Lipid nanoparticle delivers phenylalanine ammonia lyase mRNA to the liver leading to catabolism and clearance of phenylalanine in a phenylketonuria mouse model.

Phenylketonuria (PKU) is a genetic disorder affecting around 1 in 12,000 live births (1), caused by a mutation in the phenylalanine hydroxylase (PAH) gene in the liver which facilitates the catabolism of phenylalanine (Phe). Without a functional copy of PAH, levels of Phe in the blood and tissues rise, resulting in potentially life-threatening damage to the central nervous system. (2) Treatment options for PKU are limited, and center around adherence to a strict PKU diet that suffers from poor patient compliance. There are two approved drugs available, one of which must be used in conjunction with the PKU diet and another that has serious immunological side effects. Here we demonstrate that the LUNAR® delivery technology is capable of delivering mRNA for a replacement enzyme, the bacterial phenylalanine ammonia lyase (avPAL), into the hepatic tissue of a PKU mouse, and that the enzyme is capable of metabolizing Phe and reducing serum levels of Phe for more than five days post-transfection. We further demonstrate the ability of LUNAR to deliver a plant-derived PAL protein with a similar impact on the level of serum Phe. Taken together these results demonstrate both the capability of LUNAR for the targeted delivery of PAL mRNA into hepatic tissue in vivo, replacing the defective PAH protein and successfully reducing serum Phe levels, thereby addressing the underlying cause of PKU symptoms. Secondly, that plant-based PAL proteins are a viable alternative to bacterial avPAL to reduce the immunogenic response.

A single dose of self-transcribing and replicating RNA-based SARS-CoV-2 vaccine produces protective adaptive immunity in mice.

A self-transcribing and replicating RNA (STARR)-based vaccine (LUNAR-COV19) has been developed to prevent SARS-CoV-2 infection. The vaccine encodes an alphavirus-based replicon and the SARS-CoV-2 full-length spike glycoprotein. Translation of the replicon produces a replicase complex that amplifies and prolongs SARS-CoV-2 spike glycoprotein expression. A single prime vaccination in mice led to robust antibody responses, with neutralizing antibody titers increasing up to day 60. Activation of cell-mediated immunity produced a strong viral antigen-specific CD8+ T lymphocyte response. Assaying for intracellular cytokine staining for interferon (IFN)γ and interleukin-4 (IL-4)-positive CD4+ T helper (Th) lymphocytes as well as anti-spike glycoprotein immunoglobulin G (IgG)2a/IgG1 ratios supported a strong Th1-dominant immune response. Finally, single LUNAR-COV19 vaccination at both 2 µg and 10 µg doses completely protected human ACE2 transgenic mice from both mortality and even measurable infection following wild-type SARS-CoV-2 challenge. Our findings collectively suggest the potential of LUNAR-COV19 as a single-dose vaccine.