Emo@KP MBs Modulates the TGF-β1/Smad Signaling Pathway by in situ Micro-Nano Conversion to Reduce Renal Inflammation and Fibrosis Caused by Unilateral Ureteral Obstruction

Jinxia Zhang,1,2,* Xinxin Xie,2,* Yuanjing Li,1,* Haonan Wang,2 Lijuan Zhang,1 Peiqi Shi,1 Jing Wei,1 Ling Zhang,1 Yingdong Lu,1 Ligang Cui,2 Xiaoning Liu,1 Xiaolong Liang2 1Department of Ultrasound, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, People’s Republic of China; 2Department of Ultrasound, Peking University Third Hospital, Beijing, 100191, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaoning Liu, Email liuxn_angel2023@163.com Xiaolong Liang, Email xiaolong_liang@bjmu.edu.cnIntroduction: Emodin alleviates renal interstitial fibrosis (RIF) and reduces inflammation by inhibiting the TGF-β 1/Smad pathway, thus improving CKD outcomes. However, its clinical use is limited due to poor solubility and side effects. This study developed a targeted drug delivery system using αKIM-1 modified microbubbles carrying Emodin to enhance accumulation in renal tissues with high KIM-1 expression.Methods: Emo@KP MBs were characterized by TEM and DLS, and their drug loading and encapsulation rates were measured by UV-VIS-NIR spectroscopy. Biocompatibility was assessed in vitro with HK-2 cells and in vivo via hematological and pathological markers. Contrast-enhanced ultrasound (CEUS) and fluorescence imaging were used for real-time visualization of treatment. Therapeutic experiments were performed on a unilateral ureteral obstruction (UUO) mouse model treated with Emo@KP MBs + US on days 1 and 3 post-surgery. Renal function, cytokine levels, and histological analysis were detected to evaluate therapeutic effects.Results: Emo@KP MBs exhibited spherical structures (2 ~ 4 μm) with good stability. Ultrasound targeted microbubble destruction (UTMD) enabled controlled release of Emodin. CEUS and fluorescence imaging showed enhanced drug accumulation in diseased kidneys. In the UUO + Emo@KP MBs/US group, renal function was improved, inflammatory cytokines (IL-1β, TNF-α) were decreased, and renal lesions and collagen deposition were reduced. Immunohistochemistry revealed the downregulation of TGF-β, Smad2/3, and α-SMA, and upregulation of E-cadherin.Conclusion: Emo@KP MBs enhanced drug delivery efficiency and therapeutic efficacy through αKIM-1 targeting and UTMD, while providing real-time imaging capabilities, suggesting good potential as a therapeutic approach to reduce renal inflammation and fibrosis in UUO.Keywords: unilateral ureteral obstruction, renal interstitial fibrosis, microbubbles, UTMD, Emodin, αKIM-1