Fentanyl Initiated Polymers Prepared by ATRP for Targeted Delivery

Developing a 3-D computational model of neurons in the central amygdala to understand pharmacological targets for pain

Neuropathic and nociplastic pain are major causes of pain and involve brain areas such as the central nucleus of the amygdala (CeA). Within the CeA, neurons expressing protein kinase c-delta (PKCδ) or somatostatin (SST) have opposing roles in pain-like modulation. In this manuscript, we describe our progress towards developing a 3-D computational model of PKCδ and SST neurons in the CeA and the use of this model to explore the pharmacological targeting of these two neural populations in modulating nociception. Our 3-D model expands upon our existing 2-D computational framework by including a realistic 3-D spatial representation of the CeA and its subnuclei and a network of directed links that preserves morphological properties of PKCδ and SST neurons. The model consists of 13,000 neurons with cell-type specific properties and behaviors estimated from laboratory data. During each model time step, neuron firing rates are updated based on an external stimulus, inhibitory signals are transmitted between neurons via the network, and a measure of nociceptive output from the CeA is calculated as the difference in firing rates of pro-nociceptive PKCδ neurons and anti-nociceptive SST neurons. Model simulations were conducted to explore differences in output for three different spatial distributions of PKCδ and SST neurons. Our results show that the localization of these neuron populations within CeA subnuclei is a key parameter in identifying spatial and cell-type pharmacological targets for pain.

Recent Advances in the Application of ATRP in the Synthesis of Drug Delivery Systems

Advances in atom transfer radical polymerization (ATRP) have enabled the precise design and preparation of nanostructured polymeric materials for a variety of biomedical applications. This paper briefly summarizes recent developments in the synthesis of bio-therapeutics for drug delivery based on linear and branched block copolymers and bioconjugates using ATRP, which have been tested in drug delivery systems (DDSs) over the past decade. An important trend is the rapid development of a number of smart DDSs that can release bioactive materials in response to certain external stimuli, either physical (e.g., light, ultrasound, or temperature) or chemical factors (e.g., changes in pH values and/or environmental redox potential). The use of ATRPs in the synthesis of polymeric bioconjugates containing drugs, proteins, and nucleic acids, as well as systems applied in combination therapies, has also received considerable attention.

Application of vinyl polymer-based materials as nucleic acids carriers in cancer therapy

Nucleic acid-based therapies have changed the paradigm of cancer treatment, where conventional treatment modalities still have several limitations in terms of efficacy and severe side effects. However, these biomolecules have a short half-life in vivo, requiring multiple administrations, resulting in severe suffering, discomfort, and poor patient compliance. In the early days of (nano)biotechnology, these problems caused concern in the medical community, but recently it has been recognized that these challenges can be overcome by developing innovative formulations. This review focuses on the use of vinyl polymer-based materials for the protection and delivery of nucleic acids in cancer. First, an overview of the properties of nucleic acids and their versatility as drugs is provided. Then, key information on the achievements to date, the most effective delivery methods, and the evaluation of functionalization approaches (stimulatory strategies) are critically discussed to highlight the importance of vinyl polymers in the new cancer treatment approaches. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures.

Pharmaceutical technologies with potential application to insecticide discovery†

Novel neuroactive insecticides are discovered/registered differently, have a lower value in use, and exert their physiological actions in manners distinct from neuroactive pharmaceuticals, but there are clear similarities in their biochemical modes of action. Insecticides are generally discovered using whole pest insect screens, and this eases difficulties in 'translational science' from laboratory to field, as opposed to pharmaceutical translation from biochemical or cell-based targets to animal models to human clinical trials to registered drug. This paper examines recent trends in pharmaceutical science and identifies some technologies which may represent complementary approaches to insecticide discovery screening and mode of action determination beyond the sound processes in common practice today. Examples will be drawn from nanoparticle delivery of neuroactives, unique ligand-polymer conjugates, proposed advances in insect cell culture following from pharmaceutical cell biology, and laboratory or organ-on-a-chip approaches. It is hoped that these concepts will stimulate novel thinking which may enable discovery of efficacious new neuroactive insecticides. © 2020 Society of Chemical Industry.

Copper on chitosan-modified cellulose filter paper as an efficient dip catalyst for ATRP of MMA

Achieving an efficient catalyst in the ATRP system with a simple design, preparation from available materials, and high recyclability is a significant challenging issue. To attain the goal, herein, we used chitosan (CS)-modified cellulose filter paper (FP) as a green support for the synthesis of dip catalyst. The preparation of this catalyst involved surface treatment of the FP strips by CS coating through a dipping method, which increased the affinity of the substrate for adsorbing copper ions in the next step. The Cu@CS-FP catalyst was prepared without the requirement of any ligands. The synthesized dip-catalyst, in the form of the strips, was employed for the first time in the ATRP reaction of methyl methacrylate to assay catalytic activity. Catalytic insertion/ removal (ON/OFF) experiments were carried out during the polymerization. A reasonable control over the molecular weight with high conversion (68%) and polydispersity index of 1.32 under mild reaction conditions were obtained. Significantly, because of the facile separation of the catalyst, the amount of copper that remained in the polymer was very low (2.7 ppm). Also, the recyclability of the catalyst was investigated for five runs. The conversion in the final run was 64% without a loss of catalyst efficiency.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Hydroxyl-Rich PGMA-Based Cationic Glycopolymers for Intracellular siRNA Delivery: Biocompatibility and Effect of Sugar Decoration Degree

The ErbB family of proteins, structurally related to the epidermal growth factor receptor (EGFR), is found to be overexpressed in many cancers such as gliomas, a lung and cervical carcinomas. Gene therapy allows to modify the expression of genes like ErbB and has been a promising strategy to target oncogenes and tumor suppressor genes. In the current work, novel hydroxyl-rich poly(glycidyl methacrylate) (PGMA)-based cationic glycopolymers were designed for intracellular small interfering RNA (siRNA) delivery to silence the EGFR gene. The cationic polymers with different sugar decoration degrees (0, 9, and 33%) were synthesized by ring-opening reaction of PGMA with ethanolamine and a lactobionic acid-derived aminosaccharide (Lac-NH₂). Specific EGFR knockdown of the protein tyrosine kinase ErbB-overexpressing HeLa cells was achieved using these hydroxyl-rich polycation/siRNA complexes. Higher sugar content improved the biocompatibility of the polymers, but it also seems to decrease the EGFR knockdown capability, which should mainly be related to the surface charge of polyplexes. An optimum balance was observed with PGEL-1 (9% sugar content) formulation, achieving ∼52% knockdown efficiency as well as high cell viability. Considering the specific recognition between galactose residues and asialoglycoprotein receptor in hepatocytes, our novel PGMA-based cationic glycopolymers exhibited promising future to serve as a safe and targeting gene delivery vector to hepatoma cell line like HepG2.

Studies of the structure-antioxidant activity relationships and antioxidant activity mechanism of iridoid valepotriates and their degradation products

Oxidative stress has been associated with diverse diseases, including obesity, cancer and neurodegeneration. In fact, Valeriana jatamansi Jones (valerian) and its extracts possess strong antioxidant activities that extend their application in clinical practice to the treatment of these illnesses, even though the underlying mechanisms are not well understood. Iridoid valepotriate, a characteristic iridoid ester in valerian with poor chemical stability, possesses considerable antioxidant components. The original compounds and their degradation products have been found to exhibit strong antioxidant activities. However, the relationship between their structure and antioxidant effects and the mechanism underlying their oxidation resistance remain unclear. A forced degradation study using three iridoid valepotriates (valtrate, acevaltrate and 1-β acevaltrate) was performed in this work, and the structures of their degradation products were estimated by TLC-MS and LC-MS. Comparison of the antioxidant activities of the iridoid valepotriates before and after forced degradation revealed that degradation reduced the activities of the iridoid valepotriates in free radical scavenging and cytotoxic and cell apoptosis tests. The results suggested that the oxirane nucleus is important for defining the antioxidant profile of iridoid valepotriate. We uncovered possible mechanisms that could explain the antioxidant activities, including the generation of two hydroxyl groups through intramolecular transfer of an H• from an oxirane ring and a reduction in ROS levels through interactions with GABAergic signalling pathways.