Suberoylanilide Hydroxamic Acid (SAHA) Is a Driver Molecule of Neuroplasticity: Implication for Neurological Diseases

Identification of a histone deacetylase inhibitor as a therapeutic candidate for congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS), a rare genetic disease caused by heterozygous PHOX2B mutations, is characterized by life-threatening breathing deficiencies. PHOX2B is a transcription factor required for the specification of the autonomic nervous system, which contains, in particular, brainstem respiratory centers. In CCHS, PHOX2B mutations lead to cytoplasmic PHOX2B protein aggregations, thus compromising its transcriptional capability. Currently, the only available treatment for CCHS is assisted mechanical ventilation. Therefore, identifying molecules with alleviating effects on CCHS-related breathing impairments is of primary importance. A transcriptomic analysis of cells transfected with different PHOX2B constructs was used to identify compounds of interest with the CMap tool. Using fluorescence microscopy and luciferase assay, the selected molecules were further tested in vitro for their ability to restore the nuclear location and function of PHOX2B. Finally, an electrophysiological approach was used to investigate ex vivo the effects of the most promising molecule on respiratory activities of PHOX2B-mutant mouse isolated brainstem. The histone deacetylase inhibitor SAHA was found to have low toxicity in vitro, to restore the proper location and function of PHOX2B protein, and to improve respiratory rhythm-related parameters ex vivo. Thus, our results identify SAHA as a promising agent to treat CCHS-associated breathing deficiencies.

Targeting epigenetic dysregulation in autism spectrum disorders

Autism spectrum disorders (ASD) comprise a range of neurodevelopmental pathologies characterized by deficits in social interaction and repetitive behaviors, collectively affecting almost 1% of the worldwide population. Deciphering the etiology of ASD has proven challenging due to the intricate interplay of genetic and environmental factors and the variety of molecular pathways affected. Epigenomic alterations have emerged as key players in ASD etiology. Their research has led to the identification of biomarkers for diagnosis and pinpointed specific gene targets for therapeutic interventions. This review examines the role of epigenetic alterations, resulting from both genetic and environmental influences, as a central causative factor in ASD, delving into its contribution to pathogenesis and treatment strategies.

Role of histone deacetylases and their inhibitors in neurological diseases

Histone deacetylases (HDACs) are zinc-dependent deacetylases that remove acetyl groups from lysine residues of histones or form protein complexes with other proteins for transcriptional repression, changing chromatin structure tightness, and inhibiting gene expression. Recent in vivo and in vitro studies have amply demonstrated the critical role of HDACs in the cell biology of the nervous system during both physiological and pathological processes and have provided new insights into the conduct of research on neurological disease targets. In addition, in vitro and in vivo studies on HDAC inhibitors show promise for the treatment of various diseases. This review summarizes the regulatory mechanisms of HDAC and the important role of its downstream targets in nervous system diseases, and summarizes the therapeutic mechanisms and efficacy of HDAC inhibitors in various nervous system diseases. Additionally, the current pharmacological situation, problems, and developmental prospects of HDAC inhibitors are described. A better understanding of the pathogenic mechanisms of HDACs in the nervous system may reveal new targets for therapeutic interventions in diseases and help to relieve healthcare pressure through preventive measures.

Preliminary study on the mechanism of SAHA in the treatment of refractory epilepsy induced by GABRG2(F343L) mutation

Mutations in the γ-amino butyric acid type A (GABAA) receptor γ2 subunit gene, GABRG2, have been associated with refractory epilepsy. Increasing evidence indicates that suberoylanilide hydroxamic acid (SAHA), a broad-spectrum histone acetyltransferases (HDACs) inhibitor, can inhibit seizure onset. However, the mechanisms involved remains unknown. The present study aimed to explore the anti-epileptic effect and underlying mechanisms of SAHA in the treatment of refractory epilepsy induced by GABRG2 mutation. In the zebrafish line expressing human mutant GABRG2(F343L), Tg(hGABRG2F343L), SAHA was found to reduce seizure onset, swimming activity, and neuronal activity. In both Tg(hGABRG2F343L) zebrafish and HEK293T cells transfected with GABAA receptor subunits, SAHA could improve the pan-acetylation level and reduce the expression of HDAC1/10. The decreased expressions of GABAA receptor subunits could be rescued by SAHA treatment both in vivo and in vitro, which might be the result of increased gene transcription and protein trafficking. The up-regulated acetylation of histone H3 and H4 as well as Bip expression might be involved in the process. Taken together, our data proved that both histone and non-histone acetylation might contribute to the anti-epileptic effect of SAHA in refractory epilepsy caused by GABRG2(F343L) mutation, demonstrating SAHA as a promising therapeutic agent for refractory epilepsy.

Targeting senescent cells to reshape the tumor microenvironment and improve anticancer efficacy

Cancer is daunting pathology with remarkable breadth and scope, spanning genetics, epigenetics, proteomics, metalobomics and cell biology. Cellular senescence represents a stress-induced and essentially irreversible cell fate associated with aging and various age-related diseases, including malignancies. Senescent cells are characterized of morphologic alterations and metabolic reprogramming, and develop a highly active secretome termed as the senescence-associated secretory phenotype (SASP). Since the first discovery, senescence has been understood as an important barrier to tumor progression, as its induction in pre-neoplastic cells limits carcinogenesis. Paradoxically, senescent cells arising in the tumor microenvironment (TME) contribute to tumor progression, including augmented therapeutic resistance. In this article, we define typical forms of senescent cells commonly observed within the TME and how senescent cells functionally remodel their surrounding niche, affect immune responses and promote cancer evolution. Furthermore, we highlight the recently emerging pipelines of senotherapies particularly senolytics, which can selectively deplete senescent cells from affected organs in vivo and impede tumor progression by restoring therapeutic responses and securing anticancer efficacies. Together, co-targeting cancer cells and their normal but senescent counterparts in the TME holds the potential to achieve increased therapeutic benefits and restrained disease relapse in future clinical oncology.