Related Experiment Videos

Preventing and reversing the cellular consequences of Z alpha-1 antitrypsin accumulation by targeting s4A

Sam Alam1, Jicun Wang, Sabina Janciauskiene

  • 1Department of Medicine, University of Cambridge, Level 5, Box 157, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, UK.

Journal of Hepatology
|March 20, 2012
PubMed

Insights

Targeting strand 4a (s4A) with the 4M peptide prevents Z-alpha(1)-antitrypsin polymerization and accumulation in liver cells. This strategy restores plasma secretion and offers a potential treatment for Z-AT disease, including neonatal hepatitis and emphysema.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Hepatology

Background:

  • Alpha-1-antitrypsin (AT) Z variant polymerization causes liver disease and lung emphysema due to endoplasmic reticulum (ER) accumulation and secretory defects.
  • The Z variant's aggregation in hepatocytes leads to neonatal hepatitis and cirrhosis, while reduced plasma AT increases lung elastolysis risk.

Purpose of the Study:

  • To investigate targeting the s4A region of Z-AT as a therapeutic strategy to inhibit polymerization.
  • To evaluate the efficacy of novel peptides in preventing and reversing Z-AT aggregation.
  • To assess the impact of this strategy on Z-AT secretion and ER stress markers.

Main Methods:

  • HEK293 and HepG2 cells were transfected with Z-AT or M-AT.
  • Peptides (4M, 6M, 12M) were tested for their ability to prevent/reverse Z-AT polymerization and restore secretion using pulse-chase/immunoprecipitation, ELISA, and immunoblotting.
  • ER overload response was measured via RT-PCR (PERK, calnexin, RGS16) and ELISA (NF-κB, IL-6, IL-8).

Main Results:

  • Peptides, particularly 4M, effectively prevented Z-AT intracellular accumulation and reversed aggregation.
  • The 4M peptide significantly increased Z-AT secretion and elastase inhibitory activity.
  • 4M abrogated ER stress markers (PERK, NF-κB, IL-6, IL-8, RGS16, calnexin) without affecting cell viability or apoptosis.

Conclusions:

  • Targeting s4A with the 4M peptide is a novel strategy to inhibit Z-AT polymerization and its associated cellular damage.
  • This approach successfully restores Z-AT plasma concentrations and reduces ER stress.
  • These findings represent a significant advancement toward therapeutic interventions for Z-AT-related disorders.
Abstract

Related Concept Videos

Antiasthma Drugs: Leukotriene Modifiers01:19

Antiasthma Drugs: Leukotriene Modifiers

Leukotriene modifiers, or cysteinyl leukotriene receptor antagonists, are medications used to manage chronic asthma. These agents target specific inflammatory mediators produced during arachidonic acid metabolism, an essential process in generating inflammation in the body.
Leukotriene modifiers work through two distinct mechanisms:
Chronic Obstructive Pulmonary Disease II: Emphysema01:23

Chronic Obstructive Pulmonary Disease II: Emphysema

Emphysema, a major phenotype of chronic obstructive pulmonary disease (COPD), is characterized by irreversible destruction of alveolar walls and permanent enlargement of distal airspaces. Unlike chronic bronchitis, which primarily affects the airways, emphysema predominantly involves the lung parenchyma, where structural damage leads to airflow limitation.PathophysiologyIt most commonly results from prolonged exposure to cigarette smoke and other toxic gases, particularly cigarette smoke.
Cystic Fibrosis: Management01:24

Cystic Fibrosis: Management

Cystic fibrosis (CF) is an autosomal recessive disorder that predominantly affects individuals of Northern European descent, occurring at a rate of 1 in 3500. It is caused by a genetic mutation in a gene on chromosome 7, most commonly the ΔF508 mutation, that codes for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This results in thicker mucus secretions and obstruction pathologies in multiple organs, including the lungs and sinuses.
Sinus disease and chronic sinusitis...