Project description:Rotor syndrome is an autosomal recessive disorder characterized by conjugated hyperbilirubinemia, near-absent hepatic uptake of anionic diagnostics, and coproporphyrinuria. The mechanistic basis of other hyperbilirubinemia syndromes is largely understood, but that of Rotor syndrome has remained enigmatic. The existing paradigm of hepatic bilirubin excretion postulates a unidirectional elimination pathway: Uptake of conjugated bilirubin from blood by hepatocytes, glucuronidation of bilirubin, and excretion of conjugated bilirubin into bile by ABCC2, a canalicular bilirubin-glucuronide and xenobiotic export pump. An analogous view holds for drugs conjugated in the liver. Here we demonstrate by molecular-genetic analysis of 8 Rotor-syndrome families that Rotor syndrome is a two-gene disorder, with impaired hepatic re-uptake of bilirubin-glucuronide caused by complete deficiencies in the hepatic organic anion transporting polypeptides OATP1B1 and OATP1B3.
Project description:The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:Neonatal hyperbilirubinemia (jaundice) is common in infants, with extremely preterm infants (EPT, <28 weeks gestational age) being at high risk for bilirubin-induced neurotoxicity, resulting in neurodevelopmental impairment. Hyperbilirubinemia is treated using phototherapy to lower unconjugated bilirubin levels. However, the benefits and risks of phototherapy in EPTs have not been well studied, and bilirubin at low levels may be protective as an antioxidant. Phototherapy is associated with markers of oxidative stress in the plasma, but the effects of phototherapy on the hippocampus (HPC) are not known. Bilirubin and insults associated with EPTs impair hippocampal development, a brain structure critical for cognitive function, but their underlying mechanisms remain unknown. The effects of hyperbilirubinemia and phototherapy on the HPC were studied using a Gunn rat model. Jaundiced (jj) and non-jaundiced (Nj) pups were subjected to phototherapy from postnatal day 4 (P4) through P6. The HPC was harvested and processed for RNA sequencing. Serum bilirubin levels were elevated in jj compared to Nj control rats. Phototherapy significantly lowered serum bilirubin levels in jj rats. Compared to Nj rats, 1294 genes were differentially expressed in the jj hippocampal transcriptome and mapped onto the nervous system development, inflammation, and ferroptosis signaling pathways. Phototherapy induces 3297 differentially-expressed genes (DEGs) in rat hippocampal transcriptome compared to untreated rats. These DEGs were annotated to pathways regulating synaptogenesis, long-term potentiation, and neurogenesis. Both hyperbilirubinemia and phototherapy altered expression of 407 genes, which mapped onto hippocampal plasticity functions, including neuritogenesis and long-term potentiation. Our study demonstrates a model for investigating molecular effects of hyperbilirubemia and phototherapy in an EPT-equivalent Gunn rat pup. Our data revealed the effects of hyperbilirubinemia and phototherapy on signaling pathways critical for hippocampal development and plasticity.
Project description:Severe presentations of malaria, arising from Plasmodium spp. infection, are often associated with accumulation of circulating bilirubin, a condition known as hyperbilirubinemia or jaundice of malaria. Whether this represents an adaptive or maladaptive response to Plasmodium spp. infection is not understood. Departing from the textbook view of hyperbilirubinemia reflecting a failure to excrete bilirubin, we demonstrate that bilirubin production by biliverdin reductase A (BLVRA) partakes in a host adaptive response to malaria. Genetic Blvra deletion exacerbated malaria mortality in mice; This was associated with a >10-fold increase in parasite burden, compared to control mice expressing BLVRA, which cleared the parasite and survived malaria. At concentrations in the range of jaundice of malaria, unconjugated bilirubin arrested the proliferation and killed asexual blood stages of the human-infective P. falciparum in vitro. This was associated with disruption of the parasite’s mitochondrion and food vacuole as well as with the accumulation of hemozoin in the parasite’s cytoplasm. Moreover, bilirubin inhibited hemozoin (β-hematin) synthesis in vitro, a vital heme-detoxifying pathway targeted by Quinoline-based antimalarial drugs such as chloroquine. In conclusion, hyperbilirubinemia represents an evolutionary conserved metabolite-based resistance mechanism against malaria.
Project description:Tail fat in sheep (Ovis aries), has evolved mainly in response to cold weather for better energy storage. As things stand, too much tail fat in sheep can lead to a reduction in feed utilisation and is also unpopular with consumers due to the excessive fat content in the tail of sheep. Therefore, the need to find the mechanism of tail fat formation is obvious. In this study, we elected to utilise Kazakh sheep, prolific Suffolk sheep, and their hybrid F2 generation as research objects. Sheep transcriptome sequencing technology was employed to screen and explore target candidate genes related to sheep tail fat deposition. Comparison with RNA-seq data from fat-tailed and thin-tailed tissue, the LncRNA-mRNA-miRNA axis was identified as main functional pathway in the formation of fat in tail. Our results offer valuable insights into the fat deposition of sheep and provide a significant genomic resource for future genetic studies and the enhancement of genome-assisted breeding in sheep and other domestic animals.
Project description:The sheep (Ovis aries) plays a major socio-economic role in the world. Copy number variations (CNVs) are increasingly recognized as a key and potent source of genetic variation and phenotypic diversity, but little is known about the extent to which CNVs contribute to genetic variation in Chinese sheep breeds. Analyses of CNVs in the genomes of eight sheep breeds were performed using the sheep SNP50 BeadChip genotyping array. A total of 111 CNV regions (CNVRs) were obtained from 160 Chinese sheep breeds. These CNVRs covered 13.75 Mb of the sheep genome sequence. A total of 22 Go terms and 17 candidate genes were obtained from the functional analysis. Ten CNVRs were selected for validation, of which 7 CNVRs were further experimentally confirmed by quantitative PCR. Four candidate genes were selected to confirm the results of the functional analysis. These results provide a resource for furthering understanding of ruminant biology, and for further improving the genetic quality of sheep breeds.
Project description:We carried out a cross species cattle-sheep array comparative genome hybridization (aCGH) experiment in order to identify copy number variations (CNVs) in the sheep genome analysing animals of Italian dairy breeds (Sarda, Bagnolese, Laticauda, Massese and Valle del Belice) using a tiling oligonucleotide array with ~385,000 probes designed on the bovine genome. We identified 135 CNV regions (CNVRs) covering about 10.5 Mb of the virtual sheep genome referred to the bovine genome (0.398%) with a mean and median equal to 77.6 kb and 55.9 kb, respectively. A comparative analysis between the identified sheep CNVRs and those reported in the cattle and goat genomes indicated that overlaps between sheep and goat and sheep and cattle CNVRs are highly significant (P<0.0001) suggesting that several chromosome regions might contain recurrent interspecies CNVRs. Many sheep CNVs affect genes with important biological functions. Further studies are needed to evaluate the functional relevance of these CNVs.