The Emerging Roles of Endoplasmic Reticulum Stress in Balancing Immunity and Tolerance in Health and Diseases: Mechanisms and Opportunities

The interplay between gut microbiota and the unfolded protein response: Implications for intestinal homeostasis preservation and dysbiosis-related diseases

The unfolded protein response (UPR) is a complex intracellular signal transduction system that orchestrates the cellular response during Endoplasmic Reticulum (ER) stress conditions to reestablish cellular proteostasis. If, on one side, prolonged ER stress conditions can lead to programmed cell death and autophagy as a cytoprotective mechanism, on the other, unresolved ER stress and improper UPR activation represent a perilous condition able to trigger or exacerbate inflammatory responses. Notably, intestinal and immune cells experience ER stress physiologically due to their high protein secretory rate. Indeed, there is evidence of UPR's involvement in both physiological and pathological intestinal conditions, while less is known about its bidirectional interaction with gut microbiota. However, gut microbes and their metabolites can influence ER stress and UPR pathways, and, in turn, ER stress conditions can shape gut microbiota composition, with important implications for overall intestinal health. Thus, targeting UPR components is an intriguing strategy for treating ER stress-linked dysbiosis and diseases, particularly intestinal inflammation.

CTGF regulated by ATF6 inhibits vascular endothelial inflammation and reduces hepatic ischemia-reperfusion injury

Vascular endothelial inflammation is crucial in hepatic ischemia-reperfusion injury (IRI). Our previous research has shown that connective tissue growth factor (CTGF), secreted by endothelial cells, protects against acute liver injury, but its upstream mechanism is unclear. We aimed to clarify the protective role of CTGF in endothelial cell inflammation during IRI and reveal the regulation between endoplasmic reticulum stress-induced activating transcription factor 6 (ATF6) and CTGF. Hypoxia/reoxygenation in endothelial cells, hepatic IRI in mice and clinical specimens were used to examine the relationships between CTGF and inflammatory factors and determine how ATF6 regulates CTGF and reduces damage. We found that activating ATF6 promoted CTGF expression and reduced liver damage in hepatic IRI. In vitro, activated ATF6 upregulated CTGF and downregulated inflammation, while ATF6 inhibition had the opposite effect. Dual-luciferase assays and chromatin immunoprecipitation confirmed that activated ATF6 binds to the CTGF promoter, enhancing its expression. Activated ATF6 increases CTGF and reduces extracellular regulated protein kinase 1/2 (ERK1/2) phosphorylation, decreasing inflammatory factors. Conversely, inhibiting ATF6 decreases CTGF and increases the phosphorylation of ERK1/2, increasing inflammatory factor levels. ERK1/2 inhibition reverses this effect. Clinical samples have shown that CTGF increases after IRI, inversely correlating with inflammatory cytokines. Therefore, ATF6 activation during liver IRI enhances CTGF expression and reduces endothelial inflammation via ERK1/2 inhibition, providing a novel target for diagnosing and treating liver IRI.

Immunoglobulin-binding protein and Toll-like receptors in immune landscape of breast cancer

Breast cancer (BC) is a complex disease exhibiting significant heterogeneity and encompassing various molecular subtypes. Among these, triple-negative breast cancer (TNBC) stands out as one of the most challenging types, characterized by its aggressive nature and poor prognosis. This review embarks on a comprehensive exploration of the immune landscape of BC, with a primary focus on the functional and structural characterization of immunoglobulin-binding protein (BiP) and its pivotal role in regulating the unfolded response (UPR) pathway of proteins. Moreover, we unravel the multifaceted functions of BiP in BC, with a special emphasis on the involvement of cell surface BiP in TNBC metastasis, drug resistance, and its contribution to the formation of the tumor microenvironment (TME). We also provide mechanistic insights into how ER-resident BiP mediates the sensitization of drug-resistant BC to different treatment strategies, thereby offering promising avenues for therapeutic intervention. We also delve into the role of Toll-like receptors (TLRs), shedding light on their diverse expression patterns across BC and their influence on modulating the tumor immune response. Understanding the interplay between BiP, TLRs, and the immune response, especially in TNBC, opens avenues for novel immunotherapies. Future research should focus on developing targeted therapies that activate ER-resident BiP or inhibit cell surface BiP, and modulate TLR signaling. Moreover, exploring BiP as a biomarker for TNBC diagnosis, prognosis, and treatment response will be crucial for personalized medicine.

Autoinflammatory patients with Golgi-trapped CDC42 exhibit intracellular trafficking defects leading to STING hyperactivation and ER stress

Most autoinflammatory diseases are caused by mutations in innate immunity genes. Previously, four variants in the RHO GTPase CDC42 were discovered in patients affected by syndromes generally characterized by neonatal-onset of cytopenia and auto-inflammation, including hemophagocytic lymphohistiocytosis and rash in the most severe form (NOCARH syndrome). However, the mechanisms responsible for these phenotypes remain largely elusive. Here, we show that the recurrent p.R186C CDC42 variant, which is trapped in the Golgi apparatus, elicits a block in both anterograde and retrograde transports. Consequently, it favours STING accumulation in the Golgi in a COPI-dependent manner. This is also observed for the other Golgi-trapped p.*192 C*24 CDC42 variant, but not for the p.Y64C and p.C188Y variants that do not accumulate in the Golgi. We demonstrate that the two Golgi-trapped CDC42 variants are the only ones that exhibit overactivation of the STING pathway and the type I interferon response, and elicit endoplasmic reticulum stress. Consistent with these results, patients carrying Golgi-trapped CDC42 mutants present very high levels of circulating IFNα at the onset of their disease. In conclusion, we report further mechanistic insights on the impact of the Golgi-trapped CDC42 variants. This increase in STING activation provides a rationale for combination treatments for these severe cases.

Polystyrene nanoparticles with different particle sizes cause autophagy by ROS/ERS/FOXO1 axis in the Cyprinus carpio kidney affecting immunological function

Microplastic pollution poses challenges for ecosystems worldwide, and nanoplastics (NPs, 1-1000 nm) have been identified as persistent pollutants. However, although some studies have described the hazards of NPs to aquatic organisms, the toxicological processes of NPs in the common carp kidney and the biotoxicity of differently sized NPs remain unclear. In this study, we used juvenile common carp as an in vivo model that were constantly exposed to freshwater at 1000 μg/L polystyrene nanoparticle (PSNP) concentrations (50, 100, and 400 nm) for 28 days. Simultaneously, we constructed an in vitro model utilizing grass fish kidney cells (CIK) to study the toxicological effects of PSNPs of various sizes. We performed RT-PCR and Western blot assays on the genes involved in FOXO1, HMGB1, HIF-1α, endoplasmic reticulum stress, autophagy, and immunoreaction. According to these results, exposure to PSNPs increased reactive oxygen species (ROS) levels, and the carp kidneys experienced endoplasmic reticulum stress. Additionally, PSNPs promoted renal autophagy by activating the ROS/ERS/FOXO1 (ERS: endoplasmic reticulum stress) pathway, and it affected immunological function by stimulating the ROS/HMGB1/HIF-1α signaling pathway. This study provides new insights into the contamination hazards of NPs in freshwater environments, as well as the harm they pose to the human living environments. The relationship between particle size and the degree of damage caused by PSNPs to organisms is a potential future research direction.

Flaring Inflammation and ER Stress by an Organelle-Specific Fluorescent Cage

The endoplasmic reticulum (ER) plays an important role in protein synthesis and its disruption can cause protein unfolding and misfolding. Accumulation of such proteins leads to ER stress, which ultimately promotes many diseases. Routine screening of ER activity in immune cells can flag serious conditions at early stages, but the current clinically used bio-probes have limitations. Herein, an ER-specific fluorophore based on a biocompatible benzothiadiazole-imine cage (BTD-cage) with excellent photophysical properties is developed. The cage outperforms commercially available ER stains in long-term live cell imaging with no fading or photobleaching over time. The cage is responsive to different levels of ER stress where its fluorescence increases accordingly. Incorporating the bio-probe into an immune disorder model, a 6-, 21-, and 48-fold increase in intensity is shown in THP-1, Raw 246.7, and Jurkat cells, respectively (within 15 min). These results strongly support that this system can be used for rapid visual and selective detection of ER stress. It is envisaged that tailoring molecular interactions and molecular recognition using supramolecular improved fluorophores can expand the library of biological probes for enhanced selectivity and targetability toward cellular organelles.

Harnessing External Irradiation for Precise Activation of Metal-Based Agents in Cancer Therapy

Cancer is a significant global health issue. Platinum-based chemotherapy drugs, including cisplatin, are crucial in clinical anti-cancer treatment. However, these drugs have limitations such as drug resistance, non-specific distribution, and irreversible toxic and side effects. In recent years, the development of metal-based agents has led to the discovery of other anti-cancer effects beyond chemotherapy. Precise spatiotemporal controlled external irradiation can activate metal-based agents at specific sites and play a different role from traditional chemotherapy. These strategies can not only enhance the anti-cancer efficiency, but also show fewer side effects and non-cross-drug resistance, which are ideal approaches to solve the problems caused by traditional platinum-based chemotherapy drugs. In this review, we focus on various metal-based agent-mediated cancer therapies that are activated by three types of external irradiation: near-infrared (NIR) light, ultrasound (US), and X-ray, and give some prospects. We hope that this review will promote the generation of new kinds of metal-based anti-cancer agents.

Endoplasmic reticulum stress-a key guardian in cancer

Endoplasmic reticulum stress (ERS) is a cellular stress response characterized by excessive contraction of the endoplasmic reticulum (ER). It is a pathological hallmark of many diseases, such as diabetes, obesity, and neurodegenerative diseases. In the unique growth characteristic and varied microenvironment of cancer, high levels of stress are necessary to maintain the rapid proliferation and metastasis of tumor cells. This process is closely related to ERS, which enhances the ability of tumor cells to adapt to unfavorable environments and promotes the malignant progression of cancer. In this paper, we review the roles and mechanisms of ERS in tumor cell proliferation, apoptosis, metastasis, angiogenesis, drug resistance, cellular metabolism, and immune response. We found that ERS can modulate tumor progression via the unfolded protein response (UPR) signaling of IRE1, PERK, and ATF6. Targeting the ERS may be a new strategy to attenuate the protective effects of ERS on cancer. This manuscript explores the potential of ERS-targeted therapies, detailing the mechanisms through which ERS influences cancer progression and highlighting experimental and clinical evidence supporting these strategies. Through this review, we aim to deepen our understanding of the role of ER stress in cancer development and provide new insights for cancer therapy.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

Identification of novel endoplasmic reticulum-related genes and their association with immune cell infiltration in major depressive disorder

BACKGROUND

Several lines of evidence point to an interaction between genetic predisposition and environmental factors in the onset of major depressive disorder (MDD). This study is aimed to investigate the pathogenesis of MDD by identifying key biomarkers, associated immune infiltration using bioinformatic analysis and human postmortem sample.

METHODS

The Gene Expression Omnibus (GEO) database of GSE98793 was adopted to identify hub genes linked to endoplasmic reticulum (ER) stress-related genes (ERGs) in MDD. Another GEO database of GSE76826 was employed to validate the novel target associated with ERGs and immune infiltration in MDD. Moreover, human postmortem sample from MDD patients was utilized to confirm the differential expression analysis of hub genes.

RESULTS

We discovered 12 ER stress-related differentially expressed genes (ERDEGs). A LASSO Cox regression analysis helped construct a diagnostic model for these ERDEGs, incorporating immune infiltration analysis revealed that three hub genes (ERLIN1, SEC61B, and USP13) show the significant and consistent expression differences between the two groups. Western blot analysis of postmortem brain samples indicated notably higher expression levels of ERLIN1 and SEC61B in the MDD group, with USP13 also tending to increase compared to control group.

LIMITATIONS

The utilization of the MDD gene chip in this analysis was sourced from the GEO database, which possesses a restricted number of pertinent gene chip samples.

CONCLUSIONS

These findings indicate that ERDEGs especially including ERLIN1, SEC61B, and USP13 associated the infiltration of immune cells may be potential diagnostic indicators for MDD.

Adolescent BCG revaccination induces a phenotypic shift in CD4+ T cell responses to Mycobacterium tuberculosis

A recent clinical trial demonstrated that Bacille Calmette-Guérin (BCG) revaccination of adolescents reduced the risk of sustained infection with Mycobacterium tuberculosis (M.tb). In a companion phase 1b trial, HVTN 602/Aeras A-042, we characterize in-depth the cellular responses to BCG revaccination or to a H4:IC31 vaccine boost to identify T cell subsets that could be responsible for the protection observed. High-dimensional clustering analysis of cells profiled using a 26-color flow cytometric panel show marked increases in five effector memory CD4+ T cell subpopulations (TEM) after BCG revaccination, two of which are highly polyfunctional. CITE-Seq single-cell analysis shows that the activated subsets include an abundant cluster of Th1 cells with migratory potential. Additionally, a small cluster of Th17 TEM cells induced by BCG revaccination expresses high levels of CD103; these may represent recirculating tissue-resident memory cells that could provide pulmonary immune protection. Together, these results identify unique populations of CD4+ T cells with potential to be immune correlates of protection conferred by BCG revaccination.

Potential Hepatoprotective Effects of Irbesartan, an Accessible Angiotensin II Receptor Blocker, Against Cisplatin-Induced Liver Injury in a Rat Model

Objectives

Drug-induced liver injury is a common adverse reaction that frequently occurs with chemotherapeutic agents, such as cisplatin (CIS). This study seeks to enhance our understanding of drug actions and their associated adverse effects by examining the toxicity of CIS on rat liver tissue. We aimed to investigate the potential hepatoprotective effects of irbesartan (IRB), an easily accessible angiotensin II receptor blocker, in mitigating CIS-induced hepatotoxicity.

Materials and Methods

Wistar albino rats were divided into four groups. These groups included a control group [saline, per oral (p.o.)] for seven days, and 1 mL saline intraperitoneal [(i.p.) on the fourth day]; a CIS group (1 mL saline for seven days and 7.5 mg/kg CIS i.p. on the fourth day); a CIS + IRB group (IRB: 50 mg/kg p.o. for seven days and 7.5 mg/kg CIS i.p. on the fourth day), and an IRB group (50 mg/kg IRB p.o. for seven days). The effect of IRB on interleukin-1 beta (IL-1β) and caspase 3 levels was evaluated by immunohistochemical analysis, and its effects on mRNA expression levels of CCAAT/enhancer-binding protein homologous protein (CHOP) and immunoglobulin-heavy-chain-binding protein (BiP) were tested by quantitative real-time polymerase chain reaction.

Results

IRB administration mitigated CIS-induced liver toxicity by inhibiting endoplasmic reticulum (ER) stress. Specifically, this drug reduced the mRNA expression of ER stress markers, including CHOP and BiP. In addition, IRB treatment decreased oxidative stress, inflammatory responses, and apoptotic markers.

Conclusion

These findings suggest that IRB is a promising therapeutic option for preventing CIS-induced liver injury, potentially by modulating ER stress-related pathways.

Insights into the Activation of Unfolded Protein Response Mechanism during Coronavirus Infection

Coronaviruses represent a significant class of viruses that affect both animals and humans. Their replication cycle is strongly associated with the endoplasmic reticulum (ER), which, upon virus invasion, triggers ER stress responses. The activation of the unfolded protein response (UPR) within infected cells is performed from three transmembrane receptors, IRE1, PERK, and ATF6, and results in a reduction in protein production, a boost in the ER's ability to fold proteins properly, and the initiation of ER-associated degradation (ERAD) to remove misfolded or unfolded proteins. However, in cases of prolonged and severe ER stress, the UPR can also instigate apoptotic cell death and inflammation. Herein, we discuss the ER-triggered host responses after coronavirus infection, as well as the pharmaceutical targeting of the UPR as a potential antiviral strategy.

Non-canonical activation of IRE1α during Candida albicans infection enhances macrophage fungicidal activity

While the canonical function of IRE1α is to detect misfolded proteins and activate the unfolded protein response (UPR) to maintain cellular homeostasis, microbial pathogens can also activate IRE1α, which modulates innate immunity and infection outcomes. However, how infection activates IRE1α and its associated inflammatory functions have not been fully elucidated. Recognition of microbe-associated molecular patterns can activate IRE1α, but it is unclear whether this depends on protein misfolding. Here, we report that a common and deadly fungal pathogen, Candida albicans, activates macrophage IRE1α through C-type lectin receptor signaling, reinforcing a role for IRE1α as a central regulator of host responses to infection by a broad range of pathogens. This activation did not depend on protein misfolding in response to C. albicans infection. Moreover, lipopolysaccharide treatment was also able to activate IRE1α prior to protein misfolding, suggesting that pathogen-mediated activation of IRE1α occurs through non-canonical mechanisms. During C. albicans infection, we observed that IRE1α activity promotes phagolysosomal fusion that supports the fungicidal activity of macrophages. Consequently, macrophages lacking IRE1α activity displayed inefficient phagosome maturation, enabling C. albicans to lyse the phagosome, evade fungal killing, and drive aberrant inflammatory cytokine production. Mechanistically, we show that IRE1α activity supports phagosomal calcium flux after phagocytosis of C. albicans, which is crucial for phagosome maturation. Importantly, deletion of IRE1α activity decreased the fungicidal activity of phagocytes in vivo during systemic C. albicans infection. Together, these data provide mechanistic insight for the non-canonical activation of IRE1α during infection, and reveal central roles for IRE1α in macrophage antifungal responses.

Direct neuronal reprogramming of NDUFS4 patient cells identifies the unfolded protein response as a novel general reprogramming hurdle

Mitochondria account for essential cellular pathways, from ATP production to nucleotide metabolism, and their deficits lead to neurological disorders and contribute to the onset of age-related diseases. Direct neuronal reprogramming aims at replacing neurons lost in such conditions, but very little is known about the impact of mitochondrial dysfunction on the direct reprogramming of human cells. Here, we explore the effects of mitochondrial dysfunction on the neuronal reprogramming of induced pluripotent stem cell (iPSC)-derived astrocytes carrying mutations in the NDUFS4 gene, important for Complex I and associated with Leigh syndrome. This led to the identification of the unfolded protein response as a major hurdle in the direct neuronal conversion of not only astrocytes and fibroblasts from patients but also control human astrocytes and fibroblasts. Its transient inhibition potently improves reprogramming by influencing the mitochondria-endoplasmic-reticulum-stress-mediated pathways. Taken together, disease modeling using patient cells unraveled novel general hurdles and ways to overcome these in human astrocyte-to-neuron reprogramming.

Endoplasmic reticulum stress regulators exhibit different prognostic, therapeutic and immune landscapes in pancreatic adenocarcinoma

Endoplasmic reticulum stress (ERS) and unfolded protein response are the critical processes of tumour biology. However, the roles of ERS regulatory genes in pancreatic adenocarcinoma (PAAD) remain elusive. A novel ERS-related risk signature was constructed using the Lasso regression analysis. Its prognostic value, immune effect, metabolic influence, mutational feature and therapeutic correlation were comprehensively analysed through multiple bioinformatic approaches. The biofunctions of KDELR3 and YWHAZ in pancreatic cancer (PC) cells were also investigated through colony formation, Transwell assays, flow cytometric detection and a xenograft model. The upstream miRNA regulatory mechanism of KDELR3 was predicted and validated. ERS risk score was identified as an independent prognostic factor and could improve traditional prognostic model. Meanwhile, it was closely associated with metabolic reprogramming and tumour immune. High ERS risk enhanced glycolysis process and nucleotide metabolism, but was unfavourable for anti-tumour immune response. Moreover, ERS risk score could act as a potential biomarker for predicting the efficacy of ICBs. Overexpression of KDELR3 and YWHAZ stimulated the proliferation, migration and invasion of SW1990 and BxPC-3 cells. Silencing KDELR3 suppressed tumour growth in a xenograft model. miR-137 could weaken the malignant potentials of PC cells through inhibiting KDELR3 (5'-AGCAAUAA-3'). ERS risk score greatly contributed to PAAD clinical assessment. KDELR3 and YWHAZ possessed cancer-promoting capacities, showing promise as a novel treatment target.

Intrinsic factors behind long COVID: IV. Hypothetical roles of the SARS-CoV-2 nucleocapsid protein and its liquid-liquid phase separation

When the SARS-CoV-2 virus infects humans, it leads to a condition called COVID-19 that has a wide spectrum of clinical manifestations, from no symptoms to acute respiratory distress syndrome. The virus initiates damage by attaching to the ACE-2 protein on the surface of endothelial cells that line the blood vessels and using these cells as hosts for replication. Reactive oxygen species levels are increased during viral replication, which leads to oxidative stress. About three-fifths (~60%) of the people who get infected with the virus eradicate it from their body after 28 days and recover their normal activity. However, a large fraction (~40%) of the people who are infected with the virus suffer from various symptoms (anosmia and/or ageusia, fatigue, cough, myalgia, cognitive impairment, insomnia, dyspnea, and tachycardia) beyond 12 weeks and are diagnosed with a syndrome called long COVID. Long-term clinical studies in a group of people who contracted SARS-CoV-2 have been contrasted with a noninfected matched group of people. A subset of infected people can be distinguished by a set of cytokine markers to have persistent, low-grade inflammation and often self-report two or more bothersome symptoms. No medication can alleviate their symptoms efficiently. Coronavirus nucleocapsid proteins have been investigated extensively as potential drug targets due to their key roles in virus replication, among which is their ability to bind their respective genomic RNAs for incorporation into emerging virions. This review highlights basic studies of the nucleocapsid protein and its ability to undergo liquid-liquid phase separation. We hypothesize that this ability of the nucleocapsid protein for phase separation may contribute to long COVID. This hypothesis unlocks new investigation angles and could potentially open novel avenues for a better understanding of long COVID and treating this condition.

SSR1 and CKAP4 as potential biomarkers for intervertebral disc degeneration based on integrated bioinformatics analysis

Background

Intervertebral disc degeneration (IDD) is a significant cause of low back pain and poses a significant public health concern. Genetic factors play a crucial role in IDD, highlighting the need for a better understanding of the underlying mechanisms.

Aim

The aim of this study was to identify potential IDD-related biomarkers using a comprehensive bioinformatics approach and validate them in vitro.

Materials and Methods

In this study, we employed several analytical approaches to identify the key genes involved in IDD. We utilized weighted gene coexpression network analysis (WGCNA), MCODE, LASSO algorithms, and ROC curves to identify the key genes. Additionally, immune infiltrating analysis and a single-cell sequencing dataset were utilized to further explore the characteristics of the key genes. Finally, we conducted in vitro experiments on human disc tissues to validate the significance of these key genes in IDD.

Results

we obtained gene expression profiles from the GEO database (GSE23130 and GSE15227) and identified 1015 DEGs associated with IDD. Using WGCNA, we identified the blue module as significantly related to IDD. Among the DEGs, we identified 47 hub genes that overlapped with the genes in the blue module, based on criteria of |logFC| ≥ 2.0 and p.adj <0.05. Further analysis using both MCODE and LASSO algorithms enabled us to identify five key genes, of which CKAP4 and SSR1 were validated by GSE70362, demonstrating significant diagnostic value for IDD. Additionally, immune infiltrating analysis revealed that monocytes were significantly correlated with the two key genes. We also analyzed a single-cell sequencing dataset, GSE199866, which showed that both CKAP4 and SSR1 were highly expressed in fibrocartilage chondrocytes. Finally, we validated our findings in vitro by performing real time polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) on 30 human disc samples. Our results showed that CKAP4 and SSR1 were upregulated in degenerated disc samples. Taken together, our findings suggest that CKAP4 and SSR1 have the potential to serve as disease biomarkers for IDD.

Benefits and Pitfalls of a Glycosylation Inhibitor Tunicamycin in the Therapeutic Implication of Cancers

The aberrant glycosylation is a hallmark of cancer progression and chemoresistance. It is also an immune therapeutic target for various cancers. Tunicamycin (TM) is one of the potent nucleoside antibiotics and an inhibitor of aberrant glycosylation in various cancer cells, including breast cancer, gastric cancer, and pancreatic cancer, parallel with the inhibition of cancer cell growth and progression of tumors. Like chemotherapies such as doxorubicin (DOX), 5'fluorouracil, etoposide, and cisplatin, TM induces the unfolded protein response (UPR) by blocking aberrant glycosylation. Consequently, stress is induced in the endoplasmic reticulum (ER) that promotes apoptosis. TM can thus be considered a potent antitumor drug in various cancers and may promote chemosensitivity. However, its lack of cell-type-specific cytotoxicity impedes its anticancer efficacy. In this review, we focus on recent advances in our understanding of the benefits and pitfalls of TM therapies in various cancers, including breast, colon, and pancreatic cancers, and discuss the mechanisms identified by which TM functions. Finally, we discuss the potential use of nano-based drug delivery systems to overcome non-specific toxicity and enhance the therapeutic efficacy of TM as a targeted therapy.

Sotagliflozin attenuates liver-associated disorders in cystic fibrosis rabbits

Mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene lead to CF, a life-threating autosomal recessive genetic disease. While recently approved Trikafta dramatically ameliorates CF lung diseases, there is still a lack of effective medicine to treat CF-associated liver disease (CFLD). To address this medical need, we used a recently established CF rabbit model to test whether sotagliflozin, a sodium-glucose cotransporter 1 and 2 (SGLT1/2) inhibitor drug that is approved to treat diabetes, can be repurposed to treat CFLD. Sotagliflozin treatment led to systemic benefits to CF rabbits, evidenced by increased appetite and weight gain as well as prolonged lifespan. For CF liver-related phenotypes, the animals benefited from normalized blood chemistry and bile acid parameters. Furthermore, sotagliflozin alleviated nonalcoholic steatohepatitis-like phenotypes, including liver fibrosis. Intriguingly, sotagliflozin treatment markedly reduced the otherwise elevated endoplasmic reticulum stress responses in the liver and other affected organs of CF rabbits. In summary, our work demonstrates that sotagliflozin attenuates liver disorders in CF rabbits and suggests sotagliflozin as a potential drug to treat CFLD.

Pan-cancer scRNA-seq analysis reveals immunological and diagnostic significance of the peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMCs) reflect systemic immune response during cancer progression. However, a comprehensive understanding of the composition and function of PBMCs in cancer patients is lacking, and the potential of these features to assist cancer diagnosis is also unclear. Here, the compositional and status differences between cancer patients and healthy donors in PBMCs were investigated by single-cell RNA sequencing (scRNA-seq), involving 262,025 PBMCs from 68 cancer samples and 14 healthy samples. We observed an enhanced activation and differentiation of most immune subsets in cancer patients, along with reduction of naïve T cells, expansion of macrophages, impairment of NK cells and myeloid cells, as well as tumor promotion and immunosuppression. Based on characteristics including differential cell type abundances and/or hub genes identified from weight gene co-expression network analysis (WGCNA) modules of each major cell type, we applied logistic regression to construct cancer diagnosis models. Furthermore, we found that the above models can distinguish cancer patients and healthy donors with high sensitivity. Our study provided new insights into using the features of PBMCs in non-invasive cancer diagnosis.

Heterozygous mutations in the C-terminal domain of COPA underlie a complex autoinflammatory syndrome

Mutations in the N-terminal WD40 domain of coatomer protein complex subunit α (COPA) cause a type I interferonopathy, typically characterized by alveolar hemorrhage, arthritis, and nephritis. We described 3 heterozygous mutations in the C-terminal domain (CTD) of COPA (p.C1013S, p.R1058C, and p.R1142X) in 6 children from 3 unrelated families with a similar syndrome of autoinflammation and autoimmunity. We showed that these CTD COPA mutations disrupt the integrity and the function of coat protein complex I (COPI). In COPAR1142X and COPAR1058C fibroblasts, we demonstrated that COPI dysfunction causes both an anterograde ER-to-Golgi and a retrograde Golgi-to-ER trafficking defect. The disturbed intracellular trafficking resulted in a cGAS/STING-dependent upregulation of the type I IFN signaling in patients and patient-derived cell lines, albeit through a distinct molecular mechanism in comparison with mutations in the WD40 domain of COPA. We showed that CTD COPA mutations induce an activation of ER stress and NF-κB signaling in patient-derived primary cell lines. These results demonstrate the importance of the integrity of the CTD of COPA for COPI function and homeostatic intracellular trafficking, essential to ER homeostasis. CTD COPA mutations result in disease by increased ER stress, disturbed intracellular transport, and increased proinflammatory signaling.

Quercetin Attenuates Endoplasmic Reticulum Stress and Apoptosis in TNBS-Induced Colitis by Inhibiting the Glucose Regulatory Protein 78 Activation

Background

The inflammatory bowel diseases (IBD) are significantly influenced by apoptosis and endoplasmic reticulum (ER) stress.

Aims

To investigate the effects of quercetin on ER stress-mediated apoptosis in a trinitrobenzene sulfonic acid (TNBS) induced experimental IBD model.

Study Design

In vivo animal experimental study.

Methods

To demonstrate the effect of quercetin in an experimental colitis model, Control, TNBS, and TNBS+quercetin groups were created with 24 Wistar Albino rats. Colitis was induced by intrarectal administration of 25 mg TNBS. In the TNBS+quercetin group, intragastrically 100 mg/kg quercetin was given for 7 days, immediately after colitis induction. In the TNBS-induced experimental IBD model, we evaluated the effects of quercetin on colonic epithelial cell apoptosis, oxidative stress, ER stress, the mitogen-activated protein kinase c-Jun N-terminal kinase, and the nuclear factor kappa B immunoreactivities, the levels of myeloperoxidase and tumor necrosis factor-α, the disease activity index with colonic histopathologic changes.

Results

TNBS administration induced an elevated level of disease activity and oxidative stress indices, inflammation markers, and an increase in the immunoreactivities of nuclear factor kappa B and the mitogen-activated protein kinase c-Jun N-terminal kinase in the colon of the colitis group. Glucose regulatory protein 78, caspase-12 immunoreactivities, and epithelial cell apoptosis also were shown in the colon. However, quercetin improved TNBS-induced histopathological alterations, apoptosis, inflammation, oxidative stress, and ER stress.

Conclusion

This study suggests that quercetin has a regulatory effect on ER stress-mediated apoptosis, and thus may be beneficial in treating IBD.

Immunologic Crosstalk of Endoplasmic Reticulum Stress Signaling in Bladder Cancer

Bladder cancer (BC) is a common malignant tumor of the urinary system. While current approaches involving adjuvant chemotherapy, radiotherapy, and immunotherapy have shown significant progress in BC treatment, challenges, such as recurrence and drug resistance, persist, especially in the case of muscle-invasive bladder cancer (MIBC). It is mainly due to the lack of pre-existing immune response cells in the tumor immune microenvironment. Micro-environmental changes (such as hypoxia and under-nutrition) can cause the aggregation of unfolded and misfolded proteins in the lumen, which induces endoplasmic reticulum (ER) stress. ER stress and its downstream signaling pathways are closely related to immunogenicity and tumor drug resistance. ER stress plays a pivotal role in a spectrum of processes within immune cells and the progression of BC cells, encompassing cell proliferation, autophagy, apoptosis, and resistance to therapies. Recent studies have increasingly recognized the potential of natural compounds to exhibit anti-BC properties through ER stress induction. Still, the efficacy of these natural compounds remains less than that of immune checkpoint inhibitors (ICIs). Currently, the ER stress-mediated immunogenic cell death (ICD) pathway is more encouraging, which can enhance ICI responses by mediating immune stemness. This article provides an overview of the recent developments in understanding how ER stress influences tumor immunity and its implications for BC. Targeting this pathway may soon emerge as a compelling therapeutic strategy for BC.

Essential requirement for IER3IP1 in B cell development

In a forward genetic screen of mice with N-ethyl-N-nitrosourea-induced mutations for aberrant immune function, we identified animals with low percentages of B220+ cells in the peripheral blood. The causative mutation was in Ier3ip1, encoding immediate early response 3 interacting protein 1 (IER3IP1), an endoplasmic reticulum membrane protein mutated in an autosomal recessive neurodevelopmental disorder termed Microcephaly with simplified gyration, Epilepsy and permanent neonatal Diabetes Syndrome (MEDS) in humans. However, no immune function for IER3IP1 had previously been reported. The viable hypomorphic Ier3ip1 allele uncovered in this study, identical to a reported IER3IP1 variant in a MEDS patient, reveals an essential hematopoietic-intrinsic role for IER3IP1 in B cell development and function. We show that IER3IP1 forms a complex with the Golgi transmembrane protein 167A and limits activation of the unfolded protein response mediated by inositol-requiring enzyme-1α and X-box binding protein 1 in B cells. Our findings suggest that B cell deficiency may be a feature of MEDS.

TSG-6 alleviates cerebral ischemia/reperfusion injury and blood-brain barrier disruption by suppressing ER stress-mediated inflammation

Tumor necrosis factor-stimulated gene-6 (TSG-6) exhibits promising neuroprotective activity, but how it influences cerebral ischemia/reperfusion (CIR) injury remains to be established. Here, the impact of TSG-6 on the CIR-induced disturbance in the blood-brain barrier (BBB) and associated neurological degeneration was assessed, and the related molecular processes were explored. In this study, TSG-6 markedly reduced CIR-mediated increases in neurological deficit scores, decreased infarct volume, and protected against the apoptotic death of neurons in MCAO/R model rats. Similarly, TSG-6 pretreatment protected cultured neurons against OGD/R-associated neuronal death. TSG-6 also restored BBB integrity, suppressing PERK-eIF2α and IRE1α-TRAF2 pathway activation in CIR model systems, thereby inhibiting NF-κB, TNF-α, IL-1β, and IL-6. The further use of specific inhibitors of ER stress, 4-phenyl butyric acid (4-PBA), PERK (GSK2656157), and IRE1α (STF083010) demonstrated the ability of ER stress to drive inflammatory activity in the context of CIR injury i the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways. Consistently, the activation of ER stress using tunicamycin resulted in reversing the beneficial effects of TSG-6 on CIR-associated BBB disruption and neurological damage in vitro and in vivo. Treatment with TSG-6 can protect against CIR injury via the inhibition of ER stress-related inflammatory activity induced through the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways.

Enterotoxins A and B produced by Staphylococcus aureus increase cell proliferation, invasion and cytarabine resistance in acute myeloid leukemia cell lines

As in the case of cancer, the risk of infection increases when the host's immune system is not working properly. It has been shown that toxins produced by the bacteria responsible for bacterial infections can alter the properties of cancer cells as well as their sensitivity to chemotherapy agents. Staphylococcus aureus (S. aureus) is one of the most prevalent pathogens in acute myeloid leukemia (AML) patients and it produces several virulence factors, including Staphylococcal enterotoxin A (SEA) and Staphylococcal enterotoxin B (SEB). Cytotoxicity, transwell migration, invasion assays, and various transcriptomic and gene set enrichment (GSE) analyses were used to determine how SEA and SEB alter cell proliferation, migration, invasion, and Cytarabine (Cyt) resistance in AML cell lines. The treatment of AML cell lines with SEA/SEB caused an increase in cell proliferation and Cyt resistance. Toxins enhanced the proclivity of cells to migrate and invade, with around 50% of cells in the presence of SEA and SEB. Transcriptomic and gene set enrichment analyses, and subsequent PCR validations showed dysregulation of immune related genes and genesets. Apparently, this allows AML cells to escape and survive the undesirable environment created by toxins, possibly via the ER stress signaling pathway. Therefore, SEA and SEB can significantly alter the characteristics of AML cancer cells and evaluation of alterations in responsible immune genes and pathways may be crucial for controlling the progression of cancer. In addition, our results suggest that there may be a strong interaction between the immune related pathways and the ER signaling pathway.

Parkinson's Disease: Exploring Different Animal Model Systems

Disease modeling in non-human subjects is an essential part of any clinical research. To gain proper understanding of the etiology and pathophysiology of any disease, experimental models are required to replicate the disease process. Due to the huge diversity in pathophysiology and prognosis in different diseases, animal modeling is customized and specific accordingly. As in other neurodegenerative diseases, Parkinson's disease is a progressive disorder coupled with varying forms of physical and mental disabilities. The pathological hallmarks of Parkinson's disease are associated with the accumulation of misfolded protein called α-synuclein as Lewy body, and degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) area affecting the patient's motor activity. Extensive research has already been conducted regarding animal modeling of Parkinson's diseases. These include animal systems with induction of Parkinson's, either pharmacologically or via genetic manipulation. In this review, we will be summarizing and discussing some of the commonly employed Parkinson's disease animal model systems and their applications and limitations.

Endoplasmic Reticulum Stress in the Brain Tumor Immune Microenvironment

Immunotherapy has emerged as a powerful strategy for halting cancer progression. However, primary malignancies affecting the brain have been exempt to this success. Indeed, brain tumors continue to portend severe morbidity and remain a globally lethal disease. Extensive efforts have been directed at understanding how tumor cells survive and propagate within the unique microenvironment of the central nervous system (CNS). Cancer genetic aberrations and metabolic abnormalities provoke a state of persistent endoplasmic reticulum (ER) stress that in turn promotes tumor growth, invasion, therapeutic resistance, and the dynamic reprogramming of the infiltrating immune cells. Consequently, targeting ER stress is a potential therapeutic approach. In this work, we provide an overview of how ER stress response is advantageous to brain tumor development, discuss the significance of ER stress in governing antitumor immunity, and put forth therapeutic strategies of regulating ER stress to augment the effect of immunotherapy for primary CNS tumors.

Unveiling the Role of Dynamic Alternative Splicing Modulation After Infestation with Sea Lice (Caligus rogercresseyi) in Atlantic Salmon

Sea lice are pathogenic marine ectoparasite copepods that represent a severe risk to the worldwide salmon industry. Several transcriptomic investigations have characterized the regulation of gene expression response of Atlantic salmon to sea lice infestation. These studies have focused on the levels of transcript, overlooking the potentially relevant role of alternative splicing (AS), which corresponds to an essential control mechanism of gene expression through RNA processing. In the present study, we performed a genome-wide bioinformatics characterization of differential AS event dynamics in control and infested C. rogercresseyi Atlantic salmon and in resistant and susceptible phenotypes. We identified a significant rise of alternative splicing events and AS genes after infestation and 176 differential alternative splicing events (DASE) from 133 genes. In addition, a higher number of DASE and AS genes were observed among resistant and susceptible phenotypes. Functional annotation of AS genes shows several terms and pathways associated with behavior, RNA splicing, immune response, and RNA binding. Furthermore, three protein-coding genes were identified undergoing differential transcript usage events, among resistant and susceptible phenotypes. Our findings support AS performing a relevant regulatory role in the response of salmonids to sea lice infestation.

A Pilot Study on Blood Components in COVID-19 Affected Subjects: A Correlation to UPR Signalling and ER-Stress

Abstract

The endoplasmic reticulum (ER) is the site for protein synthesis, its folding and secretion. An intricate set of signalling pathways, called UPR pathways, have been evolved by ER in mammalian cells, to allow the cell to respond the presence of misfolded proteins within the ER. Breaching of these signalling systems by disease oriented accumulation of unfolded proteins may develop cellular stress. The aim of this study is to explore whether COVID-19 infection is responsible for developing this kind of endoplasmic reticulum related stress (ER-stress). ER-stress was evaluated by checking the expression of ER-stress markers e.g. PERK (adapting) and TRAF2 (alarming). ER-stress was correlated to several blood parameters viz. IgG, pro- and anti-inflammatory cytokines, leukocytes, lymphocytes, RBC, haemoglobin and PaO₂/FiO₂ ratio (ratio of arterial oxygen partial pressure to fractional inspired oxygen) in COVID-19 affected subjects. COVID-19 infection was found to be a state of protein homeostasis (proteostasis) collapse. Changes in IgG levels showed very poor immune response by the infected subjects. At the initial phase of the disease, pro-inflammatory cytokine levels were high and anti-inflammatory cytokines levels were low; though they were partly compromised at later phase of the disease. Total leukocyte concentration increased over the period of time; while percentage of lymphocytes were dropped. No significant changes were observed in cases of RBC counts and haemoglobin (Hb) levels. Both RBC and Hb were maintained at their normal range. In mildly stressed group, PaO₂/FiO₂ ratio (oxygenation status) was in the higher side of normal range; whereas in other two groups the ratio was in respiratory distress syndrome mode. Virus could induce mild to severe ER-stress, which could be the cause of cellular death and systemic dysfunction introducing fatal consequences.

Graphical Abstract

Schematic representation of SARS-CoV-2 infection and related consequences.

Assessing the Immune Cell Subset and Genetic Mutations in Patients With Palindromic Rheumatism Seronegative for Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide

OBJECTIVE

The etiology underlying cases of palindromic rheumatism (PR) not associated with other rheumatic diseases in patients who are seronegative for rheumatoid factor and anti-cyclic citrullinated peptide (seronegative PR) is unclear. We aimed to investigate the immune cells and genes involved.

METHODS

This was a single-center comparative study of 48 patients with seronegative PR and 48 healthy controls. Mass cytometry and RNA sequencing were used to identify distinct immune cell subsets in blood. Among the 48 seronegative PR patients, plasma samples from 40 patients were evaluated by enzyme-linked immunosorbent assay for cytokine levels, and peripheral blood samples from 25 patients were evaluated by flow cytometry for mononuclear cell subsets. Plasma samples from 21 patients were evaluated by real-time polymerase chain reaction for differential gene and protein expression, and samples from 3 patients were analyzed with whole-exome sequencing for gene mutations.

RESULTS

Immunophenotyping revealed a markedly increased frequency of CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells in seronegative PR patients with active flares compared with healthy controls (P < 0.0001 for both cell subset comparisons). Gene enrichment analyses of RNA-sequencing data from sorted CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells showed involvement of the inflammatory/stress response, phagocytosis, and regulation of apoptosis functional pathways. Up-regulated expression of CXCL16 and IL10RA was observed in monocytes from PR patients. Up-regulation of PFKFB3, DDIT4, and TGFB1, and down-regulation of PDIA6 were found in monocytes and lymphocytes from PR patients with active flares and PR patients in intercritical periods. Plasma levels of S100A8/A9 and interleukin-1β were elevated in PR patients. Whole-exome sequencing revealed novel polygenic mutations in HACL1, KDM5A, RASAL1, HAVCR2, PRDM9, MBOAT4, and JRKL.

CONCLUSION

In seronegative PR patients, we identified a distinct CD14+CD11b+CD36+ cell subset that can induce an inflammatory response under stress and exert antiinflammatory effects after phagocytosis of apoptotic cells, and a CD4+CD25-CD69+ T cell subset with pro- and antiinflammatory properties. Individuals with genetic mutations involving epigenetic modification, potentiation and resolution of stress-induced inflammation/apoptosis, and a dysregulated endoplasmic reticulum stress response could be predisposed to seronegative PR.

Endoplasmic reticulum stress mediates the myeloid-derived immune suppression associated with cancer and infectious disease

Myeloid-derived suppressor cells (MDSCs), which are immature heterogeneous bone marrow cells, have been described as potent immune regulators in human and murine cancer models. The distribution of MDSCs varies across organs and is divided into three subpopulations: granulocytic MDSCs or polymorphonuclear MDSCs (G-MDSCs or PMN-MDSCs), monocytic MDSCs (M-MDSCs), as well as a recently identified early precursor MDSC (eMDSCs) in humans. Activated MDSCs induce the inactivation of NK cells, CD4+, and CD8+ T cells through a variety of mechanisms, thus promoting the formation of tumor immunosuppressive microenvironment. ER stress plays an important protecting role in the survival of MDSC, which aggravates the immunosuppression in tumors. In addition, ferroptosis can promote an anti-tumor immune response by reversing the immunosuppressive microenvironment. This review summarizes immune suppression by MDSCs with a focus on the role of endoplasmic reticulum stress-mediated immune suppression in cancer and infectious disease, in particular leprosy and tuberculosis.

Regulation of secretory pathway kinase or kinase-like proteins in human cancers

Secretory pathway kinase or kinase-like proteins (SPKKPs) are effective in the lumen of the endoplasmic reticulum (ER), Golgi apparatus (GA), and extracellular space. These proteins are involved in secretory signaling pathways and are distinctive from typical protein kinases. Various reports have shown that SPKKPs regulate the tumorigenesis and progression of human cancer via the phosphorylation of various substrates, which is essential in physiological and pathological processes. Emerging evidence has revealed that the expression of SPKKPs in human cancers is regulated by multiple factors. This review summarizes the current understanding of the contribution of SPKKPs in tumorigenesis and the progression of immunity. With the epidemic trend of immunotherapy, targeting SPKKPs may be a novel approach to anticancer therapy. This study briefly discusses the recent advances regarding SPKKPs.

Geraniol-Mediated Suppression of Endoplasmic Reticulum Stress Protects against Cerebral Ischemia-Reperfusion Injury via the PERK-ATF4-CHOP Pathway

Endoplasmic reticulum (ER) stress plays an important role in cerebral ischemia-reperfusion injury (CIRI). Geraniol has antioxidant, antibacterial, and anti-inflammatory activities. Studies have shown that geraniol has a protective effect against CIRI in rats, but the exact mechanism is unclear. Purpose: The aim of this study was to investigate the protective mechanism of geraniol against CIRI. We established a middle cerebral artery occlusion reperfusion model in rats and a PC12 cell oxygen-glucose deprivation/reoxygenation (OGD/R) model to observe the neuroprotective effects of geraniol. Neurological scoring, 2,3,5-triphenyltetrazolium chloride staining, and hematoxylin and eosin staining were used to evaluate the neuroprotective effects of geraniol against CIRI. ER-stress-related and apoptosis-related protein expression was detected via Western blotting and immunofluorescence. Apoptosis was also detected via TUNEL assays and flow cytometry. The fluorescent detection of intracellular calcium was achieved using fluorescent calcium-binding dyes, and transmission electron microscopy was used to assess the neuronal ultrastructure. Geraniol effectively attenuated cerebral infarction and pathological injury after CIRI, had a protective effect against CIRI, significantly reduced the expression of the ER-stress-related proteins P-PERK, ATF4, CHOP, and GRP78 and the pro-apoptotic protein BAX, increased the expression of the anti-apoptotic protein BCL-2, and reduced the occurrence of apoptosis. In the OGD/R model in PC12 cells, the protective effect of geraniol was the same as that in vivo. Our results suggest that geraniol has a protective effect against ischemic stroke by a mechanism possibly related to ER stress via the PERK-ATF4-CHOP pathway.

Transcriptome signatures preceding the induction of anti-stalk antibodies elicited after universal influenza vaccination

A phase 1 clinical trial to test the immunogenicity of a chimeric group 1 HA (cHA) universal influenza virus vaccine targeting the conserved stalk domain of the hemagglutinin of influenza viruses was carried out. Vaccination with adjuvanted-inactivated vaccines induced high anti-stalk antibody titers. We sought to identify gene expression signatures that correlate with such induction. Messenger-RNA sequencing in whole blood was performed on the peripheral blood of 53 vaccinees. We generated longitudinal data on the peripheral blood of 53 volunteers, at early (days 3 and 7) and late (28 days) time points after priming and boosting with cHAs. Differentially expressed gene analysis showed no differences between placebo and live-attenuated vaccine groups. However, an upregulation of genes involved in innate immune responses and type I interferon signaling was found at day 3 after vaccination with inactivated adjuvanted formulations. Cell type deconvolution analysis revealed a significant enrichment for monocyte markers and different subsets of dendritic cells as mediators for optimal B cell responses and significant increase of anti-stalk antibodies in sera. A significant upregulation of immunoglobulin-related genes was only observed after administration of adjuvanted vaccines (either as primer or booster) with specific induction of anti-stalk IGVH1-69. This approach informed of specific immune signatures that correlate with robust anti-stalk antibody responses, while also helping to understand the regulation of gene expression induced by cHA proteins under different vaccine regimens.

KIRA8 attenuates non-alcoholic steatohepatitis through inhibition of the IRE1α/XBP1 signalling pathway

Endoplasmic reticulum (ER) stress is enhanced in non-alcoholic steatohepatitis (NASH). Among three signalling pathways, the IRE1α/XBP1 signalling pathway is strongly implicated in the pathogenesis of NASH but its significance is still largely uncharacterised. In this report, we constructed a hepatocyte-specific XBP1-Luciferase knock-in mouse model that allows in vivo monitoring of the IRE1α/XBP1 activity in hepatocytes. Using this mouse model, we found that IRE1α/XBP1 was activated within hepatocytes during the pathogenesis of NASH. Significantly, a specific IRE1α kinase-inhibiting RNase attenuator, KIRA8, attenuated NASH in mice. In conclusion, our hepatocyte-specific XBP1 splicing reporter mouse represents a valid model for research and drug development of NASH, which showed that the IRE1α-induced XBP splicing is potentiated in hepatocytes during pathogenesis of NASH. Furthermore, we carried out the proof-of-concept study to demonstrate that the allosteric IRE1α RNase inhibitor serves as a promising therapeutic agent for the treatment of NASH.

Investigating a Genetic Link Between Alzheimer's Disease and CADASIL-Related Cerebral Small Vessel Disease

Monogenic forms of Alzheimer's disease (AD) have been identified through mutations in genes such as APP, PSEN1, and PSEN2, whilst other genetic markers such as the APOE ε carrier allele status have been shown to increase the likelihood of having the disease. Mutations in these genes are not limited to AD, as APP mutations can also cause an amyloid form of cerebral small vessel disease (CSVD) known as cerebral amyloid angiopathy, whilst PSEN1 and PSEN2 are involved in NOTCH3 signalling, a process known to be dysregulated in the monogenic CSVD, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The overlap between AD genes and causes of CSVD led to the hypothesis that mutations in other genes within the PANTHER AD-presenilin pathway may be novel causes of CSVD in a cohort of clinically suspicious CADASIL patients without a pathogenic NOTCH3 mutation. To investigate this, whole exome sequencing was performed on 50 suspected CADASIL patients with no NOTCH3 mutations, and a targeted gene analysis was completed on the PANTHER. ERN1 was identified as a novel candidate CSVD gene following predicted pathogenic gene mutation analysis. Rare variant burden testing failed to identify an association with any gene; however, it did show a nominally significant link with ERN1 and TRPC3. This study provides evidence to support a genetic overlap between CSVD and Alzheimer's disease.

Dissecting the Immunological Profiles in NSD3-Amplified LUSC through Integrative Multi-Scale Analyses

Simple Summary

Although cancer immunotherapy has become a “game changer” in treating LUSC patients, challenges still prevail due to the heterogeneous response and insufficient predictive biomarkers. Recently, NSD3, a neighbor gene of FGFR1, was identified as a key genetic driver of LUSC tumorigenesis. While previous studies have reported the relevance of NSD3 in innate antiviral immunity, the association of NSD3 with the TIME remains an open question requiring further investigation. We first show that NSD3 gene amplification is associated with an immune-desert phenotype and correlated with a worse immunotherapy outcome. Further molecular characterizations pinpoint that the high activity of UPR signaling might be a pivotal mediator for the non-inflamed TME phenotype of NSD3-amplified LUSC. Concordantly, the pharmaco-transcriptomic correlation analysis indicated that the intervention of UPR signaling could be a promising synthetic lethality target for NSD3-amplified LUSC. Our findings reveal a previously unappreciated immunological role for NSD3 in LUSC pathobiology and provide therapeutic rationales for this daunting disease.

Abstract

The histone H3 lysine 36 (H3K36) methyltransferase NSD3, a neighboring gene of FGFR1, has been identified as a critical genetic driver of lung squamous cell carcinoma (LUSC). However, the molecular characteristics, especially the immunological roles of NSD3 in driving carcinogenesis, are poorly understood. In this study, we systematically integrated multi-omics data (e.g., genome, transcriptome, proteome, and TMA array) to dissect the immunological profiles in NSD3-amplified LUSC. Next, pharmaco-transcriptomic correlation analysis was implemented to identify the molecular underpinnings and therapeutic vulnerabilities in LUSC. We revealed that NSD3-amplified LUSC presents a non-inflamed tumor immune microenvironment (TIME) state in multiple independent LUSC patient cohorts. Predictably, elevated NSD3 expression was correlated with a worse immunotherapy outcome. Further molecular characterizations revealed that the high activity of unfolded protein response (UPR) signaling might be a pivotal mediator for the non-immunogenic phenotype of NSD3-amplified LUSC. Concordantly, we showed that NSD3-amplified LUSCs exhibited a more sensitive phenotype to compounds targeting UPR branches than the wild-type group. In brief, our multi-level analyses point to a previously unappreciated immunological role for NSD3 and provide therapeutic rationales for NSD3-amplified squamous lung cancer.

Understanding the Function and Mechanism of Zebrafish Tmem39b in Regulating Cold Resistance

Autophagy and endoplasmic reticulum (ER) stress response are among the key pathways regulating cold resistance of fish through eliminating damaged cellular components and facilitating the restoration of cell homeostasis upon exposure to acute cold stress. The transmembrane protein 39A (TMEM39A) was reported to regulate both autophagy and ER stress response, but its vertebrate-specific paralog, the transmembrane protein 39B (TMEM39B), has not been characterized. In the current study, we generate tmem39b-knockout zebrafish lines and characterize their survival ability under acute cold stress. We observed that the dysfunction of Tmem39b remarkably decreased the cold resilience of both the larval and adult zebrafish. Gene transcription in the larvae exposed to cold stress and rewarming were characterized by RNA sequencing (RNA-seq) to explore the mechanisms underlying functions of Tmem39b in regulating cold resistance. The results indicate that the deficiency of Tmem39b attenuates the up-regulation of both cold- and rewarming-induced genes. The cold-induced transcription factor genes bif1.2, fosab, and egr1, and the rewarming-activated immune genes c3a.3, il11a, and sting1 are the representatives influenced by Tmem39b dysfunction. However, the loss of tmem39b has little effect on the transcription of the ER stress response- and autophagy-related genes. The measurements of the phosphorylated H2A histone family member X (at Ser 139, abbreviated as γH2AX) demonstrate that zebrafish Tmem39b protects the cells against DNA damage caused by exposure to the cold-warming stress and facilitates tissue damage repair during the recovery phase. The gene modules underlying the functions of Tmem39b in zebrafish are highly enriched in biological processes associated with immune response. The dysfunction of Tmem39b also attenuates the up-regulation of tissue C-reactive protein (CRP) content upon rewarming. Together, our data shed new light on the function and mechanism of Tmem39b in regulating the cold resistance of fish.

The Role of 4-Phenylbutyric Acid in Gut Microbial Dysbiosis in a Mouse Model of Simulated Microgravity

The altered gut microbes of astronauts during space travel may contribute to health issues after their return to Earth. Previously, an association between the elevated endoplasmic reticulum (ER) stress and gut microbial dysbiosis has been described. Herein, we induced gut microbial changes in mice under a simulated microgravity environment in an established model of hindlimb unloaded (HU) mice. The intestinal metabolomic profiles under microgravity conditions using the HU model were examined, along with the potential role of 4-phenylbutyric acid (4-PBA), a potent ER stress inhibitor. For a microgravity environment, the mice were suspended in special cages individually for three weeks. Mice were sacrificed, and gut dissections were performed, followed by amplicon sequencing analysis of bacterial species via DNA extraction and 16S rRNA analysis. The results indicate that the gut bacterial communities of mice differed under gravity and microgravity conditions. Principal component analyses revealed differences in the bacterial community structure in all groups. Around 434 operational taxonomic units (OTUs) were specific to mice seen in controls, while 620 OTUs were specific to HU mice. Additionally, 321 bacterial OTUs were specific to HU mice treated with 4-PBA. When the relative abundance of taxa was analyzed, Bacteroidetes dominated the gut of control and HU mice treated with 4-PBA.. In contrast, the untreated HU mice were dominated by Firmicutes. At the genus level, a reduction in beneficial species of Akkermansia and Lactobacillus was observed in HU but not the unloaded–treated and control mice. Furthermore, an increase in the relative abundance of Lachnospiraceae and Enterorhabdus, associated with inflammation, was observed in HUmice but not in controls and unloaded-treated mice. Following treatment with 4-PBA, the ratio of Firmicutes to Bacteroidetes was restored in unloaded–treated mice, comparable to controls. Of note, beneficial microbes such as Akkermansia and Lactobacillus were observed in unloaded–treated mice but not or in lesser relative abundance in HU mice. Nonetheless, microbial diversity was reduced in unloaded–treated mice compared to controls, and future studies are needed to mitigate this finding. These may comprise the addition of pre-/pro- and postbiotic species in the diet to increase microbial diversity. Overall, the findings suggest that 4-PBA, a potent ER stress inhibitor, may have therapeutic value in treating patients on prolonged bed rest or astronauts during spaceflight.

Gold Nanorods Induce Endoplasmic Reticulum Stress and Autocrine Inflammatory Activation in Human Neutrophils

Gold nanorods (AuNRs) are promising agents for diverse biomedical applications such as drug and gene delivery, bioimaging, and cancer treatment. Upon in vivo application, AuNRs quickly interact with cells of the immune system. On the basis of their strong intrinsic phagocytic activity, polymorphonuclear neutrophils (PMNs) are specifically equipped for the uptake of particulate materials such as AuNRs. Therefore, understanding the interaction of AuNRs with PMNs is key for the development of safe and efficient therapeutic applications. In this study, we investigated the uptake, intracellular processing, and cell biological response induced by AuNRs in PMNs. We show that uptake of AuNRs mainly occurs via phagocytosis and macropinocytosis with rapid deposition of AuNRs in endosomes within 5 min. Within 60 min, AuNR uptake induced an unfolded protein response (UPR) along with induction of inositol-requiring enzyme 1 α (IREα) and features of endoplasmic reticulum (ER) stress. This early response was followed by a pro-inflammatory autocrine activation loop that involves LOX1 upregulation on the cell surface and increased secretion of IL8 and MMP9. Our study provides comprehensive mechanistic insight into the interaction of AuNRs with immune cells and suggests potential targets to limit the unwanted immunopathological activation of PMNs during application of AuNRs.

Neddylation tunes peripheral blood mononuclear cells immune response in COVID-19 patients

The COVID-19 pandemic caused by SARS-CoV-2 has reached 5.5 million deaths worldwide, generating a huge impact globally. This highly contagious viral infection produces a severe acute respiratory syndrome that includes cough, mucus, fever and pneumonia. Likewise, many hospitalized patients develop severe pneumonia associated with acute respiratory distress syndrome (ARDS), along an exacerbated and uncontrolled systemic inflammation that in some cases induces a fatal cytokine storm. Although vaccines clearly have had a beneficial effect, there is still a high percentage of unprotected patients that develop the pathology, due to an ineffective immune response. Therefore, a thorough understanding of the modulatory mechanisms that regulate the response to SARS-CoV-2 is crucial to find effective therapeutic alternatives. Previous studies describe the relevance of Neddylation in the activation of the immune system and its implications in viral infection. In this context, the present study postulates Neddylation, a reversible ubiquitin-like post-translational modification of proteins that control their stability, localization and activity, as a key regulator in the immune response against SARS-CoV-2. For the first time, we describe an increase in global neddylation levels in COVID-19 in the serum of patients, which is particularly associated with the early response to infection. In addition, the results showed that overactivation of neddylation controls activation, proliferation, and response of peripheral blood mononuclear cells (PBMCs) isolated from COVID-19 patients. Inhibition of neddylation, and the subsequent avoidance of activated PBMCs, reduces cytokine production, mainly IL-6 and MCP-1 and induce proteome modulation, being a critical mechanism and a potential approach to immunomodulate COVID-19 patients.

Translational Control by 4E-BP1/2 Suppressor Proteins Regulates Mitochondrial Biosynthesis and Function during CD8+ T Cell Proliferation

CD8⁺ T cell proliferation and differentiation into effector and memory states are high-energy processes associated with changes in cellular metabolism. CD28-mediated costimulation of T cells activates the PI3K/AKT/mammalian target of rapamycin signaling pathway and induces eukaryotic translation initiation factor 4E-dependent translation through the derepression by 4E-BP1 and 4E-BP2. In this study, we demonstrate that 4E-BP1/2 proteins are required for optimum proliferation of mouse CD8⁺ T cells and the development of an antiviral effector function. We show that translation of genes encoding mitochondrial biogenesis is impaired in T cells derived from 4E-BP1/2-deficient mice. Our findings demonstrate an unanticipated role for 4E-BPs in regulating a metabolic program that is required for cell growth and biosynthesis during the early stages of CD8⁺ T cell expansion.

Mutations of γCOP Gene Disturb Drosophila melanogaster Innate Immune Response to Pseudomonas aeruginosa

Drosophila melanogaster (the fruit fly) is a valuable experimental platform for modeling host–pathogen interactions. It is also commonly used to define innate immunity pathways and to understand the mechanisms of both host tolerance to commensal microbiota and response to pathogenic agents. Herein, we investigate how the host response to bacterial infection is mirrored in the expression of genes of Imd and Toll pathways when D. melanogaster strains with different γCOP genetic backgrounds are infected with Pseudomonas aeruginosa ATCC 27853. Using microarray technology, we have interrogated the whole-body transcriptome of infected versus uninfected fruit fly males with three specific genotypes, namely wild-type Oregon, γCOP^S057302/TM6B and γCOP^14a/γCOP^14a. While the expression of genes pertaining to Imd and Toll is not significantly modulated by P. aeruginosa infection in Oregon males, many of the components of these cascades are up- or downregulated in both infected and uninfected γCOP^S057302/TM6B and γCOP^14a/γCOP^14a males. Thus, our results suggest that a γCOP genetic background modulates the gene expression profiles of Imd and Toll cascades involved in the innate immune response of D. melanogaster, inducing the occurrence of immunological dysfunctions in γCOP mutants.

Empagliflozin alleviates endoplasmic reticulum stress and augments autophagy in rotenone-induced Parkinson's disease in rats: Targeting the GRP78/PERK/eIF2α/CHOP pathway and miR-211-5p

Empagliflozin, a selective sodium-glucose co-transporter-2 inhibitor, has been demonstrated to provide additional non-glycemic benefits, including neuroprotection. Endoplasmic reticulum (ER) stress is a key player in neurodegeneration and occurs at the crossroads of other pathologic mechanisms; however, its role in the pathogenesis of Parkinson's disease (PD) is still elusive. miR-211-5p regulates neuronal differentiation and viability and was predicted to target CHOP, a downstream effector in the ER stress pathway. For the first time, this study investigated the possible neuroprotective effect of empagliflozin in a rotenone-induced rat model of PD from the perspective of ER stress. Rotenone (1.5 mg/kg) was administered subcutaneously every other day for 3 weeks. Meanwhile, the treated group received empagliflozin 10 mg/kg/day orally for 15 consecutive days post-PD induction. On the molecular level, the ER stress pathway components; GRP78, total and phosphorylated PERK, eIF2α and CHOP, along with miR-211-5p expression were upregulated in the striatum of rotenone-injected rats. Concurrently, the untreated rats showed elevated striatal α-synuclein levels along with diminished autophagy and the proteasome system as evidenced by reduced beclin-1 protein and ELF2/NERF mRNA expression levels. The rotenone-induced striatal oxidative stress and neuroinflammation were expressed by reduced catalase activity and elevated interleukin (IL)-1β levels. miR-211-5p was positively correlated with PERK/eIF2α/CHOP, IL-1β and α-synuclein, while negatively correlated with ELF2/NERF, beclin-1 and catalase activity. Empagliflozin treatment showed a restorative effect on all biochemical alterations and improved the motor function of rats tested by open field, grip strength and footprint gait analysis. In the histopathological examination, empagliflozin increased the intact neuron count and attenuated astrogliosis and microgliosis by reducing the glial fibrillary protein and ionized calcium-binding adaptor protein 1 immunostaining. Conclusively, these results emphasize the neurotherapeutic impact of empagliflozin in PD by moderating the GRP78/PERK/eIF2α/CHOP ER stress pathway, downregulating miR-211-5p, resolving oxidative stress, lessening astrocyte/microglial activation and neuroinflammation, along with augmenting autophagy.

An Updated View of the Importance of Vesicular Trafficking and Transport and Their Role in Immune-Mediated Diseases: Potential Therapeutic Interventions

Cellular trafficking is the set of processes of distributing different macromolecules by the cell. This process is highly regulated in cells, involving a system of organelles (endomembranous system), among which are a great variety of vesicles that can be secreted from the cell, giving rise to different types of extracellular vesicles (EVs) that can be captured by other cells to modulate their function. The cells of the immune system are especially sensitive to this cellular traffic, producing and releasing different classes of EVs, especially in disease states. There is growing interest in this field due to the therapeutic and translational possibilities it offers. Different ways of taking advantage of the understanding of cell trafficking and EVs are being investigated, and their use as biomarkers or therapeutic targets is being investigated. The objective of this review is to collect the latest results and knowledge in this area with a specific focus on immune-mediated diseases. Although some promising results have been obtained, further knowledge is still needed, at both the basic and translational levels, to understand and modulate cellular traffic and EVs for better clinical management of these patients.

Carbon Monoxide Activates PERK-Regulated Autophagy to Induce Immunometabolic Reprogramming and Boost Antitumor T-cell Function

Mitochondria and endoplasmic reticulum (ER) share structural and functional networks and activate well-orchestrated signaling processes to shape cells' fate and function. While persistent ER stress (ERS) response leads to mitochondrial collapse, moderate ERS promotes mitochondrial function. Strategies to boost antitumor T-cell function by targeting ER-mitochondria cross-talk have not yet been exploited. Here, we used carbon monoxide (CO), a short-lived gaseous molecule, to test whether engaging moderate ERS conditions can improve mitochondrial and antitumor functions in T cells. In melanoma antigen-specific T cells, CO-induced transient activation of ERS sensor protein kinase R-like endoplasmic reticulum kinase (PERK) significantly increased antitumor T-cell function. Furthermore, CO-induced PERK activation temporarily halted protein translation and induced protective autophagy, including mitophagy. The use of LC3-GFP enabled differentiation between the cells that prepare themselves to undergo active autophagy (LC3-GFPpos) and those that fail to enter the process (LC3-GFPneg). LC3-GFPpos T cells showed strong antitumor potential, whereas LC3-GFPneg cells exhibited a T regulatory-like phenotype, harbored dysfunctional mitochondria, and accumulated abnormal metabolite content. These anomalous ratios of metabolites rendered the cells with a hypermethylated state and distinct epigenetic profile, limiting their antitumor activity. Overall, this study shows that ERS-activated autophagy pathways modify the mitochondrial function and epigenetically reprogram T cells toward a superior antitumor phenotype to achieve robust tumor control.

SIGNIFICANCE

Transient activation of ER stress with carbon monoxide drives mitochondrial biogenesis and protective autophagy that elicits superior antitumor T-cell function, revealing an approach to improving adoptive cell efficacy therapy.

Endoplasmic reticulum stress in airway hyperresponsiveness

Airway hyperresponsiveness(AHR) is a major clinical phenomenon in lung diseases (asthma, COPD and pulmonary fibrosis) and not only a high-risk factor for perioperative airway spasm leading to hypoxaemia, haemodynamic instability and even "silent lung", but also a potential risk for increased mortality from underlying diseases (e.g. asthma, COPD). Airway reactivity is closely linked to airway inflammation, remodelling and increased mucus secretion, and endoplasmic reticulum stress is an important mechanism for the development of these pathologies. This review, therefore, focuses on the effects of endoplasmic reticulum stress on the immune cells involved in airway hyperreactivity (epithelial cells, dendritic cells, eosinophils and neutrophils) in inflammation and mucus & sputum secretion; and on the differentiation and remodelling of airway smooth muscle cells and epithelial cells. The aim is to clarify the mechanisms associated with endoplasmic reticulum stress in airway hyperresponsiveness and to find new ideas and methods for the prevention of airway hyperresponsiveness in the perioperative period.

A Review of the Effects of Cervical Cancer Standard Treatment on Immune Parameters in Peripheral Blood, Tumor Draining Lymph Nodes, and Local Tumor Microenvironment

Cervical cancer remains a public health concern despite all the efforts to implement vaccination and screening programs. Conventional treatment for locally advanced cervical cancer consists of surgery, radiotherapy (with concurrent brachytherapy), combined with chemotherapy, or hyperthermia. The response rate to combination approaches involving immunomodulatory agents and conventional treatment modalities have been explored but remain dismal in patients with locally advanced disease. Studies exploring the immunological effects exerted by combination treatment modalities at the different levels of the immune system (peripheral blood (PB), tumor-draining lymph nodes (TDLN), and the local tumor microenvironment (TME)) are scarce. In this systemic review, we aim to define immunomodulatory and immunosuppressive effects induced by conventional treatment in cervical cancer patients to identify the optimal time point for immunotherapy administration. Radiotherapy (RT) and chemoradiation (CRT) induce an immunosuppressive state characterized by a long-lasting reduction in peripheral CD3, CD4, CD8 T cells and NK cells. At the TDLN level, CRT induced a reduction in Nrp1+Treg stability and number, naïve CD4 and CD8 T cell numbers, and an accompanying increase in IFNγ-producing CD4 helper T cells, CD8 T cells, and NK cells. Potentiation of the T-cell anti-tumor response was particularly observed in patients receiving low irradiation dosage. At the level of the TME, CRT induced a rebound effect characterized by a reduction of the T-cell anti-tumor response followed by stable radioresistant OX40 and FoxP3 Treg cell numbers. However, the effects induced by CRT were very heterogeneous across studies. Neoadjuvant chemotherapy (NACT) containing both paclitaxel and cisplatin induced a reduction in stromal FoxP3 Treg numbers and an increase in stromal and intratumoral CD8 T cells. Both CRT and NACT induced an increase in PD-L1 expression. Although there was no association between pre-treatment PD-L1 expression and treatment outcome, the data hint at an association with pro-inflammatory immune signatures, overall and disease-specific survival (OS, DSS). When considering NACT, we propose that posterior immunotherapy might further reduce immunosuppression and chemoresistance. This review points at differential effects induced by conventional treatment modalities at different immune compartments, thus, the compartmentalization of the immune responses as well as individual patient's treatment plans should be carefully considered when designing immunotherapy treatment regimens.