Dataset Information

FLI1 and ERG protein degradation is regulated via Cathepsin B lysosomal pathway in human dermal microvascular endothelial cells.

ABSTRACT:

Objectives

Friend leukemia integration 1 and erythroblast transformation-specific, important regulators of endothelial cell homeostasis, are reduced in microvascular endothelial cells in scleroderma patients, and their deficiency has been implicated in disease pathogenesis. The goal of this study was to identify the mechanisms involved in the protein turnover of friend leukemia integration 1 and erythroblast transformation-specific in microvascular endothelial cells.

Methods

The effects of lysosome and proteosome inhibitors on friend leukemia integration 1 and erythroblast transformation-specific levels were assessed by Western blotting and capillary morphogenesis. The effect of scleroderma and control sera on the levels of friend leukemia integration 1 and erythroblast transformation-specific was examined.

Results

The reduction in the protein levels of friend leukemia integration 1 and erythroblast transformation-specific in response to interferon α or Poly:(IC) was reversed by blocking either lysosomal (leupeptin and Cathepsin B inhibitor) or proteosomal degradation (MG132). MG132, leupeptin or CTSB-(i) also counteracted the anti-angiogenic effects of Poly:(IC) or interferon α. Scleroderma sera reduced protein levels of friend leukemia integration 1 and erythroblast transformation-specific in comparison to control sera. Treatment with CTSB(i) increased the levels of friend leukemia integration 1 and erythroblast transformation-specific in a majority of serum-treated samples.

Conclusions

Inhibition of cathepsin B was effective in reversing the reduction of friend leukemia integration 1 and erythroblast transformation-specific protein levels after treatment with interferon α or scleroderma sera, suggesting that targeting cathepsin B may have a beneficial effect in SSc vascular disease.

SUBMITTER: Mazzotta C

PROVIDER: S-EPMC7988617 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundBAMBI (BMP and Activin Membrane Bound Inhibitor) is considered to influence TGFβ and Wnt signaling, and thereby fibrosis. Surprisingly data on cell type-specific expression of BAMBI are not available. We therefore examined the localization, gene regulation, and protein turnover of BAMBI in kidneys.Methodology/principal findingsBy immunofluorescence microscopy and by mRNA expression, BAMBI is restricted to endothelial cells of the glomerular and some peritubular capillaries and of arteries and veins in both murine and human kidneys. TGFβ upregulated mRNA of BAMBI in murine glomerular endothelial cells (mGEC). LPS did not downregulate mRNA for BAMBI in mGEC or in HUVECs. BAMBI mRNA had a half-life of only 60 minutes and was stabilized by cycloheximide, indicating post-transcriptional regulation due to AU-rich elements, which we identified in the 3' untranslated sequence of both the human and murine BAMBI gene. BAMBI protein turnover was studied in HUVECs with BAMBI overexpression using a lentiviral system. Serum starvation as an inducer of autophagy caused marked BAMBI degradation, which could be totally prevented by inhibition of lysosomal and autolysosomal degradation with bafilomycin, and partially by inhibition of autophagy with 3-methyladenine, but not by proteasomal inhibitors. Rapamycin activates autophagy by inhibiting TOR, and resulted in BAMBI protein degradation. Both serum starvation and rapamycin increased the conversion of the autophagy marker LC3 from LC3-I to LC3-II and also enhanced co-staining for BAMBI and LC3 in autolysosomal vesicles.Conclusions/significance1. BAMBI localizes to endothelial cells in the kidney and to HUVECs. 2. BAMBI mRNA is regulated by post-transcriptional mechanisms. 3. BAMBI protein is regulated by lysosomal and autolysosomal degradation. The endothelial localization and the quick turnover of BAMBI may indicate novel, yet to be defined functions of this modulator for TGFβ and Wnt protein actions in the renal vascular endothelium in health and disease.