Retinoic acid-induced CYP51 nuclear translocation promotes meiosis prophase I process and is correlated to the expression of REC8 and STAG3 in mice

Strategies of targeting CYP51 for IFIs therapy: Emerging prospects, opportunities and challenges

CYP51, a monooxygenase associated with the sterol synthesis pathway, is responsible for the catalysis of the 14-methyl hydroxylation reaction of lanosterol precursors. This enzyme is widely present in microorganisms, plants, and mammals. In mammals, CYP51 plays a role in cholesterol production, oligodendrocyte formation, oocyte maturation, and spermatogenesis. In fungal cells, CYP51 is an enzyme that synthesizes membrane sterols. By inhibiting fungal CYP51, ergosterol synthesis can be inhibited and ergosterol membrane fluidity is altered, resulting in fungal cell apoptosis. Thus, targeting CYP51 is a reliable antifungal strategy with important implications for the treatment of invasive fungal infections (IFIs). Many CYP51 inhibitors have been approved by the FDA for clinical treatment. However, several limitations of CYP51 inhibitors remain to be resolved, including fungal resistance, hepatotoxicity, and drug-drug interactions. New broad-spectrum, anti-resistant, highly selective CYP51 inhibitors are expected to be developed to enhance clinical efficacy and minimize adverse effects. Herein, we summarize the structural features and biological functions of CYP51 and emphatically analyze the structure-activity relationship (SAR) and therapeutic potential of different chemical types of small-molecule CYP51 inhibitors. We also discuss the latest progress of novel strategies, providing insights into new drugs targeting CYP51 for clinical practice.

Primordial Follicle Formation - Some Assembly Required

Formation of primordial follicles occurs when germ cell nests break apart and individual oocytes become surrounded by pregranulosa cells. Why mammalian germ cells develop in germ cell nests is not fully understood but recent work has provided evidence that some oocytes serve as nurse cells supporting other oocytes in the cyst. Headway has also been made in understanding interactions that occur between cyst cells that must change as individual oocytes separate to associate with pregranulosa cells. As germ cell nests undergo breakdown some oocytes are lost by programmed cell death that has been attributed to apoptosis, but newer studies have implicated autophagy in counteracting apoptosis to promote cell survival and maintain the ovarian reserve. Work in the past few years has added to already known pathways regulating primordial follicle formation and has identified new players including signaling molecules, transcription factors and RNA binding proteins.

Novel Hybrid Acetylcholinesterase Inhibitors Induce Differentiation and Neuritogenesis in Neuronal Cells in vitro Through Activation of the AKT Pathway

BACKGROUND

Alzheimer's disease (AD) is characterized by a progressive loss of episodic memory associated with amyloid-β peptide aggregation and the abnormal phosphorylation of the tau protein, leading to the loss of cholinergic function. Acetylcholinesterase (AChE) inhibitors are the main class of drugs used in AD therapy.

OBJECTIVE

The aim of the current study was to evaluate the potential of two tacrine-donepezil hybrid molecules (TA8Amino and TAHB3), which are AChE inhibitors, to induce neurodifferentiation and neuritogenesis in SH-SY5Y cells.

METHODS

The experiments were carried out to characterize neurodifferentiation, cellular changes related to responses to oxidative stress and pathways of cell survival in response to drug treatments.

RESULTS

The results indicated that the compounds did not present cytotoxic effects in SH-SY5Y or HepG2 cells. TA8Amino and TAHB3 induced neurodifferentiation and neuritogenesis in SH-SY5Y cells. These cells showed increased levels of intracellular and mitochondrial reactive oxygen species; the induction of oxidative stress was also demonstrated by an increase in SOD1 expression in TA8Amino and TAHB3-treated cells. Cells treated with the compounds showed an increase in PTEN(Ser380/Thr382/383) and AKT(Ser473) expression, suggesting the involvement of the AKT pathway.

CONCLUSION

Our results demonstrated that TA8Amino and TAHB3 present advantages as potential drugs for AD therapy and that they are capable of inducing neurodifferentiation and neuritogenesis.

Inferring lanosterol functions in the female rabbit reproductive tract based on the immunolocalization of lanosterol 14-demethylase and farnesoid beta-receptor

Female reproductive organs have de novo synthesis of cholesterol. Some sterol molecules, intermediaries in the cholesterol synthesis, have important paracrine/autocrine actions. Lanosterol binds to the farnesoid beta-receptor (FXRβ), a molecule widely expressed in the ovaries, suggesting that it may play a role in reproduction. Up to date, we know little about lanosterol functions across female reproductive organs. We described immunolocalized lanosterol 14-demethylase (LDM or CYP51A1), responsible for catalyzing the conversion of lanosterol in cholesterol, and FXRβ in the ovary, oviduct, uterus, and vagina of virgin and pregnant rabbits. In virgin rats, we found CYP51A1 and FXRβ immunoreactivity was found in all ovarian follicles, epithelial cells, stroma, and Graafian follicles. Also, the epithelium and stroma, as well as the smooth muscle of the oviduct, vagina, and uterus showed CYP51A1 and FXRβ immunoreactivity. In pregnant dams, we observed the presence of CYP51A1 and FXRβ immunoreactivity in the corpora lutea, giant uterine cells, and trophoblastic cells. The presence of CYP51A1 and FXRβ support that lanosterol participates in diverse reproductive processes, including follicular maturation, transport of gametes and zygote, implantation of blastocyst, lubrication, and contraction of the vagina, secretion of female prostate, and control of delivery mediated by pelvic muscles contraction.

Retinoic acid signaling in regulation of meiosis during embryonic development in mice

In the embryonic gonads of mice, the genetic and epigenetic regulatory programs for germ cell sex specification and meiosis induction or suppression are intertwined. The quest for garnering comprehensive understanding of these programs has led to the emergence of retinoic acid (RA) as an important extrinsic factor, which regulates initiation of meiosis in female fetal germ cells that have attained a permissive epigenetic ground state. In contrast, germ cells in fetal testis are protected from the exposure to RA due to the activity of CYP26B1, an RA metabolizing enzyme, which is highly expressed in fetal testis. In this review, we provide an overview of the molecular mechanisms operating in fetal gonads of mice, which enable regulation of meiosis via RA signaling.