AL Amyloidosis
Much of our basic laboratory research on AL amyloidosis has been supported by a “Program Project” multi-laboratory grant from the National Heart, Lung, and Blood Institute at the National Institutes of Health. This Program Project has supported a team of independent research investigators from diverse science backgrounds in the Departments of Medicine, Pathology, Biochemistry, Biophysics and Environmental Health at the Boston University School of Medicine and School of Public Health. The overall theme of the Program is to understand the structural features of amyloidogenic light chains that permit fibril formation in the tissue microenvironment that lead to amyloid deposition. A major goal of the Program is to develop targeted interventions and bring them to the pre-clinical testing stage.
The leader of the first project is Dr. Seldin. He and his co-investigators including Drs. Tatiana Prokaeva and Jennifer Ward are examining the gene structure and germline origin of amyloidogenic light chains found in our referral population of patients with AL amyloidosis. To date, >200 amyloidogenic light chain genes have been sequenced. Sequences are being correlated with organ system involvement based on the hypothesis that light chain sequence determines organ tropism. The Project 1 group is continuing to test expression vectors for light chain production in vitro and has found the CMV promoter confers excellent expression. They have stably transfected a λ6 light chain into SP 2/0 cells and transplanted these cells into mice. Recipients express λ6 light chain and show organ pathology.
The leader of the second project is Dr. Skinner. Her team, which includes Drs. Douglas Sawyer, Lawreen Connors, Carl O’Hara and Vickery Trinkaus-Randall, along with mass spectrometrists Dr. Catherine Costello and Dr. Roger Theberge, is examining post-translational modifications in the amyloidogenic light chains, their influence on the host tissue, and the physiologic tissue effects caused by the light chains. To date, 16 light chains have been partially or completely studied; all have post-translational modifications that likely contribute to their amyloidogenic propensity. Very good progress is being made on studies examining the cellular response of cardiac fibroblasts to amyloidogenic (or modified) light chains. Light chains were found to localize within cells and mediate the expression of heparan sulfate proteoglycans. In other studies, the team found that isolated cardiomyocytes showed oxidant stress when incubated with light chains from patients with cardiomyopathy. This reaction was independent of amyloid fibril deposition and suggests antioxidant therapy may be beneficial for patients with amyloid cardiomyopathy.
The leader of the third project is Dr. David Sherr, the head of the laboratory research program at the BU School of Public Health. Dr. Sherr’s team is examining novel immunotherapy approaches to treatment of AL amyloidosis. They have looked at patient bone marrow plasma cells for their suitability as targets for T cell killing. They have performed three color flow cytometric analyses and determined that the high level of CD38 expression provides a means for quantifying the percentage of neoplastic plasma cells in the bone marrow. To define strategies for immunotherapy, they have used 2 colonies of HLA-A2 transgenic mice and performed over 20 peptide immunization protocols. They determined an optimal protocol for eliciting CTL responses against peptides restricted to binding human HLA-A2 MHC class I.
This research program is supported by two core laboratories. Core A is co-directed by Lawreen Connors, Ph.D., a biochemist with expertise in purification of amyloid proteins, and Carl O’Hara, M.D., the chief of hematopathology, who has expertise in bone marrow plasma cells and tissue amyloid deposition. Core A is supporting all Projects with biochemical and histological analyses.
Core B is directed by Catherine Costello, Ph.D., a biophysicist and biochemist who also directs the mass spectrometry resource at Boston University School of Medicine. Dr. Costello and Core B support all Projects with mass spectrometry analyses including protein sequencing.
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