Unspliced XBP1 Counteracts ß-Catenin to Inhibit Vascular Calcification.
Circ Res
; 130(2): 213-229, 2022 01 21.
Article
em En
| MEDLINE
| ID: mdl-34870453
ABSTRACT
BACKGROUND:
Vascular calcification is a prevalent complication in chronic kidney disease and contributes to increased cardiovascular morbidity and mortality. XBP1 (X-box binding protein 1), existing as the XBP1u (unspliced XBP1) and XBP1s (spliced XBP1) forms, is a key component of the endoplasmic reticulum stress involved in vascular diseases. However, whether XBP1u participates in the development of vascular calcification remains unclear.METHODS:
We aim to investigate the role of XBP1u in vascular calcification. XBP1u protein levels were reduced in high phosphate-induced calcified vascular smooth muscle cells, calcified aortas from mice with adenine diet-induced chronic renal failure, and calcified radial arteries from patients with chronic renal failure.RESULTS:
Inhibition of XBP1u rather than XBP1s upregulated in the expression of the osteogenic markers Runx2 (runt-related transcription factor 2) and Msx2 (msh homeobox 2), and exacerbated high phosphate-induced vascular smooth muscle cell calcification, as verified by calcium deposition and Alizarin red S staining. In contrast, XBP1u overexpression in high phosphate-induced vascular smooth muscle cells significantly inhibited osteogenic differentiation and calcification. Consistently, smooth muscle cell-specific XBP1 deficiency in mice markedly aggravated the adenine diet- and 5/6 nephrectomy-induced vascular calcification compared with that in the control littermates. Further interactome analysis revealed that XBP1u is bound directly to ß-catenin, a key regulator of vascular calcification, via amino acid (aa) 205-230 in its C-terminal degradation domain. XBP1u interacted with ß-catenin to promote its ubiquitin-proteasomal degradation and thus inhibited ß-catenin/TCF (T-cell factor)-mediated Runx2 and Msx2 transcription. Knockdown of ß-catenin abolished the effect of XBP1u deficiency on vascular smooth muscle cell calcification, suggesting a ß-catenin-mediated mechanism. Moreover, the degradation of ß-catenin promoted by XBP1u was independent of GSK-3ß (glycogen synthase kinase 3ß)-involved destruction complex.CONCLUSIONS:
Our study identified XBP1u as a novel endogenous inhibitor of vascular calcification by counteracting ß-catenin and promoting its ubiquitin-proteasomal degradation, which represents a new regulatory pathway of ß-catenin and a promising target for vascular calcification treatment.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Splicing de RNA
/
Beta Catenina
/
Calcificação Vascular
/
Proteína 1 de Ligação a X-Box
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
/
Male
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article