The epigenetic effects of glucocorticoids, sex hormones and vitamin D as steroidal hormones in rheumatic musculoskeletal diseases.

Chronic rheumatological diseases are multifactorial conditions in which both the neuroendocrine hormone pathway, including cortisol, sex hormones and active vitamin D3 (calcitriol), all deriving from cholesterol, and the epigenetic modifications that they cause play an important role. In fact, epigenetics modulates the function of the DNA of immune cells, through three main mechanisms: DNA methylation, modifications to the histones that make up chromatin and production of non-coding RNAs (microRNA - miRNA). In this narrative review, the main data regarding the epigenetic modifications induced by cortisol, 17β-oestradiol, progesterone, testosterone and calcitriol on immune cells were collected, discussing how these can interfere in the predisposition and course of chronic rheumatological diseases (i.e. rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis). An ever-increasing number of miRNAs have been identified, which are produced by neuroendocrine hormones and can influence the inflammatory-fibrotic response at various levels. Concerning the involvements of the neuro-endocrine-immunology within the pathophysiology of rheumatic diseases, the epigenetic effects induced by steroid hormones must be taken into consideration to evaluate their impact on the progression of the single condition and even inside the single patient.