Acid Peptide Research Articles

The Tumorigenic Effect of lncRNA AFAP1-AS1 is Mediated by Translated Peptide ATMLP Under the Control of m6 A Methylation.

Long noncoding RNAs (lncRNAs) in eukaryotic transcripts have long been believed to regulate various aspects of cellular processes, including carcinogenesis. Herein, it is found that lncRNA AFAP1-AS1 encodes a conserved 90-amino acid peptide located on mitochondria, named lncRNA AFAP1-AS1 translated mitochondrial-localized peptide (ATMLP), and it is not the lncRNA but the peptide that promotes the malignancy of nonsmall cell lung cancer (NSCLC). As the tumor progresses, the serum level of ATMLP increases. NSCLC patients with high levels of ATMLP display poorer prognosis. Translation of ATMLP is controlled by m6 A methylation at the 1313 adenine locus of AFAP1-AS1. Mechanistically, ATMLP binds to the 4-nitrophenylphosphatase domain and non-neuronal SNAP25-like protein homolog 1 (NIPSNAP1) and inhibits its transport from the inner to the outer mitochondrial membrane, which antagonizes the NIPSNAP1-mediated regulation of cell autolysosome formation. The findings uncover a complex regulatory mechanism of NSCLC malignancy orchestrated by a peptide encoded by a lncRNA. A comprehensive judgment of the application prospects of ATMLP as an early diagnostic biomarker for NSCLC is also made.

Short Peptide Self-Assembly in the Martini Coarse-Grain Force Field Family.

ConspectusPivotal to the success of any computational experiment is the ability to make reliable predictions about the system under study and the time required to yield these results. Biomolecular interactions is one area of research that sits in every camp of resolution vs the time required, from the quantum mechanical level to in vivo studies. At an approximate midpoint, there is coarse-grained molecular dynamics, for which the Martini force fields have become the most widely used, fast enough to simulate the entire membrane of a mitochondrion though lacking atom-specific precision. While many force fields have been parametrized to account for a specific system under study, the Martini force field has aimed at casting a wider net with more generalized bead types that have demonstrated suitability for broad use and reuse in applications from protein-graphene oxide coassembly to polysaccharides interactions.In this Account, the progressive (Martini versions 1 through 3) and peripheral (Sour Martini, constant pH, Martini Straight, Dry Martini, etc.) developmental trajectory of the Martini force field will be analyzed in terms of self-assembling systems with a focus on short (two to three amino acids) peptide self-assembly in aqueous environments. In particular, this will focus on the effects of the Martini solvent model and compare how changes in bead definitions and mapping have effects on different systems. Considerable effort in the development of Martini has been expended to reduce the "stickiness" of amino acids to better simulate proteins in bilayers. We have included in this Account a short study of dipeptide self-assembly in water, using all mainstream Martini force fields, to examine their ability to reproduce this behavior. The three most recently released versions of Martini and variations in their solvents are used to simulate in triplicate all 400 dipeptides of the 20 gene-encoded amino acids. The ability of the force fields to model the self-assembly of the dipeptides in aqueoues environments is determined by the measurement of the aggregation propensity, and additional descriptors are used to gain further insight into the dipeptide aggregates.

Gene cloning, expression pattern, and response to dietary total lipids and phospholipids of hormone-sensitive lipase (HSL) in the Oriental river prawnMacrobrachium nipponenseDe Haan, 1849 (Decapoda: Caridea: Palaemonidae)

AbstractHormone-sensitive lipase (HSL) is an important regulator of cellular lipid homeostasis and catalyzes the hydrolysis of stored triacylglycerol. We identified and cloned for the first time the full-length cDNA sequence of HSL of the prawn Macrobrachium nipponense De Haan, 1849 [De Haan, 1833–1850] from a hepatopancreas cDNA library. The complete HSL sequence is 3,575 bp and encoded a 785 amino acid peptide with the catalytic core (GXSXG) containing a serine residue. The phylogenetic tree revealed that the gene of HSL of M. nipponense is closely related with that of Penaeus vanmameiBoone, 1931. The tissue distribution showed that the mRNA expression level of HSL in the hepatopancreas was significantly higher than that in other tissues (P < 0.05). Furthermore, the HSL expression in hepatopancreas was upregulated with the increase of dietary lipids but partially inhibited when the ratio of phospholipids was increased in the lipid mixture. These results demonstrate that HSL is involved in the lipid metabolism of M. nipponense and highlights the importance of phospholipids in lipid metabolism.

Abstract OT2-10-06: Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract Background: GP2 is a biologic nine amino acid peptide of the HER2/neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived and was followed for more than 6 months (p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events were observed considered related to the immunotherapy. Method: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Study Size – Interim Analysis: Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. Eligibility Criteria: The patient population is defined by these key eligibility criteria: 1. HER2/neu positive and HLA-A*02 2. Residual disease or High risk pCR (Stage III at presentation) post neo-adjuvant therapy 3. Exclude Stage IV 4. Completed at least 90% of planned trastuzumab-based therapy Trial Objectives: 1. To determine if GP2 therapy increases IBCFS 2. To assess the safety profile of GP2 3. To monitor immunologic responses to treatment and assess relationship to efficacy and safety Contact information: Snehal Patel Greenwich LifeSciences, Inc. Stafford, TX Email: snehal.patel@greenwichlifesciences.com Website: greenwichlifesciences.com Funding: This trial is supported by Greenwich LifeSciences. Citation Format: Snehal Patel, Jaye Thompson, Mira Patel, F. Joseph Daugherty, C. Kent Osborne, Mothaffar Rimawi. Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-10-06.

The usage of melittin in breast cancer microenvironment targeting

In today’s society, there are more people dying from breast cancer than ever. In fact, it has been projected that 1 in 39 women will die from breast cancer. Over the years, scientists have developed many forms of treatment to help alleviate some of the symptoms and keep the cancer at bay, such as chemotherapy and immunotherapy. Recently, however, a discovery has been made that could have the most efficacy and effectiveness against breast cancer. Melittin, a cationic peptide found in bee venom, is a 26 amino acid peptide that is being studied in many fields of medicine to be used as a new form of treatment in conjunction with the current forms. It is being tested in cancer research because of a special function that it has: the ability to start apoptosis by punching holes in the actual cell itself. In this paper, we will look at an overview of breast cancer’s history and statistics, look through some of the types of treatments that are already being used to fight breast cancer, and analyze five case studies to see how melittin can be used to target the microenvironments of breast cancer cells and figure out which method of treatment melittin will best fit into.

Immunomodulatory Role of Neuropeptide Y in Intestinal Inflammation

Neuropeptide Y (NPY) is a 36-amino acid peptide found in the brain, autonomic nervous system, and different peripheral tissues, including the gastrointestinal (GI) tract. Dysfunction of the NPY or NPY system has been implicated in various tumor microenvironments and cardiovascular and GI disorders, such as inflammatory bowel disease (IBD). IBD, including Crohn’s disease (CD) and ulcerative colitis (UC), is a major health concern due to its increasing incidence globally. Emerging evidence has demonstrated that NPY also acts as a potent immunomodulator by linking the nervous and immune systems. NPY plays an important role in immunopathology during intestinal inflammation. This paper discusses the potential role of NPY as a valuable biomarker for IBD due to its consistent upregulation in both in vivo and clinical studies. Consequently, it confirms the pro-inflammatory effects of NPY, providing a rational basis for targeting NPY signaling as a therapeutic strategy.

Integrating ultra-high-performance liquid chromatography tandem mass spectrometry and imaged capillary isoelectric focusing for in-depth characterization of complex fusion proteins.

Fc-fusion proteins represent a successful class of biopharmaceutical products, which combine the tailored pharmacological properties of biological ligands with the multiple functions of the fragment crystallizable domain of immunoglobulins. There is great diversity in terms of possible biological ligands creating highly diverse structures, therefore the analytical characterization of fusion proteins is far more complex than that of monoclonal antibodies and requires the use and development of additional product-specific methods over conventional generic/platform methods. Employing etanercept analogues as studied fusion proteins, the Orbitrap mass analyzer with ultra-high performance liquid chromatography (UHPLC-MS) and imaged capillary isoelectric focusing (icIEF) were utilized for the in-depth fusion protein characterization. The amino acid sequence coverage, peptide mapping, and post-translational modifications of etanercept analogues were analyzed by UHPLC-MS. The post-translational modification results were complemented by imaged capillary isoelectric focusing to produce quality research on etanercept analogues. The developed workflow integrating UHPLC-MS and icIEF provided an innovative strategy for characterizing complex fusion proteins in the process of quality control and manufacturing.

Allosteric effects of E. coli SSB and RecR proteins on RecO protein binding to DNA.

Escherichia coli single stranded (ss) DNA binding protein (SSB) plays essential roles in DNA maintenance. It binds ssDNA with high affinity through its N-terminal DNA binding core and recruits at least 17 different SSB interacting proteins (SIPs) that are involved in DNA replication, recombination, and repair via its nine amino acid acidic tip (SSB-Ct). E. coli RecO, a SIP, is an essential recombination mediator protein in the RecF pathway of DNA repair that binds ssDNA and forms a complex with E. coli RecR protein. Here, we report ssDNA binding studies of RecO and the effects of a 15 amino acid peptide containing the SSB-Ct monitored by light scattering, confocal microscope imaging, and analytical ultracentrifugation (AUC). We find that one RecO monomer can bind the oligodeoxythymidylate, (dT)15, while two RecO monomers can bind (dT)35 in the presence of the SSB-Ct peptide. When RecO is in molar excess over ssDNA, large RecO-ssDNA aggregates occur that form with higher propensity on ssDNA of increasing length. Binding of RecO to the SSB-Ct peptide inhibits RecO-ssDNA aggregation. RecOR complexes can bind ssDNA via RecO, but aggregation is suppressed even in the absence of the SSB-Ct peptide, demonstrating an allosteric effect of RecR on RecO binding to ssDNA. Under conditions where RecO binds ssDNA but does not form aggregates, SSB-Ct binding enhances the affinity of RecO for ssDNA. For RecOR complexes bound to ssDNA, we also observe a shift in RecOR complex equilibrium towards a RecR4O complex upon binding SSB-Ct. These results suggest a mechanism by which SSB recruits RecOR to facilitate loading of RecA onto ssDNA gaps.

Ghrelin and Obestatin Levels as a Novel Marker in Iraqi Obese Children

Obesity is an escalating health problem in developing countries. One to ten children worldwide are overweight in a report showed by the International Obesity Task Force. Ghrelin, orexigenic peptide, has 28 amino acids, it is considered the greatest remarkable promotion in the last two decades for understanding the physiological changes of action regu­lating food intake and hunger. Obestatin is a 23-amino acid peptide nearly connected to ghrelin that secures from substitution splicing the alike resort molecule, pre-proghrelin. The study is designed to assess the level of ghrelin and obestatin in Iraqi obese children and its relation with other biochemical parameters. Ghrelin and obeststin levels were measured in sixty obese children; the range of their age was (5-16) years, and this group was compared to 30 children in a healthy state as a control. Serum FBS, PPBS, and also lipid profiles (TG, TC, HDL-c, and LDL-c) were determined in the studied groups. Calculation of insulin resistance was done by using (HOMA-IR) a Homeostasis Model assessment of insulin resistance. Ghrelin levels were lower in a significant way in subjects who have obesity in comparison with control group. Significantly, there was a high increase in obestatin in obese patients when compared with control. This study demonstrates that obestatin raises and ghrelin is low in obesity, these hormones are related to the resistance of insulin, and there is an association between ghrelin and oxidative stress. The scales between obestatin and ghrelin are likely disturbed in obesity.

Dimeric Cholic Acid Peptide Conjugates Act as Effective Antibiotic Adjuvants against Multidrug Resistance (MDR) Gram‐Negative Bacterial Infections

AbstractMacrolides, glycopeptides, lipopeptides, and oxazolidinones class of antibiotics are used only for Gram‐positive bacteria, and are ineffective against Gram‐negative bacteria due to inability of these antibiotics to cross the Gram‐negative bacterial membranes. Here, dimeric cholic acid peptide conjugates as effective adjuvants that allow penetration of erythromycin across Gram‐negative bacteria are presented, making it effective antimicrobial. Here, it is shown that synthesized dimers2and3,having tetramethylene and pentamethylene spacers respectively between cholic acid‐triglycine conjugates, in combination with erythromycin cause synergistic antimicrobial effect against Gram‐negative bacteria. Biochemical studies reveal that dimer3causes outer and inner membrane permeabilization by interacting with lipopolysaccharide and displacing Mg2+ions, thereby allowing the erythromycin to cross bacterial membranes. Dimer3in combination with erythromycin can clear the preformed biofilms ofE. coliandP. aeruginosaeffectively. It is further demonstrated that combination of dimer3and erythromycin can clear wound infections ofE. coliandP. aeruginosa. Additionally, activities against multidrug resistant clinical strains ofE. coliandP. aeruginosawitness that combination of dimer3and erythromycin is an ideal combination to mitigate drug‐resistant infections.

Molecular Modeling of Self-Assembling Peptides.

Peptide epitopes mediate as many as 40% of protein-protein interactions and fulfill signaling, inhibition, and activation roles within the cell. Beyond protein recognition, some peptides can self- or coassemble into stable hydrogels, making them a readily available source of biomaterials. While these 3D assemblies are routinely characterized at the fiber level, there are missing atomistic details about the assembly scaffold. Such atomistic detail can be useful in the rational design of more stable scaffold structures and with improved accessibility to functional motifs. Computational approaches can in principle reduce the experimental cost of such an endeavor by predicting the assembly scaffold and identifying novel sequences that adopt said structure. Yet, inaccuracies in physical models and inefficient sampling have limited atomistic studies to short (two or three amino acid) peptides. Given recent developments in machine learning and advances in sampling strategies, we revisit the suitability of physical models for this task. We use the MELD (Modeling Employing Limited Data) approach to drive self-assembly in combination with generic data in cases where conventional MD is unsuccessful. Finally, despite recent developments in machine learning algorithms for protein structure and sequence predictions, we find the algorithms are not yet suited for studying the assembly of short peptides.

Antibodies to repeat-containing antigens in Plasmodium falciparum are exposure-dependent and short-lived in children in natural malaria infections.

Protection against Plasmodium falciparum, which is primarily antibody-mediated, requires recurrent exposure to develop. The study of both naturally acquired limited immunity and vaccine induced protection against malaria remains critical for ongoing eradication efforts. Towards this goal, we deployed a customized P. falciparum PhIP-seq T7 phage display library containing 238,068 tiled 62-amino acid peptides, covering all known coding regions, including antigenic variants, to systematically profile antibody targets in 198 Ugandan children and adults from high and moderate transmission settings. Repeat elements - short amino acid sequences repeated within a protein - were significantly enriched in antibody targets. While breadth of responses to repeat-containing peptides was twofold higher in children living in the high versus moderate exposure setting, no such differences were observed for peptides without repeats, suggesting that antibody responses to repeat-containing regions may be more exposure dependent and/or less durable in children than responses to regions without repeats. Additionally, short motifs associated with seroreactivity were extensively shared among hundreds of antigens, potentially representing cross-reactive epitopes. PfEMP1 shared motifs with the greatest number of other antigens, partly driven by the diversity of PfEMP1 sequences. These data suggest that the large number of repeat elements and potential cross-reactive epitopes found within antigenic regions of P. falciparum could contribute to the inefficient nature of malaria immunity.

D-amino acid peptides as antimicrobial agents against vibrio-associated diseases in aquaculture

Vibriosis is one of the most usual infection diseases in bivalve mollusks, particularly affecting seeds and larvae, which are more susceptible than adults to these bacterial infections. The devastating effect of vibriosis in shellfish hatcheries is aggravated by the increasing resistance of many Vibrio species to traditional antibiotics, highlighting the need to find new antimicrobial agents. Antimicrobial peptides (AMPs) are a promising alternative, however, their low stability can be a handicap for their practical application. In this study, the 3D structure and the stability of a synthetic all-D-amino acid peptide (D-Caerin) to proteases and extreme pH conditions have been analyzed and compared with its corresponding natural L-enantiomer peptide, Caerin 1.1. Moreover, the antimicrobial activity of D-Caerin has been tested in vitro against the control bacteria Micrococcus luteus CECT 245; and four Vibrio species: Vibrio aestuarianus CECT 625 T, Vibrio anguillarum CECT 522 T, Vibrio harveyi CECT 525 T and Vibrio tapetis CECT 4600 T, which are among the most representative causative agents of vibriosis in aquaculture. Our results demonstrate that D-Caerin contains two left-handed alpha helices, and is more stable and effective against the bacterial species tested than its corresponding natural L- counterpart. The bioactivity of D-Caerin has also been tested in vivo, in clam seeds infected with a mixed inoculum of these vibrio species. These preliminary assays show that D-Caerin-treated specimens exhibit higher survival rates after infection, demonstrating the superior stability of D-Caerin and its effectiveness against vibriosis-causative agents.

Peptide functionalized actively targeted MoS2 nanospheres for fluorescence imaging-guided controllable pH-responsive drug delivery and collaborative chemo/photodynamic therapy

The combination of imaging and different therapeutic strategies into one single nanoplatform often demonstrates improved efficacy over monotherapy in cancer treatments. Herein, a multifunctional nanoplatform (labelled as MPRD) based on molybdenum disulfide quantum dots (MoS2 QDs) is developed to achieve enhanced antitumor efficiency by integrating fluorescence imaging, tumor-targeting and synergistic chemo/photodynamic therapy (PDT) into one system. First, polyethylene glycol (PEG)ylated MoS2 QDs (MP) with desirable stability are synthesized via a hydrothermal process using MoS2 QDs and carboxyamino-terminated oligomeric PEG as raw materials. Then, MP were conjugated with arginine-glycine-aspartic acid (RGD) peptide via amidation to form a novel nanocarrier (MPR), which possesses strong blue fluorescence, good biocompatibility and ανβ3 receptor-mediated targeting ability. More importantly, MPR generated reactive oxygen species under 808 nm laser activation to realize targeted antitumor PDT. Further doxorubicin (DOX) was loaded onto MPR, which endows MPRD with localized chemotherapy and pH-responsive drug release. The MPRD exhibits improved chemotherapy performance on HepG2 cells (overexpressing integrin ανβ3) owing to enhanced cellular uptake mediated by ανβ3 receptor and effective drug release triggered by intracellular pH. Notably, MPRD with efficient tumor targeting ability and high chemo/PDT efficacy under NIR laser irradiation is capable of inhibiting HepG2 tumor cell growth both in vitro and in vivo, which is significantly superior to each individual therapy. These findings demonstrate that MPRD holds great potential in effective cancer therapy.

A novel and cost-effective method for high-throughput 3D culturing and rhythmic assessment of hiPSC-derived cardiomyocytes using retroreflective Janus microparticles

BackgroundHuman induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) gain attention as a potent cell source in regenerative medicine and drug discovery. With the necessity of the demands for experimental models to create a more physiologically relevant model of the heart in vitro we herein investigate a 3D culturing platform and a method for assessing rhythm in hiPSC-CMs.MethodsThe 3D cell culture PAMCELL™ plate is designed to enable cells to attach exclusively to adhesive patterned areas. These cell adhesive zones, named as micro-patterned pads, feature micron silica beads that are surface-modified with the well-known arginyl-glycyl-aspartic acid (RGD) peptide. RGD binding to the surface of hiPSC-CMs facilitates cell–cell attachment and the formation of uniform-size spheroids, which is controlled by the diameter of the micro-patterned pads. The assessment and evaluation of 3D hiPSC-CMs beating pattern are carried out using reflective properties of retroreflective Janus micro-particle (RJP). These RJPs are modified with an antibody targeting the gap junction protein found on the surface of hiPSC-CM spheroids. The signal assessment system comprises a camera attached to an optical microscope and a white light source.ResultsThe 3D PAMCELL™ R100 culture plate efficiently generate approximately 350 uniform-sized hiPSC-CM spheroids in each well of a 96-well plate and supported a 20-day culture. Analysis of genes and protein expression levels reveal that iPSC-CM spheroids grown on PAMCELL™ R100 retain cardiac stem cell characteristics and functions, outperforming traditional 2D culture platform. Additionally, the RJPs enable monitoring and evaluation of in vitro beating properties of cardiomyocytes without using complex monitoring setup. The system demonstrates its capability to identify alteration in the rhythmic activity of cardiac cells when exposed to ion channel blockers, nifedipine and E4031.ConclusionsThe integration of the 3D culture method and RJPs in this study establishes a platform for evaluating the rhythmic properties of 3D hiPSC-CMs. This approach holds significant potential for identifying arrhythmias or other cardiac abnormalities, ultimately contributing to the development of more effective therapies for heart diseases.Graphical

Core-Shell Magnetic Imprinted Polymers for the Recognition of FLAG-Tagpeptide

FLAG® tag (DYKDDDDK) is a small epitope peptide employed for the purification of recombinant proteins such as immunoglobulins, cytokines, and gene regulatory proteins. It provides superior purity and recoveries of fused target proteins when compared to the commonly used His-tag. Nevertheless, the immunoaffinity-based adsorbents required for their isolation are far more expensive than the ligand-based affinity resin used in combination with the His-tag. In order to overcome this limitation we report herein the development of molecularly imprinted polymers (MIPs) selective to the FLAG® tag. The polymers were prepared by the epitope imprinting approach using a four amino acids peptide, DYKD, including part of the FLAG® sequence as template molecule. Different kinds of magnetic polymers were synthesised in aqueous and organic media also using different sizes of magnetite core nanoparticles. The synthesised polymers were used as solid phase extraction materials with excellent recoveries and high specificity for both peptides. The magnetic properties of the polymers confer a new, effective, simple, and fast method in the purification using FLAG® tag.

Marine Natural Products from Flora and Fauna of the Western Australian Coast: Taxonomy, Isolation and Biological Activity.

Marine natural products occurring along the Western Australian coastline are the focus of this review. Western Australia covers one-third of the Australian coast, from tropical waters in the far north of the state to cooler temperate and Antarctic waters in the south. Over 40 years of research has resulted in the identification of a number of different types of secondary metabolites including terpenoids, alkaloids, polyketides, fatty acid derivatives, peptides and arsenic-containing natural products. Many of these compounds have been reported to display a variety of bioactivities. A description of the compound classes and their associated bioactivities from marine organisms found along the Western Australian coastline is presented.

Characteristics of Mitomycin C-Loaded Peptide Hydrogel In Vitro and Antiscarring Effects in Rat Ocular Injury Model.

Purpose: To investigate the characteristics of sustained drug release systems established by an arginine-glycine-aspartic acid (RGD) peptide hydrogel and mitomycin C (MMC) in vitro, and verify their antiscar effects in rat ocular injury model. Methods: Low, medium, and high loading doses of MMC were added to 5 mL 0.25%, 0.5%, and 1% wt RGD peptide hydrogel, respectively, to prepare 9 ratios of MMC-RGD systems. Drug release characteristics of the systems in phosphate-buffered saline solution were investigated by plotting the drug release curves and fitting them with mathematical models in OriginPro8.0 software. Appropriate ratios of MMC-RGD systems were selected as treatment in rat ocular injury model. Scar formation was observed by Masson staining and immunohistochemical staining with alpha-smooth muscle actin (α-SMA) and fibronectin (FN). Results: Nine ratios of MMC-RGD systems could release drug slowly. The maximum drug release proportions of all systems were >80%, and the time to maximum release proportions statistically prolonged with the increase of drug loading. Fitting with mathematical models indicated that the mechanisms of drug release were mainly Fick diffusion at early stage and Anomalous Transport at later stage. Systems of 1% wt RGD hydrogel were evaluated in animal experiments, which could inhibit hyperplasia of collagen and expression of α-SMA and FN. Conclusions: The RGD peptide hydrogel could be used as the carrier of MMC to establish sustained drug release system, which could inhibit scar formation after rat's ocular injury.

Polyhedral Oligomeric Silsesquioxane-Based Nanoparticles for Efficient Chemotherapy of Glioblastoma.

Glioblastoma (GBM) is the most common lethal brain tumor with dismal treatment outcomes and poor response to chemotherapy. As the regulatory center of cytogenetics and metabolism, most tumor chemotherapeutic molecules exert therapeutic effects in the nucleus. Nanodrugs showing the nuclear aggregation effect are expected to eliminate and fundamentally suppress tumor cells. In this study, a nanodrug delivery system based on polyhedral oligomeric silsesquioxane (POSS) is introduced to deliver drugs into the nuclei of GBM cells, effectively enhancing the therapeutic efficacy of chemotherapy. The nanoparticles are modified with folic acid and iRGD peptides molecules to improve their tumor cell targeting and uptake via receptor-mediated endocytosis. Nuclear aggregation allows for the direct delivery of chemotherapeutic drug temozolomide (TMZ) to the tumor cell nuclei, resulting in more significant DNA damage and inhibition of tumor cell proliferation. Herein, TMZ-loaded POSS nanoparticles can significantly improve the survival of GBM-bearing mice. Therefore, the modified POSS nanoparticles may serve as a promising drug-loaded delivery platform to improve chemotherapy outcomes in GBM patients.

Putative pore structure of amyloid beta and alpha synuclein in lipid bilayers.

Many degenerative diseases are characterized by aberrant protein aggregation. One possible mechanism of toxicity is the perturbation or permeabilization of cell membranes by certain types of oligomers. However, the structure of such membrane-inserted pore-forming complexes is unknown. Here we consider putative membrane-inserted β-barrels of Amyloid β and α-synuclein and evaluate them first in an implicit membrane model and then by multi-microsecond all atom simulation. The 11 amino acid peptide sequence of Aβ25-35 is relatively hydrophobic and readily embeds into synthetic bilayers producing ion channels. We consider octameric and decameric β barrels of different topology, strand orientation, and shear. Two decameric β barrels remain stably embedded in the membrane at the conclusion of these 5-μs all atom simulations: an antiparallel barrel with K28 in the pore lumen and a parallel barrel with the K28 in the membrane interface. Examination of the α-synuclein sequence reveals two regions that could form membrane-embedded β-hairpins: 35-56 and 64-92. We find that a 35-56 barrel remains inserted but dehydrates and collapses if all His50 are neutral. If half of the His50 are doubly protonated, however, the barrel takes an oval shape but remains hydrated and open. The 64-92 barrel remains hydrated for at least 10 µs. Our results for these pore structures may carry implications for familial Parkinson's mutations.