Androgen effects on factor IX expression: <i>in‐vitro</i> and <i>in‐vivo</i> studies in mice

Brady, Jolene N.; Notley, Colleen; Cameron, Charles J.; Lillicrap, David

doi:10.1046/j.1365-2141.1998.00694.x

Cited by 8 publications

(10 citation statements)

References 31 publications

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“…Mapping of transcription factor binding and regulation of the FIX promoter has been modeled in mice that recapitulate the hemophilia B Leyden phenotype, demonstrating age-dependent and sex-specific post-pubertal increases in FIX expression. 158; 159; 160 Elements in the 5’ and 3’ untranslated regions of the FIX gene that direct natural gender-independent age-associated increases in FIX expression have also been elucidated in mice with engineered FIX gene sequences. 156 …”

Section: The Hemophilia B Mouse Modelmentioning

confidence: 99%

Animal Models of Hemophilia

Sabatino

Nichols

Merricks

et al. 2012

Progress in Molecular Biology and Translational Science

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The X-linked bleeding disorder hemophilia is caused by mutations in coagulation factor VIII (hemophilia A) or factor IX (hemophilia B). Unless prophylactic treatment is provided, patients with severe disease (less than 1% clotting activity) typically experience frequent spontaneous bleeds. Current treatment is largely based on intravenous infusion of recombinant or plasma-derived coagulation factor concentrate. More effective factor products are being developed. Moreover, gene therapies for sustained correction of hemophilia are showing much promise in pre-clinical studies and in clinical trials. These advances in molecular medicine heavily depend on availability of well-characterized small and large animal models of hemophilia, primarily hemophilia mice and dogs. Experiments in these animals represent important early and intermediate steps of translational research aimed at development of better and safer treatments for hemophilia, such a protein and gene therapies or immune tolerance protocols. While murine models are excellent for studies of large groups of animals using genetically defined strains, canine models are important for testing scale-up and for longer-term follow-up as well as for studies that require larger blood volumes.

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Section: The Hemophilia B Mouse Modelmentioning

confidence: 99%

Animal Models of Hemophilia

Sabatino

Nichols

Merricks

et al. 2012

Progress in Molecular Biology and Translational Science

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“…3 Sufferers of hemophilia B Leyden express low levels of F9 up until puberty, at which point F9 levels rise and clinical symptoms improve; this phenomenon is associated with increasing androgen receptor and growth-factor activity. [4][5][6][7][8] To date, more than 80 families affected by hemophilia B Leyden have been analyzed worldwide and 21 distinct point mutations have been detected in the F9 promoter ( Figure 1). 12,13 The mutations fall into three clusters: one at nucleotide À20 relative to the transcription start site (TSS, designated þ1), one at around nucleotide þ10, and one at nucleotides -5 and -6 (À5/À6 site).…”

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confidence: 99%

A CpG Mutational Hotspot in a ONECUT Binding Site Accounts for the Prevalent Variant of Hemophilia B Leyden

Funnell

Wilson

Ballester

et al. 2013

The American Journal of Human Genetics

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Hemophilia B, or the "royal disease," arises from mutations in coagulation factor IX (F9). Mutations within the F9 promoter are associated with a remarkable hemophilia B subtype, termed hemophilia B Leyden, in which symptoms ameliorate after puberty. Mutations at the -5/-6 site (nucleotides -5 and -6 relative to the transcription start site, designated +1) account for the majority of Leyden cases and have been postulated to disrupt the binding of a transcriptional activator, the identity of which has remained elusive for more than 20 years. Here, we show that ONECUT transcription factors (ONECUT1 and ONECUT2) bind to the -5/-6 site. The various hemophilia B Leyden mutations that have been reported in this site inhibit ONECUT binding to varying degrees, which correlate well with their associated clinical severities. In addition, expression of F9 is crucially dependent on ONECUT factors in vivo, and as such, mice deficient in ONECUT1, ONECUT2, or both exhibit depleted levels of F9. Taken together, our findings establish ONECUT transcription factors as the missing hemophilia B Leyden regulators that operate through the -5/-6 site.

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“…A large component of the work presented in this chapter are results derived from in vitro expression studies using the pPMTR vector or variations of the pPMTR vector. A criticism that may be levelled at this system is the relatively low changes in expression observed post treatment when compared to changes observed for other hormonally responsive promoter studies for example, the 17-fold change found in the investigations of the F9 gene due to the ARE disrupting point mutation (Brady et al, 1998). However, the PROS1 promoter is known to be a low activity promoter (personal correspondence with Prof. David Lane, Hammersmith Hospital, London), a phenomenon that may actually reflect translational rather than transcriptional output.…”

Section: Pr Er Gr Mrmentioning

confidence: 99%

“…The prothrombotic shift results from upregulation of several key components of the procoagulant and fibrinolytic systems in combination with a down-regulation of the anticoagulation system, in particular reduced PS levels and increased aPC resistance. Previous investigations into the molecular mechanisms influencing these changes have focused on promoter regions of genes of the procoagulant and fibrinolytic systems (Farsetti et al, 1995, Brady et al, 1998, Heit et al, 1999a, Farsetti et al, 2001, Smith et al, 2004. The work discussed in this Chapter represents the first attempt to study hormonal regulation of the PROS1 promoter that governs the production of PS.…”

Section: Introductionmentioning

confidence: 99%

“…A haemostatic example is the gene that encodes FIX (F9). Experimental work performed in the 1990s identified an androgen response element (ARE) in the promoter of the F9 gene following investigation of a form of Haemophilia B known as Haemophilia B Leyden (Morgan et al, 1997, Brady et al, 1998, Heit et al, 1999a. FIX levels of patients with the Leyden form of Haemophilia B are low prior to the onset of puberty, but increase to within, or close to, normal ranges by the end of puberty.…”

Section: Introductionmentioning

confidence: 99%

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Hormonal Regulation of the Anticoagulant Protein S.

Hughes

Staton

Watson

et al. 2005

Blood

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The anticoagulant Protein S (PS) is coded for by the PROS1 gene and serves as a co-factor to APC in the inactivation of FVa and FVIIIa. It is produced predominately by the liver. Low PS levels are associated with an increased thrombotic risk. Clinically it is well documented that circulating PS levels are reduced in response to heightened estrogen (E2) levels (oral contraceptive use, pregnancy, etc.). However, an explanation as to how this is occurring at the molecular level has not yet been elucidated. Two approaches have been utilized. Firstly, a liver carcinoma cell line, HepG2, was exposed to 5 and 10nM concentrations of testosterone (T) and E2 for 6, 12 and 24h at which point’s total RNA was extracted and quantitated using real-time PCR. Secondly, a reporter plasmid pQH5′[2]DsRed2 was constructed that has 948bp of the PROS1 promoter region (up to but not including the ATG start codon) fused to an enhanced green fluorescent protein (EGFP) reporter gene sequence. A second reporter gene, DsRed2, was incorporated into pQH5′[2]DsRed2, and is constitutively expressed by a cytomegalovirus (CMV) promoter. This provides a means of standardizing any change in expression of the EGFP reporter. pQH5′[2]DsRed2 was transiently transfected into a breast cell carcinoma line MCF7 [chosen for its high levels of oestrogen receptor alpha (ERα)] and subsequently exposed to 5 and 10nM concentrations of E2 and T for 24h. Expression levels were assessed using a COULTER EPICS flow cytometer. The HepG2 6, 12 and 24h PROS1 mRNA hormone response experiment showed an erratic response to E2. However there were consistently higher levels of PROS1 mRNA over time in response to T compared to the vehicle alone. Higher levels still were evident for the 10nM concentration. The transient transfection of pQH5′[2]DsRed2 into MCF7s followed by a 24h exposure of either T or E2 at 5 and 10nM concentrations, showed a significant change in response to both the 5 and 10nM concentrations of E2, but little response to either of the T concentrations These results suggest that E2 is exerting a direct effect on the promoter of PROS1, down regulating transcription, reflecting clinical observations. However, T may be affecting PROS1 mRNA stability via a yet undetermined mechanism. Therefore, hormonal regulation of PS may be occurring at several levels of the overall production process.

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Androgen effects on factor IX expression: in‐vitro and in‐vivo studies in mice

Cited by 8 publications

References 31 publications

Animal Models of Hemophilia

Animal Models of Hemophilia

A CpG Mutational Hotspot in a ONECUT Binding Site Accounts for the Prevalent Variant of Hemophilia B Leyden

Hormonal Regulation of the Anticoagulant Protein S.

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