Scientists from Torrey Pines Institute for Molecular Studies (CA) and their collaborators have discovered that a long-chain sugar molecule contributes to blood cell production in the bone marrow. The study, Hyaluronan expressed by the hematopoietic microenvironment is required for bone marrow hematopoiesis, published in Journal of Biological Chemistry, could pave the way for new therapeutics that stimulate production of blood cells and improve the way that bone marrow stem cells are used to treat diseases.

In healthy people, the bone marrow produces about 500 billion red and white blood cells every day. When the bone marrow is damaged by radiation, chemotherapeutic drugs, or disease, the decrease in blood cell production can compromise the immune system and lead to lethal infections. Millions of patients around the world suffer from acute and chronic illnesses caused by blood cell deficiencies.

In the study, the international team of scientists, led by Dr. Sophia Khaldoyanidi, studied a long-chain sugar called hyaluronan, which is synthesized by many cells in the body. The team showed that mice that could not synthesize hyaluronan had defective bone marrow that was unable to retain hematopoietic stem and progenitor cells—cells that give rise to the full range of mature blood cells—and caused them to move to other organs.

Further studies showed that tight control of hyaluronan levels in the bone marrow was critical for the microenvironment to generate signals supporting stem cell function. “Our findings suggest that hyaluronan is a biologically active component of the hematopoietic microenvironment and is involved in regulating hematopoietic homeostasis,” said Dr. Khaldoyanidi. Because too much or too little hyaluronan in the bone marrow caused abnormalities in hematopoiesis, the scientists believe that biologically active forms of hyaluronan or hyaluronan synthesis-blocking drugs may have potential use in the clinic to correct misbalanced hyaluronan levels and help support blood cell production.

“Dr. Khaldoyanidi’s elegant studies provide seminal evidence of the key role of hyaluronan in the hematopoietic microenvironment. The work has profound implications for clinical practice, as it suggests that maintenance of marrow hyaluronan levels could improve blood cell development,” said Dr. Robert Sackstein, a leading bone marrow transplant physician-scientist and Professor at the Harvard Medical School.

The study was evaluated by the Faculty of 1000, in which the world’s leading scientists and clinicians identify and evaluate the most important articles in biology and medical research. “The fact that the Faculty of 1000 is now paying attention to hyaluronan research is great. As most of us in the field know, it has been difficult at times to get the broader research community to pay attention to hyaluronan matrices and their roles in normal and pathological processes,” said Vincent Hascall, PhD, Professor and Head, Section of Connective Tissue Biology, Cleveland Clinic Lerner Research Institute.

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