SIRT1 plays an important role in implantation and decidualization during mouse early pregnancy

Downregulation of Sirt3 contributes to β-cell dedifferentiation via FoxO1 in type 2 diabetic mellitus

AIMS

FoxO1 is an important factor in the β-cell differentiation in type 2 diabetes mellitus (T2DM). Sirt3 is found to be involved in FoxO1 function. This study investigated the role of Sirt3 in the β-cell dedifferentiation and its mechanism.

METHODS

Twelve-week-old db/db mice and INS1 cells transfected with Sirt3-specific short hairpin RNA (shSirt3) were used to evaluate the dedifferentiation of β-cell. Insulin levels were measured by enzyme linked immunosorbent assay. The proteins of Sirt3, T-FoxO1, Ac-FoxO1 and differentiation indexes such as NGN3, OCT4, MAFA were determined by western blot or immunofluorescence staining. The combination of Sirt3 and FoxO1 was determined by the co-immunoprecipitation assay. The transcriptional activity of FoxO1 was detected by dual luciferase reporter assay.

RESULTS

Both the in vivo and in vitro results showed that Sirt3 was decreased along with β-cell dedifferentiation and decreased function of insulin secretion under high glucose conditions. When Sirt3 was knocked down in INS1 cells, increased β-cell dedifferentiation and lowered insulin secretion were observed. This effect was closely related to the amount loss and the decreased deacetylation of FoxO1, which resulted in a reduction in transcriptional activity.

CONCLUSION

Downregulation of Sirt3 contributes to β-cell dedifferentiation in high glucose via FoxO1. Intervention of Sirt3 may be an effective approach to prevent β-cell failure in T2DM.

Molecular Mechanism of Resveratrol and Its Therapeutic Potential on Female Infertility

Resveratrol is a polyphenol present in various plant sources. Studies have reported numerous potential health benefits of resveratrol, exhibiting anti-aging, anti-inflammatory, anti-microbial, and anti-carcinogenic activity. Due to the reported effects, resveratrol is also being tested in reproductive disorders, including female infertility. Numerous cellular, animal, and even human studies were performed with a focus on the effect of resveratrol on female infertility. In this review, we reviewed some of its molecular mechanisms of action and summarized animal and human studies regarding resveratrol and female infertility, with a focus on age-related infertility, polycystic ovary syndrome, and endometriosis.

Epigenetic Dysregulation in Endometriosis: Implications for Pathophysiology and Therapeutics

Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying an epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in controlling epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation, with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis and resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.

Histone acetyltransferases and histone deacetyl transferases play crucial role during oogenesis and early embryo development

Dynamic epigenetic regulation is critical for proper oogenesis and early embryo development. During oogenesis, fully grown germinal vesicle oocytes develop to mature Metaphase II oocytes which are ready for fertilization. Fertilized oocyte proliferates mitotically until blastocyst formation and the process is called early embryo development. Throughout oogenesis and early embryo development, spatio-temporal gene expression takes place, and this dynamic gene expression is controlled with the aid of epigenetics. Epigenetic means that gene expression can be altered without changing DNA itself. Epigenome is regulated through DNA methylation and histone modifications. While DNA methylation generally ends up with repression of gene expression, histone modifications can result in expression or repression depending on type of modification, type of histone protein and its specific residue. One of the modifications is histone acetylation which generally ends up with gene expression. Histone acetylation occurs through the addition of acetyl group onto amino terminal of the core histone proteins by histone acetyltransferases (HATs). Contrarily, histone deacetylation is associated with repression of gene expression, and it is catalyzed by histone deacetylases (HDACs). This review article focuses on what is known about alterations in the expression of HATs and HDACs and emphasizes importance of HATs and HDACs during oogenesis and early embryo development.

Histone modifications in embryo implantation and placentation: insights from mouse models

Embryo implantation and placentation play pivotal roles in pregnancy by facilitating crucial maternal-fetal interactions. These dynamic processes involve significant alterations in gene expression profiles within the endometrium and trophoblast lineages. Epigenetics regulatory mechanisms, such as DNA methylation, histone modification, chromatin remodeling, and microRNA expression, act as regulatory switches to modulate gene activity, and have been implicated in establishing a successful pregnancy. Exploring the alterations in these epigenetic modifications can provide valuable insights for the development of therapeutic strategies targeting complications related to pregnancy. However, our current understanding of these mechanisms during key gestational stages remains incomplete. This review focuses on recent advancements in the study of histone modifications during embryo implantation and placentation, while also highlighting future research directions in this field.

Mitochondrial energy metabolism is downregulated in repeated implantation failure patients related to alteration of PGC-1α acetylation level

Herein we aimed at exploring mitochondrial energy metabolism status in patients with repeated implantation failure (RIF) and whether key regulatory factor PGC-1α of energy metabolism is involved in the decidualization of endometrial stromal cells. Mitochondrial oxidative phosphorylation level and ATP synthesis were compared in primary endometrial stromal cells from RIF and control group. At the same time, as one of key transcription regulators of mitochondrial energy metabolism, the expression level and acetylation level of PGC-1α were compared with two groups. Then, we downregulated the acetylation levels of PGC-1α, and the expression of decidual markers (PRL and IGFBP1) was observed further. Mitochondrial energy metabolism, showing by mitochondrial oxidative phosphorylation level and ATP synthesis, was decreased in the endometrial stromal cells of the RIF group (RIF-hEnSCs). Meanwhile, PGC-1α acetylation levels were significantly higher in RIF-hEnSCs. When we reduced the acetylation levels of PGC-1α in RIF-hEnSCs, the basal O₂ consumption rate and maximal respiration were increased, and also the PRL and IGFBP1. Overall, our data indicated that the endometrial stromal cells of the RIF patients had low level of mitochondrial energy metabolism. Reducing acetylation level of key energy metabolism regulator PGC-1α can increase the decidualization level of RIF-hEnSCs. These findings may inspire new ideas about the treatment of RIF.

Roles of lipid metabolism and its regulatory mechanism in idiopathic pulmonary fibrosis: A review

Idiopathic pulmonary fibrosis is a progressive lung disease of unknown etiology characterized by distorted distal lung architecture, inflammation, and fibrosis. Several lung cell types, including alveolar epithelial cells and fibroblasts, have been implicated in the development and progression of fibrosis. However, the pathogenesis of idiopathic pulmonary fibrosis is still incompletely understood. The latest research has found that dysregulation of lipid metabolism plays an important role in idiopathic pulmonary fibrosis. The changes in the synthesis and activity of fatty acids, cholesterol and other lipids seriously affect the regenerative function of alveolar epithelial cells and promote the transformation of fibroblasts into myofibroblasts. Mitochondrial function is the key to regulating the metabolic needs of a variety of cells, including alveolar epithelial cells. Sirtuins located in mitochondria are essential to maintain mitochondrial function and cellular metabolic homeostasis. Sirtuins can maintain normal lipid metabolism by regulating respiratory enzyme activity, resisting oxidative stress, and protecting mitochondrial function. In this review, we aimed to discuss the difference between normal and idiopathic pulmonary fibrosis lungs in terms of lipid metabolism. Additionally, we highlight recent breakthroughs on the effect of abnormal lipid metabolism on idiopathic pulmonary fibrosis, including the effects of sirtuins. Idiopathic pulmonary fibrosis has its high mortality and limited therapeutic options; therefore, we believe that this review will help to develop a new therapeutic direction from the aspect of lipid metabolism in idiopathic pulmonary fibrosis.