MiR-182-5p protects inner ear hair cells from cisplatin-induced apoptosis by inhibiting FOXO3a

Epigenetic Modifications in Sensorineural Hearing Loss: Protective Mechanisms and Therapeutic Potential

Hearing loss, which currently affects more than 430 million individuals globally and is projected to exceed 700 million by 2050, predominantly manifests as sensorineural hearing loss (SNHL), for which existing technologies such as hearing aids and cochlear implants fail to restore natural auditory function. Research focusing on protecting inner ear hair cells (HCs) from harmful factors through the regulation of epigenetic modifications has gained significant attention in otology for its role in regulating gene expression without altering the DNA sequence, suggesting potential strategies for preventing and treating SNHL. By synthesizing relevant studies on the inner ear, this review summarizes the emerging roles of histone modifications, DNA methylation, and noncoding RNAs in HC damage, with a focus on their therapeutic potential through epigenetic modulation. Moreover, this review examines the therapeutic potential of epigenetic regulation for the prevention and treatment of SNHL, emphasizing the application of small-molecule epigenetic compounds and their efficacy in modulating gene expression to preserve and restore auditory function.

Assessment of miR-19b-3p, miR-182-5p, and miR-155-5p expression and its relation

Alopecia areata (AA) is an autoimmune disorder characterized by non-scarring hair loss. Despite the growing understanding of its immune-related pathogenesis, biomarkers for early diagnosis and disease severity assessment remain limited. Recent studies have suggested that microRNAs (miRNAs) play a crucial role in regulating immune responses and inflammation in autoimmune diseases. This study aimed to investigate the expression levels of three miRNAs, miR-19b-3p, miR-182-5p, and miR-155-5p, in AA patients and their potential as diagnostic markers and indicators of disease severity. A total of 67 AA patients and 62 healthy controls were included in this case-control study. The severity of AA was evaluated using the Severity of Alopecia Tool (SALT) score, categorizing patients into mild, moderate, and severe groups. Plasma miRNA extraction was performed using the Direct-zol™ RNA MiniPrep kit, and qRT-PCR analysis was conducted to quantify the expression levels of miR-19b-3p, miR-182-5p, and miR-155-5p. Diagnostic accuracy was assessed using Receiver Operating Characteristic (ROC) curve analysis, and correlation analysis was performed to examine the relationship between miRNA expression and disease severity. The results revealed that the expression of miR-19b-3p, miR-182-5p, and miR-155-5p was significantly higher in AA patients compared to healthy controls (p = 0.001 for all three miRNAs). ROC curve analysis demonstrated high diagnostic accuracy, with AUC values of 0.99 for miR-19b-3p, 0.95 for miR-182-5p, and 0.97 for miR-155-5p. These miRNAs showed high sensitivity and specificity, indicating their strong potential as diagnostic biomarkers. Moreover, correlation analysis revealed a significant association between miR-155-5p expression and the severity of AA (p < 0.001), suggesting its potential as a marker of disease progression. This study highlights the significant upregulation of miR-19b-3p, miR-182-5p, and miR-155-5p in AA patients, indicating their potential as minimally invasive diagnostic markers. Furthermore, the correlation between miRNA expression and disease severity provides valuable insights into the molecular mechanisms underlying AA. These findings suggest that miRNAs, particularly miR-155-5p, may serve as promising biomarkers for diagnosing and monitoring the progression of AA, potentially aiding in the development of targeted therapeutic strategies.

Unraveling the ncRNA landscape that governs colorectal cancer: A roadmap to personalized therapeutics

Colorectal cancer (CRC) being one of the most common malignancies, has a significant death rate, especially when detected at an advanced stage. In most cases, the fundamental aetiology of CRC remains unclear despite the identification of several environmental and intrinsic risk factors. Numerous investigations, particularly in the last ten years, have indicated the involvement of epigenetic variables in this type of cancer. The development, progression, and metastasis of CRC are influenced by long non-coding RNAs (lncRNAs), which are significant players in the epigenetic pathways. LncRNAs are implicated in diverse pathological processes in CRC, such as liver metastasis, epithelial to mesenchymal transition (EMT), inflammation, and chemo-/radioresistance. It has recently been determined that CRC cells and tissues exhibit dysregulation of tens of oncogenic and tumor suppressor lncRNAs. Serum samples from CRC patients exhibit dysregulated expressions of several of these transcripts, offering a non-invasive method of detecting this kind of cancer. In this review, we outlined the typical paradigms of the deregulated lncRNA which exert significant role in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the role of lncRNAs as innovative targets for CRC prognosis and treatment.

Modulating the unfolded protein response with ISRIB mitigates cisplatin ototoxicity

Cisplatin is a commonly used chemotherapy agent with a nearly universal side effect of sensorineural hearing loss. The cellular mechanisms underlying cisplatin ototoxicity are poorly understood. Efforts in drug development to prevent or reverse cisplatin ototoxicity have largely focused on pathways of oxidative stress and apoptosis. An effective treatment for cisplatin ototoxicity, sodium thiosulfate (STS), while beneficial when used in standard risk hepatoblastoma, is associated with reduced survival in disseminated pediatric malignancy, highlighting the need for more specific drugs without potential tumor protective effects. The unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways have been shown to be involved in the pathogenesis of noise-induced hearing loss and cochlear synaptopathy in vivo, and these pathways have been implicated broadly in cisplatin cytotoxicity. This study sought to determine whether the UPR can be targeted to prevent cisplatin ototoxicity. Neonatal cochlear cultures and HEK cells were exposed to cisplatin, and UPR marker gene expression and cell death measured. Treatment with ISRIB (Integrated Stress Response InhIBitor), a drug that activates eif2B and downregulates the pro-apoptotic PERK/CHOP pathway of the UPR, was tested for its ability to reduce apoptosis in HEK cells, hair-cell death in cochlear cultures, and hearing loss using an in vivo mouse model of cisplatin ototoxicity. Finally, to evaluate whether ISRIB might interfere with cisplatin chemoeffectiveness, we tested it in head and neck squamous cell carcinoma (HNSCC) cell-based assays of cisplatin cytotoxicity. Cisplatin exhibited a biphasic, non-linear dose-response of cell death and apoptosis that correlated with different patterns of UPR marker gene expression in HEK cells and cochlear cultures. ISRIB treatment protected against cisplatin-induced hearing loss and hair-cell death, but did not impact cisplatin's cytotoxic effects on HNSCC cell viability, unlike STS. These findings demonstrate that targeting the pro-apoptotic PERK/CHOP pathway with ISRIB can mitigate cisplatin ototoxicity without reducing anti-cancer cell effects, suggesting that this may be a viable strategy for drug development.

Apoptosis, autophagy, ferroptosis, and pyroptosis in cisplatin-induced ototoxicity and protective agents

Cisplatin is widely used to treat various solid tumors. However, its toxicity to normal tissues limits its clinical application, particularly due to its ototoxic effects, which can result in hearing loss in patients undergoing chemotherapy. While significant progress has been made in preclinical studies to elucidate the cellular and molecular mechanisms underlying cisplatin-induced ototoxicity (CIO), the precise mechanisms remain unclear. Moreover, the optimal protective agent for preventing or mitigating cisplatin-induced ototoxicity has yet to be identified. This review summarizes the current understanding of the roles of apoptosis, autophagy, ferroptosis, pyroptosis, and protective agents in cisplatin-induced ototoxicity. A deeper understanding of these cell death mechanisms in the inner ear, along with the protective agents, could facilitate the translation of these agents into clinical therapeutics, help identify new therapeutic targets, and provide novel strategies for cisplatin-based cancer treatment.

Modulating the Unfolded Protein Response with ISRIB Mitigates Cisplatin Ototoxicity

Cisplatin is a commonly used chemotherapy agent with a nearly universal side effect of sensorineural hearing loss. The cellular mechanisms underlying cisplatin ototoxicity are poorly understood. Efforts in drug development to prevent or reverse cisplatin ototoxicity have largely focused on pathways of oxidative stress and apoptosis. An effective treatment for cisplatin ototoxicity, sodium thiosulfate (STS), while beneficial when used in standard risk hepatoblastoma, is associated with reduced survival in disseminated pediatric malignancies, highlighting the need for more specific drugs without potential tumor protective effects. The unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways have been shown to be involved in the pathogenesis of noise-induced hearing loss and cochlear synaptopathy in vivo, and these pathways have been implicated broadly in cisplatin cytotoxicity. This study sought to determine whether the UPR can be targeted to prevent cisplatin ototoxicity. Neonatal cochlear cultures and HEK cells were exposed to cisplatin and UPR-modulating drugs, and UPR marker gene expression and cell death measured. Treatment with ISRIB, a drug that activates eif2B and downregulates the pro-apoptotic PERK/CHOP pathway of the UPR, was tested in an in vivo mouse model of cisplatin ototoxicity and well as a head and neck squamous cell carcinoma (HNSCC) cell-based assay of cisplatin cytotoxicity. Cisplatin exhibited a biphasic, non-linear dose-response of cell death and apoptosis that correlated with different patterns of UPR marker gene expression in HEK cells and cochlear cultures. ISRIB treatment protected against cisplatin-induced hearing loss and hair-cell death, but did not impact the cytotoxic effects of cisplatin on HNSCC cell viability, unlike STS. These findings demonstrate that targeting the pro-apoptotic PERK/CHOP pathway with ISRIB can mitigate cisplatin ototoxicity without reducing anti-cancer cell effects, suggesting that this may be a viable strategy for drug development.

NcRNA: key and potential in hearing loss

Hearing loss has an extremely high prevalence worldwide and brings incredible economic and social burdens. Mechanisms such as epigenetics are profoundly involved in the initiation and progression of hearing loss and potentially yield definite strategies for hearing loss treatment. Non-coding genes occupy 97% of the human genome, and their transcripts, non-coding RNAs (ncRNAs), are widely participated in regulating various physiological and pathological situations. NcRNAs, mainly including micro-RNAs (miRNAs), long-stranded non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in the regulation of cell metabolism and cell death by modulating gene expression and protein-protein interactions, thus impacting the occurrence and prognosis of hearing loss. This review provides a detailed overview of ncRNAs, especially miRNAs and lncRNAs, in the pathogenesis of hearing loss. We also discuss the shortcomings and issues that need to be addressed in the study of hearing loss ncRNAs in the hope of providing viable therapeutic strategies for the precise treatment of hearing loss.

Bile Acid Application in Cell-Targeting for Molecular Receptors in Relation to Hearing: A Comprehensive Review

Bile acids play important roles in the human body, and changes in their pool can be used as markers for various liver pathologies. In addition to their functional effects in modulating inflammatory responses and cellular survivability, the unconjugated or conjugated, secondary, or primary nature of bile acids accounts for their various ligand effects. The common hydrophilic bile acids have been used successfully as local treatment to resolve drug-induced cell damage or to ameliorate hearing loss. From various literature references, bile acids show concentration and tissue-dependent effects. Some hydrophobic bile acids act as ligands modulating vitamin D receptors, muscarinic receptors, and calcium-activated potassium channels, important proteins in the inner ear system. Currently, there are limited resources investigating the therapeutic effects of bile acid on hearing loss and little to no information on detecting bile acids in the remote ear system, let alone baseline bile acid levels and their prevalence in healthy and disease conditions. This review presents both hydrophilic and hydrophobic human bile acids and their tissue-specific effects in modulating cellular integrity, thus considering the possible effects and extended therapeutic applicability of bile acids to the inner ear tissue.

Innovative lanthanide complexes: Shaping the future of cancer/ tumor chemotherapy

Developing new therapeutic and diagnostic metals and metal complexes is a stunning example of how inorganic chemistry is rapidly becoming an essential part of modern medicine. More study of bio-coordination chemistry is needed to improve the design of compounds with fewer harmful side effects. Metal-containing drugs are widely utilized in the treatment of cancer. Platinum complexes are effective against some cancers, but new coordination compounds are being created with improved pharmacological properties and a broader spectrum of anticancer action. The coordination complexes of the 15 lanthanides or rare earth elements in the periodic table are crucial for diagnosing and treating cancer. Understanding and treating cancer requires the detection of binding lanthanide (III) ions or complexes to DNA and breaking DNA by these complexes. Current advances in lanthanide-based coordination complexes as anticancer treatments over the past five years are discussed in this study.

Berberine chloride protects cochlear hair cells from aminoglycoside-induced ototoxicity by reducing the accumulation of mitochondrial reactive oxygen species

Aminoglycoside, a medicinal category of antibiotics, are used in treatment of Gram-negative bacterial infections. Although they are the most widely-used antibiotics due to their high efficacy and low cost, several main adverse effects have been reported including nephrotoxicity and ototoxicity. Since drug-induced ototoxicity is one of the major etiological causes of acquired hearing loss, we examined cochlear hair cell damages caused by three aminoglycosides (amikacin, kanamycin, and gentamicin), and investigated protective property of an isoquinoline-type alkaloid, Berberine chloride (BC). Berberine, a well-known bioactive compound found from medicinal plants, has been known to have anti-inflammatory, antimicrobial effects. To determine protective effect of BC in aminoglycoside-induced ototoxicity, hair cell damages in aminoglycoside- and/or BC-treated hair cells using ex vivo organotypic culture system of mouse cochlea. Mitochondrial ROS levels and depolarization of mitochondrial membrane potential were analyzed, and TUNEL assay and immunostaining of cleaved caspase-3 were performed to detect apoptosis signals. As the results, it was found that BC significantly prevented aminoglycoside-induced hair cell loss and stereocilia degeneration by inhibiting excessive accumulation of mitochondrial ROS and subsequent loss of mitochondrial membrane potential. It eventually inhibited DNA fragmentation and caspase-3 activation, which were significant for all three aminoglycosides. This study is the first report suggested the preventative effect of BC against aminoglycoside-induced ototoxicity. Our data also suggests a possibility that BC has the potential to exert a protective effect against ototoxicity caused by various ototoxic drugs leading to cellular oxidative stress, not limited to aminoglycoside antibiotics.

Antitumor activity of synthetic three copper(II) complexes with terpyridine ligands

Three new synthetic terpyridine copper(II) complexes were characterized. The copper(II) complexes induced apoptosis of three cancer cell lines and arrested T-24 cell cycle in G1 phase. The complexes were accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential. The complexes increased both intracellular ROS and Ca²⁺ levels and activated the caspase-3/9 expression. The apoptosis was further confirmed by Western Blotting analysis. Bcl-2 was down-regulated and Bax was upregulated after treatment with complexes 1-3. The in vivo studies showed that complexes 1-3 obviously inhibited the growth of tumor without significant toxicity to other organs.

Elucidation of the mechanism of miR‑122‑5p in mediating FOXO3 injury and apoptosis of mouse cochlear hair cells induced by hydrogen peroxide

Unveiling the mechanism of miR-122-5p in the mediation of forkhead box O3 (FOXO3) in regards to cochlear hair cell damage provides an effective solution for the treatment of ear hearing disorders. An oxidative stress model using a mouse cochlear hair cell line (HEI-OC1) was established via hydrogen peroxide (H₂O₂). Then HEI-OC1 cells were transfected with miR-122-5p mimic, miR-122-5p inhibitor, and lentiviral vector FOXO3-WT/MUT. Cell viability and apoptosis rate were determined by MTT assay and flow cytometry. Reactive oxygen species (ROS) were observed by confocal laser scanning microscopy. Bcl-2, Bax, capase-3 and c-caspase-9 levels were quantified by western blot analysis and quantitative reverse transcription polymerase chain reaction (RT-qPCR). Enzyme-linked immunosorbent assay (ELISA) was used to detect superoxide dismutase (SOD) and malondialdehyde (MDA) levels, and flow cytometry was performed to measure the mitochondrial membrane potential levels. In the HEI-OC1 oxidative stress model after transfection, the miR-122-5p level was decreased, whereas the FOXO3 level was increased, Moreover, the increased FOXO3 level diminished the cell viability, but promoted cell apoptosis. Apart from this, the Bcl-2 level was downregulated, while levels of Bax, c-caspase-3, c-caspase-9, ROS and MDA were upregulated. Meanwhile, the mitochondrial membrane potential level was also elevated. Overexpression of miR-122-5p was able to partially offset the effects of FOXO3 in the H₂O₂-treated HEI-OC1 cells. Collectively, miR-122-5p restrained the decrease in HEI-OC1 cell viability and apoptosis induced by treatment with H₂O₂.

Ginsenoside Rb1 Attenuates Triptolide-Induced Cytotoxicity in HL-7702 Cells via the Activation of Keap1/Nrf2/ARE Pathway

Triptolide (TP) is the major bioactive compound extracted from Tripterygium wilfordii Hook F. It exerts anti-inflammatory, antirheumatic, antineoplastic, and neuroprotective effects. However, the severe hepatotoxicity induced by TP limits its clinical application. Ginsenoside Rb1 has been reported to possess potential hepatoprotective effects, but its mechanism has not been fully investigated. This study was aimed at investigating the effect of ginsenoside Rb1 against TP-induced cytotoxicity in HL-7702 cells, as well as the underlying mechanism. The results revealed that ginsenoside Rb1 effectively reversed TP-induced cytotoxicity in HL-7702 cells. Apoptosis induced by TP was suppressed by ginsenoside Rb1 via inhibition of death receptor-mediated apoptotic pathway and mitochondrial-dependent apoptotic pathway. Pretreatment with ginsenoside Rb1 significantly reduced Bax/Bcl-2 ratio and down-regulated the expression of Fas, cleaved poly ADP-ribose polymerase (PARP), cleaved caspase-3, and -9. Furthermore, ginsenoside Rb1 reversed TP-induced cell cycle arrest in HL-7702 cells at S and G2/M phase, via upregulation of the expressions of cyclin-dependent kinase 2 (CDK2), cyclin E, cyclin A, and downregulation of the expressions of p53, p21, and p-p53. Ginsenoside Rb1 increased glutathione (GSH) and superoxide dismutase (SOD) levels, but decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Pretreatment with ginsenoside Rb1 enhanced the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), total Nrf2, NAD(P)H: quinone oxidoreductases-1 (NQO-1), heme oxygenase-1 (HO-1), and Kelch-like ECH-associated protein 1 (Keap1)/Nrf2 complex. Therefore, ginsenoside Rb1 effectively alleviates TP-induced cytotoxicity in HL-7702 cells through activation of the Keap1/Nrf2/ARE antioxidant pathway.

Astaxanthine attenuates cisplatin ototoxicity in vitro and protects against cisplatin-induced hearing loss in vivo

Astaxanthine (AST) has important biological activities including antioxidant and anti-inflammatory effects that could alleviate neurological and heart diseases, but its role in the prevention of cisplatin-induced hearing loss (CIHL) is not yet well understood. In our study, a steady interaction between AST and the E3 ligase adapter Kelch-like ECH-associated protein 1, a predominant repressor of nuclear factor erythroid 2-related factor 2 (NRF2), was performed and tested via computer molecular docking and dynamics. AST protected against cisplatin-induced ototoxicity via NRF2 mediated pathway using quantitative PCR and Western blotting. The levels of reactive oxygen species (ROS) and mitochondrial membrane potential revealed that AST reduced ROS overexpression and mitochondrial dysfunction. Moreover, AST exerted anti-apoptosis effects in mouse cochlear explants using immunofluorescence staining and HEI-OC1 cell lines using quantitative PCR and Western blotting. Finally, AST combined with poloxamer was injected into the middle ear through the tympanum, and the protection against CIHL was evaluated using the acoustic brain stem test and immunofluorescent staining in adult mice. Our results suggest that AST reduced ROS overexpression, mitochondrial dysfunction, and apoptosis via NRF2-mediated pathway in cisplatin-exposed HEI-OC1 cell lines and mouse cochlear explants, finally promoting cell survival. Our study demonstrates that AST is a candidate therapeutic agent for CIHL.

Opa1 Prevents Apoptosis and Cisplatin-Induced Ototoxicity in Murine Cochleae

Optic atrophy1 (OPA1) is crucial for inner mitochondrial membrane (IMM) fusion and essential for maintaining crista structure and mitochondrial morphology. Optic atrophy and hearing impairment are the most prevalent clinical features associated with mutations in the OPA1 gene, but the function of OPA1 in hearing is still unknown. In this study, we examined the ability of Opa1 to protect against cisplatin-induced cochlear cell death in vitro and in vivo. Our results revealed that knockdown of Opa1 affects mitochondrial function in HEI-OC1 and Neuro 2a cells, as evidenced by an elevated reactive oxygen species (ROS) level and reduced mitochondrial membrane potential. The dysfunctional mitochondria release cytochrome c, which triggers apoptosis. Opa1 expression was found to be significantly reduced after cell exposed to cisplatin in HEI-OC1 and Neuro 2a cells. Loss of Opa1 aggravated the apoptosis and mitochondrial dysfunction induced by cisplatin treatment, whereas overexpression of Opa1 alleviated cisplatin-induced cochlear cell death in vitro and in explant. Our results demonstrate that overexpression of Opa1 prevented cisplatin-induced ototoxicity, suggesting that Opa1 may play a vital role in ototoxicity and/or mitochondria-associated cochlear damage.

Fursultiamine Prevents Drug-Induced Ototoxicity by Reducing Accumulation of Reactive Oxygen Species in Mouse Cochlea

Drug-induced hearing loss is a major type of acquired sensorineural hearing loss. Cisplatin and aminoglycoside antibiotics have been known to cause ototoxicity, and excessive accumulation of intracellular reactive oxygen species (ROS) are suggested as the common major pathology of cisplatin- and aminoglycoside antibiotics-induced ototoxicity. Fursultiamine, also called thiamine tetrahydrofurfuryl disulfide, is a thiamine disulfide derivative that may have antioxidant effects. To evaluate whether fursultiamine can prevent cisplatin- and kanamycin-induced ototoxicity, we investigated their preventive potential using mouse cochlear explant culture system. Immunofluorescence staining of mouse cochlear hair cells showed that fursultiamine pretreatment reduced cisplatin- and kanamycin-induced damage to both inner and outer hair cells. Fursultiamine attenuated mitochondrial ROS accumulation as evidenced by MitoSOX Red staining and restored mitochondrial membrane potential in a JC-1 assay. In addition, fursultiamine pretreatment reduced active caspase-3 and TUNEL signals after cisplatin or kanamycin treatment, indicating that fursultiamine decreased apoptotic hair cell death. This study is the first to show a protective effect of fursultiamine against cisplatin- and aminoglycoside antibiotics-induced ototoxicity. Our results suggest that fursultiamine could act as an antioxidant and anti-apoptotic agent against mitochondrial oxidative stress.in cochlear hair cells.

Ellagic acid protects rats from chronic renal failure via MiR-182/FOXO3a axis

Studies showed that ellagic acid (EA) can significantly improve kidney function, but the renal-protective effects of EA and the potential mechanism require adequate elucidation. This study investigated the mechanisms of EA in chronic renal failure (CRF) injury. A rat model of CRF was established by 5/6 nephrectomy. The body weight, urine volume and urine protein content of the rat model of CRF with EA treatment (0/20/40 mg/kg/day) were recorded. Hematoxylin&eosin (H&E) staining, Masson staining and TUNEL were used for histopathological observation. Serum levels of creatinine value, blood urea nitrogen, superoxide dismutase, glutathione, malondialdehyde, tumor necrosis factor-α, interleukin-6 and intercellular cell adhesion molecule-1 were determined using enzyme-linked immunosorbent assay (ELISA) kits. The expressions of genes involved in CRF damage were detected by quantitative real-time PCR (qRT-PCR) and western blot. The relationships among EA, miR-182 and FOXO3a were verified by TargetScan 7.2, dual-luciferase assay and rescue experiments. In this study, EA treatment significantly increased the body weight, but reduced urination and urine protein content, renal tissue damage, collagen deposition, inflammation and the contents of serum creatinine (Scr), blood urea nitrogen (BUN), and malondialdehyde (MDA), and improved the antioxidant capacity of CRF rats. Moreover, EA treatment inhibited miR-182, TGF-β1, fibronectin and Bax levels, and promoted those of FOXO3a and Bcl-2 in CRF rats. Additionally, miR-182 specifically targeted FOXO3a, and effectively reduced the renal-protective effect of EA. Further research found that overexpressed FOXO3a partially reversed the inhibitory effect of miR-182 on CRF rats. Our results suggest that EA might reduce CRF injury in rats via miR-182/FOXO3a.

The slc4a2b gene is required for hair cell development in zebrafish

Hair cells (HCs) function as important sensory receptors that can detect movement in their immediate environment. HCs in the inner ear can sense acoustic signals, while in aquatic vertebrates HCs can also detect movements, vibrations, and pressure gradients in the surrounding water. Many genes are responsible for the development of HCs, and developmental defects in HCs can lead to hearing loss and other sensory dysfunctions. Here, we found that the solute carrier family 4, member 2b (slc4a2b) gene, which is a member of the anion-exchange family, is expressed in the otic vesicles and lateral line neuromasts in developing zebrafish embryos. An in silico analysis showed that the slc4a2b is evolutionarily conserved, and we found that loss of function of slc4a2b resulted in a decreased number of HCs in zebrafish neuromasts due to increased HC apoptosis. Taken together, we conclude that slc4a2b plays a critical role in the development of HCs in zebrafish.

Hypoxic Cancer-Secreted Exosomal miR-182-5p Promotes Glioblastoma Angiogenesis by Targeting Kruppel-like Factor 2 and 4

Glioblastoma (GBM) is the most lethal primary brain tumor and has a complex molecular profile. Hypoxia plays a critical role during tumor progression and in the tumor microenvironment (TME). Exosomes released by tumor cells contain informative nucleic acids, proteins, and lipids involved in the interaction between cancer and stromal cells, thus leading to TME remodeling. Accumulating evidence indicates that exosomes play a pivotal role in cell-to-cell communication. However, the mechanism by which hypoxia affects tumor angiogenesis via exosomes derived from tumor cells remains largely unknown. In our study, we found that, compared with the parental cells under normoxic conditions, the GBM cells produced more exosomes, and miR-182-5p was significantly upregulated in the exosomes from GBM cells under hypoxic conditions. Exosomal miR-182-5p directly suppressed its targets Kruppel-like factor 2 and 4, leading to the accumulation of VEGFR, thus promoting tumor angiogenesis. Furthermore, exosome-mediated miR-182-5p also inhibited tight junction-related proteins (such as ZO-1, occludin, and claudin-5), thus enhancing vascular permeability and tumor transendothelial migration. Knockdown of miR-182-5p reduced angiogenesis and tumor proliferation. Interestingly, we found elevated levels circulating miR-182-5p in patient blood serum and cerebrospinal fluid samples, and its expression level was inversely related to the prognosis. IMPLICATIONS: Overall, our data clarify the diagnostic and prognostic value of tumor-derived exosome-mediated miR-182-5p and reveal the distinctive cross-talk between tumor cells and human umbilical vein endothelial cells mediated by tumor-derived exosomes that modulate tumor vasculature.

Exosomes derived from mouse inner ear stem cells attenuate gentamicin-induced ototoxicity in vitro through the miR-182-5p/FOXO3 axis

Gentamicin-induced cochlear hair cell ototoxicity, such as oxidative stress and apoptosis, could be attenuated by mouse inner ear stem cells (IESCs). However, it is still unclear whether such protective effects could be mediated by exosomes derived from IESCs (IESCs-ex). In the present study, HEI-OC1 cells were exposed to gentamicin (2 mM) to establish an ototoxicity model and further treated with exosomes isolated from miR-182-5p transferred or non-transferred IESCs. IESCs-ex improved HEI-OC1 cell viability, as assayed by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide method, and alleviated the oxidative stress response induced by the gentamicin treatment, as confirmed by measuring the malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels. IESCs-ex increased relative miR-182-5p expression and decreased FOXO3 expression in the gentamicin-exposed HEI-OC1 cells. Furthermore, exosomes derived from miR-182-5p mimics that were pre-treated with IESCs could increase miR-182-5p and Bcl-2 expressions and decrease FOXO3 and Bax expressions in gentamicin-exposed HEI-OC1 cells. All of these results indicate that IESCs-ex could attenuate gentamicin-induced HEI-OC1 cell apoptosis and oxidative stress through the miR-182-5p/FOXO3 axis.

miR-182 prevented ototoxic deafness induced by co-administration of kanamycin and furosemide in rats

Ototoxic drugs may induce auditory sensory hair cell loss and permanent deafness; however, there is still no effective treatments or prevention strategies for this side effect. A recent study found that microRNA182 (miR-182) protected cochlear hair cells from ototoxic drug-induced apoptosis in vitro. However, it remains unclear whether miR-182 can protect drug-induced deafness in vivo. In this study, we overexpressed cochlear miR-182 in Sprague-Dawley rats by trans-round window niche delivery of miR-182 mimics. The rats subsequently received intraperitoneal injections of kanamycin and furosemide to induce acute cochlear outer hair cell death and permanent deafness. Auditory brainstem response tests showed that miR-182 attenuated permanent threshold shifts. Consistent with this result, miR-182 reduced the loss of outer hair cells and missing stereocilia. miR-182 treatment also increased the level of phosphoinositide-3 kinase regulatory subunit p85α in the outer hair cells after co-administration of kanamycin and furosemide. Our findings suggest that miR-182 has powerful protective potential against ototoxic drug-induced acute auditory sensory hair cell loss and permanent deafness.

Carbon black nanoparticles induce pulmonary fibrosis through NLRP3 inflammasome pathway modulated by miR-96 targeted FOXO3a

Carbon black nanoparticle (CBNP) is a core constituent of air pollutants like fine particulate matter (PM2.5) as well as a common manufactural material. It was proved to pose adverse effects on lung function and even provoke pulmonary fibrosis. However, the underlying mechanisms of CBNPs-induced pulmonary fibrosis remain unclear. The present study aimed to investigate the mechanism of fibrotic effects caused by CBNPs in rat lung and human bronchial epithelial (16HBE) cells. Forty-nine male rats were randomly subjected to 7 groups, means the 14-day exposure group (30 mg/m3), the 28-day exposure groups (5 mg/m3 and 30 mg/m3), the 90-day exposure group (30 mg/m3) and their respective controls. Rats were nose-only-inhaled CBNPs. 16HBE cells were treated with 0, 50, 100 and 200 μg/mL CBNPs respectively for 24 h. Besides, Forkhead transcription factor class O (FOXO)3a and miR-96 overexpression or suppression 16HBE cells were established to reveal relative mechanisms. Our results suggested CBNPs induced pulmonary fibrosis in time- and dose-dependent manners. CBNPs induced persisting inflammation in rat lung as observed by histopathology and cytology analyses in whole lung lavage fluid (WLL). Both in vivo and in vitro, CBNPs exposure significantly increased the expression of NLRP3 inflammasome, accompanied by the increased reactive oxygen species (ROS), decreased miR-96 and increased FOXO3a expressions dose -and time-dependently. MiR-96 overexpression or FOXO3a suppression could partially rescue the fibrotic effects through inhibiting NLRP3 inflammasome. Conclusively, our research show that CBNPs-induced pulmonary fibrosis was at least partially depended on activation of NLRP3 inflammasome which modulated by miR-96 targeting FOXO3a.

Cisplatin induces calcium ion accumulation and hearing loss by causing functional alterations in calcium channels and exocytosis

In recent years, molecular biology and biochemistry have been a focus of studies on the ototoxic side effects of cisplatin. In this paper, the application of cisplatin for 4 h and 72 h was studied from the perspective of electrophysiological function. Patch clamp experiments and immunofluorescence staining were performed on inner hair cells of the cochlea. The patch-clamp results showed that the calcium current amplitude decreased significantly at 4 h and 72 h after cisplatin treatment, the reversal potential was negatively polarized, and the activation time decreased. We suspected that intracellular calcium accumulation was responsible for this result and confirmed this hypothesis by using calpain to measure intracellular calcium concentrations. We tested membrane capacitive function, whose levels after cisplatin application were significantly lower than those in the control group, thus indicating dysfunctional cytoplasmic effervescent function. CtBP2 staining was used to verify this result and indicated a decrease in ribbon synapses. Simultaneously, we observed dysfunction of vesicle circulation after cisplatin application. We found that cisplatin induces the accumulation of calcium ions in inner hair cells by calpain staining and fluoresce intensity calculation, thus decreasing calcium current and synaptic vesicle release, and impairing vesicles cycling, all of which are important mechanisms of cisplatin-induced hearing loss.

TMPRSS3 regulates cell viability and apoptosis processes of HEI-OC1 cells via regulation of the circ-Slc4a2, miR-182 and Akt cascade

BACKGROUND

The present study aimed to investigate the functions and regulation mechanism of the transmembrane protease, serine 3 (TMPRSS3), which plays an important role in sensorineural hearing loss.

METHODS

House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, comprising auditory-related cells, were used in the present study. An overexpression vector and small hairpin RNA target on TMPRSS3 were designed and transfected into HEI-OC1 cells. Circular RNA (circRNA) sequencing was conducted and expression profiles were obtained. The circular structure of circRNAs was validated with a polymerase chain reaction and Sanger sequencing using convergent and divergent primers.

RESULTS

Overexpression of TMPRSS3 increased cell viability, whereas suppression of TMPRSS3 increased the percentage of apoptotic cells and decreased cell viability, compared to the control group. circRNA sequencing provided expression profiles indicating that the overexpression of TMPRSS3 increased the expression level of 195 circRNAs. Results of GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) studies indicated that the circRNAs are focused on the RAS signaling pathway. The pathway, circ-Slc41a2 (chr10: 82744115|82767120), miR-182 and Akt, might comprise one of the key cascades of TMPRSS3.

CONCLUSIONS

TMPRSS3 is an important molecule in the regulation of cell viability and cell apoptosis of HEI-OC1 cells. Its functions are dependent on the circ-Slc41a2, miR-182 and Akt cascade.

Novel compounds protect auditory hair cells against gentamycin-induced apoptosis by maintaining the expression level of H3K4me2

Aminoglycoside-induced hair cell (HC) loss is a major cause of hearing impairment, and the effective prevention of HC loss remains an unmet medical need. Epigenetic mechanisms have been reported to be involved in protecting cochlear cells against ototoxic drug injury, and in this study we developed new bioactive compounds that have similar chemical structures as the epigenetics-related lysine-specific demethylase 1 (LSD1) inhibitors. LSD1 inhibitors have been reported to protect cochlear cells by preventing demethylation of dimethylated histone H3K4 (H3K4me2). To determine whether these new compounds exert similar protective effects on HCs, we treated mouse cochlear explant cultures with the new compounds together with gentamycin. There was a severe loss of HCs in the organ of Corti after gentamycin exposure, while co-treatment with the new compounds significantly protected against gentamycin-induced HC loss. H3K4me2 levels in the nuclei of HCs decreased after exposure to gentamycin, but H3K4me2 levels were maintained in the presence of the new compounds. Apoptosis is also involved in the injury process, and the new compounds protected the inner ear HCs against apoptosis by reducing caspase-3 activation. Together, our findings demonstrate that our new compounds prevent gentamycin-induced HC loss by preventing the demethylation of H3K4me2 and by inhibiting apoptosis, and these results might provide the theoretical basis for novel drug development for hearing protection.

Differential MicroRNA Expression Profiles as Potential Biomarkers for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a clinical challenge due to its poor prognosis. Therefore, the early diagnosis of PDAC is extremely important for achieving a cure. MicroRNAs (miRNAs) could serve as a potential biomarker for the early detection and prognosis of PDAC. In this work we analyzed plasma samples from healthy persons and PDAC patients to assess differential miRNA expression profiles by next generation sequencing technology and bioinformatics analysis. In this way, 165 mature miRNAs were found to be significantly deregulated in the patient group, of which 75 and 90 mature miRNAs were up- and down-regulated compared with healthy individuals, respectively. Furthermore, 1029 novel miRNAs were identified. In conclusion, plasma miRNA expression profiles are different between healthy individuals and patients with PDAC. These data provide a possibility for use of miRNA as diagnostic and prognostic biomarkers of PDAC.

Role of epigenetic mechanisms in cisplatin-induced toxicity

Cisplatin (CDDP) is a highly effective antineoplastic agent, widely used in the treatment of various malignant tumors. However, its major problems are side effects associated to toxicity. Considerable inter-individual differences have been reported for CDDP-induced toxicity due to genetic and epigenetic factors. Genetic causes are well described; however, epigenetic modifications are not fully addressed. In the last few years, many evidences were found linking microRNA to the development of CDDP-mediated toxicity, particularly nephrotoxicity. In this review, we described how genetic and epigenetic modifications can be important determinants for the development of toxicity in patients treated with CDDP, and how these alterations may be interesting biomarkers for monitoring toxicity induced by CDDP. Considering the validation in different studies, we suggest that miR-34a, -146b, -378a, -192, and -193 represent an attractive study group to evaluate potential biomarkers to detect CDDP-related nephrotoxicity.

Inhibition of miR-182-5p protects cardiomyocytes from hypoxia-induced apoptosis by targeting CIAPIN1

Myocardial infarction (MI), a type of ischemic heart disease, is generally accompanied by apoptosis of cardiomyocytes. MicroRNAs play the vital roles in the development and physiology of MI. Here, we established a downregulation model of miR-182-5p in H9c2 cells under hypoxic conditions to investigate the potential molecular mechanisms for miR-182-5p in hypoxia-induced cardiomyocyte apoptosis (HICA). RT-qPCR indicated that miR-182-5p levels exhibit a time-dependent increase in the rate of apoptosis induced by hypoxia. The results from the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and LDH (lactate dehydrogenase) assays indicated that cardiomyocyte injury noticeably increased after exposure to hypoxia. Meanwhile, hypoxia dramatically increased the apoptosis rate [which was reflected in the results from the annexin V – propidium iodide (PI) assay], enhanced caspase-3 activity, and reduced the expression of Bcl-2. Downregulation of miR-182-5p can significantly reverse hypoxia-induced cardiomyocyte injury or apoptosis. Importantly, bioinformatic analysis and dual-luciferase reporter assay revealed that CIAPIN1 (cytokine-induced apoptosis inhibitor 1) was a direct functional target of miR-182-5p, and that inhibition of miR-182-5p can lead to an increase in CIAPIN1 expression at both the mRNA and protein levels. Furthermore, the knockdown of CIAPIN1 with small interfering RNAs (siRNAs) efficiently abolished the protective effects of miR-182-5p inhibitor on HICA, demonstrating that miR-182-5p plays a pro-apoptotic role in cardiomyocytes under hypoxic conditions by downregulating CIAPIN1. Collectively, our results demonstrate that miR-182-5p may serve an underlying target to prevent cardiomyocytes from hypoxia-induced injury or apoptosis.

Recent advances in understanding the role of FOXO3

The forkhead box O3 (FOXO3, or FKHRL1) protein is a member of the FOXO subclass of transcription factors. FOXO proteins were originally identified as regulators of insulin-related genes; however, they are now established regulators of genes involved in vital biological processes, including substrate metabolism, protein turnover, cell survival, and cell death. FOXO3 is one of the rare genes that have been consistently linked to longevity in in vivo models. This review provides an update of the most recent research pertaining to the role of FOXO3 in (i) the regulation of protein turnover in skeletal muscle, the largest protein pool of the body, and (ii) the genetic basis of longevity. Finally, it examines (iii) the role of microRNAs in the regulation of FOXO3 and its impact on the regulation of the cell cycle.

Syntheses, Crystal Structures, and Antitumor Activities of Copper(II) and Nickel(II) Complexes with 2-((2-(Pyridin-2-yl)hydrazono)methyl)quinolin-8-ol

Two transition metal complexes with 2-((2-(pyridin-2-yl)hydrazono)methyl)quinolin-8-ol (L), [Cu(L)Cl₂]₂ (1) and [Ni(L)Cl₂]·CH₂Cl₂ (2), were synthesized and fully characterized. Complex 1 exhibited high in vitro antitumor activity against SK-OV-3, MGC80-3 and HeLa cells with IC50 values of 3.69 ± 0.16, 2.60 ± 0.17, and 3.62 ± 0.12 μM, respectively. In addition, complex 1 caused cell arrest in the S phase, which led to the down-regulation of Cdc25 A, Cyclin B, Cyclin A, and CDK2, and the up-regulation of p27, p21, and p53 proteins in MGC80-3 cells. Complex 1 induced MGC80-3 cell apoptosis via a mitochondrial dysfunction pathway, as shown by the significantly decreased level of bcl-2 protein and the loss of Δψ, as well as increased levels of reactive oxygen species (ROS), intracellular Ca2+, cytochrome C, apaf-1, caspase-3, and caspase-9 proteins in MGC80-3 cells.

Intracellular Regulome Variability Along the Organ of Corti: Evidence, Approaches, Challenges, and Perspective

The mammalian hearing organ is a regular array of two types of hair cells (HCs) surrounded by six types of supporting cells. Along the tonotopic axis, this conserved radial array of cell types shows longitudinal variations to enhance the tuning properties of basilar membrane. We present the current evidence supporting the hypothesis that quantitative local variations in gene expression profiles are responsible for local cell responses to global gene manipulations. With the advent of next generation sequencing and the unprecedented array of technologies offering high throughput analyses at the single cell level, transcriptomics will become a common tool to enhance our understanding of the inner ear. We provide an overview of the approaches and landmark studies undertaken to date to analyze single cell variations in the organ of Corti and discuss the current limitations. We next provide an overview of the complexity of known regulatory mechanisms in the inner ear. These mechanisms are tightly regulated temporally and spatially at the transcription, RNA-splicing, mRNA-regulation, and translation levels. Understanding the intricacies of regulatory mechanisms at play in the inner ear will require the use of complementary approaches, and most probably, a combinatorial strategy coupling transcriptomics, proteomics, and epigenomics technologies. We highlight how these data, in conjunction with recent insights into molecular cell transformation, can advance attempts to restore lost hair cells.

microRNA-183 is Essential for Hair Cell Regeneration after Neomycin Injury in Zebrafish

PURPOSE

microRNAs (miRNAs) are non-coding RNAs composed of 20 to 22 nucleotides that regulate development and differentiation in various organs by silencing specific RNAs and regulating gene expression. In the present study, we show that the microRNA (miR)-183 cluster is upregulated during hair cell regeneration and that its inhibition reduces hair cell regeneration following neomycin-induced ototoxicity in zebrafish.

MATERIALS AND METHODS

miRNA expression patterns after neomycin exposure were analyzed using microarray chips. Quantitative polymerase chain reaction was performed to validate miR-183 cluster expression patterns following neomycin exposure (500 μM for 2 h). After injection of an antisense morpholino (MO) to miR-183 (MO-183) immediately after fertilization, hair cell regeneration after neomycin exposure in neuromast cells was evaluated by fluorescent staining (YO-PRO1). The MO-183 effect also was assessed in transgenic zebrafish larvae expressing green fluorescent protein (GFP) in inner ear hair cells.

RESULTS

Microarray analysis clearly showed that the miR-183 cluster (miR-96, miR-182, and miR-183) was upregulated after neomycin treatment. We also confirmed upregulated expression of the miR-183 cluster during hair cell regeneration after neomycin-induced ototoxicity. miR-183 inhibition using MO-183 reduced hair cell regeneration in both wild-type and GFP transgenic zebrafish larvae.

CONCLUSION

Our work demonstrates that the miR-183 cluster is essential for the regeneration of hair cells following ototoxic injury in zebrafish larvae. Therefore, regulation of the miR-183 cluster can be a novel target for stimulation of hair cell regeneration.

MicroRNA-182-5p Regulates Nerve Injury–induced Nociceptive Hypersensitivity by Targeting Ephrin Type-b Receptor 1

Background

The authors and others have previously shown that the up-regulation of spinal ephrin type-b receptor 1 plays an essential role in the pathologic process of nerve injury–induced nociceptive hypersensitivity, but the regulatory mechanism remains unclear.

Methods

Radiant heat and von Frey filaments were applied to assess nociceptive behaviors. Real-time quantitative polymerase chain reaction, Western blotting, fluorescence in situ hybridization, immunofluorescence, immunohistochemistry, dual-luciferase reporter gene assays, recombinant lentivirus, and small interfering RNA were used to characterize the likely mechanisms.

Results

Periphery nerve injury induced by chronic constriction injury of the sciatic nerve significantly reduced spinal microRNA-182-5p (miR-182-5p) expression levels, which were inversely correlated with spinal ephrin type-b receptor 1 expression (R2 = 0.90; P &lt; 0.05; n = 8). The overexpression of miR-182-5p in the spinal cord prevented and reversed the nociceptive behaviors induced by sciatic nerve injury, accompanied by a decreased expression of spinal ephrin type-b receptor 1 (recombinant lentiviruses containing pre-microRNA-182: 1.91 ± 0.34 vs. 1.24 ± 0.31, n = 4; miR-182-5p mimic: 2.90 ± 0.48 vs. 1.51 ± 0.25, n = 4). In contrast, the down-regulation of spinal miR-182-5p facilitated the nociceptive behaviors induced by sciatic nerve injury and increased the expression of spinal ephrin type-b receptor 1 (1.0 ± 0.26 vs. 1.74 ± 0.31, n = 4). Moreover, the down-regulation of miR-182-5p and up-regulation of ephrin type-b receptor 1 caused by sciatic nerve injury were mediated by the N-methyl-d-aspartate receptor.

Conclusions

Collectively, our findings reveal that the spinal ephrin type-b receptor 1 is regulated by miR-182-5p in nerve injury–induced nociceptive hypersensitivity.

Amiodarone-Induced Retinal Neuronal Cell Apoptosis Attenuated by IGF-1 via Counter Regulation of the PI3k/Akt/FoxO3a Pathway

Amiodarone (AM) is the most effective antiarrhythmic agent currently available. However, clinical application of AM is limited by its serious toxic adverse effects including optic neuropathy. The purpose of this study was to explore the effects of AM and to assess if insulin-like growth factor-1 (IGF-1) could protect retinal neuronal cells from AM-induced apoptosis, and to determine the molecular mechanisms underlying the effects. Accordingly, the phosphorylation/activation of Akt and FoxO3a were analyzed by Western blot while the possible pathways involved in the protection of IGF-1 were investigated by application of various pathway inhibitors. The full electroretinogram (FERG) was used to evaluate in vivo effect of AM and IGF-1 on rat retinal physiological functions. Our results showed that AM concentration dependently caused an apoptosis of RGC-5 cells, while IGF-1 protected RGC-5 cells against this effect by AM. The protective effect of IGF-1 was reversed by PI3K inhibitors LY294002 and wortmannin as well as the Akt inhibitor VIII. AM decreased p-Akt and p-FoxO3a while increased the nuclear localization of FoxO3a in the RGC-5 cells. IGF-1 reversed the effect of AM on the p-Akt and p-FoxO3a and the nuclear translocation of FoxO3a. Similar results were obtained in primary cultured retinal ganglia cells. Furthermore, FERG in vivo recording in rats showed that AM decreased a-wave and b-wave of FERG while IGF-1 reversed the effects of AM. These data show that AM induced apoptosis of retinal neuronal cells via inhibiting the PI3K/Akt/FoxO3a pathway while IGF-1 protected RGC-5 cells against AM-induced cell apoptosis by stimulating this pathway.