Sustainable biosynthesis of squalene from waste cooking oil by the yeast Yarrowia lipolytica.

Squalene is a highly sought-after triterpene compound in growing demand, and its production offers a promising avenue for circular economy practices. In this study, we applied metabolic engineering principles to enhance squalene production in the nonconventional yeast Yarrowia lipolytica, using waste cooking oil as a substrate. By overexpressing key enzymes in the mevalonate pathway - specifically ERG9 encoding squalene synthase, ERG20 encoding farnesyl diphosphate synthase, and HMGR encoding hydroxy-methyl-glutaryl-CoA reductase - we achieved a yield of 779.9 mg/L of squalene. Further co-overexpression of DGA1, encoding diacylglycerol acyltransferase, and CAT2, encoding carnitine acetyltransferase, in combination with prior metabolic enhancements, boosted squalene production to 1381.4 mg/L in the engineered strain Po1g17. To enhance the supply of the precursor acetyl-CoA and inhibit downstream squalene conversion, we supplemented with 6 g/L pyruvic acid and 0.7 mg/L terbinafine, resulting in an overall squalene titer of 2594.1 mg/L. These advancements underscore the potential for sustainable, large-scale squalene production using Y. lipolytica cell factories, contributing to circular economy initiatives by valorizing waste materials.

[Cloning and functional characterization of oxidosqualene cyclase gene for α-amyrin synthesis].

Ursolic acid has gradually attracted much attention due to its unique pharmacological activities and valuable market value in recent years. Currently, ursolic acid is mostly extracted from loquat leaves, but the plant extraction method has low yield and high cost, and chemical synthesis is not readily available, so the biosynthesis method provides a new source for ursolic acid. α-amyrin acts as the main precursor for the synthesis of ursolic acid, and its yield is positively correlated with ursolic acid yield. Oxidosqualene cyclase(OSC) belongs to a multigene family which can catalyze the common precursor 2,3-oxidosqualene to generate different types of triterpene backbones, and plays a decisive role in the synthesis of triterpenoids. However, there are fewer reported key genes catalyzing the synthesis of α-amyrin in medicinal plants, and the yield and proportion of α-amyrin in the catalyzed products have always been a focus of research. In this study, ItOSC2, MdOSC1, AaOSC2 and CrAS, four enzymes capable of catalyzing the production of α-amyrin from 2,3-oxidosqualene, were cloned from Iris tectorum, Malus domestica, Artemisia annua and Catharanthus roseus, subject to sequence alignment and phylogenetic tree analyses, and transformed into Saccharomyces cerevisiae as plasmids. After 7 days of fermentation, the yield and proportions of α-amyrin, ß-amyrin and ergosterol were measured. Finally, AaOSC2 with the best ability to catalyze the generation of α-amyrin was filtered out, providing a key gene element for the later construction of engineered yeast strains with high production of α-amyrin and ursolic acid.

A nanomedicine approach for the treatment of long-lasting pain.

This study explores the potential of a nanomedicine approach, using Leu-enkephalin-squalene nanoparticles (LENK-SQ NPs) for managing long-lasting pain. It was observed that the nanomedicine significantly improved the pharmacological efficacy of the Leu-enkephalin, a fast metabolized neuropeptide, in a rat model of acute inflammatory pain, providing local analgesic effect, while minimizing potential systemic side effects by circumventing central nervous system. The LENK-SQ NPs were tested in a rat model of postoperative pain (Brennan's rodent plantar incision model) using continuous infusion via Alzet® pump, with an additional bolus injection. The analgesic activity was assessed through stimulus-evoked methods, such as the von Frey and Hargreaves tests. Both mechanical and thermal hyperalgesia were significantly reduced at days 2 and 3 post-incision. An additional pharmacokinetic study was conducted, showing that LENK-SQ NPs allowed a sustained circulation of the neuropeptide under its prodrug form. On the other hand, the biodistribution of fluorescently labelled LENK-SQ NPs revealed their selective accumulation in the incised paw within the first hour post administration, followed by a disassembly of the NPs, starting 24 h later. The study proposes the following multi-step mechanism for the anti-nociceptive pharmacological activity of LENK-SQ NPs: (i) protection of the neuropeptide from metabolization into the bloodstream, (ii) targeted accumulation of the nanoparticles within the incised painful tissue and (iii) gradual release of LENK at the onset of the inflammatory process, leading to the observed analgesic activity.

Potential emergence of terbinafine resistance by squalene epoxidase gene mutations: An 18-month cohort study of onychomycosis patients in the United States.

BACKGROUND: There is a concerning rise in antifungal-resistant dermatophytosis globally, with resistance to terbinafine conferred by point mutations in the squalene epoxidase (SQLE) gene. OBJECTIVES: Report changes in the prevalence and profile of SQLE mutations in onychomycosis patients in the United States. METHODS: A longitudinal cohort study of toenail samples was collected from suspected onychomycosis patients over an 18-month period from 2022 to 2023. Samples were submitted from across the United States and subjected to multiplex real-time polymerase chain reactions for dermatophyte detection, with further screening of SQLE mutations at four known hotspots (393Leu, 397Phe, 415Phe and 440His). RESULTS: A total of 62,056 samples were submitted (mean age: 57.5 years; female: 60.4%). Dermatophytes were detected in 38.5% of samples, primarily Trichophyton rubrum complex (83.6%) and T. mentagrophytes complex (10.7%). A survey of SQLE mutations was carried out in 22,610 dermatophyte samples; there was a significant increase in the prevalence of SQLE mutations between the first quarter of 2022 and the second quarter of 2023 (29.0 to 61.9 per 1000 persons). The Phe397Leu substitution was the predominant mutation; Phe415Ser and His440Tyr have also emerged which were previously reported as minor mutations in skin samples. The temporal change in mutation rates can be primarily attributed to the Phe415Ser substitution. Samples from elderly patients (>70 years) are more likely to be infected with the T. mentagrophytes complex including strains harbouring the Phe415Ser substitution. CONCLUSION: The prevalence of SQLE mutations among onychomycosis patients with Trichophyton infections may be underestimated. Older individuals may have a higher risk.

Kinetics of Squalene Quenching Singlet Oxygen and the Thermal Degradation Products Identification.

Squalene has been proven to possess various bioactive functions that are widely present in vegetable oils. A more comprehensive understanding of the reaction behavior of squalene under oxidative conditions was achieved by studying its antioxidant capacity and thermal degradation products. The total singlet oxygen quenching rate constant (kr + kq) of squalene was 3.8 × 107 M-1 s-1, and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by ß-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.

Amaranthus crop for food security and sustainable food systems.

MAIN CONCLUSION: This review ascertains amaranth grains as a potent crop for food security and sustainable food systems by highlighting its agricultural advantages, health benefits and applications in the food, packaging, and brewing industry. The global population surge and rapidly transitioning climatic conditions necessitate the maximization of nutritional crop yield to mitigate malnutrition resulting from food and nutrition insecurity. The modern agricultural practices adopted to maximize the yield of the conventional staple crops are heavily contingent on the depleting natural resources and are contributing extensively to the contamination of these natural resources. Furthermore, these agricultural practices are also causing detrimental effects on the environment like rising emission of greenhouse gasses and increased water footprints. To address these challenges while ensuring sustainable nutrient-rich crop production, it is imperative to utilize underutilized crops like Amaranthus. Amaranth grains are gluten-free pseudo-cereals that are gaining much prominence owing to their abundance in vital nutrients and bio-active components, potential health benefits, resilience to adverse climatic and soil conditions, minimum agricultural input requirements, potential of generating income for small holder farmers as well as various applications across the sustainable value chain. However, due to the limited awareness of these potential benefits of the amaranth grains among the consumers, researchers, and policymakers, they have remained untapped. This review paper enunciates the nutritional composition and potential health benefits of the grains while briefly discussing their various applications in food and beverage industries and accentuating the need to explore further possibilities of valorizing amaranth grains to maximize their utilization along the value chain.

Comparative Study of Camellia oleifera Seed Oil on Chemical Constituents, Antioxidant Activities and Physicochemical Characteristics from Southern China.

Eleven kinds of Camellia oleifera seed oils (CSOs) were evaluated in terms of chemical constituents, antioxidant activities, acid value (AV) as well as peroxide value (POV). These CSOs contained abundant ß-sitosterol, squalene, α-tocopherol and phenolics, in which the squalene was the distinct constituent with the content between 45.8±0.8 and 184.1±5.5 mg/kg. The ß-sitosterol ranging from 143.7±4.8 to 1704.6±72.0 mg/kg contributed a considerable content to total accompaniments. Palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid were present in these CSOs, in which the dominant fatty acid was oleic acid with the content between 59.66±0.72 and 82.89±2.16 g/100 g. The AV ranged from 0.1±0.0 to 1.3±0.0 mg KOH/g, and the POV was between 0.1±0.0 and 1.0±0.0 g/100 g. These CSOs showed antioxidant activity based on DPPH and ABTS radical scavenging assay. Both α-tocopherol and ß-sitosterol contents showed a positive correlation with DPPH and ABTS values, respectively, while the α-tocopherol content showed a negative correlation with AV. These results suggested that CSO can be categorized into high oleic acid vegetable oil with abundant active constituents, of which the quality presented variation among different origins. These accompaniments may contribute to the delay of its quality deterioration.

Increased terbinafine resistance among clinical genotypes of Trichophyton mentagrophytes/T. interdigitale species complex harboring squalene epoxidase gene mutations.

Terbinafine resistance has become epidemic as an emerging problem in treatment of dermatohpytosis. This could be attributed in part to a point mutation in the squalene epoxidase (SQLE) gene. In this study, point mutations in the SQLE gene were studied in T. rubrum and T. mentagrophytes/T. interdigitale species complex as two main causative agents of dermatophytosis. Antifungal susceptibility of clinical isolates of T. rubrum (n = 27) and T. mentagrophytes/T. interdigitale (n = 56) was assessed using the M38-3rd edition CLSI method. The SQLE gene and ITS region were sequenced for all the fungal strains, and the mutation sites and genotypes of the terbinafine-resistant strains were characterized. The results demonstrated that, in T. rubrum, the minimum inhibitory concentration of terbinafine (MIC50 and MIC90) was 0.03 µg/ml, and the geometric mean (G mean) concentration was 0.02. For the T. mentagrophytes complex, the MIC50 and MIC90 were 0.03 and 1.0 µg/ml, respectively, and the G mean concentration was 0.04 µg/ml. Four out of the five resistant strains were T. indotineae harboring the F397L and Q408L mutations, while the last one was T. mentagrophytes genotype VII, which harbors the F397L mutation. T. indotineae was the prominent causative agent of terbinafine resistance, with 80 % of the isolates, and T. mentagrophytes genotype VII was introduced as a new genotype in the terbinafine-resistant T. mentagrophytes complex. Our findings further substantiate the importance of antifungal susceptibility testing in selecting the choice of drug for effective treatment of dermatophytosis and highlight the importance of screening dermatophyte species for point mutations responsible for newly developed resistant strains to improve the current knowledge of overcoming infections caused by resistant species.

High Prevalence of Terbinafine Resistance Among Trichophyton mentagrophytes/T. interdigitale Species Complex, a Cross-Sectional Study from 2021 to 2022 in Northern Parts of Iran.

Treatment-resistant dermatophytosis caused by the members of the Trichophyton mentagrophytes/Trichophyton interdigitale species group (TMTISG) is increasing worldwide. We aimed to determine the prevalence of TMTISG in patients with dermatophytosis in two centers from north of Iran and detect the possible mutations in the squalene epoxidase (SQLE) gene in relevant terbinafine (TRB) resistant pathogenic isolates. From November 2021 to December 2022, 1960 patients suspected to dermatophytosis and referred to two mycology referral laboratories in the north of Iran were included in the study. Identification of all dermatophyte isolates was confirmed by RFLP of rDNA internal transcribed spacer (ITS) regions. Antifungal susceptibility testing against five common antifungals using the CLSI-M38-A3 protocol was performed. The TMTISG isolates resistant to TRB, were further analyzed to determine the possible mutations in the SQLE gene. Totally, 647 cases (33%) were positive for dermatophytosis of which 280 cases (43.3%) were identified as members of TMTISG. These were more frequently isolated from tinea corporis 131 (44.56%) and tinea cruris 116 (39.46%). Of 280 TMTISG isolates, 40 (14.3%) were resistant to TRB (MIC ≥ 4 µg/mL), all found to be T. indotineae in ITS sequencing. In SQLE sequencing 34 (85%) of TRB-resistant isolates had coincident mutations of Phe397Leu and Ala448Thr whereas four and two isolates had single mutations of Phe397Leu and Leu393Ser, respectively. Overall, the resistance of Iranian TMTISG isolates to TRB greatly occurred by a mutation of Phe397Leu in the SQLE gene as alone or in combination with Ala448Thr. Nevertheless, for the occurrence of in vitro resistance, only the presence of Phe397Leu mutation seems to be decisive.

A squalene analog 4,4'-diapophytofluene from coconut leaves having antioxidant and anti-senescence potentialities toward human fibroblasts and keratinocytes.

Coconut (Cocos nucifera) leaves, an unutilized resource, enriched with valuable bioactive compounds. Spectral analysis of purified pentane fraction of coconut leaves revealed the presence of a squalene analog named 4,4'-diapophytofluene or in short 4,4'-DPE (C30H46). Pure squalene standard (PSQ) showed cytotoxicity after 8 µg/ml concentration whereas 4,4'-DPE exhibited no cytotoxic effects up to 16 µg/ml concentration. On senescence-induced WI38 cells, 4,4'-DPE displayed better percentage of cell viability (164.5% at 24 h, 159.4% at 48 h and 148% at 72 h) compared to PSQ and BSQ (bio-source squalene) with same time duration. Similar trend of result was found in HaCaT cells. SA-ß-gal assay showed that number of ß-galactosidase positive cells were significantly decreased in senescent cells (WI38 and HaCaT) after treated with 4,4'-DPE than PSQ, BSQ. Percentage of ROS was increased to 60% in WI38 cells after olaparib treatment. When PSQ, BSQ and 4,4'-DPE were applied separately on these oxidative-stress-induced cells for 48 h, the overall percentage of ROS was decreased to 39.3%, 45.6% and 19.3% respectively. This 4,4'-DPE was found to be more effective in inhibiting senescence by removing ROS as compared to squalene. Therefore, this 4,4'-DPE would be new potent senotherapeutic agent for pharmaceuticals and dermatological products.

Phytochemical property and antimicrobial activity of Ficifolius A. Rich root extract: Advancing Ethiopian indigenous wart curing medicinal plant.

Although there may be a number of disadvantages, many patients prefer the traditional medication over surgical wart therapy since it may permanently remove the abscess from the body. The roots of the Ficifolius A. Rich plant are one of the native plants used in Ethiopia for traditional wart treatment. Therefore, the main goal of the research was to examine the phytochemical characteristics, identify the chemical compounds, and assess the antimicrobial effectiveness of the previously described plant root extract against gram-positive Staphylococcus aureus and gram-negative Escherichia coli pathogenic bacteria. Consequently, phytochemical characteristics such as tannins, alkaloids, flavonoids, phenols, and saponin were perceived, which inferred the therapeutic implications of root extracts. Furthermore, gas chromatography-mass spectrometry investigations identified a number of chemical components, including the particular antiviral substance Squalene. Moreover, antibacterial test results showed that the growth of gram-positive and gram-negative bacteria was inhibited with the application of crude extract. Generally, Ficifolius A. rich root extract could be effectively utilized for the treatment of anal warts.

Differential Regulation of DC Function, Adaptive Immunity, and MyD88 Dependence by MF59 and AS03-like Adjuvants.

MF59 and AS03 are squalene emulsion-based vaccine adjuvants with similar compositions and droplet sizes. Despite their broad use in licensed influenza vaccines, few studies compared their adjuvant effects and action mechanisms side by side. Considering the majority of adjuvants act on dendritic cells (DCs) to achieve their adjuvant effects, this study compared MF59 and AS03-like adjuvants (AddaVax and AddaS03, respectively) to enhance antigen uptake, DC maturation, ovalbumin (OVA) and seasonal influenza vaccine-induced immune responses. Considering MF59 was reported to activate MyD88 to mediate its adjuvant effects, this study also investigated whether the above-explored adjuvant effects of AddaVax and AddaS03 depended on MyD88. We found AddaVax more potently enhanced antigen uptake at the local injection site, while AddaS03 more potently enhanced antigen uptake in the draining lymph nodes. AddaS03 but not AddaVax stimulated DC maturation. Adjuvant-enhanced antigen uptake was MyD88 independent, while AddaS03-induced DC maturation was MyD88 dependent. AddaVax and AddaS03 similarly enhanced OVA-induced IgG and subtype IgG1 antibody responses as well as influenza vaccine-induced hemagglutination inhibition antibody titers, whileAddaS03 more potently enhanced OVA-specific IgG2c antibody responses. Both adjuvants depended on MyD88 to enhance vaccine-induced antibody responses, while AddaVax depended more on MyD88 to achieve its adjuvant effects. Our study reveals similarities and differences of the two squalene emulsion-based vaccine adjuvants, contributing to our improved understanding of their action mechanisms.

Biosynthesis of carotenoids in Azospirillum brasilense Cd is mediated via squalene (C30) route.

Azospirillum brasilense is a non-photosynthetic α-Proteobacteria, belongs to the family of Rhodospirillaceae and produces carotenoids to protect itself from photooxidative stress. In this study, we have used Resonance Raman Spectra to show similarity of bacterioruberins of Halobacterium salinarum to that of A. brasilense Cd. To navigate the role of genes involved in carotenoid biosynthesis, we used mutational analysis to inactivate putative genes predicted to be involved in carotenoid biosynthesis in A. brasilense Cd. We have shown that HpnCED enzymes are involved in the biosynthesis of squalene (C30), which is required for the synthesis of carotenoids in A. brasilense Cd. We also found that CrtI and CrtP desaturases were involved in the transformation of colorless squalene into the pink-pigmented carotenoids. This study elucidates role of some genes which constitute very pivotal role in biosynthetic pathway of carotenoid in A. brasilense Cd.

Depletion of squalene epoxidase in synergy with glutathione peroxidase 4 inhibitor RSL3 overcomes oxidative stress resistance in lung squamous cell carcinoma.

Background: Lung squamous cell carcinoma (LUSC) lacks effective targeted therapies and has a poor prognosis. Disruption of squalene epoxidase (SQLE) has been implicated in metabolic disorders and cancer. However, the role of SQLE as a monooxygenase involved in oxidative stress remains unclear. Methods: We analyzed the expression and prognosis of lung adenocarcinoma (LUAD) and LUSC samples from GEO and TCGA databases. The proliferative activity of the tumors after intervention of SQLE was verified by cell and animal experiments. JC-1 assay, flow cytometry, and Western blot were used to show changes in apoptosis after intervention of SQLE. Flow cytometry and fluorescence assay of ROS levels were used to indicate oxidative stress status. Results: We investigated the unique role of SQLE expression in the diagnosis and prognosis prediction of LUSC. Knockdown of SQLE or treatment with the SQLE inhibitor terbinafine can suppress the proliferation of LUSC cells by inducing apoptosis and reactive oxygen species accumulation. However, depletion of SQLE also results in the impairment of lipid peroxidation and ferroptosis resistance such as upregulation of glutathione peroxidase 4. Therefore, prevention of SQLE in synergy with glutathione peroxidase 4 inhibitor RSL3 effectively mitigates the proliferation and growth of LUSC. Conclusion: Our study indicates that the low expression of SQLE employs adaptive survival through regulating the balance of apoptosis and ferroptosis resistance. In future, the combinational therapy of targeting SQLE and ferroptosis could be a promising approach in treating LUSC.

Network pharmacology prediction and molecular docking-based strategy to explore the potential mechanism of squalene against inflammation.

Squalene (SQ) has been documented in the past for its ability to reduce inflammation, but its mechanism needs more information. In this study, we investigated squalene as an anti-inflammatory drug candidate and the framework involved in treating inflammation (INF) using the network pharmacology concept. The molecular targets of SQ and INF that are available in databases and the overlaps between these targets were demonstrated using InteractiVenn. The protein-protein networks were generated that in turn revealed several key targets and were further processed with Cytoscape. The gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) studies were performed. We also performed molecular docking tests that validated the binding affinity of molecular targets and drugs. A total of 100 SQ targets and 11,417 INF-related targets yielded 93 overlapping targets. Seven core targets, CRHR1, EGFR, ERBB2, HIF1A, SLC6A3, MAP2K1, and F2R were found to be relevant with respective to SQ's anti-inflammatory activity. The underlying mechanism of SQ with regard to INF was interpreted by analyzing various enrichment analyses along with the KEGG pathway. In conclusion, SQ played a vital role in the management of INF by regulating CRHR1, EGFR, ERBB2, HIF1A, SLC6A3, MAP2K1, and F2R. The research outcomes are crucial as they offer significant insights into the use of SQ for combating inflammation. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-024-00217-0.

Squalene epoxidase promotes the chemoresistance of colorectal cancer via (S)-2,3-epoxysqualene-activated NF-κB.

BACKGROUND: While de novo cholesterol biosynthesis plays a crucial role in chemotherapy resistance of colorectal cancer (CRC), the underlying molecular mechanism remains poorly understood. METHODS: We conducted cell proliferation assays on CRC cells with or without depletion of squalene epoxidase (SQLE), with or without 5-fluorouracil (5-FU) treatment. Additionally, a xenograft mouse model was utilized to explore the impact of SQLE on the chemosensitivity of CRC to 5-FU. RNA-sequencing analysis and immunoblotting analysis were performed to clarify the mechanism. We further explore the effect of SQLE depletion on the ubiquitin of NF-κB inhibitor alpha (IκBα) and (S)-2,3-epoxysqualene on the binding of IκBα to beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) by using immunoprecipitation assay. In addition, a cohort of 272 CRC patients were selected for our clinical analyses. RESULTS: Mechanistically, (S)-2,3-epoxysqualene promotes IκBα degradation and subsequent NF-κB activation by enhancing the interaction between BTRC and IκBα. Activated NF-κB upregulates the expression of baculoviral IAP repeat containing 3 (BIRC3), sustains tumor cell survival after 5-FU treatment and promotes 5-FU resistance of CRC in vivo. Notably, the treatment of terbinafine, an inhibitor of SQLE commonly used as antifungal drug in clinic, enhances the sensitivity of CRC to 5-FU in vivo. Additionally, the expression of SQLE is associated with the prognosis of human CRC patients with 5-FU-based chemotherapy. CONCLUSIONS: Thus, our finding not only demonstrates a new role of SQLE in chemoresistance of CRC, but also reveals a novel mechanism of (S)-2,3-epoxysqualene-dependent NF-κB activation, implicating the combined potential of terbinafine for 5-FU-based CRC treatment.

Soybean steroids improve crop abiotic stress tolerance and increase yield.

Sterols have long been associated with diverse fields, such as cancer treatment, drug development, and plant growth; however, their underlying mechanisms and functions remain enigmatic. Here, we unveil a critical role played by a GmNF-YC9-mediated CCAAT-box transcription complex in modulating the steroid metabolism pathway within soybeans. Specifically, this complex directly activates squalene monooxygenase (GmSQE1), which is a rate-limiting enzyme in steroid synthesis. Our findings demonstrate that overexpression of either GmNF-YC9 or GmSQE1 significantly enhances soybean stress tolerance, while the inhibition of SQE weakens this tolerance. Field experiments conducted over two seasons further reveal increased yields per plant in both GmNF-YC9 and GmSQE1 overexpressing plants under drought stress conditions. This enhanced stress tolerance is attributed to the reduction of abiotic stress-induced cell oxidative damage. Transcriptome and metabolome analyses shed light on the upregulation of multiple sterol compounds, including fucosterol and soyasaponin II, in GmNF-YC9 and GmSQE1 overexpressing soybean plants under stress conditions. Intriguingly, the application of soybean steroids, including fucosterol and soyasaponin II, significantly improves drought tolerance in soybean, wheat, foxtail millet, and maize. These findings underscore the pivotal role of soybean steroids in countering oxidative stress in plants and offer a new research strategy for enhancing crop stress tolerance and quality from gene regulation to chemical intervention.

In Silico Analysis of Selected Mikania Constituents As Human HMG-CoA Reductase, Human Inducible Nitric Oxide Synthase, and Human Squalene Synthase Inhibitory Agents.

Background Numerous pharmacological activities have been reportedin Mikania species. In the present investigation, we aimed to evaluate 26 selected constituents of Mikania as potent inhibitory agents of human HMG-CoA reductase (hHMGR), human inducible nitric oxide synthase (hiNOS), and human squalene synthase (hSQS) using the in silico method. Methodology Twenty-six selected constituents of Mikania were investigated based on the docking behavior of three target enzymes, namely hHMGR, hiNOS, and hSQS, using the Cdocker method (Discovery Studio® 3.1, Accelrys, Inc., San Diego, CA). Results Docking analysis showed that methyl-3,5-di-O-caffeoyl quinate (MCQ) has the maximum binding energy (BE) (-39.63, -50.65, and -58.56 kcal/mol) with hHMGR, hiNOS, and hSQS enzymes. On the other hand, six ligands (kaurenoic acid (KAA), stigmasterol (SS), grandifloric acid (GA), kaurenol (KA), spathlenol (SP), and taraxerol (TA)) of Mikania failed to dock with either of the target enzymes (hHMGR, hiNOS, or hSQS). Conclusions The findings of the current study provide new insight regarding 26 selected ligands of Mikania as potent inhibitory agents of hHMGR, hiNOS, and hSQS.

Remodeling the Homologous Recombination Mechanism of Yarrowia lipolytica for High-Level Biosynthesis of Squalene.

Squalene is a high-value antioxidant with many commercial applications. The use of microbial cell factories to produce squalene as an alternative to plant and animal extracts could meet increasing market demand. Yarrowia lipolytica is an excellent host for squalene production due to its high levels of acetyl-CoA and a hydrophobic environment. However, the need for precise and complicated gene editing has hindered the industrialization of this strain. Herein, the rapid construction of a strain with high squalene production was achieved by enhancing the homologous recombination efficiency in Y. lipolytica. First, remodeling of the homologous recombination efficiency resulted in a 10-fold increase in the homologous recombination rate. Next, the whole mevalonate pathway was integrated into the chromosome to enhance squalene production. Then, a higher level of squalene accumulation was achieved by increasing the level of acetyl coenzyme A and regulating the downstream steroid synthesis pathway. Finally, the squalene production reached 35 g/L after optimizing the fermentation conditions and performing a fed-batch culture in a 5 L jar fermenter. This is the highest squalene production ever reported to date by de novo biosynthesis without adding any inhibitors, paving a new path toward the industrial production of squalene and its downstream products.

Squalene-epoxidase-catalyzed 24(S),25-epoxycholesterol synthesis promotes trained-immunity-mediated antitumor activity.

The importance of trained immunity in antitumor immunity has been increasingly recognized, but the underlying metabolic regulation mechanisms remain incompletely understood. In this study, we find that squalene epoxidase (SQLE), a key enzyme in cholesterol synthesis, is required for ß-glucan-induced trained immunity in macrophages and ensuing antitumor activity. Unexpectedly, the shunt pathway, but not the classical cholesterol synthesis pathway, catalyzed by SQLE, is required for trained immunity induction. Specifically, 24(S),25-epoxycholesterol (24(S),25-EC), the shunt pathway metabolite, activates liver X receptor and increases chromatin accessibility to evoke innate immune memory. Meanwhile, SQLE-induced reactive oxygen species accumulation stabilizes hypoxia-inducible factor 1α protein for metabolic switching into glycolysis. Hence, our findings identify 24(S),25-EC as a key metabolite for trained immunity and provide important insights into how SQLE regulates trained-immunity-mediated antitumor activity.