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Xue J, Ye B, Sun M. Possible pathogenic mechanisms for doxorubicin-induced splenic atrophy in a human breast cancer xenograft mouse model. J Appl Toxicol 2024. [PMID: 38943348 DOI: 10.1002/jat.4666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/19/2024] [Accepted: 06/19/2024] [Indexed: 07/01/2024]
Abstract
Doxorubicin-based chemotherapy is a widely used first-line treatment for breast cancer, yet it is associated with various side effects, including splenic atrophy. However, the pathogenic mechanisms underlying doxorubicin-induced atrophy of the spleen remain unclear. This study investigates that doxorubicin treatment leads to splenic atrophy through several interconnected pathways involving histological changes, an inflammatory response, and apoptosis. Immunohistochemical and western blot analyses revealed reduced size of white and red pulp, decreased cellularity, amyloidosis, and fibrotic remodeling in the spleen following doxorubicin treatment. Additionally, increased secretion of pro-inflammatory cytokines was detected using an antibody array and enzyme-linked immunosorbent assay (ELISA), which triggers inflammation through the regulation of signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappa B (NF-κB) signaling pathways. Further analysis revealed that the loss of regulators and effectors of the oxidative defense system, including sirtuin (Sirt)3, Sirt5, superoxide dismutase (SOD)1, and SOD2, was implicated in the upstream regulation of caspase-dependent cellular apoptosis. These findings provide insights on the pathogenic mechanisms underlying doxorubicin-induced splenic atrophy and suggest that further investigation may be warranted to explore strategies for managing potential side effects in breast cancer patients treated with doxorubicin.
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Affiliation(s)
- Jianjie Xue
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao, China
- Qingdao Institute of Preventive Medicine, Qingdao, China
| | - Bing Ye
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao, China
- Qingdao Institute of Preventive Medicine, Qingdao, China
| | - Mengqi Sun
- College of Life Science, Changchun Sci-Tech University, Changchun, China
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2
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Craciun BF, Sandu IA, Peptanariu D, Pinteala M. Novel Nanotherapeutic Systems Based on PEGylated Squalene Micelles for Enhanced In Vitro Activity of Methotrexate and Cytarabine. Polymers (Basel) 2023; 15:4225. [PMID: 37959905 PMCID: PMC10650902 DOI: 10.3390/polym15214225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Nanomedicine has garnered significant attention due to the advantages it offers in the treatment of cancer-related disorders, some of the deadliest diseases affecting human lives. Conventional medication formulations often encounter issues of instability or insolubility in biological environments, resulting in low bioavailability. Nanocarriers play a crucial role in transporting and safeguarding drugs at specific sites of action, enabling gradual release under particular conditions. This study focuses on methotrexate (MTx) and cytarabine (Cyt), essential antitumoral drugs, loaded into PEGylated squalene micellar structures to enhance therapeutic effectiveness and minimize drawbacks. The micelles were prepared using ultrasound-assisted methods in both water and phosphate buffer saline solutions. Evaluation of drug-loaded micelles encompassed parameters such as particle size, colloidal stability, surface charge, morphology, encapsulation efficiency, drug loading capacity, and in vitro release profiles under simulated physiological and tumoral conditions. In vitro cell inhibition studies conducted on MCF-7 and HeLa cell lines demonstrated higher antitumoral activity for the drug-encapsulated micelles compared to free drugs. The encapsulation effectively addressed the burst effect, providing sustained release for at least 48 h while enhancing the drug's protection under physiological conditions.
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Affiliation(s)
- Bogdan-Florin Craciun
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (I.-A.S.); (D.P.)
| | | | | | - Mariana Pinteala
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (I.-A.S.); (D.P.)
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3
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Bioactive Compounds and Therapeutics from Fish: Revisiting Their Suitability in Functional Foods to Enhance Human Wellbeing. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3661866. [PMID: 36033572 PMCID: PMC9410824 DOI: 10.1155/2022/3661866] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/10/2022] [Indexed: 12/14/2022]
Abstract
Global public awareness about fish-based diet and its health/nutritional benefits is on the rise. Fish nutritional profile projects promising bioactive and other compounds with innumerable health benefits for human wellbeing. As various reported researches involving fish/marine-derived molecules reveal promising attributes, and as the position of fish-based nutrients as nutraceuticals continue to strengthen, health challenges still confront communities worldwide, from cardiovascular disease, diabetes, and obesity to hypertension. Thus, further understanding of fish-based nutrient impact as functional foods remains crucial given the diverse prevailing compositional/nutraceutical merits. In this review, therefore, we provide important information regarding bioactive compounds and therapeutics obtained from fish, specific to the context of their suitability in functional foods to enhance human health. This contribution is hereby constructed as follows: (a) fish nutraceutical/therapeutic components, (b) constituents of fish-based nutrients and their suitability in functional foods, (c) fish antioxidant/bioactive compounds to help alleviate health conditions, (d) common human ailments alleviated by fish-based nutrients, and (e) role of fish in mental health and immune system. As increased fish consumption should be encouraged, the potential of the quality proteins, omega-3 fatty acids, and other compounds inherent in fish should steadily be harnessed.
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Sisodiya S, Sinha A, Debnath M, Shekhawat R, Shekhawat SS. Protecting Superfood Olive Crop from Pests and Pathogens Using Image
Processing Techniques: A Review. CURRENT NUTRITION & FOOD SCIENCE 2022. [DOI: 10.2174/1573401318666211227103001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Olive (Oleo europaea L.) cultivars are widely cultivated all over the
world. However, they are often attacked by pests and pathogens. This deteriorates the quality of
the crop, leading to less yield of olive oil. The different infections that cause comparable disease
symptoms on olive leaves can be classified using image processing techniques.
Objective:
The olive has established itself as a superfood and a possible source of medicine, owing
to the rapid increase in the availability of data in the field of nutrigenomics. The goal of this
review is to underline the importance of applying image processing techniques to detect and
classify diseases early.
Method:
PubMed, ScienceDirect, and Google Scholar were used to conduct a systematic literature
search using the keywords olive oil, pest and pathogen of olives, and metabolic profiling.
Results:
Infections caused by infectious diseases frequently result in significant losses and lowquality
olive oil yields. Early detection of disease infestations can safeguard the olive plant and
its yield.
Results:
This strategy can help protect the crop from disease spread, and early detection and
classification of the disease can aid in prompt prophylaxis of diseased olive plants before the
disease worsens. Protecting olive plants from pests and pathogens can help keep the yield and
quality of olive oil consistent.
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Affiliation(s)
- Smita Sisodiya
- Department of Biosciences, Manipal University Jaipur, Jaipur, Rajasthan, India
| | - Aditya Sinha
- Department of Computer Science &
Engineering, Manipal University Jaipur, Jaipur, Rajasthan, India
| | - Mousumi Debnath
- Department of Biosciences, Manipal University Jaipur, Jaipur, Rajasthan, India
| | - Rajveer Shekhawat
- Department of Computer Science &
Engineering, Manipal University Jaipur, Jaipur, Rajasthan, India
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Assessment of adjuvantation strategy of lipid squalene nanoparticles for enhancing the immunogenicity of a SARS-CoV-2 spike subunit protein against COVID-19. Int J Pharm 2021; 607:121024. [PMID: 34416331 PMCID: PMC8372419 DOI: 10.1016/j.ijpharm.2021.121024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 11/24/2022]
Abstract
Vaccination is regarded as the most effective intervention for controlling the coronavirus disease 2019 (COVID-19) pandemic. The objective of this study is to provide comprehensive information on lipid squalene nanoparticle (SQ@NP)-adjuvanted COVID-19 vaccines regarding modulating immune response and enhancing vaccine efficacy. After being adjuvanted with SQ@NP, the SARS-CoV-2 spike (S) subunit protein was intramuscularly (i.m.) administered to mice. Serum samples investigated by ELISA and virus neutralizing assay showed that a single-dose SQ@NP-adjuvanted S-protein vaccine can induce antigen-specific IgG and protective antibodies comparable with those induced by two doses of nonadjuvanted protein vaccine. When the mice received a boosting vaccine injection, anamnestic response was observed in the groups of adjuvanted vaccine. Furthermore, the secretion of cytokines in splenocytes, such as interferon (IFN)-γ, interleukin (IL)-5 and IL-10, was significantly enhanced after adjuvantation of S-protein vaccine with SQ@NP; however, this was not the case for the vaccine adjuvanted with conventional aluminum mineral salts. Histological examination of injection sites showed that the SQ@NP-adjuvanted vaccine was considerably well tolerated following i.m. injection in mice. These results pave the way for the performance tuning of optimal vaccine formulations against COVID-19.
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The Impact of Short-Term Shark Liver Oil Supplementation on the Fatty Acid Composition of Erythrocyte Membranes. Nutrients 2021; 13:nu13103329. [PMID: 34684329 PMCID: PMC8540316 DOI: 10.3390/nu13103329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 02/06/2023] Open
Abstract
Fatty acid (FA) balance is strictly related to human health. The composition of fatty acids in lipid membranes seems to be influenced by diet. Shark liver oil (SLO) supplementation has been widely used recently in the prevention and treatment of human diseases. We analyzed the impact of short-term SLO supplementation on certain biochemical parameters and erythrocyte FA composition in a group of young healthy women. Our results showed that 6 weeks of SLO supplementation led to a significant decrease in C-reactive protein levels in sera and intracellular cholesterol levels in peripheral blood mononuclear cells. SLO supplementation caused a significant increase in the content of the polyunsaturated omega-3 FAs: docosahexaenoic acid, docosapentaenoic acid and α-linolenic acid. In the group of omega-6 FAs, we observed a significant elevation of arachidonic and dihomo-gamma-linoleic acid content. Due to these alterations, the omega-3 index increased significantly from 3.6% (before) to 4.2% (after supplementation). We also observed the impact of SLO supplementation on the membrane fluidity index. The ratio between saturated and unsaturated FAs decreased significantly from 13.1 to 9.9. In conclusion, our results show that even short-term SLO supplementation can improve human erythrocyte fatty acid composition and other parameters that may have health-promoting consequences.
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Liposomes Loaded with Unsaponifiable Matter from Amaranthus hypochondriacus as a Source of Squalene and Carrying Soybean Lunasin Inhibited Melanoma Cells. NANOMATERIALS 2021; 11:nano11081960. [PMID: 34443791 PMCID: PMC8397957 DOI: 10.3390/nano11081960] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 02/06/2023]
Abstract
Amaranthus hypochondriacus is a source of molecules with reported health benefits such as antioxidant activity and cancer prevention. The objective of this research was to optimize the conditions for preparing a liposome formulation using amaranth unsaponifiable matter as a source of squalene in order to minimize the particle size and to maximize the encapsulation efficiency of liposomes for carrying and delivering soybean lunasin into melanoma cell lines. Amaranth oil was extracted using supercritical dioxide carbon extraction (55.2 MPa pressure, 80 °C temperature, solvent (CO2)-to-feed (oil) ratio of 20). The extracted oil from amaranth was used to obtain the unsaponifiable enriched content of squalene, which was incorporated into liposomes. A Box–Behnken response surface methodology design was used to optimize the liposome formulation containing the unsaponifiable matter, once liposomes were optimized. Soybean lunasin was loaded into the liposomes and tested on A-375 and B16-F10 melanoma cells. The squalene concentration in the extracted oil was 36.64 ± 0.64 g/ 100 g of oil. The particle size in liposomes was between 115.8 and 163.1 nm; the squalene encapsulation efficiency ranged from 33.14% to 76.08%. The optimized liposome formulation contained 15.27 mg of phospholipids and 1.1 mg of unsaponifiable matter. Cell viability was affected by the liposome formulation with a half-maximum inhibitory concentration (IC50) equivalent to 225 μM in B16-F10 and 215 μM in A-375. The liposomes formulated with lunasin achieved 82.14 ± 3.34% lunasin encapsulation efficiency and improved efficacy by decreasing lunasin IC50 by 31.81% in B16-F10 and by 41.89% in A-375 compared with unencapsulated lunasin.
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Ho HM, Huang CY, Cheng YJ, Chen IH, Liu SJ, Huang CH, Huang MH. Squalene nanoemulsion reinforces mucosal and immunological fingerprints following intravaginal delivery. Biomed Pharmacother 2021; 141:111799. [PMID: 34098215 DOI: 10.1016/j.biopha.2021.111799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 01/03/2023] Open
Abstract
This study describes the assessment of mucosal adjuvant activity of a squalene-based nanoemulsion (SQ@NE) following intravaginal delivery in mice. After immunization, a high level of recruitment of CD11b/c+ granulocytes and F4/80+ macrophages was observed in the vaginal mucosal tissues of the mice immunized with a model protein ovalbumin (OVA) formulated with SQ@NE, and then downstream regulated the expression of MHC II and costimulatory molecules CD40 and CD86 on CD11c+ cells harvested from the associated draining lymph node. With respect to cytotoxic T lymphocyte immunity, the mice immunized with SQ@NE-formulated OVA elicited a high population of OVA-specific CD8+ cells in the spleen and increased the secretion of IFN-γ, IL-2 and IL-17 from OVA-restimulated splenocytes compared with those immunized with OVA alone. By studying in vivo fluorescence imaging and B-cell immunoassays, we discovered how SQ@NE prolongs the retention of antigen depots at the mucosal membrane of the immune inductive site and allows them to properly drive the production of antibodies. The data demonstrated that SQ@NE prolonged fluorescence-labeled OVA retention at the genital tract and augmented the production of OVA-specific IgG in sera and IgA in vaginal washes. These results indicate that SQ@NE is a promising vaginal adjuvant for the induction of both mucosal and systemic immune responses, a feature that provides implications for the development of a mucosal vaccine against genital infections and sexually transmitted diseases.
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Affiliation(s)
- Hui-Min Ho
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Chiung-Yi Huang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Yu-Jhen Cheng
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan
| | - I-Hua Chen
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Shih-Jen Liu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Chung-Hsiung Huang
- Department of Food Science, National Taiwan Ocean University, Keelung 20224, Taiwan.
| | - Ming-Hsi Huang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli 35053, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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Sasaki K, Geribaldi-Doldán N, Wu Q, Davies J, Szele FG, Isoda H. Microalgae Aurantiochytrium Sp. Increases Neurogenesis and Improves Spatial Learning and Memory in Senescence-Accelerated Mouse-Prone 8 Mice. Front Cell Dev Biol 2021; 8:600575. [PMID: 33634096 PMCID: PMC7900145 DOI: 10.3389/fcell.2020.600575] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/23/2020] [Indexed: 12/14/2022] Open
Abstract
Much attention has recently been focused on nutraceuticals, with minimal adverse effects, developed for preventing or treating neurological diseases such as Alzheimer's disease (AD). The present study was conducted to investigate the potential effect on neural development and function of the microalgae Aurantiochytrium sp. as a nutraceutical. To test neuroprotection by the ethanol extract of Aurantiochytrium (EEA) and a derivative, the n-Hexane layer of EEA (HEEA), amyloid-β-stimulated SH-SY5Y cells, was used as an in vitro AD model. We then assessed the potential enhancement of neurogenesis by EEA and HEEA using murine ex vivo neurospheres. We also administered EEA or HEEA to senescence-accelerated mouse-prone 8 (SAMP8) mice, a non-transgenic strain with accelerated aging and AD-like memory loss for evaluation of spatial learning and memory using the Morris water maze test. Finally, we performed immunohistochemical analysis for assessment of neurogenesis in mice administered EEA. Pretreatment of SH-SY5Y cells with EEA or the squalene-rich fraction of EEA, HEEA, ameliorated amyloid-β-induced cytotoxicity. Interestingly, only EEA-treated cells showed a significant increase in cell metabolism and intracellular adenosine triphosphate production. Moreover, EEA treatment significantly increased the number of neurospheres, whereas HEEA treatment significantly increased the number of β-III-tubulin+ young neurons and GFAP+ astrocytes. SAMP8 mice were given 50 mg/kg EEA or HEEA orally for 30 days. EEA and HEEA decreased escape latency in the Morris water maze in SAMP8 mice, indicating improved memory. To detect stem cells and newborn neurons, we administered BrdU for 9 days and measured BrdU+ cells in the dentate gyrus, a neurogenic stem cell niche of the hippocampus. In SAMP8 mice, EEA rapidly and significantly increased the number of BrdU+GFAP+ stem cells and their progeny, BrdU+NeuN+ mature neurons. In conclusion, our data in aggregate indicate that EEA and its constituents could be developed into a nutraceutical for promoting brain health and function against several age-related diseases, particularly AD.
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Affiliation(s)
- Kazunori Sasaki
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tsukuba, Japan
- Open Innovation Laboratory for Food and Medicinal Resource Engineering, National Institute of Advanced Industrial Science and Technology (AIST), University of Tsukuba, Tsukuba, Japan
- Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
| | - Noelia Geribaldi-Doldán
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tsukuba, Japan
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Qingqing Wu
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tsukuba, Japan
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Julie Davies
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Francis G. Szele
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Hiroko Isoda
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tsukuba, Japan
- Open Innovation Laboratory for Food and Medicinal Resource Engineering, National Institute of Advanced Industrial Science and Technology (AIST), University of Tsukuba, Tsukuba, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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Proshkina E, Plyusnin S, Babak T, Lashmanova E, Maganova F, Koval L, Platonova E, Shaposhnikov M, Moskalev A. Terpenoids as Potential Geroprotectors. Antioxidants (Basel) 2020; 9:antiox9060529. [PMID: 32560451 PMCID: PMC7346221 DOI: 10.3390/antiox9060529] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 02/07/2023] Open
Abstract
Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.
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Affiliation(s)
- Ekaterina Proshkina
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
| | - Sergey Plyusnin
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
- Pitirim Sorokin Syktyvkar State University, 55 Oktyabrsky Prosp., 167001 Syktyvkar, Russia
| | - Tatyana Babak
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
| | - Ekaterina Lashmanova
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
| | | | - Liubov Koval
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
- Pitirim Sorokin Syktyvkar State University, 55 Oktyabrsky Prosp., 167001 Syktyvkar, Russia
| | - Elena Platonova
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
- Pitirim Sorokin Syktyvkar State University, 55 Oktyabrsky Prosp., 167001 Syktyvkar, Russia
| | - Mikhail Shaposhnikov
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
| | - Alexey Moskalev
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russia; (E.P.); (S.P.); (T.B.); (E.L.); (L.K.); (E.P.); (M.S.)
- Pitirim Sorokin Syktyvkar State University, 55 Oktyabrsky Prosp., 167001 Syktyvkar, Russia
- Correspondence: ; Tel.: +7-8212-312-894
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A key mammalian cholesterol synthesis enzyme, squalene monooxygenase, is allosterically stabilized by its substrate. Proc Natl Acad Sci U S A 2020; 117:7150-7158. [PMID: 32170014 PMCID: PMC7132291 DOI: 10.1073/pnas.1915923117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cholesterol biosynthesis is a high-cost process and, therefore, tightly regulated by both transcriptional and posttranslational negative feedback mechanisms in response to the level of cellular cholesterol. Squalene monooxygenase (SM, also known as squalene epoxidase or SQLE) is a rate-limiting enzyme in the cholesterol biosynthetic pathway and catalyzes epoxidation of squalene. The stability of SM is negatively regulated by cholesterol via its N-terminal regulatory domain (SM-N100). In this study, using a SM-luciferase fusion reporter cell line, we performed a chemical genetics screen that identified inhibitors of SM itself as up-regulators of SM. This effect was mediated through the SM-N100 region, competed with cholesterol-accelerated degradation, and required the E3 ubiquitin ligase MARCH6. However, up-regulation was not observed with statins, well-established cholesterol biosynthesis inhibitors, and this pointed to the presence of another mechanism other than reduced cholesterol synthesis. Further analyses revealed that squalene accumulation upon treatment with the SM inhibitor was responsible for the up-regulatory effect. Using photoaffinity labeling, we demonstrated that squalene directly bound to the N100 region, thereby reducing interaction with and ubiquitination by MARCH6. Our findings suggest that SM senses squalene via its N100 domain to increase its metabolic capacity, highlighting squalene as a feedforward factor for the cholesterol biosynthetic pathway.
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