bims-unfpre 2022-10-23 papers

bims-unfpre

Biomed News

on Unfolded protein response

Issue of 2022–10–23
eight papers selected by
Susan Logue, University of Manitoba

The unfolded protein response reverses the effects of glucose on lifespan in chemically-sterilized C. elegans.
Assessment of HDAC Inhibitor-Induced Endoplasmic Reticulum (ER) Stress.
Endoplasmic reticulum stress and unfolded protein accumulation correlate to seizure recurrence in focal cortical dysplasia patients.
Endoplasmic reticulum stress in melanoma pathogenesis and resistance.
Microvascular lung injury and endoplasmic reticulum stress in SLE-associated alveolar hemorrhage and pulmonary vasculitis.
Disruption of proteostasis causes IRE1 mediated reprogramming of alveolar epithelial cells.
Hypothalamic orexin prevents non-alcoholic steatohepatitis and hepatocellular carcinoma in obesity.
Protein synthesis inhibition and loss of homeostatic functions in astrocytes from an Alzheimer's disease mouse model: a role for ER-mitochondria interaction.

Nat Commun. 2022 Oct 19. 13(1): 5889

The unfolded protein response reverses the effects of glucose on lifespan in chemically-sterilized C. elegans.

Caroline Beaudoin-Chabot, Lei Wang, Cenk Celik, Aishah Tul-Firdaus Abdul Khalid, Subhash Thalappilly, Shiyi Xu, Jhee Hong Koh, Venus Wen Xuan Lim, Ann Don Low, Guillaume Thibault.

Metabolic diseases often share common traits, including accumulation of unfolded proteins in the endoplasmic reticulum (ER). Upon ER stress, the unfolded protein response (UPR) is activated to limit cellular damage which weakens with age. Here, we show that Caenorhabditis elegans fed a bacterial diet supplemented high glucose at day 5 of adulthood (HGD-5) extends their lifespan, whereas exposed at day 1 (HGD-1) experience shortened longevity. We observed a metabolic shift only in HGD-1, while glucose and infertility synergistically prolonged the lifespan of HGD-5, independently of DAF-16. Notably, we identified that UPR stress sensors ATF-6 and PEK-1 contributed to the longevity of HGD-5 worms, while ire-1 ablation drastically increased HGD-1 lifespan. Together, we postulate that HGD activates the otherwise quiescent UPR in aged worms to overcome ageing-related stress and restore ER homeostasis. In contrast, young animals subjected to HGD provokes unresolved ER stress, conversely leading to a detrimental stress response.

DOI: https://doi.org/10.1038/s41467-022-33630-0
Methods Mol Biol. 2023 ;2589 253-268

Assessment of HDAC Inhibitor-Induced Endoplasmic Reticulum (ER) Stress.

Melisa Halilovic, Lisa Marx-Blümel, Christian Marx, Katrin Buder, James F Beck, Jürgen Sonnemann.

  The endoplasmic reticulum (ER) is a multifunctional cell organelle which is important for the folding and processing of proteins. Different endogenous and exogenous factors can disturb the ER homeostasis, causing ER stress and activating the unfolded protein response (UPR) to remove misfolded proteins and aggregates. ER stress and the UPR are associated with several human diseases, such as diabetes, Alzheimer's or Parkinson's disease, and cancer. Histone deacetylase inhibitors (HDACi) are used to treat cancer and were shown to induce ER stress/to modulate the UPR, although the exact mechanism is not fully understood and needs further research. Several approaches to monitoring ER stress exist. Here we describe methods including qPCR, Western blot, transmission electron microscopy, and fluorescence microscopy to analyze changes in mRNA and protein expression levels as well as defects in ER structures after HDAC inhibitor-induced ER stress.

Keywords:  Electron microscopy; Endoplasmic reticulum (ER) stress; Fluorescence microscopy; HDAC inhibitor; HDACi; Unfolded protein response (UPR); Western blot; qPCR

DOI:  https://doi.org/10.1007/978-1-0716-2788-4_17
Cell Stress Chaperones. 2022 Oct 18.

Endoplasmic reticulum stress and unfolded protein accumulation correlate to seizure recurrence in focal cortical dysplasia patients.

Kishore Madhamanchi, Pradeep Madhamanchi, Sita Jayalakshmi, Manas Panigrahi, Anuja Patil, Prakash Babu Phanithi.

  Epileptic seizures occur due to an imbalance between excitatory and inhibitory neurosignals. The excitotoxic insults promote the accumulation of reactive oxygen species (ROS), unfolded proteins (UFP) aggregation, and sometimes even cell death. The epileptic brain samples in our study showed significant changes in the quantity of UFP accumulation. This part explored the efficiency of ER stress and autophagy responses at neutralizing the UFP using resected epileptic brain tissue samples. Meanwhile, we regularly observed these patients' post-surgical clinical data to find the recurrence of seizures. According to International League against Epilepsy (ILAE) suggestions, we classified the patients (n = 26) as class 1 (completely seizure-free), class 2 (less frequent seizures or auras), and class 3 (auras with < 3 seizures per year). The classification helped us understand the reason for variations in the UFP accumulation in patient samples. We have observed the protein levels of ER chaperone, glucose-regulated protein 78 kDa (GRP78/BiP), inositol-requiring enzyme 1α (IRE1α), X box-binding protein 1 s (XBP1s), eukaryotic translation initiation factor 2α (peIF2α), C/EBP homologous protein (CHOP), NADPH oxidase (NOX2), and autophagy proteins like BECLIN1, ATG 7, 12, 5, 16, p62, and LC3. Our results suggested that ER stress response limitation may contribute to seizure recurrence in epilepsy patients, particularly in classes 2 and 3. In addition, we have observed significant upregulation of ER stress-dependent apoptosis initiation factor CHOP in these patients. These results indicate that understanding the ER stress response pattern infers the possibility of post-surgical outcomes in focal cortical dysplasia (FCD) patients.

Keywords:  Autophagy; Clinical outcome; Endoplasmic reticulum stress; Focal cortical dysplasia (FCD); Oxidative stress; Unfolded protein response (UPR)

DOI:  https://doi.org/10.1007/s12192-022-01301-0
Biomed Pharmacother. 2022 Nov;pii: S0753-3322(22)01130-1. [Epub ahead of print]155 113741

Endoplasmic reticulum stress in melanoma pathogenesis and resistance.

Yi Kong, Jian Jiang, Yuqiong Huang, Li Li, Xin Liu, Zilin Jin, Fen Wei, Xinxin Liu, Song Zhang, Xiaoru Duan, Yonghui Zhang, Qingyi Tong, Hongxiang Chen.

  Melanoma is the most lethal skin cancer with rising incidence worldwide. Despite significant advances in target therapy and immunotherapy, low response rates and the development of drug resistance remain key clinical barriers affecting patient prognosis. The complex interplay between multiple signaling molecules and pathways has brought little understanding of melanoma pathogenesis and resistance. The genetic mutation and hypermetabolic environment of melanoma cells lead to increasing demands for protein synthesis and perturb proteostasis resulting in endoplasmic reticulum (ER) stress. Subsequently, three unfolded protein response (UPR) signaling branches, represented by IRE1α, PERK and ATF6, are activated to direct cell fate towards pro-survival or pro-apoptosis depending on the intensity and duration of ER stress. In this review, we summarize ER stress and UPR in melanoma cells and tumor-infiltrating immune cells along with the crosstalk among these pathways. We provide the latest advances in understanding melanoma pathogenesis and resistance and discuss the potential of targeting the ER stress or UPR process for melanoma therapy.

Keywords:  ATF6; ER stress; IRE1; Melanoma; PERK; UPR

DOI:  https://doi.org/10.1016/j.biopha.2022.113741
Am J Physiol Lung Cell Mol Physiol. 2022 Oct 18.

Microvascular lung injury and endoplasmic reticulum stress in SLE-associated alveolar hemorrhage and pulmonary vasculitis.

Haoyang Zhuang, Erin Hudson, Shuhong Han, Rawad Daniel Arja, Winnie Hui, Li Lu, Westley H Reeves.

  Human COPA mutations affecting retrograde Golgi-to-endoplasmic reticulum (ER) protein transport cause diffuse alveolar hemorrhage (DAH) and ER stress ("COPA syndrome"). SLE patients also can develop DAH. C57BL/6 (B6) mice with pristane-induced lupus develop monocyte-dependent DAH indistinguishable from human DAH, whereas BALB/c mice are resistant. We examined Copa and ER stress in pristane-induced lupus. Copa expression, ER stress, vascular injury, and apoptosis were assessed in mice and COPA was quantified in blood from SLE patients. Copa mRNA and protein expression were impaired in B6 mice with pristane-induced DAH, but not in pristane-treated BALB/c mice. An ER stress response (increased Hsp5a/BiP, Ddit3/CHOP, Eif2a, and spliced Xbp1) was seen in lung from pristane-treated B6, but not BALB/c, mice. Resistance of BALB/c mice to DAH was overcome by treating with low-dose thapsigargin plus pristane. CB6F1 mice did not develop DAH or ER stress, suggesting that susceptibility was recessive. Increased pulmonary expression of von Willebrand factor (Vwf), a marker of endothelial injury, and the chemokine Ccl2 in DAH suggested that pristane promotes lung microvascular injury and monocyte recruitment. Consistent with that possibility, lung endothelial cells and infiltrating bone marrow-derived cells from pristane-treated B6 mice expressed BiP and showed evidence of apoptosis (annexin-V and activated caspase-3 staining). COPA expression also was low in SLE patients with lung involvement. Pristane-induced DAH may be initiated by endothelial injury, resulting in ER stress, apoptosis of lung endothelial cells, and recruitment of myeloid cells that propagate lung injury. The pathogenesis of DAH in SLE and COPA syndrome may overlap.

Keywords:  alveolar hemorrhage; endoplasmic reticulum stress

DOI:  https://doi.org/10.1152/ajplung.00051.2022
Proc Natl Acad Sci U S A. 2022 Oct 25. 119(43): e2123187119

Disruption of proteostasis causes IRE1 mediated reprogramming of alveolar epithelial cells.

Jeremy Katzen, Luis Rodriguez, Yaniv Tomer, Apoorva Babu, Ming Zhao, Aditi Murthy, Paige Carson, Matthew Barrett, Maria C Basil, Justine Carl, John P Leach, Michael Morley, Matthew D McGraw, Surafel Mulugeta, Timothy Pelura, Glenn Rosen, Edward E Morrisey, Michael F Beers.

  Disruption of alveolar type 2 cell (AEC2) protein quality control has been implicated in chronic lung diseases, including pulmonary fibrosis (PF). We previously reported the in vivo modeling of a clinical surfactant protein C (SP-C) mutation that led to AEC2 endoplasmic reticulum (ER) stress and spontaneous lung fibrosis, providing proof of concept for disruption to proteostasis as a proximal driver of PF. Using two clinical SP-C mutation models, we have now discovered that AEC2s experiencing significant ER stress lose quintessential AEC2 features and develop a reprogrammed cell state that heretofore has been seen only as a response to lung injury. Using single-cell RNA sequencing in vivo and organoid-based modeling, we show that this state arises de novo from intrinsic AEC2 dysfunction. The cell-autonomous AEC2 reprogramming can be attenuated through inhibition of inositol-requiring enzyme 1 (IRE1α) signaling as the use of an IRE1α inhibitor reduced the development of the reprogrammed cell state and also diminished AEC2-driven recruitment of granulocytes, alveolitis, and lung injury. These findings identify AEC2 proteostasis, and specifically IRE1α signaling through its major product XBP-1, as a driver of a key AEC2 phenotypic change that has been identified in lung fibrosis.

Keywords:  ER stress; quality control; surfactant protein C; transitional cell; unfolded protein response

DOI:  https://doi.org/10.1073/pnas.2123187119
Cell Rep. 2022 Oct 18. pii: S2211-1247(22)01347-X. [Epub ahead of print]41(3): 111497

Hypothalamic orexin prevents non-alcoholic steatohepatitis and hepatocellular carcinoma in obesity.

Hiroshi Tsuneki, Takahiro Maeda, Shinjiro Takata, Masanori Sugiyama, Koyuki Otsuka, Hinako Ishizuka, Yasuhiro Onogi, Emi Tokai, Chiaki Koshida, Kanta Kon, Ichiro Takasaki, Takeru Hamashima, Masakiyo Sasahara, Assaf Rudich, Daisuke Koya, Takeshi Sakurai, Masashi Yanagisawa, Akihiro Yamanaka, Tsutomu Wada, Toshiyasu Sasaoka.

  Non-alcoholic steatohepatitis (NASH) occasionally occurs under obesity; however, factors modulating the natural history of fatty liver disease remain unknown. Since hypothalamic orexin that regulates physical activity and autonomic balance prevents obesity, we investigate its role in NASH development. Male orexin-deficient mice fed a high-fat diet (HFD) show severe obesity and progression of NASH with fibrosis in the liver. Hepatic fibrosis also develops in ovariectomized orexin-deficient females fed an HFD but not ovariectomized wild-type controls. Moreover, long-term HFD feeding causes hepatocellular carcinoma (HCC) in orexin-deficient mice. Intracerebroventricular injection of orexin A or pharmacogenetic activation of orexin neurons acutely activates hepatic mTOR-sXbp1 pathway to prevent endoplasmic reticulum (ER) stress, a NASH-causing factor. Daily supplementation of orexin A attenuates hepatic ER stress and inflammation in orexin-deficient mice fed an HFD, and autonomic ganglionic blocker suppresses the orexin actions. These results suggest that hypothalamic orexin is an essential factor for preventing NASH and associated HCC under obesity.

Keywords:  CP: Metabolism; autonomic nervous system; chronic inflammation; endoplasmic reticulum stress; liver cancer; non-alcoholic fatty liver disease; non-alcoholic steatohepatitis; obesity; orexin/hypocretin; physical inactivity

DOI:  https://doi.org/10.1016/j.celrep.2022.111497
Cell Death Dis. 2022 Oct 18. 13(10): 878

Protein synthesis inhibition and loss of homeostatic functions in astrocytes from an Alzheimer's disease mouse model: a role for ER-mitochondria interaction.

Laura Tapella, Giulia Dematteis, Marianna Moro, Beatrice Pistolato, Elisa Tonelli, Virginia Vita Vanella, Daniele Giustina, Aleida La Forgia, Elena Restelli, Elettra Barberis, Tito Cali, Marisa Brini, Salvatore Villani, Erika Del Grosso, Mariagrazia Grilli, Marcello Manfredi, Marco Corazzari, Ambra A Grolla, Armando A Genazzani, Dmitry Lim.

Deregulation of protein synthesis and ER stress/unfolded protein response (ER stress/UPR) have been reported in astrocytes. However, the relationships between protein synthesis deregulation and ER stress/UPR, as well as their role in the altered homeostatic support of Alzheimer's disease (AD) astrocytes remain poorly understood. Previously, we reported that in astrocytic cell lines from 3xTg-AD mice (3Tg-iAstro) protein synthesis was impaired and ER-mitochondria distance was reduced. Here we show that impaired protein synthesis in 3Tg-iAstro is associated with an increase of p-eIF2α and downregulation of GADD34. Although mRNA levels of ER stress/UPR markers were increased two-three-fold, we found neither activation of PERK nor downstream induction of ATF4 protein. Strikingly, the overexpression of a synthetic ER-mitochondrial linker (EML) resulted in a reduced protein synthesis and augmented p-eIF2α without any effect on ER stress/UPR marker genes. In vivo, in hippocampi of 3xTg-AD mice, reduced protein synthesis, increased p-eIF2α and downregulated GADD34 protein were found, while no increase of p-PERK or ATF4 proteins was observed, suggesting that in AD astrocytes, both in vitro and in vivo, phosphorylation of eIF2α and impairment of protein synthesis are PERK-independent. Next, we investigated the ability of 3xTg-AD astrocytes to support metabolism and function of other cells of the central nervous system. Astrocyte-conditioned medium (ACM) from 3Tg-iAstro cells significantly reduced protein synthesis rate in primary hippocampal neurons. When added as a part of pericyte/endothelial cell (EC)/astrocyte 3D co-culture, 3Tg-iAstro, but not WT-iAstro, severely impaired formation and ramification of tubules, the effect, replicated by EML overexpression in WT-iAstro cells. Finally, a chemical chaperone 4-phenylbutyric acid (4-PBA) rescued protein synthesis, p-eIF2α levels in 3Tg-iAstro cells and tubulogenesis in pericyte/EC/3Tg-iAstro co-culture. Collectively, our results suggest that a PERK-independent, p-eIF2α-associated impairment of protein synthesis compromises astrocytic homeostatic functions, and this may be caused by the altered ER-mitochondria interaction.

DOI: https://doi.org/10.1038/s41419-022-05324-4