Project description:Manganese (Mn) stress is known to be a major limitation for development of soybean, and legume crop productivity globally. However, very little information is available on the adaptive mechanisms, particularly in the important legume crop soybean (Glycine Max L.), which enable leaves to respond to high-Mn availability. Thus, to elucidate these mechanisms in soybean leaves at molecular level, we used an RNA sequencing approach to investigate transcriptomes of the leaves under Mn-sufficient and Pi-excessive conditions. Our investigation revealed that more genes showed altered expression patterns in old leaf than in young leaf under Mn excess, suggesting that the Mn excess-more-sensitive old leaf required expression change in a larger number of genes to cope with high-Mn stress than the Mn excess-less-sensitive young leaf. The functional classification of differentially expressed genes (DEGs) was examined to gain an understanding of how leaves respond to Mn stress, caused by soil Mn excess. As a result, more DEGs involved in nodulation, detoxification, nutrient/ion transport, transcriptional factors, key metabolic pathways, Mn remobilization and signalling were found in Mn-excessive induced old leaves than in Mn-excessive induced young leaves. Our findings have enabled the identification of molecular processes that play important roles in the acclimation of leaves to Mn excess, ultimately leading to the development of Mn-efficient soybean suitable for Mn-excessive soils.
Project description:Idiopathic Parkinson’s disease (iPD) and manganese-induced atypical Parkinsonism are characterized by movement disorder and nigrostriatal pathology. Although clinical features, brain region involved and responsiveness to L-DOPA differentiate both, the differences at the neuronal level are largely unknown. We investigated the morphological, physiological and molecular differences in dopaminergic neurons exposed to the PD toxin 1-methyl-4-phenylpyridinium ion (MPP+) and manganese (Mn). While Mn was neurotoxic at lower dose, MPP+ toxicity entailed oxidative damage, mitochondria dysfunction and glycolytic shift. Morphological analysis highlighted mitochondrial damage, while morphometric analysis indicated loss of neuronal processes in the MPP+ model and not in the Mn model. Elecrophysiological analysis demonstrated lower number of spikes and firing frequency in MPP+ treated cells, while it was unchanged in the Mn model. High throughput transcriptomic analysis revealed upregulation of 694 and 603 genes and down-regulation of 428 and 255 genes in the MPP+ and Mn models respectively. Many differentially expressed genes were unique to either models and contributed to neuroinflammation, metabolic and mitochondrial function, apoptosis and nuclear function, synaptic plasticity, neurotransmission and cytoskeletal architecture. Analysis of the JAK-STAT pathway with implications for neuritogenesis, neuronal proliferation and nuclear function revealed contrasting profile between Mn and MPP+ models. Genome-wide DNA methylation profile revealed significant differences between both models and substantiated the epigenetic basis of the difference in the JAK-STAT pathway. We conclude that iPD and atypical Parkinsonism represent a divergent neurotoxicological manifestation at the dopaminergic neuronal level with implications for pathobiology and to evolve novel therapeutics
Project description:Behavioral deficits encompassing motor, cognitive, and psychological domains can emerge after removal of manganese (Mn) exposures in humans and other mammals. While epidemiological studies provide substantial evidence supporting latent persistent Mn neurotoxicity, reproducing such effects in cellular and non-mammalian model systems has slowed mechanistic understanding. Here we report in human induced pluripotent stem cell (hiPSC)-derived cortical cultures that chronic Mn exposure elicits clear latent and persistent neurotoxic effects in gene expression and functional outcomes. To identify persistent and latent effects, and investigate underlying mechanisms, single-cell RNA sequencing was employed in the hiPSC model to provide a comprehensive cell-type specific comparison of transcriptomic changes immediately at the termination versus after a prolonged cessation of chronic Mn exposures. Transcriptomic alterations revealed clear latency of effects after Mn cessation that were not detected immediately following the 40-day exposure. Identified alterations support the linkage between the latent and persistent effects of chronic Mn exposure and a broad range of neurodegenerative pathogenesis and provide insight into the cellular pathways involved.
Project description:We assessed changes in gene expression in response to manganese availability for the human pathogen Corynebacterium diphtheriae. Total RNA was harvested from wild-type C. diphtheriae strain 1737 and an isogenic ΔmntR (dip0619) grown in semi-defined metal-limited media (mPGT) without or with 5 µM manganese chloride supplementation. Three biological replicates were prepared and five genes were assessed by real-time PCR to validate the array results: dip0124, dip0169, dip0615, dip1923, and dip2261. (Abstract) Corynebacterium diphtheriae is the causative agent of a severe respiratory disease in humans. The bacterial systems required for infection are poorly understood, but the acquisition of metals such as manganese (Mn) are likely critical for host colonization. MntR is a Mn-dependent transcriptional regulator in C. diphtheriae and was previously shown to repress the expression of the mntABCD genes, which encode an ABC metal transporter. However, other targets of Mn and MntR regulation in C. diphtheriae have not been identified. In this study, we use comparisons between the gene expression profiles of wild-type C. diphtheriae strain 1737 grown without or with Mn supplementation and comparisons of gene expression between wild-type and an mntR mutant to characterize the C. diphtheriae Mn and MntR regulon. MntR was observed to both repress and induce the expression of various target genes in a Mn-dependent manner. Genes induced by MntR include the Mn-superoxide dismutase, sodA, and the putative ABC transporter locus, iutABCD. DNA binding studies showed that MntR interacts at the promoter regions for several genes identified in the expression study, and a 17-bp consensus MntR DNA binding site was identified. We found that an mntR mutant displayed increased sensitivity to Mn and Cd that could be alleviated by the additional deletion of the mntA-D transport locus, providing evidence that the MntABCD transporter functions as a Mn uptake system in C. diphtheriae. The findings in this study further our understanding of metal uptake systems and global metal regulatory networks in this important human pathogen.
Project description:We report the application of RNA-Seq analysis to determine the transcriptional responses to Mn dose, ranging from physiological to toxicological levels in human SH-SY5Y neuroblastoma cells. We find that Mn dose showed widespread effects in abundance of protein coding genes for metabolism of reactive oxygen species, energy sensing, glycolysis, protein homeostasis including the unfolded protein response and transcriptional regulation. Adaptive responses at physiological Mn concentration-10 μM Mn for 5 h, a concentration that did not result in cell death after 24 h increased abundance of differentially expressed genes (DEGs) in the protein secretion pathway that function in protein trafficking and cellular homeostasis.These include BET1 (Golgi vesicular membrane trafficking protein), ADAM10 (ADAM metallopeptidase domain 10) and ARFGAP3 (ADP-ribosylation factor GTPase activating protein 3). In contrast, 5 h exposure to 100 μM Mn, a concentration that caused cell death after 24 h, increased abundance of DEGs for components of the mitochondrial oxidative phosphorylation pathway. In conclusion, this study provides a framework for Mn dose dependent exposure in a human in vitro cell culture model and provides a testable hypothesis for in vivo studies. Importantly, the transcriptome responses at toxic Mn dose demonstrated patterns observed with neurological diseases and suggest that differential functions of the secretory pathway and mitochondria could provide a basis to improve detection and management of adverse environmental and occupational Mn exposures.
Project description:Manganese (Mn) is an essential micronutrient critical for the pathogenesis of Staphylococcus aureus, a significant cause of human morbidity and mortality. Paradoxically, excess Mn is toxic, therefore maintaining intracellular Mn homeostasis is required for survival. To identify gene candidates that contribute to manganese detoxification, we compared the transcriptional response of S. aureus cells exposed to 1 mM MnCl2 and those that were untreated.
Project description:Despite its necessity, manganese (Mn) can causes phytotoxicity when present in excess. Stylo (Stylosanthes) is a dominant tropical legume with high Mn adaptability, but its Mn tolerance mechanisms are not well documented. This study integrated both physiological and transcriptome analyses of stylo in response to excess Mn toxicity. Results showed that stylo growth was decreased by excess Mn higher than 200 µM, as reflected by reductions in leaf chlorophyll and plant dry weight. Increases in enzyme activities of peroxidase (POD), ascorbate peroxidase (APX) and phenylalanine ammonia-lyase (PAL) and concentrations of secondary metabolites, including total phenols, flavonoids, tannins and anthocyanidins, were observed in stylo leaves at high Mn stress. Transcriptome analysis in stylo leaves resulted in identification of 2,471 up-regulated and 1,623 down-regulated genes under excess Mn toxicity. Among them, a set of differentially expressed genes (DEGs) involved in secondary metabolism, including PAL, chalcone synthase (CHS), chalcone isomerase (CHI) and flavonol synthase (FLS), were up-regulated in stylo under Mn toxicity, which were closely associated with the accumulation of secondary metabolites, suggesting that activation of secondary metabolism and corresponding gene expression might be important for stylo adaptation to Mn toxicity. Furthermore, a group of DEGs encoding transcription factors, such as genes belonged to C2H2 zinc finger transcription factor, WRKY, MYB and AP2 family, may be involved in stylo responses to Mn toxicity. Taken together, this study suggests that enhancing defense response and secondary biosynthesis pathway is adaptive strategy of stylo during Mn exposure, which might be regulated by complex transcriptional regulatory networks.
Project description:Purpose: Circular RNA sequencing was used to find out differentially expressed CircRNAs between chodrocytes treated with or without cholesterol.Methods:chondrocyte CircRNAs profiles of cholesterol (10ug/ml) treated samples.
Project description:Rats were exposed to manganese (Mn) at 25mg/kg for 15 days. After the exposure, the RNA was collected from the striatum tissue (specific part the brain) of the control group (untreated) and Mn-exposed group, and submitted for RNA sequencing to elucidate the transcriptional changes of Mn-induced toxicity in the striatum.
Project description:Manganese (Mn) is an essential trace element required for various biological functions, but excessive Mn levels are neurotoxic and lead to significant health concerns. The mechanisms underlying Mn-induced neurotoxicity remain poorly understood. Neuropathological studies of affected brain regions reveal astrogliosis, and neuronal loss, along with evidence of neuroinflammation. Here, we present a novel Mn-dependent mechanism linking mitochondrial dysfunction to neuroinflammation. We found that Mn disrupts mitochondrial transcriptome processing, resulting in the accumulation of complementary RNAs that form double-stranded RNA (dsRNA). This dsRNA is released to the cytoplasm, where it activates cytosolic sensor pathways, triggering type I interferon responses and inflammatory cytokine production. This mechanism is evident in 100-day human cerebral organoids, where Mn-induced inflammatory responses are observed predominantly in mature astrocytes. Similar effects were observed in the transcriptome and cytokine profile of female and male mouse brains carrying mutations in the SLC30A10 gene, a model of hypermanganesemia with dystonia1 disorder. These findings highlight a previously unrecognized role for mitochondrial dsRNA in Mn-induced neuroinflammation and provide insights into the molecular pathogenesis of manganism. We propose that this mitochondrial dsRNA-induced inflammatory pathway could be active in other diseases caused by environmental or genetic factors.