Hypoxia-inducible factor 1α activates the NLRP3 inflammasome to regulate epithelial differentiation in chronic rhinosinusitis

A long-term mixed eosinophilic and neutrophilic chronic rhinosinusitis C57BL/6 mouse model with neuroinflammation, olfactory dysfunction and anxiety-like behaviors

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by persistent inflammation and high recurrence rates. The mixed granulocytic endotype, marked by increased eosinophils and neutrophils, is particularly refractory and prone to relapse.

OBJECTIVE

This study aimed to evaluate the papain-induced mouse model for investigating the more refractory mixed granulocytic CRS endotype, characterized by elevated eosinophils and neutrophils.

METHODS

Male C57BL/6 mice were intranasally administered papain for 11 days to induce CRS. Cytokine profiles, nasal tissue histology, olfactory bulb analysis, assessments of olfactory function, cognition, anxiety-like and depression-like behaviors were performed at 30, 60, and 90 days post-treatment.

RESULTS

A long-term mixed eosinophilic and neutrophilic CRS model was successfully established, showing elevated IgE, IL-4, IL-5, IL-13, IL-33, TSLP, and TNF-α in nasal lavage fluid, alongside infiltration of eosinophils and neutrophils in both olfactory and respiratory regions. Chronic pathology included increased mast cells, goblet cells, basal cells, mucus hyperproduction, and epithelial damage, persisting up to 90 days, with partial improvement observed at the 60-day mark. Brain analysis revealed ongoing neuroinflammation, olfactory dysfunction, and anxiety-like behaviors in CRS mice, without signs of cognitive impairment or depression-like behaviors.

CONCLUSIONS

This study phenotypically delineated a long-term mixed eosinophilic and neutrophilic CRS mouse model, demonstrating sustained neuroinflammation, olfactory dysfunction, and anxiety-like behaviors following short-term papain exposure. These findings highlighted the role of mixed inflammation in CRS and provided a time-efficient platform for further exploration of its pathogenesis and mind-brain-body interactions.

In Obesity, Esophagogastric Junction Fat Impairs Esophageal Barrier Function and Dilates Intercellular Spaces via Hypoxia-Inducible Factor 2α

BACKGROUND & AIMS

Dilated intercellular space in esophageal epithelium, a sign of impaired barrier function, is a characteristic finding of gastroesophageal reflux disease that is also found in obese patients without gastroesophageal reflux disease. We explored molecular mechanisms whereby adipose tissue products might impair esophageal barrier integrity.

METHODS

Cultures of visceral fat obtained during foregut surgery from obese and nonobese patients were established. Monolayer and air-liquid interface cultures of human esophageal cells were grown with conditioned medium (CM) from fat cultures. RNA sequencing, enzyme-linked immunosorbent assay, western blot, immunostaining, histology, and analyses of barrier function were performed; inhibitors of hypoxia-inducible factor 2α (HIF-2α [PT2385]), caspase-1 (AC-YVAD-CHO), myosin light chain kinase (Dreverse PIK), and myosin light chain phosphatase (permeant inhibitor of phosphatase 250) were applied; blebbistatin was used to disrupt actin-myosin interactions; N-acetylcysteine was used to scavenge reactive oxygen species.

RESULTS

CM from esophagogastric junction fat of obese patients caused dilated intercellular space with impaired barrier function in esophageal air-liquid interface cultures; these effects were blocked by PT2385. CM from esophagogastric junction fat of obese patients induced reactive oxygen species production that activated HIF-2α in esophageal cells. RNA-sequencing analyses linked CM from esophagogastric junction fat of obese patient-induced HIF-2α increases with innate immune response pathways. Cross-talk between HIF-2α and caspase-1 in esophageal cells led to interleukin 1β secretion, and interleukin 1β/interleukin 1 receptor 1 signaling caused dilated intercellular space with impaired esophageal barrier function via actin-myosin interactions induced by myosin light chain phosphorylation.

CONCLUSIONS

We have elucidated molecular mechanisms whereby visceral fat of obese patients can impair esophageal barrier integrity by secreting substances that generate reactive oxygen species, which activate HIF-2α in esophageal epithelial cells. These mechanisms could render the esophagus of obese individuals vulnerable to damage from acid and other noxious agents.

Hypoxia-reduced YAP phosphorylation enhances expression of Mucin5AC in nasal epithelial cells of chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an upper respiratory disease characterized by persistent inflammation of the nasal mucosa. However, the mechanism of abnormal Mucin5AC expression by CRSwNP epithelial cells is not fully understood.

OBJECTIVE

We investigated the potential role of yes-associated protein (YAP) underlying the mechanism of excessive epithelial Mucin5AC expression in CRSwNP in a hypoxic model.

METHODS

Tissue biopsies of CRSwNP (n = 60), chronic rhinosinusitis without nasal polyps (CRSsNP) (n = 9) and healthy controls (n = 30) were investigated together with a well-established hypoxic model of primary human nasal epithelial cells (hNECs). The expression levels of hypoxia inducible factor (HIF)-1α and YAP, and the effect of the signaling axis on mucus secretion in hNECs were analyzed.

RESULTS

We observed a significant elevated expression levels of YAP in patients with CRSwNP and CRSsNP compared to controls. In addition, HIF-1α expression of CRSwNP was higher than that of control group. Under hypoxic conditions, HIF-1α was found to regulate the upregulation of YAP in hNECs. Further investigations revealed that HIF-1α facilitated the activation and nuclear localization of active-YAP by reducing the phosphorylation of YAP. This mechanism appeared to be linked to HIF-1α-mediated inhibition of LATS 1 phosphorylation and subsequent YAP degradation. HIF-1α was shown to promote the expression of P63 and the levels of Mucin5AC in hNECs by enhancing YAP activation.

CONCLUSION

Our findings indicated that hypoxia enhances YAP activation by decreasing p-LATS 1 and YAP phosphorylation. This has the potential to impact on the proliferation of basal cells and the differentiation of goblet cells in CRSwNP, ultimately leading to a pathological condition characterized by excessive Mucin5AC expression.

HIF-1α Enhances Intestinal Injury and Inflammation in Severe Acute Pancreatitis Through NLRP3 Inflammasome Activation

BACKGROUND

Severe Acute Pancreatitis (SAP) is associated with significant intestinal injury and inflammation. Hypoxia-Inducible Factor-1α (HIF-1α) and NLRP3 inflammasome have been implicated in this process, but their specific roles remain unclear.

OBJECTIVE

This study aims to elucidate the roles of HIF-1α and NLRP3 in the pathogenesis of SAP and their effects on intestinal injury, barrier function, and inflammatory responses.

METHODS

A SAP rat model was established, and histological changes were assessed via HE staining. Western blot was used to analyze HIF-1α and NLRP3 expression in intestinal mucosa. The effects of HIF-1α modulation were examined using the activator DMOG and inhibitor BAY87-2243. Immunohistochemistry, ELISA, and TUNEL staining were used to evaluate intestinal barrier function, permeability markers, and apoptosis.

RESULTS

HIF-1α and NLRP3 expression significantly increased in SAP rats, peaking at 72 h. HIF-1α activation aggravated intestinal injury and barrier dysfunction, decreasing tight junction protein levels and increasing epithelial apoptosis. Enhanced intestinal permeability and elevated pro-inflammatory cytokines were also observed. Furthermore, HIF-1α activation promoted NLRP3 inflammasome assembly, resulting in increased caspase-1 and IL-1β expression.

CONCLUSION

HIF-1α exacerbates intestinal injury and inflammation in SAP, likely through NLRP3 inflammasome activation. Targeting HIF-1α may offer a potential therapeutic approach for SAP-induced damage and inflammation.

Primary Cilia, Hypoxia, and Liver Dysfunction: A New Perspective on Biliary Atresia

Ciliopathies are disorders that affect primary or secondary cellular cilia or structures associated with ciliary function. Primary cilia (PC) are essential for metabolic regulation and embryonic development, and pathogenic variants in cilia-related genes are linked to several pediatric conditions, including renal-hepatic diseases and congenital defects. Biliary atresia (BA) is a progressive infantile cholangiopathy and the leading cause of pediatric liver transplantation. Although the exact etiology of BA remains unclear, evidence suggests a multifactorial pathogenesis influenced by both genetic and environmental factors. Patients with BA and laterality defects exhibit genetic variants associated with ciliopathies. Interestingly, even isolated BA without extrahepatic anomalies presents morphological and functional ciliary abnormalities, suggesting that environmental triggers may disrupt the ciliary function. Among these factors, hypoxia has emerged as a potential modulator of this dysfunction. Hypoxia-inducible factor 1-alpha (HIF-1α) plays a central role in hepatic responses to oxygen deprivation, influencing bile duct remodeling and fibrosis, which are key processes in BA progression. This review explores the crosstalk between hypoxia and hepatic ciliopathies, with a focus on BA. It discusses the molecular mechanisms through which hypoxia may drive disease progression and examines the therapeutic potential of targeting hypoxia-related pathways. Understanding how oxygen deprivation influences ciliary function may open new avenues for treating biliary ciliopathies and improving patient outcomes.

The Role of Yes-Associated Protein in Inflammatory Diseases and Cancer

Yes-associated protein (YAP) plays a central role in the Hippo pathway, primarily governing cell proliferation, differentiation, and apoptosis. Its significance extends to tumorigenesis and inflammatory conditions, impacting disease initiation and progression. Given the increasing relevance of YAP in inflammatory disorders and cancer, this study aims to elucidate its pathological regulatory functions in these contexts. Specifically, we aim to investigate the involvement and molecular mechanisms of YAP in various inflammatory diseases and cancers. We particularly focus on how YAP activation, whether through Hippo-dependent or independent pathways, triggers the release of inflammation and inflammatory mediators in respiratory, cardiovascular, and digestive inflammatory conditions. In cancer, YAP not only promotes tumor cell proliferation and differentiation but also modulates the tumor immune microenvironment, thereby fostering tumor metastasis and progression. Additionally, we provide an overview of current YAP-targeted therapies. By emphasizing YAP's role in inflammatory diseases and cancer, this study aims to enhance our understanding of the protein's pivotal involvement in disease processes, elucidate the intricate pathological mechanisms of related diseases, and contribute to future drug development strategies targeting YAP.

Supramolecular gel with enhanced immunomodulatory effects presents a minimally invasive treatment strategy for eosinophilic chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disease characterized by persistent immune dysregulation, which presents considerable limitations in current medical therapy.

OBJECTS

This study investigates a supramolecular gel (PSPD), which aims to minimize systemic adverse effects through local injection, provide long-lasting anti-inflammatory effects, and modulate the mucosal immune microenvironment.

METHODS

The properties of PSPD were evaluated using rheological experiments. Biocompatibility assessments were conducted through CCK-8 and serum biochemical analyses. The balance between TH17 and Treg was determined using immunofluorescence (IF) and flow cytometry (FC). Additionally, sinus computed tomography (CT), and endoscopy were employed to evaluate mucosal swelling.

RESULTS

Rheological assessments revealed that PSPD possesses excellent self-healing and slow-release properties. CCK-8 and serum biochemical assays indicated that PSPD demonstrated superior biocompatibility. In nasal polyps, PSPD significantly inhibited IL17 expression. In an Eosinophilic Chronic Rhinosinusitis (ECRS) rat model, treatment with PSPD led to significant alleviation of nasal mucosal congestion. Furthermore, PSPD modulated the proliferation of TH17 and Treg as well as the expression of cytokines, ultimately reversing the TH17/Treg immune imbalance.

CONCLUSION

This multifunctional gel effectively sustains the modulation of TH17/Treg homeostasis, improving long-term disease management and representing a promising new therapeutic strategy for CRS, particularly in cases of ECRS.

Establishment of nasal and olfactory epithelium organoids for unveiling mechanism of tissue regeneration and pathogenesis of nasal diseases

Organoid is an ideal in vitro model with cellular heterogeneity and genetic stability when passaging. Currently, organoids are exploited as new tools in a variety of preclinical researches and applications for disease modeling, drug screening, host-microbial interactions, and regenerative therapy. Advances have been made in the establishment of nasal and olfactory epithelium organoids that are used to investigate the pathogenesis of smell-related diseases and cellular/molecular mechanism underlying the regeneration of olfactory epithelium. A set of critical genes are identified to function in cell proliferation and neuronal differentiation in olfactory epithelium organoids. Besides, nasal epithelium organoids derived from chronic rhinosinusitis patients have been established to reveal the pathogenesis of this disease, potentially applied in drug responses in individual patient. The present article reviews recent research progresses of nasal and olfactory epithelium organoids in fundamental and preclinical researches, and proposes current advances and potential future direction in the field of organoid research and application.

Transcriptomic Analysis of Air-Liquid Interface Culture in Human Lung Organoids Reveals Regulators of Epithelial Differentiation

To develop in vitro respiratory models, it is crucial to identify the factors involved in epithelial cell differentiation. In this study, we comprehensively analyzed the effects of air-liquid interface (ALI) culture on epithelial cell differentiation using single-cell RNA sequencing (scRNA-seq). ALI culture induced a pronounced shift in cell composition, marked by a fivefold increase in ciliated cells and a reduction of more than half in basal cells. Transcriptional signatures associated with epithelial cell differentiation, analyzed using iPathwayGuide software, revealed the downregulation of VEGFA and upregulation of CDKN1A as key signals for epithelial differentiation. Our findings highlight the efficacy of the ALI culture for replicating the human lung airway epithelium and provide valuable insights into the crucial factors that influence human ciliated cell differentiation.

Danshen injection mitigated the cerebral ischemia/reperfusion injury by suppressing neuroinflammation via the HIF-1α/CXCR4/NF-κB signaling pathway

Danshen injection (DI) is effective in treating cardiovascular and cerebrovascular diseases, including ischemic stroke (IS), including IS, but its mechanism is unclear. A middle cerebral artery occlusion model was used to simulate ischemia/reperfusion (I/R) injury in SD rats. Overexpression of hypoxia-inducible factor 1α (HIF-1α) was achieved by AAV-HIF-1α. Rats were treated with DI or saline. Neurological scores and infarction rates were assessed. I/R damage was examined by HE, 2,3,5-triphenyltetrazolium and Nissl stainings. Expression levels of relative proteins [TNF-α, IL-6, IL-1β, SOD, MDA, ROS, HIF-1α, CXC chemokine receptor 4 (CXCR4) and NF-κB] were measured. DI treatment improved neurological scores and reduced infarction rates, suggesting that it inhibits inflammation and oxidative stress. The expression levels of HIF-1α, CXCR4 and NF-κB were decreased. However, the effectiveness of DI on inflammation inhibition was lost after HIF-1α overexpression. DI may directly target HIF-1α to suppress neuroinflammation and reduce I/R injury by suppressing the HIF-1α/CXCR4/NF-κB signaling pathway.

Exacerbated Activation of the NLRP3 Inflammasome in the Placentas from Women Who Developed Chronic Venous Disease during Pregnancy

Chronic venous disease (CVD) comprises a spectrum of morphofunctional disorders affecting the venous system, affecting approximately 1 in 3 women during gestation. Emerging evidence highlights diverse maternofetal implications stemming from CVD, particularly impacting the placenta. While systemic inflammation has been associated with pregnancy-related CVD, preliminary findings suggest a potential link between this condition and exacerbated inflammation in the placental tissue. Inflammasomes are major orchestrators of immune responses and inflammation in different organs and systems. Notwithstanding the relevance of inflammasomes, specifically the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3)- which has been demonstrated in the placentas of women with different obstetric complications, the precise involvement of this component in the placentas of women with CVD remains to be explored. This study employs immunohistochemistry and real-time PCR (RT-qPCR) to examine the gene and protein expression of key components in both canonical and non-canonical pathways of the NLRP3 inflammasome (NLRP3, ASC-apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain-caspase 1, caspase 5, caspase 8, and interleukin 1β) within the placental tissue of women affected by CVD. Our findings reveal a substantial upregulation of these components in CVD-affected placentas, indicating a potential pathophysiological role of the NLRP3 inflammasome in the development of this condition. Subsequent investigations should focus on assessing translational interventions addressing this dysregulation in affected patient populations.

MicroRNA-145-5p Regulates the Epithelial-Mesenchymal Transition in Nasal Polyps by Targeting Smad3

OBJECTIVES

The annual prevalence of chronic rhinosinusitis (CRS) is increasing, and the lack of effective treatments imposes a substantial burden on both patients and society. The formation of nasal polyps in patients with CRS is closely related to tissue remodeling, which is largely driven by the epithelial-mesenchymal transition (EMT). MicroRNA (miRNA) plays a pivotal role in the pathogenesis of numerous diseases through the miRNA-mRNA regulatory network; however, the specific mechanism of the miRNAs involved in the formation of nasal polyps remains unclear.

METHODS

The expression of EMT markers and Smad3 were detected using western blots, quantitative real-time polymerase chain reaction, and immunohistochemical and immunofluorescence staining. Differentially expressed genes in nasal polyps and normal tissues were screened through the Gene Expression Omnibus database. To predict the target genes of miR-145-5p, three different miRNA target prediction databases were used. The migratory ability of cells was evaluated using cell migration assay and wound healing assays.

RESULTS

miR-145-5p was associated with the EMT process and was significantly downregulated in nasal polyp tissues. In vitro experiments revealed that the downregulation of miR-145-5p promoted EMT. Conversely, increasing miR-145-5p levels reversed the EMT induced by transforming growth factor-β1. Bioinformatics analysis suggested that miR-145-5p targets Smad3. Subsequent experiments confirmed that miR-145-5p inhibits Smad3 expression.

CONCLUSION

Overall, miR-145-5p is a promising target to inhibit nasal polyp formation, and the findings of this study provide a theoretical basis for nanoparticle-mediated miR-145-5p delivery for the treatment of nasal polyps.

Heat shock protein 90 and prolyl hydroxylase 2 co-regulate hypoxia-inducible factor-1α expression in porcine small intestinal epithelial cells under heat stress

Heat stress (HS) poses a substantial threat to animal growth and development, resulting in declining performance and economic losses. The intestinal system is susceptible to HS and undergoes intestinal hyperthermia and pathological hypoxia. Hypoxia-inducible factor-1α (HIF-1α), a key player in cellular hypoxic adaptation, is influenced by prolyl-4-hydroxylase 2 (PHD2) and heat shock protein 90 (HSP90). However, the comprehensive regulation of HIF-1α in the HS intestine remains unclear. This study aims to explore the impact of HS on pig intestinal mucosa and the regulatory mechanism of HIF-1α. Twenty-four Congjiang Xiang pigs were divided into the control and five HS-treated groups (6, 12, 24, 48, and 72 h). Ambient temperature and humidity were maintained in a thermally-neutral state (temperature-humidity index (THI) < 74) in the control group, whereas the HS group experienced moderate HS (78 < THI <84). Histological examination revealed villus exfoliation after 12 h of HS in the duodenum, jejunum, and ileum, with increasing damage as HS duration extended. The villus height to crypt depth ratio (V/C) decreased and goblet cell number increased with prolonged HS. Quantitative real-time PCR, Western blot, and immunohistochemistry analysis indicated increased expression of HIF-1α and HSP90 in the small intestine with prolonged HS, whereas PHD2 expression decreased. Further investigation in IPEC-J2 cells subjected to HS revealed that overexpressing PHD2 increased PHD2 mRNA and protein expression, while it decreases HIF-1α. Conversely, interfering with HSP90 expression substantially decreased both HSP90 and HIF-1α mRNA and protein levels. These results suggest that HS induces intestinal hypoxia with concomitant small intestinal mucosal damage. The expression of HIF-1α in HS-treated intestinal epithelial cells may be co-regulated by HSP90 and PHD2 and is possibly linked to intestinal hyperthermia and hypoxia.