bims-unfpre 2024-10-06 papers

bims-unfpre

Biomed News

on Unfolded protein response

Issue of 2024–10–06
eight papers selected by
Susan Logue, University of Manitoba

High-grade serous ovarian cancer development and anti-PD-1 resistance is driven by IRE1α activity in neutrophils.
AGR2 knockdown induces ER stress and mitochondria fission to facilitate pancreatic cancer cell death.
Roles of X-box binding protein 1 in liver pathogenesis.
The cytoplasmic-nuclear transport of DDX3X promotes immune-mediated liver injury in mice regulated by endoplasmic reticulum stress.
An Overview of Research Advances in Oncology Regarding the Transcription Factor ATF4.
G3BP isoforms differentially affect stress granule assembly and gene expression during cellular stress.
Increased Inflammation as well as Decreased Endoplasmic Reticulum Stress and Translation Differentiate Pancreatic Islets of Pre-symptomatic Stage 1 Type 1 Diabetes and Non-diabetic Cases.
KDELR2 is necessary for chronic obstructive pulmonary disease airway Mucin5AC hypersecretion via an IRE1α/XBP-1s-dependent mechanism.

Oncoimmunology. 2024 ;13(1): 2411070

High-grade serous ovarian cancer development and anti-PD-1 resistance is driven by IRE1α activity in neutrophils.

Alexander Emmanuelli, Camilla Salvagno, Sung-Min Hwang, Deepika Awasthi, Tito A Sandoval, Chang-Suk Chae, Jin-Gyu Cheong, Chen Tan, Takao Iwawaki, Juan R Cubillos-Ruiz.

  High-grade serious ovarian cancer (HGSOC) is an aggressive malignancy that remains refractory to current immunotherapies. While advanced stage disease has been extensively studied, the cellular and molecular mechanisms that promote early immune escape in HGSOC remain largely unexplored. Here, we report that primary HGSO tumors program neutrophils to inhibit T cell anti-tumor function by activating the endoplasmic reticulum (ER) stress sensor IRE1α. We found that intratumoral neutrophils exhibited overactivation of ER stress response markers compared with their counterparts at non-tumor sites. Selective deletion of IRE1α in neutrophils delayed primary ovarian tumor growth and extended the survival of mice with HGSOC by enabling early T cell-mediated tumor control. Notably, loss of IRE1α in neutrophils sensitized tumor-bearing mice to PD-1 blockade, inducing HGSOC regression and long-term survival in ~ 50% of the treated hosts. Hence, neutrophil-intrinsic IRE1α facilitates early adaptive immune escape in HGSOC and targeting this ER stress sensor might be used to unleash endogenous and immunotherapy-elicited immunity that controls metastatic disease.

Keywords:  ER stress; IRE1; PD-1 blockade; immunotherapy; neutrophils; ovarian cancer

DOI:  https://doi.org/10.1080/2162402X.2024.2411070
Biochim Biophys Acta Mol Cell Res. 2024 Sep 29. pii: S0167-4889(24)00197-6. [Epub ahead of print] 119854

AGR2 knockdown induces ER stress and mitochondria fission to facilitate pancreatic cancer cell death.

Philip Salu, Daniel Tuvin, Katie M Reindl.

  Anterior gradient 2 (AGR2) is often overexpressed in many human cancers, including pancreatic ductal adenocarcinoma (PDAC). Elevated AGR2 expression is known to play a critical role in tumor development, progression, and metastasis and positively correlates with poor patient survival. However, the relationship between AGR2 expression and tumor growth is not fully understood. Our study aims to investigate the impact of AGR2 knockdown on the survival of two pancreatic cancer cell lines, HPAF-II and PANC-1, that exhibit high AGR2 expression. This study revealed that the knockdown of AGR2 expression through an inducible shRNA-mediated approach reduced the proliferative ability and colony-forming potential of PDAC cells compared to scramble controls. Significantly, knocking down AGR2 led to the inhibition of multiple protein biosynthesis pathways and induced ER stress through unfolded protein response (UPR) activation. AGR2 knockdown induced ER stress and increased mitochondrial fission, while mitochondrial fusion remained unaffected. Ultimately, apoptotic cell death was heightened in AGR2 knockdown PDAC cells compared to the controls. Overall, these data reveal a new axis involving AGR2-ER stress-associated mitochondrial fission that could be targeted to improve PDAC patient outcomes.

Keywords:  Anterior gradient 2 (AGR2); ER stress; Mitochondria dysfunction; Pancreatic ductal adenocarcinoma (PDAC); Unfolded protein response (UPR)

DOI:  https://doi.org/10.1016/j.bbamcr.2024.119854
Clin Mol Hepatol. 2024 Oct 02.

Roles of X-box binding protein 1 in liver pathogenesis.

Jihoon Tak, Yun Seok Kim, Sang Geon Kim.

  The prevalence of drug-induced liver injury (DILI) and viral liver infections presents significant challenges in modern healthcare and contributes to considerable morbidity and mortality worldwide. Concurrently, metabolic dysfunction-associated fatty liver disease (MAFLD) has emerged as a major public health concern, reflecting the increasing rates of obesity and leading to more severe complications such as fibrosis and hepatocellular carcinoma. X-box binding protein 1 (XBP1) is a distinct transcription factor with a basic-region leucine zipper structure, whose activity is regulated by alternative splicing in response to disruptions in endoplasmic reticulum (ER) homeostasis and the unfolded protein response (UPR) activation. XBP1 interacts with a key signaling component of the highly conserved UPR and is critical in determining cell fate when responding to ER stress in liver diseases. This review aims to elucidate the emerging roles and molecular mechanisms of XBP1 in liver pathogenesis, focusing on its involvement in DILI, viral liver infections, MAFLD, fibrosis/cirrhosis, and liver cancer. Understanding the multifaceted functions of XBP1 in these liver diseases offers insights into potential therapeutic strategies to restore ER homeostasis and mitigate liver damage.

Keywords:  Drug-induced liver injury; Fibrosis/Cirrhosis; Hepatocellular carcinoma; Metabolic dysfunction-associated fatty liver disease; X-box binding protein 1

DOI:  https://doi.org/10.3350/cmh.2024.0441
Cell Death Dis. 2024 Sep 30. 15(9): 702

The cytoplasmic-nuclear transport of DDX3X promotes immune-mediated liver injury in mice regulated by endoplasmic reticulum stress.

Zihao Fan, Ling Xu, Yao Gao, Yaling Cao, Yuan Tian, Zhenzhen Pan, Linlin Wei, Sisi Chen, Xiangying Zhang, Mei Liu, Feng Ren.

Immune-mediated liver injury is a common characteristic of various liver diseases, including autoimmune and viral hepatitis. Here, we investigated the role of DEAD-box helicase 3, X-linked (DDX3X) in immune-mediated liver injury. Liver injury was induced in C57BL/6J mice via concanavalin A (Con A). DDX3X hepatocyte-specific knockout (DDX3XΔHep) mice and control (DDX3Xfl/fl) mice were utilized to investigate the role of DDX3X in liver injury. Primary hepatocytes were treated with tunicamycin (TM) to induce ER stress in vitro. The expression of DDX3X in patients with various liver diseases was evaluated. Hepatic DDX3X expression increased, and DDX3X translocated from the cytoplasm to the nucleus during Con A-induced liver injury. DDX3X deficiency ameliorated mouse liver injury and reduced ER stress in liver tissue. The inhibition of ER stress with 4-PBA significantly attenuated liver injury while decreasing DDX3X levels in liver tissue. However, the upregulation of hepatic DDX3X expression reversed Con A-induced liver injury and negated the protective effect of 4-PBA. Mechanistically, the nuclear translocation of DDX3X promoted ER stress-induced apoptosis through the transcriptional induction of CHOP. Moreover, DDX3X was elevated and translocated into the nucleus in patients with HBV-LF and AIH. Additionally, serum DDX3X levels markedly increased in patients with HBV-LF, and a consistent decrease in DDX3X was associated with a good prognosis. The cytoplasmic-to-nuclear translocation of DDX3X promotes ER stress-induced apoptosis, which is an obligatory step that drives hepatic necrosis and tissue damage. Notably, DDX3X is a potential therapeutic target for immune-mediated liver injury.

DOI: https://doi.org/10.1038/s41419-024-07076-9
Curr Drug Targets. 2024 Sep 30.

An Overview of Research Advances in Oncology Regarding the Transcription Factor ATF4.

Yulu Chen, Qi Gao, Dan Wang, Xun Zou, Xiuming Li, Jing Ji, Bin Liu.

  This review provides a comprehensive overview of the recent advancements in research on ATF4 (Activating Transcription Factor 4) within the field of oncology. As a crucial transcription factor, ATF4 has garnered increasing attention for its role in cancer research. The review begins with an exploration of the regulatory mechanisms of ATF4, including its transcriptional control, post-translational modifications, and interactions with other transcription factors. It then highlights key research findings on ATF4's involvement in various aspects of tumor biology, such as cell proliferation, differentiation, apoptosis and survival, invasion and metastasis, and the tumor microenvironment. Furthermore, the review discusses the potential of targeting ATF4 as a novel therapeutic strategy for cancer treatment. It also explores how ATF4's interactions with existing anticancer drugs could inform the development of more effective therapeutic agents. By elucidating the role of ATF4 in tumor biology and its potential clinical applications, this review aims to provide new insights and strategies for cancer treatment.

Keywords:  ATF4; ER stress.; malignant; targeted therapy; transcription factor; tumor

DOI:  https://doi.org/10.2174/0113894501328461240921062056
Mol Biol Cell. 2024 Oct 02. mbcE24020062

G3BP isoforms differentially affect stress granule assembly and gene expression during cellular stress.

José M Liboy-Lugo, Carla A Espinoza, Jessica Sheu-Gruttadauria, Jesslyn E Park, Albert Xu, Ziad Jowhar, Angela L Gao, José A Carmona-Negrón, Torsten Wittmann, Natalia Jura, Stephen N Floor.

Stress granules (SGs) are macromolecular assemblies that form under cellular stress. Formation of these membrane-less organelles is driven by the condensation of RNA and RNA-binding proteins such as G3BPs. G3BPs form SGs following stress-induced translational arrest. Three G3BP paralogs (G3BP1, G3BP2A, and G3BP2B) have been identified in vertebrates. However, the contribution of different G3BP paralogs to stress granule formation and gene expression changes is incompletely understood. Here, we probed the functions of G3BPs by identifying important residues for stress granule assembly at their N-terminal domain such as V11. This conserved amino acid is required for formation of the G3BP-Caprin-1 complex, hence promoting SG assembly. Total RNA sequencing and ribosome profiling revealed that a G3BPV11A mutant leads to changes in mRNA levels and ribosome engagement during the integrated stress response (ISR). Moreover, we found that G3BP2B preferentially forms stress granules and promotes changes in mRNA expression under endoplasmic reticulum (ER) stress. Furthermore, our work is a resource for researchers to study gene expression changes under cellular stress. Together, this work suggests that perturbing protein-protein interactions mediated by G3BPs affect stress granule assembly and gene expression during the ISR, and such functions are differentially regulated by G3BP paralogs under ER stress.

DOI: https://doi.org/10.1091/mbc.E24-02-0062
bioRxiv. 2024 Sep 19. pii: 2024.09.13.612933. [Epub ahead of print]

Increased Inflammation as well as Decreased Endoplasmic Reticulum Stress and Translation Differentiate Pancreatic Islets of Pre-symptomatic Stage 1 Type 1 Diabetes and Non-diabetic Cases.

Adam C Swensen, Paul D Piehowski, Jing Chen, X'avia Y Chan, Shane S Kelly, Vladislav A Petyuk, Ronald J Moore, Lith Nasif, Elizabeth A Butterworth, Mark A Atkinson, Rohit N Kulkarni, Martha Campbell-Thompson, Clayton E Mathews, Wei-Jun Qian.

Aims/hypothesis: Progression to type 1 diabetes (T1D) is associated with genetic factors, the presence of autoantibodies, and a decline in β cell insulin secretion in response to glucose. Very little is known regarding the molecular changes that occur in human insulin-secreting β-cells prior to the onset of T1D. Herein, we applied an unbiased proteomics approach to identify changes in proteins and potential mechanisms of islet dysfunction in islet autoantibody-positive organ donors with pre-symptomatic stage 1 T1D (HbA1c ≤ 6). We aimed to identify pathways in islets that are indicative of β-cell dysfunction.
Methods: Multiple islet sections were collected through laser microdissection of frozen pancreatic tissues of organ donors positive for islet autoantibodies (AAb+, n=5), compared to age/sex-matched nondiabetic controls (ND, n=5) obtained from the Network for Pancreatic Organ donors with Diabetes (nPOD). Islet sections were subjected to mass spectrometry-based proteomics and analyzed with label-free quantification followed by pathway and functional annotations.
Results: Analyses resulted in ∼4,500 proteins identified with low false discovery rate (FDR) <1%, with 2,165 proteins reliably quantified in every islet sample. We observed large inter-donor variations that presented a challenge for statistical analysis of proteome changes between donor groups. We therefore focused on the three multiple AAb+ cases (mAAb+) with high genetic risk and their three matched controls for a final statistical analysis. Approximately 10% of the proteins (n=202) were significantly different between mAAb+ cases versus ND. The significant alterations clustered around major functions for upregulation in the immune response and glycolysis, and downregulation in endoplasmic reticulum (ER) stress response as well as protein translation and synthesis. The observed proteome changes were further supported by several independent published datasets, including proteomics dataset from in vitro proinflammatory cytokine-treated human islets and single cell RNA-seq data sets from AAb+ cases.
Conclusion/interpretation: In-situ human islet proteome alterations at the stage 1 of AAb+ T1D centered around several major functional categories, including an expected increase in immune response genes (elevated antigen presentation / HLA), with decreases in protein synthesis and ER stress response, as well as compensatory metabolic response. The dataset serves as a proteomics resource for future studies on β cell changes during T1D progression and pathogenesis.

DOI: https://doi.org/10.1101/2024.09.13.612933
J Cell Mol Med. 2024 Oct;28(19): e70125

KDELR2 is necessary for chronic obstructive pulmonary disease airway Mucin5AC hypersecretion via an IRE1α/XBP-1s-dependent mechanism.

Xiaojuan Wu, Fawang Du, Aijie Zhang, Guoyue Zhang, Rui Xu, Xianzhi Du.

  Airway mucus hypersecretion, a crucial pathological feature of chronic obstructive pulmonary disease (COPD), contributes to the initiation, progression, and exacerbation of this disease. As a macromolecular mucin, the secretory behaviour of Mucin5AC (MUC5AC) is highly dependent on a series of modifying and folding processes that occur in the endoplasmic reticulum (ER). In this study, we focused on the ER quality control protein KDEL receptor (KDELR) and demonstrated that KDELR2 and MUC5AC were colocalized in the airway epithelium of COPD patients and COPD model rats. In addition, knockdown of KDELR2 markedly reduced the expression of MUC5AC both in vivo and in vitro and knockdown of ATF6 further decreased the levels of KDELR2. Furthermore, pretreatment with 4μ8C, an IRE1α inhibitor, led to a partial reduction in the expression of KDELR2 and MUC5AC both in vivo and in vitro, which indicated the involvement of IRE1α/XBP-1s in the upstream signalling cascade. Our study revealed that KDELR2 plays a crucial role in airway MUC5AC hypersecretion in COPD, which might be dependent on ATF6 and IRE1α/XBP-1s upstream signalling.

Keywords:  COPD; KDELR2; Mucin5AC; UPR; endoplasmic reticulum

DOI:  https://doi.org/10.1111/jcmm.70125