Epigenetic mechanisms regulate sex-specific bias in disease manifestations.

Sex presents a vital determinant of a person's physiology, anatomy, and development. Recent clinical studies indicate that sex is also involved in the differential manifestation of various diseases, affecting both clinical outcome as well as response to therapy. Genetic and epigenetic changes are implicated in sex bias and regulate disease onset, including the inactivation of the X chromosome as well as sex chromosome aneuploidy. The differential expression of X-linked genes, along with the presence of sex-specific hormones, exhibits a significant impact on immune system function. Several studies have revealed differences between the two sexes in response to infections, including respiratory diseases and COVID-19 infection, autoimmune disorders, liver fibrosis, neuropsychiatric diseases, and cancer susceptibility, which can be explained by sex-biased immune responses. In the present review, we explore the input of genetic and epigenetic interplay in the sex bias underlying disease manifestation and discuss their effects along with sex hormones on disease development and progression, aiming to reveal potential new therapeutic targets. KEY MESSAGES: Sex is involved in the differential manifestation of various diseases. Epigenetic modifications influence X-linked gene expression, affecting immune response to infections, including COVID-19. Epigenetic mechanisms are responsible for the sex bias observed in several respiratory and autoimmune disorders, liver fibrosis, neuropsychiatric diseases, and cancer.

Laying the groundwork for the Biobank of Rare Malignant Neoplasms at the service of the Hellenic Network of Precision Medicine on Cancer.

Biobanks constitute an integral part of precision medicine. They provide a repository of biospecimens that may be used to elucidate the pathophysiology, support diagnoses, and guide the treatment of diseases. The pilot biobank of rare malignant neoplasms has been established in the context of the Hellenic Network of Precision Medicine on Cancer and aims to enhance future clinical and/or research studies in Greece by collecting, processing, and storing rare malignant neoplasm samples with associated data. The biobank currently comprises 553 samples; 384 samples of hematopoietic and lymphoid tissue malignancies, 72 samples of pediatric brain tumors and 97 samples of malignant skin neoplasms. In this article, sample collections and their individual significance in clinical research are described in detail along with computational methods developed specifically for this project. A concise review of the Greek biobanking landscape is also delineated, in addition to recommended technologies, methodologies and protocols that were integrated during the creation of the biobank. This project is expected to re­enforce current clinical and research studies, introduce advances in clinical and genetic research and potentially aid in future targeted drug discovery. It is our belief that the future of medical research is entwined with accessible, effective, and ethical biobanking and that our project will facilitate research planning in the '­omic' era by contributing high­quality samples along with their associated data.

Epigenetic mechanisms regulating COVID-19 infection.

Coronavirus disease 2019 (COVID-2019) outbreak originating in December 2019 in Wuhan, China has emerged as a global threat to human health. The highly contagious SARS-CoV-2 infection and transmission presents a diversity of human host and increased disease risk with advancing age, highlighting the importance of in-depth understanding of its biological properties. Structural analyses have elucidated hot spots in viral binding domains, mutations, and specific proteins in the host such as the receptor angiotensin-converting enzyme 2 (ACE2) and the transmembrane protease serine 2 (TMPRSS2) to be implicated in cell entry and viral infectivity. Furthermore, epigenetic changes that regulate chromatin structure have shown a major impact in genome stabilization and maintenance of cellular homoeostasis and they have been implicated in the pathophysiology of the virus infection. Epigenetic research has revealed that global DNA methylation along with ACE2 gene methylation and post-translational histone modifications may drive differences in host tissue-, biological age- and sex-biased patterns of viral infection. Moreover, modulation of the host cells epigenetic landscape following infection represents a molecular tool used by viruses to antagonize cellular signalling as well as sensing components that regulate the induction of the host innate immune and antiviral defence programmes in order to enhance viral replication and infection efficiency. In this review, we provide an update of the main research findings at the interface of epigenetics and coronavirus infection. In particular, we highlight the epigenetic factors that interfere with viral replication and infection and may contribute to COVID-19 susceptibility, offering new ways of thinking in respect to host viral response.