Search Results (168)

Neuroinflammation is the major contributor to the pathology of neonatal hypoxic–ischemic (HI) brain injury. Our previous studies have demonstrated that microRNA210 (miR210) inhibition with antisense locked nucleic acid (LNA) inhibitor mitigates neuroinflammation and provides neuroprotection after neonatal HI insult. However, the underlying mechanisms remain elusive. In the present study, using miR210 knockout (KO) mice and microglial cultures, we tested the hypothesis that miR210 promotes microglial activation and neuroinflammation through suppressing mitochondrial function in microglia after HI. Neonatal HI brain injury was conducted on postnatal day 9 (P9) wild-type (WT) and miR210 knockout (KO) mouse pups. We found that miR210 KO significantly reduced brain infarct size at 48 h and improved long-term locomotor functions assessed by an open field test three weeks after HI. Moreover, miR210 KO mice exhibited reduced IL1β levels, microglia activation and immune cell infiltration after HI. In addition, in vitro studies of microglia exposed to oxygen–glucose deprivation (OGD) revealed that miR210 inhibition with LNA reduced OGD-induced expression of Il1b and rescued OGD-mediated downregulation of mitochondrial iron–sulfur cluster assembly enzyme (ISCU) and mitochondrial oxidative phosphorylation activity. To validate the link between miR210 and microglia activation, isolated primary murine microglia were transfected with miR210 mimic or negative control. The results showed that miR210 mimic downregulated the expression of mitochondrial ISCU protein abundance and induced the expression of proinflammatory cytokines similar to the effect observed with ISCU silencing RNA. In summary, our results suggest that miR210 is a key regulator of microglial proinflammatory activation through reprogramming mitochondrial function in neonatal HI brain injury. Full article

Snails at hydrothermal vents rely on symbiotic bacteria for nutrition; however, the specifics of these associations in adapting to such extreme environments remain underexplored. This study investigated the community structure and metabolic potential of bacteria associated with two Indian Ocean vent snails, Chrysomallon squamiferum and Gigantopelta aegis. Using microscopic, phylogenetic, and metagenomic analyses, this study examines bacterial communities inhabiting the foot and gland tissues of these snails. G. aegis exhibited exceptionally low bacterial diversity (Shannon index 0.14–0.18), primarily Gammaproteobacteria (99.9%), including chemosynthetic sulfur-oxidizing Chromatiales using Calvin–Benson–Bassham cycle and methane-oxidizing Methylococcales in the glands. C. squamiferum hosted significantly more diverse symbionts (Shannon indices 1.32–4.60). Its black variety scales were dominated by Campylobacterota (67.01–80.98%), such as Sulfurovum, which perform sulfur/hydrogen oxidation via the reductive tricarboxylic acid cycle, with both Campylobacterota and Gammaproteobacteria prevalent in the glands. The white-scaled variety of C. squamiferum had less Campylobacterota but a higher diversity of heterotrophic bacteria, including Delta-/Alpha-Proteobacteria, Bacteroidetes, and Firmicutes (classified as Desulfobacterota, Pseudomomonadota, Bacteroidota, and Bacillota in GTDB taxonomy). In C. squamiferum, Gammaproteobacteria, including Chromatiales, Thiotrichales, and a novel order “Endothiobacterales,” were chemosynthetic, capable of oxidizing sulfur, hydrogen, or iron, and utilizing the Calvin–Benson–Bassham cycle for carbon fixation. Heterotrophic Delta- and Alpha-Proteobacteria, Bacteroidetes, and Firmicutes potentially utilize organic matter from protein, starch, collagen, amino acids, thereby contributing to the holobiont community and host nutrition accessibility. The results indicate that host species and intra-species variation, rather than the immediate habitat, might shape the symbiotic microbial communities, crucial for the snails’ adaptation to vent ecosystems. Full article

Bambara groundnut (Vigna subterranean) is an important legume grain in sub-Saharan Africa, including South Africa. Nevertheless, the peculiarity of being hard to cook and mill and the availability of antinutritional factors often limit Bambara groundnut (BGN) use in food applications. This study investigated the impact of dehulling and malting on the nutritional composition, antinutritional factors, and protein digestibility of flours obtained from three BGN varieties (red, cream, and brown). Dehulling and malting significantly enhanced the moisture and protein content of BGN flours (dry basis), with values varying from 6.01% (control brown variety) to 8.71% (malted cream and brown varieties), and from 18.63% (control red variety) to 21.87% (dehulled brown), respectively. Dehulling increased the fat content from 5.82% (control red variety) to 7.84% (dehulled cream), whereas malting decreased the fat content. Nevertheless, malting significantly increased (p < 0.05) the fiber content from 4.78% (control cream) to 8.28% (malted brown variety), while dehulling decreased the fiber content. Both processing methods decreased the ash and carbohydrate contents of the BGN flours. Dehulling and malting significantly enhanced the amino acids of BGN flours, except for tryptophan and asparagine. Dehulling and malting notably increased the phosphorus, magnesium, potassium, and sulfur contents of the BGN flours, while calcium and zinc were reduced. Malting significantly enhanced the iron content of BGN flour, whereas dehulling reduced it. Both processing methods significantly enhanced palmitic, arachidic, and y-Linolenic acids. Nonetheless, processing methods significantly reduced phytic acid and oxalate, and dehulling achieved the most significant reductions. Dehulling and malting significantly enhanced the protein digestibility of the BGN flours from 69.38 (control red variety) to 83.29 g/100 g (dehulled cream variety). Overall, dehulling and malting enhanced the nutritional quality and decreased the antinutritional factors of BGN flours. Full article

Ethylmalonic encephalopathy (EE) is a serious metabolic disorder that usually appears in early childhood development and the effects are seen primarily in the brain, gastrointestinal tract, and peripheral vessels. EE is caused by pathogenic variants in the gene that encodes the ETHE1 protein, and its main features are high levels of acidic compounds in body fluids and decreased activity of the mitochondrial complex IV, which limits energy production in tissues that require a large supply of energy. ETHE1 is a mitochondrial sulfur dioxygenase that plays the role of hydrogen sulfide (H₂S) detoxification, and, when altered, it leads to the accumulation of this gaseous molecule due to its deficient elimination. In this article, we characterised the pathophysiology of ETHE1 deficiency in cellular models, fibroblasts, and induced neurons, derived from a patient with a homozygous pathogenic variant in ETHE1. Furthermore, we evaluated the effect of the activation of the mitochondrial unfolded protein response (mtUPR) on the mutant phenotype. Our results suggest that mutant fibroblasts have alterations in ETHE1 protein expression levels, associated with elevated levels of H₂S and protein persulfidation, mitochondrial dysfunction, iron/lipofuscin accumulation, and oxidative stress. We also identified a cocktail of compounds consisting of pterostilbene, nicotinamide, riboflavin, thiamine, biotin, lipoic acid, and L-carnitine that improved the cellular and metabolic alterations. The positive effect of the cocktail was dependent on sirtuin 3 activation (SIRT3) and was also confirmed in induced neurons obtained by direct reprogramming. In conclusion, personalised precision medicine in EE using patient-derived cellular models can be an interesting approach for the screening and evaluation of potential therapies. In addition, the activation of the SIRT3 axe of mtUPR is a promising therapeutic strategy for rescuing ETHE1 pathogenic variants. Full article

Frataxin is a component of the iron–sulfur (Fe-S) cluster assembly complex in mitochondria, and deficiency is associated with Friedreich ataxia (FA). The yeast homolog Yfh1 resembles and cross-complements with its human equivalent, and frataxin bypass scenarios are of particular interest because they may point to strategies for treating FA. Here, we describe frataxin/Yfh1 bypass by overexpression of Rsm22, an assembly factor for the mitochondrial ribosome. Rsm22 overexpression in Yfh1-depleted yeast cells restored critical processes in mitochondria, including Fe-S cluster assembly, lipoic acid synthesis, iron homeostasis, and heme synthesis, to a significant extent. Formation of cytoplasmic Fe-S proteins was also restored, suggesting recovery of the mitochondrial ability to generate the (Fe-S)_int intermediate that is exported from mitochondria and is utilized for cytoplasmic Fe-S cluster assembly. Importantly, an essential component of the mitochondrial iron–sulfur cluster machinery, namely ferredoxin, was virtually absent in mitochondria lacking Yfh1, but it was recovered with Rsm22 overexpression. Interestingly, ferredoxin overexpression could offset some of the effects of Yfh1 depletion. Ferredoxin has recently been shown to bind to the cysteine desulfurase protein Nfs1 at the same site as Yfh1, in a conserved arginine patch on Nfs1, such that ferredoxin binding at this site may confer frataxin-bypass activity. Full article

The BCS1L gene encodes a mitochondrial chaperone which inserts the Fe₂S₂ iron–sulfur Rieske protein into the nascent electron transfer complex III. Variants in the BCS1L gene are associated with a spectrum of mitochondrial disorders, ranging from mild to severe phenotypes. Björnstad syndrome, a milder condition, is characterized by sensorineural hearing loss (SNHL) and pili torti. More severe disorders include Complex III Deficiency, which leads to neuromuscular and metabolic dysfunctions with multi-systemic issues and Growth Retardation, Aminoaciduria, Cholestasis, Iron Overload, and Lactic Acidosis syndrome (GRACILE). The severity of these conditions varies depending on the specific BCS1L mutation and its impact on mitochondrial function. This study describes a 27-month-old child with SNHL, proximal renal tubular acidosis, woolly hypopigmented hair, developmental delay, and metabolic alterations. Genetic analysis revealed a homozygous BCS1L variant (c.38A>G, p.Asn13Ser), previously reported in a patient with a more severe phenotype that, however, was not functionally characterized. In this work, functional studies in a yeast model and patient-derived fibroblasts demonstrated that the variant impairs mitochondrial respiration, complex III activity (CIII), and also alters mitochondrial morphology in affected fibroblasts. Interestingly, we unveil a new possible mechanism of pathogenicity for BCS1L mutant protein. Since the interaction between BCS1L and CIII is increased, this suggests the formation of a BCS1L-containing nonfunctional preCIII unable to load RISP protein and complete CIII assembly. These findings support the pathogenicity of the BCS1L c.38A>G variant, suggesting altered interaction between the mutant BCS1L and CIII. Full article

Accurate DNA replication is essential for the maintenance of genome stability and the generation of healthy offspring. When DNA replication is challenged, signals accumulate at blocked replication forks that elicit a multifaceted cellular response, orchestrating DNA replication, DNA repair and cell cycle progression. This replication stress response promotes the recovery of DNA replication, maintaining chromosome integrity and preventing mutations. Defects in this response are linked to heightened genetic instability, which contributes to tumorigenesis and genetic disorders. Iron–sulfur (Fe-S) clusters are emerging as important cofactors in supporting the response to replication stress. These clusters are assembled and delivered to target proteins that function in the cytosol and nucleus via the conserved cytosolic Fe-S cluster assembly (CIA) machinery and the CIA targeting complex. This review summarizes recent advances in understanding the structure and function of the CIA machinery in yeast and mammals, emphasizing the critical role of Fe-S clusters in the replication stress response. Full article

Background/Objectives: Antibiotic-resistant Staphylococcus aureus represents a growing threat in the modern world, and new antibiotic targets are needed for its successful treatment. One such potential target is the pyridoxal-5′-phosphate (PLP)-dependent cysteine desulfurase (SaSufS) of the SUF-like iron–sulfur (Fe-S) cluster biogenesis pathway upon which S. aureus relies exclusively for Fe-S synthesis. The current methods for measuring the activity of this protein have allowed for its recent characterization, but they are hampered by their use of chemical reagents which require long incubation times and may cause undesired side reactions. This problem highlights a need for the development of a rapid quantitative assay for the characterization of SaSufS in the presence of potential inhibitors. Methods: A spectrophotometric assay based on the well-documented absorbance of PLP intermediates at 340 nm was both compared to an established alanine detection assay and used to effectively measure the activity of SaSufS incubated in the absence and presence of the PLP-binding inhibitors, D-cycloserine (DCS) and L-cycloserine (LCS) as proof of concept. Methicillin-resistant S. aureus strain LAC was also grown in the presence of these inhibitors. Results: The Michaelis–Menten parameters k_cat and K_m of SaSufS were determined using the alanine detection assay and compared to corresponding intermediate-based values obtained spectrophotometrically in the absence and presence of the reducing agent tris(2-carboxyethyl)phosphine (TCEP). These data revealed the formation of both an intermediate that achieves steady-state during continued enzyme turnover and an intermediate that likely accumulates upon the stoppage of the catalytic cycle during the second turnover. The spectrophotometric method was then utilized to determine the half maximal inhibitory concentration (IC₅₀) values for DCS and LCS binding to SaSufS, which are 2170 $\pm$ 920 and 62 $\pm$ 23 μM, respectively. Both inhibitors of SaSufS were also found to inhibit the growth of S. aureus. Conclusions: Together, this work offers a spectrophotometric method for the analysis of new inhibitors of SufS and lays the groundwork for the future development of novel antibiotics targeting cysteine desulfurases. Full article

Glutathione S-transferases (GSTs) are evolutionarily conserved enzymes crucial for cell detoxication. They are viewed as having evolved in cyanobacteria, the ancient photosynthetic prokaryotes that colonize our planet and play a crucial role for its biosphere. Xi-class GSTs, characterized by their specific glutathionyl–hydroquinone reductase activity, have been observed in prokaryotes, fungi and plants, but have not yet been studied in cyanobacteria. In this study, we have analyzed the presumptive Xi-class GST, designated as Slr0605, of the unicellular model cyanobacterium Synechocystis PCC 6803. We report that Slr0605 is a homodimeric protein that has genuine glutathionyl–hydroquinone reductase activity. Though Slr0605 is not essential for cell growth under standard photoautotrophic conditions, it plays a prominent role in the protection against not only benzoquinone, but also cobalt-excess stress. Indeed, Slr0605 acts in defense against the cobalt-elicited disturbances of iron homeostasis, iron–sulfur cluster repair, catalase activity and the level of reactive oxygen species, which are all crucial for cell life. Full article

Selenium (Se) is an essential element for humans. However, much of the world’s human population is deficient in this element, which has become a public health problem. This study aimed to evaluate whether applying severe water stress to wheat plants (Triticum aestivum L.) could allow Se to reduce the production losses and increase the grain quality, thereby contributing to the reduction in hidden hunger. The experiment was conducted in a randomized block design with four replications in a 5 × 2 factorial scheme, with five doses of Se (0.00, 0.25, 0.50, 1.00, and 2.00 mg dm⁻³) and two irrigation conditions (with and without water deficit). When sodium selenate (Na₂SeO₄) was applied to the soil, the grains were rich in Se. Under low doses, there was an enrichment of the grains in sulfur, iron, copper, and zinc as well as total free amino acids and total soluble proteins, and lower losses in productivity under severe water stress. Higher doses decreased the concentration of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), increased the catalase activity, and increased the water use efficiency (WUE). Therefore, applying Se at a dose of 0.25 mg dm⁻³ is effective for the biofortification of wheat grains. It enhances grain nutritional quality, increases Se bioaccessibility, and reduces production losses under water stress conditions. Full article

Iron–sulfur (Fe-S) clusters are essential cofactors found in many proteins in the mitochondria, cytosol, and nucleus of the cell. These versatile cofactors may undergo reversible oxidation–reduction reactions to enable electron transfers; they may be structural and confer stability to a folded protein; they may be regulatory and transduce an iron signal that alters the function or stability of a recipient protein. Of the nearly 70 proteins described in mammalian cells that bind Fe-S clusters, about half localize exclusively or partially to the nucleus, where they are required for DNA replication and repair, telomere maintenance, transcription, mitosis, and cell cycle control. Most nuclear Fe-S cluster proteins interact with DNA, including DNA polymerases, primase, helicases, and glycosylases. However, the specific roles of the clusters in the enzymatic activities of these proteins and their interplay with DNA remain a matter of debate. Defects in the metallation of nuclear Fe-S proteins cause genome instability and alter the regulation of cell division and proliferation, which are hallmarks of various genetic diseases and cancers. Here, we provide an inventory of the nuclear Fe-S cluster-binding proteins and discuss cluster types, binding sites, the process of cluster acquisition, and the potential roles of the cluster in the function of the proteins. However, many questions remain unresolved. We highlight critical gaps in our understanding of cluster delivery to nuclear client proteins, the potential for cluster repair, and the mechanistic roles that clusters play in these enzymes. Taken together, this review brings the focus to the nucleus of the human cell as a hotspot for Fe-S cluster proteins and aims to inspire new research on the roles of iron in DNA metabolism and the maintenance of genome integrity. Full article

Background: ISCA1 (Iron–Sulfur Cluster Assembly 1) is involved in the assembly of iron–sulfur (Fe–S) clusters, which are vital for electron transport and enzyme activity. Some studies suggest the potential involvement of ISCA1 in tumor progression through interactions with ferroptosis-related genes (FRGs) and the tumor immune microenvironment (TME). However, there has been no systematic analysis of its role in FRGs and the TME or its predictive value for prognosis and immunotherapy response across different cancer types. Methods: In this study, we analyzed the expression and prognosis of ISCA1 RNA, CNV, methylation, and protein in multiple tumor tissues via data from the TCGA and CPTAC databases and clinical information. We conducted a comprehensive analysis of the correlations between ISCA1 and FRGs, immune-related genes (including immune regulatory genes and immune checkpoint genes), immune cell infiltration, immune infiltration scores, tumor stemness, and genomic heterogeneity. Results: We performed drug prediction and validation through molecular docking and molecular dynamics analysis to identify candidate drugs that could promote or inhibit ISCA1 RNA expression. Our findings revealed that ISCA1 could serve as a biomarker in thyroid carcinoma, play a role with different FRGs in various cell types, and mediate different ligand–receptor pathways for cell–cell communication. Conclusions: Overall, our study highlights the potential of ISCA1 as a novel biomarker for predicting prognosis and immunotherapeutic efficacy in thyroid carcinoma and suggests its potential for developing novel antitumor drugs or improving immunotherapy. Full article

The cultivation of soybean is being expanded in traditional areas cultivated with rice, called the lowlands. However, soil characteristics are different from those in the highlands, which influences the exportation of nutrients to the grains. Therefore, this study aimed to determine the physical-chemical and technological characteristics of soybean grains harvested in lowlands in Brazil. Two-year crops (2021/22 and 2022/23) were used with two types of soil preparation (scarified and non-scarified) and six cover crop treatments (oats, clover, ryegrass, fallow, ryegrass + oats, and ryegrass + clover). The influence of these treatments was evaluated in terms of the grain yield, oil and protein contents, oil composition, quality indices (acidity, peroxide, iodine, and saponification), and contents of ash, carbohydrates, and micro- and macronutrients. Grain yield achieved an average of 3829.8 kg ha⁻¹. Soil scarification positively influenced grain yield and contributed to higher protein and oil contents, with maximum values of 32.7 wt% and 27.6 wt%, respectively. The main fatty acids in oil were oleic acid (22.13 ± 1.48–26.32 ± 0.98%) and linoleic acid (36.32 ± 1.57–52.18 ± 1.58%). The macronutrients phosphorus (5.12 ± 0.39–5.79 ± 0.37 kg ton⁻¹), calcium (2.79 ± 0.19–3.05 ± 0.18 kg ton⁻¹), magnesium (2.37 ± 0.14–2.57 ± 0.13 kg ton⁻¹), and sulfur (2.85 ± 0.18–3.19 ± 0.20 kg ton⁻¹), and the micronutrients copper (9.73 ± 1.42–11.68 ± 1.07 g ton⁻¹), iron (111.42 ± 6.86–122.02 ± 5.00 g ton⁻¹), and manganese (43.58 ± 3.34–47.08 ± 2.74 g ton⁻¹) were in agreement with the values reached in the highlands. For potassium (18.87 ± 0.38–29.29 ± 1.44 kg ton⁻¹) and zinc (30.02 ± 2.45–38.00 ± 1.03 g ton⁻¹), soil scarification allows higher levels of absorption. The use of ryegrass as a cover crop allows higher levels of nitrogen absorption, reaching up to 44.93 ± 2.74 kg ton⁻¹. Regarding the acidity (0.19–0.52%), peroxide (9.64–16.39 mEq O₂ kg⁻¹), iodine (85.34–91.91 mg KI g⁻¹), and saponification (182.33–203.74 mg KOH g⁻¹) indices of the oil, all values were obtained in accordance with the scientific literature. The conclusions of this study indicate that it is possible to cultivate soybean in lowlands after developing the proper soil preparation. Consequently, the yields are increased, and grains will benefit from higher protein and oil contents, enhancing soybean quality for commercialization. Full article

Pulmonary artery endothelial cells (PAECs) are a major contributor to hypoxic pulmonary hypertension (PH) due to the possible roles of reactive oxygen species (ROS). However, the molecular mechanisms and functional roles of ROS in PAECs are not well established. In this study, we first used Amplex UltraRed reagent to assess hydrogen peroxide (H₂O₂) generation. The result indicated that hypoxic exposure resulted in a significant increase in Amplex UltraRed-derived fluorescence (i.e., H₂O₂ production) in human PAECs. To complement this result, we employed lucigenin as a probe to detect superoxide (O₂⁻) production. Our assays showed that hypoxia largely increased O₂⁻ production. Hypoxia also enhanced H₂O₂ production in the mitochondria from PAECs. Using the genetically encoded H₂O₂ sensor HyPer, we further revealed the hypoxic ROS production in PAECs, which was fully blocked by the mitochondrial inhibitor rotenone or myxothiazol. Interestingly, hypoxia caused an increase in the migration of PAECs, determined by scratch wound assay. In contrast, nicotine, a major cigarette or e-cigarette component, had no effect. Moreover, hypoxia and nicotine co-exposure further increased migration. Transfection of lentiviral shRNAs specific for the mitochondrial Rieske iron–sulfur protein (RISP), which knocked down its expression and associated ROS generation, inhibited the hypoxic migration of PAECs. Hypoxia largely increased the proliferation of PAECs, determined using Ki67 staining and direct cell number accounting. Similarly, nicotine caused a large increase in proliferation. Moreover, hypoxia/nicotine co-exposure elicited a further increase in cell proliferation. RISP knockdown inhibited the proliferation of PAECs following hypoxia, nicotine exposure, and hypoxia/nicotine co-exposure. Taken together, our data demonstrate that hypoxia increases RISP-mediated mitochondrial ROS production, migration, and proliferation in human PAECs; nicotine has no effect on migration, increases proliferation, and promotes hypoxic proliferation; the effects of nicotine are largely mediated by RISP-dependent mitochondrial ROS signaling. Conceivably, PAECs may contribute to PH via the RISP-mediated mitochondrial ROS. Full article

Sulfur is a critical element for plant growth and development, serving as a component of amino acids (cysteine and methionine), iron–sulfur clusters, proteins, glutathione, coenzymes, and auxin precursors. Deficiency or low concentrations of sulfur in the soil can lead to significant growth retardation in plants. The objective of our study was to examine the effects of sulfur (S) deficiency and excess on morphological symptoms, sulfur and nitrogen (N) metabolism, as well as antioxidant activity in soybean. We found that S starvation decreased the fine root length, biomass, and activity, and the chlorophyll content was reduced, while excess sulfur promotes lateral root growth. In contrast to sulfur excess, sulfur deficiency inhibits N and S metabolism levels in both subsurface and above-ground parts, and induced the expression of some sulfur transporters (SULTRs). In this study, we created soybean hairy root lines overexpressing the SULTR gene (GmSULTR2;1a) to observe metabolic changes following sulfur deficiency treatment. The results showed that GmSULTR2;1a saved the sulfur-deficient phenotype, and the antioxidant enzyme activity was much higher than that of the wildtype in the absence of sulfur. Our study revealed the important role of sulfur element in soybean growth and development and the regulation of sulfur deficiency by GmSULTR2;1a. Full article