Showing papers on "Lanosterol published in 2020"

Inhibition of ergosterol synthesis in Candida albicans by novel eugenol tosylate congeners targeting sterol 14α-demethylase (CYP51) enzyme

Abstract: This study is a continuation and extension of our previous study in which we synthesized seven novel eugenol tosylate congeners (ETC-1 to ETC-7) from a natural compound eugenol and checked their antifungal activity against different isolates of Candida albicans. All these ETCs showed potent antifungal activity to varying degrees. In this study, the aim is to evaluate the effect of most active compounds (ETC-5, ETC-6 and ETC-7) on ergosterol biosynthesis pathway and cellular viability in C. albicans by applying combined approach of in silico and in vitro methodologies. In silico studies were done through all atom molecular mechanics approach and free binding energy estimations, and in vitro study was done by estimating total intracellular sterol content and effect on expression of ERG11 gene. Furthermore, effect on cell viability by these compounds was also tested. Our results demonstrated that these ETCs target ergosterol biosynthesis pathway in C. albicans by inhibiting the lanosterol 14-α demethylase enzyme and also downregulates expression of its related gene ERG11. Furthermore, these ETCs exhibit potent fungicidal effect in cell viability assay, thus overall results advocating the claim that these tosylates have potential to be taken to next level of antifungal drug development.

The cholesterol synthesis enzyme lanosterol 14α-demethylase is post-translationally regulated by the E3 ubiquitin ligase MARCH6

Abstract: Cholesterol synthesis is a tightly controlled pathway, with over 20 enzymes involved. Each of these enzymes can be distinctly regulated, helping to fine-tune the production of cholesterol and its functional intermediates. Several enzymes are degraded in response to increased sterol levels, whilst others remain stable. We hypothesised that an enzyme at a key branch point in the pathway, lanosterol 14α-demethylase (LDM) may be post-translationally regulated. Here, we show that the preceding enzyme, lanosterol synthase is stable, whilst LDM is rapidly degraded. Surprisingly, this degradation is not triggered by sterols. However, the E3 ubiquitin ligase membrane-associated ring-CH-type finger 6 (MARCH6), known to control earlier rate-limiting steps in cholesterol synthesis, also control levels of LDM and the terminal cholesterol synthesis enzyme, 24-dehydrocholesterol reductase. Our work highlights MARCH6 as the first example of an E3 ubiquitin ligase that targets multiple steps in a biochemical pathway and indicates new facets in the control of cholesterol synthesis.

Biosynthetic Mechanism of Lanosterol: A Completed Story

Abstract: The remarkable biochemical conversion of acyclic 2,3-oxidosqualene to tetracyclic lanosterol (the common precursor to cholesterol and its relatives) with seven stereocenters constructed, catalyzed ...

The Intravitreal Injection of Lanosterol Nanoparticles Rescues Lens Structure Collapse at an Early Stage in Shumiya Cataract Rats.

Abstract: We designed an intravitreal injection formulation containing lanosterol nanoparticles (LAN-NPs) via the bead mill method and evaluated the therapeutic effect of LAN-NPs on lens structure collapse and opacification using two rat cataract models (SCR-N, rats with slight lens structure collapse; SCR-C, rats with the combination of a remarkable lens structure collapse and opacification). The particle size of lanosterol in the LAN-NPs was around 50-400 nm. A single injection of LAN-NPs (0.5%) supplied lanosterol into the lens for 48 h, and no irritation or muddiness was observed following repeated injections of LAN-NPs for 6 weeks (once every 2 days). Moreover, LAN-NPs repaired the slight collapse of the lens structure in SCR-N. Although the remarkable changes in the lens structure of SCR-C were not repaired by LAN-NP, the onset of opacification was delayed. In addition, the increase of cataract-related factors (Ca2+ contents, nitric oxide levels, lipid peroxidation and calpain activity levels) in the lenses of SCR-C was attenuated by the repeated injection of LAN-NPs. It is possible that a deficiency of lanosterol promotes the production of oxidative stress. In conclusion, it is difficult to improve serious structural collapse with posterior movement of the lens nucleus with a supplement of lanosterol via LAN-NPs. However, the intravitreal injection of LAN-NPs was found to repair the space and structural collapse in the early stages in the lenses.

Solubility of Lanosterol in Organic Solvents and in Water-Alcohol Mixtures at 101.8 kPa

Abstract: Lanosterol is a sterol derivative whose physicochemical properties are poorly understood. Pure lanosterol (>95%) was isolated from a crude product (54.6%) by a newly developed C18 reverse-phase hig...

The unique sterol biosynthesis pathway of three model diatoms consists of a conserved core and diversified endpoints

Abstract: Diatoms produce a wide diversity of sterols among different species, the biosynthesis and conservation of which is not yet fully understood. To investigate the conservation and divergence of sterol biosynthesis pathways among diatoms, we performed comparative metabolic profiling and transcriptomics for a centric diatom (Thalassiosira pseudonana), a pennate diatom (Phaeodactylum tricornutum) and a chaetocerid (Chaetoceros muelleri) in response to inhibitors of enzymes involved in sterol biosynthesis. These three model diatoms, which are representative of distinct clades, share a unique core phytosterol biosynthesis pathway that relies on a terbinafine-insensitive alternative squalene epoxidase and the cyclization of 2,3-epoxysqualene into cycloartenol by a conserved oxidosqualene cyclase. Lineage-specific divergence in the synthesis of sterol precursors was found in the species analyzed. Cholesterol synthesis in diatoms seems to occur via cycloartenol rather than lanosterol. The diversification of natural sterols produced by each species appears to occur downstream of all experimentally targeted enzymes, suggesting adaptive specialization in terminal synthesis pathways.

Oxidation of Isodrimeninol with PCC Yields Drimane Derivatives with Activity against Candida Yeast by Inhibition of Lanosterol 14-Alpha Demethylase.

Abstract: Candida species cause an opportunistic yeast infection called Candidiasis, which is responsible for more than 50,000 deaths every year around the world. Effective treatments against candidiasis caused by non-albicans Candida species such as C. glabrata, C. parapsilosis, C. aureus, and C. krusei are limited due to severe resistance to conventional antifungal drugs. Natural drimane sesquiterpenoids have shown promising antifungal properties against Candida yeast and have emerged as valuable candidates for developing new candidiasis therapies. In this work, we isolated isodrimeninol (C1) from barks of Drimys winteri and used it as starting material for the hemi-synthesis of four sesquiterpenoids by oxidation with pyridinium chlorochromate (PCC). The structure of the products (C2, C3, C4, and C5) was elucidated by 1D and 2D NMR spectroscopy resulting in C4 being a novel compound. Antifungal activity assays against C. albicans, C. glabrata, and C. krusei revealed that C4 exhibited an increased activity (IC50 of 75 μg/mL) compared to C1 (IC50 of 125 μg/mL) in all yeast strains. The antifungal activity of C1 and C4 was rationalized in terms of their capability to inhibit lanosterol 14-alpha demethylase using molecular docking, molecular dynamics simulations, and MM/GBSA binding free energy calculations. In silico analysis revealed that C1 and C4 bind to the outermost region of the catalytic site of 14-alpha demethylase and block the entrance of lanosterol (LAN) to the catalytic pocket. Binding free energy estimates suggested that C4 forms a more stable complex with the enzyme than C1, in agreement with the experimental evidence. Based on this new approach it is possible to design new drimane-type sesquiterpenoids for the control of Candida species as inhibitors of 14-alpha demethylase.

Carbohydrate hitched imidazoles as agents for the disruption of fungal cell membrane.

Abstract: The fungal diseases represent an increasing global health burden and have transformed from a rare curiosity to the leading cause of human mortality. The present manuscript reports the antifungal potential of two novel compounds possessing a carbohydrate and an imidazole moiety. Antifungal susceptibility test determined the growth inhibition potential of the synthesized compounds against Aspergillus niger 9689 and it was observed that compounds D and E gave an antifungal inhibitory index of 66.66 and 56.67% respectively. Further, ultra-structure analysis of the treated fungal mycelia through scanning electron microscope (SEM) and confocal microscopy indicated significant membrane permeability and disintegration of fungal cell membrane, thus highlighting the probable role of the synthesized compounds as inhibitors of fungal lanosterol 14α-demethylase. In silico studies corroborated with the in-vitro results, as the synthesized compounds interacted with the critical amino acids present at the active site of the fungal enzyme (lanosterol 14α-demethylase).

Optimization of mass spectrometry settings for steroidomic analysis in young and old killifish.

Abstract: Steroids are essential structural components of cell membranes that organize lipid rafts and modulate membrane fluidity. They can also act as signalling molecules that work through nuclear and G protein-coupled receptors to impact health and disease. Notably, changes in steroid levels have been implicated in metabolic, cardiovascular and neurodegenerative diseases, but how alterations in the steroid pool affect ageing is less well understood. One of the major challenges in steroidomic analysis is the ability to simultaneously detect and distinguish various steroids due to low in vivo concentrations and naturally occurring stereoisomers. Here, we established such a method to study the mass spectrometry behaviour of nine sterols/steroids and related molecules (cholesterol precursors: squalene, lanosterol; sterol metabolites; 7 Dehydrocholesterol, 24, 25 and 27 Hydroxycholesterol; and steroids: progesterone, testosterone, and corticosterone) during ageing in the African turquoise killifish, a new model for studying vertebrate longevity. We find that levels of all tested steroids change significantly with age in multiple tissues, suggesting that specific steroids could be used as biomarkers of ageing. These findings pave the way for use of Nothobranchius furzeri as a novel model organism to unravel the role of sterols/steroids in ageing and age-related diseases. Graphical abstract.

Sterols from the Post-Lanosterol Part of Cholesterol Synthesis: Novel Signaling Players

Abstract: While steroid hormones are well-recognized signaling molecules that bind to steroid hormone receptors there is a gap in our knowledge regarding other sterol molecules, particularly the intermediates of cholesterol synthesis. Lanosterol is the first sterol in the cholesterol synthesis pathway and theoretically, 72 different sterols can be formed before cholesterol is produced. These sterols are similar molecules by chemical properties and differ mostly by the number of double bonds and substituents on the sterol ring. While textbooks still claim that sterol intermediates of the cholesterol biosynthetic pathway are dedicated to cholesterol, there is increasing evidence that each of these sterols has a biological role, but not all have yet been discovered. In this chapter, we review the current knowledge about the post-lanosterol sterols of cholesterol synthesis and review the directions of current research in this field.

Phytochemicals as potential inhibitors of lanosterol 14 α-demethylase (cyp51) enzyme: an in silico study on sixty molecules

Abstract: Lanosterol 14 α-demethylase (CYP51) is a key protein involved in ergosterol biosynthesis of Candida albicans and a crucial target for ergosterol synthesis inhibition. However, in the last two decades drug resistance is reported under clinical situations to most of the prescribed antifungal drugs like azole group of drugs. In this study, molecular docking of sixty plant molecules with Lanosterol 14 α-demethylase protein has been done. The homology modeling tool PHYRE2 was used to predict the structure of Lanosterol 14 α-demethylase. Predicted structure was used for docking studies with sixty plant molecules by using Autodock 1.5.6 cr2™. Among the sixty plant molecules, forty-seven were found to form hydrogen bond and the rest of the plant molecules did not form a hydrogen bond with Lanosterol 14 α-demethylase. Docking study of a library of sixty molecules revealed that 48 plant molecules showed an excellent and good binding affinity with predicted protein model Lanosterol 14 α-demethylase of Candida albicans. The binding residue comparison of docked molecules with that of Ketoconazole revealed, fourteen molecules have similar binding residue. These fourteen molecules may have a similar mode of action as that of Ketoconazole. These molecules should be screened and used to discover new antifungal therapeutic drugs.

Involvement of 27-Hydroxycholesterol in Mitotane Action on Adrenocortical Carcinoma.

Abstract: Adrenocortical carcinoma (ACC) is a rare cancer with poor prognosis. Mitotane, the standard treatment for ACC, impairs adrenocortical steroid biosynthesis and cholesterol metabolism. In the H295R cell line, a standard ACC in vitro model, mitotane was previously reported to enhance the production of some oxysterols. To verify the possible mechanistic involvement of oxysterols in the anti-ACC effect of mitotane, a gas chromatography mass spectrometry (GC-MS) profiling of oxysterols and the main cholesterol precursors was carried out in H295R cells. Among the oxysterols detected in mitotane-treated cells, 27OHC was markedly produced, as well as lanosterol and lathosterol cholesterol precursors. In this cell model, mitotane was confirmed to affect mitochondrial transmembrane potential and induce apoptosis. Such cytotoxic effects were perfectly matched by H295R cell treatment with a single identical micromolar amount of 27OHC. The mitotane-dependent strong increase in 27OHC was confirmed in vivo, in the plasma of ACC patients under treatment with the drug. Moreover, lanosterol, lathosterol, desmosterol and, to a minor extent, 24-hydroxycholesterol and 25-hydroxycholesterol plasma levels were significantly increased in those patients. The cytotoxic effect of mitotane on ACC cells may be partly related to the increased intracellular level of 27OHC induced by the drug itself.

Isolation and identification of antibacterial compound from common name Holothuria leucospilota in the Persian Gulf

Abstract: Echinodermata are one of the most important branches of invertebrate in marine ecosystems, which today are also known as a rich source of natural products with biological properties. Most of these properties belong to compounds with a terpenoid structure. According to the biological properties of sea cucumbers in the Persian Gulf, this scientific study investigates the antibacterial properties of lanosterol compounds extracted from Holothuria leucospilota of Hengam Island in Persian Gulf. The cucumber powder was extracted using acetone, then the extract purified by silica gel column chromatography with n-hexane and ethyl acetate combination to isolate the terpenoid compounds. Isolated compound were run through TLC and sprayed with vanillin-sulphuric acid reagent for detection of terpenoid compound and profile of isolated compound obtained by gas chromatography (GC). The lanosterol triterpenoid compound in column fraction was identified by GC. Antimicrobial properties were evaluated by dilution test on bacterial strain Escherichia coli, Pseudomonas aeruginosa, Klebsiella nemonya, Proteus vulgaris, Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Nocardia brazilinus. This compound has antibacterial effects on gram-positive bacteria (Bacillus subtilis, Bacillus cereus and Staphylococcus aureus). Antibacterial effects of the lanosterol indicate that it can be very effective in antibiotics production.

The Polymorphism rs2968 of LSS Gene Confers Susceptibility to Age-Related Cataract.

Abstract: Research showed that lanosterol can decrease protein aggregation in lens and reduce cataract formation. Lanosterol synthase (LSS) and 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) are the...

From Design to in Vivo Active Organometallic-Containing Antimycotic Agents

Abstract: Fungal infections are an alarming global problem, most importantly for immunocompromised patients in a hospital environment. The appearance of multidrug resistance in several fungal species is a strong indication that alternative treatments are required. Azoles represent the mainstay of antifungal drugs, and their mode of action involves the binding mode of these molecules to the fungal lanosterol 14α-demethylase target enzyme. In this work, by rational design, we have prepared and characterized four novel organometallic derivatives of the frontline antifungal drug fluconazole (1a-4a). All compounds showed excellent in vitro activity against the yeast C. robusta, clearly surpassing the progenitor organic drug fluconazole. As anticipated, due to the presence of the ferrocenyl moiety in 1a-4a, a modest increase in ROS generation was observed on C. robusta upon treatment. Very importantly, enzyme inhibition and chemogenetic profiling demonstrated that lanosterol 14α-demethylase was the main target of the most active compound of the series, (N-(ferrocenylmethyl)-2-(2,4-difluorophenyl)-2-hydroxy-N-methyl-3-(1H-1,2,4-triazol-1-yl)propan-1-aminium chloride, 2a). Transmission electron microscopy (TEM) studies suggested that 2a induced a loss in wall integrity as well as intracellular features ascribable to late apoptosis or necrosis. The impressive activity of 2a was further confirmed on clinical isolates, where antimycotic potency up to 400 times higher than fluconazole was observed. Also, 2a showed activity towards azole-resistant strains. This finding is very interesting since the target of 2a is primarily the same as that of fluconazole, emphasizing the role played by the organometallic moiety. In vivo experiments conducted with 2a at a dose of 10 mg/Kg in mice model of Candida infections, while not decreasing fungal burden in the kidney, reduced distal distribution to liver and brain and greatly improved the inflammatory pathology in the kidney and colon, compared to untreated mice.

Method to treat or prevent cataract

Abstract: The present invention relates to pharmacology, namely to treating ophthalmic diseases. Provided is a method of treating or preventing cataract in a subject in need thereof, comprising administering in the eye of said subject a composition comprising a pharmaceutically acceptable carrier and a pharmaceutically effective amount of lanosterol. Lanosterol inhibits crystallin protein aggregation or dissolves crystallin protein aggregate.

Composition of lanosterol prodrug compound, preparation method therefor and use thereof

Abstract: Disclosed are a composition comprising a compound as shown in formula (I) and a preparation method therefor, and the use of same in the preparation of a drug for treating ophthalmic diseases.

Evolutionary conserved nitric oxide synthesis proteins responding to bacterial MAMPs are located to the endoplasmic reticulum and are also involved in secondary metabolite synthesis and sterol production

Abstract: Nitric oxide is (NO) known to be produced by most Eukaryotic organisms although the NO production mechanism is only known for animals (Canovas et al., 2016). Mammals have a set of different nitric oxide synthases (NOSs) with basically similar mechanism for producing NO under different circumstances (Velayutham and Zweier, 2013; Yu et al., 2014). NO-production is characteristically induced as part of innate immunity reactions to bacterial Microbial Associated Molecular Patterns (MAMPs). We knew from our previous work that the plant pathogen Fusarium graminearum quickly upregulates genes characteristic for an innate immune response so we set out to test if it also produces NO as part of this response and find the responsible genes if it does. We found that F. graminearum produces NO in response to bacterial MAMPs and that the NO production system must be similar in fungi as in mammals where NO is activated by a homo-dimerization of nitric oxide synthetase proteins (NOSs) containing an N-terminal cytochrome P450 domain (CYP) and a C-terminal NADPH dependent cytochrome P450 reductase (NCP) domain. The electrons are transferred from the C-terminal NCP domains to the CYP domain in the paired protein to produce NO. We could not find a candidate NOS in the fungus. Thus, we tested the hypothesis that an NCP-protein similar to the NCP part of a NOS is brought together with a CYP-protein to produce NO in another way than the dimerization of a classic NOS. We found that in F. graminearum NO is produced by an FgNCP and an FgCYP located to the endoplasmic reticulum membrane where both proteins are predicted to be N-terminally attached by a transmembrane or embedded hydrophobic alpha helix. Deletion of any of these proteins lowered pathogenicity to wheat and radically reduced NO-production. Knockout of the FgNCP also completely blocked deoxynivalenol synthesis needed for pathogenicity indicating that the FgNCP also delivers electrons to another CYP (TRI4) located at the ER. The FgCYP we found to be involved in NO-productions is the same or similar to proteins involved in Eukaryote sterol synthesis (CYP51) reducing lanosterol on the way to the final main sterols different for different Eukaryotes. Lanosterol enriched membranes are known to be inhibited in endocytosis and we found that the deletion of the FgCYP producing NO also completely stopped endocytosis. We further tested consequences of these indications of more than one function and suggest the CYP-protein is most likely an FgCYPNO,ERG involved in both NO and ergosterol synthesis and the NCP is involved in NO, trichothecene and ergosterol synthesis, an FgNCPNO,TRI,ERG. The two proteins shown here to be responsible for NO production in F. graminearum are both highly conserved in Eukaryotes from amoeba to human and homologues are likely candidates for the production of NO in many other eukaryotes including mammals. The multiple functions of these proteins can be part of the explanation for the links between chronic inflammation, sterols and blood pressure in human.