bims-unfpre 2024-12-22 papers

bims-unfpre

Biomed News

on Unfolded protein response

Issue of 2024–12–22
thirteen papers selected by
Susan Logue, University of Manitoba

Endoplasmic Reticulum Stress Induces ROS Production and Activates NLRP3 Inflammasome Via the PERK-CHOP Signaling Pathway in Dry Eye Disease.
An endoplasmic reticulum stress related signature for clinically predicting prognosis of breast cancer patients.
Dynamic modulation of IRE1α-XBP1 signaling by adenovirus.
Multiple Myeloma Cells with Increased Proteasomal and ER Stress Are Hypersensitive to ATX-101, an Experimental Peptide Drug Targeting PCNA.
MiR-378 exaggerates angiogenesis and bone erosion in collagen-induced arthritis mice by regulating endoplasmic reticulum stress.
Temperature perception by ER UPR promotes preventive innate immunity and longevity.
NIR-715 photodynamic therapy induces immunogenic cancer cell death by enhancing the endoplasmic reticulum stress response.
Emerging role of IRE1α in vascular diseases.
Mitochondrial unfolded protein response-dependent β-catenin signaling promotes neuroendocrine prostate cancer.
GALNTL5, which is restricted to mouse spermatids, impairs endoplasmic reticulum (ER) function through direct interaction with ER chaperone proteins.
Advanced PROTAC and Quantitative Proteomics Strategy Reveals Bax Inhibitor-1 as a Critical Target of Icaritin in Burkitt Lymphoma.
Dual functions of silibinin in attenuating aortic dissection via regulating iron homeostasis and endoplasmic reticulum stress against ferroptosis.
KIRA6 is an Effective and Versatile Mast Cell Inhibitor of IgE-mediated Activation.

Invest Ophthalmol Vis Sci. 2024 Dec 02. 65(14): 34

Endoplasmic Reticulum Stress Induces ROS Production and Activates NLRP3 Inflammasome Via the PERK-CHOP Signaling Pathway in Dry Eye Disease.

Zhiwei Zha, Decheng Xiao, Zihao Liu, Fangli Peng, Xunjie Shang, Zhenzhen Sun, Yang Liu, Wei Chen.

Purpose: The purpose of this study was to investigate the potential roles of endoplasmic reticulum (ER) stress in the development of dry eye disease (DED).
Methods: Single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database, derived from corneal tissues of a dry eye mouse model, was processed using the Seurat R program. The results were validated using a scopolamine-induced dry eye mouse model and a hyperosmotic-induced cell model involving primary human corneal epithelial cells (HCECs) and immortalized human corneal epithelial (HCE-2) cells. The HCE-2 cells were treated with 4-phenylbutyric acid (4-PBA) or tunicamycin (TM) to modulate ER stress. TXNIP and PERK knockdown were performed by siRNA transfection. Immunofluorescence, Western blotting, and real-time PCR were used to assess oxidative stress, ER stress, unfolded protein response (UPR) marker proteins, and TXNIP/NLRP3 axis activation.
Results: The analysis of scRNAseq data shows an increase in the ER stress marker GRP78, and the activation of the PERK-CHOP of UPR in DED mouse. These findings were confirmed both in vivo and in vitro. Additionally, HCE-2 cells treated with 4-PBA or TM showed significant effects on the production of reactive oxygen species (ROS) and the activation of the TXNIP/NLRP3-IL1β signaling pathway. Furthermore, siRNA knockdown of PERK or TXNIP, which alleviated the TXNIP/NLRP3-IL1β signaling axis, showed protective effects on HCECs.
Conclusions: This study explores the role of ER stress-induced oxidative stress and NLRP3-IL-1β mediated inflammation in DED, and highlights the therapeutic potential of PERK-CHOP axis and TXNIP in the treatment of DED.

DOI: https://doi.org/10.1167/iovs.65.14.34
Hum Mol Genet. 2024 Dec 04. pii: ddae170. [Epub ahead of print]

An endoplasmic reticulum stress related signature for clinically predicting prognosis of breast cancer patients.

Enqi Qiao, Jiayi Ye, Kaiming Huang.

   BACKGROUND: Endoplasmic Reticulum Stress (ER stress) was an important event in the development of breast cancer. We aimed to predict prognosis based on ER stress related key genes.
METHODS: Data of the RNA-seq and clinical information of breast cancer cases were downloaded from the TCGA database. A total of 4 genes related with ER stress was identified by the univariate Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO)-penalized Cox proportional hazards regression analysis. The predictive ability of the ER stress model was evaluated by utilizing Kaplan-Meier curves and time-dependent receiver operating characteristic (ROC) curves. Moreover, we verified 4 genes expression and its relationship with clinical breast cancer cases in real-world.
RESULTS: 4 genes including RNF186, BCAP31, SERPINA1, TAPBP were identified as a prognostic risk score model. Based on that, we found patients of breast cancer had a better survival with low-risk score. And also, ER stress model showed a good diagnostic efficacy with AUC curve. The risk score was significantly associated with patients' age, T stage and clinical stage. A nomogram was constructed to estimate individual survival. Further GO and KEGG analysis showed our model was related with immune infiltration. Patients of breast cancer with high-risk scores were usually accompanied with poor immune infiltration. It was predicted that high risk group was more sensitive to Vinorelbine, Docetaxel and Cisplatin. At last, we verified the expression of four signature genes using qRT-PCR and immunohistochemistry.
CONCLUSION: Our ER stress model performed a valuable prediction on breast cancer patients.

Keywords:  ER stress; breast cancer; immune infiltration; prognosis; risk-scoring model

DOI:  https://doi.org/10.1093/hmg/ddae170
bioRxiv. 2024 Dec 05. pii: 2024.11.30.626188. [Epub ahead of print]

Dynamic modulation of IRE1α-XBP1 signaling by adenovirus.

Yumi Jang, Fred Bunz.

The abundant production of foreign proteins and nucleic acids during viral infection elicits a variety of stress responses in host cells. Viral proteins that accumulate in the endoplasmic reticulum (ER) can trigger the unfolded protein response (UPR), a coordinated signaling program that culminates in the expression of downstream genes that collectively restore protein homeostasis. The model pathogen adenovirus serotype 5 (HAdV5) activates the UPR via the signaling axis formed by inositol-requiring enzyme type 1 (IRE1α) and the X-box binding protein 1 (XBP1), a transcription factor required for immune function. Recent studies have suggested that IRE1α-XBP1 activity supports adenovirus replication. Here, we show that HAdV5 exerted opposing effects on IRE1α and XBP1. IRE1α was activated in response to HAdV5 but the production of the XBP1 isoform, XBP1s, was post-transcriptionally blocked. The tumor suppressor p53, which is eliminated by HAdV5 after infection, inhibited IRE1α activation. The de-repression of IRE1α following the degradation of p53 conceivably reflects a novel antiviral mechanism, which HAdV5 ultimately evades by suppressing XBP1s. Our findings highlight the defective antiviral defenses in cancer cells and further illustrate the opposing mechanisms used by adenoviruses and their host cells to exert control over the UPR, a critical determinant of cell fate.

DOI: https://doi.org/10.1101/2024.11.30.626188
Cancers (Basel). 2024 Nov 26. pii: 3963. [Epub ahead of print]16(23):

Multiple Myeloma Cells with Increased Proteasomal and ER Stress Are Hypersensitive to ATX-101, an Experimental Peptide Drug Targeting PCNA.

Camilla Olaisen, Lisa Marie Røst, Animesh Sharma, Caroline Krogh Søgaard, Tiffany Khong, Sigrid Berg, Mi Jang, Aina Nedal, Andrew Spencer, Per Bruheim, Marit Otterlei.

  Objectives: To examine the regulatory role of PCNA in MM, we have targeted PCNA with the experimental drug ATX-101 in three commercial cell lines (JJN3, RPMI 1660, AMO) and seven in-house patient-derived cell lines with a more primary cell-like phenotype (TK9, 10, 12, 13, 14, 16 and 18) and measured the systemic molecular effects. Methods: We have used a multi-omics untargeted approach, measuring the gene expression (transcriptomics), a subproteomics approach measuring mainly signalling proteins and proteins in complex with these (signallomics) and quantitative metabolomics. These results are supplemented with traditional analysis, e.g., viability, Western and ELISA analysis. Results: The sensitivity of the cell lines to ATX-101 varied, including between three cell lines derived from the same patient at different times of disease. A trend towards increased sensitivity to ATX-101 during disease progression was detected. Although with different sensitivities, ATX-101 treatment resulted in numerous changes in signalling and metabolite pools in all cell lines. Transcriptomics and signallomics analysis of the TK cell lines revealed that elevated endogenous expression of ribosomal genes, elevated proteasomal and endoplasmic reticulum (ER) stress and low endogenous levels of NAD+ and NADH were associated with ATX-101 hypersensitivity. ATX-101 treatment further enhanced the ER stress, reduced primary metabolism and reduced the levels of the redox pair GSH/GSSG in sensitive cells. Signallome analysis suggested that eleven proteins (TPD52, TNFRS17/BCMA, LILRB4/ILT3, TSG101, ZNRF2, UPF3B, FADS2, C11orf38/SMAP, CGREF1, GAA, COG4) were activated only in the sensitive MM cell lines (TK13, 14 and 16 and JJN3), and not in nine other cancer cell lines or in primary monocytes. These proteins may therefore be biomarkers of cells with activated proteasomal and ER stress even though the gene expression levels of these proteins were not elevated. Interestingly, carfilzomib-resistant cells were at least as sensitive to ATX-101 as the wild-type cells, suggesting both low cross-resistance between ATX-101 and proteasome inhibitors and elevated proteasomal stress in carfilzomib-resistant cells. Conclusions: Our multi-omics approach revealed a vital role of PCNA in regulation of proteasomal and ER stress in MM.

Keywords:  PPP; glycolysis; metabolites; redox status; ribosomal gene expression

DOI:  https://doi.org/10.3390/cancers16233963
Cell Death Dis. 2024 Dec 18. 15(12): 910

MiR-378 exaggerates angiogenesis and bone erosion in collagen-induced arthritis mice by regulating endoplasmic reticulum stress.

Zhengmeng Yang, Nan Hou, Wenxiang Cheng, Xuan Lu, Ming Wang, Shanshan Bai, Yuejun Lin, Yaofeng Wang, Sien Lin, Peng Zhang, Micky D Tortorella, Lu Feng, Gang Li.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by pain, inflammation, and discomfort in the synovial joints. It is critical to understand the pathological mechanisms of RA progression. MicroRNA-378 (miR-378) is highly expressed in the synovium of RA patients and positively correlated with disease severity, but its function and underlying mechanisms remain poorly understood. In this study, miR-378 transgenic (miR-378high) mice were used to construct the collagen-induced arthritis (CIA) model for exploring the role of miR-378 in RA development. miR-378high CIA mice showed accelerated RA development, as evidenced by exaggerated joint swelling and bone structural deformities. More severe endoplasmic reticulum (ER) stress and the consequent angiogenesis and osteoclastogenesis were also activated in the synovial tissue and calcaneus, respectively, in the miR-378high group, suggesting that ER plays a significant role in miR-378-mediated RA pathogenesis. Upon in vitro RA induction, fibroblast-like synoviocytes (FLSs) isolated from miR-378high mice showed a higher expression level of ER stress markers. The conditioned medium (CM) from RA-FLSs of miR-378high mice stimulated more intensive angiogenesis and osteoclastogenesis. The ER stress-related protein Crebrf was identified as a downstream target of miR-378. Crebrf knockdown diminished the promoting effect of miR-378 on ER stress, as well as its downstream angiogenesis and osteoclastogenesis activities. Tail vein injection of anti-miR-378 lentivirus in an established RA mouse model was shown to ameliorate RA progression. In conclusion, miR-378 amplified RA development by promoting ER stress and downstream angiogenesis and osteoclastogenesis, thus indicating that miR-378 may be a potential therapeutic target for RA treatment.

DOI: https://doi.org/10.1038/s41419-024-07193-5
Cell Rep. 2024 Dec 14. pii: S2211-1247(24)01422-0. [Epub ahead of print]43(12): 115071

Temperature perception by ER UPR promotes preventive innate immunity and longevity.

Lei Zhou, Haoyu Zhuo, Jiaqi Jin, Anrui Pu, Qin Liu, Jiangbo Song, Xiaoling Tong, Haiqing Tang, Fangyin Dai.

  Microbial infectivity increases with rising environmental temperature, heightening the risk of infection to host organisms. The host's basal immunity is activated accordingly to mitigate upcoming pathogenic threats; still, how animals sense temperature elevation to adjust their preventive immune response remains elusive. This study reports that high temperature enhances innate immunity differently from pathogen infection. Unlike pathogen invasion requiring the mitochondrial unfolded protein response (UPR), high temperature engages the endoplasmic reticulum (ER) UPR to trigger the innate immune response. Furthermore, chronic activation of the XBP-1 UPR branch represses nucleolar ribosome biogenesis, a highly energy-consuming process, leading to lipid accumulation. The subsequent increase in oleic acid promotes the activation of the PMK-1 immune pathway. Additionally, ribosome biogenesis was identified as a regulator of longevity, wherein its impact is dependent on lipid metabolism and innate immunity. Collectively, our findings reveal the crucial role of ER-nucleolus crosstalk in shaping preventive immune responses and lifespan regulation.

Keywords:  C. elegans; CP: Cell biology; CP: Immunology; ER UPR; innate immunity; longevity; oleic acid; ribosome biogenesis; temperature

DOI:  https://doi.org/10.1016/j.celrep.2024.115071
Cell Death Dis. 2024 Dec 18. 15(12): 890

NIR-715 photodynamic therapy induces immunogenic cancer cell death by enhancing the endoplasmic reticulum stress response.

Zhen-Yuan Zheng, Wan Lin, Jia-Wan Su, Qing-Feng Huang, Cong Zhang, Wen-Xing Pan, En-Min Li, He-Feng Zhang, Li-Yan Xu.

Effectively interfering with endoplasmic reticulum (ER) function in tumor cells and simultaneously activating an anti-tumor immune microenvironment to attack the tumor cells are promising strategies for cancer treatment. However, precise ER-stress induction is still a huge challenge. In this study, we synthesized a near-infrared (NIR) probe, NIR-715, which induces tumor cell death and inhibits tumor growth without causing apparent side effects. NIR-715 triggers severe ER stress and immunogenic cell death (ICD) after visible light exposure. NIR-715 induced ICD-associated HMGB1 release in vitro and anti-tumor immune responses, including increased cytotoxic T lymphocyte (GZMB+ CD8+ T cell) infiltration and decreased numbers of exhausted T lymphocytes (PD-L1+ CD8+ T cell). These findings suggest that NIR-715 may be a novel agent for "cold" tumor photodynamic therapy (PDT). Schematic illustration of NIR-715 photodynamic therapy for visible light-triggered, endoplasmic reticulum-targeting antitumor therapy.

DOI: https://doi.org/10.1038/s41419-024-07283-4
J Cell Commun Signal. 2024 Dec;18(4): e12056

Emerging role of IRE1α in vascular diseases.

Jia Shi, Fan He, Xiaogang Du.

  A mounting body of evidence suggests that the endoplasmic reticulum stress and the unfolded protein response are involved in the underlying mechanisms responsible for vascular diseases. Inositol-requiring protein 1α (IRE1α), the most ancient branch among the UPR-related signaling pathways, can possess both serine/threonine kinase and endoribonuclease (RNase) activity and can perform physiological and pathological functions. The IRE1α-signaling pathway plays a critical role in the pathology of various vascular diseases. In this review, we provide a general overview of the physiological function of IRE1α and its pathophysiological role in vascular diseases.

Keywords:  IRE1α; XBP1; atherosclerosis; vascular disease

DOI:  https://doi.org/10.1002/ccs3.12056
Oncogene. 2024 Dec 17.

Mitochondrial unfolded protein response-dependent β-catenin signaling promotes neuroendocrine prostate cancer.

Jordan Alyse Woytash, Rahul Kumar, Ajay K Chaudhary, Cullan Donnelly, Adam Wojtulski, Murali Bethu, Jianmin Wang, Joseph Spernyak, Peter Bross, Neelu Yadav, Joseph R Inigo, Dhyan Chandra.

The mitochondrial unfolded protein response (UPRmt) maintains mitochondrial quality control and proteostasis under stress conditions. However, the role of UPRmt in aggressive and resistant prostate cancer is not clearly defined. We show that castration-resistant neuroendocrine prostate cancer (CRPC-NE) harbored highly dysfunctional oxidative phosphorylation (OXPHOS) Complexes. However, biochemical and protein analyses of CRPC-NE tumors showed upregulation of nuclear-encoded OXPHOS proteins and UPRmt in this lethal subset of prostate cancer suggestive of compensatory upregulation of stress signaling. Genetic deletion and pharmacological inhibition of the main chaperone of UPRmt heat shock protein 60 (HSP60) reduced neuroendocrine prostate cancer (NEPC) growth in vivo as well as reverted NEPC cells to a more epithelial-like state. HSP60-dependent aggressive NEPC phenotypes was associated with upregulation of β-catenin signaling both in cancer cells and in vivo tumors. HSP60 expression rendered enrichment of aggressive prostate cancer signatures and metastatic potential were inhibited upon suppression of UPRmt. We discovered that UPRmt promoted OXPHOS functions including mitochondrial bioenergetics in CRPC-NE via regulation of β-catenin signaling. Mitochondrial biogenesis facilitated cisplatin resistance and inhibition of UPRmt resensitizes CRPC-NE cells to cisplatin. Together, our findings demonstrated that UPRmt promotes mitochondrial health via upregulating β-catenin signaling and UPRmt represents viable therapeutic target for NEPC.

DOI: https://doi.org/10.1038/s41388-024-03261-4
Cell Death Discov. 2024 Dec 18. 10(1): 499

GALNTL5, which is restricted to mouse spermatids, impairs endoplasmic reticulum (ER) function through direct interaction with ER chaperone proteins.

Nobuyoshi Takasaki, Yoshihiro Koya, Mamoru Yamashita, Akihiro Nawa.

Polypeptide N-acetylgalactosaminyltransferase-like protein 5 (GALNTL5) was identified as a pp-GalNAc-T family gene. Nevertheless, GALNTL5 has no glycosyltransferase activity. In mice, Galntl5 expression is restricted to differentiating spermatids, and haploinsufficiency leads to immotile spermatozoa with an aberrant protein composition. Moreover, heterozygotic deletions of human GALNTL5 have been detected in patients diagnosed with asthenozoospermia (low sperm motility). Although these findings indicate that GALNTL5 is a functional molecule essential for mature sperm formation in mammals, the exact function of GALNTL5 in spermiogenesis remains unknown. To clarify this role, we established the mouse spermatocyte cell line GC-2spd(ts), which exhibits drug-inducible GALNTL5 expression. Interestingly, continuous GALNTL5 expression in the resultant cell lines caused apoptosis with cell shrinkage, and GALNTL5 was localized in the endoplasmic reticulum (ER) and was associated with two ER-resident chaperone proteins, calnexin and BiP (GRP78). Calnexin recognized and strongly bound to the N-glycans on GALNTL5 molecules modified in the ER. In contrast, ER-resident BiP likely attached to GALNL5 regardless of its glycosylation. GALNTL5 expression abolished the binding between calnexin and misfolded substrate proteins, indicating that GALNTL5 directly blocks calnexin function. Furthermore, the interaction between GALNTL5 and calnexin decreased the level of BiP protein, and consequently also the expression levels of proteins that are resident in the ER, Golgi apparatus, and cytoplasm. These reduced protein levels were confirmed by loss of calnexin or BiP function in the GC-2spd(ts) cell line using siRNA knockdown. Further, sustained expression of GALNTL5 resulted in cell structure changes, including the position of the cis-Golgi apparatus and alterations in the ER network. These results strongly suggest that GALNTL5 contributes to alteration of the cell structure specific to differentiating spermatids by blocking ER function.

DOI: https://doi.org/10.1038/s41420-024-02252-4
Int J Mol Sci. 2024 Dec 02. pii: 12944. [Epub ahead of print]25(23):

Advanced PROTAC and Quantitative Proteomics Strategy Reveals Bax Inhibitor-1 as a Critical Target of Icaritin in Burkitt Lymphoma.

Peixi Zhang, Ziqing Zhang, Jie Li, Meng Xu, Weiming Lu, Ming Chen, Jiaqi Shi, Qiaolai Wang, Hengyuan Zhang, Shi Huang, Chenlei Lian, Jia Liu, Junjie Ma, Jieqing Liu.

  Understanding the molecular targets of natural products is crucial for elucidating their mechanisms of action, mitigating toxicity, and uncovering potential therapeutic pathways. Icaritin (ICT), a bioactive flavonoid, demonstrates significant anti-tumor activity but lacks defined molecular targets. This study employs an advanced strategy integrating proteolysis targeting chimera (PROTAC) technology with quantitative proteomics to identify ICT's key targets. A library of 22 ICT-based PROTAC derivatives were synthesized, among which LJ-41 exhibited a superior IC50 of 5.52 μM against Burkitt lymphoma (CA-46) cells. Then, differential proteomic analysis identified Bax inhibitor-1 (BI-1) as a potential target. Target validation techniques, including cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) assay, surface plasmon resonance (SPR) assay, and molecular docking, confirmed LJ-41's high specificity for BI-1. Mechanistic investigations revealed that LJ-41 induces apoptosis through BI-1 degradation, triggering endoplasmic reticulum stress and activating inositol-requiring enzyme 1 α (IRE1α), activating transcription factor 6 (ATF6), and nuclear factor erythroid 2-related factor transcription factor heme oxygenase 1 (NRF2-HO-1) signaling pathways. This study establishes a refined methodological framework for natural product target discovery and highlights ICT-PROTAC derivatives' potential for clinical application in Burkitt lymphoma treatment.

Keywords:  PROTACs; anti-tumor; icaritin; mechanism of action; quantitative proteomics; target identification

DOI:  https://doi.org/10.3390/ijms252312944
Cell Death Dis. 2024 Dec 18. 15(12): 900

Dual functions of silibinin in attenuating aortic dissection via regulating iron homeostasis and endoplasmic reticulum stress against ferroptosis.

Zhen Qi, Qiu-Guo Wang, Meng-Xi Huang, Yi-Fan Zeng, Jing-Yu Li, Zhi-Cheng Duan, Ling Tan, Hao Tang.

Aortic dissection (AD) poses a significant threat to cardiovascular health globally, yet its underlying mechanisms remain elusive. Smooth muscle cells death and phenotypic switching are critically important pathological processes in AD. Currently, no pharmacological therapies have proven effective in managing AD. This study aims to elucidate the involvement of ferroptosis in AD progression and explore ferroptosis inhibition as a potential therapeutic approach for AD management. Elevated expression of ferroptosis markers (HMOX1, ACSL4, and 4-HNE) was observed in AD patients and β-Aminopropionitrile (BAPN)-induced mice. In vivo administration of silibinin (SIL) attenuated aortic dilation, inflammation, mitochondrial injury, and ferroptosis. SIL treatment enhanced cell viability and mitochondrial function while reducing reactive oxygen species (ROS) generation and mitigating ferroptosis in primary human aortic smooth muscle cells (HASMCs) induced by RSL3 or IKE. Mechanistically, RNA-sequencing analysis identified dysregulation of iron homeostasis and endoplasmic reticulum stress, which were modulated by SIL. Molecular docking, cellular thermal shift assay, drug affinity responsive target stability, and surface plasmon resonance analysis confirmed HMOX1 as a direct target of SIL, highlighting its role in modulating iron homeostasis. Moreover, NCT-502, a PHGDH inhibitor, reversed the protective effect of SIL in RSL3-induced HASMCs. Conversely, 4-PBA and ZnPP demonstrate a facilitative role. This suggests that SIL plays a crucial role in ferroptosis development by modulating iron homeostasis and endoplasmic reticulum stress-mediated serine biosynthesis, both in vitro and in vivo. Iron homeostasis and endoplasmic reticulum stress of HASMCs drive the development of aortic dissection. These findings unveil a novel role of SIL in mitigating ferroptosis in HASMCs, offering a promising therapeutic avenue for treating AD.

DOI: https://doi.org/10.1038/s41419-024-07309-x
Eur J Immunol. 2024 Dec 15. e202451348

KIRA6 is an Effective and Versatile Mast Cell Inhibitor of IgE-mediated Activation.

Veronika Wunderle, Thomas Wilhelm, Shatha Boukeileh, Jonas Goßen, Michael A Margreiter, Roman Sakurov, Sandro Capellmann, Maike Schwoerer, Nabil Ahmed, Gina Bronneberg, Michel Arock, Christian Martin, Thomas Schubert, Francesca Levi-Schaffer, Giulia Rossetti, Boaz Tirosh, Michael Huber.

  Mast cell (MC)-driven allergic diseases are constantly expanding and require the development of novel pharmacological MC stabilizers. Allergen/antigen (Ag)-triggered activation via crosslinking of the high-affinity receptor for IgE (FcεRI) is fundamentally regulated by SRC family kinases, for example, LYN and FYN, exhibiting positive and negative functions. We report that KIRA6, an inhibitor for the endoplasmic reticulum stress sensor IRE1α, suppresses IgE-mediated MC activation by inhibiting both LYN and FYN. KIRA6 attenuates Ag-stimulated early signaling and effector functions such as degranulation and proinflammatory cytokine production/secretion in murine bone marrow-derived MCs. Moreover, Ag-triggered bronchoconstriction in an ex vivo model and IgE-mediated stimulation of human MCs were repressed by KIRA6. The interaction of KIRA6 with three MC-relevant tyrosine kinases, LYN, FYN, and KIT, and the potential of KIRA6 structure as a pharmacophore for the development of respective single-, dual-, or triple-specificity inhibitors, was evaluated by homology modeling and molecular dynamics simulations. We found that KIRA6 particularly strongly binds the inactive state of LYN, FYN, and KIT with comparable affinities. In conclusion, our data suggest that the chemical structure of KIRA6 as a pharmacophore can be further developed to obtain an effective MC stabilizer.

Keywords:  IgE; allergy treatment; inflammation; mast cells; signal transduction

DOI:  https://doi.org/10.1002/eji.202451348