Sirtuins 1 and 2 in the Acute Period After Photothrombotic Stroke: Expression, Localization and Involvement in Apoptosis

Fn14 Controls the SIRT2-Mediated Deacetylation of Slug to Inhibit the Metastasis of Epithelial Ovarian Cancer

Metastatic spread of cancer is the leading cause of death in patients with epithelial ovarian cancer (EOC), and elucidation of the molecular mechanisms underlying this process is a major focus of cancer research. Fibroblast growth factor-inducible 14 (Fn14) has been shown to regulate wound repair, inflammation, angiogenesis, and chemoresistance, but its functional role in metastasis in EOC is still unknown. Here it is reported that Fn14 is identified as a cancer metastasis suppressor that inhibits the migratory and invasive potential of EOC cells by down-regulating epithelial-mesenchymal transition (EMT). Mechanistically, it is identified that Fn14 promotes acetylation-dependent protein degradation of Slug, a key transcriptional factor associated with EMT. The deacetylase Sirtuin 2 (SIRT2) has been reported to be involved in the deacetylation of Slug protein to stabilize it and then prevent its degradation in the nucleus. The results showed that Fn14 alters the subcellular localization of (SIRT2) by interacting with SIRT2, leading to reduced SIRT2 shuttling into the nucleus and subsequently promoting the acetylated degradation of Slug. Collectively, the work has demonstrated for the first time that Fn14 inhibits EOC metastasis by regulating SIRT2-mediated Slug deacetylation, providing a new perspective and method for the development of future novel therapeutic strategies for the treatment of EOC metastasis.

Role of histone deacetylases and sirtuins in the ischaemic stroke: a systematic review and meta-analysis of animal studies

BACKGROUND

Treatment of ischaemic stroke requires exploration of novel neuroprotective strategies owing to the constraints of thrombolytic therapy. Recent research implies that modulation of histone deacetylases (HDAC) or sirtuins (SIRT) could be beneficial in achieving this goal.

METHODS

This systematic review and meta-analysis evaluates the effectiveness of HDAC/SIRT enzyme modulation in treating acute ischaemic stroke. It includes relevant studies but excludes human and in vitro research and non-primary studies. An electronic search was conducted across databases PubMed, Web of Science and Scopus until 20 March 2025. The methodological quality was assessed using a modified SYRCLE risk of bias tool. Infarct volume and neurological responses were extracted as key outcomes, and a random-effects meta-analysis of infarct volume was conducted for studies directly targeting HDAC/SIRT enzymes.

RESULTS

A review of 71 studies involving over 1600 animals focused on ischaemic stroke treatments, predominantly using male rodents in a transient middle cerebral artery occlusion model. Most treatments were administered intraperitoneally, starting from the inception of ischaemia until 5 days afterwards. Non-selective HDAC inhibitors and SIRT1 modulators were targeted most frequently. The meta-analysis on infarct volume with 95% CI showed an overall effect estimate of -1.529 and suggested that non-selective HDAC inhibitors exhibit the most promise in reducing infarct size. Additionally, agonists of SIRT3/7, SIRT6, SIRT1 and HDAC1, along with inhibitors of SIRT5, HDAC6 and HDAC3, may play a significant role in the treatment of ischaemic stroke. Importantly, neuroprotective treatments have been found to be most effective in reducing infarct volume when administered within 24 hours following ischaemia.

DISCUSSION

This study highlights the most promising neuroprotective trials for ischaemic stroke by focusing on infarct volume as a key outcome. However, relying exclusively on infarct volume may not fully capture the effectiveness of these treatments.

Acetylation of p53 in the Cerebral Cortex after Photothrombotic Stroke

p53 expression and acetylation are crucial for the survival and death of neurons in penumbra. At the same time, the outcome of ischemia for penumbra cells depends largely on the histone acetylation status, but the effect of histone acetyltransferases and deacetylases on non-histone proteins like p53 is largely understudied. With combined in silico and in vitro approach, we have identified enzymes capable of acetylation/deacetylation, distribution, stability, and pro-apoptotic activity of p53 in ischemic penumbra in the course of post-stroke recovery, and also detected involved loci of acetylation in p53. The dynamic regulation of the acetylation of p53 at lysine 320 is controlled by acetyltransferase PCAF and histone deacetylases HDAC1 and HDAC6. The in silico simulation have made it possible to suggest the acetylation of p53 at lysine 320 acetylation may facilitate the shuttling of p53 between the nucleus and cytoplasm in penumbra neurons. Acetylation of p53 at lysine 320 is more preferable than acetylation at lysine 373 and probably promotes survival and repair of penumbra neurons after stroke. Strategies to increase p53 acetylation at lysine 320 via increasing PCAF activity, inhibiting HDAC1 or HDAC6, inhibiting p53, or a combination of these interventions may have therapeutic benefits for stroke recovery and would be promising for neuroprotective therapy of stroke.

Acetylation of c-Myc at Lysine 148 Protects Neurons After Ischemia

This study focuses on understanding the role of c-Myc, a cancer-associated transcription factor, in the penumbra following ischemic stroke. While its involvement in cell death and survival is recognized, its post-translational modifications, particularly acetylation, remain understudied in ischemia models. Investigating these modifications could have significant clinical implications for controlling c-Myc activity in the central nervous system. Although previous studies on c-Myc acetylation have been limited to non-neuronal cells, our research examines its expression in perifocal cells during stroke recovery to explore regulatory mechanisms via acetylation. We found that in peri-infarct neurons, c-Myc is upregulated with acetylation at K148 but not K323 during the acute phase of stroke, with SIRT2 deacetylase primarily affecting K148 acetylation. Molecular dynamics simulations suggest that lysine 148 plays a crucial role in stabilizing c-Myc spatial structure. Increased acetylation at K148 reduces c-Myc compaction, potentially limiting its nuclear penetration, promoting calpain-mediated cleavage, and decreasing nuclear localization. Additionally, cytoplasmic acetylation at K148 may alter c-Myc's interaction with unidentified proteins, potentially influencing its pro-apoptotic effects and promoting cytoplasmic accumulation. Targeting SIRT2 with selective inhibitors could be a promising avenue for future stroke therapy strategies.

SIRT1/SREBPs-mediated regulation of lipid metabolism

Sirtuins, also called silent information regulator 2, are enzymes that rely on nicotinamide adenine dinucleotide (NAD+) to function as histone deacetylases. Further investigation is warranted to explore the advantageous impacts of Sirtuin 1 (SIRT1), a constituent of the sirtuin group, on lipid metabolism, in addition to its well-researched involvement in extending lifespan. The regulation of gene expression has been extensively linked to SIRT1. Sterol regulatory element-binding protein (SREBP) is a substrate of SIRT1 that has attracted significant interest due to its role in multiple cellular processes including cell cycle regulation, DNA damage repair, and metabolic functions. Hence, the objective of this analysis was to investigate and elucidate the correlation between SIRT1 and SREBPs, as well as assess the contribution of SIRT1/SREBPs in mitigating lipid metabolism dysfunction. The objective of this research was to investigate whether SIRT1 and SREBPs could be utilized as viable targets for therapeutic intervention in managing complications associated with diabetes.

SIRT2 plays complex roles in neuroinflammation neuroimmunology-associated disorders

Neuroinflammation and neuroimmunology-associated disorders, including ischemic stroke and neurodegenerative disease, commonly cause severe neurologic function deficits, including bradypragia, hemiplegia, aphasia, and cognitive impairment, and the pathological mechanism is not completely clear. SIRT2, an NAD⁺-dependent deacetylase predominantly localized in the cytoplasm, was proven to play an important and paradoxical role in regulating ischemic stroke and neurodegenerative disease. This review summarizes the comprehensive mechanism of the crucial pathological functions of SIRT2 in apoptosis, necroptosis, autophagy, neuroinflammation, and immune response. Elaborating on the mechanism by which SIRT2 participates in neuroinflammation and neuroimmunology-associated disorders is beneficial to discover novel effective drugs for diseases, varying from vascular disorders to neurodegenerative diseases.

The roles of sirtuins in ferroptosis

Ferroptosis represents a novel non-apoptotic form of regulated cell death that is driven by iron-dependent lipid peroxidation and plays vital roles in various diseases including cardiovascular diseases, neurodegenerative disorders and cancers. Plenty of iron metabolism-related proteins, regulators of lipid peroxidation, and oxidative stress-related molecules are engaged in ferroptosis and can regulate this complex biological process. Sirtuins have broad functional significance and are targets of many drugs in the clinic. Recently, a growing number of studies have revealed that sirtuins can participate in the occurrence of ferroptosis by affecting many aspects such as redox balance, iron metabolism, and lipid metabolism. This article reviewed the studies on the roles of sirtuins in ferroptosis and the related molecular mechanisms, highlighting valuable targets for the prevention and treatment of ferroptosis-associated diseases.