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Science Immunology Jul 2022Acne affects 1 in 10 people globally, often resulting in disfigurement. The disease involves excess production of lipids, particularly squalene, increased growth of ,...
Acne affects 1 in 10 people globally, often resulting in disfigurement. The disease involves excess production of lipids, particularly squalene, increased growth of , and a host inflammatory response with foamy macrophages. By combining single-cell and spatial RNA sequencing as well as ultrahigh-resolution Seq-Scope analyses of early acne lesions on back skin, we identified TREM2 macrophages expressing lipid metabolism and proinflammatory gene programs in proximity to hair follicle epithelium expressing squalene epoxidase. We established that the addition of squalene induced differentiation of TREM2 macrophages in vitro, which were unable to kill . The addition of squalene to macrophages inhibited induction of oxidative enzymes and scavenged oxygen free radicals, providing an explanation for the efficacy of topical benzoyl peroxide in the clinical treatment of acne. The present work has elucidated the mechanisms by which TREM2 macrophages and unsaturated lipids, similar to their involvement in atherosclerosis, may contribute to the pathogenesis of acne.
Topics: Acne Vulgaris; Humans; Inflammation; Lipids; Macrophages; Membrane Glycoproteins; Receptors, Immunologic; Squalene
PubMed: 35867799
DOI: 10.1126/sciimmunol.abo2787 -
Nature Jun 2022All known triterpenes are generated by triterpene synthases (TrTSs) from squalene or oxidosqualene. This approach is fundamentally different from the biosynthesis of...
All known triterpenes are generated by triterpene synthases (TrTSs) from squalene or oxidosqualene. This approach is fundamentally different from the biosynthesis of short-chain (C-C) terpenes that are formed from polyisoprenyl diphosphates. In this study, two fungal chimeric class I TrTSs, Talaromyces verruculosus talaropentaene synthase (TvTS) and Macrophomina phaseolina macrophomene synthase (MpMS), were characterized. Both enzymes use dimethylallyl diphosphate and isopentenyl diphosphate or hexaprenyl diphosphate as substrates, representing the first examples, to our knowledge, of non-squalene-dependent triterpene biosynthesis. The cyclization mechanisms of TvTS and MpMS and the absolute configurations of their products were investigated in isotopic labelling experiments. Structural analyses of the terpene cyclase domain of TvTS and full-length MpMS provide detailed insights into their catalytic mechanisms. An AlphaFold2-based screening platform was developed to mine a third TrTS, Colletotrichum gloeosporioides colleterpenol synthase (CgCS). Our findings identify a new enzymatic mechanism for the biosynthesis of triterpenes and enhance understanding of terpene biosynthesis in nature.
Topics: Ascomycota; Colletotrichum; Cyclization; Diphosphates; Squalene; Substrate Specificity; Talaromyces; Triterpenes
PubMed: 35650436
DOI: 10.1038/s41586-022-04773-3 -
Environmental Science & Technology Jun 2022This critical review describes the squalene-ozone (SqOz) reaction, or squalene ozonolysis. Ambient ozone penetrates indoors and drives indoor air chemistry. Squalene, a... (Review)
Review
This critical review describes the squalene-ozone (SqOz) reaction, or squalene ozonolysis. Ambient ozone penetrates indoors and drives indoor air chemistry. Squalene, a component of human skin oil, contains six carbon-carbon double bonds and is very reactive with ozone. Bioeffluents from people contribute to indoor air chemistry and affect the indoor air quality, resulting in exposures because people spend the majority of their time indoors. The SqOz reaction proceeds through various formation pathways and produces compounds that include aldehydes, ketones, carboxylic acids, and dicarbonyl species, which have a range of volatilities. In this critical review of SqOz chemistry, information on the mechanism of reaction, reaction probability, rate constants, and reaction kinetics are compiled. Characterizations of SqOz reaction products have been done in laboratory experiments and real-world settings. The effect of multiple environmental parameters (ozone concentration, air exchange rate (AER), temperature, and relative humidity (RH)) in indoor settings are summarized. This critical review concludes by identifying the paucity of available exposure, health, and toxicological data for known reaction products. Key knowledge gaps about SqOz reactions leading to indoor exposures and adverse health outcomes are provided as well as an outlook on where the field is headed.
Topics: Air Pollutants; Air Pollution, Indoor; Carbon; Humans; Kinetics; Ozone; Squalene
PubMed: 35648815
DOI: 10.1021/acs.est.1c07611 -
Natural Product Reports Dec 2018Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014... (Review)
Review
Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.
Topics: Molecular Structure; Oleanolic Acid; Saponins; Squalene; Triterpenes; Dammaranes
PubMed: 29993074
DOI: 10.1039/c8np00029h -
Journal of Microbiology and... Mar 2016Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically,... (Review)
Review
Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically, squalene is used not only as a precursor in the synthesis of complex secondary metabolites such as sterols, hormones, and vitamins, but also as a carbon source in aerobic and anaerobic fermentation in microorganisms. Owing to the increasing roles of squalene as an antioxidant, anticancer, and anti-inflammatory agent, the demand for this chemical is highly urgent. As a result, with the exception of traditional methods of the isolation of squalene from animals (shark liver oil) and plants, biotechnological methods using microorganisms as producers have afforded increased yield and productivity, but a reduction in progress. In this paper, we first review the biosynthetic routes of squalene and its typical derivatives, particularly the squalene synthase route. Second, typical biotechnological methods for the enhanced production of squalene using microbial cell factories are summarized and classified. Finally, the outline and discussion of the novel trend in the production of squalene with several updated events to 2015 are presented.
Topics: Bacteria; Biosynthetic Pathways; Fungi; Industrial Microbiology; Squalene
PubMed: 26643964
DOI: 10.4014/jmb.1510.10039 -
Applied and Environmental Microbiology Jun 2011Hopanoids and sterols are members of a large group of cyclic triterpenoic compounds that have important functions in many prokaryotic and eukaryotic organisms. They are... (Review)
Review
Hopanoids and sterols are members of a large group of cyclic triterpenoic compounds that have important functions in many prokaryotic and eukaryotic organisms. They are biochemically synthesized from linear precursors (squalene, 2,3-oxidosqualene) in only one enzymatic step that is catalyzed by squalene-hopene cyclase (SHC) or oxidosqualene cyclase (OSC). SHCs and OSCs are related in amino acid sequences and probably are derived from a common ancestor. The SHC reaction requires the formation of five ring structures, 13 covalent bonds, and nine stereo centers and therefore is one of the most complex one-step enzymatic reactions. We summarize the knowledge of the properties of triterpene cyclases and details of the reaction mechanism of Alicyclobacillus acidocaldarius SHC. Properties of other SHCs are included.
Topics: Alicyclobacillus; Evolution, Molecular; Intramolecular Transferases; Sequence Homology, Amino Acid; Squalene; Triterpenes
PubMed: 21531832
DOI: 10.1128/AEM.00300-11 -
International Journal of Environmental... Oct 2022(1) Background: The aim of the conducted research was to analyze the squalene content in infants' food. (2) Methods: The experimental material included human milk...
(1) Background: The aim of the conducted research was to analyze the squalene content in infants' food. (2) Methods: The experimental material included human milk collected from 100 women from Poland and three different infant formulas. The breast milk fat was extracted according to the Rose-Gottlieb method (AOAC), while the squalene content was determined using the high-performance liquid chromatography (HPLC) method. (3) Results: The highest amount of squalene was identified in the milk of women aged 18-25 ( < 0.05), and its content in milk decreased with the age of lactating women. Moreover, the greatest amount of squalene was identified in milk from the first lactation period (colostrum), while in mature milk, its content was more than two times lower. There was a correlation between breastfeeding BMI and the squalene content in milk (r = 0.78). (4) Conclusions: The conducted research shows that the level of squalene in human milk depends on physiological factors such as the lactation period and individual factors (age, BMI). The results of the conducted research indicate that breast milk is richer in squalene than modified milk. This study shows the importance of breastfeeding and indicates the superiority of breast milk over infant formulas.
Topics: Adolescent; Adult; Breast Feeding; Colostrum; Female; Humans; Infant; Infant Formula; Lactation; Milk, Human; Pregnancy; Squalene; Young Adult
PubMed: 36232224
DOI: 10.3390/ijerph191912928 -
World Journal of Microbiology &... Apr 2022Squalene is a triterpene hydrocarbon, a biochemical precursor for all steroids in plants and animals. It is a principal component of human surface lipids, in particular... (Review)
Review
Squalene is a triterpene hydrocarbon, a biochemical precursor for all steroids in plants and animals. It is a principal component of human surface lipids, in particular of sebum. Squalene has several applications in the food, pharmaceutical, and medical sectors. It is essentially used as a dietary supplement, vaccine adjuvant, moisturizer, cardio-protective agent, anti-tumor agent and natural antioxidant. With the increased demand for squalene along with regulations on shark-derived squalene, there is a need to find alternatives for squalene production which are low-cost as well as sustainable. Microbial platforms are being considered as a potential option to meet such challenges. Considerable progress has been made using both wild-type and engineered microbial strains for improved productivity and yields of squalene. Native strains for squalene production are usually limited by low growth rates and lesser titers. Metabolic engineering, which is a rational strain engineering tool, has enabled the development of microbial strains such as Saccharomyces cerevisiae and Yarrowia lipolytica, to overproduce the squalene in high titers. This review focuses on key strain engineering strategies involving both in-silico and in-vitro techniques. Emphasis is made on gene manipulations for improved precursor pool, enzyme modifications, cofactor regeneration, up-regulation of limiting reactions, and downregulation of competing reactions during squalene production. Process strategies and challenges related to both upstream and downstream during mass cultivation are detailed.
Topics: Animals; Metabolic Engineering; Saccharomyces cerevisiae; Squalene; Yarrowia
PubMed: 35426523
DOI: 10.1007/s11274-022-03273-w -
Proceedings of the National Academy of... Dec 2022Carotenoids are isoprenoid lipids found across the tree of life with important implications in oxidative stress adaptations, photosynthetic metabolisms, as well as in...
Carotenoids are isoprenoid lipids found across the tree of life with important implications in oxidative stress adaptations, photosynthetic metabolisms, as well as in membrane dynamics. The canonical view is that C40 carotenoids are synthesized from phytoene and C30 carotenoids from diapophytoene. Squalene is mostly associated with the biosynthesis of polycyclic triterpenes, although there have been suggestions that it could also be involved in the biosynthesis of C30 carotenoids. However, demonstration of the existence of this pathway in nature is lacking. Here, we demonstrate that C30 carotenoids are synthesized from squalene in the Planctomycetes bacteria and that this squalene route to C30 carotenoids is the most widespread in prokaryotes. Using the evolutionary history of carotenoid and squalene amino oxidases, we propose an evolutionary scenario to explain the origin and diversification of the different carotenoid and squalene-related pathways. We show that carotenoid biosynthetic pathways have been constantly transferred and neofunctionalized during prokaryotic evolution. One possible origin of the squalene pathway connects it with the one of C40 carotenoid synthesis of Cyanobacteria. The widespread occurrence of the squalene route to C30 carotenoids in increases the functional repertoire of squalene, establishing it as a general hub of carotenoids and polycyclic triterpenes synthesis.
Topics: Squalene; Biosynthetic Pathways; Carotenoids; Cyanobacteria; Triterpenes
PubMed: 36534808
DOI: 10.1073/pnas.2210081119 -
Communications Biology Nov 2023Recent findings have shown that fatty acid metabolism is profoundly involved in ferroptosis. However, the role of cholesterol in this process remains incompletely...
Recent findings have shown that fatty acid metabolism is profoundly involved in ferroptosis. However, the role of cholesterol in this process remains incompletely understood. In this work, we show that modulating cholesterol levels changes vulnerability of cells to ferroptosis. Cholesterol alters metabolic flux of the mevalonate pathway by promoting Squalene Epoxidase (SQLE) degradation, a rate limiting step in cholesterol biosynthesis, thereby increasing both CoQ10 and squalene levels. Importantly, whereas inactivation of Farnesyl-Diphosphate Farnesyltransferase 1 (FDFT1), the branch point of cholesterol biosynthesis pathway, exhibits minimal effect on ferroptosis, simultaneous inhibition of both CoQ10 and squalene biosynthesis completely abrogates the effect of cholesterol. Mouse models of ischemia-reperfusion and doxorubicin induced hepatoxicity confirm the protective role of cholesterol in ferroptosis. Our study elucidates a potential role of ferroptosis in diseases related to dysregulation of cholesterol metabolism and suggests a possible therapeutic target that involves ferroptotic cell death.
Topics: Mice; Animals; Squalene; Ubiquinone; Ferroptosis; Cholesterol
PubMed: 37914914
DOI: 10.1038/s42003-023-05477-8