Low-density lipoprotein receptor-related protein 1(LRP1)is a multifunctional endocytic receptor whose dysfunction is linked to developmental dysplasia of the hip,osteoporosis and osteoarthritis.Our work addresses the ...Low-density lipoprotein receptor-related protein 1(LRP1)is a multifunctional endocytic receptor whose dysfunction is linked to developmental dysplasia of the hip,osteoporosis and osteoarthritis.Our work addresses the critical question of how these skeletal pathologies emerge.Here,we show the abundant expression of LRP1 in skeletal progenitor cells at mouse embryonic stage E10.5 and onwards,especially in the perichondrium,the stem cell layer surrounding developing limbs essential for bone formation.Lrp1 deficiency in these stem cells causes joint fusion,malformation of cartilage/bone template and markedly delayed or lack of primary ossification.展开更多
Alkaptonuria (AKU) is an inherited disorder of tyrosine metabolism caused by lack of active enzyme homogentisate 1,2-dioxygenase (HGD). The primary consequence of HGD deficiency is increased circulating homogentisic a...Alkaptonuria (AKU) is an inherited disorder of tyrosine metabolism caused by lack of active enzyme homogentisate 1,2-dioxygenase (HGD). The primary consequence of HGD deficiency is increased circulating homogentisic acid (HGA), the main agent in the pathology of AKU disease. Here we report the first metabolomic analysis of AKU homozygous Hgd knockout (Hgd−/−) mice to model the wider metabolic effects of Hgd deletion and the implication for AKU in humans. Untargeted metabolic profiling was performed on urine from Hgd−/− AKU (n = 15) and Hgd+/− non-AKU control (n = 14) mice by liquid chromatography high-resolution time-of-flight mass spectrometry (Experiment 1). The metabolites showing alteration in Hgd−/− were further investigated in AKU mice (n = 18) and patients from the UK National AKU Centre (n = 25) at baseline and after treatment with the HGA-lowering agent nitisinone (Experiment 2). A metabolic flux experiment was carried out after administration of 13C-labelled HGA to Hgd−/−(n = 4) and Hgd+/−(n = 4) mice (Experiment 3) to confirm direct association with HGA. Hgd−/− mice showed the expected increase in HGA, together with unexpected alterations in tyrosine, purine and TCA-cycle pathways. Metabolites with the greatest abundance increases in Hgd−/− were HGA and previously unreported sulfate and glucuronide HGA conjugates, these were decreased in mice and patients on nitisinone and shown to be products from HGA by the 13C-labelled HGA tracer. Our findings reveal that increased HGA in AKU undergoes further metabolism by mainly phase II biotransformations. The data advance our understanding of overall tyrosine metabolism, demonstrating how specific metabolic conditions can elucidate hitherto undiscovered pathways in biochemistry and metabolism.展开更多
基金The Andor dragonfly Spinning Disk microscope in the CCI was funded by the BBSRC(BB/R01390X/1)This work was supported by the ministry of education of the Kingdom of Saudi Arabia(to M.Alhashmi)+6 种基金Libyan Ministry of Higher Education and Scientific Research and ECMage(to A.M.E.Gremida)Qatar National Research Fund(to N.A.Al-Maslamani)European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement(860635 to M.Antonaci and A.Kerr)BBSRC Grants(BB/T00715X/1 to S.K.Maharana and G.N.WheelerBB/X000907/1 to D.A.Turner)Versus Arthritis Career Development Fellowship(21447 to K.Yamamoto)Versus Arthritis Bridging Fellowship(23137 to K.Yamamoto).
文摘Low-density lipoprotein receptor-related protein 1(LRP1)is a multifunctional endocytic receptor whose dysfunction is linked to developmental dysplasia of the hip,osteoporosis and osteoarthritis.Our work addresses the critical question of how these skeletal pathologies emerge.Here,we show the abundant expression of LRP1 in skeletal progenitor cells at mouse embryonic stage E10.5 and onwards,especially in the perichondrium,the stem cell layer surrounding developing limbs essential for bone formation.Lrp1 deficiency in these stem cells causes joint fusion,malformation of cartilage/bone template and markedly delayed or lack of primary ossification.
基金BPN is funded by the University of Liverpool,Royal Liverpool University Hospitals Trust and Agilent Technologies UK Ltd.ASD is funded through a National Institute for Health Research Doctoral Research Fellowship(No.HCS DRF-2014-05-009).
文摘Alkaptonuria (AKU) is an inherited disorder of tyrosine metabolism caused by lack of active enzyme homogentisate 1,2-dioxygenase (HGD). The primary consequence of HGD deficiency is increased circulating homogentisic acid (HGA), the main agent in the pathology of AKU disease. Here we report the first metabolomic analysis of AKU homozygous Hgd knockout (Hgd−/−) mice to model the wider metabolic effects of Hgd deletion and the implication for AKU in humans. Untargeted metabolic profiling was performed on urine from Hgd−/− AKU (n = 15) and Hgd+/− non-AKU control (n = 14) mice by liquid chromatography high-resolution time-of-flight mass spectrometry (Experiment 1). The metabolites showing alteration in Hgd−/− were further investigated in AKU mice (n = 18) and patients from the UK National AKU Centre (n = 25) at baseline and after treatment with the HGA-lowering agent nitisinone (Experiment 2). A metabolic flux experiment was carried out after administration of 13C-labelled HGA to Hgd−/−(n = 4) and Hgd+/−(n = 4) mice (Experiment 3) to confirm direct association with HGA. Hgd−/− mice showed the expected increase in HGA, together with unexpected alterations in tyrosine, purine and TCA-cycle pathways. Metabolites with the greatest abundance increases in Hgd−/− were HGA and previously unreported sulfate and glucuronide HGA conjugates, these were decreased in mice and patients on nitisinone and shown to be products from HGA by the 13C-labelled HGA tracer. Our findings reveal that increased HGA in AKU undergoes further metabolism by mainly phase II biotransformations. The data advance our understanding of overall tyrosine metabolism, demonstrating how specific metabolic conditions can elucidate hitherto undiscovered pathways in biochemistry and metabolism.
