Ferritin is regulated by a neuro-intestinal axis in the nematode Caenorhabditis elegans

Causal relationship between iron status and preeclampsia-eclampsia: a Mendelian randomization analysis

BACKGROUND

Preeclampsia/eclampsia is a severe pregnancy-related disorder associated with hypertension and organ damage. While observational studies have suggested a link between maternal iron status and preeclampsia/eclampsia, the causal relationship remains unclear. The aim of this study was to investigate the genetic causality between iron status and preeclampsia/eclampsia using large-scale genome-wide association study (GWAS) summary data and Mendelian randomization (MR) analysis.

METHODS

Summary data for the GWAS on preeclampsia/eclampsia and genetic markers related to iron status were obtained from the FinnGen Consortium and the IEU genetic databases. The "TwoSampleMR" software package in R was employed to test the genetic causality between these markers and preeclampsia/eclampsia. The inverse variance weighted (IVW) method was primarily used for MR analysis. Heterogeneity, horizontal pleiotropy, and potential outliers were evaluated for the MR analysis results.

RESULTS

The random-effects IVW results showed that ferritin (OR = 1.11, 95% CI: .89-1.38, p = .341), serum iron (OR = .90, 95% CI: .75-1.09, p = .275), TIBC (OR = .98, 95% CI: .89-1.07, p = .613), and TSAT (OR = .94, 95% CI: .83-1.07, p = .354) have no genetic causal relationship with preeclampsia/eclampsia. There was no evidence of heterogeneity, horizontal pleiotropy, or possible outliers in our MR analysis (p > .05).

CONCLUSIONS

Our study did not detect a genetic causal relationship between iron status and preeclampsia/eclampsia. Nonetheless, this does not rule out a relationship between the two at other mechanistic levels.

Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans

Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, VHL-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism and stress response. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.

Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans

Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, SWAN-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism, hypoxia and other stress responses, reproduction and development. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.

Systematic characterization of Lysergic Acid Diethylamide metabolites in Caenorhabditis elegans by ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry

Psychedelic compounds have gained renewed interest for their potential therapeutic applications, but their metabolism and effects on complex biological systems remain poorly understood. Here, we present a systematic characterization of Lysergic Acid Diethylamide (LSD) metabolites in the model organism Caenorhabditis elegans using state-of-the-art analytical techniques. By employing ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry, we putatively identified a range of LSD metabolites, shedding light on their metabolic pathways and offering insights into their pharmacokinetics. Our study demonstrates the suitability of Caenorhabditis elegans as a valuable model system for investigating the metabolism of psychedelic compounds and provides a foundation for further research on the therapeutic potential of LSD.

Role of ferroptosis in effects of anesthetics on multiple organ diseases: A literature review

Anesthesiologists are often faced with patients combined with a series of organ injuries, such as acute lung injury, myocardial ischemia-reperfusion injury, and neurodegenerative diseases. With the in-depth study of these diseases, we are more aware of the choice and rational use of anesthetics for the prognosis of these patients. Ferroptosis is a new type of programmed cell death. This unique pattern of cell death, driven by an imbalance between oxides and antioxidants, is regulated by multiple cellular metabolic events, including redox homeostasis, iron handling, mitochondrial activity, and lipids peroxidation. Numerous studies confirmed that anesthetics modulate ferroptosis by interfering its machineries such as cystine-import-glutathione-glutathione peroxidase 4 axis, Heme oxygenase 1, nuclear factor erythroid 2-related factor 2, and iron homeostasis system. In this literature review, we systemically illustrated possible involvement of ferroptosis in effects of anesthetics and adjuvant drugs on multiple organ diseases, hoping our work may serve as a basis for further studies on regulating ferroptosis through anesthetics related pharmacological modulation and promoting the rational use of anesthetics.

Distinct designer diamines promote mitophagy, and thereby enhance healthspan in C. elegans and protect human cells against oxidative damage

Impaired mitophagy is a primary pathogenic event underlying diverse aging-associated diseases such as Alzheimer and Parkinson diseases and sarcopenia. Therefore, augmentation of mitophagy, the process by which defective mitochondria are removed, then replaced by new ones, is an emerging strategy for preventing the evolvement of multiple morbidities in the elderly population. Based on the scaffold of spermidine (Spd), a known mitophagy-promoting agent, we designed and tested a family of structurally related compounds. A prototypic member, 1,8-diaminooctane (VL-004), exceeds Spd in its ability to induce mitophagy and protect against oxidative stress. VL-004 activity is mediated by canonical aging genes and promotes lifespan and healthspan in C. elegans. Moreover, it enhances mitophagy and protects against oxidative injury in rodent and human cells. Initial structural characterization suggests simple rules for the design of compounds with improved bioactivity, opening the way for a new generation of agents with a potential to promote healthy aging.

Structural and functional relationship of mammalian and nematode ferritins

Ferritin is a unique buffering protein in iron metabolism. By storing or releasing iron in a tightly controlled manner, it prevents the negative effects of free ferrous ions on biomolecules in all domains of life - from bacteria to mammals. This review focuses on the structural features and activity of the ferritin protein family with an emphasis on nematode ferritins and the similarities in their biological roles with mammalian ferritins. The conservative characteristic of the ferritin family across the species originates from the ferroxidase activity against redox-active iron. The antioxidative function of these proteins translates into their involvement in a wide range of important biological processes, e.g., aging, fat metabolism, immunity, anticancer activity, and antipathogenic activity. Moreover, disturbances in ferritin expression lead to severe iron-associated diseases. Research on the Caenorhabditis elegans model organism may allow us to better understand the wide spectrum of mechanisms involving ferritin activity.

Sublethal effects of DBE-DBCH diastereomers on physiology, behavior, and gene expression of Daphnia magna

1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH) is a brominated flame retardant used in commercial and industrial applications. The use of DBE-DBCH containing products has resulted in an increased release into the environment. However, limited information is available on the long-term effects of DBE-DBCH and its effects in aquatic invertebrates. Thus, the present study was aimed at determining how DBE-DBCH diastereomers (αβ and γδ) affects aquatic invertebrates using Daphnia magna as a model organism. Survival, reproduction, feeding, swimming behavior and toxicogenomic responses to environmental relevant concentrations of DBE-DBCH were analyzed. Chronic exposure to DBE-DBCH resulted in decreased lifespan, and reduced fecundity. Expression of genes involved in reproductive processes, vtg1 and jhe, were also inhibited. DBE-DBCH also induced hypoxia by inhibiting the transcription of genes involved in heme biosynthesis and oxygen transport. Furthermore, DBE-DBCH also inhibited feeding resulting in emptiness of the alimentary canal. Increased expression of the stress response biomarkers was observed following DBE-DBCH exposure. In addition, DBE-DBCH diastereomers also altered the swimming behavior of Daphnia magna. The present study demonstrates that DBE-DBCH cause multiple deleterious effects on Daphnia magna, including effects on reproduction and hormonal systems. These endocrine disrupting effects are in agreement with effects observed on vertebrates. Furthermore, as is the case in vertebrates, DBE-DBCH γδ exerted stronger effects than DBE-DBCH αβ on Daphnia magna. This indicate that DBE-DBCH γδ has properties making it more toxic to all so far studied animals than DBE-DBCH αβ.

Allele-specific mitochondrial stress induced by Multiple Mitochondrial Dysfunctions Syndrome 1 pathogenic mutations modeled in Caenorhabditis elegans

Multiple Mitochondrial Dysfunctions Syndrome 1 (MMDS1) is a rare, autosomal recessive disorder caused by mutations in the NFU1 gene. NFU1 is responsible for delivery of iron-sulfur clusters (ISCs) to recipient proteins which require these metallic cofactors for their function. Pathogenic variants of NFU1 lead to dysfunction of its target proteins within mitochondria. To date, 20 NFU1 variants have been reported and the unique contributions of each variant to MMDS1 pathogenesis is unknown. Given that over half of MMDS1 individuals are compound heterozygous for different NFU1 variants, it is valuable to investigate individual variants in an isogenic background. In order to understand the shared and unique phenotypes of NFU1 variants, we used CRISPR/Cas9 gene editing to recreate exact patient variants of NFU1 in the orthologous gene, nfu-1 (formerly lpd-8), in C. elegans. Five mutant C. elegans alleles focused on the presumptive iron-sulfur cluster interaction domain were generated and analyzed for mitochondrial phenotypes including respiratory dysfunction and oxidative stress. Phenotypes were variable between the mutant nfu-1 alleles and generally presented as an allelic series indicating that not all variants have lost complete function. Furthermore, reactive iron within mitochondria was evident in some, but not all, nfu-1 mutants indicating that iron dyshomeostasis may contribute to disease pathogenesis in some MMDS1 individuals.

Functional mitochondria are essential to life in eukaryotes, but they can be perterbured by inherent dysfunction of important proteins or stressors. Mitochondrial dysfunction is the root cause of dozens of diseases many of which involve complex phenotypes. One such disease is Multiple Mitochondrial Dysfunctions Syndrome 1, a pediatric-fatal disease that is poorly understood in part due to the lack of clarity about how mutations in the causative gene, NFU1, affect protein function and phenotype development and severity. Here we employ the power of CRISPR/Cas9 gene editing in the small nematode Caenorhabditis elegans to recreate five patient-specific mutations known to cause Multiple Mitochondrial Dysfunctions Syndrome 1. We are able to analyze each of these mutations individually, evaluate how mitochondrial dysfunction differs between them, and whether or not the phenotypes can be improved. We find that there are meaningful differences between each mutation which not only effects the types of stress that develop, but also the ability to rescue deleterious phenotypes. This work thus provides insight into disease pathogenesis and establishes a foundation for potential future therapeutic intervention.

Hypoxic response regulators RHY-1 and EGL-9/PHD promote longevity through a VHL-1-independent transcriptional response

HIF-1-mediated adaptation to changes in oxygen availability is a critical aspect of healthy physiology. HIF is regulated by a conserved mechanism whereby EGLN/PHD family members hydroxylate HIF in an oxygen-dependent manner, targeting it for ubiquitination by Von-Hippel-Lindau (VHL) family members, leading to its proteasomal degradation. The activity of the only C. elegans PHD family member, EGL-9, is also regulated by a hydrogen sulfide sensing cysteine-synthetase-like protein, CYSL-1, which is, in turn, regulated by RHY-1/acyltransferase. Over the last decade, multiple seminal studies have established a role for the hypoxic response in regulating longevity, with mutations in vhl-1 substantially extending C. elegans lifespan through a HIF-1-dependent mechanism. However, studies on other components of the hypoxic signaling pathway that similarly stabilize HIF-1 have shown more mixed results, suggesting that mutations in egl-9 and rhy-1 frequently fail to extend lifespan. Here, we show that egl-9 and rhy-1 mutants suppress the long-lived phenotype of vhl-1 mutants. We also show that RNAi of rhy-1 extends lifespan of wild-type worms while decreasing lifespan of vhl-1 mutant worms. We further identify VHL-1-independent gene expression changes mediated by EGL-9 and RHY-1 and find that a subset of these genes contributes to longevity regulation. The resulting data suggest that changes in HIF-1 activity derived by interactions with EGL-9 likely contribute greatly to its role in regulation of longevity.