Impact of occupational noise exposure on the hearing level in hospital staffs: a longitudinal study.

The study aimed to evaluate the impact of occupational noise on hearing loss among healthcare workers using audiometry. A longitudinal study was conducted with a six-month follow-up period in a hospital with 21 participants, divided into high-noise-exposure (HNE) and low-noise-exposure (LNE) groups. Mean noise levels were higher in the HNE group (70.4 ± 4.5 dBA), and hearing loss was measured using pure-tone audiometry at baseline and follow-up. The HNE group had significantly higher mean threshold levels at frequencies of 0.25 kHz, 0.5 kHz, 4.0 kHz, and an average of 0.5, 1, 2, and 4 kHz (all p-values < 0.05) after the follow-up period. After adjusting for confounding factors, the HNE group had significantly higher hearing loss levels at 0.25 kHz, 0.5 kHz, and average frequencies of 0.5, 1, 2, and 4 kHz compared to the LNE group at the second measurement. Occupational noise levels above 65 dBA over six months were found to cause significant threshold changes at frequencies of 0.25 kHz, 0.5 kHz, and an average of 0.5-4.0 kHz. This study highlights the risk of noise-induced hearing loss among healthcare workers and emphasizes the importance of implementing effective hearing conservation programs in the workplace. Regular monitoring and assessment of noise levels and hearing ability, along with proper use of personal protective equipment, are crucial steps in mitigating the impact of occupational noise exposure on the hearing health of healthcare workers.

Endoplasmic reticulum stress enhances the expression of TLR3-induced TSLP by airway epithelium.

Thymic stromal lymphopoietin (TSLP) is an epithelial-derived pleiotropic cytokine that regulates T-helper 2 (Th2) immune responses in the lung and plays a major role in severe uncontrolled asthma. Emerging evidence suggests a role for endoplasmic reticulum (ER) stress in the pathogenesis of asthma. In this study, we determined if ER stress and the unfolded protein response (UPR) signaling are involved in TSLP induction in the airway epithelium. For this, we treated human bronchial epithelial basal cells and differentiated primary bronchial epithelial cells with ER stress inducers and the TSLP mRNA and protein expression was determined. A series of siRNA gene knockdown experiments were conducted to determine the ER stress-induced TSLP signaling pathways. cDNA collected from asthmatic bronchial biopsies was used to determine the gene correlation between ER stress and TSLP. Our results show that ER stress signaling induces TSLP mRNA expression via the PERK-C/EBP homologous protein (CHOP) signaling pathway. AP-1 transcription factor is important in regulating this ER stress-induced TSLP mRNA induction, though ER stress alone cannot induce TSLP protein production. However, ER stress significantly enhances TLR3-induced TSLP protein secretion in the airway epithelium. TSLP and ER stress (PERK) mRNA expression positively correlates in bronchial biopsies from participants with asthma, particularly in neutrophilic asthma. In conclusion, these results suggest that ER stress primes TSLP that is then enhanced further upon TLR3 activation, which may induce severe asthma exacerbations. Targeting ER stress using pharmacological interventions may provide novel therapeutics for severe uncontrolled asthma.NEW & NOTEWORTHY TSLP is an epithelial-derived cytokine and a key regulator in the pathogenesis of severe uncontrolled asthma. We demonstrate a novel mechanism by which endoplasmic reticulum stress signaling upregulates airway epithelial TSLP mRNA expression via the PERK-CHOP signaling pathway and enhances TLR3-mediated TSLP protein secretion.

The palmitoylation of gasdermin D directs its membrane translocation and pore formation during pyroptosis.

Plasma membrane perforation elicited by caspase cleavage of the gasdermin D (GSDMD) N-terminal domain (GSDMD-NT) triggers pyroptosis. The mechanisms underlying GSDMD membrane translocation and pore formation are not fully understood. Here, using a proteomic approach, we identified fatty acid synthase (FASN) as a GSDMD-binding partner. S-palmitoylation of GSDMD at Cys191/Cys192 (human/mouse), catalyzed by palmitoyl acyltransferases ZDHHC5 and ZDHHC9 and facilitated by reactive oxygen species (ROS), directly mediated membrane translocation of GSDMD-NT but not full-length GSDMD (GSDMD-FL). Palmitoylation of GSDMD-FL could be induced before inflammasome activation by stimuli such as lipopolysaccharide (LPS), consequently serving as an essential molecular event in macrophage priming. Inhibition of GSDMD palmitoylation suppressed macrophage pyroptosis and IL-1ß release, mitigated organ damage, and enhanced the survival of septic mice. Thus, GSDMD-NT palmitoylation is a key regulatory mechanism controlling GSDMD membrane localization and activation, which may offer an additional target for modulating immune activity in infectious and inflammatory diseases.

Gasdermin E dictates inflammatory responses by controlling the mode of neutrophil death.

Both lytic and apoptotic cell death remove senescent and damaged cells in living organisms. However, they elicit contrasting pro- and anti-inflammatory responses, respectively. The precise cellular mechanism that governs the choice between these two modes of death remains incompletely understood. Here we identify Gasdermin E (GSDME) as a master switch for neutrophil lytic pyroptotic death. The tightly regulated GSDME cleavage and activation in aging neutrophils are mediated by proteinase-3 and caspase-3, leading to pyroptosis. GSDME deficiency does not alter neutrophil overall survival rate; instead, it specifically precludes pyroptosis and skews neutrophil death towards apoptosis, thereby attenuating inflammatory responses due to augmented efferocytosis of apoptotic neutrophils by macrophages. In a clinically relevant acid-aspiration-induced lung injury model, neutrophil-specific deletion of GSDME reduces pulmonary inflammation, facilitates inflammation resolution, and alleviates lung injury. Thus, by controlling the mode of neutrophil death, GSDME dictates host inflammatory outcomes, providing a potential therapeutic target for infectious and inflammatory diseases.

TLR7 promotes smoke-induced experimental lung damage through the activity of mast cell tryptase.

Toll-like receptor 7 (TLR7) is known for eliciting immunity against single-stranded RNA viruses, and is increased in both human and cigarette smoke (CS)-induced, experimental chronic obstructive pulmonary disease (COPD). Here we show that the severity of CS-induced emphysema and COPD is reduced in TLR7-deficient mice, while inhalation of imiquimod, a TLR7-agonist, induces emphysema without CS exposure. This imiquimod-induced emphysema is reduced in mice deficient in mast cell protease-6, or when wild-type mice are treated with the mast cell stabilizer, cromolyn. Furthermore, therapeutic treatment with anti-TLR7 monoclonal antibody suppresses CS-induced emphysema, experimental COPD and accumulation of pulmonary mast cells in mice. Lastly, TLR7 mRNA is increased in pre-existing datasets from patients with COPD, while TLR7+ mast cells are increased in COPD lungs and associated with severity of COPD. Our results thus support roles for TLR7 in mediating emphysema and COPD through mast cell activity, and may implicate TLR7 as a potential therapeutic target.

Tinnitus as a Potential Risk Factor for Uveitis: A 14-Year Nationwide Population-Based Cohort Study in Taiwan.

BACKGROUND: Tinnitus and uveitis have shared commonality in pathophysiology in terms of autoimmunity. However, no studies that have linked any association between the conditions of tinnitus and uveitis. METHODS: This is a retrospective study conducted from the Taiwan National Health Insurance database in order to investigate whether tinnitus patients are at increased risk of uveitis. Patients newly diagnosed with tinnitus between 2001 and 2014 were recruited and followed up until 2018. The endpoint of interest was a diagnosis of uveitis. RESULTS: A total of 31,034 tinnitus patients and 124,136 matched comparisons were analyzed. Tinnitus patients were found to have a significantly higher cumulative incidence for uveitis than those without the diagnosis of tinnitus with incidence rate of 1.68 (95% CI 1.55-1.82) per 10 000 person-months for tinnitus group and 1.48 (95% CI 1.42-1.54) per 10 000 person-months for non-tinnitus group. CONCLUSION: Tinnitus patients were found to have increased risk of developing uveitis.

Method for Visualization of Emergency Granulopoiesis in the Zebrafish Embryo.

Emergency granulopoiesis (EG) is a response to severe inflammation in which increased neutrophils are generated in the hematopoietic tissue. Photolabeling is utilized to distinguish newly developed neutrophils from existing neutrophils. However, this technique requires a strong laser line and labels subsets of the existing neutrophils. Here we create a transgenic zebrafish line that expresses a time-dependent switch from green fluorescent protein (GFP) to red fluorescent protein (RFP) in neutrophils, which allows quantification of EG using simple GFP/RFP ratiometric imaging.

Neutrophil Lifespan Extension with CLON-G and an In Vitro Spontaneous Death Assay.

The average lifespan of a neutrophil is less than 24 h, which limits basic research on neutrophils and the application of neutrophil studies. Our previous research indicated that multiple pathways could mediate the spontaneous death of neutrophils. A cocktail was developed by simultaneously targeting these pathways, caspases-lysosomal membrane permeabilization-oxidant-necroptosis inhibition plus granulocyte colony-stimulating factor (CLON-G), which prolonged the neutrophil lifespan to greater than 5 days without significantly compromising the neutrophil function. Concurrently, a reliable and stable protocol for assessing and evaluating neutrophil death was also developed. In this work, we show that CLON-G can prolong the neutrophil lifespan in vitro to more than 5 days, and we exhibit the lengthening of the neutrophil lifespan with FACS and confocal fluorescence microscopy. This report introduces procedures for the preparation of CLON-G and showcases an in vitro spontaneous death assay of neutrophils, which can be used for the study of neutrophils and for subsequently interrogating neutrophil death, thus providing a reliable resource for the neutrophil community.

Ultrawide-Field Optical Coherence Tomography in Transvitreal and Subretinal Fibrinoid Syndrome: A Case Report.

We report a case of fibrinoid reaction after diabetic vitrectomy surgery. Our case report describes a male patient with severe fibrinoid reaction with both intravitreal fibrin bands and subretinal fibrin and fluid following vitrectomy for diabetic retinopathy. He was managed initially with posterior subtenon and suprachoroidal injection of triamcinolone as well as intravitreal injection of tissue plasminogen activator (TPA). Fluid-air exchange and air-fluid exchange were also performed to remove the fibrin degradation product. 1 millimeter of air tamponade was placed in the vitreous cavity to displace the remaining subretinal fibrin. During this patient's follow-up, the patient's OCT including ultrawide-field OCT showed transvitreal fibrin bands, subretinal fibrin, as well as subretinal fluid in the right eye. The degradation of intravitreal fibrin bands as well as decrease in subretinal fluid were noted 2 days after intravitreal TPA and suprachoroidal injection of triamcinolone acetonide. The subretinal fibrin was partially reabsorbed and displaced after repeated injection of TPA and air tamponade placement 1 week later. Subsequent follow-up showed complete resolution of the subretinal fibrin and subretinal fluid as well as improved visual acuity. In summary, we describe a case of fibrinoid reaction after vitrectomy for diabetic retinopathy which was successfully treated. Wide-field OCT may also be used to assist in the recognition of this phenomenon.

Optical Coherence Tomography Biomarkers in Predicting Treatment Outcomes of Diabetic Macular Edema after Ranibizumab Injections.

Background and Objectives: The identification of possible biomarkers that can predict treatment response among DME eyes is important for the individualization of treatment plans. We investigated optical coherence tomography (OCT)-based biomarkers that may predict the one-year real-life outcomes among diabetic macular edema (DME) eyes following treatment by intravitreal ranibizumab (IVR) injections. Materials and Methods: A total of 65 eyes from 35 treatment-naïve patients with DME treated with ranibizumab injection were recruited. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), intraocular pressure (IOP), and OCT scans were retrospectively recorded at baseline before treatment and at 3 months, 6 months, and 12 months after treatment. The OCT scans were evaluated for biomarkers of interest, which included central retinal thickness (CRT), amount and locations of hyperreflective foci (HRF), subretinal fluid (SRF), intraretinal cysts (IRC), large outer nuclear layer cyst (LONLC), ellipsoid zone disruption (EZD), disorganization of retinal inner layers (DRIL), hard exudates (HE), epiretinal membrane (ERM), and vitreomacular interface (VMI). Correlations between these OCT biomarkers and outcome measures (visual and structural) were statistically analyzed. Results: A total of 65 eyes from 35 patients with DME were enrolled. The mean age was 64.2 ± 10.9 years old. Significant improvement in terms of mean BCVA (p < 0.005) and mean CRT was seen at final follow-up compared to baseline. The biomarkers of DRIL, LONLC, and SRF were found to be predictive for at least 50 µm CRT reduction after treatment (with odds ratio of 8.69, 8.5, and 17.58, respectively). The biomarkers of IRC, LONLC, and SRF were predictive for significant improvement in terms of BCVA and CRT after treatment. Finally, the number of HRF was predictive for both BCVA improvement and a CRT reduction of less than 100 µm after treatment. No serious complications were reported during the study. Conclusion: Our study demonstrated the utility of OCT biomarkers as therapeutic predictors of ranibizumab treatment among DME eyes.

Chronic exposure to low-level lipopolysaccharide dampens influenza-mediated inflammatory response via A20 and PPAR network.

Influenza A virus (IAV) infection leads to severe inflammation, and while epithelial-driven inflammatory responses occur via activation of NF-κB, the factors that modulate inflammation, particularly the negative regulators are less well-defined. In this study we show that A20 is a crucial molecular switch that dampens IAV-induced inflammatory responses. Chronic exposure to low-dose LPS environment can restrict this excessive inflammation. The mechanisms that this environment provides to suppress inflammation remain elusive. Here, our evidences show that chronic exposure to low-dose LPS suppressed IAV infection or LPS stimulation-induced inflammation in vitro and in vivo. Chronic low-dose LPS environment increases A20 expression, which in turn positively regulates PPAR-α and -γ, thus dampens the NF-κB signaling pathway and NLRP3 inflammasome activation. Knockout of A20 abolished the inhibitory effect on inflammation. Thus, A20 and its induced PPAR-α and -γ play a key role in suppressing excessive inflammatory responses in the chronic low-dose LPS environment.

Diabetic retinopathy as a potential risk factor for ptosis: A 13-year nationwide population-based cohort study in Taiwan.

Purpose: To determine the risk of ptosis among diabetic retinopathy (DR) patients. Methods: This is a population-based, retrospective, matched-cohort study where DR patients were recruited from the Taiwan National Health Insurance Research Database (NHIRD) to investigate the risk of developing ptosis. Preexisting co-factors of interest included smoking status and medical comorbidities of hyperlipidemia and hypertension. Statistical analysis was performed using T-test, Cox-proportional hazard ratios adjusted for comorbidities (aHR), Wilcoxon rank sum test, Kaplan-Meier estimators, and log rank tests. Results: Follow-up data of 9,494 patients with DR and 37,976 matched control cohort (non-DR) from 2000 to 2012 were analyzed. DR patients were found to have significantly increased risk of developing ptosis (adjusted hazard ratio (HR) [95% CI]: 2.76 [1.74-4.38], p < 0.001) when compared to the control cohort. From analysis in different strata, adult age and non-smokers were shown to have higher risk for ptosis development among DR patients. Furthermore, DR patients was also found to have increased risk of developing ptosis when compared to matched controls, regardless of whether they had medical comorbidities of lipid metabolism disorders or hypertension. Conclusions: In this large-scale study using real-world data, our results showed that DR patients were found to have increased risk of developing ptosis. Female gender, adult age, and non-smokers were also shown to increase the risk of ptosis among DR patients. This has implications towards the care of diabetic patients, complications such as ptosis should be properly screened for when encountering such patients. Before ptosis surgery, the possibility of underlying diabetes or DR should be also scrutinized and treated properly to avoid undesirable postoperative dissension.

Association between immune checkpoint inhibitor medication and uveitis: a population-based cohort study utilizing TriNetX database.

Objective: To explore the associations between the use of immune checkpoint inhibitors (ICIs) and the risk of developing uveitis among cancer patients. Methods: Cancer patients who received ICI therapy and a comparison group of cancer patients who did not receive ICI therapy were retrospectively recruited from the TriNetX electronic heath-record registry. The outcome of interest was the development of new-onset uveitis. Propensity score matching based on a 1:1 ratio was conducted in order to reduce bias. Multi-variate cox proportional hazard models and Kaplan Meier method were also utilized to assess for the risk of uveitis among cancer patients who received ICI therapy. Results: 71931 cancer patients (54.7% male; 76.5% white; mean age at index 63.6 ± 12.2 years) who received ICI treatment (ICI group) and 71931 cancer patients (54.7% male; 77% white; mean age at index 63.5 ± 12.4 years) who never received ICI (comparison group) were recruited. Associated Kaplan-Meier curves showed significantly increased uveitis risk among the ICI group for all follow-up years (p<0.001). The risk of uveitis was also higher among the ICI group during the 144-month follow-up period with a hazard ratio (HR) of 2.39 (95% CI: 2.07-2.75). Increased risk for specific uveitis diseases, such as iridocyclitis, chorioretinal inflammation, retinal vasculitis, unspecified purulent endophthalmitis, pan-uveitis and sympathetic uveitis were found. Subgroup analysis demonstrated an elevated hazard ratio for the development of uveitis among ICI recipients, spanning individuals below the age of 65 as well as those aged 65 and older. The elevated hazard ratio for uveitis development among ICI recipients was also observed across all genders, among those of white and Asian ethnicities, those with smoking history, and those with comorbid conditions such as hypertension and dyslipidemia, in comparison to their non-ICI counterparts. An additional subgroup analysis on monotherapy versus combinatory ICI regimens was also conducted. Individuals who received monotherapy from the class of anti-PD-1 (HR:1.98 [CI: 1.65-2.37]) and anti-CTLA-4 (HR:5.86 [CI:1.99-17.24]) exhibited elevated hazard ratios for uveitis development compared to their non-ICI comparators. Those exposed to combinatory ICI regimens, specifically a combination of anti-PD-1 and anti-CTLA4 (HR: 5.04 [CI:3.55-7.16]), showed increased hazard ratios for uveitis development compared to their non-ICI comparators. In contrast, individuals exposed to a combination of anti-PD-1 and anti-PD-L1 (HR: 2.47 [CI:0.81-7.50]) did not demonstrate an increased risk for uveitis compared to their non-ICI comparators. Conclusion: A significantly increased risk for uveitis diseases was found among the ICI group from the first year of follow-up. Increased awareness should be promoted on the occurrence of uveitis among cancer patients receiving ICI therapy.

Heterogeneity of neutrophils in cancer: one size does not fit all.

Neutrophils play an essential role in the defense against bacterial infections and orchestrate both the innate and adaptive immune responses. With their abundant numbers, diverse function and short life span, these cells are at the forefront of immune responses, and have gained attention in recent years because of their presence in tumor sites. Neutrophil involvement pertains to tumor cells' ability to construct a suitable tumor microenvironment (TME) that accelerates their own growth and malignancy, by facilitating their interaction with surrounding cells through the circulatory and lymphatic systems, thereby influencing tumor development and progression. Studies have indicated both pro- and anti-tumor properties of infiltrating neutrophils. The TME can exploit neutrophil function, recruitment, and even production, thus resulting in pro-tumor properties of neutrophils, including promotion of genetic instability, tumor cell proliferation, angiogenesis and suppression of anti-tumor or inflammatory response. In contrast, neutrophils can mediate anti-tumor resistance by direct cytotoxicity to the tumor cells or by facilitating anti-tumor functions via crosstalk with T cells. Here, we summarize current knowledge regarding the effects of neutrophil heterogeneity under homeostatic and tumor conditions, including neutrophil phenotype and function, in cancer biology.

Short-Term Effects of Brolucizumab in the Treatment of Wet Age-Related Macular Degeneration or Polypoidal Choroidopathy Refractory to Previous Anti-Vascular Endothelial Growth Factor Therapy.

Background and objectives: To report the initial response to a single intravitreal brolucizumab (IVI-B) injection in wet age-related macular degeneration (wAMD) or polypoidal choroidopathy (PCV) complicated with either persistent subretinal fluid (SRF) or pigment epithelial detachment refractory to previous anti-vascular endothelial growth factor (anti-VEGF) therapy. Material and methods: In this retrospective study, all eyes received a single IVI-B (6 mg/0.05 mL) for wAMD or PCV with treatment-resistant SRF or PED. Outcome measures included assessment in central retinal thickness (CRT), visual acuity, and evaluation for changes in the SRF or PED on OCT. Follow-up was prior to the first brolucizumab injection, then at 1 week and 5 weeks afterwards. Results: In total, 10 eyes of 10 patients (6 women [60%]) were enrolled. Five patients had wAMD and five patients had PCV. Average age of participants was 67.6 years. All patients received one IVI-B. All patients were not treatment-naïve to anti-VEGF agents. At the first week and fifth week following the first IVI-B, seven out of seven patients (100%) had resolved SRF. However, seven out of nine patients (78%) had no improvement of their PED at 5 weeks follow-up. Mean PED height and width before the first IVI-B was 339.77 µm and 2233.44 µm, respectively. Mean PED height and width at the fifthweek following the first IVI-B was 328.125 µm and 2129.5 µm, respectively. Overall mean visual acuity before the first IVI-B was 0.224; and 5 weeks following the first IVI-B was 0.38. Conclusions: Treatment with brolucizumab resulted in anatomical improvement for all patients with persistent SRF. Limited efficacy was seen for persistent PED. Brolucizumab appears to be a safe and effective option for treatment-resistant SRF. Future multicenter collaborative studies are warranted.

Sputum Metabolomic Profiling Reveals Metabolic Pathways and Signatures Associated With Inflammatory Phenotypes in Patients With Asthma.

PURPOSE: The molecular links between metabolism and inflammation that drive different inflammatory phenotypes in asthma are poorly understood. We aimed to identify the metabolic signatures and underlying molecular pathways of different inflammatory asthma phenotypes. METHODS: In the discovery set (n = 119), untargeted ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was applied to characterize the induced sputum metabolic profiles of asthmatic patients with different inflammatory phenotypes using orthogonal partial least-squares discriminant analysis (OPLS-DA), and pathway topology enrichment analysis. In the validation set (n = 114), differential metabolites were selected to perform targeted quantification. Correlations between targeted metabolites and clinical indices in asthmatic patients were analyzed. Logistic and negative binomial regression models were established to assess the association between metabolites and severe asthma exacerbations. RESULTS: Seventy-seven differential metabolites were identified in the discovery set. Pathway topology analysis uncovered that histidine metabolism, glycerophospholipid metabolism, nicotinate and nicotinamide metabolism, linoleic acid metabolism as well as phenylalanine, tyrosine and tryptophan biosynthesis were involved in the pathogenesis of different asthma phenotypes. In the validation set, 24 targeted quantification metabolites were significantly expressed between asthma inflammatory phenotypes. Finally, adenosine 5'-monophosphate (adjusted relative risk [adj RR] = 1.000; 95% confidence interval [CI] = 1.000-1.000; P = 0.050), allantoin (adj RR = 1.000; 95% CI = 1.000-1.000; P = 0.043) and nicotinamide (adj RR = 1.001; 95% CI = 1.000-1.002; P = 0.021) were demonstrated to predict severe asthma exacerbation rates. CONCLUSIONS: Different inflammatory asthma phenotypes have specific metabolic profiles in induced sputum. The potential metabolic signatures may identify therapeutic targets in different inflammatory asthma phenotypes.

Chemically-defined generation of human hemogenic endothelium and definitive hematopoietic progenitor cells.

Human hematopoietic stem cells (HSCs), which arise from aorta-gonad-mesonephros (AGM), are widely used to treat blood diseases and cancers. However, a technique for their robust generation in vitro is still missing. Here we show temporal manipulation of Wnt signaling is sufficient and essential to induce AGM-like hematopoiesis from human pluripotent stem cells. TGFß inhibition at the stage of aorta-like SOX17+CD235a- hemogenic endothelium yielded AGM-like hematopoietic progenitors, which closely resembled primary cord blood HSCs at the transcriptional level and contained diverse lineage-primed progenitor populations via single cell RNA-sequencing analysis. Notably, the resulting definitive cells presented lymphoid and myeloid potential in vitro; and could home to a definitive hematopoietic site in zebrafish and rescue bloodless zebrafish after transplantation. Engraftment and multilineage repopulating activities were also observed in mouse recipients. Together, our work provided a chemically-defined and feeder-free culture platform for scalable generation of AGM-like hematopoietic progenitor cells, leading to enhanced production of functional blood and immune cells for various therapeutic applications.

Enzyme-Responsive Peptide Thioesters for Targeting Golgi Apparatus.

The Golgi apparatus (GA) is the hub of intracellular trafficking, but selectively targeting GA remains a challenge. We show an unconventional types of peptide thioesters, consisting of an aminoethyl thioester and acting as substrates of thioesterases, for instantly targeting the GA of cells. The peptide thioesters, above or below their critical micelle concentrations, enter cells mainly via caveolin-mediated endocytosis or macropinocytosis, respectively. After being hydrolyzed by GA-associated thioesterases, the resulting thiopeptides form dimers and accumulate in the GA. After saturating the GA, the thiopeptides are enriched in the endoplasmic reticulum (ER). Their buildup in ER and GA disrupts protein trafficking, thus leading to cell death via multiple pathways. The peptide thioesters target the GA of a wide variety of cells, including human, murine, and Drosophila cells. Changing d-diphenylalanine to l-diphenylalanine in the peptide maintains the GA-targeting ability. In addition, targeting GA redirects protein (e.g., NRAS) distribution. This work illustrates a thioesterase-responsive and redox-active molecular platform for targeting the GA and controlling cell fates.

Endoplasmic reticulum-unfolded protein response signalling is altered in severe eosinophilic and neutrophilic asthma.

INTRODUCTION: The significance of endoplasmic reticulum (ER) stress in asthma is unclear. Here, we demonstrate that ER stress and the unfolded protein response (UPR) are related to disease severity and inflammatory phenotype. METHODS: Induced sputum (n=47), bronchial lavage (n=23) and endobronchial biopsies (n=40) were collected from participants with asthma with varying disease severity, inflammatory phenotypes and from healthy controls. Markers for ER stress and UPR were assessed. These markers were also assessed in established eosinophilic and neutrophilic murine models of asthma. RESULTS: Our results demonstrate increased ER stress and UPR pathways in asthma and these are related to clinical severity and inflammatory phenotypes. Genes associated with ER protein chaperone (BiP, CANX, CALR), ER-associated protein degradation (EDEM1, DERL1) and ER stress-induced apoptosis (DDIT3, PPP1R15A) were dysregulated in participants with asthma and are associated with impaired lung function (forced expiratory volume in 1 s) and active eosinophilic and neutrophilic inflammation. ER stress genes also displayed a significant correlation with classic Th2 (interleukin-4, IL-4/13) genes, Th17 (IL-17F/CXCL1) genes, proinflammatory (IL-1b, tumour necrosis factor α, IL-8) genes and inflammasome activation (NLRP3) in sputum from asthmatic participants. Mice with allergic airway disease (AAD) and severe steroid insensitive AAD also showed increased ER stress signalling in their lungs. CONCLUSION: Heightened ER stress is associated with severe eosinophilic and neutrophilic inflammation in asthma and may play a crucial role in the pathogenesis of asthma.