Ph.D., Bose Institute, Jadavpur University, India
Office Phone: (216) 687-2435
Lab Phone: (216) 523-7552
COSHP Faculty Profile
Molecular Mechanisms of Translational Control of Ceruloplasmin in Monocytes and Macrophages by 3'-UTR Binding Proteins. Research in my labotratory is supported by a Scientist Development Grant from American Heart Association & National Institute of Health RO1 Grant.
I am interested to study the molecular mechanism of atherosclerosis. In particular the post-transcriptional regulation of pro-inflammatory gene in endothelial cells and monocytes/macrophages and how this mechanism is important in the endogenous cellular strategy to control inflammation. Post-transcriptional control is a mechanism by which the synthesis of individual protein is regulated by differential efficiency of utilization of mRNA. A principal advantage of post transcription as a site of regulation is that it offers the possibility of rapid response to external stimuli without invoking nuclear pathways for mRNA synthesis and transport.
We have reported that ceruloplasmin a serum glycoprotein can oxidize low-density lipoprotein present in human atherosclerotic plaque and believed to have a role in the progression of the disease. In addition we have shown that an inflammatory cytokine, Interferon-gamma (IFN-g) induces the synthesis of ceruloplasmin mRNA and protein in monocytic cells, and that the induced synthesis of ceruloplasmin is terminated by a mechanism involving transcript-specific translational silencing. We have also shown that an RNA-binding protein which is activated by IFN-g treatment binds specifically to the 3-untranslated region (UTR) of ceruloplasmin mRNA and blocks the initiation of translation (by blocking ribosomal association). These results are consistent with the developing paradigm in which binding of a protein to the UTR of a transcript silences its translation. Recently we have screened monocyte cDNA library using yeast three-hybrid screening and identified Ribosomal Protein L13a as a molecular switch for translational silencing. Currently I am investigating the molecular mechanism of translational inhibition by L13a.
I am very much interested to translate my research to in vivo studies using mouse model of cardiovascular disease. We have shown that in human monocytes and macrophages, ribosomal protein L13a is the molecular switch for translational silencing of ceruloplasmin, an inflammatory protein that is an independent risk factor for atherosclerosis. On the basis of these findings we hypothesize that this mechanism may be important in the endogenous cellular resolution of inflammation. As an independent investigator I will test this hypothesis by targeted disruption of RPL13a in mice in an apoE knockout background. Fortunately embryonic stem cells carrying disruption of one allele of RPL13a are available from Bay Genomics. In a parallel approach, I will down-regulate RPL13a in a tissue-specific fashion in macrophages. This will be done by infecting bone marrow cells from apoE knockout mouse with lentivirus expressing the siRNA of RPL13a, and subsequent transplantation of the bone marrow in irradiated apoE mouse. Extent of plaque formation from the above mouse will be measured by aortic root analysis.
Micro-Array and Proteomics based approach to determine other target mRNAs for translational silencing. Polyribosome will be isolated from IFN-g treated monocytes, mRNAs will be isolated from treated and control, and subjected to cDNA microarray. This study may show the differential recruitment of different mRNAs in the ribosome which might discover other mRNAs regulated at translational level. (b) Total mRNA isolated from IFN-g activated monocytes will be invitro translated in presence or absence of the inhibitory activity. denovo synthesized S35 labelled proteins will be subjected to 2D gel electrophoresis any differential protein spot will be isolated and sequenced my Mass Spectrometry.
My second project is Post-transcriptional regulation of ABCA1 gene in macrophage in response to inflammatory cytokines and advanced glycation products. ABCA1 gene has been found to be responsible for incorporating lipids in to the HDL particle and activate reverse cholesterol transport, a protective mechanism against formation of atherosclerotic plaque. These findings could explain the molecular link between Diabetes and Cardiovascular Disease.
1. B. Mazumder, P. Sampath & P.L. Fox. Regulation of Macrophage Ceruloplasmin Gene Expression: One Paradigm of 3-UTR-mediated Translational Control. Molecules & Cells. 20, 167-172, 2005.
2. P. Sampath, B. Mazumder, V. Seshadri, C.A. Gerber, L. Chavatte, M. Kinter, J.D. Dignam, S. Kim, D.M. Driscoll and P.L. Fox. Non-canonical Function of Glutamyl-prolyl-tRNA Synthetase: Gene-specific Silencing of Translation. Cell, 119, 1-20, 2004.
3. B. Mazumder, P. Sampath, V. Seshadri, R.K. Maitra, P.E. DiCorleto and P.L. Fox. Regulated release of L13a from the 60S Ribosomal Subunit as a Mechanism of Transcript-Specific Translational Control. Cell, 115, 187-198, 2003. (Previewed in the same issue)
4. B. Mazumder, V.Seshadri and P.L.Fox. Translational control by the 3-UTR: The ends specify the means. Trends in Biochemical Sciences (TiBS), 28, 91-98, 2003.
5. P. Sampath, B. Mazumder, V. Seshadri and P.L. Fox. Transcript-selective translational silencing by interferon-g is directed by a novel structural element in the ceruloplasmin mRNA 3-UTR. Molecular and Cellular Biology, 23, 1509-1519, 2003.
6. B. Mazumder, V. Seshadri, H. Imataka, N. Sonenberg and P.L. Fox. Translational silencing of ceruloplasmin requires the essential elements of mRNA circularization: Poly(A) tail, Poly(A)-binding protein and eIF4G. Molecular and Cellular Biology, 21, 6440-6449, 2001.
7. B. Mazumder & P.L. Fox. Delayed translational silencing of ceruloplasmin transcript in Interferon-g activated U937 monocytic cells : Role of 3/-UTR. Molecular and Cellular Biology, 19, 6898 - 6905, 1999.
8. B. Mazumder, C.K. Mukhopadhyay, A. Prok, M.K. Cathcart and P.L. Fox. Induction of ceruloplasmin synthesis by Interferon-g in Monocytic Cells. The Journal of Immunology, 159, 1938 - 1944, 1997.