miR-431 secreted by human vestibular schwannomas increases the mammalian inner ear's vulnerability to noise trauma.

Introduction: Vestibular schwannoma (VS) is an intracranial tumor that arises on the vestibular branch of cranial nerve VIII and typically presents with sensorineural hearing loss (SNHL). The mechanisms of this SNHL are postulated to involve alterations in the inner ear's microenvironment mediated by the genetic cargo of VS-secreted extracellular vesicles (EVs). We aimed to identify the EV cargo associated with poor hearing and determine whether its delivery caused hearing loss and cochlear damage in a mouse model

Methods: VS tissue was collected from routinely resected tumors of patients with good (VS-GH) or poor (VS-PH) pre-surgical hearing measured via pure-tone average and word recognition scores.

Postnatal expression and possible function of RANK and RANKL in the murine inner ear.

The bone encasing the inner ear, known as the otic capsule, is unique because it remodels little postnatally compared to other bones in the body. Previous studies established that osteoprotegerin (OPG) in the inner ear inhibits otic capsule remodeling. OPG acts as a decoy receptor of receptor activator of nuclear factor κB ligand (RANKL) to disrupt the interaction between RANKL and RANK, the primary regulators of bone metabolism.

Proteome of normal human perilymph and perilymph from people with disabling vertigo.

The vast majority of hearing loss, the most common sensory impairment, and vertigo, which commonly causes falls, both reflect underlying dysfunction of inner ear cells. Perilymph sampling can thus provide molecular cues to hearing and balance disorders. While such "liquid biopsy" of the inner ear is not yet in routine clinical practice, previous studies have uncovered alterations in perilymph in patients with certain types of hearing loss.

Hepatocyte nuclear factor-4 alpha in noise-induced cochlear neuropathy.

Noise-induced hearing loss (NIHL) is a problem of profound clinical significance and growing magnitude. Alarmingly, even moderate noise levels, previously assumed to cause only temporary shifts in auditory thresholds ("temporary" NIHL), are now known to cause cochlear synaptopathy and subsequent neuropathy. To uncover molecular mechanisms of this neuropathy, a network analysis of genes reported to have significantly altered expression after temporary threshold shift-inducing noise exposure was performed.

Activation of TRAIL-DR5 pathway promotes sensorineural degeneration in the inner ear.

Tumor necrosis factor (TNF) family cytokines are important mediators of inflammation. Elevated levels of serum TNF-α are associated with human sensorineural hearing loss via poorly understood mechanisms. We demonstrate, for the first time, expression of TNF-related apoptosis-inducing ligand (TRAIL) and its signaling death receptor 5 (DR5) in the murine inner ear and show that exogenous TRAIL can trigger hair cell and neuronal degeneration, which can be partly prevented with DR5-blocking antibodies.

Transactivation of human osteoprotegerin promoter by GATA-3.

Osteoprotegerin (OPG) is a key regulator of bone remodeling. Mutations in OPG are involved in a variety of human diseases. We have shown that cochlear spiral ganglion cells secrete OPG at high levels and lack of OPG causes sensorineural hearing loss in addition to the previously described conductive hearing loss.

Preclinical validation of anti-nuclear factor-kappa B therapy to inhibit human vestibular schwannoma growth.

Vestibular schwannomas (VSs), the most common tumors of the cerebellopontine angle, arise from Schwann cells lining the vestibular nerve. Pharmacotherapies against VS are almost non-existent. Although the therapeutic inhibition of inflammatory modulators has been established for other neoplasms, it has not been explored in VS.

Nonsteroidal anti-inflammatory medications are cytostatic against human vestibular schwannomas.

Vestibular schwannomas (VSs) are the most common tumors of the cerebellopontine angle. Significant clinical need exists for pharmacotherapies against VSs. Motivated by previous findings that immunohistochemical expression of cyclooxygenase 2 (COX-2) correlates with VS growth rate, we investigated the role of COX-2 in VSs and tested COX-2 inhibiting salicylates against VSs.

Loss of osteoprotegerin expression in the inner ear causes degeneration of the cochlear nerve and sensorineural hearing loss.

Osteoprotegerin (OPG) is a key regulator of bone remodeling. Mutations and variations in the OPG gene cause many human diseases that are characterized by not only skeletal abnormalities but also poorly understood hearing loss: Paget's disease, osteoporosis, and celiac disease. To gain insight into the mechanisms of hearing loss in OPG deficiency, we studied OPG knockout (Opg(-/-)) mice.

Proteome of human perilymph.

Current diagnostic tools limit a clinician's ability to discriminate between many possible causes of sensorineural hearing loss. This constraint leads to the frequent diagnosis of the idiopathic condition, leaving patients without a clear prognosis and only general treatment options. As a first step toward developing new diagnostic tools and improving patient care, we report the first use of liquid chromatography-tandem mass-spectrometry (LC-MS/MS) to map the proteome of human perilymph.

Topographic gene expression in the sinonasal cavity of patients with chronic sinusitis with polyps.

Objective: To determine whether variations in gene expression exist at multiple subsites along the sinonasal tract in patients with chronic sinusitis with polyps and in healthy controls.

Study Design: Prospective, controlled study.

Setting: Academic medical center.

DNA damage induces nuclear translocation of parkin.

Parkinson's disease (PD) is the second most common form of human degenerative disorder. Mutation of parkin is one of the most prevalent causes of autosomal recessive PD. Parkin is an E3 ubiquitin ligase that acts on a variety of substrates, resulting in polyubiquitination and degradation by the proteasome or monoubiquitination and regulation of biological activity.

Rescue of alpha-synuclein cytotoxicity by insulin-like growth factors.

While mutation of alpha-synuclein is a cause of autosomal-dominant Parkinson's disease (PD), it is still elusive as to how alpha-synuclein is involved in the pathogenesis of PD. Here, we show that dopamine-dependent accumulation of alpha-synuclein in cultured cells results in apoptosis. Furthermore, activation of insulin-like growth factor 1 (IGF-1) pathway can rescue alpha-synuclein toxicity and suppress alpha-synuclein aggregation through the activation of PI3K/Akt pathways.

Regulation of DNA repair by parkin.

Mutation of parkin is one of the most prevalent causes of autosomal recessive Parkinson's disease (PD). Parkin is an E3 ubiquitin ligase that acts on a variety of substrates, resulting in polyubiquitination and degradation by the proteasome or monoubiquitination and regulation of biological activity. However, the cellular functions of parkin that relate to its pathological involvement in PD are not well understood.

Gene regulation and DNA damage in the ageing human brain.

The ageing of the human brain is a cause of cognitive decline in the elderly and the major risk factor for Alzheimer's disease. The time in life when brain ageing begins is undefined. Here we show that transcriptional profiling of the human frontal cortex from individuals ranging from 26 to 106 years of age defines a set of genes with reduced expression after age 40.

Dopamine-dependent neurotoxicity of alpha-synuclein: a mechanism for selective neurodegeneration in Parkinson disease.

The mechanism by which dopaminergic neurons are selectively lost in Parkinson disease (PD) is unknown. Here we show that accumulation of alpha-synuclein in cultured human dopaminergic neurons results in apoptosis that requires endogenous dopamine production and is mediated by reactive oxygen species. In contrast, alpha-synuclein is not toxic in non-dopaminergic human cortical neurons, but rather exhibits neuroprotective activity.