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In vivo phage display screening to select peptide ligands targeting visceral adipose tissue via transdermal route. (A) A schematic diagram for in vivo transdermal phage display procedure in this study. (B) Total phage titer rescued from visceral adipose tissue after third round of phage display biopanning by dermal administration compared with the titer of wild-type M13 phage (**P < 0.01). (C) Accumulated peptide sequences versus distinct peptide sequences. The " accumulated peptide sequences " means total number of peptide sequences identified (total 280) from in vivo biopanning. Each identical peptide sequence appeared repeatedly during sequence identification was counted as one sequence in the " distinct peptide sequences. "
Source publication
To find novel peptide ligands targeting visceral adipose tissue (visceral fat) via transdermal route, in vivo phage display screening was conducted by dermal administration of a phage-peptide library to rats and a peptide sequence, CGLHPAFQC (designated as TDA1), was identified as a targeting ligand to visceral adipose tissue through the consecutiv...
Contexts in source publication
Context 1
... peptide-encoding DNA sequences were translated into amino acid sequences and their sequence similarities were analyzed by multisequence alignment using the Clustal X program (version 1.8) ( Thompson et al., 1997). Overall procedure of in vivo phage display in this study is depicted in Figure 1A. ...
Context 2
... recovered from the visceral adipose tissue at each round were quantified subsequently, and a total of 280 peptide sequences were determined from randomly selected individual phage recombinants that were rescued from the third round biopanning. As results, phage titer of the final third round was significantly higher than the control biopanning with wild-type M13 phage and it was inferred that peptide moi- eties that could specifically bind to visceral adipose tissue after skin penetration were enriched throughout the in vivo biopanning ( Figure 1B). In addition, as proceeding peptide sequence identification, a multiple alignment for identified peptide sequences revealed that some of iden- tical peptide sequences were appeared repeatedly (from twice to 28 times out of total 280 peptide sequences) from the third round-screened phage population and distinct peptide sequences were gradually decreased as identical peptide sequences increased ( Figure 1C). ...
Context 3
... results, phage titer of the final third round was significantly higher than the control biopanning with wild-type M13 phage and it was inferred that peptide moi- eties that could specifically bind to visceral adipose tissue after skin penetration were enriched throughout the in vivo biopanning ( Figure 1B). In addition, as proceeding peptide sequence identification, a multiple alignment for identified peptide sequences revealed that some of iden- tical peptide sequences were appeared repeatedly (from twice to 28 times out of total 280 peptide sequences) from the third round-screened phage population and distinct peptide sequences were gradually decreased as identical peptide sequences increased ( Figure 1C). This enrich- ment of converged sequences after iterative biopannings was generally considered as one of the primary evidences of targeted selection in phage display experiments (DiasNeto et al., 2009). ...
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Background
White adipose tissue can be classified based on its location as subcutaneous and visceral fat, and the latter accumulation is reported to be more detrimental to metabolism. Endoplasmic reticulum (ER) stress has been demonstrated to regulate lipogenesis. The peptide angiotensin(1–7) [Ang(1–7)], which can be produced from angiotensin II (A...
Citations
... Apart from PTP-decorated liposomal delivery system used in our study, aptamers specific to adipocytes have been selected for potential adipose-targeted delivery 55,56 . Adipocyte-targeting aptamer-modified gold nanoclusters, resveratrol-loaded liposomes, and Article https://doi.org/10.1038/s41467-022-35470-4 ...
Thyroid hormone (TH) is a thermogenic activator with anti-obesity potential. However, systemic TH administration has no obvious clinical benefits on weight reduction. Herein we selectively delivered triiodothyronine (T3) to adipose tissues by encapsulating T3 in liposomes modified with an adipose homing peptide (PLT3). Systemic T3 administration failed to promote thermogenesis in brown and white adipose tissues (WAT) due to a feedback suppression of sympathetic innervation. PLT3 therapy effectively obviated this feedback suppression on adrenergic inputs, and potently induced browning and thermogenesis of WAT, leading to alleviation of obesity, glucose intolerance, insulin resistance, and fatty liver in obese mice. Furthermore, PLT3 was much more effective than systemic T3 therapy in reducing hypercholesterolemia and atherosclerosis in apoE-deficient mice. These findings uncover WAT as a viable target mediating the therapeutic benefits of TH and provide a safe and efficient therapeutic strategy for obesity and its complications by delivering TH to adipose tissue.
... In contrast with this in vitro biopanning, the use of in vivo biopanning has major advantages as it allows selecting for specific binding of a biomolecules to a target tissue, while in parallel negatively selecting against all other tissues and cell types in the body. Indeed, using this in vivo approach novel peptides targeting murine BAT [365], WAT [368], and the adipose tissue endothelium [40], APCs [39,319,320] as well as adipocytes [33] were developed. Furthermore, targeting the adipose vasculature allowed the delivery of functional peptides and liposome into the adipose intercellular space [40,[369][370][371][372][373], suggesting that the surfome of the endothelium could also be a promising target in adipose tissue. ...
Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.
... [14][15][16][17][18][19][20][21][22][23][24] In other applications, therapeutic ligands [25][26][27][28] are made visible by a variety of imaging technologies in order to verify and quantify therapeutic interventions. As novel molecular theranostic ligands are designed for a wide range of both targets and routes of administration (e.g., intravenous injection, inhalation, intranasal delivery, etc.), [29][30][31][32][33][34][35][36] the ease-of-use and cost-effectiveness of conventional imaging systems will need to be improved to support these innovations. ...
Purpose
We investigated the feasibility of a novel positron emission tomography (PET) system that provides near real‐time feedback to an operator who can interactively scan a patient to optimize image quality. The system should be compact and mobile to support point‐of‐care (POC) molecular imaging applications. In this study, we present the key technologies required and discuss the potential benefits of such new capability.
Methods
The core of this novel PET technology includes trackable PET detectors and a fully three‐dimensional, fast image reconstruction engine implemented on multiple graphics processing units (GPUs) to support dynamically changing geometry by calculating the system matrix on‐the‐fly using a tube‐of‐response approach. With near real‐time image reconstruction capability, a POC‐PET system may comprise a maneuverable front PET detector and a second detector panel which can be stationary or moved synchronously with the front detector such that both panels face the region‐of‐interest (ROI) with the detector trajectory contoured around a patient's body. We built a proof‐of‐concept prototype using two planar detectors each consisting of a photomultiplier tube (PMT) optically coupled to an array of 48 × 48 lutetium‐yttrium oxyorthosilicate (LYSO) crystals (1.0 × 1.0 × 10.0 mm³ each). Only 38 × 38 crystals in each arrays can be clearly re‐solved and used for coincidence detection. One detector was mounted to a robotic arm which can position it at arbitrary locations, and the other detector was mounted on a rotational stage. A cylindrical phantom (102 mm in diameter, 150 mm long) with nine spherical lesions (8:1 tumor‐to‐background activity concentration ratio) was imaged from 27 sampling angles. List‐mode events were reconstructed to form images without or with time‐of‐flight (TOF) information. We conducted two Monte Carlo simulations using two POC‐PET systems. The first one uses the same phantom and detector setup as our experiment, with the detector coincidence re‐solving time (CRT) ranging from 100 to 700 ps full‐width‐at‐half‐maximum (FWHM). The second study simulates a body‐size phantom (316 × 228 × 160 mm³) imaged by a larger POC‐PET system that has 4 × 6 modules (32 × 32 LYSO crystals/module, four in axial and six in transaxial directions) in the front panel and 3 × 8 modules (16 × 16 LYSO crystals/module, three in axial and eight in transaxial directions) in the back panel. We also evaluated an interactive scanning strategy by progressively increasing the number of data sets used for image reconstruction. The updated images were analyzed based on the number of data sets and the detector CRT.
Results
The proof‐of‐concept prototype re‐solves most of the spherical lesions despite a limited number of coincidence events and incomplete sampling. TOF information reduces artifacts in the reconstructed images. Systems with better timing resolution exhibit improved image quality and reduced artifacts. We observed a reconstruction speed of 0.96 × 10⁶ events/s/iteration for 600 × 600 × 224 voxel rectilinear space using four GPUs. A POC‐PET system with significantly higher sensitivity can interactively image a body‐size object from four angles in less than 7 min.
Conclusions
We have developed GPU‐based fast image reconstruction capability to support a PET system with arbitrary and dynamically changing geometry. Using TOF PET detectors, we demonstrated the feasibility of a PET system that can provide timely visual feedback to an operator who can scan a patient interactively to support POC imaging applications.
... Cilengitide and Zafiride) ( Table 1). Moreover, these small peptide and nucleic acid agents can be designed for oral and transdermal delivery to increases dis- ease state accessibility and improve delivery outcomes [27][28][29][30]. Thus, biopanning methods for identifying a variety of targeting ligands are vital for developing and designing effective active targeting-carriers for a broad range of disease applications and administration routes. ...
... As intravenous administration of phage libraries resulted in rich identification of binding motifs within the vasculature, biopanning from alternative administration routes would be expected to provide access to alternative targets. Indeed, non-systemic administration of phage libraries has yielded targeting ligands for a wide variety of dis- eases [29,30,44,[74][75][76][77] (Table 4). Thus, the route of administration provides access to alternative targets that would normally be restricted by intravenous routes. ...
Targeting ligands are used in drug delivery to improve drug distribution to desired cells or tissues and to facilitate cellular entry. In vivo biopanning, whereby billions of potential ligand sequences are screened in biologically-relevant and complex conditions, is a powerful method for identification of novel target ligands. This tool has impacted drug delivery technologies and expanded our arsenal of therapeutics and diagnostics. Within this review we will discuss current in vivo panning technologies and ways that these technologies can be improved to advance next-generation drug delivery strategies.
... Damouche et al. [7 & ] demonstrate that HIV-1 DNA was detected in both CD4 þ T cells and sorted CD206 þ CD14 þ macrophages in adipose tissue samples from ARTtreated HIV-infected donors. A phage system that displays a visceral adipose tissue-specific peptide ligand (TDA1) has been developed by Lee et al. [30] which could form the homing moiety basis for a delivery system to target adipose macrophages. ...
Purpose of review:
A central question for the HIV cure field is to determine new ways to target clinically relevant, latently and actively replicating HIV-infected cells beyond resting memory CD4 T cells, particularly in anatomical areas of low drug penetrability.
Recent findings:
HIV eradication strategies being positioned for targeting HIV for extinction in the CD4 T-cell compartment may also show promise in non-CD4 T-cells reservoirs. Furthermore, several exciting novel therapeutic approaches specifically focused on HIV clearance from non-CD4 T-cell populations are being developed.
Summary:
Although reservoir validity in these non-CD4 T cells continues to remain debated, this review will highlight recent advances and make an argument as to their clinical relevancy as we progress towards an HIV cure.
... The target receptor of the peptide has been not identified; however, the interesting finding was that the peptide could recognize the vasculature not only in the classical BAT but also in the brown-like deposits in subcutaneous WAT that appeared in the cold-acclimated animals [60]. Peptides homing to adipose stromal cells, CSWKYWFGEC [61], and to mature adipocytes in visceral fat, CGLHPAFQC [62], were also found. The unique property of the adipocytehoming peptide is that the dermally administered peptide would first access the systemic circulation via hair follicles as its transdermal route and would then effectively target visceral fat [62]. ...
... Peptides homing to adipose stromal cells, CSWKYWFGEC [61], and to mature adipocytes in visceral fat, CGLHPAFQC [62], were also found. The unique property of the adipocytehoming peptide is that the dermally administered peptide would first access the systemic circulation via hair follicles as its transdermal route and would then effectively target visceral fat [62]. In addition to these peptides, it was also reported that the DNA aptamer, Adipo-8, exhibited a high affinity and specificity for differentiated adipocytes [63]. ...
... In order to avoid nonspecific recognition by RES, the surface of nanocarriers is frequently modified with PEG [92]. Moreover, Sadzuka et al. demonstrated that liposomes modified with a mixture of long and short PEG molecules showed an increased fixed aqueous layer thickness CPATAERPC Vascular endothelium of BAT Unknown [60] CGLHPAFQC Visceral adipose tissue, differentiated 3T3-L1 cell Unknown [62] CSWKYWFGEC Adipose stromal cells DDCN [61] DNA aptamer ATGAGAAGCGTCGGTGTGG TTAAACACGGAACGAAGGT GCAGGAAGATTTGTCGATG Differentiated 3T3-L1 cell, isolated mature adipocyte Unknown [63] Four types of peptides and one DNA aptamer are currently known to interact with the cells composed of WAT and BAT. BAT: Brown adipose tissue; DCN: Decorin; WAT: White adipose tissue. ...
Introduction:
Data reported during the last decade of the twentieth century indicate that passive targeting is an efficient strategy for delivering nanocarrier systems to tumor tissues. The focus of this review is on active targeting as a next-generation strategy for extending the capacity of a drug delivery system (DDS).
Areas covered:
Tumor vasculature targeting was achieved using arginine- glycine-aspartic acid, asparagine-glycine-arginine and other peptides, which are well-known peptides, as ligand against tumor vasculature. An efficient system for delivering small interfering RNA to the tumor vasculature involved the use of a multifunctional envelope-type nanodevice based on a pH-modified cationic lipid and targeting ligands. The active-targeting system was extended from tumor delivery to adipose tissue delivery, where endothelial cells are tightly linked and are impermeable to nanocarriers. In mice, prohibitin-targeted nanoparticles can be used to successfully deliver macromolecules to induce anti-obese effects. Finally, the successful delivery of nanocarriers to adipose tissue in obese mice via the enhanced permeability and retention-effect is reported, which can be achieved in tumor tissue.
Expert opinion:
Unlike tumor tissues, only a few reports have appeared on how liposomal carriers accumulate in adipose tissues after systemic injection. This finding, as well as active targeting to the adipose vasculature, promises to extend the capacity of DDS to adipose tissue. Since the site of action of nucleic acids is the cytosol, the intracellular trafficking of carriers and their cargoes as well as cellular uptake must be taken into consideration.
... Just as internal surface functionalisation of SBA-15 has been used to control the internal environment of SBA-15, external surface functionalisation is also used to directly address the extra-particle challenge of targeted delivery. This allows for the possibility of limiting therapeutic activity to specific areas and targets such as the blood--brain barrier [78,79], cancerous tissues [64,80], vasculature [81], adipose tissue [82,83], and so on, due to inherent physiological properties and local receptors. Pang et al. investigated the targeting of HeLa and A549 cancer cells mediated by the folic acid receptor [64]. ...
Introduction
Confinement of biomolecules in structured nanoporous materials offers several desirable features ranging from chemical and thermal stability, to resistance to degradation from the external environment. A new generation of mesoporous materials presents exciting new possibilities for the formulation and controlled release of biological agents. Such materials address niche applications in enteral and parenteral delivery of biologics, such as peptides, polypeptides, enzymes and proteins for use as therapeutics, imaging agents, biosensors, and adjuvants.
Areas covered
Mesoporous silica Santa Barbara Amorphous-15 (SBA-15), with its unique, tunable pore diameter, and easily functionalized surface, provides a representative example of this new generation of materials. Here, we review recent advances in the design and synthesis of nanostructured mesoporous materials, focusing on SBA-15, and highlight opportunities for the delivery of biological agents to various organ and tissue compartments.
Expert opinion
The SBA-15 platform provides a delivery carrier that is inherently separated from the active biologic due to distinct intra and extra-particle environments. This permits the SBA-15 platform to not require direct modification of the active biological therapeutic. Additionally, this makes the platform universal and allows for its application independent of the desired methods of discovery and development. The SBA-15 platform also directly addresses issues of targeted delivery and controlled release, although future challenges in the implementation of this platform reside in particle design, biocompatibility, and the tunability of the internal and external material properties. Examples illustrating the flexibility in the application of the SBA-15 platform are also discussed.
... CGLHPAFQC (TDA1 peptide) has been identified as a targeting ligand to visceral adipose tissue and this peptide could be potentially applied as a homing moiety for delivery of anti-obesity therapeutics to visceral fat through the convenient transdermal pathway [196]. Joint-homing peptides have been identified which can be further exploited for selective delivery of antiarthritic agents into the inflamed joints to enhance their efficacy while reducing systemic toxicity [197]. ...
Protein-protein interaction networks play a central role in a large number of cellular processes. Interaction networks are regulated to a large extent through post-translational modifications. The underlying causes of many diseases are found in defective protein-protein interactions and the resulting dysregulated signaling. Study and inhibition of protein-protein interaction networks are thus crucial to the understanding of physiological and disease processes. Small molecules so far have been the mainstay as chemical genetic and therapeutic tools. Inherent instability, low plasma half-life and other characteristics of peptides have so far prevented their widespread use in chemical genetics and therapy. However, recent developments have removed many of the drawbacks in use of peptides within cells and in organisms; as a consequence , peptides are poised to take a new leap as a promising class of molecules for use in chemical genetics and thera-peutics. In this article we review recent developments in this area. We discuss methods for developing peptides that bind a given target. We also explore the use of peptides for targeting to organs and organelles. Due to modular nature of func-tionalities within a peptide, different functionalities can be combined in a peptide with relative ease. This characteristic, combined with biocompatible nature of the entity make future of peptides bright as therapeutic agents.
... CGLHPAFQC (TDA1 peptide) has been identified as a targeting ligand to visceral adipose tissue and this peptide could be potentially applied as a homing moiety for delivery of anti-obesity therapeutics to visceral fat through the convenient transdermal pathway [196]. Joint-homing peptides have been identified which can be further exploited for selective delivery of antiarthritic agents into the inflamed joints to enhance their efficacy while reducing systemic toxicity [197]. ...
Protein-protein interaction networks play a central role in a large number of cellular processes. Interaction networks are regulated to a large extent through post-translational modifications. The underlying causes of many diseases are found in defective protein-protein interactions and the resulting dysregulated signaling. Study and inhibition of proteinprotein interaction networks are thus crucial to the understanding of physiological and disease processes. Small molecules so far have been the mainstay as chemical genetic and therapeutic tools. Inherent instability, low plasma half-life and other characteristics of peptides have so far prevented their widespread use in chemical genetics and therapy. However, recent developments have removed many of the drawbacks in use of peptides within cells and in organisms; as a consequence, peptides are poised to take a new leap as a promising class of molecules for use in chemical genetics and therapeutics. In this article we review recent developments in this area. We discuss methods for developing peptides that bind a given target. We also explore the use of peptides for targeting to organs and organelles. Due to modular nature of functionalities within a peptide, different functionalities can be combined in a peptide with relative ease. This characteristic, combined with biocompatible nature of the entity make future of peptides bright as therapeutic agents.
Phage display is a versatile method often used in the discovery of peptides that targets disease-related biomarkers. A major advantage of this technology is the ease and cost efficiency of affinity selection, also known as biopanning, to identify novel peptides. While it is relatively straightforward to identify peptides with optimal binding affinity, the pharmacokinetics of the selected peptides often prove to be suboptimal. Therefore, careful consideration of the experimental conditions, including the choice of using in vitro, in situ, or in vivo affinity selections, is essential in generating peptides with high affinity and specificity that also demonstrate desirable pharmacokinetics. Specifically, in vivo biopanning, or the combination of in vitro, in situ, and in vivo affinity selections, has been proven to influence the biodistribution and clearance of peptides and peptide-conjugated nanoparticles. Additionally, the marked difference in properties between peptides and nanoparticles must be considered. While peptide biodistribution depends primarily on physiochemical properties and can be modified by amino acid modifications, the size and shape of nanoparticles also affect both absorption and distribution. Thus, optimization of the desired pharmacokinetic properties should be an important consideration in biopanning strategies to enable the selection of peptides and peptide-conjugated nanoparticles that effectively target biomarkers in vivo.
