Role and mechanism of FOXG1-related epigenetic modifications in cisplatin-induced hair cell damage

FOXG1 promotes osteogenesis of bone marrow-derived mesenchymal stem cells by activating autophagy through regulating USP14

The osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) is key for bone formation, and its imbalance leads to osteoporosis. Forkhead Box Protein G1 (FOXG1) is associated with osteogenesis, however, the effect of FOXG1 on osteogenesis of BMSCs and ovariectomy (OVX)-induced bone loss is unknown. In our study, FOXG1 expression in BMSCs increases after osteogenic induction. FOXG1 overexpression significantly increases osteoblast marker expression ALP activity, and calcium deposition, while the opposite results are observed in FOXG1 knockdown BMSCs, suggesting that FOXG1 promotes osteogenic differentiation. Additionally, autophagy promotes the differentiation process in BMSCs. We find that FOXG1 induces autophagy, and osteogenic differentiation is blocked via inhibiting FOXG1-caused autophagy, indicating that FOXG1 accelerates osteogenic differentiation via inducing autophagy. Eight-week-old female C57BL/6J mice are used in OVX models, FOXG1 overexpression decreases bone loss by increasing bone formation. Moreover, FOXG1 overexpression suppresses osteoclast differentiation. Mechanically, FOXG1 transcriptionally represses ubiquitin-specific protease14 (USP14) via binding to the USP14 promoter. USP14 overexpression prevents the promoting effect of FOXG1 on osteogenic differentiation in BMSCs. Therefore, our findings suggest that FOXG1 promotes BMSC osteogenic differentiation and inhibits osteoclast differentiation, eventually blocking OVX-induced bone loss, which may provide a promising approach for osteoporosis treatment.

FOXG1 interaction with SATB2 promotes autophagy to alleviate neuroinflammation and mechanical abnormal pain in rats with lumbar disc herniation

BACKGROUND

Most patients with lumbar disc herniation can be relieved or cured by surgical or non-surgical treatment; however, postoperative persistent radiculopathy is common. This study demonstrates the regulation of autophagy by the FOXG1/SATB2 axis in lumbar disc herniation (LDH).

METHODS

Rat dorsal root neurons were induced with TNF-α in vitro. Sprague Dawley (SD) rats were used to construct the LDH rat model, which was treated with L. paracasei S16 or oe-FOXG1. Paw withdrawal threshold or latency assay (PWT/L) was performed. Peripheral blood samples were collected and analysed using ELISA and miRNAseq. RT-qPCR was used to analyse the expression of FOXG1, LC3B, Beclin1, p62, and SATB2. TUNEL staining and flow cytometry were used to analyse apoptosis. The expression of Cyclin D1, PCNA, Ki67, FOXG1, SATB2, and autophagy proteins was measured using western blotting.

RESULTS

TNF-α induced low expression of FOXG1 and SATB2 in dorsal root ganglion (DRG) neurons of rats. TNF-α induced an increase in p62 protein and a decrease in LC3II/I and Beclin-1 proteins in neurons, which were blocked by oe-FOXG1. oe-FOXG1 suppressed inflammation and apoptosis in TNF-α-induced DRG neurons and LDH rats and promoted the expression of Cyclin D1, PCNA, and Ki67. Many miRNAs were increased in the peripheral blood of LDH rats, but decreased after L. paracasei S16 intervention. L. paracasei S16 affects miR-31a-5p and SATB2 expression. Dual luciferase reporter gene assay confirmed that miR-31a-5p bound to SATB2. Co-IP analysis confirmed the interaction between FOXG1 and SATB2. Silencing of SATB2 inhibited the beneficial effects of oe-FOXG1 in TNF-α-induced dorsal root ganglion neurons. Animal experiments further demonstrated that oe-FOXG1 improved LDH disease characteristics by downregulating PWT, PWL, inflammation, and apoptosis levels and upregulating SATB2-autophagy levels.

CONCLUSIONS

MiR-31a-5p/SATB2 is involved in the treatment of L. paracasei S16 in LDH rats. Overexpression of FOXG1 promotes autophagy through SATB2 to improve LDH levels This provides a new approach for the treatment of LDH.

Pharmacological Approaches to Hearing Loss

Hearing disorders pose significant challenges to individuals experiencing them and their overall quality of life, emphasizing the critical need for advanced pharmacological approaches to address these conditions. Current treatment options often focus on amplification devices, cochlear implants, or other rehabilitative therapies, leaving a substantial gap regarding effective pharmacological interventions. Advancements in our understanding of the molecular and cellular mechanisms involved in hearing disorders induced by noise, aging, and ototoxicity have opened new avenues for drug development, some of which have led to numerous clinical trials, with promising results. The development of optimal drug delivery solutions in animals and humans can also enhance the targeted delivery of medications to the ear. Moreover, large genome studies contributing to a genetic understanding of hearing loss in humans combined with advanced molecular technologies in animal studies have shown a great potential to increase our understanding of the etiologies of hearing loss. The auditory system exhibits circadian rhythms and temporal variations in its physiology, its vulnerability to auditory insults, and its responsiveness to drug treatments. The cochlear clock rhythms are under the control of the glucocorticoid system, and preclinical evidence suggests that the risk/benefit profile of hearing disorder treatments using chronopharmacological approaches would be beneficial. If translatable to the bedside, such approaches may improve the outcome of clinical trials. Ongoing research into the molecular and genetic basis of auditory disorders, coupled with advancements in drug formulation and delivery as well as optimized timing of drug administration, holds great promise of more effective treatments. SIGNIFICANCE STATEMENT: Hearing disorders pose significant challenges to individuals and their overall quality of life, emphasizing the critical need for advanced pharmacological approaches to address these conditions. Ongoing research into the molecular and genetic basis of auditory disorders, coupled with advancements in drug delivery procedures and optimized timing of drug administration, holds the promise of more effective treatments.

Hearing loss during chemotherapy: prevalence, mechanisms, and protection

Ototoxicity is an often-underestimated sequela for cancer patients undergoing chemotherapy, with an incidence rate exceeding 50%, affecting approximately 4 million individuals worldwide each year. Despite the nearly 2,000 publications on chemotherapy-related ototoxicity in the past decade, the understanding of its prevalence, mechanisms, and preventative or therapeutic measures remains ambiguous and subject to debate. To date, only one drug, sodium thiosulfate, has gained FDA approval for treating ototoxicity in chemotherapy. However, its utilization is restricted. This review aims to offer clinicians and researchers a comprehensive perspective by thoroughly and carefully reviewing available data and current evidence. Chemotherapy-induced ototoxicity is characterized by four primary symptoms: hearing loss, tinnitus, vertigo, and dizziness, originating from both auditory and vestibular systems. Hearing loss is the predominant symptom. Amongst over 700 chemotherapeutic agents documented in various databases, only seven are reported to induce hearing loss. While the molecular mechanisms of the hearing loss caused by the two platinum-based drugs are extensively explored, the pathways behind the action of the other five drugs are primarily speculative, rooted in their therapeutic properties and side effects. Cisplatin attracts the majority of attention among these drugs, encompassing around two-thirds of the literature regarding ototoxicity in chemotherapy. Cisplatin ototoxicity chiefly manifests through the loss of outer hair cells, possibly resulting from damages directly by cisplatin uptake or secondary effects on the stria vascularis. Both direct and indirect influences contribute to cisplatin ototoxicity, while it is still debated which path is dominant or where the primary target of cisplatin is located. Candidates for hearing protection against cisplatin ototoxicity are also discussed, with novel strategies and methods showing promise on the horizon.

FoxG1/BNIP3 axis promotes mitophagy and blunts cisplatin resistance in osteosarcoma

Cisplatin (CDDP) is a commonly used chemotherapeutic for osteosarcoma (OS) patients, and drug resistance remains as a major hurdle to undermine the treatment outcome. Here, we investigated the potential involvement of FoxG1 and BNIP3 in CDDP resistance of OS cells. FoxG1 and BNIP3 expression levels were detected in the CDDP-sensitive and CDDP-resistant OS tumors and cell lines. Mitophagy was observed through transmission electron microscope analysis. The sensitivity to CDDP in OS cells upon FoxG1 overexpression was examined in cell and animal models. We found that FoxG1 and BNIP3 showed significant downregulation in the CDDP-resistant OS tumor samples and cell lines. CDDP-resistant OS tumor specimens and cells displayed impaired mitophagy. FoxG1 overexpression promoted BNIP3 expression, enhanced mitophagy in CDDP-resistant OS cells, and resensitized the resistant cells to CDDP treatment in vitro and in vivo. Our data highlighted the role of the FoxG1/BNIP3 axis in regulating mitophagy and dictating CDDP resistance in OS cells, suggesting targeting FoxG1/BNIP3-dependent mitophagy as a potential strategy to overcome CDDP resistance in OS.

The Role and Mechanism of the Histone Methyltransferase G9a in Tumors: Update

Methylation-mediated gene silencing is closely related to the occurrence and development of human tumors. The euchromatic histone lysine methyltransferase 2 (EHMT2, also known as G9a) is highly expressed in many tumors and is generally considered to be an oncogene, which is associated with the poor outcome of many tumors. Combined immunotherapy and immune checkpoint blockade therapy also have good efficacy and certain safety. However, there are still many difficulties in the drugs targeting G9a, and the combined effect and safety of G9a with many drugs is still under study. This article aims to summarize the role and mechanism of G9a and its inhibitors in tumors in the past two years, and to understand the application prospect of G9a from the perspective of diagnosis and treatment.

Potential role of modulating autophagy levels in sensorineural hearing loss

In recent years, extensive research has been conducted on the pathogenesis of sensorineural hearing loss (SNHL). Apoptosis and necrosis have been identified to play important roles in hearing loss, but they cannot account for all hearing loss. Autophagy, a cellular process responsible for cell self-degradation and reutilization, has emerged as a significant factor contributing to hearing loss, particularly in cases of autophagy deficiency. Autophagy plays a crucial role in maintaining cell health by exerting cytoprotective and metabolically homeostatic effects in organisms. Consequently, modulating autophagy levels can profoundly impact the survival, death, and regeneration of cells in the inner ear, including hair cells (HCs) and spiral ganglion neurons (SGNs). Abnormal mitochondrial autophagy has been demonstrated in animal models of SNHL. These findings indicate the profound significance of comprehending autophagy while suggesting that our perspective on this cellular process holds promise for advancing the treatment of SNHL. Thus, this review aims to clarify the pathogenic mechanisms of SNHL and the role of autophagy in the developmental processes of various cochlear structures, including the greater epithelial ridge (GER), SGNs, and the ribbon synapse. The pathogenic mechanisms of age-related hearing loss (ARHL), also known as presbycusis, and the latest research on autophagy are also discussed. Furthermore, we underscore recent findings on the modulation of autophagy in SNHL induced by ototoxic drugs. Additionally, we suggest further research that might illuminate the complete potential of autophagy in addressing SNHL, ultimately leading to the formulation of pioneering therapeutic strategies and approaches for the treatment of deafness.

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.

The Relevance of Autophagy within Inner Ear in Baseline Conditions and Tinnitus-Related Syndromes

Tinnitus is the perception of noise in the absence of acoustic stimulation (phantom noise). In most patients suffering from chronic peripheral tinnitus, an alteration of outer hair cells (OHC) starting from the stereocilia (SC) occurs. This is common following ototoxic drugs, sound-induced ototoxicity, and acoustic degeneration. In all these conditions, altered coupling between the tectorial membrane (TM) and OHC SC is described. The present review analyzes the complex interactions involving OHC and TM. These need to be clarified to understand which mechanisms may underlie the onset of tinnitus and why the neuropathology of chronic degenerative tinnitus is similar, independent of early triggers. In fact, the fine neuropathology of tinnitus features altered mechanisms of mechanic-electrical transduction (MET) at the level of OHC SC. The appropriate coupling between OHC SC and TM strongly depends on autophagy. The involvement of autophagy may encompass degenerative and genetic tinnitus, as well as ototoxic drugs and acoustic trauma. Defective autophagy explains mitochondrial alterations and altered protein handling within OHC and TM. This is relevant for developing novel treatments that stimulate autophagy without carrying the burden of severe side effects. Specific phytochemicals, such as curcumin and berberin, acting as autophagy activators, may mitigate the neuropathology of tinnitus.