Ultrasound‑responsive nano‑contrast agents co‑delivering CIITA‑siRNA and rapamycin for targeted therapy against Hashimoto thyroiditis

BACKGROUND: Hashimoto thyroiditis (HT) is a common autoimmune thyroid disease for which effective treatments capable of suppressing local autoimmune injury remain limited. This study aimed to develop an ultrasound-responsive anti-inflammatory nano-contrast agent (AINA) for the targeted delivery of CIITA-small interfering ribonucleic acid (CIITA-siRNA) and rapamycin to thyroid tissue. METHODS: Thyroid tissue samples were obtained from patients undergoing total thyroidectomy at Qilu Hospital of Shandong University from March to April 2024. After pathological evaluation, samples from three patients with HT and three patients without HT were included. CIITA and HLA-DR expression was assessed using transcriptomic sequencing and quantitative reverse transcription polymerase chain reaction. AINAs were constructed with an erythrocyte-membrane shell carrying rapamycin and a core containing CIITA-siRNA-loaded, trans-activator of transcription (TAT)-modified mesoporous silica nanoparticles and liquid perfluorohexane. Their physicochemical properties, ultrasound imaging performance, cellular uptake, therapeutic effects, and preliminary safety were evaluated in Nthy-ori 3-1 cells, Jurkat cells, and NOD.H-2h4 mice. RESULTS: AINAs had a mean diameter of 255 nm and a polydispersity index of 0.23. More than 90% of CIITA-siRNA was loaded onto the mesoporous silica nanoparticles, and the optimized preparation achieved a rapamycin encapsulation efficiency of approximately 75%. In vitro, ultrasound-assisted AINAs reduced IL-23-induced reactive oxygen species accumulation and apoptosis in thyroid cells and suppressed CIITA and HLA-DR expression, antigen presentation, and Jurkat T-cell activation. In vivo, ultrasound enhanced the accumulation of AINAs in thyroid tissue. Treatment with AINAs plus ultrasound alleviated thyroid inflammation, reduced local CD3+ and CD4+ T-cell infiltration and serum thyroid autoantibody levels, and caused no apparent pathological injury to major organs. CONCLUSIONS: Ultrasound-responsive AINAs enabled the targeted delivery of CIITA-siRNA and rapamycin to thyroid tissue and showed anti-inflammatory and thyroid-protective effects in cellular and animal models of HT.