Alpha-1 antitrypsin deficient individuals have circulating extracellular vesicles with profibrogenic cargo

Abstract

Alpha-1 antitrypsin deficiency (AATD)-mediated liver disease is a toxic “gain-of-function” inflammation in the liver associated with intracellular retention of mutant alpha-1 antitrypsin. The clinical presentation of the disease includes fibrosis, cirrhosis and liver failure. However, the pathogenic mechanism of AATD-mediated liver disease is not well understood. Here, we investigated the role of plasma extracellular vesicles (EVs) in progression of AATD-mediated liver disease. EVs were isolated from plasma of AATD individuals with liver disease and healthy controls. Their cytokines and miRNA content were examined by multiplex assay and small RNA sequencing. We have found that AATD individuals have a distinct population of EVs with pathological cytokine and miRNA contents. Human hepatic stellate cells (HSCs) were then treated with EVs isolated from control or AATD plasma samples. When HSCs were cultured with AATD plasma derived-EVs, the expression of genes related to the development of fibrosis were significantly amplified compared to those treated with healthy control plasma EVs. In conclusion, AATD individuals have a distinct population of EVs with abnormal cytokine and miRNA contents and the capacity to activate HSCs and mediate fibrosis. Better understanding of the components which cause liver inflammation and fibrogenesis, leading to further liver injury, has the potential to lead to the development of new treatments or preventive strategies to prevent AATD-mediated liver disease.

Alpha-1 antitrypsin deficiency: A re-surfacing adult liver disorder

“…These include an alteration in lipid metabolism with more pronounced liver steatosis and decreased levels of serum triglycerides, as well as identification of extracellular vesicles with profibrogenic cargo in sera from Pi*ZZ individuals. 15,48…”

Correlation of Alpha-1 Antitrypsin Levels and Exosome Associated Neutrophil Elastase Endothelial Injury in Subjects with SARS-CoV2 Infection

“…Human lung microvascular endothelial cells (MVEC) from healthy donors [26], a gift from Dr. Andrew J. Bryant, were cultured on collagen in Vascular Cell Basal Medium supplemented with the VEGF Endothelial Cell Growth Kit (ATCC, Manassas, VA). Cells were treated with either 1×10 7 per well of quiescent exosome from HL-60 cells, activated (fMLP treated) exosomes from HL-60 cells [17], 34 nM of purified neutrophil elastase [27, 28] (Athens Research and Technology. Athens, GA), 34 nM of neutrophil elastase and purified alpha-1 antitrypsin (Grifols USA, Los Angeles, CA), or activated HL-60 exosomes and alpha-1 antitrypsin (34 nM) overnight before RNA was collected using Trizol.…”

“…Recently, a novel pathogenic entity of membrane-bound NE has been described wherein, activated neutrophils release NE associated with exosomes during degranulation which, are oriented in a configuration resistant to AAT [16]. Exosomes are a heterogeneous population of extracellular vesicles with an average diameter of around 150 nanometers which, have different biophysical functions in both physiological and pathological conditions [17]. Exosomes contain specific surface protein markers such as CD9, CD81, and CD63 [18].…”

“…Exosomes contain specific surface protein markers such as CD9, CD81, and CD63 [18]. Recently, studies have demonstrated that exosomes secreted from different cells transfer nucleic acids, proteins, or lipids to target cells, inducing changes in the recipient's functions and phenotypes [17]. The effects of exosomes on target cells differ depending on their cargo, and such functional heterogeneity can result in different responses in different target cell types [19].…”

“…Exosomes are a heterogeneous population of extracellular vesicles with an average diameter of around 150 nanometers which, have different biophysical functions in both physiological and pathological conditions [17]. Exosomes contain specific surface protein markers such as CD9, CD81, and CD63 [18].…”