Biology subjects

Alameh, M.-G.

Publications and source records attributed to Alameh, M.-G..

6 recordsLinked to original sources

bioRxiv2023

Development of a nucleoside-modified mRNA vaccine against clade 2.3.4.4b H5 highly pathogenic avian influenza virus

Highly pathogenic avian influenza viruses from H5 clade 2.3.4.4b are circulating at unprecedently high levels in wild and domestic birds and have the potential to adapt to humans. We generated an mRNA lipid nanoparticle (LNP) vaccine encoding the hemagglutinin (HA) glycoprotein from a clade 2.3.4.4b H5 isolate. We show that the vaccine is immunogenic in mice and ferrets and prevents morbidity and mortality of ferrets following 2.3.4.4b H5N1 challenge.

microbiology↗

bioRxiv2023

The Regulation of Nucleic Acid Vaccine Responses by the Microbiome

SummaryNucleic acid vaccines, including both RNA and DNA platforms, are key technologies that have considerable promise in combating both infectious disease and cancer. However, little is known about the extrinsic factors that regulate nucleic acid vaccine responses and which may determine their effectiveness. The microbiome is recognized as a significant regulator of immune development and response, whose role in regulating some traditional vaccine platforms has recently been discovered. Using germ-free and specific-pathogen-free mouse models in combination with different protein, DNA, and mRNA vaccine regimens, we demonstrate that the microbiome is a significant regulator of nucleic acid vaccine immunogenicity. While the presence of the microbiome enhances CD8+ T cell responses to mRNA lipid nanoparticle (LNP) immunization, the microbiome suppresses immunoglobulin and CD4+ T cell responses to DNA-prime, DNA-protein-boost immunization, indicating contrasting roles for the microbiome in the regulation of these different nucleic acid vaccine platforms. In the case of mRNA-LNP vaccination, germ-free mice display reduced dendritic cell/macrophage activation that may underlie the deficient vaccine response. Our study identifies the microbiome as a relevant determinant of nucleic acid vaccine response with implications for their continued therapeutic development and deployment.

immunology↗

bioRxiv2022

Lipid Nanoparticle Composition Drives Delivery of mRNA to the Placenta

Ionizable lipid nanoparticles (LNPs) have gained attention as mRNA delivery platforms for vaccination against COVID-19 and for protein replacement therapies. LNPs enhance mRNA stability, circulation time, cellular uptake, and preferential delivery to specific tissues compared to mRNA with no carrier platform. However, LNPs have yet to be developed for safe and effective mRNA delivery to the placenta as a method to treat placental dysfunction. Here, we develop LNPs that enable high levels of mRNA delivery to trophoblasts in vitro and to the placenta in vivo with no toxicity. We conducted a Design of Experiments to explore how LNP composition, including the type and molar ratio of each lipid component, drives trophoblast and placental delivery. Our data revealed that a specific combination of ionizable lipid and phospholipid in the LNP design yields high transfection efficiency in vitro. Further, we present one LNP platform that exhibits highest delivery of placental growth factor mRNA to the placenta in pregnant mice, which demonstrates induced protein synthesis and secretion of a therapeutic protein. Lastly, our high-performing LNPs have no toxicity to both the pregnant mice and fetuses. Our results demonstrate the feasibility of LNPs as a platform for mRNA delivery to the placenta. Our top LNPs may provide a therapeutic platform to treat diseases that originate from placental dysfunction during pregnancy.

bioengineering↗

bioRxiv2022

mRNA-based vaccines against SARS-CoV-2 do not stimulate interferon stimulatory gene expression in individuals affected by Aicardi Goutieres Syndrome.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses threats to individuals with rare disease, in part because so little is known about the impact of COVID-19 infection and vaccination safety in rare disease populations. Of particular concern, given the overlap in disease manifestations and interferon dysregulation, are a group of heritable autoinflammatory conditions called type I interferonopathies. The most common of these, Aicardi Goutieres Syndrome (AGS), is caused by altered nucleic acid metabolism and sensing, resulting in additional concerns surrounding the use of mRNA vaccination approaches. To determine whether mRNA vaccines induce an interferon response in AGS, we applied mRNA SARS-CoV-2 vaccines to whole blood samples and assessed internalization and interferon signaling gene expression responses to the mRNA. In all cases (11 AGS and 11 control samples), interferon signatures did not significantly increase from baseline, regardless of baricitinib treatment status in the AGS subjects, and were even decreased, when using codon optimized SARS-CoV-2 di-proline modified spike sequence (S2P). Internalization of S2P in human dendritic cells was verified by Western Blot, and in control and AGS blood cells was verified by Luciferase activity. Although numbers of tested samples in this rare disease are small, based on these findings, we suggest that COVID vaccination is unlikely to directly stimulate the interferon signaling gene expression in AGS patients via response to mRNA internalization. The in vitro nature of this study cannot exclude an exaggerated interferon response to spike protein production at a systemic level in individuals with a primary heritable interferonopathy. In the context of continued SARS-CoV-2 spread in the community, we do not recommend withholding vaccination in this rare disease group. However, we recommend that vaccinations for AGS patients are provided in a controlled setting with appropriate observation and used with caution in individuals with prior vaccine associated adverse events.

immunology↗

bioRxiv2022

Lipid nanoparticles delivering constitutively active STING mRNA as a novel anti-cancer therapeutic approach

Treating immunosuppressive tumors represents a major challenge in cancer therapies. Activation of STING signaling has shown remarkable potential to invigorate the immunologically cold tumor microenvironment (TME). However, we and others have shown that STING is silenced in many cancers, including pancreatic ductal adenocarcinoma (PDAC) and Merkel cell carcinoma (MCC), both of which are associated with an immune-dampened TME. In this study, we applied mRNA lipid nanoparticles (LNP) to deliver a permanently active gain-of-function STINGR284S mutant into PDAC and MCC cells. Expression of STINGR284S induces cytokines and chemokines crucial for promoting intratumoral infiltration of CD8+ T cells and, importantly, also leads to robust cancer cell death while avoiding T cell entry and toxicity. Our studies demonstrated that mRNA-LNP delivery of STINGR284S could be explored as a novel therapeutic tool to reactivate antitumor response in an array of STING-deficient cancers while overcoming the toxicity and limitations of conventional STING agonists.

bioengineering↗

bioRxiv2021

Combinatorial mRNA vaccination enhances protection against SARS-CoV-2 delta variant

Emergence of SARS-CoV-2 variants of concern (VOC), including the highly transmissible delta strain, has posed challenges to current COVID-19 vaccines that principally target the viral spike protein (S). Here, we report a nucleoside-modified mRNA vaccine that expresses the more conserved viral nucleoprotein (mRNA-N). We show that mRNA-N alone was able to induce a modest but significant control of SARS-CoV-2 in mice and hamsters. Critically, by combining mRNA-N with the clinically approved S-expressing mRNA vaccine (mRNA-S-2P), we found that combinatorial mRNA vaccination (mRNA-S+N) led to markedly enhanced protection against the SARS-CoV-2 delta variant compared to mRNA-S. In a hamster model, we demonstrated that while mRNA-S alone elicited significant control of the delta strain in the lungs ([~]45-fold reduction in viral loads compared to un-vaccinated control), its effectiveness in the upper respiratory tract was weak, whereas combinatorial mRNA-S+N vaccination induced markedly more robust control of the delta variant infection in the lungs ([~]450-fold reduction) as well as in the upper respiratory tract ([~]20-fold reduction). Immune analyses indicated that induction of N-specific immunity as well as augmented S-specific T-cell response and neutralizing antibody activity were collectively associated the enhanced protection against SARS-CoV-2 delta strain by combinatorial mRNA vaccination. These findings suggest that the combined effects of protection in the lungs and upper respiratory tract could both reduce the risk of severe disease as well as of infection and transmission.

microbiology↗