THROMBOPOIETIN, MEGAKARYOCYTOPOIESIS AND PLATELET PRODUCTION NIH Guide, Volume 26, Number 39, December 5, 1997 PA NUMBER: PA-98-014 P.T. National Heart, Lung, and Blood Institute National Institute of Diabetes, Digestive and Kidney Diseases PURPOSE The objective of this initiative is to understand the actions of thrombopoietin (TPO) at the molecular level in megakaryocyte proliferation and development, in platelet production, and in the regulation of platelet levels in vivo. The ultimate goal is to be able to regulate platelet levels as needed in vivo in a safe and efficacious manner. HEALTHY PEOPLE 2000 The Public Health Service (PHS) is committed to achieving the health promotion and disease prevention objectives of "Healthy People 2000", a PHS-led national activity for setting priority areas. This PA, Thrombopoietin, Megakaryocytopoiesis and Platelet Production, is related to the priority areas of cancer, and heart diseases and stroke. Potential applicants may obtain a copy of "Healthy People 2000" (Full Report: Stock No. 017-001-00474-0 or Summary Report: Stock No. 017-001-00473-1) through the Superintendent of Documents, Government Printing Office, Washington, DC 20402-9325 (telephone 202-512-1800). ELIGIBILITY REQUIREMENTS Applications may be submitted by domestic and foreign for-profit and non-profit organizations, public and private, such as universities, colleges, hospitals, laboratories, units of state or local governments, and eligible agencies of the federal government. Awards in response to this PA will be made to foreign institutions only for research of very unusual merit, need, and promise, and in accordance with PHS policy governing such awards. Racial/ethnic minority individuals, women, and persons with disabilities are encouraged to apply. The Mentored Clinical Scientist Development Award (K08) provides support to develop outstanding clinician research scientists. The candidate should hold a clinical doctoral degree and should have initiated postgraduate clinical training. Candidates must be U.S. Citizens, non-citizen nationals, or lawfully admitted for permanent residence. Applications may be submitted by a public or private, non-federal organization on behalf of the applicant. The candidate must identify a mentor with extensive research experience and must devote 75 percent effort to research career development activities during the period of the award. Former principal investigators on PHS research grants are not eligible and a concurrent PHS award may not be held. The National Research Service Award Individual Postdoctoral Fellowships (F32) offers health scientist the opportunity to receive full time research training in areas that reflect the national need for biomedical and behavioral research. By the award start date, applicants must have received a Ph.D., M.D., D.D.S., D.V.M., or equivalent degree and have arranged to work with a particular sponsor affiliated with a private or public institution that has the staff and facilities needed for the proposed training. Applicants must be U.S. Citizens, non-citizen nationals, or lawfully admitted for permanent residence. These awards are not intended for study leading to the M.D., D.O., D.D.S., or equivalent professional degrees nor do these awards support residency training. The National Research Service Award Senior Postdoctoral Fellowships (F33) permit experienced scientists to make major changes in the direction of their research careers, or to broaden their scientific background by acquiring new research capabilities. The Award may be used in conjunction with a sabbatical leave. By the award start date, an applicant must have at least 7 years of relevant postdoctoral research or professional training, and must have a sponsor affiliated with a public or private institution with appropriate facilities for the proposed training. These awards are not intended for study leading to a professional degree nor do these awards support residency training. Fellows must be U.S. citizens, non-citizen nationals, or have been lawfully admitted to the United States for permanent residence. MECHANISM OF SUPPORT This PA will use the research project grant (R01), the Mentored Clinical Scientist Development Award (K08), and National Research Service Award Individual and Senior Postdoctoral Fellowships (F32 and F33). Applications for R01 grants may request up to five years of support. Responsibility for the planning, direction, and execution of the proposed research for all applicable mechanisms of support will be solely that of the applicant. RESEARCH OBJECTIVES Background Platelets play an essential role in hemostasis and thrombosis. They are produced from bone marrow megakaryocytes and arise from fragmentation of the cytoplasm. If the level of circulating platelets drops below a certain number (thrombocytopenia), the patient runs the risk of catastrophic hemorrhage. Patients with cancer who have received chemotherapy or bone marrow transplants usually have thrombocytopenia, and the slow recovery of platelet count in these patients has been a concern. The demand for platelet units for transfusion has been steadily increasing primarily because of the need to maintain a certain platelet level in such patients with cancer or those undergoing major cardiac surgery. More than three decades ago, it was reported that a humoral factor present in the plasma of patients with severe thrombocytopenia increased the platelet count when injected in animals and this regulator was named thrombopoietin or TPO. The isolation of this cytokine proved to be a difficult task because of its low concentration in plasma and the lack of reliable assays. Meanwhile, other hematopoietic regulators with some proliferative effect on megakaryocytes were discovered: interleukin-3 (IL-3), IL-6, IL-11, and leukemia inhibitory factor (LIF). However, their action in increasing the platelet number proved to be minimal, and each showed some undesirable, non-specific effects. Identification of the myeloproliferative leukemia virus (MPLV) had a profound influence on efforts to isolate TPO. The responsible viral oncogene was cloned in 1990, and, two years later, the corresponding cellular proto-oncogene, c-mpl, was identified. The amino acid sequence of the latter showed the typical features of a cytokine receptor; in fact, it contained two "cytokine receptor motifs." In 1994, several groups almost simultaneously reported the isolation and characterization of TPO using three distinct strategies. The Mpl ligand, TPO, was cloned, and recombinant TPO proved to be powerful in increasing the number of platelets in vivo; however, its safety, specificity, and mechanism of action remain to be defined. With this magnificent discovery, megakaryocytopoiesis became a science and new talents and tools were brought to bear on the process. It became equally important to identify those basic research areas which are important but are unlikely to be supported by the biotechnology industry. It is also vital to consider all effects of TPO that might be involved in its use in humans, particularly in those patients with malignancies of the blood system. It is unknown whether or not thrombopoietin will be effective in raising platelet levels in humans specifically and safely. Preclinical testing of full-length TPO or a truncated, pegylated derivative molecule, termed megakaryocyte growth and development factor (MGDF), produced impressive results in mice and monkeys. The most recent data show that either form of TPO administered before chemotherapy resulted in a dose-dependent increase in peripheral platelet count. The rise occurred within 4 to 6 days after TPO administration and continued for up to 11 days. These data suggest that TPO affects early stages of hematopoiesis and confirms previous reports that it increases the frequency of multiple types of hematopoietic progenitors in the marrow and in blood. The magnitude of the response was also impressive since a modest amount of TPO for only a single day raised peripheral platelet count by > 200%. No significant adverse effects were associated with the drugs although in vitro studies indicated that TPO may prime platelets to respond to subthreshold levels of agonists. It should be noted, however, that patients selected for these studies were carefully screened to exclude pre-existing cardiovascular diseases, making the safety of these agents in an unselected patient population still an unresolved question. Another open issue is the effectiveness of TPO administered after cytotoxic therapy since an optimal cellular substrate of adequate quantity and quality will be necessary for TPO to be effective. TPO is a unique cytokine in that it not only promotes the differentiation and polyploidization of megakaryocytes, but it also increases the proliferation of megakaryocyte precursors. In conjunction with other cytokines, it is also known to increase the proliferation of CD34+ cells and the development of other lineages. Thus, administration of TPO to patients with blood malignancies may have a long term effect on cellular proliferation and on the malignant phenotype. It then becomes essential to understand the basic molecular mechanism by which TPO exerts each of its effects. Indeed TPO has been reported to upregulate the expression of specific cyclins and other cell cycle genes, which may control the cell cycle of a variety of hematopoietic lineages. The results of such basic studies are essential for safe and efficacious use of TPO in humans. Considerable excitement has been generated over the possible use of cord blood stem cells for transplantation. Recent data indicate that human bone marrow CD34+ CD38+ cells, which contain megakaryocyte progenitors, may be cultured in vitro with TPO in a serum-free medium leading to the formation of proplatelets and coagulant microparticles. The action of TPO on cord blood stem cells needs to be defined. In addition to its use in patients with thrombocytopenia, TPO is likely to be considered for administration to normal donors of platelets. Over 7 million units of platelet concentrates are transfused annually in the United States. Approximately 35 to 50% of these are solicited from individual donors in whom the use of TPO could increase platelet yields by 200 to 400%. Both EPO or G-CSF have been used in normal donors as part of autologous blood or stem cell collections, or as part of allogeneic granulocyte donation programs. However, the effects of TPO on normal individuals are unknown and need to be investigated before such use. In spite of significant progress, the manner of production and regulation of TPO and the physiological sensing mechanisms remain unclear. Megakaryocytopoiesis is likely to involve an interplay between stem cells, stromal elements, and growth factors. Which of these cells play a primary role in the production of TPO? How is the TPO gene expression regulated? How is the TPO level in blood controlled? The mechanism of signal transduction, e.g., the structure of the TPO receptor, kinases, phosphorylation, etc., need to be defined. There is a need to characterize the properties of platelets produced in the presence of TPO and evaluate the risk of thrombosis. The cloning of TPO was first reported in the literature in June, 1994; clinical trials began in 1995, and the early results are now being published. Thrombopoietin has moved from theory to reality, and from cloning to the clinic in three short years. It appears to belong to the lineage-dominant hormones, and the results of pre-clinical studies are encouraging. While the speed of modern biotechnology from drug discovery to clinical application is impressive, experience with the therapeutic use of other cytokines indicates the need for caution. Accordingly, the focus of this initiative is on the basic biology of TPO, megakaryocytopoiesis, and platelet production, areas which are unlikely to be fully investigated by the pharmaceutical industry. Logical extension of basic studies to animal research and limited patient studies are encouraged. Examples of Research Areas The following are examples of broad areas of research interests related to thrombopoietin. Applicants are encouraged to develop their own ideas for research studies within the context of this program announcement. o Regulation of thrombopoietin expression o Regulation of c-mpl expression in different cell types o Determination of sites for binding to Mpl and signaling o Elucidation of mechanisms of interaction with other cytokines o Identification of the transcriptional targets of megakaryocyte signal transducers and transactivators o Identification of genes for megakaryocyte lineage commitment and development o Elucidation of mechanisms underlying polyploidy o Definition of action of TPO in cell proliferation o Possible role of TPO in malignancy and thrombosis o Regulation of TPO level in blood o Developmental changes and use in neonates o Elucidation of effects of TPO on cord blood cells INCLUSION OF WOMEN AND MINORITIES IN RESEARCH INVOLVING HUMAN SUBJECTS It is the policy of the NIH that women and members of minority groups and their subpopulations must be included in all NIH supported biomedical and behavioral research projects involving human subjects, unless a clear and compelling rationale and justification is provided that inclusion is inappropriate with respect to the health of the subjects or the purpose of research. This policy results from the NIH Revitalization Act of 1993 (Section 492B of Public Law 103-43). All investigators proposing research involving human subjects should read the "NIH Guidelines for Inclusion of Women and Minorities as Subjects in Clinical Research", which have been published in the Federal Register of March 28, 1994 (FR 59 14508-14513), and in the NIH GUIDE FOR GRANTS AND CONTRACTS of March 18, 1994, Volume 23, Number 11. Investigators may obtain copies from these sources or from the program staff or contact person listed below. Program staff may also provide additional relevant information concerning the policy. APPLICATION PROCEDURES Investigators who are considering preparing an application in response to this program announcement are invited, but not required, to discuss their project with NHLBI and NIDDK staff listed under INQUIRIES in advance of formal submission. Specific information on research training and career development mechanisms and eligibility may also be accessed at the following address on the NIH Home Page on the world wide web: http://www.nih.gov/grants/training/careerdev/RTCDINTRO.HTM Applications for R01 and K08 grants are to be submitted on the research grant application form, PHS 398 (rev. 5/95). Applications for National Research Service Awards (F32 and F33) are to be submitted on PHS 416-1. Application kits are available in an applicant institution's office of sponsored research and from the Division of Extramural Outreach and Information Resources, National Institutes of Health, 6701 Rockledge Drive, MSC 7910, Bethesda, MD 20892-7910, telephone (301) 710-0267, email: ASKNIH@od.nih.gov. Application receipt dates for each mechanism are listed in the application kits. To identify the application as a response to the PA, check "YES" on Item 2 of page 1 of the application and enter the title and PA number: THROMBOPOIETIN, MEGAKARYOCYTES AND PLATELET PRODUCTION, PA-98-XXX. Send or deliver the completed application and five signed, exact photocopies of it to: CENTER FOR SCIENTIFIC REVIEW (formerly Division of Research Grants) NATIONAL INSTITUTES OF HEALTH 6701 ROCKLEDGE DRIVE, ROOM 1040 - MSC 7710 BETHESDA, MD 20892-7710 BETHESDA, MD 20817 (for express/courier service) REVIEW CONSIDERATIONS Applications will be assigned on the basis of established Public Health Service referral guidelines. Applications will be reviewed for scientific and technical merit in accordance with the standard NIH peer review procedures. Applications that are complete will be evaluated for scientific and technical merit by an appropriate peer review group convened in accordance with the standard NIH peer review procedures. As part of the initial merit review, all applications will receive a written critique and undergo a process in which only those applications deemed to have the highest scientific merit, generally the top half of applications under review, will be discussed, assigned a priority score, and receive a second level review by the appropriate national advisory council or board. Review Criteria 1. Significance. Does this study address an important problem? If the aims of the application are achieved, how will scientific knowledge be advanced? What will be the effect of these studies on the concepts or methods that drive this field? 2. Approach. Are the conceptual framework, design, methods, and analyses adequately developed, well-integrated, and appropriate to the aims of the project? Does the applicant acknowledge potential problem areas and consider alternative tactics? 3. Innovation. Does this project employ novel concepts, approaches or methods? Are the aims original and innovative? Does the project challenge existing paradigms or develop new methodologies or technologies? 4. Investigator. Is the investigator appropriately trained and well suited to carry out this work? Is the work proposed appropriate to the experience level of the principal investigator and other researchers (if any)? 5. Environment. Does the scientific environment in which the work will be done contribute to the probability of success? Do the proposed experiments take advantage of unique features of the scientific environment or employ useful collaborative arrangements? Is there evidence for institutional support? AWARD CRITERIA Applications will compete for available funds with all other approved applications. The following will be considered in making funding decisions: quality of the proposed project as determined by peer review; availability of funds; and program priority. INQUIRIES Inquiries concerning this PA are encouraged. The opportunity to clarify any issues or questions from potential applicants is welcome. Inquiries regarding programmatic issues may be directed to: Dr. Pankaj Ganguly Division of Blood Diseases and Resources National Heart, Lung, and Blood Institute 6701 Rockledge Drive, Room 10146 Bethesda, MD 20892-7950 Telephone: (301) 435-0070 FAX: (301) 480-1046 Email: gangulyp@gwgate.nhlbi.nih.gov Dr. David G. Badman Division of Kidney, Urologic and Hematologic Diseases National Institute of Diabetes, Digestive and Kidney Disorders 45 Center Drive, Room 6AS-13C, MSC 6600 Bethesda, MD 20892-6600 Telephone: (301) 594-7717 FAX: (301) 480-3510 Email: David_Badman@nih.gov Direct inquiries regarding fiscal matters to: Ms. Jane R. Davies Grants Management Office National Heart, Lung, and Blood Institute 6701 Rockledge Drive, MSC 7926 Bethesda, MD 20892-7926 Telephone: (301) 435-0166 FAX: (301) 480-3310 Email: jane_davis@nih.gov Ms. Aretina Perry Division of Extramural Activities National Institute of Diabetes, Digestive, and Kidney Diseases 45 Center Drive, Room 6N-38B, MSC 6600 Telephone: (301) 594-8862 Email: perrya@ep.niddk.nih.gov AUTHORITY AND REGULATIONS This program is described in the Catalog of Federal Domestic Assistance Nos. 93.839 and 93.849. Awards will be made under the authority of the Public Health Service Act, Section 301 (42 USC 241) and administered under PHS grant policies and Federal regulations, most specifically 42 CFR Part 52 and 45 CFR Part 74. This program is not subject to the intergovernmental review requirements of Executive Order 12372, or to Health Systems Agency Review. The PHS strongly encourages all grant and contract recipients to provide a smoke- free workplace and promote the non-use of all tobacco products. In addition, Public Law 103-227, the Pro-Children Act of 1994, prohibits smoking in certain facilities (or in some cases, any portion of a facility) in which regular or routine education, library, day care, health care or early childhood development services are provided to children. This is consistent with the PHS mission to protect and advance the physical and mental health of the American people.
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