IL-10/HMOX1 signaling modulates cochlear inflammation via negative regulation of MCP-1/CCL2 expression in cochlear fibrocytes

Recent progress on anti-nociceptive effects of carbon monoxide releasing molecule-2 (CORM-2)

The role of carbon monoxide (CO) has evolved albeit controversial disputes on its toxicity. This biological gasotransmitter participates in the endogenous regulation of neurotransmitters and neuropeptides released in the nervous system. Exogenous CO gas inhalation at a lower concentration has been the subject of investigations, which have revealed its biological homeostatic mechanisms and protective effects against many pathological conditions. This therapeutic procedure of CO is, however, limited due to its immediate release, which favours haemoglobin at a high affinity with the subsequent generation of toxic carboxyhaemoglobin in tissues. In order to address this problem, carbon monoxide releasing molecule-2 (CORM-2) or also known as tricarbonyldichlororuthenium II dimer is developed to liberate a controlled amount of CO in the biological systems. In this review, we examine several potential mechanisms exerted by this therapeutic compound to produce the anti-nociceptive effect that has been demonstrated in previous studies. This review could shed light on the role of CORM-2 to reduce pain, especially in cases of chronic and neuropathic pain.

Analysis of Serum Inflammatory Markers in Infants Under 6 Months of Age with Non-Syndromic Moderate and Severe Hearing Loss Associated with GJB2 Gene Mutations

BACKGROUND The GJB2 gene is reported to be the main hereditary factor responsible for non-syndromic hearing impairment in infants. Several kinds of hearing loss have been linked to elevated inflammatory markers. This study aimed to evaluate serum levels of IL-2, IL-4, IL-6, IL-10, IL-17, alpha-TNF, and γ-IFN and the severity of hearing loss. MATERIAL AND METHODS Ninety newborns were divided into 3 groups: severe hearing impairment (31 infants), moderate hearing impairment (30 infants), and normal hearing (29 infants). Hearing screening was performed using otoacoustic emissions test. Mutations of the GJB2 gene were detected with Sanger sequencing. The patients had DNFB1 mutation. Seven blood inflammatory markers were tested using Cytometric Bead Array. We performed the t test to examine differences in expression of 7 inflammatory markers between sexes in the groups. The correlation between indicators within groups was studied using the Pearson correlation test. Correlation of different indicators among groups was studied using the Spearman correlation test. RESULTS When compared among the 3 groups (severe, moderate hearing impairment, and normal hearing group), we found that IL-10 had a positive correlation with the severity of GJB2-associated hearing loss, which was statistically significant (P<0.05). CONCLUSIONS This research aimed to assess the relationship of 7 serum inflammatory markers with GJB2-associated hearing loss in infants. Inflammatory marker IL-10 had a positive correlation with the severity of GJB2-associated infant hearing loss, and it might have the potential to become a future therapeutic target.

T-cell dysfunction in the glioblastoma microenvironment is mediated by myeloid cells releasing interleukin-10

Despite recent advances in cancer immunotherapy, certain tumor types, such as Glioblastomas, are highly resistant due to their tumor microenvironment disabling the anti-tumor immune response. Here we show, by applying an in-silico multidimensional model integrating spatially resolved and single-cell gene expression data of 45,615 immune cells from 12 tumor samples, that a subset of Interleukin-10-releasing HMOX1+ myeloid cells, spatially localizing to mesenchymal-like tumor regions, drive T-cell exhaustion and thus contribute to the immunosuppressive tumor microenvironment. These findings are validated using a human ex-vivo neocortical glioblastoma model inoculated with patient derived peripheral T-cells to simulate the immune compartment. This model recapitulates the dysfunctional transformation of tumor infiltrating T-cells. Inhibition of the JAK/STAT pathway rescues T-cell functionality both in our model and in-vivo, providing further evidence of IL-10 release being an important driving force of tumor immune escape. Our results thus show that integrative modelling of single cell and spatial transcriptomics data is a valuable tool to interrogate the tumor immune microenvironment and might contribute to the development of successful immunotherapies.

Mild Therapeutic Hypothermia and Putative Mechanisms of Hair Cell Survival in the Cochlea

Significance: Sensorineural hearing loss has significant implications for quality of life and risk for comorbidities such as cognitive decline. Noise and ototoxic drugs represent two common risk factors for acquired hearing loss that are potentially preventable. Recent Advances: Numerous otoprotection strategies have been postulated over the past four decades with primary targets of upstream redox pathways. More recently, the application of mild therapeutic hypothermia (TH) has shown promise for otoprotection for multiple forms of acquired hearing loss. Critical Issues: Systemic antioxidant therapy may have limited application for certain ototoxic drugs with a therapeutic effect on redox pathways and diminished efficacy of the primary drug's therapeutic function (e.g., cisplatin for tumors). Future Directions: Mild TH likely targets multiple mechanisms, contributing to otoprotection, including slowed metabolics, reduced oxidative stress, and involvement of cold shock proteins. Further work is needed to identify the mechanisms of mild TH at play for various forms of acquired hearing loss.

Identifying the effectual-combination ingredients of Zhi-zi-Hou-po decoction based on metabolic difference-oriented network regulation strategy

Zhi-zi-Hou-po decoction (ZZHPD) has been used to treat depression in the clinic for thousand years in China. However, the pharmacodynamic substance of ZZHPD is still not totally clear due to its complex components. The objective of this study was to identify the effectual combination ingredients (ECIs) of ZZHPD, which could represent the antidepressant effect of the original formula. Firstly, differential plasma absorbed components with different variable importance in projection (VIP) value in chronic unpredictable mild stress (CUMS)-induced depression and control rat were revealed by untargeted metabolomics-driven strategy based on HPLC-ESI-TOF/MS, XCMS online and SIMCA-p software. Secondly, network topology scores (NTS) of plasma absorbed components were exposed by protein-protein interaction (PPI) network analysis based on components-related genes and depression-related genes, which were performed by network pharmacology tools. Finally, the ECIs were screened by considered of VIP value and NTS. Then the bioactivity was evaluated by cell viability and expression of glial fibrillary acid protein (GFAP), tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β) of a lipopolysaccharide-induced astrocyte depression model. An effective combination composed with 12 components was filtrated as ECIs of ZZHPD, exposed to which the cell viability effect, the expression of GFAP and IL-1β in astrocytes were essentially equivalent with original ZZHPD (p > 0.05), and that both characteristic constituents and trace compounds of ZZHPD might exert synergistic actions through multi-targets. The result of this study provided useful information for the clinical application and modern development of ZZHPD, and the proposed strategy could be regard as an alternative solution for effective combination screening of herbal medicines.

Prior transfusion of umbilical cord mesenchymal stem cells can effectively alleviate symptoms of motion sickness in mice through interleukin 10 secretion

BACKGROUND

Motion sickness (MS) is a disease that occurs during unbalanced movement, characterized by gastrointestinal symptoms and autonomic nervous system activation. Current clinical treatments for MS are limited. Recent evidence indicates that the levels of pro-inflammatory cytokines increase during MS and are associated with an inner ear immune imbalance. In the present study, mesenchymal stem cells (MSCs) have been shown to exert strong immuno-suppressive effects.

AIM

To explore whether umbilical cord-derived mesenchymal stem cells (UC-MSCs) can prevent the occurrence of MS, and the underlying mechanism regulated by MSCs in a mouse model of MS.

METHODS

A total of 144 (equal numbers of males and females) 5wkold BALB/c mice were randomly divided into five groups: Normal group (n = 16), MS group (n = 32), MSCs group (n = 32), MS + MSCs group (n = 32), and MS + AS101/MSCs group (n = 32). The MSCs group (n = 32), MS + MSCs group (n = 32), and MS + AS101/MSCs group (n = 32) were preventively transplanted with UC-MSCs or AS101-treated UC-MSCs (1 × 10⁶ cells/mouse). Mice in the MS (n = 32), MS + MSCs, and MS + AS101/MSCs groups were subjected to rotation on a centrifuge for 10 min at 8 × g/min for MS model establishment on days 3, 5, 8, and 10 after UC-MSCs injection. The Morris water maze (MWM) test was used to observe the symptom of dizziness. Enzyme-linked immunosorbent assay (ELISA) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to detect the levels of inflammatory cytokines in mice peripheral blood and the petrous part of the temporal bone samples. Western blot analysis was performed to analyze the JAK2/STAT3 signaling pathway in the cochlear tissues. Histological examination was performed by hematoxylin and eosin (HE) staining for conventional morphological evaluation in the petrous part of temporal bone samples.

RESULTS

The MWM test demonstrated that UC-MSCs improved the symptoms of MS. The MS + MSCs group was faster than the MS group on days 3 and 5 (P = 0.036 and P = 0.002, respectively). ELISA and RT-qPCR showed that the serum and mRNA levels of interleukin-10 (IL-10) in the cochlear tissues were increased after transplantation with UC-MSCs (MS + MSCs group vs MS group at 3 and 5 d, P = 0.002 and ^cP < 0.001, respectively). RT-qPCR results confirmed a significant increase in IL-10 levels at four time points (MS + MSCs group vs MS group, P = 0.009, P = 0.009, P = 0.048, and P = 0.049, respectively). This suggested that UC-MSCs reduced the sensitivity of the vestibular microenvironment by secreting IL-10. Moreover, Western blot analysis showed that the MSCs activated the JAK2/STAT3 signaling pathway in the cochlear tissues. The levels of IL-10, IL-10RA, JAK2, STAT3, and phosphorylated JAK2 and STAT3 in the MS + MSCs group were increased compared to those of the MS group (P < 0.05). The morphological changes in the four groups showed no significant differences. The role of IL-10 secretion on the ability of UC-MSCs to successfully improve the symptoms of MS was confirmed by the diminished therapeutic effects associated with treatment with the IL-10 inhibitor ammonium trichloro (dioxoethylene-o,o′) tellurate (AS101).

CONCLUSION

Prophylactic transplantation of UC-MSCs can alleviate the clinical symptoms of MS in mice, particularly at 3-5 d after preventive transplantation. The mechanism for UC-MSCs to reduce the sensitivity of vestibular cortex imbalance may be the secretion of IL-10. The next step is to demonstrate the possibility of curing MS in the vestibular environment by intermittent transplantation of MSCs. Above all, MSCs are expected to become a new method for the clinical prevention and treatment of MS.

Serum Bilirubin Level as a Potential Marker for the Hearing Outcome in Severe-Profound Bilateral Sudden Deafness

Supplemental Digital Content is available in the text

Objective:

To investigate the association of serum bilirubin level with hearing outcomes in bilateral sudden sensorineural hearing loss (BSSHL) patients.

Participants:

One hundred thirteen in-patient BSSHL patients were consecutively enrolled between July 2008 and December 2015 in a tertiary center.

Main Outcome Measures:

Multivariable linear regression, generalized estimating equations (GEE), and stratified analyses were applied to examine the association between serum bilirubin level and hearing outcome measures such as final hearing threshold and absolute and relative hearing gains in BSSHL.

Results:

After full adjustment for potential confounders, total bilirubin levels (TBIL) were observed to be positively and independently associated with hearing outcomes as measured by final hearing (β [95% confidence interval {CI}]: −1.5 [−2.7, −0.2] dB HL per 1 μmol/L increase in TBIL) and absolute and relative hearing gains (β [95% CI]: 1.4 [0.2, 2.7] dB and 1.6 [0.2, 3.1] dB, respectively) in the severe to profound hearing loss subpopulation.

Conclusions:

Higher TBIL levels, within the normal or mildly elevated ranges, were independently and significantly associated with better hearing outcome in BSSHL patients with severe to profound hearing loss. Given bilirubin elevation treatments exist, our finding suggests a novel pharmacological strategy for this specific subpopulation.

Lactobacillus paracasei PS23 decelerated age-related muscle loss by ensuring mitochondrial function in SAMP8 mice

Sarcopenia is a common impairment in the elderly population responsible for poor outcomes later in life; it can be caused by age-related alternations. Only a few strategies have been reported to reduce sarcopenia. Lactobacillus paracasei PS23 (LPPS23) has been reported to delay some age-related disorders. Therefore, here we investigated whether LPPS23 decelerates age-related muscle loss and its underlying mechanism. Female senescence-accelerated mouse prone-8 (SAMP8) mice were divided into three groups (n=6 each): non-aging (16-week-old), control (28-week-old), and PS23 (28-week-old) groups. The control and PS23 groups were given saline and LPPS23, respectively. We evaluated the effects of LPPS23 by analyzing body weight and composition, muscle strength, protein uptake, mitochondrial function, reactive oxygen species (ROS), antioxidant enzymes, and inflammation-related cytokines. LPPS23 significantly attenuated age-related decreases of muscle mass and strength. Compared to the control group, the non-aging and PS23 groups exhibited higher mitochondrial function, IL10, antioxidant enzymes, and protein uptake. Moreover, inflammatory cytokines and ROS were lower in the non-aging and PS23 groups than the control group. Taken together, LPPS23 extenuated sarcopenia progression during aging; this effect might have been enacted by preserving the mitochondrial function via reducing age-related inflammation and ROS and by retaining protein uptake in the SAMP8 mice.

Current Understanding of Host Genetics of Otitis Media

The pathogenesis of otitis media (OM), an inflammatory disease of the middle ear (ME), involves interplay between many different factors, including the pathogenicity of infectious pathogens, host immunological status, environmental factors, and genetic predisposition, which is known to be a key determinant of OM susceptibility. Animal models and human genetics studies have identified many genes and gene variants associated with OM susceptibility: genes that encode components of multiple signaling pathways involved in host immunity and inflammatory responses of the ME mucosa; genes involved in cellular function, such as mucociliary transport, mucin production, and mucous cell metaplasia; and genes that are essential for Eustachian tube (ET) development, ME cavitation, and homeostasis. Since our last review, several new mouse models with mutations in genes such as CCL3, IL-17A, and Nisch have been reported. Moreover, genetic variants and polymorphisms in several genes, including FNDC1, FUT2, A2ML1, TGIF1, CD44, and IL1-RA variable number tandem repeat (VNTR) allele 2, have been identified as being significantly associated with OM. In this review, we focus on the current understanding of the role of host genetics in OM, including recent discoveries and future research prospects. Further studies on the genes identified thus far and the discovery of new genes using advanced technologies such as gene editing, next generation sequencing, and genome-wide association studies, will advance our understanding of the molecular mechanism underlying the pathogenesis of OM and provide new avenues for early screening and developing effective preventative and therapeutic strategies to treat OM.

Impact of triptolide during ex vivo lung perfusion on grafts after transplantation in a rat model

OBJECTIVE

Ex vivo lung perfusion creates a proinflammatory environment leading to deterioration in graft quality that may contribute to post-transplant graft dysfunction. Triptolide has been shown to have a therapeutic potential in various disease states because of its anti-inflammatory properties. On this basis, we investigated the impact of triptolide on graft preservation during ex vivo lung perfusion and associated post-transplant outcomes in a rat transplant model.

METHODS

We performed rat normothermic ex vivo lung perfusion with acellular Steen solution containing 100 nM triptolide for 4 hours and compared the data with untreated lungs. Orthotopic single lung transplantation after ex vivo lung perfusion was performed.

RESULTS

Physiologic and functional parameters of lung grafts on ex vivo lung perfusion with triptolide were better than those without treatment. Graft glucose consumption was significantly attenuated on ex vivo lung perfusion with triptolide via inhibition of hypoxia signaling resulting in improved mitochondrial function and reduced oxidative stress. Also, intragraft inflammation was markedly lower in triptolide-treated lungs because of inhibition of nuclear factor-κB signaling. Furthermore, post-transplant graft function and inflammatory events were significantly improved in the triptolide group compared with the untreated group.

CONCLUSIONS

Treatment of lung grafts with triptolide during ex vivo lung perfusion may serve to enhance graft preservation and improve graft protection resulting in better post-transplant outcomes.

Forgotten Fibrocytes: A Neglected, Supporting Cell Type of the Cochlea With the Potential to be an Alternative Therapeutic Target in Hearing Loss

Cochlear fibrocytes are a homeostatic supporting cell type embedded in the vascularized extracellular matrix of the spiral ligament, within the lateral wall. Here, they participate in the connective tissue syncytium that enables potassium recirculation into the scala media to take place and ensures development of the endolymphatic potential that helps drive current into hair cells during acoustic stimulation. They have also been implicated in inflammatory responses in the cochlea. Some fibrocytes interact closely with the capillaries of the vasculature in a way which suggests potential involvement, together with the stria vascularis, also in the blood-labyrinth barrier. Several lines of evidence suggests that pathology of the fibrocytes, along with other degenerative changes in this region, contribute to metabolic hearing loss (MHL) during aging that is becoming recognized as distinct from, and potentially a precursor for, sensorineural hearing loss (SNHL). This pathology may underlie a significant proportion of cases of presbycusis. Some evidence points also to an association between fibrocyte degeneration and Ménière’s disease (MD). Fibrocytes are mesenchymal; this characteristic, and their location, make them amenable to potential cell therapy in the form of cell replacement or genetic modification to arrest the process of degeneration that leads to MHL. This review explores the properties and roles of this neglected cell type and suggests potential therapeutic approaches, such as cell transplantation or genetic engineering of fibrocytes, which could be used to prevent this form of presbycusis or provide a therapeutic avenue for MD.

An Overview of the Potential Therapeutic Applications of CO-Releasing Molecules

Carbon monoxide (CO) has long been known as the “silent killer” owing to its ability to form carboxyhemoglobin—the main cause of CO poisoning in humans. Its role as an endogenous neurotransmitter, however, was suggested in the early 1990s. Since then, the biological activity of CO has been widely examined via both the direct administration of CO and in the form of so-called “carbon monoxide releasing molecules (CORMs).” This overview will explore the general physiological effects and potential therapeutic applications of CO when delivered in the form of CORMs.

HMBOX1 in hepatocytes attenuates LPS/D-GalN-induced liver injury by inhibiting macrophage infiltration and activation

The HMBOX1 (Homeobox Containing 1) gene was first isolated from the human pancreatic cDNA libraries and is widely expressed in many tissues. Previously, we detected high expression of HMBOX1 in the liver, but its function was unclear. In this study, hepatocyte-specific HMBOX1 knockout mice (Hm^△hep mice) were generated and used to characterize the function of HMBOX1 in the LPS/D-GalN-induced acute liver failure model. HMBOX1-knockout exhibits exacerbated liver injury induced by LPS/D-GalN, accompanied with high levels of inflammatory cytokines both in the liver and in circulation. Further investigation demonstrated that HMBOX1 negatively regulates NF-κB signal transduction. Therefore, HMBOX1-knockout in hepatocytes promotes CCL2 expression through the activation of NF-κB signaling, which enhanced the infiltration of macrophages into the liver. In addition, the decrease of HMBOX1 in hepatocytes promotes the activation of macrophages, upregulating CD80 and MHCⅡ, as well as inflammatory factors TNF-α and IL-6. Importantly, overexpression of HMBOX1 rescued liver injury in Hm^△hep mice. These findings indicate that HMBOX1 in hepatocytes acts as a key immunosuppressive factor for inflammation and plays a critical protective role in LPS/D-GalN-induced liver injury.

Interleukin-10 Attenuates Hypochlorous Acid-Mediated Cytotoxicity to HEI-OC1 Cochlear Cells

Inflammatory reaction plays a crucial role in the pathophysiology of acquired hearing loss such as ototoxicity and labyrinthitis. In our earlier work, we showed the pivotal role of otic fibrocytes in cochlear inflammation and the critical involvement of proinflammatory cytokines in cisplatin ototoxicity. We also demonstrated that otic fibrocytes inhibit monocyte chemoattractant protein 1 (CCL2) upregulation in response to interleukin-10 (IL-10) via heme oxygenase 1 (HMOX1) signaling, resulting in suppression of cochlear inflammation. However, it is still unclear how IL-10 affects inflammation-mediated cochlear injury. Here we aim to determine how hypochlorous acid, a model inflammation mediator affects cochlear cell viability and how IL-10 affects hypochlorous acid-mediated cochlear cell injury. NaOCl, a sodium salt of hypochlorous acid (HOCl) was found to induce cytotoxicity of HEI-OC1 cells in a dose-dependent manner. Combination of hydrogen peroxide and myeloperoxidase augmented cisplatin cytotoxicity, and this synergism was inhibited by N-Acetyl-L-cysteine and ML-171. The rat spiral ligament cell line (RSL) appeared to upregulate the antioxidant response element (ARE) activities upon exposure to IL-10. RSL cells upregulated the expression of NRF2 (an ARE ligand) and NR0B2 in response to CoPP (a HMOX1 inducer), but not to ZnPP (a HMOX1 inhibitor). Adenovirus-mediated overexpression of NR0B2 was found to suppress CCL2 upregulation. IL-10-positive cells appeared in the mouse stria vascularis 1 day after intraperitoneal injection of lipopolysaccharide (LPS). Five days after injection, IL-10-positive cells were observed in the spiral ligament, spiral limbus, spiral ganglia, and suprastrial area, but not in the stria vascularis. IL-10R1 appeared to be expressed in the mouse organ of Corti as well as HEI-OC1 cells. HEI-OC1 cells upregulated Bcl-xL expression in response to IL-10, and IL-10 was shown to attenuate NaOCl-induced cytotoxicity. In addition, HEI-OC1 cells upregulated IL-22RA upon exposure to cisplatin, and NaOCl cytotoxicity was inhibited by IL-22. Taken together, our findings suggest that hypochlorous acid is involved in cochlear injury and that IL-10 potentially reduces cochlear injury through not only inhibition of inflammation but also enhancement of cochlear cell viability. Further studies are needed to determine immunological characteristics of intracochlear IL-10-positive cells and elucidate molecular mechanisms involved in the otoprotective activity of IL-10.

Oral IL-10 suppresses colon carcinogenesis via elimination of pathogenicCD4+ T-cells and induction of antitumor CD8+ T-cell activity

An oral sustained-release formulation of Interleukin-10 suppressed tumor growth and enhanced survival in the APC^min/+/Bacteroides fragilis spontaneous colon cancer model. Therapeutic benefit was associated with a 5-fold reduction in CD4⁺RORγt⁺Foxp3^-IL-17⁺ T-helper cell, CD4⁺RORγt⁺Foxp3⁺IL-17⁺ pathogenic T-regulatory cell and CD4⁺RORγt^-Foxp3⁺IL-17^- conventional T-regulatory cell numbers and a concurrent 2-fold enhancement in CD8⁺ T-cell activity in the colon. Selective subset depletion and functional blockade studies demonstrated that at steady-state CD4⁺RORγt⁺IL-17⁺ T-cell subsets and CD4⁺Foxp3⁺ cTreg supported tumorigenesis, whereas CD8⁺ cytotoxic T-lymphocytes impeded tumor progression following IL-10 therapy. Suppression of tumor growth by CD8⁺ T-cells was associated with enhanced tumor infiltration and cytotoxic granule exocytosis. These findings establish the utility of oral IL-10 as a potential new therapeutic in the management of colon cancer and shed light on the cellular mechanisms that underlie its antitumor activity.

Panel 3: Genetics and Precision Medicine of Otitis Media

Objective The objective is to perform a comprehensive review of the literature up to 2015 on the genetics and precision medicine relevant to otitis media. Data Sources PubMed database of the National Library of Medicine. Review Methods Two subpanels were formed comprising experts in the genetics and precision medicine of otitis media. Each of the panels reviewed the literature in their respective fields and wrote draft reviews. The reviews were shared with all panel members, and a merged draft was created. The entire panel met at the 18th International Symposium on Recent Advances in Otitis Media in June 2015 and discussed the review and refined the content. A final draft was made, circulated, and approved by the panel members. Conclusion Many genes relevant to otitis media have been identified in the last 4 years in advancing our knowledge regarding the predisposition of the middle ear mucosa to commensals and pathogens. Advances include mutant animal models and clinical studies. Many signaling pathways are involved in the predisposition of otitis media. Implications for Practice New knowledge on the genetic background relevant to otitis media forms a basis of novel potential interventions, including potential new ways to treat otitis media.

Panel 4: Report of the Microbiology Panel

Objective To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources PubMed database of the National Library of Medicine. Review Methods Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.

Toll-like receptor ligands induce cytokine and chemokine production in human inner ear endolymphatic sac fibroblasts

OBJECTIVE

Against recent reports concerning cytokine or chemokine in mouse or rat inner ear cells, it is almost unknown whether human inner ear cells would produce cytokine or chemokine. We have for the first time established the human inner-ear-derived fibroblasts from endolymphatic sac.

METHODS

The expression levels of Toll-like receptors (TLRs) in human endolymphatic sac fibroblasts, and the effect on cytokine or chemokine production of the TLR ligands have been examined. To demonstrate the intracellular pathways involved in the regulation of cytokine-production, we used specific inhibitors of c-Jun N-terminal kinase (JNK), extracellular signal-related kinase (ERK), p38 mitogen-activated protein kinase (p38 MAPK)-signaling and N-acetyl-l-cysteine (NAC).

RESULTS

TLR 2, 3, 4 and 9 were highly expressed in human endolymphatic sac fibroblasts. The TLR 3 ligand, polyinosinic-polycytidylic acid (poly(I:C)) significantly enhanced the secretion of thymic stromal lymphopoietin (TSLP), B lymphocyte stimulator (BLyS), IFNγ-inducible protein 10 (IP-10), and macrophage inflammatory protein 1 alpha (MIP-1α) from the cells. The inhibitor of JNK strongly reduced the poly(I:C)-induced TSLP-production. The antioxidant drug, NAC also reduced the TSLP-production in fibroblasts stimulated with poly(I:C).

CONCLUSION

Our findings suggest human inner-ear-endolymphatic sac derived fibroblasts can produce the cytokine and chemokine in response to TLR ligands and play a certain role during the initiation of an immune response.

Biology and pathobiology of lipid droplets and their potential role in the protection of the organ of Corti

The current review article seeks to extend our understanding on the role of lipid droplets within the organ of Corti. In addition to presenting an overview of the current information about the origin, structure and function of lipid droplets we draw inferences from the collective body of knowledge about this cellular organelle to build a conceptual framework to better understanding their role in auditory function. This conceptual model considers that lipid droplets play a significant role in the synthesis, storage, and release of lipids and proteins for energetic use and/or modulating cell signaling pathways. We describe the role and mechanism by which LD play a role in human diseases, and we also review emerging data from our laboratory revealing the potential role of lipid droplets from Hensen cells in the auditory organ. We suggest that lipid droplets might help to develop rapidly and efficiently the resolution phase of inflammatory responses in the mammalian cochlea, preventing inflammatory damage of the delicate inner ear structures and, consequently, sensorineural hearing loss.