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Florence W L Tsui - One of the best experts on this subject based on the ideXlab platform.
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Genetics and Mechanisms of Crystal Deposition in Calcium Pyrophosphate Deposition Disease
Current Rheumatology Reports, 2012Co-Authors: Florence W L TsuiAbstract:Calcium pyrophosphate deposition (CPPD) disease (common in older adults) can be asymptomatic, associated with osteoarthritis, or can present as acute/chronic inflammatory arthritis. Due to the phenotypic complexity of CPPD, the European League Against Rheumatism (EULAR) recently made recommendations on terminology, diagnosis, and management based on available research evidence and expert consensus. There are no disease-modifying treatments for CPPD disease, and therapy remains nonspecific with the use of anti-inflammatory and analgesic drugs. For years, it has been known that inorganic phosphate and pyrophosphate regulate the formation of CPP or hydroxyapatite crystals. The discovery of ANKH (human homologue of progressive ankylosis ) mutations in familial CPPD disease confirmed the importance of phosphate/pyrophosphate homeostasis in CPPD, with ANKH being a regulator of inorganic pyrophosphate transport. Despite progress in our understanding of the function of ANKH, much remains to be investigated. This review summarizes the genetic basis of this disease and focuses on the challenges of research in this area.
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the cppdd associated ANKH m48t mutation interrupts the interaction of ANKH with the sodium phosphate cotransporter pit 1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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The CPPDD-Associated ANKH M48T Mutation Interrupts the Interaction of ANKH with the Sodium/Phosphate Cotransporter PiT-1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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the ANKH δe490mutation in calcium pyrophosphate dihydrate crystal deposition disease cppdd affects tissue non specific alkaline phosphatase tnap activities
The Open Rheumatology Journal, 2008Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Frank Beier, Kenneth P.h. Pritzker, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (ΔE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (ΔE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH ΔE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
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The ANKH DeltaE490Mutation in Calcium Pyrophosphate Dihydrate Crystal Deposition Disease (CPPDD) Affects Tissue Non-specific Alkaline Phosphatase (TNAP) Activities.
The open rheumatology journal, 2008Co-Authors: Frank Beier, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, John Wang, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (DeltaE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (DeltaE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH DeltaE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
Charlene J. Williams - One of the best experts on this subject based on the ideXlab platform.
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Mutations in osteoprotegerin account for the CCAL1 locus in calcium pyrophosphate deposition disease
Osteoarthritis and Cartilage, 2018Co-Authors: Charlene J. Williams, U. Qazi, M. Bernstein, A. Charniak, Claudia M. Gohr, Elizabeth Mitton-fitzgerald, A. Ortiz, L. Cardinal, A.t. Kaell, Ann K. RosenthalAbstract:Summary Objective Mutations on chromosomes 5p (CCAL2) and 8q (CCAL1) have been linked to familial forms of calcium pyrophosphate deposition disease (CPDD). Mutations in the ANKH gene account for CCAL2, but the identity of CCAL1 has been elusive. Recently, a single Dutch kindred with a mutation in the Tumor Necrosis Factor Receptor Super Family member 11B (TNFRSF11B) gene coding for osteoprotegerin (OPG) was described as a gain-of-function mutation. Affected family members had premature generalized osteoarthritis (PGOA) and CPDD. As the TNFRSF11B gene is on 8q, we sought additional evidence that TNFRSF11B was CCAL1, and investigated potential disease mechanisms. Design DNA from two novel PGOA/CPDD families was screened for sequence variants in the TNFRSF11B gene. Mutations were verified by genotype analysis of affected and unaffected family members. We also investigated effects of normal and mutant OPG on regulators of CPP crystal formation in porcine cartilage. Results The identical TNFRSF11B mutation described in the Dutch family was present in two novel PGOA/CPDD families. ANKH was normal in affected patient fibroblasts. Exogenous OPG did not alter ANKH mRNA or protein levels, affect translocation of ANKH to the membrane, nor increase [pyrophosphate (PPi)] or other key regulators of CPDD. Conclusion We have firmly established the identity of CCAL1 as TNFRSF11B (OPG). Our findings suggest that this mutation produces disease in an ANKH-independent manner via novel mechanisms not primarily targeting cartilage. This work rationalizes further investigation of OPG pathway components as potential druggable targets for CPDD.
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Genetics of chondrocalcinosis
Osteoarthritis and Cartilage, 2005Co-Authors: Raihana Zaka, Charlene J. WilliamsAbstract:Summary Rapid developments in genetic analysis have enabled the dissection of a variety of arthropathies that are inherited in a Mendelian manner. These disorders include calcium crystal arthropathies such as calcium pyrophosphate dihydrate deposition (CPPD) disease and hydroxyapatite deposition disease. In CPPD disease, mutations in a recently discovered gene, ANKH, have been demonstrated in five affected families and may also be associated with the idiopathic deposition of calcium pyrophosphate dihydrate crystals. The product of ANKH appears to be involved in cellular transport of inorganic pyrophosphate (PPi) and mutations in ANKH have been shown to have a significant impact on the regulation of intra- and extracellular levels of PPi. In families with hydroxyapatite deposition disease, no gene locus has yet been linked to the disorder.
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mutations in the amino terminus of ANKH in two us families with calcium pyrophosphate dihydrate crystal deposition disease
Arthritis & Rheumatism, 2003Co-Authors: Charlene J. Williams, Adrian Pendleton, Gina Bonavita, Shelly Peariso, Daniel J. Mccarty, Anne E Hughes, Antonio J Reginato, Michael Doherty, Lawrence M. RyanAbstract:Objective To analyze ANKH in families with calcium pyrophosphate dihydrate crystal deposition disease (CPPD) for disease-causing mutations. Methods Two US families (one of British ancestry and the other of German/Swiss ancestry) with autosomal-dominant CPPD, whose disease phenotypes were found to be linked to chromosome 5p15.1 (locus symbol CCAL2), were screened by direct sequencing for mutations in ANKH, a gene in the CCAL2 candidate interval that has been shown to harbor mutations in other families with CPPD. Observed sequence variants were confirmed by antisense sequencing, and expression of the mutant allele was verified by reverse transcriptase–polymerase chain reaction amplification of messenger RNA followed by direct sequencing. Results The two US families displayed the same mutation at position 5 of the ANKH gene product (P5T). All affected members were heterozygous for the P-to-T variant, and the mutation was not seen in 204 control alleles. The two families displayed distinct disease haplotypes, suggesting that they were unrelated to each other. Conclusion These observations represent the fourth and fifth families with heritable CPPD whose disease phenotypes are linked to the CCAL2 locus and who have missense mutations in the amino terminus of ANKH. This same position (P5) was the site of a missense mutation in an Argentinean family of northern Italian ancestry; however, the sequence variant in that family generated a P5L mutation. The distinct disease haplotypes among the 3 families with P5 mutations suggest that the mutations arose independently and that the evolutionarily conserved P5 position of ANKH may represent a hot spot for mutation in families with autosomal-dominant CPPD.
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familial calcium pyrophosphate dihydrate deposition disease and the ANKH gene
Current Opinion in Rheumatology, 2003Co-Authors: Charlene J. WilliamsAbstract:The crystal deposition arthropathies comprise a host of disorders that may occur idiopathically or as secondary manifestations of associated diseases. Rarely, crystal deposition presents as a familial disorder. Most affected family members display radiographically detectable crystals of calcium pyrophosphate dihydrate in their joint spaces. In genetic studies of familial calcium pyrophosphate dihydrate deposition disease, a region on the short arm of chromosome 5 was found to be genetically linked to the phenotype displayed by several of these families. Among the positional candidates at this locus was ANKH, the human homolog of a gene that is responsible for the phenotype of progressive ankylosis (ank) in the mouse. ANKH codes for a transmembrane protein that appears to regulate the transport of inorganic pyrophosphate. It was analyzed as a potential positional candidate gene for calcium pyrophosphate dihydrate deposition disease, and in several unrelated families, sequence variants were identified that segregated with the calcium pyrophosphate dihydrate deposition disease phenotype among affected members. A discussion of ANKH as the familial calcium pyrophosphate dihydrate deposition disease gene is presented.
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Mutations in the amino terminus of ANKH in two US families with calcium pyrophosphate dihydrate crystal deposition disease
Arthritis and Rheumatism, 2003Co-Authors: Charlene J. Williams, Adrian Pendleton, Gina Bonavita, Shelly Peariso, Daniel J. Mccarty, Anne E Hughes, Antonio J Reginato, Michael Doherty, Lawrence M. RyanAbstract:OBJECTIVE: To analyze ANKH in families with calcium pyrophosphate dihydrate crystal deposition disease (CPPD) for disease-causing mutations. METHODS: Two US families (one of British ancestry and the other of German/Swiss ancestry) with autosomal-dominant CPPD, whose disease phenotypes were found to be linked to chromosome 5p15.1 (locus symbol CCAL2), were screened by direct sequencing for mutations in ANKH, a gene in the CCAL2 candidate interval that has been shown to harbor mutations in other families with CPPD. Observed sequence variants were confirmed by antisense sequencing, and expression of the mutant allele was verified by reverse transcriptase-polymerase chain reaction amplification of messenger RNA followed by direct sequencing. RESULTS: The two US families displayed the same mutation at position 5 of the ANKH gene product (P5T). All affected members were heterozygous for the P-to-T variant, and the mutation was not seen in 204 control alleles. The two families displayed distinct disease haplotypes, suggesting that they were unrelated to each other. CONCLUSION: These observations represent the fourth and fifth families with heritable CPPD whose disease phenotypes are linked to the CCAL2 locus and who have missense mutations in the amino terminus of ANKH. This same position (P5) was the site of a missense mutation in an Argentine family of northern Italian ancestry; however, the sequence variant in that family generated a P5L mutation. The distinct disease haplotypes among the 3 families with P5 mutations suggest that the mutations arose independently and that the evolutionarily conserved P5 position of ANKH may represent a hot spot for mutation in families with autosomal-dominant CPPD.
Hing Wo Tsui - One of the best experts on this subject based on the ideXlab platform.
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the cppdd associated ANKH m48t mutation interrupts the interaction of ANKH with the sodium phosphate cotransporter pit 1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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The CPPDD-Associated ANKH M48T Mutation Interrupts the Interaction of ANKH with the Sodium/Phosphate Cotransporter PiT-1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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the ANKH δe490mutation in calcium pyrophosphate dihydrate crystal deposition disease cppdd affects tissue non specific alkaline phosphatase tnap activities
The Open Rheumatology Journal, 2008Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Frank Beier, Kenneth P.h. Pritzker, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (ΔE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (ΔE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH ΔE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
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The ANKH DeltaE490Mutation in Calcium Pyrophosphate Dihydrate Crystal Deposition Disease (CPPDD) Affects Tissue Non-specific Alkaline Phosphatase (TNAP) Activities.
The open rheumatology journal, 2008Co-Authors: Frank Beier, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, John Wang, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (DeltaE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (DeltaE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH DeltaE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
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microcytosis in ank ank mice and the role of ANKH in promoting erythroid differentiation
Experimental Cell Research, 2007Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, Chen Wang, Facundo Las Heras, Emily Y Cheng, Norman N Iscove, Basil Chiu, Florence W L TsuiAbstract:Abstract Progressive ankylosis (Ank and the human homolog, ANKH) is a transmembrane protein which regulates transport of inorganic pyrophosphate (PPi). ank/ank mice with a mutated ank gene, have calcification and bone ankylosis of the affected joints. In the course of studying these mutant mice, we found that they have microcytosis. These mutant mice have lower mean red blood cell volume (MCV) and lower hemoglobin content in red cells (mean corpuscular hemoglobin, MCH) than normal mice. Using quantitative real-time PCR analysis, we showed that Ank was expressed in the E/Meg bipotent precursor, BFU-E, CFU-E, but there was no Ank expression in the hemoglobinizing erythroblasts. Stable ANKH transfectants in K562 cells highly expressed two immature erythroid cell markers, E-cadherin and endoglin. Enhanced Erythropoietin (Epo) expression and downregulation of SHP-1 were detected in these transfectants. Consequently, the autocrine Epo–EpoR signaling pathway was activated, as evidenced by higher p-Tyr JAK2, p-Tyr EpoR and p-Tyr STAT5B in the ANKH transfectants. Our results revealed a novel function of ANKH in the promotion of early erythroid differentiation in K562 cells. We also showed that ank/ank mice have lower serum levels of Epo than the normal littermates, and this is the likely cause of microcytosis in these mutant mice.
Frank Beier - One of the best experts on this subject based on the ideXlab platform.
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the cppdd associated ANKH m48t mutation interrupts the interaction of ANKH with the sodium phosphate cotransporter pit 1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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The CPPDD-Associated ANKH M48T Mutation Interrupts the Interaction of ANKH with the Sodium/Phosphate Cotransporter PiT-1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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the ANKH δe490mutation in calcium pyrophosphate dihydrate crystal deposition disease cppdd affects tissue non specific alkaline phosphatase tnap activities
The Open Rheumatology Journal, 2008Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Frank Beier, Kenneth P.h. Pritzker, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (ΔE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (ΔE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH ΔE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
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The ANKH DeltaE490Mutation in Calcium Pyrophosphate Dihydrate Crystal Deposition Disease (CPPDD) Affects Tissue Non-specific Alkaline Phosphatase (TNAP) Activities.
The open rheumatology journal, 2008Co-Authors: Frank Beier, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, John Wang, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (DeltaE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (DeltaE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH DeltaE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
John L Wang - One of the best experts on this subject based on the ideXlab platform.
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the cppdd associated ANKH m48t mutation interrupts the interaction of ANKH with the sodium phosphate cotransporter pit 1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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The CPPDD-Associated ANKH M48T Mutation Interrupts the Interaction of ANKH with the Sodium/Phosphate Cotransporter PiT-1
The Journal of Rheumatology, 2009Co-Authors: John L Wang, Hing Wo Tsui, Frank Beier, Florence W L TsuiAbstract:Objective. Numerous dominant human homolog of progressive ankylosis ( ANKH ) mutations have been identified in familial calcium pyrophosphate dihydrate crystal deposition disease (CPPDD). Due to the dominant nature of these mutations, we investigated whether ANKH interacts with other proteins; and if so, whether any CPPDD-associated ANKH mutation might disrupt such protein interactions. Methods. Stable ATDC5 ANKH wt- and ANKH M48T- transfectants were generated. Lysates from these transfectants were used to identify candidate protein interaction with ANKH by coimmunoprecipitation followed by Western blot analysis. The effect of high phosphate on the expression of genes involved in modulating Pi (inorganic phosphate)/PPi (inorganic pyrophosphate) homeostasis in these transfectants was assessed. Results. We showed that ANKH protein associates with the sodium/phosphate cotransporter PiT-1, and that ANKH M48T mutant protein failed to interact with PiT-1. We also showed that upon high phosphate treatment, the normally coordinated upregulation of endogenous Ank and PiT1 transcript expression was disrupted in ANKH M48T transfectants. Conclusion Our results suggested that there is a coordinated interrelationship between 2 key participants of Pi and PPi metabolism, ANKH and PiT-1.
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the ANKH δe490mutation in calcium pyrophosphate dihydrate crystal deposition disease cppdd affects tissue non specific alkaline phosphatase tnap activities
The Open Rheumatology Journal, 2008Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Frank Beier, Kenneth P.h. Pritzker, Florence W L TsuiAbstract:ANKH (human homolog of progressive ankylosis) regulates inorganic pyrophosphate (PPi) transport. Dominant ANKH mutations were detected in at least five multiplex families with calcium pyrophosphate dihydrate crystal deposition disease (CPPPD). The objective of this study is to assess the functional consequences of one CPPDD-associated ANKH mutation (ΔE490) in chondrogenic ATDC5 cells. Stable ATDC5 transfectants bearing myc-tagged constructs of wild-type ANKH, mutant ANKH (ΔE490) and neo controls were generated. Upon ITS (insulin, transferrin and selenium) induction, expression of chondrocyte markers including alkaline phosphatase activity in the various transfectants was assessed. The ANKH ΔE490- transfectants had low alkaline phosphatase activities throughout ITS treatment due to lower TNAP protein expression and the presence of intracellular low-molecular-weight inhibitors. Our results suggest that the interplay of ANKH and TNAP activities is tightly regulated.
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microcytosis in ank ank mice and the role of ANKH in promoting erythroid differentiation
Experimental Cell Research, 2007Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, Chen Wang, Facundo Las Heras, Emily Y Cheng, Norman N Iscove, Basil Chiu, Florence W L TsuiAbstract:Abstract Progressive ankylosis (Ank and the human homolog, ANKH) is a transmembrane protein which regulates transport of inorganic pyrophosphate (PPi). ank/ank mice with a mutated ank gene, have calcification and bone ankylosis of the affected joints. In the course of studying these mutant mice, we found that they have microcytosis. These mutant mice have lower mean red blood cell volume (MCV) and lower hemoglobin content in red cells (mean corpuscular hemoglobin, MCH) than normal mice. Using quantitative real-time PCR analysis, we showed that Ank was expressed in the E/Meg bipotent precursor, BFU-E, CFU-E, but there was no Ank expression in the hemoglobinizing erythroblasts. Stable ANKH transfectants in K562 cells highly expressed two immature erythroid cell markers, E-cadherin and endoglin. Enhanced Erythropoietin (Epo) expression and downregulation of SHP-1 were detected in these transfectants. Consequently, the autocrine Epo–EpoR signaling pathway was activated, as evidenced by higher p-Tyr JAK2, p-Tyr EpoR and p-Tyr STAT5B in the ANKH transfectants. Our results revealed a novel function of ANKH in the promotion of early erythroid differentiation in K562 cells. We also showed that ank/ank mice have lower serum levels of Epo than the normal littermates, and this is the likely cause of microcytosis in these mutant mice.
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Microcytosis in ank/ank mice and the role of ANKH in promoting erythroid differentiation.
Experimental Cell Research, 2007Co-Authors: John L Wang, Robert D. Inman, Hing Wo Tsui, Kenneth P.h. Pritzker, Chen Wang, Facundo Las Heras, Emily Y Cheng, Norman N Iscove, Basil Chiu, Florence W L TsuiAbstract:Abstract Progressive ankylosis (Ank and the human homolog, ANKH) is a transmembrane protein which regulates transport of inorganic pyrophosphate (PPi). ank/ank mice with a mutated ank gene, have calcification and bone ankylosis of the affected joints. In the course of studying these mutant mice, we found that they have microcytosis. These mutant mice have lower mean red blood cell volume (MCV) and lower hemoglobin content in red cells (mean corpuscular hemoglobin, MCH) than normal mice. Using quantitative real-time PCR analysis, we showed that Ank was expressed in the E/Meg bipotent precursor, BFU-E, CFU-E, but there was no Ank expression in the hemoglobinizing erythroblasts. Stable ANKH transfectants in K562 cells highly expressed two immature erythroid cell markers, E-cadherin and endoglin. Enhanced Erythropoietin (Epo) expression and downregulation of SHP-1 were detected in these transfectants. Consequently, the autocrine Epo–EpoR signaling pathway was activated, as evidenced by higher p-Tyr JAK2, p-Tyr EpoR and p-Tyr STAT5B in the ANKH transfectants. Our results revealed a novel function of ANKH in the promotion of early erythroid differentiation in K562 cells. We also showed that ank/ank mice have lower serum levels of Epo than the normal littermates, and this is the likely cause of microcytosis in these mutant mice.
