVr) was computed and TACs were fitted using reference Logan (RLogan) and the simplified reference tissue model (SRTM) to obtain the relative delivery rate ( R1) and volume of distribution ratio (DVR). RLogan was least affected by CBF changes ( χ2 = 583 p <  0.001, χ2 = 81 p <  0.001, for [18F]flutemetamol and [18F]florbetaben, respectively) and the extent of CBF sensitivity generally increased for higher levels of amyloid. Further, SRTM-derived R1 changes correlated well with simulated CBF changes ( R2 > 0.95) and SUVr’s sensitivity to CBF changes improved for later uptake-times, with the exception of [18F]flutemetamol cortical changes. In conclusion, RLogan is the preferred method for amyloid quantification of [18F]flutemetamol and [18F]florbetaben studies and SRTM could be additionally used for obtaining a CBF proxy.

Integrating Network Pharmacology and Experimental Models to Investigate the Efficacy of Coptidis and Scutellaria Containing Huanglian Jiedu Decoction on Hepatocellular Carcinoma

2020 ◽  
Vol 48 (01) ◽  
pp. 161-182 ◽  
Author(s):  
Jihan Huang ◽  
Wei Guo ◽  
Fan Cheung ◽  
Hor-Yue Tan ◽  
Ning Wang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Mechanisms ◽  
Experimental Models ◽  
Network Pharmacology ◽  
Disease Networks ◽  
Cycle Arrest ◽  
Single Target ◽  
Induced Apoptosis

Unlike Western medicines with single-target, the traditional Chinese medicines (TCM) always exhibit diverse curative effects against multiple diseases through its “multi-components” and “multi-targets” manifestations. However, discovery and identification of the major therapeutic diseases and the underlying molecular mechanisms of TCM remain to be challenged. In the current study, we, for the first time, applied an integrated strategy by combining network pharmacology with experimental evaluation, for exploration and demonstration of the therapeutic potentials and the underlying possible mechanisms of a classic TCM formula, Huanglian Jiedu decoction (HLJDD). First, the herb–compound, compound–protein, protein–pathway, and gene–disease networks were constructed to predict the major therapeutic diseases of HLJDD and explore the underlying molecular mechanisms. Network pharmacology analysis showed the top one predicted disease of HLJDD treatment was cancer, especially hepatocellular carcinoma (HCC) and inflammation-related genes played an important role in the treatment of HLJDD on cancer. Next, based on the prediction by network pharmacology analysis, both in vitro HCC cell and in vivo orthotopic HCC implantation mouse models were established to validate the curative role of HLJDD. HLJDD exerted its antitumor activity on HCC in vitro, as demonstrated by impaired cell proliferation and colony formation abilities, induced apoptosis and cell cycle arrest, as well as inhibited migratory and invasive properties of HCC cells. The orthotopic HCC implantation mouse model further demonstrated the remarkable antitumour effects of HLJDD on HCC in vivo. In conclusion, our study demonstrated the effectiveness of integrating network pharmacology with experimental study for discovery and identification of the major therapeutic diseases and the underlying molecular mechanisms of TCM.

scholarly journals New Anti-Cancer Strategy to Suppress Colorectal Cancer Growth Through Inhibition of ATG4B and Lysosome Function

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1523 ◽  
Author(s):  
Yuanyuan Fu ◽  
Qianqian Gu ◽  
Li Luo ◽  
Jiecheng Xu ◽  
Yuping Luo ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Therapy ◽  
Therapeutic Strategy ◽  
Screening Method ◽  
Cancer Drug ◽  
Autophagic Flux ◽  
Single Target ◽  
Anti Cancer

Autophagy inhibition has been proposed to be a potential therapeutic strategy for cancer, however, few autophagy inhibitors have been developed. Recent studies have indicated that lysosome and autophagy related 4B cysteine peptidase (ATG4B) are two promising targets in autophagy for cancer therapy. Although some inhibitors of either lysosome or ATG4B were reported, there are limitations in the use of these single target compounds. Considering multi-functional drugs have advantages, such as high efficacy and low toxicity, we first screened and validated a batch of compounds designed and synthesized in our laboratory by combining the screening method of ATG4B inhibitors and the identification method of lysosome inhibitors. ATG4B activity was effectively inhibited in vitro. Moreover, 163N inhibited autophagic flux and caused the accumulation of autolysosomes. Further studies demonstrated that 163N could not affect the autophagosome-lysosome fusion but could cause lysosome dysfunction. In addition, 163N diminished tumor cell viability and impaired the development of colorectal cancer in vivo. The current study findings indicate that the dual effect inhibitor 163N offers an attractive new anti-cancer drug and compounds having a combination of lysosome inhibition and ATG4B inhibition are a promising therapeutic strategy for colorectal cancer therapy.

Therapeutic effects of 2B8T2M, a novel fusion of ALT-803, an IL-15 superagonist, with 4 single-chains of anti-CD20 antibody in combination with expanded natural killer cells against rituximab sensitive and resistant Burkitt lymphoma (BL).

2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 32-32
Author(s):  
Yaya Chu ◽  
Nang Kham Su ◽  
Sarah Alter ◽  
Emily Jeng ◽  
Peter R. Rhode ◽  
...  
Keyword(s):  
Nk Cells ◽  
Granzyme B ◽  
Treatment Options ◽  
Binding Activity ◽  
In Vitro Cytotoxicity ◽  
Patient Treatment ◽  
Therapeutic Effects ◽  
Comparison Results

32 Background: Patients retreated with rituximab often relapse which limit patient treatment options (Goldman/Cairo, Leukemia, 2013). Our group has successfully expanded functional and active peripheral blood NK cells (exPBNK) to target BL (Chu/Cairo, et al, Can Imm Res, 2015). 2B8T2M was generated by fusing ALT-803, an IL-15 superagonist, to four single-chains of rituximab (Liu/Wong, et al, JBC, 2016). 2B8T2M displayed tri-specific CD20 binding activity, activated NK cells to enhance antibody-dependent cellular cytotoxicity, and induced apoptosis of B-lymphoma cells (Liu/Wong, et al, JBC, 2016). Methods: ALT-803 and 2B8T2M were generously provided by Altor BioScience Corporation. NK expansion, NK receptors expression and cytotoxicity were examined as we previous described (Chu/Cairo, et al, Can Imm Res 2015). IFNg and granzyme B levels were examined by ELISA assays. Equal doses of IgG, Rituximab, ALT-803, Rituximab+ALT-803, obinutuzumab (obinu, generously provided by Christian Klein, PhD from Roche) were used for comparison. Results: 2B8T2M significantly enhanced exPBNK cytotoxicity against rituximab-sensitive Raji cells compared to the controls IgG, Rituximab, ALT-803, Rituximab+ALT-803, obinu (p < 0.001, E:T = 1:1). 2B8T2M also significantly enhanced exPBNK cytotoxicity against rituximab-resistant Raji-2R cells (p < 0.001, E:T = 1:1) and resistant Raji-4RH cells (p < 0.001, E:T = 1:1). Furthermore, 2B8T2M significantly enhanced IFN-g and granzyme B production from exPBNK against Raji, Raji-2R and Raji-4RH compared to IgG (p < 0.001), rituximab (p < 0.001), ALT-803 (p < 0.001), Rituximab+ALT-803 (p < 0.001), and obinutuzumab (p < 0.001). Conclusions: 2B8T2M compared to rituximab, ALT-803 or obinutuzumab significantly enhanced exPBNK in vitro cytotoxicity against rituximab-sensitive and –resistant BL cells. The in vivo functions of 2B8T2M with exPBNK using humanized NSG models are under investigation.

scholarly journals Freeze-frame imaging of synaptic activity using SynTagMA

2019 ◽  
Author(s):  
Alberto Perez-Alvarez ◽  
Brenna C. Fearey ◽  
Christian Schulze ◽  
Ryan J. O’Toole ◽  
Benjamien Moeyaert ◽  
...  
Keyword(s):  
High Throughput ◽  
Time Window ◽  
Large Datasets ◽  
Synaptic Activity ◽  
Analysis Program ◽  
Red Fluorescence ◽  
High Throughput Method ◽  
The Brain

ABSTRACTInformation within the brain travels from neuron to neuron across synapses. At any given moment, only a few synapses within billions will be active and are thought to transmit key information about the environment, a behavior being executed or memory being recalled. Here we present SynTagMA, which marks active synapses within a ~2 s time window. Upon violet illumination, the genetically expressed tag converts from green to red fluorescence if bound to calcium. Targeted to presynaptic terminals, preSynTagMA allows discrimination between active and silent axons. Targeted to excitatory postsynapses, postSynTagMA creates a snapshot of synapses active just before photoconversion. To analyze large datasets, we developed an analysis program that automatically identifies and tracks the fluorescence of thousands of individual synapses in tissue. Together, these tools provide a high throughput method for repeatedly mapping active synapses in vitro and in vivo.

scholarly journals Modeling of the Renal Kinetics of the AT1 Receptor Specific PET Radioligand [11C]KR31173

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Nedim C. M. Gulaldi ◽  
Jinsong Xia ◽  
Tao Feng ◽  
Kelvin Hong ◽  
William B. Mathews ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Compartmental Model ◽  
Radioligand Binding ◽  
Left Kidney ◽  
Binding Parameters ◽  
Retention Parameter ◽  
Time Activity ◽  
Kinetics Of

Purpose. The radioligand [11C]KR31173 has been introduced for PET imaging of the angiotensin II subtype 1 receptor (AT1R). The purpose of the present project was to employ and validate a compartmental model for quantification of the kinetics of this radioligand in a porcine model of renal ischemia followed by reperfusion (IR).Procedures. Ten domestic pigs were included in the study: five controls and five experimental animals with IR of the left kidney. To achieve IR, acute ischemia was created with a balloon inserted into the left renal artery and inflated for 60 minutes. Reperfusion was achieved by deflation and removal of the balloon. Blood chemistries, urine specific gravity and PH values, and circulating hormones of the renin angiotensin system were measured and PET imaging was performed one week after IR. Cortical time-activity curves obtained from a 90 min [11C]KR31173 dynamic PET study were processed with a compartmental model that included two tissue compartments connected in parallel. Radioligand binding quantified by radioligand retention (80 min value to maximum value ratio) was compared to the binding parameters derived from the compartmental model. A binding ratio was calculated asDVR=DVS/DVNS, whereDVSandDVNSrepresented the distribution volumes of specific binding and nonspecific binding. Receptor binding was also determined by autoradiographyin vitro.Results. Correlations between rate constants and binding parameters derived by the convolution and deconvolution curve fittings were significant(r>0.9). Also significant was the correlation between the retention parameter derived from the tissue activity curve (Yret) and the retention parameter derived from the impulse response function (fret). Furthermore, significant correlations were found between these two retention parameters and DVR. Measurements with PET showed no significant changes in the radioligand binding parameters caused by IR, and thesein vivofindings were confirmed by autoradiography performedin vitro.Conclusions. Correlations between various binding parameters support the concept of the parallel connectivity compartmental model. If an arterial input function cannot be obtained, simple radioligand retention may be adequate for estimation ofin vivoradioligand binding.

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