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Abstract
Recombinant DNA technology has led to accelerating introduction of novel therapeutics for the treatment of haemophilia. This technology has driven the development of recombinant clotting factors, extended half-life clotting factors, alternative biologics to promote haemostasis and enabled the launch of the gene therapy era for haemophilia. At the core of this technology is the ability to study the structure and function of the native molecules and to apply rational bioengineering to overcome limitations to the existing therapies. Through the study of haemophilia-causing mutations, site-directed mutagenesis, detailed structural models and a wide repertoire of animal models, new bioengineering strategies are helping overcome some of the remaining limitations and challenges of traditional clotting factor concentrates. Some of these bioengineering strategies are now being partnered with improvements in vectorology leading to the first wave of successful gene therapy approaches. This study will review past and present bioengineered molecules that are advancing care for haemophilia as well as novel approaches that promise to continue to improve care and outcomes for patients with haemophilia.
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Affiliation(s)
- S W Pipe
- University of Michigan, Ann Arbor, MI, USA
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2
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Carcao M, Shapiro A, Staber JM, Hwang N, Druzgal C, Lieuw K, Belletrutti M, Thornburg CD, Ahuja SP, Morales-Arias J, Dumont J, Miyasato G, Tsao E, Jain N, Pipe SW. Recombinant factor VIII Fc fusion protein for immune tolerance induction in patients with severe haemophilia A with inhibitors-A retrospective analysis. Haemophilia 2018; 24:245-252. [PMID: 29436077 DOI: 10.1111/hae.13413] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2018] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Immune tolerance induction (ITI) is the gold standard for eradication of factor VIII inhibitors in severe haemophilia A; however, it usually requires treatment for extended periods with associated high burden on patients and healthcare resources. AIM Review outcomes of ITI with recombinant factor VIII Fc fusion protein (rFVIIIFc) in patients with severe haemophilia A and high-titre inhibitors. METHODS Multicentre retrospective chart review of severe haemophilia A patients treated with rFVIIIFc for ITI. RESULTS Of 19 patients, 7 were first-time ITI and 12 were rescue ITI. Of 7 first-time patients, 6 had at least 1 high-risk feature for ITI failure. Four of 7 first-time patients were tolerized in a median of 7.8 months. The remaining 3 patients continue on rFVIIIFc ITI. Of 12 rescue patients, 7 initially achieved a negative Bethesda titre (≤0.6) in a median of 3.3 months, 1 had a decrease in Bethesda titre and continues on rFVIIIFc ITI and 4 have not demonstrated a decrease in Bethesda titre. Of these 4, 3 continue on rFVIIIFc ITI and 1 switched to bypass therapy alone. Two initially responsive patients transitioned to other factors due to recurrence. Overall, 16 of 19 patients remain on rFVIIIFc (prophylaxis or ITI). For those still undergoing ITI, longer follow-up is needed to determine final outcomes. No adverse events reported. CONCLUSIONS Recombinant factor VIII Fc fusion protein demonstrated rapid time to tolerization in high-risk first-time ITI patients. For rescue ITI, rFVIIIFc showed therapeutic benefit in some patients who previously failed ITI with other products. These findings highlight the need to further evaluate the use of rFVIIIFc for ITI.
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Affiliation(s)
- M Carcao
- Division of Haematology/Oncology, Department of Paediatrics, Child Health Evaluative Sciences, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - A Shapiro
- Indiana Hemophilia & Thrombosis Center, Indianapolis, IN, USA
| | - J M Staber
- University of Iowa Stead Family Children's Hospital, Iowa City, IA, USA
| | - N Hwang
- Center for Inherited Blood Disorders, Orange, CA, USA
| | - C Druzgal
- University of Virginia Health System, Charlottesville, VA, USA
| | - K Lieuw
- Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - M Belletrutti
- University of Alberta Stollery Children's Hospital, Edmonton, AB, Canada
| | - C D Thornburg
- Rady Children's Hospital San Diego, San Diego, CA, USA
| | - S P Ahuja
- University Hospitals Rainbow Babies and Children's Hospital, Cleveland, OH, USA
| | | | - J Dumont
- Bioverativ Therapeutics, Inc., Waltham, MA, USA
| | | | - E Tsao
- Bioverativ Therapeutics, Inc., Waltham, MA, USA
| | - N Jain
- Bioverativ Therapeutics, Inc., Waltham, MA, USA
| | - S W Pipe
- University of Michigan, Ann Arbor, MI, USA
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Weyand AC, Jesudas R, Pipe SW. Advantage of recombinant von Willebrand factor for peri-operative management in paediatric acquired von Willebrand syndrome. Haemophilia 2018; 24:e120-e121. [DOI: 10.1111/hae.13436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. C. Weyand
- Department of paediatrics and Communicable Diseases; University of Michigan; Ann Arbor MI USA
| | - R. Jesudas
- Bleeding and Clotting Disorders Institute; Peoria IL USA
| | - S. W. Pipe
- Department of paediatrics and Communicable Diseases; University of Michigan; Ann Arbor MI USA
- Department of Pathology; University of Michigan; Ann Arbor MI USA
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Peyvandi F, Makris M, Collins P, Lillicrap D, Pipe SW, Iorio A, Rosendaal FR. Minimal dataset for post-registration surveillance of new drugs in hemophilia: communication from the SSC of the ISTH. J Thromb Haemost 2017; 15:1878-1881. [PMID: 28767195 DOI: 10.1111/jth.13762] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Indexed: 11/27/2022]
Affiliation(s)
- F Peyvandi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Luigi Villa Foundation, Milan, Italy
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - M Makris
- Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, Sheffield, UK
| | - P Collins
- Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, UK
| | - D Lillicrap
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Canada
| | - S W Pipe
- Pediatrics and Pathology, University of Michigan, Ann Arbor, MI, USA
| | - A Iorio
- Department of Health Research Methods, Evidence, and Impact, and Department of Medicine, McMaster University, Hamilton, Canada
| | - F R Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
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Pierce GF, Ragni MV, van den Berg HM, Weill A, O'Mahony B, Skinner MW, Pipe SW. Establishing the appropriate primary endpoint in haemophilia gene therapy pivotal studies. Haemophilia 2017; 23:643-644. [DOI: 10.1111/hae.13313] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2017] [Indexed: 02/05/2023]
Affiliation(s)
- G. F. Pierce
- National Hemophilia Foundation Medical and Scientific Advisory Council; New York NY USA
- World Federation of Hemophilia; Montreal Quebec Canada
| | - M. V. Ragni
- National Hemophilia Foundation Medical and Scientific Advisory Council; New York NY USA
| | | | - A. Weill
- World Federation of Hemophilia; Montreal Quebec Canada
| | - B. O'Mahony
- European Haemophilia Consortium; Brussels Belgium
| | - M. W. Skinner
- National Hemophilia Foundation Medical and Scientific Advisory Council; New York NY USA
| | - S. W. Pipe
- National Hemophilia Foundation Medical and Scientific Advisory Council; New York NY USA
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6
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Pipe SW, Kessler CM. Evidence-based guidelines support integrated disease management as the optimal model of haemophilia care. Haemophilia 2017; 22 Suppl 3:3-5. [PMID: 27348395 DOI: 10.1111/hae.12997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S W Pipe
- Departments of Pediatrics and Pathology, University of Michigan, Ann Arbor, MI, USA
| | - C M Kessler
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
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Valentino LA, Pipe SW, Collins PW, Blanchette VS, Berntorp E, Fischer K, Ewenstein BM, Oh M, Spotts G. Association of peak factor
VIII
levels and area under the curve with bleeding in patients with haemophilia A on every third day pharmacokinetic‐guided prophylaxis. Haemophilia 2016; 22:514-20. [DOI: 10.1111/hae.12905] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2015] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - E. Berntorp
- Lund University Skane University Hospital Malmö Sweden
| | - K. Fischer
- Van Creveldkliniek University Medical Center Utrecht Utrecht the Netherlands
| | | | - M. Oh
- Baxter Healthcare Corporation Westlake Village CA USA
| | - G. Spotts
- Baxter Healthcare Corporation Westlake Village CA USA
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Chitlur M, Pipe SW, Reding MT, Kessler CM. Overcoming the diagnostic and monitoring challenges for very rare bleeding disorders in the US: the potential benefits of a centralized laboratory. Haemophilia 2016; 22:15-9. [PMID: 26809835 DOI: 10.1111/hae.12775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2015] [Indexed: 11/28/2022]
Affiliation(s)
- M Chitlur
- Wayne State University, Children's Hospital of Michigan, Detroit, USA
| | - S W Pipe
- University of Michigan, Ann Arbor, MI, USA
| | - M T Reding
- University of Minnesota, Minneapolis, MN, USA
| | - C M Kessler
- Georgetown University Medical Center, Washington, DC, USA
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Metzner HJ, Pipe SW, Weimer T, Schulte S. Extending the pharmacokinetic half-life of coagulation factors by fusion to recombinant albumin. Thromb Haemost 2013; 110:931-9. [PMID: 24178510 DOI: 10.1160/th13-03-0213] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/17/2013] [Indexed: 11/05/2022]
Abstract
The prophylactic treatment of haemophilia B and the management of haemophilia A or B with inhibitors demand frequent administrations of coagulation factors due to the suboptimal half-lives of the products commercially available and currently in use, e.g. recombinant factor IX (rFIX) and recombinant factor VIIa (rFVIIa), respectively. The extension of the half-lives of rFIX and rFVIIa could allow for longer intervals between infusions and could thereby improve adherence and clinical outcomes and may improve quality of life. Albumin fusion is one of a number of different techniques currently being examined to prolong the half-life of rFIX and rFVIIa. Results from a phase I clinical trial demonstrated that the recombinant fusion protein linking FIX to albumin (rIX-FP) has a five-times longer half-life than rFIX, and preclinical studies with the recombinant fusion protein linking FVIIa to albumin (rVIIa-FP) suggest that rVIIa-FP possesses a significantly extended half-life versus rFVIIa. In this review, we describe albumin fusion technology and examine the recent progress in the development of rIX-FP and rVIIa-FP.
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Affiliation(s)
- H J Metzner
- Hubert J. Metzner, CSL Behring GmbH, Emil-von-Behring-Str. 76, 35041 Marburg, Germany, Tel.: +49 6421 394417, Fax: +49 6421 394663, E-mail:
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10
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Goldenberg NA, Kruse-Jarres R, Frick N, Pipe SW, Leissinger CA, Kessler CM. Outcomes of mentored, grant-funded fellowship training in haemostasis /thrombosis: findings from a nested case-control survey study. Haemophilia 2011; 18:326-31. [PMID: 21899663 DOI: 10.1111/j.1365-2516.2011.02626.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Successful strategies by which to effectively recruit and retain academic subspecialists in benign haematology have not been established. To evaluate the effectiveness of a grant-funded, mentored fellowship with respect to retention and early career goals in haemostasis/thrombosis, we sought to compare outcomes for graduates of a grant-funded, mentored fellowship training programme in haemostasis/thrombosis [the National Hemophilia Foundation (NHF)-Baxter Clinical Fellowship Award] during conventional haematology/oncology fellowship training (cases), vs. their training peers who were graduates of conventional haematology/oncology fellowship training alone (controls), via a nested case-control survey study. Survey response rate was 85% (11/13) for cases and 90% (9/10) for controls. All respondents had pursued careers in academic haematology/oncology. Median (range) percent time spent in benign haematology postfellowship was 98% (70-100%) for cases vs. 0% (0-20%) for controls. Time spent in research was significantly greater among cases than controls (median 80% [range: 42-90%] vs. 55% [10-80%], respectively; P = 0.01). By years 3-4 postfellowship, median annual number of peer-reviewed publications was higher for cases than controls (3.5 vs. 1.0; P = 0.01). Cases were also more successful in grant funding (including K-awards). These data suggest that a grant-funded, mentored fellowship training programme in haemostasis/thrombosis may be superior to conventional haematology/oncology fellowship training alone with respect to outcomes of retention in clinical care/research, early-career grant funding and publication productivity.
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Affiliation(s)
- N A Goldenberg
- Section of Hematology/Oncology/Bone Marrow Transplantation and the Mountain States Regional Hemophilia and Thrombosis Center, Department of Pediatrics, University of Colorado, Aurora, CO 80045-0507, USA.
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11
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Abstract
Unravelling the structure, function and molecular interactions of factor VIII (FVIII) throughout its life cycle from biosynthesis to clearance has advanced our understanding of the molecular mechanisms of haemophilia and the development of effective treatment strategies including recombinant replacement therapy. These insights are now influencing bioengineering strategies toward novel therapeutics. Whereas available molecular models and crystal structures have helped elucidate the structure and function of the A and C domains of FVIII, these models have not included detailed structural information of the B domain. Therefore, insights into the role of the FVIII B domain have come primarily from expression studies in heterologous systems, biochemical studies on bioengineered FVIII variants and clinical studies with B domain-deleted FVIII. This manuscript reviews the available data on the potential functional roles of the FVIII B domain. A detailed literature search was performed, and the data extracted were qualitatively summarized. Intriguing emerging evidence suggests that the FVIII B domain is involved in intracellular interactions that regulate quality control and secretion, as well as potential regulatory roles within plasma during activation, platelet binding, inactivation and clearance.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA.
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12
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Valentino LA, Recht M, Dipaola J, Shapiro AD, Pipe SW, Ewing N, Urgo J, Bullock T, Simmons M, Deguzman C. Experience with a third generation recombinant factor VIII concentrate (Advate) for immune tolerance induction in patients with haemophilia A. Haemophilia 2009; 15:718-26. [PMID: 19298383 DOI: 10.1111/j.1365-2516.2008.01960.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The development of an inhibitor represents one of the most challenging complications in patients with haemophilia A. Optimal management is immune tolerance induction (ITI), typically through the administration of high doses of factor VIII (FVIII) concentrate. Among 12 patients who underwent ITI using Advate, a third-generation recombinant FVIII product that is free of animal and human protein additives, tolerance was achieved in nine (75%), including seven of 10 patients (70%) with high-titre inhibitors. ITI is ongoing in two patients and not yet successful; immune tolerance failed in the third patient. The median time to success was 4.0 months for group as a whole and for patients with high-titre inhibitors. Treatment was well tolerated, and no adverse events were observed. Advate was found to be equivalent to other FVIII products with regard to both ITI success rates and the incidence of adverse effects when used in these immune tolerance regimens.
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Affiliation(s)
- L A Valentino
- Department of Pediatrics, Rush University Medical Center, Chicago, IL 60612-3833, USA.
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13
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Cuker A, Ptashkin B, Konkle BA, Pipe SW, Whinna HC, Zheng XL, Cines DB, Pollak ES. Interlaboratory agreement in the monitoring of unfractionated heparin using the anti-factor Xa-correlated activated partial thromboplastin time. J Thromb Haemost 2009; 7:80-6. [PMID: 19017257 DOI: 10.1111/j.1538-7836.2008.03224.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND In an effort to improve interlaboratory agreement in the monitoring of unfractionated heparin (UFH), the College of American Pathologists (CAP) recommends that the therapeutic range of the activated partial thromboplastin time (APTT) be defined in each laboratory through correlation with a direct measure of heparin activity such as the factor Xa inhibition assay. Whether and to what extent this approach enhances the interlaboratory agreement of UFH monitoring has not been reported. OBJECTIVES We conducted a cross-validation study among four CAP-accredited coagulation laboratories to compare the interlaboratory agreement of the anti-FXa-correlated APTT with that of the traditional 1.5-2.5 times the midpoint of normal (1.5-2.5:control) method for defining the therapeutic APTT range. PATIENTS AND METHODS APTT and FXa inhibition assays were performed in each laboratory on plasma samples from 44 inpatients receiving UFH. RESULTS Using the anti-FXa-correlation method, there was agreement among all four laboratories as to whether a sample was subtherapeutic, therapeutic or supratherapeutic in seven (16%) patient samples. In contrast, consensus was achieved in 23 (52%) samples when the 1.5-2.5:control method was employed. CONCLUSIONS The anti-FXa-correlation method does not appear to enhance interlaboratory agreement in UFH monitoring as compared with the traditional 1.5-2.5:control method. Adoption of the anti-FXa-correlation method produces considerable disparity in UFH dosing decisions among different centers, although the clinical impact of this disparity is not known.
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Affiliation(s)
- A Cuker
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
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15
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Kasuda S, Kubo A, Sakurai Y, Irion S, Ohashi K, Tatsumi K, Nakajima Y, Saito Y, Hatake K, Pipe SW, Shima M, Yoshioka A. Establishment of embryonic stem cells secreting human factor VIII for cell-based treatment of hemophilia A. J Thromb Haemost 2008; 6:1352-9. [PMID: 18485084 DOI: 10.1111/j.1538-7836.2008.03022.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hemophilia A is an X-chromosome-linked recessive bleeding disorder resulting from an F8 gene abnormality. Although various gene therapies have been attempted with the aim of eliminating the need for factor VIII replacement therapy, obstacles to their clinical application remain. OBJECTIVES We evaluated whether embryonic stem (ES) cells with a tetracycline-inducible system could secrete human FVIII. METHODS AND RESULTS We found that embryoid bodies (EBs) developed under conditions promoting liver differentiation efficiently secreted human FVIII after doxycycline induction. Moreover, use of a B-domain variant F8 cDNA (226aa/N6) dramatically enhanced FVIII secretion. Sorting based on green fluorescent protein (GFP)-brachyury (Bry) and c-kit revealed that GFP-Bry(+)/c-kit(+) cells during EB differentiation with serum contain an endoderm progenitor population. When GFP-Bry(+)/c-kit(+) cells were cultured under the liver cell-promoting conditions, these cells secreted FVIII more efficiently than other populations tested. CONCLUSION Our findings suggest the potential for future development of an effective ES cell-based approach to treating hemophilia A.
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Affiliation(s)
- S Kasuda
- Department of Paediatrics, Nara Medical University, Kashihara, Nara, Japan
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Shi J, Pipe SW, Rasmussen JT, Heegaard CW, Gilbert GE. Lactadherin blocks thrombosis and hemostasis in vivo: correlation with platelet phosphatidylserine exposure. J Thromb Haemost 2008; 6:1167-74. [PMID: 18485093 DOI: 10.1111/j.1538-7836.2008.03010.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Platelet membrane phosphatidylserine (PS) is considered to be essential for hemostasis and thrombosis, but the in vivo topography of platelet PS has not been characterized. We hypothesized that platelet PS exposure would be identified on adherent platelets at the site of vascular injury and that blockade of PS would impede hemostasis and thrombosis. OBJECTIVE To localize and estimate the extent of platelet PS exposure and evaluate the impact of PS blockade in vivo. METHODS Lactadherin, a PS-binding milk protein, was utilized together with annexin V to detect both partial and complete membrane PS exposure on platelets in a mouse model of thrombosis and to evaluate the functional need for PS. Preliminary experiments were performed with synthetic membranes and with purified platelets. RESULTS The number of lactadherin-binding sites on synthetic membranes was proportional to PS content, whereas annexin V required a threshold of 2.5-8% PS. Approximately 95% of thrombin-stimulated platelets exposed PS, but the quantity was below the threshold for annexin V binding at physiologic Ca(2+) concentrations. In mice, most adherent and aggregated platelets on the walls of ferric chloride-treated mesenteric veins exposed low levels of PS, rather than having complete exposure. In mice, blockade of PS with lactadherin inhibited platelet prothrombinase and factor Xase activity, and prolonged tail bleeding time and the time to carotid artery thrombosis. CONCLUSIONS In vivo PS exposure contributes to both hemostasis and thrombosis. In this model of vascular injury, most platelets exhibit partial rather than complete PS exposure.
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Affiliation(s)
- J Shi
- Department of Medicine, VA Boston Healthcare System, Brigham, Women's Hospital and Harvard Medical School, Boston, MA 02132, USA
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
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18
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Abstract
Although immune tolerance induction (ITI) has been used for 30 years to eliminate inhibitors and restore normal factor pharmacokinetics in patients with hemophilia, there is a paucity of scientific evidence to guide therapeutic decision-making. In an effort to provide direction for physicians and hemophilia treatment center staff members, an international panel of hemophilia opinion leaders met to develop consensus recommendations for ITI in patients with severe and mild hemophilia A and hemophilia B. These recommendations draw on the available published literature and the collective clinical experience of the group and are rated based on the level of supporting evidence.
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Affiliation(s)
- D M DiMichele
- Department of Pediatrics, Weill Medical College of Cornell University, New York, NY 10021, USA.
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19
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Abstract
The World Federation of Hemophilia estimates that of the 400,000 individuals worldwide with hemophilia, 300,000 receive either no, or very sporadic, treatment. Thus, considerable innovation will be required to provide cost-effective therapies/cures for all affected individuals. The high cost of prophylactic regimens hampers their widespread use, which further justifies the search for novel cost-effective therapies and ultimately a cure. Five gene transfer phase I clinical trials have been conducted using either direct in vivo gene delivery with viral vectors or ex vivo plasmid transfections and reimplantation of gene-engineered cells. Although there was evidence of gene transfer and therapeutic effects in some of these trials, stable expression of therapeutic factor VIII or FIX levels has not yet been obtained. Further improvements of the vectors and a better understanding of the immune consequences of gene transfer is warranted, as new trials are being initiated. Bioengineered clotting factors with increased stability and/or activity are being validated further in preclinical studies. Novel clotting factor formulations based on PEGylated liposomes with prolonged activities are being tested in the clinic, and are yielding encouraging results.
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Affiliation(s)
- G F Pierce
- Bayer HealthCare LLC, 800 Dwight Way, Berkeley, CA 94710, USA.
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20
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Abstract
The reduced mortality, improved joint outcomes and enhanced quality of life, which have been witnessed in the developed world for patients with haemophilia, have been an outstanding achievement. Advancements in biotechnology contributed significantly through the development of improved pathogen screening, viral inactivation techniques and the development of recombinant clotting factors. These were partnered with enhanced delivery of care through comprehensive haemophilia centres, adoption of home therapy and most recently effective prophylaxis. This came at great costs to governments, medical insurers and patients' families. In addition, barriers persist limiting the adoption and adherence of effective prophylactic therapy. Biotechnology has been successful at overcoming similar barriers in other disease states. Long-acting biological therapeutics are an incremental advance towards overcoming some of these barriers. Strategies that have been successful for other therapeutic proteins are now being applied to factor VIII (FVIII) and include modifications such as the addition of polyethylene glycol (PEG) polymers and polysialic acids and alternative formulation with PEG-modified liposomes. In addition, insight into FVIII structure and function has allowed targeted modifications of the protein to increase the duration of its cofactor activity and reduce its clearance in vivo. The potential advantages and disadvantages of these approaches will be discussed.
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Affiliation(s)
- E L Saenko
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
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22
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Abstract
Over the past 20 years, transmissions of human immunodeficiency virus (HIV), hepatitis B virus or hepatitis C virus have been virtually eliminated from plasma-derived or recombinant therapy in the USA, a record that can be largely attributed to the use of effective screening and inactivation technologies for known pathogens. The next significant threat will likely come from the emergence of a new, blood-borne infectious disease, perhaps one transmitted by a non-lipid-enveloped virus or prion, for which current inactivation methods are ineffective. Following the HIV crisis of the 1980s, government, patient advocacy groups, medical and scientific communities and the manufacturers of clotting therapies can learn from the past and approach potential threats from emerging pathogens in a proactive and productive manner. For clinicians, this includes actively engaging patients in a dialogue about all the factors that may influence their choice of clotting factor therapies, including emerging pathogens, patient convenience, consistency and reliability of supply, relative cost/benefit ratios, reimbursement issues (where applicable), patient preference and brand loyalty. It is our obligation as healthcare providers to understand potential risks and help make proactive decisions with our patients, decisions that often must be made in an environment of scientific uncertainty. Threats from infectious agents that were once deemed theoretical can, and often do, ultimately become real, with serious implications for morbidity and mortality.
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Affiliation(s)
- S W Pipe
- Pediatric Hemophilia and Coagulation Disorders Program, University of Michigan, Women's Hospital, Ann Arbor, 48109, USA.
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23
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Abstract
The past 10 years of clinical experience have demonstrated the safety and efficacy of recombinant clotting factors. With the adoption of prophylactic strategies, there has been considerable progress in avoiding the complications of hemophilia. Now, insights from our understanding of clotting factor structure and function, mechanisms of hemophilia and inhibitors, gene therapy advances and a worldwide demand for clotting factor concentrates leave us on the brink of embracing targeted bioengineering strategies to further improve hemophilia therapeutics. The ability to bioengineer recombinant clotting factors with improved function holds promise to overcome some of the limitations in current treatment, the high costs of therapy and increase availability to a broader world hemophilia population. Most research has been directed at overcoming the inherent limitations of rFVIII expression and the inhibitor response. This includes techniques to improve rFVIII biosynthesis and secretion, functional activity, half-life and antigenicity/immunogenicity. Some of these proteins have already reached commercialization and have been utilized in gene therapy strategies, while others are being evaluated in pre-clinical studies. These novel proteins partnered with advances in gene transfer vector design and delivery may ultimately achieve persistent expression of FVIII leading to an effective long-term treatment strategy for hemophilia A. In addition, these novel FVIII proteins could be partnered with new advances in alternative recombinant protein production in transgenic animals yielding an affordable, more abundant supply of rFVIII. Novel rFIX proteins are being considered for gene therapy strategies whereas novel rVIIa proteins are being evaluated to improve the potency and extend their plasma half-life. This review will summarize the status of current recombinant clotting factors and the development and challenges of recombinant clotting factors bioengineered for improved function.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48109, USA.
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Abstract
This review will focus on new technologies in development that promise to lead to further advances in haemophilia therapeutics. There has been continued interest in the bioengineering of recombinant factor VIII (rFVIII) and factor IX (rFIX) with improved function to overcome some of the limitations in current treatment, the high costs of therapy and to increase availability to a broader world haemophilia population. Bioengineered forms of rFVIII, rFIX or alternative haemostatic molecules may ultimately have an impact on improving the efficacy of therapeutic strategies for the haemophilias by improving biosynthesis and secretion, functional activity, half-life and immunogenicity. Preventing and suppressing inhibitors to factor (F) VIII remain a challenge for both clinicians and scientists. Recent experiments have shown that it is possible to obtain anti-idiotypic antibodies with a number of desirable properties: (i) strong binding avidity to FVIII inhibitors; (ii) neutralization of inhibitory activity both in vitro and in vivo; (iii) cross-reactivity with antibodies from unrelated patients, and (iv) no interference with FVIII function. An alternative, although complementary approach, makes use of peptides derived from filamentous-phage random libraries. Mimotopes of FVIII can be obtained, which bind to the paratope of inhibitory activity and neutralize their activity both in vitro and in vivo. In this paper, we review advanced genetic strategies for haemophilia therapy. Until recently the traditional concept for gene transfer of inherited and acquired haematological diseases has been focused on how best to obtain stable insertion of a cDNA into a target-cell genome, allowing expression of a therapeutic protein. However, as gene-transfer vector systems continue to improve, the requirement for regulated gene transcription and hence regulated protein expression will become more critical. Inappropriate protein expression levels or expression of transferred cDNAs in non-intended cell types or tissues may lead to target-cell toxicity or activation of unwanted host immune responses. Regulated protein expression requires that the transferred gene be transferred with its own regulatory cassette that allows for gene transcription and translation approaching that of the normal gene in its endogenous context. New molecular techniques, in particular the use of RNA molecules, now allow for transcription of corrective genes that mimic the normal state.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.
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Abstract
Combined deficiency of both coagulation factors (F)V and VIII is a rare autosomal recessive bleeding disorder caused by null expression of LMAN1 (previously termed ERGIC-53) in a majority of affected individuals. Previously, a requirement for a functional LMAN1 cycling pathway between the ER and Golgi was demonstrated for efficient secretion of FV and FVIII (Moussalli et al. J Biol Chem 1999; 274: 32569), however, the molecular nature of the interaction between LMAN1 and its cargo was not characterized. Using coimmunoprecipitation of LMAN1 and FVIII from transfected HeLa and COS-1 cells, we demonstrate an interaction between LMAN1 and FVIII in vivo. The interaction was mediated via high mannose-containing asparagine-linked oligosaccharides that are densely situated within the B domain of FVIII, as well as protein-protein interactions. These results are interpreted based on the recent determination of the crystal structure of the carbohydrate recognition domain of LMAN1.
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Affiliation(s)
- M A Cunningham
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-0650, USA
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Abstract
Hemophilias A and B are X chromosome-linked bleeding disorders, which are mainly treated by repeated infusions of factor (F)VIII or FIX, respectively. In the present review, we specify the limitations in expression of recombinant (r)FVIII and summarize the bioengineering strategies that are currently being explored for constructing novel rFVIII molecules characterized by high efficiency expression and improved functional properties. We present the strategy to prolong FVIII lifetime by disrupting FVIII interaction with its clearance receptors and demonstrate how construction of human-porcine FVIII hybrid molecules can reduce their reactivity towards inhibitory antibodies. While the progress in improving rFIX is impeded by low recovery rates, the authors are optimistic that the efforts of basic science may ultimately lead to higher efficiency of replacement therapy of both hemophilias A and B.
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Affiliation(s)
- E L Saenko
- Department of Biochemistry, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross, Rockville, MD 20855, USA.
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Abstract
Wilms' tumor with tumor extension into the vena cava is a not uncommon variant of tumor presentation. Typically, this extension is nonadherent to the endothelium and readily lends itself to removal either before or after chemotherapy. This case illustrates an unusual variant in which the tumor within the cava was tightly adherent to the venous wall and required the complete excision of the vena cava, left renal vein, and a portion of the iliac system.
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Affiliation(s)
- E J Renaud
- Section of Pediatric Surgery, The Department of Surgery, The University of Michigan Medical School and C.S. Mott Children's Hospital, Ann Arbor, MI, USA
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Pipe SW, Saenko EL, Eickhorst AN, Kemball-Cook G, Kaufman RJ. Hemophilia A mutations associated with 1-stage/2-stage activity discrepancy disrupt protein-protein interactions within the triplicated A domains of thrombin-activated factor VIIIa. Blood 2001; 97:685-91. [PMID: 11157485 DOI: 10.1182/blood.v97.3.685] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thrombin-activated factor VIII (FVIIIa) is a heterotrimer with the A2 subunit (amino acid residues 373-740) in a weak ionic interaction with the A1 and A3-C1-C2 subunits. Dissociation of the A2 subunit correlates with inactivation of FVIIIa. Patients with hemophilia A have been described whose plasmas display a discrepancy between their FVIII activities, where the 1-stage activity assay displays greater activity than the 2-stage activity assay. The molecular basis for one of these mutations, (ARG)531(HIS), is an increased rate of A2 subunit dissociation. Examination of a homology model of the A domains of FVIII predicted (ARG)531 to lie at the interface of the A1 and A2 subunits and stabilize their interaction. Indeed, patients with mutations either directly contacting (ARG)531 ((ALA)284(GLU), (ALA)284(PRO)) or closely adjacent to the A1-A2 interface in the tightly packed hydrophobic core ((SER)289(LEU)) have the same phenotype of 1-stage/2-stage discrepancy. The (ALA)284(GLU) and (SER)289(LEU) mutations in FVIII were produced by transfection of COS-1 monkey cells. Compared to FVIII wild-type both mutants had reduced specific activity by 1-stage clotting activity and at least a 2-fold lower activity by 2-stage analysis (COAMATIC), similar to the reported clinical data. Analysis of immunoaffinity purified (ALA)284(GLU) and (SER)289(LEU) proteins in an optical biosensor demonstrated that A2 dissociation was 3-fold faster for both FVIIIa mutants compared to FVIIIa wild-type. Therefore, these mutations within the A1 subunit of FVIIIa introduce a similar destabilization of the FVIIIa heterotrimer compared to the (ARG)531(HIS) mutation within the A2 subunit and support that these residues stabilize the A domain interface of FVIIIa.
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Affiliation(s)
- S W Pipe
- Departments of Pediatrics and Biological Chemistry, Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor, MI, USA
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Moussalli M, Pipe SW, Hauri HP, Nichols WC, Ginsburg D, Kaufman RJ. Mannose-dependent endoplasmic reticulum (ER)-Golgi intermediate compartment-53-mediated ER to Golgi trafficking of coagulation factors V and VIII. J Biol Chem 1999; 274:32539-42. [PMID: 10551804 DOI: 10.1074/jbc.274.46.32539] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The endoplasmic reticulum-Golgi intermediate compartment (ERGIC) is the site of segregation of secretory proteins for anterograde transport, via packaging into COPII-coated transport vesicles. ERGIC-53 is a homo-hexameric transmembrane lectin localized to the ERGIC that exhibits mannose-selective properties in vitro. Null mutations in ERGIC-53 were recently shown to be responsible for the autosomal recessive bleeding disorder, combined deficiency of coagulation factors V and VIII. We have studied the effect of defective ER to Golgi cycling by ERGIC-53 on the secretion of factors V and VIII. The secretion efficiency of factor V and factor VIII was studied in a tetracycline-inducible HeLa cell line overexpressing a wild-type ERGIC-53 or a cytosolic tail mutant of ERGIC-53 (KKAA) that is unable to exit the ER due to mutation of two COOH-terminal phenylalanine residues to alanines. The results show that efficient trafficking of factors V and VIII requires a functional ERGIC-53 cycling pathway and that this trafficking is dependent on post-translational modification of a specific cluster of asparagine (N)-linked oligosaccharides to a fully glucose-trimmed, mannose9 structure.
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Affiliation(s)
- M Moussalli
- Howard Hughes Medical Institute, University of Michigan School of Medicine, Ann Arbor, Michigan 48109, USA
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Kaufman RJ, Pipe SW. Regulation of factor VIII expression and activity by von Willebrand factor. Thromb Haemost 1999; 82:201-8. [PMID: 10605705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- R J Kaufman
- Howard Hughes Medical Institute, Ann Arbor, MI, USA.
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Pipe SW, Eickhorst AN, McKinley SH, Saenko EL, Kaufman RJ. Mild hemophilia A caused by increased rate of factor VIII A2 subunit dissociation: evidence for nonproteolytic inactivation of factor VIIIa in vivo. Blood 1999; 93:176-83. [PMID: 9864159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Approximately 5% of hemophilia A patients have normal amounts of a dysfunctional factor VIII (FVIII) protein and are termed cross-reacting material (CRM)-positive. FVIII is a heterodimer (domain structure A1-A2-B/A3-C1-C2) that requires thrombin cleavage to elicit procoagulant activity. Thrombin-activated FVIII is a heterotrimer with the A2 subunit (amino acid residues 373 to 740) in a weak ionic interaction with the A1 and A3-C1-C2 subunits. Dissociation of the A2 subunit correlates with inactivation of FVIII. Recently, a phenotype of CRM-positive hemophilia A patients has been characterized whose plasma displays a discrepancy between their FVIII activities, where the one-stage clotting assay displays greater activity than the two-stage clotting assay. One example is a missense mutation where ARG531 has been substituted by HIS531. An FVIII cDNA construct was prepared containing the ARG531(HIS) mutation and the protein was expressed in COS-1 monkey cells by transient DNA transfection. Metabolic labeling with [35S]-methionine demonstrated that ARG531(HIS) was synthesized at an equal rate compared with FVIII wild-type (WT) but had slightly reduced antigen in the conditioned medium, suggesting a modest secretion defect. A time course of structural cleavage of ARG531(HIS) demonstrated identical thrombin cleavage sites and rates of proteolysis as FVIII WT. Similar to the patient phenotypes, ARG531(HIS) had discrepant activity as measured by a one-stage activated partial thromboplastin time (aPTT) clotting assay (36% +/- 9.6% of FVIII WT) and a variation of the two-stage assay using a chromogenic substrate (COAMATIC; 19% +/- 6.9% of FVIII WT). Partially purified FVIII WT and ARG531(HIS) proteins were subjected to functional activation by incubation with thrombin. ARG531(HIS) demonstrated significantly reduced peak activity and was completely inactivated after 30 seconds, whereas FVIII WT retained activity until 2.5 minutes after activation. Because the ARG531(HIS) missense mutation predicts a charge change to the A2 subunit, we hypothesized that the ARG531(HIS) A2 subunit could be subject to more rapid dissociation from the heterotrimer. The rate of A2 dissociation, using an optical biosensor, was determined to be fourfold faster for ARG531(HIS) compared with FVIII WT. Because the two-stage assay involves a preincubation phase before assay measurement, an increased rate of A2 dissociation would result in an increased rate of inactivation and reduced specific activity.
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Affiliation(s)
- S W Pipe
- Departments of Pediatrics and Biological Chemistry, Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor, MI, 48109-0650, USA
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Abstract
Treatment of haemophilia A requires frequent infusion of plasma- or recombinant-derived factor VIII. This regimen is limited due to the high cost and inconvenient access to peripheral veins. In addition, patients frequently develop inhibitory antibodies that limit available therapeutic regimens. Two major advances in factor VIII research over the past 15 years were the ability to isolate homogeneous preparations of factor VIII and the isolation of the factor VIII gene that provided for a detailed biochemical and structural characterization of the factor VIII molecule. With an increased understanding of the requirements for factor VIII function, studies have attempted to produce improved factor VIII molecules for replacement therapy. These findings have produced forms of factor VIII that are more efficiently produced, that are less immunogenic, and that have higher specific activity. The future will see the engineering of novel factor VIII molecules with increased therapeutic efficiency while minimizing inhibitor antibody development. In addition, there are now structural models of factor VIII available that should in the future direct development of novel peptidomimetics that may eventually overcome the requirement for replacement therapy with factor VIII protein.
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Affiliation(s)
- R J Kaufman
- Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor 48109, USA.
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Pipe SW, Morris JA, Shah J, Kaufman RJ. Differential interaction of coagulation factor VIII and factor V with protein chaperones calnexin and calreticulin. J Biol Chem 1998; 273:8537-44. [PMID: 9525969 DOI: 10.1074/jbc.273.14.8537] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor VIII (FVIII) and factor V (FV) are homologous coagulation cofactors sharing a similar domain organization (A1-A2-B-A3-C1-C2) and are both extensively glycosylated within their B-domains. In mammalian cell expression systems, compared with FV, the FVIII primary translation product is inefficiently transported out of the endoplasmic reticulum. Here we show that FVIII is degraded within the cell by a lactacystin-inhibitable pathway, implicating the cytosolic 20 S proteasome machinery. Protein chaperones calnexin (CNX) and calreticulin (CRT) preferentially interact with glycoproteins containing monoglucosylated N-linked oligosaccharides and are proposed to traffic proteins through degradative and/or secretory pathways. Utilizing co-immunoprecipitation assays, intracellular FVIII was detected in association with CNX maximally within 30 min to 1 h following synthesis, whereas FV could not be detected in association with CNX. In contrast, both FVIII and FV displayed interaction with CRT during transit through the secretory pathway. B-domain deleted FVIII significantly reduced the CNX and CRT interaction, indicating the B-domain may represent a primary CNX and CRT interaction site. In the presence of inhibitors of glucose trimming, the interactions of FVIII with CNX, and of FVIII and FV with CRT, were significantly reduced whereas the secretion of FVIII, and not FV, was inhibited. In addition, transfection in a glucosidase I-deficient Chinese hamster ovary cell line (Lec23) demonstrated that both degradation and secretion of FVIII were inhibited, with little effect on the secretion of FV. These results support that CNX and CRT binding, mediated at least in part by the B-domain of FVIII, is required for efficient FVIII degradation and secretion. In contrast, FV does not require CNX interaction for efficient secretion. The results suggest a unique requirement for carbohydrate processing and molecular chaperone interactions that may limit the productive secretion of FVIII.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, The University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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35
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Kaufman RJ, Pipe SW, Tagliavacca L, Swaroop M, Moussalli M. Biosynthesis, assembly and secretion of coagulation factor VIII. Blood Coagul Fibrinolysis 1997; 8 Suppl 2:S3-14. [PMID: 9607108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Factor VIII is a large complex glycoprotein that is deficient in hemophilia A. It has a domain organization consisting of A1-A2-B-A3-C1-C2 where the B domain is a heavily glycosylated region that is dispensable for procoagulant activity. Factor VIII expression is 10-to 20-fold lower than the homologous coagulation factor V. Factor VIII expression is limited due to a low level of steady-state messenger RNA in the cytoplasm and inefficient transport of the primary translation product from the endoplasmic reticulum to the Golgi apparatus. Within the secretory pathway, factor VIII is processed to a heterodimer of the heavy chain (domains A1-A2-B) in a metal ion association with the light chain (domains A3-C1-C2). Upon secretion from the cell, von Willebrand factor binds the light chain of factor VIII and stabilizes the factor, preventing degradation. Protein folding within the mammalian secretory pathway is facilitated by molecular chaperones. Within the endoplasmic reticulum, factor VIII exhibits stable interaction with protein chaperones identified as the immunoglobulin-binding protein (BiP), calnexin and calreticulin. BiP is a peptide-dependent ATPase that interacts with exposed hydrophobic surfaces on unfolded proteins or unassembled protein subunits. A potential BiP binding site within factor VIII has been identified. Mutation of a single amino acid residue in the potential BiP binding site increased the secretion efficiency of factor VIII by threefold. Interestingly, the proposed BiP binding site is adjacent to a type-1 copper binding site within the A1 domain that is required for interaction between the factor VIII A1 domain and the A3 domain. We propose that Cu(I) binds the type-1 copper ion-binding site in the A1 domain and provides the essential requirement for a stable interaction between the heavy and light chains. Calnexin and calreticulin are transmembrane and lumenal proteins, respectively, localized to the endoplasmic reticulum, which associate transiently with many soluble and membrane glycoproteins during folding and subunit assembly. The calnexin and calreticulin interaction with factor VIII occurs primarily through amino-terminal linked oligosaccharides within the heavily glycosylated factor VIII B domain and this interaction appears to be required for factor VIII secretion. The findings suggest that factor VIII cycles through interactions with BiP, calnexin and calreticulin. Although the interaction with BiP does not appear to be required for factor VIII secretion, data suggest that the calnexin and/or calreticulin interaction is required for secretion. The observations suggest a unique requirement for carbohydrate processing and calnexin/calreticulin interaction that may limit the productive secretion of factor VIII and have implications for approaches towards somatic cell gene therapy for hemophilia A.
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Affiliation(s)
- R J Kaufman
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of Michigan School of Medicine, Ann Arbor 48109, USA
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Pipe SW, Kaufman RJ. Characterization of a genetically engineered inactivation-resistant coagulation factor VIIIa. Proc Natl Acad Sci U S A 1997; 94:11851-6. [PMID: 9342326 PMCID: PMC23634 DOI: 10.1073/pnas.94.22.11851] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/1997] [Accepted: 08/26/1997] [Indexed: 02/05/2023] Open
Abstract
Individuals with hemophilia A require frequent infusion of preparations of coagulation factor VIII. The activity of factor VIII (FVIII) as a cofactor for factor IXa in the coagulation cascade is limited by its instability after activation by thrombin. Activation of FVIII occurs through proteolytic cleavage and generates an unstable FVIII heterotrimer that is subject to rapid dissociation of its subunits. In addition, further proteolytic cleavage by thrombin, factor Xa, factor IXa, and activated protein C can lead to inactivation. We have engineered and characterized a FVIII protein, IR8, that has enhanced in vitro stability of FVIII activity due to resistance to subunit dissociation and proteolytic inactivation. FVIII was genetically engineered by deletion of residues 794-1689 so that the A2 domain is covalently attached to the light chain. Missense mutations at thrombin and activated protein C inactivation cleavage sites provided resistance to proteolysis, resulting in a single-chain protein that has maximal activity after a single cleavage after arginine-372. The specific activity of partially purified protein produced in transfected COS-1 monkey cells was 5-fold higher than wild-type (WT) FVIII. Whereas WT FVIII was inactivated by thrombin after 10 min in vitro, IR8 still retained 38% of peak activity after 4 hr. Whereas binding of IR8 to von Willebrand factor (vWF) was reduced 10-fold compared with WT FVIII, in the presence of an anti-light chain antibody, ESH8, binding of IR8 to vWF increased 5-fold. These results demonstrate that residues 1690-2332 of FVIII are sufficient to support high-affinity vWF binding. Whereas ESH8 inhibited WT factor VIII activity, IR8 retained its activity in the presence of ESH8. We propose that resistance to A2 subunit dissociation abrogates inhibition by the ESH8 antibody. The stable FVIIIa described here provides the opportunity to study the activated form of this critical coagulation factor and demonstrates that proteins can be improved by rationale design through genetic engineering technology.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
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Swaroop M, Moussalli M, Pipe SW, Kaufman RJ. Mutagenesis of a potential immunoglobulin-binding protein-binding site enhances secretion of coagulation factor VIII. J Biol Chem 1997; 272:24121-4. [PMID: 9305856 DOI: 10.1074/jbc.272.39.24121] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Coagulation factor VIII (FVIII) and factor V are homologous glycoproteins that have a domain structure of A1-A2-B-A3-C1-C2. FVIII is a heterodimer of the heavy chain (domains A1-A2-B) and the light chain (domains A3-C1-C2) in a metal ion-dependent association between the A1- and A3-domains. Previous studies identified a 110-amino acid region within the FVIII A1-domain that inhibits its secretion and contains multiple short peptide sequences that have potential to bind immunoglobulin-binding protein (BiP). FVIII secretion requires high levels of intracellular ATP, consistent with an ATP-dependent release from BiP. Site-directed mutagenesis was used to elucidate the importance of the potential BiP-binding sites in FVIII secretion. Mutation of Phe at position 309 to Ser or Ala enhanced the secretion of functional FVIII and reduced its ATP dependence. The F309S FVIII had a specific activity, thrombin activation profile, and heat inactivation properties similar to those of wild-type FVIII. However, F309S FVIII displayed increased sensitivity to EDTA-mediated inactivation that is known to occur through metal ion chelation-induced dissociation of the heavy and light chains of FVIII. The results support that Phe309 is important in high affinity heavy and light chain interaction, and this correlates with a high affinity BiP-binding site. Introduction of the F309S mutation into other secretion defective FVIII mutants rescued their secretion, demonstrating the ability of the this mutation to improve secretion of mutant FVIII proteins retained in the cell.
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Affiliation(s)
- M Swaroop
- Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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38
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Abstract
The half-life of coagulation factor VIII (FVIII) in plasma is prolonged by noncovalent interaction with von Willebrand factor (vWF). Antibody inhibition data indicate that epitopes within the carboxyl terminus of the FVIII light chain play a role in vWF binding. Analysis of hemophilia A patient DNA samples have identified missense mutations within this carboxyl terminus of the FVIII light chain at amino acid 2307 in which arginine is replaced with either glutamine or leucine. Patients with these mutations have reduced FVIII activity proportional to reduced cross-reacting material in their plasma. It was hypothesized that the reduced levels of FVIII in plasma due to these mutations may be related to a defect in vWF binding with resultant plasma instability. Wild-type and mutant FVIII cDNA expression vectors were prepared and expressed in COS-1 monkey cells by transient DNA transfection. FVIII mutants R2307Q and R2307L were synthesized at equal rates compared to FVIII wild-type but had greater than 10-fold reduced accumulation of antigen and activity levels in the conditioned medium. An additional mutation, Y2305F, also displayed a similar defect in protein accumulation, whereas Y2332F was secreted similarly to wild-type. The specific activity of immunoaffinity purified R2307Q was mildly reduced compared to FVIII wild-type, whereas vWF binding properties were retained. Inhibition of intracellular cysteine proteases resulted in intracellular accumulation of R2307Q protein, suggesting that the mechanism leading to hemophilia A is related to a block in secretion and subsequent degradation within the secretory pathway rather than extracellular instability.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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Abstract
We report a case of neonatal purpura fulminans associated with activated protein C resistance. Analysis of DNA demonstrated heterozygosity for the factor V R506Q mutation. The neonate, at 8 hours of age, had progressive purpuric skin lesions and later had evidence of microvascular, hemorrhagic thrombosis in the brain. The baby was treated with fresh frozen plasma infusions and had complete resolution of the skin lesions and no apparent long-term complications. We suggest that activated protein C resistance testing be included in the initial evaluation of neonatal purpura fulminans.
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Affiliation(s)
- S W Pipe
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, USA
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