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Age-related hearing loss in humans has been associated with cognitive decline, though the underlying mechanisms remain unknown. We investigated the long-term effects of hearing loss on attention, impulse control, social interaction, and neural activity within medial prefrontal cortex (mPFC) subregions. Hearing loss was induced in adult rats via intracochlear neomycin injection (n = 13), with non-operated rats as controls (n = 10). Rats were tested for motor activity (open field), coordination (Rotarod), and social interaction (including ultrasonic vocalization, USV) before surgery and at weeks 1, 2, 4, 8, 16, and 24 post-surgery. From week 8 on, rats were trained in the five-choice serial reaction time task (5-CSRTT) to assess visuospatial attention and impulse control. Finally, oscillatory neuronal activity in mPFC subregions was recorded with multielectrode arrays during anesthesia, followed by immunohistological staining for NeuN + and Parvalbumin + cells. Deafened rats were more active than controls, whereas social interaction and USV were temporarily reduced. They also had difficulties to learn the concept of the 5-CSRTT paradigm and made more incorrect responses. Electrophysiology showed decreased power in theta, alpha, and beta frequency, and enhanced high gamma band in the mPFC in deafened rats, which was most pronounced in the cingulate subregion (Cg1). The number of NeuN + and Parvalbumin + cells, however, did not differ between groups. The behavioral deficits together with the altered neuronal activity found in the Cg1 subregion of the mPFC in adult deafened rats may be used as an endophenotype to elucidate the mechanisms behind the cognitive decline seen in older patients with hearing loss., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

CpG islands near promoters are normally unmethylated despite being surrounded by densely methylated regions. Aberrant hypermethylation of these CpG islands has been associated with the development of various human diseases. Although local genetic elements have been speculated to play a role in protecting promoters from methylation, only a limited number of methylation barriers have been identified. In this study, we conducted an integrated computational and experimental investigation of colorectal cancer methylomes. Our study revealed 610 genes with disrupted methylation barriers. Genomic sequences of these barriers shared a common 41-bp sequence motif (MB-41) that displayed homology to the chicken HS4 methylation barrier. Using the CDKN2A (P16) tumor suppressor gene promoter, we validated the protective function of MB-41 and showed that loss of such protection led to aberrant hypermethylation. Our findings highlight a novel sequence signature of cis-acting methylation barriers in the human genome that safeguard promoters from silencing., (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Background: In children, hearing loss has been associated with hyperactivity, disturbed social interaction, and risk of cognitive disturbances. Mechanistic explanations of these relations sometimes involve language. To investigate the effect of hearing loss on behavioral deficits in the absence of language, we tested the impact of hearing loss in juvenile rats on motor, social, and cognitive behavior and on physiology of prefrontal cortex., Methods: Hearing loss was induced in juvenile (postnatal day 14) male Sprague-Dawley rats by intracochlear injection of neomycin under general anesthesia. Sham-operated and non-operated hearing rats served as controls. One week after surgery auditory brainstem response (ABR) measurements verified hearing loss or intact hearing in sham-operated and non-operated controls. All rats were then tested for locomotor activity (open field), coordination (Rotarod), and for social interaction during development in weeks 1, 2, 4, 8, 16, and 24 after surgery. From week 8 on, rats were trained and tested for spatial learning and memory (4-arm baited 8-arm radial maze test). In a final setting, neuronal activity was recorded in the medial prefrontal cortex (mPFC)., Results: In the open field deafened rats moved faster and covered more distance than sham-operated and non-operated controls from week 8 on (both p < 0.05). Deafened rats showed significantly more play fighting during development (p < 0.05), whereas other aspects of social interaction, such as following, were not affected. Learning of the radial maze test was not impaired in deafened rats (p > 0.05), but rats used less next-arm entries than other groups indicating impaired concept learning (p < 0.05). In the mPFC neuronal firing rate was reduced and enhanced irregular firing was observed. Moreover, oscillatory activity was altered, both within the mPFC and in coherence of mPFC with the somatosensory cortex (p < 0.05)., Conclusions: Hearing loss in juvenile rats leads to hyperactive behavior and pronounced play-fighting during development, suggesting a causal relationship between hearing loss and cognitive development. Altered neuronal activities in the mPFC after hearing loss support such effects on neuronal networks outside the central auditory system. This animal model provides evidence of developmental consequences of juvenile hearing loss on prefrontal cortex in absence of language as potential confounding factor., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Background: Inhibition of cyclin-dependent kinase 9 (CDK9), a novel epigenetic target in cancer, can reactivate epigenetically silenced genes in cancer by dephosphorylating the SWI/SNF chromatin remodeler BRG1. Here, we characterized the anti-tumor efficacy of MC180295, a newly developed CDK9 inhibitor., Methods: In this study, we explored the pharmacokinetics of MC180295 in mice and rats, and tested the anti-tumor efficacy of MC180295, and its enantiomers, in multiple cancer cell lines and mouse models. We also combined CDK9 inhibition with a DNA methyltransferase (DNMT) inhibitor, decitabine, in multiple mouse models, and tested MC180295 dependence on T cells. Drug toxicity was measured by checking body weights and complete blood counts., Results: MC180295 had high specificity for CDK9 and high potency against multiple neoplastic cell lines (median IC50 of 171 nM in 46 cell lines representing 6 different malignancies), with the highest potency seen in AML cell lines derived from patients with MLL translocations. MC180295 is a racemic mixture of two enantiomers, MC180379 and MC180380, with MC180380 showing higher potency in a live-cell epigenetic assay. Both MC180295 and MC180380 showed efficacy in in vivo AML and colon cancer xenograft models, and significant synergy with decitabine in both cancer models. Lastly, we found that CDK9 inhibition-mediated anti-tumoral effects were partially dependent on CD8 + T cells in vivo, indicating a significant immune component to the response., Conclusions: MC180380, an inhibitor of cyclin-dependent kinase 9 (CDK9), is an efficacious anti-cancer agent worth advancing further toward clinical use., (© 2023. The Author(s).)

The intestinal microbiota is an important environmental factor implicated in CRC development. Intriguingly, modulation of DNA methylation by gut microbiota has been reported in preclinical models, although the relationship between tumor-infiltrating bacteria and CIMP status is currently unexplored. In this study, we investigated tumor-associated bacteria in 203 CRC tumor cases and validated the findings using The Cancer Genome Atlas datasets. We assessed the abundance of Bacteroides fragilis , Escherichia coli , Fusobacterium nucleatum , and Klebsiella pneumoniae through qPCR analysis and observed enrichment of all four bacterial species in CRC samples. Notably, except for E. coli , all exhibited significant enrichment in cases of CIMP. This enrichment was primarily driven by a subset of cases distinguished by high levels of these bacteria, which we labeled as "Superhigh". The bacterial Superhigh status showed a significant association with CIMP (odds ratio 3.1, p-value = 0.013) and with MLH1 methylation (odds ratio 4.2, p-value = 0.0025). In TCGA CRC cases (393 tumor and 45 adj. normal), bacterial taxa information was extracted from non-human whole exome sequencing reads, and the bacterial Superhigh status was similarly associated with CIMP (odds ratio 2.9, p  < 0.001) and MLH1 methylation (odds ratio 3.5, p  < 0.001). Finally, 16S ribosomal RNA gene sequencing revealed high enrichment of Bergeyella spp . C. concisus , and F. canifelinum in CIMP-Positive tumor cases. Our findings highlight that specific bacterial taxa may influence DNA methylation, particularly in CpG islands, and contribute to the development and progression of CIMP in colorectal cancer.

Background: DNA methylation analysis might identify prognostic CpG sites in CHOP-treated dogs with multicentric high-grade B-cell lymphoma (MHGL) with heterogenous prognosis., Objective: To identify prognostic CpG sites of MHGL through genome-wide DNA methylation analysis with pyrosequencing validation., Animals: Test group: 24 dogs. Validation group: 100 dogs. All client-owned dogs were diagnosed with MHGL and treated with CHOP chemotherapy., Methods: Cohort study. DNA was extracted from lymph node samples obtained via FNA. Genome-wide DNA methylation analysis using Digital Restriction Enzyme Analysis of Methylation (DREAM) was performed on the test group to identify differentially methylated CpG sites (DMCs). Bisulfite pyrosequencing was used to measure methylation status of candidate DMCs in the validation group. Median survival times (MST) were analyzed using Kaplan-Meier (log-rank) product limit method., Results: DREAM analyzed 101 576 CpG sites. Hierarchical clustering of 16 262 CpG sites in test group identified group with better prognosis (MST = 55-477 days vs 10-301 days, P = .007). Volcano plot identified 1371 differentially methylated CpG sites (DMCs). DMC near the genes of FAM213A (DMC-F) and PHLPP1 (DMC-P) were selected as candidates. Bisulfite-pyrosequencing performed on validation group showed group with methylation level of DMC-F < 40% had favorable prognosis (MST = 11-1072 days vs 8-1792 days, P = .01), whereas group with the methylation level combination of DMC-F < 40% plus DMC-P < 10% had excellent prognosis (MST = 18-1072 days vs 8-1792 days, P = .009)., Conclusion and Clinical Importance: Methylation status of prognostic CpG sites delineate canine MGHL cases with longer MST, providing owners with information on expectations of potential improved treatment outcomes., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)