Project description:Kidneys from a male and female mouse were used for single nucleus isolation and transcriptome analyses using the 10X Genomics platform.
Project description:Ammonia is a toxic by-product of metabolism that causes cellular stress. Although a number of proteins are involved in adaptive stress response, specific factors that counteract ammonia-induced cellular stress and regulate cell metabolism that facilitate survival against toxicity have yet to be identified. We demonstrated that hypoxia-inducible factor-1α (HIF-1α) is stabilised and activated by ammonia stress. HIF-1α activated by ammonium chloride compromises ammonia-induced apoptosis. Furthermore, we identified glutamine synthetase (GS) as a key driver of cancer cell proliferation and glutamine-dependent metabolism under ammonia stress in ovarian cancer stem-like cells expressing CD90. Interestingly, activated HIF-1α counteracts glutamine synthetase function in glutamine metabolism by facilitating glycolysis and elevating glucose dependency. Our studies reveal the hitherto unknown functions of HIF-1α in biphasic ammonia stress management in cancer stem-like cells. GS facilitates proliferation and HIF-1α contributes to metabolic remodelling in cellular energy usage resulting in attenuated proliferation but conversely promoting cell survival.
Project description:Circadian rhythmicity in renal function suggests rhythmic adaptations in renal metabolism. To decipher the role of the circadian clock in renal metabolism, we studied diurnal changes in renal metabolic pathways using integrated transcriptomic, proteomic, and metabolomic analysis performed on control mice and mice with inducible deletion of the circadian clock regulator Bmal1 in the renal tubule (cKOt). With this unique resource, we demonstrated that ~30% RNAs, ~20% proteins and ~20% metabolites are rhythmic in kidneys of control mice. Several key metabolic pathways including NAD+ biosynthesis, fatty acid transport, carnitine shuttle, and b-oxidation displayed impairments in kidneys of cKOt, resulting in a perturbed mitochondrial activity. Carnitine reabsorption from the primary urine was one of the most impacted processes with a ~50% reduction in plasma carnitine levels and a parallel systemic decrease in tissues carnitine content. This suggests that the circadian clock in the renal tubule controls both kidney and systemic physiology.
Project description:The abundance of bacterial (AOB) and archaeal (AOA) ammonia oxidisers, assessed using quantitative PCR measurements of their respective a-subunit of the ammonia monooxygenase (amoA) genes, and ammonia oxidation rates were measured in four contrasting coastal sediments in the Western English Channel. Sediment was sampled bimonthly from July 2008 to May 2011, and measurements of ammonia oxidiser abundance and activity compared to a range of environmental variables including salinity, temperature, water column nutrients and sediment carbon and nitrogen content. Despite a higher abundance of AOA amoA genes within all sediments, and at all time-points, rates of ammonia oxidation correlated with AOB and not AOA amoA gene abundance. Other than ammonia oxidation rate, sediment particle size was the only variable that correlated with the spatial and temporal patterns of AOB amoA gene abundance, implying a preference of the AOB for larger sediment particles. This is possibly due to deeper oxygen penetration into the sandier sediments, increasing the area available for ammonia oxidation to occur, higher concentrations of inhibitory sulphide with pore waters of muddier sediments or a combination of both oxygen and sulphide concentrations. Similar to many other temporal studies of nitrification within estuarine and coastal sediments, decreases in AOB amoA gene abundance were evident during summer and autumn, with maximum abundance and ammonia oxidation rates occurring in winter and early spring. The lack of correlation between AOA amoA gene abundance and ammonium oxidation rate suggests an alternative role for amoA-carrying AOA within these sediments.
Project description:The liver is the largest detoxification organ in the human body. RNA sequencing (RNA-seq) analyses of liver samples were performed to investigate the effects of high ammonia levels (ammonia exposure at 75 ± 5 ppm), a low ammonia level (ammonia exposure at 5 ± 5 ppm) was set as control group, on the metabolism and detoxification capabilities of laying ducks.
Project description:Abstract: Ammonia is one of the most prominent air pollutants in poultry houses. High levels of ammonia have adverse effects on respiratory health, growth performance, meat production of broilers, and breast meat growth and yield are critical important in the broiler industry. To date, studies focus on the negative relationship of ammonia exposure and breast muscle tissue are still very limited, and the underlying molecular mechanisms remain poorly understood. In this study, high concentrations of atmospheric ammonia were found to lower slaughter rate and broiler breast meat yield significantly (P < 0.05). To explore the candidate genes that ammonia regulates breast meat yield of broilers, high throughout RNA-Seq was used to compare the transcriptome of breast muscle with different ammonia exposure (50 ppm vs 3 ppm). In total, 129 differentially expressed genes (DEGs) were identified (P-value < 0.05; fold-change ≥ 2), among which 87 genes were significantly down-regulated and 42 were up-regulated. Bioinformatics analysis suggested that DEGs (such as PDK4, ACSL1, GLUL, FBXO32) were involved in fatty acid degradation/metabolism, nitrogen metabolism, PPAR signaling and adipocytokine signaling pathways. Functional annotation showed that DEGs were mainly enriched in reactive oxygen species metabolic process and muscle contraction. It can be concluded that decreased meat yield was due to the DEGs participating in above biological processes and pathways. This study provides novel insights into transcriptional differences in breast meat between high- and low-ammonia exposed broiler chickens.
Project description:The abundance of bacterial (AOB) and archaeal (AOA) ammonia oxidisers, assessed using quantitative PCR measurements of their respective a-subunit of the ammonia monooxygenase (amoA) genes, and ammonia oxidation rates were measured in four contrasting coastal sediments in the Western English Channel. Sediment was sampled bimonthly from July 2008 to May 2011, and measurements of ammonia oxidiser abundance and activity compared to a range of environmental variables including salinity, temperature, water column nutrients and sediment carbon and nitrogen content. Despite a higher abundance of AOA amoA genes within all sediments, and at all time-points, rates of ammonia oxidation correlated with AOB and not AOA amoA gene abundance. Other than ammonia oxidation rate, sediment particle size was the only variable that correlated with the spatial and temporal patterns of AOB amoA gene abundance, implying a preference of the AOB for larger sediment particles. This is possibly due to deeper oxygen penetration into the sandier sediments, increasing the area available for ammonia oxidation to occur, higher concentrations of inhibitory sulphide with pore waters of muddier sediments or a combination of both oxygen and sulphide concentrations. Similar to many other temporal studies of nitrification within estuarine and coastal sediments, decreases in AOB amoA gene abundance were evident during summer and autumn, with maximum abundance and ammonia oxidation rates occurring in winter and early spring. The lack of correlation between AOA amoA gene abundance and ammonium oxidation rate suggests an alternative role for amoAÂ-carrying AOA within these sediments. Two color array (Cy3 and Cy5): the universal standard 20-mer oligo is printed to the slide with a 70-mer oligo (an archetype). Environmental DNA sequences (fluoresced with Cy3) within 15% of the 70-mer conjugated to a 20-mer oligo (fluoresced with Cy5) complementary to the universal standard will bind to the oligo probes on the array. Signal is the ratio of Cy3 to Cy5. Three replicate probes were printed for each archetype. Two replicate arrays were run on duplicate targets.
Project description:Different segments of renal tubules have distinct metabolic features and functions, and defective metabolism in renal tubules is involved in the pathobiology of kidney diseases. However, the mechanisms underlying the metabolic regulation in renal tubules remain to be defined. We demonstrated that the renal proximal tubule (PT) has high expression of fatty acid and lipid metabolism enzymes, which is transcriptionally upregulated by abundantly expressed peroxisome proliferator-activated receptor (PPAR)/γ to support active lipid metabolism. In contrast, the renal distal tubule (DT) has elevated glycolytic enzyme expression corresponding with high rates of glycolysis, and this increased expression is mediated by abundantly expressed c-Myc. In addition, Nrf2 upregulated glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-dependent malic enzyme 1 expression for NADPH production and antioxidation in the DT. Highly expressed PPARγ transcriptionally enhanced expression of the protease iRhom2 in the PT, which suppressed epidermal growth factor (EGF) expression and secretion, inhibiting EGF receptor activation-dependent glycolytic gene expression and maintaining the low level of glycolysis. PPARγ inhibition reduced iRhom2 expression and increased EGF and GLUT1 expression in the PT in mice, resulting in hypertrophy of renal tubules and inhibited kidney functions, which can be rescued by inhibition of glycolysis via treatment with 2-deoxy-D-glucose. These findings delineate instrumental molecular mechanisms underlying the active lipid metabolism and suppressed glycolysis in the PT and active glycolysis in the DT and reveal critical roles for PPARs and c-Myc in maintaining metabolic homeostasis in the kidney