Opa1 Prevents Apoptosis and Cisplatin-Induced Ototoxicity in Murine Cochleae

Research progress on the role and mechanism of Sirtuin family in doxorubicin cardiotoxicity

BACKGROUND

Doxorubicin (DOX) is a widely utilized anthracycline chemotherapy drug in cancer treatment, yet its efficacy is hindered by both short-term and long-term cardiotoxicity. Although oxidative stress, inflammation and mitochondrial dysfunction are established factors in DOX-induced cardiotoxicity, the precise molecular pathways remain elusive. Further exploration of the pathogenesis and identification of novel molecular targets are imperative. Recent studies have implicated the Sirtuins family in various physiological and pathological processes, suggesting their potential in ameliorating DOX-induced cardiotoxicity. Moreover, research on Sirtuins has discovered small-molecule compounds or medicinal plants with regulatory effects, representing a notable advancement in preventing and treating DOX-induced cardiac injury.

PURPOSE

In this review, we delve into the pathogenesis of DOX-induced cardiotoxicity and explore the therapeutic effects of Sirtuins in mitigating this condition, along with the associated molecular mechanisms. Furthermore, we delineate the roles and mechanisms of small-molecule regulators of Sirtuins in the prevention and treatment of DOX-induced cardiotoxicity.

STUDY-DESIGN/METHODS

Data for this review were sourced from various scientific databases (such as Web of Science, PubMed and Science Direct) up to March 2024. Search terms included "Sirtuins," "DOX-induced cardiotoxicity," "DOX," "Sirtuins regulators," "histone deacetylation," among others, as well as several combinations thereof.

RESULTS

Members of the Sirtuins family regulate both the onset and progression of DOX-induced cardiotoxicity through anti-inflammatory, antioxidative stress and anti-apoptotic mechanisms, as well as by maintaining mitochondrial stability. Moreover, natural plant-derived active compounds such as Resveratrol (RES), curcumin, berberine, along with synthetic small-molecule compounds like EX527, modulate the expression and activity of Sirtuins.

CONCLUSION

The therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity represents a potential molecular target. However, further research is urgently needed to elucidate the relevant molecular mechanisms and to assess the safety and biological activity of Sirtuins regulators. This review offers an in-depth understanding of the therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity, providing a preliminary basis for the clinical application of Sirtuins regulators in this condition.

Personalized Porous Gelatin Methacryloyl Sustained-Release Nicotinamide Protects Against Noise-Induced Hearing Loss

There are no Food and Drug Administration-approved drugs for treating noise-induced hearing loss (NIHL), reflecting the absence of clear specific therapeutic targets and effective delivery strategies. Noise trauma is demonstrated results in nicotinamide adenine dinucleotide (NAD+) downregulation and mitochondrial dysfunction in cochlear hair cells (HCs) and spiral ganglion neurons (SGNs) in mice, and NAD+ boosted by nicotinamide (NAM) supplementation maintains cochlear mitochondrial homeostasis and prevents neuroexcitatory toxic injury in vitro and ex vivo, also significantly ameliorated NIHL in vivo. To tackle the limited drug delivery efficiency due to sophisticated anatomical barriers and unique clearance pathway in ear, personalized NAM-encapsulated porous gelatin methacryloyl (PGMA@NAM) are developed based on anatomy topography of murine temporal bone by micro-computed tomography and reconstruction of round window (RW) niche, realizing hydrogel in situ implantation completely, NAM sustained-release and long-term auditory preservation in mice. This study strongly supports personalized PGMA@NAM as NIHL protection drug with effective inner ear delivery, providing new inspiration for drug-based treatment of NIHL.

Chemerin/CMKLR1 pathway exacerbates cisplatin-induced spiral ganglion neuron injury

This study investigated whether chemerin/chemokine-like receptor 1 (CMKLR1) pathway participate in cisplatin-induced spiral ganglion neuron (SGN) damage. Middle cochlear turn was collected from C57BL/6 mice and the SGNs were cultured. Cisplatin, 2-(anaphthoyl) ethyltrimethylammonium iodide (α-NETA), or recombinant mouse chemerin was added into the medium for the treatment. Relative mRNA and protein expression was determined by RT-PCR, ELISA and Western blot, respectively. In cultured mouse cochlear SGNs, the treatment of cisplatin enhanced the secretion of chemerin and CMKLR1. Recombinant chemerin promoted but α-NETA inhibited chemerin/CMKLR1 pathway in cisplatin stimulated SGNs. Cisplatin-induced apoptosis and inflammation response in SGNs were enhanced by recombinant chemerin while inhibited by α-NETA. Recombinant chemerin promoted but α-NETA inhibited NF-κB signal in cisplatin stimulated SGNs. In conclusion, chemerin/CMKLR1 pathway regulated apoptosis and inflammation response in cisplatin-induced SGN injury through NF-κB signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00205-0.

DJ-1 Protects Auditory Cells from Cisplatin-induced Ototoxicity via Regulating Apoptosis and Autophagy

AIMS

DJ-1, a multifunctional protein encoded by the Park7 gene, is tightly related to mitochondrial dysfunction, oxidative stress, protein aggregation, and autophagy regulation. The current study was designed to investigate whether DJ-1 is expressed in auditory cells and, if so, to explore the possible correlation between DJ-1 and cisplatin-induced ototoxicity in this type of cells.

METHODS

The location and dynamic expression of DJ-1 in mouse cochlea hair cells (HCs) and House Ear Institute-Organ of Corti 1 (HEI-OC1 cells) were detected by immunofluorescence, real-time PCR, and western blot. The apoptosis of auditory cells was assessed by TUNEL staining and flow cytometry. The levels of ROS were evaluated by MitoSox red staining. The expression of protein cleaved caspase-9, cleaved caspase-3, and LC3B was examined by immunofluorescence and western blot. The expressions of certain key factors relevant to apoptosis (Bcl-2 and Bax) and autophagy (Beclin1, p-JNK, and p-c-Jun) were determined by western blot. The dynamic alterations of those factors in response to DJ-1 knockdown in HEI-OC1 cells (DJ-1-KD) were measured by western blotting and MitoSox red staining.

RESULTS

The expression of DJ-1 was clearly shown in both HCs and HEI-OC1 cells and cisplatin led to the reduction of DJ-1 expression in a concentration and time-dependent manner. Meanwhile, cisplatin-induced apoptotic process was implemented by promoting reactive oxygen species (ROS) production and activating the mitochondrial pathway. Furthermore, DJ-1 explicitly participated in cisplatin-trigged cell damage by regulating autophagy.

CONCLUSIONS

Findings from this work clearly reveal, for the first time, that DJ-1 is expressed in the cochlea. Of particular importance, DJ-1 exerts its protective action against cisplatin-elicited injury on auditory cells via regulating apoptosis and autophagy, which provides a new strategy for the prevention of cisplatin-induced ototoxicity.

Approaches to Mitigate Mitochondrial Dysfunction in Sensorineural Hearing Loss

Mitochondria are highly dynamic multifaceted organelles with various functions including cellular energy metabolism, reactive oxygen species (ROS) generation, calcium homeostasis, and apoptosis. Because of these diverse functions, mitochondria are key regulators of cell survival and death, and their dysfunction is implicated in numerous diseases, particularly neurodegenerative disorders such as Alzheimer's Disease, Parkinson's Disease, and Huntington's Disease. One of the most common neurodegenerative disorders is sensorineural hearing loss (SNHL). SNHL primarily originates from the degenerative changes in the cochlea, which is the auditory portion of the inner ear. Many cochlear cells contain an abundance of mitochondria and are metabolically highly active, rendering them susceptible to mitochondrial dysfunction. Indeed, the causal role of mitochondrial dysfunction in SNHL progression is well established, and therefore, targeted for treatment. In this review, we aim to compile the emerging findings in the literature indicating the role of mitochondrial dysfunction in the progression of sensorineural hearing loss and highlight potential therapeutics targeting mitochondrial dysfunction for hearing loss treatment.

Mitochondrial autophagy: molecular mechanisms and implications for cardiovascular disease

Mitochondria are highly dynamic organelles that participate in ATP generation and involve calcium homeostasis, oxidative stress response, and apoptosis. Dysfunctional or damaged mitochondria could cause serious consequences even lead to cell death. Therefore, maintaining the homeostasis of mitochondria is critical for cellular functions. Mitophagy is a process of selectively degrading damaged mitochondria under mitochondrial toxicity conditions, which plays an essential role in mitochondrial quality control. The abnormal mitophagy that aggravates mitochondrial dysfunction is closely related to the pathogenesis of many diseases. As the myocardium is a highly oxidative metabolic tissue, mitochondria play a central role in maintaining optimal performance of the heart. Dysfunctional mitochondria accumulation is involved in the pathophysiology of cardiovascular diseases, such as myocardial infarction, cardiomyopathy and heart failure. This review discusses the most recent progress on mitophagy and its role in cardiovascular disease.

Regulation of ACSL4-Catalyzed Lipid Peroxidation Process Resists Cisplatin Ototoxicity

Cisplatin-induced ototoxicity is one of the common side effects during its treatment and there are no effective measures to prevent it. Our study aimed to investigate the effect of ACSL4-catalyzed lipid peroxidation on cisplatin-induced hearing loss and its possible protective mechanisms. We used a variety of cisplatin ototoxicity models, including HEI-OC1 cell line, cochlear explants, and ET4 GFP+ zebrafish. After measuring the experimental concentrations of cisplatin by CCK8 assay and immunofluorescence, respectively, we examined the levels of lipid peroxidation by MDA content, 4-HNE content, and C11-BODIPY (581/591) probe. Then, we used two ferroptosis inhibitors, FER-1, and Vit-E to protect hair cells. We found that cisplatin significantly increased the levels of lipid peroxidation and that this process can be resisted by the ferroptosis inhibitors. Afterwards, we performed metabolomic assays on the cisplatin-treated hair cells. The metabolite levels were significantly altered in the experimental group compared to the control group, and the highest degree of change was observed in the glutathione metabolic pathway and the arachidonic acid metabolic pathway. Therefore, we screened the key enzymes on the arachidonic acid metabolic pathway in the hair cells after cisplatin treatment and found that ACSL4 had the greatest regulatory value. Further, we reduced the level of lipid peroxide in hair cells by specifically inhibiting the expression of ACSL4, which protected hair cells from cisplatin damage at source. In conclusion, the lipid peroxidation process regulated by ACSL4 may be an important factor contributing to the sensitivity of hair cells to cisplatin. Inhibition of ACSL4 expression may be an effective preventive measure against cisplatin ototoxicity.

Mitochondria and Their Relationship with Common Genetic Abnormalities in Hematologic Malignancies

Hematologic malignancies are known to be associated with numerous cytogenetic and molecular genetic changes. In addition to morphology, immunophenotype, cytochemistry and clinical characteristics, these genetic alterations are typically required to diagnose myeloid, lymphoid, and plasma cell neoplasms. According to the current World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissues, numerous genetic changes are highlighted, often defining a distinct subtype of a disease, or providing prognostic information. This review highlights how these molecular changes can alter mitochondrial bioenergetics, cell death pathways, mitochondrial dynamics and potentially be related to mitochondrial genetic changes. A better understanding of these processes emphasizes potential novel therapies.