Expression of leptin receptor in nasal polyps: leptin as a mucosecretagogue

Evaluating the Association of Obesity and Chronic Rhinosinusitis: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of this Meta-analysis and systematic review was to perform a comprehensive assessment of the association of chronic rhinosinusitis (CRS) with overweight/obesity, leptin hormone, and its associated metabolic dysregulation.

DATA SOURCES

Ovid MEDLINE, Embase, Web of Science, and Cochrane Central Register of Controlled Trials, were searched for studies from 1946 to October 2022, using predefined syntax.

REVIEW METHODS

Outcome data for the meta-analysis were extracted on odds ratios (OR) of CRS prevalence based on the presence of overweight/obesity and mean serum leptin levels. A Meta-analysis was performed using the DerSimonian-Laird estimator to pool extracted data by the generalized inverse variance approach. Random effect models were utilized due to the small sample size. A qualitative synthesis was performed on articles that did not meet the inclusion criteria for the Meta-analysis.

RESULTS

Thirty-six studies met the systematic review inclusion criteria out of 1113 articles screened. A total of 6 studies were included in the pooled Meta-analysis of the various outcome variables. Our pooled meta-analysis observed a positive association between overweight/obesity and the prevalence of CRS (OR = 1.33, 95% confidence interval [CI]: 1.17-1.51). The pooled ratio of the means analysis of the mean serum leptin levels between CRS with nasal polyposis and control patients was 2.21 (95% CI: 1.45; 3.36).

CONCLUSION

Our pooled Meta-analysis indicates a positive association between overweight/obesity and CRS. Future prospective studies are needed to explore the association between CRS and obesity with an understanding of potential confounding comorbidities, including studies focused on assessing the underlying immunologic mechanism of this association.

Nose-to-brain delivery of nanotherapeutics: Transport mechanisms and applications

The blood-brain barrier presents a key limitation to the administration of therapeutic molecules for the treatment of brain disease. While drugs administered orally or intravenously must cross this barrier to reach brain targets, the unique anatomical structure of the olfactory system provides a route to deliver drugs directly to the brain. Entering the brain via receptor, carrier, and adsorption-mediated transcytosis in the nasal olfactory and trigeminal regions has the potential to increase drug delivery. In this review, we introduce the physiological and anatomical structures of the nasal cavity, and summarize the possible modes of transport and the relevant receptors and carriers in the nose-to-brain pathway. Additionally, we provide examples of nanotherapeutics developed for intranasal drug delivery to the brain. Further development of nanoparticles that can be applied to intranasal delivery systems promises to improve drug efficacy and reduce drug resistance and adverse effects by increasing molecular access to the brain. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease.

Ghrelin Downregulates Lipopolysaccharide/ Leptin-Induced MUC5AC Expression in Human Nasal Epithelial Cells

OBJECTIVES

Obesity, which induces chronic low-grade systemic inflammation in the human body, is a known risk factor for various diseases. Recent studies have shown associations between various otorhinolaryngological diseases and obesity. In particular, inflammatory sinonasal diseases have been found to be strongly associated with obesity-related proinflammatory mediators. Many studies have been conducted to identify therapeutic agents for controlling obesity-related inflammatory airway diseases. Ghrelin, an endogenous peptide from the stomach, has anti-inflammatory and antioxidative effects in a wide range of tissues. However, the effect of ghrelin on the regulation of mucus secretion has not yet been studied in the human nasal mucosa. Therefore, we investigated the effects of ghrelin on lipopolysaccharide (LPS)/leptin-mediated MUC5AC expression and mechanisms involved in human nasal epithelial cells (HNEpCs).

METHODS

In HNEpCs, the effect and signaling pathways of ghrelin on LPS/leptin-induced MUC5AC expression were examined using reverse transcription polymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassays, Western blotting, and immunofluorescence staining.

RESULTS

Growth hormone secretagogue receptor 1a (GHSR1a) was expressed in the HNEpCs. Ghrelin downregulated LPS/leptin-induced MUC5AC expression, which was abolished by D-Lys-3-growth hormone-releasing peptide 6 (D-Lys-3-GHRP-6). Ghrelin significantly inhibited LPS/leptin-activated extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinases (MAPKs). These ghrelin-mediated changes in MAPK activation were abolished by D-Lys-3-GHRP-6. These.

RESULTS

showed that ghrelin inhibits LPS/leptin-induced MUC5AC overexpression by modulating the ERK1/2 and p38 MAPK pathways in HNEpCs.

CONCLUSION

These findings suggest that ghrelin is a potential therapeutic agent for treating obesity-related inflammatory sinonasal diseases.

Benzisothiazolinone upregulates the MUC5AC expression via ERK1/2, p38, and NF-κB pathways in airway epithelial cells

Mucus plays an important role in protecting the respiratory tract from irritants. However, mucus hypersecretion is a major indicator of airway diseases. 1,2-Benzisothiazolin-3-one (BIT), as a microbicide, induces asthmatic inflammation. Therefore, we focused on the effects of BIT-related mucin secretion in airway epithelial cells. Our in vivo study showed increased mucus and MUC5AC expressions in the bronchioles of mice that inhaled BIT. For investigating the signaling pathways, we performed experiments in human airway epithelial cells. BIT induced the MUC5AC expression and significantly increased the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The specific inhibitors of ERK1/2, p38, and NF-κB blocked the BIT-induced MUC5AC expression. Therefore, these results suggest that BIT induces the MUC5AC expression via the ERK1/2, p38, and NF-κB pathways in human airway epithelial cells, which may be involved in mucus hypersecretion associated with airway inflammatory diseases.

Endoplasmic Reticulum Stress Induces MUC5AC and MUC5B Expression in Human Nasal Airway Epithelial Cells

Objectives

Endoplasmic reticulum (ER) stress is known to be associated with inflammatory airway diseases, and three major transmembrane receptors: double-stranded RNA-activated protein kinase-like ER kinase, inositol requiring enzyme 1, and activating transcription factor 6 (ATF6) play important roles in ER stress-related proinflammatory signaling. However, the effects of ER stress and these three major signaling pathways on the regulation of the production of airway mucins in human nasal airway epithelial cells have not been elucidated.

Methods

In primary human nasal epithelial cells, the effect of tunicamycin (an ER stress inducer) and 4-phenylbutyric acid (4-PBA, ER stress inhibitor) on the expression of MUC5AC and MUC5B was investigated by reverse transcriptasepolymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and immunoblot analysis. Small interfering RNA (siRNA) transfection was used to identify the mechanisms involved.

Results

Tunicamycin increased the expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules, including spliced X-box binding protein 1 (XBP-1), transcription factor CCAAT-enhancer-binding protein homologous protein (CHOP), and ATF6. In addition, 4-PBA attenuated the tunicamycin-induced expressions of MUC5AC and MUC5B and the mRNA expressions of ER stress-related signaling molecules. Furthermore, siRNA knockdowns of XBP-1, CHOP, and ATF6 blocked the tunicamycin-induced mRNA expressions and glycoprotein productions of MUC5AC and MUC5B.

Conclusion.

These results demonstrate that ER stress plays an important role in the regulation of MUC5AC and MUC5B via the activations of XBP-1, CHOP, and ATF6 in human nasal airway epithelial cells.

Clusterin Induces MUC5AC Expression via Activation of NF-κB in Human Airway Epithelial Cells

Objectives

Clusterin (CLU) is known as apolipoprotein J, and has three isoforms with different biological functions. CLU is associated with various diseases such as Alzheimer disease, atherosclerosis, and some malignancies. Recent studies report an association of CLU with inflammation and immune response in inflammatory airway diseases. However, the effect of CLU on mucin secretion of airway epithelial cells has not yet been understood. Therefore, the effect and brief signaling pathway of CLU on MUC5AC (as a major secreted mucin) expression were investigated in human airway epithelial cells.

Methods

In the tissues of nasal polyp and normal inferior turbinate, the presence of MUC5AC and CLU was investigated using immunohistochemical stain and Western blot analysis. In mucin-producing human NCI-H292 airway epithelial cells and primary cultures of normal nasal epithelial cells, the effect and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway of CLU on MUC5AC expression were investigated using immunohistochemical stain, reverse transcription-polymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and Western blot analysis.

Results

In the nasal polyps, MUC5AC and CLU were abundantly present in the epithelium on immunohistochemical stain, and nuclear CLU (nCLU) was strongly detected on Western blot analysis. In human NCI-H292 airway epithelial cells or the primary cultures of normal nasal epithelial cells, recombinant nCLU increased MUC5AC expression, and significantly activated phosphorylation of NF-κB. And BAY 11-7085 (a specific NF-κB inhibitor) and knockdown of NF-κB by NF-κB siRNA (small interfering RNA) significantly attenuated recombinant nCLU-induced MUC5AC expression.

Conclusion

These results suggest that nCLU induces MUC5AC expression via the activation of NF-κB signaling pathway in human airway epithelial cells.

Intranasal delivery of N-terminal modified leptin-pluronic conjugate for treatment of obesity

Leptin is an adipocyte-secreted hormone that is delivered via a specific transport system across the blood-brain barrier (BBB) to the brain where it acts on the hypothalamus receptors to control appetite and thermogenesis. Peripheral resistance to leptin due to its impaired brain delivery prevents therapeutic use of leptin in overweight and moderately obese patients. To address this problem, we modified the N-terminal amine of leptin with Pluronic P85 (LepNP85) and administered this conjugate intranasally using the nose-to-brain (INB) route to bypass the BBB. We compared this conjugate with the native leptin, the N-terminal leptin conjugate with poly(ethylene glycol) (LepNPEG5K), and two conjugates of leptin with Pluronic P85 attached randomly to the lysine amino groups of the hormone. Compared to the random conjugates of leptin with P85, LepNP85 has shown higher affinity upon binding with the leptin receptor, and similarly to native hormone activated hypothalamus receptors after direct injection into brain. After INB delivery, LepNP85 conjugate was transported to the brain and accumulated in the hypothalamus and hippocampus to a greater extent than the native leptin and LepNPEG5K and activated leptin receptors in hypothalamus at lower dose than native leptin. Our work suggests that LepNP85 can access the brain directly after INB delivery and confirms our hypothesis that the improvement in brain accumulation of this conjugate is due to its enhanced brain absorption. In conclusion, the LepNP85 with optimized conjugation chemistry is a promising candidate for treatment of obesity.

Host genetic variation impacts microbiome composition across human body sites

BACKGROUND

The composition of bacteria in and on the human body varies widely across human individuals, and has been associated with multiple health conditions. While microbial communities are influenced by environmental factors, some degree of genetic influence of the host on the microbiome is also expected. This study is part of an expanding effort to comprehensively profile the interactions between human genetic variation and the composition of this microbial ecosystem on a genome- and microbiome-wide scale.

RESULTS

Here, we jointly analyze the composition of the human microbiome and host genetic variation. By mining the shotgun metagenomic data from the Human Microbiome Project for host DNA reads, we gathered information on host genetic variation for 93 individuals for whom bacterial abundance data are also available. Using this dataset, we identify significant associations between host genetic variation and microbiome composition in 10 of the 15 body sites tested. These associations are driven by host genetic variation in immunity-related pathways, and are especially enriched in host genes that have been previously associated with microbiome-related complex diseases, such as inflammatory bowel disease and obesity-related disorders. Lastly, we show that host genomic regions associated with the microbiome have high levels of genetic differentiation among human populations, possibly indicating host genomic adaptation to environment-specific microbiomes.

CONCLUSIONS

Our results highlight the role of host genetic variation in shaping the composition of the human microbiome, and provide a starting point toward understanding the complex interaction between human genetics and the microbiome in the context of human evolution and disease.