Measuring the Effect of Histone Deacetylase Inhibitors (HDACi) on the Secretion and Activity of Alpha-1 Antitrypsin

Abstract

Alpha-1 antitrypsin deficiency (AATD) is a protein conformational disease with the most common cause being the Z-variant mutation in alpha-1 antitrypsin (Z-AAT). The misfolded conformation triggered by the Z-variant disrupts cellular proteostasis (protein folding) systems and fails to meet the endoplasmic reticulum (ER) export metrics, leading to decreased circulating AAT and deficient antiprotease activity in the plasma and lung. Here, we describe the methods for measuring the secretion and neutrophil elastase (NE) inhibition activity of AAT/Z-AAT, as well as the response to histone deacetylase inhibitor (HDACi), a major proteostasis modifier that impacts the secretion and function of AATD from the liver to plasma. These methods provide a platform for further therapeutic development of proteostasis regulators for AATD.

Keywords: Alpha-1 antitrypsin deficiency; Cellular proteostasis; Histone deacetylase inhibitor; Proteostasis regulators.

Figure 1

Western blot shows the secretion and NE inhibition activity of Z-AAT with or without SAHA treatment. (A) Secretion of WT-AAT or Z-AAT. M, mature fraction; I, immature fraction. (B) Secretion of Z-AAT under DMSO or SAHA condition. (C) NE inhibition activity of WT-AAT and Z-AAT with or without SAHA treatment. The band indicated by arrow is the AAT-NE complex. The band labeled by asterisk is the unbounded AAT. This figure is derived from reference (26).