Colin W Pouton

Colin W Pouton
Monash University (Australia) · Monash Institute of Pharmaceutical Sciences

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274
Publications
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Publications

Publications (274)
Article
Full-text available
We investigated mRNA vaccines encoding a membrane-anchored receptor-binding domain (RBD), each a fusion of a variant RBD, the transmembrane (TM) and cytoplasmic tail fragments of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. In naive mice, RBD-TM mRNA vaccines against SARS-CoV-2 variants induced strong humoral resp...
Article
Existing antibodies (Abs) have varied effects on humoral immunity during subsequent infections. Here, we leveraged in vivo systems that allow precise control of antigen-specific Abs and B cells to examine the impact of Ab dose, affinity, and specificity in directing B cell activation and differentiation. Abs competing with the B cell receptor (BCR)...
Preprint
Efficient and precise delivery of mRNA is critical to advance mRNA therapies beyond their current use as vaccines. Lipid nanoparticles (LNP) efficiently encapsulate and protect mRNA, but non-specific cellular uptake may lead to off-target delivery and minimal delivery to target cells. Functionalizing LNPs with antibodies enables targeted mRNA deliv...
Preprint
Full-text available
Mycobacterium tuberculosis remains the largest infectious cause of mortality worldwide, even with over a century of widespread administration of the only licensed tuberculosis (TB) vaccine, Bacillus Calmette-Guerin (BCG). mRNA technology remains an underexplored approach for combating chronic bacterial infections such as TB. We have developed a lip...
Article
Full-text available
The development of lipid nanoparticles (LNP) holds great promise for vaccine and therapeutic applications. However, ineffective transport of nucleic acid cargo from endosomes to the cytosol, termed “endosomal escape,” has remained a bottleneck to achieving greater LNP efficacy. Poor understanding of the mechanisms of endosomal escape and a lack of...
Article
Full-text available
Background SARS-CoV-2 booster vaccination needs to enhance protection against variants and minimise immune imprinting. The beta variant drove broad immunity against other SARS-CoV-2 variants, including omicron. We developed 2 vaccines targeting the beta variant receptor-binding domain (RBD): a recombinant dimeric RBD-human IgG1Fc -fusion protein, a...
Article
Background SARS-CoV-2 booster vaccination should ideally enhance protection against variants and minimise immune imprinting. This Phase I trial evaluated two vaccines targeting SARS-CoV-2 beta-variant receptor-binding domain (RBD): a recombinant dimeric RBD-human IgG1 Fc-fusion protein, and an mRNA encoding a membrane-anchored RBD. Methods 76 heal...
Preprint
Full-text available
To address the limitations of whole-spike COVID vaccines, we explored mRNA vaccines encoding membrane-anchored receptor-binding domain (RBD-TMs), each a fusion of a variant RBD, the transmembrane (TM) and cytoplasmic tail (CT) fragments of the SARS-CoV-2 spike protein. In naive mice, RBD-TM mRNA vaccines against ancestral SARS-CoV-2, Beta, Delta, D...
Article
Full-text available
Lipid nanoparticles (LNPs) are the prime delivery vehicle for mRNA vaccines. Previous hypotheses suggested that LNPs contribute to innate reactogenicity and lead to the establishment of a vaccine adaptive response. It has not been clear whether LNP adjuvancy in the muscle is the prime driver of adaptive immune responses or whether delivery to secon...
Article
Lipid-based formulation (LBF) is an effective approach for delivering hydrophobic drugs into the systemic circulation by oral administration. However, much of the physical detail regarding the colloidal behavior of LBFs and their interactions with the contents of the gastrointestinal (GI) environment is not well characterized. Recently, researchers...
Article
While a range of strategies exist to accomplish peptide macrocyclization, they are frequently limited by the need for orthogonal protection or provide little opportunity for structural diversification. We have evaluated an efficient macrocyclization method that employs nucleophilic aromatic substitution (SNAr) to create thioether macrocycles. This...
Article
Full-text available
The generation of midbrain dopaminergic neurons (mDAs) from pluripotent stem cells (hPSC) holds much promise for both disease modelling studies and as a cell therapy for Parkinson’s disease (PD). Generally, dopaminergic neuron differentiation paradigms rely on inhibition of smad signalling for neural induction followed by hedgehog signalling and an...
Article
Despite intensive long-term efforts, with very few exceptions, the development of effective vaccines against parasitic infections has presented considerable challenges, given the complexity of parasite life cycles, the interplay between parasites and their hosts, and their capacity to escape the host immune system and to regulate host immune respon...
Article
Full-text available
Changes in sub-cellular pH play a key role in metabolism, membrane transport, and triggering cargo release from therapeutic delivery systems. Most methods to measure pH rely on intensity changes of pH sensitive fluorophores, however, these measurements are hampered by high uncertainty in the inferred pH and the need for multiple fluorophores. To ad...
Preprint
Full-text available
The SARS-CoV-2 global pandemic has fuelled the generation of vaccines at an unprecedented pace and scale. However, many challenges remain, including: the emergence of vaccine-resistant mutant viruses, vaccine stability during storage and transport, waning vaccine-induced immunity, and concerns about infrequent adverse events associated with existin...
Article
Full-text available
Rod-shaped nanoparticles have been identified as promising drug delivery candidates. In this report, the in vitro cell uptake and in vivo pharmacokinetic/bio-distribution behavior of molecular bottle-brush (BB) and cyclic peptide self-assembled nanotubes were studied in the size range of 36-41 nm in length. It was found that BB possessed the longes...
Article
Full-text available
Ionizable cationic lipids play a critical role in developing new gene therapies for various biomedical applications, including COVID-19 vaccines. However, it remains unclear whether the formulation of lipid nanoparticles (LNPs) using DLin-MC3-DMA, an optimized ionizable lipid clinically used for small interfering RNA (siRNA) therapy, also facilitat...
Preprint
Changes in sub-cellular pH play a key role in metabolism, cell growth, membrane transport, and can also be exploited to control cargo release from therapeutic delivery systems. Most methods to measure pH rely on intensity changes of pH sensitive fluorophores, however these measurements are hampered by high uncertainty in the inferred pH and the nee...
Article
Full-text available
In this study we investigate how β-catenin-dependent WNT signalling impacts midbrain dopaminergic neuron (mDA) specification. mDA cultures at day 65 of differentiation responded to 25 days of the tankyrase inhibitor XAV969 (XAV, 100nM) with reduced expression of markers of an A9 mDA phenotype (KCNJ6, ALDH1A1 and TH) but increased expression of the...
Article
Full-text available
Objective Molecular dynamics (MD) simulations provide an in silico method to study the structure of lipid-based formulations (LBFs) and the incorporation of poorly water-soluble drugs within such formulations. In order to validate the ability of MD to effectively model the properties of LBFs, this work investigates the well-known cyclosporine A for...
Article
Full-text available
Cytosolic transport is an essential requirement but a major obstacle to efficient delivery of therapeutic peptides, proteins and nucleic acids. Current understanding of cytosolic delivery mechanisms remains limited due to a significant number of conflicting reports, which are compounded by low sensitivity and indirect assays. To resolve this, we de...
Article
Full-text available
PurposeSuccessful oral peptide delivery faces two major hurdles: low enzymatic stability in the gastro-intestinal lumen and poor intestinal membrane permeability. While lipid-based formulations (LBF) have the potential to overcome these barriers, effective formulation of peptides remains challenging. Lipophilic salt (LS) technology can increase the...
Article
Full-text available
Vaccination represents the best line of defense against infectious diseases and is crucial in curtailing pandemic spread of emerging pathogens to which a population has limited immunity. In recent years, mRNA vaccines have been proposed as the new frontier in vaccination, owing to their facile and rapid development while providing a safer alternati...
Article
Full-text available
The role of microglia cells in Alzheimer’s disease (AD) is well recognized, however their molecular and functional diversity remain unclear. Here, we isolated amyloid plaque-containing (using labelling with methoxy-XO4, XO4⁺) and non-containing (XO4⁻) microglia from an AD mouse model. Transcriptomics analysis identified different transcriptional tr...
Article
Full-text available
Adenoviruses contain dsDNA covalently linked to a terminal protein (TP) at the 5′end. TP plays a pivotal role in replication and long-lasting infectivity. TP has been reported to contain a nuclear localisation signal (NLS) that facilitates its import into the nucleus. We studied the potential NLS motifs within TP using molecular and cellular biolog...
Article
Drug absorption from lipid-based formulations (LBFs) in the gastrointestinal (GI) tract is the result of a series of processes, including formulation dispersion, interaction with biliary and pancreatic secretions, drug solubilisation and supersaturation, and finally intestinal permeability. Optimal formulation design is dependent on a good understa...
Article
Inhibitors of protein-protein interactions can be developed through a number of technologies to provide leads that include cell-impermeable molecules. Redesign of these impermeable leads to provide cell-permeable derivatives can be challenging and costly. We hypothesised that intracellular toxicity of leads could be assessed by microinjection prior...
Article
Hypothesis Non-ionic surfactants containing polyethylene oxide (PEO) chains are widely used in drug formulations, cosmetics, paints, textiles and detergents. High quality molecular dynamics models for PEO surfactants can give us detailed, atomic-scale information about the behavior of surfactant/water mixtures. Simulations We used two molecular dy...
Preprint
Full-text available
Endosomal escape is an essential requirement but a major obstacle to efficient delivery of therapeutic peptides, proteins and nucleic acids. Current understanding of endosomal escape mechanisms remains limited due to significant number of conflicting reports, which are compounded by low sensitivity and indirect assays. To resolve this, we developed...
Article
Polylactide-co-glycolide (PLGA) nanoparticles are one of the most commonly explored biodegradable polymeric drug carriers for inhaled delivery. Despite their advantages as inhalable nanomedicine scaffolds, we still lack a complete understanding of the kinetics and major pathways by which these materials are cleared from the lungs. This information...
Research
Full-text available
Gene therapy using non-viral gene delivery vehicle might be applied for the treatment of viral infection, cancer and genetic disorders. However, the most challenging barrier is the low efficiency of transgene expression. Therefore, optimization of transgene expression is very important and critical to be performed before doing extensive evaluation...
Article
Full-text available
Multiple protocols have been published for generation of iMGLs from hESCs/iPSCs. To date, there are no guides to assist researchers to determine the most appropriate methodology for microglial studies. To establish a framework to facilitate future microglial studies, we first performed a comparative transcriptional analysis between iMGLs derived us...
Article
Dopaminergic neurons (DAns), generated from human pluripotent stem cells (hPSCs), are capable of functionally integrating following transplantation and have recently advanced to clinical trials for Parkinson's disease (PD). However, pre-clinical studies have highlighted the low proportion of DAns within hPSC-derived grafts and their inferior plasti...
Preprint
The derivation of neurotransmitter and region-specific neuronal populations from human pluripotent stem cells (PSC) provides impetus for advancing cell therapies into the clinic. At the forefront is our ability to generate ventral midbrain (VM) dopaminergic (DA) progenitors, suitable for transplantation in Parkinsons disease (PD). Pre-clinical stud...
Article
Full-text available
Human pluripotent stem cells (hPSC) are a promising resource for the replacement of degenerated ventral midbrain dopaminergic (vmDA) neurons in Parkinson's disease. Despite recent advances in protocols for the in vitro generation of vmDA neurons, the asynchronous and heterogeneous nature of the differentiations results in transplants of surprisingl...
Preprint
Full-text available
The important role of microglia, the brain's resident immune cells, in Alzheimer's disease (AD) is now well recognized, however their molecular and functional diversity and underlying mechanisms still remain controversial. To transcriptionally and functionally characterize the diversity of microglia in AD and aging, we isolated the amyloid plaque-c...
Article
Lipid-based formulations (LBF) are widely used by industry and accepted by the regulatory authorities for oral drug delivery in the pharmaceutical and consumer healthcare market. Innovation in the LBF field is however needed in order to meet the demands of modern drugs, their more challenging problem statements and growing needs for achieving optim...
Article
The development of inhalable 'nanomedicines' based on biocompatible lipids and polymers is attracting increasing interest worldwide. Our understanding of how pulmonary inflammation impacts on lung distribution and clearance kinetics however, is limited. Similarly, there is limited information on how the inhaled delivery of biocompatible nanomateria...
Article
Self-dispersing lipid-based formulations, particularly self-microemulsifying drug delivery systems (SMEDDS) have gained an increased interest in recent times as a means to enhance the oral bioavailability of poorly water-soluble lipophilic drugs. Upon dilution, SMEDDS self-emulsify in an aqueous fluid and usually form a kinetically stable oil-in-wa...
Article
Full-text available
An iconic textbook that pharmaceutical scientists encounter in undergraduate courses is “Martin's Physical Pharmacy and Pharmaceutical Sciences.” Within the chapter on Colloids, a figure indicates the location of solubilization of molecules within spherical, nonionic surfactant micelles. The surfactant consists of polyethylene glycol (PEG) hydrophi...
Article
Molecular dynamics simulations can be applied to explore the complex liquid phase behaviour of lipid based formulations and the gastrointestinal tract lumen. In order for the results from these simulations to be of value, the manner in which molecules interact with both aqueous and oil phases present needs to be as correct as possible. An existing...
Article
Polyethoxylated, nonionic surfactants are important constituents of many drug formulations, including lipid-based formulations. In an effort to better understand the behavior of formulation excipients at the molecular level, we have developed molecular dynamics (MD) models for the widely used surfactant Kolliphor EL (KOL), a triricinoleate ester of...
Article
Full-text available
The absolute bioavailability of many small molecule kinase inhibitors (smKIs) is low. The reasons for low bioavailability are multifaceted and include constraints due to first pass metabolism and poor absorption. For smKIs where absorption limits oral bioavailability, low aqueous solubility and high lipophilicity, often in combination with high-dos...
Article
A series of 5-substituted tetrahydroisoquinolines was synthesised via a 10-step linear synthesis to assess whether replacement of noscapine’s southern isobenzofuranone with other moieties retained cytotoxic activity. One such molecule, 18g bearing a para-methoxybenzyl functionality with N-ethylcarbamoyl substitution produced cell cycle arrest at th...
Conference Paper
Full-text available
Introduction Hyperactivation of the PI3K signalling is common in cancers but the precise role of the pathway in glioma biology remains to be determined. Some understanding of PI3K signalling mechanisms in brain cancer comes from studies on neural stem/progenitor cells, where signals transmitted via the PI3K pathway cooperate with other intracellula...
Article
Background: Hyperactivation of PI3K signaling is common in cancers but the precise role of the pathway in glioma biology remains to be determined. Some understanding of PI3K signaling mechanisms in brain cancer comes from studies on neural stem/progenitor cells, where signals transmitted via the PI3K pathway cooperate with other intracellular path...
Article
Full-text available
The ability of lipid based formulations (LBFs) to increase the solubilization, and prolong the supersaturation, of poorly water-soluble drugs (PWSDs) in the gastro-intestinal (GI) fluids has generated significant interest in the last decade. One mechanism to enhance the utility of LBFs is to prolong supersaturation via the addition of polymers to t...
Article
Full-text available
Background: Poly(d,l-lactide-co-glycolide) (PLGA) based biodegradable nanoparticles are of key interest for the development of controlled release drug delivery systems and for other biomedical applications. It has been reported that PLGA polymers can be converted into colloidal nanoparticulate systems by various techniques, such as emulsification-...
Article
Background and purpose: Human amnion epithelial cells (hAECs) are nonimmunogenic, nontumorigenic, anti-inflammatory cells normally discarded with placental tissue. We reasoned that their profile of biological features, wide availability, and the lack of ethical barriers to their use could make these cells useful as a therapy in ischemic stroke. M...
Article
The utility of biodegradable nanosized drug carriers for the local and controlled delivery of therapeutics to the lungs has prompted significant interest in the development of inhalable nanomedicines. Still, little is known about how these systems are cleared from the lungs, including the kinetics of the structural lipids. Most preclinical and clin...
Article
Full-text available
Non-viral delivery systems are relatively safe but inefficient in their current form. The main obstacle in using non-viral gene delivery system approach is to transport the gene of interest in cytoplasm and subsequently entering into cell nucleus. In this research, palmityol-CKKHH and its series have been designed and its ability to form nanopartic...
Article
Full-text available
Non-viral delivery systems are relatively safe but inefficient in their current form. The main obstacle in using non-viral gene delivery system approach is to transport the gene of interest in cytoplasm and subsequently entering into cell nucleus. In this research, palmityol-CKKHH and its series have been designed and its ability to form nanopartic...
Article
Full-text available
Pluripotent stem cells (PSCs) are a valuable tool for interrogating development, disease modelling, drug discovery and transplantation. Despite the burgeoned capability to fate restrict human PSCs to specific neural lineages, comparative protocols for mouse PSCs have not similarly advanced. Mouse protocols fail to recapitulate neural development, c...
Article
In this study, we use molecular dynamics (MD) and experimental techniques (nephelometry and dynamic light scattering) to investigate the influence of cholesterol content and pH on the colloidal structures that form in the gastrointestinal (GI) tract upon lipid digestion. We demonstrate that the ionization state of the molecular species is a primary...
Article
In this study we determined the in vivo activity of model ovalbumin vaccines delivered by direct intramuscular delivery of plasmid DNA or oral delivery using a recombinant suicidal Listeria monocytogenes strain (rsΔ2). In a previous report we described how rsΔ2 is capable of delivering luciferase, as protein or DNA, in vitro, into non-dividing inte...
Article
Full-text available
Development of safe and effective stem cell-based therapies for brain repair requires an in-depth understanding of the in vivo properties of neural grafts generated from human stem cells. Replacing dopamine neurons in Parkinson's disease remains one of the most anticipated applications. Here, we have used a human PITX3-EGFP embryonic stem cell line...
Article
PEGylated polylysine dendrimers are attractive and well tolerated inhalable drug delivery platforms that have the potential to control the release, absorption kinetics and lung retention time of conjugated drugs. The clinical application of these systems though, would likely require partial substitution of surface PEG groups with drug molecules tha...
Preprint
Hyperactivation of the PI3K signaling is common in human cancers, including gliomas, but the precise role of the pathway in glioma biology remains to be determined. Some limited understanding of PI3K signaling in brain cancer come from studies on neural stem/progenitor cells (NSPCs) where signals transmitted via the PI3K pathway cooperate with othe...
Article
Higher lipid solubility of lipophilic salt forms creates new product development opportunities for high-dose liquid-filled capsules. The purpose of this study was to determine if lipophilic salts of BCS Class I amlodipine and BCS Class III fexofenadine, ranitidine and metformin were better lipid formulation candidates than existing commercial salts...
Chapter
Here, we describe how peptide nucleic acid (PNA) probes can be used to enrich genomic DNA fractions to facilitate downstream analysis, such as the haplotype phasing of the isolated genomic pieces. This method enriches for polymorphic regions of fragmented chromosomes by physically separating the desired sequence and flanking regions. The PNA probes...
Article
Full-text available
Improved models of the gastrointestinal environment have great potential to assist the complex process of drug formulation. Molecular dynamics (MD) is a powerful method for investigating phase behaviour at a molecular level. In this study we use multiple MD simulations to calculate phase diagrams for bile before and after digestion. In these comput...
Article
In the developing ventral telencephalon, cells of the lateral ganglionic eminence (LGE) give rise to all medium spiny neurons (MSNs). This development occurs in response to a highly orchestrated series of morphogenetic stimuli that pattern the resultant neurons as they develop. Striatal MSNs are characterised by expression of dopamine receptors, do...
Article
The current studies sought to explore the impact of drug supersaturation and precipitation during the dispersion and digestion of lipid-based formulations (LBF), on in vivo absorption using a coupled in vitro digestion - in vivo perfusion absorption model. Fenofibrate absorption was evaluated from a number of LBFs with different solubilisation and...