Publications by authors named "Rakan El-Mayta"

Article Synopsis
  • * The study presents a method combining iterative chemical derivatization with combinatorial chemistry to enhance the design of propargylamine-based ionizable lipids (A-lipids), leading to improved delivery and biodegradability.
  • * After multiple optimization cycles, new A-lipids were found that deliver mRNA vaccines and editors more effectively than traditional ionizable lipids, showing promise for advancing LNPs in therapeutic applications.
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Systemic delivery of messenger RNA (mRNA) for tissue-specific targeting using lipid nanoparticles (LNPs) holds great therapeutic potential. Nevertheless, how the structural characteristics of ionizable lipids (lipidoids) impact their capability to target cells and organs remains unclear. Here we engineered a class of siloxane-based ionizable lipids with varying structures and formulated siloxane-incorporated LNPs (SiLNPs) to control in vivo mRNA delivery to the liver, lung and spleen in mice.

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Nanoparticles are promising for drug delivery applications, with several clinically approved products. However, attaining high nanoparticle accumulation in solid tumours remains challenging. Here we show that tumour cell-derived small extracellular vesicles (sEVs) block nanoparticle delivery to tumours, unveiling another barrier to nanoparticle-based tumour therapy.

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Lipid nanoparticles (LNPs) are widely used for mRNA delivery, with cationic lipids greatly affecting biodistribution, cellular uptake, endosomal escape and transfection efficiency. However, the laborious synthesis of cationic lipids limits the discovery of efficacious candidates and slows down scale-up manufacturing. Here we develop a one-pot, tandem multi-component reaction based on the rationally designed amine-thiol-acrylate conjugation, which enables fast (1 h) and facile room-temperature synthesis of amidine-incorporated degradable (AID) lipids.

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In situ cancer vaccination refers to any approach that exploits tumour antigens available at a tumour site to induce tumour-specific adaptive immune responses. These approaches hold great promise for the treatment of many solid tumours, with numerous candidate drugs under preclinical or clinical evaluation and several products already approved. However, there are challenges in the development of effective in situ cancer vaccines.

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Immune modulation through the intracellular delivery of nucleoside-modified mRNA to immune cells is an attractive approach for immunoengineering, with applications in infectious disease, cancer immunotherapy, and beyond. Lipid nanoparticles (LNPs) have come to the fore as a promising nucleic acid delivery platform, but LNP design criteria remain poorly defined, making the rate-limiting step for LNP discovery the screening process. In this study, we employed high-throughput LNP screening based on molecular barcoding to investigate the influence of LNP composition on immune tropism with applications in vaccines and systemic immunotherapies.

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Lipid nanoparticles for delivering mRNA therapeutics hold immense promise for the treatment of a wide range of lung-associated diseases. However, the lack of effective methodologies capable of identifying the pulmonary delivery profile of chemically distinct lipid libraries poses a significant obstacle to the advancement of mRNA therapeutics. Here we report the implementation of a barcoded high-throughput screening system as a means to identify the lung-targeting efficacy of cationic, degradable lipid-like materials.

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Cancer immunity is subjected to spatiotemporal regulation by leukocyte interaction with neoplastic and stromal cells, contributing to immune evasion and immunotherapy resistance. Here, we identify a distinct mesenchymal-like population of endothelial cells (ECs) that form an immunosuppressive vascular niche in glioblastoma (GBM). We reveal a spatially restricted, Twist1/SATB1-mediated sequential transcriptional activation mechanism, through which tumor ECs produce osteopontin to promote immunosuppressive macrophage (Mφ) phenotypes.

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The ionizable lipidoid is a key component of lipid nanoparticles (LNPs). Degradable lipidoids containing extended alkyl branches have received tremendous attention, yet their optimization and investigation are underappreciated. Here, we devise an in situ construction method for the combinatorial synthesis of degradable branched (DB) lipidoids.

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Article Synopsis
  • Researchers are working on a new medicine that helps T cells, a type of immune cell, fight cancer more effectively, but it can also cause side effects like unwanted toxicity and inflammation.
  • They found that a drug called amantadine can help separate the T cells from the tumor, reducing these side effects while still allowing the T cells to attack cancer cells.
  • In experiments with mice, this approach showed that the treatment targeted the tumors better and prevented them from coming back, making it a promising way to control cancer without harming the rest of the body.
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Lipid nanoparticles (LNPs) have emerged as a viable, clinically-validated platform for the delivery of mRNA therapeutics. LNPs have been utilized as mRNA delivery systems for applications including vaccines, gene therapy, and cancer immunotherapy. However, LNPs, which are typically composed of ionizable lipids, cholesterol, helper lipids, and lipid-anchored polyethylene glycol, often traffic to the liver which limits the therapeutic potential of the platform.

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With six therapies approved by the Food and Drug Association, chimeric antigen receptor (CAR) T cells have reshaped cancer immunotherapy. However, these therapies rely on ex vivo viral transduction to induce permanent CAR expression in T cells, which contributes to high production costs and long-term side effects. Thus, this work aims to develop an in vivo CAR T cell engineering platform to streamline production while using mRNA to induce transient, tunable CAR expression.

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Chimeric antigen receptor T (CAR T) cell immunotherapy is successful at treating many cancers. However, it often induces life-threatening cytokine release syndrome (CRS) and neurotoxicity. Here, we show that in situ conjugation of polyethylene glycol (PEG) to the surface of CAR T cells ('PEGylation') creates a polymeric spacer that blocks cell-to-cell interactions between CAR T cells, tumour cells and monocytes.

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Lipid nanoparticles (LNPs) are a potent delivery technology that have made it possible for the recent clinical breakthroughs in mRNA therapeutics and vaccines. A key challenge to the broader implementation of mRNA therapeutics and vaccines is the development of technology to produce precisely defined LNP formulations, with throughput that can scale from discovery to commercial manufacturing and meet the stringent manufacturing standards of the pharmaceutical industry. To address these challenges, we have developed a microfluidic chip that incorporates 1×, 10×, or 256× LNP-generating units that achieve scalable production rates of up to 17 L/h of precisely defined LNPs.

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Multiple myeloma (MM), a hematologic malignancy that preferentially colonizes the bone marrow, remains incurable with a survival rate of 3 to 6 mo for those with advanced disease despite great efforts to develop effective therapies. Thus, there is an urgent clinical need for innovative and more effective MM therapeutics. Insights suggest that endothelial cells within the bone marrow microenvironment play a critical role.

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Evasion of apoptosis is a hallmark of cancer, attributed in part to overexpression of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2). In a variety of cancer types, including lymphoma, Bcl-2 is overexpressed. Therapeutic targeting of Bcl-2 has demonstrated efficacy in the clinic and is the subject of extensive clinical testing in combination with chemotherapy.

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Lipid nanoparticles (LNPs) have attracted widespread attention recently with the successful development of the COVID-19 mRNA vaccines by Moderna and Pfizer/BioNTech. These vaccines have demonstrated the efficacy of mRNA-LNP therapeutics and opened the door for future clinical applications. In mRNA-LNP systems, the LNPs serve as delivery platforms that protect the mRNA cargo from degradation by nucleases and mediate their intracellular delivery.

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Lipid nanoparticle-mediated RNA delivery holds great potential to treat various liver diseases. However, targeted delivery of RNA therapeutics to activated liver-resident fibroblasts for liver fibrosis treatment remains challenging. Here, we develop a combinatorial library of anisamide ligand-tethered lipidoids (AA-lipidoids) using a one-pot, two-step modular synthetic method and adopt a two-round screening strategy to identify AA-lipidoids with both high potency and selectivity to deliver RNA payloads to activated fibroblasts.

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Article Synopsis
  • Myocardial infarction (MI), also known as a heart attack, is a major cause of death because there aren’t good ways to help the heart recover after it happens.
  • The study shows that after MI, the cells in blood vessels change in a way that causes problems, making it hard for the heart to heal.
  • Researchers found a specific process involving certain proteins that can make these blood vessel cells behave differently, and by blocking this process in mice, they were able to improve heart repair after an MI.
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A major challenge to advance lipid nanoparticles (LNPs) for RNA therapeutics is the development of formulations that can be produced reliably across the various scales of drug development. Microfluidics can generate LNPs with precisely defined properties, but have been limited by challenges in scaling throughput. To address this challenge, we present a scalable, parallelized microfluidic device (PMD) that incorporates an array of 128 mixing channels that operate simultaneously.

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In recent years, immune cell-based cancer therapeutics have been utilized broadly in the clinic. Through advances in cellular engineering, chimeric antigen receptor (CAR) T-cell therapies have demonstrated substantial success in treating hematological tumors and have become the most prominent cell-based therapy with three commercialized products in the market. However, T-cell-based immunotherapies have certain limitations, including a restriction to autologous cell sources to avoid severe side-effects caused by human leukocyte antigen (HLA) mismatch.

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Nucleic acids, such as messenger RNAs, antisense oligonucleotides, and short interfering RNAs, hold great promise for treating previously 'undruggable' diseases. However, there are numerous biological barriers that hinder nucleic acid delivery to target cells and tissues. While lipid nanoparticles (LNPs) have been developed to protect nucleic acids from degradation and mediate their intracellular delivery, it is challenging to predict how alterations in LNP formulation parameters influence delivery to different organs.

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Messenger RNA (mRNA) has recently emerged as a promising class of nucleic acid therapy, with the potential to induce protein production to treat and prevent a range of diseases. However, the widespread use of mRNA as a therapeutic requires safe and effective in vivo delivery technologies. Libraries of ionizable lipid nanoparticles (LNPs) have been designed to encapsulate mRNA, prevent its degradation, and mediate intracellular delivery.

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