Sterculic Acid: The Mechanisms of Action beyond Stearoyl-CoA Desaturase Inhibition and Therapeutic Opportunities in Human Diseases

MUFA synthesis and stearoyl-CoA desaturase as a new pharmacological target for modulation of lipid and alpha-synuclein interaction against Parkinson's disease synucleinopathy

Protein pathology spreading within the nervous system, accompanies neurodegeneration and a spectrum of motor and cognitive dysfunctions. Currently available therapies against Parkinson's disease and other synucleinopathies are mostly symptomatic and fail to slow the disease progression in the long term. Modification of α-synuclein (αS) aggregation and toxicity of its pathogenic forms is one of the main goals in neuroprotective approach. Since the discovery of lipid component of Lewy bodies, fatty acids became a crucial, yet little explored target for research. MUFAs (monounsaturated fatty acids) are substrates for lipids, such as phospholipids, triglycerides and cholesteryl esters. They regulate membrane fluidity, take part in signal transduction, cellular differentiation and other fundamental processes. αS and MUFA interactions are essential for Lewy body pathology. αS increases levels of MUFAs, mainly oleic acid, which in turn can enhance αS toxicity and aggregation. Thus, reduction of MUFAs synthesis by inhibition of stearoyl-CoA desaturase (SCD) activity could be the new way to prevent aggravation of αS pathology. Due to the limited distribution in peripheral tissues, SCD5 is a potential target in novel therapies and therefore could be an important starting point in search for disease-modifying neuroprotective therapy. Here we summarize facts about physiology and pathology of αS, explain recently discovered lipid-αS interactions, review SCD function and involved mechanisms, present available SCD inhibitors and discuss their pharmacological potential in disease management. Modulation of MUFA synthesis, decreasing αS and lipid toxicity is clearly essential, but unexplored avenue in pharmacotherapy of Parkinson's disease and synucleinopathies.

Has-miR-199a-3p/RELA/SCD inhibits immune checkpoints in AMD and promotes macrophage-mediated inflammation and pathological angiogenesis through lipid metabolism pathway: A computational analysis

More and more evidence shows that abnormal lipid metabolism leads to immune system dysfunction in AMD and promotes the occurrence of AMD by changing the homeostasis of ocular inflammation. However, the molecular mechanism underlying the effect of lipid metabolism on the phenotype and function of macrophages is still unclear, and the mechanism of association between AMD and cancer and COVID-19 has not been reported. The purpose of this study is to explore the interaction between lipid metabolism related genes, ferroptosis related genes and immunity in AMD, find out the key genes that affect the ferroptosis of AMD through lipid metabolism pathway and the molecular mechanism that mediates the action of macrophages, and find out the possible mechanism of lipid metabolism and potential co-therapeutic targets between AMD and cancer and COVID-19, so as to improve treatment decision-making and clinical results. For the first time, we have comprehensively analyzed the fatty acid molecule related genes, ferroptosis related genes and immune microenvironment of AMD patients, and determined that mast cells and M1 macrophages are the main causes of AMD inflammation, and found that SCD is the core gene in AMD that inhibits ferroptosis through lipid metabolism pathway, and verified the difference in the expression of SCD in AMD in a separate external data set. Based on the analysis of the mechanism of action of the SCD gene, we found for the first time that Has-miR-199a-3p/RELA/SCD is the core axis of action of lipid metabolism pathway to inhibit the ferroptosis of AMD. By inhibiting the immune checkpoint, we can enhance the immune cell activity of AMD and lead to the transformation of macrophages from M2 to M1, thereby promoting the inflammation and pathological angiogenesis of AMD. At the same time, we found that ACOX2 and PECR, as genes for fatty acid metabolism, may regulate the expression of SCD during the occurrence and development of COVID-19, thus affecting the occurrence and development of AMD. We found that FASD1 may be a key gene for the joint action of AMD and COVID-19, and SCD regulates the immune infiltration of macrophages in glioma and germ line tumors. In conclusion, our results can provide theoretical basis for the pathogenesis of AMD, help guide the treatment of AMD patients and their potentially related diseases and help to design effective drug targets.

Stearoyl-CoA desaturase 1 inhibition induces ER stress-mediated apoptosis in ovarian cancer cells

Ovarian cancer is a leading cause of death among gynecologic tumors, often detected at advanced stages. Metabolic reprogramming and increased lipid biosynthesis are key factors driving cancer cell growth. Stearoyl-CoA desaturase 1 (SCD1) is a crucial enzyme involved in de novo lipid synthesis, producing mono-unsaturated fatty acids (MUFAs). Here, we aimed to investigate the expression and significance of SCD1 in epithelial ovarian cancer (EOC). Comparative analysis of normal ovarian surface epithelial (NOSE) tissues and cell lines revealed elevated SCD1 expression in EOC tissues and cells. Inhibition of SCD1 significantly reduced the proliferation of EOC cells and patient-derived organoids and induced apoptotic cell death. Interestingly, SCD1 inhibition did not affect the viability of non-cancer cells, indicating selective cytotoxicity against EOC cells. SCD1 inhibition on EOC cells induced endoplasmic reticulum (ER) stress by activating the unfolded protein response (UPR) sensors and resulted in apoptosis. The addition of exogenous oleic acid, a product of SCD1, rescued EOC cells from ER stress-mediated apoptosis induced by SCD1 inhibition, underscoring the importance of lipid desaturation for cancer cell survival. Taken together, our findings suggest that the inhibition of SCD1 is a promising biomarker as well as a novel therapeutic target for ovarian cancer by regulating ER stress and inducing cancer cell apoptosis.

Targeting dihydroceramide desaturase 1 (Des1): Syntheses of ceramide analogues with a rigid scaffold, inhibitory assays, and AlphaFold2-assisted structural insights reveal cyclopropenone PR280 as a potent inhibitor

Dihydroceramide desaturase 1 (Des1) catalyzes the formation of a CC double bond in dihydroceramide to furnish ceramide. Inhibition of Des1 is related to cell cycle arrest and programmed cell death. The lack of the Des1 crystalline structure, as well as that of a close homologue, hampers the detailed understanding of its inhibition mechanism and difficults the design of new inhibitors, thus making Des1 a strategic target. Based on previous structure-activity studies, different ceramides containing rigid scaffolds were designed. The synthesis and evaluation of these compounds as Des1 inhibitors allowed the identification of PR280 as a better Des 1 inhibitor in vitro (IC50 = 700 nM) than GT11 and XM462, the current reference inhibitors. This cyclopropenone ceramide was obtained in a 6-step synthesis with a 24 % overall yield. The highly confident 3D structure of Des1, recently predicted by AlphaFold2, served as the basis for conducting docking studies of known Des1 inhibitors and the ceramide derivatives synthesized by us in this study. For this purpose, a complete holoprotein structure was previously constructed. This study has allowed a better knowledge of key ligand-enzyme interactions for Des1 inhibitory activity. Furthermore, it sheds some light on the inhibition mechanism of GT11.

Targeting Fatty Acid Desaturase I Inhibits Renal Cancer Growth Via ATF3-mediated ER Stress Response

Monounsaturated fatty acids (MUFAs) play a pivotal role in maintaining endoplasmic reticulum (ER) homeostasis, an emerging hallmark of cancer. However, the role of polyunsaturated fatty acid (PUFAs) desaturation in persistent ER stress driven by oncogenic abnormalities remains elusive. Fatty Acid Desaturase 1 (FADS1) is a rate-limiting enzyme controlling the bioproduction of long-chain PUFAs. Our previous research has demonstrated the significant role of FADS1 in cancer survival, especially in kidney cancers. We explored the underlying mechanism in this study. We found that pharmacological inhibition or knockdown of the expression of FADS1 effectively inhibits renal cancer cell proliferation and induces cell cycle arrest. The stable knockdown of FADS1 also significantly inhibits tumor formation in vivo. Mechanistically, we show that while FADS1 inhibition induces ER stress, its expression is also augmented by ER-stress inducers. Notably, FADS1-inhibition sensitized cellular response to ER stress inducers, providing evidence of FADS1's role in modulating the ER stress response in cancer cells. We show that, while FADS1 inhibition-induced ER stress leads to activation of ATF3, ATF3-knockdown rescues the FADS1 inhibition-induced ER stress and cell growth suppression. In addition, FADS1 inhibition results in the impaired biosynthesis of nucleotides and decreases the level of UPD-N-Acetylglucosamine, a critical mediator of the unfolded protein response. Our findings suggest that PUFA desaturation is crucial for rescuing cancer cells from persistent ER stress, supporting FADS1 as a new therapeutic target.

In vitro antitumor effects of aqueous extract and protease inhibitors from Sterculia striata st. Hil. et naud and metabolite profiling

The present study aims to assess the cytotoxic effect of the aqueous and protease inhibitors extracts of Sterculia striata on breast cancer cell lines. The in vitro results showed significant reductions in the highest concentrations from the S. striata seed extract for all cell lines. The aqueous extract reduced the viability by up to 35% in the MCF-7, 25% in the 4T1, and 35% in the MDA-MB-231 cell lines. Regarding the protease inhibitor extract, a 50% reduction in cell viability was observed in the MDA-MB-231 at concentration of 333 µg/mL. The aqueous and the protease inhibitor extracts showed mild reduction in the viability of macrophage cell lines. Chemical characterisation analysis revealed several polyphenols such as flavonoids, tannins, phenolic acids, and other secondary metabolites including terpenes, steroids, fatty acids, and organic acids, which may be related to the promising bioactivity observed. The S. striata showed antitumor activity, emphasising its pharmacological potential.

The Potential of Roselle (Hibiscus sabdariffa) Plant in Industrial Applications: A Promising Source of Functional Compounds

Roselle is an annual botanical plant that widely planted in different countries worldwide. Its different parts, including seeds, leaves, and calyces, can offer multi-purpose applications with economic importance. The present review discusses the detailed profile of bioactive compounds present in roselle seeds, leaves, and calyces, as well as their extraction and processing, to explore their potential application in pharmaceutical, cosmetic, nutraceutical, food and other industries. Roselle seeds with high phenolics, fiber, and protein contents, which are suitable to use in functional food product development. Besides, roselle seeds can yield 17-20% of roselle seed oil with high content of linoleic acid (35.0-45.3%) and oleic acid (27.1- 36.9%). This unique fatty acid composition of roselle seed oil makes it suitable to use as edible oil to offer the health benefits of essential fatty acid. Moreover, high contents of tocopherols, phenolics, and phytosterols were detected in roselle seed oil to provide nutritional, pharmaceutical, and therapeutic properties. On the other hand, roselle leaves with valuable contents of phenols, flavonoids, organic acid, and tocopherols can be applied in silver nanoparticles, food product development, and the pharmaceutical industry. Roselle calyces with high content of anthocyanins, protocatechuic acids, and organic acids are widely applied in food and colorant industries.

Targeting 7KCh-Induced Cell Death Response Mediated by p38, P2X7 and GSDME in Retinal Pigment Epithelium Cells with Sterculic Acid

Age-related macular degeneration (AMD) is the main cause of blindness in developed countries. AMD is characterized by the formation of drusen, which are lipidic deposits, between retinal pigment epithelium (RPE) and the choroid. One of the main molecules accumulated in drusen is 7-Ketocholesterol (7KCh), an oxidized-cholesterol derivative. It is known that 7KCh induces inflammatory and cytotoxic responses in different cell types and the study of its mechanism of action is interesting in order to understand the development of AMD. Sterculic acid (SA) counteracts 7KCh response in RPE cells and could represent an alternative to improve currently used AMD treatments, which are not efficient enough. In the present study, we determine that 7KCh induces a complex cell death signaling characterized by the activation of necrosis and an alternative pyroptosis mediated by P2X7, p38 and GSDME, a new mechanism not yet related to the response to 7KCh until now. On the other hand, SA treatment can successfully attenuate the activation of both necrosis and pyroptosis, highlighting its therapeutic potential for the treatment of AMD.

BACE1 and SCD1 are associated with neurodegeneration

Introduction

Proteolytic processing of amyloid protein precursor by β-site secretase enzyme (BACE1) is dependent on the cellular lipid composition and is affected by endomembrane trafficking in dementia and Alzheimer's disease (AD). Stearoyl-CoA desaturase 1 (SCD1) is responsible for the synthesis of fatty acid monounsaturation (MUFAs), whose accumulation is strongly associated with cognitive dysfunction.

Methods

In this study, we analyzed the relationship between BACE1 and SCD1 in vivo and in vitro neurodegenerative models and their association in familial AD (FAD), sporadic AD (SAD), and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) using microscopy, biochemical, and mass SPECT approach.

Results

Our findings showed that BACE1 and SCD1 immunoreactivities were increased and colocalized in astrocytes of the hippocampus in a rat model of global cerebral ischemia (2-VO). A synergistic effect of double BACE1/SCD1 silencing on the recovery of motor and cognitive functions was obtained. This neuroprotective regulation involved the segregation of phospholipids (PLs) associated with polyunsaturated fatty acids in the hippocampus, cerebrospinal fluid, and serum. The double silencing in the sham and ischemic groups was stronger in the serum, inducing an inverse ratio between total phosphatydilcholine (PC) and lysophosphatidylcholine (LPC), represented mainly by the reduction of PC 38:4 and PC 36:4 and an increase in LPC 16:0 and LPC 18:0. Furthermore, PC 38:4 and PC:36:4 levels augmented in pathological conditions in in vitro AD models. BACE1 and SCD1 increases were confirmed in the hippocampus of FAD, SAD, and CADASIL.

Conclusion

Therefore, the findings suggest a novel convergence of BACE-1 and SCD1 in neurodegeneration, related to pro-inflammatory phospholipids.

Stearoyl coenzyme A desaturase-1: multitasker in cancer, metabolism, and ferroptosis

Cancer progression is a highly balanced process and is maintained by a sequence of finely tuned metabolic pathways. Stearoyl coenzyme A desaturase-1 (SCD1), the fatty enzyme that converts saturated fatty acids into monounsaturated fatty acids, is a critical modulator of the fatty acid metabolic pathway. SCD1 expression is associated with poor prognosis in several cancer types. SCD1 triggers an iron-dependent cell death called ferroptosis and elevated levels of SCD1 protect cancer cells against ferroptosis. Pharmacological inhibition of SCD1 as monotherapy and in combination with chemotherapeutic agents shows promising antitumor potential in preclinical models. In this review, we summarize the role of SCD in cancer cell progression, survival, and ferroptosis and discuss potential strategies to exploit SCD1 inhibition in future clinical trials.

Identification of 7-Ketocholesterol-Modulated Pathways and Sterculic Acid Protective Effect in Retinal Pigmented Epithelium Cells by Using Genome-Wide Transcriptomic Analysis

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. AMD is characterized by the formation of lipidic deposits between the retinal pigment epithelium (RPE) and the choroid called drusen. 7-Ketocholesterol (7KCh), an oxidized-cholesterol derivative, is closely related to AMD as it is one of the main molecules accumulated in drusen. 7KCh induces inflammatory and cytotoxic responses in different cell types, and a better knowledge of the signaling pathways involved in its response would provide a new perspective on the molecular mechanisms that lead to the development of AMD. Furthermore, currently used therapies for AMD are not efficient enough. Sterculic acid (SA) attenuates the 7KCh response in RPE cells and is presented as an alternative to improve these therapies. By using genome-wide transcriptomic analysis in monkey RPE cells, we have provided new insight into 7KCh-induced signaling in RPE cells, as well as the protective capacity of SA. 7KCh modulates the expression of several genes associated with lipid metabolism, endoplasmic reticulum stress, inflammation and cell death and induces a complex response in RPE cells. The addition of SA successfully attenuates the deleterious effect of 7KCh and highlights its potential for the treatment of AMD.

SCD1 deficiency exacerbates osteoarthritis by inducing ferroptosis in chondrocytes

Background

Osteoarthritis (OA) is a severe joint disease that causes cartilage destruction and mobility loss. Abnormal fatty acid metabolism of chondrocytes plays a role in OA development. Stearoyl-CoA desaturase (SCD1) is a rate-limiting enzyme in the anabolism of unsaturated fatty acids. This study aimed to investigate the role of the SCD1 protein in the degenerative process of OA.

Methods

The GSE176199 gene expression profile dataset was analyzed by Gene Set Enrichment Analysis (GSEA). An animal model of OA was established using C57BL/6J wild-type (WT) (n=40) and SCD1 knockout (SCD1-KO) (n=20) mice. The histological scoring method of the Osteoarthritis Research Society International (OARSI) was used to quantify the degree of cartilage degeneration. The expression of SCD1 protein and relevant ferroptosis indicators were evaluated.

Results

The GSEA analysis showed that unsaturated fatty acid synthesis was inhibited in human OA chondrocytes. Meanwhile, the expression of SCD1 protein was significantly reduced in human OA articular cartilage. SCD1-KO mice exhibited early OA and accelerated cartilage loss after destabilization of medial meniscus (DMM)-induced OA. Furthermore, we found that the SCD1-PPARG axis regulates articular cartilage homeostasis via a mechanism involving the induction of ferroptosis-related gene expression in ATDC5 chondrocytes.

Conclusions

SCD1 deficiency exacerbates OA by inducing ferroptosis in chondrocytes.

Crosstalk between fatty acid metabolism and tumour-associated macrophages in cancer progression

Over the last few decades, cancer has been regarded as an independent and self sustaining progression. The earliest hallmarks of cancer comprise of sustaining proliferative signalling, avoiding growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Nonetheless, two emerging hallmarks are being described: aberrant metabolic pathways and evasion of immune destruction. Changes in tumour cell metabolism are not restricted to tumour cells alone; the products of the altered metabolism have a direct impact on the activity of immune cells inside the tumour microenvironment, particularly tumour-associated macrophages (TAMs). The complicated process of cancer growth is orchestrated by metabolic changes dictating the tight mutual connection between these cells. Here, we discuss approaches to exploit the interaction of cancer cells' abnormal metabolic activity and TAMs. We also describe ways to exploit it by reprogramming fatty acid metabolism via TAMs.

Adrenoceptors and SCD1 in adipocytes/adipose tissues: The expression and variation in health and obesity

Obesity, considered a metabolic disorder, is one of the most significant health issues that the community has to cope with today. A rising number of studies have been conducted to find out promising genetic targets for obese treatment. The sympathetic nervous system was proven to possess remarkable roles in energy metabolism, including the stimulation of lipolysis as well as thermogenesis, via distinct adrenoceptors appearing on the membrane of adipocyte. A decrease of β-adrenoceptor expression has been observed in obese individuals, which is related to reducing energy expenditure and developing obesity. While that the deficiency of stearoyl-CoA desaturase-1 (SCD1), which is a promising target for treatments of metabolic diseases, decreases oxidation and promotes the synthesis of fatty acids. Here, we emphasized several differences between distinct adrenoceptor subtypes, including their mRNA expression level and function in white adipose tissue and brown adipose tissue. We also highlighted SCD1's roles related to the progression of adipocytes and its changing expression under the obese condition in both rodents and humans, and furthermore, tried to figure out the interaction between adrenoceptors and SCD1 in adipose tissue.

Pretreatment of human retinal pigment epithelial cells with sterculic acid forestalls fenretinide-induced apoptosis

The ratio of saturated to monounsaturated fatty acids, thought to play a critical role in many cellular functions, is regulated by stearoyl-CoA desaturase (SCD), a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids. Previously, we observed a decrease in both SCD protein and enzymatic activity in apoptosis induced by fenretinide, a synthetic analog of retinoic acid, in the human retinal pigment epithelial (RPE) cell line ARPE-19. Here, we investigated the effect of pretreating ARPE-19 with sterculic acid, a cyclopropenoic fatty acid inhibitor of SCD, on preventing fenretinide-induced apoptosis, given the role of SCD in cell proliferation and apoptosis. We show that sterculic acid pretreatment prevents the effects of fenretinide-induced apoptosis shown by changes in cell morphology, viability, and caspase-3 activation. Analysis of endoplasmic reticulum (ER)-associated proteins shows that sterculic acid pretreatment reduced the fenretinide-induced upregulation of heme oxygenase-1, ATF3 and GADD153 expression that are in response to reactive oxygen species (ROS) generation. Sterculic acid is as effective as allopurinol in inhibition of xanthine oxidase (XDH), and this may play a role in reducing the potential role of XDH in fenretinide-induced ROS generation. Sterculic acid pretreatment also results in a reduction in SOD2 mRNA expression. Dihydroceramide accumulation, compared to ceramide, and ROS generation indicate that a ceramide-independent pathway mediates fenretinide-induced apoptosis, and ROS mediation is borne out by activation of the NF-κBp50 and NF-κBp65 downstream signaling cascade. Its prevention by sterculic acid pretreatment further indicates the latter's antioxidant/anti-inflammatory effect. Taken together, our results suggest that sterculic acid pretreatment can mitigate ROS-mediated fenretinide-induced apoptosis. Thus, sterculic acid may serve as a potential antioxidant and therapeutic agent. These effects may be independent of its effects on SCD activity.

Pharmacological and Nutraceutical Activation of Rejuvenation, Geroprotection and Cytoprotection: Proofs of Concept

Aging is a process associated with life [...].

Live-Cell Imaging of Sterculic Acid-a Naturally Occurring 1,2-Cyclopropene Fatty Acid-by Bioorthogonal Reaction with Turn-On Tetrazine-Fluorophore Conjugates

In the field of lipid research, bioorthogonal chemistry has made the study of lipid uptake and processing in living systems possible, whilst minimising biological properties arising from detectable pendant groups. To allow the study of unsaturated free fatty acids in live cells, we here report the use of sterculic acid, a 1,2-cyclopropene-containing oleic acid analogue, as a bioorthogonal probe. We show that this lipid can be readily taken up by dendritic cells without toxic side effects, and that it can subsequently be visualised using an inverse electron-demand Diels-Alder reaction with quenched tetrazine-fluorophore conjugates. In addition, the lipid can be used to identify changes in protein oleoylation after immune cell activation. Finally, this reaction can be integrated into a multiplexed bioorthogonal reaction workflow by combining it with two sequential copper-catalysed Huisgen ligation reactions. This allows for the study of multiple biomolecules in the cell simultaneously by multimodal confocal imaging.

Critical Review on Fatty Acid-Based Food and Nutraceuticals as Supporting Therapy in Cancer

Fatty acids have an important place in both biological and nutritional contexts and, from a clinical point of view, they have known consequences for diseases’ onset and development, including cancer. The use of fatty acid-based food and nutraceuticals to support cancer therapy is a multidisciplinary subject, involving molecular and clinical research. Knowledge regarding polyunsaturated fatty acids essentiality/oxidizability and the role of lipogenesis-desaturase pathways for cell growth, as well as oxidative reactivity in cancer cells, are discussed, since they can drive the choice of fatty acids using their multiple roles to support antitumoral drug activity. The central role of membrane fatty acid composition is highlighted for the application of membrane lipid therapy. As fatty acids are also known as biomarkers of cancer onset and progression, the personalization of the fatty acid-based therapy is also possible, taking into account other important factors such as formulation, bioavailability and the distribution of the supplementation. A holistic approach emerges combining nutra- and pharma-strategies in an appropriate manner, to develop further knowledge and applications in cancer therapy.

Blockage of NDUFB9-SCD1 pathway inhibits adipogenesis : Blockage of NDUFB9-SCD1 pathway inhibits adipogenesis

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with an increasing global prevalence associated with tremendous clinical, economic, and health-related quality-of-life burden. Currently, no effective pharmacological therapy is available for NAFLD. Adipogenesis process is accompanied by fat synthesis which may participate in the occurrence and development of NAFLD. Despite intensive investigations, numerous mechanistic aspects of adipogenesis remain unclear and many potential therapeutic targets are yet to be discovered.In this study, the transcriptomics and lipidomics approaches were used to explore the functional genes regulating adipogenesis and the potential mechanism in OP9 cells and adipose-derived stem cells.We find that NADH:ubiquinone oxidoreductase subunit b9 (Ndufb9) is up-regulated in adipogenesis (p < 0.001), and silencing Ndufb9 (83% silencing efficiency) inhibits adipogenesis. The effect of Ndufb9 is mediated through stearoyl-CoA desaturase 1 (Scd1). Aramchol, a SCD1 inhibitor, significantly blocks adipogenesis (markedly TG decrease, p < 0.001).Our study broadens the understanding of the role of Ndufb9 in adipogenesis and provides a new target for the treatment of NAFLD.

Ndufa6 regulates adipogenic differentiation via Scd1

Obesity and associated complications are becoming a pandemic. Inhibiting adipogenesis is an important intervention for the treatment of obesity. Despite intensive investigations, numerous mechanistic aspects of adipogenesis remain unclear, and many potential therapeutic targets have yet to be discovered. Transcriptomics and lipidomics approaches were used to explore the functional genes regulating adipogenic differentiation and the potential mechanism in OP9 cells and adipose-derived stem cells. In this study, we found that NADH:ubiquinone oxidoreductase subunit A6 (Ndufa6) participates in the regulation of adipogenic differentiation. Furthermore, we show that the effect of Ndufa6 is mediated through stearoyl-CoA desaturase 1 (Scd1) and demonstrate the inhibitory effect of a SCD1 inhibitor on adipogenesis. Our study broadens the understanding of adipogenic differentiation and offers NDUFA6-SCD1 as a potential therapeutic target for the treatment of obesity.

Sterculic Acid Alters Adhesion Molecules Expression and Extracellular Matrix Compounds to Regulate Migration of Lung Cancer Cells

Sterculic acid (SA) is a cyclopropenoid fatty acid isolated from Sterculia foetida seeds. This molecule is a well-known inhibitor of SCD1 enzyme, also known as ∆9-desaturase, which main function is related to lipid metabolism. However, recent studies have demonstrated that it also modifies many other pathways and the underlying gene expression. SCD overexpression, or up-regulated activity, has been associated with tumor aggressiveness and poor prognosis in many cancer types. Scd1 down-regulation, with different inhibitors or molecular strategies, reduces tumor cell survival and cell proliferation, as well as the chemoresistance associated with cancer stem cell presence. However, SA effects over cancer cell migration and extracellular matrix or adhesion molecules have not been described in cancer cells up to now. We used different migration assays and qPCR gene expression analysis to evaluate the effects of SA treatment in cancer cells. The results reveal that SA induces tumoral cell death at high doses, but we also observed that lower SA-treatments induce cell adhesion-migration capacity reduction as a result of modifications in the expression of genes related to integrins and extracellular matrix compounds. Overall, the functional and transcriptomic findings suggest that SA could represent a new inhibitor activity of epithelial to mesenchymal transition.

Effect of CLA supplementation on factors related to vascular dysfunction in arteries of orchidectomized rats

The vascular endothelium is a monolayer of flat epithelial cells located between the circulating blood and the underlying connective tissue. It conveys key functions that when impaired, lead to endothelial dysfunction. This condition is responsible for the pathogenesis of vascular diseases. The cardioprotective effect of sex hormones is widely known; hence, a murine orchidectomized model has been employed to study the effects caused by their deficiency. In the search for approaches to maintain vascular health, the effect of dietary fatty acids as CLA on cardiovascular diseases has been studied. Some proven beneficial properties of CLA are antioxidant, antiatherogenic and anti-inflammatory. Our objective was to evaluate the effect of a diet supplemented with 1.8 % (w/w) of CLA, administered during eight weeks, on the amount of cholesterol oxidation products (COPs) produced by orchidectomy and on factors related to vascular dysfunction in the aorta and the mesenteric arteries. The diet with CLA prevented the increase in prostanoids formation and maintained the normal physiological conditions of NO and antioxidant activity. In addition, it prevented the increase in cholesterol and COPs at the vascular wall. CLA-supplemented diet prevented the orchidectomy-induced alterations on prostanoids, NO and COPs and also improved the antioxidant activity. These findings could contribute to understand the mechanisms of actions of CLA involved in the prevention of cardiovascular diseases.

Inhibition of Stearoyl-CoA Desaturase by Sterculic Oil Reduces Proliferation and Induces Apoptosis in Prostate Cancer Cell Lines

Prostate cancer (PCa) is a common type of cancer affecting male population. PCa treatments have side effects and are temporarily effective, so new therapeutic options are being investigated. Due to the high demand of energy for cell proliferation, an increase in the expression and activity of lipogenic enzymes such as the stearoyl-CoA desaturase (SCD) have been observed in PCa. Sterculic acid, contained in the seed's oil of Malvales, is a natural inhibitor of SCD. The objective of our investigation was to evaluate the effects of sterculic oil (SO) from Sterculia apetala seeds on proliferation, cell cycle and apoptosis in prostate cancer cells. SO was administered to PC3 and LNCaP cells, and to prostate normal cells; cell viability, cell cycle, apoptosis, SCD gene and protein expression and enzymatic activity were analyzed. SO administration (4 mM sterculic acid) diminished cell viability in LNCaP and PC3 cells, arrested cell cycle in G2 and promoted apoptosis. SO diminished SCD enzymatic activity with no effects on gene nor protein expression. Our results suggest that SO might offer benefits as an adjuvant in hormonal and chemotherapy prostate cancer treatments. This is the first study to analyze the effect of SO on cancer cells.

Neuronal mitochondrial dysfunction in a cellular model of circadian rhythm disruption is rescued by donepezil

Human circadian rhythm refers to the intrinsic ∼24-h oscillation that regulates biological processes to adapt to environments. Disruption of rhythmicity causes mitochondrial dysfunction, changes metabolism, and is associated with neurodegenerative diseases and mental disorders. By employing cellular respiration analyses and mitochondrial membrane potential characterization, we confirmed that donepezil, a sigma-1 receptor agonist, restored mitochondrial function in neuronal cells with induced-circadian rhythm disruption (CRD). This protective effect was elicited by boosting oxidative respiration and increasing mitochondrial membrane potentials. Furthermore, donepezil treatment reinstated rhythmicity of core clock genes. Our findings suggest a novel countermeasure for treating CRD-related neurodegeneration and mental disorders.

Tilia sp. Seed Oil—Composition, Antioxidant Activity and Potential Use

Research on new, untapped seed oil sources is receiving increased attention. In this study, 18 different seed samples of Tilia cordata and Tilia platyphyllos from various locations in Slovenia were collected and oil was extracted. The compositions of triglyceride fatty acids and unsaponifiable compounds were determined using GC-MS, while antioxidant activity was evaluated using the DPPH method. The oil content in the seeds varied significantly, from 9.1% to 21.7%. Linoleic acid (50–60%) was found to be the predominant fatty acid, followed by oleic acid (18–22%) and palmitic acid (8–9%). Characteristic cyclopropene fatty acids (sterculic, dihydrosterculic and malvalic acids) were present in the average range of 4–8.4%. Antioxidant activity ranged from 8.9% to 65.5%, and was higher, on average, for T. platyphyllos. Higher antioxidant activity was closely correlated with higher γ-tocopherol contents. Statistically significant correlations were confirmed between antioxidant activity and γ-tocopherol, between Δ-tocopherol and phytol, between stigmasterol and β-sitosterol and between squalene and malvalic acid. Tilia oil may be of great interest for cosmetic and dermal preparations. It is, however, not considered a good source of dietary fatty acids due to the undesired, significant content of omega-6 fatty acids.

Anopheles coluzzii stearoyl-CoA desaturase is essential for adult female survival and reproduction upon blood feeding

Vitellogenesis and oocyte maturation require anautogenous female Anopheles mosquitoes to obtain a bloodmeal from a vertebrate host. The bloodmeal is rich in proteins that are readily broken down into amino acids in the midgut lumen and absorbed by the midgut epithelial cells where they are converted into lipids and then transported to other tissues including ovaries. The stearoyl-CoA desaturase (SCD) plays a pivotal role in this process by converting saturated (SFAs) to unsaturated (UFAs) fatty acids; the latter being essential for maintaining cell membrane fluidity amongst other housekeeping functions. Here, we report the functional and phenotypic characterization of SCD1 in the malaria vector mosquito Anopheles coluzzii. We show that RNA interference (RNAi) silencing of SCD1 and administration of sterculic acid (SA), a small molecule inhibitor of SCD1, significantly impact on the survival and reproduction of female mosquitoes following blood feeding. Microscopic observations reveal that the mosquito thorax is quickly filled with blood, a phenomenon likely caused by the collapse of midgut epithelial cell membranes, and that epithelial cells are depleted of lipid droplets and oocytes fail to mature. Transcriptional profiling shows that genes involved in protein, lipid and carbohydrate metabolism and immunity-related genes are the most affected by SCD1 knock down (KD) in blood-fed mosquitoes. Metabolic profiling reveals that these mosquitoes exhibit increased amounts of saturated fatty acids and TCA cycle intermediates, highlighting the biochemical framework by which the SCD1 KD phenotype manifests as a result of a detrimental metabolic syndrome. Accumulation of SFAs is also the likely cause of the potent immune response observed in the absence of infection, which resembles an auto-inflammatory condition. These data provide insights into mosquito bloodmeal metabolism and lipid homeostasis and could inform efforts to develop novel interventions against mosquito-borne diseases.

Female mosquitoes can become infected with malaria parasites upon ingestion of blood from an infected person and can transmit the disease when they bite another person some days later. The bloodmeal is rich in proteins which female mosquitoes use to develop their eggs after converting them first to saturated and then to unsaturated fatty acids inside their gut cells. Here, we present the characterization of the enzyme that mosquitoes use to convert saturated to unsaturated fatty acids and show that when this enzyme is eliminated or inhibited mosquitoes cannot produce eggs and die soon after they feed on blood. The mosquito death appears to be primarily associated with the collapse of their gut epithelial barrier due to the loss of cell membrane integrity, leading to their inner body cavity being filled with the ingested blood. These mosquitoes also suffer from an acute and detrimental auto-inflammatory condition due to mounting of a potent immune response in the absence of any infection. We conclude that this enzyme and the mechanism of converting blood-derived proteins to unsaturated fatty acids as a whole can be a good target of interventions aiming at limiting the mosquito abundance and blocking malaria transmission.

circRNA-miRNA-mRNA network in age-related macular degeneration: From construction to identification

The aim of the present study was to investigate the pathogenesis of age-related macular degeneration (AMD) by constructing a regulatory circRNA-miRNA-mRNA network. By adjusting the P value to <0.05 and the absolute log value of fold change to >0.25, 2920 and 1057 differentially expressed mRNAs were identified from GSE50195 and GSE29801, respectively. Based on a literature review, Starbase database analysis, and RNA hybrid assays, we obtained 77 miRNA-mRNA and 331 circRNA-miRNA pairs. After combining these pairs, we constructed a circRNA-miRNA-mRNA network possessing 303 circRNA nodes, 4 miRNA nodes, 51 mRNA nodes, and 408 edges. By utilizing protein-protein network analysis, the MCODE algorithm, and the highest degree of circRNA node, we identified the regulatory axis of hsa_circRNA7329/hsa-miR-9/SCD. Hsa_circRNA7329 may regulate SCD through hsa-miR-9 to promote macrophage-mediated inflammation and pathologic angiogenesis, which lead to AMD development. However, the underlying details require further investigation.

Effect of the dietary combination of flaxseed and Ricinodendron heudelotii or Punica granatum seed oil on the fatty acid profile of eggs

The health promoting omega-3, -7, and -5 fatty acids, α-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA), and α-eleostearic acid (α-ESA)/punicic acid (PunA), are not currently combined in frequently consumed food items. We have evaluated the impact of supplementing laying hens' feeds with flaxseeds combined with oil derived from seeds of either Ricinodendron heudelotii, an α-ESA source, or Punica granatum, a PunA source, on the egg fatty acid profile. The supplemented diets increased the egg content in ALA, DHA, RmA, as well as α-ESA or PunA. The combination of dietary lipids did not affect the conversion rate of ALA into DHA. Hens fed on R. heudelotii or P. granatum seed oil both accumulated RmA in egg yolk, indicating an efficient conversion from the α-ESA or PunA precursors through a Δ-13 reductase activity. The accumulation of PunA in eggs was largely higher than that of α-ESA.

Identification of Cyclopropane Fatty Acids in Human Plasma after Controlled Dietary Intake of Specific Foods

Cyclopropane fatty acids (CPFAs) are an investigated class of secondary fatty acids of microbial origin recently identified in foods. Even though the dietary daily intake of this class of compounds it has been recently estimated as not negligible, to date, no studies specifically have investigated their presence in human plasma after consumption of CPFA-rich sources. Therefore, the aims of this study were (i) to test CPFAs concentration in human plasma, thus demonstrating their in vivo bioaccessibility and potential bioavailability, (ii) to investigate a dose-response relationship between medium term chronic intake of CPFAs-rich foods and both CPFAs and plasma total fatty acid profiles in healthy subjects. Ten healthy normal weight adults were enrolled for conducting an in vivo study. Participants were asked to follow a CPFA-controlled diet for 3 weeks, consuming 50 g of Grana Padano cheese (GP) and 250 mL of whole cow milk, which correspond to a total of 22.1 mg of CPFAs. Fasting CPFAs concentration were monitored for eight timepoints during the whole study and plasma total fatty acids composition was determined by GC-MS. CPFAs, mainly dihydrosterculic acid (DHSA), were identified in plasma total fatty acids profile at the beginning of the study and after dietary treatment. A significant (p < 0.05) increase of CPFAs mean plasma concentration (n = 10) were observed at the end of the dietary intervention. Contrarily, the total fatty acids composition of the general plasma fatty acids profile did not significantly change (p ≥ 0.05) during the dietary intervention period. This is the first investigation demonstrating that CPFAs are bioaccessible in vivo and, as expected, their plasmatic concentration may be affected by consumption of CPFAs-rich foods. This research will open the door to further detailed research, which may better elucidate the role of these compounds in human health.

Adiantic acid, a new unsaturated fatty acid with a cyclopropane moiety from Adiantum flabellulatum L

Phytochemical investigation of Adiantum flabellulatum L. led to the isolation of four natural compounds, including a novel unsaturated fatty acid with a cyclopropane moiety, i.e. (S,E)-7-(2-octylcyclopropylidene)heptanoic acid (1), together with three known compounds, isoadiantol B (2), stigmast-4-en-6β-ol-3-one (3), β-sitosterol (4). Compound 3 was isolated from the A. flabellulatum L. for the first time. The structure of 1 was elucidated following a comprehensive analysis of spectroscopic analyses including MS, 1 D and 2 D NMR, and by a mass spectrometry experiment of the dimethyl disulfide (DMDS) adduct, while the known compounds were identified by comparisons with those reported in the literature. Enzyme evaluation of 1 indicated this compound possesses anti- protein tyrosine phosphatase (PTP1B) activity with an IC₅₀ value of 6.99 ± 0.41 μM in vitro.

Virtual screening of potentially endocrine-disrupting chemicals against nuclear receptors and its application to identify PPARγ-bound fatty acids

Nuclear receptors (NRs) are key regulators of energy homeostasis, body development, and sexual reproduction. Xenobiotics binding to NRs may disrupt natural hormonal systems and induce undesired adverse effects in the body. However, many chemicals of concerns have limited or no experimental data on their potential or lack-of-potential endocrine-disrupting effects. Here, we propose a virtual screening method based on molecular docking for predicting potential endocrine-disrupting chemicals (EDCs) that bind to NRs. For 12 NRs, we systematically analyzed how multiple crystal structures can be used to distinguish actives and inactives found in previous high-throughput experiments. Our method is based on (i) consensus docking scores from multiple structures at a single functional state (agonist-bound or antagonist-bound), (ii) multiple functional states (agonist-bound and antagonist-bound), and (iii) multiple pockets (orthosteric site and alternative sites) of these NRs. We found that the consensus enrichment from multiple structures is better than or comparable to the best enrichment from a single structure. The discriminating power of this consensus strategy was further enhanced by a chemical similarity-weighted scoring scheme, yielding better or comparable enrichment for all studied NRs. Applying this optimized method, we screened 252 fatty acids against peroxisome proliferator-activated receptor gamma (PPARγ) and successfully identified 3 previously unknown fatty acids with Kd = 100-250 μM including two furan fatty acids: furannonanoic acid (FNA) and furanundecanoic acid (FUA), and one cyclopropane fatty acid: phytomonic acid (PTA). These results suggested that the proposed method can be used to rapidly screen and prioritize potential EDCs for further experimental evaluations.

Fatty Acids and Membrane Lipidomics in Oncology: A Cross-Road of Nutritional, Signaling and Metabolic Pathways

Fatty acids are closely involved in lipid synthesis and metabolism in cancer. Their amount and composition are dependent on dietary supply and tumor microenviroment. Research in this subject highlighted the crucial event of membrane formation, which is regulated by the fatty acids' molecular properties. The growing understanding of the pathways that create the fatty acid pool needed for cell replication is the result of lipidomics studies, also envisaging novel fatty acid biosynthesis and fatty acid-mediated signaling. Fatty acid-driven mechanisms and biological effects in cancer onset, growth and metastasis have been elucidated, recognizing the importance of polyunsaturated molecules and the balance between omega-6 and omega-3 families. Saturated and monounsaturated fatty acids are biomarkers in several types of cancer, and their characterization in cell membranes and exosomes is under development for diagnostic purposes. Desaturase enzymatic activity with unprecedented de novo polyunsaturated fatty acid (PUFA) synthesis is considered the recent breakthrough in this scenario. Together with the link between obesity and cancer, fatty acids open interesting perspectives for biomarker discovery and nutritional strategies to control cancer, also in combination with therapies. All these subjects are described using an integrated approach taking into account biochemical, biological and analytical aspects, delineating innovations in cancer prevention, diagnostics and treatments.

Determination of Cyclopropenoid Fatty Acids in Ewe Milk Fat by GC-MS after Intravenous Administration of Sterculic Acid

Cyclopropenoid fatty acids (CPEFA), found in oilseeds from Malvaceae and Sterculiaceae, have been shown to interfere with the endogenous synthesis of several bioactive lipids of dairy fat, such as cis-9, trans-11 18:2 and cis-9 18:1, by inhibiting Δ9-desaturase. No previous study has reported the presence of sterculic acid in animal fat and its incorporation in tissues after its administration, due to the lack of a proper methodology. In the present research, a GC-MS method based on cold base derivatization to fatty acids methylesters was developed to determine CPEFA in ewe milk triglycerides, after infusing sterculic acid (0.5 g/day) to six lactating ewes. An alternative derivatization based on silanyzation followed by GC-MS analysis was also tested, showing its possible applicability when CPEFA are present in the form of free fatty acids. Sterculic acid was detected in ewe milk triglycerides, demonstrating its incorporation from the bloodstream into milk by the mammary gland. The mean transfer rate represented 8.0 ± 1.0% of the daily dose. This study provides, for the first time, the presence of sterculic acid in milk fat, supporting the importance of understanding its occurrence in vivo and encouraging further research to determine whether it can be present in foods, such as dairy products, obtained under practical farming conditions.

Genome-Wide Transcriptomic Analysis Identifies Pathways Regulated by Sterculic Acid in Retinal Pigmented Epithelium Cells

In addition to its predominant role in lipid metabolism and body weight control, SCD1 has emerged recently as a potential new target for the treatment of various diseases. Sterculic acid (SA) is a cyclopropene fatty acid with numerous biological activities, generally attributed to its Stearoyl-CoA desaturase (SCD) inhibitory properties. Additional effects exerted by SA, independently of SCD inhibition, may be mediating anti-inflammatory and protective roles in retinal diseases such as age-related macular degeneration (AMD), but the mechanisms involved are poorly understood. In order to provide insights into those mechanisms, genome-wide transcriptomic analyses were carried out in mRPE cells exposed to SA for 24 h. Integrative functional enrichment analysis of genome-wide expression data provided biological insight about the protective mechanisms induced by SA. On the one hand, pivotal genes related to fatty acid biosynthesis, steroid biosynthesis, cell death, actin-cytoskeleton reorganization and extracellular matrix-receptor interaction were significantly downregulated by exposition to SA. On the other hand, genes related to fatty acid degradation and beta-oxidation were significantly upregulated. In conclusion, SA administration to RPE cells regulates crucial pathways related to cell proliferation, inflammation and cell death that may be of interest for the treatment of ocular diseases.