bims-unfpre 2023-03-19 papers

bims-unfpre

Biomed News

on Unfolded protein response

Issue of 2023–03–19
eight papers selected by
Susan Logue, University of Manitoba

Antitumor T-cell function requires CPEB4-mediated adaptation to chronic endoplasmic reticulum stress.
ER proteostasis regulators cell-non-autonomously control sleep.
Bi-allelic mutation in SEC16B alters collagen trafficking and increases ER stress.
Endoplasmic reticulum stress in the intestinal epithelium initiates purine metabolite synthesis and promotes Th17 cell differentiation in the gut.
Targeting unfolded protein response using albumin-encapsulated nanoparticles attenuates temozolomide resistance in glioblastoma.
LINP1 represses unfolded protein response by directly inhibiting eIF2α phosphorylation to promote cutaneous squamous cell carcinoma.
CDNF rescues motor neurons in models of amyotrophic lateral sclerosis by targeting endoplasmic reticulum stress.
Palmitic acid-induced ferroptosis via CD36 activates ER stress to break calcium-iron balance in colon cancer cells.

EMBO J. 2023 Mar 15. e111494

Antitumor T-cell function requires CPEB4-mediated adaptation to chronic endoplasmic reticulum stress.

Marcos Fernández-Alfara, Annarita Sibilio, Judit Martin, Elsa Tusquets Uxó, Marina Malumbres, Victor Alcalde, Verónica Chanes, Adrià Cañellas-Socias, Sergio Palomo-Ponce, Eduard Batlle, Raúl Méndez.

  Tumor growth is influenced by a complex network of interactions between multiple cell types in the tumor microenvironment (TME). These constrained conditions trigger the endoplasmic reticulum (ER) stress response, which extensively reprograms mRNA translation. When uncontrolled over time, chronic ER stress impairs the antitumor effector function of CD8 T lymphocytes. How cells promote adaptation to chronic stress in the TME without the detrimental effects of the terminal unfolded protein response (UPR) is unknown. Here, we find that, in effector CD8 T lymphocytes, RNA-binding protein CPEB4 constitutes a new branch of the UPR that allows cells to adapt to sustained ER stress, yet remains decoupled from the terminal UPR. ER stress, induced during CD8 T-cell activation and effector function, triggers CPEB4 expression. CPEB4 then mediates chronic stress adaptation to maintain cellular fitness, allowing effector molecule production and cytotoxic activity. Accordingly, this branch of the UPR is required for the antitumor effector function of T lymphocytes, and its disruption in these cells exacerbates tumor growth.

Keywords:  CPEB; T lymphocytes; endoplasmic reticulum stress; mRNA translation; tumor microenvironment

DOI:  https://doi.org/10.15252/embj.2022111494
Cell Rep. 2023 Mar 15. pii: S2211-1247(23)00278-4. [Epub ahead of print]42(3): 112267

ER proteostasis regulators cell-non-autonomously control sleep.

Taizo Kawano, Mitsuaki Kashiwagi, Mika Kanuka, Chung-Kuan Chen, Shinnosuke Yasugaki, Sena Hatori, Shinichi Miyazaki, Kaeko Tanaka, Hidetoshi Fujita, Toshiro Nakajima, Masashi Yanagisawa, Yoshimi Nakagawa, Yu Hayashi.

  Sleep is regulated by peripheral tissues under fatigue. The molecular pathways in peripheral cells that trigger systemic sleep-related signals, however, are unclear. Here, a forward genetic screen in C. elegans identifies 3 genes that strongly affect sleep amount: sel-1, sel-11, and mars-1. sel-1 and sel-11 encode endoplasmic reticulum (ER)-associated degradation components, whereas mars-1 encodes methionyl-tRNA synthetase. We find that these machineries function in non-neuronal tissues and that the ER unfolded protein response components inositol-requiring enzyme 1 (IRE1)/XBP1 and protein kinase R-like ER kinase (PERK)/eukaryotic initiation factor-2α (eIF2α)/activating transcription factor-4 (ATF4) participate in non-neuronal sleep regulation, partly by reducing global translation. Neuronal epidermal growth factor receptor (EGFR) signaling is also required. Mouse studies suggest that this mechanism is conserved in mammals. Considering that prolonged wakefulness increases ER proteostasis stress in peripheral tissues, our results suggest that peripheral ER proteostasis factors control sleep homeostasis. Moreover, based on our results, peripheral tissues likely cope with ER stress not only by the well-established cell-autonomous mechanisms but also by promoting the individual's sleep.

Keywords:  C. elegans; CP: Cell biology; CP: Neuroscience; EGFR; cell non-autonomous; endoplasmic reticulum-associated degradation; proteostasis; sleep

DOI:  https://doi.org/10.1016/j.celrep.2023.112267
EMBO Mol Med. 2023 Mar 14. e16834

Bi-allelic mutation in SEC16B alters collagen trafficking and increases ER stress.

Ahmed El-Gazzar, Barbara Voraberger, Frank Rauch, Mario Mairhofer, Katy Schmidt, Brecht Guillemyn, Goran Mitulović, Veronika Reiterer, Margot Haun, Michaela M Mayr, Johannes A Mayr, Susanne Kimeswenger, Oliver Drews, Vrinda Saraff, Nick Shaw, Nadja Fratzl-Zelman, Sofie Symoens, Hesso Farhan, Wolfgang Högler.

  Osteogenesis imperfecta (OI) is a genetically and clinically heterogeneous disorder characterized by bone fragility and reduced bone mass generally caused by defects in type I collagen structure or defects in proteins interacting with collagen processing. We identified a homozygous missense mutation in SEC16B in a child with vertebral fractures, leg bowing, short stature, muscular hypotonia, and bone densitometric and histomorphometric features in keeping with OI with distinct ultrastructural features. In line with the putative function of SEC16B as a regulator of trafficking between the ER and the Golgi complex, we showed that patient fibroblasts accumulated type I procollagen in the ER and exhibited a general trafficking defect at the level of the ER. Consequently, patient fibroblasts exhibited ER stress, enhanced autophagosome formation, and higher levels of apoptosis. Transfection of wild-type SEC16B into patient cells rescued the collagen trafficking. Mechanistically, we show that the defect is a consequence of reduced SEC16B expression, rather than due to alterations in protein function. These data suggest SEC16B as a recessive candidate gene for OI.

Keywords:  SEC16B; autophagy; endoplasmic reticulum; osteogenesis imperfecta; type I collagen

DOI:  https://doi.org/10.15252/emmm.202216834
Immunity. 2023 Mar 07. pii: S1074-7613(23)00092-4. [Epub ahead of print]

Endoplasmic reticulum stress in the intestinal epithelium initiates purine metabolite synthesis and promotes Th17 cell differentiation in the gut.

Jinzhi Duan, Juan D Matute, Lukas W Unger, Thomas Hanley, Alexandra Schnell, Xi Lin, Niklas Krupka, Paul Griebel, Conner Lambden, Brandon Sit, Joep Grootjans, Michal Pyzik, Felix Sommer, Sina Kaiser, Maren Falk-Paulsen, Helmut Grasberger, John Y Kao, Tobias Fuhrer, Hai Li, Donggi Paik, Yunjin Lee, Samuel Refetoff, Jonathan N Glickman, Adrienne W Paton, Lynn Bry, James C Paton, Uwe Sauer, Andrew J Macpherson, Philip Rosenstiel, Vijay K Kuchroo, Matthew K Waldor, Jun R Huh, Arthur Kaser, Richard S Blumberg.

  Intestinal IL-17-producing T helper (Th17) cells are dependent on adherent microbes in the gut for their development. However, how microbial adherence to intestinal epithelial cells (IECs) promotes Th17 cell differentiation remains enigmatic. Here, we found that Th17 cell-inducing gut bacteria generated an unfolded protein response (UPR) in IECs. Furthermore, subtilase cytotoxin expression or genetic removal of X-box binding protein 1 (Xbp1) in IECs caused a UPR and increased Th17 cells, even in antibiotic-treated or germ-free conditions. Mechanistically, UPR activation in IECs enhanced their production of both reactive oxygen species (ROS) and purine metabolites. Treating mice with N-acetyl-cysteine or allopurinol to reduce ROS production and xanthine, respectively, decreased Th17 cells that were associated with an elevated UPR. Th17-related genes also correlated with ER stress and the UPR in humans with inflammatory bowel disease. Overall, we identify a mechanism of intestinal Th17 cell differentiation that emerges from an IEC-associated UPR.

Keywords:  Citrobacter rodentium; ROS signals; TH17 cells; commensal bacterial; epithelial endoplasmic reticulum stress; inflammatory bowel disease; purine metabolism

DOI:  https://doi.org/10.1016/j.immuni.2023.02.018
Br J Cancer. 2023 Mar 17.

Targeting unfolded protein response using albumin-encapsulated nanoparticles attenuates temozolomide resistance in glioblastoma.

Karrie Mei-Yee Kiang, Wanjun Tang, Qingchun Song, Jiaxin Liu, Ning Li, Tsz-Lung Lam, Ho Cheung Shum, Zhiyuan Zhu, Gilberto Ka-Kit Leung.

BACKGROUND: Chemoresistant cancer cells frequently exhibit a state of chronically activated endoplasmic reticulum (ER) stress. Engaged with ER stress, the unfolded protein response (UPR) is an adaptive reaction initiated by the accumulation of misfolded proteins. Protein disulfide isomerase (PDI) is a molecular chaperone known to be highly expressed in glioblastomas with acquired resistance to temozolomide (TMZ). We investigate whether therapeutic targeting of PDI provides a rationale to overcome chemoresistance.
METHODS: The activity of PDI was suppressed in glioblastoma cells using a small molecule inhibitor CCF642. Either single or combination treatment with TMZ was used. We prepared nanoformulation of CCF642 loaded in albumin as a drug carrier for orthotopic tumour model.
RESULTS: Inhibition of PDI significantly enhances the cytotoxic effect of TMZ on glioblastoma cells. More importantly, inhibition of PDI is able to sensitise glioblastoma cells that are initially resistant to TMZ treatment. Nanoformulation of CCF642 is well-tolerated and effective in suppressing tumour growth. It activates cell death-triggering UPR beyond repair and induces ER perturbations through the downregulation of PERK signalling. Combination treatment of TMZ with CCF642 significantly reduces tumour growth compared with either modality alone.
CONCLUSION: Our study demonstrates modulation of ER stress by targeting PDI as a promising therapeutic rationale to overcome chemoresistance.

DOI: https://doi.org/10.1038/s41416-023-02225-x
Exp Hematol Oncol. 2023 Mar 14. 12(1): 31

LINP1 represses unfolded protein response by directly inhibiting eIF2α phosphorylation to promote cutaneous squamous cell carcinoma.

Xiaoting Liang, Jieyu Liu, Xingyuan Liu, Yi Jin, Minna Xu, Zhenyu Han, Ke Wang, Chunting Zhang, Fei Zou, Liang Zhou.

   BACKGROUND: Endoplasmic reticulum stress (ER stress) may destroy endoplasmic reticulum homeostasis (ER homeostasis) and leads to programmable cell death. Unfolded protein response (UPR) originally stimulated by ER stress is critical for the survival of tumor cells through trying to re-establish ER homeostasis as an adaption to harsh microenvironment. However, mechanisms involving key regulators in modulating UPR remain underexplored.
METHODS: The expression of LINP1 in cutaneous squamous cell carcinoma (cSCC) tissues and cell lines was assessed. Subsequently, LINP1 was knocked out, knocked down or overexpressed in cSCC cells. CCK-8 assays, colony forming assays, transwell migration assays and invasiveness measurement by matrigel-coated transwell were performed to examine the role of LINP1 in cSCC development through gain-of-function and loss-of-function experiments. Transcriptomic sequencing (RNA-Seq) was conducted and indicated the key downstream signaling events regulated by LINP1 including UPR and apoptosis signaling. Furthermore, the direct interaction between LINP1 and eIF2α to modulate UPR and apoptosis was confirmed by RNA pulldown, RNA immunoprecipitation (RIP), ChIP-qPCR and in vitro phosphorylation assays.
RESULTS: In this study, LncRNA in non-homologous end joining pathway 1 (LINP1) was identified to be one of the top ten highest-expressed LncRNAs in cSCC, the second most common cancer in the world. Functional studies using in vitro and in vivo models revealed that LINP1 functions as an oncogene to promote cell proliferation, colony formation, migration and invasiveness while inhibiting cell apoptosis in cSCC. Transcriptomic sequencing after knockdown of LINP1 indicated LINP1 negatively regulates UPR-related pathways involving key effectors for activating UPR and the apoptosis following the prolonged UPR. Mechanistic study showed LINP1 physically interacts with eIF2α to inhibit its phosphorylation for avoiding unmitigated UPR. Loss of LINP1 followed by enhanced eIF2α phosphorylation led to overactivated UPR and induced DDIT3 expression, contributing to ER stress-induced apoptosis and suppression of cSCC development.
CONCLUSIONS: Our findings demonstrate a novel regulatory hierarchy of UPR by demonstrating LINP1 as a critical modulator for eIF2α phosphorylation and a suppressor of UPR-mediated apoptosis, which suggests a novel therapeutic target for cSCC treatment.

Keywords:  Apoptosis; Cutaneous squamous cell carcinoma; LINP1; Unfolded protein response; eIF2α

DOI:  https://doi.org/10.1186/s40164-023-00395-1
Brain. 2023 Mar 16. pii: awad087. [Epub ahead of print]

CDNF rescues motor neurons in models of amyotrophic lateral sclerosis by targeting endoplasmic reticulum stress.

Francesca De Lorenzo, Patrick Lüningschrör, Jinhan Nam, Liam Beckett, Federica Pilotto, Emilia Galli, Päivi Lindholm, Cora Rüdt von Collenberg, Simon Tii Mungwa, Sibylle Jablonka, Julia Kauder, Nadine Thau-Habermann, Susanne Petri, Dan Lindholm, Smita Saxena, Michael Sendtner, Mart Saarma, Merja H Voutilainen.

  Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects motor neurons (MNs) in the spinal cord, brainstem, and motor cortex, leading to paralysis and eventually to death within 3 to 5 years of symptom onset. To date, no cure or effective therapy is available. The role of chronic endoplasmic reticulum (ER) stress in the pathophysiology of amyotrophic lateral sclerosis, as well as a potential drug target, has received increasing attention. Here, we investigated the mode of action and therapeutic effect of the ER-resident protein cerebral dopamine neurotrophic factor (CDNF) in three preclinical models of amyotrophic lateral sclerosis, exhibiting different disease development and etiology: (i) the conditional choline acetyltransferase (ChAT)-tTA/TRE-hTDP43-M337V rat model previously described, (ii) the widely used SOD1-G93A mouse model, and (iii) a novel slow-progressive TDP43-M337V mouse model. To specifically analyse the ER stress response in MNs, we used three main methods: (i) primary culture of MNs derived from E13 days embryos, (ii) immunohistochemical analyses of spinal cord sections with ChAT as spinal MNs marker, and (iii) qPCR analyses of lumbar MNs isolated via laser microdissection. We show that intracerebroventricular administration of CDNF significantly halts the progression of the disease and improves motor behavior in TDP43-M337V and SOD1-G93A rodent models of amyotrophic lateral sclerosis. CDNF rescues motor neurons in vitro and in vivo from ER stress-associated cell death and its beneficial effect is independent of genetic disease etiology. Notably, CDNF regulates the unfolded protein response (UPR) initiated by transducers IRE1α, PERK, and ATF6, thereby enhancing MN survival. Thus, CDNF holds great promise for the design of new rational treatments for amyotrophic lateral sclerosis.

Keywords:  CDNF; ER stress; amyotrophic lateral sclerosis; motor neurons; unfolded protein response

DOI:  https://doi.org/10.1093/brain/awad087
FEBS J. 2023 Mar 12.

Palmitic acid-induced ferroptosis via CD36 activates ER stress to break calcium-iron balance in colon cancer cells.

Hao Kuang, Xuehua Sun, Ying Liu, Meng Tang, Yan Wei, Yingying Shi, Ruibin Li, Guohui Xiao, Jinlin Kang, Fen Wang, Jin Peng, Hui Xu, Fuxiang Zhou.

  Ferroptosis, featuring an iron-dependent peroxidation of lipids, is a novel form of programmed cell death that may hold great potential in cancer therapy. Our study found that palmitic acid (PA) inhibited colon cancer cell viability in vitro and in vivo, in conjunction with an accumulation of reactive oxygen species (ROS) and lipid peroxidation. The ferroptosis inhibitor Ferrostatin-1 but not Z-VAD-FMK (a pan-caspase inhibitor), Necrostatin-1 (a potent necroptosis inhibitor), or CQ (a potent inhibitor of autophagy), rescued the cell death phenotype induced by PA. Subsequently, we verified that PA induces ferroptotic cell death through excess iron as cell death was inhibited by iron chelator deferiprone (DFP), while it was exacerbated by a supplement of ferric ammonium citrate (FAC). Mechanistically, PA affects intracellular iron content by inducing endoplasmic reticulum (ER) stress leading to ER calcium release and regulating transferrin transport through increasing cytosolic calcium levels. Furthermore, we observed that cells with high expression of CD36 were more vulnerable to PA-induced ferroptosis. Altogether, our findings reveal that PA engages in anticancer properties by activating ER stress/ER calcium release/transferrin-dependent ferroptosis, and PA might serve as a compound to activate ferroptosis in colon cancer cells with high CD36 expression.

Keywords:  colon cancer，palmitic acid ，ferroptosis，CD36，ER stress

DOI:  https://doi.org/10.1111/febs.16772