DNA methylation is known as the prima donna epigenetic mark for its critical role in regulating local gene transcription. Changes in the landscape of DNA methylation across the genome occur during cellular transition, such as differentiation and altered neuronal plasticity, and become dysregulated in disease states such as cancer. The TET family of enzymes is known to be responsible for catalyzing the reverse process that is DNA demethylation by recognizing 5-methylcytosine and oxidizing the methyl group via an Fe(II)/alpha-ketoglutarate-dependent mechanism. Here, we describe the design, synthesis, and evaluation of novel cytosine-based TET enzyme inhibitors, a class of small molecule probes previously underdeveloped but broadly desired in the field of epigenetics. We identify a promising cytosine-based lead compound, Bobcat339, that has mid-μM inhibitor activity against TET1 and TET2, but does not inhibit the DNA methyltransferase, DNMT3a. In silico modeling of the TET enzyme active site is used to rationalize the activity of Bobcat339 and other cytosine-based inhibitors. These new molecular tools will be useful to the field of epigenetics and serve as a starting point for new therapeutics that target DNA methylation and gene transcription.

Chronic stress induces endocrine disturbance, which contributes to the development of polycystic ovary syndrome (PCOS), a condition that remains a challenge for clinicians to cope with. The present study investigated the effect of Xiao-Yao-San (XYS), a traditional Chinese medicine formula used for treatment of gynecological disease, on the chronic stress-induced polycystic ovary and its underlying mechanism. Female Sprague-Dwaley rats underwent a 3 weeks chronic unpredictable mild stress (CUMS) procedure to establish the PCOS model, followed by 4 weeks treatment with XYS (0.505 g/kg or 1.01 g/kg) by gavage. Granulosa cells were exposed to noradrenaline (1 mM) in vitro for 24 h, followed by incubation with or without XYS-treated rat serum for 24 h. Post-treatment with XYS ameliorated CUMS-induced irregular estrous cycles and follicles development abnormalities, decrease of estradiol and progesterone level as well as increase of luteinizing hormone in serum, reduced cystic follicles formation and the apoptosis and autophagy of granulosa cells, attenuated the increase in dopamine beta hydroxylase and c-fos level in locus coeruleus, the noradrenaline level in serum and ovarian tissue, and the expression of beta 2 adrenergic receptor in ovarian tissue. Besides, XYS alleviated the reduction of phosphorylation of ribosomal protein S6 kinase polypeptide I and protein kinase B, as well as the increase of microtubule-associated protein light chain 3-I to microtubule-associated protein light chain 3-II conversion both in vivo and in vitro. This study demonstrated XYS as a potential strategy for CUMS induced polycystic ovary, and suggested that the beneficial role of XYS was correlated with the regulation of the sympathetic nerve activity.

LPS-induced microvascular hyperpermeability and hemorrhage play a key role in the development of sepsis, the attenuation of which might be an important strategy to prevent sepsis. However, the current clinical therapies have proven to be inefficient in improving the prognosis for patients with sepsis. Catalpol, an iridoid glycoside extracted from the roots of Rehmannia, has been reported to protect against LPS-induced acute lung injury through a Toll-like receptor-4 (TLR-4)-mediated NF-κB signaling pathway. However, it is still unknown whether catalpol can be an effective treatment to ameliorate the LPS-induced microvascular disorder. The present study aimed to investigate the impact of catalpol on LPS-induced mesenteric microvascular disorder and its underlying mechanism. Male Wistar rats were challenged by infusion of LPS (10 mg·kg·h) through the left femoral vein for 120 min. Post-treatment with catalpol (10 mg/kg) alleviated the LPS-induced microvascular hyperpermeability and hemorrhage; reduced mortality; ameliorated the alteration in the distribution of claudin-5 and the junctional adhesion molecule-1, as well as the degradation of collagen IV and laminin; and attenuated the increase of TLR-4 level, phosphorylations of Src tyrosine kinase, phosphatidyl inositol 3-kinase, focal adhesion kinase, and cathepsin B activation. In vitro study in human umbilical vein endothelial cells verified these results and further revealed that inhibition of TLR-4 and Src each simulated some, but not all, of the effects that catalpol exerted. Besides, surface plasmon resonance showed that catalpol could directly bind to TLR-4 and Src. These results demonstrated that catalpol was able to ameliorate the LPS-induced microvascular barrier damage and hemorrhage by targeting both TLR-4 and Src, thus attenuating the phosphorylation of Src kinase, phosphatidyl inositol 3-kinase, and focal adhesion kinase, as well as cathepsin B activation.