Nucleic Acid-Functionalized Gold Nanorods Modulate Inflammation and Dysregulated Intestinal Barriers for Treatment of Ulcerative Colitis

Abstract

Traditional oral treatments for ulcerative colitis (UC) face marked limitations including their single therapeutic effect, potential off-target interactions, and toxic side effects. In this study, we present nucleic acid-functionalized gold nanorods (NAF AuNRs), a biocompatible nanomaterial designed for the oral treatment of dextran sulfate sodium (DSS)-induced colitis. The NAF AuNRs alleviate immune responses by inhibiting pro-inflammatory macrophages and enhancing the expression of barrier proteins in intestinal epithelial cells. Due to the negatively charged nucleic acid shell, NAF AuNRs preferentially target anionic, inflamed colon tissues upon oral administration, reducing pro-inflammatory cytokine levels and promoting the recovery of intestinal barrier in DSS-induced colitis mice. Collectively, these findings suggest that NAF AuNRs represent an innovative and promising therapeutic approach for UC management, offering novel insights into the application of nucleic acid-functionalized nanomaterials.

Fig. 1.

Schematic illustration for the therapeutic mechanism of NAF AuNRs for the targeted treatment of UC.

Fig. 2.

Preparation and characterization of NAF AuNRs. (A) Schematic design of the preparation of NAF AuNRs. (B) TEM image and (C) size distribution of AuNRs. Absorption spectrum of AuNRs and NAF AuNRs at the range from 400 to 1,000 nm (D), and from 210 to 350 nm (E). (F) Dynamic light scattering (DLS) results and (G) zeta potential of the AuNRs and NAF AuNRs. Cell viability of (H) HT-29 cells and (I) RAW 264.7 cells at 24 and 48 h measured by the CCK-8 assay after the NAF AuNR treatment.

Fig. 3.

Anti-inflammation and barrier recovery of NAF AuNRs in vitro. (A) Schematic representation of NAF AuNR treatment for the LPS-stimulated mouse peritoneal macrophages and HT-29 cells. (B) Real-time quantitative PCR (RT-qPCR) analysis of the gene expression of TNF-α and IL-6 of LPS-stimulated mouse peritoneal macrophages (effect size of η² = 0.990 and 0.978). (C) ELISA results of pro-inflammatory cytokines including TNF-α, IL-6, and IL-1β from the supernatant of LPS-stimulated mouse peritoneal macrophages (effect size of η² = 0.980, 0.983, and 0.836). RT-qPCR analysis of the gene expression of (D) occludin and (E) mucin-2 of LPS-stimulated HT-29 cells (effect size of η² = 0.840 and 0.997). (F) WB results of occludin and mucin-2 of LPS-stimulated HT-29 cells (effect size of η² = 0.788 and 0.840). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

Fig. 4.

Evaluation of the efficacy of NAF AuNR treatment in the mice with DSS-induced UC. (A) Schematic illustration of the establishment and therapeutic schedule of the DSS-induced UC mice. (B) Macroscopic colon appearance of mice with different treatments. (C) Colon length of mice with different treatments (effect size of η² = 0.866). (D) Body weight and (E) DAI score change in each group for 7 d. (F) Representative images of H&E staining image and HAI of each group (effect size of η² = 0.984). Scale bar, 50 μm. ***P < 0.001, ****P < 0.0001.

Fig. 5.

Anti-inflammation efficacy and recovery of impaired intestinal barrier of NAF AuNRs in vivo. (A) Schematic representation of evaluation methods. RT-qPCR analysis of the gene expression of (B) TNF-α and IL-6, and (C) ZO-1 and occludin of colon tissues in each group (effect size of η² = 0.867, 0.928, 0.867, and 0.774). WB results of (D) ZO-1, (E) claudin-1, (F) occludin, and mucin-2 of colon tissues in each group (effect size of η² = 0.753, 0.957, 0.883, and 0.970). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

Fig. 6.

Therapeutic effect evaluation of NAF AuNRs in vivo through histology staining. Representative IHC images for (A) IL-6 and (B) TNF-α in each group. Representative IF staining and quantification of (C) ZO-1, (D) claudin-1, and (E) mucin-2 staining (effect size of η² = 0.983, 0.992, and 0.979). Scale bar, 50 μm. **P < 0.01, ****P < 0.0001.