Format

Send to

Choose Destination
Infect Immun. 2017 Dec 19;86(1). pii: e00522-17. doi: 10.1128/IAI.00522-17. Print 2018 Jan.

Brucella abortus Promotes a Fibrotic Phenotype in Hepatic Stellate Cells, with Concomitant Activation of the Autophagy Pathway.

Author information

1
Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.
2
Instituto de Investigaciones Biotecnológicas, Dr. Rodolfo A. Ugalde (IIB-INTECH), CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina.
3
Center for NanoBiotechnology Research, Alabama State University, Montgomery, Alabama, USA.
4
Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina mdelpino@ffyb.uba.ar.

Abstract

The liver is frequently affected in patients with active brucellosis. The present study demonstrates that Brucella abortus infection induces the activation of the autophagic pathway in hepatic stellate cells to create a microenvironment that promotes a profibrogenic phenotype through the induction of transforming growth factor-β1 (TGF-β1), collagen deposition, and inhibition of matrix metalloproteinase-9 (MMP-9) secretion. Autophagy was revealed by upregulation of the LC3II/LC3I ratio and Beclin-1 expression as well as inhibition of p62 expression in infected cells. The above-described findings were dependent on the type IV secretion system (VirB) and the secreted BPE005 protein, which were partially corroborated using the pharmacological inhibitors wortmannin, a phosphatidyl inositol 3-kinase inhibitor, and leupeptin plus E64 (inhibitors of lysosomal proteases). Activation of the autophagic pathway in hepatic stellate cells during Brucella infection could have an important contribution to attenuating inflammatory hepatic injury by inducing fibrosis. However, with time, B. abortus infection induced Beclin-1 cleavage with concomitant cleavage of caspase-3, indicating the onset of apoptosis of LX-2 cells, as was confirmed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay and Hoechst staining. These results demonstrate that the cross talk of LX-2 cells and B. abortus induces autophagy and fibrosis with concomitant apoptosis of LX-2 cells, which may explain some potential mechanisms of liver damage observed in human brucellosis.

KEYWORDS:

Brucella; liver

PMID:
28993461
PMCID:
PMC5736806
DOI:
10.1128/IAI.00522-17
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center