bims-unfpre 2021-11-21 papers

bims-unfpre

Biomed News

on Unfolded protein response

Issue of 2021‒11‒21
ten papers selected by
Susan Logue
University of Manitoba

Tumor innervation is triggered by endoplasmic reticulum stress.
The unfolded protein response: An emerging therapeutic target for pancreatitis and pancreatic ductal adenocarcinoma.
Endoplasmic reticulum stress-induced release and binding of calreticulin from human ovarian cancer cells.
A novel endoplasmic stress mediator, Kelch domain containing 7B (KLHDC7B), increased Harakiri (HRK) in the SubAB-induced apoptosis signaling pathway.
Rescue of α-synuclein aggregation in Parkinson's patient neurons by synergistic enhancement of ER proteostasis and protein trafficking.
GRP78/BiP determines senescence evasion cell fate after cisplatin-based chemotherapy.
Echinacoside Upregulates Sirt1 to Suppress Endoplasmic Reticulum Stress and Inhibit Extracellular Matrix Degradation In Vitro and Ameliorates Osteoarthritis In Vivo.
Cell stress response impairs de novo NAD+ biosynthesis in the kidney.
Metabolically Activated Proteostasis Regulators Protect against Glutamate Toxicity by Activating NRF2.
NPTX1 mutations trigger endoplasmic reticulum stress and cause autosomal dominant cerebellar ataxia.

Oncogene. 2021 Nov 16.

Tumor innervation is triggered by endoplasmic reticulum stress.

Chen Chen Jiang, Mark Marsland, Yufang Wang, Amiee Dowdell, Edward Eden, Fangfang Gao, Sam Faulkner, Phillip Jobling, Xiang Li, Lihua Liu, Zhangyu He, Hubert Hondermarck.

Nerve infiltration in the tumor microenvironment is emerging as a promoter of cancer progression that could be targeted in therapies, but the mechanisms initiating tumor innervation remain to be elucidated. Here we report that endoplasmic reticulum (ER) stress in cancer cells is transmitted to neuronal cells, resulting in neurite outgrowth and tumor innervation. In vitro, the induction of ER stress in various human cancer cells resulted in the synthesis and release of the precursor for brain-derived neurotrophic factor (proBDNF) through a mechanism dependent on the transcription factor X-box binding protein 1 (XBP1). Cancer cell-released proBDNF was found to mediate the transmission of ER stress to neurons, resulting in the stimulation of neurite outgrowth. Next-generation sequencing indicated the increased expression of the Egl-9 family hypoxia inducible factor 3 (EGLN3) that was mediated by c-MYC and necessary to neurite outgrowth induced by proBDNF. In orthotopic tumor xenograft, ER stress stimulated XBP1 and proBDNF expression as well as tumor innervation. Anti-proBDNF antibody inhibited both tumor innervation and cancer progression induced by ER stress. Interestingly, the chemotherapeutic drug 5-Fluorouracil (5-FU) was found to induce ER stress and tumor innervation, and this effect was inhibited by anti-proBDNF antibody. Finally, in human tumors, cancer tissues with nerve infiltration expressed high XBP1 and proBDNF while EGLN3 was upregulated in infiltrated nerves. This study reveals that ER stress participates in tumor innervation through the release of proBDNF and that targeting this pathway could be used in future therapies.

DOI: https://doi.org/10.1038/s41388-021-02108-6
Pancreatology. 2021 Oct 28. pii: S1424-3903(21)00610-4. [Epub ahead of print]

The unfolded protein response: An emerging therapeutic target for pancreatitis and pancreatic ductal adenocarcinoma.

M Teresa Borrello, Mickenzie B Martin, Christopher L Pin.

  Pancreatitis is a debilitating disease involving inflammation and fibrosis of the exocrine pancreas. Recurrent or chronic forms of pancreatitis are a significant risk factor for pancreatic ductal adenocarcinoma. While genetic factors have been identified for both pathologies, environmental stresses play a large role in their etiology. All cells have adapted mechanisms to handle acute environmental stress that alters energy demands. A common pathway involved in the stress response involves endoplasmic reticulum stress and the unfolded protein response (UPR). While rapidly activated by many external stressors, in the pancreas the UPR plays a fundamental biological role, likely due to the high protein demands in acinar cells. Despite this, increased UPR activity is observed in response to acute injury or following exposure to risk factors associated with pancreatitis and pancreatic cancer. Studies in animal and cell cultures models show the importance of affecting the UPR in the context of both diseases, and inhibitors have been developed for several specific mediators of the UPR. Given the importance of the UPR to normal acinar cell function, efforts to affect the UPR in the context of disease must be able to specifically target pathology vs. physiology. In this review, we highlight the importance of the UPR to normal and pathological conditions of the exocrine pancreas. We discuss recent studies suggesting the UPR may be involved in the initiation and progression of pancreatitis and PDAC, as well as contributing to chemoresistance that occurs in pancreatic cancer. Finally, we discuss the potential of targeting the UPR for treatment.

Keywords:  (ATF6); (IRE1); (PDAC); (PERK); Activating transcription factor 6; ER stress Response; Inositol requiring enzyme 1; Integrated stress response; Pancreatic ductal adenocarcinoma; Pancreatitis; Protein kinase RNA-like ER kinase

DOI:  https://doi.org/10.1016/j.pan.2021.10.007
Cancer Immunol Immunother. 2021 Nov 20.

Endoplasmic reticulum stress-induced release and binding of calreticulin from human ovarian cancer cells.

Trefa M Abdullah, Jacqueline Whatmore, Edwin Bremer, Rimantas Slibinskas, Marek Michalak, Paul Eggleton.

  BACKGROUND: Calreticulin (CRT) is an endoplasmic reticulum (ER) chaperone, but can appear surface bound on cancers cells, including ovarian cancers (OC). We investigated at what stage of cell viability, CRT appeared associated with surface of human OC cells. CRT on pre-apoptotic tumour cells is thought to initiate their eradication via a process termed immunogenic cell death (ICD).METHODS: We treated OC cells with the chemotherapeutic-doxorubicin (DX) known to induce translocation of CRT to some tumour cell surfaces, with and without the ER stressor-thapsigargin (TG)-and/or an ER stress inhibitor-TUDCA. We monitored translocation/release of CRT in pre-apoptotic cells by flow cytometry, immunoblotting and ELISA. We investigated the difference in binding of FITC-CRT to pre-apoptotic, apoptotic and necrotic cells and the ability of extracellular CRT to generate immature dendritic cells from THP-1 monocytes.
RESULTS: Dx-treatment increased endogenously released CRT and extracellular FITC_CRT binding to human pre-apoptotic OC cells. DX and TG also promoted cell death in OC cells which also increased CRT release. These cellular responses were significantly inhibited by TUDCA, suggesting that ER stress is partially responsible for the changes in CRT cellular distribution. Extracellular CRT induces maturation of THP-1 towards a imDC phenotype, an important component of ICD.
CONCLUSION: Collectively, these cellular responses suggest that ER stress is partially responsible for the changes in CRT cellular distribution. ER-stress regulates in part the release and binding of CRT to human OC cells where it may play a role in ICD.

Keywords:  Doxorubicin; Tauroursodeoxycholic acid (TUDCA); Thapsigargin

DOI:  https://doi.org/10.1007/s00262-021-03072-6
Cell Death Discov. 2021 Nov 19. 7(1): 360

A novel endoplasmic stress mediator, Kelch domain containing 7B (KLHDC7B), increased Harakiri (HRK) in the SubAB-induced apoptosis signaling pathway.

Kinnosuke Yahiro, Kohei Ogura, Hiroyasu Tsutsuki, Sunao Iyoda, Makoto Ohnishi, Joel Moss.

Locus for Enterocyte Effacement (LEE)-positive Shiga-toxigenic Escherichia coli (STEC) contributes to many global foodborne diseases, with infection characterized by severe gastrointestinal symptoms, including bloody diarrhea. The incidence of LEE-negative STEC-mediated disease is also increasing globally. Subtilase cytotoxin (SubAB) is released by some LEE-negative STEC strains. It cleaves BiP, which is a chaperone protein located in the endoplasmic reticulum (ER), thereby causing apoptosis induced by ER stress. To date, the apoptotic signaling pathway mediated by SubAB has not been identified. In the current study, RNA-seq analysis showed that SubAB significantly induced the expression of Kelch domain containing 7B (KLHDC7B). We explored the role of KLHDC7B in the SubAB-induced apoptotic pathway. SubAB-induced KLHDC7B mRNA expression was increased after 12 h of incubation of toxin with HeLa cells. KLHDC7B expression was downregulated by knockdown of PKR-like endoplasmic reticulum kinase (PERK), CEBP homologous protein (CHOP), activating transcription factor 4 (ATF4), and CEBP β (CEBPB). KLHDC7B knockdown suppressed SubAB-stimulated CHOP expression, poly(ADP-ribose) polymerase (PARP) cleavage, and cytotoxicity. The over-expressed KLHDC7B was localized to the nucleus and cytosolic fractions. Next, we used RNA-seq to analyze the effect of KLHDC7B knockdown on apoptosis induced by SubAB, and found that the gene encoding for the pro-apoptotic Bcl-2 family protein, Harakiri (HRK), was upregulated in SubAB-treated control cells. However, this effect was not observed in SubAB-treated KLHDC7B-knockdown cells. Therefore, we identified the pathway through which SubAB-induced KLHDC7B regulates HRK expression, which is essential for apoptosis in toxin-mediated ER stress.

DOI: https://doi.org/10.1038/s41420-021-00753-0
Neuron. 2021 Nov 09. pii: S0896-6273(21)00862-X. [Epub ahead of print]

Rescue of α-synuclein aggregation in Parkinson's patient neurons by synergistic enhancement of ER proteostasis and protein trafficking.

Iva Stojkovska, Willayat Y Wani, Friederike Zunke, Nandkishore R Belur, Egor A Pavlenko, Nkatha Mwenda, Karan Sharma, Laetitia Francelle, Joseph R Mazzulli.

  Neurodegenerative disorders are characterized by a collapse in proteostasis, as shown by the accumulation of insoluble protein aggregates in the brain. Proteostasis involves a balance of protein synthesis, folding, trafficking, and degradation, but how aggregates perturb these pathways is unknown. Using Parkinson's disease (PD) patient midbrain cultures, we find that aggregated α-synuclein induces endoplasmic reticulum (ER) fragmentation and compromises ER protein folding capacity, leading to misfolding and aggregation of immature lysosomal β-glucocerebrosidase. Despite this, PD neurons fail to initiate the unfolded protein response, indicating perturbations in sensing or transducing protein misfolding signals in the ER. Small molecule enhancement of ER proteostasis machinery promotes β-glucocerebrosidase solubility, while simultaneous enhancement of trafficking improves ER morphology, lysosomal function, and reduces α-synuclein. Our studies suggest that aggregated α-synuclein perturbs the ability of neurons to respond to misfolded proteins in the ER, and that synergistic enhancement of multiple proteostasis branches may provide therapeutic benefit in PD.

Keywords:  ER stress; Parkinson's disease; alpha-synuclein; beta-glucocerebrosidase; iPSC-derived midbrain dopaminergic neurons; lysosomal dysfunction; protein aggregation

DOI:  https://doi.org/10.1016/j.neuron.2021.10.032
Sci Rep. 2021 Nov 17. 11(1): 22448

GRP78/BiP determines senescence evasion cell fate after cisplatin-based chemotherapy.

Zin Zin Ei, Kanuengnit Choochuay, Alisa Tubsuwan, Decha Pinkaew, Maneewan Suksomtip, Chanida Vinayanuwattikun, Pithi Chanvorachote, Preedakorn Chunhacha.

Cisplatin (CDDP) induces senescence characterized by senescence-associated secretory phenotypes (SASP) and the unfolded protein response (UPR). In this study, we investigated the proteins related to the UPR during the senescence cell fate. Strikingly, we found that one of the critical ER-resident proteins, GRP78/BiP, was significantly altered. Here we show that GRP78 levels differentially expressed depending on non-small lung cancer subtypes. GRP78 indeed regulates the evasion of senescence in adenocarcinoma A549 cells, in which the increased GRP78 levels enable them to re-proliferate after CDDP removal. Conversely, GRP78 is downregulated in the senescence H460 cells, making them lacking senescence evasion capability. We observed that the translational regulation critically contributed to the GRP78 protein levels in CDDP-induces senescence. Furthermore, the increased GRP78 level during senescence confers resistance to senolytic drug, Bortezomib, as observed by a twofold increase in IC50 in A549 senescence cells compared to the wild-type. This observation is also consistent in the cells that have undergone genetic manipulation by transfection with pcDNA3.1(+)-GRP78/BiP plasmids and pSpCas9(BB)-2A-Puro containing guide RNA sequence targeting GRP78 exon 3 to induce the overexpression and downregulation of GRP78 in H460 cells, respectively. Our findings reveal a unique role of GRP78 on the senescence evasion cell fate and senolytic drug resistance after cisplatin-based chemotherapy.

DOI: https://doi.org/10.1038/s41598-021-01540-8
Oxid Med Cell Longev. 2021 ;2021 3137066

Echinacoside Upregulates Sirt1 to Suppress Endoplasmic Reticulum Stress and Inhibit Extracellular Matrix Degradation In Vitro and Ameliorates Osteoarthritis In Vivo.

Zhen Lin, Cheng Teng, Libin Ni, Zhao Zhang, Xinlei Lu, Junsheng Lou, Libo Wang, Yuxin Wang, Wenhao Chen, Xiaolei Zhang, Zhongke Lin.

Background: Osteoarthritis (OA) is a progressive illness that destroys cartilage. Oxidative stress is a major contributor of OA, while endoplasmic reticulum (ER) stress is the key cellular damage under oxidative stress in chondrocytes. Echinacoside (ECH) is the main extract and active substance of Cistanche, with potent antioxidative stress (OS) properties, and currently under clinical trials in China. However, its function in OA is yet to be determined.Purpose: We aimed to explore the specific role of ECH in the occurrence and development of OA and its underlying mechanism in vivo and in vitro.
Methods: After the mice were anesthetized, the bilateral medial knee joint meniscus resection was performed to establish the DMM model. TBHP was used to induce oxidative stress to establish the OA model in chondrocytes in vitro. Western blot and RT-PCR were used to evaluate the level of ER stress-related biomarkers such as p-PERK/PERK, GRP78, ATF4, p-eIF2α/eIF2α, and CHOP and apoptosis-related proteins such as BAX, Bcl-2, and cleaved caspase-3. Meanwhile, we used SO staining, immunofluorescence, and immunohistochemical staining to evaluate the pharmacological effects of ECH in mice in vivo.
Results: We demonstrated the effectiveness of ECH in suppressing ER stress and restoring ECM metabolism in vitro. In particular, ECH was shown to suppress tert-Butyl hydroperoxide- (TBHP-) induced OS and subsequently lower the levels of p-PERK/PERK, GRP78, ATF4, p-eIF2α/eIF2α, and CHOP in vitro. Simultaneously, ECH reduced MMP13 and ADAMTS5 levels and promoted Aggrecan and Collagen II levels, suggesting ECM degradation suppression. Moreover, we showed that ECH mediates its cellular effects via upregulation of Sirt1. Lastly, we confirmed that ECH can protect against OA in mouse OA models.
Conclusion: In summary, our findings indicate that ECH can inhibit ER stress and ECM degradation by upregulating Sirt1 in mouse chondrocytes treated with TBHP. It can also prevent OA development in vivo.

DOI: https://doi.org/10.1155/2021/3137066
JCI Insight. 2021 Nov 18. pii: e153019. [Epub ahead of print]

Cell stress response impairs de novo NAD+ biosynthesis in the kidney.

Yohan Bignon, Anna Rinaldi, Zahia Nadour, Virginie Poindessous, Ivan Nemazanyy, Olivia Lenoir, Baptiste Fohlen, Pierre Weill-Raynal, Alexandre Hertig, Alexandre Karras, Pierre Galichon, Maarten Naesens, Dany Anglicheau, Pietro E Cippà, Nicolas Pallet.

  The biosynthetic routes leading to de novo Nicotinamine Adenine Dinucleotide (NAD+) production are involved in acute kidney injury (AKI) with a critical role for Quinolinate Phosphoribosyl Transferase (QPRT), a bottleneck enzyme of de novo NAD+ biosynthesis. However, the molecular mechanisms determining reduced QPRT in AKI, and the role of impaired NAD+ biosynthesis in the progression to chronic kidney disease (CKD) are unknown. We demonstrate that a high urinary quinolinate to tryptophan ratio, an indirect indicator of impaired QPRT activity and reduced de novo NAD+ biosynthesis in the kidney, is a clinically applicable early marker of AKI after cardiopulmonary bypass, and is predictive of progression to chronic kidney disease (CKD) in kidney transplant recipients. We also provide evidence that the Endoplasmic Reticulum (ER) stress response impairs de novo NAD+ biosynthesis by repressing QPRT transcription. In conclusion, NAD+ biosynthesis impairment is an early event in AKI embedded with the ER stress response, and persistent reduction of QPRT expression is associated with AKI to CKD progression. This defines non-invasive metabolic biomarkers of kidney injury with prognostic and therapeutic implications.

Keywords:  Bioenergetics; Cell stress; Diagnostics; Metabolism; Nephrology

DOI:  https://doi.org/10.1172/jci.insight.153019
ACS Chem Biol. 2021 Nov 19.

Metabolically Activated Proteostasis Regulators Protect against Glutamate Toxicity by Activating NRF2.

Jessica D Rosarda, Kelsey R Baron, Kayla Nutsch, Gabriel M Kline, Caroline Stanton, Jeffery W Kelly, Michael J Bollong, R Luke Wiseman.

The extracellular accumulation of glutamate is a pathologic hallmark of numerous neurodegenerative diseases including ischemic stroke and Alzheimer's disease. At high extracellular concentrations, glutamate causes neuronal damage by promoting oxidative stress, which can lead to cellular death. This has led to significant interest in developing pharmacologic approaches to mitigate the oxidative toxicity caused by high levels of glutamate. Here, we show that the small molecule proteostasis regulator AA147 protects against glutamate-induced cell death in a neuronal-derived cell culture model. While originally developed as an activator of the activating transcription factor 6 (ATF6) arm of the unfolded protein response, this AA147-dependent protection against glutamate toxicity is primarily mediated through activation of the NRF2-regulated oxidative stress response. We demonstrate that AA147 activates NRF2 selectively in neuronal-derived cells through a mechanism involving metabolic activation to a reactive electrophile and covalent modification of KEAP1─a mechanism analogous to that involved in the AA147-dependent activation of ATF6. These results define the potential for AA147 to protect against glutamate-induced oxidative toxicity and highlight the potential for metabolically activated proteostasis regulators like AA147 to activate both protective ATF6 and NRF2 stress-responsive signaling pathways to mitigate oxidative damage associated with diverse neurologic diseases.

DOI: https://doi.org/10.1021/acschembio.1c00810
Brain. 2021 Nov 11. pii: awab407. [Epub ahead of print]

NPTX1 mutations trigger endoplasmic reticulum stress and cause autosomal dominant cerebellar ataxia.

Marie Coutelier, Maxime Jacoupy, Alexandre Janer, Flore Renaud, Nicolas Auger, Ganapathi-Varma Saripella, François Ancien, Fabrizio Pucci, Marianne Rooman, Dimitri Gilis, Roxanne Larivière, Nicolas Sgarioto, Rémi Valter, Léna Guillot-Noel, Isabelle Le Ber, Sabrina Sayah, Perrine Charles, Astrid Nümann, Martje G Pauly, Christoph Helmchen, Natalie Deininger, Tobias B Haack, Bernard Brais, Alexis Brice, David-Alexandre Trégouët, Khalid H El Hachimi, Eric A Shoubridge, Alexandra Durr, Giovanni Stevanin.

  With more than forty causative genes identified so far, autosomal dominant cerebellar ataxias exhibit a remarkable genetic heterogeneity. Yet, half the patients are lacking a molecular diagnosis. In a large family with nine sampled affected members, we performed exome sequencing combined with whole-genome linkage analysis. We identified a missense variant in NPTX1, NM_002522.3: c.1165G>A: p.G389R, segregating with the phenotype. Further investigations with whole exome sequencing and an amplicon-based panel identified four additional unrelated families segregating the same variant, for whom a common founder effect could be excluded. A second missense variant, NM_002522.3: c.980A>G: p.E327G, was identified in a fifth familial case. The NPTX1-associated phenotype consists of a late-onset, slowly progressive, cerebellar ataxia, with downbeat nystagmus, cognitive impairment reminiscent of cerebellar cognitive affective syndrome, myoclonic tremor and mild cerebellar vermian atrophy on brain imaging. NPTX1 encodes the neuronal pentraxin 1, a secreted protein with various cellular and synaptic functions. Both variants affect conserved amino-acid residues and are extremely rare or absent from public databases. In COS7 cells, overexpression of both neuronal pentraxin 1 variants altered endoplasmic reticulum morphology and induced ATF6-mediated endoplasmic reticulum stress, associated with cytotoxicity. In addition, the p. E327G variant abolished neuronal pentraxin 1 secretion, as well as its capacity to form a high molecular weight complex with the wild-type protein. Co-immunoprecipitation experiments coupled with mass spectrometry analysis demonstrated abnormal interactions of this variant with the cytoskeleton. In agreement with these observations, in silico modelling of the neuronal pentraxin 1 complex evidenced a destabilizing effect for the p. E327G substitution, located at the interface between monomers. On the contrary, the p. G389 residue, located at the protein surface, had no predictable effect on the complex stability. Our results establish NPTX1 as a new causative gene in autosomal dominant cerebellar ataxias. We suggest that variants in NPTX1 can lead to cerebellar ataxia due to endoplasmic reticulum stress, mediated by ATF6, and associated to a destabilization of NP1 polymers in a dominant-negative manner for one of the variants.

Keywords:  autosomal dominant cerebellar ataxias; endoplasmic reticulum stress; neuronal pentraxin 1

DOI:  https://doi.org/10.1093/brain/awab407