scholarly journals Differences in Cellular Clearing Mechanisms of Aggregates of Two Subtypes of HLA-B27

2022 ◽  
Vol 12 ◽  
Author(s):  
Amit Kumar Thakur ◽  
Manni Luthra-Guptasarma

Ankylosing spondylitis (AS) belongs to a group of diseases, called spondyloarthropathies (SpA), that are strongly associated with the genetic marker HLA-B27. AS is characterized by inflammation of joints and primarily affects the spine. Over 160 subtypes of HLA-B27 are known, owing to high polymorphism. Some are strongly associated with disease (e.g., B*2704), whereas others are not (e.g., B*2709). Misfolding of HLA-B27 molecules [as dimers, or as high-molecular-weight (HMW) oligomers] is one of several hypotheses proposed to explain the link between HLA-B27 and AS. Our group has previously established the existence of HMW species of HLA-B27 in AS patients. Still, very little is known about the mechanisms underlying differences in pathogenic outcomes of different HLA-B27 subtypes. We conducted a proteomics-based evaluation of the differential disease association of HLA B*2704 and B*2709, using stable transfectants of genes encoding the two proteins. A clear difference was observed in protein clearance mechanisms: whereas unfolded protein response (UPR), autophagy, and aggresomes were involved in the degradation of B*2704, the endosome–lysosome machinery was primarily involved in B*2709 degradation. These differences offer insights into the differential disease association of B*2704 and B*2709.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Saeed Alizadeh ◽  
Ghasem Ghasempour ◽  
Elnaz Golestaneh ◽  
Yasaman Safian Isfahani ◽  
Arya Emami ◽  
...  

Background: Pregnancy is associated with oxidative stress that results in endoplasmic reticulum (ER) stress and unfolded protein response (UPR). Prolonged-unalleviated ER stress causes the activation of the autophagy pathway via UPR. Expression of genes encoding glucose-regulated protein 78 (GRP78) and BECLIN1 are induced in UPR and autophagy. Objectives: We studied the mRNA expression of the aforementioned genes in the liver and brain of Nulligravida versus saline and ethanol-treated pregnant rats. Methods: Control pregnant rats were orally treated with normal saline, and test animals received ethanol 250 mg/kg or resveratrol 120 mg/kg from day 1 to day 21 of gestation. Nulligravida rats treated by saline comprised the non-pregnant control group. On day 21, mRNAs encoding GRP78 and BECLIN1 were extracted from the liver and brain tissues and assessed using real-time PCR. Results: Our results showed that the level of transcripts encoding GRP78 and BECLIN1 was higher in the liver of pregnant rats compared to Nulligravida ones. Further, ethanol decreased the mRNA levels of GRP78 and BECLIN1 in the liver of pregnant rats, an effect that was reversed by resveratrol. Levels of GRP78 transcripts were decreased, and those of BECLIN1 remained unchanged in the brain of ethanol exposed pregnant rats. Conclusions: Levels of mRNAs for GRP78 and BECLIN1 are up-regulated during pregnancy. These levels are reduced in the liver of ethanol-treated rats, and resveratrol compensates these effects.


Sign in / Sign up

Export Citation Format

Share Document