Modern In Vitro Techniques for Modeling Hearing Loss.

Sensorineural hearing loss (SNHL) is a prevalent and growing global health concern, especially within operational medicine, with limited therapeutic options available. This review article explores the emerging field of in vitro otic organoids as a promising platform for modeling hearing loss and developing novel therapeutic strategies. SNHL primarily results from the irreversible loss or dysfunction of cochlear mechanosensory hair cells (HCs) and spiral ganglion neurons (SGNs), emphasizing the need for innovative solutions. Current interventions offer symptomatic relief but do not address the root causes. Otic organoids, three-dimensional multicellular constructs that mimic the inner ear's architecture, have shown immense potential in several critical areas. They enable the testing of gene therapies, drug discovery for sensory cell regeneration, and the study of inner ear development and pathology. Unlike traditional animal models, otic organoids closely replicate human inner ear pathophysiology, making them invaluable for translational research. This review discusses methodological advances in otic organoid generation, emphasizing the use of human pluripotent stem cells (hPSCs) to replicate inner ear development. Cellular and molecular characterization efforts have identified key markers and pathways essential for otic organoid development, shedding light on their potential in modeling inner ear disorders. Technological innovations, such as 3D bioprinting and microfluidics, have further enhanced the fidelity of these models. Despite challenges and limitations, including the need for standardized protocols and ethical considerations, otic organoids offer a transformative approach to understanding and treating auditory dysfunctions. As this field matures, it holds the potential to revolutionize the treatment landscape for hearing and balance disorders, moving us closer to personalized medicine for inner ear conditions.

Sudden Death in Diabetic Ketoacidosis Complicated by Sickle Cell Trait.

ABSTRACT: In a sudden death investigation of a service member with sickle cell trait (SCT), evidence of sickle cell crisis further complicated by coexisting, undiagnosed diabetic ketoacidosis called into question the synergistic effects of diabetic ketoacidosis on red blood cell sickling. Sickle cell trait affects more than 4 million people in the United States (US) with the highest prevalence in non-Hispanic Blacks (7%-9%; Mil Med 2017;182(3):e1819-e1824). The heterozygous state of sickled hemoglobin was previously considered a benign condition causing sickling during hypoxic, high-stress conditions such as exercise and high altitude ( Am Assoc Clin Chem 2017). However, research within the last decade shows evidence of sudden death among SCT patients ( J Forensic Sci 2011;56(5):1352-1360). It has been shown that the presence of sickled hemoglobin artificially lowers levels of hemoglobin A1c making it a less effective biomarker for red blood cell glycosylation over time in sickle cell patients ( JAMA 2017;317(5):507-515). The limited scope of medical understanding of the effects of SCT in combination with other comorbidities requires further investigation and better diagnostic criteria. The uniqueness of the US Military and its screening program for sickle cell disease (SCD) and SCT allows for more detection. Since May 2006, newborn screening for SCD/SCT has been a national requirement; however, anyone older than 14 years may not know their SCD/SCT status ( Semin Perinatol 2010;34(2):134-44). The previous absence of such national screening makes it more challenging to identify SCT and SCD patients even within high-risk populations. Furthermore, patients may not know or understand the results of their SCD/SCT status testing. International standards for the autopsy of decedents with SCD and SCT exist ( R Coll Pathol 2017). Within the US, testing of vitreous electrolytes is a common practice in suspected natural death cases, but a review of the US literature did not demonstrate any autopsy standards or recommendations for persons with SCT or high-risk persons for sickling pathologies. The identification of a new diagnosis of type 2 diabetes mellitus, as the cause of death, is not uncommon; however, this case indicates that type 2 diabetes mellitus was not the sole contributing factor. It further illustrates that the US may be underestimating the impact of SCD and SCT as a cause of death, a contributing factor to death, and its synergistic effects with other pathologic processes. We propose a stringent literature review in conjunction with a review of international autopsy standards to develop national autopsy standards and possible SCT/SCD screening recommendations for high-risk persons at the time of autopsy.

Gamma Secretase Inhibition by BMS-906024 Enhances Efficacy of Paclitaxel in Lung Adenocarcinoma.

Notch signaling is aberrantly activated in approximately one third of non-small cell lung cancers (NSCLC). We characterized the interaction between BMS-906024, a clinically relevant Notch gamma secretase inhibitor, and front-line chemotherapy in preclinical models of NSCLC. Chemosensitivity assays were performed on 14 human NSCLC cell lines. There was significantly greater synergy between BMS-906024 and paclitaxel than BMS-906024 and cisplatin [mean combination index (CI) value, 0.54 and 0.85, respectively, P = 0.01]. On an extended panel of 31 NSCLC cell lines, 25 of which were adenocarcinoma, the synergy between BMS-906024 and paclitaxel was significantly greater in KRAS- and BRAF-wildtype than KRAS- or BRAF-mutant cells (mean CI, 0.43 vs. 0.90, respectively; P = 0.003). Paclitaxel-induced Notch1 activation was associated with synergy between BMS-906024 and paclitaxel in the KRAS- or BRAF-mutant group. Knockdown of mutant KRAS increased the synergy between BMS-906024 and paclitaxel in heterozygous KRAS-mutant cell lines. Among KRAS- or BRAF-mutant NSCLC, there was a significant correlation between synergy and mutant or null TP53 status, as well as between synergy and a low H2O2 pathway signature. Exogenous overexpression of activated Notch1 or Notch3 had no effect on the enhanced sensitivity of NSCLC to paclitaxel by BMS-906024. In vivo studies with cell line- and patient-derived lung adenocarcinoma xenografts confirmed enhanced antitumor activity for BMS-906024 plus paclitaxel versus either drug alone via decreased cell proliferation and increased apoptosis. These results show that BMS-906024 sensitizes NSCLC to paclitaxel and that wild-type KRAS and BRAF status may predict better patient response to the combination therapy. Mol Cancer Ther; 16(12); 2759-69. ©2017 AACR.

SOX9 is targeted for proteasomal degradation by the E3 ligase FBW7 in response to DNA damage.

SOX9 encodes a transcription factor that governs cell fate specification throughout development and tissue homeostasis. Elevated SOX9 is implicated in the genesis and progression of human tumors by increasing cell proliferation and epithelial-mesenchymal transition. We found that in response to UV irradiation or genotoxic chemotherapeutics, SOX9 is actively degraded in various cancer types and in normal epithelial cells, through a pathway independent of p53, ATM, ATR and DNA-PK. SOX9 is phosphorylated by GSK3ß, facilitating the binding of SOX9 to the F-box protein FBW7α, an E3 ligase that functions in the DNA damage response pathway. The binding of FBW7α to the SOX9 K2 domain at T236-T240 targets SOX9 for subsequent ubiquitination and proteasomal destruction. Exogenous overexpression of SOX9 after genotoxic stress increases cell survival. Our findings reveal a novel regulatory mechanism for SOX9 stability and uncover a unique function of SOX9 in the cellular response to DNA damage. This new mechanism underlying a FBW7-SOX9 axis in cancer could have implications in therapy resistance.