Li Ruomeng,Zhang Ting,Ren Dan,Zhu Hong,Xu Jiangxi,Xiao Lan
This study investigated the therapeutic potential and mechanism of Bushen Huoxue Acupuncture (BSHXA) against Alzheimer’s disease (AD) using integrated in vivo and in vitro approaches. In eight-month-old SAMP8 mice, BSHXA treatment significantly improved cognitive performance, alleviated hippocampal neuronal damage and neuroinflammation, and downregulated LAPTM5 expression. Complementary in vitro experiments in lipopolysaccharide (LPS)-stimulated BV2 microglia demonstrated that LAPTM5 knockdown reduced apoptosis, pathological protein accumulation, and pro-inflammatory M1 polarization. Through bioinformatic prediction and Co-IP assays, SMURF2 was identified as an E3 ubiquitin ligase directly interacting with LAPTM5 and promoting its ubiquitin-dependent degradation. SMURF2 overexpression in vitro reproduced protective effects similar to LAPTM5 knockdown. Importantly, in vivo knockdown of SMURF2 abolished the therapeutic benefits of BSHXA. Collectively, these findings demonstrate that BSHXA ameliorates AD progression by upregulating SMURF2, which promotes the ubiquitination and subsequent degradation of LAPTM5, thereby suppressing microglial M1 polarization, inhibiting neuroinflammatory responses, and attenuating AD pathologies. The SMURF2-LAPTM5 axis is established as a key mechanistic pathway underlying the neuroprotective effects of BSHXA. Graphical
Renal fibrosis is the major pathologic manifestation of chronic kidney disease (CKD). LIM and cysteine-rich domains 1 (LMCD1) is upregulated in the kidney tissue from patients with CKD and the transforming growth factor β1 (TGF-β1)–treated human renal tubular epithelial cell line human kidney 2 (HK-2) (Gene Expression Omnibus: GSE66494 and GSE23338). Previously, we have demonstrated that the knockdown of LMCD1 ameliorated renal fibrosis in mice by blocking the activation of the extracellular signal-regulated kinase pathway. In this study, we sought to further investigate whether LMCD1 affects TGF-β1–induced epithelial–mesenchymal transition (EMT) of kidney tubular epithelial cells and its potential role in the TGF-β1/Smad signaling pathway. First, we confirmed that LMCD1 expression was increased in the fibrotic kidneys of patients with CKD compared with that in normal kidneys and that LMCD1 was predominantly localized in the renal tubules. LMCD1 and mesenchymal markers were upregulated in obstructed kidney tissues of mice at 21 days after unilateral ureteral obstruction surgery compared with the tissues in sham mice. Next, we demonstrated that TGF-β1 significantly increased LMCD1 expression through Smad-mediated transcription in HK-2 cells in vitro. In turn, LMCD1 acted as a transcriptional coactivator of E2F transcription factor 1 to promote the transcription of TGF-β1 . Moreover, TGF-β1 increased the interaction between LMCD1 and Smad ubiquitination regulatory factor 2 (Smurf2) and accelerated Smurf2-mediated LMCD1 degradation via the ubiquitination system. The knockdown of LMCD1 inhibited TGF-β1–induced EMT in both HK-2 cells and unilateral ureteral obstruction mice. Our results indicate a positive feedback loop between TGF-β1 and LMCD1 for EMT induction in HK-2 cells and that Smurf2 acts as a negative regulator in this process by accelerating LMCD1 degradation.