Gastrointestinal delivery of mRNA lipid nanoparticles selectively targets the pancreas

Abstract

Lipid nanoparticles (LNPs) administered parenterally often show poor localization to the gastrointestinal (GI) tract and pancreas. In addition, patients typically prefer orally administered drugs to those given intravenously. We therefore investigated whether GI delivery, achievable via device mediated microneedle injections applied to buccal, gastric, small intestinal, colonic, or rectal tissues, could simultaneously enhance LNP delivery to the GI and pancreas while avoiding intravenous administration. Using a combined approach of formulation optimization and GI delivery site screening, we found that cationic SM-102 LNPs delivered gastrically achieved 7-fold higher pancreas delivery in rodents than intravenous neutral SM-102 LNPs. With dose optimization, gastric LNPs achieved 6000-fold greater pancreas to liver targeting ratios than intravenous LNPs. These results suggest GI microneedle administration can reprogram LNP biodistribution, thereby expanding therapeutic opportunities for both local and systemic nucleic acid delivery.

Figure 1.

In vivo gastrointestinal delivery of aNLuc mRNA with LNP^neut revealed pancreas-targeting upon stomach injection. a) aNLuc RNA was administered at 1 mg kg⁻¹ intravenously or into the buccal, colon, rectum, or stomach tissue. IVIS imaging at 18 h following dosing revealed luciferase expression. b) Formulation details of LNP^neut and physicochemical characteristics: hydrodynamic diameter (D_h), polydispersity index (PDI), and encapsulation efficiency. c) Total flux fold-change of pancreas compared to PBS-treated group. d) Percentage of pancreas total flux expression out of 10-organs:(e) liver, (f) lung, (g) heart, and (h) spleen, Stomach (Fig S3a), Colon (Fig S3b), Small intestine (Figure S3c), lymph nodes (Figure S3f), and kidney (Figure S3g). i) Heatmap showing total flux (fold-change) across administration routes of pancreas (green), off-target organs (red), and GI organs (orange). (n=3 mice. Individual data points, Mean +/− SEM. One-Way ANOVA with Tukey’s correction. *p< 0.05; **p<0.01; ***p<0.001; ****p<0.0001).

Figure 2.

LNP^cat increases pancreas-targeting over LNP^neut, with synergistic targeting effects seen when delivering via stomach compared to IV. a) aNLuc mRNA encapsulated in LNPcat was delivered via IV or stomach at 1 mg kg⁻¹. IVIS imaging 18h following dosing revealed luciferase expression. b) Formulation details of LNP^cat and physicochemical characteristics: hydrodynamic diameter (D_h), polydispersity index (PDI), and encapsulation efficiency. c) Total flux (fold-change) of pancreas across IV and stomach administered mRNA with LNP^neut vs LNP^cat compared to 1x PBS group. d) Heat map showing total flux (fold change) between LNP^neut and LNP^cat across both IV and stomach administration routes to the pancreas (green), and off-target organs (e) liver, (f) lung, (g) heart, and (h) spleen (red). Additional off target organs in Figure S4. i-j) dose response of LNP^cat formulated with aNLuc mRNA 18h post injection showing (i) total flux quantification of pancreas and (j) pancreas/liver ratio. k-l) Time-course of LNP^cat formulated with aNLuc mRNA delivered 0.3 mg kg⁻¹, at 4h, 12, 24h, 48h. Quantified are (k) total flux of pancreas and (l) pancreas/liver ratios. (n = 3–4 mice. Individual data points, Mean +/− SEM. Two-Way ANOVA with Tukey’s correction. *p<0.05; **p<0.01; ****p<0.0001.)

Figure 3.

Immunofluorescence targeting tdTomato following delivery of cre mRNA with LNP^cat in Ai14 mice shows targeted cell types in pancreas 5 days after delivery. IF and H&E staining shows targeting to multiple cell types.