Janina Ratajczak M.D., Ph.D.


M.D., Pomeranian Medical University, Szczecin, Poland, 1982
Assistant, Department of Rheumatology Regional Hospital-Szczecin,Poland,1982-1990
Postdoctoral Fellowship, University of Pennsylvania,1991-1998
Ph.D., Medical Postgraduate Center Warsaw,Poland,1995
Research Specialist, University of Pennsylvania,1998-2001

Curriculum Vitae

Current Positions:

Assistant Professor, Department of Medicine, University of Louisville School of Medicine

Contact Information:

Developmental Biology Program Pavilion, Room 115
Brown Cancer Center
University of Louisville
500 South Floyd St.
Louisville, KY 40202, USA
Phone 502-852-8075
Fax 502-852-3032

Email: j0rata01@louisville.edu

Research Description:

Dr.J. Ratajczak joined the Brown Cancer Center in 2001 where she was appointed as Assistant Professor in the Department of Medicine and a member of the Stem Cell Biology Program.  She is widely regarded for her work in the area of hematopoietic cell development with an emphasis on the molecular basis of blood cell diseases. Her recent research includes understanding the biological significance of chemokine receptor expression in normal and neoplastic cells and mechanisms of stem cell mobilization and homing.  Dr. Ratajczak discovered horizontal mRNA transfer between cells by cell-derived extracellular microvesicles that is being celebrated as one of a major accomplishment in hematology.

Her scientific research is focused on

1. Application of stem cells isolated from the adult tissues in regenerative medicine

Identification of new mechanisms responsible for tissue/organ regeneration. Our group developed a concept of circulating small pluripotent very small embryonic-like stem cells (VSELs) and is developing new strategies to isolate those cells from bone marrow, mobilized peripheral blood and cord blood and to expand them for therapeutic purposes.

2.Molecular mechanism that regulate stem cell trafficking

Another area of investigations in our laboratory is to elucidate the role of complement proteins in regulating human hematopoiesis. Our group identified a novel role of C3 complement cleavage fragments modulate the SDF-1-CXCR4 axis and thus play an important role in retaining human CXCR4+ hematopoietic stem cells in the bone marrow. Our laboratory is elucidating the role of sphingosine-1 phosphate and ceramid-1 phosphate in regulating normal human hematopoiesis and directing mobilization and homing of BM-derived stem cells.

3. Biological effects of microvesicles

Microvesicles, isolated from embryonic stem cells, were used by our lab to improve ex vivo expansion and survival of hematopoietic stem/progenitor cells,and for a first time we have described a presence of mRNA in microvesicles and a novel role of microvesicles in horizontal transfer mRNA and miRNA between the cells.

Literature Cited:

  1. Ratajczak J,  Majka M, Kijowski J,  Baj M,. Pan ZK, Marquez LA, Janowska-Wieczorek A,  Ratajczak MZ. Biological significance of MAPK, AKT and JAK-STAT protein activation by various erythropoietic factors in normal human early erythroid cells. Brit. J. Haematol. 2001, 115, 195-204.  PMID: 11722433
  2. Kucia M, Ratajczak J, Reca R, Janowska-Wieczorek A, Ratajczak M.Z.: Tissue-specific Muscle, Neural and Liver Stem/Progenitor Cells Reside in the Bone Marrow, Respond to an SDF-1 Gradient and Are Mobilized into Peripheral Blood during Stress and Tissue Injury. Blood Cells Mol. Dis. 2004, 32, 52-7.  PMID: 14757413
  3. Ratajczak M.Z., Kucia M, Reca R, Majka M, Janowska-Wieczorek A, Ratajczak J.: Stem cell plasticity revisited: CXCR4-positive cells expressing mRNA for early muscle, liver and neural cells "hide out" in the bone marrow. Leukemia 2004, 18, 29-40.  PMID: 14586476
  4. Ratajczak J, Reca R, Kucia M, Majka M, Allendorf DJ, Baran JT, Janowska-Wieczorek A, Wetsel RA, Ross GD, Ratajczak M.Z.: Mobilization Studies in Mice Deficient in Either C3 or C3a-Receptor (C3aR) Reveal a Novel Role For Complement in Retention of Hematopoietic Stem/Progenitor Cells in Bone Marrow. Blood 2004, 103, 2071-2078.  PMID: 1460496
  5. Kucia M, Reca R, Jala VR, Dawn B, Ratajczak J, Ratajczak M.Z. Bone marrow as a home of heterogenous populations of nonhematopoietic stem cells. Leukemia 2005, 19, 1118-1127.  PMID: 15902288
  6. Ratajczak MZ, Reca R, Wysoczynski M, Yan J, Ratajczak J. Modulation of the SDF-1-CXCR4 axis by the third complement component (C3) - Implications for trafficking of CXCR4+ stem cells. Exp. Hematol 2006, 34: 986-995.  PMID: 16863905
  7. Ratajczak J, MiekusK, KuciaM, ZhangJ, RecaR, DvorakP, Ratajczak MZ. Embryonic stem cell-derived microvesicles reprogram hematopoietic progenitors: evidence for horizontal transfer of mRNA and protein delivery. Leukemia 2006, 20:847-856.  PMID: 16453000
  8. Ratajczak MZ, Zuba-Surma E, Kucia M, Reca R, Wojakowski W, Ratajczak J. The pleiotropic effects of the SDF-1-CXCR4 axis in organogenesis, regeneration and tumorogenesis. Leukemia 2006, 20:1915-1924.  PMID: 16900209
  9. Ratajczak MZ, Lee HK, Wysoczynski M, Wan W, Marlicz W, Laughlin MJ, Kucia M, Janowska-Wieczorek A, Ratajczak J. Novel insight into stem cell mobilization - Plasma Sphigosine 1 – phosphate is a major chemoattractant that directs egress of hematopoietic stem progenitor cells from bone marrow and its level in peripheral blood increases during mobilization due to activation of complement cascade/membrane attack complex.  Leukemia 2010, 24, 976-985.  PMID: 20357827
  10. Ratajczak J, Wysoczynski M, Zuba-Surma E, Wan W, Kucia M, Yoder MC, Ratajczak MZ. Adult murine bone marrow-derived very small embryonic-like stem cells (VSELs) differentiate into the hematopoietic lineage after co-culture over OP9 stromal cells.  Exp. Hematol. 2011, 39, 225-237.  PMID: 21034791
  11. Ratajczak J, Shin DM, Wan W, Liu R, Masternak M, Piotrowska K, Wiszniewska B, Kucia M, Bartke A, Ratajczak MZ. Higher number of stem cells in bone marrow of circulating Igf-1 level low Laron dwarf mice - novel view on Igf-1, stem cells and aging. Leukemia 2011, 25, 729–733.  PMID: 21233833
  12. Ratajczak J, Zuba-Surma E, Klich I, Liu R, Wysoczynski M, Greco N, Kucia M, Laughlin MJ, Ratajczak MZ. Hematopoietic differentiation of umbilical cord blood-derived very small embryonic/epiblast-like stem cells. Leukemia 2011 Aug; 25(8):1278-85.  PMID: 21483440
  13. Kim CH, Wu W, Wysoczynski M, Abdel-Latif A, Sunkara M, Morris A, Kucia M, Ratajczak J, Ratajczak MZ. Conditioning for hematopoietic transplantation activates the complement cascade and induces a proteolytic environment in bone marrow: a novel role for bioactive lipids and soluble C5b-C9 as homing factors. Leukemia 2012, 26,106-116.  PMID: 21769103
  14. Ratajczak J, Kucia M, Mierzejewska  K, Liu R, Kim CH, Natarajan N, Sharma V,  Miller DM, Maciejewski J,  Ratajczak MZ. A novel view of Paroxysmal Nocturnal Hemoglobinuria (PNH) pathogenesis: more motile PNH hematopoietic stem/progenitor cells (HSPCs) displace normal HSPCs from their niches in bone marrow due to defective adhesion, enhanced migration and mobilization in response to erythrocyte-released sphigosine-1 phosphate (S1P) gradient. Leukemia 2012, 26, 1722-1725.  PMID: 22343521
  15. Ratajczak J, Mierzejewska K, Kucia M, Marlicz W, Pietrzkowski Z, Wojakowskli W, Greco N, Tendera M, Ratajczak MZ. Paracrine Proangiopoietic Effects of Human Umbilical Cord Blood-Derived Purified CD133(+) Cells-Implications for Stem Cell Therapies in Regenerative Medicine.Stem Cells Dev. 2012 Sep 24.  PMID: 23003001

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