scholarly journals Endoplasmic reticulum stress and pulmonary hypertension

2020 ◽  
Vol 10 (1) ◽  
pp. 204589401990012
Author(s):  
Yanan Hu ◽  
Wenhao Yang ◽  
Liang Xie ◽  
Tao Liu ◽  
Hanmin Liu ◽  
...  

Pulmonary hypertension is a fatal disease of which pulmonary vasculopathy is the main pathological feature resulting in the mean pulmonary arterial pressure higher than 25 mmHg. Moreover, pulmonary hypertension remains a tough problem with unclear molecular mechanisms. There have been dozens of studies about endoplasmic reticulum stress during the onset of pulmonary hypertension in patients, suggesting that endoplasmic reticulum stress may have a critical effect on the pathogenesis of pulmonary hypertension. The review aims to summarize the rationale to elucidate the role of endoplasmic reticulum stress in pulmonary hypertension. Started by reviewing the mechanisms responsible for the unfolded protein response following endoplasmic reticulum stress, the potential link between endoplasmic reticulum stress and pulmonary hypertension were introduced, and the contributions of endoplasmic reticulum stress to different vascular cells, mitochondria, and inflammation were described, and finally the potential therapies of attenuating endoplasmic reticulum stress for pulmonary hypertension were discussed.

2005 ◽  
Vol 391 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Daisuke Oikawa ◽  
Yukio Kimata ◽  
Masato Takeuchi ◽  
Kenji Kohno

The luminal domain of the type I transmembrane protein Ire1 senses endoplasmic reticulum stress by an undefined mechanism to up-regulate the signalling pathway for the unfolded protein response. Previously, we proposed that the luminal domain of yeast Ire1 is divided into five subregions, termed subregions I–V sequentially from the N-terminus. Ire1 lost activity when internal deletions of subregion II or IV were made. In the present paper, we show that partial proteolysis of a recombinant protein consisting of the Ire1 luminal domain suggests that subregions II–IV are tightly folded. We also show that a recombinant protein of subregions II–IV formed homodimers, and that this homodimer formation was impaired by an internal deletion of subregion IV. Furthermore, recombinant fragments of subregion IV exhibited a self-binding ability. Therefore, although its sequence is little conserved evolutionarily, subregion IV plays an essential role to promote Ire1 dimer formation.


2022 ◽  
Vol 16 (1) ◽  
pp. e0009192
Author(s):  
Michael Weingartner ◽  
Simon Stücheli ◽  
Fadi Jebbawi ◽  
Bruno Gottstein ◽  
Guido Beldi ◽  
...  

Background Echinococcus multilocularis causes alveolar echinococcosis (AE), a rising zoonotic disease in the northern hemisphere. Treatment of this fatal disease is limited to chemotherapy using benzimidazoles and surgical intervention, with frequent disease recurrence in cases without radical surgery. Elucidating the molecular mechanisms underlying E. multilocularis infections and host-parasite interactions ultimately aids developing novel therapeutic options. This study explored an involvement of unfolded protein response (UPR) and endoplasmic reticulum-stress (ERS) during E. multilocularis infection in mice. Methods E. multilocularis- and mock-infected C57BL/6 mice were subdivided into vehicle, albendazole (ABZ) and anti-programmed death ligand 1 (αPD-L1) treated groups. To mimic a chronic infection, treatments of mice started six weeks post i.p. infection and continued for another eight weeks. Liver tissue was then collected to examine inflammatory cytokines and the expression of UPR- and ERS-related genes. Results E. multilocularis infection led to an upregulation of UPR- and ERS-related proteins in the liver, including ATF6, CHOP, GRP78, ERp72, H6PD and calreticulin, whilst PERK and its target eIF2α were not affected, and IRE1α and ATF4 were downregulated. ABZ treatment in E. multilocularis infected mice reversed, or at least tended to reverse, these protein expression changes to levels seen in mock-infected mice. Furthermore, ABZ treatment reversed the elevated levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ in the liver of infected mice. Similar to ABZ, αPD-L1 immune-treatment tended to reverse the increased CHOP and decreased ATF4 and IRE1α expression levels. Conclusions and significance AE caused chronic inflammation, UPR activation and ERS in mice. The E. multilocularis-induced inflammation and consecutive ERS was ameliorated by ABZ and αPD-L1 treatment, indicating their effectiveness to inhibit parasite proliferation and downregulate its activity status. Neither ABZ nor αPD-L1 themselves affected UPR in control mice. Further research is needed to elucidate the link between inflammation, UPR and ERS, and if these pathways offer potential for improved therapies of patients with AE.


2005 ◽  
Vol 79 (11) ◽  
pp. 6890-6899 ◽  
Author(s):  
Jennifer A. Isler ◽  
Alison H. Skalet ◽  
James C. Alwine

ABSTRACT Viral infection causes stress to the endoplasmic reticulum. The response to endoplasmic reticulum stress, known as the unfolded protein response (UPR), is designed to eliminate misfolded proteins and allow the cell to recover by attenuating translation and upregulating the expression of chaperones, degradation factors, and factors that regulate the cell's metabolic and redox environment. Some consequences of the UPR (e.g., expression of chaperones and regulation of the metabolism and redox environment) may be advantageous to the viral infection; however, translational attenuation would not. Thus, viruses may induce mechanisms which modulate the UPR, maintaining beneficial aspects and suppressing deleterious aspects. We demonstrate that human cytomegalovirus (HCMV) infection induces the UPR but specifically regulates the three branches of UPR signaling, PKR-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1 (IRE-1), to favor viral replication. HCMV infection activated the eIF2α kinase PERK; however, the amount of phosphorylated eIF2α was limited and translation attenuation did not occur. Interestingly, translation of select mRNAs, which is dependent on eIF2α phosphorylation, did occur, including the transcription factor ATF4, which activates genes which may benefit the infection. The endoplasmic reticulum stress-induced activation of the transcription factor ATF6 was suppressed in HCMV-infected cells; however, specific chaperone genes, normally activated by ATF6, were activated by a virus-induced, ATF6-independent mechanism. Lastly, HCMV infection activated the IRE-1 pathway, as indicated by splicing of Xbp-1 mRNA. However, transcriptional activation of the XBP-1 target gene EDEM (ER degradation-enhancing α-mannosidase-like protein, a protein degradation factor) was inhibited. These results suggest that, although HCMV infection induces the unfolded protein response, it modifies the outcome to benefit viral replication.


Author(s):  
Robert Clarke ◽  
Ayesha N. Shajahan ◽  
Yue Wang ◽  
John J. Tyson ◽  
Rebecca B. Riggins ◽  
...  

AbstractLack of understanding of endocrine resistance remains one of the major challenges for breast cancer researchers, clinicians, and patients. Current reductionist approaches to understanding the molecular signaling driving resistance have offered mostly incremental progress over the past 10 years. As the field of systems biology has begun to mature, the approaches and network modeling tools being developed and applied therein offer a different way to think about how molecular signaling and the regulation of crucial cellular functions are integrated. To gain novel insights, we first describe some of the key challenges facing network modeling of endocrine resistance, many of which arise from the properties of the data spaces being studied. We then use activation of the unfolded protein response (UPR) following induction of endoplasmic reticulum stress in breast cancer cells by antiestrogens, to illustrate our approaches to computational modeling. Activation of UPR is a key determinant of cell fate decision-making and regulation of autophagy and apoptosis. These initial studies provide insight into a small subnetwork topology obtained using differential dependency network analysis and focused on the UPR gene XBP1. The XBP1 subnetwork topology incorporates BCAR3, BCL2, BIK, NF-κB, and other genes as nodes; the connecting edges represent the dependency structures among these nodes. As data from ongoing cellular and molecular studies become available, we will build detailed mathematical models of this XBP1-UPR network.


Sign in / Sign up

Export Citation Format

Share Document