Oxidative Phosphorylation Pathway Genes Research Articles

Mitochondrial dysfunction induced by bedaquiline as an anti-Toxoplasma alternative

Toxoplasma gondii is a zoonotic parasite that infects one-third of the world’s population and nearly all warm-blooded animals. Due to the complexity of T. gondii’s life cycle, available treatment options have limited efficacy. Thus, there is an urgent need to develop new compounds or repurpose existing drugs with potent anti-Toxoplasma activity. This study demonstrates that bedaquiline (BDQ), an FDA-approved diarylquinoline antimycobacterial drug for the treatment of tuberculosis, potently inhibits the tachyzoites of T. gondii. At a safe concentration, BDQ displayed a dose-dependent inhibition on T. gondii growth with a half-maximal effective concentration (EC50) of 4.95 μM. Treatment with BDQ significantly suppressed the proliferation of T. gondii tachyzoites in the host cell, while the invasion ability of the parasite was not affected. BDQ incubation shrunk the mitochondrial structure and decreased the mitochondrial membrane potential and ATP level of T. gondii parasites. In addition, BDQ induced elevated ROS and led to autophagy in the parasite. By transcriptomic analysis, we found that oxidative phosphorylation pathway genes were significantly disturbed by BDQ-treated parasites. More importantly, BDQ significantly reduces brain cysts for the chronically infected mice. These results suggest that BDQ has potent anti-T. gondii activity and may impair its mitochondrial function by affecting proton transport. This study provides bedaquiline as a potential alternative drug for the treatment of toxoplasmosis, and our findings may facilitate the development of new effective drugs for the treatment of toxoplasmosis.

Transcriptomic Analysis of Three Differentially Senescing Maize (Zea mays L.) Inbred Lines upon Heat Stress.

Maize, one of the world's major food crops, is facing the challenge of rising temperature. Leaf senescence is the most significant phenotypic change of maize under heat stress at the seedling stage, but the underlying molecular mechanism is still unknown. Here, we screened for three inbred lines (PH4CV, B73, and SH19B) that showed differentially senescing phenotypes under heat stress. Among them, PH4CV showed no obviously senescing phenotype under heat stress, while SH19B demonstrated a severely senescing phenotype, with B73 being between the two extremes. Subsequently, transcriptome sequencing showed that differentially expressed genes (DEGs) were generally enriched in response to heat stress, reactive oxygen species (ROS), and photosynthesis in the three inbred lines under heat treatment. Notably, ATP synthesis and oxidative phosphorylation pathway genes were only significantly enriched in SH19B. Then, the expression differences of oxidative phosphorylation pathways, antioxidant enzymes, and senescence-related genes in response to heat stress were analyzed in the three inbred lines. In addition, we demonstrated that silencing ZmbHLH51 by virus-induced gene silencing (VIGS) inhibits the heat-stress-induced senescence of maize leaves. This study helps to further elucidate the molecular mechanisms of heat-stress-induced leaf senescence at the seedling stage of maize.

Isoimperatorin: A promising anti Gyrodactylus kobayashii natural compound from Angelica dahurica

Current gyrodactylids treatments using chemicals such as rotenone, piperazine and trichlorfon cause environmental and human health issues, especially their toxicity to the host. Therefore, search for alternative anthelmintic agents is urgent and natural compounds from herbs show promising solution to this problem. In our previous study, we screened 33 herbal medicines and found that Angelica dahurica has a good anthelmintic efficacy. In order to identify the active compounds from Angelica dahurica, bioassay-guided isolation was performed using a Carassius auratus - Gyrodactylus kobayashii model in this study. After extraction, purification and characterization step by step, isoimperatorin was eventually separated as the main active ingredient for eradicating G. kobayashii in goldfish. Compared to the control groups, bathing G. kobayashii-infected goldfish in isoimperatorin significantly reduced infection prevalence and intensity, with EC50 values of 0.63 (24 h) and 0.53 mg/L (48 h), respectively. Acute toxicity assays indicated that the LC50 (96 h) of isoimperatorin against goldfish was 10.16 mg/L, which was 19.17 times higher than EC50 (48 h). In addition, scanning electron microscope (SEM) and RT-qPCR were used to explore the anthelminthic mechanism of isoimperatorin. TEM results showed that after exposure to isoimperatorin, morphological alterations in the tegument of G. kobayashii were observed, which disrupted its homeostasis. Besides, isoimperatorin significantly downregulated the expression of ATPase genes (ATP5A1, ATP5C, ATP5F) and oxidative phosphorylation pathway genes (NDUFS8, NDUFA8, SDH). After treatment with isoimperatorin, the content of ATP in the worms decreased significantly. In summary, isoimperatorin showed promising anti G. kobayashii efficacy via damaging tegument, supplying insufficient energy to the G. kobayashii.

Lysine-specific histone demethylase 1 inhibition promotes reprogramming by facilitating the expression of exogenous transcriptional factors and metabolic switch.

Lysine-specific histone demethylase 1 (LSD1) regulates histone methylation and influences the epigenetic state of cells during the generation of induced pluripotent stem cells (iPSCs). Here we reported that LSD1 inhibition via shRNA or specific inhibitor, tranylcypromine, promoted reprogramming at early stage via two mechanisms. At early stage of reprogramming, LSD1 inhibition increased the retrovirus-mediated exogenous expression of Oct4, Klf4, and Sox2 by blocking related H3K4 demethylation. Since LSD1 inhibition still promoted reprogramming even when iPSCs were induced with small-molecule compounds in a virus-free system, additional mechanisms should be involved. When RNA-seq was used for analysis, it was found that LSD1 inhibition reversed some gene expression changes induced by OKS, which subsequently promoted reprogramming. For example, by partially rescuing the decreased expression of Hif1α, LSD1 inhibition reversed the up-regulation of genes in oxidative phosphorylation pathway and the down-regulation of genes in glycolysis pathway. Such effects facilitated the metabolic switch from oxidative phosphorylation to glycolysis and subsequently promoted iPSCs induction. In addition, LSD1 inhibition also promoted the conversion from pre-iPSCs to iPSCs by facilitating the similar metabolic switch. Therefore, LSD1 inhibition promotes reprogramming by facilitating the expression of exogenous transcriptional factors and metabolic switch.

Gene Expression Profiling Differentiates Childhood Acute Lymphoblastic Leukemia in Down Syndrome Versus Non-Down Syndrome Patients.

Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) form a unique biological subset. These patients have generally inferior outcomes in many studies, and an increased incidence of treatment-related toxicities. Cases of DS ALL have a much lower frequency of recurrent prognostically significant chromosomal abnormalities than cases of ALL in the general pediatric population. Global gene expression profiling provides an opportunity to gain insights into pathogenesis and potential therapeutic targets in DS ALL. We performed microarray analysis of RNA from bone marrow samples obtained at diagnosis in 30 DS ALL and 24 non-DS ALL cases using the Affymetrix Human Genome U133 Plus 2.0 array. Unsupervised hierarchical clustering separated cases into two main groups, one of which included 21 of 30 DS samples (Fisher's exact test, p = 0.013), suggesting inherent biologic similarities. Non-DS samples clustered according to known cytogenetic features. Consistent with recently published data, a subset (13%) of our DS ALL cases were found to have JAK2 mutations. Cases of DS ALL bearing JAK2 mutations did not form a distinct subcluster, suggesting that the JAK2 pathway may be dysregulated via other events in cases of DS ALL with wild-type JAK2. Two-sample comparison of DS versus non-DS ALL cases demonstrated differential expression of 513 genes with p values <0.001 (Figure 1). Oxidative phosphorylation pathway genes were most over-represented among differentially expressed genes, with 35 of 115 genes in this pathway demonstrating down-regulation in DS compared to non-DS ALL (Bonferroni corrected p value < 1 ×10−9), including several cytochrome c oxidase and ubiquinone subunits. Our data indicate that DS ALL blasts may utilize oxidative phosphorylation to a lesser extent than non-DS ALL, a feature which could be exploited therapeutically.The top 513 genes differentially expressed in DS versus non-DS ALL (Benjamini-Hochberg corrected p values < 0.001) are displayed in a heatmap where genes relatively overexpressed in DS ALL are depicted in yellow, and relatively underexpressed in DS ALL in red. DS ALL cases are indicated by red circles and non-DS ALL cases by white circles. Four DS ALL cases bearing a JAK2 mutation at arginine 683 are indicated by black stars. [Display omitted]