Enhancement of the Tolerogenic Phenotype in the Liver by ImmTOR Nanoparticles

Abstract

ImmTOR biodegradable nanoparticles encapsulating rapamycin have been shown to induce a durable tolerogenic immune response to co-administered biologics and gene therapy vectors. Prior mechanism of action studies have demonstrated selective biodistribution of ImmTOR to the spleen and liver following intravenous (IV) administration. In the spleen, ImmTOR has been shown to induce tolerogenic dendritic cells and antigen-specific regulatory T cells and inhibit antigen-specific B cell activation. Splenectomy of mice resulted in partial but incomplete abrogation of the tolerogenic immune response induced by ImmTOR. Here we investigated the ability of ImmTOR to enhance the tolerogenic environment in the liver. All the major resident populations of liver cells, including liver sinusoidal endothelial cells (LSECs), Kupffer cells (KC), stellate cells (SC), and hepatocytes, actively took up fluorescent-labeled ImmTOR particles, which resulted in downregulation of MHC class II and co-stimulatory molecules and upregulation of the PD-L1 checkpoint molecule. The LSEC, known to play an important role in hepatic tolerance induction, emerged as a key target cell for ImmTOR. LSEC isolated from ImmTOR treated mice inhibited antigen-specific activation of ovalbumin-specific OT-II T cells. The tolerogenic environment led to a multi-pronged modulation of hepatic T cell populations, resulting in an increase in T cells with a regulatory phenotype, upregulation of PD-1 on CD4+ and CD8+ T cells, and the emergence of a large population of CD4–CD8– (double negative) T cells. ImmTOR treatment protected mice in a concanavalin A-induced model of acute hepatitis, as evidenced by reduced production of inflammatory cytokines, infiltrate of activated leukocytes, and tissue necrosis. Modulation of T cell phenotype was seen to a lesser extent after administration by empty nanoparticles, but not free rapamycin. The upregulation of PD-1, but not the appearance of double negative T cells, was inhibited by antibodies against PD-L1 or CTLA-4. These results suggest that the liver may contribute to the tolerogenic properties of ImmTOR treatment.

Treatment of metabolic disorders using genomic technologies: Lessons from methylmalonic acidemia

“…ImmTOR is a tolerogenic nanoparticle encapsulating rapamycin. [79][80][81][82] (B) A human, codon-optimized hMMUT mRNA encapsulated in a lipid nanoparticle. (C) The schematic of an AAV-mediated, nuclease-free genome editing vector and the integration and subsequent expression.…”

“…AAV inverted terminal repeats (ITRs) flank a single‐stranded DNA sequence comprised of a promoter (either ubiquitous or tissue/liver‐specific), the MMUT transgene (either a mouse or human cDNA), and a polyA sequence. ImmTOR is a tolerogenic nanoparticle encapsulating rapamycin 79–82 . (B) A human, codon‐optimized hMMUT mRNA encapsulated in a lipid nanoparticle.…”

“…One proposed method to prevent antibodies from forming in response to gene therapy is to co-administer rapamycin. Selecta Biosciences has developed a tolerogenic nanoparticle that encapsulates rapamycin known as ImmTOR (Figure 2A), [79][80][81][82] which causes long-term suppression of humoral and T cell responses when coadministered with an AAV therapy. 80,96 When combining ImmTOR with an MMUT rAAV in the Mmut À/À ; Tg INSÀMCKÀMmut mouse model, we observed rapid weight gain, reduced plasma methylmalonic acid, and lowering of Fgf21 levels.…”

Tolerogenic nanoparticles mitigate the formation of anti-drug antibodies against pegylated uricase in patients with hyperuricemia

“…However, in vitro studies have shown that rapamycin can also induce tolerogenic antigen presenting cells (APCs) which promote activation of regulatory T cells 11 . ImmTOR nanoparticles show selective biodistribution to the spleen and liver following intravenous administration where they are taken up by antigen-presenting cells (APCs) 9 , 12 – 14 . ImmTOR induces a tolerogenic phenotype in dendritic cells in the spleen 9 and in liver sinusoidal endothelial cells and other APCs in the liver 12 (Fig.…”

“…ImmTOR nanoparticles show selective biodistribution to the spleen and liver following intravenous administration where they are taken up by antigen-presenting cells (APCs) 9 , 12 – 14 . ImmTOR induces a tolerogenic phenotype in dendritic cells in the spleen 9 and in liver sinusoidal endothelial cells and other APCs in the liver 12 (Fig. 1 ).…”