Mohamad Gabriel Alameh, Ph.D.

faculty photo
Assistant Professor of Pathology and Laboratory Medicine
Director, Engineered mRNA and Targeted Nanomedicine Core
Department: Pathology and Laboratory Medicine

Contact information
3450 Hamilton Walk
Room 109A
Philadelphia, PA 19104
B.SC (Microbiology and Immunology)
University of Montreal, 2006.
M.Sc (Theoretical Molecular Biology )
University of Montreal, 2009.
Ph.D. (Nanotechnology and Nanomedicine )
Polytechnique Montreal, 2017.
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Description of Other Expertise

Companies, and professional contributions

I have founded, and currently managing the Engineered mRNA and Targeted Nanomedicine core at the University of Pennsylvania to address infrastructural barrier to clinical and translational research in gene therapy, vaccine development (cancer and infectious disease), stem cell reprograming, and other non-viral gene therapy based applications by designing and providing high quality in vitro transcribed messenger RNA (IVT-mRNA) and lipid nanoparticles. The core established more than 100 academic and industrial collaborations since its inception, and generates around $250 000 in profit per year. I have also co-founded

AexeRNA therapeutics to develop potent and non-toxic lipid nanoparticles. I started as the head of platforms, and now the acting CSO of the company. I lead the development of novel LNPs, and play a key role in licensing discussion/negotiations with multiple big pharmaceutical companies.

I also implemented a cGMP manufacturing process for mRNA, and mRNA-LNP in South Africa as part of a United Nation Sponsored program to capacitate low and middle income countries (LMIC). In this project, I helped design the manufacturing process (0.1, 1 and 10L batches), select equipment, and directed the development of the analytical assays for batch validation and release.

Description of Research Expertise

1) Chitosan based polymeric systems for the in vivo delivery of small interfering RNA. I have elucidated the effect of different intrinsic and extrinsic parameters on the formation of chitosan- siRNA nanoparticles and established the design principles for this systems. I showed that in vitro and in vivo performance of chitosan-siRNA nanoparticles is a function of molecular weight, charge, amine to phosphate ratio, pH, ionic strength, and percent of protein. Increased molecular weight, and charge density promoted improved colloidal stability, and protection of the siRNA cargo in serum, and that a minimum of 5kDa is required for efficient in vitro transfection. I demonstrated that improved in vitro transfection due to an increase in free chitosan is not needed in vivo, and that chitosan-siRNA accumulate, and induce functional knockdown in the proximal epithelial tubular cells (PTEC) of the kidney without causing local or systematic toxicity up to a dose of 3mg/kg. I showed that increased accumulation of chitosan-siRNA nanoparticles is molecular weight dependent. I also developed a method to assess siRNA encapsulation efficiency, and integrity following encapsulation with chitosan, and have tested the system for the delivery of plasmid DNA, and mRNA. I showed that different design principles, and parameters are needed for the delivery of each type of nucleic acid, and that avidity of the interaction has a deleterious effect on in vitro and in vivo performance. The work has led to the submission of a patent application and the creation of a spin-off company for the development of chitosan based siRNA delivery systems for the treatment for kidney diseases.

2) Adjuvant activity of ionizable lipids, and development of novel LNPs.

I demonstrated that the potency of the current approved mRNA-LNP vaccines is due to the ionizable lipid component, and showed that the adjuvant effect is mediated through the induction of a particular cytokines and chemokines signature that include IL-6, IL-1, IL-27, IL-21, KC, and MIP-1 among others. I also showed that the ionizable lipid induce the activation and proliferation of T follicular helper (TFH) cells through IL-6 and IL-21, and is considered a TFH adjuvant. Abrogation of IL-6 expression using transgenic KO mice or blocking of circulating IL-6 and 21 reduced the adjuvant activity of the ionizable lipid, and abrogated germinal center reactions and TFH activation/proliferation. Using MAVS, and MyD88 transgenic mice, my work showed that the induction of this potent reaction is independent of these two adaptor protein. Transcriptomic analysis using RNASeq on human dendritic cells (DCs) identified multiple signaling pathways and highlighted the role of two sensors, and a transcription factor in the activation and maturation of DCs following transfection with LNPs. Most importantly, I have showed that the transcriptomic and cytokine profiles differs with different ionizable lipids laying the foundation that specific features on the lipids/LNPs play important roles in the induction of the immune response through interaction with molecular sensors or direct activation of proteins involved in the activation of immune response. I also showed that both the magnitude and quality of cytokine following incubation of LNP with PBMCs from healthy individuals is strongly influenced by age. Expression of TGF-β isoforms was significantly increased in aged individual partially explaining poorer GC reactions, and lower antibody responses.

In collaboration with multiple groups, I have shown that the inclusion of dexamethasone or a lipid- conjugated TLR-7 agonist at different molar ratios during formulation allow fine tuning of the inflammatory response. We also demonstrated that IL-27 and IL-12 play an important role for improved T cell responses in the context of mRNA-LNP vaccines, and are working to using cytokines to tweak immune responses following mRNA-LNP vaccination. These contributions are crucial for the optimization and improvement of mRNA- based vaccines, and the development of novel LNPs and have led to the submission of multiple provisional patent applications.

3) Development of mRNA based Vaccines for C. difficile, SARS-CoV-2 and other pathogens in young and aged animals.

I designed and developed a multivalent mRNA vaccine that targets disease causing toxins and a protease involved in the attachment of C. difficile to the gut mucosa/extracellular matrix. The trivalent vaccine demonstrated complete protection in animals following either toxin (up to 5 LD100) or bacterial challenge (up to 10 LD100), and was able to decolonize the gut of mice despite poor mucosal responses. I was also awarded a grant from the Coalition for Epidemic Preparedness Innovations (CEPI) for the development of a multivalent in vivo Virus like Particle forming mRNA-LNP platform. I demonstrated that the delivery of such structural proteins encoded on nucleoside modified mRNA are able to form VLPs in vivo, and improve immune responses compared to current vaccines. Multipronged, and multifunctional T cell responses were shown, and higher neutralization titers were achieved at a similar dose. Most importantly, the strategy showed broad protection in mice, hamsters and Non-human primate against different coronaviruses. Both the C. difficile and the VLP based vaccine platform resulted in provisional patent applications, and are now moving into phase I clinical trials. I have also contributed to the design, production, and conduction of multiple vaccine studies including mRNA-LNP vaccines against Malaria, Human Immunodeficiency Virus, Herpes Simplex Virus, and Veterinary pathogens.

Selected Publications

Han X, Alameh M-G, Butowska K, Knox JJ, Lundgreen K, Ghattas M, Gong N, Xue L, Xu Y, Lavertu M, Bates P, Xu J, Nie G, Zhong Y, Wiessman D, Mitchell MJ: Adjuvant lipidoid-substituted lipid nanoparticles augment the immunogenicity of SARS-CoV-2 mRNA vaccines. Nat Nanotechnol June 2023 (epub ahead of print) Notes: doi: 10.1038/s41565-023-01404-4.

Brooks DL, Carrasco MJ, Qu P, Peranteau WH, Ahrens-Nicklas RC, Musunuru K, Alameh M-G*, Wang X* (* co-senior and co-corresponding authors): Rapid and definitive treatment of phenylketonuria in variant-humanized mice with corrective editing Nat Commun 14(1): 3451, June 2023.

Chuang Y-M, Alameh M-G, Abouneameh S, Raduwan H, Ledizet M, Weissman D, Fikrig E: A mosquito AgTRIO mRNA vaccine contributes to immunity against malaria. NPJ Vaccines 8(1): 88, June 2023.

Furey C, Ye N, Kercher L, DeBeauchamp J, Crumpton JC, Jeevan T, Patton C, Franks J, Alameh MG, Fan SHY, Phan AT, Hunter CA, Webby RJ, Weissman D, Hensley SE.: Development of a nucleoside-modified mRNA vaccine against clade H5 highly pathogenic avian influenza virus. bioRxiv Page: 04.30.538854, Apr 2023.

Prompetchara E, Ketloy C, Alameh MG, Tharakhet K, Kaewpang P, Yostrerat N, Pitakpolrat P, Buranapraditkun S, Manopwisedjaroen S, Thitithanyanont A, Jongkaewwattana A, Hunsawong T, Im-Erbsin R, Reed M, Wijagkanalan W, Patarakul K, Techawiwattanaboon T, Palaga T, Lam K, Heyes J, Weissman D, Ruxrungtham K.: Immunogenicity and protective efficacy of SARS-CoV-2 mRNA vaccine encoding secreted non-stabilized spike in female mice. Nat Commun 14(1): 2309, Apr 2023.

Riera-Domingo C, Leite-Gomes E, Charatsidou I, Zhao P, Carrá G, Cappellesso F, Mourao L, De Schepper M, Liu D, Serneels J, Alameh MG, Shuvaev VV, Geukens T, Isnaldi E, Prenen H, Weissman D, Muzykantov VR, Soenen S, Desmedt C, Scheele CLGJ, Sablina A, Di Matteo M, Martín-Pérez R, Mazzone M.: Breast tumors interfere with endothelial TRAIL at the premetastatic niche to promote cancer cell seeding. Sci Adv 9(12): eadd5028, Mar 2023.

Swingle KL, Safford HC, Geisler HC, Hamilton AG, Thatte AS, Billingsley MM, Joseph RA, Mrksich K, Padilla MS, Ghalsasi AA, Alameh MG, Weissman D, Mitchell MJ.: Ionizable Lipid Nanoparticles for In Vivo mRNA Delivery to the Placenta during Pregnancy. J Am Chem Soc 145(8): 4691-4706, Mar 2023.

David D, Alameh MG, Isaac J, Mu C, Nelson A, Shen S, Montefiori D, Pllera J, Wiehe K, Weissman D, Haynes B, Permar S, De Paris K : HIV-1 Envelope mRNA Vaccination Induces Higher Env-specific Antibody Responses in Infant Compared to Juvenile Rhesus Macaques. Proceedings of Keystone Symposia, Banff, AB, Canada Feb 2023.

Connors J, Joyner D, Mege NJ, Cusimano GM, Bell MR, Marcy J, Taramangalam B, Kim KM, Lin PJC, Tam YK, Weissman D, Kutzler MA, Alameh MG, Haddad EK.: Lipid nanoparticles (LNP) induce activation and maturation of antigen presenting cells in young and aged individuals. Commun Biol 6(1): 188, Feb 2023.

Johnson AMF, Hager K, Alameh MG, Van P, Potchen N, Mayer-Blackwell K, Fiore-Gartland A, Minot S, Lin PJC, Tam YK, Weissman D, Kublin JG.: The Regulation of Nucleic Acid Vaccine Responses by the Microbiome. bioRxiv Page: 02.18.529093, Feb 2023.

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Last updated: 09/19/2023
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