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The genome of Caenorhabditis elegans encodes 284 nuclear hormone receptor, which perform diverse functions in development and physiology. One of the best characterized of these is NHR-49, related in sequence and function to mammalian hepatocyte nuclear factor 4α and peroxisome proliferator-activated receptor α. Initially identified as regulator of lipid metabolism, including fatty acid catabolism and desaturation, additional important roles for NHR-49 have since emerged. It is an essential contributor to longevity in several genetic and environmental contexts, and also plays vital roles in the resistance to several stresses and innate immune response to infection with various bacterial pathogens. Here, we review how NHR-49 is integrated into pertinent signaling circuits and how it achieves its diverse functions. We also highlight areas for future investigation including identification of regulatory inputs that drive NHR-49 activity and identification of tissue-specific gene regulatory outputs. We anticipate that future work on this protein will provide information that could be useful for developing strategies to age-associated declines in health and age-related human diseases.

AbstractThe micronutrient vitamin B12 is an essential cofactor for two enzymes: methionine synthase, which plays a key role in the one-carbon cycle; and methylmalonyl-CoA mutase, an enzyme in a pathway that breaks down branched-chain amino acids and odd-chain fatty acids. A second, vitamin B12-independent pathway that degrades propionic acid was recently described in Caenorhabditis elegansC. elegansmdt-15C. elegans mdt-15mdt-15mdt-15nhr-10mdt-15mdt-15

Gut microbiota has been established as a main regulator of health. However, how changes in gut microbiota are directly associated with physiological and cellular alterations has been difficult to tackle on a large-scale basis, notably because of the cost and labor-extensive resources required for rigorous experiments in mammals. In the present study, we used the nematode Caenorhabditis elegans as a model organism to elucidate microbiota-host interactions. We developed a method to extract gut microbiota (MCB) from murine feces, and tested its potential as food source for and its impact on C. elegans biology compared to the standard bacterial diet Escherichia coli OP50. Although less preferred than OP50, MCB was not avoided but had a lower energy density (triglycerides and glucose). Consistently, MCB-fed worms exhibited smaller body length and size, lower fertility, and lower fat content than OP50-fed worms, but had a longer mean lifespan, which resembles the effects of calorie restriction in mammals. However, these outcomes were altered when bacteria were inactivated, suggesting an important role of symbiosis of MCB beyond nutrient source. Taken together, our findings support the effectiveness of gut MCB processing to test its effects in C. elegans. More work comparing MCB of differently treated mice or humans is required to further validate relevance to mammals before large-scale screening assays.

The response to insufficient oxygen (hypoxia) is orchestrated by the conserved hypoxia-inducible factor (HIF). However, HIF-independent hypoxia response pathways exist that act in parallel with HIF to mediate the physiological hypoxia response. Here, we describe a hypoxia response pathway controlled by Caenorhabditis elegans nuclear hormone receptor NHR-49, an orthologue of mammalian peroxisome proliferator-activated receptor alpha (PPARα). We show that nhr-49 is required for animal survival in hypoxia and is synthetic lethal with hif-1 in this context, demonstrating that these factors act in parallel. RNA-seq analysis shows that in hypoxia nhr-49 regulates a set of genes that are hif-1-independent, including autophagy genes that promote hypoxia survival. We further show that nuclear hormone receptor nhr-67 is a negative regulator and homeodomain-interacting protein kinase hpk-1 is a positive regulator of the NHR-49 pathway. Together, our experiments define a new, essential hypoxia response pathway that acts in parallel with the well-known HIF-mediated hypoxia response.

The model organism Caenorhabditis elegans mounts transcriptional defense responses against intestinal bacterial infections that elicit overlapping starvation and infection responses, the regulation of which is not well understood. Direct comparison of C. elegans that were starved or infected with Staphylococcus aureus revealed a large infection-specific transcriptional signature, which was almost completely abrogated by deletion of transcription factor hlh-30/TFEB, except for six genes including a flavin-containing monooxygenase (FMO) gene, fmo-2/FMO5. Deletion of fmo-2/FMO5 severely compromised infection survival, thus identifying the first FMO with innate immunity functions in animals. Moreover, fmo-2/FMO5 induction required the nuclear hormone receptor, NHR-49/PPAR-α, which controlled host defense cell non-autonomously. These findings reveal an infection-specific host response to S. aureus, identify HLH-30/TFEB as its main regulator, reveal FMOs as important innate immunity effectors in animals, and identify the mechanism of FMO regulation through NHR-49/PPAR-α during S. aureus infection, with implications for host defense and inflammation in higher organisms.

Zinc is essential for cellular functions as it is a catalytic and structural component of many proteins. In contrast, cadmium is not required in biological systems and is toxic. Zinc and cadmium levels are closely monitored and regulated as their excess causes cell stress. To maintain homeostasis, organisms induce metal detoxification gene programs through stress responsive transcriptional regulatory complexes. In Caenorhabditis elegans, the MDT-15 subunit of the evolutionarily conserved Mediator transcriptional coregulator is required to induce genes upon exposure to excess zinc and cadmium. However, the regulatory partners of MDT-15 in this response, its role in cellular and physiological stress adaptation, and the putative role for mammalian MED15 in the metal stress responses remain unknown. Here, we show that MDT-15 interacts physically and functionally with the Nuclear Hormone Receptor HIZR-1 to promote molecular, cellular, and organismal adaptation to cadmium and excess zinc. Using gain- and loss-of-function mutants and qRT-PCR and reporter analysis, we find that mdt-15 and hizr-1 cooperate to induce zinc and cadmium responsive genes. Moreover, the two proteins interact physically in yeast-two-hybrid assays and this interaction is enhanced by the addition of zinc or cadmium, the former a known ligand of HIZR-1. Functionally, mdt-15 and hizr-1 mutants show defective storage of excess zinc in the gut and are hypersensitive to zinc-induced reductions in egg-laying. Furthermore, mdt-15 but not hizr-1 mutants are hypersensitive to cadmium-induced reductions in egg-laying, suggesting potential divergence of regulatory pathways. Lastly, mammalian MDT-15 orthologs bind genomic regulatory regions of metallothionein and zinc transporter genes in a cadmium and zinc-stimulated fashion, and human MED15 is required to induce a metallothionein gene in lung adenocarcinoma cells exposed to cadmium. Collectively, our data show that mdt-15 and hizr-1 cooperate to regulate cadmium detoxification and zinc storage and that this mechanism is at least partially conserved in mammals.

Abstract Parkinson disease (PD) is the second most common neurodegenerative disorder and the leading neurodegenerative cause of motor disability. Pathologic accumulation of aggregated alpha synuclein (AS) protein in brain, and imbalance in the nigrostriatal system due to the loss of dopaminergic neurons in the substantia nigra- pars compacta, are hallmark features in PD. AS aggregation and propagation are considered to trigger neurotoxic mechanisms in PD, including mitochondrial deficits and oxidative stress. The eukaryotic elongation factor-2 kinase (eEF2K) mediates critical regulation of dendritic mRNA translation and is a crucial molecule in diverse forms of synaptic plasticity. Here we show that eEF2K activity, assessed by immuonohistochemical detection of eEF2 phosphorylation on serine residue 56, is increased in postmortem PD midbrain and hippocampus. Induction of aggressive, AS-related motor phenotypes in a transgenic PD M83 mouse model also increased brain eEF2K expression and activity. In cultures of dopaminergic N2A cells, overexpression of wild-type human AS or the A53T mutant increased eEF2K activity. eEF2K inhibition prevented the cytotoxicity associated with AS overexpression in N2A cells by improving mitochondrial function and reduced oxidative stress. Furthermore, genetic deletion of the eEF2K ortholog efk-1 in C. elegans attenuated human A53T AS induced defects in behavioural assays reliant on dopaminergic neuron function. These data suggest a role for eEF2K activity in AS toxicity, and support eEF2K inhibition as a potential target in reducing AS-induced oxidative stress in PD.

Despite many advances, the molecular links between energy metabolism and longevity are not well understood. Here, we have used the nematode model Caenorhabditis elegans to study the role of the yet-uncharacterized gene R148.3 in fat accumulation and lifespan. In wild-type worms, a R148.3p::GFP reporter showed enhanced expression throughout life in the pharynx, in neurons, and in muscles. Functionally, a protein fusing a predicted 22 amino acid N-terminal signal sequence (SS) of R148.3 to mCherry displayed robust accumulation in coelomyocytes, indicating that R148.3 is a secreted protein. Systematic depletion of R148.3 by RNA interference (RNAi) at L1 but not at young-adult stage enhanced triglyceride accumulation, which was associated with increased food uptake and lower expression of genes involved in lipid oxidation. However, RNAi of R148.3 at both L1 and young-adult stages robustly diminished mean and maximal lifespan of wild-type worms, and also abolished the long-lived phenotypes of eat-2 and daf-2/InsR mutants. Based on these data, we propose that R148.3 is an SS that modulates fat mass and longevity in an independent manner.

Low temperatures delay aging and promote longevity in many organisms. However, the metabolic and homeostatic aspects of low-temperature-induced longevity remain poorly understood. Here, we show that lipid homeostasis regulated by Caenorhabditis elegans Mediator 15 (MDT-15 or MED15), a transcriptional coregulator, is essential for low-temperature-induced longevity and proteostasis. We find that inhibition of mdt-15 prevents animals from living long at low temperatures. We show that MDT-15 up-regulates fat-7, a fatty acid desaturase that converts saturated fatty acids (SFAs) to unsaturated fatty acids (UFAs), at low temperatures. We then demonstrate that maintaining a high UFA/SFA ratio is essential for proteostasis at low temperatures. We show that dietary supplementation with a monounsaturated fatty acid, oleic acid (OA), substantially mitigates the short life span and proteotoxicity in mdt-15(-) animals at low temperatures. Thus, lipidostasis regulated by MDT-15 appears to be a limiting factor for proteostasis and longevity at low temperatures. Our findings highlight the crucial roles of lipid regulation in maintaining normal organismal physiology under different environmental conditions.

The ability to adapt to acute and chronic stress is important for organisms to thrive in evolutionary niches and for cells to survive in adverse conditions. The regulatory networks that control stress responses are evolutionarily conserved, and many factors that selectively activate stress responses have been identified. Less well understood are mechanisms that guard against unnecessary induction of cytoprotective factors and that connect stress responses with cellular metabolism to control energy expenditure during stress. The work of Riahi and colleagues represents important progress in this regard because it identifies the histone methyltransferase G9a as a modulator of oxidative stress responses. G9a dampens the expression of antioxidant genes, thus preventing inappropriate energy consumption. Moreover, G9a promotes the well-paced catabolism of storage glycogen and fat during stress. The importance of energy availability during stress is further evidenced by exogenous glucose rescuing the vulnerability of the G9a mutant to oxidative stress. Prior work in multiple model systems has implicated G9a in several other adaptive responses. Therefore, its role in pacing energy consumption and in restraining excessive stress response gene expression under stress may extend to other adaptive responses across species.

Biological membranes are not only essential barriers that separate cellular and subcellular structures, but also perform other critical functions such as the initiation and propagation of intra- and intercellular signals. Each membrane-delineated organelle has a tightly regulated and custom-made membrane lipid composition that is critical for its normal function. The endoplasmic reticulum (ER) consists of a dynamic membrane network that is required for the synthesis and modification of proteins and lipids. The accumulation of unfolded proteins in the ER lumen activates an adaptive stress response known as the unfolded protein response (UPR-ER). Interestingly, recent findings show that lipid perturbation is also a direct activator of the UPR-ER, independent of protein misfolding. Here, we review proteostasis-independent UPR-ER activation in the genetically tractable model organism Caenorhabditis elegans. We review the current knowledge on the membrane lipid composition of the ER, its impact on organelle function and UPR-ER activation, and its potential role in human metabolic diseases. Further, we summarize the bi-directional interplay between lipid metabolism and the UPR-ER. We discuss recent progress identifying the different respective mechanisms by which disturbed proteostasis and lipid bilayer stress activate the UPR-ER. Finally, we consider how genetic and metabolic disturbances may disrupt ER homeostasis and activate the UPR and discuss how using -omics-type analyses will lead to more comprehensive insights into these processes.

Nuclear hormone receptors (NHRs) are transcription factors that regulate numerous physiological and developmental processes and represent important drug targets. NHR-49, an ortholog of Hepatocyte Nuclear Factor 4 (HNF4), has emerged as a key regulator of lipid metabolism and life span in the nematode worm Caenorhabditis elegans. However, many aspects of NHR-49 function remain poorly understood, including whether and how it regulates individual sets of target genes and whether its activity is modulated by a ligand. A recent study identified three gain-of-function (gof) missense mutations in nhr-49 (nhr-49(et7), nhr-49(et8), and nhr-49(et13), respectively). These substitutions all affect the ligand-binding domain (LBD), which is critical for ligand binding and protein interactions. Thus, these alleles provide an opportunity to test how three specific residues contribute to NHR-49 dependent gene regulation. We used computational and molecular methods to delineate how these mutations alter NHR-49 activity. We find that despite originating from a screen favoring the activation of specific NHR-49 targets, all three gof alleles cause broad upregulation of NHR-49 regulated genes. Interestingly, nhr-49(et7) and nhr-49(et8) exclusively affect nhr-49 dependent activation, whereas the nhr-49(et13) surprisingly affects both nhr-49 mediated activation and repression, implicating the affected residue as dually important. We also observed phenotypic non-equivalence of these alleles, as they unexpectedly caused a long, short, and normal life span, respectively. Mechanistically, the gof substitutions altered neither protein interactions with the repressive partner NHR-66 and the coactivator MDT-15 nor the subcellular localization or expression of NHR-49. However, in silico structural modeling revealed that NHR-49 likely interacts with small molecule ligands and that the missense mutations might alter ligand binding, providing a possible explanation for increased NHR-49 activity. In sum, our findings indicate that the three nhr-49 gof alleles are non-equivalent, and highlight the conserved V411 residue affected by et13 as critical for gene activation and repression alike.

Magnetic resonance (MR) imaging of superparamagnetic iron oxide (SPIO)-labeled stem cells offers a non-invasive evaluation of stem cell engraftment in host organs. Excessive cellular iron load from SPIO labeling, however, impairs stem cell differentiation. The purpose of this study was to magnetically label human embryonic stem cells (hESCs) via a reduced exposure protocol that maintains a significant MR signal and no significant impairment to cellular pluripotency or differentiation potential. hESCs were labeled by simple incubation with Food and Drug Administration-approved ferumoxides, using concentrations of 50–200 μg Fe/ml and incubation times of 3–24 h. The most reduced exposure labeling protocol that still provided a significant MR signal comparable to accepted labeling protocols was selected for subsequent studies. Labeled hESCs were compared to unlabeled controls for differences in pluripotency as studied by fluorescence staining for SSEA-1, SSEA-4, TRA-60, and TRA-81 and in differentiation capacity as studied by quantitative real-time PCR for hOCT4, hACTC1, hSOX1, and hAFP after differentiation into embryoid bodies (EBs). Subsequent MR and microscopy imaging were performed to evaluate for cellular iron distribution and long-term persistence of the label. An incubation concentration of 50 μg Fe/ml and incubation time of 3 h demonstrated a significantly reduced exposure protocol that yielded an intracellular iron uptake of 4.50 ± 0.27 pg, an iron content comparable to currently accepted SPIO labeling protocols. Labeled and unlabeled hESCs showed no difference in pluripotency or differentiation capacity. Ferumoxide-labeled hESCs demonstrated persistent MR contrast effects as embryoid bodies for 21 days. Electron microscopy confirmed persistent lysosomal storage of iron oxide particles in EBs up to 9 days, while additional microscopy confirmed the iron distribution within single and multiple EBs. Labeling hESCs with ferumoxides by this tailored protocol reduces exposure of cells to the labeling agent while allowing for long-term visualization with MR imaging and the retention of cellular pluripotency and differentiation potential.

Mammalian nuclear receptors broadly influence metabolic fitness and serve as popular targets for developing drugs to treat cardiovascular disease, obesity, and diabetes. However, the molecular mechanisms and regulatory pathways that govern lipid metabolism remain poorly understood. We previously found that the Caenorhabditis elegans nuclear hormone receptor NHR-49 regulates multiple genes in the fatty acid beta-oxidation and desaturation pathways. Here, we identify additional NHR-49 targets that include sphingolipid processing and lipid remodeling genes. We show that NHR-49 regulates distinct subsets of its target genes by partnering with at least two other distinct nuclear receptors. Gene expression profiles suggest that NHR-49 partners with NHR-66 to regulate sphingolipid and lipid remodeling genes and with NHR-80 to regulate genes involved in fatty acid desaturation. In addition, although we did not detect a direct physical interaction between NHR-49 and NHR-13, we demonstrate that NHR-13 also regulates genes involved in the desaturase pathway. Consistent with this, gene knockouts of these receptors display a host of phenotypes that reflect their gene expression profile. Our data suggest that NHR-80 and NHR-13's modulation of NHR-49 regulated fatty acid desaturase genes contribute to the shortened lifespan phenotype of nhr-49 deletion mutant animals. In addition, we observed that nhr-49 animals had significantly altered mitochondrial morphology and function, and that distinct aspects of this phenotype can be ascribed to defects in NHR-66- and NHR-80-mediated activities. Identification of NHR-49's binding partners facilitates a fine-scale dissection of its myriad regulatory roles in C. elegans. Our findings also provide further insights into the functions of the mammalian lipid-sensing nuclear receptors HNF4α and PPARα.

Transforming growth factor β (TGF-β) signaling acts through Smad proteins to play fundamental roles in cell proliferation, differentiation, apoptosis, and metabolism. The Receptor associated Smads (R-Smads) interact with DNA and other nuclear proteins to regulate target gene transcription. Here, we demonstrate that the Caenorhabditis elegans R-Smad DAF-8 partners with the nuclear hormone receptor NHR-69, a C. elegans ortholog of mammalian hepatocyte nuclear factor 4α HNF4α), to repress the exp-2 potassium channel gene and increase insulin secretion. We find that NHR-69 associates with DAF-8 both in vivo and in vitro. Functionally, daf-8 nhr-69 double mutants show defects in neuropeptide secretion and phenotypes consistent with reduced insulin signaling such as increased expression of the sod-3 and gst-10 genes and a longer life span. Expression of the exp-2 gene, encoding a voltage-gated potassium channel, is synergistically increased in daf-8 nhr-69 mutants compared to single mutants and wild-type worms. In turn, exp-2 acts selectively in the ASI neurons to repress the secretion of the insulin-like peptide DAF-28. Importantly, exp-2 mutation shortens the long life span of daf-8 nhr-69 double mutants, demonstrating that exp-2 is required downstream of DAF-8 and NHR-69. Finally, animals over-expressing NHR-69 specifically in DAF-28-secreting ASI neurons exhibit a lethargic, hypoglycemic phenotype that is rescued by exogenous glucose. We propose a model whereby DAF-8/R-Smad and NHR-69 negatively regulate the transcription of exp-2 to promote neuronal DAF-28 secretion, thus demonstrating a physiological crosstalk between TGF-β and HNF4α-like signaling in C. elegans. NHR-69 and DAF-8 dependent regulation of exp-2 and DAF-28 also provides a novel molecular mechanism that contributes to the previously recognized link between insulin and TGF-β signaling in C. elegans.

Gene regulatory networks (GRNs) provide insights into the mechanisms of differential gene expression at a systems level. GRNs that relate to metazoan development have been studied extensively. However, little is still known about the design principles, organization and functionality of GRNs that control physiological processes such as metabolism, homeostasis and responses to environmental cues. In this study, we report the first experimentally mapped metazoan GRN of Caenorhabditis elegans metabolic genes. This network is enriched for nuclear hormone receptors (NHRs). The NHR family has greatly expanded in nematodes: humans have 48 NHRs, but C. elegans has 284, most of which are uncharacterized. We find that the C. elegans metabolic GRN is highly modular and that two GRN modules predominantly consist of NHRs. Network modularity has been proposed to facilitate a rapid response to different cues. As NHRs are metabolic sensors that are poised to respond to ligands, this suggests that C. elegans GRNs evolved to enable rapid and adaptive responses to different cues by a concurrence of NHR family expansion and modular GRN wiring.

In eukaryotes, RNA polymerase II (Pol(II)) dependent gene expression requires accessory factors termed transcriptional coregulators. One coregulator that universally contributes to Pol(II)-dependent transcription is the Mediator, a multisubunit complex that is targeted by many transcriptional regulatory factors. For example, the Caenorhabditis elegans Mediator subunit MDT-15 confers the regulatory actions of the sterol response element binding protein SBP-1 and the nuclear hormone receptor NHR-49 on fatty acid metabolism. Here, we demonstrate that MDT-15 displays a broader spectrum of activities, and that it integrates metabolic responses to materials ingested by C. elegans. Depletion of MDT-15 protein or mutation of the mdt-15 gene abrogated induction of specific detoxification genes in response to certain xenobiotics or heavy metals, rendering these animals hypersensitive to toxin exposure. Intriguingly, MDT-15 appeared to selectively affect stress responses related to ingestion, as MDT-15 functional defects did not abrogate other stress responses, e.g., thermotolerance. Together with our previous finding that MDT-15:NHR-49 regulatory complexes coordinate a sector of the fasting response, we propose a model whereby MDT-15 integrates several transcriptional regulatory pathways to monitor both the availability and quality of ingested materials, including nutrients and xenobiotic compounds.

Magnetically induced current densities, nuclear magnetic shieldings, and electric polarizabilities of planar ring-shaped hydrocarbons have been studied at the density-functional theory level using the Becke−Perdew (BP86) functional. The current densities were calculated using the Gauge-Including Magnetically Induced Current (GIMIC) method employing gauge-including atomic orbitals. The GIMIC calculations yield rules to estimate the global and local ring−current strengths as well as the current pathways for the hydrocarbon nanorings. For the overall antiaromatic molecules, aromatic groups such as benzene, naphthalene, anthracene, and pyrene moieties localize the ring current making the global ring currents vanish. The ability of the edge groups to localize the currents is related to the aromatic character of the molecule as a whole. The local ring current prefers to follow the edges of the group. Phenalenyl corner moieties are found to introduce strong global ring currents, whereas with fused benzene and pyrene corner groups the global ring current vanishes. Fused benzene rings in the corner or along the edge of overall antiaromatic molecules sustain local ring currents of about the same size as for a free benzene molecule. For the overall aromatic molecules, the global ring current is split along the bonds of the edge moieties, but the detailed division fulfilling Kirchhoff’s current law is not easily predictable and must be calculated for each individual bond. At the phenalenyl corner moieties, the global ring current follows the innermost route isolating the rest of the group from the main delocalization pathway. A hydrocarbon nanoring sustaining strong ring currents should be large and formally aromatic with many and large aromatic moieties along the edges. A clear correlation between the strength of the global ring currents and the size of the electric polarizabilities is obtained. The calculated 1H NMR shieldings of a proton in immediate contact to the global ring current vary between 22 ppm and 67 ppm in the studied molecules. The trend correlates well with the global ring−current strengths, which are in the range of 0−88 nA/T. The 13C NMR shieldings are also sensitive to the strength of the global ring current, but they vary less systematically and are not as good an indicator of the current strength as the hydrogen shieldings. [ABSTRACT FROM AUTHOR]

We report density functional theory (DFT) studies on the endohedral scandium carbide fullerene Sc3C2@C80and its monoanion [Sc3C2@C80]−. The system consisting of a Sc3C2moiety inside the IhC80fullerene has been studied by using first principles molecular dynamics simulations at the DFT level. On the picosecond time scale, the triangle defined by the scandium atoms is seen to jump between orientations along the equatorial six-membered ring belt of the cage. The confined carbide unit, in turn, is engaged in a flipping motion through the Sc3plane. In contrast to the equilibrium geometry optimisations using large basis sets that predict a trigonal bipyramidal structure, a planar Sc3C2-moiety is preferred during the finite-temperature simulation. In the molecular dynamics picture, Sc3C2@C80is best described as an equilibrium between the two static minimum structures. Calculations of the vibrational frequencies show that the earlier predicted C2and C2vsymmetric isomers are in fact saddle points, with one imaginary normal mode frequency that is related to the flipping motion of the confined carbon dimer. Reoptimisation revealed two new minimum energy structures where the C2unit is tilted with respect to its orientation in the earlier suggested higher-symmetry structures. The nature of the bonding in the static structures of the two isomers of Sc3C2@C80has been investigated using the electron localisation function and natural population analysis. Some increased electron pair localisation is detected on the six-membered rings closest to the Sc atoms. 13C nuclear magnetic resonance (NMR) chemical shifts have been calculated for the closed-shell monoanion of Sc3C2@C80. The 13C shifts were also calculated for Sc2C2@C84, for further comparison to experimentally measured spectra. The confined carbon atoms are strongly deshielded in these metallofullerenes, implying an incorrect earlier interpretation of the experimental 13C NMR spectrum of Sc2C2@C84. The neutral Sc3C2@C80system with one unpaired electron is further characterised by calculating the hyperfine coupling constants, the gtensor, as well as paramagnetic NMR (pNMR) 13C shifts for both static isomers. The chemical shifts of the confined carbon atoms and the hyperfine coupling constants of all the confined atoms are strongly dependent on the conformation of the Sc3C2moiety. Consequently, dynamical effects are expected to be important in the modelling of the magnetic properties of endohedral scandium carbide fullerenes. The two low-lying isomers have rather different pNMR 13C shifts, implying the potential of this method in structural assignment. [ABSTRACT FROM AUTHOR]