Effect of tibolone and raloxifene on serum markers of apoptosis in postmenopausal women

Repurposing of Tibolone in Alzheimer's Disease

Alzheimer's disease (AD) is a debilitating neurodegenerative disease characterised by the accumulation of amyloid-beta and tau in the brain, leading to the progressive loss of memory and cognition. The causes of its pathogenesis are still not fully understood, but some risk factors, such as age, genetics, and hormones, may play a crucial role. Studies show that postmenopausal women have a higher risk of developing AD, possibly due to the decrease in hormone levels, especially oestrogen, which may be directly related to a reduction in the activity of oestrogen receptors, especially beta (ERβ), which favours a more hostile cellular environment, leading to mitochondrial dysfunction, mainly affecting key processes related to transport, metabolism, and oxidative phosphorylation. Given the influence of hormones on biological processes at the mitochondrial level, hormone therapies are of clinical interest to reduce the risk or delay the onset of symptoms associated with AD. One drug with such potential is tibolone, which is used in clinics to treat menopause-related symptoms. It can reduce amyloid burden and have benefits on mitochondrial integrity and dynamics. Many of its protective effects are mediated through steroid receptors and may also be related to neuroglobin, whose elevated levels have been shown to protect against neurological diseases. Its importance has increased exponentially due to its implication in the pathogenesis of AD. In this review, we discuss recent advances in tibolone, focusing on its mitochondrial-protective effects, and highlight how valuable this compound could be as a therapeutic alternative to mitigate the molecular pathways characteristic of AD.

Network pharmacology identifies IL6 as an important hub and target of tibolone for drug repurposing in traumatic brain injury

Traumatic brain injury (TBI) is characterized by a complex network of signals mediating inflammatory, proliferative and apoptotic processes during its acute and chronic phases. Current therapies mitigate damage and are mainly for palliative care and there are currently no effective therapies for secondary damage. This suggests a need to discover a compound with a greater spectrum of action that can control various pathological aspects of TBI. Here we used a network pharmacology approach to explore the benefits of tibolone, an estrogen and androgen receptor agonist with broader actions in cells, as a possible repurposing drug for TBI therapy. Using different databases we retrieved the targets significantly associated to TBI and tibolone, obtaining 2700 and 652, respectively. The top 10 GO enriched terms were mostly related to cell proliferation, apoptosis and inflammation. Following protein-protein functional analysis, the top connected proteins were related to kinase activity (MAPK1/14/3, AKT1 PIK3R1), apoptosis (TP53, CASP3), growth factors (EGFR), estrogen signalling (ESR1) and inflammation (IL6, TNF), with IL6 as an important signalling hub belonging to the top GO categories. Thus, we identified IL6 as a cellular node which we then validated using molecular mechanics-generalized born surface area (MMGBSA) and docking to explore which tibolone metabolite might interact with this protein. Both 3α and 3β-OH tibolone seemed to bind better to IL6 at important sites responsible for its binding to IL6R. In conclusion, our study demonstrates key hubs involved in TBI pathology which indicates IL6 as a target molecule of tibolone as drug repurposing for TBI therapy.