scholarly journals Lysosome Targeting Chimeras (LYTACs) That Engage a Liver-Specific Asialoglycoprotein Receptor for Targeted Protein Degradation

2020 ◽  
Author(s):  
Green Ahn ◽  
Steven Banik ◽  
Caitlyn L. Miller ◽  
Nicholas Riley ◽  
Jennifer R. Cochran ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Degradation ◽  
Pharmacokinetic Profile ◽  
Asialoglycoprotein Receptor ◽  
Surface Proteins ◽  
New Paradigm ◽  
Specific Chemical ◽  
Chemical Conjugation ◽  
Reduce Cell Proliferation

<p>Selective protein degradation platforms have afforded new development opportunities for therapeutics and tools for biological inquiry. The first lysosome targeting chimeras (LYTACs) targeted extracellular and membrane proteins for degradation by bridging a target protein to an endogenous lysosome targeting receptor, the cation-independent mannose-6-phosphate receptor (CI-M6PR). Here we developed LYTACs that engage the asialoglycoprotein receptor (ASGPR), a liver-specific lysosomal targeting receptor, to degrade membrane proteins in a tissue-specific manner. We conjugated antibody-based binders targeting cell-surface proteins to a tri-GalNAc motif that engages ASGPR. The resulting LYTACs directed lysosome trafficking of the bound targets and subsequent degradation. Degradation mediated by an EGFR-targeted GalNAc-LYTAC resulted in significant functional effects on the downstream kinase signaling of EGFR compared to canonical inhibition with a monoclonal antibody. Furthermore, we demonstrated that a small target binder, a 3.4 kDa peptide, can be linked to a single tri-GalNAc ligand to degrade integrins and significantly reduce cell proliferation. Site-specific chemical conjugation of one or two tri-GalNAc ligands to antibody scaffolds improved the pharmacokinetic profile of GalNAc-LYTACs <i>in vivo</i> compared to non-specific chemical conjugation. GalNAc-LYTACs represent an exciting new paradigm for cell-type restricted degradation of proteins.</p>

scholarly journals Lysosome Targeting Chimeras (LYTACs) That Engage a Liver-Specific Asialoglycoprotein Receptor for Targeted Protein Degradation

2020 ◽  
Author(s):  
Green Ahn ◽  
Steven Banik ◽  
Caitlyn L. Miller ◽  
Nicholas Riley ◽  
Jennifer R. Cochran ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Degradation ◽  
Pharmacokinetic Profile ◽  
Asialoglycoprotein Receptor ◽  
Surface Proteins ◽  
New Paradigm ◽  
Specific Chemical ◽  
Chemical Conjugation ◽  
Reduce Cell Proliferation

<p>Selective protein degradation platforms have afforded new development opportunities for therapeutics and tools for biological inquiry. The first lysosome targeting chimeras (LYTACs) targeted extracellular and membrane proteins for degradation by bridging a target protein to an endogenous lysosome targeting receptor, the cation-independent mannose-6-phosphate receptor (CI-M6PR). Here we developed LYTACs that engage the asialoglycoprotein receptor (ASGPR), a liver-specific lysosomal targeting receptor, to degrade membrane proteins in a tissue-specific manner. We conjugated antibody-based binders targeting cell-surface proteins to a tri-GalNAc motif that engages ASGPR. The resulting LYTACs directed lysosome trafficking of the bound targets and subsequent degradation. Degradation mediated by an EGFR-targeted GalNAc-LYTAC resulted in significant functional effects on the downstream kinase signaling of EGFR compared to canonical inhibition with a monoclonal antibody. Furthermore, we demonstrated that a small target binder, a 3.4 kDa peptide, can be linked to a single tri-GalNAc ligand to degrade integrins and significantly reduce cell proliferation. Site-specific chemical conjugation of one or two tri-GalNAc ligands to antibody scaffolds improved the pharmacokinetic profile of GalNAc-LYTACs <i>in vivo</i> compared to non-specific chemical conjugation. GalNAc-LYTACs represent an exciting new paradigm for cell-type restricted degradation of proteins.</p>

scholarly journals 635 A novel site-directed chemical conjugation technology confers antitumor activity via native Fc receptor to plasma immunoglobulin by attaching tumor binders

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A671-A671
Author(s):  
Christian Vidal ◽  
Michael Cukan ◽  
Rajat Varma ◽  
Lawrence Iben ◽  
Tanya Berbasova ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Chemical Engineering ◽  
Covalent Bond ◽  
Pharmacokinetic Profile ◽  
Release Mechanism ◽  
Chemical Reagents ◽  
Cell Counts ◽  
Chemical Conjugation

BackgroundWe describe KPMW101, which was created by chemical conjugation of a CD38-specific binder to clinical grade intravenous immunoglobulin (IvIg) pooled from healthy donors. Kleo’s MATETM technology enables efficient site-directed chemical conjugation to ‘off-the-shelf’ IvIg and allows the development of antitumor agents with rapidly introduced target specificity. Our platform allows for chemical engineering of existing IvIg in a cost-efficient manner. This technology relies on synthetic compounds that consists of antibody binder with react-and-release mechanism.MethodsDesign of synthetic chemical reagents included antibody binding group capable of covalent bond formation with specific lysine, CD38 binding moiety proven to work in our clinical candidate KP1237, and tunable non-cleavable linker. Conjugation efficiency to polyclonal IvIg was evaluated using LC-MS analysis of IdeZ-digests. The binding of CD38, CD16a, and FcRn were determined by ELISA and BLI.For in vitro ADCC assays, PBMCs provided NK effector function. Daudi (CD38+) B lymphoblast cells were treated with KPMW101 or IvIg, PBMCs were introduced and incubated for 18h, and target cellular death was measured. For an in vivo IP macrophage lavage model of ADCP, SCID mice were implanted IP with CFSE-labeled Daudi cells. Mice were injected with IvIg or KPMW101 (0.21, 0.625, 1.875 mg/kg) SQ, and tumor cell counts were measured by flow cytometry. The pharmacokinetic profile of in vivo KPMW101 was determined from blood and analyzed utilizing a human Ig isotyping array.ResultsSynthetic chemical reagents with multiple linker types have been conjugated to IvIg and evaluated in biochemical assays. KPMW101 showed the highest conjugation efficiency. Binding affinity of KPMW101 to CD38 was 27nM. ELISA results show KPMW101 binds to CD16a and FcRn, indicating that conjugation does not interfere with FcR binding.In vitro ADCC results demonstrate that KPMW101 elicited CD38+ target cell killing with an EC50 of 0.91–2.09nM.In vivo studies showed that KPMW101 resulted in a 49.9–63.5% reduction of tumor cells. Pharmacokinetic profile showed stability of KPMW101 throughout the 144-hour study, whereby IgG1, IgG2, IgG3, and IgG4 isotypes were detectable.ConclusionsKPMW101 is created by chemical conjugation of CD38-specific binder to IvIg using our proprietary MATETM technology, maintaining native binding to FcRs via the Fc domain. This ensures the stability of the molecule and retains immune-mediated mechanisms of action. KPMW101 induces IvIg to adopt Fc effector mechanisms like ADCC and ADCP. Our in vitro data and in vivo studies confirm KPMW101 ability to kill tumor cells, making IvIg into an active antitumor therapeutic agent.

scholarly journals Simultaneous Variation of the Immunodominant Outer Membrane Proteins, MSP2 and MSP3, during Anaplasma marginale Persistence In Vivo

2003 ◽  
Vol 71 (11) ◽  
pp. 6627-6632 ◽  
Author(s):  
Kelly A. Brayton ◽  
Patrick F. M. Meeus ◽  
Anthony F. Barbet ◽  
Guy H. Palmer
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Bacterial Pathogen ◽  
Anaplasma Marginale ◽  
Surface Proteins ◽  
Mammalian Host ◽  
Surface Coat ◽  
Vector Borne

ABSTRACT Vector-borne bacterial pathogens persist in the mammalian host by varying surface antigens to evade the existing immune response. To test whether the model of surface coat switching and immune evasion can be extended to a vector-borne bacterial pathogen with multiple immunodominant surface proteins, we examined Anaplasma marginale, a rickettsia with two highly immunogenic outer membrane proteins, major surface protein 2 (MSP2) and MSP3. The simultaneous clearance of variants of the two most immunodominant surface proteins of A. marginale followed by emergence of unique variants indicates that the switch rates and immune selection for MSP2 and MSP3 are sufficiently similar to explain the cyclic bacteremia observed during infection in the immunocompetent host.

Significance of In-Vitro and In-Vivo Correlation in Drug Delivery System

2018 ◽  
Vol 4 (4) ◽  
pp. 523-531
Author(s):  
Hina Mumtaz ◽  
Muhammad Asim Farooq ◽  
Zainab Batool ◽  
Anam Ahsan ◽  
Ashikujaman Syed
Keyword(s):  
Dosage Form ◽  
Pharmaceutical Preparations ◽  
Pharmacokinetic Profile ◽  
In Vitro Dissolution ◽  
Time Saving ◽  
Pharmaceutical Dosage Form ◽  
Short Period ◽  
Form Development

The main purpose of development pharmaceutical dosage form is to find out the in vivo and in vitro behavior of dosage form. This challenge is overcome by implementation of in-vivo and in-vitro correlation. Application of this technique is economical and time saving in dosage form development. It shortens the period of development dosage form as well as improves product quality. IVIVC reduce the experimental study on human because IVIVC involves the in vivo relevant media utilization in vitro specifications. The key goal of IVIVC is to serve as alternate for in vivo bioavailability studies and serve as justification for bio waivers. IVIVC follows the specifications and relevant quality control parameters that lead to improvement in pharmaceutical dosage form development in short period of time. Recently in-vivo in-vitro correlation (IVIVC) has found application to predict the pharmacokinetic behaviour of pharmaceutical preparations. It has emerged as a reliable tool to find the mode of absorption of several dosage forms. It is used to correlate the in-vitro dissolution with in vivo pharmacokinetic profile. IVIVC made use to predict the bioavailability of the drug of particular dosage form. IVIVC is satisfactory for the therapeutic release profile specifications of the formulation. IVIVC model has capability to predict plasma drug concentration from in vitro dissolution media.

Design, Synthesis, and Pharmacokinetic Evaluation of O-Carbamoyl Tizoxanide Prodrugs

2020 ◽  
Vol 16 ◽  
Author(s):  
Xi He ◽  
Wenjun Hu ◽  
Fanhua Meng ◽  
Xingzhou Li
Keyword(s):  
Plasma Concentration ◽  
Broad Spectrum ◽  
Plasma Concentrations ◽  
Antiviral Drug ◽  
Systemic Exposure ◽  
Pharmacokinetic Profile ◽  
Hydroxyl Group ◽  
First Pass

Background: The broad-spectrum antiparasitic drug nitazoxanide (N) has been repositioned as a broad-spectrum antiviral drug. Nitazoxanide’s in vivo antiviral activities are mainly attributed to its metabolitetizoxanide, the deacetylation product of nitazoxanide. In reference to the pharmacokinetic profile of nitazoxanide, we proposed the hypotheses that the low plasma concentrations and the low system exposure of tizoxanide after dosing with nitazoxanide result from significant first pass effects in the liver. It was thought that this may be due to the unstable acyloxy bond of nitazoxanide. Objective: Tizoxanide prodrugs, with the more stable formamyl substituent attached to the hydroxyl group rather than the acetyl group of nitazoxanide, were designed with the thought that they might be more stable in plasma. It was anticipated that these prodrugs might be less affected by the first pass effect, which would improve plasma concentrations and system exposure of tizoxanide. Method: These O-carbamoyl tizoxanide prodrugs were synthesized and evaluated in a mouse model for pharmacokinetic (PK) properties and in an in vitro model for plasma stabilities. Results: The results indicated that the plasma concentration and the systemic exposure of tizoxanide (T) after oral administration of O-carbamoyl tizoxanide prodrugs were much greater than that produced by equimolar dosage of nitazoxanide. It was also found that the plasma concentration and the systemic exposure of tizoxanide glucuronide (TG) were much lower than that produced by nitazoxanide. Conclusion: Further analysis showed that the suitable plasma stability of O-carbamoyl tizoxanide prodrugs is the key factor in maximizing the plasma concentration and the systemic exposure of the active ingredient tizoxanide.

A Comparative Pharmacokinetic Profile of Trahydropalmatine After Oral Administration of its Monomer, Rhizoma Corydalis Alkaloid Extracts and Tong-Bi-Si-Wei-Fang to Rats

2019 ◽  
Vol 15 (4) ◽  
pp. 338-345
Author(s):  
Lijun Ni ◽  
Lu Ding ◽  
Liguo Zhang ◽  
Shaorong Luan
Keyword(s):  
Oral Administration ◽  
Panax Notoginseng ◽  
Pharmacokinetic Profile ◽  
Apparent Volume ◽  
Bone Diseases ◽  
Glycyrrhiza Uralensis ◽  
Pharmacokinetic Property ◽  
Time Curve ◽  
Concentration Time

Background: Tong-Bi-Si-Wei-Fang (TBSWF) is a candidate formula of Traditional Chinese Medicine (TCM) for treating rheumatoid bone diseases, which is composed of rhizoma corydalis alkaloids, saponins of glycyrrhiza uralensis and panax notoginseng, flavonoids of rhizoma drynariae and glycyrrhiza uralensis. </P><P> Objective: Trahydropalmatine (THP), the main active ingredient of rhizoma corydalis alkaloids, was selected to study in vivo pharmacokinetics and druggability of TBSWF. Methods: The plasma concentration-time (C-T) profiles of THP and the pharmacokinetic property parameters after oral administration of THP monomer, extract of corydalis alkaloids (ECA) and TBSWF to rats, respectively were compared by a fully-validated HPLC method. Results: Compared to the THP monomer, the THP in TBSWF is absorbed faster, resides in the plasma longer and has a similar apparent volume of distribution Vz/F (10~20 L/kg). Compared to THP monomer and THP in TBSWF, the area under the concentration-time curve AUC 0-t of THP in ECA decreases two-third; Vz/F of THP in ECA (85.02 L/kg) is significantly higher than that of THP in TBSWF(p <0.05). Unlike THP monomer and THP in ECA, double peaks are observed in the C-T profile of THP after oral administration of TBSWF. THP in TBSWF exhibits slow release to a certain degree. Conclusion: The interactions among the ingredients of TBSWF promote the adsorption and prolong the residence time of THP in vivo, and provide an explanation for the advantages of TBSWF from the point of pharmacokinetics.

scholarly journals Breakdown of Filamentous Myofibrils by the UPS–Step by Step

Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Dina Aweida ◽  
Shenhav Cohen
Keyword(s):  
Protein Quality ◽  
Protein Structures ◽  
Ubiquitin Proteasome System ◽  
Surface Proteins ◽  
Catalytic Core ◽  
Complex Protein ◽  
Ubiquitin Proteasome ◽  
Aaa Atpases

Protein degradation maintains cellular integrity by regulating virtually all biological processes, whereas impaired proteolysis perturbs protein quality control, and often leads to human disease. Two major proteolytic systems are responsible for protein breakdown in all cells: autophagy, which facilitates the loss of organelles, protein aggregates, and cell surface proteins; and the ubiquitin-proteasome system (UPS), which promotes degradation of mainly soluble proteins. Recent findings indicate that more complex protein structures, such as filamentous assemblies, which are not accessible to the catalytic core of the proteasome in vitro, can be efficiently degraded by this proteolytic machinery in systemic catabolic states in vivo. Mechanisms that loosen the filamentous structure seem to be activated first, hence increasing the accessibility of protein constituents to the UPS. In this review, we will discuss the mechanisms underlying the disassembly and loss of the intricate insoluble filamentous myofibrils, which are responsible for muscle contraction, and whose degradation by the UPS causes weakness and disability in aging and disease. Several lines of evidence indicate that myofibril breakdown occurs in a strictly ordered and controlled manner, and the function of AAA-ATPases is crucial for their disassembly and loss.

scholarly journals Lipoproteins Are Responsible for the Pro-Inflammatory Property of Staphylococcus aureus Extracellular Vesicles

2021 ◽  
Vol 22 (13) ◽  
pp. 7099
Author(s):  
Pradeep Kumar Kopparapu ◽  
Meghshree Deshmukh ◽  
Zhicheng Hu ◽  
Majd Mohammad ◽  
Marco Maugeri ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Inflammatory Responses ◽  
Surface Proteins ◽  
Host Cells ◽  
Immune Stimulation ◽  
Domains Of Life ◽  
Major Surface ◽  
Staphylococcal Aureus

Staphylococcal aureus (S. aureus), a Gram-positive bacteria, is known to cause various infections. Extracellular vesicles (EVs) are a heterogeneous array of membranous structures secreted by cells from all three domains of life, i.e., eukaryotes, bacteria, and archaea. Bacterial EVs are implied to be involved in both bacteria–bacteria and bacteria–host interactions during infections. It is still unclear how S. aureus EVs interact with host cells and induce inflammatory responses. In this study, EVs were isolated from S. aureus and mutant strains deficient in either prelipoprotein lipidation (Δlgt) or major surface proteins (ΔsrtAB). Their immunostimulatory capacities were assessed both in vitro and in vivo. We found that S. aureus EVs induced pro-inflammatory responses both in vitro and in vivo. However, this activity was dependent on lipidated lipoproteins (Lpp), since EVs isolated from the Δlgt showed no stimulation. On the other hand, EVs isolated from the ΔsrtAB mutant showed full immune stimulation, indicating the cell wall anchoring of surface proteins did not play a role in immune stimulation. The immune stimulation of S. aureus EVs was mediated mainly by monocytes/macrophages and was TLR2 dependent. In this study, we demonstrated that not only free Lpp but also EV-imbedded Lpp had high pro-inflammatory activity.

scholarly journals High-Performance Liquid Chromatography-Tandem Mass Spectrometry for Buprenorphine Evaluation in Plasma—Application to Pharmacokinetic Studies in Rabbits

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 437
Author(s):  
Marta Tikhomirov ◽  
Błażej Poźniak ◽  
Tomasz Śniegocki
Keyword(s):  
High Performance ◽  
Pharmacokinetic Profile ◽  
Pharmacokinetic Studies ◽  
Limit Of Quantification ◽  
Reliable Determination ◽  
Main Challenge ◽  
Analytical Protocol ◽  
Liquid Chromatography Tandem Mass ◽  
Cost Efficient

The precise and reliable determination of buprenorphine concentration is fundamental in certain medical or research applications, particularly in pharmacokinetic studies of this opioid. The main challenge is, however, the development of an analytical method that is sensitive enough, as the detected in vivo concentrations often fall in very low ranges. Thus, in this study we aimed at developing a sensitive, repeatable, cost-efficient, and easy HPLC analytical protocol for buprenorphine in rabbit plasma. In order to obtain this, the HPLC-MS2 system was used to elaborate and validate the method for samples purified with liquid-liquid extraction. Fragment ions 468.6→396.2 and 468.6→414.2 were monitored, and the method resulted in a high repeatability and reproducibility and a limit of quantification of 0.25 µg/L with a recovery of 98.7–109.0%. The method was linear in a range of 0.25–2000 µg/L. The suitability of the analytical procedure was tested in rabbits in a pilot pharmacokinetic study, and it was revealed that the method was suitable for comprehensively describing the pharmacokinetic profile after buprenorphine intravenous administration at a dose of 300 µg/kg. Thus, the method suitability for pharmacokinetic application was confirmed by both the good validation results of the method and successful in vivo tests in rabbits.

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