scholarly journals Endoplasmic Reticulum Stress-Associated Neuronal Death and Innate Immune Response in Neurological Diseases

2022 ◽  
Vol 12 ◽  
Author(s):  
Mingming Shi ◽  
Yan Chai ◽  
Jianning Zhang ◽  
Xin Chen

Neuronal death and inflammatory response are two common pathological hallmarks of acute central nervous system injury and chronic degenerative disorders, both of which are closely related to cognitive and motor dysfunction associated with various neurological diseases. Neurological diseases are highly heterogeneous; however, they share a common pathogenesis, that is, the aberrant accumulation of misfolded/unfolded proteins within the endoplasmic reticulum (ER). Fortunately, the cell has intrinsic quality control mechanisms to maintain the proteostasis network, such as chaperone-mediated folding and ER-associated degradation. However, when these control mechanisms fail, misfolded/unfolded proteins accumulate in the ER lumen and contribute to ER stress. ER stress has been implicated in nearly all neurological diseases. ER stress initiates the unfolded protein response to restore proteostasis, and if the damage is irreversible, it elicits intracellular cascades of death and inflammation. With the growing appreciation of a functional association between ER stress and neurological diseases and with the improved understanding of the multiple underlying molecular mechanisms, pharmacological and genetic targeting of ER stress are beginning to emerge as therapeutic approaches for neurological diseases.

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Anna Walczak ◽  
Kinga Gradzik ◽  
Jacek Kabzinski ◽  
Karolina Przybylowska-Sygut ◽  
Ireneusz Majsterek

Cancer is the second most frequent cause of death worldwide. It is considered to be one of the most dangerous diseases, and there is still no effective treatment for many types of cancer. Since cancerous cells have a high proliferation rate, it is pivotal for their proper functioning to have the well-functioning protein machinery. Correct protein processing and folding are crucial to maintain tumor homeostasis. Endoplasmic reticulum (ER) stress is one of the leading factors that cause disturbances in these processes. It is induced by impaired function of the ER and accumulation of unfolded proteins. Induction of ER stress affects many molecular pathways that cause the unfolded protein response (UPR). This is the way in which cells can adapt to the new conditions, but when ER stress cannot be resolved, the UPR induces cell death. The molecular mechanisms of this double-edged sword process are involved in the transition of the UPR either in a cell protection mechanism or in apoptosis. However, this process remains poorly understood but seems to be crucial in the treatment of many diseases that are related to ER stress. Hence, understanding the ER stress response, especially in the aspect of pathological consequences of UPR, has the potential to allow us to develop novel therapies and new diagnostic and prognostic markers for cancer.


2020 ◽  
Vol 21 (6) ◽  
pp. 2108 ◽  
Author(s):  
Wioletta Rozpędek-Kamińska ◽  
Natalia Siwecka ◽  
Adam Wawrzynkiewicz ◽  
Radosław Wojtczak ◽  
Dariusz Pytel ◽  
...  

Higher prevalence of neurodegenerative diseases is strictly connected with progressive aging of the world population. Interestingly, a broad range of age-related, neurodegenerative diseases is characterized by a common pathological mechanism—accumulation of misfolded and unfolded proteins within the cells. Under certain circumstances, such protein aggregates may evoke endoplasmic reticulum (ER) stress conditions and subsequent activation of the unfolded protein response (UPR) signaling pathways via the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent manner. Under mild to moderate ER stress, UPR has a pro-adaptive role. However, severe or long-termed ER stress conditions directly evoke shift of the UPR toward its pro-apoptotic branch, which is considered to be a possible cause of neurodegeneration. To this day, there is no effective cure for Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), or prion disease. Currently available treatment approaches for these diseases are only symptomatic and cannot affect the disease progression. Treatment strategies, currently under detailed research, include inhibition of the PERK-dependent UPR signaling branches. The newest data have reported that the use of small-molecule inhibitors of the PERK-mediated signaling branches may contribute to the development of a novel, ground-breaking therapeutic approach for neurodegeneration. In this review, we critically describe all the aspects associated with such targeted therapy against neurodegenerative proteopathies.


Author(s):  
Toru Hosoi ◽  
Jun Nomura ◽  
Koichiro Ozawa ◽  
Akinori Nishi ◽  
Yasuyuki Nomura

AbstractThe endoplasmic reticulum (ER) is an organelle that plays a crucial role in protein quality control such as protein folding. Evidence to indicate the involvement of ER in maintaining cellular homeostasis is increasing. However, when cells are exposed to stressful conditions, which perturb ER function, unfolded proteins accumulate leading to ER stress. Cells then activate the unfolded protein response (UPR) to cope with this stressful condition. In the present review, we will discuss and summarize recent advances in research on the basic mechanisms of the UPR. We also discuss the possible involvement of ER stress in the pathogenesis of Alzheimer’s disease (AD). Potential therapeutic opportunities for diseases targeting ER stress is also described.


STEMedicine ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. e21
Author(s):  
Yanfei Wang ◽  
Zhigang Xu

The endoplasmic reticulum (ER) plays pivotal roles in coordinating protein biosynthesis and processing. Under ER stress, when excessive misfolded or unfolded proteins are accumulated in the ER, the unfolded protein response (UPR) is activated. The UPR blocks global protein synthesis while activates chaperone expression, eventually leading to the alleviation of ER stress. However, prolonged UPR induces cell death. ER stress has been associated with various types of diseases. Recently, increasing evidences suggest that ER stress and UPR are also involved in hearing loss. In the present review, we will discuss the role of ER stress in hereditary hearing loss as well as acquired hearing loss. Moreover, we will discuss the emerging ER stress-based treatment of hearing loss. Further investigations are warranted to understand the mechanisms in detail how ER stress contributes to hearing loss, which will help us develop better ER stress-related treatments.


2021 ◽  
Vol 69 (2) ◽  
pp. 309-315
Author(s):  
Ali Riza Koksal ◽  
George Nicholas Verne ◽  
QiQi Zhou

The ability of translated cellular proteins to perform their functions requires their proper folding after synthesis. The endoplasmic reticulum (ER) is responsible for coordinating protein folding and maturation. Infections, genetic mutations, environmental factors and many other conditions can lead to challenges to the ER known as ER stress. Altering ER homeostasis results in accumulation of misfolded or unfolded proteins. To eliminate this problem, a response is initiated by the cell called the unfolded protein response (UPR), which involves multiple signaling pathways. Prolonged ER stress or a dysregulated UPR can lead to premature apoptosis and an exaggerated inflammatory response. Following these discoveries, ER stress was shown to be related to several chronic diseases, such as diabetes mellitus, neurodegenerative disorders, fatty liver disease and inflammatory bowel disease that have not yet been clearly demonstrated pathophysiologically. Here, we review the field and present up-to-date information on the relationship between biological processing, ER stress, UPR, and several chronic diseases.


2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Afshin Samali ◽  
Una FitzGerald ◽  
Shane Deegan ◽  
Sanjeev Gupta

The endoplasmic reticulum (ER) is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the endoplasmic reticulum cause ER stress and activate a set of signaling pathways termed the Unfolded Protein Response (UPR). The UPR can promote cellular repair and sustained survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. Research into ER stress and the UPR continues to grow at a rapid rate as many new investigators are entering the field. There are also many researchers not working directly on ER stress, but who wish to determine whether this response is activated in the system they are studying: thus, it is important to list a standard set of criteria for monitoring UPR in different model systems. Here, we discuss approaches that can be used by researchers to plan and interpret experiments aimed at evaluating whether the UPR and related processes are activated. We would like to emphasize that no individual assay is guaranteed to be the most appropriate one in every situation and strongly recommend the use of multiple assays to verify UPR activation.


2008 ◽  
Vol 19 (10) ◽  
pp. 4404-4420 ◽  
Author(s):  
Renée Guérin ◽  
Geneviève Arseneault ◽  
Stéphane Dumont ◽  
Luis A. Rokeach

Stress conditions affecting the functions of the endoplasmic reticulum (ER) cause the accumulation of unfolded proteins. ER stress is counteracted by the unfolded-protein response (UPR). However, under prolonged stress the UPR initiates a proapoptotic response. Mounting evidence indicate that the ER chaperone calnexin is involved in apoptosis caused by ER stress. Here, we report that overexpression of calnexin in Schizosaccharomyces pombe induces cell death with apoptosis markers. Cell death was partially dependent on the Ire1p ER-stress transducer. Apoptotic death caused by calnexin overexpression required its transmembrane domain (TM), and involved sequences on either side of the ER membrane. Apoptotic death caused by tunicamycin was dramatically reduced in a strain expressing endogenous levels of calnexin lacking its TM and cytosolic tail. This demonstrates the involvement of calnexin in apoptosis triggered by ER stress. A genetic screen identified the S. pombe homologue of the human antiapoptotic protein HMGB1 as a suppressor of apoptotic death due to calnexin overexpression. Remarkably, overexpression of human calnexin in S. pombe also provoked apoptotic death. Our results argue for the conservation of the role of calnexin in apoptosis triggered by ER stress, and validate S. pombe as a model to elucidate the mechanisms of calnexin-mediated cell death.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jiancheng Xu ◽  
Qi Zhou ◽  
Wei Xu ◽  
Lu Cai

The endoplasmic reticulum (ER) is an organelle entrusted with lipid synthesis, calcium homeostasis, protein folding, and maturation. Perturbation of ER-associated functions results in an evolutionarily conserved cell stress response, the unfolded protein response (UPR) that is also called ER stress. ER stress is aimed initially at compensating for damage but can eventually trigger cell death if ER stress is excessive or prolonged. Now the ER stress has been associated with numerous diseases. For instance, our recent studies have demonstrated the important role of ER stress in diabetes-induced cardiac cell death. It is known that apoptosis has been considered to play a critical role in diabetic cardiomyopathy. Therefore, this paper will summarize the information from the literature and our own studies to focus on the pathological role of ER stress in the development of diabetic cardiomyopathy. Improved understanding of the molecular mechanisms underlying UPR activation and ER-initiated apoptosis in diabetic cardiomyopathy will provide us with new targets for drug discovery and therapeutic intervention.


2008 ◽  
Vol 295 (2) ◽  
pp. F323-F334 ◽  
Author(s):  
Masanori Kitamura

A number of pathophysiological insults lead to accumulation of unfolded proteins in the endoplasmic reticulum (ER) and cause ER stress. In response to accumulation of unfolded/misfolded proteins, cells adapt themselves to the stress condition via the unfolded protein response (UPR). For the cells, UPR is a double-edged sword. It triggers both prosurvival and proapoptotic signals. ER stress and UPR may, therefore, be involved in a diverse range of pathological situations. However, currently, information is limited regarding roles of ER stress and UPR in the renal pathophysiology. This review describes current knowledge on the relationship between ER stress and diseases and summarizes evidence for the link between ER stress/UPR and renal diseases.


2019 ◽  
Vol 20 (7) ◽  
pp. 1783 ◽  
Author(s):  
Takasugi ◽  
Hiraoka ◽  
Nakahara ◽  
Akiyama ◽  
Fujikawa ◽  
...  

The unfolded protein response (UPR) is activated by the accumulation of misfolded proteins in the endoplasmic reticulum (ER), which is called ER stress. ER stress sensors PERK, IRE1, and ATF6 play a central role in the initiation and regulation of the UPR; they inhibit novel protein synthesis and upregulate ER chaperones, such as protein disulfide isomerase, to remove unfolded proteins. However, when recovery from ER stress is difficult, the UPR pathway is activated to eliminate unhealthy cells. This signaling transition is the key event of many human diseases. However, the precise mechanisms are largely unknown. Intriguingly, reactive electrophilic species (RES), which exist in the environment or are produced through cellular metabolism, have been identified as a key player of this transition. In this review, we focused on the function of representative RES: nitric oxide (NO) as a gaseous RES, 4-hydroxynonenal (HNE) as a lipid RES, and methylmercury (MeHg) as an environmental organic compound RES, to outline the relationship between ER stress and RES. Modulation by RES might be a target for the development of next-generation therapy for ER stress-associated diseases.


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